[Responses of radial growth of Larix principis-rupprechtii at different densities to drought events]. / 不同密度华北落叶松径向生长对干旱事件的响应.

In recent years, a surge in drought occurrences has dramatically impacted tree growth worldwide. We examined the ecological resilience of Larix principis-rupprechtii plantations with varying densities (1950, 2355, and 2595 trees·hm-2) at the Saihanba Mechanical Forest Farm, by extracting the increment cores using the standard dendrochronological method to measure individual-tree basal area increments (BAI) as part of our assessment of ecological resilience, including resistance (Rt), recovery (Rc), and resilience (Rs). The results showed that drought events occurred in 2006-2010, 2015, and 2018. The Rt for L. principis-rupprechtii plantations varied from 0.76 to 2.01 across three drought events, indicating generally high resistance, except for the plantation with 2355 trees·hm-2 during the second dry year (Rt=0.69). The Rt for the plantation with 2595 trees·hm-2 significantly decreased across all drought events, while no significant change was observed in the plantations with 1950 and 2355 trees·hm-2. The Rc showed no differences in response to a single drought event across plantation densities, with a significant upward trend for all the densities with each occurrence of drought event. There was no significant difference in the resilience of different densities of L. principis-rupprechtii to the first drought event, whereas the plantation with 2595 trees·hm-2 exhibited significantly lower Rs during the second and third drought events compared with 1950 and 2355 trees·hm-2, respectively. During the 2015 drought event, plantation with 2595 trees·hm-2 experienced a significant growth decline (radial growth change rate was -26.5%), while no such decline was observed in the plantations with 1950 and 2355 trees·hm-2. Overall, the plantation with 2595 trees·hm-2 demonstrated the lowest resilience to drought events.

Trends of physical activity and recreational screen time among Chinese children and adolescents: a national study from 2017 to 2019.

BACKGROUND: The prevalence of physical inactivity and sedentary behavior among children and adolescents is a growing public health concern. This study aims to examine the trends in Physical Activity (PA) and Recreational Screen Time (RST) amongst children and adolescents in China, considering variations in genders, school levels, areas (urban versus rural), and regions (north versus south). The findings provide a foundation to guide policy and strategy making for future health promotion and development. METHODS: An annual national cross-sectional survey was conducted in China from 2017 to 2019 cumulatively involving 52,503 (48% female) children and adolescents from grades 4 to 12 (aged 12.72 ± 2.12). Data on PA and RST were collected through self-administered questionnaires. Weighted least squares regression was used to analyze the trends and differences in PA and RST among the participants' profiles. RESULTS: There was an annual decreased in PA compliance rate of approximately 3.43% (95% CI: 0.79-6.08%) for primary school students, primarily among males residing in rural areas, and in northern regions. Middle school students experienced a yearly decrease of about 5.23% (95% CI: 2.55-7.92%) in PA compliance across all genders, regions, and urban areas. Similarly, the RST compliance rates for primary school students declined by approximately 3.18% (95% CI: 1.57-4.78%) annually for all genders and areas, but only in the northern regions. CONCLUSIONS: This research highlights a downward trend in PA and RST compliance amongst Chinese children and adolescents, with variations based on school level, gender, area, and region. Urgent policies and interventions are imperative to promote PA while mitigating excessive RST within these populations.

The effects of COVID-19 on the Physical Activity and Recreational Screen Time among Chinese children and adolescents.

