综合性高分子化学实验设计:硬质聚氨酯泡沫材料制备与性能表征

针对传统“高分子化学实验”课程教学中,存在综合性、研究性实验项目少,不能支撑“新工科”人才实践和创新能力培养要求等问题,开发了硬质聚氨酯泡沫材料制备与性能表征综合实验项目。采用全水发泡体系,通过调节发泡剂和阻燃剂用量,制备了七组聚氨酯泡沫材料,然后采用国标方法表征了材料的表观密度、压缩强度和氧指数,分析了发泡剂和阻燃剂不同配比对泡沫材料性能的影响及原因。本实验贴近高分子产业发展,突出综合性和研究性,教学过程实现了基本实验技能与科学研究方法训练的有机结合,有助于提升高分子化学实验课程“创新性、高阶性和挑战度”,支撑“新工科”人才培养。

Photodynamic Therapy Combined with Electrosurgical Resection for Recurrent Bladder Cancer

Bladder tumor is characterized by recurrent recurrence and distant metastasis,which determines the difficulty of completely curing bladder tumor.In recent years,the number of patients with bladder cancer is increasing,and the treatment of bladder cancer has become an important direction of clinical research.It is difficult to control bladder tumor by traditional therapy.Photodynamic therapy(PDT),as a new optical therapy,has gradually become the main method in clinical treatment of bladder tumor combined with transurethral resection of bladder tumor.In this paper,a patient with superficial recurrent bladder tumor was treated by photodynamic therapy combined with transurethral resection of bladder tumor.The advantages of photodynamic therapy in the treatment of bladder tumor and the selection of photosensitizer in the process of photodynamic therapy were discussed.After two recurrences,the patients chose photodynamic therapy.The tumors were resected one by one,and the wound was coagulated by roller electrode.After the drug was retained for 20 minutes,the bladder was empty.The spherical optical fiber was implanted into the bladder.The photodynamic energy was adjusted(light power 1.8 W,light time 1302 s).There was no recurrence after operation.Most bladder tumors are superficial tumors,and bladder is a cavity organ,which determines that bladder is an ideal organ for photodynamic therapy.As a targeted drug,photosensitizer is only absorbed by bladder tumor after being perfused into bladder.The photosensitizer forms reactive oxygen species through oxygen and kills tumor cells.Clinical practice has proved that PDT has its unique advantages for superficial and recurrent bladder tumors.As the first generation photosensitizer,xipofen also has selectivity in the treatment of bladder cancer.

GPRC5B protects osteoarthritis by regulation of autophagy signaling

Osteoarthritis(OA)is one of the most common chronic diseases in the world.However,current treatment modalities mainly relieve pain and inhibit cartilage degradation,but do not promote cartilage regeneration.In this study,we show that G protein-coupled receptor class C group 5 member B(GPRC5B),an orphan G-protein-couple receptor,not only inhibits cartilage degradation,but also increases cartilage regeneration and thereby is protective against OA.We observed that Gprc5b deficient chondrocytes had an upregulation of cartilage catabolic gene expression,along with downregulation of anabolic genes in vitro.Furthermore,mice deficient in Gprc5b displayed a more severe OA phenotype in the destabilization of the medial meniscus(DMM)induced OA mouse model,with upregulation of cartilage catabolic factors and downregulation of anabolic factors,consistent with our in vitro findings.Overexpression of Gprc5b by lentiviral vectors alleviated the cartilage degeneration in DMM-induced OA mouse model by inhibiting cartilage degradation and promoting regeneration.We also assessed the molecular mechanisms downstream of Gprc5b that may mediate these observed effects and identify the role of protein kinase B(AKT)-mammalian target of rapamycin(m TOR)-autophagy signaling pathway.Thus,we demonstrate an integral role of GPRC5B in OA pathogenesis,and activation of GPRC5B has the potential in preventing the progression of OA.

