Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta-analysis.

OBJECTIVES: The primary objective was to perform a systematic review of predictive factors for obstetric anal sphincter injury (OASI) occurrence at first vaginal delivery, with the diagnosis made by ultrasound (US-OASI). The secondary objective was to report on incidence rates of sonographic anal sphincter (AS) trauma, including trauma that was not clinically reported at childbirth, among the studies providing data for our primary objective. METHODS: We conducted a systematic search of MEDLINE, EMBASE, Web of Science, CINAHL, The Cochrane Library and ClinicalTrials.gov databases. Both observational cohort studies and interventional trials were eligible for inclusion. Study eligibility was assessed independently by two authors. Random-effects meta-analyses were performed to pool effect estimates from studies reporting on similar predictive factors. Summary odds ratio (OR) or mean difference (MD) is reported with 95% CI. Heterogeneity was assessed using the I2 statistic. Methodological quality was assessed using the Quality in Prognosis Studies tool. RESULTS: A total of 2805 records were screened and 21 met the inclusion criteria (16 prospective cohort studies, three retrospective cohort studies and two interventional non-randomized trials). Increasing gestational age at delivery (MD, 0.34 (95% CI, 0.04-0.64) weeks), shorter antepartum perineal body length (MD, -0.60 (95% CI, -1.09 to -0.11) cm), labor augmentation (OR, 1.81 (95% CI, 1.21-2.71)), instrumental delivery (OR, 2.13 (95% CI, 1.13-4.01)), in particular forceps extraction (OR, 3.56 (95% CI, 1.31-9.67)), shoulder dystocia (OR, 12.07 (95% CI, 1.06-137.60)), episiotomy use (OR, 1.85 (95% CI, 1.11-3.06)) and shorter episiotomy length (MD, -0.40 (95% CI, -0.75 to -0.05) cm) were associated with US-OASI. When pooling incidence rates, 26% (95% CI, 20-32%) of women who had a first vaginal delivery had US-OASI (20 studies; I2 = 88%). In studies reporting on both clinical and US-OASI rates, 20% (95% CI, 14-28%) of women had AS trauma on ultrasound that was not reported clinically at childbirth (16 studies; I2 = 90%). No differences were found in maternal age, body mass index, weight, subpubic arch angle, induction of labor, epidural analgesia, episiotomy angle, duration of first/second/active-second stages of labor, vacuum extraction, neonatal birth weight or head circumference between cases with and those without US-OASI. Antenatal perineal massage and use of an intrapartum pelvic floor muscle dilator did not affect the odds of US-OASI. Most (81%) studies were judged to be at high risk of bias in at least one domain and only four (19%) studies had an overall low risk of bias. CONCLUSION: Given the ultrasound evidence of structural damage to the AS in 26% of women following a first vaginal delivery, clinicians should have a low threshold of suspicion for the condition. This systematic review identified several predictive factors for this. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Association of self-directed walking with toxicity moderation during chemotherapy for the treatment of early breast cancer.

BACKGROUND: In the field of exercise oncology, there is a need to quantify the potential benefits of moderate, self-directed physical activity during active treatment. In a pooled analysis of three identical single-arm intervention studies, we investigate the association of activity tracker steps with patient-reported toxicities during chemotherapy. METHODS: Women with early breast cancer who were enrolled in the intervention studies reported their symptom severity every 2-3 weeks throughout chemotherapy, and daily steps were documented through a Fitbit activity tracker. Relative risks (RR) and 95% confidence intervals (CI) were calculated using Poisson regression models with robust variance. For outcomes significant in unadjusted models, adjusted RRs were calculated controlling for race, age, and education level. Tracker step cut point (high step, low step) was determined by the means. Cumulative incidence functions of moderate, severe, and very severe (MSVS) symptoms were estimated using the Kaplan-Meier method and compared using a Cox proportional hazard model. RESULTS: In a sample of 283 women, mean age was 56 years and 76% were White. Mean tracker-documented steps/week were 29,625, with 55% walking below the mean (low step) and 45% above (high step). In multivariable analysis, high step patients had lower risk for fatigue [RR 0.83 (0.70, 0.99)] (p = 0.04), anxiety [RR 0.59 (0.42, 0.84)] (p = 0.003), nausea [RR 0.66 (0.46, 0.96)] (p = 0.03), depression [RR 0.59 (0.37, 0.03)] (p = 0.02), and ≥ 6 MSVS symptoms [RR 0.73 (0.54, 1.00)] (p = 0.05) and had 36% lower risk for dose reductions [RR 0.64 (95% CI 0.43, 0.97)] (p = 0.03). CONCLUSION: Self-directed walking at a rate of at least 30,000 steps/week may moderate the severity of treatment side effects during chemotherapy for early breast cancer. TRIAL NUMBERS: NCT02167932, NCT02328313, NCT03761706.

