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Studies were conducted to assess the utility of free solution capillary electrophoresis (CE) for monitoring the effects of selected excipients on the thermal denaturation of a model protein (Ribonuclease A, RNase A) at low pH. Thermal denaturation/unfolding experiments were conducted via temperature-controlled CE using a run buffer of 20 mM citric acid in the pH range of 2.3-3.1, with a marker peptide incorporated to correct for temperature-induced changes in endoosmotic flow. The effects of selected excipients on the thermal unfolding of RNase A were then evaluated by adding either sorbitol, sucrose, polyethylene glycol 400 (PEG 400) or 2-methyl-2,4-pentanediol (MPD) to the electrophoretic run buffer (pH 2.3). Confirmatory denaturation experiments were conducted under the same solution conditions using circular dichroism (CD) spectropolarimetry. Using temperature-controlled CE, an increase in solution pH from 2.3 to 2.7 and 3.1 resulted in an increase in transition temperatures of RNase A by approximately 8 and 13 degrees C, respectively. Similar shifts in transition temperatures were observed when thermal denaturation transitions were monitored by far-UV CD. Sorbitol (0.55-1.1 M) and sucrose (0.55 M) each shifted the denaturation transition temperatures of RNase A to higher values, whereas PEG 400 and MPD had minimal effect on the unfolding transition midpoint at the concentrations evaluated (0.55 M for each). The observed changes in the transition temperatures for RNase A as a function of pH and selected excipients were similar when measured by either CE or far-UV CD. These results support the utility of CE for monitoring the effects of neutral excipients on the thermal denaturation of a model protein under selected conditions. The widespread utility of the technique may be limited by the narrow temperature range of most commercial CE instruments and the need to use extreme pH conditions to monitor the complete denaturation transition.  相似文献   
3.
A computational framework for scale‐bridging in multi‐scale simulations is presented. The framework enables seamless combination of at‐scale models into highly dynamic hierarchies to build a multi‐scale model. Its centerpiece is formulated as a standalone module capable of fully asynchronous operation. We assess its feasibility and performance for a two‐scale model applied to two challenging test problems from impact physics. We find that the computational cost associated with using the framework may, as expected, become substantial. However, the framework has the ability of effortlessly combining at‐scale models to render complex multi‐scale models. The main source of the computational inefficiency of the framework is related to poor load balancing of the lower‐scale model evaluation We demonstrate that the load balancing can be efficiently addressed by recourse to conventional load‐balancing strategies. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
4.
Abstract

It is a disconcerting pleasure to meet old friends in unexpected settings. Mrs Cameron, whose name will be forever linked with Freshwater and Farringford on the Isle of Wight, spent her youth and early married life in India, returning home only in 1848. So it came about that she happened to be standing on the banks of the River Hooghly at Calcutta in the autumn of 1847, when the steamer carrying a young girl fresh from England let down its anchor. Miss Emily Metcalfe noted with maddening discretion in her journal.  相似文献   
5.
对于是否能找到达标的部件来满足WEEE和RoHS指令的要求,我们早已经被灌输得很多了,以至于我们忽视了一个更加重要的问题。这些指令的最终目的并不是要确保产品达标,或者开发出有效的回收计划,而是要避免使用有害物质,进而也就不需要回收计划了。  相似文献   
6.
Abdominal aortic aneurysm (AAA) is an inflammatory disease associated with marked changes in the cellular composition of the aortic wall. This study aims to identify microRNA (miRNA) expression in aneurysmal inflammatory cells isolated by laser microdissection from human tissue samples. The distribution of inflammatory cells (neutrophils, B and T lymphocytes, mast cells) was evaluated in human AAA biopsies. We observed in half of the samples that adventitial tertiary lymphoid organs (ATLOs) with a thickness from 0.5 to 2 mm were located exclusively in the adventitia. Out of the 850 miRNA that were screened by microarray in isolated ATLOs (n = 2), 164 miRNAs were detected in ATLOs. The three miRNAs (miR-15a-3p, miR-30a-5p and miR-489-3p) with the highest expression levels were chosen and their expression quantified by RT-PCR in isolated ATLOs (n = 4), M1 (n = 2) and M2 macrophages (n = 2) and entire aneurysmal biopsies (n = 3). Except for the miR-30a-5p, a similar modulation was found in ATLOs and the two subtypes of macrophages. The modulated miRNAs were then evaluated in the plasma of AAA patients for their potential as AAA biomarkers. Our data emphasize the potential of miR-15a-3p and miR-30a-5p as biomarkers of AAA but also as triggers of ATLO evolution. Further investigations will be required to evaluate their targets in order to better understand AAA pathophysiology.  相似文献   
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Toward understanding why infant rats ingest high levels of ethanol without initiation procedures, the authors tested effects of mu and kappa receptor antagonists on ethanol reinforcement in neonatal rats. After an intracisternal injection of CTOP (mu antagonist), nor-Binaltorphimine (kappa antagonist), or saline, newborn (3-hr-old) rats were given conditioning pairings of an odor with intraorally infused ethanol or a surrogate nipple with ethanol administered intraperitoneally (to minimize ethanol's gustatory attributes). In each case, these opioid antagonists reduced or eliminated ethanol's reinforcement effect. The same effects occurred with saccharin as the reinforcer in olfactory conditioning. The results imply that activation of mu and kappa receptors, apparently acting jointly, is necessary for reinforcement or that antagonists of this activity impair basic conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Little is known about the outcome of breast reduction in the previously radiated breast. With the increased popularity of breast conservation in the management of breast cancer, it is inevitable that more women with breast cancer who have had a breast radiated will be seeking breast reduction. Although it would be expected that reduction of the radiated breast would be more challenging and would yield less-pleasing results, it has been unclear whether reduction in the radiated breast could be safely performed without interfering with mammography and cancer surveillance. Our experience using different techniques in three patients demonstrates that such reductions can be effectively and safely done if certain principles are followed. Pedicles should be designed to be broader and shorter than usual, and breast flaps should be undermined or elevated either minimally or not at all.  相似文献   
10.
An experimental survey of the Nb-Ge-C ternary phase diagram was used to determine the equilibrium tie-lines between solid phases in this system. In addition to the binary phases, the system contains a newly discovered ternary phase with an approximate composition of Nb3GeC, and an extensive solution phase extending into the ternary system from the binary β-Nb5Ge3 phase.  相似文献   
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