Due to the rapid development of quantum computing technology, encryption systems based on computational complexity are facing serious threats. Based on the fundamental theorem of quantum mechanics, continuous-variable quantum key distribution (CVQKD) has the property of physical absolute security and can effectively overcome the dependence of the current encryption system on the computational complexity. In this paper, we construct the spatially coupled (SC)-low-density parity-check (LDPC) codes and quasi-cyclic (QC)-LDPC codes by adopting the parity-check matrices of LDPC codes in the Advanced Television Systems Committee (ATSC) 3.0 standard as base matrices and introduce these codes for information reconciliation in the CVQKD system in order to improve the performance of reconciliation efficiency, and then make further improvements to final secret key rate and transmission distance. Simulation results show that the proposed LDPC codes can achieve reconciliation efficiency of higher than 0.96. Moreover, we can obtain a high final secret key rate and a long transmission distance through using our proposed LDPC codes for information reconciliation. Quantum key distribution (QKD) ,2,3 is oIn DVQKD, the polarization or phase of weak coherent states is used as the carrier of information and the quantum states received are measured by using a single-photon detector. In continuous-variable quantum key distribution (CVQKD), the amplitudes and phase quadratures of Gaussian-modulated coherent states are considered to be the carriers of information and the receiver utilizes homodyne or heterodyne detection techniques to measure the transmitted quantum states . For a CR is the adopted rate of low-density parity-check (LDPC) codes and s. IK in Equation -LDPC codes and QC-LDPC codes based on ATSC LDPC codes. The structure of QC-LDPC codes is convenient for memory storage and has low encoding/decoging complexity, while the variable nodes at the boundary of SC-LDPC codes are more likely to be successfully decoded. Due to the special structures of QC-LDPC codes and SC-LDPC codes, we can further improve the reconciliation efficiency by constructing QC-LDPC codes and SC-LDPC codes based on ATSC LDPC codes and then employ these codes to the CVQKD system. The numerical results show that the proposed codes have higher reconciliation efficiency than the original codes, which can improve the performance of secret key rate and transmission distance.This paper is organized as follows. In In this section, we first briefly present the multidimensional reconciliation protocol in the CVQKD system, and then introduce ATSC LDPC codes, which will be used to construct error-correcting codes for information reconciliation part.X and sends it to Bob through a quantum channel to get sequence Y. Then, Alice and Bob divide X and Y into groups; each group consists of n elements, where n denotes the dimension of multidimensional reconciliation. Technically, we mainly adopt 8-dimensional reconciliation in the CVQKD system since it outperforms the other dimensions in reconciliation Alice’s side prepares Gaussian sequence n=1,2,4) .X and Y into x and y, respectively, where x = Alice and Bob normalize u is randomly generated, and then sequence e is generated by sequence u through LDPC encoding. In order to get sequence e used in the multidimensional reconciliation, e needs to be converted to a binary spherical sequence A binary sequence y and sequence e, where H is the parity-check matrix of LDPC code. Subsequently, Bob transmits the rotation function and syndrome to Alice through a classical channel.Bob’s side begins to calculate rotation function found in ; H is thx to c, i.e., c into sequence Alice receives the rotation function and maps her Gaussian sequence In this work, we adopt reverse reconciliation scheme due to its longer transmission distance. The schematic diagram of multidimensional reconciliation protocol is shown in We can greatly improve the final secret key rate and extend the safety distance of quantum communication by combining LDPC codes and multidimensional reconciliation. From Equation , we can The LDPC codes in the ATSC 3.0 standard adopt two different lengths, commonly referred to as short codes  and long codes . There are two different coding structures for each code length, i.e., irregular repeat accumulate (IRA) and MET. For each code rate, the coding structure is determined by its bit error rate (BER) and FER performance over binary phase-shift keying/quadrature phase-shift keying modulation. The IRA structure shows better performance at high code rates while the MET structure shows better performance at low code rates . The strH, whose size is A of size D of size A part has a D part has a dual-diagonal structure.As shown in AD] in the upper left corner of the parity-check matrix has the IRA structure shown in Z part is a zero matrix of size I part is an identity matrix of size BC] is a The parity-check matrix of the MET-structured LDPC code is shown in I can be obtained in parallel and encoding latency can be correspondingly decreased  part which is cascaded with the IRA structure and the all-zero part Z. Each element in the Z part will be replaced by the For convenience of presentation, we divide the parity-check matrix of MET-structured LDPC code into three parts, namely, an IRA structure which is embedded in the MET structure, a [BCI] part can be extended to QC-LDPC code in a same manner as shown in Since the IRA structure is embedded in MET structure, the [L is 3; the parameter p is set to a random integer from 0 to 2. Each 0 and 1 of the base matrix will be replaced by all-zero matrix and random CPM of size For a simple example, we consider constructing the base matrix as shown in Equation ,(12)Hb′It is easy to see that the girth of base matrix in Equation  is only Technically, the error-correcting performance of our proposed code is related to its corresponding base matrix. In this work, we adopt the parity-check matrix of ATSC 3.0 standard LDPC code as the base matrix due to its excellent error-correcting performance, which plays a vital role in assisting two parties to obtain symmetrical secret keys in the information reconciliation process. Furthermore, our proposed LDPC codes based on ATSC LDPC codes can achieve a very high reconciliation efficiency under a very low FER, which will be verified in the next section.n is set to 8.In this section, we analyze the performance of proposed LDPC codes in terms of reconciliation efficiency As can be seen from According to Equation , it is oAs shown in In conclusion, we combined a multidimensional reconciliation protocol with our proposed LDPC codes based on ATSC LDPC codes. Generally, for a CVQKD system, we needed to improve the reconciliation efficiency in order to achieve higher performances of secret key rate and transmission distance. In this paper, our aim was to maximize reconciliation efficiency


Background: Risk behaviors for young adults such as alcohol use are associated with increased risk of morbidity and mortality. Patterns of risk behavior may be genetically determined and vary between genders. Previous studies in both young adults and heavy drinking adult samples have demonstrated that some genotypes, such as OPRM1 A118G, COMT Val158Met and DRD2 Taq1A and DRD4 C52IT, may predict addictive behaviors including alcohol consumption and impulsivity, although results have been mixed.Methods: This study aimed to investigate the predictive relationship of these four single nucleotide polymorphisms (SNPs) prospectively on student patterns of drinking using a micro-longitudinal daily diary design in a sample of 628 young adults ages 18–25 of predominantly of European ethnicity. Linear mixed models were used to examine the effect of SNPs on the number of drinks per drinking session with gender as a moderating variable.Results: There were no main effects for genotype on alcohol consumption, nor for gender × genotype for any of the SNPs. There was a trend for an effect of the DRD2 Taq1A on the number of drinks per drinking day and for the interaction of gender and DRD2 Taq1A on the number of drinks per drinking day.Conclusion: These findings suggest that the DRD2 Taq1A, OPRM1 A118G, DRD4 C521T, or COMT Val158Met polymorphisms, are not associated with alcohol consumption in young adults, although there may be a relationship between DRD2 Taq1A and alcohol consumption in young adult males. DRD2 Taq1A, DRD4 C521T, COMT Val158Met, and OPRM1 A118G.Risk behaviors such as regular and heavy alcohol use are often initiated during the teenage years and continue on into early adulthood . RegularOPRM1 gene codes for the μ-opioid receptor and is associated with pain modulation  and DRD4 (521CT) have been studied in relation to addictive behaviors. The A1 allele of the DRD2 (Taq1A) polymorphism has been associated with reduced expression of the D2 dopamine receptor  associated with dopamine receptors receptor . Meta-anreceptor , 11 albebehavior –14 althodrinkers . There hThe COMT gene codes for the catechol-o-methyltransferase enzyme that degrades neurotransmitters . The MetTaken together, the literature regarding the above candidate genotypes and alcohol consumption is somewhat inconsistent, which may be due to differences across studies including varying ethnicity, clinical heterogeneity, and sample selection such as studies of young social drinkers vs. adult dependent drinkers. This study thus aims to extend this literature by investigating the relationship of the above-mentioned candidate genotypes on prospective alcohol consumption across a 2 week period in a sample of university