66 research outputs found
Site type classification for the shelter-forest ecological project along the Tarim Desert Highway
Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environment, the irrigation with saline water, and large-scale linear project makes this classification of site types most unique and significant. It adopted a three-level classification system integrating the dominant factors and restrictive factors in regard to their impacts on plant survival and growth as well as on the protective property. Six site type districts were classified based on the medium-scale geomorphic unit, the windblown sand damages, and the major production facilities; 21 site type groups were obtained according to the small-scale geomorphic type, terrain, and wind regime; 36 site types were further classified based on the salt contents of the underground water and soil types. Especially, in this study, spatial distribution of the six site type districts along the desert highway is continuous, which is unique and different from that of most other classifications. In addition, the salt-stress tolerance threshold of the main afforestation plant species to underground water have been set to 8 g/L and 15 g/L according to selective breeding tests and the salinity spatial distribution of the underground water. Thus, the underground water with salinity lower than 8 g/L is defined as light saline water in this area
Mesenchymal Progenitor Cells and Their Orthopedic Applications: Forging a Path towards Clinical Trials
Mesenchymal progenitor cells (MPCs) are nonhematopoietic multipotent cells capable of differentiating into mesenchymal and nonmesenchymal lineages. While they can be isolated from various tissues, MPCs isolated from the bone marrow are best characterized. These cells represent a subset of bone marrow stromal cells (BMSCs) which, in addition to their differentiation potential, are critical in supporting proliferation and differentiation of hematopoietic cells. They are of clinical interest because they can be easily isolated from bone marrow aspirates and expanded in vitro with minimal donor site morbidity. The BMSCs are also capable of altering disease pathophysiology by secreting modulating factors in a paracrine manner. Thus, engineering such cells to maximize therapeutic potential has been the focus of cell/gene therapy to date. Here, we discuss the path towards the development of clinical trials utilizing BMSCs for orthopaedic applications. Specifically, we will review the use of BMSCs in repairing critical-sized defects, fracture nonunions, cartilage and tendon injuries, as well as in metabolic bone diseases and osteonecrosis. A review of www.ClinicalTrials.gov of the United States National Institute of Health was performed, and ongoing clinical trials will be discussed in addition to the sentinel preclinical studies that paved the way for human investigations
Attenuation of Vaccinia Tian Tan Strain by Removal of Viral TC7L-TK2L and TA35R Genes
Vaccinia Tian Tan (VTT) was attenuated by deletion of the TC7L-TK2L and TA35R genes to generate MVTT3. The mutant was generated by replacing the open reading frames by a gene encoding enhanced green fluorescent protein (EGFP) flanked by loxP sites. Viruses expressing EGFP were then screened for and purified by serial plaque formation. In a second step the marker EGFP gene was removed by transfecting cells with a plasmid encoding cre recombinase and selecting for viruses that had lost the EGFP phenotype. The MVTT3 mutant was shown to be avirulent and immunogenic. These results support the conclusion that TC7L-TK2L and TA35R deletion mutants can be used as safe viral vectors or as platform for vaccines
Assessment of AMSR-E sea ice concentration in ice margin zone using MODIS data
The AMSR-E sea ice concentration product with the spatial resolution of 6.25km is the finest published dataset of passive microwave in present. Based on the ice-water discrimination algorithm on visible image and data statistics, a method for AMSR-E sea ice concentration validation was given in this paper. To assess the AMSR-E ASI sea ice concentration product in ice margin zone, 12 clear sky samples were selected in Bering-Chukchi Seas to compare with the results come from MODIS images bases on channel 2 with 250m resolution during May and June, 2009. It shows that the average difference between the AMSR-E ASI and MODIS sea ice concentration is 0.672% with the RMS error of 16.838%. Accordingly, the ASI product is generally effectual and objective for mean state, while the uncertainty tends to be obvious in the ice margin zone. It is necessary to enhance the accuracy of product in sea ice margin zone by merging the passive microwave remote sensing data with higher resolution data, such as visible light remote sensing data. ? 2011 IEEE.EI
Study on the Synergetic Fire-Retardant Effect of Nano-Sb2O3 in PBT Matrix
