RNA G-quadruplexes inhibit translation of the PE/PPE transcripts in Mycobacterium tuberculosis.

The role of RNA G-quadruplexes (rG4s) in bacteria remains poorly understood. High G-quadruplex densities have been linked to organismal stress. Here we investigate rG4s in mycobacteria, which survive highly stressful conditions within the host. We show that rG4-enrichment is a unique feature exclusive to slow-growing pathogenic mycobacteria, and Mycobacterium tuberculosis (Mtb) transcripts contain an abundance of folded rG4s. Notably, the PE/PPE family of genes, unique to slow-growing pathogenic mycobacteria, contain over 50% of rG4s within Mtb transcripts. We found that RNA oligonucleotides of putative rG4s in PE/PPE genes form G-quadruplex structures in vitro, which are stabilized by the G-quadruplex ligand BRACO19. Furthermore, BRACO19 inhibits the transcription of PE/PPE genes and selectively suppresses the growth of Mtb but not Mycobacterium smegmatis or other rapidly growing bacteria. Importantly, the stabilization of rG4s inhibits the translation of Mtb PE/PPE genes (PPE56, PPE67, PPE68, PE_PGRS39, and PE_PGRS41) ectopically expressed in M. smegmatis or Escherichia coli. In addition, the rG4-mediated reduction in PE/PPE protein levels attenuates proinflammatory response upon infection of THP-1 cells. Our findings shed new light on the regulation of PE/PPE genes and highlight a pivotal role for rG4s in Mtb transcripts as regulators of post-transcriptional translational control. The rG4s in mycobacterial transcripts may represent potential drug targets for newer therapies.

C-terminal region of Rv1039c (PPE15) protein of Mycobacterium tuberculosis targets host mitochondria to induce macrophage apoptosis.

Mycobacterium tuberculosis (Mtb) genome possesses a unique family called Proline-Glutamate/Proline-Proline-Glutamate (PE/PPE) gene family, exclusive to pathogenic mycobacterium. Some of these proteins are known to play role in virulence and immune response modulation, but many are still uncharacterized. This study investigated the role of C-terminal region of Rv1039c (PPE15) in inducing mitochondrial perturbations and macrophage apoptosis. Our in-silico studies revealed the disordered, coiled, and hydrophobic C-terminal region in Rv1039c has similarity with C-terminal of mitochondria-targeting pro-apoptotic host proteins. Wild type Rv1039c and C-terminal deleted Rv1039c (Rv1039c-/-Cterm) recombinant proteins were purified and their M. smegmatis knock-in strains were constructed which were used for in-vitro experiments. Confocal microscopy showed localization of Rv1039c to mitochondria of PMA-differentiated THP1 macrophages; and reduced mitochondrial membrane depolarization and production of mitochondrial superoxides were observed in response to Rv1039c-/-Cterm in comparison to full-length Rv1039c. The C-terminal region of Rv1039c was found to activate caspases 3, 7 and 9 along with upregulated expression of pro-apoptotic genes like Bax and Bim. Rv1039c-/-Cterm also reduced the Cytochrome-C release from the mitochondria and the expression of AnnexinV/PI positive and TUNEL positive cells as compared to Rv1039c. Additionally, Rv1039c was observed to upregulate the TLR4-NF-κB-TNF-α signalling whereas the same was downregulated in response to Rv1039c-/-Cterm. These findings suggested that the C-terminal region of Rv1039c is a molecular mimic of pro-apoptotic host proteins which induce mitochondria-dependent macrophage apoptosis and evoke host immune response. These observations enhance our understanding about the role of PE/PPE proteins at host-pathogen interface.

PE/PPE mutations in the transmission of Mycobacterium tuberculosis in China revealed by whole genome sequencing.

