Users' cognition and information retrieval are faced with great challenges in ubiquitous knowledge environ-ment. The influence of cognitive factors such as personality traits, cognitive style and ability, knowledge structure and ascribed methods on users' information retrieval behaviors was thus analyzed. It was pointed out that different cognitive factors could influence the retrieval, judgment and absorption of its results,users' satisfaction and continuous use in ubiquitous knowledge environment,with suggestions put forward from the aspects of information retrieval education, information service and information users for improving the users ' knowledge system in knowledge assimilating process by working out effective retrieval strategies using the advantages of cognition.

Structural maintenance of chromosomes (SMC), including cohesin, condensin and the SMC5/6 complex, are protein complexes which maintain the higher structure and dynamic stability of chromatin. Such circular complexes, with similar structures, play pivotal roles in chromatid cohesion, chromosomal condensation, DNA replication and repair, as well as gene transcription. Despite extensive research on the functions of the SMCs, our understanding of the SMC5/6 complex has remained limited compared with the other two complexes. This article has reviewed the architecture and crucial physiological roles of the SMCs, and explored the associated phenotypes resulting from mutations of the SMC components such as Cornelia de Lange syndrome (CdLS) and microcephaly, with an aim to provide insights into their functions in eukaryotic cells and implications for human diseases.

OBJECTIVETo investigate the molecular epidemiological characteristics and antibiotic resistance profiles of Vibrio cholerae O139 in Shandong province.

METHODSA total of 13 strains of V. cholerae O139 (9 clinical strains and 4 environmental strains) isolated from cholera epidemics in Shandong province since 1997 were recovered and confirmed with serum agglutination and biochemical reaction. Pulsed-field gel electrophoresis (PFGE) was carried out for molecular subtyping. Virulence genes and drug resistance related genes were detected by PCR. Antibiotic susceptibility tests were performed using micro-broth dilution method.

RESULTSThirteen strains of V. cholerae O139 were differentiated into seven pulsetypes. One clinical strain and two environmental strains isolated from Jining in 2013 were clustered into the pulsetype namely KZGN11O139. CN0077, and an identical PFGE pattern of KZGN11O139. CN0002 was found among three clinical strains from Jinan in 2005, Jining in 2005 and Heze in 2009. Other pulsotypes were unique in China and found only in Shandong province. Because of deletion of ctxAB and tcpI, the PFGE patterns of two strains isolated from Yantai in 2000 and 2004 were different from other 11 strains which harbored ctxAB, tcpA, tcpI, rtxA, hlyA and toxR. All strains contained one or more drug resistance related genes such as intI 1, intI 4 and sxt, and were resistant to two kinds of antibiotics at least. Among the 12 kinds of antibiotics, the resistant ratioes to kamamycin, trimethoprim-sulfamethoxazole, ampicillin and gentamicin were 11/13, 9/13, 7/13 and 7/13, respectively.

CONCLUSIONMolecular subtyping indicates possible epidemiological links among V.cholerae O139 in Shandong province, and almost all strains were toxigenic and drug resistant.

China ; Cholera ; Cholera Toxin ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Epidemics ; Humans ; Molecular Epidemiology ; Polymerase Chain Reaction ; Vibrio cholerae O139 ; Virulence

Colorectal cancer(CRC),the most common malignant tumor of the digestive system with the highest morbidity and mortality worldwide,has received increasing attention for its relationship with the gut microbiota.The gut microbiota interacts with the host cells to regulate various physiological processes,including metabolism and immune responses.Recently,increasing research has revealed that the interaction between the host and gut microbiota plays a significant role in the origin and progression of CRC.In this review,we discuss the specific mechanisms of the gut microbiota involvement in the carcinogenesis,invasion,and metastasis of CRC,as well as its impact on the therapeutic response and prognosis,by describing the gut and intratumoral microbiota associated with CRC.This information serves as a ref-erence for understanding the relationship between gut microbiota and CRC,and provides therapeutic ideas for the development of microbi-ota-based interventions for CRC treatment.

