3,711 research outputs found

    Compression Molded Composite Component

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    The following final design report outlines the design and fabrication of a carbon fiber compression molded sunglasses case. It intends to guide the development of a future lab activity for a composites undergraduate course at Cal Poly – San Luis Obispo. The activity aims to support an educational investigation in out-of-autoclave composites manufacturing methods, such as compression molding, which offer some key benefits over autoclave molding. The methodology behind the creation of a conceptual design, an initial prototype, and a final product is laid out in detail below

    Odorant normative data for use in olfactory memory experiments: Dimension selection and analysis of individual differences

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    The present study reports normative ratings for 200 food and non-food odors. One hundred participants rated odors across measures of verbalisability, perceived descriptive ability,context availability, pleasantness, irritability, intensity, familiarity, frequency, age of acquisition, and complexity. Analysis of the agreement between raters revealed that four dimensions, those of familiarity, intensity, pleasantness, and irritability, have the strongest utility as normative data. The ratings for the remaining dimensions exhibited reduced discriminability across the odor set and should therefore be used with caution. Indeed, these dimensions showed a larger difference between individuals in the ratings of the odors. Familiarity was shown to be related to pleasantness, and a non-linear relationship between pleasantness and intensity was observed which reflects greater intensity for odors that elicit a strong hedonic response. The suitability of these data for use in future olfactory study is considered, and effective implementation of the data for controlling stimuli is discussed

    Metabolic changes in summer active and anuric hibernating free-ranging brown bears (ursus arctos)

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    The brown bear (Ursus arctos) hibernates for 5 to 6 months each winter and during this time ingests no food or water and remains anuric and inactive. Despite these extreme conditions, bears do not develop azotemia and preserve their muscle and bone strength. To date most renal studies have been limited to small numbers of bears, often in captive environments. Sixteen free-ranging bears were darted and had blood drawn both during hibernation in winter and summer. Samples were collected for measurement of creatinine and urea, markers of inflammation, the calcium-phosphate axis, and nutritional parameters including amino acids. In winter the bear serum creatinine increased 2.5 fold despite a 2-fold decrease in urea, indicating a remarkable ability to recycle urea nitrogen during hibernation. During hibernation serum calcium remained constant despite a decrease in serum phosphate and a rise in FGF23 levels. Despite prolonged inactivity and reduced renal function, inflammation does not ensue and bears seem to have enhanced antioxidant defense mechanisms during hibernation. Nutrition parameters showed high fat stores, preserved amino acids and mild hyperglycemia during hibernation. While total, essential, non-essential and branched chain amino acids concentrations do not change during hibernation anorexia, changes in individual amino acids ornithine, citrulline and arginine indicate an active, although reduced urea cycle and nitrogen recycling to proteins. Serum uric acid and serum fructose levels were elevated in summer and changes between seasons were positively correlated. Further studies to understand how bears can prevent the development of uremia despite minimal renal function during hibernation could provide new therapeutic avenues for the treatment of human kidney disease

    Determination of steroid estrogens in wastewater by high performance liquid chromatography-tandem mass spectrometry

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    This paper discusses the requirement for, and presents an analytical procedure for, the determination of four unconjugated steroid hormones and a conjugated steroid (estrone-3-sulfate) in wastewaters. The method quantifies the steroids by LC/MS/MS following solid phase extraction and a two stage clean-up procedure. Samples were extracted using C18 cartridges and eluates were then purified by gel permeation chromatography, followed by a further clean-up step on an aminopropyl cartridge. The limits of detection achieved were 0.2 ng l-1 for estriol, 17β-estradiol and 17α-ethinylestradiol, and 0.1 ng l-1 for estrone and the conjugate. The robustness of the method was demonstrated by achieving recoveries of >83% for all steroids in settled sewage and final effluent samples with relative standard deviations of 0.5 - 12%. The method was used to analyse a range of samples from a wastewater treatment works in south east England which demonstrated a >80% removal for estrone, estradiol and estriol with little impact on concentrations of ethinylestradiol or the conjugate

