Thermal Perception of Ventilation Changes in Full-Face Motorcycle Helmets: Subject and Manikin Study

We report the effects of full-face motorcycle helmet ventilation systems on heat, airflow, noise, and comfort perception for ventilation changes on the scalp. Eight subjects (aged 28.0 ± 5.4 years) underwent two experimental trials at ambient temperatures of 23.7 ± 0.4°C or 27.5 ± 0.3°C. In each trial, the thermally equilibrated subjects underwent two examination phases, during which four different helmets were assessed at wind speeds of 39.2 ± 1.9 km h−1 and 59.3 ± 1.4 km h−1. Vent-induced heat loss in the scalp ranged from −6.1 to 6.1 W, corresponding to vents being closed or opened, respectively. Perception of vent-induced changes was assessed immediately after the change. We find that the vent-induced heat loss, the subject, and the helmet are the most important response factors. In addition, comparison of two helmets with similar vent-induced heat loss suggests that internal airflow patterns may be important in explaining the observed perception difference

The Effect of Two Sock Fabrics on Perception and Physiological Parameters Associated with Blister Incidence: A Field Study

The goal of the present study was to investigate differences in perception and skin hydration at the foot of two sock fabrics with distinct moisture properties in a realistic military setting. Thirty-seven military recruits wore two different socks (PP: 99.6% polypropylene and 0.4% elastane, and BLEND: 50% Merino-wool, 33% polypropylene, and 17% polyamide), one on each foot. Measurements were carried out after a daily 6.5-km march on 4 days. Each participant rated temperature, dampness, friction, and comfort for each foot. On a daily selection of participants, skin hydration was measured on three sites of both feet using a corneometer, and moisture content of the socks was determined. BLEND was rated to be cooler, less damp, and more comfortable (P < 0.05). Two out of three skin sites were drier for BLEND than PP (P < 0.05). Moreover, BLEND stored 2.9 ± 0.3 times more moisture compared to PP. Thus, under the present conditions, socks such as BLEND are to be preferred over polypropylene sock

The Effect of Two Sock Fabrics on Physiological Parameters Associated with Blister Incidence: A Laboratory Study

The goal of the present study was to investigate physiological effects, mainly at the level of the foot, of two sock fabrics with distinct moisture properties. Twelve participants wore two different socks, one on each foot. The following two sock types were used: PP: 99.6% polypropylene and 0.4% elastane and BLEND: 50% Merino wool, 33% polypropylene, and 17% polyamide. The participants walked three times on a treadmill at 5 km h−1, with no gradient for the first and third phase and a 10% upward inclination for the second walking phase. The microclimate temperature between the boot and foot was measured during walking. Preceding and following the walking phases, additional measurements were carried out at the level of the foot, i.e. skin temperature and skin hydration on three locations and skin friction between the posterior surface of the calcaneus and a glass plate. In addition, the moisture absorption of boots and socks was determined. Differences between the sock fabrics were found for weight gain and microclimate temperature: (i) PP tended to hold less water compared to BLEND, (ii) the boot's microclimate temperature resulted in larger values for BLEND measured at the dorsal surface at the level of the third metatarsal, and (iii) warmer microclimates of the boot were measured for PP compared to BLEND at the distal anterior end of the tibia. The established differences in moisture behavior of both socks did not result in detectable differences in parameters measured on the skin of the foo

Tailoring Fibre Structure Enabled by X-ray Analytics for Targeted Biomedical Applications

The rising interest in designing fibres via spinning techniques combining the properties of various polymeric materials into advanced functionalised materials is directed towards targeted biomedical applications such as drug delivery, wearable sensors or tissue engineering. Understanding how these functional polymers exhibit multiscale structures ranging from the molecular level to nano-, micro-and millimetre scale is a key prerequisite for their challenging applications that can be addressed by a non-destructive X-ray based analytical approach. X-ray multimodalities combining X-ray imaging, scattering and diffraction allow the study of morphology, molecular structure, and the analysis of nano-domain size and shape, crystallinity and preferential orientation in 3D arrangements. The incorporation of X-ray analytics in the design process of polymeric fibers via their nanostructure under non-ambient conditions (i.e. temperature, mechanical load, humidity…) allows for efficient optimization of the fabrication process as well as quality control along the product lifetime under operating environmental conditions. Here, we demonstrate the successful collaboration between the laboratory of Biomimetic Textiles and Membranes and the Center of X-ray Analytics at Empa for the design, characterisation and optimisation of advanced functionalised polymeric fibrous material systems