OBJECTIVE: This study aims to examine the impact of PE/PPE gene mutations on the transmission of Mycobacterium tuberculosis (M. tuberculosis) in China. METHODS: We collected the whole genome sequencing (WGS) data of 3202 M. tuberculosis isolates in China from 2007 to 2018 and investigated the clustering of strains from different lineages. To evaluate the potential role of PE/PPE gene mutations in the dissemination of the pathogen, we employed homoplastic analysis to detect homoplastic single nucleotide polymorphisms (SNPs) within these gene regions. Subsequently, logistic regression analysis was conducted to analyze the statistical association. RESULTS: Based on nationwide M. tuberculosis WGS data, it has been observed that the majority of the M. tuberculosis burden in China is caused by lineage 2 strains, followed by lineage 4. Lineage 2 exhibited a higher number of transmission clusters, totaling 446 clusters, of which 77 were cross-regional clusters. Conversely, there were only 52 transmission clusters in lineage 4, of which 9 were cross-regional clusters. In the analysis of lineage 2 isolates, regression results showed that 4 specific gene mutations, PE4 (position 190,394; c.46G > A), PE_PGRS10 (839,194; c.744 A > G), PE16 (1,607,005; c.620T > G) and PE_PGRS44 (2,921,883; c.333 C > A), were significantly associated with the transmission of M. tuberculosis. Mutations of PE_PGRS10 (839,334; c.884 A > G), PE_PGRS11 (847,613; c.1455G > C), PE_PGRS47 (3,054,724; c.811 A > G) and PPE66 (4,189,930; c.303G > C) exhibited significant associations with the cross-regional clusters. A total of 13 mutation positions showed a positive correlation with clustering size, indicating a positive association. For lineage 4 strains, no mutations were found to enhance transmission, but 2 mutation sites were identified as risk factors for cross-regional clusters. These included PE_PGRS4 (338,100; c.974 A > G) and PPE13 (976,897; c.1307 A > C). CONCLUSION: Our results indicate that some PE/PPE gene mutations can increase the risk of M. tuberculosis transmission, which might provide a basis for controlling the spread of tuberculosis.

The RXLR effector PpE18 of Phytophthora parasitica is a virulence factor and suppresses peroxisome membrane-associated ascorbate peroxidase NbAPX3-1-mediated plant immunity.

Phytophthora parasitica causes diseases on a broad range of host plants. It secretes numerous effectors to suppress plant immunity. However, only a few virulence effectors in P. parasitica have been characterized. Here, we highlight that PpE18, a conserved RXLR effector in P. parasitica, was a virulence factor and suppresses Nicotiana benthamiana immunity. Utilizing luciferase complementation, co-immunoprecipitation, and GST pull-down assays, we determined that PpE18 targeted NbAPX3-1, a peroxisome membrane-associated ascorbate peroxidase with reactive oxygen species (ROS)-scavenging activity and positively regulates plant immunity in N. benthamiana. We show that the ROS-scavenging activity of NbAPX3-1 was critical for its immune function and was hindered by the binding of PpE18. The interaction between PpE18 and NbAPX3-1 resulted in an elevation of ROS levels in the peroxisome. Moreover, we discovered that the ankyrin repeat-containing protein NbANKr2 acted as a positive immune regulator, interacting with both NbAPX3-1 and PpE18. NbANKr2 was required for NbAPX3-1-mediated disease resistance. PpE18 competitively interfered with the interaction between NbAPX3-1 and NbANKr2, thereby weakening plant resistance. Our results reveal an effective counter-defense mechanism by which P. parasitica employed effector PpE18 to suppress host cellular defense, by suppressing biochemical activity and disturbing immune function of NbAPX3-1 during infection.

Role of PE/PPE proteins of Mycobacterium tuberculosis in triad of host mitochondria, oxidative stress and cell death.

The PE and PPE family proteins of Mycobacterium tuberculosis (Mtb) is exclusively found in pathogenic Mycobacterium species, comprising approximately 8-10 % of the Mtb genome. These emerging virulent factors have been observed to play pivotal roles in Mtb pathogenesis and immune evasion through various strategies. These immunogenic proteins are known to modulate the host immune response and cell-death pathways by targeting the powerhouse of the cell, the mitochondria to support Mtb survival. In this article, we are focused on how PE/PPE family proteins target host mitochondria to induce mitochondrial perturbations, modulate the levels of cellular ROS (Reactive oxygen species) and control cell death pathways. We observed that the time of expression of these proteins at different stages of infection is crucial for elucidating their impact on the cell death pathways and eventually on the outcome of infection. This article focuses on understanding the contributions of the PE/PPE proteins by unravelling the triad of host mitochondria, oxidative stress and cell death pathways that facilitate the Mtb persistence. Understanding the role of these proteins in host cellular pathways and the intricate mechanisms paves the way for the development of novel therapeutic strategies to combat TB infections.

Contributing to health system resilience during pandemics via purchasing and supply strategies: an exploratory system dynamics approach.

