To investigate the relationship between neural function and behavior it is necessary to record neuronal activity in the brains of freely behaving animals, a technique that typically involves tethering to a data acquisition system. Optimally this approach allows animals to behave without any interference of movement or task performance. Currently many laboratories in the cognitive and behavioral neuroscience fields employ commercial motorized commutator systems using torque sensors to detect tether movement induced by the trajectory behaviors of animals.In this study we describe a novel motorized commutator system which is automatically controlled by video tracking. To obtain accurate head direction data two light emitting diodes were used and video image noise was minimized by physical light source manipulation. The system calculates the rotation of the animal across a single trial by processing head direction data and the software, which calibrates the motor rotation angle, subsequently generates voltage pulses to actively untwist the tether. This system successfully provides a tether twist-free environment for animals performing behavioral tasks and simultaneous neural activity recording.To the best of our knowledge, it is the first to utilize video tracking generated head direction to detect tether twisting and compensate with a motorized commutator system. Our automatic commutator control system promises an affordable and accessible method to improve behavioral neurophysiology experiments, particularly in mice.The online version of this article (doi:10.1186/s13041-015-0152-8) contains supplementary material, which is available to authorized users. Though a motorized commutator based on a hall-effect sensor was previously developed [To study neural function and its behavioral relevance in cognitive and behavioral neuroscience fields it is crucial to record neuronal activity in freely behaving animals –3. Receneveloped , most moThe commutator system we designed allows for active correction of tether-twisting as a result of behavior via feedback from a video-tracking system. As diagramed in Fig. To improve the SNR of the video images we first manipulated the tracking LEDs mounted on the mouse’s head. Since it is impossible to control the intensity of the commercial LEDs we covered them physically with layers of paraffin film to attenuate the center points’ intensities to prevent saturation. Although we used a narrow 2 mm diameter tether  the tether occasionally occluded the LEDs, thus we added curved aluminum reflectors behind the LEDs to widen their spatial coverage Fig.  inset. Th) by adjusting the focus level of camera manually to be slightly out of focus to get pre-smoothing filtered images  to connectors  compatible with the existing amplifier system . To drive rotation of the commutator a DC motor  with a small pulley attached to the motor shaft was coupled to a larger pulley glued to rotary joint which connected to the tether . The commercially available DC motor driver was designed based on TB6612FNG chip  providing bidirectional control (clock- and counter clock-wise). Next we connected the output terminal of the digital IO device  to the motor controller in order to operate the DC motor  and the midline of animal , which is orthogonal to the axis passing both LEDs in the video image Fig. . The tran = 15) and CCW (n = 16) show no significant change of direction after motor rotation  needs to be removed or minimized. We adopted physical manipulation of light sources (LED) combined with defocused video recording . The noise reduction strategy we describe may be applied to general video tracking to improve raw data quality of head position and direction irrespective of the use of a wired or wireless recording system –3.However, there will be additional modification required to improve the performance of the commutator and to make it into an independent module that can be flexibly integrated into any neural recording system. Currently the commutator uses a commercial neural recording system equipped with video tracking to generate head direction values. In the future, single board computers providing internal program customization and digital output ports may be integrated in this system to remove this dependency . MoreoveCommercial DC motors are cheap and easy to drive, but difficult to precisely control angular positions. Other types of advanced motor systems, such as stepper motors and drivers, may be used to achieve exact angular control without requiring any calibration procedures .In the behavioral task used in this study, animals are required to move specific location of the chamber to initiate, choose, and receive a reward. The rotation counting algorithm was designed based on this behavioral task. Animals spend most of time consuming reward, so a virtual rectangular box around the reward port was set and tether is untwisted as soon as animals enters the box. This, however, can be a problem when animals spend more time outside the box while rotating toward a single direction. Although animals seem insusceptible to a single twist of tether, continuous control of commutator is desirable. To become an independent modular system, this feature will be necessary. Moreover, the system may be further improved in combination with tagging-free video tracking techniques by eliminating light sources on the headstage and adopting computerized video analysis or tracking techniques using accelerometers –11.In this study, we developed a motorized commutator system which is automatically controlled by video feedback. Previously developed motorized commutator systems employ torque sensors to detect tether twist, which can be effective but faces limitations, especially in smaller rodents. Here we used head directions computed by video tracker system to detect tether twist and use this information to correct the tether position on a trial-by-trial basis. This system successfully provided tether twist-free environment for animals performing our behavioral task during acquisition of neural activity data.n = 2) weighing 20 ~ 25 g were used in this study. Mice were housed individually in a Plexiglas cage under 12 h/12 h light–dark cycle. Water was limited but food was available ad libitum and body weights were maintained about 80 % of free-feeding weight. All procedures regarding animal care and handling were approved by the Institution of Animal Care and Use Committee of Kyungpook national university (South Korea) and all experimental protocols were performed in accordance with the guidelines for the Care and Use of Laboratory Animals of the National Institutes of Health (USA).Male C57BL6/J mice . Deep anesthesia was confirmed by tail and paw pinches, which resulted in no withdrawal behavior. Then mouse head was fixed on a stereotaxic apparatus. Ophthalmic ointment was applied to prevent from drying eyes. After shaving and midline incision, skull surface was cleared using saline. Periosteum was scrapped off and holes were drilled and screws were implanted. A microdrive having 8 tetrodes was implanted above the M1 cortex targeting striatum, and dental cement was applied. After 1 week of recovery period, mouse was introduced to behavioral task.The schematic drawing of behavioral chamber, which is a modified version used for 5-choice serial reaction time task, is depicted in Fig. First step: refinement of the video tracking to improve the accuracy to detect behavioral parameters such as X, Y coordinates or head-directionsSecond step: mechanical assembly of commutator systemThird step: development of algorithm to compute and judge whether or not the animal has made a turnFinal step: calibration of commutator with open loop trackingLED manipulation for video noise reductionFor video tracking, we used digital amplifier  with a headstage with two LEDs, red and green mounted alongside . Since it is impossible to control the intensity of the commercial LEDs, we covered the LEDs physically with layers of paraffin films to attenuate the center points’ intensities of LEDs to prevent saturation. Although we used a 2 mm diameter tether , sometimes the tether positioned between LEDs and camera, obstructing LED detection. We therefore added the curved aluminum reflectors behind LEDs to widen the spatial coverages of LEDs Fig.  inset.The position of LEDs were adjusted to be perpendicular to animal’s rostro-caudal axis, that is, red and green LEDs were positioned left and right side of the animal’s head, respectively Fig.  inset. TImproving SNR by image smoothingh). The camera provided a dial to control the focusing level manually, so we adjusted the level slightly out of focus to get pre-smoothing filtered images. For general behavioral monitoring purposes, we used an additional video camera.Since the behavioral chamber had glossy walls which could reflect the LEDs, causing errors in detection, the walls were matted via abrasion. In the altered chamber the reflected LED light was diffuse and its intensity was attenuated. To improve the SNR of video image, we smoothed incoming images at the initial sensing stage Fig. .h. The ce). The wires of both ends were soldered to connectors  which matches to the adapter of existing amplifier system .We used 56 circuits slip-ring , a pulley of diameter 60 mm was glued to rotary joint which connected to tether . A small sized pulley (diameter of 6 mm) was attached to the DC motor shaft. Those two pulleys were linked using a rubber belt so that motor power was transferred through the pulley. The distance between center points of each pulley was approximately 85 mm.To rotate it using a DC motor . It provides bidirectional control (clock- and counter clock-wise) using two TTL channels. To control the DC motor, the output terminal of the digital IO device  was connected to the motor controller through cables  and steel posts  as shown in Fig. The head position is defined by the mid-point between the LEDs. The head direction is defined by the angle composed of a reference line  and the midline of animal , which is orthogonal to the axis passing both LEDs from the video image. We took advantage of the data acquisition software, Cheetah . Tracking parameters were then obtained at 29.97 fps (frames per second) and streamed to processing computer through a NetCom library  for online processing. Customized software was designed using Labview  to apply the algorithm described below.The behavioral task consisted of a single trial repeated many times during a daily session. Across the entire session the mice spent the majority of their time near the starting position, therefore we set a virtual rectangle near the starting position in the video image Fig. . The reci.When the mouse occupies the starting position, wait.ii.As soon as the mouse departs the starting position, stores a trajectory of head direction until the mouse comes into the position back.iii.A.Count CW rotation (RNCW)B.Count CCW rotation (RNCCW)C.Total rotation number (TRN) is then TRN = RNCW - RNCCW.Compute rotation number (RN) from the trajectory.iv.Generate motor command for the given TRN.In summary, algorithm to detect whether a mouse rotated is as follows Fig. .i.When tTo drive the DC motor, we used pulse modulated control. We set single pulse duration as 100 ms, and changed its duty cycle. Then we generated a series of pulses, a pulse train, to drive the motor. As described above, actual disentanglement of tether is carried out when the mouse is in the start position, rewarding and/or initiating the next trial. Therefore, it is important to rotate the DC motor exactly 360°. Detailed calibration procedures are described in the next section.There are two parameters to control the motor angles, the pulse width and the number of pulses. Therefore, by inspecting the combination of both parameters, it is possible to rotate the tether close to 360°. Initially we set the pulse width as 20 ms, that is, duty cycle of 20 %. Then pulse trains of having 20 to 30 pulses were transmitted to motor controller. We found that 26 pulses made one rotation nearly perfectly. The given pulse trains were further validated by sending it repeatedly, under simultaneous online recording of its angles. We checked the angle difference before and after motor rotation.Finally, the designed system was applied to mouse performing behavioral tasks which lasted approximately 50 min and composed of more than 100 trials.


