水凝胶的改性及其在生物医学中的 应用研究进展

水凝胶的改性是水凝胶在多方面获得应用的前提条件。本文重点综述了几类水凝胶的改性及其应用进展,包括聚乙烯醇(PVA)和明胶复合水凝胶、蛋白质水凝胶、新型智能水凝胶以及纳米水凝胶。同时指出要密切关注改性水凝胶的生物相容性、成本价格、生物可降解性、适用范围,使更多水凝胶能走向临床,获得更广泛的应用。

Effects of Cultivation Method on Seed Yield and Quality of Bitter Gourd

This experiment was carried out to study the possibility of producing germinating seeds of bitter gourd(Momordica charamtia L.)in the climatic conditions of Europe.Seeds of Indian cultivar‘Nana’were sown in the greenhouse and produced transplants were planted on the field.The plants were cultivated in the field in 2 ways:tied to the sticks or creeping on the ground.During the vegetation,the ripen fruits with seeds were collected 6 times,and after extracting,they were germinated in the laboratory following the routine ISTA rules.The best transplants of bitter gourd were received within one month from the seeds emerging 51.8%.The transplant of bitter gourd had average height of7 cm,3-4 leaves,out of which the biggest had the width of 5 cm.Such transplants would grow into fruiting plants.When growing bitter gourd for seeds,the earliest fruits were harvested from the plants tied to the sticks.Moreover,the best seeds were harvested from 2/3 of early fruits.For the purpose of seed production,it is recommended to keep only 3-4 fruits per plant and remove other fruits.The produced seeds germinated from 8%to 24%.If the plants were tied to the sticks,their fruits ripened earlier.The used production way and time of harvest of fruits had no effect on the seed germination.The cultivation methods of bitter gourd plants had no effect on the chemical components of fruits.

Morphology and Thermal Characteristics of Polysaccharide Extracted by Ultrasound from <i>Ophiopogon japonicas</i>

The crude polysaccharide UPOJ was extracted by ultrasound from Ophiopogon japonicas and purified by DEAE-cellulose52 column and Sephadex G-150 gel column. Purified polysaccharide UPOJ-DS was obtained. The thermal characteristics of UPOJ-DS were studied by using the thermal analysis system Q1000DSC LNCS FACS Q600SDT. The heating rate was 10&deg;C/min and the test temperature was 20&deg;C ~ 800&deg;C. The results showed that there were three large mass losses in the process of heating, in which the maximum weight loss rate was 66.68% at 220&deg;C ~ 330&deg;C and the decomposition reaction took place in the polysaccharide itself, which indicated that the composition, water content, intermolecular interaction and aggregation behavior of UPOJ-DS were affected by temperature. The surface morphology of UPOJ-DS was observed by environmental scanning electron microscope (ESEM). The results indicated that the polysaccharide molecules were lamellar or clastic, with smooth surface, strong intermolecular interaction and close binding.

Antioxidant Activity <i>in Vitro</i>of Polysaccharide Extracted by Ultrasound with Different Powers from <i>Ophiopogon japonicas</i>

The polysaccharides were extracted by different power ultrasound from Ophiopogon japonicas. The extraction yield and in vitro antioxidant activities including scavenging effect on hydroxyl radical, superoxide anion free radicals and DPPH were investigated. The results showed that with the increase of ultrasonic power, the yield of the polysaccharides decreased first and then increased. The antioxidant activity of polysaccharides increased first and then decreased with the increase of ultrasonic power. When the power was 400 W, the scavenging effect on superoxide anion and DPPH of the polysaccharides was the strongest, and the scavenging ability of hydroxyl radical was the strongest when the power was 560 W. Therefore, different ultrasonic power could affect the extraction yield and antioxidant activity of Ophiopogon japonicas polysaccharide. It will provide theoretical basis and experimental support for the application of ultrasonic extraction on polysaccharides from Ophiopogon japonicas.

Preparation of Intelligent Supramolecular Hydrogels and Its application as 3D culture scaffold of ovarian cancer cell

Destination:to prepare intelligent suparmolecular hydrogel by mimicking the key features of extracellular matrices(ECM)and culture ovarian cancer cells in 3D mold,then investigate the influence of microenvironments on behavior of cells.Method:Through using the inclusion complexes interact between trans-azobenzene(or adaman-

32×32 NbN SNSPD array based on thermally coupled row-column multiplexing architecture

We report a superconducting nanowire single‐photon detector(SNSPD)array aiming for a near‐infrared 1550‐nm wavelength that consists of 32×32 nanowire pixels and an area of 0.96 mm×0.96 mm.Unlike most reported large‐scale SNSPD arrays with amorphous films,NbN superconducting nanowires are employed in our array,which allows the detector operation at 2.3 K provided by a compact two‐stage Gifford–McMahon cryocooler.Thermally coupled row–column multiplexing is employed in our arrays to avoid current redistribution and loss of electrical signal occurring in the electrically coupled row–column architecture.The fabricated detector array shows a pixel yield of 94%and maximal intrinsic efficiencies of 77%and 96%at 1550 nm and 405 nm,respectively.The timing jitter and the thermal coupling probability are also investigated.

