843 research outputs found

    Advanced modification of drug nanocrystals by using novel fabrication and downstream approaches for tailor-made drug delivery

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    Drug nanosuspensions/nanocrystals have been recognized as one useful and successful approach for drug delivery. Drug nanocrystals could be further decorated to possess extended functions (such as controlled release) and designed for special in vivo applications (such as drug tracking), which make best use of the advantages of drug nanocrystals. A lot of novel and advanced size reduction methods have been invented recently for special drug deliveries. In addition, some novel downstream processes have been combined with nanosuspensions, which have highly broadened its application areas (such as targeting) besides traditional routes. A large number of recent research publication regarding as nanocrystals focuses on above mentioned aspects, which have widely attracted attention. This review will focus on the recent development of nanocrystals and give an overview of regarding modification of nanocrystal by some new approaches for tailor-made drug delivery

    A mechanism of glucose tolerance and stimulation of GH1 β-glucosidases

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    β-Glucosidases are enzymes that hydrolyze β-glycosidic bonds to release non-reducing terminal glucosyl residues from glycosides and oligosaccharides, and thus have significant application potential in industries. However, most β-glucosidases are feedback inhibited by the glucose product, which restricts their application. Remarkably, some β-glucosidases of the glycoside hydrolase (GH) 1 family are tolerant to or even stimulated by glucose. Elucidation of the mechanisms of glucose tolerance and stimulation of the GH1 β-glucosidases will be crucial to improve their application through enzyme engineering. In this study, by comparing the primary and tertiary structures of two GH1 β-glucosidases with distinct glucose dependence, some putative glucose-dependence relevant sites were mutated to investigate their exact roles. Both biochemical and structural characterization of the mutants suggested that some sites at the entrance and middle of the substrate channel regulate the effects of glucose, and the relative binding affinity/preference of these sites to glucose modulates the glucose dependence. A mechanism was therefore proposed to interpret the glucose dependence of GH1 β-glucosidases. This research provides fresh insight into our current understanding of the properties and mechanisms of GH1 β-glycosidases and related enzymes that modulate their activity via feedback control mechanism

    Strong aftershocks traffic light system: A case study of the 8 January 2022 MS6.9 Menyuan earthquake, Qinghai Province, China

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    Strong aftershocks, especially the disaster-causing M≥5.0 kind, are a key concern for mitigation of seismic risks because they often lead to superimposed earthquake damage. However, the real-time forecasting results of the traditional probability prediction models based on statistics are usually far from accurate and therefore unsatisfactory. Borrowing an idea from the foreshock traffic light system (FTLS), which is based on observations of decreasing b-values or increasing differential stress just before a strong aftershock, we constructed a strong aftershock traffic light system (SATLS) that uses data-driven technology to improve the reliability of time sequence b-value calculations, and analyzed the b-value variations of strong aftershocks in the China continent. We applied this system to the MS6.9 Menyuan earthquake occurred on 8 January 2022. The earthquake occurrence rates before the largest aftershock (MS5.2) forecast by the Omi-R-J model were too low, although the model could accurately forecast aftershock rates for each magnitude interval in most time-periods. However, reliable b-values can be calculated using the time-sequence b-value data-driven (TbDD) method, and the results showed that the b-values continued declining from 1.3 days before the MS5.2 aftershock and gradually recovered afterward. This would suggest that the stress evolution in the focal area can provide data for deciding when to post risk alerts of strong aftershocks. In the process of building the SATLS, we studied thirty-four M≥6.0 intraplate earthquake sequences in the China continent and concluded that the differences between the b-values of the aftershock sequences and of the background events, △b = bafter - bbg = ±0.1, could be used as thresholds to determine whether M≥5.0 aftershocks would occur. The △b value obtained using the events before the MS5.2 aftershock of the MS6.9 Menyuan sequence was about -0.04, which would have caused the SATLS to declare a yellow alert, but there would have been some gap expected before a red alert was triggered by the b-value difference derived from the events associated with this strong aftershock. To accurately forecast a strong aftershock of M≥5.0, a deeper understanding of the true b-value and a detailed description of the stress evolution state in the source area is necessary

    Importance-Aware Image Segmentation-based Semantic Communication for Autonomous Driving