Measurements of pulse rate using facial video cameras from smart devices in patients diagnosed with atrial fibrillation.

Clinical applications of passive long-term heart rate (HR) monitoring in patients with cardiac arrhythmias include adequate drug titration of atrioventricular (AV) nodal drugs and assessment of medical compliance with treatment. A majority of patients treated with beta-blockers, especially patients with atrial fibrillation (AF), require some degree of drug titration during the first 6 months of treatment to ensure that adequate HR control and medicine compliance has been achieved. Failing to achieve adequate rate control in patients with AF can lead to worsening symptoms, heart failure exacerbations, and potentially tachycardia-induced cardiomyopathy. Enabling video-based monitoring during telehealth patient visits could facilitate providers to measure heart rate (HR) without the need for a dedicated home device (smartwatch, SPO2 device, or others). Videoplethysmography (VPG) is a monitoring technology that measures pulse rate by utilizing front-facing cameras embedded in smart devices. VPG provides a remote and contactless cardiac monitoring solution. We conducted a clinical experiment to evaluate the accuracy of VPG in measuring HR while running on two portable devices: Samsung S10 smartphones and S3 tablets. We used a single­lead ECG to measure the heart rate at the time of the VPG recordings in AF patients. We employed the Bland-Altman method to measure the level of agreement between videoplethysmography and ECG-based measurements of HR. The findings reveal that the mean difference in videoplethysmography and ECG-based heart rate was inferior to 1 bpm across the 2 devices with confidence intervals ranging from 3 to 12 BPM. Our facial video-based HR monitoring solution could assist providers in measuring heart rates in their patients with AF during remote telehealth visits.

Thin-Layer-Agar-Based Direct Phenotypic Drug Susceptibility Testing on Sputum in Eswatini Rapidly Detects Mycobacterium tuberculosis Growth and Rifampicin Resistance Otherwise Missed by WHO-Endorsed Diagnostic Tests.

Xpert MTB/RIF rapidly detects resistance to rifampicin (RR); however, this test misses I491F-RR conferring rpoB mutation, common in southern Africa. In addition, Xpert MTB/RIF does not distinguish between viable and dead Mycobacterium tuberculosis (MTB). We aimed to investigate the ability of thin-layer agar (TLA) direct drug-susceptibility testing (DST) to detect MTB and its drug-resistance profiles in field conditions in Eswatini. Consecutive samples were tested in parallel with Xpert MTB/RIF and TLA for rifampicin (1.0 µg/ml) and ofloxacin (2.0 µg/ml). TLA results were compared at the Reference Laboratory in Antwerp with indirect-DST on Löwenstein-Jensen or 7H11 solid media and additional phenotypic and genotypic testing to resolve discordance. TLA showed a positivity rate for MTB detection of 7.1% versus 10.0% for Xpert MTB/RIF. Of a total of 4,547 samples included in the study, 200 isolates were available for comparison to the composite reference. Within a median of 18.4 days, TLA detected RR with 93.0% sensitivity (95% confidence interval [CI], 77.4 to 98.0) and 99.4% specificity (95% CI, 96.7 to 99.9) versus 62.5% (95% CI, 42.7 to 78.8) and 99.3% (95% CI, 96.2 to 99.9) for Xpert MTB/RIF. Eight isolates, 28.6% of all RR-confirmed isolates, carried the I491F mutation, all detected by TLA. TLA also correctly identified 183 of the 184 ofloxacin-susceptible isolates (99.5% specificity; 95% CI, 97.0 to 99.9). In field conditions, TLA rapidly detects RR, and in this specific setting, it contributed to detection of additional RR patients over Xpert MTB/RIF, mainly but not exclusively due to I491F. TLA also accurately excluded fluoroquinolone resistance.