Sinks of steel in China-addition to in-use stock, export and loss

China has become the largest producer of crude steel in the world since 1996, which places the country under huge pressure in terms of resources, energy, and the environment. Examining the driver of steel demand is of great significance to the structural adjustment and sustainable development of the steel industry. The researchers calculate the steel demand in China from 2000 to 2009 based on three sinks （steel stock, export, and loss） by taking the four stages of steel life cycle （production, fabrication and manufacturing, use, and waste manage- ment and recycling） as the study object. The researchers conclude that addition to in-use stock is the main driver of steel demand and that the 10-year average addition to in- use stock accounted for 77% of the steel sinks, in which 55% of the addition occurs in the building sector, and the steel for this segment is of low strength with large consumption. Based on the analysis of existing policies, the researchers propose that the steel demand structure will develop toward diversification and that the building sector will realize the upgrade of products as soon as possible to improve construction quality. Under the pressure of rising cost for imported resources, the export ratio of steel products should be controlled appropriately. Thus, recy- cling economy should be developed to reduce steel losses.

Clinical Manifestation and Laboratory Characteristics of SARS-CoV-2Infection in Pregnant Women

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) epidemic has become a major challenge to public health in China and other countries, considering its pathogenicity across all age groups. Pregnancy is a unique physiological condition, and is characterized by altered immunity and elevated hormone levels to actively tolerate the semiallogeneic fetus, which undergoes a sudden and substantial fluctuation during the immediate postpartum period. Changes in clinical features, laboratory characteristics, and imaging features of pregnant women during the pre-partum and postpartum periods require further elucidation. Here, we retrospectively analyzed the clinical features, laboratory characteristics, and imaging features of eight pregnant cases of SARS-CoV-2 infection during the pre-partum and post-partum periods. Our results showed that four of the eight pregnant women were asymptomatic before delivery but became symptomatic post-partum. Correspondingly, white blood cell(WBC) counts increased and lymphocyte(LYMPH) counts decreased. C-reactive protein(CRP) levels in the serum also increased to a higher level than those in general pregnancy.Therefore, it is imperative to closely monitor laboratory parameters including the WBC count, LYMPH count, and CRP,along with other imaging features in chest CT scans, to promptly prevent, diagnose, and treat a SARS-CoV-2 infection during pregnancy.

Defects inducing anomalous exciton kinetics in monolayer WS_(2)

Two-dimensional(2D)transition metal dichalcogenide(TMD)has emerged as an effective optoelectronics material due to its novel optical properties.Understanding the role of defects in exciton kinetics is crucial for achieving high-efficiency TMD devices.Here,we observe defects induced anomalous power dependence exciton dynamics and spatial distribution in hexagonal heterogeneous WS_(2).With transient absorption microscopy study,we illustrate that these phenomena originate from the competition between radiative and defect-related non-radiative decays.To understand the physics behind this,a decay model is introduced with two defect-related channels,which demonstrates that more excitons decay through non-radiative channels in the dark region than the bright region.Our work reveals the mechanisms of anomalous exciton kinetics by defects and is instrumental for understanding and exploiting excitonic states in emerging 2D semiconductors.

Highly flexible Nyquist pulse generation based on multi-wavelength control

By controlling the wavelength and power of multiple light sources, we have realized a highly flexible Nyquist pulse generation scheme, in which the pulse repetition frequency, pulse multiplication factor, waveform envelope shape, and duty cycle are all tunable. By modulating the 3.2 GHz RF signal, we experimentally generated Nyquist pulses with repetition rates of 6.4 GHz and 9.6 GHz, a rectangular wave with a duty cycle of 0.26,and a sawtooth wave with a duty cycle of 0.52.

妙造天成始自然

2017“世界最美的书”评选近日在德国莱比锡揭晓，一本特别的书——《虫子书》当选为银奖作品。这本《虫子书》由著名装帧设计师朱赢椿所设计，全书没有一个汉字，完全由虫子们自然创作而成。设计师数年来与工作室的各色虫子朝夕相处，收集它们在叶子上啃咬或纸张上爬行后留下的痕迹，点线之间，竟有书法的气韵，妙趣写意、浑然天成。