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    This article studies the problem of image segmentation-based semantic communication in autonomous driving. In real traffic scenes, detecting the key objects (e.g., vehicles, pedestrians and obstacles) is more crucial than that of other objects to guarantee driving safety. Therefore, we propose a vehicular image segmentation-oriented semantic communication system, termed VIS-SemCom, where image segmentation features of important objects are transmitted to reduce transmission redundancy. First, to accurately extract image semantics, we develop a semantic codec based on Swin Transformer architecture, which expands the perceptual field thus improving the segmentation accuracy. Next, we propose a multi-scale semantic extraction scheme via assigning the number of Swin Transformer blocks for diverse resolution features, thus highlighting the important objects' accuracy. Furthermore, the importance-aware loss is invoked to emphasize the important objects, and an online hard sample mining (OHEM) strategy is proposed to handle small sample issues in the dataset. Experimental results demonstrate that the proposed VIS-SemCom can achieve a coding gain of nearly 6 dB with a 60% mean intersection over union (mIoU), reduce the transmitted data amount by up to 70% with a 60% mIoU, and improve the segmentation intersection over union (IoU) of important objects by 4%, compared to traditional transmission scheme.Comment: 10 pages, 8 figure

    A high-energy liquid-jet hammer with specially designed backward stroke end buffer structure

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    A high-energy liquid-jet hammer with specially designed backward stroke end buffer structure was investigated computationally. Computational Fluid Dynamics (CFD) with the technique of dynamic and sliding meshes method was employed in this study. Results indicated that each of the geometric parameter of the buffer structure had a significant effect on the backward impacting energy of the impact body and brought a maximum of 49.8 % of backward impacting energy reduction. Experimental tests based on the non-contact measuring method were conducted to verify the simulation results, by which the accuracy and reliability of this CFD simulation method was proved. In addition, the high-energy liquid-jet hammer worked well with the optimal parameters of the buffer structure in bench testing and reached high penetration rate in a drilled borehole

    Impact of Phenolic Constituents and Antioxidant Activities of Acer truncatum Leaves and Flowers upon Different Thermal Treatments

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    In order to promote the development and application of Acer truncatum leaves and flowers in the food area, in this study, the dynamic changes of their phenolic composition and antioxidant activity were investigated under steam, microwave, and baking treatments, meanwhile, three time periods were further selected to determine the contents of total phenols and major phenolic compounds, together with the variations of antioxidant abilities of samples before and after the three treatments, and those data were finally analyzed through principal components and correlation analyses. The results showed that baking significantly increased the total phenol content from 75.80±3.54 mg GAE/g to 82.55±2.54~87.78±1.53 mg GAE/g in Acer truncatum leaves (P<0.05), while there was no significant difference of the total phenol content among untreated leaves and flowers and those samples under other treatments. Among phenolic compounds in leaves, gallates including gallic acid, ethyl gallate, and 1,2,3,4,6-penta-O-galloyl-β-d-glucose increased in varying degrees under all three treatments, and 1,2,3,4,6-penta-O-galloyl-β-d-glucose increased 1.88-fold under 15 min baking. Nevertheless, prolong microwave or baking treatment led to the reduction of increasing rate of gallates content. The above change pattern of gallates also existed in flowers, but in a relatively gentle mode. The result of antioxidant assays demonstrated that the oxygen radical absorbance capacity values significantly increased in Acer truncatum leaves and flowers after most treatments, and the highest increase in leaves and flowers were 1.49 and 1.21 times, respectively. Principal components and correlation analysis revealed that the variation of the gallates was significantly correlated with the change of the total phenol content, and different phenolic compounds in leaves and flowers had different degrees of contribution to the overall antioxidant activity. The above results indicated that thermal treatment method and time period all significantly affected the phenolic composition and antioxidant activities of Acer truncatum leaves and flowers (P<0.05). Therefore, a proper selection of treatment condition was vital for the improvement of their biological activity and commodity value. Among which, FM10 (microwave treatment for 10 min) led to the enhancement of antioxidant activity of both leaves and flowers. Above all, the present research provided a theoretical basis for the processing and further study of Acer truncatum leaves and flowers as food resources

    Convergence and Disparities in Higher Education Fiscal Expenditures in China: A Regional Perspective

