buffer

缓冲区
  • 文章类型: Journal Article
    认可有问题的性暴力相关态度,包括强奸神话接受(RMA),敌对的性别歧视,反对性同意与负面结果有关,包括性暴力的实施。这项研究在770名参与者的样本中检查了社会关系作为与性暴力相关的态度的保护因素。结果表明,在完整的样本中,与工作场所的联系可以保护RMA和敌对的性别歧视,而家庭联系可以保护不赞成性同意,RMA,敌对的性别歧视。其他社会关系的模式在男性和女性的不同模式中有所不同。意外的发现表明与宗教社会群体的联系是一种风险,不是保护性的,因素进行了讨论。
    Endorsing problematic sexual violence-related attitudes including rape myth acceptance (RMA), hostile sexism, and disapproval of sexual consent is associated with negative outcomes, including the perpetration of sexual violence. This study examined social connections as a protective factor for sexual violence-related attitudes among a sample of 770 participants. Results indicate that in the full sample, connections to a workplace were protective for RMA and hostile sexism while family connections were protective for disapproval of sexual consent, RMA, and hostile sexism. Patterns of other social connections differed in separate models for men and women. Unexpected findings indicating that connections to a religious social group are a risk, not a protective, factor are discussed.
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  • 文章类型: Journal Article
    在这项研究中,我们使用了一个自中和系统来抵消酸碱度,不适合木材粘合剂,并在添加柠檬酸或其他有机酸而增强的MUF树脂上进行测试,基于添加小百分比的六胺或另一种合适的有机碱以形成酸-碱缓冲液。以这种方式,粘合剂的pH值保持在最小允许值4以上,并且由于柠檬酸赋予的额外交联,用这种粘合剂体系粘合的木材刨花板和胶合板的强度结果增加。因此,木材/粘合剂界面处的木材成分不会因过低的pH而损坏/降解,从而避免粘接接头的长期使用失效。缓冲系统的添加增加了胶合板和刨花板中粘合线的强度,无论是干燥时还是经过热水和沸水测试。然后,刨花板的IB强度在干燥时增加15-17%,但在沸腾后增加82%。对于胶合板,干燥时和在63℃热水中3小时后的剪切强度为,分别,比对照高37%和90%。粘合面板强度的提高归因于多个原因:(i)速度越慢,由于缓冲液的作用,更规则的交联速率;(ii)由较高的pH值和有机缓冲液的长期稳定性引起的缩聚-降解平衡向左移动;(iii)柠檬酸对某些MUF树脂胺基的额外交联;(iv)已知的柠檬酸与碳水化合物和木质素成分在木材基材界面处的直接连接;(v)柠檬酸可能通过共价连接到木材的某些MUF的羧基
    In this study, we used a self-neutralizing system to counteract too acidic a pH, unsuitable for wood adhesives, and tested it on MUF resins augmented by the addition of citric acid or other organic acids, based on the addition of small percentages of hexamine or another suitable organic base to form an acid-base buffer. In this manner, the pH of the adhesive was maintained above the minimum allowed value of 4, and the strength results of wood particleboard and plywood bonded with this adhesive system increased due to the additional cross-linking imparted by the citric acid. Thus, the wood constituents at the wood/adhesive interface were not damaged/degraded by too low a pH, thus avoiding longer-term service failure of the bonded joints. The addition of the buffering system increased the strength of the bondline in both the plywood and particleboard, both when dry and after hot water and boiling water tests. The IB strength of the particleboard was then increased by 15-17% when dry but by 82% after boiling. For the plywood, the shear strengths when dry and after 3 h in hot water at 63 °C were, respectively, 37% and 90% higher than for the control. The improvement in the bonded panel strength is ascribed to multiple reasons: (i) the slower, more regular cross-linking rate due to the action of the buffer; (ii) the shift in the polycondensation-degradation equilibrium to the left induced by the higher pH and the long-term stability of the organic buffer; (iii) the additional cross-linking by citric acid of some of the MUF resin amine groups; (iv) the already known direct linking of citric acid with the carbohydrates and lignin constituents at the interface of the wood substrate; and (v) the likely covalent linking to the interfacial wood constituents of the prelinked MUF-citric acid resin by some of the unreacted citric acid carboxyl groups.
