Exploration of nanofiltration conditions for separation of alcohol precipitation liquid during preparation of Reduning Injection by Box-Behnken design combined with flux attenuation / 中国中药杂志

This study employed Box-Behnken design combined with flux attenuation to explore the nanofiltration conditions for separation of alcohol precipitation liquid during the preparation of Reduning Injection and discussed the applicability of nanofiltration in the separation of the liquid with high-concentration ethanol. The effects of nanofiltration molecular weight cut-off(MWCO) and pH on the rejection of chlorogenic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid were consistent with the principles of pore size sieving and charge effect, respectively. The rejection of the three phenolic acids was reduced by concentration polarization effect caused by trans-membrane pressure(TMP). The swelling of membrane surface decreased the pore size and membrane flux for effective separation. Chlorogenic acid and 4,5-dicaffeoylquinic acid were more sensitive to pH and ethanol concentration than 3,5-dicaffeoylquinic acid. A certain correlation existed between the compound structure and the separation factors of nanofiltration, and the separation rules were associated with the comprehensive effect of charge effect, pore size sieving, concentration polarization, steric hindrance and so on.

Ultra-light poly(lactic acid)/SiO2 aerogel composite foam: A fully biodegradable and full life-cycle sustainable insulation material.

In this study, a fully biodegradable ultra-light poly(lactic acid)/silicon dioxide (PLA/SiO2) aerogel nanocomposite with ultra-low thermal conductivity was successfully fabricated. PLA used was a produced from lactic acid, where the lactic acid has been produced from carbohydrates. The rheological properties of PLA were enhanced by diphenylmethane diisocyanate (MDI). The foaming properties, cell density, cell size uniformity, mechanical properties and thermal conductivity and thermal diffusivity of PLA were further improved by SiO2 aerogel, and finally the ultra-low density foamed material was prepared by supercritical CO2. The density of PLA foam can be as low as 0.02 g/cm3 and the thermal conductivity as low as 0.02628 W/m·K. The PLA-based composites can be used in many fields such as thermal insulation, vibration damping and packaging, and can be fully biodegradable and sustainable throughout their life cycle, which meets the global trend of energy saving and emission reduction.

A series of sequences convergent to Euler's constant.

In this paper, using continued fraction, we provide a new quicker sequence convergent to Euler's constant. We demonstrate the superiority of our new convergent sequences over DeTemple's sequence, Mortici's sequences, Vernescu's sequence, and Lu's sequence.

Clinical features of gastroesophageal reflux disease in geriatric patients / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the features of gastroesophageal reflux disease (GERD) in elderly patients.</p><p><b>METHODS</b>72 patients with GERD were investigated for the history of illness and the results of gastroscopy and 24 hours esophageal bile monitoring of 54 patients were simultaneously randomized to undergo ambulatory pH monitoring. The degrees of esophagitis were graded according to endoscopic findings.</p><p><b>RESULTS</b>Obesity was found in 48% of the elderly group (more than 65 years old) and 49% of the control group (less than 65 years old). There were longer acid and bile reflux time and higher frequency (65%) of hiatal hernia in the elderly, and more patients (35%) had complicated severe grade esophagitis. There were longer time of bile reflux and the higher incidence (76%) of both acid and bile reflux in elderly group than in control group (P < 0.05). But the acid reflux time (%) was similar in two groups (P > 0.05).</p><p><b>CONCLUSIONS</b>The GERD in elderly patients may be associated with obesity and hiatal hernia. The features of elderly GERD patients are high frequency of erosive esophagitis, and high frequency of both acid and bile reflux, as well as longer history of bile reflux time.</p>