Preparation and characteristics of moulded biodegradable cellulose fibers/MPU-20 composites (CFMCs) by steam injection technology

In this work, the moulded cellulose fibers/MPU-20 composites (CFMCs) with apparent specific gravity lower than 100 kg/m³ and thickness of 20–200 mm have been successfully manufactured using a new design of steam injection technology and equipment. It was found that the CFMCs have good cushioning properties, with a cushion factor lower than 4. Two yield deformation stages were observed in the compressive process. Compressive stress–strain and cushion factor-stain curves were measured as a function of steam injection pressure, transmission time, holding time, MPU-20 resin dosage and apparent specific gravity. Chemical groups, crystallinity, and thermal properties of samples were studied through the use of FTIR spectroscopy, X-ray diffraction (XRD), and DTA–TGA. In addition, the microstructure and morphology were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM).     

Synthesis and physicochemical characterization of oxo and phenylimido Re(V), Re(III) and Ni(II) complexes with the 2-[bis(ethoxyethyl)phosphino]phenolato ligand and derivatives

2-[Bis(ethoxyethyl)phosphino]phenol P¹-OH reacts in basic refluxing solvents with ReOCl₃(PPh₃)₂, in a 2/1 molar ratio, to give the green ReOCl(P¹-O)₂ complex. Structure elucidation by ³¹P NMR is consistent with a cis-PP “twisted” octahedral complex, which is the preferred conformation on electronic grounds. The complex is unique in toluene while several species were present in ethanol. When the reaction is performed with Re(NPh)Cl₃(PPh₃)₂, a mixture of trans-PP (major) and cis-PP(minor) species in a 3/1 ratio is obtained. These geometric isomers were distinguished by their ²J_PP coupling constants. Only cis-PP-Re(NPh)Cl(P¹-O)₂, less soluble, could be isolated and its molecular structure determined by physicochemical measurements. This is the first example of cis-PP phosphinophenolato complex with the [ReNPh]³⁺ core, thus illustrating the importance of the steric demand of the phosphine substituent. Reaction of P¹-OH with NiCl₂ gives Ni(P¹-O)₂ as an orange oily solid with a cis-PP square planar structure. This structure is the most probable based on the ³¹P, ¹³C NMR data.     

Starch modification by iterated syneresis

Potato, tapioca, corn and wheat starches were solubilised in water and isolated from the solution by iterated syneresis and the effect of this physical modification on the physicochemical properties and structure was studied. The experimental starches were examined by chemical analysis, the Brabender rheological method, scanning electron or light microscopy, X-ray diffractometry, infrared spectroscopy, and differential scanning calorimetry. Physical modification was evidenced to the change starch–water interaction and the structure of starches. Pasting temperature shifted to lower values and the gelatinisation mechanism changed. All modified starches had a B-type of X-ray diffraction pattern. The melting temperature of starch crystallites was typical of retrograded starch, but the enthalpy change was higher. The correlation between the resistant starch content of modified starches and their crystal structure was discussed together with the thermal properties.     

基于氨基酸约化和统计特征的蛋白质亚细胞定位预测

蛋白质亚细胞定位预测对蛋白质的功能、相互作用及调控机制的研究具有重要意义。本文基于物化性质和结构性质对氨基酸的约化,描述序列局部和全局信息的"组成"、"转换"和"分布"特征,并利用氨基酸亲疏水性的数值统计特征,提出了一种新的蛋白质特征表示方法(NSBH)。分别使用三种分类器KNN、SVM及BP神经网络进行蛋白质亚细胞定位预测,比较了几种方法和特征融合方法的预测结果,显示融合特征表示及结合SVM分类器时能够达到更好的预测准确率。同时,还详细讨论了不同参数对实验结果的影响,具体的实验及比较结果显示了该方法的有效性。     

Effects of culinary treatments on the physicochemical properties of Ulva lactuca collected from Tabuk coast of Red sea in Saudi Arabia