Background: The lack of Physical Activity (PA) and prolonged Recreational Screen Time (RST) among children and adolescents has been exacerbated during the COVID-19 pandemic, causing this issue to escalate into a crucial public health concern. This study aims to investigate the trends in PA and RST among Chinese children and adolescents from 2019 to 2022, thereby analyzing the short-term and long-term effects of the pandemic on PA and RST among Chinese children and adolescents. Methods: A nationally representative sample of Chinese primary, middle, and high school students was surveyed annually between September and December from 2019 to 2022 using a consistent set of questionnaires. Trends in PA and RST across different school levels, genders, areas (urban/rural), and regions (north/south) were analyzed using Segmented Linear Regression. Results: From 2019 to 2022, the PA and RST of children and adolescents displayed an inverted U-shaped trend, initially increasing and subsequently declining. Specifically, from 2019 to 2021, the PA of children and adolescents significantly increased but dramatically declined from 2021 to 2022. This trend in PA is more pronounced among primary, male, urban, and northern children and adolescent. The RST of children and adolescents increased from 2019 to 2020 but significantly decreased from 2020 to 2022. This trend in RST is more pronounced among primary, urban, and southern children and adolescent. Conclusions: This research unveils the effects of the pandemic on PA and RST in children and adolescents, suggesting short-term beneficial and long-term adverse effects on PA and short-term adverse and long-term beneficial effects on RST. These findings provide a foundation for formulating policies related to children and adolescents' PA and RST during the pandemic.

[Responses of radial growth of Larix principis-rupprechtii to abrupt warming]. / 华北落叶松径向生长对升温突变的响应.

To investigate the impacts of abrupt warming on tree growth, we collected tree ring cores from larch (Larix principis-rupprechtii) in three different sites, including Saihanba National Nature Reserve, Pangquangou National Nature Reserve, and Fengning Qiansongba National Forest Park. Based on the tree ring method, Mann-Kendall test was used to examine the occurrence time of temperature rise mutation. We further analyzed the radial growth law of larch before and after the temperature mutation and its correlation with the monthly climate data. The results showed that the sudden temperature rise occurred in the Saihanba area in 1987, the Fengning area in 1989, and the Pangquangou area 1994. Before the sudden warming, there was no significant trend for the radial growth in all the three regions. After the sudden warming, however, it decreased significantly (with a decrease rate of 0.08·10 a-1) in Saihanba area. The radial growth of larch increased significantly in Pangquangou area (with an increase rate of 0.10·10 a-1), while no significant change was observed in the Fengning area. Before the sudden warming, there was a significant positive correlation between the radial growth of larch in the Saihanba area and the highest temperature in May and June. After the sudden warming, there was a significant positive correlation with precipita-tion in July, and a highly significant positive correlation with the standardized precipitation evapotranspiration index(SPEI) from September of the previous year to July. Prior to the sudden warming, there was no significant relationship between the radial growth of larch in the Pangquangou area and monthly climate factors. However, after the sudden warming, a significant positive correlation was found with the lowest temperature in September of the pre-vious year. Before the sudden warming, the radial growth of larch in Fengning area was significantly negatively correlated with the lowest average temperature in July. After the sudden warming, it showed a significant negative correlation with the average and highest temperatures in June. Accordingly, the radial growth of larch in the Saihanba area experienced drought stress following a sudden temperature change. If temperature continues to rise in the future, larch in the Fengning area would also face drought stress. Conversely, warming conditions would be beneficial for the radial growth of larch in the Pangquangou area.

Association between physical activity, sedentary time, and physical fitness of female college students in China.

BACKGROUND: Prior research has highlighted the importance of Physical Activity (PA), Sedentary Time (ST), and Physical Fitness (PF) for health. However, there is limited research on the association between PA, ST, and PF in the context of female college students, particularly in Eastern cultures. Therefore, the purpose of this study was to investigate the association between PA, ST, and PF among Eastern female college students to inform policy and practice. METHODS: The study was conducted from February to May 2022 at East China Normal University, Shanghai, China. A total of 512 Chinese female college students participated in this study through snowball sampling. Participants' PA and ST were investigated using the International PA Questionnaire, and PF was measured using the Chinese National Student Physical Fitness Test. Independent samples t-test and binary logistic regression were used to compare the differences in PF between Active Participants (AP) and Inactive Participants (IP), as well as between Low Sedentary Participants (LSP) and High Sedentary Participants (HSP). Multinomial logistic regression was used to compare the differences in PF between Active and Low Sedentary Participants (ALSP), Active and High Sedentary Participants (AHSP), Inactive and Low Sedentary Participants (ILSP), and Inactive and High Sedentary Participants (IHSP). Data analysis was performed using Statistical Package for the Social Sciences version 28. The level of significance was set at 0.05. RESULTS: AP showed significantly higher cardiorespiratory fitness (p < 0.05) and overall fitness (p < 0.01) than IP. Compared to IP, AP was less likely to be classified as unfit in terms of cardiorespiratory fitness [Odds Ratio (OR), 0.57; 95% Confidence Interval (CI), 0.38-0.85; p < 0.05]. Compared to IHSP, ALSP (OR, 0.44; 95% CI 0.25-0.76; p < 0.01) and AHSP (OR, 0.54; 95% CI 0.32-0.93; p < 0.05) were less likely to be classified as unfit in terms of cardiorespiratory fitness. Furthermore, compared to IHSP, AHSP (OR, 1.66; 95% CI 1.02-2.70; p < 0.05) and ILSP (OR, 2.09; 95% CI 1.16-3.77; p < 0.05) were more likely to be classified as unfit in terms of their flexibility. CONCLUSION: There was a positive association between PA, cardiorespiratory fitness, and overall fitness. There was also an association between cardiorespiratory fitness, flexibility, and the combination of PA and ST. These findings suggest that both PA and ST can influence different PF items. Therefore, we recommend that public health policy and practice for college female students should consider PF items when selecting different PA and ST intervention strategies.