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  • 文章类型: Journal Article
    背景:目前,马实践中粪便微生物群移植(FMT)缺乏标准化,导致技术高度可变,并且没有关于所施用产品的细菌代谢活性或活力的数据。这项研究的目的是比较马FMT中总的和潜在的代谢活性细菌种群,并评估不同冷冻储存时间的效果,缓冲区,以及马FMT产品的温度。对从三匹健康成年马收集的新鲜粪便进行不同的储存方法。这包括不同的保存溶液(盐水加甘油或仅盐水),温度(-20°C或-80°C),和时间(新鲜,30、60或90天)。样品进行DNA提取以评估总细菌种群(活的和死的组合)和RNA提取,然后逆转录为cDNA作为评估活细菌的替代。然后使用V1-V2区域进行16srRNA基因扩增子测序。
    结果:在评估基于DNA(总)和基于cDNA(潜在代谢活性)的提取方法的结果时,可以看到在属水平上的种群指数和分类组成的最大差异。在社区层面,阿尔法多样性(观察到的物种,Shannon多样性)在基于DNA的分析的冷冻样品中显着降低(P<0.05),对于基于cDNA的测序,差异较小。使用基于DNA的分析,储存时间对细菌群落谱有显著影响(P<0.05)。对于潜在代谢活跃的人群,储存总体上对细菌群落组成的影响较小,具有显著的缓冲作用(P<0.05)。个体马在DNA和cDNA细菌群落中的作用最显著。
    结论:马FMT材料的冷冻储存可以保留马粪便微生物组的潜在代谢活性细菌,用盐水加甘油保存比单独用盐水保存更有效。需要更大规模的研究来确定这些发现是否适用于其他个体马。冷冻用于马患者的FMT材料的能力可以允许在肠道微生物组紊乱的马中更容易地临床使用粪便移植。
    BACKGROUND: Currently, lack of standardization for fecal microbiota transplantation (FMT) in equine practice has resulted in highly variable techniques, and there is no data on the bacterial metabolic activity or viability of the administered product. The objectives of this study were to compare the total and potentially metabolically active bacterial populations in equine FMT, and assess the effect of different frozen storage times, buffers, and temperatures on an equine FMT product. Fresh feces collected from three healthy adult horses was subjected to different storage methods. This included different preservation solutions (saline plus glycerol or saline only), temperature (-20 °C or -80 °C), and time (fresh, 30, 60, or 90 days). Samples underwent DNA extraction to assess total bacterial populations (both live and dead combined) and RNA extraction followed by reverse transcription to cDNA as a proxy to assess viable bacteria, then 16s rRNA gene amplicon sequencing using the V1-V2 region.
    RESULTS: The largest difference in population indices and taxonomic composition at the genus level was seen when evaluating the results of DNA-based (total) and cDNA-based (potentially metabolically active) extraction method. At the community level, alpha diversity (observed species, Shannon diversity) was significantly decreased in frozen samples for DNA-based analysis (P < 0.05), with less difference seen for cDNA-based sequencing. Using DNA-based analysis, length of storage had a significant impact (P < 0.05) on the bacterial community profiles. For potentially metabolically active populations, storage overall had less of an effect on the bacterial community composition, with a significant effect of buffer (P < 0.05). Individual horse had the most significant effect within both DNA and cDNA bacterial communities.
    CONCLUSIONS: Frozen storage of equine FMT material can preserve potentially metabolically active bacteria of the equine fecal microbiome, with saline plus glycerol preservation more effective than saline alone. Larger studies are needed to determine if these findings apply to other individual horses. The ability to freeze FMT material for use in equine patients could allow for easier clinical use of fecal transplant in horses with disturbances in their intestinal microbiome.
