Free leucine dissociates homo- and heterodimers formed between proteins containing leucine heptad repeats

AbstractA highly specific method for the dissociation of protein dimers has been developed. The method involves exposure of the dimers to free leucine at a concentration ranging between 3 and 10 mM. Using this method it has been possible to dissociate goat uterine oestrogen receptor homodimers, heterodimers formed between the non-activated oestrogen receptor (naER) and the oestrogen receptor activation factor (E-RAF) of the goat uterus, c-jun homodimers derived from bovine bone marrow and also glucocorticoid receptor homodimers isolated from rat liver cytosol. The pattern of dimer dissociation by leucine clearly differentiates two classes of proteins. The first is represented by steroid hormone receptors where dimerization is apparently contributed by both coiled-coil dimerization interfaces and the conserved heptad repeats of leucine. The second is represented by oncoproteins like c-fos and c-jun which dimerize through the exclusive involvement of leucine zippers. The patterns of dissociation of these two groups of proteins from the concerned affinity columns are distinctly different. This indicates a possibility that the elution pattern may be used as a yardstick to determine whether two proteins dimerize through the exclusive involvement of leucine zippers or whether coiled-coil interfaces are also involved in the dimerization process

Application of blend fuels in a diesel engine

AbstractExperimental study has been carried out to analyze engine performance and emissions characteristics for diesel ngine using different blend fuels without any engine modifications. A total of four fuel samples, such as DF (100% iesel fuel), JB5 (5% jatropha biodiesel and 95% DF), JB10 (10% JB and 90% DF) and J5W5 (5% JB, 5% waste ooking oil and 90% DF) respectively were used in this study. Engine performance test was carried out at 100% load eeping throttle 100% wide open with variable speeds of 1500 to 2400rpm at an interval of 100rpm. Whereas, mission tests were carried out at 2300rpm at 100% and 80% throttle position. As results of investigations, the erage torque reduction compared to DF for JB5, JB10 and J5W5 was found as 0.63%, 1.63% and 1.44% and verage power reduction was found as 0.67%, 1.66% and 1.54% respectively. Average increase in bsfc compared to F was observed as 0.54%, 1.0% JB10 and 1.14% for JB5, JB10 and J5W5 respectively. In case of engine exhaust as emissions, compared to DF average reduction in HC for JB5, JB10 and J5W5 at 2300rpm and 100% throttle osition found as 8.96%, 11.25% and 12.50%, whereas, at 2300 and 80% throttle position, reduction was as 16.28%, 0.23% and 31.98% respectively. Average reduction in CO at 2300rpm and 100% throttle position for JB5, JB10 and 5W5 was found as 17.26%, 25.92% and 26.87%, whereas, at 80% throttle position, reduction was observed as 0.70%, 33.24% and 35.57%. Similarly, the reduction in CO2 compared to DF for JB5, JB10 and J5W5 at 2300rpm nd 100% throttle position was as 12.10%, 20.51% and 24.91%, whereas, at 80% throttle position, reductions was bserved as 5.98%, 10.38% and 18.49% respectively. However, some NOx emissions were increased for all blend els compared to DF. In case of noise emission, sound level for all blend fuels was reduced compared to DF. It can e concluded that JB5, JB10 and J5W5 can be used in diesel engines without any engine modifications However, 5B5 produced some better results when compared to JB10

Community-Based Participatory Obesity Prevention Interventions in Rural Communities: A Scoping Review

Child obesity is a worldwide public health concern. In America, children from rural areas have greater odds of obesity in comparison to those from urban areas. Community-engaged research is important for all communities, particularly under-represented communities. This paper reports the results of a scoping review investigating community-engaged research in obesity prevention programs tested with school-aged children in rural America. A literature search of Medline Ovid was conducted to identify interventions reporting the results of obesity prevention interventions that promoted a healthy diet or physical activity (PA) behaviors to school-age children in rural communities of the United States (US). After title and abstract review, potentially relevant citations were further examined by assessing the full text. Each stage of review was conducted by two independent reviewers. Twelve studies met the inclusionary criteria and are included in this review. Most of the studies focused on elementary school participants (n = 7) and improving both diet and PA (n = 9). Out of the twelve studies, only five included the target audience in intervention development or implementation. The most popular type of community engagement was community participation (n = 4). This review revealed that community-engaged research is under-utilized in obesity prevention interventions tested with school-aged children in rural US communities

Seasonal variation of hip fractures in patients with Benign Paroxysmal Positional Vertigo

