A molecular dynamics study on nanoindentation experiments is carried out for some single-layer rectangular graphene films with four edges clamped. Typical load–displacement curves are obtained, and the effects of various factors including indenter radii, loading speeds, and aspect ratios of the graphene film on the simulation results are discussed. A formula describing the relationship between the load and indentation depth is obtained according to the molecular dynamics simulation results. Young’s modulus and the strength of the single-layer graphene film are measured as about 1.0 TPa and 200 GPa, respectively. It is found that the graphene film ruptured in the central point at a critical indentation depth. The deformation mechanisms and dislocation activities are discussed in detail during the loading-unloading-reloading process. It is observed from the simulation results that once the loading speed is larger than the critical loading speed, the maximum force exerted on the graphene film increases and the critical indentation depth decreases with the increase of the loading speed. The perfect graphene is a kind of carbonaceous material which consists of two-dimensional honeycomb lattice structures of single layer of carbon atoms. It is the basic unit to build other dimensional carbonaceous materials, such as zero-dimensional fullerenes, one-dimensional carbon nanotubes, and three-dimensional graphite,2. GraphIt is still debatable whether a graphene sheet is truly a two-dimensional structure or if it should be regarded as a three-dimensional structure since it exhibits a natural tendency to ripple, as observed in recent experiments,14-16. Cab initio total energy calculation[Although the above research has been carried out for mechanical properties of graphene, the variation of the values of elastic modulus has not yet reached a consensus. Especially for rectangular graphene films, the relationship between the load and the indentation depth is not clear. Furthermore, there are few papers available which describe the deformation mechanisms and dislocation activities of graphene film during the nanoindentation processes in detail. These investigations are concentrated on tension deformation-28 and sculation, and quaculation. Researcculation also repIn this article, some MD simulations of nanoindentation experiments are performed on a set of single-layer rectangular graphene films with four clamped edges. The dislocation activities and the deformation mechanism are discussed, and a formula is introduced in order to describe the relationship of load and indentation depth and to measure the mechanical properties of graphene.In order to carry out the nanoindentation experiments, one diamond sphere was introduced to simulate the indenter. Figure When performing MD simulations, we use the canonical  ensemble and control the temperatures at an ideal temperature of 0.01 K. In order to avoid the complex effects of the atomic thermal fluctuations, the temperature is regulated with the Nosé-Hoover method and the time step was set to 1 fs. During the simulation, one key step, named energy minimization and relaxation, should be carried out to make the system remain in the equilibrium state with lowest energy. Then, the indentation experiment was executed and the simulation results were output for further research.F) and indentation depth (d) calculated in MD simulations. The moment the load–displacement curve drops suddenly is considered to be a critical moment. In our simulations, the load suddenly decreased once the indentation depth exceeded 5.595 nm, defined as the critical indentation depth (dc), and the corresponding maximum load (Fmax) is 655.08 nN.We take the case of the graphene film with an aspect ratio of 1.2 and the diamond indenter with a radius of 2 nm as an example to describe the indentation experiment in the following. The indenter was placed over the geometric center of the graphene film and forced to move in the direction perpendicular to the original graphene surface. Figure Figure Generally speaking, elastic deformation which is reversible and plastic deformation which is irreversible are two typical kinds of deformation of an object or material in the view of engineering. In order to determine whether the deformation of the graphene film is elastic or plastic, a set of experiments of loading-unloading-reloading processes are conducted. As shown in Figure dc. The graphene sheet almost can make a complete recovery, i.e., restore its initial structures, and the curves of reloading processes almost perfectly match the initial loading curve while the unloading curve shows very small deviations from the initial one, as shown in the inset of Figure • Stage I. The unloading process is done before the indentation depth reaches the critical depth, dc that the unloading process begins. The graphene sheet cannot make a complete recovery, and there exited broken covalent bonds after the unloading process. In the reloading process, the maximum force exerting on graphene is much smaller than that in Figure • Stage II, i.e., the yellow region in Figure According to the available correlation for the indentation experiments of a circular single-layer graphene film in,22,37, od is the indentation depth and F denotes the concentrated force gotten by the graphene film. In Equation 1, the load F consists of two parts: the first part, Fσ(d), represents the term due to the axial tension of the two-dimensional (2-D) film,where σ02D is the pre-tension of the single-layer graphene film, r is the indenter radius, β denotes the aspect ratio and is equal to L/b, and Requ represents the equivalent radius of the rectangular graphene sheet, (Lb/π)1/2. The second one, FE(d), represents the large deformation term,where E2D is the 2-D elastic modulus, i.e., Young’s modulus, of the single layer graphene film. The strain energy density of graphene, as a standard 2-D material, can be represented by the energy of per unit area. Then, the corresponding pre-tension and elastic modulus can be expressed as σ02D and E2D, respectively, with the unit N/m. The common pre-tension and elastic modulus of a 3-D bulk material can be obtained through these 2-D values divided respectively by the effective thickness which is always treated as the layer spacing of the graphite crystal, i.e., 3.35 Å. q is an nondimensional value, q = 1/(1.05 - 0.15ν - 0.16ν2) = 0.9795, where ν denotes Poisson’s ratio, ν = 0.165[r/R > 0.1, the indenter radius has a significant influence on the load–displacement properties[r/R > 0.1; thus, Equations 2 and 3 are corrected by a factor of (r/R)3/4 and (r/R)1/4, respectively.where  = 0.165,21. It ioperties,39. In oAccording to the expression of maximum stress in the plane of a circular elastic film in, the maxFigure ab initio methods[Table  methods. Lee et  methods. Neek-Am methods. In addi methods,22,43,44Fmax and dc are not that obvious. When the loading speed decreases from 1.00 to 0.50 Å/ps, dropping by 50%, the value of dc increases by 33.35%, and the value of Fmax decreases by 8.43% correspondingly. Nevertheless, when the loading speed decreases from 0.20 to 0.10 Å/ps, dropping by 50%, the changes of Fmax and dc are only 1.68% and 0.21%, respectively. The results may be attributed to the fact that the higher the loading speed of the indenter, the less time it takes to go through the graphene sheet, resulting in a higher load and lower indentation depth than those at a lower loading speed, in which situation the load process is much slower. Secondarily, the spherical indenter’s influences on results are observed by changing the indenter radius. The simulations of various indenter radii  are carried out at the speed of 0.20 Å/ps. The results of the load–displacement curve are shown in Figure Fmax increases obviously and the critical indentation depth also becomes greater with the increase of the indenter radius. Finally, after changing the aspect ratio of the graphene film to 1.1 and 1.5, Young’s modulus and the maximum stress of the graphene are obtained using the methods mentioned above. It can be deduced from Figure For further study of nanoindentation properties, a series of simulations have been carried out with different loading speeds, indenter radii, and aspect ratios of graphene film. It is indicated that the speed of 0.20 Å/ps can be regarded as the critical loading speed, as shown in Figure Some MD simulations of nanoindentation experiments on single-layer rectangular graphene sheets have been carried out in order to obtain the mechanical properties of graphene. A correlation between the load and the indentation depth is constructed, and Young’s modulus and the strength of graphene are obtained in the end. The simulation results show that the unloaded graphene film could make a complete recovery if the maximum indentation depth is less than the critical indentation depth, and the graphene film undergoes elastic deformation during the whole loading-unloading-reloading process. However, if the maximum indentation depth is larger than the critical indentation depth, the graphene sheet could not restore its original structures after unloading and the graphene deforms plastically. Based on the simulations of nanoindentation at different loading speeds and indenter radii, it can be observed that the maximum load increased and the critical indentation depth decreased with the increase of loading speed. In addition, the indenter radius has a remarkable influence on the force-displacement curve. As the indenter radius increases, the critical load and the critical indentation depth also increase.2-D: two-dimensional; AFM: atomic force microscope; AIREBO: adaptive intermolecular reactive empirical bond order; GPa: gigapascals; MD: molecular dynamics; NVT: constant number of particles, volume, and temperature; SW: Stone-Wales 5-7-7-5; TPa: terapascals.The authors declare that they have no competing interests.The analysis of the simulation results was mainly carried out by WDW. The simulation processes were mainly conducted by SL, JJM, and CLY. Some fairly helpful proposals about the construction of models were made by YJZ and MLL. All authors read and approved the final manuscript.


