An Online Observer for Minimization of Pulsating Torque in SMPM Motors

A persistent problem of surface mounted permanent magnet (SMPM) motors is the non-uniformity of the developed torque. Either the motor design or the motor control needs to be improved in order to minimize the periodic disturbances. This paper proposes a new control technique for reducing periodic disturbances in permanent magnet (PM) electro-mechanical actuators, by advancing a new observer/estimator paradigm. A recursive estimation algorithm is implemented for online control. The compensating signal is identified and added as feedback to the control signal of the servo motor. Compensation is evaluated for different values of the input signal, to show robustness of the proposed method.     

Mechanisms Regulating Insulin Response to Intragastric Glucose in Lean and Non-Diabetic Obese Subjects: A Randomized,Double-Blind,Parallel-Group Trial

Background/Objectives

The changes in blood glucose concentrations that result from an oral glucose challenge are dependent on the rate of gastric emptying, the rate of glucose absorption and the rate of insulin-driven metabolism that include the incretins, glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). The rate of insulin-driven metabolism is clearly altered in obese subjects, but it is controversial which of these factors is predominant. We aimed to quantify gastric emptying, plasma insulin, C-peptide, glucagon and glucose responses, as well as incretin hormone secretions in obese subjects and healthy controls during increasing glucose loads.

Subjects/Methods

The study was conducted as a randomized, double-blind, parallel-group trial in a hospital research unit. A total of 12 normal weight (6 men and 6 women) and 12 non-diabetic obese (BMI > 30, 6 men and 6 women) participants took part in the study. Subjects received intragastric loads of 10 g, 25 g and 75 g glucose dissolved in 300 ml tap water.

Results

Main outcome measures were plasma GLP-1 and GIP, plasma glucagon, glucose, insulin, C-peptide and gastric emptying. The primary findings are: i) insulin resistance (P < 0.001) and hyperinsulinemia (P < 0.001); ii) decreased insulin disposal (P < 0.001); iii) trend for reduced GLP-1 responses at 75 g glucose; and iv) increased fasting glucagon levels (P < 0.001) in obese subjects.

Conclusions

It seems that, rather than changes in incretin secretion, fasting hyperglucagonemia and consequent hyperglycemia play a role in reduced disposal of insulin, contributing to hyperinsulinemia and insulin resistance.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01875575","term_id":"NCT01875575"}}NCT01875575     

Methanolic Extract of Piper nigrum Fruits Improves Memory Impairment by Decreasing Brain Oxidative Stress in Amyloid Beta(1–42) Rat Model of Alzheimer’s Disease

The present study analyzed the possible memory-enhancing and antioxidant proprieties of the methanolic extract of Piper nigrum L. fruits (50 and 100 mg/kg, orally, for 21 days) in amyloid beta(1–42) rat model of Alzheimer’s disease. The memory-enhancing effects of the plant extract were studied by means of in vivo (Y-maze and radial arm-maze tasks) approaches. Also, the antioxidant activity in the hippocampus was assessed using superoxide dismutase-, catalase-, glutathione peroxidase-specific activities and the total content of reduced glutathione, malondialdehyde, and protein carbonyl levels. The amyloid beta(1–42)-treated rats exhibited the following: decrease of spontaneous alternations percentage within Y-maze task and increase of working memory and reference memory errors within radial arm-maze task. Administration of the plant extract significantly improved memory performance and exhibited antioxidant potential. Our results suggest that the plant extract ameliorates amyloid beta(1–42)-induced spatial memory impairment by attenuation of the oxidative stress in the rat hippocampus.     

Kinetic approach of aflatoxin B1-acetylcholinesterase interaction: a tool for developing surface plasmon resonance biosensors

This work presents a kinetic approach of the interaction between acetylcholinesterase (AChE) from electric eel and aflatoxin B1 (AFB1) or its protein conjugate (e.g., AFB1–HRP [horseradish peroxidase]) in order to develop a simple and sensitive detection method of these compounds. The dissociation constant K_d of the AChE/AFB1–HRP interaction (0.4 μM) obtained with the surface plasmon resonance (SPR) technique is very close to the inhibition constant reported in amperometric assay (K_i = 0.35 μM), proving that the conjugation of AFB1 to a carrier protein does not significantly influence the affinity of AFB1 for AChE. Thus, the AChE/AFB1–HRP couple can be used as mimic system for the binding of AChE to other AFB1–protein adducts and further used for developing biosensors for AFB1 bound to plasma proteins. The immobilization protocol was designed to minimize the nonspecific adsorption on the self-assembled monolayer (SAM) functionalized surface of the SPR chip without an additional hydrophilic linker, whereas the interaction protocol was designed to mark out the possible occurrence of mass transport limitation (MTL) effects. The detection limits (LODs) were 0.008 μM for AFB1–HRP (2.5 ng ml^?1 AFB1) and 0.94 ng ml^?1 for AFB1 itself, which is lower than recently reported values in spectrophotometric and amperometric assays.     

