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201.
HE Min-Hua ZHANG Duan-Ming PAN Gui-Jun YIN Yah-Ping CHEN Zhi-Yuan 《理论物理通讯》2008,50(12):1351-1354
Through using the methods of finite-size effect and short time dynamic scaling, we study the critical behavior of parasitic disease spreading process in a diffusive population mediated by a static vector environment. Through comprehensive analysis of parasitic disease spreading we find that this model presents a dynamical phase transition from disease-free state to endemic state with a finite population density. We determine the critical population density, above which the system reaches an epidemic spreading stationary state. We also perform a scaling analysis to determine the order parameter and critical relaxation exponents. The results show that the model does not belong to the usual directed percolation universality class and is compatible with the class of directed percolation with diffusive and conserved fields. 相似文献
202.
Diego Fontana de Andrade Louise Jank Vitor Breda Rego Roberto Minozzo Marcus Vinícius Burgel Sfoggia Álvaro Bavaresco Fabiano Barreto 《Biomedical chromatography : BMC》2020,34(9):e4873
Saponins from Quillaja saponaria have been commonly used as immunomodulatory adjuvants in foot-and-mouth disease vaccines (FMDVs). However, due to the lack of consensus over the possible exacerbation of local inflammatory responses in cattle and its economic impacts, their use has been discouraged by Brazilian authorities. A qualitative method intended to determine the presence of saponins from Q. saponaria bark extracts in FMDVs was developed and validated. Instrumental analysis was performed using an liquid chromatography (LC) coupled to a quadrupole–time-of-flight–mass spectrometry (TOF-MS) system. The method was validated according to the International Conference on Harmonization Harmonized Tripartite Guideline Q2 (R1) and Brazilian Ministry of Agriculture, Livestock and Food Supply Analytical Quality Assurance Guidelines. Validation parameters were determined and considered suitable to the established criteria. The validated method has been applied in routine analysis in the National Agricultural Laboratory at Rio Grande do Sul (LANAGRO-RS). All results obtained were in agreement with the vaccine's composition described by the manufacturer. The method is easy and adequate for analysis in routine laboratories. To the best of the authors' knowledge, this is the first report of a method which intends to investigate the presence of saponins from Q. saponaria bark extracts in veterinary vaccines. 相似文献
203.
Benzyl protecting protocol was first employed in two routes for the concise synthesis of dopexamine dihydrochloride.This protecting group could be cleanly removed under mild condition and no unacceptable ion was brought to the final product.The total yield of route I was 43.8% from phenylacetic acid,while it was 54.1% of route II from 2-(3,4-bis(benzyloxy)phenyl)acetic acid.The titration purity of the final product was more than 99.5%,while any single or total impurities met the known standard of the drug by HPLC analysis.The measured residual palladium met an acceptable limit(<1 ppm) as an API for injection. 相似文献
204.
Wei Ouyang Prof. Jongyoon Han 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):11074-11081
Nucleic acid amplification tests (NAATs)integrated on a chip hold great promise for point-of-care diagnostics. Currently, nucleic acid (NA) purification remains time-consuming and labor-intensive, and it takes extensive efforts to optimize the amplification chemistry. Using selective electrokinetic concentration, we report one-step, liquid-phase NA purification that is simpler and faster than conventional solid-phase extraction. By further re-concentrating NAs and performing polymerase chain reaction (PCR) in a microfluidic chamber, our platform suppresses non-specific amplification caused by non-optimal PCR designs. We achieved the detection of 5 copies of M. tuberculosis genomic DNA (equaling 0.3 cell) in real biofluids using both optimized and non-optimal PCR designs, which is 10- and 1000-fold fewer than those of the standard bench-top method, respectively. By simplifying the workflow and shortening the development cycle of NAATs, our platform may find use in point-of-care diagnosis. 相似文献
205.
Dr. Jun Ma Chao Ma Dr. Jingjing Li Dr. Yao Sun Prof. Fangfu Ye Prof. Kai Liu Prof. Hongjie Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(53):12101-12110
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases and characterized by cognitive and memory impairments. Emerging evidence suggests that the extracellular matrix (ECM) in the brain plays an important role in the etiology of AD. It has been detected that the levels of ECM proteins have changed in the brains of AD patients and animal models. Some ECM components, for example, elastin and heparan sulfate proteoglycans, are considered to promote the upregulation of extracellular amyloid-beta (Aβ) proteins. In addition, collagen VI and laminin are shown to have interactions with Aβ peptides, which might lead to the clearance of those peptides. Thus, ECM proteins are involved in both amyloidosis and neuroprotection in the AD process. However, the molecular mechanism of neuronal ECM proteins on the pathophysiology of AD remains elusive. More investigation of ECM proteins with AD pathogenesis is needed, and this may lead to novel therapeutic strategies and biomarkers for AD. 相似文献
206.
