Location of valinomycin in lipid vesicles

The location of the cyclododecadepsipeptide, valinomycin in vesicles formed from two synthetic lipids is studied by differential scanning calorimetry, spin-label partitioning electron paramagnetic resonance and [1H]-nuclear magnetic resonance. The results show that valinomycin is located near the head group region of dipalmitoyl phosphatidyl choline vesicles and in the hydrophobic core of the dimyristoyl phosphatidyl choline vesicles in the liquid crystalline phase

High resolution nuclear magnetic resonance studies of hen's egg yolk plasma lipoproteins

High resolution nuclear magnetic resonance spectra of native or protease-treated hen's egg yolk plasma (very low density lipoproteins) were taken either in water or deuterated water; the protease-treated samples showed a sharpening of choline methyl proton signal of phospholipid, indicating the hindrance of the choline head-group rotation by the phospholipids in the native very low density lipoproteins. With both native and the protease-treated egg yolk plasma, elevated temperatue increased the signal intensity and produced line-sharpening of Q choline methyl protons and the - CH2-C=O-protons of the methylene group adjacent to the carboxyl group of esterified fatty acids, indicating prior restriction of mobility of these groups. Total extracted lipids of egg yolk plasma containing traces of chloroform, methanol and water (which keep the sample in one phase) also gave similar temperature dependence. Addition of water to the same sample and sonication resulted in the loss of temperature dependence. Frozen and thawed protease-treated egg yolk plasma also behaved in a similar manner. The absence of temperature dependence in these latter two samples is believed to be due to formation of bilayers of phospholipids following phase separation of triglycerides and phospholipids. The results support a model in which the lipoprotein particles of the egg yolk plasma have a lipid-core structure containing triglycerides in the centre with a monomolecular layer of lecithin at the surface, the polar heads of which are surrounded by proteins

A23187-Channel behaviour: fluorescence study

Pyranine entrapped soylipid liposomes have been used as a model system to study the proton transport across membrane in the presence of A23187, a carboxylic ionophore specific for electroneutral exchange of divalent cations. An apparent rate constant (kapp) for transport of protons has been determined from the rate of change of fluorescence intensity of pyranine by stopped flow rapid kinetics in the presence of proton gradient The variation of kapp has been studied as a function of ionophore concentration and the results have been compared with gramicidin-a well known channel former under the similar experimental conditions. The rates thus obtained showed that A23187 is not only a simple carrier but also shows channel behaviour at high concentration of ionophore

Mixed-Criticality Scheduling to Minimize Makespan

In the mixed-criticality job model, each job is characterized by two execution time parameters, representing a smaller (less conservative) estimate and a larger (more conservative) estimate on its actual, unknown, execution time. Each job is further classified as being either less critical or more critical. The desired execution semantics are that all jobs should execute correctly provided all jobs complete upon being allowed to execute for up to the smaller of their execution time estimates, whereas if some jobs need to execute beyond their smaller execution time estimates (but not beyond their larger execution time estimates), then only the jobs classified as being more critical are required to execute correctly. The scheduling of collections of such mixed-criticality jobs upon identical multiprocessor platforms in order to minimize the makespan is considered here

Mechanisms of transmembrane cation transport studied by nuclear magnetic resonance spectroscopy

Several molecules like ionophores, vitamins, ion-binding cyclic peptides, acidic phospholipids, surfactants are known to expose the inner side of vesicles, to the externally added cations. Whereas ionophores and certain other systems bring about these changes by a selective transport (influx) of the cation by specialized mechanisms known as the carrier and channel mechanism, other systems cause lysis and vesicle fusion. These systems have been successfully studied using1H,31 P and13C nuclear magnetic resonance spectroscopy after the demonstration, fifteen years ago, of the ability of paramagnetic lanthanide ions to distinguish the inside of the vesicle from the outside. The results of these'nuclear magnetic resonance kinetics' experiments are reviewed

