含醚键双二氮杂萘酮结构聚芳醚腈砜的合成与性能

文中以含醚键双二氮杂萘酮结构化合物4,4’-双(氧基(1,4-苯撑))-双二氮杂萘-1(2H)酮-二苯醚(OBDHPZ)为类双酚单体,与4,4’-二氟二苯砜(DFS)和2,6’-二氟苯腈(DFBN)进行高温溶液缩聚反应,通过调节聚合物分子主链中砜基和氰基等的含量,合成了一系列不同腈砜比的含醚键双二氮杂萘酮联苯结构聚芳醚腈砜树脂(PBPENS),其N-甲基吡咯烷酮(NMP)溶液在25℃的特性黏度为0.63~0.90 dL/g。通过红外光谱、核磁共振氢谱和广角X射线衍射仪表征了所合成聚芳醚腈砜的结构;通过差示扫描量热仪和热失重分析仪分析了该类聚芳醚腈砜的热性能,聚合物的玻璃化转变温度(Tg)在322~325℃,5%热失重温度(Td5%)在485~500℃。该类聚合物在常温时可溶解于NMP、N,N-二甲基乙酰胺(DMAc)、氯仿等极性非质子有机溶剂;采用溶液浇筑法制备了含醚键双二氮杂萘酮结构聚芳醚腈砜薄膜,薄膜的拉伸强度可以达到56~65 MPa。

Genome-wide identification and analysis of the DREB genes and their expression profiles under abiotic stresses in Chinese jujube(Ziziphus jujuba Mill.)

CBF/DREB proteins play a critical role in abiotic stress-mediated gene expression and represent attractive regulons for plant breeding programs.However,no study has been conducted for CBF/DREB protein-related genes in jujube(Ziziphus jujuba Mill.).In this study,twenty-five ZjDREB genes were identified and annotated from the jujube(Z.jujuba‘Dongzao’)genome.Detailed analysis,including gene classification,annotation,phylogenetic evaluation,conserved motif determination and expression profiling were performed on all genes.Phylogenetic analysis showed that ZjDREB proteins were divided into five subgroups(A1–A5),but lacking a subgroup A6 corresponding to AtDREBs.The ZjDREB genes were distributed in nine of twelve chromosomes in the genome.Additionally,the expression patterns of the DREB genes under different abiotic stresses were investigated using q RT-PCR.Nineteen ZjDREB genes were down-regulated under low temperature,in contrast six ZjDREB genes(01,03,05,11,23 and 24)were up-regulated.Under drought,salinity and high temperature conditions,expression of ZjDREB03,09,10,14,15,17 and 20 genes were induced and showed similar expression patterns,suggesting that various stress conditions share common elements in the signaling pathway.The results suggest that the family of DREB genes play an important role in abiotic stresses in jujube,and provide a foundation for further functional studies of this important class of transcriptional regulators.

Bone density, microarchitecture and stiffness in Caucasian and Caribbean Hispanic postmenopausal American women

Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aimed to compare Caucasian and Caribbean Hispanic postmenopausal American women with respect to these characteristics. Thirty-three Caribbean Hispanics were age-matched to thirty-three Caucasian postmenopausal women. At the lumbar spine, the Hispanic women had significantly lower areal bone mineral density （aBMD）. At the radius by high-resolution peripheral quantitative computed tomography （HR-pQCT）, there were minimal differences between Hispanic and Caucasian women. At the tibia, Hispanic women had lower trabecular volumetric bone density and trabecular number, and higher trabecular separation. Individual trabecula segmentation （ITS） analyses indicated that at the tibia, Hispanic women not only had significantly lower bone volume fraction, but also had significantly lower rod bone volume fraction, plate trabecular number, rod trabecular number and lower plate-plate, plate-rod and rod-rod junction densities compared to Caucasian women. The differences in bone quantity and quality contributed to lower whole bone stiffness at the radius, and both whole bone and trabecular bone stiffness at the tibia in Hispanic women. In conclusion, Hispanic women had poorer bone mechanical and microarchitectural properties than Caucasian women, especially at the load-bearing distal tibia.

