Spinning of hydroalcoholic chitosan solutions

We investigated the spinning of hydroalcoholic chitosan solutions. The dope composition was optimized in order to obtain a continuous alcogel fiber by water evaporation on heating the extruded hydroalcoholic solution. This alcogel fiber was then neutralized in aqueous alkali baths and washed in water to eliminate the residual alcohol and salts before final drying. Depending on the alcohol content in the filament at the neutralization step, on specific alcohol–chitosan interactions and on the nature and concentration of the coagulation base, the process yielded semicrystalline chitosan fibers with different proportions of anhydrous and hydrated allomorphs. Contrarily to the classical annealing method, the formation of mainly anhydrous crystals was obtained without significant molecular weight decrease by neutralizing the polymer in hydrophobic conditions. The control of allomorph content was shown to be related to the hydrophobicity of the solvent (alcohol fraction) at the neutralization step.     

Speciation of phytate ion in aqueous solution. Non covalent interactions with biogenic polyamines

Abstract

The noncovalent interactions of phytate (Phy^6-) with biogenic amines were studied potentiometrically in aqueous solution, at t= 25°C. Several species are formed in the different H+-Phy^6--amine (A) systems, which have the general formula A_p(Phy)H_q^(12-q)-, with p ≤ 3 and 6 ≤ q ≤ 10. The stability of these species is strictly dependent on the charges involved in the formation equilibria. For the equilibrium pH_iAⁱ⁺ + H_j(Phy)⁽¹²-^j)- = A_p(Phy)H_q(^12q)-, (q = pi + j)we found the relationship logK= aζ (ζ is the charge product of reactants), where a= 0.35(0.03, valid for all the amines; this roughly indicates an average free energy contribution per bond -ΔG⁰ = 4.0 ± 0.2 kJ mol^-1. A slightly more sophisticated equation is also proposed for predicting the stability of these species. Owing to the quite high (partially protonated) phytate charge, the stability of A_p(Phy)H_q^(12-q)- species is quite high, making phytate a strong amine sequestering agent in a wide pH range.     

弱硅化腕足类化石酸处理方法的改进

本文介绍了一种获取灰岩中弱硅化腕足类化石的酸处理方法。以四川省布拖县浪珠乡万吨山剖面上奥陶统铁足菲克组近顶部的生屑灰岩为实验对象, 通过准备样品、悬吊样品、配酸解液、酸解样品等实验流程, 配合遮盖液(如二乙酸纤维素丙酮溶液)的使用, 可获得保存精美的、弱硅化的腕足类实体化石, 且该化石保存有主突起、铰齿和匙形台等重要的细小结构。相较于传统方法, 该方法可获取硅化程度更低的壳相化石。该方法为灰岩中其他多门类弱硅化保存的化石之酸解分析提供了新思路和参考。     

Direct and inverse relationships between Riccati systems coupled with multiplicative terms

An analytical and computational framework for the derivation of solitary solutions to biological systems describing the cooperation and competition of species and expressed by the system of Riccati equations coupled with multiplicative terms is presented in this paper. It is demonstrated that relationships between these solitary solutions can be either direct or inverse. Thus, an infinitesimal perturbation of one population would lead to an infinitesimal change in the other population – if only both solitary solutions are coupled with the direct relationship. But, in general, that is not true if solitary solutions are coupled with the inverse relationship – an infinitesimal perturbation of one population may result into a non-infinitesimal change in the other population. Necessary and sufficient conditions for the existence of solitary solutions are derived in the space of the system's parameters and initial conditions.     

哌拉西林舒巴坦联合莫西沙星治疗社区获得性肺炎的临床观察

目的:探讨哌拉西林舒巴坦与莫西沙星联用治疗社区获得性肺炎的临床效果。方法:随机选取2015年3月--2016年3月在我院呼吸科病区住院的90例社区获得性肺炎患者,并随机分为观察组(28例)、对照A组(31例)对照B组(31例)。观察组患者采用哌拉西林舒巴坦粉针3.75 g,bid,联合莫西沙星0.4 g,静脉注射,qd,对照A组患者则单用哌拉西林舒巴坦粉针3.75 g,静脉滴注,bid,对照B组患者采用单用莫西沙星0.4 g,静脉注射,qd,三组患者的治疗时间均为10 d。治疗结束后,比较两组患者的临床症状改善情况及不良反应的发生情况。结果:治疗10天后,观察组患者治疗后肺部浸润性阴影、肺部啰音、胃肠道情况及体温等均显著好转,观察组患者的临床治疗有效情况显著高于对照A组(100%vs 87.09%,P0.05),对照B组的有效率也较A组提高(96.77%vs 87.09%,P0.05)。观察组总体治愈率显著高于对照A组(92.86%vs 51.61%),对照B组的总体治愈率显著高于对照A组(70.97%vs 51.61%),但观察组和对照B组之间并无显著性差异(p0.05)。观察组、对照A组、对照B组的细菌清除率分别为92.86%、74.19%、90.32%,观察组和对照B组的清除率显著高于对照A组;三组的不良反应发生率比较并无显著性差异(P0.05)。结论:哌拉西林舒巴坦联合莫西沙星治疗社区获得性肺炎的效果显著优于单用哌拉西林舒巴坦治疗的效果,稍优于单用莫西沙星的治疗效果,安全性较高。     