BACKGROUND: Health systems worldwide struggled to obtain sufficient personal protective equipment (PPE) and ventilators during the COVID-19 pandemic due to global supply chain disruptions. Our study's aim was to create a proof-of-concept model that would simulate the effects of supply strategies under various scenarios, to ultimately help decision-makers decide on alternative supply strategies for future similar health system related crises. METHODS: We developed a system dynamics model that linked a disease transmission model structure (susceptible, exposed, infectious, recovered (SEIR)) with a model for the availability of critical supplies in hospitals; thereby connecting care demand (patients' critical care in hospitals), with care supply (available critical equipment and supplies). To inform the model structure, we used data on critical decisions and events taking place surrounding purchase, supply, and availability of PPE and ventilators during the first phase of the COVID-19 pandemic within the English national health system. We used exploratory modelling and analysis to assess the effects of uncertainties on different supply strategies in the English health system under different scenarios. Strategies analysed were: (i) purchasing from the world market or (ii) through direct tender, (iii) stockpiling, (iv) domestic production, (v) supporting innovative supply strategies, or (vi) loaning ventilators from the private sector. RESULTS: We found through our exploratory analysis that a long-lasting shortage in PPE and ventilators is likely to be apparent in various scenarios. When considering the worst-case scenario, our proof-of-concept model shows that purchasing PPE and ventilators from the world market or through direct tender have the greatest influence on reducing supply shortages, compared to producing domestically or through supporting innovative supply strategies. However, these supply strategies are affected most by delays in their shipment time or set-up. CONCLUSION: We demonstrated that using a system dynamics and exploratory modelling approach can be helpful in identifying the purchasing and supply chain strategies that contribute to the preparedness and responsiveness of health systems during crises. Our results suggest that to improve health systems' resilience during pandemics or similar resource-constrained situations, purchasing and supply chain decision-makers can develop crisis frameworks that propose a plan of action and consequently accelerate and improve procurement processes and other governance processes during health-related crises; implement diverse supplier frameworks; and (re)consider stockpiling. This proof-of-concept model demonstrates the importance of including critical supply chain strategies as part of the preparedness and response activities to contribute to health system resilience.

Improving compliance with personal protective equipment among anaesthetists through behaviour-changing interventions during the coronavirus disease 2019(COVID-19) pandemic.

Since 2020, the coronavirus disease 2019 (COVID-19) pandemic has seen many changes in our daily infection prevention behaviours so as to reduce healthcare-associated transmission of COVID-19 in patients and healthcare workers. In the early phases of the COVID-19 pandemic of 2020, there was much emphasis on compliant personal protective equipment utilization in the operating theatres (OTs) for COVID-19-positive patients. However, during this period, there was a lack of international validated protocols on the appropriate handling and subsequent storage of personal protective equipment in the context of aerosol-generating procedures in OTs for asymptomatic antigen rapid test (ART)-negative patients. Given the potential for transmission even with a negative ART due to the incubation period, our team developed a checklist of eye protection (e.g. goggles/face shield) and N95 mask handling and storage in non-isolation OTs for these patients. We sought to improve the compliance of best practices from 20% to 80% amongst junior anaesthetists in Singapore General Hospital so as to prevent infection transmission and cross-contamination in the OT through education and behaviour-changing interventions. This quality improvement project took place over 19 weeks from June to October 2020 by our team of anaesthetists and nurse clinicians in the non-isolation OT setting. To analyse the problem, we performed a root cause analysis to understand attitudes and beliefs driving their behaviour. The top 80% of cited root causes for non-compliance then guided prioritization of resources for subsequent behaviour-changing interventions. Using the comprehensive infection control checklist, we conducted several plan-do-study-act cycles while implementing this new checklist amongst junior anaesthetists. A total of 227 assessments of junior anaesthetists were made in the care of asymptomatic ART-negative patients. Compliance with correctly handling goggles post-intubation started out as 33.3% in Week 1, which improved to 78.5% by Week 19. Compliance with goggle storage and face shield disposal started out at 13.6% in Week 1 and increased to 78.6% by Week 19. We attributed this improvement to education and behaviour-changing interventions. This quality improvement project focusing on improving compliance with personal protective equipment utilization during the COVID-19 pandemic in the management of asymptomatic ART-negative patients in non-isolation OTs demonstrated the importance of interventions of education, persuasion, modelling, and training in effecting and sustaining organizational behaviour change in physicians and other healthcare personnel.