Background. Normative feedback (NF), or receiving information about one’s drinking compared to peer drinking norms, is one of the most widely used brief interventions for prevention and intervention for hazardous alcohol use. NF has demonstrated predominantly small but significant effect sizes for intention to change and other drinking related outcomes. Identifying mechanisms of action may improve the effectiveness of NF; however, few studies have examined NF’s mechanisms of action, particularly among adults.Objective. This study is an exploratory analysis of two theorized mechanisms of NF: discrepancy  and belief in the accuracy of feedback.Method. Using Amazon’s Mechanical Turk, 87 men (n = 56) and women (n = 31) completed an online survey during which they were asked about their perceptions about their drinking and actual drinking behaviors. Then participants were provided tailored NF and evaluated for their reactions. Severity of discrepancy was measured by the difference between one’s estimated percentile ranking of drinking compared to peers and actual percentile ranking. Surprise and worry reported due to the discrepancy were proxies for personal dissonance. Participants were also asked if they believed the feedback and if they had any plans to change their drinking. Mediation analyses were implemented, exploring whether surprise, worry, or belief in the accuracy of feedback mediated severity of discrepancy’s impact on plan for change.Results. Among this sample of adult drinkers, severity of discrepancy did not predict plan for change, and personal dissonance did not mediate severity of discrepancy. Severity of discrepancy was mediated by belief in the accuracy of feedback. In addition, viewing one’s drinking as a problem prior to feedback and post-NF worry both predicted plan for change independently.Conclusions. Results revealed that NF may not work to create personal dissonance through discrepancy, but belief in the accuracy of feedback may be important. It appears the more one believes the feedback, the more one makes a plan for change, suggesting practitioners should be mindful of how information within feedback is presented. Findings also indicate NF may work by validating a preexisting perception that drinking is a problem instead of creating concern related to discrepancy where none existed. Limitations regarding generalizability are discussed. Hazardous and/or harmful use of alcohol, such as drinking to excess or in the context of comorbid medical or mental health conditions, is a public health problem that causes economic and social burden across the globe , 2014. ISeveral brief interventions have been developed , 2014 toThere are a variety of forms of NF, and it is implemented in a myriad of ways. For example, NF can be implemented as a standalone intervention; as part of more detailed feedback that includes information on health consequences, referred to as personalized feedback , 2005; oIt is important to note that the preponderance of the above described research on NF has primarily focused on college students and/or their non-college same-age counterparts , 2013. TWhile NF is considered an effective intervention, particularly for individuals in late adolescence, it can potentially be improved to better facilitate both individual and population health , 2014. WOne way to improve an intervention is to understand its mechanisms of action. If one identifies and understands how an intervention works, one can hone the intervention—improving its efficacy and cost-effectiveness. Although some studies have examined the mechanisms of action of personalized feedback , 2014 anTwo potential mechanisms of action of NF explored in the literature are (1) discrepancy, including both external discrepancy , 2004, tDiscrepancy has been explored in a number of ways due to its different forms and definitions. Social Norms Theory , 2003 ispersonal dissonance. Only two studies thus far directly examined the affective response related to NF and drinking with any population  may also mediate NF’s efficacy. Decision dilemma theory (DDT) is a behavioral economic theory that posits that poor decision making  results from receiving “equivocal” feedback , 1987 oralcoholscreening.org, we explored whether it was possible to gather data about personal reactions to feedback and test the mechanisms of action of web-based NF with a heterogeneous sample of drinkers. In this feasibility study, personal dissonance, as defined by level of surprise and worry, and belief in the accuracy of feedback were tested as mediators of severity of discrepancy (the magnitude of the difference between one’s drinking and peer norms) on a drinker’s plan to reduce drinking. It was hypothesized that both personal dissonance and belief in feedback would emerge as mediators of severity of discrepancy predicting planning for behavior change.The current study aimed to expand the limited knowledge about the potential mechanisms of action within NF, specifically affective responses to NF and belief in the accuracy of the feedback, by implementing a feasibility and exploratory pilot study of NF on adult drinkers. Given that many individuals with varied drinking patterns are receiving feedback via online mechanisms, such as Participants were recruited through Amazon Mechanical Turk (MTurk), an online labor market. MTurk is a online platform through which “workers” are contracted to complete tasks, called “human intelligence tasks” (HITs), such as beta testing software or providing consumer opinions. For completing a HIT, workers are compensated by the publisher of the task, called “requesters.” Compensation is generally low—often times below $1—and commensurate with the task intensity. Increasingly, MTurk is being used for social sciences research with comparable results to more traditional sampling methods, when validity checks are included in the design , 2014.Participants were workers registered on MTurk. To participate in this HIT, they had to have received a HIT approval rating of 95% out of at least 500 completed HITs by other requesters. This limited the sample to workers deemed acceptable by other requesters and with adequate literacy in computer and internet use—thus providing increased assurance that participants could optimally understand this computer based intervention. Eligibility was limited to those residing in the United States.Answer questions about a health behavior and receive feedback. Within the HIT, participants were directed to a link to an external web-based survey, hosted by SurveyMonkey.com. The initial page of the web-based survey provided information about the study, and only those who consented to participate clicked through to the actual survey. Within the survey, participants answered the question: “Do you drink alcohol?” Participants who answered no (N = 38) were directed to a survey related to exercise and were excluded from this analysis. Those who responded yes were directed to a survey about alcohol, which included NF about their own use (described further below). At the end of the survey, participants were provided with the reference information for the data used in the feedback. The survey took about 6 min to complete. Once completed, participants were provided with a code for their MTurk account, signaling the requester to review the responses and approve compensation. Participants were compensated 50 cents for survey participation, an average rate of compensation for comparable tasks. Workers were barred from retaking the survey.Eligible workers viewed the advertisement for the HIT Participants were asked their age and gender.excessive) and whether their current drinking is a problem for them or others (problem for others) in their lives. Finally, drinkers were asked “When you have not planned to drink, how much effort does it take for you not to drink alcohol when it is presented to you?” (effort). The effort question attempted to capture level of control over drinking.Participants were asked a number of questions about their perception of their drinking prior to NF. On a scale of 1  to 8 (Extremely), participants were asked if the amount that they drank was excessive  and (2) how much does the feedback worry you? (worry). These were used as proxies for personal dissonance resulting from NF.Immediately after feedback was provided, participants were asked to rate, again on a scale of 1  to 8 (Extremely), (1) how surprised are you by the feedback?  no change in drinking to (3) quitting drinking. Participants were also asked to rate on a scale of 1  to 8 (Extremely) their To avoid biasing item responses earlier in the survey, the last question was “how accurate does the information you received about your drinking seem to you?” A 5-point Likert response scale included anchors –2 Not at all accurate to 2 Definitely accurate. Zero was “Not sure.”Severity of discrepancy was calculated as the difference between the participant’s initial reported percentile rank and actual percentile rank —a measure similar to those used in other studies  ranged in age from 18 to 64 . Sixty-four percent were male.Participants  and women (>7 standard drinks per week).Based severity of discrepancy score.There were no gender differences on any of the perception variables. Reactions to NF are shown in Drinking is a problem was significantly negatively correlated with surprise and significantly positively correlated with worry, belief in the accuracy of feedback, and effort. Drinking is a problem was also significantly negatively correlated with severity of discrepancy. Findings suggest when an individual viewed his or her alcohol use as problematic, there was higher accuracy in his or her estimate of how his or her drinking compared to the norm. As a result, feedback was believable and not a surprise.Correlation coefficients between pre-NF perceptions of drinking and the mediators were generated see . DrinkinDrinking is a problem prior to NF was significantly and strongly correlated with plan for change .There was no total effect of worry or surprise on plan for change. For this sample, personal dissonance did not mediate the effect of severity of discrepancy on making a plan for change.belief in the accuracy of feedback. Severity of discrepancy was significantly negatively associated with belief in the accuracy of feedback. There was a significant indirect effect for belief in the accuracy of feedback . The kappa-squared statistic revealed that the indirect effect is 11.6% of its maximum possible value .plan for change and severity of discrepancy, it is possible that other baseline variables impact plan for change. Given the relationship between pre-NF drinking is a problem to post-NF plan for change, post hoc analyses were implemented to further explore this relationship. Drinking is a problem was independently tested as a predictor of plan for change using stepwise linear regression.Since this was a sample of mostly light to moderate drinkers, rather than predominantly hazardous drinkers, it was surprising to discover such a large proportion of them (26.4%) reported planning at least some change in their drinking. Due to the absence of a relationship between drinking is a problem significantly predicted plan to change . When post-NF worry was entered as a second step in the model, both remained significant  = 26.8, p < .001), suggesting that both baseline perception that drinking is a problem and post-NF worry predict plan for change. Tolerance statistics demonstrated no multicollinear effect.Pre-NF severity of discrepancy was not associated with plan to change, which is inconsistent with previous studies on college students  may be critical for maximum effectiveness of NF among adults. In addition, exploring with drinkers how much they are already perceive their drinking to be a problem may help to potentiate the effects of the simplest form of NF. These are relatively minor and feasible changes to NF that may in fact help to increase its efficacy rate, potentially helping to reduce the prevalence rate of hazardous alcohol use or prevent the development of AUD across a wide group of drinkers.10.7717/peerj.2114/supp-1Supplemental Information 1Click here for additional data file.10.7717/peerj.2114/supp-2Supplemental Information 2Click here for additional data file.


