Evaluation of Surgical N95 Respirators Covered With Combinations of Masks and Face Shield

OBJECTIVE

The aim of the study is to evaluate the metabolic demands and internal breathing environments when covering an N95 with a surgical mask, cloth mask, and/or FS.

METHODS

Three N95 models approved by the National Institute for Occupational Safety and Health were evaluated under six covering conditions using the National Institute for Occupational Safety and Health Automated Breathing and Metabolic Simulator. All conditions used one trial with each N95 for six incremental 5-minute work rates. Inhaled oxygen and carbon dioxide concentrations, peak inhaled and exhaled pressures, and inhaled wet-bulb and dry-bulb temperatures were measured continuously and averaged across all work rates and covering conditions.

CONCLUSIONS

Results suggest that metabolic demands and internal breathing environments are significantly impacted by all combinations of coverings tested when compared to N95 only.

Friction Force Adjustment by an Innovative Covering System Applied with Superelastic NiTi Brackets and Wires-An In-Vitro Study

The aim of this study was the investigation of polymeric coverings to adjust frictional forces between V-shaped wires and brackets, both made of superelastic NiTi. Adjustment of frictional forces is relevant for certain stages during orthodontic therapy. Coverings able to generate frictional forces when assembled to such brackets are additively manufactured. Six different internal widths of coverings were examined in three different environments: dry condition at room temperature (RT) or body temperature (BT), or artificial saliva (AS) at RT. The different coverings significantly affected the frictional forces for all media (p < 0.001). A correlation between internal width of the covering and resulting frictional forces was found. BT and dry environment showed the lowest friction forces for all samples. The highest force was found for two covering types at RT in AS, while the remaining four covering types showed the highest values in dry environment (p < 0.001). Friction could, therefore, be adjusted by variation of bracket covering clipped onto brackets, which is useful for orthodontic therapy. Coverings delivering higher friction provide dental anchorage, while coverings with lower friction can be used for tooth movement or purely esthetic reasons. It was shown that the variation of covering width may be used for adjustment of frictional forces.

Current opinion and comparison of surgical procedures for the treatment of primary spontaneous pneumothorax

INTRODUCTION

Although three-port video-assisted thoracoscopic surgery (VATS) is the standard radical treatment for primary spontaneous pneumothorax (PSP), several issues need to be addressed as the postoperative recurrence rate remains relatively high. Although bullectomy is effective in preventing the postoperative recurrence of PSP, recurrent pneumothorax often occurs, requiring additional methods such as pleural covering with absorbable mesh sheets, surgical chemical pleurodesis, pleural abrasion, or pleurectomy. In addition, minimally invasive approaches that exceed three-port VATS are required according to the social demand. These approaches, such as uniportal VATS, reduced port surgery, and needlescopic surgery, have cosmetic merits, lower postoperative pain, and similar surgical results as three-port VATS.

AREAS COVERED

We focused on conventional and novel treatments for PSP in this article.

EXPERT OPINION

Effective methods that prevent postoperative recurrence and minimally invasive approaches will become popular in the near future.

Ethnic identity concealment and disclosure: Contexts and strategies

Ethnic minority group members' responses to their prejudicial treatment can take several forms. One involves identity concealment (e.g., 'passing'). In order to understand such a response, we must explore participants' understandings of the interactional context before them, their meta-perceptions of the identity others ascribe to them, and the varied meanings that identity concealment/non-disclosure may have in that context. Our analysis of interview data (N = 30) obtained with Roma in Hungary reveals diverse forms of, and motivations for, the concealment of their Roma identity. Some participants reported examples of proactive identity concealment, others reported more reactive forms (in which they went along with others' mistaken assumptions concerning their identity). The motivations for identity concealment (whether proactive or reactive) included the desire to: secure material benefits; avoid conflict; take pleasure from seeing others' assumptions blinding them to the reality before them; test (and expose) majority group members' attitudes; allow themselves opportunities to experience the world in new ways. Our analysis highlights the importance of social identity researchers recognizing the diverse motivations for ethnic identity concealment: From the actors' perspective concealment is not always assimilatory, and in some contexts can be experienced as empowering.

Heteronormative gatekeeping when enacting queer research in elementary schools: an autoethnographic perspective

Using authoethnography, the authors analyze how queerphobia and cis/heterosexism shape their research process regarding (LGBTQ)-inclusive empirical work in elementary school spaces. With examples from their own experiences, they show how queerphobic gatekeeping affects site access, negotiations required during data collection, and dissemination of the results to others. The authors argue that, taken together, these forces complicate - if not outright prevent - empirical, school-based research with young children, thereby artificially constraining the knowledge base of the field related to LGBTQ-inclusive education. They offer these analyses as affirmations to those facing similar challenges and as education to those in positions of power to change perceptions of, support of, and responses to queer, school-based educational research.

Polydopamine-Derived Nitrogen-Doped Carbon-Covered Na3V2(PO4)2F3 Cathode Material for High-Performance Na-Ion Batteries

Nitrogen-doped carbon-covered Na₃V₂(PO₄)₂F₃ (NVPF/C-PDPA) composites have been successfully prepared by self-polymerization of dopamine on the NVPF surface and subsequent sintering. The X-ray diffraction results show that the NVPF/C-PDPA has good crystallinity and introducing dopamine does not affect the lattice structure of NVPF. The high-resolution transmission electron microscopy, high-angle annular dark-field images, and energy dispersive X-ray spectroscopy analyses reveal that the NVPF/C-PDPA particles are covered by a complete and uniform covering layer, which is effective at preventing corrosion of NVPF in the electrolyte to greatly increase cycling stability. Furthermore, N-doping into the carbon layer can produce additional active sites to improve the capacity especially the rate capacity. Such a NVPF/C-PDPA electrode delivers a remarkable rate capacity (98.0 mA h g^-1 at 10 C) and superior cycle performance (∼95.8% capacity retention at 10 C after 800 cycles). We believe that this work may be beneficial for accelerating the development of high-performance electrode materials and the commercialization of Na-ion batteries.

The evolutionary ecology of decorating behaviour

Many animals decorate themselves through the accumulation of environmental material on their exterior. Decoration has been studied across a range of different taxa, but there are substantial limits to current understanding. Decoration in non-humans appears to function predominantly in defence against predators and parasites, although an adaptive function is often assumed rather than comprehensively demonstrated. It seems predominantly an aquatic phenomenon-presumably because buoyancy helps reduce energetic costs associated with carrying the decorative material. In terrestrial examples, decorating is relatively common in the larval stages of insects. Insects are small and thus able to generate the power to carry a greater mass of material relative to their own body weight. In adult forms, the need to be lightweight for flight probably rules out decoration. We emphasize that both benefits and costs to decoration are rarely quantified, and that costs should include those associated with collecting as well as carrying the material.