低聚氨基葡萄糖的吸湿、保湿和抑菌性质

采用双氧水在中性条件下对壳聚糖进行氧化降解,制备了低聚氨基葡萄糖,研究了它的吸湿性、保湿性及抗菌性能,结果表明,低聚氨基葡萄糖具有优良的水溶性、吸湿性、保湿性,并对大肠杆菌和绿脓杆菌有较强的抑菌作用。     

GRACE Follow-On revealed Bangladesh was flooded early in the 2020 monsoon season due to premature soil saturation

The overall size and timing of monsoon floods in Bangladesh are challenging to measure. The inundated area is extensive in low-lying Bangladesh, and observations of water storage are key to understanding floods. Laser-ranging instruments on Gravity Recovery and Climate Experiment (GRACE) Follow-On spacecraft detected the peak water storage anomaly of 75 gigatons across Bangladesh in late July 2020. This is in addition to, and three times larger than, the maximum storage anomaly in soil layers during the same period. A flood propagation model suggested that the water mass, as shown in satellite observations, is largely influenced by slow floodplain and groundwater flow processes. Independent global positioning system measurements confirmed the timing and total volume of the flood water estimates. According to land surface models, the soils were saturated a month earlier than the timing of the peak floodplain storage observed by GRACE Follow-On. The cyclone Amphan replenished soils with rainfall just before the monsoon rains started, and consequently, excessive runoff was produced and led to the early onset of the 2020 flooding. This study demonstrated how antecedent soil moisture conditions can influence the magnitude and duration of flooding. Continuous monitoring of storage change from GRACE Follow-On gravity measurements provides important information complementary to river gauges and well levels for enhancing hydrologic flood forecasting models and assisting surface water management.

Water (“mass”) movement on the ground makes the Earth’s gravity field change spatially and temporally, and it also deforms the lithosphere beneath the water load. The dislocated lithosphere, involving solid mass redistribution within the Earth, further changes the Earth’s gravity field. The combined gravity changes from water and solid mass change exerts additional gravitational acceleration and perturbs motions of Earth’s orbiting spacecraft. Such orbital perturbation by water, ice, atmosphere, and/or solid mass movement is subtle and difficult to measure by tracking satellites from ground stations or from global positioning system (GPS) satellites. Instead, the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) spacecraft, launched in 2018, was equipped with onboard microwave instrument (MWI) and laser-ranging interferometer (LRI) systems to measure minute perturbations in distance between two spacecraft to study mass redistribution within the Earth as continuation of its predecessor GRACE (1). Two different ranging systems demonstrated, respectively, the micrometer and nanometer precision of ranging over ∼220 km between two GRACE-FO spacecraft (2).These precise intersatellite ranging measurements together with other auxiliary observations (like nongravitational drag force and spacecraft attitude) are reduced to determine monthly global snapshots of water and ice mass change on the surface and solid mass redistribution within the Earth. These GRACE-FO and GRACE satellites have been providing critical data to study water cycle and climate change by quantifying global mass transport within the Earth system at a monthly scale continuously since 2002 (3). Monthly global data are the primary products from the GRACE-FO project including geopotential fields (Level-2, L2 data) and gridded surface mass (Level-3, L3 data). We developed a method of analyzing instantaneous ranging perturbation (Level-1B, L1B data) to detect rapid changes in a surface water body at a time scale of days to study flooding events and other short-term processes, such as ocean tides, gyres, and tsunamis (4, 5). By using the more accurate LRI data, we are able to better discern short-term signals and thus provide greater temporal sampling of dynamic processes such as flooding.During the wet monsoon season (June through September), a low-lying, coastal country like Bangladesh is prone to regular flooding. Bangladesh is located downstream of the Ganges and Brahmaputra river basins; the total area of these basins is nearly 12 times greater than that of Bangladesh (∼150,000 km²). The heavy rainfall associated with the wet monsoon causes extensive overbank flows along the major rivers of Brahmaputra–Jamuna, Ganges–Padma, and Meghna, accumulated from upstream catchments (SI Appendix, Fig. S1). The northeastern region of the country is also subject to flash floods from torrential rainfall in the Meghalaya plateau. However, the 2020 monsoon flood was not an ordinary one in terms of timing, duration, and severity. It started early, and it was the second longest flood since 1998. It inundated nearly one-third of the country resulting in more than five million people affected and more than one million houses swamped (6). The flood levels measured, for example, at the station Goalondo (the central part of Bangladesh) indicated that the water level was above the “danger” level (i.e., flood threshold) for almost 60 d (SI Appendix, Fig. S2). The first flood wave started in the beginning of July, 2 wk earlier than the historical records of long-lasting floods (7). Such early flooding was not documented in the past (8).It is important to investigate this unusual 2020 monsoon flood to understand possible causes of its untimely onset, magnitude, and dynamics, as such knowledge improves forecasting capability to save people and resources. Bangladesh is a floodplain and riverine country (80% is classified as floodplains). River gauges are useful for understanding channel flow dynamics but not necessarily floodplain and groundwater storage changes. Water storage changes in floodplains are the ones affecting people directly. GRACE-FO gravity measurements (microwave and laser-ranging instruments) are sensitive to water mass movement in groundwater and floodplains as well as channels. In particular, we report an unusual application of the nanometer precision laser ranging measurement from GRACE-FO to examine the size and dynamics of water mass in Bangladesh and hypothesize why the 2020 monsoon flooding started early.     

