Improving the ecological network optimization with landscape connectivity: a case study of Neijiang City, Sichuan Province.

Rapid urbanization intensifies the fragmentation of landscape patches and affects the stability of ecosystems. The construction of an ecological network can effectively promote the connection of important ecological spaces and improve the landscape integrity. However, the landscape connectivity, directly affecting the stability of ecological network, was less considered in the ecological network construction of recent researches, which easily caused the instability of constructed ecological network. Therefore, this study introduced landscape connectivity index to establish a modified ecological network optimization method based on the minimum cumulative resistance (MCR) model. The results showed that, compared with the traditional model, the modified model focused on the spatially detailed measurement of regional connectivity, and emphasized the impact of human disturbance on ecosystem stability at the landscape scale. The constructed corridors in the optimized ecological network of the modified model not only effectively improved the connection degree between important ecological sources but also avoided the areas with low landscape connectivity and high obstacles to ecological flow, especially in the counties of Zizhong, Dongxing, and Longchang within the focal study area. The ecological network established by the traditional model and modified model generated 19 and 20 ecological corridors with lengths of 334.49 km and 364.35 km, respectively, and the number of ecological nodes was 18 and 22. Evaluated by the Gravity method, the modified model identified the important ecological corridors in the ecological network, and the energy transfer efficiency of the network was improved. This study provided an effective way to improve the structural stability of ecological network construction and can provide scientific support for regional landscape pattern optimization and ecological security construction.

Few-shot learning approach with multi-scale feature fusion and attention for plant disease recognition.

Image-based deep learning method for plant disease diagnosing is promising but relies on large-scale dataset. Currently, the shortage of data has become an obstacle to leverage deep learning methods. Few-shot learning can generalize to new categories with the supports of few samples, which is very helpful for those plant disease categories where only few samples are available. However, two challenging problems are existing in few-shot learning: (1) the feature extracted from few shots is very limited; (2) generalizing to new categories, especially to another domain is very tough. In response to the two issues, we propose a network based on the Meta-Baseline few-shot learning method, and combine cascaded multi-scale features and channel attention. The network takes advantage of multi-scale features to rich the feature representation, uses channel attention as a compensation module efficiently to learn more from the significant channels of the fused features. Meanwhile, we propose a group of training strategies from data configuration perspective to match various generalization requirements. Through extensive experiments, it is verified that the combination of multi-scale feature fusion and channel attention can alleviate the problem of limited features caused by few shots. To imitate different generalization scenarios, we set different data settings and suggest the optimal training strategies for intra-domain case and cross-domain case, respectively. The effects of important factors in few-shot learning paradigm are analyzed. With the optimal configuration, the accuracy of 1-shot task and 5-shot task achieve at 61.24% and 77.43% respectively in the task targeting to single-plant, and achieve at 82.52% and 92.83% in the task targeting to multi-plants. Our results outperform the existing related works. It demonstrates that the few-shot learning is a feasible potential solution for plant disease recognition in the future application.

Mesenchymal stem cells homing to rat lung emphysema followed by differentiation into pulmonary vascular endothelial cells / 中国组织工程研究

BACKGROUND:Mesenchymal stem cells have unique homing,immunoregulation and anti-inflammatory properties.After intravenous injection,mesenchymal stem cells can home to the damaged target organs and tissues,and function to repair damaged tissues.OBJECTIVE:To observe the pathological changes of lung tissues in rats with emphysema after mesenchymal stem cells transplantation.METHODS:Twenty-four female Wistar rats were randomly divided into experimental group,control group and healthy control group.In the first two groups,the model of pulmonary emphysema was established by the method of dropping porcine pancreatic elastase.BrdU-labeled mesenchymal stem cells were injected into the tail vein of the rats in the experimental group,and PBS was injected in the control group.After 14 days,the pathological changes of lung tissues were observed.Tumor necrosis factor-α level,alveolar wall apoptotic index,anti-CD34 and anti-BrdU immunohistochemical changes in the bronchoalveolar lavage fluid were detected.RESULTS AND CONCLUSION:Compared with the healthy control group,the tumor necrosis factor-α level and apoptotic index of alveolar wall cells increased (P ＜ 0.01),and the relative areas of anti-Brdu and anti-CD34 decreased (P ＜ 0.01) in the control group.Compared with the control group,the level of tumor necrosis factor-α and apoptotic index of alveolar wall cells decreased (P ＜ 0.01),and the relative area of anti-Brdu and anti-CD34 increased (P ＜ 0.01) in the experimental group.The histopathological findings showed that both the control group and the experimental group showed emphysema-like changes,but these changes were milder in the experimental group than the control group.To conclude,mesenchymal stem cells can inhibit inflammatory response and apoptosis in experimental emphysema,improve the pathological changes of the lung,and moreover,bone marrow mesenchymal stem cells can differentiate into lung vascular endothelial cells.