The increasing demand for healthy, natural, and sustainable food led scientists to take advantage of marine resources and promote interest in culinary and the use of algae that give a variety of colours, textures and flavours from the seaweed. However, few studies have been done on the effect of culinary treatments. Therefore, the aim of the present study is to evaluate the effect of the most popular culinary treatments (boiled, steamed and sous vide) on the physicochemical properties of Ulva lactuca. The treatments were applied at temperatures of 100 °C in the case of both boiling and steaming whereas 50 and 75 °C on sous vide culinary. Results illustrated that both the chemical composition and physical properties of Ulva lactuca greatly affected depending on the culinary method and time. The culinary processes produce an increase in water activity (0.962–0.989) with respect to the raw algae (0.952). All the applied culinary treatments showed an increase in the content of pH, chlorophylls and carotenoids compared to the raw algae, and the highest rise was after boiling for 5 min, although this effect decreases slightly at longer times of boiling. The same about ash, protein, fat, minerals (K, Ca, and Mg), and poly unsaturated fatty acids (PUFAs) boiling is a culinary method that greatly influences and on the contrary, sous vide culinary is a technique that respects and can even improve the nutritional value of raw algae.     

Monitoring of microbial adhesion and biofilm growth using electrochemical impedancemetry

Electrochemical impedance spectroscopy was tested to monitor the cell attachment and the biofilm proliferation in order to identify characteristic events induced on the metal surface by Gram-negative (Pseudomonas aeruginosa PAO1) and Gram-positive (Bacillus subtilis) bacteria strains. Electrochemical impedance spectra of AISI 304 electrodes during cell attachment and initial biofilm growth for both strains were obtained. It can be observed that the resistance increases gradually with the culture time and decreases with the biofilm detachment. So, the applicability of electric cell-substrate impedance sensing (ECIS) for studying the attachment and spreading of cells on a metal surface has been demonstrated. The biofilm formation was also characterized by the use of scanning electron microscopy and confocal laser scanning microscopy and COMSTAT image analysis. The electrochemical results roughly agree with the microscope image observations. The ECIS technique used in this study was used for continuous real-time monitoring of the initial bacterial adhesion and the biofilm growth. It provides a simple and non-expensive electrochemical method for in vitro assessment of the presence of biofilms on metal surfaces.     

Techniques for physicochemical characterization of nanomaterials

Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics.     

高温杀菌对预浸泡豆杆的杀菌效果及品质影响

本研究以预浸泡豆杆为研究对象,研究高温杀菌对预浸泡豆杆中微生物的杀灭效果及其品质的影响,以期获得具有良好感官品质和理化品质的产品。结果表明:当温度≥105℃和时间≥10 min时,样品的菌落总数由初始的8.72×108cfu/g减少到50 cfu/g以内,样品的大肠菌群从1.6×105MPN/g减少到3 MPN/g以内,致病菌均未检出。杀菌温度和杀菌时间对预浸泡豆杆中脂肪含量、pH、弹性影响差异不显著(p>0.05),对水分含量、蛋白质、色差、硬度和咀嚼性影响显著(p<0.05),综合微生物、理化指标、色泽、质构的变化结果,经105℃、15 min和110℃、10 min处理后的预浸泡豆杆既能满足产品卫生要求也可以较好的保留产品原有的品质。     

Decreasing acidity in a series of aldose reductase inhibitors: 2-Fluoro-4-(1H-pyrrol-1-yl)phenol as a scaffold for improved membrane permeation

Targeting long-term diabetic complications, as well as inflammatory pathologies, aldose reductase inhibitors (ARIs) have been gaining attention over the years. In the present work, in order to address the poor membrane permeation of previously reported ARIs, derivatives of N-phenylpyrrole, bearing groups with putative pK_a ⩾ 7.4, were synthesized and evaluated for aldose reductase inhibitory activity. The 2-fluorophenol group proved the most promising moiety, and further modifications were explored. The most active compound (31), identified as a submicromolar inhibitor (IC₅₀ = 0.443 μM), was also selective against the homologous enzyme aldehyde reductase. Cross-docking revealed that 31 displays a peculiar interaction network that may be responsible for high affinity. Physicochemical profiling of 31 showed a pK_a of 7.64, rendering it less than 50% ionized in the physiological pH range, with potentially favorable membrane permeation. The latter was supported from the successful inhibition of sorbitol formation in rat lenses and the ability to permeate rat jejunum.