Water Status and Predictive Models of Moisture Content during Drying of Soybean Dregs Based on LF-NMR

To explore the drying characteristics of soybean dregs and a nondestructive moisture content test method, in this study, soybean dregs were dried with hot air (80 °C), the moisture content was measured using the drying method, water status was analyzed using low-field nuclear magnetic resonance (LF-NMR) and the moisture content prediction models were built and validated. The results revealed that the moisture contents of the soybean dregs were 0.57 and 0.01 g/g(w.b.), respectively, after drying for 5 and 7 h. The effective moisture diffusivity increased with the decrease in moisture content; it ranged from 5.27 × 10⁻⁹ to 6.96 × 10⁻⁸ m²·s⁻¹. Soybean dregs contained bound water (T₂₁), immobilized water (T₂₂) and free water (T₂₃ and T₂₃’). With the proceeding of drying, all of the relaxation peaks shifted left until a new peak (T₂₃’) appeared; then, the structure of soybean dregs changed, and the relaxation peaks reformed, and the peak shifted left again. The peak area may predict the moisture content of soybean dregs, and the gray values of images predict the moisture contents mainly composed of free water or immobilized water. The results may provide a reference for drying of soybean dregs and a new moisture detection method.     

Increase in the Intracellular Bulk Water Content in the Early Phase of Cell Death of Keratinocytes,Corneoptosis, as Revealed by 65 GHz Near-Field CMOS Dielectric Sensor

While bulk water and hydration water coexist in cells to support the expression of biological macromolecules, how the dynamics of water molecules, which have long been only a minor role in molecular biology research, relate to changes in cellular states such as cell death has hardly been explored so far due to the lack of evaluation techniques. In this study, we developed a high-precision measurement system that can discriminate bulk water content changes of ±0.02% (0.2 mg/cm³) with single-cell-level spatial resolution based on a near-field CMOS dielectric sensor operating at 65 GHz. We applied this system to evaluate the temporal changes in the bulk water content during the cell death process of keratinocytes, called corneoptosis, using isolated SG1 (first layer of stratum granulosum) cells in vitro. A significant irreversible increase in the bulk water content was observed approximately 1 h before membrane disruption during corneoptosis, which starts with cytoplasmic high Ca²⁺ signal. These findings suggest that the calcium flux may have a role in triggering the increase in the bulk water content in SG1 cells. Thus, our near-field CMOS dielectric sensor provides a valuable tool to dissect the involvement of water molecules in the various events that occur in the cell.     

基于溶液温度差谱分析的ATR-FTIR原位测量方法

作为一种原位、快速、无损坏的中红外光谱分析技术,ATR-FTIR已在很多工程领域得到越来越多的应用,尤其是针对结晶过程溶液浓度的原位实时测量。水是一种常用的结晶溶剂,在中红外波段具有强吸收峰,并且在不同温度下具有光谱吸收差异性,因而不能忽略溶剂水和温度对溶液浓度的中红外光谱测量带来的影响。以朗伯-比尔定律为基础,提出采用溶液光谱减去相应温度下的溶剂光谱的方法,从而能准确地测量溶液浓度。以L-谷氨酸溶液结晶过程为例,对L-谷氨酸水溶液的原始光谱数据、溶液光谱扣除常温(25℃)溶剂水的光谱数据以及溶液光谱对应温度扣除溶剂水的光谱数据分别进行建模。结果表明,提出的对应温度差谱法能有效消除溶剂水峰对溶质光谱测量的干扰,明显地降低了溶液浓度光谱标定模型的预测误差。该方法对提高原位ATR-FTIR光谱检测精度的实际应用具有一定的参考价值。     

The Orion Water-Hardness Electrode: An Unexpected Response to Magnesium Ion

Abstract

The Orion water-hardness electrode, while being used to measure magnesium ion activity in a series of calcium-free solutions, displayed some unanticipated changes in potential. As the overall potential change observed for one solution was 183 mV (equivalent to more than six orders of magnitude changes in magnesium-ion activity), several precautions are suggested which should be observed when using this electrode for specific purposes. In particular, it is recommended that the exchanger be pre-equilibrated with an appropriate solution if the electrode is to be used in restricted systems of known chemical composition.     