Group II introns are self-splicing RNAs that act as mobile retroelements in the organelles of plants, fungi and protists. They are also widely distributed in bacteria, and are generally assumed to be the ancestors of nuclear spliceosomal introns. Most bacterial group II introns have a multifunctional intron-encoded protein (IEP) ORF within the ribozyme domain IV (DIV). This ORF encodes an N-terminal reverse transcriptase (RT) domain, followed by a putative RNA-binding domain with RNA splicing or maturase activity and, in some cases, a C-terminal DNA-binding (D) region followed by a DNA endonuclease (En) domain. In this study, we focused on bacterial group II intron ORF phylogenetic classes containing only reverse transcriptase/maturase open reading frames, with no recognizable D/En region . On the basis of phylogenetic analyses of the maturase domain and its C-terminal extension, which appears to be a signature characteristic of ORF phylogenetic class, with support from the phylogeny inferred from the RT domain, we have revised the proposed new class F, defining new intron ORF varieties. Our results increase knowledge of the lineage of group II introns encoding proteins lacking the En-domain. Group II introns are self-splicing RNAs that act as mobile retroelements and are thought to be the ancestors of nuclear spliceosomal introns et al. http://webapps2.ucalgary.ca/~groupii/index.html#), class F contained only seven introns, whereas 10 unclassified introns also lacked a recognizable D/En region.Class F is the most recently identified bacterial ORF phylogenetic class. It currently includes a small group of bacterial group II introns with a typical class IIB RNA secondary structure, similar in overall organization to the introns of class E We previously showed that the C-terminal portion of class D RT/maturase proteins constitutes a distinctive, characteristic signature of the ORF class, which has been conserved throughout evolution. It constitutes a group-specific functionally important protein region contributing to both maturase function and intron mobility We searched non redundant  databases for class D group II IEPs, using BlastP or TBlastN, with the consensus amino-acid sequence obtained from a multiple sequence alignment (MSA) of domain X and the C-terminal extension of 35 bacterial class D ORFs We focused on group II intron ORF phylogenetic classes containing only reverse transcriptase (RT)/maturase open reading frames (ORFs), with no recognizable D/En region , using all available sequences from the database until 07-03-2012, and the new sequences identified in this work. The phylogenetic relationships between unclassified and class F intron ORFs available from the database were first investigated by comparing phylogenetic trees estimated by maximum likelihood methods from alignments of sequences for the RT and for the X-domain plus its C-terminal extension. These alignments were generated with Geneious Pro software (Biomatters Ltd.) and Clustal W.http://guidance.tau.ac.il. The species delimitation plugin for Genious The alignment used for the phylogenetic analysis of intron ORFs lacking a recognizable D/En region was initially based on the X-domain and C-terminal sequences. It covered a mean of 130 amino acids corresponding to gap-free lengths of 174 unique sequences that were ≤75% identical . The only exceptions were the class A ORF sequences E.c.I4 and S.f.I1 (99% identity), and the Ni.haI1 (class F) and Ni.haI2 (unclassified) ORFs (99% identity). The larger RT-domain, containing a mean of 257 amino acids, was also used for the phylogenetic analysis of a subset of 123 unique sequences with recognizable RT amino-acid sequences . We included representatives Other types of analysis were performed to investigate the influence of the various phylogenetic estimation methods on our results. We carried out Bayesian analysis with the parallel version of MrBayes 3.1 Nucleotide sequences (4–5 kb) containing putative intron-encoded ORFs were analyzed with Mfold for the detection of potential group II intron RNA structures et al. As mentioned above, Simon Bacterial group II intron ORF phylogenetic classes containing only reverse transcriptase/maturase open reading frames, with no recognizable D/En region, belong to class A, which had only three almost identical (99% identity) members, class C, class E and class D. Moreover, class E was split into two clades, E1 and E2 Ricinus communis).We also updated the compilation of class D intron-encoded ORFs and identified 41 not reported in the intron database, 18 of which had a complete RT-X sequence (Table S1). The 67 class D ORFs included in the final dataset originated from 49 different bacterial species belonging to seven subdivisions of Eubacteria ; four originated from nonculturable environmental bacteria, one from an archaea (Euryarchaeota), one from a nonculturable environmental archaea sample and, surprisingly, one was found in a draft plant genome sequence , revealed an associated group II intron RNA structure. Moreover, 13 of the 27 newly identified ORFs related to former class F or unclassified introns were full-length, as were 14 of the 41 new class D ORFs.Phylogenetic analyses were performed on an amino-acid sequence alignment  for domain X and its C-terminal extension for 174 bacterial group II introns, by the maximum likelihood estimation method. The initial set of intron ORFs included all class A, C, D, E, F and unclassified introns reported in the database and the new introns identified in this work. The final dataset used for the analyses contained only selected sequences that were ≤75% identical .et al. The estimated phylogenetic tree supports the existence of the previously described classes C, D and E , but notg1), supported by a bootstrap value of 93%, contains eight different ORFs, including those of the Ca.ac.I1 and Rh.js.I1 introns previously described as “unclassified”. A second group (hereafter referred to as g2) with strong support (99% boostrap) contained 10 different ORFs, including those of the Mx.xa.I1 intron, which had previously been assigned to class F, and the unclassified introns W.e.I5, Ma.sp.I2, Sg.ce.I1 and B.th.I3. A third group (hereafter referred to as g3), with a high posterior probability (1) and high bootstrap values (77%), contained eight introns, including the class F introns D.a.I1 and Ni.ha.I1 and the previously unclassified intron Ni.ha.I2. Finally, a fourth group (hereafter referred to as g4) with strong statistical support (100% boostrap) had eight members, including the class F intron Pe.ca.I3. The relationships between these groups and the major classes remain unclear, because the deeper branches of the tree have yet to be resolved. Notably, maximum likelihood estimation on the basis of a reduced multiple sequence alignment , with the removal of unreliable columns by the GUIDANCE g4 (96%) and g2 (94%). Likewise, high levels of statistical support were obtained for class D (73%) and class E (82%), whereas the short alignment decreased the bootstrap value for classes C and g1 to 57% and 65%, respectively, and provided no significant support for g3 (not shown). In the short MSA tree, phylogenetic resolution was lower, but nonetheless consistent with the monophyly of g2 and g4.Class D, C and other ORFs branched from a common node with a high bootstrap value (79%), but a low posterior probability (0.51). The phylogenetic tree for the domain X and C-terminal amino-acid sequences also suggested the existence of additional varieties of introns, with strong statistical support  and a high posterior probability (≥0.99). One of these new groups . Nevertheless, this phylogeny identifies several specific features. Some of the class C intron ORFs  lie outside the main node, suggesting that they might be divergent ORFs within this class. Intron Sr.me.I2, which remained unclassified in the maturase tree , clustered within g1 in the RT tree. The intron ORFs clustered in g2 contained a characteristic FADD consensus motif, rather than YADD, in the RT5 domain. There was strong support for sister clade status for classes D and E . This phylogeny was not altered by the addition to the MSA of intron ORF RT-sequences representative of classes B, CL1, CL2 and ML, all of which have an En-domain in their IEPs. This intron lineage branched from a strongly supported (95% bootstrap) node, suggesting that the En domain was acquired only once, in a common ancestor , by the maximum likelihood estimation method and Bayesian inference. In general, the inferred phylogeny was congruent with that obtained with the maturase and C-terminal amino-acid sequences. The estimated phylogenetic tree  supporteancestor .−5). The interspecies distance of the monophyletic g1-4 ranged from 1.325 (g3:g4) to 2.740% (g1:g2) divergence, but only g1 and g2 have significant P(AB) values, with g1 identified as the most divergent clade.The interspecies distance between the currently recognized classes C, D and E  ranged fg1-4). Group g1, which contains no introns previously classified as class F, displayed a significant interspecies distance and may constitute a separate ORF-based phylogenetic subclass. By contrast, g2-4 each included group F members and shared a common node with a basal group containing the rest of the former class F introns , and the unclassified intron c-Ku.st.I1. The grouping together of g2-4 and the small basal F group does not seem to be supported by high bootstrap values in the tree. However, we nevertheless propose that class F should be represented by the four former clades until their relationships can be resolved.We have increased the number of known introns in bacteria and added to knowledge concerning the lineage of group II introns encoding RT/maturase proteins lacking a D/En region. We have identified several new intron ORF varieties and revised the definition of the previously proposed class F. We found that the introns used to established class F The relationships between the intron ORF classes of the intron lineage lacking the En-domain remain unclear, because the deeper branches of the tree have yet to be resolved. Nevertheless, the phylogeny based on the RT-domain suggests that classes E and D may be sister clades. We therefore obtained no evidence to support the hypothesis that class E introns form part of the lineage of introns with an En domain in their IEPs The large number of bacterial genome sequences already available and the continual production of additional sequence data provide the basis for successful analyses of group II intron diversity. We expect even greater intron diversity in bacteria to be detected through future surveys of sequence databases, providing insight into the importance of these catalytic RNAs and retroelements in bacterial evolution.Figure S1MSA based on the maturase and C-terminal extension sequences.(TIF)Click here for additional data file.Figure S2MSA based on the RT-domain (RT0-7).(TIF)Click here for additional data file.Table S1Class D group II introns.(XLS)Click here for additional data file.Table S2New varieties of group II introns lacking the En domain.(XLS)Click here for additional data file.


