Exposure of thermoplastics to methanol–gasoline blends: A material compatibility study

Alcohols are increasingly being looked upon as the most viable alternative to the conventional sources of energy. Methanol is the first member of the alcohol family and can be easily synthesized from syngas. It is an attractive blend to gasoline due to its advantageous properties. There is a necessity to make sure that the infrastructure is ready to adapt these alternative fuels. Hence, the aim of this study is to assess the degradation of widely used thermoplastics in fuel tanks, pipes, and the fuel injection system, namely, polytetrafluoroethylene (PTFE), polyethyleneterephthalate (PET), and high density polyethylene (HDPE) post exposure to methanol–gasoline blends (P100, M15, and M30) for a period of 4, 10, and 30 days. The effects of the exposure were examined by comparing changes in gain/loss of mass, hardness, elongation, and tensile strength. The surface morphology changes of the polymeric coupons were characterized by scanning electron microscopy and their elemental analysis was done by energy dispersive X-ray spectroscopy. The studied materials were found to gain mass in the order HDPE > PTFE >PET. The decrease in hardness was found to be more in HDPE followed by PTFE and PET. PTFE and PET showed reduction in strength but an increase in tensile strength was observed for HDPE post exposure to fuel blend. Highest change in elongation was found in HDPE followed by PTFE and PET. The changes were found to be the least in P100 followed by M15 and maximum in M30 blends for all immersion periods.

Awareness and Use of Post-exposure Prophylaxis for HIV Prevention Among Men Who Have Sex With Men: A Systematic Review and Meta-Analysis

Background: The use of post-exposure prophylaxis (PEP) is effective in reducing HIV risk, but it is underused by men who have sex with men (MSM) due to certain psychological and sociostructural factors. This article assessed the awareness and use of PEP among MSM in an effort to increase the visibility and uptake of PEP among at-risk populations.Methods: We conducted a systematic literature search of the PubMed, Web of Science, PsycINFO, and Google Scholar electronic databases. Studies were screened for inclusion, and relevant data were abstracted, assessed for bias, and synthesized. Pooled effect estimates were calculated using random effects meta-analysis, meta-regression and subgroup analysis, and a qualitative review and risk of bias assessment were performed (PROSPERO, CRD42019123815).Results: Twenty eligible studies involving 12,579 MSM were included in the meta-analysis. The pooled estimate of the proportions of MSM who were aware of PEP was modest at 59.9% (95% CI: 50.5~68.7) and that of MSM who previously used PEP was very low at 4.9% (95% CI: 2.4~9.8). PEP awareness showed no clear change over time, while PEP use significantly changed over time. Multiple factors affected awareness, including educational attainment, race/ethnicity, levels of HIV stigma, access to condoms, and so on. Many factors could potentially impede or facilitate the use of PEP, such as income, lack of PEP information, and partnership.Conclusion: We observed that PEP is an underused HIV prevention strategy among MSM and that once MSM become aware of PEP, the majority are willing to use it if they are supported appropriately in terms of a range of individual, social, and structural barriers.Systematic Review Registration: http://www.cdr.york.ac.uk/prospero, PROSPERO [CRD42019123815].

Post-Exposure Prophylaxis and Methamphetamine Use among Young Sexual Minority Men: The P18 Cohort Study

Methamphetamine use is associated with increased risk of HIV infection among young sexual minority men (SMM). Post-exposure prophylaxis (PEP) is an effective strategy for individuals who are exposed to HIV, but there is limited research about PEP use among young SMM and its relationship with methamphetamine use. This study analyzes the association between ever PEP use and recent methamphetamine use among young SMM in New York City, using cross-sectional data from the P18 Cohort Study (n = 429). Multivariable logistic regression models were used to assess the association between methamphetamine use and ever PEP use. Compared with those who had not used methamphetamine in the last 6 months, young SMM who did use methamphetamine were significantly more likely to have ever used PEP (AOR = 6.07, 95% CI: 2.10–16.86). Young SMM who had ever used PrEP had 16 times higher odds of ever using PEP (AOR = 16, 95% CI: 7.41–35.95). Those who completed bachelor’s degrees were 61% less likely to have ever used PEP (AOR = 0.39, 95% CI: 0.17–0.88). These data suggest that methamphetamine use could increase the risk of HIV infection, highlighting the critical need to target interventions for young SMM who use methamphetamine and are more likely to engage in unprotected intercourse.

