Search

Quercus rehderiana Hand.-Mazz. belongs to Quercus sect. Heteroallenes' of the Fagaceae family. It is widely distributed in forests with rocky and non-rocky desertification in Guizhou Province of Southwest China. However, our knowledge of the adaptation strategies of Quercus in forests with rocky desertification is surprisingly lacking. In this study, 16 leaf traits (morphological, anatomical, and chemical) of Quercus rehderiana were investigated in 15 individuals in five 20 × 20 m quadrants of forests with rocky and non-rocky desertification. The aim was to analyze their strategies of adaptation to arid and poor-soil environments in forests with rocky desertification. The results showed that Quercus rehderiana leaves in forests with rocky desertification had a greater leaf thickness, specific leaf area, abaxial epidermis thickness, and sponge mesophyll thickness but a lower leaf area than in forests with non-rocky desertification. Quercus rehderiana leaves in forests with rocky desertification had higher calcium and magnesium concentrations and a higher N:P ratio but lower potassium and phosphorus concentrations than in forests with non-rocky desertification. The results of principal component analysis showed that forests with rocky desertification tended to show resource-conserving strategies with thicker leaf tissue and a lower nutrient concentration, while forests with non-rocky desertification tended to show resource acquisition strategies with a greater leaf area and potassium concentration. In resource-poor environments, species that adopt conservative resource strategies are more likely to survive; therefore, we forecasted that more conservative, slow-growing Quercus rehderiana will be more stable over time. [ABSTRACT FROM AUTHOR]

Nitrogen (N) and phosphorus (P) play crucial roles in tea planting, but information on how the long-term excessive application of chemical N fertilizer affected N and P in subtropical tea plantations remains limited. In this study, soil and leaf samples were collected along a chronosequence of tea plantations (0-, 5-, 10-, 18- and 23-year-old plantations) with excessive N input but no P application to investigate the effects of planting age on N and P availability. Diverse soil N forms and P fractions, and the concentrations of leaf N and P were measured. The results showed that (1) N O 3 − -N and dissolved organic nitrogen (DON) concentrations in both topsoil and subsoil, and the N concentration of mature leaf showed significant upward trends with tea plantation age; (2) the concentrations of available phosphorus (AP), NaHCO3-Pi in labile P pool, NaOH-Pi and D.HCl-Pi in moderately labile P pool in both layers of soil and that the P concentration of mature leaf also increased with age; (3) the N concentration of mature leaves had closely significant logarithmic relations with N O 3 − -N concentration, while the TP (total P) concentration of mature leaves had significant positive correlations with AP; and (4) the ratio of N/P in tea leaves indicated a slightly P limitation in tea plantations. We concluded that the N O 3 − -N concentration, instead of TN (total N) of N H 4 + -N, would be a good indicator to reflect N availability for tea trees, and the increasing of N O 3 − -N concentration in soil has a diminishing promoting effect on the TN concentration of mature leaves. The long-term application of chemical N fertilizer had not lead to serious P limitation in subtropical tea plantations. Generally, our study could contribute to improving our understanding of N and P availability and optimizing fertilization management in subtropical tea plantations. [ABSTRACT FROM AUTHOR]

Rocky desertification (RD), a natural and human-induced process of land degradation in karst areas, has become the primary ecological disaster and one of the obstacles to sustainable ecological development in southwest China. Nevertheless, the variation of soil physical and chemical properties, bacterial and fungal communities, and their relationships in RD forests remains limited. Therefore, soil samples were collected from forests under four degrees of RD (NRD, non-RD; LRD, light RD; MRD, moderate RD; and SRD, severe RD) and subjected to high-throughput sequencing of 16S rRNA and ITS1 genes. The results showed a significant reduction in bacterial richness and diversity, while fungal richness and diversity decreased markedly and then showed a balanced trend with the increase in RD degree, indicating that bacteria and fungi did not present the same dynamics in response to the process of RD. The bacterial communities were dominated by Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi, while the fungal communities were dominated by Basidiomycota, Ascomycota, and Mortierellomycota. The PCoA and NMDS demonstrated significant differences in microbial communities in study sites, among which the fungal communities in non-RD forest and LRD forest clustered together, suggesting that fungal communities were more stable than bacteria in RD forest. The db-RDA, Mantel test, and random forest model confirmed the important role of soil BD, pH, SOC, AN, and AP in driving microbial diversity and communities. The IndVal analysis suggested that Chloroflexi, Patescibacteria, Atheliales, and Cantharellales with high indicator values were identified as potential bio-indicators for RD forests. This study could not only improve our understanding of bacterial and fungal community dynamics across RD gradients, but also could provide useful information for the further use of microorganisms as indicators to reflect the environmental changes and ecosystem status during forest RD. [ABSTRACT FROM AUTHOR]

