The challenges of hydrogen and metals

The Royal Society Scientific Discussion Meeting ‘The challenges of hydrogen and metals’ was held in Carlton House Terrace, London, UK, on 16–18 January 2017. This is the introductory article to the discussion meeting issue which includes contributed papers and seven discussion papers. Here, we introduce the motivation to hold the Meeting and give a brief overview of the contents. We conclude with acknowledgements. This article is part of the themed issue ‘The challenges of hydrogen and metals’

Development of a multi-layered botmaster based analysis framework

Botnets are networks of compromised machines called bots that come together to form the tool of choice for hackers in the exploitation and destruction of computer networks. Most malicious botnets have the ability to be rented out to a broad range of potential customers, with each customer having an attack agenda different from the other. The result is a botnet that is under the control of multiple botmasters, each of which implement their own attacks and transactions at different times in the botnet. In order to fight botnets, details about their structure, users, and their users motives need to be discovered. Since current botnets require the information about the initial bootstrapping of a bot to a botnet, the monitoring of botnets are possible. Botnet monitoring is used to discover the details of a botnet, but current botnet monitoring projects mainly identify the magnitude of the botnet problem and tend to overt some fundamental problems, such as the diversified sources of the attacks. To understand the use of botnets in more detail, the botmasters that command the botnets need to be studied. In this thesis we focus on identifying the threat of botnets based on each individual botmaster. We present a multi-layered analysis framework which identifies the transactions of each botmaster and then we correlate the transactions with the physical evolution of the botnet. With these characteristics we discover what role each botmaster plays in the overall botnet operation. We demonstrate our results in our system: MasterBlaster, which discovers the level of interaction between each botmaster and the botnet. Our system has been evaluated in real network traces. Our results show that investigating the roles of each botmaster in a botnet should be essential and demonstrates its potential benefit for identifying and conducting additional research on analyzing botmaster interactions. We believe our work will pave the way for more fine-grained analysis of botnets which will lead to better protection capabilities and more rapid attribution of cyber crimes committed using botnets

Theoretical evaluation of the role of crystal defects on local equilibrium and effective diffusivity of hydrogen in iron

Hydrogen diffusion and trapping in ferrite is evaluated by quantum mechanically informed kinetic Monte Carlo simulations in defective microstructures. We find that the lattice diffusivity is attenuated by two to four orders of magnitude due to the presence of dislocations. We also find that pipe diffusivity is vanishingly small along screw dislocations and demonstrate that dislocations do not provide fast diffusion pathways for hydrogen as is sometimes supposed. We make contact between our simulations and the predictions of Oriani's theory of ‘effective diffusivity’, and find that local equilibrium is maintained between lattice and trap sites. We also find that the predicted effective diffusivity is in agreement with our simulated results in cases where the distribution of traps is $\textit{spatially homogeneous}$; in the trapping of hydrogen by dislocations where this condition is not met, the Oriani effective diffusivity is in agreement with the simulations to within a factor of two.We are grateful to the European Commission for Funding under the Seventh Framework Programme, Grant No. 263335, MultiHy (multiscale modelling of hydrogen embrittlement in crystalline materials) and Engineering and Physical Sciences Research Council under the HEmS programme grant EP/L014742

Solution structure of a repeated unit of the ABA-1 nematode polyprotein allergen of ascaris reveals a novel fold and two discrete lipid-binding sites

Parasitic nematode worms cause serious health problems in humans and other animals. They can induce allergic-type immune responses, which can be harmful but may at the same time protect against the infections. Allergens are proteins that trigger allergic reactions and these parasites produce a type that is confined to nematodes, the nematode polyprotein allergens (NPAs). These are synthesized as large precursor proteins comprising repeating units of similar amino acid sequence that are subsequently cleaved into multiple copies of the allergen protein. NPAs bind small lipids such as fatty acids and retinol (Vitamin A) and probably transport these sensitive and insoluble compounds between the tissues of the worms. Nematodes cannot synthesize these lipids, so NPAs may also be crucial for extracting nutrients from their hosts. They may also be involved in altering immune responses by controlling the lipids by which the immune and inflammatory cells communicate. We describe the molecular structure of one unit of an NPA, the well-known ABA-1 allergen of Ascaris and find its structure to be of a type not previously found for lipid-binding proteins, and we describe the unusual sites where lipids bind within this structur

