Application of oblique photogrammetry technique in geological hazard identification and decision management

With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dangerous mountainous areas under the premise of ensuring the safety of personnel while restoring the real geographic information as much as possible. However, geological disaster areas are often accompanied by many adverse factors such as cliffs and dense vegetation. Based on this, the paper introduced the flight line design of oblique photogrammetry, analyzed the multi-platform data fusion processing, studied the multi-period data dynamic evaluation technology and proposed the application methods of data acquisition, early warning, disaster assessment and decision management suitable for geological disaster identification through the analysis of actual cases, which will help geologists to plan and control geological work more scientifically and rationally, improve work efficiency and reduce the potential personnel safety hazards in the process of geological survey, to offer technical support to the application of oblique photogrammetry in geological disaster identification and decision making and provide the scientific basis for personal and property safety protection and later-stage geological disaster management in disaster areas.

A survey of the information needs of visually impaired library users

Purpose:The research aims to investigate the information needs of visually impaired library users in China in order to increase our understanding of these users and help the Chinese public libraries improve their services for them.Design/methodology/approach:A questionnaire survey was used to study the library users’ information needs.Eleven large public libraries in different areas of China,which were pioneers in implementing services for visually impaired people,were chosen to conduct the survey.Data analysis was based on 97 valid questionnaires retrieved.Findings:Radio and television were still the preferred sources of information for visually impaired users.In information seeking,they had a strong preference for obtaining information in the most convenient way,and accessing a vast amount of information,which was updated quickly.They paid more attention to the information closely related to their work and life.Their purposes of seeking information were mainly for learning,relaxation and intercommunication.Visually impaired users felt some barriers in their access to library services such as a lack of time or a sighted companion who can come along for the trip to the library.Moreover,it was difficult for them to use the Internet to search for information,because many websites do not support the auxiliary software designed especially for visually impaired users or the websites offer only a paid subscriber service.Research limitations:A majority of the respondents were young and middle-aged people and engaged in work.The sample size needs to be enlarged,and different groups of users such as old people and students should be included to yield more useful results.Practical implications:The survey results provide insights into the information needs of the Chinese visually impaired library users.Meanwhile,the research can serve as a reference source for the future studies of the service for visually impaired library users.Originality/value:So far,few studies were conducted to investigate the information needs of visually impaired library users in China.

A combined virtual impactor and field-effect transistor microsystem for particulate matter separation and detection

Ambient suspended particulate matter(PM)(primarily with particle diameter 2.5m or less,i.e.,PM2.5)can adversely affect ecosystems and human health.Currently,optical particle sensors based on light scattering dominate the portable PM sensing market.However,the light scattering method has poor adaptability to different-sized PM and adverse environmental conditions.Here,we design and develop a portable PM sensing microsystem that consists of a micromachined virtual impactor(VI)for particle separation,a thermophoretic deposition chip for particle collection,and an extended-gate field-effect transistor(FET)for particle analysis.This system can realize on-site separation,collection,and analysis of aerosol particles without being influenced by environmental factors.In this study,the design of the VI is thoroughly analyzed by numerical simulation,and mixtures of different-sized silicon dioxide(SiO2)particles are used in an experimental verification of the performance of the VI and FET.Considering the low cost and compact design of the whole system,the proposed PM analysis microsystem has potential for PM detection under a wide range of conditions,such as heavily polluted industrial environments and for point-of-need outdoor and indoor air quality monitoring.

Construction of Ad-EGFP-BDNF vector and its expression in neural stem cells

BACKGROUND： Brain-derived neurotrophic factor （BDNF） provides nourishment to injured neurons. Neural stem cells can differentiate into neurons to repair neuronal injury in vivo. It has been hypothesized that continuous secretion of BDNF from neural stem cells could benefit brain injury repair. OBJECTIVE： To transfect BDNF and enhanced green fluorescent protein （EGFP） into neural stem cells with adenovirus vector and to observe expression of BDNF and EGFP in transfected neural stem cells. DESIGN, TIME AND SETTING： Observational, cellular, molecular study was performed at the Biochemistry Laboratory, Tongji University School of Medicine, China from July 2004 to September 2006. MATERIALS： Neural stem cells were provided by the Anatomy and Histoembryology Laboratory of Fudan University Medical School, China. METHODS： BDNF cDNA was extracted by reverse transcription polymerase chain reaction from the rat hippocampus. Following gene cloning and packaging by HEK293.BDNF, the EGFP gene was transfected into cultured neural stem cells with the Ad-EGFP-BDNF vector. BDNF-expressing neural stem cell clones were selected by G418 selection. MAIN OUTCOME MEASURES： EGFP expression and cell morphology were observed by fluorescent microscopy; neural stem cell expressing BDNF mRNA was examined by reverse transcription polymerase chain reaction; BDNF expression was detected by enzyme-linked immunosorbent assay from supematant of infected neural stem cells. RESULTS： High transfection efficiency was obtained using 5×10^8 virus titers to transfect neural stem cells. G418-resistant neural stem cell clones integrated BDNF mRNA fragments. Enzyme-linked immunosorbent assay results showed that BDNF expression in the supernatant increased with increasing culture time and peaked at 72 hours. CONCLUSION： Adenovirus-mediated BDNF and EGFP genes were successfully transfected into neural stem cells and were expressed in neural stem cells for a long period of time.

EB病毒转化的永生化B细胞系的建立及应用进展

人外周血B细胞来源于骨髓,是异质性的。EB病毒(Epstein-Barr virus,EBV)可在体外感染静止B细胞(naive B cells),利用其潜伏基因表达产物改变B细胞生命周期,从而形成永生化B淋巴母细胞系(B lymphoblastoid cell lines,B-LCLs),是近年来常用的B细胞永生化的有效方法。B-LCLs常被用作外周血B细胞的替代物和DNA的资源库,通过其单克隆抗体分泌功能、抗原提呈作用和相对稳定的遗传背景等广泛应用于生命科学的各个领域。