Mixed-methods study of medical students' attitudes toward peer physical examinations in Japan.

BACKGROUND: Most Japanese medical schools likely continue to rely on peer physical examination (PPE) as a tool to for teaching physical examination skills to students. However, the attitudes of medical students in Japan toward PPEs have not be identified. Therefore, we evaluated students' attitudes toward PPE in a Japanese medical school as a preparation for developing a PPE policy tailored to the context of Japanese culture. METHODS: We conducted a mixed-methods study with an explanatory sequential approach, in which qualitative data were used to interpret the quantitative findings. Surveys and interviews were conducted with medical students and junior residents at a Japanese university. A total of 63 medical students and 50 junior residents responded to the questionnaire. We interviewed 16 participants to reach theoretical saturation and investigated the attitudes of medical students toward PPE and the themes emerging from the interview data, providing detailed descriptions of the quantitative findings. RESULTS: Female participants were significantly more likely than male participants to report varying degrees of resistance to being a model patient during PPE (male: 59.7%, female: 87%, p < 0.001). Most of the participants who took on the role of patients that involved undressing were males. The participants expected improvements in issues related to the guarantee of freedom to refuse to be a model patient and measures to protect confidentiality. Approximately 22% of the participants reported that they witnessed incidental findings (including variations within the normal range) in front of other students during PPE. CONCLUSIONS: The findings imply that medical students expect high levels of autonomy and confidentiality when volunteering as model patients during PPE. Thus, developing a PPE policy suitable for Japanese culture may be effective in establishing a student-centered PPE environment.

Efficacy of remote audio-visual system versus standard onsite buddy system to monitor the doffing of personal protective equipment during COVID-19 pandemic: An observational study.

OBJECTIVES: Literature states a higher self-contamination rate among healthcare workers (HCWs) while doffing personal protective equipment (PPE). During the Covid-19 pandemic, onsite trained observers were not always available to monitor PPE compliance. The remote audio-visual doffing surveillance (RADS) system has the potential to overcome this limitation. We aimed to compare the efficacy of this real-time RADS system against the onsite buddy system for monitoring the doffing of PPE. METHODS: This prospective, observational study was carried out at our tertiary care centre in northern India. 200 HCWs who cared for Covid-19 patients in the intensive care units/operation theatres were included. Group A included HCWs who performed doffing with the help of an onsite trained observer and group B included HCWs who performed doffing with the RADS system. An independent observer noted the error at any step using the CDC doffing checklist, in both groups. An online questionnaire to analyse the level of satisfaction post-doffing was also surveyed. RESULTS: The proportion of errors committed during doffing was significantly lower in group B compared to group A with a low relative risk of 0.34 (95% CI 0.22-0.51) (p < 0.001) (Figure 1A,B). In both groups, there was no difference in HCWs feedback regarding the ease of the system and fear of committing an error. Though the perceived quality of monitoring was felt better with onsite buddy, the overall confidence rating of being safe after doffing was better with the RADS system. CONCLUSION: Real-time RADS system may be more effective than the onsite buddy system for ensuring the safety of HCWs during doffing PPE. HCWs level of satisfaction related to the ease and anxiety with the monitoring systems were comparable. RADS system can reduce reliance on HCW resources and can integrate well into existing healthcare systems.

Psychological flexibility prospectively predicts COVID-19 PPE use across a two-month interval.

Perceived susceptibility, psychological flexibility and health behaviors (PPE use, social distancing) were measured at two time points spaced 2 months apart during the height of the COVID-19 pandemic and lockdown in the U.S.A (Time 1 April 2020; Time 2 June 2020). Demographic variables were also collected. Data from 151 Mturk workers indicated that Time 1 psychological flexibility significantly predicted PPE use and social distancing. The effect sizes were substantial. Perceived susceptibility was not a significant predictor. Psychological flexibility messaging and interventions could be an important way to increase the likelihood of people performing health protective behaviors to better constrain the continuing COVID-19 outbreak.

Bacterial contamination potential of personal protective equipment itself in dental aerosol-producing treatments.