Experimental observation of flow fields around active Janus spheres

The phoretic mechanisms at stake in the propulsion of asymmetric colloids have been the subject of debates during the past years. In particular, the importance of electrokinetic effects on the motility of Pt-PS Janus sphere was recently discussed. Here, we probe the hydrodynamic flow field around a catalytically active colloid using particle tracking velocimetry both in the freely swimming state and when kept stationary with an external force. Our measurements provide information about the fluid velocity in the vicinity of the surface of the colloid, and confirm a mechanism for propulsion that was proposed recently. In addition to offering a unified understanding of the nonequilibrium interfacial transport processes at stake, our results open the way to a thorough description of the hydrodynamic interactions between such active particles and understanding their collective dynamics

HIV-1 Disease Progression Is Associated with Bile-Salt Stimulated Lipase (BSSL) Gene Polymorphism

Background: DC-SIGN expressed by dendritic cells captures HIV-1 resulting in trans-infection of CD4+ T-lymphocytes. However, BSSL (bile-salt stimulated lipase) binding to DC-SIGN interferes with HIV-1 capture. DC-SIGN binding properties of BSSL associate with the polymorphic repeated motif of BSSL exon 11. Furthermore, BSSL binds to HIV-1 co-receptor CXCR4. We hypothesized that BSSL modulates HIV-1 disease progression and emergence of CXCR4 using HIV-1 (X4) variants. Results: The relation between BSSL genotype and HIV-1 disease progression and emergence of X4 variants was studied using Kaplan Meier and multivariate Cox proportional hazard analysis in a cohort of HIV-1 infected men having sex with men (n = 334, with n = 130 seroconverters). We analyzed the association of BSSL genotype with set-point viral load and CD4 cell count, both pre-infection and post-infection at viral set-point. The number of repeats in BSSL exon 11 were highly variable ranging from 10 to 18 in seropositive individuals and from 5-17 in HRSN with 16 repeats being dominant (>80% carry at least one allele with 16 repeats). We defined 16 to 18 repeats as high (H) and less than 16 repeats as low (L) repeat numbers. Homozygosity for the high (H) repeat number BSSL genotype (HH) correlated with high CD4 cell numbers prior to infection (p = 0.007). In HIV-1 patients, delayed disease progression was linked to the HH BSSL genotype (RH = 0.462 CI = 0.282-0.757, p = 0.002) as was delayed emergence of X4 variants (RH = 0.525, 95% CI = 0.290-0.953, p = 0.034). The LH BSSL genotype, previously found to be associated with enhanced DC-SIGN binding of human milk, was identified to correlate with accelerated disease progression in our cohort of HIV-1 infected MSM (RH = 0.517, 95% CI = 0.328-0.818, p = 0.005). Conclusion: We identify BSSL as a marker for HIV-1 disease progression and emergence of X4 variants. Additionally, we identified a relation between BSSL genotype and CD4 cell counts prior to infectio

Assessing weight perception accuracy to promote weight loss among U.S. female adolescents: A secondary analysis

<p>Abstract</p> <p>Background</p> <p>Overweight and obesity have become a global epidemic. The prevalence of overweight and obesity among U.S. adolescents has almost tripled in the last 30 years. Results from recent systematic reviews demonstrate that no single, particular intervention or strategy successfully assists overweight or obese adolescents in losing weight. An understanding of factors that influence healthy weight-loss behaviors among overweight and obese female adolescents promotes effective, multi-component weight-loss interventions. There is limited evidence demonstrating associations between demographic variables, body-mass index, and weight perception among female adolescents trying to lose weight. There is also a lack of previous studies examining the association of the accuracy of female adolescents' weight perception with their efforts to lose weight. This study, therefore, examined the associations of body-mass index, weight perception, and weight-perception accuracy with trying to lose weight and engaging in exercise as a weight-loss method among a representative sample of U.S. female adolescents.</p> <p>Methods</p> <p>A nonexperimental, descriptive, comparative secondary analysis design was conducted using data from Wave II (1996) of the National Longitudinal Study of Adolescent Health (Add Health). Data representative of U.S. female adolescents (N = 2216) were analyzed using STATA statistical software. Descriptive statistics and survey weight logistic regression were performed to determine if demographic and independent (body-mass index, weight perception, and weight perception accuracy) variables were associated with trying to lose weight and engaging in exercise as a weight-loss method.</p> <p>Results</p> <p>Age, Black or African American race, body-mass index, weight perception, and weight perceptions accuracy were consistently associated with the likeliness of trying to lose weight among U.S. female adolescents. Age, body-mass index, weight perception, and weight-perception accuracy were positively associated (<it>p </it>< 0.05) with trying to lose weight. Black/African American subjects were significantly less likely than their White counterparts to be trying to lose weight. There was no association between demographic or independent variables and engaging in exercise as a weight-loss method.</p> <p>Conclusions</p> <p>Findings suggest that factors influencing weight-loss efforts, including age, race, body-mass index, weight perception, and weight-perception accuracy, should be incorporated into existing or new multi-component weight-loss interventions for U.S. adolescent females in order to help reduce the national epidemic of overweight and obesity among U.S. female adolescents.</p