Relationship Between Lifestyle Habits and Health-Related Quality of Life of Recently Diagnosed Breast Cancer Patients: A Comparison Between Younger and Older Women in China.

Objective: The aim of this study was to evaluate the relationship between lifestyle habits and health-related quality of life (HRQoL) among different ages who were initially diagnosed with breast cancer (within the first 2 weeks) and to determine the contribution of lifestyle habits factors on HRQoL. Methods: Patients with breast cancer were recruited from 22 hospitals in 11 provinces or municipalities in northern and eastern China. The Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B) was used to measure HRQoL. Chi-square test, ANOVA, and multivariable generalized linear models were conducted to identify the differences in HRQoL between two age groups (age <50 years and ≥50 years) and to evaluate the contribution of lifestyle habits factors on HRQoL of patients with breast cancer. Results: About 1,199 eligible patients with breast cancer were used for analysis. Younger women (aged <50 years) appeared to show lower scores than older women (aged ≥50 years) in HRQoL subscales, including emotional well-being (p = 0.003), functional well-being (p = 0.006), breast cancer subscale (p = 0.038), and FACT-B Total scores (p = 0.028). Tea and alcohol consumption and being very satisfied with sleep and current life were the strongest predictors of higher HRQoL in younger group. Meanwhile, no coffee consumption, frequent participation in physical activities, high sleep satisfaction, and current life satisfaction were the key predictors of higher HRQoL in older women with breast cancer. Conclusion: The relationship of the nine lifestyle habit items with HRQoL differed among younger and older women. The associated variable of low HRQoL can help clinicians take intervention early in order to improve the prognosis of patients with breast cancer.

[Runoff-sediment relationship and erosion dynamic characteristics for two types of engineering deposits under rainfall condition]. / é™é›¨æ¡ä»¶ä¸‹ä¸¤ç§åœŸå£¤ç±»åž‹å·¥ç¨‹å †ç§¯ä½“å¡é¢æ°´æ²™å ³ç³»ä¸Žä¾µèš€åŠ¨åŠ›ç‰¹å¾.