Die Untersuchung einer Laboratoriumsanlage nach dem Heiß-Kalt-System mit einfachem Durchfluß der Fluide

Es wird ein Heiβ-Kalt-System mit einfachem Durchfluβ der Fluide untersucht. Dabei wird gezeigt, daβ zwischen den Isotopenkonzentrationen des Gases und der Flüssigkeit lineare Beziehungen bestehen. Eine Möglichkeit zur experimentellen Bestimmung der realen Werte der Parameter der Kolonne wird angegeben.     

Facile synthesis of pH‐responsive glycopolypeptides with adjustable sugar density

Well‐defined pH‐responsive glycopolypeptides were prepared by polymer‐analogous aqueous amide coupling of d ‐glucosamine to poly(α,l ‐glutamic acid) (PGA) using the coupling agent 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride (DMT‐MM) without any organic solvents, additives, or buffers. Degrees of substitution (DS) up to 80% can be achieved, and the DS is adjustable by the molar ratio of DMT‐MM to PGA repeating units. Successful glycosylation of both low MW and high MW PGA was confirmed by ¹H NMR and FTIR spectroscopy as well as by an enhanced solubility at low pH. CD spectroscopy revealed that glycosylated PGAs with a DS up to 0.63 are able to undergo a pH‐responsive and reversible helix‐coil transition. However, for polymers with higher DS no transition occurs. A comparison with PGAs functionalized with monoethanolamine showed that the low helicity at high DS is not a steric effect due to the bulky sugar moieties, but a solvation effect. Preliminary turbidimetric tests with the lectin Concanavalin A indicate a biological activity of these glycosylated polypeptides. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3925–3931     

Poly(amidoamine)s: Past,present, and perspectives

Poly(amidoamine)s (PAAs) are a family of synthetic polymers obtained by stepwise polyaddition of prim‐ or sec‐amines to bisacrylamides. Nearly all conceivable bisacrylamides and prim‐ or sec‐amines can be employed as monomers endowing PAAs of a structural versatility nearly unique among stepwise polyaddition polymers. PAAs are degradable in aqueous media, including physiological fluids. Many of them are remarkably biocompatible notwithstanding their cationic character. PAAs are per se highly functional polymers and, in addition, can be further functionalized giving rise to an endless variety of polymeric structures meeting the requisites for applications in such apparently disparate fields as inorganic water pollutants scavengers, sensors, drug and protein intracellular carriers, transfection promoters, peptidomimetic antiviral and antimalarial agents. In this review, the unique chemistry of PAAs is discussed and a vast library of PAA structures and PAA applications from the beginning to the present days reported. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2319–2353     

Sampling and Analysis of Odorous Compounds in Water Treatment Plants

Abstract

The following analytical method has been used to identify some odorous compounds in the air of the water treatment plant Werdholzli, Zurich: sampling of contaminated air with the help of activated carbon, desorption by the solvents carbon disulphide and methylene chloride, separation of the carbon disulfide extract into a polar and a nonpolar fraction by adsorption column chromatography on silica. Hereafter gaschromatographic analysis of the polar fraction on glass capillary column (Ucon HB 5100); detection and identification were achieved by flame ionisation, thermoionic nitrogen selective detector and computerized mass spectrometry (Finnigan 3200 F, data system 6110).

The results show the presence of sulfur compounds: thiophenes, thiazoles; nitrogen compounds: pyrazines; oxygen compounds: phenols, alcohols and some unsatured hydrocarbons. The malodorous compounds were sulfur and nitrogen compounds in the range of 0.01-0.1 ppm.     

GasChromatography of Amino Acids as their N-Trifluoroacetyl Methyl Esters and Comparison with the Ion-exchange Method in Maize and Oats

A method for the preparation of N-trifluoroacetyl methyl esters of amino acids has been developed, permitting the separation and determination of 20 amino acids by temperature-programmed gas chromatography on two columns. The method was applied to the analysis of the amino acids in hydrolyzed maize and in hydrolyzed oats, where a direct comparison was made with the ion-exchange method.     

Solid-Phase Extraction and Capillary Gas Chromatographic Determination of Triazine Herbicides in Water

Abstract

A facile and efficient method is described for the determination of trace quantities of triazine herbicides, terbutryn, prometryn and ametryn in water. The procedure involved preconcentration of water samples by sorption on chromatographic grade silica gel particles with chemically modified surface, being covalently bonded with a nonofunctional C₈H₁₇ group. This was followed by solvent desorption with 2-propanol. The determinative step was achieved by capillary gas chromatography on Supelcowax-10 fused silica column using a nitrogen-phosphorus detector. The limit of detection was 0.1 μg-10 μgL^?1.