Aims and method To address the gap in qualitative research examining patients' experiences of ward rounds. In-depth interviews were conducted with five in-patients on an acute mental health ward. Data were analysed using thematic analysis.Results Data were organised into three first-order themes, positioned within an overarching theme relating to patients' perceptions of the use of power and control within ward rounds.Clinical implications Systemic factors may make it difficult to facilitate ward rounds in a manner which leaves patients feeling fully empowered or in control, but there are practical measures to address these issues, drawn from participants' accounts. This study aims to address this need. It was carried out in an acute in-patient unit located in a district general hospital in the north west of England. The need for this project to take place was identified by the unit's psychiatry team, who wished to investigate how ward rounds could be adapted to facilitate patient satisfaction. It was also hoped the project might identify avenues of investigation for future researchers, as per Labib & Brownell's suggestions.3Ward rounds are seen as a key component of care provision in in-patient psychiatric settings.Participants were recruited from across three mixed-gender adult acute mental health in-patient wards attached to a general hospital. Each ward has a different consultant attached. Ward rounds within this unit are chaired by psychiatrists and bring together information from members of the multidisciplinary team , followed by a direct review of the patient's progress and mental state, formulating risk and developing treatment plan changes accordingly.Patients from the wards were eligible to participate if they had experienced two or more ward rounds. Although nine responded favourably and completed informed consent forms, four did not participate: two were unavailable on the days they were due to be interviewed, one declined to take part when approached by the interviewer, and one chose to terminate her interview citing her mental state as non-conducive to participation. Detailed characteristics of the five participants are presented in Ethical approval was granted from a local research ethics committee and research and development department. Participants were recruited following an initial approach being made by an assistant psychologist. All participants were interviewed in the ward's ‘quiet room’ by R.C., using an interview topic guide (questions included ‘Tell me how you've found the ward rounds here so far’ and ‘How do you feel when you're in the ward round?’). Interviews lasted between 30 and 45 min, were audio-recorded and were transcribed verbatim.6 Data analysis followed the four conventions for thematic analysis suggested by Braun & Clarke.6Data were analysed using thematic analysis, a flexible approach for organising large amounts of qualitative data.Familiarisation with the data, re-reading transcripts looking for patterns and meanings.7 For example, initial codes from patient C's transcript, such as ‘feeling intimidated’ and ‘not being co-operative backfires’ were subsumed under the second-cycle code ‘serious consequences to not behaving in the right way’.Generating initial codes: organising the data into groups according to content and meaning. Transcripts were then re-coded and initial codes were grouped into ‘second-cycle’ codes.Searching for themes: second-cycle codes were grouped together into broader themes and subthemes. For example, codes such as ‘staff as a supportive network’ and ‘approval means more within a good relationship’ were grouped together in the development of a theme about the importance of relationships.Reviewing themes: ensuring each theme was coherent and that themes capture the essence of the data. At this point the theme ‘power and control’ was identified as an overarching theme and remaining themes designated as first-order themes.Coded transcripts and themes were reviewed by the research team to ensure analysis possessed sufficient quality and rigour.6As the analysis of participants' accounts progressed, data were organised into an overarching theme running throughout the data, representing the data at the highest level of abstraction, and first-level themes representing participants' accounts in less abstract, more concrete ways. The terminology of ‘overarching themes’ and ‘levels of themes’ is derived from Braun & Clarke.‘Well … they can be scary at first … 'cos there's all different people there, you've got support workers, staff nurse there, there's your consultant, there's a SHO  there, you can have students there, I could be there, my parents could be there. So it's like a lot of people in the ward review and, er, it's like they're all talking about you’ (patient E).This theme concerns how the majority of participants felt that the ward round process does not take the patient's emotional state into account and actually increased their anxiety at times when it was already high. The theme's title is a quote from patient C, who reported unease at ‘probing’ questions in the ward round when he was also experiencing feelings of paranoia. Participants frequently admitted to anxiety about discussing personal issues with a group of people, some of whom were unknown to the participant:‘ … they use all this, all this jargon, and you know, when your head's up your arse so to speak, you don't take much of it in, you're just looking at a load of professionals and you don't know what they do.’Another point raised in relation to this theme was the timing of information-giving about the ward round. For example, patient B stated that when the ward round process was initially described to him:For patient B, information about the ward round which would have helped ameliorate anxiety was given at a time (and by a means) that did not take account of his mental state at that point.Participants felt that staff held control over ward round processes and wished for more involvement. Participants described a lack of collaboration in the area of decision-making, where they felt their views were often not taken into account and that decisions were made away from them, without their involvement.‘ … it's like most of the things they're behind closed doors, and, and then they let you know, in your review they let you know “right we're going to follow this, we're gonna review this”.’ (patient E)‘I think as well you should get like a copy of what they've wrote [sic] (…) 'Cos you don't know what they write down and stuff, I reckon they should tell you what they've wrote down so you could like read it for a bit and then next week feed back on what they've said and maybe like, like add things to it or develop what they've wrote.’However, some participants devised ways of being able to have more input into the process, within the parameters they were confronted with. Patient C articulated this using a ‘game playing’ metaphor: ‘it's gotten better now because I've just got some leave you see but I wasn't entirely aware of how to play the game’. This was linked to the idea of having to adhere to unwritten rules of behaviour in the ward round: ‘there was a charge nurse in the last ward who was getting very frustrated with me because she was trying very clearly to show me the right way to behave and I was digging my heels in’. This resulted in what patient C described as a ‘meet you halfway situation, where if I cooperate with their goals they'll offer me incentives’.For patient A, the way in which events during ward rounds are documented was an area where control lay with staff and where she wished for more input and collaboration:‘Like I say, he listened. That's the main thing. And when you're in. . when you're in the kind of situation I'm in at the moment, if people listen to you it's half the battle, when you've got someone you can talk to, and I felt I could talk to that doctor and he listened.’Participants stressed the importance of good relationships with staff and that such relationships had a positive impact on their ward round experiences. The theme is named after a quote from patient D, who said:‘If you're close to that member of staff and they're sat at the side of you and if you were both speaking together … Like that would be good. 'Cos you'd feel like somebody's there for you, like, rather than being on your own.’However, patient A also added that the parameters of these helpful relationships were controlled by staff, who may not always recognise the positive effects of staff relationships on ward round experiences. This could result in the ward round being set up in a way which does not take account of the importance of relationships for patients, for example when there are short-notice changes to which staff attend: ‘it's nerve-wracking enough going into your ward review and then at last minute, “oh yeah by the way, such and such a person isn't coming, this person's coming in”.’Patient A described finding the ward rounds themselves daunting, but expressed a wish to use positive relationships she'd formed with staff to help her cope with them:The themes so far can be understood as part of an overarching theme relating to power and control. Issues of power and control were implicit within many issues that participants raised. The quote in this theme's name originates from patient E's interview, and relates to how some participants described their awareness during ward rounds that staff have the power to decide if they stay in hospital or leave.Participants often talked about issues of power and control by describing staff in terms of police or other agents of the law. For example, while describing being assessed in ward rounds, patient C stated: ‘yeah, it's kind of the feeling where, I don't know if you've ever been stopped by the police but they do that kind of thing, you can feel them looking up and down at you … ’. Such comparisons seemed to arise from participants' awareness of the assessment function of ward rounds and professionals' power to determine the outcomes of these assessments. Patient B described how this awareness led to anxiety about the outcome of ward rounds: ‘ … at first, it's like having to tell these people here, if I tell them I'm having these mad thoughts, they're gonna lock me up forever’. As described in the first-level themes, participants felt that professionals hold power and control over how the ward round, and therefore the assessment process within it, is conducted. However, as indicated by the first-level theme ‘the power of relationships’, participants suggested these issues could be ameliorated by positive, collaborative relationships with staff.‘ 'Cos my personal experience of walking into a room with loads of people is walking into a courtroom … 'Cos they sent me to jail. So, I didn't have a very good experience of loads of people if you like.’This account suggests that some ward round procedures may evoke patients' negative memories of encounters with powerful figures.Patient B also described how interpretations of the actions and intentions of those in the ward round may be influenced by previous encounters with those in authority:Participants seemed eager to share their ideas about practical improvements that could be made to ward rounds . Indeed,Box 1 Participants' suggestions for improvements to ward roundsAllow patients access to ward round records and the power to negotiate additions to themInvite a smaller number of staff into patients' initial ward rounds and increase the number graduallyBe open about when patients are being assessed on particular areas of their mental state and whyUtilise patients' one-to-one time with named nurses so ward rounds can be prepared forIssue patients with a booklet about hospital procedures on admission, including information about ward rounds. This would serve as an aide memoire for patients to return to so they can remind themselves of ward round procedures5 In support of previous findings linking ward round size to patient anxiety,8 participants in this study also spoke of the difficulties in talking to a room containing a large number of people unknown to them. Participants also reported that ward rounds are more distressing if they are already in an anxious or distressed state, an association which has not yet been studied in the quantitative literature. Findings from this study suggest that a lack of well-timed information about ward rounds could also contribute to anxiety.Our participants' accounts lend support to past research indicating that patients may find ward rounds anxiety provoking.As hoped, using qualitative methods led to a deeper understanding of participants' ward round experiences than has previously been possible using quantitative methods. It was hoped that more participants would be recruited but this proved difficult within the time available, owing to potential participants' apparent fluctuating mental state and their availability and motivation to take part. Although this is an exploratory study with a small sample, the findings highlight previously unexplored issues that may deserve further investigation. One such area is that of the potential importance to patients of their relationships with professionals and how sensitive use of positive relationships may positively affect the ward round experience. For example, future research might investigate whether anxiety in ward rounds is mitigated by the presence of patients' favoured members of staff, such as named nurses or key-workers.Study results and participants' suggestions for improvements to ward rounds were fed back to the research site's consultant psychiatrists. This generated discussion around how the practical measures suggested by participants  may provUsing qualitative methods to investigate acute mental health in-patients' experiences of ward rounds led to a richer understanding than has previously been possible using quantitative methods. The findings suggest possible directions for future research into ward rounds and prompted clinical discussions that have informed changes to ward round practice at the research site.