Personal protective equipment (PPE) has long been a high priority in dental aerosol-producing treatments. Since COVID-19 pandemic, its importance has increased yet again. While importance of PPE in preventing transmission and thus possible infection of pathogens is well known, contamination potential of PPE after treatment itself is less investigated. This review aims to give an overview of the current literature and contamination potential (viral, blood, bacterial) of components of protective equipment itself. The literature search was performed using the Medline database; furthermore, a hand search was conducted. Last search took place on 23 November 2022. Two categories of hygiene-related keywords were formed (category A: mask, face shield, goggles, eyewear, personal protective equipment; category B: contamination, aerosol). Each keyword from one category was combined with all keywords from the other one. In addition, the keyword "dental" was always added. First, a title and abstract screening was performed. Afterward, a full-text analysis was followed for the included studies. A total of 648 search hits were found in the Medline database. 47 were included after title and abstract screening. 22 studies were excluded after full-text analysis, 25 studies were included. The hand search resulted in 4 studies that were included. Bacterial contamination of PPE after treatment has been adequately studied, contamination with blood less. Microorganisms mainly originate from the oral and cutaneous flora; however, a transmission of potential pathogens like Staphylococcus aureus or Escherichia coli was also described. Studies showing transmission pathways starting from PPE and its various components are lacking. No measures have yet been described that fully protect the protective equipment from contamination. There is growing awareness that PPE itself can be a source of pathogen transmission, and thus possible infection. Therefore, not only wearing of protective clothing, but also conscious handling of it is crucial for transmission and possible infection prevention. However, studies showing transmission pathways starting from PPE and its various components are lacking. Several studies have investigated what measures can be taken to protect the protective equipment itself. So far, none of the methods evaluated can prevent contamination of PPE.

A critical process variable-regulated, parameter-balancing auxostat, performed using disposed COVID-19 personal protective equipment-based substrate mixture, yields sustained and improved endoglucanase titers.

Fifty percent of the overall operational expenses of biorefineries are incurred during enzymatic-saccharification processes. Cellulases have a global-market value of $1621 USD. Dearth of conventional lignocelluloses have led to the exploration of their waste stream-based, unconventional sources. Native fungus-employing cellulase-production batches fail to yield sustained enzyme titers. It could be attributed to variations in the enzyme-production broth's quasi-dilatant behavior, its fluid and flow properties; heat and oxygen transfer regimes; kinetics of fungal growth; and nutrient utilization. The current investigation presents one of the first-time usages of a substrate mixture, majorly comprising disposed COVID-19 personal protective-equipment (PPE). To devise a sustainable and scalable cellulase-production process, various variable-regulated, continuous-culture auxostats were performed. The glucose concentration-maintaining auxostat recorded consistent endoglucanase titers throughout its feeding-cum-harvest cycles; furthermore, it enhanced oxygen transfer, heat transfer co-efficient, and mass transfer co-efficient by 91.5, 36, and 77%, respectively. Substrate-characterization revealed that an unintended, autoclave-based organsolv pretreatment caused unanticipated increases in endoglucanase titers. The cumulative lab-scale cellulase-production cost was found to be $16.3. The proposed approach is economical, and it offers a pollution-free waste management process, thereby generating carbon credits.

Poor personal protective equipment practices were associated with heat-related symptoms among Asian healthcare workers: a large-scale multi-national questionnaire survey.

BACKGROUND: It is pertinent to understand the perceptions of healthcare workers (HCWs) with their associated personal protective equipment (PPE) usage and heat strain symptoms experienced to effectively combat the negative effects of heat stress during treatment and care activities. METHODS: We evaluated the associated heat stress perceived by HCWs across Asia and validated a questionnaire on perceptions of heat stress, associated PPE usage, and heat strain symptoms experienced. The questionnaire was administered to 3,082 HCWs in six Asian regions. Factor analyses, including Cronbach's alpha, assessed the questionnaire's validity and reliability. Structural equation modelling analysed the effects of knowledge, attitudes and practices, and heat strain symptoms. RESULTS: The questionnaire was found to be reliable in assessing HCWs' knowledge, and attitudes and practices towards heat stress and PPE usage (both Cronbach's alpha = 0.9), but not heat strain symptoms (Cronbach's alpha = 0.6). Despite knowledge of heat stress, HCWs had negative attitudes and practices regarding PPE usage (ß1 = 0.6, p < 0.001). Knowledge (path coefficient = 0.2, p < 0.001), and negative attitudes and practices (path coefficient = 0.2, p < 0.001) of HCWs towards heat stress and PPE usage adversely affected symptoms experienced. CONCLUSIONS: The questionnaire was not reliable in assessing symptoms. HCWs should, nevertheless, still self-assess their symptoms for early detection of heat strain. To effectively attenuate heat strain, understanding HCWs' attitudes and practices towards PPE usage should guide policymakers in implementing targeted heat management strategies.