"Watch Me Grow- Electronic (WMG-E)" surveillance approach to identify and address child development, parental mental health, and psychosocial needs: study protocol.

BACKGROUND: The COVID-19 pandemic and the associated economic recession has increased parental psychosocial stress and mental health challenges. This has adversely impacted child development and wellbeing, particularly for children from priority populations (culturally and linguistically diverse (CALD) and rural/regional communities) who are at an already increased risk of health inequality. The increased mental health and psychosocial needs were compounded by the closure of in-person preventive and health promotion programs resulting in health organisations embracing technology and online services. Watch Me Grow- Electronic (WMG-E) - developmental surveillance platform- exemplifies one such service. WMG-E was developed to monitor child development and guide parents towards more detailed assessments when risk is identified. This Randomised Controlled Trial (RCT) aims to expand WMG-E as a digital navigation tool by also incorporating parents' mental health and psychosocial needs. Children and families needing additional assessments and supports will be electronically directed to relevant resources in the 'care-as-usual' group. In contrast, the intervention group will receive continuity of care, with additional in-person assessment and 'warm hand over' by a 'service navigator' to ensure their needs are met. METHODS: Using an RCT we will determine: (1) parental engagement with developmental surveillance; (2) access to services for those with mental health and social care needs; and (3) uptake of service recommendations. Three hundred parents/carers of children aged 6 months to 3 years (recruited from a culturally diverse, or rural/regional site) will be randomly allocated to the 'care-as-usual' or 'intervention' group. A mixed methods implementation evaluation will be completed, with semi-structured interviews to ascertain the acceptability, feasibility and impact of the WMG-E platform and service navigator. CONCLUSIONS: Using WMG-E is expected to: normalise and de-stigmatise mental health and psychosocial screening; increase parental engagement and service use; and result in the early identification and management of child developmental needs, parental mental health, and family psychosocial needs. If effective, digital solutions such as WMG-E to engage and empower parents alongside a service navigator for vulnerable families needing additional support, will have significant practice and policy implications in the pandemic/post pandemic period. TRIAL REGISTRATION: The trial (Protocol No. 1.0, Version 3.1) was registered with ANZCTR (registration number: ACTRN12621000766819 ) on July 21st, 2021 and reporting of the trial results will be according to recommendations in the CONSORT Statement.

Human placental villi contain stromal macrovesicles associated with networks of stellate cells.

Placental function is essential for fetal development and establishing the foundations for lifelong health. The placental villous stroma is a connective tissue layer that supports the fetal capillaries and villous trophoblast. All the nutrients that cross the placenta must also cross the stroma, and yet little is known about this region. This study uses high-resolution three-dimensional imaging to explore the structural complexity of this region within the placental villi. Serial block-face scanning electron microscopy and confocal microscopy were used to image the placental villous stroma in three-dimensions. Transmission electron microscopy (TEM) was used to generate high resolution two-dimensional images. Stereological approaches were used to quantify volumes of stromal constituents. Three-dimensional imaging identified stromal extracellular vesicles, which constituted 3.9% of the villous stromal volume. These stromal extracellular vesicles were ovoid in shape, had a median length of 2750 nm (range 350-7730 nm) and TEM imaging confirmed that they were bounded by a lipid bilayer. Fifty-nine per cent of extracellular vesicles were in contact with a fibroblast-like stellate cell and these vesicles were significantly larger than those where no contact was observed. These stellate cells formed local networks with adherent junctions observed at contact points. This study demonstrates that the villous stroma contains extracellular macrovesicles which are considerably larger than any previously described in tissue or plasma. The size and abundance of these macrovesicles in the villous stroma highlight the diversity of extracellular vesicle biology and their roles within connective tissues.

Alternative observational designs to estimate the effectiveness of one dose of oral cholera vaccine in Lusaka, Zambia.