Cryptocercus punctulatus and Parasphaeria boleiriana are two distantly related xylophagous and subsocial cockroaches. Cryptocercus is related to termites. Xylophagous cockroaches and termites are excellent model organisms for studying the symbiotic relationship between the insect and their microbiota. In this study, high-throughput 454 pyrosequencing of 16S rRNA was used to investigate the diversity of metagenomic gut communities of C. punctulatus and P. boleiriana, and thereby to identify possible shifts in symbiont allegiances during cockroaches evolution. Our results revealed that the hindgut prokaryotic communities of both xylophagous cockroaches are dominated by members of four Bacteria phyla: Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Other identified phyla were Spirochaetes, Planctomycetes, candidatus Saccharibacteria (formerly TM7), and Acidobacteria, each of which represented 1–2% of the total population detected. Community similarity based on phylogenetic relatedness by unweighted UniFrac analyses indicated that the composition of the bacterial community in the two species was significantly different (P < 0.05). Phylogenetic analysis based on the characterized clusters of Bacteroidetes, Spirochaetes, and Deltaproteobacteria showed that many OTUs present in both cockroach species clustered with sequences previously described in termites and other cockroaches, but not with those from other animals or environments. These results suggest that, during their evolution, those cockroaches conserved several bacterial communities from the microbiota of a common ancestor. The ecological stability of those microbial communities may imply the important functional role for the survival of the host of providing nutrients in appropriate quantities and balance. Isoptera), cockroaches, and mantids form a well-established lineage of insects, the Dictyoptera. In fact, termites are actually social cockroaches  was used to obtain the neighbor-joining (NJ) distance matrix for each alignment. Both matrices were subsequently used to obtain rarefaction curves at different distances  and several diversity indices using Mothur1.36.1. Taxonomy was assigned by the Silva database [http://www.arb-silva.de] [Cryptocercus and Parasphaeria was evaluated using the UniFrac Server [A multiple alignment was constructed for each dataset using the secondary-structure aware infernal aligner  combinedilva.de] . Communic Server .P < 0.05 was considered statically significant). A principal components analysis (PCA) was performed to describe the relative abundance at Family level for the Cryptocercus  and Parasphaeria cockroaches. PCA data were treated with the pairwise and standardized options. Two components were extracted, and they accounted for 78.86% of the variability in the data.Relative abundance of class-phyla data were analyzed using the statistical program R v3.1.3. Kolmogorov-Smirnov test, a nonparametric test, were used to determine statistically significant difference between two samples based on a confidence level of 95.0%  were defined for multiple cutoffs up to the distance threshold . Rarefaction curves allowed the calculation of OTU richness for both the Cryptocercus and the Parasphaeria hindgut.After quality control filtering see , 3519 anCryptocercus and Parasphaeria respectively were obtained. The representative reads (the longest read of each OUT defined at 97% sequence similarity) are compared to the SILVA reference datasets of the small- (16S/18S) subunit rDNA. The most abundant bacterial phyla in both cockroaches were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. The phylum Firmicutes was dominated by members of the Clostridia class, and Bacteroidetes mostly by members of the class Bacteroidia. The class profiles of Proteobacteria differed between Cryptocercus and Parasphaeria. In Cryptocercus, Alphaproteobacteria and Betaproteobacteria dominated whereas in Parasphaeria, members of the Alphaproteobacteria were the most abundant, followed by Deltaproteobacteria, and Gammaproteobacteria (candidatus Saccharibacteria (formerly known as Candidatus Division TM7) were present in Cryptocercus  but not in Parasphaeria. In Cryptocercus and Parasphaeria, spirochetes represented 1–2% of the total bacterial population. Elusimicrobia phyla (formerly Termite Group 1) represented less than 1% of the total bacterial population in Cryptocercus but they were not detected in Parasphaeria. On the other hand, Parasphaeria contained Deferribacteres and Fibrobacteres that represented less than 0.5% relative abundance Bacteria. Relative abundance class-taxon from Crytocercus was compared with relative abundance class-taxon from other Cryptocercus metagenomes deposited on the NCBI base data. A total of 5 different populations of Cryptocercus were analyzed  between Cryptocercus and CP-1; Cryptocercus and CP-2; Cryptocercus and CP-3 and Cryptocercus and CP-4. But there were significant differences (P < 0.05) between Cryptocercus and Parasphaeria . PCA analysis revealed similarities among the bacterial microbiota of the different Cryptocercus metagenomes analyzed , indicating that a reasonable number of OTUs had been acquired and that more intensive sampling would likely yield only a few additional OTUs ,33. Howebacteria . The phyNA238270 ; and CP-NA238270  Fig 1)..Cryptoceanalyzed . In thisCryptocercus and Parasphaeria, 5.6 and 5.89 respectively, support a higher diversity community of bacteria similar to other wood or herbivorous-feeding insects [Cryptocercus and Parasphaeria were quantified based on phylogenetic relatedness by unweighted UniFrac. The analyses indicated that the composition of the bacterial communities from the two cockroaches differed significantly (P < 0.03). But, the Venn diagram generated by Mothur v1.36.1 from Cryptocercus and Parasphaeria at a genetic distance of 0.10 showed that six OTUs were shared and were related phylogenetically one to the phyla Spirochaetes (related to Treponema cluster I), two Bacteroidetes (Family Porphyromonadaceae belonging to Dysgonomonas and Parabacteroides genera) and tree Firmicutes   . S1 and Cryptocercus and Parasphaeria fell into three clusters, designated Treponema-termite clusters I, II, and III  Bioproject PRJNA238270 also cluster with pyrotags detected in this work. The second cluster, Treponema-termite cluster II, is much smaller than Treponema-termite cluster I and also much less diverse. It contains only sequences from lower termites and generally they were described in Reticulitermes and Hodotermopsis termites [Parasphaeria grouped with several sequences previously reported as belonging to Treponema-termite cluster II. Several OTUs from Cryptocercus and Parasphaeria grouped with Treponema-termite cluster III that contained Treponema sequences from other cockroaches and from higher termites  and Reticulitermes termite; and second, OTUs detected from Cryptocercus and Parasphaeria clustered with syntrophic Deltaproteobacteria, such as Syntrophobacter spp.  that have been described as a characteristic microbiota in the gut of termites and Cryptocercus [Insects contribute to an enormous diversity of symbiotic relationships. Microbial symbiosis probably played a central role in the evolutionary success of these organisms, allowing their adaptation to ecological niches that are nutritionally deprived and/or unbalanced . The hindgut of insects is persistently colonized by opportunistic and commensal microbiota largely structured by exogenous  and endogenous (gut environment) factors ,21,41. Ttocercus ,41.Cryptocercus metagenomes   [Blattella germanica, is regulated by fecal aggregation agents (pheromones), including volatile carboxylic acids [Comparison of the relative abundance of class taxa among different NA238270  and PRJNNA238270 ) indicatov test) . “Indiviallaxis) . The neoallaxis) . Aggregaic acids . The teric acids –50 or meDictyoptera, the transition from an omnivorous to a wood-feeding lifestyle had a strong impact on the microbial community structure, as observed in Cryptocercus and (lower) termites which included the acquisition of cellulolytic flagellates [Isoptera [Panesthia spp., Salganea spp. and Parasphaeria spp. did not support the characteristic community of gut protists observed in the cockroach Cryptocercus [Periplaneta americana, their cellulose-rich diets have favored high protist numbers , resulting in high cellulase activity. In fact, N. ovalis is responsible for most of the cellulolytic activity of P. americana [Panesthiinae harbor ciliated protists but they are probably not associated with the digestion of wood; rather, they are close related to the genus Nyctotherus, present in other cockroaches [Parasphaeria, while lacking the specific gut flagellates harbored in lower termites and Cryptocercus, many bacterial taxa were found. Of particular interest are Spirochaetes . Acetate produced by the gut microbiota supports up to 100% of the respiratory requirement of termites [nifH) and exhibit nitrogenase activity [In tipennis ,54,59,60tipennis . Spirochtipennis . The maitermites . Spirochactivity . This obBacteroidetes OTUs from Cryptocercus grouped closely with phylotypes previously described from different species of the protist Barbulanympha. The genera Candidatus Symbiothrix, Dysgonomonas, Parabacteroides, Paludibacter and Tannerella were the major genera identified. In Parasphaeria, based on the Silva database, the major genera were Paludibacter, Parabacteroides and Candidatus Symbiothrix. These genera may represent the termite-specific bacterial lineages reported in termites [Bacteroidetes are thought to be specialized in the degradation of complex organic matter, including lignocellulosic compounds [Bacteroidetes were also related to diazotrophic bacteria such as Azobacteroides pseudotrichonympha that provide amino acids and cofactors for the nutrition of the host protist and of the cockroach host [termites ,65. Membompounds . Bacteroach host ,57.Deltaproteobacteria OTUs in Cryptocercus and Parasphaeria hindguts were assigned to the families Desulfobacteriaceae and Desulfovibrionaceae. Both groups are strict anaerobes that are capable of sulfate-reduction. Sulfate-reducing bacteria (SRB) are crucial to the final step of carbon recycling and to the sulfur cycle in anaerobic ecosystems [2-consuming microorganisms), SRB contribute to the anoxic milieu of the gut by producing hydrogen sulfide and by removing oxygen together with hydrogen or low molecular weight organic or reduced sulfur compounds. H2 fluxes almost certainly play a significant role in shaping community structure, as H2 is both widely utilized as a microbial substrate and strongly influences the thermodynamics of the reactions in which it participates [osystems . In addiicipates .Cryptocercus and Parasphaeria; but they shared several bacterial genera found in other termites and cockroaches. Of special interest were several common OTUs detected in the intestinal tract belonging to Spirochaetes, Bacteroidetes and Firmicutes (Clostridia) that could represent a core microbiota essential to hydrolyze plant compounds and to provide nitrogen sources such as amino acids to their host , CP-1, CP-2, CP-3 (Bioproject PRJNA238270) and CP-4 (PRJNA217467); Parasphaeria (this work); Apis mellifera (PRJNA82239) as an out group of the Dictyoptera insect.(TIF)Click here for additional data file.S1 Table(PDF)Click here for additional data file.S2 Table(PDF)Click here for additional data file.