Overcoming Electrode‐Induced Losses in Organic Solar Cells by Tailoring a Quasi‐Ohmic Contact to Fullerenes via Solution‐Processed Alkali Hydroxide Layers

It is shown that the performance of inverted organic solar cells can be significantly improved by facilitating the formation of a quasi‐ohmic contact via solution‐processed alkali hydroxide (AOH) interlayers on top of n‐type metal oxide (aluminum zinc oxide, AZO, and zinc oxide, ZnO) layers. AOHs significantly reduce the work function of metal oxides, and are further proven to effectively passivate defect states in these metal oxides. The interfacial energetics of these electron collecting contacts with a prototypical electron acceptor (C₆₀) are investigated to reveal the presence of a large interface dipole and a new interface state between the Fermi energy and the C₆₀ highest occupied molecular orbital for AOH‐modified AZO contacts. These novel interfacial gap states are a result of ground‐state electron transfer from the metal hydroxide‐functionalized AZO contact to the adsorbed molecules, which are hypothesized to be electronically hybridized with the contact. These interface states tail all the way to the Fermi energy, providing for a highly n‐doped (metal‐like) interfacial molecular layer. Furthermore, the strong “light‐soaking” effect is no longer observed in devices with a AOH interface.     

Comparison of the Morphology Development of Polymer–Fullerene and Polymer–Polymer Solar Cells during Solution‐Shearing Blade Coating

In this work, the detailed morphology studies of polymer poly(3‐hexylthiophene‐2,5‐diyl) (P3HT):fullerene(PCBM) and polymer(P3HT):polymer naphthalene diimide thiophene (PNDIT) solar cell are presented to understand the challenge for getting high performance all‐polymer solar cells. The in situ X‐ray scattering and optical interferometry and ex situ hard and soft X‐ray scattering and imaging techniques are used to characterize the bulk heterojunction (BHJ) ink during drying and in dried state. The crystallization of P3HT polymers in P3HT:PCBM bulk heterojunction shows very different behavior compared to that of P3HT:PNDIT BHJ due to different mobilities of P3HT in the donor:acceptor glass. Supplemented by the ex situ grazing incidence X‐ray diffraction and soft X‐ray scattering, PNDIT has a lower tendency to form a mixed phase with P3HT than PCBM, which may be the key to inhibit the donor polymer crystallization process, thus creating preferred small phase separation between the donor and acceptor polymer.     

Ordered Nanoscale Heterojunction Architecture for Enhanced Solution‐Based CuInGaS2 Thin Film Solar Cell Performance

Nanopatterned CuInGaS₂ (CIGS) thin films synthesized by a sol‐gel‐based solution method and a nanoimprint lithography technique to achieve simultaneous photonic and electrical enhancements in thin film solar cell applications are demonstrated. The interdigitated CIGS nanopatterns in adjacent CdS layer form an ordered nanoscale heterojunction of optical contrast to create a light trapping architecture. This architecture concomitantly leads to increased junction area between the p‐CIGS/n‐CdS interface, and thereby influences effective charge transport. The electron beam induced current and capacitance–voltage characterization further supports the large carrier collection area and small depletion region of the nanopatterned CIGS solar cell devices. This strategic geometry affords localization of incident light inside and between the nanopatterns, where created excitons are easily dissociated, and it leads to the enhanced current generation of absorbed light. Ultimately, this approach improves the efficiency of the nanopatterned CIGS solar cell by 55% compared to its planar counterpart, and offers the possibility of simultaneous management for absorption and charge transport through a nanopatterning process.     

Benchmarking sample preparation/digestion protocols reveals tube‐gel being a fast and repeatable method for quantitative proteomics

Sample preparation, typically by in‐solution or in‐gel approaches, has a strong influence on the accuracy and robustness of quantitative proteomics workflows. The major benefit of in‐gel procedures is their compatibility with detergents (such as SDS) for protein solubilization. However, SDS‐PAGE is a time‐consuming approach. Tube‐gel (TG) preparation circumvents this drawback as it involves directly trapping the sample in a polyacrylamide gel matrix without electrophoresis. We report here the first global label‐free quantitative comparison between TG, stacking gel (SG), and basic liquid digestion (LD). A series of UPS1 standard mixtures (at 0.5, 1, 2.5, 5, 10, and 25 fmol) were spiked in a complex yeast lysate background. TG preparation allowed more yeast proteins to be identified than did the SG and LD approaches, with mean numbers of 1979, 1788, and 1323 proteins identified, respectively. Furthermore, the TG method proved equivalent to SG and superior to LD in terms of the repeatability of the subsequent experiments, with mean CV for yeast protein label‐free quantifications of 7, 9, and 10%. Finally, known variant UPS1 proteins were successfully detected in the TG‐prepared sample within a complex background with high sensitivity. All the data from this study are accessible on ProteomeXchange (PXD003841).