This study investigated the effect on worry of biased attentional engagement and disengagement. Variants of a novel attention modification paradigm were developed, designed to induce a group difference either in participants’ tendency to selectively engage with, or disengage from, threatening meanings. An index of threat bias, reflecting relative speeding to process threat word compared to non-threat word content, confirmed that both procedures were effective in inducing differential attentional bias. Importantly, when the induced group difference in attentional bias followed the procedure designed to influence selective engagement with threat meanings, it also gave rise to a corresponding group difference in worry. This was not the case when it was induced by the procedure designed to influence selective disengagement from threat meanings. These findings suggest that facilitated attentional engagement with threat meanings may causally contribute to variability in worry. HeighteThere has been recent debate concerning whether elevated anxiety vulnerability reflects facilitated attentional engagement with, or impaired subsequent disengagement from, threatening information. Some evidence suggests that such vulnerability is associated with speeded attentional engagement with the locus of threatening information . HoweverThough not resolving this specific issue, the recent use of cognitive bias modification procedures has established that biased attention does contribute to worry. Recent studies using moderate and high level worriers  employedWhile these findings suggest that attentional bias makes a causal contribution to worry, they do not reveal whether it is enhanced attentional engagement with threat, impaired attentional disengagement from threat, or both, that exerts this causal impact. To address this issue, it would be necessary to examine whether inducing a group difference in attentional engagement with threat, or inducing a group difference in attentional disengagement from threat, each serve to produce a corresponding group difference in negative thought intrusions, during a subsequent worry assessment task.It is important to note that attention to the spatial locus of a threat stimulus is not necessarily the same as attention to the threatening meaning of this stimulus, and it is selective attention to threat meanings that is assumed to be the critical causal factor in anxiety. Moving attention toward a given spatial locus does not ensure the semantic processing of stimuli in that region, just as moving attention away from a previously attended spatial locus does not preclude the continued semantic processing of information presented there. For example, non-anxious individuals may avoid focusing on the threatening meaning of a spatially attended stimulus, while anxious individuals may not only process the threat meaning but also continue to focus on it even after shifting attention away from the stimulus location. In this way, an external threat cue could trigger worry, involving attention to internally maintained threatening meanings, which then continues long after disengagement from the location of the original cue.To determine the contribution to worry made by biased attention to threat meanings, a methodology is required that can influence the ease with which attention can be shifted selectively towards or away from processing threatening meanings. In the present study, this was achieved using a novel procedure that required participants to switch between two different types of decision concerning the same stimulus word; an affective decision requiring semantic access (good or bad?), and a non-semantic structural decision (upper or lower case letters?).By employing two alternative variants of this procedure, we sought to induce a group difference in selective attention to threat in either one of two quite different ways. One approach was designed to induce such a difference through training biased selective attentional engagement with threat meanings. This involved participants repeatedly switching from structural to affective decisions for one particular valence of stimuli, with some participants being required to consistently make this switch only for threat words (to encourage selective engagement with threat meanings), and others being required to consistently make this switch only for non-threat words (to discourage selective engagement with threat meanings). The other approach was designed to induce a group difference in selective attention to threat through training biased attentional disengagement from threat meanings. This involved participants repeatedly switching from affective to structural decisions for one particular valence of stimuli, with some participants being required to consistently make this switch only for threat words (to encourage selective disengagement from threat meanings), and others being required to consistently make the switch only for non-threat words (to discourage selective disengagement from threat meanings).If group differences in attention to threat can be successfully induced in each of these two ways then, by comparing such groups in terms of subsequently reported negative thought intrusions, it will be possible to determine whether differential attentional engagement with threat, and/or differential attentional disengagement from threat, causally contribute to differential worry.22.1The study involved two consecutive phases: an attentional bias induction phase and a worry assessment phase. Participants were assigned at random either to a training procedure designed to induce a group difference in engagement bias, or to a training procedure designed to induce a group difference in disengagement bias. In each case, half the participants were exposed to a condition intended either to encourage, or to discourage, the selective processing of threatening meanings. Thus, participants were randomly allocated to one of the four attentional bias induction conditions: (1) increase threat processing by encouraging selective engagement with threat meanings; (2) increase threat processing by discouraging selective disengagement from threat meanings; (3) decrease threat processing by discouraging selective engagement with threat meanings; or (4) decrease threat processing by encouraging selective disengagement from threat meanings. In all cases, participants were required to make two consecutive decisions about each target word, either concerning its structure (i.e. upper or lower case of the letters) or its semantic content , but these decisions varied according to attentional bias induction condition see .Following the attention bias induction phase, all participants completed 2.2χ2 = 6.18, ns. Groups also did not differ significantly in scores on the PSWQ  = 2.20, ns.) or State-Trait Anxiety Inventory Trait version . Average age was 19.5 (SD = 2.7), with no significant age difference between groups, F < 1.Sixty-four student participants were selected based on their scores on the Penn State Worry Questionnaire PSWQ; . Due to 2.32.3.1M = 6.44, SD = 0.70), while the non-threat words all had a mean rating below 3.00 . Of the final set of 96 words, 64 were assigned to attention modification trials and 32 to test trials.A set of 96 words (48 threat and 48 non-threat) was selected from an initial pool of 377 words, based on ratings provided by ten independent judges. These judges rated each item on a 7-point scale . The threat words selected for use all had a mean rating above 6.00 , or to its emotional meaning (i.e. whether the word was “positive”/“good” or “negative”/“bad” in meaning).1On each trial a fixation cross appeared in the centre of the screen for 1500 ms, after which the first question appeared . After 1000 ms this was replaced by a target word  that appeared for 400 ms. Participants were instructed to quickly answer the first question correctly, by pressing the corresponding “y” (yes) or “n” (no) key. Incorrect responses were signaled by a short error tone. Immediately following registration of the participant's response, the second question about the word appeared . The next trial commenced 1500 ms after the participant responded to the second question.The exact sequence of events within trials varied according to participant group  was 0.89.Finally, participants were asked to expand on the thought intrusions reported during the breathing focus periods. For each intrusion, the experimenter read aloud the participant's summary, and asked them to describe what was going through their minds at the moment they originally had that thought. Descriptions were recorded for later rating by a psychologist, who assessed the valence of each intrusion. To assess reliability, a psychology student also rated 16 participants’ thought expansions. Neither assessor was informed about group allocation, nor when the intrusion occurred. Inter-rater reliability for assessors’ valence ratings using Cohen's Kappa statistic  or given course credit.33.1Data from the attentional bias induction task was first analyzed for accuracy to determine if there were any group differences. Then the reaction time data from the assessment trials were investigated in the following way. To determine whether the task was successful in inducing differential attentional bias to threat as intended, the median response latencies for the second  decision were calculated for each participant. Then a threat bias index was computed for each