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    This research investigates the disparities and convergence in higher education fiscal expenditures across different regions in China. The study utilises Gini coefficient analysis and σ-convergence/β-convergence tests to quantify the extent of disparities and explore convergence trends over a twelve-year investigation period (2007–2018). The results shed light on the imbalances in resource allocation and provide valuable insights into the efforts required to achieve a more equitable distribution of fiscal resources for higher education. The findings reveal significant disparities in higher education fiscal expenditures between the Eastern, Central, Western, and Northeastern regions, with the Eastern region exhibiting the largest gap compared to others. Remarkably, the disparity between the Eastern and Central regions is even greater than that between the Eastern and Western regions, emphasising the need for targeted interventions to address regional imbalances. Over the study period, the gap between the Eastern and Central regions remained consistently higher than other regional disparities. Moreover, the research shows a general trend towards narrowing regional fiscal expenditure disparities, with the most pronounced convergence observed between the Central and Northeastern regions. The Western region exhibits slightly larger disparities than the Central and Northeastern regions, possibly attributed to greater fiscal policy support and lower student enrollments. Nevertheless, the fiscal expenditure gap between the Western and Central regions has shown a trend towards reduction. The study also explores absolute and conditional β-convergence, revealing notable convergence patterns in the Eastern and Central regions. However, the Western and Northeastern regions exhibit varying degrees of convergence, indicating the necessity for region-specific convergence mechanisms. To achieve a balanced allocation of financial resources for higher education across regions, the study recommends targeted fiscal policies, additional funding, and improved transparency and accountability. Policymakers should focus on enhancing convergence mechanisms to ensure a more equitable distribution of resources and foster the sustainable development of higher education throughout the country. While this research provides valuable insights, it is essential to consider other potential factors influencing fiscal expenditure disparities, such as policy orientation, economic disparities, and demographic structures, for a more comprehensive understanding. Future research may benefit from qualitative investigations to further explore the complexities of higher education fiscal expenditure imbalances and identify effective policy interventions

    Effectiveness of Higher Education Financing: DEA and SFA Modelling

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    The article aims to assess the effectiveness of financial expenditures in higher education for 31 provinces in China, namely overall, technical and scale efficiency, and to determine whether the returns to scale are increasing or decreasing for each province. The main method used is the three-stage DEA analysis / Data Envelopment Analysis, and software DEAP2.1 and Frontier 4.1 are used for modelling. Financial expenditures on higher education form an input parameter in the DEA model. The output parameters (determining the efficiency of higher education) are the number of students, the number of full-time teachers and the new value added to fixed assets in higher education institutions. The modelling was carried out for 2008-2013 and 2014-2018 (the COVID-19 pandemic is not considered to avoid uncommon trends and unpredictable disturbances in the model). A comparison of the analysis results for these periods allowed the identification of new trends and patterns. The study takes into account three main groups of parameters: 1) endogenous (inefficiency of internal management processes); 2) exogenous (gross regional product per capita of each province in China; the extent of university clustering, which is determined by political and market decisions and does not depend on educational institutions; and the degree of fiscal decentralisation, which is estimated in the article as the ratio of local and state budget expenditures per capita, taking into account the distribution of total budget expenditures for each district and the total population of the respective territory); 3) random disturbances. At the first stage of the study, a BCC model focused on inputs (to assess the technical efficiency of financial expenditures on higher education in different provinces) was built. It does not consider exogenous factors and random disturbances. In the second stage, SFA (stochastic frontier analysis) was applied to account for the impact of all three groups of factors (endogenous, exogenous and statistical noise) on the efficiency of financial expenditures in higher education for each province in China. In the third stage, the adjusted and standardised input and output parameters are incorporated into the BCC models, and the actual value of efficiency caused by exogenous parameters and the influence of random factors is determined. A comparison of the results of each modelling stage for each stage in the study and each province in China allowed the establishment of how the influence of the determinants of higher education financing efficiency changed in chronological and spatial contexts

    Habitat Elevation Shapes Microbial Community Composition and Alter the Metabolic Functions in Wild Sable (Martes zibellina) Guts

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    In recent decades, wild sable (Carnivora Mustelidae Martes zibellina) habitats, which are often natural forests, have been squeezed by anthropogenic disturbances such as clear-cutting, tilling and grazing. Sables tend to live in sloped areas with relatively harsh conditions. Here, we determine effects of environmental factors on wild sable gut microbial communities between high and low altitude habitats using Illumina Miseq sequencing of bacterial 16S rRNA genes. Our results showed that despite wild sable gut microbial community diversity being resilient to many environmental factors, community composition was sensitive to altitude. Wild sable gut microbial communities were dominated by Firmicutes (relative abundance 38.23%), followed by Actinobacteria (30.29%), and Proteobacteria (28.15%). Altitude was negatively correlated with the abundance of Firmicutes, suggesting sable likely consume more vegetarian food in lower habitats where plant diversity, temperature and vegetation coverage were greater. In addition, our functional genes prediction and qPCR results demonstrated that energy/fat processing microorganisms and functional genes are enriched with increasing altitude, which likely enhanced metabolic functions and supported wild sables to survive in elevated habitats. Overall, our results improve the knowledge of the ecological impact of habitat change, providing insights into wild animal protection at the mountain area with hash climate conditions
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