Methods of Measuring Mitochondrial Potassium Channels: A Critical Assessment

In this paper, the techniques used to study the function of mitochondrial potassium channels are critically reviewed. The majority of these techniques have been known for many years as a result of research on plasma membrane ion channels. Hence, in this review, we focus on the critical evaluation of techniques used in the studies of mitochondrial potassium channels, describing their advantages and limitations. Functional analysis of mitochondrial potassium channels in comparison to that of plasmalemmal channels presents additional experimental challenges. The reliability of functional studies of mitochondrial potassium channels is often affected by the need to isolate mitochondria and by functional properties of mitochondria such as respiration, metabolic activity, swelling capacity, or high electrical potential. Three types of techniques are critically evaluated: electrophysiological techniques, potassium flux measurements, and biochemical techniques related to potassium flux measurements. Finally, new possible approaches to the study of the function of mitochondrial potassium channels are presented. We hope that this review will assist researchers in selecting reliable methods for studying, e.g., the effects of drugs on mitochondrial potassium channel function. Additionally, this review should aid in the critical evaluation of the results reported in various articles on mitochondrial potassium channels.     

凝胶体系中混合羧酸钾对草酸钙结晶的调控作用

酒石酸钾(K₂tart)、柠檬酸钾(K₃cit)和乙二胺四乙酸钾(K₂edta)均可用于防治草酸钙(CaOxa) 结石, 但它们各有其优缺点. 本文采用双扩散法比较研究了这3种羧酸钾以不同比例两两混合时对CaOxa结晶的影响, 结果表明, 混合剂或者能够诱导更多的二水草酸钙(COD)和三水草酸钙(COT)晶体, 或者减小一水草酸钙(COM)的尺寸, K₂edta-K₃cit混合剂还能诱导(100)晶面减小、螺旋式生长的COD晶体, 该COD与肾小管细胞膜的粘附力较弱. 这些均有利于抑制草酸钙结石形成, 表明混合剂的防石效果优于单一钾盐.     

Conversion Reaction Mechanism of Ultrafine Bimetallic Co‐Fe Selenides Embedded in Hollow Mesoporous Carbon Nanospheres and Their Excellent K‐Ion Storage Performance

Potassium‐ion batteries (KIBs) are considered as promising alternatives to lithium‐ion batteries owing to the abundance and affordability of potassium. However, the development of suitable electrode materials that can stably store large‐sized K ions remains a challenge. This study proposes a facile impregnation method for synthesizing ultrafine cobalt–iron bimetallic selenides embedded in hollow mesoporous carbon nanospheres (HMCSs) as superior anodes for KIBs. This involves loading metal precursors into HMCS templates using a repeated “drop and drying” process followed by selenization at various temperatures, facilitating not only the preparation of bimetallic selenide/carbon composites but also controlling their structures. HMCSs serve as structural skeletons, conductive templates, and vehicles to restrain the overgrowth of bimetallic selenide particles during thermal treatment. Various analysis strategies are employed to investigate the charge–discharge mechanism of the new bimetallic selenide anodes. This unique‐structured composite exhibits a high discharge capacity (485 mA h g^?1 at 0.1 A g^?1 after 200 cycles) and enhanced rate capability (272 mA h g^?1 at 2.0 A g^?1) as a promising anode material for KIBs. Furthermore, the electrochemical properties of various nanostructures, from hollow to frog egg‐like structures, obtained by adjusting the selenization temperature, are compared.     

3D Sulfur and Nitrogen Codoped Carbon Nanofiber Aerogels with Optimized Electronic Structure and Enlarged Interlayer Spacing Boost Potassium‐Ion Storage

Carbonaceous materials are promising anodes for potassium‐ion batteries (PIBs). However, it is hard for large K ions (1.38 Å) to achieve long‐distance diffusion in pristine carbonaceous materials. In this work, the following are synthesized: S/N codoped carbon nanofiber aerogels (S/N‐CNFAs) with optimized electronic structure by S/N codoping, enhanced interlayer spacing by S doping, and a 3D interconnected porous structure of aerogel, through a pyrolysis sustainable seaweed (Fe‐alginate) aerogel strategy. Specifically, the S/N‐CNFAs electrode delivers high reversible capacities of 356 and 112 mA h g^?1 at 100 and 5000 mA g^?1, respectively. The capacity reaches 168 mA h g^?1 at 2000 mA g^?1 after 1000 cycles. A full cell with a S/N‐CNFAs anode and potassium prussian blue cathode displays a specific capacity of 198 mA h g^?1 at 200 mA g^?1. Density functional theory calculations indicate that S/N codoping is beneficial to synergistically improve K ions storage of S/N‐CNFAs by enhancing the adsorption of K ions and reducing the diffusion barrier of K ions. This work offers a facile heteroatom doping paradigm for designing new carbonaceous anodes for high‐performance PIBs.     