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  • 文章类型: Journal Article
    背景:金黄色葡萄球菌是一种常见的病原体,其菌株对现有抗生素具有抗性。来自金黄色葡萄球菌的MurJ(SaMurJ),一种作为脂质II翻转酶的完整膜蛋白,是开发针对这种病原体的新型抗菌剂的潜在目标。该蛋白质的成功表达和纯化将有助于开发针对该靶标的药物。
    目的:在本研究中,我们展示了SaMurJ的优化表达和纯化程序,确定了用于提取和溶解蛋白质的合适洗涤剂,并检查了peptidisc系统以产生无洗涤剂的环境。
    方法:与N-末端10-His标签融合的SaMurJ无诱导表达。选择六种去污剂来筛选用于蛋白质提取和溶解的最有效候选物。通过评估的温度孵育来评估洗涤剂溶解的蛋白质的热稳定性。将不同比例的肽盘双螺旋肽(NSPr)与SaMurJ混合,并应用珠上肽盘组装方法。
    结果:SaMurJ在BL21(DE3)中的表达通过肽指纹图谱得到证实,每升培养物的产量为1毫克SaMurJ。DDM被确定为用于溶解的最佳去污剂,并且镍亲和柱使得SaMurJ纯化具有〜88%的纯度。然而,NSPr不能稳定SaMurJ。
    结论:SaMurJ的表达和纯化是成功的,纯度高,收率好。SaMurJ可以通过含DDM的缓冲液溶解和稳定。
    BACKGROUND: Staphylococcus aureus is a common pathogen with strains that are resistant to existing antibiotics. MurJ from S. aureus (SaMurJ), an integral membrane protein functioning as Lipid II flippase, is a potential target for developing new antibacterial agents against this pathogen. Successful expression and purification of this protein shall be useful in the development of drugs against this target.
    OBJECTIVE: In this study, we demonstrated the optimized expression and purification procedures of SaMurJ, identified suitable detergent for extracting and solubilizing the protein, and examined the peptidisc system to generate a detergent-free environment.
    METHODS: SaMurJ fused with N-terminal ten-His tag was expressed without induction. Six detergents were selected for screening the most efficient candidate for extraction and solubilization of the protein. The thermostability of the detergent-solubilized protein was assessed by evaluated temperature incubation. Different ratios of peptidisc bi-helical peptide (NSPr) to SaMurJ were mixed and the on-bead peptidisc assembly method was applied.
    RESULTS: SaMurJ expressed in BL21(DE3) was confirmed by peptide fingerprinting, with a yield of 1 mg SaMurJ per liter culture. DDM was identified as the optimum detergent for solubilization and the nickel affinity column enabled SaMurJ purification with a purity of ~88%. However, NSPr could not stabilize SaMurJ.
    CONCLUSIONS: The expression and purification of SaMurJ were successful, with high purity and good yield. SaMurJ can be solubilized and stabilized by a DDM-containing buffer.
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  • 文章类型: Journal Article
    在这项研究中,我们系统地探讨了C/Si比的影响,预碳化时间,H2刻蚀时间,6英寸4H-SiC晶片的缓冲层和后续外延层的生长压力。我们的发现表明,缓冲层的C/Si比和生长压力显着影响外延晶片的整体质量。具体来说,0.5的最佳C/Si比和70托的生长压力产生更高质量的外延层。此外,预碳化时间和H2刻蚀时间主要影响外延片的均匀性和表面质量,预碳化时间为3s,H2蚀刻时间为3min,可以提高外延层的表面质量。
    In this study, we systematically explore the impact of C/Si ratio, pre-carbonization time, H2 etching time, and growth pressure on the buffer layer and subsequent epitaxial layer of 6-inch 4H-SiC wafers. Our findings indicate that the buffer layer\'s C/Si ratio and growth pressure significantly influence the overall quality of the epitaxial wafer. Specifically, an optimal C/Si ratio of 0.5 and a growth pressure of 70 Torr yield higher-quality epitaxial layers. Additionally, the pre-carbonization time and H2 etching time primarily affect the uniformity and surface quality of the epitaxial wafer, with a pre-carbonization time of 3 s and an H2 etching time of 3 min found to enhance the surface quality of the epitaxial layer.