Prediction of steam burns severity using raman spectroscopy on ex vivo porcine skin

Skin burns due to accidental exposure to hot steam have often been reported to be more severe than the ones occurring from dry heat. While skin burns due to flames or radiant heat have been thoroughly characterized, the mechanisms leading to steam burns are not well understood and a conundrum still exists: can second degree burns occur without destruction of the epidermis, i.e. even before first degree burns are detected? Skin permeability is dependent both on temperature and on the kinetic energy of incoming water molecules. To investigate the mechanism underlying the injuries related to steam exposure, we used porcine skin as an ex vivo model. This model was exposed to either steam or dry heat before measuring the skin hydration via confocal Raman microspectroscopy. The results show that during the first minute of exposure to steam, the water content in both the epidermis and dermis increases. By analyzing different mechanisms of steam diffusion through the multiple skin layers, as well as the moisture-assisted bio-heat transfer, we provide a novel model explaining why steam burns can be more severe, and why steam can penetrate deeper and much faster than an equivalent dry heat

Nylon-6/chitosan core/shell antimicrobial nanofibers for the prevention of mesh-associated surgical site infection

The state-of-the-art hernia meshes, used in hospitals for hernia repair, are predominantly polymeric textile-based constructs that present high mechanical strength, but lack antimicrobial properties. Consequently, preventing bacterial colonization of implanted prosthetic meshes is of major clinical relevance for patients undergoing hernia repair. In this study, the co-axial electrospinning technique was investigated for the development of a novel mechanically stable structure incorporating dual drug release antimicrobial action. Core/shell structured nanofibers were developed, consisting of Nylon-6 in the core, to provide the appropriate mechanical stability, and Chitosan/Polyethylene oxide in the shell to provide bacteriostatic action. The core/shell structure consisted of a binary antimicrobial system incorporating 5-chloro-8-quinolinol in the chitosan shell, with the sustained release of Poly(hexanide) from the Nylon-6 core of the fibers. Homogeneous nanofibers with a "beads-in-fiber" architecture were observed by TEM, and validated by FTIR and XPS. The composite nanofibrous meshes significantly advance the stress-strain responses in comparison to the counterpart single-polymer electrospun meshes. The antimicrobial effectiveness was evaluated in vitro against two of the most commonly occurring pathogenic bacteria; S. aureus and P. aeruginosa, in surgical site infections. This study illustrates how the tailoring of core/shell nanofibers can be of interest for the development of active antimicrobial surfaces

Fatores prognósticos em câncer de cólon localmente avançado tratado com ressecção extendida

