Species asynchrony stabilizes productivity over 20 years in Northeast China.

The stability of forest productivity can reflect the functioning of forest ecosystems. It is a crucial topic to understand the relationship between biodiversity and ecosystem functions in ecology. Although previous studies have made great progress in understanding the effects of diversity, species asynchrony, and other factors on community biomass and productivity, few studies have explored how these factors affect the temporal stability of productivity. In this study, we hypothesized that diversity, species asynchrony, and topography would directly or indirectly impact the temporal stability of productivity. To test this hypothesis, we used a multiple regression model and a piecewise structural equation model based on the inventory data over 20 years (5-year intervals) from 1992 to 2012 at Jingouling Forest Farm in Northeast China. Our results showed that species asynchrony was the main driving factor affecting the temporal stability of productivity. Structural diversity significantly decreased community stability, while species diversity had a nonsignificant effect on it. We found the combination of a multiple regression model and a piecewise structural equation model is an effective method for evaluating the factors that influence community stability. The effect of species asynchrony is crucial for understanding the ecological mechanisms underlying the diversity-stability relationship in mixed forests.

Advanced tubal pregnancy at 34 weeks with eclampsia and HELLP syndrome: a case report and literature re.

BACKGROUND: Tubal ectopic pregnancies in the late stages of pregnancy are uncommon, and reports on their complications are scarce. We present the case of a woman who had a tubal ectopic pregnancy at around 34 weeks and developed severe pre-eclampsia complications. CASE: A 27-year-old woman presented to our hospital several times with vomiting and convulsions. A physical exam revealed hypertension, scattered ecchymosis, and a large abdominal mass. A computed tomography (CT) scan performed in an emergency revealed an empty uterus, a stillbirth baby in the abdominal cavity, and a crescent-shaped placenta. Blood tests revealed that the patient had a low platelet count and clotting dysfunction. Laparotomy confirmed advanced right fallopian tube pregnancy without rupture, and salpingectomy was performed. Pathological examination revealed a significantly thickened tubal wall, adhesion of the placenta, and poor placental perfusion. CONCLUSION: The unusually thickened muscular layer of the tube may be one of the reasons for tubal pregnancy progressing to an advanced stage. Placenta adhesion and the special site to which it is attached reduce the risk of rupture. The detection of a crescent-shaped placenta on imaging may aid in the accurate diagnosis, distinguishing between abdominal and tubal pregnancy. Women with advanced ectopic pregnancy are more likely to develop pre-eclampsia and have poorer maternal-fetal outcomes. These negative outcomes may be influenced by abnormal artery remodeling, villous dysplasia, and placental infarction.

High Fe and Mn groundwater in the Nanchang, Poyang Lake Basin of China: hydrochemical characteristics and genesis mechanisms.

Based on the water quality test data of 257 groups of phreatic groundwater and 165 groups of confined groundwater in the Nanchang area and the redox conditions, acid-base conditions and the organic matter content in groundwater, we identified hydrochemical characteristics and genesis of groundwater with high Fe and Mn contents in Nanchang. The results showed that Fe and Mn exceeded the standard in both phreatic and confined groundwater. The over-standard rates of Fe and Mn in groundwater were 8.56-11.52% and 33.07-36.36%, respectively. The degree of pollution Fe and Mn in the confined groundwater is higher than that in the phreatic groundwater, and the degree of pollution caused by Mn is higher than that caused by Fe. The high Fe and Mn contents in groundwater were caused by the release of Fe and Mn minerals from the native environment due to changes in the groundwater environment of the study area. A mild redox environment (Eh < 100) and low pH value are favorable for Fe and Mn enrichment in groundwater. The presence of organic matter accelerates microbial activity and promotes the release of Fe and Mn from aquifer sediments. Therefore, the change in the native environment played an important role in the increase in Fe and Mn content in the study area.

Accumulation of Galactinol and ABA Is Involved in Exogenous EBR-Induced Drought Tolerance in Tea Plants.