Internet of Things to network smart devices for ecosystem monitoring

Smart, real-time, low-cost, and distributed ecosystem monitoring is essential for understanding and managing rapidly changing ecosystems. However, new techniques in the big data era have rarely been introduced into operational ecosystem monitoring, particularly for fragile ecosystems in remote areas.We introduce the Internet of Things(IoT) techniques to establish a prototype ecosystem monitoring system by developing innovative smart devices and using IoT technologies for ecosystem monitoring in isolated environments. The developed smart devices include four categories: large-scale and nonintrusive instruments to measure evapotranspiration and soil moisture, in situ observing systems for CO2 and d13 C associated with soil respiration, portable and distributed devices for monitoring vegetation variables, and Bi-CMOS cameras and pressure trigger sensors for terrestrial vertebrate monitoring. These new devices outperform conventional devices and are connected to each other via wireless communication networks. The breakthroughs in the ecosystem monitoring IoT include new data loggers and longdistance wireless sensor network technology that supports the rapid transmission of data from devices to wireless networks. The applicability of this ecosystem monitoring IoT is verified in three fragile ecosystems, including a karst rocky desertification area, the National Park for Amur Tigers, and the oasis-desert ecotone in China. By integrating these devices and technologies with an ecosystem monitoring information system, a seamless data acquisition, transmission, processing, and application IoT is created. The establishment of this ecosystem monitoring IoT will serve as a new paradigm for ecosystem monitoring and therefore provide a platform for ecosystem management and decision making in the era of big data.

基于模板导向的共价卟啉笼和纳米环的合成与应用

模板导向策略是构建复杂有序结构的高效方法,极大地促进了共价多卟啉笼和纳米环的合成.金属卟啉前体借助其中心金属与所选择的模板之间的配位作用形成预组织结构,然后通过共价键连接各组分以构筑卟啉笼或纳米环结构.虽然无模板作用下也能够构建得到共价卟啉笼或纳米环,但模板导向法明显更具优势,特别是在较大尺寸的多卟啉纳米环的合成中体现了其高效性.本文综述了近年来具有不同拓扑结构的共价卟啉笼和纳米环的合成及其在主客体化学、人工光合作用、仿生催化、纳米药物等方面的应用,并展望了其未来发展前景.

Molecular dynamics simulation of graphene sinking during chemical vapor deposition growth on semi-molten Cu substrate

Copper foil is the most promising catalyst for the synthesis of large-area,high-quality monolayer graphene.Experimentally,it has been found that the Cu substrate is semi-molten at graphene growth temperatures.In this study,based on a self-developed C–Cu empirical potential and density functional theory(DFT)methods,we performed systematic molecular dynamics simulations to explore the stability of graphene nanostructures,i.e.,carbon nanoclusters and graphene nanoribbons,on semi-molten Cu substrates.

Bioinformatic analysis of the ssc-miR-146b upstream promoter region

Sus Scrofa microRNA-146b-5p(ssc-miR-146b) was found to be one of differentially expressional microRNAs(miRNA) in our previous study. Not only it is highly expressed but also it maintains the largest up-regulated differences on the expressional level at different time points in the small intestinal mucosa of weaned piglets. To further explore the regulation mechanism of microRNA-146b-5 p(miR-146b)during the stressful progress in weaned piglets, the present study predicted the functions of the ssc-miR-146b upstream promoter region using biological analysis. The analytical results showed that ssc-miR-146b is an intergenic miRNA. The length of the promoter region of ssc-miR-146b was predicted to be2,249 bp using the Ensemble database. The length of the CpG island in the ssc-miR-146b promoter region was found to be 167 bp and it was located from 464 to 630 bp. Twenty six binding sites of 9 transcription factors in the upstream promoter region, including the sites of genes such as Spl, AP-1, MyoD, GATA etc,were discovered using different kinds of analytical software. The predictions of the CpG island and transcription factor binding sites provided significant information for further studying the transcriptional regulation mechanism of ssc-miR-146b on the small intestinal injury due to weaning stress.