We conducted a matched case-control (MCC), test-negative case-control (TNCC) and case-cohort study in 2016 in Lusaka, Zambia, following a mass vaccination campaign. Confirmed cholera cases served as cases in all three study designs. In the TNCC, control-subjects were cases with negative cholera culture and polymerase chain reaction results. Matched controls by age and sex were selected among neighbours of the confirmed cases in the MCC study. For the case-cohort study, we recruited a cohort of randomly selected individuals living in areas considered at-risk of cholera. We recruited 211 suspected cases (66 confirmed cholera cases and 145 non-cholera diarrhoea cases), 1055 matched controls and a cohort of 921. Adjusted vaccine effectiveness of one dose of oral cholera vaccine (OCV) was 88.9% (95% confidence interval (CI) 42.7-97.8) in the MCC study, 80.2% (95% CI: 16.9-95.3) in the TNCC design and 89.4% (95% CI: 64.6-96.9) in the case-cohort study. Three study designs confirmed the short-term effectiveness of single dose OCV. Major healthcare-seeking behaviour bias did not appear to affect our estimates. Most of the protection among vaccinated individuals could be attributed to the direct effect of the vaccine.

Laser therapy for urinary incontinence and pelvic organ prolapse: a systematic review.

BACKGROUND: Laser therapy is now being proposed for the treatment of pelvic organ prolapse (POP) and urinary incontinence (UI). OBJECTIVES: To systematically review the available literature on laser therapy for POP and UI. SEARCH STRATEGY: PubMed, Web Of Science and Embase were searched for relevant articles, using a three-concept (POP, UI, laser therapy) search engine composed as (concept 1 OR concept 2) AND concept 3. SELECTION CRITERIA: Only full-text clinical studies in English. DATA COLLECTION AND ANALYSIS: Data on patient characteristics, laser setting, treatment outcome and adverse events were independently collected by two researchers. There was a lack of methodological uniformity so meta-analysis was not possible and the results are presented narratively. MAIN RESULTS: Thirty-one studies recruiting 1530 adult women met the inclusion criteria. All studies showed significant improvement either on UI, POP or both; however the heterogeneity of laser settings, application and outcome measures was huge. Only one study was a randomised controlled trial, two studies were controlled cohort studies. All three were on UI and used standardised validated tools. The risk of bias in the randomised controlled trial was low on all seven domains; the controlled studies had a serious risk of bias. No major adverse events were reported, mild pain and burning sensation were the most commonly described adverse events. CONCLUSIONS: All studies on vaginal and/or urethral laser application for POP and UI report improvement, but the quality of studies needs to be improved. TWEETABLE ABSTRACT: There is weak evidence that laser therapy is effective for urinary incontinence and pelvic organ prolapse #LASER#UI#POP.

DFTB+, a software package for efficient approximate density functional theory based atomistic simulations.

DFTB+ is a versatile community developed open source software package offering fast and efficient methods for carrying out atomistic quantum mechanical simulations. By implementing various methods approximating density functional theory (DFT), such as the density functional based tight binding (DFTB) and the extended tight binding method, it enables simulations of large systems and long timescales with reasonable accuracy while being considerably faster for typical simulations than the respective ab initio methods. Based on the DFTB framework, it additionally offers approximated versions of various DFT extensions including hybrid functionals, time dependent formalism for treating excited systems, electron transport using non-equilibrium Green's functions, and many more. DFTB+ can be used as a user-friendly standalone application in addition to being embedded into other software packages as a library or acting as a calculation-server accessed by socket communication. We give an overview of the recently developed capabilities of the DFTB+ code, demonstrating with a few use case examples, discuss the strengths and weaknesses of the various features, and also discuss on-going developments and possible future perspectives.

Potential of electric bicycles to improve the health of people with Type 2 diabetes: a feasibility study.