Drought stress severely limits growth and causes losses in the yield of tea plants. Exogenous application of 24-epibrassinolide (EBR) positively regulates drought responses in various plants. However, whether EBR could contribute to drought resistance in tea plants and the underlying mechanisms has not been investigated. Here, we found that EBR application is beneficial for the drought tolerance of tea plants. The transcriptome results revealed that EBR could contribute to tea plant drought resistance by promoting galactinol and abscisic acid (ABA) biosynthesis gene expression. The content of galactinol was elevated by EBR and EBR-responsive CsDof1.1 positively regulated the expression of the galactinol synthase genes CsGolS2-1 and CsGolS2-2 to contribute to the accumulation of galactinol by directly binding to their promoters. Moreover, exogenous EBR was found to elevate the expression of genes related to ABA signal transduction and stomatal closure regulation, which resulted in the promotion of stomatal closure. In addition, EBR-responsive CsMYC2-2 is involved in ABA accumulation by binding to the promoters CsNCED1 and CsNCED2 to activate their expression. In summary, findings in this study provide knowledge into the transcriptional regulatory mechanism of EBR-induced drought resistance in tea plants.

Assessing scale-dependent effects on Forest biomass productivity based on machine learning.

Estimating forest above-ground biomass (AGB) productivity constitutes one of the most fundamental topics in forest ecological research. Based on a 30-ha permanent field plot in Northeastern China, we modeled AGB productivity as output, and topography, species diversity, stand structure, and a stand density variable as input across a series of area scales using the Random Forest (RF) algorithm. As the grain size increased from 10 to 200 m, we found that the relative importance of explanatory variables that drove the variation of biomass productivity varied a lot, and the model accuracy was gradually improved. The minimum sampling area for biomass productivity modeling in this region was 140 × 140 m. Our study shows that the relationship of topography, species diversity, stand structure, and stand density variables with biomass productivity modeled using the RF algorithm changes when moving from scales typical of forest surveys (10 m) to larger scales (200 m) within a controlled methodology. These results should be of considerable interest to scientists concerned with forest assessment.

CsGSTU8, a Glutathione S-Transferase From Camellia sinensis, Is Regulated by CsWRKY48 and Plays a Positive Role in Drought Tolerance.

Glutathione S-transferases (GSTs) constitute a large family of enzymes with a wide range of cellular functions. Recently, plant GSTs have gained a great deal of attention due to their involvement in the detoxification of electrophilic xenobiotics and peroxides under adverse environmental conditions, such as salt, cold, UV-B and drought stress. A previous study reported that a GST gene (CsGSTU8) in tea plant was distinctly induced in response to drought, suggesting this gene plays a critical role in the drought stress response. In this study, by using quantitative real-time PCR (qRT-PCR) and ß-glucuronidase (GUS) reporter lines, we further demonstrated that CsGSTU8 was upregulated in response to drought stress and exogenous abscisic acid (ABA) treatments. Overexpression of CsGSTU8 in Arabidopsis resulted in enhanced drought tolerance as indicated by the improved scavenging of excess amounts of reactive oxygen species (ROS) under drought conditions. Furthermore, we found that CsWRKY48 acts as a transcriptional activator and that its expression is induced in response to drought stress and ABA treatment. Electrophoretic mobility shift assays (EMSAs), dual-luciferase (LUC) assays and transient expression assays in tea plant leaves revealed that CsWRKY48 directly binds to the W-box elements in the promoter of CsGSTU8 and activates its expression. Taken together, our results provide additional knowledge of drought stress responses in tea plant.

The Effect of Torsional Vibration in Longitudinal-Torsional Coupled Ultrasonic Vibration-Assisted Grinding of Silicon Carbide Ceramics.