Donning and doffing of personal protective equipment for health care workers in a tertiary hospital in China: A simulation study.

The application and removal of personal protective equipment (PPE) by health care workers (HCWs) is pivotal to their health and safety and the comprehensive efficacy of hospital infection control measures. This investigation was orchestrated to elucidate the challenges that HCWs may encounter during the donning and doffing of PPE. A total of 110 participants from a tertiary hospital in China were engaged. The study employed fluorescent markers to mimic the exposure of HCWs to tainted body fluids, quantified the contamination outcomes, and evaluated adherence to procedures for donning and doffing. Factors including gender, educational background, and the timing of the most recent instruction on PPE donning and doffing were found to influence the occurrence of contamination points (p < 0.05). No significant differences were identified in contamination frequency when assessing age, body mass index (BMI), occupation, educational background, positional title, working tenure, and experience in managing respiratory infectious diseases (p > 0.05). Predominant contamination sites for fluorescent marker residue included the shoulder (32.73%), neck (21.82%), forearm (16.36%), chest (12.73%), and abdomen (11.82%), with the shoulder being the most contaminated body part. A majority of HCWs exhibited susceptibility to errors during the removal of protective clothing, boot covers, and gloves. The contamination frequency was observed to be correlated with the timing of the last PPE training, educational background, and gender. In acknowledging the intricacy of PPE removal and the deficiencies in HCWs' removal techniques, there emerges a perpetual necessity to refine training methodologies and perpetuate regular PPE instruction.

Quantification of suppressor effects on breech and action noise from AR-15 pattern firearms and its implications for the protection of human hearing.

Noise from firearms is well known to be harmful to human hearing. This problem has been addressed by various military units through the use of muzzle suppressors. However, as suppressor technology has advanced, shooters report hearing the mechanical action of gas-operated semi-automatic rifles (ArmaLite Rifle Model 15 style aka AR-15) as being louder than the suppressed muzzle noise. This study aims to evaluate if harmful noise is present in the shooter's ear, even when impulse noise emanating from the muzzle is suppressed. To characterize the impulse noise of the firearm action caused by the reciprocation of the bolt carrier group (BCG) and subsequent impact when it returns to battery (the forward locked position), the muzzle of a rifle was placed through a constructed plywood wall, and the noise of the action/breech was measured independently from the muzzle noise. This research finds that the impact of the BCG returning to battery (132 dBZ) has the potential to be harmful to the shooter's hearing even when the noise from the muzzle is effectively suppressed.

Evaluating workplace protection factors (WPFs) of different firefighter PPE interface control measures for select volatile organic compounds (VOCs).

Structural firefighters are exposed to a complex set of contaminants and combustion byproducts, including volatile organic compounds (VOCs). Additionally, recent studies have found structural firefighters' skin may be exposed to multiple chemical compounds via permeation or penetration of chemical byproducts through or around personal protective equipment (PPE). This mannequin-based study evaluated the effectiveness of four different PPE conditions with varying contamination control measures (incorporating PPE interface design features and particulate blocking materials) to protect against ingress of several VOCs in a smoke exposure chamber. We also investigated the effectiveness of long-sleeve base layer clothing to provide additional protection against skin contamination. Outside gear air concentrations were measured from within the smoke exposure chamber at the breathing zone, abdomen, and thigh heights. Personal air concentrations were collected from mannequins under PPE at the same general heights and under the base layer at abdomen and thigh heights. Sampled contaminants included benzene, toluene, styrene, and naphthalene. Results suggest that VOCs can readily penetrate the ensembles. Workplace protection factors (WPFs) were near one for benzene and toluene and increased with increasing molecular weight of the contaminants. WPFs were generally lower under hoods and jackets compared to under pants. For all PPE conditions, the pants appeared to provide the greatest overall protection against ingress of VOCs, but this may be due in part to the lower air concentrations toward the floor (and cuffs of pants) relative to the thigh-height outside gear concentrations used in calculating the WPFs. Providing added interface control measures and adding particulate-blocking materials appeared to provide a protective benefit against less-volatile chemicals, like naphthalene and styrene.

Evaluation of self-contained breathing apparatus (SCBA) weight on firefighter stamina, comfort, and postural stability.