Multiple Functions of BCL-2 Family Proteins

BCL-2 family proteins are the regulators of apoptosis, but also have other functions. This family of interacting partners includes inhibitors and inducers of cell death. Together they regulate and mediate the process by which mitochondria contribute to cell death known as the intrinsic apoptosis pathway. This pathway is required for normal embryonic development and for preventing cancer. However, before apoptosis is induced, BCL-2 proteins have critical roles in normal cell physiology related to neuronal activity, autophagy, calcium handling, mitochondrial dynamics and energetics, and other processes of normal healthy cells. The relative importance of these physiological functions compared to their apoptosis functions in overall organismal physiology is difficult to decipher. Apoptotic and noncanonical functions of these proteins may be intertwined to link cell growth to cell death. Disentanglement of these functions may require delineation of biochemical activities inherent to the characteristic three-dimensional shape shared by distantly related viral and cellular BCL-2 family members.     

Arachidonic acid accumulates in the stromal macrophages during thymus involution in diabetes

Diabetes is a debilitating disease with chronic evolution that affects many tissues and organs over its course. Thymus is an organ that is affected early after the onset of diabetes, gradually involuting until it loses most of its thymocyte populations. We show evidence of accumulating free fatty acids with generation of eicosanoids in the diabetic thymus and we present a possible mechanism for the involution of the organ during the disease. Young rats were injected with streptozotocin and their thymuses examined for cell death by flow cytometry and TUNEL reaction. Accumulation of lipids in the diabetic thymus was investigated by histology and electron microscopy. The identity and quantitation of accumulating lipids was done with gas chromatography-mass spectrometry and liquid chromatography. The expression and dynamics of the enzymes were monitored via immunohistochemistry. Diabetes causes thymus involution by elevating the thymocyte apoptosis. Exposure of thymocytes to elevated concentration of glucose causes apoptosis. After the onset of diabetes, there is a gradual accumulation of free fatty acids in the stromal macrophages including arachidonic acid, the substrate for eicosanoids. The eicosanoids do not cause thymocyte apoptosis but administration of a cyclooxygenase inhibitor reduces the staining for ED1, a macrophage marker whose intensity correlates with phagocytic activity. Diabetes causes thymus involution that is accompanied by accumulation of free fatty acids in the thymic macrophages. Excess glucose is able to induce thymocyte apoptosis but eicosanoids are involved in the chemoattraction of macrophage to remove the dead thymocytes.     

Evaluation of different growth media for the recovery of the species of Alicyclobacillus

AIMS: Five different isolation media, namely potato dextrose agar (PDA), orange serum agar (OSA), K agar, yeast-starch-glucose agar and Bacillus acidocaldarius medium were evaluated for the recovery of Alicyclobacillus spp. from inoculated diluted and undiluted fruit-juice concentrates. METHODS AND RESULTS: Plates of PDA (pH 3.7), spread with vegetative cells (3.9 x 10(6) CFU ml(-1)) of Alicyclobacillus acidoterrestris from single-strength pear juice, recovered 2.9 x 10(6 )CFU ml(-1) after 5 days at 50 degrees C (74% recovery). The recovery of endospores from single-strength pear juice, after a heat treatment at 80 degrees C for 10 min, was higher on spread plates of OSA (pH 5.5) at 50 degrees C for 5 days (97% recovery). CONCLUSIONS: PDA (pH 3.7) and OSA (pH 5.5) at 50 degrees C for 3-5 days recovered the highest numbers of vegative cells and endospores of Alicyclobacillus spp. from sterilized fruit juices and concentrates. SIGNIFICANCE AND IMPACT OF THE STUDY: The most appropriate synthetic media for the recovery of Alicyclobacillus species from inoculated fruit juices and concentrates are shown.     

Emissions of green leaf volatiles and terpenoids from Solanum lycopersicum are quantitatively related to the severity of cold and heat shock treatments

Plant-generated volatiles constitute a sensitive signal of stress response, but quantitative relationships between the stress severity and volatile emissions have been demonstrated only for a few stresses. Among important stresses in the field, chilling and frost stress in spring and heat stress mid-season can significantly curb productivity. We studied the effects of cold and heat shock treatments on leaf photosynthesis and the emission of the volatile products of the lipoxygenase pathway (LOX, also called green leaf volatiles) and mono- and sesquiterpene emissions in tomato (Solanum lycopersicum cv. Mato) to gain quantitative insights into temperature stress-elicited volatile emissions. Both cold and heat stress treatments ranged from mild, which only weakly affected foliage photosynthesis, to severe, which almost completely inhibited photosynthesis. Under non-stressed conditions, LOX emissions were close to the detection limit, and terpene emissions were low. Both cold and heat stress led to enhancement of LOX emissions according to a switch-type response with essentially no emissions under mild stress and major emissions under severe stress. The emissions of mono- and sesquiterpenes increased gradually with the severity of stress, but cold stress resulted in higher sesquiterpene emissions at any given monoterpene emission level. We suggest that the quantitative relationships between the stress strength and emissions observed in this study provide an important means to characterize the severity of cold and heat stresses.