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  • 文章类型: Journal Article
    在椎间盘(IVD)退变期间,微环境挑战,如降低葡萄糖水平,氧气,pH在细胞存活和基质周转中起着至关重要的作用。抗酸剂,包埋在微胶囊中的例如Mg(OH)2和CaCO3能够以受控的方式中和酸性微环境,因此可以提供改善退化IVD的酸性生态位和增强基于细胞的再生策略的潜力。这项工作的目标是,首先,开发和表征抗酸剂微胶囊,并评估它们在酸性微环境中的中和能力,第二,在混合凝胶系统中将抗酸剂微胶囊与细胞微胶囊结合,以研究它们在椎间盘外植体模型中作为潜在治疗剂的中和作用。为了实现这一点,我们筛选了五种不同的pH中和剂(Al(OH)3,Mg(OH)2,CaCO3和HEPES),其中Mg(OH)2或CaCO3进行进一步研究。使用电流体动力喷雾工艺形成不同浓度的抗酸-藻酸盐微胶囊,并根据尺寸进行评估,缓冲动力学,细胞相容性,和细胞毒性。最后,在生理变性条件下,在牛椎间盘外植体模型中检查了细胞微胶囊和抗酸胶囊的组合。总的来说,发现CaCO3在中和能力方面是优越的,释放动力学,和细胞反应。具体来说,CaCO3将酸性pH升高至中性水平,并且基于Ca2+释放估计维持数周。使用圆盘外植体模型,已证明CaCO3微胶囊能够增加混合细胞凝胶系统核心内的局部pH。这项工作强调了抗酸剂微胶囊积极改变退行性椎间盘疾病中通常观察到的具有挑战性的酸性微环境条件的潜力。它可以与细胞疗法结合使用以增强再生。
    During intervertebral disc (IVD) degeneration, microenvironmental challenges such as decreasing levels of glucose, oxygen, and pH play crucial roles in cell survival and matrix turnover. Antacids, such as Mg(OH)2 and CaCO3, entrapped in microcapsules are capable of neutralizing acidic microenvironments in a controlled fashion and therefore may offer the potential to improve the acidic niche of the degenerated IVD and enhance cell-based regeneration strategies. The objectives of this work were, first, to develop and characterize antacid microcapsules and assess their neutralization capacity in an acidic microenvironment and, second, to combine antacid microcapsules with cellular microcapsules in a hybrid gel system to investigate their neutralization effect as a potential therapeutic in a disc explant model. To achieve this, we screened five different pH- neutralizing agents (Al(OH)3, Mg(OH)2, CaCO3, and HEPES) in terms of their pH neutralization capacities, with Mg(OH)2 or CaCO3 being carried forward for further investigation. Antacid-alginate microcapsules were formed at different concentrations using the electrohydrodynamic spraying process and assessed in terms of size, buffering kinetics, cell compatibility, and cytotoxicity. Finally, the combination of cellular microcapsules and antacid capsules was examined in a bovine disc explant model under physiological degenerative conditions. Overall, CaCO3 was found to be superior in terms of neutralization capacities, release kinetics, and cellular response. Specifically, CaCO3 elevated the acidic pH to neutral levels and is estimated to be maintained for several weeks based on Ca2+ release. Using a disc explant model, it was demonstrated that CaCO3 microcapsules were capable of increasing the local pH within the core of a hybrid cellular gel system. This work highlights the potential of antacid microcapsules to positively alter the challenging acidic microenvironment conditions typically observed in degenerative disc disease, which may be used in conjunction with cell therapies to augment regeneration.