ObjectivesTo analyze the spatial and temporal clustering characteristics and related influencing factors of late diagnosis of HIV/AIDS in Lanzhou， to identify its high-risk areas and time trends in Lanzhou， and to provide a theoretical basis for developing targeted HIV/AIDS prevention and control strategies in Lanzhou. MethodsThe subjects of this study were adult HIV/AIDS cases reported in Lanzhou City between 2011 and 2018. Data used in the study were sourced from the Lanzhou Center for Disease Control and Prevention and the Lanzhou Statistical Yearbook. To analyze the spatial distribution characteristics and influencing factors of the relative risk （RR） of late HIV/AIDS diagnosis， Bayes spatial-temporal model was used. ResultsA total of 1984 new HIV/AIDS cases were reported in Lanzhou from 2011 to 2018， with an mean age of 37.51 years and predominantly male （91.8%）. The number of late diagnosis cases was 982， with an mean age of 39.67 years and a predominance of males （91.8%）. Late diagnosis was more common in older individuals and women with HIV/AIDS. Chengguan District （51.1%）， Anning District （50.3%） and Yuzhong County （51.9%） had an above-average proportion of late diagnosis of HIV/AIDS. The proportion of late diagnosis cases in Lanzhou showed a fluctuating upward trend from 2011 to 2018. The results of Bayes spatial-temporal model showed that the risk of late HIV/AIDS diagnosis in Lanzhou had fluctuated from 2011 to 2015， and then increased rapidly after 2015 ［RR （95% credibility interval， 95%CI） increased from 1.01 （0.84， 1.23） to 1.11 （0.77， 1.97）］； the trends of risk of late diagnosis in Honggu district and three counties were similar to the overall trend in Lanzhou city， while the risk of late diagnosis in Chengguan District and Qilihe District showed a decreasing trend. The regions with the RR for late diagnosis greater than 1 included Yongdeng County （RR=1.07， 95% CI： 0.55， 1.96）， Xigu District （RR=1.04， 95% CI： 0.67， 1.49）， Chengguan District （RR=2.41， 95% CI： 0.85， 6.16）， and Qilihe District （RR=2.03， 95% CI： 1.10， 3.27）. Besides， the heatmap analysis showed that Chengguan District and Qilihe District were the hot spots. The influencing factors analysis showed that the higher GDP per capita （RR=0.65， 95% CI： 0.35， 0.90） and the larger proportion of males with HIV/AIDS cases （RR=0.53， 95% CI： 0.19， 0.92） could lead to the lower the relative risk of late HIV/AIDS diagnosis. However， the higher the population density （RR=1.35， 95% CI： 1.01， 1.81） caused the higher the risk of late diagnosis. ConclusionOur study shows the risk of late diagnosis of HIV/AIDS in Lanzhou was on the rise， and there are significant regional differences. GDP per capita， the proportion of males in HIV/AIDS cases and population density are influencing factors in the late diagnosis of HIV/AIDS. Therefore， for regions with a high risk of late diagnosis or related risk factors， targeted HIV screening and prevention services should be given priority in order to reduce the proportion and risk of late diagnosis of HIV/AIDS.

Arnebiae Radix is used widely in TCM external treatment. It has obvious curative effect on skin diseases， wound infection and local inflammation， and is used to treat water and fire burns， skin ulcers， eczema， psoriasis， vitiligo and atopic dermatitis， etc. The clinical and commercial preparations mainly include ointment， liniment and suppository. Modern research has proved that microcapsules， nano-micelles， nanofiber membranes， nanogels and other novel nanoformulations can significantly improve the stability of drug-effective substances， improve local drug concentration and targeting， and perform sound drug release properties in vitro. This paper reviews the variety and application of Arnebiae Radix traditional preparations for external use and the research progress of novel nanoformulations of Arnebiae Radix， from which we prospect to provide some valuable references for the future application and development of Arnebiae Radix external preparations.