students.Participants were 628 young adults aged between 18 and 25 years of age studying at the University of Otago, New Zealand , and completed a final survey. Participants were asked in the daily diary how many standard drinks they had consumed the night before and were given a guide to estimate it.OPRM1 (A118G), DRD2_taq1A (ANKK1-Taq1a variant), DRD4_521(C521T), COMT  were obtained from blood (99%) or saliva samples. DNA was extracted from peripheral white blood cells using a guanidine-HCl-based procedure with chloroform extraction  to adjust for multiple hypothesis testing. Based on an estimated sample prevalence of G- for OPRM1 for AUD vs. non AUD in young social drinkers (51.9 and 16.3%) with a medium magnitude effect size, estimated from , gender was included as a control fixed factor main effect and a moderator with genotype. Ethnicity in this sample was also heavily skewed toward European Caucasian (79%) and was likewise added a control fixed factor (European Caucasian or Non-European Caucasian). The N = 628 university students who were predominantly female  and predominantly of European ethnicity . The average number of surveys completed was 11.41 (SD = 1.945) out of 13, which was an 88% response rate. Participants consumed an average 7.5 standard drinks (SD = 4.69) per drinking day, with a overall median of 3 drinking sessions (range: 2–8).Genotype distributions per polymorphism are depicted in OPRM1 A118G polymorphism were GG (N = 12), GA (N = 97), AA (N = 358), which were in HWE . Fixed effects tests revealed males consumed significantly more drinks per day than females (p <0.001), but there were no significant effects of gene variants, ethnicity, or genotype and gender interaction (p's > 0.218).Genotype distributions of the DRD2 Taq1A polymorphism distributions were A1/A1 (N = 381), A1/A2 (N =208), A2/A2 (N =36), which were in HWE . Fixed effects tests demonstrated males consumed significantly more drinks per drinking day than females (p <0.001). There were trends for DRD2 Taq1A variant differences (p = 0.089), and stronger trend toward an interaction of polymorphism variant and gender interaction (p = 0.059), with fixed effects estimates showing a significant interaction with gender and comparison between homozygous variants A1/A1 vs. A2/A2 (p = 0.048). Sidak-adjusted pairwise comparisons of these variants stratified by gender revealed males with the A2/A2 variant (estimated mean = 13.7) drank significantly more per day than males with A1/A1 variant (estimated mean = 8.58) (p = 0.021), with no effect seen for females or other comparisons (p's > 0.113). No effect for ethnicity was seen (p = 0.216).DRD4 C521T polymorphism distributions were CC (N = 123), CT (N = 275), TT (N = 224), which were did not deviate from HWE . Fixed effects tests again demonstrated males consumed significantly more drinks per drinking day (p <0.001). However, no main effects of ethnicity, gene variant, or variant by interaction effects were observed related to number of drinks per drinking day (p's > 0.365).COMT Val158Met polymorphism were GG (N = 168), GA (N = 296), AA (N = 163), which were in HWE . A significant gender effect was seen with males consuming more drinks per drinking day (p <0.001), but no significant main effects for ethnicity, variant, or variant and gender interaction upon number of drinks per drinking day were seen (p's > 0.348).Genotype distributions of the OPRM1 A118G, COMT Val158Met and DRD4 C521T SNPs. There was a trend for an effect of the DRD2 Taq1A on the number of drinks per drinking day and for the interaction of gender and DRD2 Taq1A on the number of drinks per drinking day.No evidence of main effects of gene variants upon consumption per drinking day were seen in this sample of young adult social drinkers. There were also no significant gene x gender interactions found for DRD2 Taq1A on alcohol consumption and presence of alcohol dependence has been previously reported in the literature. One meta-analysis demonstrated that positivity of the A1 allele was associated with a greater odds of alcohol dependence , and conformity  that may not be present for older adults  did not consent for their data to be publically available. Requests to access the dataset should be directed to TC at The studies involving human participants were reviewed and approved by University of Otago Human Ethics Committee (10/777). The patients/participants provided their written informed consent to participate in this study.TC conceived the Daily Life Study and led collection of the behavioral data. TM led the genetics analysis. KM, WL, PC, and BR conceived the paper idea. WL performed the statistical analysis with assistance from PC and BR. PC and KM wrote the article with assistance from WL. All authors read and reviewed the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The use of telemedicine has greatly increased, largely derived from the COVID-19 pandemic, which has created the need for a guide aimed towards the adequate management of a modality of health care: the video consultation. A Delphi study composed of three rounds was conducted with 16 experts in holding video consultations and managing non-technical skills from different specialties and nationalities to conceive a consensus on the criteria needed for properly managing video consultations by healthcare professionals. The consensus criteria were defined by three dimensions  and their corresponding items. Excellent consensus data was obtained; therefore, use is recommended by any healthcare professional who is going to utilize a video consultation, in order to manage it effectively. The pandemic caused by the novel coronavirus disease 2019 (COVID-19) is a threat to global health [There is no doubt that the COVID-19 pandemic and its rapid evolution has created quite a confounding situation , creatinIt should be pointed out that the World Health Organization  defines Video consultations have been used throughout the world ,24. AlthIt is therefore crucial to ensure the quality of health care through this modality. To achieve this, a set of requirements for video consultation assistance is required that deal with factors such as the ethical issues related to the protection of privacy and confidentiality, creating trust in patients, providing competent health care, ensuring continuity of care , at the To date, some approaches have recommended a range of strategies to hold an adequate video consultation, but these are related to quite specific clinical conditions and diseases, and not aimed at providing general health care for most clinical practice situations and patients through this modality. For instance, the following have been promoted: broad guidelines for ethical conduct related to key issues in telehealth/telemedicine , an examAdditionally, previous telecare experiences, such as the use of telephone calls, have demonstrated that structured telephone assistance is effective, improving patients’ quality of life and reducing costs ,34. TakiAs the video consultation is a novel and innovative topic, the creation of a consensus on criteria for good practices in video consultation using the Delphi method is proposed, as it is an effective method for obtaining a consensus among experts in any given field of study ,36. MoreAccording to Mosadeghrad , includiAll questionnaires were sent electronically using the application Google Forms™ , whose use has increased over the years, demonstrating its effectiveness . MoreoveThree Delphi rounds were carried out during the study between 25 March and 9 June 2020. First round: The Delphi process traditionally starts with an open-ended questionnaire to collect specific information about a content area from experts [ experts . ConsequSecond round: A second self-administered questionnaire was electronically sent to participants to obtain their opinion about the items that should be included in the guideline, including a brief report of the panel’s most outstanding qualitative results. The response rate was 100% (n = 16). The experts scored this using a Likert scale ranging from 1  to 4  to assess the inclusion or not of the different items prepared, after analyzing the content of responses obtained in the first-round survey . In addition, an observations section was included, where experts could add indicators or proposals for change or inclusion of new items that they considered necessary to be evaluated in subsequent rounds.Third round: After the second-round survey, both quantitative and qualitative responses and observations were analyzed. The revised survey obtained was forwarded to experts with the same evaluation criteria , including feedback of both quantitative  and qualitative (more frequent observations) results obtained in the previous round [us round . Once agA content analysis of data obtained in the first round was performed by two different members of the research team who were experts in qualitative methodologies, by analyzing the eight open-ended questions raised in this round through a self-administered questionnaire. This content was performed according to the methodology proposed by Piñuel , which rHigh consensus: the median response was equal to or greater than 3 and at least 80% of the experts scored the element proposed with at least 3 points.Low consensus: the median response was equal to or greater than 3 and 70–79% of the experts scored the element proposed with at least 3 points.No consensus: the median response was less than 3 and less than 70% of the experts scored the element proposed with at least 3 points.Conversely, both quantitative and qualitative data were obtained in the second and third rounds. Regarding