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  • 文章类型: Journal Article
    钙(Ca2+)之间的串扰,IP3和缓冲液动力学调节肝细胞中的各种机制。独立钙系统的研究,IP3和缓冲信号提供关于细胞动力学的有限信息。在目前的研究中,耦合反应扩散方程用于设计IP3,缓冲区,和肝细胞中的钙动力学。钙的单向反馈,缓冲区,和IP3在ATP生产中,ATP降解,和NADH生产率被纳入模型。已使用沿空间方向的有限元方法(FEM)和沿时间方向的Crank-Nicolson(C-N)方法进行了数值模拟。对数值结果进行分析,以确定IP3,缓冲液,在正常和肥胖条件下,钙对肝细胞中ATP和NADH的产生以及ATP的降解速率的影响。这些发现的比较分析揭示了肥胖在钙动力学方面的显着区别,ATP和NADH合成,和ATP降解动力学。
    The cross talk between calcium (Ca2+), IP3 and buffer dynamics regulate various mechanisms in hepatocyte cells. The study of independent systems of calcium, IP3, and buffer signaling provides limited information about cell dynamics. In the current study, coupled reaction-diffusion equations are used to design a cross-talk model for IP3, buffer, and calcium dynamics in a hepatocyte cell. The one-way feedback of calcium, buffer, and IP3 in ATP production, ATP degradation, and NADH production rate is incorporated into the model. Numerical simulation has been done using the Finite Element Method (FEM) along the spatial direction and the Crank-Nicolson (C-N) method along the temporal direction. The numerical results are analysed to determine the effects of alterations in processes of cross-talking dynamics of IP3, buffer, and calcium on ATP and NADH production and degradation rate of ATP in a hepatocyte cell under normal and obesity conditions. The comparative analysis of these findings unveils notable distinctions induced by obesity in calcium dynamics, ATP and NADH synthesis, and ATP degradation kinetics.
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  • 文章类型: Journal Article
    蛋白质制剂的有效超滤/渗滤方法的设计需要使用具有非常高的蛋白质保留的膜。这项研究的目的是检查特定缓冲液对超滤过程中模型蛋白(牛血清白蛋白)保留的影响。与乙酸盐相比,磷酸盐缓冲液在pH4.8时的白蛋白保留显着降低,柠檬酸盐和组氨酸。这种行为与通过动态光散射确定的有效白蛋白流体动力学直径的小变化一致。使用圆二色光谱和差示扫描量热法探索导致直径变化的潜在构象变化。这些结果为超滤和渗滤过程中控制蛋白质保留的因素提供了重要的见解。
    The design of effective ultrafiltration/diafiltration processes for protein formulation requires the use of membranes with very high protein retention. The objective of this study was to examine the effects of specific buffers on the retention of a model protein (bovine serum albumin) during ultrafiltration. Albumin retention at pH 4.8 was significantly reduced in phosphate buffer compared with that in acetate, citrate, and histidine. This behavior was consistent with a small change in the effective albumin hydrodynamic diameter as determined by dynamic light scattering. The underlying conformational changes leading to this change in diameter were explored using circular dichroism spectroscopy and differential scanning calorimetry. These results provide important insights into the factors controlling protein retention during ultrafiltration and diafiltration.
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  • 文章类型: Journal Article
    目标:了解和操纵油/水界面在各个行业都很重要,包括食物,制药,化妆品,和洗涤剂。这些过程中的许多过程发生在缓冲系统中的升高的pH条件下,其中甘油三酯酯键的碱催化水解导致两亲性反应产物如脂肪酸。
    方法:这里,在存在磷酸盐(PB)和三(羟甲基)氨基甲烷(TRIS)的情况下,分析了pH触发的三油精/水界面变化。液/液界面的椭圆测量法,张力计,和扫描小角度X射线散射用于研究油/水界面处结构的形成。共聚焦拉曼显微镜,核磁共振波谱,和计算机建模分析界面区域的成分变化。
    结果:发现pH和缓冲离子显着修饰了甘油三酸酯/水界面,与癸烷/水控制相反。当pH从6.5增加到9.5时,可以看到界面张力从32.4降低到2.2mN/m,在TRIS存在下,在pH约9.0时形成多层界面层。来自三油苷水解的油酸及其与TRIS的进一步相互作用对此负责。新的理解可以指导pH和离子响应功能材料的设计,并优化涉及甘油三酯/水界面的工业过程。
    OBJECTIVE: Understanding and manipulating the oil/water interface is important across various industries, including food, pharmaceuticals, cosmetics, and detergents. Many of these processes occur under elevated pH conditions in buffer systems, where base-catalyzed hydrolysis of triglyceride ester bonds leads to amphiphilic reaction products such as fatty acids.
