Rapid Geometric Evaluation of Transportation Infrastructure Based on a Proposed Low-Cost Portable Mobile Laser Scanning System.

Efficient geometric evaluation of roads and tunnels is crucial to traffic management, especially in post-disaster situations. This paper reports on a study of the geometric feature detection method based on multi-sensor mobile laser scanning (MLS) system data. A portable, low-cost system that can be mounted on vehicles and utilizes integrated laser scanning devices was developed. Coordinate systems and timestamps from numerous devices were merged to create 3D point clouds of objects being measured. Feature points reflecting the geometric information of measuring objects were retrieved based on changes in the point cloud's shape, which contributed to measuring the road width, vertical clearance, and tunnel cross section. Self-developed software was used to conduct the measuring procedure, and a real-time online visualized platform was designed to reconstruct 3D models of the measured objects, forming a 3D digital map carrying the obtained geometric information. Finally, a case study was carried out. The measurement results of several representative nodes are discussed here, verifying the robustness of the proposed system. In addition, the main sources of interference are also discussed.

Feasibility of MRI based oxygenation imaging for the assessment of acute limb ischemia.

BACKGROUND: Acute limb ischemia (ALI) can lead to death and amputation. Evaluating the severity of ischemia is important but difficult, through current methods of examination. The purpose of this research was to demonstrate the feasibility of magnetic resonance imaging (MRI) susceptibility-based imaging techniques for use in assessing muscle oxygenation alterations in ALI. METHODS: ALI animal models were established in 11 rabbits. Their left iliac arteries were embolized by microspheres. MRI scans were conducted 24 hours before (Pre) and 1 hour (Post 1) and 3 hours (Post 2) after the procedure. A susceptibility model was used to calculate skeletal muscle oxygenation extraction fraction (SMOEF) and relaxation rate (R2'). T2 weighted (T2w) imaging and diffusion-weighted (DW) imaging were performed. RESULTS: The average calf muscle SMOEF in the embolized hindlimbs increased from 0.43±0.02 (Pre) to 0.48±0.02 (Post 1) and 0.50±0.02 (Post 2), both P<0.05. The R2' value increased from 13.01±2.31 s-1 (Pre) to 16.78±2.28 s-1 (Post 1) and 17.90±3.29 s-1 (Post 2), both P<0.05. No significant changes of SMOEF and R2' were found after embolization in the contralateral hindlimbs. Apparent diffusion coefficient (ADC) values derived from DW imaging remained unchanged at different stages compared to before the procedures (all P>0.05). No abnormal signals were observed in the anatomical T2w images at Post 1 and Post 2. CONCLUSIONS: This study demonstrates the feasibility of using SMOEF for the assessment of oxygenation alterations in ALI models. SMOEF is more sensitive than T2w and DW imaging in detecting acute muscle ischemia at an early stage.

A feasibility study of using noninvasive renal oxygenation imaging for the early assessment of ischemic acute kidney injury in an embolization model.

PURPOSE: To investigate the feasibility of using MRI based oxygenation imaging for early assessment of ischemic acute kidney injury (AKI) in an embolization model. METHODS: Ischemic AKI model was induced in 40 rabbits by injection of microspheres into the right renal arteries. Animals were grouped according to the dose of microspheres: Severe AKI group, 2.0 mg (N = 10); Moderate AKI group, 1.0 mg (N = 10); Mild AKI group, 0.5 mg (N = 10); Control group, saline without microspheres (N = 10). A serial MRI examination was performed at intervals of 1 h, 1 day, 1 week and 4 weeks to evaluate the deterioration of renal function. A multi-echo ASE sequence was implemented for renal oxygenation measurement 1 h after surgery. Pathological examinations were performed 4 weeks after the surgery. RESULTS: In renal cortex, renal oxygen extraction fraction (OEF) raised significantly after embolization procedures in all experimental groups (severe AKI: 0.39 ±â€¯0.05, P < 0.05; moderate AKI: 0.36 ±â€¯0.03, P < 0.05; mild AKI: 0.34 ±â€¯0.02, P < 0.05) compared to the control group (0.29 ±â€¯0.02). In outer medulla, significant difference was observed between control group (0.29 ±â€¯0.03) and severe AKI group (0.35 ±â€¯0.03, P < 0.05), and between control group and moderate AKI group (0.34 ±â€¯0.04, P < 0.05). Corresponding lesions were found in pathological examinations 4 weeks after the procedure. CONCLUSION: This study demonstrates the feasibility of using oxygenation imaging to assess the embolization induced ischemic AKI at an early stage.

Socioeconomic inequalities and occupational injury disability in china: a population-based survey.

OBJECTIVE: To estimate the prevalence of occupational injury disability (OID) and to examine the socioeconomic status of OID in China. METHODS: The data derived from the China National Sample Survey on Disability in 2006 involving people aged 16-59 years old. Descriptive statistics are used to measure OID's prevalence, and a binary logistic regression is used to identify the risk factors. RESULTS: The population-weighted prevalence of OID is 1.81 (95% confidence interval (CI): 1.67-1.94). Socioeconomic risk factors include male sex, older age, living in urban areas, junior high school education, income below the poverty line, a lack of occupational injury insurance, living in the western region and working in high-risk occupations. CONCLUSIONS: OID is common among Chinese people aged 16-59 years old. Being male or older and having a lower income are risk factors for OID, similar to the results of previous research, but education is different. More training and education needs to be implemented to prevent OID.