Apparent basicity was verified to be an effective indicator for the selection and optimization of organic amine systems and finally the diisobutylamine + n-octanol system was selected to enhance the carbonation reactions of CO2 in an artificial Ca2+/Mg2+-rich solution. In our experiments, when the volume ratio of insoluble organic phase to aqueous one was 2:1 and the reaction temperature was 28 °C, 92% of Ca2+ and 80% of Mg2+ could be converted to calcium and magnesium carbonate precipitates within 5 min of reaction with the bubbling-in of CO2. The organic amine system could be regenerated by using carbide slag as the regeneration agent and could still show attractive enhancement performances after 7 rounds of carbonation-regeneration experiments. In this way, the CO2 capture and sequestration was realized within one single process, with value-added Ca/Mg carbonates being the byproducts. In view of the vast availability of Ca2+/Mg2+-rich aqueous solutions and the feasible technical coordination with desalination industry, this novel process may have a good application potential in the future.An optimized approach of CO In this way, not only may CO2 be directly transformed into carbonate precipitates and permanently stored as a value-added byproduct1314162 fixation through thermodynamic analyses and kinetic experiments and confirmed that over 90% of the Ca2+ and Mg2+ in seawater could be converted into carbonates on temporal scales of engineering when the pH level of reaction system could be raised steadily by employing something as a pH regulatorOur working group has all along been devoting to the development of a novel CCUS conception, i.e. trying to use Ca2+/Mg2+-rich aqueous system, the equilibrium of CO2 dissolution in water will be broken. As shown in Eq. 3 can extract H+ from water phase into organic phase to form NR3∙H+. The loss of H+ raises the pH of the water phase and triggers the rise of CO32− concentration in the case of sufficient CO2 partial pressure following Eq. 3 and⁄ or MgCO3 are generated as in Eq. In our built-up process, when alkaline amine extractants are added into a Ca2 and its storage as value-added byproducts are realized in just one ordinary-temperature procedure.In particular, the whole process enables operation at a room temperature and there is no additional energy consumption except for the necessary mechanical drive. It means that the capture of CO2+ was very limited in spite of a good precipitation of Ca2+, which was mainly due to the insufficient alkalinity enhancing ability of the amine-diluent combination. It told us that the organic amine system needed optimization in view of the tremendous diversity of combination of insoluble amines and diluents. In this paper, apparent basicity2 fixation experiments were carried out with artificial Ca2+/Mg2+-rich solution in a self-designed continuous experimental setup. The carbonation dynamics of Ca2+and Mg2+, the influence of some factors, as well as the regeneration of diisobutylamine, were all investigated. An overall profile of the CO2 fixation through enhancing carbonation precipitation in Ca2+/Mg2+-rich aqueous solutions was reported.However, when tributylamine was used as the pH regulator and n-butyl alcohol as its diluent in our previous work, the precipitation degree of Mg2+/Mg2+-rich aqueous solutions are widespread and abundant on the earth. For instance, concentrated seawater as a typical one is being increasingly produced by desalination industries as waste in recent years. Its concentrations of Ca2+ and Mg2+ may be twice those of natural seawater, amounting to 0.82 g/L and 2.58 g/L respectively2 through enhancing carbonate precipitation with tremendous application potentials. Because the ions like Na+, K+ and SO42- in seawater were proved not to interfere with the mineralization process in our previous work2 and CaCl2 to prepare a Ca2+ /Mg2+-rich aqueous solution instead of the practical concentrated seawater. The concentrations of MgCl2 and CaCl2 were taken 10.21 g/L and 2.28 g/L respectively. All the reagents used, including the diisobutylamine, n-octonal, MgCl2 and CaCl2, were analytical pure purchased from Sinopharm, China.Ca2 fixation process and shown in 2 and the regeneration of insoluble amine respectively. The inlet of regeneration reactor is connected to the outlet of carbonation reactor, and the regenerated organic amine phase is guided back to the carbonation reactor using a circulating pump. The 1L carbonation reactor has a jacketed glass structure, through which the reaction temperature can be controlled via circulating water provided by a thermostat. And, a stirrer is equipped in the carbonation reactor to keep the sufficient blending of the organic and aqueous phases. All the rest accumulators and collectors are 500 mL instruments with lids. The whole process of CO2 mineralization and amine regeneration can be conducted consecutively in this setup.A set of glass reaction system was specially designed for the CO2+ is twice higher than that of Ca2+ in seawater-based solution, it was a big defect for our previous tributylamine + n-butyl alcohol system that was only able to enhance the precipitation of the later ions. Since there are thousands of different combinations of amine+ alcohol systems for selection, it is possible for us to find a better system which can overcome the limitations in our previous work. However, to carry out the optimization, it would be inefficient and costly to screen the combinations one by one following the way of mineralization experiments in our previous papers. Developing a convenient method or finding a common parameter to reflect the mineralization ability of amine is in urgent need.Since the concentration of Mg+ in essence. Apparent basicity, pKa,B, as a parameter defined by Eyal at alAs shown in Eq. 2 mineralization for our study was first tested. Then, different combinations of amine plus diluent were compared by measuring their apparent basicities under the same operation conditions.Based on the experimental data obtained when we used tributylamine + n-butyl alcohol previously, the reliability of employing apparent basicity to reflect the enhancement abilities of COa,B and Ca2+ mineralization ratio xc when tributylamine + n-butyl alcohol system was employed to enhance CO2 fixation. It can be clearly seen the two parameters have the same trend when the concentration of tributylamine in n-butyl alcohol changes, which means apparent basicity can be used as an effective indicator to screen amines. Moreover, the lower concentration of tributylamine corresponding to higher pKa,B and xc indicates that diluents also play an important role in improving the abilities of tributylamine for H+ extraction and mineralization enhancement.a,B of the two new systems do not rise with the increase of diluent volume like tributylamine + n-butyl alcohol system, but decline slightly instead, which means their relationship is indefinite and might be influenced by the difference of octanol-water partition coefficient. In view of the prominent performance of diisobutylamine + n-octonal system, it was selected as the new mineralization enhancement system in our following experiments and a low dilution ratio of 1:1 was adopted for amine and n-octanol.2+/Mg2+-rich aqueous solution and the insoluble amine + diluent were first added into the carbonation reactor in a certain proportion. The two non-miscible organic and aqueous phases were then well mixed by the stirrer at a speed of 500 rpm. At this moment, a 0.3 L/min CO2 gas stream was guided into the reactor. The reactor was kept at 28 °C and the change of pH was monitored by a pH meter. With the CO2 being bubbled in, the pH of the liquid system declined gradually. When the pH fell to 8.60, the experiment would be terminated.During the carbonation experiments, the Ca2+ and Mg2+ in the aqueous phase were measured with the method of EDTA titration:After a standing of several minutes, the mixed system became stratified steadily. Thereupon, the lower aqueous phase together with the precipitate was guided into collector 5 and the organic phase in the upper layer was guided into the regeneration collector 6. The precipitate was filtered and then dried at 110 °C for 24 h; XRD and SEM were adopted to analyze its properties. The concentrations of CaEDTA is the concentration of EDTA standard solution; V1 is the volume of EDTA standard solution consumed in the titration of Ca2+; V2 is the volume of EDTA standard solution consumed in the titration of Mg2+; V is the volume of subnatant liquid that was used in the titration experiment;2+ and Mg2+ in the initial artificial solution respectively.where, C3⋅H+ to NR3 meant its recovery as the mineralization enhancement agent. The concentrations of H+ in the organic phase before and after regeneration could be titrated by NaOH (0.1 mol/L). Then the regeneration ratio of diisobutylamine can be expressed as:During the regeneration of insoluble amine in the organic phase, carbide slag was taken as the regeneration agent and added into the regeneration reactor at a molar ratio of 1.5:1 for carbide slag vs. acidified amine. The regeneration process lasted about 15 min under stirring at a speed of 500 rpm and 28 °C.The regeneration of diisobutylamine from the form of NR3⋅H+ before and after the regeneration, respectively.2 was bubbled in, the mixed system was only slightly turbid and the pH value kept at about 10.0. With the continuous bubbling-in of CO2, the pH declined from 10.0 to 9.2 within 5 min and to 8.6 within 20 min. Meanwhile, the mixed system was observed to be getting more and more turbid. At some non-fixed intervals, the mixed system was sampled and the corresponding concentrations of Ca2+ and Mg2+ were measured. All the obtained results were shown in In the typical carbonation experiments with diisobutylamine +n-octonal as the enhancement system, the organic phase and aqueous phase were mixed at the volume ratio of 2:1 and the reactions were carried out at 28 °C. Before CO2+ and Mg2+ took a declining trend with the increase of reaction time. The concentration of Ca2+ dropped dramatically within 4 min and almost kept unchanged in the following period. There was a total drop of about 98% finally. The decline of the concentration of Mg2+ was not as sharp and quick as that of Ca2+ but it also had a drop of 91% within 5 min and changed unnoticeably later. It meant that most of the Ca2+ and Mg2+ could be precipitated in our experiments by using the diisobutylamine + n-octanol system as the pH regulator. The vast-majority precipitation of Mg2+ in this experiment, which was not obtained in our previous work while using tributylamine + n-butyl alcohol, indicated that the carbonation enhancement method here was more suitable for Mg2+-rich aqueous sources and had much better application potentials than before.It can be clearly noticed in 2+ and Mg2+ should be caused by their distinct solubility product constants, Ksp, as well as their different initial concentrations. The Ksp of MgCO3 is 1.15 × 10−5 at 298 K, while that of CaCO3 is 4.95 × 10–9,3 has a much higher tendency of precipitation forming and will be sure to precipitate in priority at a certain concentration of CO32−.The different precipitation rate of Ca2+ and Mg2+ at different phase ratios. When the phase ratio increased from 1.3:1 to 3:1, the precipitation percentage of Ca2+ did not vary much and all through remained at over 90%. However, the precipitation percentage of Mg2+ was only 46% at the phase ratio of 1.3:1 and yet increased to 80% at 2:1. While, there was very limited further growth, only from 80% to 83%, when the phase ratio changed from 2:1 to 3:1.The reason for this should be that the increasing phase ratio could enhance the extraction of H+ from the aqueous phase and thereupon provide more drives for the rise of CO32- concentration which triggered the precipitation of Mg2+. The less influence on Ca2+ precipitation should also be owing to the much smaller Ksp of CaCO3 than MgCO3. Since the effect of mineralization enhancement was not prominent at a phase ratio of higher than 2:1, the phase ratio can be fixed at 2:1 in practical processes.The volume ratio of organic and aqueous phases, i.e. phase ratio, was proved to affect the carbonation performance greatly in our previous experiments2+ and Mg2+ at a phase ratio of 2:1 under different temperatures. It can be found that, when the reaction temperature rose from 8 °C to 38 °C,the carbonation percentages of both Ca2+ and Mg2+ increased to some extent; yet, the increase for Ca2+ was very slight while that for Mg2+ was more noticeable, from 72% to 84%. It meant that the increase of temperature from 8 °C to 38 °C could be conducive to the carbonation reactions for the diisobutylamine + n-octanol system. In our previous work based on tributylamine + n-butyl alcohol system, however, the increase of temperature from 10 °C to 40 °C had sharply lowered the mineralization ratio of Ca2+. Accordingly, the diisobutylamine + n-octanol system has substantial advantages from multiple angles. The favorableness of higher temperature makes the process suitable to directly capture the CO2 in some exhaust gases like the flue gases from fossil-fuel power plants.The influence of temperature on the carbonation process was also tested. 