Functional differentiation of dopaminergic neurons derived from human embryonic stem cells / 中国组织工程研究

BACKGROUND: The in vitro differentiation methods of stem cell-derived dopaminergic neurons that serve as a cell source for the replacement therapy of Parkinson's disease are continuously optimized and improved, as well as the subsequent identification methods and testing indicators. OBJECTIVE: To observe the morphological development and electrophysiological characteristics of dopaminergic neurons differentiated from human embryonic stem cells so as to identify whether these differentiated cells have mature morphology and function under the current differentiation program. METHODS: Monolayer adherent method combined with dual-SMAD signaling inhibition was used to induce the directional differentiation of human embryonic stem cells into dopaminergic neurons. Then the cells were identified by light microscopy, electron microscopy and immunofluorescence, and the electrophysiological properties of dopaminergic neurons were detected by patch clamp electrophysiological technique. Herein, we evaluated the electrophysiological functions of dopaminergic neurons differentiated in vitro, with reference to the evaluation standard of dopaminergic neuron in vivo. RESULTS AND CONCLUSION: In this study, we successfully obtained dopaminergic neurons with mature morphology and functions differentiated from human embryonic stem cells in vitro. Findings from the subsequent electrophysiological test confirmed that dopaminergic neurons we acquired had electrophysiological properties in accordance with the evaluation standards of dopaminergic neurons in vivo. To conclude, the monolayer adherent method combined with dual-SMAD signaling inhibition can successfully induce the directional differentiation of human embryonic stem cells into dopaminergic neurons with mature morphology and functions.

Preparation and clinical evaluation of synaptophysin and chromogranin A monoclonal antibodies against immunohistochemistry / 中国免疫学杂志

Objective:To prepare the synaptophysin and chromogranin A monoclonal antibodies with clinical evalua -tion.Methods:The fuse gene (Syn and CgA) was designed and it was constructed on the expression vector pET-28a.Then ,the fusion protein was purified.After protein immunization , cell fusion and screening , the target antibodies were selected .Specificity study and correlation coefficient of Syn and CgA was evaluated by clinical sample comparison validation .Results:By screening,two antibodies 3D9 and 4A12,respectively,for Syn and CgA,were obtained.19 kinds of wax block organization were detected by 3D9,4A12 and control antibody(Leica).The statistical results were analyzed ,the results were in good agreement ,and the correlation coefficients were r=0.9892 and r =0.9939, respectively.Conclusion: This method is prepared to obtain the synaptophysin and chromogranin A antibodies successfully and both can be used for immunohistochemistry .This method can also provide some reference for the study of antibody .

[Effects of cadmium on protein tyrosine phosphorylation of mouse spermatozoa and the protective role of EGTA]. / é•‰å¯¹å°é¼ ç²¾å­è›‹ç™½é ªæ°¨é ¸ç£·é ¸åŒ–ä¿®é¥°çš„å½±å“åŠEGTA的保护作用.

In this study, we explored the effects of cadmium (Cd) on mouse sperm motility parame-ters, protein tyrosine phosphorylation and the location of tyrosine-phosphorylated targets using computer-assisted sperm analysis (CASA), western blot (WB) and immunofluorescence technique coupled to sperm in vitro culture method, respectively. The results showed sperm motility was inhibi-ted by Cd in a dose-dependent manner and when Cd increased to 1.0 µmol·L-1, sperm motility was inhibited significantly (P<0.05). Simultaneously, protein tyrosine phosphorylation was enhanced by Cd and in particular, the tyrosine phosphorylation of ～55 kDa proteins was greatly promoted when Cd concentrations were greater or equal to 1.0 µmol·L-1 (P<0.05). Importantly, these tyrosine-phosphorylated proteins were mainly localized in the middle piece of mouse sperm. However, when sperm was incubated with 30 µmol·L-1 ethylene glycol tetraacetic acid (EGTA) and 10 µmol·L-1 Cd concurrently, both the tyrosine phosphorylation of ～55 kDa proteins and sperm motility were not changed obviously (P>0.05). These results suggested that Cd may inhibit sperm motility by inducing the tyrosine phosphorylation of ～55 kDa proteins in the middle piece and EGTA could chelate Cd ions to relieve its toxicity. This study demonstrated that Cd induced the tyrosine phosphorylation of a specific subset of proteins and thus decreased sperm motility. Interes-tingly, EGTA acted as an inhibitor to block Cd from entering the sperm, which provided a novel research method for revealing the molecular mechanisms of reproductive toxicity caused by Cd.