Priority conservation areas are the key areas of biodiversity maintenance and ecosystem conservation. Based on a Maxent model, this study predicted the potential distribution of Pseudotsuga sinensis under the current climate and future climate change scenarios in Guizhou province, and then, assessed three kinds of priority conservation area under climate change. The results were as follows: (1) The AUC (Area Under the Curve) values showed excellent prediction accuracy of the model. (2) The areas of the potential habitats of P. sinensis forests under the current climate and future climate change scenarios were 22,062.85 km2 and 18,395.92 km2, respectively. As for their spatial distribution, the potential habitats of P. sinensis forests were distributed in the Bijie, Zunyi, Tongren, Liupanshui and Xingyi regions under the current climate, and in the Kaili region, in addition to the above-mentioned cities, under future climate change scenarios. (3) The total area of priority conservation areas under climate change was 25,350.26 km2. The area of the predicted sustainable potential habitats was 15,075.96 km2, of the vulnerable potential habitats was 7256.59 km2 and of the derivative potential habitats was 3017.71 km2. [ABSTRACT FROM AUTHOR]

Infrared transparent Ce‐doped Y3Fe5O12 (Ce: YIG, CexY3‐xFe5O12, x = 0, 0.12, 0.24, 0.36) ceramics were successfully produced by the solid‐state reaction using a hot‐press sintering process from the Y2O3, Fe2O3, and CeO2 powders. The phase structure, microstructure, infrared transmittance, and magnetic and magneto‐optical properties of the Ce‐doped Y3Fe5O12 ceramics were measured and analyzed. The in‐line transmittances of the Ce‐doped Y3Fe5O12 ceramics with the x = 0, 0.12, 0.24 (L = 0.5 mm) at 1550 nm were about 72%, 66.5%, and 57.6%, respectively. In the state of saturation magnetization, the Faraday rotation angle per centimeter (θF) of CexY3‐xFe5O12 (x = 0, 0.12, 0.24) ceramics measured by the light extinction method was 182.5, −410.4, and −958.3 deg./cm, respectively. The change of the θF was about −142.5 deg./cm when per 1at.% Ce was substituted in the dodecahedral site of YIG materials. The (Ce0.24Y2.76)Fe5O12 ceramics were determined as the optimized composition for its excellent infrared optical and magneto‐optical properties. [ABSTRACT FROM AUTHOR]

In this study, we collected plant material from Pseudotsugasinensis in Guizhou, China, and sequenced it. The complete chloroplast genome consisted of 122,243 bp, including a large single-copy (LSC) region, a small single-copy (SSC) region, and two inverted repeat regions like those in P. sinensis var. wilsoniana. The GC content of P. sinensis and P. sinensis var. wilsoniana are 38.7% and 38.8%, respectively. The reconstructed phylogenetic tree reveals that P. sinensis was a sister species to P. sinensis var. wilsoniana. Hence, the availability of the chloroplast genome of P. sinensis will promote further phylogenetic studies of the family Pinaceae. [ABSTRACT FROM AUTHOR]

Background. Trials on assessing the benefits of EGFR inhibitors in head and neck squamous cell carcinoma (HNSCC) patients have gradually been published. Nevertheless, the benefits of gefitinib in advanced HNSCC are still unknown. Methods. The Cochrane library, PubMed, and EMBASE databases were systematically searched from the inception dates to 17 July 2017, 18 July 2017, and 19 July 2017, respectively. The keywords "head and neck" and gefitinib were used to retrieve in articles and abstracts. An additional search for recently published randomized trials was performed from July 17, 2017, to April 18, 2018. Then we assessed the risk of bias of the included studies based on the Cochrane "Risk of Bias" tool. Quantitative analysis was carried out to evaluate the overall survival (OS), progression free survival (PFS), overall response rate (ORR), and grade 3-4 adverse effects by Review Manager 5.0.2 and the quality-of-life was analyzed in the included studies. Results. Seven randomized controlled trials and a total number of 1287 patients were involved. There were no significant differences in OS, PFS, or ORR between gefitinib and no gefitinib group (HR 1.07, 95% CI 0.93 to 1.22, and P=0.35; HR 0.84, 95% CI 0.69 to 1.04, and P=0.11; RR 1.04, 95% CI 0.90 to 1.20, and P =0.60, respectively). However, gefitinib alone was equivalent to chemotherapeutics (i.e., methotrexate; methotrexate + fluorouracil) in ORR in patients with recurrent HNSCC, and a trend of improvement in QOL in gefitinib group was showed. Toxicities revealed no differences except for diarrhea and skin toxicity (p=0.0003; p=0.03, respectively). Conclusion. For patients with advanced HNSCC, gefitinib cannot prolong the OS and PFS or improve ORR, and odds of skin toxicity and diarrhea increased. However, gefitinib alone is equivalent to methotrexate or methotrexate + fluorouracil and tends to improve QOL for recurrent patients. [ABSTRACT FROM AUTHOR]