Attitudes and Acceptance of Oral and Parenteral HIV Preexposure Prophylaxis among Potential User Groups: A Multinational Study

BACKGROUND: The use of antiviral medications by HIV negative people to prevent acquisition of HIV or pre-exposure prophylaxis (PrEP) has shown promising results in recent trials. To understand the potential impact of PrEP for HIV prevention, in addition to efficacy data, we need to understand both the acceptability of PrEP among members of potential user groups and the factors likely to determine uptake. METHODS AND FINDINGS: Surveys of willingness to use PrEP products were conducted with 1,790 members of potential user groups (FSWs, MSM, IDUs, SDCs and young women) in seven countries: Peru, Ukraine, India, Kenya, Botswana, Uganda and South Africa. Analyses of variance were used to assess levels of acceptance across different user groups and countries. Conjoint analysis was used to examine the attitudes and preferences towards hypothetical and known attributes of PrEP programs and medications. Overall, members of potential user groups were willing to consider taking PrEP (61% reported that they would definitely use PrEP). Current results demonstrate that key user groups in different countries perceived PrEP as giving them new possibilities in their lives and would consider using it as soon as it becomes available. These results were maintained when subjects were reminded of potential side effects, the need to combine condom use with PrEP, and for regular HIV testing. Across populations, route of administration was considered the most important attribute of the presented alternatives. CONCLUSIONS: Despite multiple conceivable barriers, there was a general willingness to adopt PrEP in key populations, which suggests that if efficacious and affordable, it could be a useful tool in HIV prevention. There would be a willingness to experience inconvenience and expense at the levels included in the survey. The results suggest that delivery in a long lasting injection would be a good target in drug development

Protocol for a cluster randomised trial in Madhya Pradesh, India: community health promotion and medical provision and impact on neonates (CHAMPION2); and support to rural India's public education system and impact on numeracy and literacy scores (STRIPES2).

BACKGROUND: Rural areas of India exhibit high neonatal mortality, and low literacy and numeracy. We assess the effect of a complex package of health interventions on neonatal survival and the effect of out-of-school-hours teaching on children's literacy and numeracy in rural Madhya Pradesh. METHODS/DESIGN: This is a cluster-randomised controlled trial with villages (clusters) receiving either a health (CHAMPION2) or education (STRIPES2) intervention. Building on the design of the earlier CHAMPION/STRIPES trial, villages receiving the health intervention are controls for the education intervention and vice versa. The clusters are 196 villages in Satna district, Madhya Pradesh, India: each is at least 5 km from a Community Health Centre, has a population below 2500, and has at least 15 children eligible for the education intervention. The participants in CHAMPION2 are resident married women younger than 50 years of age who had not undergone a family planning operation, provided they are enumerated pre-randomisation or marry a man enumerated pre-randomisation. The participants in STRIPES2 are resident children born 16 June 2010 to 15 June 2013, not in school before the 2018-2019 school year and intending to enrol in first grade in 2018-2019 or 2019-2020. DISCUSSION: In CHAMPION2, the NICE Foundation will deliver a 3.5-year programme comprising Accredited Social Health Activists or village health workers and midwives promoting health knowledge and providing antenatal, postnatal, and neonatal healthcare; community mobilisation; referrals to appropriate government health facilities; and a health education campaign. In STRIPES2, the Pratham Education Foundation will deliver a programme of village-based, before/after school support focusing on literacy and numeracy. As controls, the CHAMPION2 control villages will receive the usual health services (plus the STRIPES2 intervention). STRIPES2 control villages will receive the usual education services (plus the CHAMPION2 intervention). The primary outcome in CHAMPION2 is neonatal mortality. Secondary outcomes include antenatal, delivery, immediate neonatal and postnatal care practices, maternal mortality, stillbirths, early neonatal deaths, perinatal deaths, health knowledge, hospital admissions, maternal blood transfusions, and cost effectiveness. The primary outcome in STRIPES2 is a composite literacy and numeracy test score. Secondary outcomes include separate literacy and numeracy scores, reported school enrolment and attendance, parents' engagement with children's learning, and cost effectiveness. Independent research and implementation teams will conduct the trial. Trial Steering and Data Monitoring Committees, with independent members, will supervise the trial. TRIAL REGISTRATION: Clinical Trial Registry of India: CTRI/2019/05/019296. Registered on 23 May 2019. http://www.ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=31198&EncHid=&modid=&compid=%27,%2731198det%27