participant, reflecting relative speeding to make this content decision on threat words compared to non-threat words (by subtracting median latency on threat words from median latency on non-threat words). A higher score on this threat bias index reflects the facilitated processing of threat word content relative to non-threat word content, consistent with selective attentional bias to threatening information. The threat bias index was analyzed by examining the effects of Modification Type (engagement vs. disengagement) and Modification Direction (increase threat processing vs. decrease threat processing) to determine whether the targeted attentional biases had been induced. Finally the negative thought intrusion data was analyzed to determine the effects of Modification Type and Modification Direction, Time (pre- vs. post-worry induction) and Rater (participant vs. assessor).3.23.2.1SD = 2.8) on training trials, and 96.1% (SD = 2.7) on assessment trials, with no significant difference in accuracy between the four groups  = 1.03, ns). Hence, any group differences on assessment trials could not be attributed to differential speed-accuracy trade-offs.Accurate responses to target words averaged 95.8%  = 15.52, p < .001, f2 = 0.50. This reflected the fact that participants in the decrease threat processing groups obtained lower threat bias index scores than did those in the increase threat processing groups . Therefore, as intended, the bias induction procedure did indeed appear to induce group differences in selective attention to threat meanings. Importantly, Modification Type did not influence attentional bias index scores, either as a main effect F = 1.34, ns., f2 = 0.15, or in an interaction involving Modification Direction, F < 1. Hence the procedures designed to induce a group difference in attentional bias through the manipulation of selective engagement with, and selective disengagement from, threat meanings were equally effective in inducing such a group difference in attentional bias. Indeed, t-tests on threat bias index scores, revealed similar effects of Modification Direction, in terms of the resulting magnitude of group difference in attentional bias, whether the induction procedure targeted engagement bias (t(30) = 2.96, p < .01, d = 1.08) or disengagement bias (t(30) = 2.60, p < .05, d = 0.95).A two-way ANOVA was carried out on these threat bias index scores that considered the between-group factors: Modification Type (Engagement vs. Disengagement); and Modification Direction (increase threat processing vs. decrease threat processing). See 3.3F = 9.89, p < .005, f2 = 0.40, with more negative thought intrusions post- than pre-worry induction (M = 1.95 vs. M = 1.35). There was also a main effect of Rater, F = 4.76, p < .05, f2 = 0.28, with participants themselves identifying more negative thought intrusions than the assessor (M = 1.76 vs. M = 1.55). More critically, a significant interaction now was obtained between Modification Type and Modification Direction, F = 5.15, p < .05, f2 = 0.29, which was the only other significant effect to emerge from the analysis. This interaction was not further qualified by Time  = 1.12, ns.), suggesting that the impact of modifying attentional selectivity was not restricted to the persistence of worry only after it was experimentally induced, but was equally evident on the measure of tendency to worry taken prior to the experimental worry induction. Nor was it modified by Rater (F < 1), indicating that it did not reflect the impact of bias induction on participants’ criteria for classifying the valence of thought intrusions.The number of negative thought intrusions recorded during each breathing focus period, as categorized by participants and assessor, are presented in M = 1.92, SD = 1.38, vs. M = 1.67, SD = 1.76 t < 1). In contrast, for participants exposed to the procedure designed to create differential attentional bias through inducing discrepant patterns of selective engagement with threat, there was a strong effect of Modification Direction on negative thought intrusions. Specifically, the condition designed to decrease threat processing (discourage engagement with threat meanings) now led to fewer negative intrusions than did the condition designed to increase threat processing  = 3.12, p < .01, d = 1.14). Thus, when the bias induction procedure served to induce a group difference in selective attention to threat through a contingency designed to affect attentional engagement with threat, then it also served to create a corresponding group difference in worry symptomatology, which was not the case when differential attention to threat instead was induced through a contingency designed to affect attentional disengagement from threat.The interaction between Modification Type and Modification Direction was investigated further. For participants exposed to the procedure designed to create a group difference in attentional bias through inducing discrepant patterns of selective disengagement from threat, there was no effect of Modification Direction on negative thought intrusions, with a similar number of such negative intrusions being evidenced across the conditions designed to decrease or to increase threat processing (4This study introduces a novel attentional bias modification method, designed to induce group differences in selective attention to threat meaning, rather than only to the spatial location of threat stimuli. Participants who completed attentional induction procedures designed to decrease processing of threat meanings were slower to process the semantic content of threat words relative to non-threat words than were participants assigned to induction procedures designed to increase threat processing. This effect was equally evident whether the bias induction procedure involved training that targeted biased attentional engagement with, or biased attentional disengagement from, threat meanings. However, while these different induction bias procedures were equally effective in inducing differential selective attention to threat meanings, they had quite different effects on subsequent patterns of worry.When the attentional bias induction procedure encouraged selective attentional engagement with threat meanings, the frequency of negative thought intrusions on the worry task was greater than when the procedure was designed to discourage selective engagement with threat meanings. In contrast, no such differences in negative thought intrusions were found between the attentional bias induction procedures designed to encourage or discourage selective attentional disengagement from threat meanings. These findings are not readily attributable to differences in performance accuracy between the alternative attention induction tasks, since groups did not differ in these respects. Rather, this pattern of results indicates that variability in selective attentional engagement with threat, but not variability in attentional disengagement from threat, causally impacts on negative thought intrusions indicative of worry. Consequently we suggest that biased attentional engagement with threat meanings influences the tendency to worry, perhaps by affecting the degree to which selective attention is drawn towards those negative aspects of the situation that serve to trigger negative thoughts.Previous research has yielded evidence that elevated anxiety vulnerability is associated with both biased attentional engagement with, and biased attentional disengagement from, the spatial locus of threatening stimuli. As noted earlier, such patterns of attention to spatial loci need not imply that anxiety vulnerability is characterized by both biased attentional engagement with, and disengagement from, threat meanings. Furthermore, even if anxiety vulnerability is found to be associated with both increased engagement with and impaired disengagement from threat meanings, this would not permit the inference that each form of attentional bias contributes to anxious symptomatology. Addressing this issue requires the development of procedures designed to induce either differential selective engagement with or disengagement from threatening meanings, in order to reveal their respective effects on anxiety symptoms. The present research has adopted this approach and, at least with respect to worry, suggests that biased attentional engagement with threatening meanings may be more critical than biased attentional disengagement from such information in causally contributing to worry-related negative thought intrusions. Future research should examine whether this remains true when people are already engaged in worrying and in clients with Generalized Anxiety Disorder.In conclusion, we report the first attempt to induce differences in selective attentional engagement with, and in selective attentional disengagement from, threat meanings, in order to distinguish the causal contributions made by each pattern of attentional selectivity to worry. A procedure designed to induce differential selective attentional engagement with threat meanings served to influence negative thought intrusions, whereas a procedure designed to induce differential attentional disengagement from threat meanings did not, despite the fact that both procedures succeeded equally in inducing differential attentional bias. It would appear that enhanced attentional engagement with threat meanings may causally contribute to negative thought intrusions indicative of worry.