    Altered Regulation of Renal Sodium Transporters in Salt-Sensitive Hypertensive Rats Induced by Uninephrectomy

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    Uninephrectomy (uNx) in young rats causes salt-sensitive hypertension (SSH). Alterations of sodium handling in residual nephrons may play a role in the pathogenesis. Therefore, we evaluated the adaptive alterations of renal sodium transporters according to salt intake in uNx-SSH rats. uNx or sham operations were performed in male Sprague-Dawley rats, and normal-salt diet was fed for 4 weeks. Four experimental groups were used: sham-operated rats raised on a high-salt diet for 2 weeks (CHH) or on a low-salt diet for 1 week after 1 week's high-salt diet (CHL) and uNx rats fed on the same diet (NHH, NHL) as the sham-operated rats were fed. Expression of major renal sodium transporters were determined by semiquantitative immunoblotting. Systolic blood pressure was increased in NHH and NHL groups, compared with CHH and CHL, respectively. Protein abundances of Na+/K+/2Cl- cotransporter (NKCC2) and Na+/Cl- cotransporter (NCC) in the CHH group were lower than the CHL group. Expression of epithelial sodium channel (ENaC)-γ increased in the CHH group. In contrast, expressions of NKCC2 and NCC in the NHH group didn't show any significant alterations, compared to the NHL group. Expressions of ENaC-α and ENaC-β in the NHH group were higher than the CHH group. Adaptive alterations of NKCC2 and NCC to changes of salt intake were different in the uNx group, and changes in ENaC-α and ENaC-β were also different. These altered regulations of sodium transporters may be involved in the pathogenesis of SSH in the uNx rat model

    Prealbumin is Not Sensitive Indicator of Nutrition and Prognosis in Critical Ill Patients

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    It was reported that 30-50% of inpatients are in a malnutrition status. Measuring the prealbumin level is a sensitive and cost-effective method for assessing the severity of illness in critically or chronically ill patients. However it is uncertain whether or not the prealbumin level correlates with the level of nutrition support and outcomes in critically ill patients. The aim of this study was to evaluate serum prealbumin level as an indicator of the effectiveness of nutrition support and the prognosis in critically ill patients. Forty-four patients who received total parenteral nutrition for more than 7 days at an intensive care unit (ICU) were studied. The serum prealbumin was measured at the initial time of nutrition support and at the almost seventh day since the first measurement. The patients were allocated into two groups. In Group 1 (n=31) and 2 (n=13), the prealbumin level increased and decreased, respectively. Age, APACHE II score, nutrition status, nutritional requirement and amount of supply, mortality, hospital day and ICU day in the two groups were compared. The serum prealbumin level increased in 31 out of the 44 patients. The average calorie intake was 1334 Kcal/day (83% of energy requirement) in Group 1 and 1170 kcal/day (76% of energy requirement) in Group 2 (p=0.131). The mortality was 42% in Group 1 and 54% in Group 2 (p=0.673). The average hospital day/ ICU day in Groups 1 and 2 were 80 days/38 days and 60 days/31 days respectively. In conclusion, in critically ill patients, the serum prealbumin level did not respond sensitively to nutritional support. In addition an increase in the prealbumin level dose not indicate a better prognosis for critically ill patients

    Influence of the rheological behaviour of the lubricant on the appearance of pitting in elastohydrodynamic eegime

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    This paper analyses the influence of lubricant behaviour on the appearance of pitting. It attempts to study the effect of viscosity?pressure relation, compressibility, film thickness?roughness relation and friction coefficient on pitting failure of the contacting elements.To explain these effects, we first deal with the influence of the oil on the lubrication of the contact using elastohydrodynamic theory and secondly two multiaxial fatigue criteria are used, Crossland criterion and Dang Van criterion, to evaluate the influence of the rheology on the appearance of pitting. Finally, different applications are presented together with a discussion on the results obtained
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