879 research outputs found

    The static and dynamic response of SU-8 electrothermal microgrippers of varying thickness

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    This work presents an investigation into the effect on dynamic response of SU-8 microgrippers due to varying thickness, and subsequent validation via COMSOL Multiphysics simulations and thermal camera profiling during actuation. The tweezer-like microgrippers can easily manipulate, with a high degree of control, cells and particles with diameters as small as 10 μm, without using an impractical operating voltage or generating excessive heat. However, in order to fully exploit the versatility of the devices, their response characteristics must be fully understood as material and/or dimension parameters change. Therefore an investigation took place to determine the effects of device thickness on functionality of the device, including the drive current required to actuate the gripper and the speed of actuation. Furthermore, an infrared camera was used to characterise the thermal response of the device. Finally, a simulation of the temperature profile and deflection dimension has been developed in order to verify the findings and further investigate and predict the effects of design variations

    Synthesis and electrochemical characterization of Si/TiO2/Au composite anode: Efficient oxygen evolution and hydroxyl radicals generation

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    This paper describes the photoelectrochemical properties of a novel composite anode composed of a 200 nm Au-Sb ohmic contact/300 μm n-Si wafer/20 nm TiO2 /120 nm Au grid. By connecting the Au ohmic contact to the gold grid via a power supply, holes thermally or photochemically generated in the Si are launched to the TiO2 surface where they are converted to •OH radicals. We show that the Si/TiO2/Au composite anode can be efficiently employed in the oxygen evolution reaction and prove that the anode generates hydroxyl radicals (using p-nitrosodimethylaniline as a probe). Potential applications include the photoelectrocatalytic oxidation of organic contaminants, water splitting, and organic electro-synthesis

    Trait‐based approaches reveal fungal adaptations to nutrient‐limiting conditions

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    The dependency of microbial activity on nutrient availability in soil is only partly understood, but highly relevant for nutrient cycling dynamics. In order to achieve more insight on microbial adaptations to nutrient limiting conditions, precise physiological knowledge is needed. Therefore, we developed an experimental system assessing traits of 16 saprobic fungal isolates in nitrogen (N) limited conditions. We tested the hypotheses that (1) fungal traits are negatively affected by N deficiency to a similar extent and (2) fungal isolates respond in a phylogenetically conserved fashion. Indeed, mycelial density, spore production and fungal activity (respiration and enzymatic activity) responded similarly to limiting conditions by an overall linear decrease. By contrast, mycelial extension and hyphal elongation peaked at lowest N supply (C:N 200), causing maximal biomass production at intermediate N contents. Optimal N supply rates differed among isolates, but only the extent of growth reduction was phylogenetically conserved. In conclusion, growth responses appeared as a switch from explorative growth in low nutrient conditions to exploitative growth in nutrient‐rich patches, as also supported by responses to phosphorus and carbon limitations. This detailed trait‐based pattern will not only improve fungal growth models, but also may facilitate interpretations of microbial responses observed in field studies

    Structural and solution speciation studies on selected [Cu(NN)(OO)] complexes and an investigation of their biomimetic activity, ROS generation and their cytotoxicity in normoxic, hypoxic and anoxic environments in MCF-7 breast cancer-derived cells

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    Reactive oxygen species(ROS) generation with subsequent DNA damage is one of the principle mechanisms of action assigned to copper-based anticancer complexes. The efficacy of this type of chemotherapeutic may be reduced in the low oxygen environment of tumours. In this study the cytotoxicity of three complexes, [Cu(dips)(phen)] (1), [Cu(ph)(phen)]·2H2O (2) and [Cu(ph)(bpy)]·H2O (3) (disp: 3,5-diisopropylsalicylate, phen: 1,10- phenanthroline, ph: phthalate, bpy: 2,2′-bipyridyl) were assessed for anticancer activity in the breast-cancer derived MCF-7 line under normoxic, hypoxic and anoxic conditions. In an immortalised keratinocyte HaCaT cell line, the cytotoxicity of complexes 2 and 3 was significantly reduced under both normoxic and hypoxic conditions, whilst the cytotoxicity of complex 1 was increased under hypoxic conditions. The ability of the complexes to generate ROS in the MCF-7 cell line was evaluated as was their ability to act as superoxide dismutase(SOD) and catalase mimics using a yeast cell assay. ROS generation was significant for complexes 2 and 3, less so for complex 1 though all three complexes had SOD mimetic ability. Given the ternary nature of the complexes, solution speciation studies were undertaken but were only successful for complex 3, due to solubility issues with the other two complexes. The concentration distribution of various species, formed in aqueous solution, was evaluated as a function of pH and confirmed that complex 3 is the dominant species at physiological pH in the mM concentration range. However, as its concentration diminishes, it experiences a progressive dissociation, leading to the formation of binary complexes of bpy alongside unbound phthalate. © 2023 The Author