the quantitative data collected, as a 4-point Likert response scale was used, the criteria used to decide the consensus on the inclusion of each element proposed were as follows ,43: HighThe major statistics used in Delphi studies are measures of central tendency and level of dispersion in order to present information concerning the collective judgments of the respondents. Generally, the use of median and mode is favored ,43. WhenThe qualitative data collected in the observations section of the questionnaire distributed during the second and third rounds were also analyzed according to the content analysis methodology proposed by Piñuel . More spParticipation was voluntary and the process was anonymous and was carried out following the ethical principles for medical research of the international Declaration of Helsinki . This stA total of 16 national , Madrid (two), Murcia (three), Galicia (two), and Andalusia (three)) and international experts (Mexico (two) and Argentina (two)) on video consultations participated in the study. The mean age of the participants was 44.31 years (SD = 7.854) and most were women . The panel of experts was composed of five psychologists, eight nurses, and three general practitioners (three of these had been in turn patients attended by video consultation). Their average length of work experience was 19.86 years (SD = 9.979), and they had performed 53.43 video consultations on average (SD = 50.029).Availability of other alternative forms of communication in order to be able to contact the patient in case of problems with the video call .To plan the reason for the consultation , and searching for scientific evidence available to resolve any questions, if necessary.To start the conversation, refer to some temporospatial aspect to contextualize .Postpone video consultation if it is not possible at that time due to non-rectifiable connection problems that prevent effective communication, but in that case always agree on the date, time and type of the new interaction to provide continuity.In the case of performing a prior consultation and if it is necessary, summarize its significant aspects, established objectives, and their degree of compliance, as well as strengths and difficulties found during this consultation before presenting the action plan derived from the current video consultation.After performing the content analysis of the experts’ responses to the eight open-ended questions raised in the first round, responses were translated into the questionnaire distributed in the second round. In this second round, consensus on criteria proposed in this questionnaire was achieved, as more than 80% of the experts scored each element proposed with at least three points, obtaining a median response greater than 3.25. However, to increase the degree of consensus, a third round was carried out after refining several items according to the analysis of both quantitative and qualitative data collected (responses to each item proposed and experts’ observations) in the second round. More specifically, an item was removed  since it was redundant in relation to a previous item, and a total of five items were modified in this round :AvailabiOnce again, more than 80% of the experts scored each element proposed with at least three points in this third round, obtaining a median response greater than 3.25. It should be noted that only one expert provided an observation related to an error in the numbering of an item. Consequently, as a high consensus was achieved after this round, no more rounds were needed. Therefore, a series of criteria for good practice in video consultation management were obtained by the consensus of a panel of experts. These criteria were defined by three dimensions . These dimensions and their corresponding criteria are shown in Due to the COVID-19 pandemic, the need has arisen to promote telemedicine, and specifically, video consultation ,14,18. CSome specific aspects should be noted in both video consultation phases  and the context of the patient-healthcare professional relationship, as it is essential to establish an adequate encounter and interaction between them, generating a substantial impact on the participants’ experience . In thisIt should be noted that the high consensus obtained in our study was achieved following the recommended methodology criteria for reporting of Delphi studies ,43. In aAlthough it may seem controversial to create a standard for a unique and personalized act such as a video consultation, in this study an expert consensus was reached to achieve structured and detailed criteria for the steps and indications that are considered essential in this modality of health care. All of these recommendations are flexible and versatile enough for all healthcare professionals  to be able to adapt them to their particular conditions, helping to successfully manage a video consultation. However, it is highly recommended that all healthcare professionals, patients, and caregivers be trained and taught in this modality of healthcare before its real-life use in order to master this technology. In this sense, our guideline includes the availability of other alternative forms of communication in order to be able to contact the patient in case of problems with the video call. In addition, ethical issues related to this technology depend on the specific platform or video consultation software provided by the healthcare service, ensuring privacy and confidentiality. In this case, our guideline includes two elements related to ensuring an environment that is secure, private and confidential. Our study is not exempt from limitations, which are fundamentally related to the Spanish and Latin American origin of the experts selected and the sample size (n = 16 experts). Although there is no standard sample size for the Delphi method, some authors recommend that the sample should range between 20–50 experts , whereasA consensus on criteria for good practices in video consultations management was achieved with a panel of experts using a 3-round Delphi study. The resulting criteria were focused on both video consultation phases  and the context of the patient-healthcare professional relationship. The use of these video consultation criteria is recommended for all health professionals who are going to hold a video consultation. Pilot studies on the use of these criteria for good practice in video consultation management are recommended to analyze their operability, satisfaction, and quality.


Escherichia coli (DEC) infections are common in children in low-middle income countries (LMICs). However, detecting the various DEC pathotypes is complex as they cannot be differentiated by classical microbiology. We developed four multiplex real-time PCR assays were to detect virulence markers of six DEC pathotypes; specificity was tested using DEC controls and other enteric pathogens. PCR amplicons from the six E. coli pathotypes were purified and amplified to be used to optimize PCR reactions and to calculate reproducibility. After validation, these assays were applied to clinical samples from healthy and diarrhoeal Vietnamese children and associated with clinical data.Diarrhoeagenic p < 0.001), was significantly associated with diarrhoea. Multiplex real-time PCR when applied to clinical samples is an efficient and high-throughput approach to DEC pathotypes.The multiplex real-time PCRs were found to be reproducible, and specific. At least one DEC variant was detected in 34.7% (978/2815) of the faecal samples from diarrhoeal children; EAEC, EIEC and atypical EPEC were most frequent Notably, 41.2% (205/498) of samples from non-diarrhoeal children was positive with a DEC pathotype. In this population, only EIEC, which was detected in 34.3% (99/289) of diarrhoeal samples vs. 0.8% (4/498) non-diarrhoeal samples (This approach revealed high carriage rates of DEC pathotypes among Vietnamese children. We describe a novel diagnostic approach for DEC, which provides baseline data for future surveillance studies assessing DEC burden in LMICs. The use of antimicrobials within this study population was high, with 81.3% (1513/1861) of patients receiving empirical antimicrobial treatment prior to any diagnostic testing, which may impact on the detection of various DEC, depending on their susceptibility profile. Fluoroquinolones, specifically ciprofloxacin, were the most commonly used class of antimicrobials in those with a DEC in their stool .Between March 2016 and August 2016, 498 MC sweeps were additionally collected from faecal samples taken from healthy children residing in HCMC and participating in a cohort study . The majp = 0.019, χ2 test)  of diarrhoeal samples vs. 0.8% (4/498) non-diarrhoeal samples .To determine the prevalence and distribution of the various DEC in healthy and diarrhoeal children, we compared the data from the healthy children with a subset of the data from matched children in the diarrhoeal study which were between the ages of 2 and 5 years old . The prevalence of ETEC, EAEC, and EHEC_O157 in faecal samples was not significantly different between children with or without diarrhoea  and EAEC + EIEC/Shigella + ETEC ; whereas EPEC + EAEC  was more common in the healthy control group. Co-infection with more than one DEC was more likely to be associated with diarrhoeal disease than with healthy controls . However, due to the predominant presence of EIEC/Shigella in the diarrhoeal group, EIEC/Shigella infection was a potential confounder.The distribution of DEC co-infection among the cases and the controls was complex and highly variable Fig. . The mosShigella, we performed binary