BNT162b2 post-exposure-prophylaxis against COVID-19

Background: During the COVID-19 pandemic, post-exposure-prophylaxis is not a practice. Following exposure, only patient isolation is imposed. Moreover, no therapeutic prevention approach is applied. We asked whether evidence exists for reduced mortality rate following post-exposure-prophylaxis. Methods: To estimate the effectiveness of post-exposure-prophylaxis, we obtained data from the Israeli Ministry of Health (MoH) registry. The study population consisted of Israeli residents aged 12 years and older, identified for the first time as PCR-positive for SARS-CoV-2, between December 20th, 2020 (the beginning of the vaccination campaign) and October 7th, 2021. We compared 'recently injected' patients - that proved PCR-positive on the same day or on one of the five consecutive days after first vaccination (representing an unintended post-exposure-prophylaxis), to unvaccinated control group. Results: Among Israeli residents identified PCR-positive for SARS-CoV-2, 11,690 were found positive on the day they received their first vaccine injection (BNT162b2) or on one of the 5 days thereafter. In patients over 65 years, 143 deaths occurred among 1413 recently injected (10.12%) compared to 280 deaths among the 1413 unvaccinated (19.82%), odd ratio (OR) 0.46 (95% confidence interval (CI), 0.36 to 0.57; P<0.001). The most significant reduction in the death toll was observed among the 55 to 64 age group, with 8 deaths occurring among the 1322 recently injected (0.61%) compared to 43 deaths among the 1322 unvaccinated control (3.25%), OR 0.18 (95% CI, 0.07 to 0.39; P<0.001). Conclusion: Post-exposure-prophylaxis is effective against death in COVID-19 infection. Israeli MoH Registry Number: HMO-0372-20

Biologic Responses to House Dust Mite Exposure in the Environmental Exposure Unit

Introduction: Allergic rhinitis (AR) is an inflammatory disease of the nasal mucosa that can be modeled using Controlled Allergen Exposure Facilities (CACF). Recently, we clinically validated the house dust mite (HDM) Environmental Exposure Unit (EEU) facility. In the current study, we aimed to assess biological responses in the blood following HDM exposure in the HDM-EEU.Methods: Fifty-five participants passed a screening visit, where they provided consent and completed a skin prick test (SPT), then attended a modest or higher HDM exposure session. Baseline and post-exposure blood samples were collected. Complete blood counts with differentials were measured, and isolated serum was used to determine Dermatophagoides farinae- and Dermatophagoides pteronyssinus-specific IgE (sIgE) and cytokine concentrations (IL-4, IL-5, IL-6, IL-10, IL-13, TNF-α).Results: HDM-allergic participants had significantly greater SPT wheal sizes than healthy controls. sIgE concentrations were significantly greater in allergic participants, with a strong correlation between Dermatophagoides farinae and Dermatophagoides pteronyssinus. Serum eosinophil counts were significantly decreased post-exposure for allergic participants. White blood cell, neutrophil, and lymphocyte counts were significantly increased for both allergic and non-allergic participants post-exposure. Serum IL-13 concentrations were significantly reduced post-exposure in allergics while TNF-α was significantly reduced in non-allergics.Conclusion: The HDM-EEU is a useful model for investigating biologic mechanisms of HDM-induced AR. Allergic participants produced measurable biological changes compared to healthy controls following allergen exposure, specifically with serum expression of eosinophils and related markers, namely IL-5, which promotes the proliferation and differentiation of eosinophils, and IL-13, a cytokine released by eosinophils. The exact mechanisms at play require further investigation.

Bioavailability of Inhaled Or Ingested PFOA Adsorbed To House Dust

Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; lung, liver and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a Cmax at 3 h post exposure. The Cmax following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in plasma, liver and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation- or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to approximately 54-68% and >80% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicate that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that might have accumulated in rats.

Reversion of Ebolavirus Disease from a Single Intramuscular Injection of a pan-Ebolavirus Immunotherapeutic

Intravenous administration (IV) of antiviral monoclonal antibodies (mAbs) is challenging due to limited resources for performing infusions during an ongoing epidemic. An ebolavirus therapeutic administered via intramuscular (IM) injection would reduce these burdens and allow rapid treatment of exposed individuals during an outbreak. Here, we demonstrate how MBP134, a two mAb pan-ebolavirus cocktail, reverses the course of Sudan ebolavirus (SUDV/Gulu) disease with a single IV or IM dose in non-human primates (NHPs) as far as five days post-exposure. Furthermore, we investigated the utility of adding half-life extension mutations to the MBP134 mAbs, ultimately creating a half-life extended cocktail designated MBP431. MBP431 demonstrated an extended serum half-life in vivo and offered complete or significant protection with a single IM dose delivered as a post-exposure prophylactic (PEP) or therapeutic in NHPs challenged with EBOV. These results support the use of MBP431 as a rapidly deployable IM medical countermeasure against every known ebolavirus.