AIM: To explore in a feasibility study whether 'e-cycling' was acceptable to, and could potentially improve the health of, people with Type 2 diabetes. METHODS: Twenty people with Type 2 diabetes were recruited and provided with an electric bicycle for 20 weeks. Participants completed a submaximal fitness test at baseline and follow-up to measure predicted maximal aerobic power, and semi-structured interviews were conducted to assess the acceptability of using an electric bicycle. Participants wore a heart rate monitor and a Global Positioning System (GPS) receiver in the first week of electric bicycle use to measure their heart-rate during e-cycling. RESULTS: Eighteen participants completed the study, cycling a median (interquartile range) of 21.4 (5.5-37.7) km per week. Predicted maximal aerobic power increased by 10.9%. Heart rate during electric bicycle journeys was 74.7% of maximum, compared with 64.3% of maximum when walking. Participants used the electric bicycles for commuting, shopping and recreation, and expressed how the electric bicycle helped them to overcome barriers to active travel/cycling, such as hills. Fourteen participants purchased an electric bicycle on study completion. CONCLUSIONS: There was evidence that e-cycling was acceptable, could increase fitness and elicited a heart rate that may lead to improvements in cardiometabolic risk factors in this population. Electric bicycles have potential as a health-improving intervention in people with Type 2 diabetes.

Chilli consumption and the incidence of overweight and obesity in a Chinese adult population.

BACKGROUND: The frequency of spicy food intake has recently been associated with a reduced risk of mortality in the Chinese population. This study aimed to prospectively examine the association between chilli intake and the incidence of overweight/obesity in a Chinese adult population. METHODS: Adults aged 20-75 years in the China Health and Nutrition Survey were followed between 1991 and 2011. Dietary data were collected during home visits using a 3-day food record in 1991, 1993, 1997, 2000, 2004, 2006, 2009 and 2011. Cox regression was used in the analysis. Overweight/obesity was defined as body mass index ⩾25 kg m-2. RESULTS: A total 12 970 adults were followed for a median of 9 years. During 126 884 person-years of follow-up, 3203 subjects developed overweight/obesity. The absolute incidence rate of overweight/obesity was 26.4, 22.3, 24.4 and 20.5 per 1000 person-years among those who consumed no chilli or 1-20, 20.1-50, ⩾50.1 g per day, respectively. Chilli consumption was therefore inversely associated with the incidence of overweight/obesity. After adjusting for age, gender, energy and fat intake, smoking, alcohol drinking and physical activity, those whose cumulative average chilli intake was 0, 1-20, 20.1-50 and ⩾50.1 g per day had a hazard ratio for overweight/obesity of 1.00, 0.81 (95% confidence interval=0.73-0.89), 0.77 (0.69-0.86) and 0.73 (0.63-0.84); P for trend <0.001, respectively. There was no interaction between chilli intake and gender, income, education and residence (urban/rural) in relation to the risk of overweight/obesity. CONCLUSIONS: Chilli intake is inversely associated with the risk of becoming overweight/obese in Chinese adults.

Intracellular signalling pathways: targets to reverse immunosenescence.

Ageing is a very complex process, the result of the dysregulation of multiple systems interacting in many ways. A prominent change occurring with ageing is related to the architecture and functioning of the immune system, viewed commonly as detrimental and termed 'immunosenescence'. However, age-associated changes may also lead to increased function in certain respects, which can be viewed as adaptive. None the less, on balance it is well-recognized that immunosenescence is accompanied by the low-grade inflammation observed commonly in elderly people, which has been dubbed 'inflamm-ageing'. The exact cause and significance of all these changes is not clear, but there is a consensus that they are related to the occurrence of chronic non-infectious age-associated disease, as well as increased susceptibility to infections. Alterations to immune cell signalling may be a prominent cause of malfunctioning immunity. Emerging attempts to reverse immunosenescence have recently targeted the signalling pathways in various different cell types of the immune system. Here, we review and discuss alterations in the signalling pathways of immune cells with ageing and consider current targets and means to modulate altered functions. We discuss the potential dangers as well as the benefits of these interventions, and consider future approaches to this problem.

Patient outcomes and provider perceptions following implementation of a standardized perioperative care pathway for open liver resection.