Firefighters wear personal protective equipment to protect them from the thermal and chemical environment in which they operate. The self-contained breathing apparatus (SCBA) provides isolation of the airway from the hazardous fireground. National standards limit SCBA weight, however, integration of additional features could result in an SCBA exceeding the current limit. The purpose of this study was to examine the effects of increased SCBA weight on firefighters' physiological responses, work output, dynamic stability, and comfort. Completion of simulated firefighting activities induced a strong physiological response. Peak oxygen consumption was higher with the lightest SCBA than the heaviest SCBA. Few other physiological differences were noted as SCBA weight increased. Importantly, increased SCBA weight resulted in significantly more negative perceptions by the firefighters and a trend towards significance for the duration of work time prior to reaching volitional fatigue. These results should be considered when assessing changes to existing SCBA weight limits.

Increased SCBA weight above existing national standards resulted in negative perceptions by the firefighters, but not significant physiological changes after two simulated bouts of firefighting activity. SCBA weight had a nearly significant impact on the time firefighters worked before reaching volitional fatigue, with heavier SCBA trending towards decreased working time.

Mycobacterial type VII secretion systems.

Mycobacteria, such as the pathogen M. tuberculosis, utilize up to five paralogous type VII secretion systems to transport proteins across their cell envelope. Since these proteins associate in pairs that depend on each other for transport to a different extent, the secretion pathway to the bacterial surface remained challenging to address. Structural characterization of the inner-membrane embedded secretion machineries along with recent advances on the substrates' co-dependencies for transport allow for the first time more detailed and testable models for secretion.

Exposure and Risk Assessment of Korean Firefighters to PBDEs and PAHs via Fire Vehicle Dust and Personal Protective Equipment.

In this study, the levels of polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) were characterized in firefighters' personal protective equipment (PPE) (i.e., jackets, pants, hoods, and gloves) and vehicle dust wipe samples to assess the exposure and potential risk of firefighters to these combustion-related toxic pollutants. The mean levels of ∑PBDEs in the fire vehicle dust samples (778 and 449 pg/cm2 for pump trucks and command cars, respectively) were significantly higher than those in the private vehicles (31.2 pg/cm2) (Kruskal-Wallis test, p < 0.05), which was similar to the ∑PAH levels (521, 185, and 46.8 pg/cm2 for pump trucks, command cars, and private vehicles, respectively). In the case of firefighters' PPE, the levels of ∑PBDEs and ∑PAHs in used jackets and pants were found to be, respectively, 70- to 2242-folds and 11- to 265-folds higher than those in their unused counterparts. Biomass/petroleum combustion was found to be the main source of PAH contamination in fire vehicle dust and used PPE in the present study. Both carcinogenic and noncarcinogenic risks via vehicle dust ingestion and dermal absorption from wearing of PPE were within permissible limits, although the relative risk evaluation showed that PAH/PBDE absorption via wearing of PPE could pose a higher likelihood of carcinogenic and noncarcinogenic risks than the ingestion of pollutants via fire vehicle dust, warranting the need for appropriate management of firefighters' personal protective ensembles.

Sunlight-driven antibacterial activity of a novel zinc oxide quantum dot and its optimization using Box-Behnken design-A medicament for communicable disease protective wearables.

The current study focuses on microwave-assisted zinc oxide quantum dots synthesis (ZnO-QDs) from zinc oxide bionanocomposite (ZnO-BC) preparation. The novelty lies in the preparation of ZnO-QDs, since the natural elements present in ZnO-BC itself acted as a surface penetration enhancer without using any chemical agent. Under ultraviolet (UV) light ZnO-QDs emitted a blue glow, confirming the fluorescence property. Using Box-Behnken design, the experimental factors of ZnO-QDs were optimized, yielding a positive response of 350 nm absorbance and these results also matched with the UV-visible spectroscopy characterization studies of ZnO-QDs. Using Escherichia coli, the antibacterial activity of ZnO-BC in comparison to ZnO-QDs was determined using the well diffusion method and an inhibition zone ranging from 11 to 23 mm and in the broth assay the OD values were reduced by almost seven and 10 times for ZnO-BC and ZnO-QDs, respectively, when compared to the control (untreated). The antibacterial activity demonstrated that our newly prepared BC and its QDs have superior activity when compared to the standard antibiotics such as ampicillin. This type of nanomaterial can be used as a new bioactive natural material with light-assisted activity for antibacterial coatings in the manufacture of personal protective equipment.