univariate and multivariate logistic regression to identify variables and DEC that were associated with diarrhoeal disease in children aged 24–60 months  and the uidA  are present in both [eae or stx or both may still belong to the EHEC group [stx genes have been found in other pathotypes of E. coli [E. coli to a DEC pathotype without genome sequencing. However, pathotyping DEC through detecting virulence genes remains useful for assessing the potential prevalence of the various pathogenic forms of E. coli in any given population. In addition to the methodological constraints of the study, as our control samples came from healthy children over 12 months of age, we could not evaluate associations with diarrhoea in children under 1 year of age and we recognise that co-infection with organisms that were not detected may impact on disease presentation.Here, we developed and applied an efficient and robust collection of real-time PCR assays for identifying DEC in MC sweeps isolated from stool samples from a collection of healthy and diarrhoeal children. This approach, in comparison to the traditional method, is straightforward, cost-effective and has a comparatively short turn-around time . Ultimat in both . FurtherEC group , 21. In  E. coli , 23. TheWhile ETEC is the most common DEC internationally, the prevalence of ETEC in this setting was found to be considerably lower than other regions , 18. Thistx. These cases may represent mixed infections of EAEC and STEC, or potentially hybrid organisms, such as those associated with an extensive outbreak in Europe in 2011 [EAEC was the most commonly detected pathotype in children with diarrhoea in this study, which is again consistent with earlier studies that reported high detection rates of EAEC compared to other DEC in Vietnam , 25. Sev in 2011 . Althoug in 2011 .EPEC was the most common DEC gene target amplified from faecal samples of diarrhoea and non-diarrhoea children. The overwhelming majority of the amplicons generated from both healthy and diseased cohorts were associated with aEPEC. These data are again consistent with EPEC literature, which suggests that typical EPEC is commonly identified in the African continent , 33, whirfbE_O157 gene alone, which suggests these are likely to be of lower pathogenicity. Only two samples that tested positive for EHEC_O157 also produced amplicons for the Shiga-toxin gene (stx2), suggesting that O157-STEC is not a significant cause of gastrointestinal symptoms in this location. In the age matched comparison, STEC were isolated from children in the healthy group only. This observation is consistent with data originating in Indonesia, where STEC was detected significantly more frequently in non-diarrhoeal children [STEC O157 cause severe diarrhoea and are associated with a high mortality rate in food-borne outbreaks in western countries . EHEC_O1children .Shigella was significantly associated with diarrhoeal disease. However, as EIEC/Shigella infection alone was highly significantly associated with diarrhoeal illness, the contribution of other DEC to disease in EIEC/Shigella infection is unclear. In a multivariate logistic regression model, DEC co-infection in the absence of EIEC/Shigella was not associated with diarrhoea. This suggests that EIEC/Shigella is the most important cause of DEC mediated moderate-to-severe diarrhoea in this setting.In previous studies, co-infection with more than one DEC (or with other enteric pathogens) was found to be significantly associated with diarrhoea , 38–41. Shigella was the only DEC significantly associated with diarrhoeal disease. This study provides new methodology and baseline data for further clinical, epidemiological, and genomic studies in Vietnam and across Southeast Asia and shows that DEC are highly prevalent but not generally associated with diarrhoeal disease in Vietnam.Multiplex real-time PCR is an efficient method for detecting the six major pathotypes of DEC in a collection of clinical samples. This new methodology provides a useful alternative to classical microbiology for large-scale microbiological and epidemiological studies. Using this approach, we found a high prevalence of DEC in the stools of both healthy and diarrhoeal children in Vietnam. EAEC and atypical EPEC were the most commonly detected DEC in both groups; whereas, EIEC/Children aged ≤15 years with diarrhoeal illness admitted to one of the three collaborating tertiary hospitals in HCMC, Vietnam from May 2014 to April 2016 were eligible for enrolment. Those with diarrhoeal illness (cases) were defined as ≥3 passages of loose stools within 24-h period along with at least one loose stool containing blood and/or mucus . We excleltB (heat-labile toxin) and/or estA (heat-stable toxin); EAEC, aggR . The uidA gene, which encodes beta-glucuronidase and is present in all E. coli, was used as an internal control to monitor both DNA extraction and PCR amplification. A flowchart of the combined assay strategy is shown in Fig. The selected target genes for each pathotype were: ETEC, tor gene ); EIEC,  on pINV ); EPEC, nce gene ) and bfpng pilus ); STEC, a toxins ); and rfeltB positive only); ST-ETEC (estA positive only); and LT-ST-ETEC (eltB and estA positive). Amplification of aggR was sufficient for classification as EAEC and a positive amplification for ipaH identified EIEC/Shigella. EPEC positive samples were divided into typical EPEC (carrying both eae and bfpA) and atypical EPEC (the presence of eae only). The STEC pathotype was identified by the presence of stx1 and/or stx2, and the presence or absence of rfb_O157 was used to differentiate between STEC O157 and the non-O157 STEC serogroups. STEC that have the potential to cause HUS carry additional virulence genes, specifically eae and aggR.We classified the DEC amplification results using the following approach; ETEC positive samples were divided into LT-ETEC  were adapted from previous studies [eltB, estA (STh), bfpA, rfbE_O157, stx1 and stx2 . Final primer/probe candidates were blasted against PrimerBLAST (https://www.ncbi.nlm.nih.gov/tools/primer-blast/) to confirm the in-silico specificity of the selected sequences. The selected primer and probe sequences are shown in Table The primer and probe sequences for  studies –49. RefeE. coli strains and a variety of other gastrointestinal pathogens using Wizard Genomic DNA Purification Kit (Promega). PCR amplicons were generated for each of the 11 target genes and ligated into pCR™ 2.1-TOPO® . Purified plasmids were used as template to optimize PCR reactions and measure assay reproducibility. Plasmid concentrations (ng/μl) were quantified using a Nanodrop spectrophotometer , and converted to copy number using the URI Genomics and Sequencing Center online tool (http://cels.uri.edu/gsc/cndna.html).Nucleic acids were purified from prototypic 2, 0.2 μM of each forward and reverse primers, 0.08 μM of each probe and 1 U of Hotstart Taq polymerase . Five μl of DNA template was used for each PCR reaction. The real-time PCR cycling conditions were as follows: 95 °C for 15 min, followed by 45 cycles of 95 °C for 15 s, then 60 °C for 60s, using the Light Cycler 480 II system . The threshold cycle (Ct) value for a positive result was considered to be 38 or less.Multiplex real-time PCR reactions were performed in a 25 μl reaction mixture containing a final concentration of 1X buffer, 0.2 mM deoxynucleoside triphosphates (dNTPs), 3.5 mM of MgClThe precision and reproducibility of the real-time PCR assays were assessed using the co-efficient of variance (CV%), measured by dividing the standard deviations of the Ct values by the mean Ct values for each selected concentration. The Ct values of three replicates assayed simultaneously were compared to measure intra-assay reproducibility. The inter-assay reproducibility was calculated from data generated on three separate days. Linearity was determined by linear regression, using Ct values produced from 10-fold dilutions of control plasmid DNA.Diarrhoeal faecal specimens were collected in sterile containers and transported to the laboratory within 24 h . Anal swEighty μl of the stored colony sweep suspension was centrifuged at 4000 rpm for 10 min, and the pellet was resuspended in 80 μl of molecular grade water (Sigma). The resulting suspension was mixed by gently pipetting up and down, before being boiled at 96 °C for 10 min and cooled to room temperature. The lysate was centrifuged at 4000 rpm for 10 min to remove cellular debris, and 5 μl of supernatant was subjected to the real-time PCR assays.2 test or Fisher’s exact test for categorical variables and the Kruskal-Wallis test for continuous data. Growth status of participating patients were assessed using the WHO global database on growth and nutrition and Prevention and Management of Obesity for Children and Adolescents-Healthcare guidelines using the macro package of Stata v11 developed by WHO [p-value for univariate model was considered significant when p < 0.01. Multivariable logistic regression models were performed and incorporated mono-infections, each specific type of co-infection, gender and growth status with diarrhoea and non-diarrhoea as binary outcomes . For the latter, a p-value of < 0.05 was considered significant. The figure for mixed-infections , and analysed using Stata v11 . Descriptive comparisons between groups were conducted using non-parametric tests including χd by WHO , 51. DueAdditional file 1: Table S1. List of gene accession numbers downloaded from GenBank (NCBI) (https://www.ncbi.nlm.nih.gov/nucleotide/). Table S2. Demographic and clinical manifestations of DEC mono-infection in children hospitalized with diarrhoea.


