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HYPOTHESIS: Phase change slurries (PCS) have emerged as a promising class of oil-in-water emulsions for energy applications, but stability remains an issue. Pickering phase change slurries (PPCS) stabilized solely by nanoparticles could offer enhanced stability. We hypothesize that stability in PPCS can be achieved by tuning environmental variables of salinity and temperature. EXPERIMENTS: A paraffin-based PPCS stabilized using fumed silica nanoparticles was developed and assessed under varying NaCl concentrations (up to 150 mM) and temperatures (up to 70 °C). Extended-DLVO modeling, confocal, and cryogenic electron microscopy analyzed the silica-paraffin interactions. Rheological experiments examined the impact of effective volume fraction, thermal expansion, and salinity on the viscosity and shear stability of PPCS. The stability of the resulting formulation was assessed under high pressure and temperature conditions. FINDINGS: Increased salinity did not change the packing density of the silica at the oil-water interface (82% ± 6%) but did increase the adsorbed layer thickness and network formation, enhancing the formulation's resistance to shear-induced instability. A critical volume fraction of 0.51 ± 0.01 was identified, beyond which viscosity increased significantly. The resulting formulations remained stable under high pressures and temperatures, regardless of salinity. These findings offer insights into the variables affecting PPCS properties, assisting in designing stable PPCS formulations for diverse applications.
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Purpose: The present study aimed to design a quantitative tool to evaluate the comfort and usability of working at height safety harnesses. Methods: This cross-sectional study was conducted in both qualitative and quantitative sections in 2022. The research steps included field interviews, an expert panel, and compiling the questionnaires for assessing the comfort and usability of the harness. The items of tools were designed based on the qualitative part of the research and review of the literature. The face and content validity of the instrument were assessed. Its reliability was also evaluated using the test-retest method. Results: Two tools were developed including a comfort questionnaire with 13 questions and a usability questionnaire with 10 questions. The Cronbach's alpha coefficients of these instruments were 0.83 and 0.79, respectively. Additionally, the content and face validity indices were 0.97 and 3.89 for the comfort questionnaire and 0.991 and 4 for the usability questionnaire, respectively. Conclusions: The designed tools showed appropriate validity and reliability and could be used to evaluate the comfort and usability of safety harnesses. On the other hand, the criteria used in the designed tools could be employed in user-centered harness designs.
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OBJECTIVE: Despite the recent use of computed tomography scan and diagnostic laparoscopy, acute appendicitis is still highly misdiagnosed. Timely diagnosis of acute appendicitis is more crucial in children and elderly patients because of vague symptoms and rapid progression to perforation in these age groups, which may result in high rates of morbidity and mortality. The aim of the present study was to find the diagnostic values of procalcitonin and interleukin 6 (IL-6) for diagnosing acute appendicitis in our center. MATERIAL AND METHODS: Patients who were suspected of acute appendicitis and who were referred to the emergency department of a tertiary care urban hospital in 2016 were enrolled in the study. A 5 mL blood sample was obtained from each patient before appendectomy and was examined for procalcitonin and IL-6. Then, the resected specimen of the appendix was studied by a pathologist, and a definite diagnosis was made. RESULTS: Eighty patients including 53 (66.3%) men who underwent appendectomy were enrolled in the study. The diagnosis of acute appendicitis was histopathologically confirmed in 60 (75%) patients including 18, 20, and 22 patients with inflammatory, suppurative, and gangrenous/perforated appendicitis, respectively. The sensitivity and specificity of procalcitonin versus IL-6 for diagnosing acute appendicitis were 65% and 80% vs. 76% and 55%, respectively. The sensitivity and specificity of concurrent procalcitonin and IL-6 for diagnosing acute appendicitis were 95% and 55%, respectively. CONCLUSION: Our study suggests that parallel measurement of procalcitonin and IL-6 decreases unnecessary negative appendectomies.
ABSTRACT
We describe the utilization of distraction osteogenesis in the free fibular microvascular bone graft to the mandible for increasing bone height for future osseointegrated dental implants. Successful reconstruction of a resected mandible requires restoration of both function and esthetic form. Although current reconstructive techniques restore anterior-posterior and lateral projection, often the graft's vertical height is not sufficient for the placement of osseointegrated dental implants and subsequent oral prosthesis. The patient was a sixteen-year-old male who was found to have a large desmoplastic fibroma of the left mandible, which was resected. The defect was successfully restored with a free fibular microvascular bone graft and reconstruction plate. Nevertheless, the patient had persistent problems with mastication and it was decided to perform a segmental osteotomy of the neomandible. Two internal vertical distraction devices were then placed in the mandible. The appliances were then activated five days postoperative, twice a day, for a total of 14 days. At that time 1.5 cm of distraction had occurred and the patient was placed in a consolidation phase for four months. The patient then had sufficient bone height and was restored with 8 osseointegrated dental implants.