This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes. In 1928, in the former Soviet Union Moerqiafu invented the radiosonde, which had the advantages of compact volume, simple observation technique, and the reliable detection results. Its measurement range was from 10 to 15 km. and soon it was widely used to acquire meteorological data. Vaisala, who is the founder of the Vaisala Company, invented the first electromechanical radiosonde. In the 1980s, the production of the analog electronic radiosonde RS80 ocurred, and in recent years, a digitized RS92 radiosonde was developed , when R > 0, meaning that the theoretical humidity data and actual humidity data are related; When R = 1, it means the theoretical humidity data coincide with the actual humidity data; and when the R = 0, it means the theoretical humidity data and actual humidity data are not related.The value of 3.3.1.The platinum resistance wire (99.999% purity), with a diameter of 0.023 mm, is used to get the atmospheric temperature aloft. A photograph of the platinum resistance wire and temperature sensor is shown in A = 3.9083 × 10−3 °C −1, B = −5.775 × 10−7 °C −2, C = −4.183 × 10−12 °C −3, tR is the resistance value at t °C, and R0 is the resistance value at 0 °C. According to IEC751 international standards, the temperature coefficient of the platinum resistance is 0.003851. In a low temperature environment, platinum resistance has better linearity and smaller measurement errors. Furthermore, a platinum resistance wire, with a faster response speed, can be in contact with the external environment.3.2.Temperature sensor performance testing was undertaken in an alcohol trough. The temperature was increased from −20 °C to +50 °C in 25 min. The corresponding regression analysis result is shown in R = 0.9999, SSE = 0.9191. The results show that the actual temperature value is very close to the theoretical one. Such a small error reveals a successful estimation of the temperature data.Putting the data into the regression equation, we obtained 4.γ stands for the volume fraction of water in the polyimide film. This sensing capacitance of this type of sensors is given by [ε0 stands for the vacuum dielectric constant, d refers to the distance between the capacitor plates and A is the capacitor sensing area.The sensitive material of the humidity sensor is polyimide. The dielectric constant for the polyimide film with absorbed water can be given by Looyenga's equation :(13)εs=given by :(14)Cs=4.1.A sandwich plate capacitive humidity sensor, integrated with a platinum resistance heater, was fabricated using micro electro mechanical system (MEMS) technology. It is composed of a silicon substrate, heating electrode, wet film polyimide sensor and porous gold electrodes. The structure of the humidity sensor is shown in 2 on the surface of the Si substrate as the first insulation layer. The snakelike heater electrode is fabricated on the insulation layer using photolithographic lift-off technology. The fabrication flow and planar structure are shown in The Si substrate with a thickness of 150 μm is (100)-oriented. Thermal oxidation technology is used to generate a layer of dense SiOA photograph of the humidity sensor is shown in 4.2.A humidity generator, dew-point instrument and LCR meter were used to measure the performance of the humidity sensor. A dual-pressure method humidity generator is used. It has the advantage that the humidity can be adjusted over a very wide range at different temperatures, and is stable in a short time, so it can be used to study humidity sensor dynamic characteristics. The device block diagram is shown in The experimental results showed that the humidity sensor has small humidity hysteresis. As shown in In accordance with the results in H̄1 and H̄2 are the two sets of weighted average humidity values, 1σ, 2σ are standard deviations, Hs1 stands for the fusion humidity based on formula H̄ stands for the arithmetic average value and SH stands for the multi-sensor data fusion algorithm's value. One of the experimental data sets is shown in In order to obtain the humidity sensor error, a repeatability experiment was carried out from 0 °C to 40 °C, and the humidity sensor error is about 0.3 pF. According to the output characteristics of the sensor, the single shot trigger was used to change the sensor capacitance output into a fixed frequency pulse width output, then, convert the fixed frequency pulse width output into the voltage output according to capacitor charge and dischare. The humidity generator and dew-point instrument were the used to measure the performance of the radiosonde humidity sensor array. The temperature was kept constant around 20 °C and the humidity increases from 10% RH to 90% RH in 50 min. Four humidity sensor outputs are obtained. According to the position of the four sensors placed, the weight of sensors No. 1 and No. 3 is determined to be 1.2, and the weights of sensors No. 2 sensor and No. 4 is 0.8. In accordance with the results in R = 0.9998, SSE = 0.3528, the result means the actual temperature value and the theoretical temperature value are very close, with small, and successful temperature estimation.In order to ensure the good performance of the humidity sensor at different temperatures, its surface temperature must be maintained in the range of +20 °C to +30 °C. A high and low temperature testing instrument was used to get the relationship between environment temperature and Pulse-Width-Modulation (PWM). The results were given in H−60 °C, H−40 °C, H−20 °C, H0 °C and H+20 °C stand for the processing humidity values at different temperatures using the multi-sensor data fusion method.R−60 °C = 0.9986, SSE−60 °C = 5.43, R−40 °C = 0.9999, SSE−40 °C = 4.08, R−20 °C = 0.9992, SSE−20 °C = 3.125, R0 °C = 0.9994, SSE0 °C = 2.252, R+20 °C = 0.9997, SSE+20 °C = 1.202. The result means the actual humidity value and the theoretical humidity value are close. The SSE becomes gradually smaller as the environment temperature rises, humidity data estimation is satisfactory, and continuous. The designed humidity with a platinum resistance heater effectively solves the sensor condensation problem.Putting the data into the regression equation, we obtained 5.Considering the requirements of the pressure sensor such as wide operating temperature range, low power consumption, small package and low cost, the MS5540 digital pressure sensor with a resolution of 0.1 hPa and detect range of 10 hPa–1,100 hPa, was chosen and its supply power was 2.2 V–3.6 V. Furthermore, the interior of sensor has a temperature compensation circuit, which makes the pressure sensor still possess a good performance even in low temperature condition.6.6.1.The system can be divided into two parts, the first part is data acquisition and transmission, and the second part is data reception and processing. The microwave receiver unit block diagram was shown in 6.2.According to the hardware architecture of the designed radiosonde, the tasks of the whole system are to achieve high altitude detection of the humidity, temperature and pressure, wireless data transmission and information component display on a PC. Therefore, software development of the system includes two parts—radiosonde software design and PC software design. The radiosonde software design idea is as follows: first, initialize the DSP and the GPS, collecting the ambient temperature, then, judge whether or not the humidity need to be heated under some temperature conditions, if it needs to be heated, use controlled PWM to regulate the surface of the humidity sensor; secondly, collect the ambient temperature, humidity, pressure, and read the current GPS data; finally, use the multi-sensor fusion method to process humidity data, and use the microwave transmitting unit to send the meteorological data to the ground receiver system.In order to reduce the influence of the microwave signal on the received data, and to avoid data loss, the meteorological data is composed of frame head, node address, valid date bits, checksum bit and frame end. The data structure is shown in PC software design idea is as follows: first, initialization procedure, set up the serial number and baud rate, then, wait to receive data until the data is received. Judge validity of the data. If it is valid data, store it and plot the curve, if not, delete it and wait for the next valid data. The data structure is shown in 7.Dynamic experiments were carried out at one of the meteorological observation stations in the northeast of China, and the meteorological data was collected, including temperature data, humidity data, pressure data, and so on.7.1.7.2.The humidity value changes gently at the altitude between 1,000 m and 3,000 m. When the altitude is about 4,000 m to 15,000 m, the layer of water vapor content gradually decreased with increasing altitude, and the humidity gradually reduced. As the altitude continues to increase, the humidity value is essentially constant, because of the water vapor in the air is less and constant.8.A capacitive humidity sensor with a platinum resistance heater was developed using MEMS technology, the capacitance of the sensor increased from 100 pF to 150 pF. Using PWM to control the heating power of humidity sensor, the sensor operating temperature is at about +20–+30 °C, which allows capacitance and humidity to exhibit a good linearity with a sensitivity of about 0.375 pF/%RH. The radiosonde sensor array was made of four humidity sensors to collect aloft atmospheric humidity, and enhance the credibility of the humidity data accuracy.R approached to 1, and the SSE was small after the humidity data were processed by the multi-sensor data fusion technology. The actual temperature value was very close to the theoretical one. Such a small error indicates a very successful estimation of the temperature data.Since the multi-sensor data fusion technology has the advantages of fault tolerance, complementary real-time, weighted average and batch estimates were used to process the meteorological data. Static experiments show that Dynamic experiments showed that the radiosonde worked properly in a high altitude environment with characteristics of high sensitivity and rapid response and can accurately reflect the changes of atmospheric data. The humidity sensor array with a platinum resistance heater can effectively solve the sensor condensation problem. In future work, we will focus on radiosonde data repeatability and reliability, and high altitude comparative experiments with the RS92 unit will be carried out to optimize the hardware and software design.