Saccharomyces cerevisiae, where ACLY is lacking. Strikingly, the drug revealed a powerful anti-aging effect, another property proposed to mark bona fide CRMs. Chronological life span (CLS) extension but also resistance to acetic acid of HCA treated cells were associated to repression of cell apoptosis and necrosis. HCA also largely prevented cell deaths caused by a severe oxidative stress. The molecule could act widely by negatively modulating cell metabolism, similarly to citrate. Indeed, it inhibited both growth reactivation and the oxygen consumption rate of yeast cells in stationary phase. Genetic analyses on yeast CLS mutants indicated that part of the HCA effects can be sensed by Sch9 and Ras2, two conserved key regulators of nutritional and stress signal pathways of primary importance. Our data together with published biochemical analyses indicate that HCA may act with multiple mechanisms together with ACLY repression and allowed us to propose an integrated mechanistic model as a basis for future investigations.Caloric restriction mimetics (CRMs) are promising molecules to prevent age-related diseases as they activate pathways driven by a true caloric restriction. Hydroxycitric acid (HCA) is considered a bona fide CRM since it depletes acetyl-CoA pools by acting as a competitive inhibitor of ATP citrate lyase (ACLY), ultimately repressing protein acetylation and promoting autophagy. Importantly, it can reduce inflammation and tumour development. In order to identify phenotypically relevant new HCA targets we have investigated HCA effects in The online version of this article (10.1007/s10495-020-01625-1) contains supplementary material, which is available to authorized users. The reduction of calorie intake without malnutrition can extend health span in both model organisms and humans by lowering the incidence of age-related diseases. Caloric restriction mimetics (CRMs) can activate some protective pathways driven by a true caloric restriction leading to a beneficial modulation of several cell processes (reviewed in ).WT yeast cells salicylate can alter the balance between cell quiescence, death and proliferation as a function of metabolic signals [Garcinia cambogia [Garcinia cambogia extracts and/or HCA appear to have a low or negligible impact in terms of acute or chronic toxicity, genotoxicity, reproductive failure and teratogenicity. Although sporadic cases of mild or more severe adverse reactions have been registered [Some bona fide CRMs are nutraceuticals, such as salicylate and hydroxycitric acid, HCA . Aspirin signals . Hydroxycambogia , is widecambogia . Garcinigistered , specifigistered –15. Rathgistered –19. Indegistered ). Of notgistered , 22.Importantly, ACLY expression and activity has been found to be aberrantly expressed in many tumours  and its inhibition correlated to repression of tumour proliferation and apoptosis. So, ACLY is considered an anti-cancer drug target with a great therapeutic potential , 23, 24,Saccharomyces cerevisiae gives the unique opportunity to identify new, physiologically relevant, in vivo targets of HCA since this model organism naturally lacks ACLY [The budding yeast cks ACLY , 29. IndS. cerevisiae is a model for eukaryotic cell and can provide significant insights into the human biology of aging [WT) strain were inoculated (day − 4 of experiments) in synthetic glucose medium with variable concentrations of hydroxycitric acid (0–10 mM). After growth there was no further increase in cell numbers and OD values between day − 2 and 0 , considered to be in early apoptosis. This apparent 70–80% of early apoptotic cells was surprising considering that ≥ 50% of HCA-treated cells were still able to form a colony . These findings clearly show that there was an efficient HCA rescue activity from AcA-induced apoptosis independently of chronological aging.Acetic acid (AcA) accumulated in the culture medium has been proposed to partially contribute to the mechanisms of yeast chronological aging . On the S. cerevisiae plays a key role in understanding of the relationships between aging and the non-homeostatic ROS production, given that the mammalian and yeast antioxidant responses are similar [2O2 induced oxidative stress. To this aim both ROS and accumulation of dead cells were followed by staining chronologically aged (day 3 CLS) WT yeast cells with DHR 123 and PI, after a H2O2 treatment in the presence or not of 10 mM HCA. Strikingly, the molecule was able to largely prevent the massive cell death (PI+ cells) caused by the intense oxidative stress. In parallel there was a sharp increase of live cells with high ROS levels (PI−/DHR123+ cells) and a much less pronounced increase of DHR123− live cells . In contrast, both snf1 and cyr1msn2msn4pde2 mutants responded similarly to WT cells, if not even better. Since in the quadruple mutant [To test the idea that HCA could impinge on signal pathways controlling aging, we performed some analyses in cells with deletions of genes affecting CLS (listed in Table e mutant  both cyctps1 mutant) subjected to a treatment with H2O2, we could establish that some of them responded differently to HCA also during a severe oxidative stress. Figure cyr1msn2msn4pde2 and tps1 mutants the response to HCA was similar to that of WT, namely there was mainly a strong decrease of PI+ cells and a corresponding increase in viable cells producing high levels of ROS; of note, in tps1 cells the HCA rescue activity appeared less efficient; (b) In the case of ras2 and snf1 cells there was a similar large increase in viable cells driven by HCA but these rescued cells did not produce high ROS levels. Interestingly, it appeared that not only PI+ cells but also live cells producing high or very high ROS levels cells decreased as a result of the HCA treatment; (c) finally, sch9 mutant responded very partially to the molecule. Indeed, these cells were already very resistant to H2O2 treatment, so mimicking the HCA effect. However, a small additional increase of live (ROS producing) cells induced with HCA was reproducibly measurable.After analysing the same mutants . However, importantly HCA induced a strong OCR repression in sch9 strain as well.In the previous section we have described how some genetic elements able to change yeast CLS could interact with HCA. We also observed that HCA did not alter the exponential growth rate (µ) of yeast populations but it delayed the recovery of growth of quiescent cells  . As far ras2Δ and sch9Δ, two CLS mutations extending longevity [2O2 common to ras2, sch9 [SCH9 was almost fully epistatic to HCA treatment during the cellular response to a severe oxidative stress. However, the residual amount of sch9 cells sensitive to oxidative stress (∼ 10%) were still rescued from cell death by the treatment with HCA. The rescue effect was even more evident in the ras2 mutant although it was more resistant than WT when treated with H2O2: in our extreme conditions, HCA could save ∼ 25% of the population . Finally, sch9Δ mutation was not epistatic at all to the OCR changes induced by the HCA. Indeed, the sch9 mutant showed a full sensitivity to the HCA-mediated partial inhibition of respiration, just like it was observed with WT or snf1 cells. In conclusion, a partial effect of HCA as a molecule modulating Ras2 and Sch9 activities cannot be ruled out, or HCA might be able to modify some targets shared with these regulatory elements. However, it might primarily induce an adjustment of metabolism then sensed by Sch9 and Ras2 as well as other possible regulatory elements, so affecting fundamental nutrient and stress signalling pathways in an indirect way.Genetic analyses indicate that ongevity , 51, wers2, sch9 , 47, 52 S. cerevisiae, with the exception of ACLY. In addition, many of them are allosterically controlled by citrate (CA) or citrate is part of the specific reactions they catalyse (Table S2). Indeed, citrate is a crucial sensor and regulator of cell energy level. It can control catabolic pathways through the negative feedback inhibition of key regulatory enzymes of glycolysis (e.g. phosphofructokinase 1 and 2) and TCA cycle (e.g. pyruvate dehydrogenase), so adjusting ATP production reviewed in [Biochemical in vitro and in vivo analyses on hydroxycitrate performed in the past support more this latter hypothesis, since HCA was found capable to either inhibit or activate several metabolic enzymes . Thiewed in , 55). Atiewed in  and fattiewed in , 58. Giviewed in , 60), HCIn principle, the above picture could account for the HCA-induced inhibition of OCR and the delay of growth recovery of stationary phase cells. Of note, the exponential growth rate was unchanged by the same HCA concentrations, suggesting that the molecule was able to modulate and likely optimize the metabolic pathways rather than repressing them. We hypothesize that this metabolic control can be directly involved in the pro-longevity/anti-apoptotic properties of HCA, similarly to the effects of low glucose CR. The observation that the product of PFK1, fructose 1,6 bisphosphate, can activate the pro-aging and pro-apoptotic Ras2 protein  stronglyS. cerevisiae cells expressing ACLY [In conclusion, in yeast HCA produces dramatically positive effects on cell resistance to aging and stresses despite the lack of ACLY, possibly by directly impinging on metabolism, hence lowering the signals controlling at least Ras2 and Sch9 driven pathways. In higher eukaryotes, ACLY inhibition with HCA must also increase the citrate levels . Our moding ACLY , 69 and,Yeast strains are listed in Table snf1 or tps1 strain grown in SD + 5% glucose or 2% galactose, respectively. Growth was monitored either by measuring the absorbance ad 600 nm (OD600), or by counting the cell number with a Coulter Counter (Beckman-Coulter Z2) after a mild sonication [Cells were grown at 30 °C with shaking (200 rpm) into liquid synthetic defined media (SD) containing 2% glucose, 6.7 g/l YNB w/o amino acids  and the proper selective drop-out CSM , with the exceptions of nication .We used one of the established procedures to measure CLS, as described by Fabrizio and Longo , growingProtocols used were basically as those previously described , 73 and r.t. and samples were immediately analyzed with flow cytometer (CytoFLEX©).Cells suspended in PBS were stained with DHR123 (Sigma)  for 120 min at 30 °C in the dark, with gentle shaking. Next, PI (3 µg/ml) was added for 15 min at 8 cells per treatment of exponentially growing cells (0.6–1.0 × 107 cells/ml) were collected by centrifugation, suspended in 0.5 ml of sterile water, mildly sonicated and transferred to SD (2%) at pH 3 [7 cells/ml. In cultures that had been treated with HCA (10 mM) the molecule was added again into the new medium at pH 3 at the same concentration. Cell suspension was divided in aliquots for incubation (30 °C) with or without the addition of 80 mM acetic acid. After incubation (till 200 min), CFUs were determined and/or spheroplasts were prepared for Annexin V/PI staining.10 at pH 3  to obtai7 Cells were collected after 1, 2 or 3 days CLS plus or minus 10 mM HCA and sonicated. After, H2O2 at the final concentration of 70 mM was added and cells were incubated for 20 min at 30 °C while gently shaken. H2O2 exposure was stopped by centrifugation and resuspension in 0.5 ml PBS buffer. Staining with DHR123/PI was performed as described above.5 × 10Oxygen consumption rate (OCR) was measured with an oxygen electrode system . Oxygen consumption was detected polarographically by a S1 Clark-Type electrode in a 1 ml liquid-phase reaction vessel following the manufacturer instructions. Basal OCR and rates induced by HCA addition to the polarographic chamber were normalized to total protein content .Supplementary file1 (PDF 1680 kb)Below is the link to the electronic supplementary material.