Nano-Sb2O3 has excellent synergistic flame-retardant effects. It can effectively improve the comprehensive physical and mechanical properties of composites, reduce the use of flame retardants, save resources, and protect the environment. In this work, nanocomposites specimens were prepared by the melt-blending method. The thermal stability, mechanical properties, and flame retardancy of a nano-Sb2O3–brominated epoxy resin (BEO)–poly(butylene terephthalate) (PBT) composite were analyzed, using TGA and differential scanning calorimetry (DSC), coupled with EDX analysis, tensile testing, cone calorimeter tests, as well as scanning electron microscopy (SEM) and flammability tests (limiting oxygen index (LOI), UL94). SEM observations showed that the nano-Sb2O3 particles were homogeneously distributed within the PBT matrix, and the thermal stability of PBT was improved. Moreover, the degree of crystallinity and the tensile strength were improved, as a result of the superior dispersion and interfacial interactions between nano-Sb2O3 and PBT. At the same time, the limiting oxygen index and flame-retardant grade were increased as the nano-Sb2O3 content increased. The results from the cone calorimeter test showed that the peak heat release rate (PHRR), total heat release rate (THR), peak carbon dioxide production (PCO2P), and peak carbon monoxide production (PCOP) of the nanocomposites were obviously reduced, compared to those of the neat PBT matrix. Meanwhile, the SEM–energy dispersive spectrometry (EDX) analysis of the residues indicated that a higher amount of C element was left, thus the charring layer of the nanocomposites was compact. This showed that nano-Sb2O3 could promote the degradation and charring of the PBT matrix, improving thermal stability and flame retardation
Nuclease-free target recycling signal amplification for ultrasensitive multiplexing DNA biosensing
Ultrasensitive biosensing technologies without gene amplification held great promise for direct detection of DNA. Herein we report a novel biosensing method, combining target recycling signal-amplification strategy and a homemade electrochemical device. Especially, the target recycling was achieved by a strand displacement process, no needing the help of any nucleases. In the presence of target DNA, the recycling system could be activated to generate a cascade of assembly steps with three hairpin DNA segments. Each recycling process were accompanied by a disassembly step that the last hairpin DNA segment displaces target DNA from the complex at the end of each circulation, freeing targets to activate the self-assembly of more trefoil DNA structures. This biosensing method could detect target DNA at aM level and can distinguish target DNA from interfering DNAs, demonstrating its high sensitivity and high selectivity. Importantly, the biosensing method could work well with serum samples
A fully-automatic semi-supervised deep learning model for difficult airway assessment
Background: Difficult airway conditions represent a substantial challenge for clinicians. Predicting such conditions is essential for subsequent treatment planning, but the reported diagnostic accuracies are still quite low. To overcome these challenges, we developed a rapid, non-invasive, cost-effective, and highly-accurate deep-learning approach to identify difficult airway conditions through photographic image analysis. Methods: For each of 1000 patients scheduled for elective surgery under general anesthesia, images were captured from 9 specific and different viewpoints. The collected image set was divided into training and testing subsets in the ratio of 8:2. We used a semi-supervised deep-learning method to train and test an AI model for difficult airway prediction. Results: We trained our semi-supervised deep-learning model using only 30% of the labeled training samples (with the remaining 70% used without labels). We evaluated the model performance using metrics of accuracy, sensitivity, specificity, F1-score, and the area under the ROC curve (AUC). The numerical values of these four metrics were found to be 90.00%, 89.58%, 90.13%, 81.13%, and 0.9435, respectively. For a fully-supervised learning scheme (with 100% of the labeled training samples used for model training), the corresponding values were 90.50%, 91.67%, 90.13%, 82.25%, and 0.9457, respectively. When three professional anesthesiologists conducted comprehensive evaluation, the corresponding results were 91.00%, 91.67%, 90.79%, 83.26%, and 0.9497, respectively. It can be seen that the semi-supervised deep learning model trained by us with only 30% labeled samples can achieve a comparable effect with the fully supervised learning model, but the sample labeling cost is smaller. Our method can achieve a good balance between performance and cost. At the same time, the results of the semi-supervised model trained with only 30% labeled samples were very close to the performance of human experts. Conclusions: To the best of our knowledge, our study is the first one to apply a semi-supervised deep-learning method in order to identify the difficulties of both mask ventilation and intubation. Our AI-based image analysis system can be used as an effective tool to identify patients with difficult airway conditions. Clinical trial registration: ChiCTR2100049879 (URL: http://www.chictr.org.cn)
Multiple Anesthesia/Surgery Cannot Impair Reference Memory in Adult Mice
Postoperative cognitive dysfunction increases mortality and morbidity in perioperative patients. Numerous studies have demonstrated that multiple surgery/anesthesia during the neurodevelopmental period affects cognitive function, whereas a single anesthesia/surgery rarely causes cognitive dysfunction in adults. However, whether adults who undergo multiple anesthesia/surgery over a short period will experience cognitive dysfunction remains unclear. In this study, central nervous system inflammation and changes in cholinergic markers were investigated in adult mice subjected to multiple laparotomy procedures over a short period of time. The results showed that despite the increased expression of IL-6 and TNF-α in the hippocampus after multiple operations and the activation of microglia, multiple anesthesia/surgery did not cause a decline in cognitive function in adult mice. There were no changes in the cholinergic markers after multiple anesthesia/surgery
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