无机盐对聚乙二醇(PEG)水溶液浊点温度的影响

<正> 聚乙二醇(Polyethylenylycol,PEG)是一种线型水溶性大分子,广泛用于造纸工业的粘着剂,纤维工业的上浆材料,它在生物体内的原生质融合过程中起着重要作用。因其分子结构简单,且不荷电,所以它对研究大分子水溶液中的结构效应是很有益的,无机盐的加入可以改变PEG溶液体系的相转移温度。Baily和Callard,曾研究过无机盐对PEG水溶液浊点温度的影响。本研究除进一步系统考察这种影响外,还讨论了它们之间的规律性,并且确定了PEG+H_2O体系的下临界共溶温度。     

Polymer-Coated Fibrous Packing Materials in Metal Capillary Gas Chromatography

Gas chromatography (GC) is one of the most versatile separation methods for volatile compounds, and a variety of polymeric materials as the stationary phases have been developed for various applications. In contrast to the successful applications and commercialization of the polymer-coated columns, the reports for the fibrous     

Early Pulmonary Rehabilitation with Neuromuscular Electrical Stimulation in a Patient with Acute Exacerbation of Rheumatoid Arthritis-associated Interstitial Lung Disease: A Case Report

Introduction: Early implementation of neuromuscular electrical stimulation (NMES) has been reported to prevent muscle atrophy and physical functional decline in patients requiring mechanical ventilation. However, its effect in patients with acute exacerbation of interstitial lung disease (ILD) remains unclear. We herein report our experience using the NMES combined with mobilization in a patient with an acute exacerbation of rheumatoid arthritis-associated ILD (RA-ILD) requiring mechanical ventilation. Case Presentation: A 74-year-old man was admitted to the intensive care unit (ICU) and put on mechanical ventilation due to severe acute exacerbation of RA-ILD. Early mobilization and the NMES using a belt electrode skeletal muscle electrical stimulation system were started on day 7 of hospitalization (day 2 of ICU admission). The NMES duration was 20 min, performed once daily. The patient could perform mobility exercises on day 8 and could walk on day 16. We assessed his rectus femoris and quadriceps muscle thicknesses using ultrasound imaging, and found decreases of 4.5% and 8.4%, respectively, by day 14. On day 27, he could independently visit the lavatory, and the NMES was discontinued. He was instructed to start long-term oxygen therapy on day 49 and was discharged on day 63. His 6-minute walk distance was 308 m and his muscle thickness recovered to levels comparable to those at the initial evaluation at the time of discharge. Conclusion: Combining the NMES and mobilization started in the early phase and continued after ICU discharge was safe and effective in a patient with a severe acute exacerbation of RA-ILD.     

Pain in Spinal Muscular Atrophy: A Questionnaire Study

Objective: This study aimed to reveal the chronic pain prevalence in spinal muscular atrophy (SMA) patients and identify the clinical characteristics of these patients with chronic pain. The pain status was also investigated in SMA patients with chronic pain. Methods: This cross-sectional study was conducted between July 2018 and December 2018. SMA type II and type III patients in Japan were mailed a survey questionnaire. The survey items were chronic pain prevalence, clinical characteristics, and motor function. Patients with chronic pain also answered questions on various pain status parameters: pain intensity, frequency, duration, location using body map, and factors that exacerbated and relieved pain. Results: The questionnaire recovery rate was 61.1%. Sixty-four type II (mean age 17.3 ± 11.7 years) and 22 type III (mean age 44.9 ± 21.6 years) patients were eligible for inclusion. The prevalence of chronic pain in type II and III patients was 40.6% and 40.9%, respectively. Type II patients with chronic pain were more likely to report the inability to sit without manual support than those without pain (p = 0.03). Pain intensity in SMA patients was mild, but pain usually occurred daily, for prolonged durations, most often in the neck, back, and lower extremities. Sitting and high physical activity exacerbated pain the most. Conclusion: The percentage of patients with SMA with chronic pain was high, at above 40%. Moreover, the pain experienced by patients with SMA was low in intensity but frequent and most common in the lower extremities.     

Multi-reference configuration interaction calculation of positronium fluoride 2,1S and 2,1P states

Multi-reference configuration interaction calculations for the ground state ^2,1S and an excited state ^2,1P of positronium fluoride (PsF) were performed, and their energies, the positronium (Ps) binding energies and the two-photon positron-electron pair annihilation rates were presented. From an analysis of the convergence pattern of the total energies and the two-photon annihilation rates with respect to the angular momentum of basis functions, an extrapolation method which may give accurate Ps binding energies and two-photon annihilation rates was applied. Estimated Ps binding energy for ^2,1S state of PsF was in good agreement with the recent reliable calculations. The structures of ^2,1S and ^2,1P states of PsF also were predicted from the point of view of the two-photon annihilation rate.     

Influences of chemical modifications on the mechanical strength of cellulose beads

Spherical cellulose beads having narrow particle-size distribution were prepared by the coagulation/regeneration method for small viscose droplets formed by centrifugal force in an acid bath. The influences of chemical modifications on mechanical strengths such as the hydraulic property and compressive strength were investigated, together with the effects on crystallinity, particle size and degree of swelling. Cross-linking with epichlorohydrin and substitution of hydroxyl groups in cellulose with diethylaminoethyl, carboxymethyl and cyanoethyl groups were studied. No remarkable differences were found in X-ray diffraction patterns for the cellulose beads after the chemical modification. The substitution promoted swelling of the beads and decreased the mechanical strength, probably by scission of intermolecular and/or intramolecular hydrogen bonds in cellulose. However, the cross-linking retarded the cellulose beads from swelling effectively. The beads were made significantly ha rder by the substitution, and this hardening effect competed with the softening effect of the swelling. Moreover, it was suggested that the simple compression test was useful for the prediction of the hydraulic property of the cellulose beads in the column operation. 0969--0239 © 1998 Blackie Academic & Professional     

DNA双链断裂的组成与自由基清除效能的关系

ＤＮＡ双链断裂（ＤＳＢ）是重要的辐射生物学效应之一 ,它是导致细胞死亡和变异的主要因素［１,２］．大量研究表明 ,ＤＳＢ由αＤＳＢ和 βＤＳＢ两部分组成 ,分别为电离辐射能量沉积的单击作用 (包括ＬＭＤＳ机制和单自由基传递机制 )和双击作用所致［３ -５］．但对不同的生物体系 ,由于靶体积大小等不一 ,α、β有不同的值．从根本上讲 ,α、β与电离辐射的径迹如粒子的种类、ＬＥＴ等有关 ,α在中等ＬＥＴ时最大 ,而 β则在低ＬＥＴ辐射时占优势［６］．研究α、β 与生物体系之间的关系 ,将有助于加深人们对电离辐射物理化学效应的…     

ChemInform Abstract: Spectroscopic and Electrochemical Characterization of 18-Molybdodisulfate(VI)(4-), S2Mo18O4- 62.

The chemical and physicochemical properties of the yellow Dawson-type molybdosulfate anion S₂Mo₁₈O₆^4-2 in solution are investigated, regarding to the optimum formation conditions, UV-VIS characteristics, and electrochemical behavior.     

ChemInform Abstract: Discrete-Variational-Xα Calculations of Buckminsterfullerene ( C60) and Fulleride X-Ray Emission Spectra

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: The Structure of Amorphous Platinum Disulfide as Studied by Anomalous X-Ray Scattering.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.