BACKGROUND: Enhanced recovery after surgery (ERAS) pathways have been associated with improved perioperative outcomes following several surgical procedures. Less is known, however, regarding their use following hepatic surgery. METHODS: An evidence-based, standardized perioperative care pathway was developed and implemented prospectively among patients undergoing open liver surgery between 1 January 2014 and 31 July 2015. Perioperative outcomes, including length of hospital stay, postoperative complications and healthcare costs, were compared between groups of patients who had surgery before and after introduction of the ERAS pathway. Provider perceptions regarding the perioperative pathway were assessed using an online questionnaire. RESULTS: There were no differences in patient or disease characteristics between pre-ERAS (42 patients) and post-ERAS (75) groups. Although mean pain scores were comparable between the two groups, patients treated within the ERAS pathway had a marked reduction in opioid use on the first 3 days after surgery compared with those treated before introduction of the pathway (all P < 0·001). Duration of hospital stay was shorter in the post-ERAS group (median 5 (i.q.r. 4-7) days versus 6 (5-7) days in the pre-ERAS group; P = 0·037) and there was a lower incidence of postoperative complications (1 versus 10 per cent; P = 0·036). Implementation of the ERAS pathway was associated with a 40·7 per cent decrease in laboratory costs (-US $333; -€306, exchange rate 4 January 2016) and a 21·5 per cent reduction in medical supply costs (-US $394; -€362) per patient. Although 91·0 per cent of providers endorsed the ERAS pathway, 33·8 per cent identified provider aversion to a standardized protocol as the greatest hurdle to implementation. CONCLUSION: The introduction of a multimodal ERAS programme following open liver surgery was associated with a reduction in opioid use, shorter hospital stay and decreased hospital costs. ERAS was endorsed by an overwhelming majority of providers.

From inflamm-aging to immune-paralysis: a slippery slope during aging for immune-adaptation.

Aging is accompanied by many physiological changes including those in the immune system. These changes are designated as immunosenescence indicating that age induces a decrease in immune functions. However, since many years we know that some aspects are not decreasing but instead are increasing like the pro-inflammatory activity by the innate immune cells, especially by monocytes/macrophages. Recently it became evident that these cells may possess a sort of memory called trained memory sustained by epigenetic changes occurring long after even in the absence of the initiator aggressor. In this review we are reviewing evidences that such changes may occur in aging and describe the relationship between inflamm-aging and immunosenescence as an adaptation/remodelling process leading on one hand to increased inflammation and on the other to decreased immune response (immune-paralysis) mastered by the innate immune system. These changes may collectively induce a state of alertness which assure an immune response even if ultimately resulting in age-related deleterious inflammatory diseases.

Medication appropriateness tool for co-morbid health conditions in dementia: consensus recommendations from a multidisciplinary expert panel.

BACKGROUND: Medication management for people living with dementia is a complex task as it is unclear what constitutes optimal medication management in this population due to the shifting focus of health priorities and the balance between the benefits and harms of medications. AIM: This study sought expert opinion to create a consensus list to define appropriate medication management of co-morbidities for people with dementia. METHODS: This study used the Delphi technique. We invited multidisciplinary experts in geriatric therapeutics including pharmacists, doctors, nurse practitioners, a patient advocate and a psychologist to participate. Participants were asked to engage into three or more rounds of questioning. Round 1 was a questionnaire comprised of one question defining dementia and seven open-ended questions about appropriate management of co-morbidities in people with dementia. Two investigators qualitatively analysed the responses to questions from Round 1 using thematic analysis. The results of this analysis were provided to participants as statements in the Round 2 survey. The participants were asked to rate their agreement with each statement on a 5-point Likert scale. The median and interquartile range (IQR) were calculated for the responses to each statement. Consensus was pre-specified as an IQR less than or equal to 1. Statements where consensus was not achieved were presented to participants in Round 3. The Round 2 median and IQR values were provided and participants were again asked to rate their agreement with each statement on a 5-point Likert scale. The statements where participants agreed or strongly agreed were included in the Medication Appropriateness Tool for Co-morbid Health conditions in Dementia criteria. RESULTS: Fifty-seven experts agreed to participate in the study, of whom 58% were pharmacists and 36% were medical practitioners. Fifty-five participants completed the Round 1 (95% response rate). A total of 128 statements was included in the Round 2 survey. Consensus was reached on 93 statements in Round 2 (n = 48 responders, 84% response rate) and on 18 statements in Round 3 (n = 43 responders, 75% response rate). The participants reached consensus on 111 of 128 statements. Of these statements, 67 statements were included in the Medication Appropriateness Tool for Co-morbid Health conditions in Dementia criteria. The statements were in the broad themes of preventative medication, symptom management, disease progression, psychoactive medication, treatment goals, principles of medication use, side-effects and medication reviews. DISCUSSION: This research provides consensus-based guidance for clinicians who manage co-morbid health conditions in people with dementia.