Optimization of the Structural Parameters of a Plastic Centrifugal Pump in the Framework of a Flow Field Analysis

In order to determine the optimal structural parameters of a plastic centrifugal pump in the framework of an orthogonal-experiment approach,a numerical study of the related flow field has been performed using CFX.The thickness S,outlet angleβ2,inlet angleβ1,wrap angle,and inlet diameter D1 of the splitter blades have been considered as the variable factors,using the shaft power and efficiency of the pump as evaluation indices.Through a parametric analysis,the relative importance of the influence of each structural parameter on each evaluation index has been obtained,leading to the following combinations:β119°,β235°,S 2 mm,wrap angle 154°,and D185 mm(corresponding to the maximum efficiency of 75.48%);β119°,β220°,S 6 mm,wrap angle 158°,and D181 mm(corresponding to the minimum shaft power of 75.48%).Moreover,the grey correlation method has been applied to re-optimize the shaft power and efficiency of the pump,leading to the following optimal combination:β119°,β215°,S 4 mm,D181 mm,and wrap angle 152°(corresponding to the maximum efficiency of 71.81%and minimum shaft power of 2.187 kW).

Inhaled multilevel size-tunable,charge-reversible and mucus-traversing composite microspheres as trojan horse:Enhancing lung deposition and tumor penetration

Dry powder inhalation represents a promising approach for the treatment of lung cancer,offering several advantages such as enhanced targeting,improved bioavailability,and reduced toxicity.However,traditional dry powder formulations suffer from limitations,notably low pulmonary delivery efficiency and inadequate penetration into tumor tissues,thereby limiting their therapeutic efficacy.In response to these challenges,we have developed an innovative trojan horse strategy,harnessing an inhalable nanoparticlein-microsphere system characterized by tunable size,reversible charge,and mucus-penetrating capabilities.The inhalable nanoparticle-in-microsphere system exhibit stable structural properties,excellent environmental responsiveness and high biocompatibility.More importantly,the therapeutic effect of MTX@PAMAM@HA@Gel(MPHG)was demonstrated in vitro and in vivo.This system offers improved pulmonary delivery efficiency,enhanced drug retention within tumor tissues,and effective penetration,thus representing a promising strategy in lung cancer treatment.

Evaluating the flavor and divergent bacterial communities in corn-based zha-chili

Zha-chili is a naturally fermented traditional food from central southern China.Corn-based zha-chili is one of the most popular varieties with a special flavor.To investigate its distinct microbiome,corn-based zha-chili samples were collected and investigated using both high-throughput sequencing and culture-dependent method.Subsequently,E-nose and E-tongue sensors were used to evaluate the overall sensory profile.We found that the bacterial communities present in zha-chili samples from the two regions were significantly different(P<0.05).Companilactobacillus,Lactiplantibacillus,and Corynebacterium were found to be the dominant genera common to samples from both regions.Among these,lactic acid bacteria were the most dominant.Biomarker genera were Ligilactobacillus,Lactobacillus,and Levilactobacillus(Huaihua)and Pantoea,Lactiplantibacillus,and Weissella(Songtao).Using culture-dependent methods,the most dominant genus Companilactobacillus was found to comprise Companilactobacillus alimentarius and Companilactobacillus futsaii.The sensory profile was also characterized.This indicated that zha-chili from the two regions could be discriminated by sourness and aftertaste-B(E-taste),and W1C,W3C,W5C,W1S,W2S,W5S,and W2W(E-nose).Correlation analysis suggested that the dominant genera might not affect the aroma quality of corn-based zha-chili,whereas they were related to taste quality.Levilactobacillus and Ligilactobacillus were positively correlated with the characteristic taste indices and negatively correlated with the off-flavor indices.Another dominant genus,Kocuria was positively correlated with umami and richness(P<0.05).Our results could provide a basis for supporting zha-chili production and help the isolation of appropriate lactic acid bacteria from corn-based zha-chili.

A Lamellar Ceria Structure with Encapsulated Platinum Nanoparticles

A novel lamellar feather-like CeO_(2) structure has been fabricated by using a triblock copolymer as the structure-directing agent.This material was characterized in detail by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,and BET surface area measurements.Compared with conventional spherical shaped ceria prepared by ammonia gelation,the ceria feathers have superior ability to support nanosized platinum particles due to their special structure.The“skeletons”of ceria feathers can serve as an ideal host matrix to anchor the platinum particles.Furthermore,the inter-crossing pattern of the“skeletons”also acts as a partition to separate platinum particles,allowing the Pt nanoparticles(average diameter~6 nm)to be highly dispersed in the structure.The Pt/feather-like CeO_(2) catalyst exhibits high activity in the water gas shift reaction.