Introduction: Seasonal variation of benign paroxysmal positional vertigo (BPPV) presentation has been reported, with higher rates of presentation in months associated with times of lower serum vitamin D levels. The purpose of this study was to examine the association between the timing of hip fracture in patients with BPPV. Methods: A retrospective review (2013 to 2019) of adult patients was performed at a tertiary care academic center to identify patients with hip fracture due to ground level fall (ICD-10 code S72) and a previously established diagnosis of vestibular disorder (ICD-10 codes H81-83, A88.1, and R42). Included patients were matched by age and sex to control for patients who had hip fracture without a vestibular diagnosis. Patient charts were reviewed, and demographic and clinical data were extracted related to hip fracture and prior vestibular diagnosis. Groups were subdivided based on whether patients had a hip fracture from January to June versus July to December. Fisher’s exact test was used to evaluate for a difference in seasonal variation between groups. Results: There were 201 patients with vestibular disorders of whom 27 patients carried the diagnosis of BPPV, with a mean age of 80.4 years. The rates of hip fracture among patients with BPPV was higher in the period extending from January to June (63.0%) versus July to December (37.0%), [odds ratio 1.59, 95% CI 0.66-4.00]. The rate of hip fracture was not significantly different between these time periods for the control group (51.7% versus 48.3%) or the vestibular group (53.2% versus 46.8%). Conclusion: These results offer preliminary evidence that, in addition to an increased presentation for BPPV during months associated with decreased serum vitamin D, injuries due to BPPV may be increased as well. The present study is limited by the statistical power afforded by the small number of patients with BPPV and hip fracture that were identified

Comparative Studies of Piston Crown Coating with YSZ and Al2O3·SiO2 on Engine out Responses Using Conventional Diesel and Palm Oil Biodiesel

In this study, the effect of a thermal barrier coating with yttria-stabilized zirconia (YSZ) and aluminum silicate (Al2 O3·SiO2) alongside an NiCrAl bond coat on the engine performance and emission analysis was evaluated by using conventional diesel and pure palm oil biodiesel. These materials were coated on the piston alloy via plasma spray coating. The findings demonstrated that YSZ coating presented better engine performances, in terms of brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC) for both fuels. The piston with YSZ coating materials achieved the highest BTE (15.94% for diesel, 14.55% for biodiesel) and lowest BSFC (498.96 g/kWh for diesel, 619.81 g/kWh for biodiesel). However, Al2 O3·SiO2 coatings indicated better emission with lowest emissions of NO, CO, and CO2 for both diesel and biodiesel. For the uncoated piston, the results indicated that the engine clocked the highest torque and power, especially on diesel fuel due to the high viscosity and low caloric value, and it recorded the lowest hydrocarbon emission due to the complete combustion of fuel in the engine. Hence, it was concluded that the YSZ coating could lead to better engine performance, while Al2 O3·SiO2 showed promising results in terms of greenhouse gas emission

Effect of thermal barrier coating on the performance and emissions of diesel engine operated with conventional diesel and palm oil biodiesel

In this study, the performance and emission of a thermal barrier coating (TBC) engine which applied palm oil biodiesel and diesel as a fuel were evaluated. TBC was prepared by using a series of mixture consisting different blend ratio of yttria stabilized zirconia (Y2O3·ZrO2) and aluminum oxide-silicon oxide (Al2O3·SiO2) via plasma spray coating technique. The experimental results showed that mixture of TBC with 60% Y2O3·ZrO2 + 40% Al2O3·SiO2 had an excellent nitrogen oxide (NO), carbon monoxide (CO), carbon dioxide (CO2), and unburned hydrocarbon (HC) reductions compared to other blend-coated pistons. The finding also indicated that coating mixture 50% Y2O3·ZrO2 + 50% Al2O3·SiO2 had the highest brake thermal efficiency (BTE) and lowest of brake specific fuel consumption (BSFC) compared to all mixture coating. Reductions of HC and CO emissions were also recorded for 60% Y2O3·ZrO2 + 40% Al2O3·SiO2 and 50% Y2O3·ZrO2 + 50% Al2O3·SiO2 coatings. These encouraging findings had further proven the significance of TBC in enhancing the engine performance and emission reductions operated with different types of fuel

Friction and Wear Performance Evaluation of Bio-Lubricants and DLC Coatings on Cam/Tappet Interface of Internal Combustion Engines.