用反滴定法测定小麦粉中溴酸钾含量

采用反滴定测定小麦粉中溴酸钾的含量.研究了测定条件及干扰因素对测定的影响,并与AACC方法进行了比较.方法操作简单、灵活、实用,最低检出限0.01g/kg,标准偏差(S)小于0.56,相对标准偏差小于1.24%,回收率为:91.6%～95.2%.     

玉米淀粉氧化工艺的研究

研究了玉米淀粉的氧化工艺。通过次氯酸钠、过氧化氢、高锰酸钾二次氧化、高碘酸钠氧化的比较,优选了高锰酸钾二次氧化作正交实验。直观分析及方差分析结果表明,最佳的氧化工艺为:氢氧化钠0.6 g,硫酸3 g,淀粉乳浓度40%,高锰酸钾1.2 g。     

离子交换法制备钛酸钾纳米纤维及其表征

采用离子交换法,以KOH溶液与钛酸纳米管（H2Ti2O4（OH）2）反应,制备了钛酸钾纳米纤维。透射电镜（TEM）和X-射线衍射分析（XRD）结果表明,经过离子交换,形貌由纳米管变为纳米纤维,晶体结构亦发生改变。利用原子吸收分光光度法、比色法和X-射线光电子能谱（XPS）对离子交换产物的Ti、K元素的原子比和化学价态进行分析,结果表明,离子交换产物的经验式为：K1.34H0.66Ti2O4（OH）2。与H2Ti2O4（OH）2纳米管相比,钛酸钾纳米纤维的热稳定性较好,700℃以上的热处理才使其晶型发生改变,出现单斜型的K2Ti4O9。高温处理导致钛酸钾纳米纤维的直径增加,但仍保持较大长径比。该材料的BET比表面为104m2·g^-1。     

四乙酰基二苄基六氮杂异伍兹烷的氧化脱苄研究

采用高锰酸钾作为氧化剂，乙酸酐作为反应介质，在三氟化硼乙醚的催化下对四乙酰基二苄基六氮杂异伍兹烷（TADBIW）进行氧化脱苄，得到四乙酰基二苯甲酰基六氮杂异伍兹烷（1）和未见文献报道的四乙酰基一苯甲酰基一苄基六氮杂异伍兹烷（2），并第一次通过氧化法得到六乙酰基六氮杂异伍兹烷（3）。     

有机盐抑制黏土水化膨胀应用

考察了氯化钾在黏土、石英砂表面的吸附量以及甲酸钾和甲酸铵在蒙脱土表面的吸附量,对比研究了有机盐OS500A(含甲酸钾75%)溶液、OS500B(含甲酸铵75%)溶液、氯化钾溶液和清水抑制黏土水化分散的情况。结果表明:无论是氯化钾溶液还是有机盐甲酸钾或甲酸铵溶液,随着盐溶液浓度增大,盐吸附量逐渐增加。当氯化钾溶液质量浓度为160 g/L时,氯化钾在蒙脱土、高岭土和石英砂表面的最大饱和吸附量分别为5.6、2.06和1.57mg;当甲酸盐溶液质量浓度接近100 g/L时,蒙脱土对甲酸钾、甲酸铵的最大吸附量分别为5.51和5.42mg。蒙脱土对有机盐的吸附较易达到饱和,其饱和最大吸附量与无机盐相当。粒度分析结果表明,抑制黏土水化分散能力的强弱顺序为:甲酸铵(OS500B)>甲酸钾(OS500A)>5%氯化钾>清水。用煤油改变岩石表面的润湿性,有助于提高有机盐抑制黏土水化膨胀的作用。用氯化钾复配甲酸盐体系在阜东地区现场应用10口井,保护效果明显。