In this study, the porous Mn2O3/TiO2 microspheres were prepared via a facile two-step hydrothermal method. Firstly, the Mn2O3 particles were obtained by the calcination of hydrothermal-synthesized MnCO3. Then the TiO2 layer was coated on the surface of the Mn2O3 particles by a hydrothermal-assisted liquid phase deposition (HA-LPD) method. The as-prepared samples were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and Brunauer-Emmett-Teller analyzer (BET), respectively. Moreover, the electrochemical performances of Mn2O3/TiO2 as an anode material in lithium ion batteries (LIBs) were also evaluated. The results indicated that, the specific capability of the Mn2O3/TiO2 composite material was about 452 mAh g−1 at the current density of 500 mA g−1 after 200 cycles, which was much higher than that of pristine Mn2O3 (313 mAh g−1). Meanwhile, the rate capacity of Mn2O3/TiO2 was 177 mAh g−1 at the current density of 4 A g−1, which was also higher than that of pure Mn2O3 (3 mAh g−1). Moreover, the Mn2O3/TiO2 composite material can still yield a specific capacity of 800 mAh g− 1 at the current density of 1 A g−1 after 1000 cycles. The enhanced electrochemical performances of Mn2O3/TiO2 composite material was mainly attributed to the synergistic effect between the Mn2O3 with high capacity and TiO2 with superior stability. [ABSTRACT FROM AUTHOR]

Objective: To compare the clinic value between the transcervical resection of myoma (TCRM) and laparoscopic myomectomy (LM), and investigate the favourable surgical approaches in women with intramural uterine myomas. Methods: From January 1, 2007 to December 31, 2011, 236 women undergoing TCRM (hysteroscopy group) and 392 women undergoing LM (laparoscope group) were studied retrospectively in The Third Affiliated Hospital of Zhengzhou University. The patients' general information, peri -operative characteristics, postoperative muscle healing, and pregnancy outcome were compared and analyzed. Results: The average operation time, the average intraoperative blood loss and the reduce perioperative hemoglobin level of hysteroscopic group and laparoscopic group were compared respectively, the difference had statistical significance (P <0.05). The transfer laparotomy operation rate, postoperative fever rate and menstrual period rate of hysteroscopic group and laparoscopic group were compared. There was no significant difference (P>0.05). In the follow-up of 181 cases of hysteroscopy group and 336 cases of laparoscopic group of patients, the muscular complete healing rate of postoperative 1 month, 3 months, 6 months were respectively comparison, the difference had statistical significance (P<0.05). The muscular complete healing rate of postoperative 12 months was no statistically significant difference (P=0.709). The postoperative pregnancy from fibroids weed out of time for the first time of hysteroscopic group and laparoscopic group was statistically significant difference (P<0.05). All patients with postoperative pregnancy appeared no pregnant uterine rupture. Conclusions: For intramural myoma, two kinds of operation modes are safe and reliable. The intraoperative bleeding and postoperative recovery by TCRM is better than the patientes treated by LM, so hysteroscopy surgery is superior to the laparoscopic surgery for the patients with intramural uterine myoma. [ABSTRACT FROM AUTHOR]

Long-term studies have revealed that forest species composition was shifting under environment change and disturbance induced by loss of large trees. Yet, few studies explicitly analyzed their impacts on composition concurrently. To learn more about impacts of environment change and disturbance on driving forest community, we investigated shifts in functional composition over past 24 years in an old-growth subtropical forest in southern China. We analyzed nine traits that are mainly related to leaf nutrients, photosynthetic capacity, hydraulic conductivity, and drought tolerance of plants and examined hypotheses: (1) The functional composition change over time was directional instead of random fluctuation, (2) drought-tolerant species increased their abundance under soil dryness, (3) both environmental change and disturbance related to changes of functional composition significantly, and (4) initial trait values of quadrats strongly influenced their subsequent change rates in quadrat level (10 × 10 m). We found that species composition had shifted to favor species with high leaf nutrient content, high photosynthesis rate, high hydraulic conductivity, low water-use efficiency, and high drought tolerance traits, which was due to soil dryness and disturbance. These two factors explained 47–58% of quadrats' trait value changes together. Considering rapidly increasing stem density, this pattern may indicate ecological processes of which disturbance provided numerous recruits of resource-acquisition strategy species and soil dryness conducted a selecting effect on shaping composition in the forest. Additionally, quadrats with initial trait values at the far end of change direction shifted faster in three traits, which also indicated that functional composition changes in quadrats were directional and homogenized. Our results implied that environment change and accompanied disturbance events possibly drove species composition change along a different trajectory in the subtropical forest that experienced high climatic variability. [ABSTRACT FROM AUTHOR]