The environmental concerns associated with artificially formulated engine oils have forced a shift towards bio-based lubricants. The deposition of hard coatings on engine components and migrating to environmentally friendly green lubricants can help in this regard. Chemically modified forms of vegetable oils, with better low-temperature characteristics and enhanced thermo-oxidative stability, are suitable substitutes to conventional lubricant base oils. The research presented in this manuscript was undertaken to experimentally investigate the wear and friction performance of a possible future generation of an environmentally friendly bio-based lubricant as a potential replacement for conventional engine lubricants. In order to quantify the tribological benefits which can be gained by the deposition of DLC coatings, (an (a-C:H) hydrogenated DLC coating and an (a-C:H:W) tungsten-doped DLC coating) were applied on the cam/tappet interface of a direct acting valve train assembly of an internal combustion engine. The tribological correlation between DLC-coated engine components, lubricant base oils and lubricant additives have been thoroughly investigated in this study using actual engine operating conditions. Two additive-free base oils (polyalphaolefines (PAO) and chemically-modified palm oil (TMP)) and two multi-additive-containing lubricants were used in this investigation. Real-time drive torque was measured to determine the friction force, detailed post-test analysis was performed, which involved the use of a specialized jig to measure camlobe wear. An optical profilometer was used to measure the wear on the tappet, high-resolution scanning electron microscopy was employed to study the wear mechanism and energy-dispersive X-ray spectroscopy was performed on the tested samples to qualitatively access the degradation of the coating. When using additive-free TMP, a low friction coefficient was observed for the cam/tappet interface. The presence of additives further improved the friction characteristics of TMP, resulting in reduced average friction torque values. A tremendous enhancement in wear performance was recorded with a-C:H-coated parts and the coating was able to withstand the test conditions with little or no delamination

Membrane-Bound sn-1,2-Diacylglycerols Explain the Dissociation of Hepatic Insulin Resistance from Hepatic Steatosis in MTTP Knockout Mice

Microsomal triglyceride transfer protein (MTTP) deficiency results in a syndrome of hypolipidemia and accelerated NAFLD. Animal models of decreased hepatic MTTP activity have revealed an unexplained dissociation between hepatic steatosis and hepatic insulin resistance. Here, we performed comprehensive metabolic phenotyping of liver-specific MTTP knockout (L-Mttp(-/-)) mice and age-weight matched wild-type control mice. Young (10-12-week-old) L-Mttp(-/-) mice exhibited hepatic steatosis and increased DAG content; however, the increase in hepatic DAG content was partitioned to the lipid droplet and was not increased in the plasma membrane. Young L-Mttp(-/-) mice also manifested normal hepatic insulin sensitivity, as assessed by hyperinsulinemic-euglycemic clamps, no PKC epsilon activation, and normal hepatic insulin signaling from the insulin receptor through AKT Ser/Thr kinase. In contrast, aged (10-month-old) L-Mttp(-/-) mice exhibited glucose intolerance and hepatic insulin resistance along with an increase in hepatic plasma membrane sn-1,2-DAG content and PKC epsilon activation. Treatment with a functionally liver-targeted mitochondrial uncoupler protected the aged L-Mttp(-/-) mice against the development of hepatic steatosis, increased plasma membrane sn-1,2-DAG content, PKC epsilon activation, and hepatic insulin resistance. Furthermore, increased hepatic insulin sensitivity in the aged controlled-release mitochondrial protonophore-treated L-Mttp(-/-) mice was not associated with any reductions in hepatic ceramide content. Taken together, these data demonstrate that differences in the intracellular compartmentation of sn-1,2-DAGs in the lipid droplet versus plasma membrane explains the dissociation of NAFLD/lipid-induced hepatic insulin resistance in young L-Mttp(-/-) mice as well as the development of lipid-induced hepatic insulin resistance in aged L-Mttp(-/-) miceThis work was supported by National Institutes of Health Grants R01 DK116774, R01 DK119968, R01 DK114793, R01 DK113984, K23 DK10287, P30 DK045735, DK121490, and HL137202 and the Veterans Health Administration Merit Review Awards I01 BX000901 and BX004113. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the U.S. Department of Veterans Affair

Prevention of Hepatic Steatosis and Hepatic Insulin Resistance by Knockdown of cAMP Response Element-Binding Protein

SummaryIn patients with poorly controlled type 2 diabetes mellitus (T2DM), hepatic insulin resistance and increased gluconeogenesis contribute to fasting and postprandial hyperglycemia. Since cAMP response element-binding protein (CREB) is a key regulator of gluconeogenic gene expression, we hypothesized that decreasing hepatic CREB expression would reduce fasting hyperglycemia in rodent models of T2DM. In order to test this hypothesis, we used a CREB-specific antisense oligonucleotide (ASO) to knock down CREB expression in liver. CREB ASO treatment dramatically reduced fasting plasma glucose concentrations in ZDF rats, ob/ob mice, and an STZ-treated, high-fat-fed rat model of T2DM. Surprisingly, CREB ASO treatment also decreased plasma cholesterol and triglyceride concentrations, as well as hepatic triglyceride content, due to decreases in hepatic lipogenesis. These results suggest that CREB is an attractive therapeutic target for correcting both hepatic insulin resistance and dyslipidemia associated with nonalcoholic fatty liver disease (NAFLD) and T2DM