74 research outputs found

    The magnetocaloric effect and critical behavior in amorphous Gd 60Co 40-xMn x alloys.

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    The amorphous alloys Gd60Co40−xMnx (x = 0, 5, 10, 15) were prepared by melt spinning. The Curie temperature,T c, increases monotonously with Mn addition, ranging from 198 K for x = 0 to 205 K for x = 15, while the maximum values of −ΔSM under the applied field change from 0 to 5 T are 7.7, 7.1, 6.2 and 5.4 J·kg−1·K−1 for x = 0, 5, 10, and 15, respectively. All samples undergo a second order ferri-paramagnetic phase transition. The critical behavior around the transitiontemperature is investigated in detail, using both the standard Kouvel-Fisher procedure as well as the study of the field dependence of the magnetocaloric effect. Results indicate that the obtained critical exponents are reliable, and that the present alloys exhibit local magnetic interaction

    Escherichia coli GutM4 produces 2,5-diketopiperazines and inhibits human pathogens in vitro

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    Background: It has been a very common practice to use probiotics or their metabolites as alternative antimicrobial strategies for the treatment and prevention of infections as rampant and indiscriminate use of antibiotics causes the development of antibiotic-resistant pathogens. The objective of this study was to select a potential antimicrobial probiotic strain of Escherichia coli from the human gastrointestinal tract and investigate the production of diketopiperazines that contribute to the antimicrobial activity. Results: E. coli GutM4was isolated from the feces of a healthy adult. E. coli GutM4 showed significant antagonistic activity against 10 indicator pathogens, and this activity was no less than that of the reference strain E. coli Nissle 1917 against eight of the indicator pathogens. Moreover, E. coli GutM4 produced antagonistic substances containing trypsin-targeted peptide bonds because the inhibitory effects of E. coli GutM4 supernatant significantly decreased upon treatment with trypsin. Consistent with the antagonistic activity and peptide compounds of E. coli GutM4, 14 2,5-diketopiperazines were isolated from the fermented broth of E. coli GutM4, including 12 cyclo(Pro-Phe), 3 cyclo(Pro-Tyr), and 5 cyclo(4-hydroxyl-Pro-Leu), which are reported to have antipathogenic activity. Conclusion: E. coli GutM4 produces 2,5-diketopiperazines that are partly involved in antagonistic action against human pathogens in vitro

    Early myocardial dysfunction in streptozotocin-induced diabetic mice: a study using in vivo magnetic resonance imaging (MRI)

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    BACKGROUND: Diabetes is associated with a cardiomyopathy that is independent of coronary artery disease or hypertension. In the present study we used in vivo magnetic resonance imaging (MRI) and echocardiographic techniques to examine and characterize early changes in myocardial function in a mouse model of type 1 diabetes. METHODS: Diabetes was induced in 8-week old C57BL/6 mice with two intraperitoneal injections of streptozotocin. The blood glucose levels were maintained at 19–25 mmol/l using intermittent low dosages of long acting insulin glargine. MRI and echocardiography were performed at 4 weeks of diabetes (age of 12 weeks) in diabetic mice and age-matched controls. RESULTS: After 4 weeks of hyperglycemia one marker of mitochondrial function, NADH oxidase activity, was decreased to 50% of control animals. MRI studies of diabetic mice at 4 weeks demonstrated significant deficits in myocardial morphology and functionality including: a decreased left ventricular (LV) wall thickness, an increased LV end-systolic diameter and volume, a diminished LV ejection fraction and cardiac output, a decreased LV circumferential shortening, and decreased LV peak ejection and filling rates. M-mode echocardiographic and Doppler flow studies of diabetic mice at 4 weeks showed a decreased wall thickening and increased E/A ratio, supporting both systolic and diastolic dysfunction. CONCLUSION: Our study demonstrates that MRI interrogation can identify the onset of diabetic cardiomyopathy in mice with its impaired functional capacity and altered morphology. The MRI technique will lend itself to repetitive study of early changes in cardiac function in small animal models of diabetic cardiomyopathy

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    Observations on biotic parameters of Angora rabbit breed under controlled conditions in different housing systems