    METHODS: Here, pH-triggered alterations of the triolein/water interface are analyzed in the presence of phosphate (PB) and tris(hydroxymethyl)aminomethane (TRIS). Ellipsometry at the liquid/liquid interface, tensiometry, and scanning small angle X-ray scattering are used to study the formation of structures at the oil/water interface. Confocal Raman microscopy, nuclear magnetic resonance spectroscopy, and in silico modeling analyze compositional changes in the interfacial region.
    RESULTS: pH and buffer ions were discovered to significantly modify the triglyceride/water interface, contrary to the decane/water control. Decreasing interfacial tensions from 32.4 to 2.2 mN/m upon pH increase from 6.5 to 9.5 is seen with multilamellar interfacial layers forming at pH around 9.0 in the presence of TRIS. Oleic acid from triolein hydrolysis and its further interaction with TRIS is held responsible for this. The new understanding can guide the design of pH- and ion-responsive functional materials and optimize industrial processes involving triglyceride/water interfaces.
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  • 文章类型: Journal Article
    在温带湖泊,富营养化和温暖的温度会促进蓝藻水华,从而降低水质并损害食物链支持。尽管浮游植物的寄生水可能与浮游动物竞争,它们还通过“mycoloop”间接支持浮游动物种群,这有助于将能量和必需的饮食分子从不可食用的浮游植物转移到浮游动物。这里,我们考虑mycoloop如何适应生物多样性-生态系统功能(BEF)框架。BEF考虑了更多样化的社区如何使浮游动物生产等生态系统功能受益。Chytrids本身是中上层食物网的一部分,它们通过孢子的产生和增加寄主的可食性直接促进浮游动物的饮食。Chytrids可能支持BEF的另一种方式是,如果他们参与“杀死获胜者”动态。与食草动物相比,这导致了“吃就吃”的动态,对于特定于宿主的传染病,可能会发生杀死赢家的动力学,这些传染病控制着优势(在这种情况下是不可食用的)宿主的丰度,从而限制了对较差(在这种情况下是可食用的)竞争者的竞争排斥。因此,如果浮游植物多样性提供功能,Chytrids支持藻类多样性,食糜可以间接地有利于食用浮游植物。所有这三种机制都与多样性有关,因此为浮游动物的生产提供了一些“保险”,以应对富营养化和变暖的影响。在我们的透视作品中,我们探索Chytrid保险假说的证据,确定例外和知识差距,并概述了未来的研究方向。
    In temperate lakes, eutrophication and warm temperatures can promote cyanobacteria blooms that reduce water quality and impair food-chain support. Although parasitic chytrids of phytoplankton might compete with zooplankton, they also indirectly support zooplankton populations through the \"mycoloop\", which helps move energy and essential dietary molecules from inedible phytoplankton to zooplankton. Here, we consider how the mycoloop might fit into the biodiversity-ecosystem functioning (BEF) framework. BEF considers how more diverse communities can benefit ecosystem functions like zooplankton production. Chytrids are themselves part of pelagic food webs and they directly contribute to zooplankton diets through spore production and by increasing host edibility. The additional way that chytrids might support BEF is if they engage in \"kill-the-winner\" dynamics. In contrast to grazers, which result in \"eat-the-edible\" dynamics, kill-the-winner dynamics can occur for host-specific infectious diseases that control the abundance of dominant (in this case inedible) hosts and thus limit the competitive exclusion of poorer (in this case edible) competitors. Thus, if phytoplankton diversity provides functions, and chytrids support algal diversity, chytrids could indirectly favour edible phytoplankton. All three mechanisms are linked to diversity and therefore provide some \"insurance\" for zooplankton production against the impacts of eutrophication and warming. In our perspective piece, we explore evidence for the chytrid insurance hypothesis, identify exceptions and knowledge gaps, and outline future research directions.
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