    Учебная история болезни по внутренним болезням и военно-полевой терапии

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    ВНУТРЕННИЕ БОЛЕЗНИВОЕННО-ПОЛЕВАЯ ТЕРАПИЯИСТОРИЯ БОЛЕЗНИМЕТОДИЧЕСКИЕ УКАЗАНИЯМетодические указания учат студентов правильно оформлять историю болезни пациента

    Students as co-creators of teaching approaches, course design and curricula: implications for academic developers

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    Within higher education, students’ voices are frequently overlooked in the design of teaching approaches, courses and curricula. In this paper we outline the theoretical background to arguments for including students as partners in pedagogical planning processes. We present examples where students have worked collaboratively in design processes along with the beneficial outcomes of these examples. Finally we focus on some of the implications and opportunities for academic developers of proposing collaborative approaches to pedagogical planning

    Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

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    The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio

    Technology-Supported Storytelling (TSST) Strategy in Virtual World for Multicultural Education

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    Learning culture through stories is an effective way for multicultural education, since stories are one of the most powerful and personal ways that we learn about the world. Storytelling, the process of telling stories, is a form of communication and a universal expression of culture. With the development of technology, storytelling emerges out of diverse ways. This study explores the storytelling in virtual worlds for multicultural education, and devises a Technology-Supported storytelling (TSST) strategy by examining and considering the characteristics of virtual worlds which could be incorporated into the storytelling, and then uses this strategy to teach Korean culture to students with different culture background. With this innovative TSST strategy in virtual world, this study expects to provide a guide to practice for teaching multicultural in digital era

    Sociodemographic and clinical correlates of physical therapy utilization in adults with symptomatic knee osteoarthritis

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    Background. Physical therapy is essential for conservative management of symptomatic knee osteoarthritis (OA). However, physical therapy utilization data are limited for knee OA. Objective. The purpose of this study is to identify correlates of physical therapy utilization among adults with symptomatic knee OA. Design. The design consisted of secondary analysis using baseline data from a randomized controlled trial of 350 adults with physician-diagnosed symptomatic knee OA. Methods. Patients completed baseline surveys regarding demographics, pain, function, medical history, and prior physical therapy utilization for symptomatic knee OA. Multivariable logistic regression identified correlates of physical therapy utilization, with models adjusted for body mass index and age. Interactions of race and sex with all other characteristics were evaluated. Results. One hundred and eighty-one patients (52%) reported prior physical therapy utilization. Factors independently associated with increased odds of physical therapy utilization were female sex (odds ratio [OR] =3.06, 95% CI = 1.58-5.93), bachelor degree or higher degree (OR = 2.44, 95% CI = 1.15-5.16), prior knee injury (OR = 1.86, 95% CI = 1.08-3.19), and duration of knee OA symptoms (OR = 2.16, 95% CI = 1.09-4.29 for > 5-10 years; OR = 2.11, 95% CI = 1.10-4.04 for > 10 years). Whites who had received a joint injection were > 3 times as likely to have utilized physical therapy (OR = 3.69, 95% CI = 1.94-7.01); this relationship did not exist for non-whites who had received joint injections. Limitations. A sample enrolled in an exercise study may limit generalizability. Self-report of physical therapy may misclassify utilization. It cannot be determined whether lack of utilization resulted from lack of referral or from patients choosing not to attend physical therapy. Conclusion. Physical therapy is underutilized to manage symptomatic knee OA. Women and those with a bachelor degree or higher degree, prior knee injury, and longer duration of knee OA symptoms were more likely to have used therapy previously. Differences by race in the link between joint injection and physical therapy utilization may reflect a reduced likelihood of referral and decreased use of health interventions for symptomatic knee OA among non-whites, or both
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