0.92Ca0.08CO3·3H2O, MgCO3·nH2O and CaCO3. These results confirmed that the carbonation reactions entirely met our expectations. Thus, the diisobutylamine is an effective candidate in enhancing the precipitation of Ca2+ and Mg2+ in their specific aqueous solutions.For the obtained precipitate product, which took the form of white powder after filtering and drying, XRD and SEM were adopted to determine its mineral compositions and properties. 2+ were much more than that of Ca2+, it is reasonable that the rod-shaped MgCO3 is dominant. In addition, it can be found that the crystal forms are similar in the three SEM figures, which means that the change of reaction temperature and whether or not the amine experienced regeneration had little impact on the formation of carbonate precipitate.In addition, since the carbonate products are in excellent state of particle sizes, color appearance and composition stability, they may have vast forms of application in industrial fields. For instance, there is even no need for further disposal when they are used as filling materials in paper, printing, rubber, polymer, etc.4H9)2·H+, so the regeneration of the amine should be a process of converting NH(C4H9)2·H+ back to NH(C4H9)2. The regeneration can be achieved by the addition of some basic substances, such as NaOH, Ca(OH)2, ammonia water, etc, or through directly heating. A kind of basic industrial waste, carbide slag, was used to regenerate NH(C4H9)2 here. The performances of the regenerated organic phase were tested in different experimental cycles of carbonation enhancement.The regeneration performance of the pH regulator, namely the insoluble organic phase, determines its operation life and industrial application prospect. During the mineralization process, the insoluble diisobutylamine extracts hydrogen ions from the aqueous phase into the organic phase to form NH The CO2 capture and sequestration can be realized within one single process and there is no need for the CO2 separation, liquification and transportation. The transformation from gaseous CO2 to solid carbonates can be completed at room temperatures and within a period as short as several minutes. 2) The precipitate products are stable calcium and magnesium carbonates, which have vast application potentials in industrial fields owing to their fine particle sizes, white color appearance and chemical composition stability. 3) The Ca2+/Mg2+-rich aqueous solutions are widely distributed and abundant in both categories and quantities, as provides good implementation possibilities for this novel conception. For instance, concentrated seawater or brine effluents, which are usually discharged as waste in desalination industry, can extend their value chains through CO2 fixation; meanwhile, the removal of Ca2+ and Mg2+ from these solutions may trigger lower scaling and lead to higher ratios of fresh water production.The CO2 mineralization process may also be built up by enhancing the dissolution of silicate minerals and the carbonation of CO2Further work is just being focused on another method of regeneration for the insoluble amine, where calcium and/or magnesium silicates are tested as the regeneration agent. If it works well, a novel quick COHow to cite this article: Wang, W. et al. Experiment and Optimization for Simultaneous Carbonation of Ca2+ and Mg2+ in A Two-phase System of Insoluble Diisobutylamine and Aqueous Solution. Sci. Rep. 5, 10862; doi: 10.1038/srep10862 (2015).


This paper presents a novel secure and robust steganographic technique in the compressed video domain namely embedding-based byte differencing (EBBD). Unlike most of the current video steganographic techniques which take into account only the intra frames for data embedding, the proposed EBBD technique aims to hide information in both intra and inter frames. The information is embedded into a compressed video by simultaneously manipulating the quantized AC coefficients (AC-QTCs) of luminance components of the frames during MPEG-2 encoding process. Later, during the decoding process, the embedded information can be detected and extracted completely. Furthermore, the EBBD basically deals with two security concepts: data encryption and data concealing. Hence, during the embedding process, secret data is encrypted using the simplified data encryption standard (S-DES) algorithm to provide better security to the implemented system. The security of the method lies in selecting candidate AC-QTCs within each non-overlapping 8 × 8 sub-block using a pseudo random key. Basic performance of this steganographic technique verified through experiments on various existing MPEG-2 encoded videos over a wide range of embedded payload rates. Overall, the experimental results verify the excellent performance of the proposed EBBD with a better trade-off in terms of imperceptibility and payload, as compared with previous techniques while at the same time ensuring minimal bitrate increase and negligible degradation of PSNR values. During the past decade, the rapid advance of Internet, storage, digital communication technology, multimedia and network bandwidths technologies has enabled users to send digital data over network suitably. It is now possible to stream high quality video and to watch video online. The Internet and other digital networks are means for freely and widely distributing high fidelity of digital media . HoweverMany researchers, companies, and organizations continue to find novel security measures that can provide better protection for secret information in terms of privacy, integrity, or authentication from being detected during transmission. Numerous research efforts in cryptography have been put forward, such as Data Encryption Standard (DES) , Rivest However, such methods are not suitable for encrypting digital images without modification due to two strong reasons: characteristics of digital images and difficulties of distributing keys . MoreoveData hiding techniques have been considered widely in various fields such as covert communication, copyright protection, broadcast monitoring and military communications. Steganography is defined as the art of imperceptibly hiding confidential information in such a way that no one realizes it except the sender and the authorized recipient. It is also known as ‘covert writing’ which includes methods of transmitting secret messages through inoffensive cover mediums in such a manner that the survival of the embedded messages is undetectable.Visual data such as digital videos has become a popular multimedia content for both online and offline environments and therefore large video clips mean larger volumes of data can be embedded in video files but they require a large processing capacity or transmission bandwidth. Hence, they are often required to be converted in order to adapt to several channel capacities  as well as end user's terminal capabilities .Data hiding can be carried out in different domains. For instance, data embedded in spatial domain may be lost because of the lossy stage (quantization step) of the underlying video codec while in the frequency domain; data hiding is performed in the transformed coefficients where it survives the quantization loss but this may come at the cost of lower imperceptibility . Some reData embedding is performed in a block by block basis utilizing the length of zero-run coding value of AC-QTCs as a host signal. In this method, data bits are embedded into I-, P- and B-frames and the data payload is controlled by adjusting a certain parameters thereby achieving low embedding capacity. The results demonstrated that the payload size in I- and P-frames is much larger than of B-frames . Xu et aFor low bitrate increase due to data embedding, Wong et al.  proposedWang et al. proposed a data hiding scheme to embed information into MVs of P-frame of the compressed video. In this scheme, the embedded information is extracted from every region of utilized MVs during the process of the decoder. The results of the scheme demonstrated that there was little impact on both video quality and the bit rate increase where an average increase of 4% in the video bit rate has been reported . To compTo enlarge the payload rate of the embedded data, Sherly and Amritha proposed a compressed video steganographic scheme namely tri-way pixel-value differencing (TPVD).The TPVD scheme operations are executed entirely in the compressed domain of MPEG standard. The scheme is tested on I-frame with maximum scene change and on P- and B-frames with maximum magnitude of MVs. Experimental results demonstrate that intra frames yields the highest payload and imperceptibility compared to inter frames (i.e. P- and B-frames) . HoweverAli et al proposed compressed video steganographic scheme based on the concept of differential expansion (DE). The scheme utilized both luminance and the chrominance components within the intra pulse code modulation macroblocks of the P-frames of the H.264/AVC. It was tested for a variety of video sequences and compared to other techniques having similar concept. The results demonstrated that the proposed scheme provides better performance in terms of embedding capacity, lower bitrate increase compared to other techniques and negligible degradation of video quality .Comparative Analysis of various data hiding techniques in Compressed Video Domain was presented by Tarik et al. . Data hiEven though the above-mentioned data hiding schemes generally produce an acceptable degree of video quality regardless of their applications and data carrier in use, the overall imperceptibility, of the modified video (i.e. stego video) is always limited to embed data payload. This is a critical drawback because these data hiding technologies cannot be utilized in applications where degradation in the quality of video sequences is not allowable. To solve this problem, we propose a novel data hiding technique (i.e. Embedding-Based Byte Differencing (EBBD)) in the compressed video domain that completely preserves the video quality based on the main steganography issues, such as imperceptibility, embedding capacity, and level of security and archives better trade-off between these issues.Due to the huge amount of the data present in motion video, the MPEG-2 is designed as a compressed digital video standard which removes both the temporal and spatial redundancy. Further reduction of the redundancy data is achieved by run length and variable length coding. The MPEG-2 is split into hierarchy layers startly with video sequence layer and endly with block layer. The video sequence layer consists of a number of group of pictures (GOPs). The frames of each GOP in this study are independently encoded and decoded. Usually, the GOP structure consists of three types of pictures: intra-frame (I-frame), bidirectional-frame (B-frame), and the predictive-frame (P-frame) and the GOP may take different length .Generally, the maximum GOP length depends on the specifications of the playback device whereas the minimum GOP length depends on the GOP pattern. Although small GOP patterns with a short GOP length do not compress the data rate as effectively as large GOP patterns with a long GOP length, it works better with videos that have quick movements. In other words, longer GOP lengths encode video more efficiently by reducing the number of intra frames.However, a long GOP is less desirable for short-duration effects, such as fast transitions or quick camera pans. Furthermore, a long GOP means that several inter frames (i.e. B-frames) are used between intra frame intervals, providing high image quality for a given data rate but requiring a long time to decompress. This result happens because B-frames within the GOP are reliant on frames that may be reliant on other frames in addition to the P-frames that are dependent on the I-frames for referencing.For most encoders, the default GOP structure is a 12-frame GOP, which is IBBPBBPBBPBB before the repeat. However, if the video is detailed or fast moving, then it can be shortened to a six-frame GOP or less, especially in the case of real-time transmission of MPEG video in which the GOP structure is typically composed of six frames patterned as IBBPBB. Consequently, the process of adjustment in the GOP structure may result into either increases or decreases the resolution, encoding and decoding time and compression performance.M number of slices where each slice is further broken up into N numbers of macro-blocks (MBs) and each MB has four 8 × 8 luminance blocks (Y) and two chrominance blocks (U and V). The content of each block is a 2-D DCT coefficient that is quantized using uniform scalar quantizer (USQ) specified by a fixed quantization table which is then variable length coded (VLC). Given that Y-component (brightness) blocks are located in an unaffected channel; these are used as host blocks to minimize the color distortion in the embedded video.Therefore, a short GOP structure with the length of six and display order of IBBPBB is chosen to be used for implementing the proposed video steganography system. Each of these pictures is broken up into This study devised a complete MPEG-2 video data hiding scheme. Data are embedded in the luminance space during compression of a CIF file. Considering the standard color space of video and low correlation among three color components, YCbCr color space is used in the proposed video data hiding scheme. Conventional videos consist of a number of GOPs; in this paper, the GOP structure consists of six pictures in display order "IBBPBB,". The frames of each GOP are independently encoded and decoded.Each frame is divided into N numbers of slices consisting of M macro-blocks, and each macro-block has four 8x8 luminance blocks (Y) and two chrominance blocks (U and V). The 2-D DCT is applied to each non-overlapped 8×8 block in 64 DCT coefficients. These coefficients are then quantized using uniform scalar quantizer, specified by a fixed quantization table, zigzag scanned, and VLC coded. Since the Y-components (brightness) blocks are on an unaffected channel, they are used as host blocks to minimize the color distortion in the embedded video.The alteration of a single coefficient affects the entire 64 pixels block, but because the change works in the compressed domain rather than the spatial domain, there will be less visual artifacts in the reconstructed frame if those coefficients are handled carefully. For the purpose of avoiding creating step effects in block coefficients that increase the distortion to the stego-signal, the QTCs should be modified as little as possible. Furthermore, the AC-QTCs become zeroes mostly after quantization. These zeroes are usually sensitive of embedding and the embedding capacity of the compressed host signal. Indeed, a high percentage modification in AC coefficients will certainly lead to significant distortion in the generated stego-signal. Therefore, an optimal balance between degradation and embedding capability should be determined.Fx, let Bq refer to each 2D-QTCs 8×8 block and Bz is the output of the zigzag scan operation, Bz = {C1,…,C64}, where C1 is the DC coefficient and C2,…,C64 are the AC coefficients. Therefore, a subset of coefficients is extracted from Bz containing 63 AC coefficients is denote as Bs, m < 64 and are considered suitable coefficients for data hiding. Since the frame size is 352 x 288 pixels, this resulting in a total of 1584 of 8 x 8 DCT blocks, TBs = 1584 where TBs is computed asTo embed data bits into MPEG-2 compressed video, an ordinary presentation mechanism namely, HCSM is proposed in order to select the proper AC-QTCs as carrier. For every desired frame, Bs subsets are then arranged in 2-D arrays denoted as Bs. Hence, the Bs in the modified array, These The data path and flowchart of the data embedding process using the EBBD steganographic algorithm in the compressed MPEG-2 domain is shown in Bshuf (j), j = , where h is the total number of selected blocks is computed using This work basically deals with two security concepts for the embedded data from being detected: Data are encrypted and the randomness of the selected host AC- QTCs. The concept of encrypting data has already been achieved by using S-DES technique . The ranThese blocks are then randomly flipped by 0°, 90°, 180°, 270°, and 360° as shown in By contrast, asymmetric algorithms are computationally more expensive and time consuming, apart from having significant practical difficulties in securely distributing a symmetric key. Since both symmetric and asymmetric algorithms are used for secret communication but not for concealing communication and to avoid an expensive processes and time-consuming, the S-DES, regardless of the use of such algorithm to encrypt confidential data, has been used as further method to provide an additional layer of security to the embedded data by encrypting the secret key itself that is used to pseudorandomly shuffle the coefficients in each segmented block of coefficients. Thus, it is virtually impossible for unauthorized people who know the algorithm to pirate the hidden information, without knowledge of the encryption key.Bs) in Hence, shuffling implies that the AC- QTCs of each row (BC(i), where i is the block index, by running every two rows by two rows respectively from BC(i) is the basic structure in the embedding scheme in which the four coefficients in each block are denoted as Cx,y), is suitable or not for data embedding. The recommended choice for the key controller parameter value is, when the Cx,y) can be expressed asThe technique determines the QTCs that can be used for embedding using two different branch conditions in order to avoid undesired visual distortion in a stego-signal. The first condition determines the embeddable and non-embeddable blocks of quantised DCT coefficients while the second condition identifies the coefficients within the determined blocks to be used for embedding. The SR), R =  3 > SR > −3, because a large coefficient value will degrade the quality of the stego-frame. Thus, only possible coefficients selected within the allowable range in this technique guarantee the distortion would be unnoticeable to the human eye.Thus, the maximum probabilities of embedding data bits are only in three coefficients; that is, only three of four AC- QTCs values can be selected to embed data. Each value of these coefficients is located in selected coefficients range , β1 = (01), β2 = (10), and β3 = (11). To identify the coefficients within the determined blocks to be used for embedding, each of the embeddable block is sequential ranked denoted by, φ) is produced to decide which coefficients are selected for future use. The XOR operator, which is performed between the key controller value Cx,y), the following three cases are considered according to the value of φ to identify host coefficients.In this category  are selected if φ = 0.Case 1: The coefficients mapped as  are selected if φ = 1.Case 2: The coefficients mapped as  are selected if φ = 2.Case 3: The coefficients mapped as (T) are broken up into a series of blocks, (εT(i)), i =1,…,R where R is total number of secret data blocks and εT(i) ∈ {0,1}. Each block consists of two bits. These bits are transformed individually into decimal value denoted by ε(D), ε(D+1) where D represents the location of the bit in the secret data block. The proposed scheme permits embedding two bits into two coefficients within BC(i) by determining the difference between the value of key controller parameter and each transformed secret data block. This difference is considered as the modified coefficient value and replaces the original coefficient value that was selected according to φ. The equation below, which is built up in accordance with the HVS features to guarantee the stego-signal still preserves good quality, confirms the probability of the information embedded in the corresponding coefficient.The bytes of the encrypted secret data (εεT(i) bits; that is, the coefficient values are changed to the absolute value of their new difference. The embedding scheme changes some of the coefficient values closer to zero and some values further. Accordingly, the average bit rate remains more or less the same. For simplicity, according to εT(i), two possible differences are determined through the following equations:The two corresponding coefficients are expected to carry Therefore, the modified block BC(i). According to experiments, a choice of two AC- QTCs can provide excellent visual quality. In addition, three bits of data can also be hidden in three AC coefficients by modifying the technique. As can be seen from The advantage of this strategy is that all of the AC- QTCs with zero values can be used for embedding data in the compressed video domain while maintaining high perceptual quality. di). Since the maximum probabilities of embedding data bits is only into three coefficients, only three out of four different coefficients are identified within a selected block BC(i) using Eqs  is related to the total number of modified coefficients. The obtained two difference values of εD)( and εD+1) block. Finally, after all the embedded bits blocks are retrieved, the bytes of the encrypted secret data are built back in εT and every byte is converted to represent a character to get the Ciphertext.To retrieve the embedded data, the modified video is parsed in the exact same order as a data embedder does. The flowchart for data extraction is shown in sing Eqs  and 7)..di). SinThe system is simulated using MATLAB version 7.17.0.739. To facilitate our investigation, the reference implementation of MPEG-2 is used and applied with EBBD steganographic technique on 150 frames of each of the six widely known raw YUV video sequences in CIF format with 30fps and a resolution in pixels of 352 × 288 (width × height). All these video sequences are filmed using professional and high-end equipment to ensure that the reference sequences are alteration free. Furthermore, these sequences represent different combinations of motion and are classified into three classes based on their motion activities. The video sequences "Miss America" and "Suzie" contain still background with motion in the foreground and with limited motion in certain frames and such videos are classified as Slow-Motion Videos (SM-V). "Silent" and "Foreman" contain camera motion where the subject moves his/her entire upper body frequently twice toward the end of the video and are classified as Intermediate-Motion videos (IM-V).The video sequences "Football" and "Stefan" contain camera panning and zooming along with considerable object motion and texture in the background. Therefore, a variation in motion of the background as well as the subject is observed, thereby, such videos are classified as Fast-Motion Videos (FM-V). Thus, the behaviour of the proposed system is analysed under various