Reasoning with comparative moral judgements: an argument for Moral Bayesianism

The paper discusses the notion of reasoning with comparative moral judgements (i.e judgements of the form “act a is morally superior to act b”) from the point of view of several meta-ethical positions. Using a simple formal result, it is argued that only a version of moral cognitivism that is committed to the claim that moral beliefs come in degrees can give a normatively plausible account of such reasoning. Some implications of accepting such a version of moral cognitivism are discussed

A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

This is an Accepted Manuscript of an article published by Taylor & Francis in Science and Technology for Build Environment on 06-January 2022, available at: https://doi.org/10.1080/23744731.2021.2017236Natural Science and Engineering Research Council (NSERC), Tempeff North America Inc., Winnipeg, Canada (Project No: 533225-18), ASHRAE.Peer ReviewedDesiccant-coated fixed-bed regenerators (FBRs) can achieve high effectiveness due to high ratio of energy transfer area to volume, and therefore, they are favourable air-to-air energy recovery exchangers for HVAC systems. However, unlike other types of energy recovery exchangers, the air properties (i.e., temperature and humidity) at the outlet of FBRs vary with time. The variations in outlet airflow properties can cause errors in measurements because the measurements include the FBR and sensors transient responses. In this paper, a numerical model is developed to evaluate the performance of desiccant-coated FBRs and their transient operation. The model consists of an exchanger model (FBR model) and sensor (temperature and humidity) models to distinguish the actual performance of the FBR alone from the measured performance, which includes both the FBR and the sensor's response. The model is validated with experimental measurements and available results in the literature. The model can decouple the measured response of the FBR and sensors to predict the FBR performance. This paper's main contribution is an insight into the complex heat and mass transfer processes in desiccant-coated FBRs and measurement sensors. The results of this paper could be used to provide practical recommendations for humidity measurements of different types of desiccant-coated FBRs developed for HVAC applications. Furthermore, the measurement requirements in the current testing standards (ASHRAE 84 and CSA C439-18 standards) for FBRs are examined. Recommendations from this paper could be implemented in future versions of these standards

Theoretical calculations that determine the stability of the knife holder milling tool on a support sliding in the process of operation

In this regard at department of woodworking machines and tools the mill which has an opportunity to change the angles of cutting and an axial corner at the same time is designed and made. It will allow to reduce power by cutting, to increase quality of the processed sur-face and to increase the period of firmness of the tool.На кафедре деревообрабатывающих станков и инструментов спроектирована и изготовлена фреза, у которой есть возможность изменять углы резания и осевой угол одновременно. Это позволит уменьшить мощность на резание, повысить качество обработанной поверхности и увеличить период стойкости инструмента

A high-throughput regeneration protocol for recalcitrant tropical Indian maize (Zea mays L) inbreds

Immature embryos from five select recalcitrant maize (Zea mays L) inbreds used as explants were evaluated for their ability to form callus, somatic embryos and subsequent regeneration into plants. The embryos were placed on N6 basal media with varying levels of 2,4-D (0.5, 1.0, 1.5, 2.0, and 2.5 mg l-1) and were regenerated on MS me¬dium supplemented with BAP (2 - 10 mg l-1), 2,4-D (0.25 mg l-1) and silver nitrate (0.85 mg l-1). Explants cultured on N6 medium supplemented with 2,4-D (2.0 mg l-1) were associated with the highest frequency of embryogenic calli and that of UMI 29 were highly embryogenic (78.67%). When synergism between dicamba and 2,4-D on Type II callus production in UMI 29 was sought to be investigated using 2,4-D (1 or 2 mg l-1) individually and in combina¬tion with dicamba (3.7 mg l-1) production of Type II callus with the greatest frequency of 83.33% was observed on N6 medium containing 3.7 mg l-1 dicamba + 1 mg l-1 2,4-D. The greatest percentage of shoot induction (82.67%) was observed on MS medium supplemented with BAP (10 mg l-1). Among the five genotypes tested, UMI 29 was associated with the highest percentage of callus initiation, shoot induction and mean number of developed shoots. The protocol described in this study can reliably be used to transform tropical maize inbreds as a routine