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    Aim: The aim of the present study was to compare the body weight (BW) gain and physiological parameters such as temperature, respiratory rate (RR), and heart rate (HR) of Angora rabbit reared in different housing systems. Materials and Methods: A total of 30 angora rabbits (age 4-6 months), weight 1.5 kg in average were divided into three groups, i.e., (outdoor control [OC], indoor in cages [IC], and indoor open [IO]). All rabbits were reared for 10 weeks. Feed and water were given ad libitum. BW gain and physiological parameters such as temperature, RR, and HR were recorded. Results: All parameters showed some degree of variations. The BW differed significantly (p<0.05). The mean BW in kilogram (kg) of OC group was 1.59±0.03 obtained during the experimental period, while the BW of IC group shows a decrease of 1.43±0.05 and IO group it was 1.49±0.06 kg. The body temperature (BT) of the control group was 38.83±1.07°C, but IC and IO groups show increased in BT (39.10±0.78°C) and (39.33±1.24°C), indicated no significant difference among the groups (p=0.05). The RR in breaths/min of OC group recorded was 40.3±5.20, but the RR recorded for IC and IO groups was 41.2±7.29 and 39.3±6.30 breaths/min, respectively, showed less variation. The HR obtained in beat/min of OC group was 136.9±15.22, IC group (139.1±16.42) and IO group were (139.6±19.90 beat/min) showed less substantial variation. Conclusion: The present study clearly indicates that housing rabbits in cages and stress condition is a cause of poor welfare due to movement constraint, it will affect the body biotic parameters such as normal temperature, respiration as well as it can reduce the growth performance of animals significantly but housing system may not affect HR

    Escherichia coli GutM4 produces 2,5-diketopiperazines and inhibits human pathogens in vitro

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    Background: It has been a very common practice to use probiotics or their metabolites as alternative antimicrobial strategies for the treatment and prevention of infections as rampant and indiscriminate use of antibiotics causes the development of antibiotic-resistant pathogens. The objective of this study was to select a potential antimicrobial probiotic strain of Escherichia coli from the human gastrointestinal tract and investigate the production of diketopiperazines that contribute to the antimicrobial activity. Results: E. coli GutM4 was isolated from the feces of a healthy adult. E. coli GutM4 showed significant antagonistic activity against 10 indicator pathogens, and this activity was no less than that of the reference strain E. coli Nissle 1917 against eight of the indicator pathogens. Moreover, E. coli GutM4 produced antagonistic substances containing trypsin-targeted peptide bonds because the inhibitory effects of E. coli GutM4 supernatant significantly decreased upon treatment with trypsin. Consistent with the antagonistic activity and peptide compounds of E. coli GutM4, 14 2,5-diketopiperazines were isolated from the fermented broth of E. coli GutM4, including 12 cyclo(Pro-Phe), 3 cyclo(Pro-Tyr), and 5 cyclo(4-hydroxyl-Pro-Leu), which are reported to have antipathogenic activity. Conclusion: E. coli GutM4 produces 2,5-diketopiperazines that are partly involved in antagonistic action against human pathogens in vitro

    Effects of hydrophilic and hydrophobic SiO2 composite organic resin coating on properties of FeSiCr magnetic powder cores

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    The effects of hydrophilic and hydrophobic SiO2 composite organic resin on the properties of FeSiCr magnetic powder cores and the effects of annealing treatment on magnetic properties were studied. After phosphating, the FeSiCr alloy powders were coated by two types of SiO2 composite resin, which are hydrophobic and hydrophilic, respectively. The FeSiCr magnetic powder cores were prepared by compaction and curing. The results show that the coating effect of coupling modified hydrophilic SiO2 composite organic resin is better than that of hydrophobic SiO2 composite organic resin. With the increase of SiO2 addition, the specific resistance and coercivity of the magnetic powder cores are increased, while the density, saturation magnetization and effective permeability are decreased. The FeSiCr magnetic powder cores coated with 0.5% hydrophobic SiO2 composite organic resin have excellent comprehensive performance after annealing. Under the condition of 20 mT, 100 kHz, the magnetic core loss is 49.84 kW/m3, which is 16.9% lower than that of the magnetic powder cores coated with pure resin. Annealing can effectively promote magnetic properties of FeSiCr magnetic powder cores
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