input characteristics. For the embedding payload, up to 4 KB of data is embedded and analysed on each of I-, P- and first B-frames of each of the 25 selected GOPs of the compressed video sequences.Vs is the source video file size, VP is the processed video file sizeThe performance evaluation of the EBBD is done by examining the technique in terms of data hiding effects on the file size, invisibility and robustness. The performance of the proposed technique method is measured by comparing with existing steganographic techniques. Compression ratio (CR) has been identified as the number of bits of the original video divided by the number of bits used to represent the compressed video and is given in Eq . Peak siWhere MSE is determined through the following equation:Fm,n is the original frame, and M ×N is the size of the video frame. However, PSNR does not perfectly correlate with a perceived visual quality due to the non-linear behaviour of the human visual system (HVS).The mean square error (MSE) metric measures the difference between the reference and processed data signals. μ represents the mean intensity of the Fm,n and CS1 and CS2 are constants.Consequently, structural similarity index metric (SSIM)  is consiRobustness is measured by the bit error rate (BER) of the extracted embedded data as a function of the amount of distortion introduced by a given manipulation to determine the reliability of the extracted data. BER is defined as the ratio of incorrectly extracted data bits by the decoder side to the total number of embedded bits. BER is 0.00 for most extracted data, except for the exchange attack where it is larger. The robustness of the embedding methods is given in Eq (17)CRcover and CRstego are the compression ratios generated from the MPEG-2 cover video and stego MPEG-2 video, respectively. VFScover and VFSstego are the video file sizes of the MPEG-2 cover video and stego MPEG-2 video, respectively.In order to evaluate the performance of the EBBD, data payload of 32768 bits has been tested on the selected video sequences. The original video streams are obtained by the MPEG-2 implemented software, and the embedding schemes are integrated with the MPEG-2 coder. All selected video sequences are encoded with MPEG-2, with their resolutions of 352×288 and 30fps. The evaluation was based on a sample of 25 GOP and picture ratio of I:P:B = 1:1:4 from each video (i.e. 6×25 = 150 frames).The following terminology is used in this section:. VFSstego increase and CRstego reduction expressed in percentages is tabulated in This section discusses the influence of embedding data on SM-V, IM-V, and FM-V MPEG-2 sequences when data payload of 32768 bits is embedded using EBBD. The recorded results are tabulated in VFSstego and CRstego is less for FM-V sequences followed by IM-V and SM-V sequences in all embedding cases of the frame type because the magnitude of the AC-QTCs are not significantly altered by the embedded data that reduce the code length of the VLC. Hence, FM-V sequences are more applicable for data embedding because of the texture and high amount of motion within these sequences.As indicated in the VFSstego increased considerably. Such technique has a minimal modification in the AC-QTCs with magnitude zero because the data are mostly hidden in the bit-planes for the low and medium frequency components of the AC-QTCs.The VFSstego is mostly due to the use of the medium and high frequency components of the AC-QTCs. However, the EBBD scheme preserves the quality of the video sequence at the expense of the VFSstego increment.Although the TPVD utilizes fewer QTCs, it has significantly altered these selected AC-QTCs, particularly for AC-QTCs with a magnitude of zero because a large number of data bits are embedded by changing the difference between the values of the selected coefficients. For the EBBD technique, regardless of the number of utilized blocks, the increase in the VFSstego increased with the BPCS technique as the reference; the average increase of VFSstego is 2.23%, 3.69%, 2.23%, and 0.95% for EBBD, PVD, EPVD, and TPVD, respectively, for the data embedded to the SM-V sequences case scenario. For the scenario of embedding data in IM-V sequences, the VFSstego increase up to 0.83%, 2.38%, 0.56%, and 1.4% for EBBD, PVD, EPVD, and TPVD, respectively, and to 0.56%, 0.98%, 0.00%, and 0.56%, respectively, when the data are hidden in FM-V sequences. The level of alteration in the VFSstego is basically based on the number of selected blocks, frequency component type , and the amount of data bits embedded in these blocks. According to the results, this effect can be almost ignored especially when the data are embedded into IM-V and FM-V sequences. The relationship between CRstego and VFSstego is non-linear and exponential. Thus, the CRstego decreases as the VFSstego increases, and vice versa.The EPVD performs better than its original version (PVD) because of the modification applied on the original PVD that always makes the absolute difference almost equal to the original two coefficient blocks, particularly for AC-QTCs with a magnitude of zero. However, EPVD utilizes more QTCs blocks compared with the PVD. Using the We evaluate the imperceptibility of the EBBD using PSNR and SSIM quality metrics. The secret data are hidden within the luminance component of the video sequence. Hence, the quality metrics are used to evaluate the quality of the stego video over the luminance channel only of the stego video (compressed + embedded) with respect to original video (compressed only). Figs EPVD outperforms the PVD scheme. This finding implies that modifications applied on the original PVD, which makes the absolute difference as close to the original two-coefficient block as possible, especially for AC-QTCs with a zero magnitude, thereby successfully reducing the degradation in the video quality caused by the PVD scheme. However, these modifications preserve the quality of the video at the expense of embedding payload. To evaluate stego video quality, SSIM metric, which is believed to be more consistent with HVS perception than previous metrics, is employed to evaluate the perceptual quality of each test video sequence. According to its definition, a larger SSIM value corresponds to higher visual quality. To demonstrate the quality performance for video sequences individually, On the frame basis, among the steganographic schemes, EBBD generates better-quality stego videos with higher Y-SSIM values compared with other schemes (less reduction in Y-SSIM), while PVD generates the worst quality stego videos with lower Y-SSIM values. EBBD demonstrates better performance. An average decrease in Y-SSIM is 0.050, 0.049, and 0.051 dB for I-, B-, and P-frames, respectively, is observed for EBBD, while a similar average reduction of 0.099 dB for I-, B-, and P-frames is observed for PVD. BPCS performs worse than EBBD, followed by EPVD, and TPVD. For I-, B-, and P-frames, the average decrease is 0.053, 0.051, and 0.052 dB, respectively, for BPCS, 0.058, 0.056, and 0.057 dB, respectively, for EPVD, and 0.091, 0.075, and 0.081 dB, respectively, for TPVD.On a video category basis, among the different data embedding schemes, EBBD performs best, having a minimum average decrease in video quality for all types of video categories . Samples of the SSIM error maps of the Y-components of the intra stego frame within the third GOP for the “Suzie,” “Silent,” and “Football” are given in Figs Maps are significant for the BPCS scheme especially for the top left side of the frames, as shown in Figs The subjective evaluation of the stego videos is based on determining the difference in quality between the coded versions with MPEG-2 codec without data embedding, and stego MPEG-2 coded versions generated using different embedding techniques. Similar observations are provided to the same class videos for SM-V, IM-V and FM-V, respectively. To evaluate the visual quality performances of stego video sequences generated from different embedding techniques, instead of being concentrated in a relatively small area of the frame, for a given scene, backgrounds of video frames can be considered.Among the embedding schemes, EBBD clearly performs better. No perceivable degradation in the visual quality in the case of intra and inter frames exist compared with corresponding MPEG-2 coded frames without data embedding for all of the SM-V, IM-V and FM-V video sequences. This finding implies that increasing the embedded payload may be possible using the proposed EBBD technique before any perceivable effect occurs on the characteristics of the encoded video.Using BPCS, small encircled white artifacts are found around the left side of the person and the person’s facial hair, and more artifacts are visible in white and black spots on the left for the SM-V video sequences. However, such artifacts slightly appeared in the IM-V video sequences, except those artifacts around the person’s face, which is considerably visible because of the background color. Blotch artifacts are more apparent around the players for the "Football" and even in "Stefan" sequences.The strongly amplified difference between the stego frames generated using PVD and the corresponding coded frames is observed for each video within each video category sequences. Artifacts can be observed in the stego frames because of data embedding especially for the backgrounds of video frames. Artifacts are visible as blurred edges in some blocks and blotches. Blotches appear because of the significant change in luminance and drift effect. However, these artifacts are hardly found in the same stego frames generated using the proposed EPVD for all of the SM-V, IM-V and FM-V video sequences. This finding implies that modifications applied to the original PVD, which makes the absolute difference as close as possible to the original two coefficient block, especially for AC-QTCs with magnitude zero, successfully reduces the artifacts caused by PVD in the video. The visual quality of intra frames of the same class videos for SM-V, IM-V and FM-V are severely degraded. In the stego frame, fewer AC-QTCs were employed compared with that in the PVD scheme, but it was heavily modified. Therefore, the noise is due to the introduction of new QTCs because of serious conversion especially for zero AC-QTCs.A new secured video steganography technique namely EBBD has been proposed in the compressed domain that has the capability to preserve the video quality. The EBBD technique can embed certain of data and compress video to MPEG-2 at the same time. In addition, the EBBD technique has been introduced to improve the embedding efficiency by trading off with payload. The technique embeds the encrypted data bits in the AC-QTCs for different types of frames. Selection of appropriate QTCs blocks, the embedding algorithm, and use of a pseudo random key enhanced security of the proposed technique without adversely affecting the overall file size, SSIM and the PSNR of the video bitstream. The validation of the technique was performed by a series of experiments that proved the ability of the model to embed encrypted hidden data into luminance components for both intra and inter-frames for a variety MPEG-2 compressed video sequences and was compared with five recently reported data hiding schemes , 21, 22 The success of the technique also highlights the usefulness of experimental approach in solving the problem of secure communication. Although data to be embedded has been encrypted using S-DES algorithm, for additional layer of security, an encryption key based shuffling is used to pseudo-randomly shuffle the host coefficients in each candidate block within a selected frame respectively. As result, it is virtually impossible for unauthorized people who know the algorithm to pirate the hidden information, without knowledge of the encryption key. In addition, the robustness of the EBBD has been evaluated against compression attack and it is found that it can resist such manipulation with robustness percentage close to100% on average.