We sought to evaluate the feasibility and benefits of using video-based scenarios in Multiple Mini Interviews (MMIs) to assess candidate’s empathic abilities by investigating candidate perceptions and the acceptability, fairness, reliability, and validity of the test.The study sample was candidates for admission interviews held in the MMI format at a medical school in South Korea. In this six-station MMI, one station included a 2-min video clip of a patient-doctor communication scenario to assess candidate emphatic abilities, whereas paper-based scenarios were used in the other stations. Candidate’s perceptions and acceptability of using the video-based scenario in the empathy station were examined using a 41-item post-MMI questionnaire. Fairness of the test was assessed by means of differences in candidate perceptions and performance across different demographics or backgrounds. Construct validity was assessed by examining the relationship of candidate performances in the empathy station with those in other stations. The G-coefficient was analyzed to estimate the reliability of the test.Eighty-two questionnaires were returned, a 97.6% response rate. Candidates showed overall positive perceptions of the video-based scenario and they found it authentic and interesting. The test was fair as there were no differences in candidates’ perceptions of the patient-doctor relationship presented in the video clip and neither in their performance nor in their perceived difficulty of the station across demographics or backgrounds. Construct validity was established as candidate performance in the empathy station was not associated with that of any other stations. The G-coefficient was 0.74.The present study demonstrates that the video-based scenario is a feasible tool to assess candidate’s empathy in the MMI. Student selection is an important step in educating tomorrow’s doctors, and during this process, it is critical that candidates’ cognitive and non-cognitive attributes be assessed in order to select those with the qualities required of good doctors . SeveralAlthough MMIs are widely recognized as a selection tool in medical education, our review of relevant literature indicates little attention has been paid to using technology in MMIs. There has been a plethora of research and practice on using technology in medical education to improve student learning and assessment , 19. MorCandidates’ various non-cognitive attributes have been assessed in MMIs. In particular, empathy, which is “a personality trait that enables one to identify with another's situation, thoughts, or condition by placing oneself in their situation ,” is an In the present study, we examined the feasibility of using a video-based scenario in the MMI to assess candidates’ empathic abilities. In general, MMI scenarios are presented in a paper format, but technological developments offer opportunities to adopt other formats for presenting scenarios during MMIs. In particular, it has been advocated candidate’s non-cognitive attributes need to be assessed in authentic contexts . ConsequWe considered that presenting candidates with a scenario involving human interactions on a video vignette would be likely to provide richer contexts than scenarios presented as text. The use of videos to present cases or problems has been studied in case-based learning (CBL) and problem-based learning (PBL) situations, and these studies have shown video-based CBL and PBL are more effective than using paper-based alternatives in terms of fostering critical thinking and interest –29. TherThis study was conducted on candidates that participated in admission interviews at Dongguk University School of Medicine (DUMS), a private medical school in South Korea, for matriculation in 2019. DUMS has a 4-year basic medical education program for graduate-entry students and an annual intake of approximately 50 students. DUMS has implemented admission interviews for those that passed the initial screening stage based on considerations of prior academic achievements, including undergraduate Grade Points Average (GPA) and performance at the Korean medical school entrance exam . As a result, 84 candidates attended admission interviews, which were conducted in December 2018.DUMS has implemented MMIs for admission interviews since 2014. Interview schedules are composed of six mini-interviews conducted at separate stations, and the allocated time per station is 10 min. There was one assessor for each station, who evaluated the candidates’ performance on a 5-point scale of 1 being “unsuitable” to 5 being “outstanding” on two to three items presented in a scoresheet. Candidates’ performances are assessed by each station score and their overall performance is determined by summing up the scores at each and every station. Previous experiences with the MMI at DUMS have shown that it is a feasible tool for student selection , 31.A video-based scenario was developed for one MMI station to assess candidate’s empathic abilities. MMIs at the other five stations were implemented in a traditional paper-based format. Three medical faculty members participated in the development of the video-based scenarios for the empathy station. Two were experts in MMIs and the other was a psychiatrist, who wrote the script for the scenario. Two investigators with experience of MMIs reviewed and revised the draft scenario. The video was produced in-house and was pilot tested on a volunteer medical education graduate student. The student was asked to think aloud what she thought of the video clip as she watched it and reported whether she thought the situation was presented clearly in the video and whether there was any unambiguity in the dialogue.The video vignette presented a fictive clinical situation where a doctor interviewed a patient who seemed to be in a depressive mood. The vignette lasted around 2 min because of time constraints for the candidate to view and prepare for him/her to discuss it with the assessor. Candidates used a tablet and a headset to watch the video. During the interview, candidates were asked to assess the extent to which the doctor showed empathy and to elicit the feelings and views of the patient shown in the video, which are considered key elements of empathy in doctor-patient interactions . The canData on candidate perceptions and performance in the MMI stations were obtained and analyzed to investigate its acceptability, fairness, validity, and reliability as evidence regarding the feasibility of the test. Acceptability by candidates and their perceived benefits of the video-based scenario was examined by using a post-MMI questionnaire. Fairness of the test was assessed by means of differences in candidate perceptions of the MMI and of video-based scenario and in their performance in the empathy station across different demographics or backgrounds. Construct validity was assessed by examining the relationship of candidate scores in the empathy station with those in other stations. Moreover, we calculated the G-coefficient to investigate its reliability using the variance components method.The post-MMI questionnaire used in this study consisted of 41 items with Likert-type responses ranging from “strongly disagree” (1) to “strongly agree” (5). The questionnaire is composed of the following four sections. The first section included 7 items regarding candidate demographics and backgrounds. The second section consisted of 17 items that elicited candidates’ overall perceptions of the MMI. The items in this section were adapted from the instrument developed by Eva et al.  and haveThe questionnaire was administered during a wrap-up session conducted immediately after all interviews had ended in the morning and afternoon sessions. Participation in the study was voluntary and consent was implied by return of the questionnaire as responses were collected anonymously. An ethical review was conducted and the study was exempted from the requirement for informed consent by the institutional review board of Dongguk University, Gyeongju.t test was conducted to compare candidates’ responses and performance with respect to gender and age, for which they were dichotomized about median age (25 years), and their geographic locations . ANOVA  was used to compare candidates’ perceptions with respect to undergraduate backgrounds, which were categorized into seven groups. The G-coefficient was analyzed to investigate the reliability of this test, which indicates the proportion of variance in MMI score attributable to differences in candidates’ non-cognitive abilities [p values < 0.05.Descriptive statistics were used to analyze candidate responses to the post-MMI questionnaire and their test scores in the MMI stations. Reliability of the research instrument was assessed using Cronbach’s alpha coefficients. The independent bilities . The datn = 35), engineering (n = 25), sciences (n = 15), health-related professions (n = 10), social sciences and humanities (n = 3), and others (n = 4). Thirty-eight (46.3%) of them were from urban areas, whereas 44 (53.7%) were from rural areas.A total of 82 questionnaires were returned, which yielded a 97.6% (82/84) response rate. Twenty-six of the respondents (31.7%) were female and 56 (68.3%) were male; their ages ranged from 22 to 36 years . Candidates’ undergraduate backgrounds were as follows: life sciences  and with respect to station difficulty . Nine candidates (10.7%) answered the time allocated to prepare responses to the assessor in the empathy station was too short, whereas the remainder (89.3%) thought it adequate.Table Table p < .05), and younger candidates showed more interest in it than their older counterparts (p < .05). Moreover, there were no differences in candidate perceptions of empathy from the patient-doctor relationship portrayed in the video clip across genders, ages, locations, or with undergraduate majors.Table Candidates’ performances in the MMI are presented in Table Table Table The present study illustrates the feasibility of using the video-based scenario in MMIs to assess candidates’ empathic abilities by demonstrating the acceptability, fairness, validity, and