Assessment and improvement of Noah-MP for simulating water and heat exchange over alpine grassland in growing season

Alpine grassland is the main ecosystem of the Tibetan Plateau(TP),thus accurate simulation of water and heat exchange in the grassland will significantly enhance the understanding of the land-atmosphere interaction process on the TP.In this study,we assessed and improved the ensemble numerical simulations of the community Noah land surface model with multiparameterization options(Noah-MP)by using observations collected from four alpine grassland observation sites.The four observation sites belong to the upper Heihe River Basin Integrated Observatory Network located in the northeastern part of the TP.First,an ensemble of 1008 numerical simulation experiments,based on multiparameterization options of seven physical processes/variables in the Noah-MP,was carried out for the vegetation growing season.The Taylor skill score was then used to assess the model performance and select the optimal combination of parameterization options for a more exact simulation of the water and heat exchange in alpine grassland.The accuracy of Noah-MP simulation was further improved by introducing new parameterizations of thermal roughness length,soil hydraulic properties,and vertical root distribution.It was found that:(1)Simulation of water and heat exchange over alpine grassland in the growing season was mainly affected by the parameterizations of dynamic vegetation,canopy stomatal resistance,runoff and groundwater dynamics,and surface exchange coefficient for heat transfer.Selection of different parameterization options for these four physical processes/variables led to large differences in the simulation of water and heat fluxes.(2)The optimal combination of parameterization options selected in the current Noah-MP framework suffered from significant overestimation of sensible heat flux(H)and underestimation of soil moisture(θ)at all observation sites.(3)The overestimation of H was significantly improved by introducing a new parameterization of thermal roughness length.Furthermore,the underestimation ofθwas resolved by introducing a new parameterization of soil hydraulic properties that considered the organic matter effect and a new vertical distribution function for the vegetation root system.The results of this study provide an important reference for further improving the simulation of water and heat exchange by using the land surface model in alpine grassland.

Electrospun Cu-doped In_(2)O_(3) hollow nanofibers with enhanced H2S gas sensing performance

One-dimensional nanofibers can be transformed into hollow structures with larger specific surface area, which contributes to the enhancement of gas adsorption. We firstly fabricated Cu-doped In_(2)O_(3) (Cu-In_(2)O_(3)) hollow nanofibers by electrospinning and calcination for detecting H2S. The experimental results show that the Cu doping concentration besides the operating temperature, gas concentration, and relative humidity can greatly affect the H2S sensing performance of the In_(2)O_(3)-based sensors. In particular, the responses of 6%Cu-In_(2)O_(3) hollow nanofibers are 350.7 and 4201.5 to 50 and 100 ppm H2S at 250 ℃, which are over 20 and 140 times higher than those of pristine In_(2)O_(3) hollow nanofibers, respectively. Moreover, the corresponding sensor exhibits excellent selectivity and good reproducibility towards H2S, and the response of 6%Cu-In_(2)O_(3) is still 1.5 to 1 ppm H2S. Finally, the gas sensing mechanism of Cu-In_(2)O_(3) hollow nanofibers is thoroughly discussed, along with the assistance of first-principles calculations. Both the formation of hollow structure and Cu doping contribute to provide more active sites, and meanwhile a little CuO can form p–n heterojunctions with In_(2)O_(3) and react with H2S, resulting in significant improvement of gas sensing performance. The Cu-In_(2)O_(3) hollow nanofibers can be tailored for practical application to selectively detect H2S at lower concentrations.

The impact of ESG on financial performance:a revisit with a regression discontinuity approach

This study revisits the question of“whether firms are doing well by doing good?”.We examine shareholders-sponsored corporate socially responsible(CSR)proposals related to Environmental,Social,and Governance(ESG)that are voted to pass or fail by a small margin.The adoption of those“close call”proposals is regarded as equivalent to a random assignment of CSR policies and,therefore,provides a quasi-experimental setting to capture the causal influence of CSR on firm performance.We apply the regression discontinuity design(RDD)and find that CSR proposals’passage leads to a significant positive abnormal return on the voting day.The results are robust with both parametric and nonparametric approaches of RDD and different polynomial orders.However,we fail to identify a significant change in financial performance in the long-term.One possible reason is that passing a CSR proposal could be symbolic,rather than substantial.