The electrical properties  of the transferred graphene as well as the specific contact resistance of metal contacts onto graphene were investigated by using properly designed test patterns. While a sheet resistance Rsh ≈ 1.7 kΩ/sq and a specific contact resistance ρc ≈ 15 kΩ·μm have been measured for graphene transferred onto SiO2, about 2.3× higher Rsh and about 8× higher ρc values were obtained for graphene on PEN. High-resolution current mapping by torsion resonant conductive atomic force microscopy (TRCAFM) provided an insight into the nanoscale mechanisms responsible for the very high ρc in the case of graphene on PEN, showing a ca. 10× smaller “effective” area for current injection than in the case of graphene on SiO2.Chemical vapour deposition (CVD) on catalytic metals is one of main approaches for high-quality graphene growth over large areas. However, a subsequent transfer step to an insulating substrate is required in order to use the graphene for electronic applications. This step can severely affect both the structural integrity and the electronic properties of the graphene membrane. In this paper, we investigated the morphological and electrical properties of CVD graphene transferred onto SiO Its ele lattice  of graph lattice , and its lattice .Due to its excellent mobility, graphene has been proposed as a channel material in high-frequency devices operating in the 100 GHz to terahertz range . Thanks 5 cm2·V−1·s−1 have been measured on exfoliated graphene flakes suspended between electrodes [2·V−1·s−1 are obtained for flakes on common dielectric substrates [Currently, the most used method of graphene production for basic studies is the mechanical exfoliation of graphite , which wectrodes , whereasbstrates . As a maOther methods, such as epitaxial graphene growth by controlled graphitization of silicon carbide –15 and bConsidering the case of CVD, the two main catalytic metals used for graphene growth are nickel and copper . In the A commonly used method to transfer graphene grown on copper foil onto the target substrate is the use of a resist film deposited on the graphene surface, which is used as a support during the etching of the underlying Cu foil. After the etching process, the graphene membrane attached to the resist scaffold is mechanically attached to the target substrate and the resist is eliminated. There are two crucial points in this transfer technique: (i) promoting the adhesion of graphene onto the target substrate; and (ii) cleaning the transferred graphene from resist residues.The first issue is especially critical, because a bad compatibility between graphene and the substrate typically causes the formation of macroscopic defects (cracks) or folding of the graphene membrane when placed onto the substrate. Several aspects can influence the surface adhesion between graphene and the substrate, including the substrate roughness and the surface energy. Though a complete understanding of this issue has not yet been achieved, it can be argued that, due to the inherent hydrophobic character of graphene, the adhesion of large-area membranes can be favoured on substrates with a similar hydrophobic character.2/H2 or Ar/H2) ambient conditions [Resist and, more generally, polymeric residues adsorbed onto graphene are known to severely degrade graphene transport properties . Howevernditions . Such hiIn this paper, the transfer and electrical properties of CVD-grown graphene on different substrates have been addressed. In particular, two substrates of interest for electronic applications were taken into consideration:2 (300 nm thick) thermally grown on Si, for its large-scale use in microelectronics;SiOpoly or PEN, a transparent polymer analogue to the more common PET, but with stronger mechanical resistance, higher degradation temperature and higher chemical inertness in acid and alkaline conditions, which can be useful for transparent and flexible electronic applications.The electronic properties of the transferred graphene have been characterized both at the macro- and nanoscale, by using properly fabricated test patterns and conductive atomic force microscopy, respectively. This characterization provided an insight into the different electronic properties of graphene transferred to the two kinds of substrates.4/H2 as precursors. In −1) and 2D peak (at ≈2640 cm−1) of the graphitic material. In particular, the high ratio of the 2D versus G peak and the symmetric character of the 2D peak  indicates the presence of a certain density of defects in the as-grown material. Morphology and phase images of as-grown graphene on Cu, obtained by tapping mode atomic force microscopy (AFM), are also reported in Graphene was grown by CVD on ca. 25 μm thick polycrystalline copper foils at a temperature of 1000 °C by using CH2. This oxide thickness was properly selected because it ensures the best optical contrast between bare SiO2 regions and regions coated by the monoatomic thick membrane, due to an effect of constructive optical interference [The graphene membrane was transferred from the Cu foil onto a Si wafer coated by 300 nm thick thermally grown SiOrference .2 typically exhibits a hydrophilic behaviour , before graphene transfer proper surface treatments were performed to achieve a partially hydrophobic character . The chemical status of the SiO2 surface before graphene transfer was also characterized by X-ray photoelectron spectroscopy (XPS) measurements.Since as-grown SiO2) graphene membrane transferred onto SiO2 is shown. Due to the good optical contrast between the graphene-coated and bare SiO2 areas, a homogenous graphene membrane, free from macroscopic cracks, can be observed. Higher resolution morphological analyses of the graphene layer onto SiO2 were carried out by tapping mode AFM. Two representative AFM images at different magnifications are reported in 2 on a crack region extracted from 2 [In d from 2 . Both crd from 2 .2, which is naturally hydrophilic and requires proper treatments to be converted into a hydrophobic surface, contact-angle measurements on the as-received PEN substrate typically yield high values of the contact angle (≈80°), indicating the highly hydrophobic character of this surface. A representative morphological image of the PEN substrate is reported in In contrast to the case of virgin SiOThe homogeneity of graphene membranes on the transparent PEN substrate can be characterized in a straightforward way by optical transmittance microscopy, since a contrast between graphene-coated and uncoated regions arises from the finite absorbance (≈2.7%) of the graphene monolayer. Optical images (not reported) demonstrate the absence of macroscopic cracks and fractures in the graphene transferred onto PEN, which can be explained as a consequence of a very good compatibility between the two materials.2 is reported in W = 200 μm and length L = 100 μm) and different spacing, d, deposited onto a laterally insulated rectangular graphene area. The current–voltage (I–V) characteristics for different distances between adjacent contacts are reported in R, obtained from the slope of each curve, is plotted versus the contact distance. According to the TLM theory [R is related to the metal/graphene contact resistance Rc and to the graphene sheet resistance Rsh according to the relationThe electronic transport properties of the large-area graphene transferred onto the two different substrates have been characterized on the macroscopic scale by electrical measurements on transmission line model (TLM) test structures. An optical microscopy image of a TLM test pattern fabricated in graphene on SiOM theory , R is reRsh = 1.75 ± 0.04 kΩ/sq) and the contact resistance (Rc = 75 ± 6 Ω) contributions have been determined. Since Rc clearly depends on the pad size, the specific contact resistance ρc = Rc·W normalized to the contact width was also evaluated, obtaining a value ρc = 15.1 ± 1.2 kΩ·μm.By linear fitting of the data in 2(300nm)/Si substrate, the n+-doped Si substrate can be employed as global back-gate  and of the sheet resistance (Rsh) on the gate bias was extracted  [2. This doping can probably be ascribed to the adsorbed resist impurities left after transfer. Furthermore, the measured ρc is almost one order of magnitude higher than in the case of the same nickel–gold contacts on graphene exfoliated onto SiO2 [Compared to the typically ambipolar behaviour observed in back-gated FET devices fabricated in graphene exfoliated from HOPG onto SiOve bias) –11, a p-nto SiO2 .Rsh in graphene is related to the hole mobility μp and density p by the following relationThe hole conductance σ = 1 / p has been expressed as the sum of p0, i.e., the doping at Vg = 0, and of the doping induced by the back-gate bias (Cox·Vg/q), with q being the electron charge and Cox= ε0εox/tox the oxide capacitance per unit area.where Vg data with p = 793 ± 18 cm2·V−1·s−1 and p0 = (4.4 ± 0.1) × 1012 cm−2 have been obtained. It is worth noting that the effect of traps at the graphene/SiO2 interface is not accounted for in the determination of μp from p, which is actually reduced with respect to the value induced by the field effect due to carrier trapping, and, consequently, an underestimation of the carrier mobility. Furthermore, the presence of charged traps at the graphene/substrate interface strongly affects the mobility in graphene due to Coulomb scattering [By linear fitting of the experimental σ versus attering ,26, leadRsh and ρc values for graphene on the two substrates (obtained with a back-gate bias Vg = 0 for graphene on SiO2 and without a back-gate bias for graphene on PEN) is reported in A similar macroscopic electrical characterization using TLM structures was performed also in CVD graphene transferred onto PEN. In this case, the sheet resistance and specific contact resistance only were measured, whereas an estimate of mobility and carrier density was not feasible due to the absence of a back gate. A comparison between the Rsh of graphene on PEN is about 2.3× higher than on SiO2, whereas the ρc is about 8× higher. Since the same CVD graphene was used for both samples and similar transfer quality has been achieved on both substrates, these electrical differences can be ascribed to the different kind of interaction between graphene and SiO2 and graphene and PEN. In fact, a van der Waals interaction occurs between graphene and SiO2, whereas it cannot be excluded that other kind of bonds occur locally between graphene and the polymeric substrate, leading to a partial sp3 hybridization of graphene C atoms and, hence, to a local disruption of graphene electronic properties. This idea is supported by the presence of a certain density of defects in the initial graphene (as shown by Raman measurements), that can represent preferential sites for bonding with the polymeric chains.It is worth noting that the 2 and on PEN were characterized by torsion resonance conductive AFM (TRCAFM).In order to get a deeper insight into the mechanisms leading to the different electronic properties of transferred graphene on the two substrates, and, in particular, to the very different specific contact resistance values, the local electrical properties of graphene on SiOTRCAFM is an evolution of the more widely used contact mode conductive atomic force microscopy (CAFM). It is a dynamic scanning probe method based on a conductive tip scanned at close proximity (0.3–3.0 nm) to the sample surface, while oscillating in the torsional mode. The torsion amplitude is used as the feedback signal to measure surface morphology.A dc bias was applied to a macroscopic metal contact deposited onto graphene, and the current locally injected from the nanometric conductive tip into graphene was probed by a high sensitivity (fA) current sensor connected to the tip. In this way, TRCAFM combines the high resolution of dynamic scanning probe microscopy for morphological mapping with the ability for nanoscale-resolution current mapping of CAFM. This operation mode has been demonstrated to be particularly useful to perform high-resolution morphology and current maps in graphene –28.2. In 2 is much flatter than the morphology of graphene on PEN, due to the very different roughness of the substrates. The most interesting aspect is represented by the comparison of the current maps and of the current histograms. Clearly, both histograms exhibit two peaks, but it is worth noting that the integrated percentage of counts under the higher conductivity peak is much higher for graphene on SiO2 (85%) than for graphene on PEN (9%). This striking difference indicates that in the case of graphene on SiO2 most of the area contributes to current injection from the tip to graphene, whereas in the case of graphene on PEN only a small fraction of the area contributes to the current injection. This observation is in close agreement with the difference in the specific contact resistance values obtained from macroscopic TLM measurements. The physical origin of this difference is still the subject of investigation.2 and PEN) and its morphological and electrical properties have been investigated in detail. Using TLM test patterns the electrical properties  of the transferred graphene and the specific contact resistance of metal contacts on graphene were determined. While a sheet resistance Rsh ≈ 1.7 kΩ/sq and a specific contact resistance ρc ≈ 15 kΩ·μm were measured (at Vg = 0 V) for graphene transferred onto SiO2, about 2.3× higher Rsh and about 8× higher ρc values were obtained for graphene on PEN. High-resolution current mapping by torsion resonant conductive atomic force microscopy (TRCAFM) revealed a ca. 10× smaller “effective” area for current injection in the case of graphene on PEN than in the case of CVD graphene transferred on SiO2 ,which is consistent with higher ρc values. These electrical differences could be ascribed also to the different kind of interaction of graphene with SiO2 and PEN. While a van der Waals bond occurs between graphene and SiO2, other kind of bonds can be locally formed between graphene and the polymeric chains of PEN, leading to a partial sp3 hybridization of graphene and, hence, to a local modification of its electronic properties.In conclusion, the transfer of CVD-grown graphene onto different substrates (SiOTapping mode AFM and TRCAFM: Both tapping-mode AFM and torsion resonant conductive atomic force microscopy (TRCAFM) measurements were performed by using a DI3100 microscope with Nanoscope V electronics. For TRCAFM, we used Pt/Ir-coated Si tips with an apex radius of curvature of 10 nm, which were driven in torsional motion at a frequency of 940 kHz.TLM fabrication and electrical characterization: The transmission line model (TLM) test patterns were fabricated on the transferred graphene membranes by using the following procedure. First, rectangular graphene areas were isolated from the external membrane by lithographically defining and opening a rectangular frame in a hard mask resist and by performing graphene etching of the frame by O2 plasma treatments. Subsequently, a set of nickel-gold rectangular contacts were deposited by sputtering and defined by the lift-off method. The contacts had identical geometry (200 µm width and 100 µm length) and the distance between the pairs of adjacent contacts were 20, 20, 40, 60, 80, 100 and 100 µm, respectively. The current–voltage (I–V) characteristics were measured in a Karl-Süss probe station by using a HP 4156B parameter analyzer.Raman spectroscopy: Raman measurements were performed by using a Horiba-Jobin Yvon spectrometer. Spectra were collected in the backscattering configuration with a ≈633 nm laser source and a 100× objective, focusing the excitation light to a ≈1 μm spot.XPS: SiO2 atomic surface composition was determined by X-ray photoelectron analysis (XPS) by using a PHI ESCA/SAM 5600 Multitechnique spectrometer. XPS experiments were carried out with a base pressure of 2 × 10−10 torr. A monochromated Al Kα radiation source (hν = 1486.6 eV) was used, and XPS spectra were collected at various photoelectron angles (relative to the sample surface) in the 20–45° range.