Rotary longitudinal-torsional coupled ultrasonic vibration-assisted grinding (LTUAG) is a new manufacturing method that can improve the grinding ability of silicon carbide ceramics. However, compared with longitudinal ultrasonic vibration-assisted grinding (LUAG), the role of torsional vibration in the grinding process is unclear. In this study, an effective method for measuring longitudinal-torsional coupled ultrasonic vibration amplitude and an experimental setup for measuring actual amplitude during grinding are proposed. The trajectory of the abrasive grains under the same grinding parameters and the same longitudinal amplitude during LTUAG and LUAG are analysed. Ultrasonic amplitude curves under the condition of tool rotation are then measured and analysed. Finally, the effect of torsional vibration on grinding force and surface roughness under the same grinding conditions is explained. Experimental analysis shows that the introduction of torsional vibration has little effect on the trajectory length and does not change the number of interference overlaps between abrasive grain tracks. Torsional vibration will only increase the cutting speed during grinding and reduce the undeformed chip thickness, which will reduce the grinding force and improve the surface roughness of LTUAG.

Overexpression of CsSnRK2.5 increases tolerance to drought stress in transgenic Arabidopsis.

Drought is a major factor limiting crop productivity and quality. Sucrose non-fermenting-1 (SNF1)-related protein kinase 2s (SnRK2s) play critical roles in plant abiotic stress responses, especially in drought stress. However, knowledge regarding the functional roles of SnRK2s in drought stress and their underlying mechanisms is relatively limited in tea plant. In this study, CsSnRK2.5, a PEG 6000- and ABA-induced SnRK2 gene from tea plant, was overexpressed in Arabidopsis to investigate its potential function in drought stress response. The results showed that overexpression of CsSnRK2.5 resulted in enhanced drought tolerance, as indicated by an amelioration of the changes in various physiological indexes, including a decreased rate of water loss and decreased accumulation of ROS and MDA. In addition, CsSnRK2.5 overexpression conferred hypersensitivity to exogenous ABA, and transgenic plants exhibited improved ABA-mediated stomatal closure compared to WT plants. Moreover, the expression of some stress response genes, including AtRAB18 and AtRD29b, was more strongly induced in transgenic plants than in the WT when subjected to ABA and drought treatments. Taken together, our results indicate that CsSnRK2.5 is a positive regulator of ABA-regulated drought stress responses.

Overexpression of miR-124 Protects Against Neurological Dysfunction Induced by Neonatal Hypoxic-Ischemic Brain Injury.

Neonatal hypoxic-ischemic encephalopathy (HIE) is a major cause of lifelong disabilities worldwide, without effective therapies and clear regulatory mechanisms. MicroRNAs (miRNAs) act as a significant regulator in neuroregeneration and neuronal apoptosis, thus holding great potential as therapeutic targets in HIE. In this study, we established the hypoxia-ischemia (HI) model in vivo and oxygen-glucose deprivation (OGD) model in vitro. Zea-longa score and magnetic resonance imaging were applied to verify HI-induced neuronal dysfunction and brain infarction. Subsequently, a miRNA microarray analysis was employed to profile miRNA transcriptomes. Down-regulated miR-124 was found 24 h after HIE, which corresponded to the change in PC12, SHSY5Y, and neurons after OGD. To determine the function of miR-124, mimics and lentivirus-mediated overexpression were used to regulate miR-124 in vivo and in vitro, respectively. Our results showed that miR-124 overexpression obviously promoted cell survival and suppressed neuronal apoptosis. Further, the memory and neurological function of rats was also obviously improved at 1 and 2 months after HI, indicated by the neurological severity score, Y-maze test, open field test, and rotating rod test. Our findings showed that overexpression of miR-124 can be a promising new strategy for HIE therapy in future clinical practice.

Efficacy of Tirofiban Administered at Different Time Points after Intravenous Thrombolytic Therapy with Alteplase in Patients with Acute Ischemic Stroke.