Moisture Vapor Permeability and Thermal Wear Comfort of Ecofriendly Fiber-Embedded Woven Fabrics for High-Performance Clothing

This study examined the moisture vapor permeability and thermal wear comfort of ecofriendly fiber-embedded woven fabrics in terms of the yarn structure and the constituent fiber characteristics according to two measuring methods. The moisture vapor permeability measured using the upright cup (CaCl₂) method (JIS L 1099A-1) was primarily dependent on the hygroscopicity of the ecofriendly constituent fibers in the yarns and partly influenced by the pore size in the fabric because of the yarn structure. On the other hand, the moisture vapor resistance measured using the sweating guarded hot plate method (ISO 11092) was governed mainly by the fabric pore size and partly by the hygroscopicity of the constituent ecofriendly fibers. The difference between the two measuring methods was attributed to the different mechanisms in the measuring method. The thermal conductivity as a measure of the thermal wear comfort of the composite yarn fabrics was governed primarily by the pore size in the fabric and partly by the thermal characteristics of the constituent fibers in the yarns. Lastly, considering market applications, the Coolmax^®/Tencel sheath/core fabric appears useful for winter warm feeling clothing because of its the good breathability with low thermal conductivity. The bamboo and Coolmax^®/bamboo fabrics are suitable for summer clothing with a cool feel because of their high thermal conductivity with good breathability. Overall, ecofriendly fibers (bamboo and Tencel) are of practical use for marketing environmentallyfriendly high-performance clothing.     

Experimental Investigation of Moisture Sensitivity and Damage Evolution of Porous Asphalt Mixtures

Porous asphalt (PA) mixtures are designed with a high air void (AV) (i.e., 18~22%) content allowing rainwater to infiltrate into their internal structures. Therefore, PA mixtures are more sensitive to moisture damage than traditional densely graded asphalt mixtures. However, the moisture damage evolution of PA mixtures is still unclear. The objective of this study was to investigate the moisture damage evolution and durability damage evolution of PA mixtures. The indirect tensile test (ITT), ITT fatigue test, and Cantabro loss test were used to evaluate the moisture sensitivity and durability of PA mixtures, and a staged ITT fatigue test was developed to investigate the damage evolutions under dry and wet conditions. Indirect tensile strength (ITS), fatigue life, indirect tensile resilience modulus (E), and durability decreased with the increment of moisture damage and loading cycles. The fatigue life is more sensitive to the moisture damage. The largest decrements in ITS and E were found in the first 3000 loading cycles, and PA mixtures tended to fail when the decrement exceeded 60%. Damage factors based on the ITS and E are proposed to predict the loading history of PA mixtures. The durability damage evolution and damage factors could fit an exponential model under dry conditions. Moisture had a significant influence and an acceleration function on the moisture damage evolution and durability damage evolution of PA mixtures.     