Bone marrow mesenchymal stem cell transplantation for treatment of emphysema:intravenous versus intratracheal approach / 中国组织工程研究

BACKGROUND:Bone marrow mesenchymal stem cel s transplantation can inhibit experimental emphysema inflammatory reaction and apoptosis, and has been experimental y confirmed to treat severe lung function impairment. OBJECTIVE:To explore the inhibitory effects of bone marrow mesenchymal stem cel s transplantation via different ways on inflammatory reaction and apoptosis due to experimental emphysema. METHODS:Female Wistar rats were randomly divided into control group, intravenous group and endotracheal group fol owing model establishment using fumigation plus intratracheal instil ation of porcine pancreatic elastase. In the latter two groups, bone marrow mesenchymal stem cel s from male rats were injected via the tail vein and the trachea, respectively. In the control group, rats were given PBS via he tail vein and trachea. At 14 days after transplantation, pathological changes of rat lung tissues were observed, cel apoptotic index in alveolar wal cel s and tumor necrosis factorαlevel in the bronchoalveolar lavage fluid were detected. RESULTS AND CONCLUSION:Compared with the control group, in the intravenous and endotracheal groups,the pathological changes of lung tissues were relieved, tumor necrosis factorαlevel and apoptosis index were reduced significantly (P0.05). These findings indicate that bone marrow mesenchymal stem cel s transplantation via the tail vein and trachea both can exert obvious therapeutic effects on emphysema. Moreover, cel transplantation via the tail vein is more convenient and easier than that via the trachea in the treatment of emphysema.

Epidemiological survey of asthma among children aged 0-14 years in 2010 in urban Zhongshan, China / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the prevalence, current treatment, and clinical characteristics of asthma, as well as the risk factors for this disease, among children aged 0-14 years in 2010 in urban Zhongshan, China.</p><p><b>METHODS</b>A total of 10 336 children aged 0-14 years were selected from urban Zhongshan by cluster random sampling. The Third National Childhood Asthma Epidemiological Questionnaire 2010 was used to analyze the prevalence, current treatment, and clinical characteristics of childhood asthma, as well as the risk factors for this disease.</p><p><b>RESULTS</b>Asthma was diagnosed in 179 cases (1.73%). The prevalence of asthma in male children was significantly higher than that in female children (2.25% vs 1.16%; P<0.01). Of the 179 patients, severe attacks were common in 104 cases (58.1%), 110 cases (61.5%) had slow onset, 102 cases (57.0%) had gradually relieved conditions, 61 cases (34.1%) suffered from asthma during seasonal transition, and 150 cases (83.8%) developed asthma due to respiratory tract infection. Among all asthmatic children, 71.5% had been treated with inhaled corticosteroids, and 71.5% had been treated with bronchodilator. The multivariate logistic regression analysis showed that a history of penicillin allergy, a family history of allergy, food allergy, eczema, allergic rhinitis, cesarean delivery, family mould, and perinatal passive smoking were independent risk factors for childhood asthma.</p><p><b>CONCLUSIONS</b>The prevalence of childhood asthma in urban Zhongshan is on a high level, and is associated with gender. The treatment of asthma has been standardized, but still needs further improvement. The onset of asthma attack is influenced by various factors.</p>

Bone marrow mesenchymal stem cell transplantation suppresses emphysema-induced inflammation and apoptosis / 中国组织工程研究

BACKGROUND:Bone marrow mesenchymal stem cells transplantation can change the surrounding microenvironment through paracrine mechanisms, and can be employed for treatment of serious damage to lung function through the promotion of angiogenesis, inhibition of apoptosis and maintaining functional stability of autonomic nervous system. OBJECTIVE:To observe the inflammatory reaction in experimental emphysema and inhibition of apoptosis through bone marrow mesenchymal stem cells transplantation. METHODS:Twenty-four Wistar female rats were randomly divided into three groups:healthy control group, model group and experimental group. In the latter two groups, smoking and endotracheal instil ation of porcine pancreatic elastase were performed to establish emphysema models. After modeling, bone marrow mesenchymal stem cells were injected via tail vein in the experimental group. Pathological changes of the lung, the level of tumor necrosis factor-alpha and cellnumber in the bronchoalveolar lavage fluid as wel as apoptotic index in lveolar wal s were detected after celltransplantation. RESULTS AND CONCLUSION:In the model and experimental groups, pathological changes of lung tissues were observed to different extent. The lung pathological changes were slighter in the experimental group than the model group (P<0.01). The level of tumor necrosis factor-alpha and apoptotic index in lung tissue were lower in the experimental group than the model group (P<0.01). These findings indicate that bone marrow mesenchymal stem cells can improve emphysema pathological y through inhibition of inflammatory response and apoptosis in experimental emphysema.