Electromagnetic Field Controlled Domain Wall Displacement for Induced Strain Tailoring in Batio3-Epoxy Nanocomposite: Development of A Contact-Less Active Toughening Mechanism

Failure in an epoxy polymer composite material is prone to initiate by the coalescence of microcracks in its polymer matrix. As such, matrix toughening via addition of a second phase as rigid or/and rubber nano/micro-particles is one of the most popular approaches to improve the fracture toughness across multiple scales in a polymer composite, which dissipates fracture energy via deformation mechanisms and microcracks arrest. Few studies have focused on tailorable and variable toughening, so-called ‘active toughening’, mainly suggesting thermally induced strains which offer slow and irreversible toughening due to polymer’s poor thermal conductivity. The research presented in the current article has developed an instantaneous, reversible active toughening composite based upon contact-less introduction of a microscopic compressive extrinsic strain field via remote electromagnetic radiation. Quantification of the extrinsic strain evolving in the composite with the microwave energy has been conducted using in-situ real-time fibre optic sensing. A theoretical constitutive equation correlating the exposure energy to micro-strains has been developed, with its solution validating the experimental data and describing their underlying physics. The research has utilised functionalised dielectric ferroelectric nanomaterials, barium titanate (BaTiO3), as a second phase dispersed in an epoxy matrix, able to introduce microscopic electro-strains to their surrounding rigid epoxy subjected to an external electric field (microwaves, herein), as result of their domain walls dipole displacements. Epoxy Araldite LY1564, a diglycidyl ether of bisphenol A (DGEBA) associated with the curing agent Aradur 3487 were embedded with the BaTiO3 nanoparticles. The silane coupling agent for the nanoparticles’ surface functionalisation was 3-glycidoxypropyl trimethoxysilane (3-GPS). Hydrogen peroxide (H2O2, 30%) and acetic acid (C2H4O2, 99.9%) used as functionalisation aids, and the ethanol (C2H6O, 99.9%) used for BaTiO3 dispersion. Firstly, the crystal microstructure of the functionalised nanoparticles and the thermal and dielectric properties of the achieved epoxy composite materials have been characterised. It has been observed that the addition of the dielectric nanoparticles has a slight impact on the curing extent of the epoxy. Secondly, the surface-bonded fibre bragg grating (FBG) sensors have been employed to investigate the real-time variation of strain and temperature in the epoxy composites exposed to microwaves at 2.45 GHz and at different exposure energy. The strains developed due to the in-situ exposure at composite, adhesive and their holding fixture material were evaluated using the FBG. The domain wall induced extrinsic strains were distinguished from the thermally induced strains, and found that the increasing exposure energy has an instantaneously increasing effect on the development of compressive strains. Post-exposure Raman spectra showed no residual field in the composite indicating no remnant strain field examined under microwave powers < 1000 W, thus suggesting a reversible strain introduction mechanism, i.e. the composite retaining its nominal properties post exposure. The dielectric composite development and quantifications presented in this article proposes a novel active toughening technology for high-performance composite applications in numerous sectors.

Spatial distribution of anti-rabies post-exposure treatments associated with the decentralization process in Belo Horizonte, 2007 to 2011

Cases of canine attacks on people are reported because of the proximity of the dog to the households in several Brazilian cities. In the present study, we aim to evaluate post-exposure anti-rabies treatments with canine accidents between the years 2007 to 2011 in Belo Horizonte - MG. Duly notified data were obtained from the National System of Notifiable Diseases (SINAN). The spatial characteristics of the cases during the period of the study referred to the neighborhoods and the nine sanitary districts of the municipality of Belo Horizonte - MG. For georeferencing and spatial analysis, we used the software Maporama to identify the coordinates and the Geographic Information System ArcGIS for mapping. Considering the 6.153 prophylactic services that were georeferenced, the Norte, Venda Nova, Leste, and Centro Sul regions were highlighted due to the higher frequency of registered cases. It is suggested that an integrative action focused on canine population control, health education and epidemiological surveillance studies could contribute to the reduction of canine aggression cases.