小儿肾病常见病理因素探讨

小儿肾病在中医属"本虚标实"之证,多由先天禀赋不足引起,以肺、脾、肾3脏亏虚为本,外感、水湿、湿热、瘀血等邪实为标,两者贯穿其中。而后者又可进一步加重本病的发生,是造成小儿肾病发生、发展、缠绵难愈的基本病理变化,与其病情变化有着密切的关系。     

复方楂金颗粒喷雾干燥工艺研究

目的:对复方楂金颗粒剂的喷雾干燥工艺进行优化。方法:以含水量为指标,优选加入浸膏粉的辅料;采用正交设计法,以复方中含水率、得粉率和绿原酸含量作为指标,确定最佳工艺条件。结果:加入3%的微粉硅胶可以降低含水率,同时能较好地改善浸膏的粘壁情况;最佳工艺参数为进/出风温度190℃/95℃、进料速度80mL/h、浸膏相对密度1.065。结论:该工艺合理,为工业化生产提供了依据。     

姜黄丸水分含量测定近红外定量模型的建立

目的: 运用近红外光谱(NIR)技术对姜黄丸水分进行快速测定。方法: 采集不同批次姜黄丸样品的近红外光谱图,结合OPUS软件进行预处理,在7 552.3~6 707.5 cm^-1,6 699.8~5 538.8 cm^-1,5 515.7~4 204.3 cm^-1谱段内,选择8个主成分,采用偏最小二乘法(PLS)建立姜黄丸水分近红外定量模型。结果: 所建模型相关系数(R²)为0.998 6,交互验证均方根偏差(RMSECV)为0.233,仪器精密度及样品重复性良好,所建模型可以准确测出姜黄丸水分含量。结论: 该方法具有快速、准确、简便的特点,可以用于大批量姜黄丸水分含量的快速在线检测。     

近红外光谱法快速测定逍遥丸(浓缩丸)中水分含量

目的: 应用近红外光谱法建立一种逍遥丸(浓缩丸)中水分含量的快速测定方法。方法: 利用烘干法测定样品中水分含量,并以其作为参考值,运用偏最小二乘法(PLS)建立水分含量与近红外光谱之间的多元校正模型,对未知样品进行含量预测。结果: 所建水分定量分析模型的相关系数(R²),校正均方差(RMSEC),预测均方差(RMSEP)分别为0.953 52,0.132,0.177。结论: 方法操作简便,无污染,结果准确可靠,可用于逍遥丸(浓缩丸)中水分含量的快速测定。     

含水量对膏滋成品保存期限的影响

目的:考察含水量对膏滋成品质量的影响.方法:按传统浓缩、收膏工艺加工生产膏滋成品,测定含水量,根据2010年版《中国药典》附录XⅢC微生物限度检查方法考察不同含水量对膏方微生物学的影响.结果:含水量对膏滋成品的微生物学影响显著,随含水量的增加,产生菌落,膏滋的稳定性降低.结论:通过严格控制膏滋的含水量,可有效地避免膏滋变硬、霉变等现象,保证膏滋成品质量同时延长保存期限.     

正交试验法优选黄连浸膏的喷雾干燥工艺

目的:优选黄连浸膏的喷雾干燥工艺。方法:采用L9(34)正交设计法,以喷干粉出粉量、小檗碱含量和含水量为指标,考察进风口温度、出风口温度、浸膏比重对黄连浸膏喷雾干燥工艺的影响。结果:优选的喷雾干燥工艺为进风口温度180℃,出风口温度80℃,浸膏比重1.15。结论:该优选工艺合理、稳定,可为黄连的工业化生产提供实验依据。