The impact of clinical, pathologic, and surgical variables on the postoperative morbidity, mortality, and survival of patients undergoing extended resections of colon carcinoma were evaluated. METHODS: The medical records of 95 patients who underwent extended resections for colon carcinoma between 1953 and 1996 were reviewed. In all cases, in addition to colectomy, 1 or more organs and/or structures were resected en bloc due to a macroscopically based suspicion of tumor invasion. The clinical, pathologic, and surgical parameters were analyzed. Overall survival rates were analyzed according to the method of Kaplan and Meier. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: Eighty-six patients were treated by curative surgeries and the remaining by palliative resections. Invasion of the organs and/or adjacent structures and regional lymph nodes was found microscopically in 48 and 31 patients, respectively. The median follow-up without postoperative mortality was 47.7 months. The 5-year overall survival rates was 52.6%. The 5-year overall survival rates for patients undergoing curative and palliative surgeries was 58.3% and 0%, respectively. The mean survival time in the palliative surgery group was 3.1 months. Multivariate analysis showed that Karnofsky performance status was strongly related to the risk of postoperative complications (P = .01), and postoperative deaths were associated with the type of surgery and Karnofsky performance status at the time of admission (P = .001). CONCLUSIONS: Some patients with locally advanced colon adenocarcinomas undergoing extended resections have a 5-year overall survival rates of 58.3%. Patients could benefit from palliative-intent procedures, but these measures should cautiously be indicated and avoided in patients with low Karnofsky performance status due to high rates of postoperative mortality and poor survival.Foi avaliado o impacto de variáveis clínicas, patológicas e cirúrgicas na morbidade e mortalidade pós operatórias de pacientes submetidos à ressecção extendida de carcinoma do cólon. MÉTODOS: Prontuários médicos de 95 pacientes submetidos á ressecção extendida de carcinoma de cólon entre os anos de 1953 e 1996 foram revisados. Em todos os casos, além de colectomia, um ou mais órgãos e/ou estruturas foram ressecados em bloco devido á suspeição de invasão tumoral macroscópica. As variáveis clínicas, patológicas e cirúrgicas foram analizadas. As taxas de sobrevida global foram analizadas de acordo com o método de Kaplan and Meier. A análise multivariada foi realizada empregando-se o modelo de risco proporcional de Cox. RESULTADOS: Oitenta e seis pacientes foram tratados com cirurgia curativa e o restante com ressecção paliativa. Invasão microscópica de órgãos e/ou estruturas adjacentes e linfonodos regionais foi encontrada em 48 e 31 pacientes respectivamente. O tempo de seguimento mediano, sem mortalidade pós operatória, foi de 47.7 meses. A taxa de sobrevida global em 5 anos foi de 52.6%. A taxa de sobrevida global para pacientes submetidos à cirurgia curativa e paliativa foi de 58.3% e zero, respectivamente. A sobrevida mediana no grupo de pacientes com cirurgia paliativa foi de 3.1 meses. A análise multivariada mostrou que a performance status de Karnofsky fortemente correlacionou com risco de complicações pós operatórias (p=0.01), e que o risco de morte pós operatória estava associada com o tipo de cirurgia e a performance status de Karnofsky na admissão (p=0.001) CONCLUSÕES: Pacientes com adenocarcinoma de cólon localmente avançados submetidos à ressecção extendida têm taxa de sobrevida global em 5 anos de 58.3% Este tipo de cirurgia pode ser empregada com intuito paliativo, mas deve ter indicação criteriosa e ser evitada em pacientes com baixa performance status de Karnofsky devido às altas taxas de mortalidade pós operatória e baixa sobrevida

A novel inactivated virus system (InViS) for a fast and inexpensive assessment of viral disintegration.

The COVID-19 pandemic has caused considerable interest worldwide in antiviral surfaces, and there has been a dramatic increase in the research and development of innovative material systems to reduce virus transmission in the past few years. The International Organization for Standardization (ISO) norms 18,184 and 21,702 are two standard methods to characterize the antiviral properties of porous and non-porous surfaces. However, during the last years of the pandemic, a need for faster and inexpensive characterization of antiviral material was identified. Therefore, a complementary method based on an Inactivated Virus System (InViS) was developed to facilitate the early-stage development of antiviral technologies and quality surveillance of the production of antiviral materials safely and efficiently. The InViS is loaded with a self-quenched fluorescent dye that produces a measurable increase in fluorescence when the viral envelope disintegrates. In the present work, the sensitivity of InViS to viral disintegration by known antiviral agents is demonstrated and its potential to characterize novel materials and surfaces is explored. Finally, the InViS is used to determine the fate of viral particles within facemasks layers, rendering it an interesting tool to support the development of antiviral surface systems for technical and medical applications

Assessment of compression forces in a digitally modified short leg cast for pressure injury risk monitoring in healthy children

Introduction: Casting is an essential treatment for neuro-orthopedic conditions in children with cognitive, sensory, and communicational disabilities. However, a main side-effect is the development of pressure injuries resulting in additional (wound) therapies and prolongation of the hospital stay. The primary aim of our study was to investigate the potential of objective pressure measurements in casts to assess the risk for pressure injury development. Methods: Five pediatric healthy participants were included in this study. We measured the global and the local compression force at body sites prone to pressure injury development for different body positions and the transfer in-between in a cast equipped with pressure sensors. These conditions resulted in partial or full body weight loading. Results and discussion: The global maximum compression force was affected significantly by body postures with partial and full loading of the cast and during transfer. The local compression force significantly correlated with the global compression force at the heel and instep area. In conclusion, the integration of sensing technologies into casts bears a high potential for early recognition of critical conditions inside the cast and inducing preventive measures in the at-risk population