Tuberculosis and sarcoidosis share similarity in histopathologic findings and clinically occur in association with each other occasionally. Tuberculosis should always be ruled out before the diagnosis of sarcoidosis. But, the diagnosis is often complicated, especially in extrapulmonary cases. Here we present a case of bilateral vitreous hemorrhage with uveitis. Ocular sarcoidosis was initially diagnosed based on the characteristic ocular findings, negative results on chest radiography, tuberculosis culture, and polymerase chain reaction of aqueous, as well as simultaneous presence of panda and lambda sign on gallium-67 scans. The ocular condition improved after pars plana vitrectomy and systemic steroid therapy. However, TB lymphadenopathy but no recurrent ocular inflammation was found 6 years later. The patient received anti-TB treatment for 6 months thereafter. The eyes remained silent except cataract progression and glaucoma under two medications during this period. In conclusion, TB could occur coincidently or in association with sarcoidosis, continued follow-up is important for patients with ocular sarcoidosis. Sarcoidosis is a multisystemic, granulomatous disease of unknown etiology that may affect any organ system. It is characterized by the accumulation of T lymphocytes and mononuclear phagocytes with the formation of noncaseating epithelioid granulomas in affected organs . The triA 35-year-old female was referred to our department with severe visual impairment for months. She was quite healthy until 1 year ago when she began to suffer recurrent episodes of uveitis with mutton fat keratic precipitates (KPs) in both eyes. On presentation, visual acuity was counting finger in right eye and hand motion in left eye. Ocular examination showed mild anterior uveitis with mutton fat KPs and dense vitreous hemorrhage in both eyes. Systemic workup including general physical examination, complete blood counting, differential classification, blood biochemical tests, rheumatic factor, antinuclear antibody, human immunodeficiency virus, venereal disease research laboratory test, anticardiolipin antibody, and chest radiography were within normal ranges. Due to persistent vitreous hemorrhage and disabled vision, pars plana vitrectomy was performed in the left eye and then the right eye 2 months later. Sign of peripheral vasculitis with nodular choroid infiltration was noted during operation in both eyes. Aqueous for TB culture and polymerase chain reaction (PCR) was negative. Angiotensin-converting enzyme was not done due to the unavailability in our hospital. Gallium-67 scans showed panda sign of increased uptake in lacrimal glands and lambda sign of lymph nodes in the mediastinum  established an international criteria for the diagnosis of ocular sarcoidosis . The conMycobacterium tuberculosis catalase–peroxidase have renewed interest in mycobacteria as a causative agent in sarcoidosis [Despite the increasing understanding of the immune responses behind the formation and maintenance of the granulomatous process in sarcoidosis, its etiology remained elusive. Mycobacteria have been implicated as a cause of sarcoidosis, although the demonstration of mycobacterial DNA was inconsistent in different reports , 7. Rececoidosis , 3. In oTB could occur coincidently or in association with sarcoidosis, continued follow-up is important for patients with ocular sarcoidosis, even in silent case.


Novel approaches are needed to define subgroups of patients with Idiopathic pulmonary fibrosis (IPF) at risk for acute exacerbations and/or accelerated progression of this generally fatal disease. Progression of disease is an integral component of IPF with a median survival of 3 to 5 years. Conversely, a high degree of variability in disease progression has been reported among series. The characteristics of patients at risk of earlier death predominantly rely on baseline HRCT appearance, but this concept that has been challenged. Disparate physiological approaches have also been taken to identify patients at risk of mortality, with varying results. We hypothesized that the rapid decline in lung function in IPF may be a consequence of an abnormal host response to pathogen-associated molecular patterns (PAMPs), leading to aberrant activation in fibroblasts and fibrosis. Analysis of upper and lower lobe surgical lung biopsies (SLBs) indicated that TLR9, a hypomethylated CpG DNA receptor, is prominently expressed at the transcript and protein level, most notably in biopsies from rapidly progressive IPF patients. Surprisingly, fibroblasts appeared to be a major cellular source of TLR9 expression in IPF biopsies from this group of progressors. Further, CpG DNA promoted profibrotic cytokine and chemokine synthesis in isolated human IPF fibroblasts, most markedly again in cells from patients with the rapidly progressive IPF phenotype, in a TLR9-dependent manner. Finally, CpG DNA exacerbated fibrosis in an in vivo model initiated by the adoptive transfer of primary fibroblasts derived from patients who exhibited rapidly progressing fibrosis. Together, these data suggested that TLR9 activation via hypomethylated DNA might be an important mechanism in promoting fibrosis particularly in patients prone to rapidly progressing IPF. IPF patients exhibit heterogeneous longitudinal behavior that is best defined by using a combination of physiological progression and clinical events. Identifying rapid progression over the first year of follow-up is clinically relevant given ongoing and planned therapeutic trials, which are of approximately one-year duration. Identifying which patients who are likely to experience rapid progression over such a time frame would provide key data in clinical decision-making and in the design of future therapeutic trials, providing an opportunity for personalized approaches to therapy. Unfortunately, baseline clinical, physiological and radiological differences, which identify these subgroups, have been difficult to identify.Identifying biologically relevant differences between IPF patients that remain stable or show slow progression compared to those who rapidly progress is an active area of investigation but to date a detailed understanding of the gene expression pattern in IPF patients segregated into stable or rapidly progressive groups using standard methodology is lacking. Our studies to date suggest this is a promising avenue of investigation given that we have identified a host response gene, TLR9, which is uniquely upregulated in biopsies from rapidly progressing, but not slowly progressing, IPF patients relative to normal biopsies . More imCO or six minute walk performance stratified by baseline six-minute walk desaturation. An FVC decrease > 10% or a DLCO decrease of at least 15% was shown to strongly predict subsequent mortality or rapidly progressing IPF. Those patients who did not show these changes in lung function appeared to have a slower progressing IPF. Together, these data support that longitudinal physiological behavior can be used to segregate IPF patients into groups with differing long-term mortality, and physiological heterogeneity is a strong predictor of longitudinal disease course.A high degree of heterogeneity in longitudinal physiological behavior is noted. In a group of 80 patients with IPF we examined the predictive ability of serial change in FVC over six or twelve months to predict subsequent survival . At six In the placebo arm of a large therapeutic trial, we reported that 36 21.4%) IPF patients died during 72 weeks of follow-up [.4% IPF pCO), acute exacerbation or mortality  and in the interstitial areas of the IPF biopsies. TLR9 expression was present only in morphologically distinct immune cells but was not detected in interstitial areas of histologically normal lung tissue. Thus, these data confirmed that TLR9 protein was prominently expressed in IPF biopsy material, and provided evidence that the increase in TLR9 transcript expression in IPF was due to the expression of this receptor by cell types not normally positive for TLR9.Based on the observation that TLR9 expression was remarkably enhanced in the interstitial areas of biopsies collected from patients affected by IPF, we have further investigated the expression of TLR9 protein in cultured IPF fibroblasts . Using cTo explore whether CpG ODN altered fibrosis in a model of IPF in SCID mice developed in our laboratory ,8, we inIt is becoming increasingly clear that IPF is a designation applied to a group of patients with heterogeneous longitudinal courses. Nearly half of all deaths are due to acute exacerbations superimposed on a chronic, more slowly progressive disease course. Our findings suggest that: 1) IPF patients exhibit variable longitudinal behavior both physiologically and clinically; 2) serial pulmonary function testing in combination with clinically relevant events  can be used to define clinically distinct subgroups of IPF patients; 3) TLR9 is strongly upregulated in IPF biopsies and expressed by IPF fibroblasts (most prominently in rapidly progressive patients); and 4) CpG ODN drives pro-fibrotic cytokines and chemokines in a TLR9-dependent manner strongly supporting the connection between host-environment interactions in pulmonary fibrosis.The authors declare that they have no competing interests.