207.
Jia-Kuo Liu Wei Gu Xiao-Rui Cheng Jun-Ping Cheng Wen-Xia Zhou Ai-Hua Nie 《中国化学快报》2015,26(10):1327-1330
Based on the lead compound 1 reported in literature, a series of novel BACE1 inhibitors were designed and synthesized, among which compound 11 exhibited a 14-fold improvement in potency over the lead compound 1. This represents a good lead for the discovery of more promising BACE1 inhibitors for the potential treatment of AD. 相似文献
208.
We investigate a model consisting of a predator population and both susceptible and infected prey populations. The predator can feed on either prey species but instead of choosing individuals at random the predator feeds preferentially on the most abundant prey species. More specifically we assume that the likelihood of a predator catching a susceptible prey or an infected prey is proportional to the numbers of these two different types of prey species. This phenomenon, involving changing preference from susceptible to infected prey, is called switching. Mukhopadhyay studied a switching model and proposed that the interaction of predators with infected prey is beneficial for the growth of the predator. In this model, we assume that the predator will eventually die as a result of eating infected prey. We find a threshold parameter and showed that the disease will be eradicated from the system if . 相似文献
209.
Interaction of PiB‐Derivative Metal Complexes with Beta‐Amyloid Peptides: Selective Recognition of the Aggregated Forms
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Dr. André F. Martins David M. Dias Dr. Jean‐François Morfin Dr. Sara Lacerda Dr. Douglas V. Laurents Dr. Éva Tóth Prof. Carlos F. G. C. Geraldes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5413-5422
Metal complexes are increasingly explored as imaging probes in amyloid peptide related pathologies. We report the first detailed study on the mechanism of interaction between a metal complex and both the monomer and the aggregated form of Aβ1–40 peptide. We have studied lanthanide(III) chelates of two PiB‐derivative ligands (PiB=Pittsburgh compound B), L1 and L2, differing in the length of the spacer between the metal‐complexing DO3A macrocycle (DO3A= 1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid) and the peptide‐recognition PiB moiety. Surface plasmon resonance (SPR) and saturation transfer difference (STD) NMR spectroscopy revealed that they both bind to aggregated Aβ1–40 (KD=67–160 μM ), primarily through the benzothiazole unit. HSQC NMR spectroscopy on the 15N‐labeled, monomer Aβ1–40 peptide indicates nonsignificant interaction with monomeric Aβ. Time‐dependent circular dichroism (CD), dynamic light scattering (DLS), and TEM investigations of the secondary structure and of the aggregation of Aβ1–40 in the presence of increasing amounts of the metal complexes provide coherent data showing that, despite their structural similarity, the two complexes affect Aβ fibril formation distinctly. Whereas GdL1, at higher concentrations, stabilizes β‐sheets, GdL2 prevents aggregation by promoting α‐helical structures. These results give insight into the behavior of amyloid‐targeted metal complexes in general and contribute to a more rational design of metal‐based diagnostic and therapeutic agents for amyloid‐ associated pathologies. 相似文献
210.
Ai-hua Zhang Zhi-ming Ma Ling Kong Hong-lei Gao Hui Sun Xiang-qian Wang Jing-bo Yu Ying Han Guang-li Yan Xi-jun Wang 《Biomedical chromatography : BMC》2020,34(2):e4724
Lipid metabolism has a significant function in the central nervous system and Alzheimer's disease (AD) is an age-related senile disease characterized by central nerve degeneration. The pathological development of AD is closely related to lipid metabolism disorders. To reveal the influence of Kai-Xin-San (KXS) on lipid metabolism in APP/PSI transgenic mice and potential therapeutic targets for treating AD, brain tissue samples were collected and analyzed by high-throughput lipidomics based on UPLC–Q/TOF-MS. The collected raw data were processed by multivariate data analysis to discover the potential biomarkers and lipid metabolic profiles. Compared with the control wild-type mouse group, nine potential lipid biomarkers were found in the AD model group, of which seven were up-regulated and two were down-regulated. Orally administrated KXS can reverse the changes in these potential biomarkers. Compared with the model group, a total of six differential metabolites showed a recovery trend and may be potential targets for KXS to treat AD. This study showed that high-throughput lipidomics can be used to discover the perturbed pathways and lipid biomarkers as potential targets to reveal the therapeutic effects of KXS. 相似文献