reliability of the test. This study also found benefits of using video-based scenarios in MMIs as they present scenarios in an authentic way and hold candidates’ interest.Our study showed the positive acceptability of our new MMI station by the candidates. The candidates reported overall satisfaction with the use of video-based scenario in the MMI and they agreed it was authentic and interesting. Our study demonstrates that there are benefits of using video-based scenarios in MMIs as they present scenarios in an authentic way and hold candidates’ interest. The findings concur with that observed in other studies that showed using video-based cases in assessments for the health professionals enhanced its authenticity  and thatIn terms of candidate perceptions of the video-based scenario for the MMI, this study found the male candidates were more satisfied with it than females, and younger candidates showed more interest in it than their older counterparts. This finding may indicate the digital technology preference among younger males . Yet, thThe candidates generally evaluated that the patient-doctor relationship presented in the video was not effective in terms of emphatic communication, which was intended in this case scenario. This finding indicates candidates were generally able to identify the level of empathy that the doctor showed in the patient-doctor communication depicted in the video. The candidates did not differ in terms of their interpretations of patient-doctor relationship depicted in the video with respect to age, gender, geographic, or undergraduate backgrounds. Moreover, candidates’ performance at the video-based MMI station and their perceived station difficulty did not differ with respect to their demographics or backgrounds. These findings indicate that this MMI station using a video-based scenario was fair as it was not biased against candidates on the basis of age, gender, undergraduate majors, or geographic locations.Our study showed the test was reliable in terms of the generalizability theory, which demonstrated a reliable level of G-coefficient. Moreover, candidate performance in the empathy station was not associated with that of any other stations, which indicate this station assessed candidate attributes that were different from other stations. This finding offers evidence for the construct validity of the test.Several limitations should be acknowledged. First, the video vignette used in this study was designed to assess candidate’s empathic abilities. It is known that individual’s non-cognitive abilities are context-specific , which mOur findings indicate that the use of a video-based scenario in the MMI to assess candidates’ empathy was perceived positively by the candidates and it fairly assessed their empathetic abilities as it was not biased against specific demographics or backgrounds. Furthermore, the test was found reliable in terms of the generalizability theory and it was valid as it assessed candidate attributes different from those assessed in the other stations. As Kreiter and Alexson  suggest,This study demonstrates the benefits and feasibility of using a video-based scenario in MMIs to assess candidates’ non-cognitive attributes such as empathy. We believe that using video-based scenarios is more effective in assessing communication and interpersonal skills than using paper formats in MMIs because they include verbal and non-verbal cues that encompass the natures of interactions, which allow for authentic assessment. Although some medical schools have reported using actors or SPs in the MMI to assess candidates’ interpersonal skills, often budgetary constraints prevent the utilization of such resources. Thus, we would argue using video-based scenarios provides a more cost-effective means of assessing candidates’ non-cognitive attributes in MMIs, especially in the domains of communication and interpersonal skills such as empathy.


Cerebral arteriovenous malformation (AVM) is a congenital brain vessels pathology, in which the arterial and venous blood channels are connected by tangles of abnormal blood vessels. It is a dangerous disease that affects brain functioning causing the high risk of intracerebral haemorrhage. One of AVM treatment methods is embolization—the endovascular filling of the AVM vessel bundle with a special embolic agent. This method is widely used, but still in some cases is accompanied by intraoperative AVM vessels rupture. In this paper, the optimal scenario of AVM embolization is studied from the safety and effectiveness of the procedure point of view. The co-movement of blood and embolic agent in the AVM body is modelled on the basis of a one-dimensional two-phase filtration model. Optimal control problem with phase constraints arising from medicine is formulated and numerically solved. In numerical analysis, the monotone modification of the CABARET scheme is used. Optimal embolization model is constructed on the basis of real patients' clinical data collected during neurosurgical operations. For the special case of embolic agent, input admissible and optimal embolization scenarios were calculated. Due tThe haemodynamic associated with intracranial AVMs is complex and varies as morphology and angioarchitecture changes, especially with different treatment methods. Various treatment methods effects on AVM and its environment haemodynamics are presented, for example, in the review of .At the moment, the most common methods of AVM treatment are microsurgical, endovascular and radiosurgical. Endovascular embolization is the selective deactivation of blood vessels from the bloodstream by filling them with a special embolic agent. Modern level of medicine development makes embolization the most preferable method due to minimal invasiveness and possibility of operating in the deep, functionally significant brain areas . This mein vivo, since its nidus  consists of very large number of thin vessels with diameter down to 0.1 mm which exceeds medical equipment resolution. Therefore, various simplified methods for AVM modelling are needed.By type of vessels, connecting the arterial and venous basins, AVMs can be divided into fistula (consisting of large vessels) and racemic . There are also mixed-type AVMs that combine both racemic and fistula parts. Modern medical examination methods such as CT, MRI and cerebral angiography do not allow to determine the detailed geometric AVM structure Mathematical description of blood flow is often based on one-dimensional approximation of Navier–Stokes equations by averaging over blood vessel cross-section. Analytical studies of equations describing flows in pipes with rigid and elastic boundaries can be found in –11. ViscAVM and blood flow in surrounding vessels flow interaction is often studied in analogy with electric and hydraulic networks –20. SuchThe above literature review shows the great interest of the scientific community in this topic. At the same time, the diversity of approaches and models indicates the presence of a fairly large number of open questions. This is due to the fact that an exhaustive anatomical and physiological description of AVM requires detailed knowledge of malformation nidus structure and mechanical and physiological properties of vessels forming it. Modern diagnostic equipment arsenal does not provide all the necessary information. In this regard, used models have sufficiently strong assumptions and simplifications, which, however, allow to obtain qualitatively correct description of haemodynamics in studied anomaly.In this paper, the flow of blood and embolic agent through the AVM body was considered as filtration flow on the basis of Darcy’s Law. Such an approach, in our opinion, is justified for small-vascular racemic AVM compartments' embolization description. Some assumptions on embolic agent behaviour, spatial characteristics of AVM, blood rheology and wall properties are made. Specifically, both liquids are assumed to be Newtonian with constant viscosities, incompressible and immiscible. In numerical calculations, real blood and embolic agent (ONYX18) viscosities were used. AVM is simplified to one-dimensional case with even distribution of its physical characteristics  along model length. Some aspects such as capillary forces, embolic agent adsorption effect and wall properties are neglected.To investigate this process, one-dimensional two-phase filtration model is used leading to the special Buckley–Leverett equation in §Initial-boundary value AVM problem is considered in §2.S ∈ . Now embolic agent concentration is 1 − S. Then Buckley–Leverett equation for blood concentration S looks as follows:θ is physical time, x is the spatial coordinate, m is AVM nidus porosity, A is AVM cross-section, Q is volumetric flow rate of two-phase mixture. The saturation function f(S) is the Buckley–Leverett function and is equal to the volume fraction of the displaced liquid (blood) flow in the total flux of the two phases.Racemic AVM compartments with sufficient modelling accuracy can be considered as a porous medium and are the subject of present research. Blood and embolic agent movement through racemic AVM can be modelled as two-phase filtration process, where the displaced phase is blood, and displacing phase is embolic agent. Blood and embolic agent are considered as incompressible and immiscible liquids. We neglect the interfacial capillary forces—in this case the pressure in the phases is assumed to be the same. In the one-dimensional case, the displacement of one phase by another allows a mathematical description first proposed by Buckley & Leverett . This deS could be written in simplified form ,problems  and /V, with Ei = Qi(t)Pi(t), where Ei are blood energy flows on AVM nidus input and output; Qi, Pi are volumetric blood flow and total blood pressure with i ∈ . V(t) is the AVM volume part occupied by blood.The choice of the value characterizing the risk of AVM rupture is an important question arising in the study of embolization process. To answer this question, the notion of unit load was introduced . Unit loD(t) is another important parameter and is defined as the fraction of AVM vascular