Insights into carbon nanotube and graphene formation mechanisms from molecular simulations: a review.

The discovery of carbon nanotubes (CNTs) and graphene over the last two decades has heralded a new era in physics, chemistry and nanotechnology. During this time, intense efforts have been made towards understanding the atomic-scale mechanisms by which these remarkable nanostructures grow. Molecular simulations have made significant contributions in this regard; indeed, they are responsible for many of the key discoveries and advancements towards this goal. Here we review molecular simulations of CNT and graphene growth, and in doing so we highlight the many invaluable insights gained from molecular simulations into these complex nanoscale self-assembly processes. This review highlights an often-overlooked aspect of CNT and graphene formation-that the two processes, although seldom discussed in the same terms, are in fact remarkably similar. Both can be viewed as a 0D â†’ 1D â†’ 2D transformation, which converts carbon atoms (0D) to polyyne chains (1D) to a complete sp(2)-carbon network (2D). The difference in the final structure (CNT or graphene) is determined only by the curvature of the catalyst and the strength of the carbon-metal interaction. We conclude our review by summarizing the present shortcomings of CNT/graphene growth simulations, and future challenges to this important area.

Effect of a serogroup A meningococcal conjugate vaccine (PsA-TT) on serogroup A meningococcal meningitis and carriage in Chad: a community study [corrected].

BACKGROUND: A serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine (PsA-TT, MenAfriVac) was licensed in India in 2009, and pre-qualified by WHO in 2010, on the basis of its safety and immunogenicity. This vaccine is now being deployed across the African meningitis belt. We studied the effect of PsA-TT on meningococcal meningitis and carriage in Chad during a serogroup A meningococcal meningitis epidemic. METHODS: We obtained data for the incidence of meningitis before and after vaccination from national records between January, 2009, and June, 2012. In 2012, surveillance was enhanced in regions where vaccination with PsA-TT had been undertaken in 2011, and in one district where a reactive vaccination campaign in response to an outbreak of meningitis was undertaken. Meningococcal carriage was studied in an age-stratified sample of residents aged 1-29 years of a rural area roughly 13-15 and 2-4 months before and 4-6 months after vaccination. Meningococci obtained from cerebrospinal fluid or oropharyngeal swabs were characterised by conventional microbiological and molecular methods. FINDINGS: Roughly 1·8 million individuals aged 1-29 years received one dose of PsA-TT during a vaccination campaign in three regions of Chad in and around the capital N'Djamena during 10 days in December, 2011. The incidence of meningitis during the 2012 meningitis season in these three regions was 2·48 per 100,000 (57 cases in the 2·3 million population), whereas in regions without mass vaccination, incidence was 43·8 per 100,000 (3809 cases per 8·7 million population), a 94% difference in crude incidence (p<0·0001), and an incidence rate ratio of 0·096 (95% CI 0·046-0·198). Despite enhanced surveillance, no case of serogroup A meningococcal meningitis was reported in the three vaccinated regions. 32 serogroup A carriers were identified in 4278 age-stratified individuals (0·75%) living in a rural area near the capital 2-4 months before vaccination, whereas only one serogroup A meningococcus was isolated in 5001 people living in the same community 4-6 months after vaccination (adjusted odds ratio 0·019, 95% CI 0·002-0·138; p<0·0001). INTERPRETATION: PSA-TT was highly effective at prevention of serogroup A invasive meningococcal disease and carriage in Chad. How long this protection will persist needs to be established. FUNDING: The Bill & Melinda Gates Foundation, the Wellcome Trust, and Médecins Sans Frontères.