OBJECTIVE: To evaluate the efficacy of tirofiban administered at different time points within 24 hours of intravenous thrombolysis with alteplase in acute ischemic stroke. METHODS: Patients who underwent intravenous thrombolysis with alteplase and fulfilled other inclusion criteria were randomly divided into 4 groups according to the time points of tirofiban administration: Group A (2 h), Group B (2-12 h), Group C (12-24 h), and Group D (control). The changes in National Institutes of Health Stroke Scale score, modified Rankin Scale score, and adverse events were analyzed. RESULTS: At 7 ± 1 day, the efficacy in Group A was better than that in Group C (P = .006) and Group D (P = .001), but there was no significant difference in the efficacy between Groups A and B (P = .268). Similarly, at 14 ± 2 d, the efficacy in Group A was better than that in Group C (P = .026) and Group D (P = .001), but there was no significant difference in the efficacy between Groups A and B (P = .394). As evaluated by the modified Rankin Scale, the prognosis in Groups A, B, and C was better than that in Group D (P = .042, .008, .027, respectively), which was unrelated to the time points of tirofiban administration. There was no significant difference in the incidence of adverse events among the four groups. CONCLUSIONS: Tirofiban combined with alteplase is effective and safe, and particularly beneficial when administered at 2 hour and 2-12 hours after intravenous thrombolysis with alteplase in acute ischemic stroke.

Experimental and theoretical study of three new benzothiazole-fused carbazole derivatives.

Three new D-π-A type compounds, each containing one benzothiazole ring as an electron acceptor and one N-ethylcarbazole group as electron donor, were synthesized and characterized by elemental analysis, NMR, MS and thermogravimetric analysis. The absorption and emission spectra of three compounds were experimentally determined in several solvents and were simultaneously computed using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The calculated reorganization energy for hole and electron indicates that three compounds are in favor of hole transport than electron transport. The calculated absorption and emission wavelengths are well coincident with the measured data. The calculated lowest-lying absorption spectra can be mainly attributed to intramolecular charge transfer (ICT). And the calculated fluorescence spectra can be mainly described as originating from an excited state with intramolecular charge transfer (ICT) character. The results show that three compounds exhibited excellent thermal stability and high fluorescence quantum yields, indicating their potential applications as excellent optoelectronic material in optical field.

Supersecondary structure prediction using Chou's pseudo amino acid composition.

Supersecondary structures (SSSs) are the building blocks of protein 3D structures. Accurate prediction of SSSs can be one important step toward building a tertiary structure from the specified secondary structure. How to improve the accuracy of prediction of SSSs by effectively incorporating the sequence order effects is an important and challenging problem. Based on a different form of Chou's pseudo amino acid composition, a novel approach for feature representation of SSSs is proposed. Amino acid basic compositions, dipeptide components, and amino acid composition distribution are incorporated to represent the compositional features of proteins. Each supersecondary structural motif is characterized as a vector of 36 dimensions. In addition, we propose a novel prediction system by using SVM and IDQD algorithm as classifiers. Our method is trained and tested on ArchDB40 dataset containing 3088 proteins. The highest overall accuracy for the training dataset and the independent testing dataset are 77.7 and 69.4%, respectively.

Beta-hairpin prediction with quadratic discriminant analysis using diversity measure.

On the basis of the features of protein sequential pattern, we used the method of increment of diversity combined with quadratic discriminant analysis (IDQD) to predict beta-hairpins motifs in protein sequences. Three rules are used to extract the raw beta-beta motifs sequential patterns for fixed-length. Amino acid basic compositions, dipeptide components, and amino acid composition distribution are combined to represent the compositional features. Eighteen feature variables on a sequential pattern to be predicted are defined in terms of ID. They are integrated in a single formal framework given by IDQD. The method is trained and tested on ArchDB40 dataset containing 3088 proteins. The overall accuracy of prediction and Matthew's correlation coefficient for the independent testing dataset are 81.7% and 0.60, respectively. In addition, a higher accuracy of 84.5% and Matthew's correlation coefficient of 0.68 for the independent testing dataset are obtained on a dataset previously used by Kumar et al. (Nucleic Acids Res 2005, 33, 154), which contains 2088 proteins. For a fair assessment of our method, the performance is also evaluated on all 63 proteins used in CASP6. The overall accuracy of prediction is 74.2% for the independent testing dataset.