space occupied by embolic agent. It can vary from 0 to 1 and for the considered embolization model can be calculated by formulaAVM embolization degree Unit load behaviour for real patients using clinical data was studied in . The conIt is known that simultaneous exclusion of high flow AVMs is accompanied by elevated risk of unfavourable bloodstream redistribution and, as a result, perioperative haemorrhage. In this regard, there is a practice of embolization dividing into stages. In current study, embolization degree is used as the value characterizing the risk of AVM rupture. On the one hand, value of embolization degree greater than 60% is considered dangerous. On the other hand, too small values of embolization degree show that operation was not effective since the pathological vascular bed remains widely open to blood flow and the number of surgical interventions unjustifiably increase. Thus, it is necessary to find some compromise between the risk of complications and the most complete exclusion of the AVM from the bloodstream per one stage.6.p is pressure distribution and Qb is blood volume flow distribution in the AVM. Thus, AVM local unit resistance to advancement of a blood flow is R = ηb/(KAkb(S)). Then AVM full blood conductivity is given by formulaAlong with embolization degree which characterizes AVM fullness by embolic agent, its distribution inside AVM is important. Residual blood flow through the AVM is determined by how much we can reduce AVM blood conductivity, which directly depends on embolic agent distribution in AVM nidus. Blood conductivity can be determined by Darcy’s differential law for blood,N is the number of intervals of a uniform partition of the segment , Si is the calculated blood concentration value on ith interval. If on some interval kb is a zero value, then conductivity G(t) is considered equal to zero. Note that any thin region that could be completely occluded will not be stable, not practically nor theoretically (in the model), and breaks up starting from the leading edge due to Oleinik–Liu condition  is considered.The operation is considered completed at time In other words, it is necessary to choose a boundary control g(t) such that the solution of problems  simultaneously.The following conditions must be fulfilled:problems , 4.1) a a(1)Emboproblems  delivers7.1.f(S)  a a4.1) ant1 and g(t) has the discontinuity of first type at t = t1t1 and t1 vary from 1 to 30 with step 1 while This function approximates the natural embolization process: full AVM cross-section cut-off at the beginning with decreasing embolic agent to the end of operation. Thus, in these scenarios embolic agent input is controlled by two parameters, ol class  is extenol class  and  a at1 and ol class  calculatx changes from 0 to L with constant step h. Number of space partition points is 200. Note that choice of L does not limit problem generality because it can be set any given value by change of variables in  is determined individually for each patient. The number of time steps was chosen in such a way that for each patient for all embolization scenarios the embolic agent reached the vein. Further calculations have no practical meaning. Moreover, embolic agent does not exit the malformation then condition  parameters plane to study optimal embolization problem  is presented in G(T) with level lines shown in solid lines (wiggling is caused by mesh data interpolation). Dashed lines are level lines of embolization degree D(T) with 60% level shown in bold solid line. Points on the right of this line stand for embolization degree greater than 60%. Purple area shows regimes with embolic agent reaching the vein, where condition  so so7.4) sondition  is violaive (see ), then aα ∈ . Objective functional antigradient G and function 1 − D antigradients. Figure 6b shows that for all α ∈  antigradient G and embolization degree D level lines in E of admissible parameters domain along the objective functional antigradient leads us to the boundary of embolization admissible parameters area 1ABCDA since in a bounded area of admissible parameters the objective functional has no internal extrema. It should be noted that starting from the part of the boundary 1DA, we immediately go inside the region of admissible parameters, since objective functional decreases with fixed T while parameter t1 grows. Movement along the part of boundary B, which delivers objective functional minimum. Note that AB and BC projections are empty, since AB and BC are G and D level lines, respectively. But since α ∈  then objective functional gradient projection on the boundary is non-empty on Γ.Let us minimize objective functional  using grB, is discontinuous and corresponds to the function  AVM inlet is completely blocked by embolic agent, and at terminal time t = T embolization is completed and there is no more embolic agent in AVM inlet. At the end of operation time T embolization degree is 60%. The found optimal embolization regime, given by point function . At t = (1)1ABCDA objective functional decreases with fixed T while parameter t1 grows and has no internal minima;inside the area (2)1ABA and DCB towards point B;functional decreases on the boundary while moving along its parts (3)B.embolic agent does not reach the vein during operation with parameter values corresponding to point It is easy to prove that these conditions are sufficient for optimal embolization regime to correspond to the same point B.L, Buckley–Leverett function f(S), which describes malformation properties, and control g(t), which sets embolization regime. Qualitative character of conditions (1)–(3) entail that for Buckley–Leverett functions close to considered embolization regimes will be similar. In particular, it means that Buckley–Leverett function construction from clinical data could be made with sufficiently big error. This conditions will also be valid for close to considered piecewise-linear and nonlinear classes of control function g(t). For all these classes, optimal embolization regime will also lie on the intersection of the main diagonal and level line of maximal admissible embolization degree.The course of embolization is determined by AVM length 1ABCDA part BC disappears and optimal regime lies on the intersection of purple area boundary and main diagonal and also is discontinuous. This case did not appear among the considered patients.Generally speaking, the situation when embolic agent reaches the vein earlier than 60% embolization degree is achieved is not excluded. In this case, boundary B then regime from the neighbourhood of point B could be quite acceptable.Practically, it is impossible to maintain optimal regime exactly. But since objective functional value varies insignificantly in the neighbourhood of point 8.in vivo. Also, Buckley–Leverett functions for malformations were constructed based on the clinical data of real patients, and were used to study the optimal embolization problem. AVM optimal embolization problem was formulated, its numerical solution for special linear embolization regime was constructed, and admissible and optimal embolization scenarios were calculated. The optimal scenario for all examined clinical cases corresponds to a discontinuous embolization regime. Namely, complete closure of AVM inlet cross-section with an embolic agent, then bringing the embolic agent amount in the AVM nidus to admissible maximum and a sharp cessation of embolic agent delivery.In this paper, optimal AVM embolization scenario in terms of safety and effectiveness was studied. Joint blood and embolic agent flow in AVM nidus was described using one-dimensional two-phase filtration model. For simulation, Godunov’s monotonic modification of CABARET scheme was used, which allows calculation of discontinuous solutions for scalar conservation law with a non-convex flow. Absolute permeabilities for intact malformations were determined for real patients in vivo the detailed geometric AVM structure, which consists of a very large number of intertwined thin vessels whose diameter can reach up to 0.1 mm. Therefore, when modelling AVMs, it becomes necessary to use simplified approaches. The paper considers a one-dimensional model of AVM embolization, which allows us to describe important qualitative patterns of this process. In addition to the difficulty of AVM geometry reconstruction, the mathematical description of blood rheology, arterial and venous vessels wall properties, the forces arising in vessels walls, as well as the forces acting on the vessel from the surrounding tissues, the filtration processes through the vessel wall, chemical reactions and other ongoing processes are still far away from completion. Despite this, taking into account the most significant and determining parameters of the system allows one to build mathematical models that give a qualitatively correct description of its behaviour.Available methods for AVM geometry reconstruction from neuroimaging data  make it possible to distinguish vessels with an average diameter of at least 0.5 mm. It is insufficient to determine For a more detailed study of embolization in future, it is necessary to consider more accurate models that take into account additional characteristics of the AVM embolization process. This primarily concerns the uneven distribution of the physical characteristics of the AVM  along model length. More accurate embolic agent behaviour description is also important, since some of its varieties are liquids with pronounced non-Newtonian properties. In addition, embolic agent adsorption in blood vessels walls and its properties variation over time during solidification are of interest. Despite the impossibility at present of complete AVM internal structure restoration using neuroimaging data, macroscopic characteristics such as the shape of cross- sections and the length of AVM nidus can be restored with sufficient for modelling accuracy. In this regard, the next stage of the study may be the consideration of two- and three-dimensional AVM models. To solve the stated modelling problems, further testing, development and improvement of the used numerical CABARET method is necessary.