The engineering deposits produced by the increasing frequency of production and construction activities are the main source of man-made soil erosion. In this study, we examined the change of runoff-sediment relationship and erosion hydrodynamic characteristics with the engineering deposits of aeolian sandy soil and red soil, based on simulated rainfall experiments with different gravel contents (0, 10%, 20%, 30%) and rainfall intensities (1.0, 1.5, 2.0, 2.5 mm·min-1). The results showed that the sediment yield rate of the aeolian sandy soil deposits gradually increased with the duration of rainfall. The sediment yield rate of red soil deposits under 1.0 mm·min-1 rainfall intensity increased first and then gradually stabilized. Under other rainfall densities, there was a trend of fluctuation after rapid decline, the greater the rainfall intensity and the smaller the gravel content, the more intense the fluctuation. When the gravel content was 0 and 10%, there were rills erosion on the slope surface of aeolian sandy soil accumulation, and the sediment yield rate of rill development stage was 6.74-57.40 times of that of the sheet erosion stage. The erosion process of red soil deposits could be divided into two stages: the loose particle erosion and the soil-rock erosion stage. The sediment yield rate of the loose particle erosion stage was 1.05-3.49 times that of the soil-rock erosion stage. In general, the sediment yield rate of two soil deposits increased with increasing rainfall intensity. The sediment yield rate fluctuated with the increases of gravel content at 1.0 and 1.5 mm·min-1, with a decreasing trend under >1.5 mm·min-1. The sediment yield rate of aeolian sandy soil deposits was 1.45-4.14 times of that of red soil deposits under the same rainfall and gravel content conditions. During the erosion process of aeolian sandy soil deposits, the runoff-sediment relationship changed from low sediment concentration to high sediment concentration, while there was a reverse relationship for red soil deposits. During the high sediment concentration period, the increasing rate of the sediment yield rate of aeolian sandy soil deposits was 1.94-37.60 times of that of red soil deposits. For low sediment concentration period, the decreasing rate of the sediment yield rate of red soil deposits was 1.40-21.30 times of that of aeolian sandy soil deposits. In general, the runoff power was better than the runoff shear force in describing the erosion dyna-mics of these two types of deposits. The critical runoff power increased with increasing gravel content. The critical runoff power of aeolian sandy soil deposits during the rill erosion stage (0.02-0.04 W·m-2) was two times of that of the sheet erosion stage, while the critical stream power was lower than that of the red soil deposits. These results provide a scientific reference for modelling soil erosion processes for engineering deposits.

[Erosion morphology and the characteristics of runoff and sediment yielding in platform-slope system of opencast coal mine]. / 露天矿排土场平台-边坡系统侵蚀形态及径流产沙特征.

In the open pit, runoff from the platform is large discharge and rapid afflux, which often results in serious gully erosion of dump slope. The study of erosion process under catchment conditions of the platform-slope system is still backward. In this study, field scouring experiments were conducted to investigate runoff characteristics and sediment yield processes of the platform-slope system under different flow discharges (48, 60, 72 and 84 L·min-1). Our results showed that rill erosion dominated the platform-slope system under the flow discharge of 48 L·min-1, and gully was formed under 60-84 L·min-1. The flow velocity of the platform and the slope showed an abrupting-fluctuating-stable trend with the duration of discharge. The flow velocity of the platform was smaller than that of the slope, with the magnitude of reduction at 8.3%-67.1%. The highest flow velocity appeared on the up-slop/down-slope, being 18.5%-44.6% higher than that of the middle-slope. In general, the sediment yield rate of the platform and the slope varied with the duration of discharge, with the sediment yield rate of the slope being 17.4 times as that of the platform. The ratio of gully width to depth showed substantial difference between the platform and slope. The platform generally had the largest ratio than the slope. For the slope, the largest ratio appeared on the middle-slop/down-slope, being 1.36-1.93 times as that of the up-slope. The morphology of rill and gully along the platform to down-slope presented in the form of "wide and shallow-narrow and deep-wide and shallow". Rill erosion mainly concentrated in the platform and the middle slope under the flow discharge of 48 L·min-1, contributed 29.9% and 26.8% of the total erosion volume, respectively. When the flow discharge increased to 60-84 L·min-1, the largest average across-section areas (1083.25-1737.86 cm2) formed on the up-slope accounted for 36.1%-44.7% of the total erosion volume. Our results provided evidence for modelling soil and water erosion of the platform-slope system in opencast coal mine.

Changes in Tea Plant Secondary Metabolite Profiles as a Function of Leafhopper Density and Damage.

Insect herbivores have dramatic effects on the chemical composition of plants. Many of these induced metabolites contribute to the quality (e.g., flavor, human health benefits) of specialty crops such as the tea plant (Camellia sinensis). Induced chemical changes are often studied by comparing plants damaged and undamaged by herbivores. However, when herbivory is quantitative, the relationship between herbivore pressure and induction can be linearly or non-linearly density dependent or density independent, and induction may only occur after some threshold of herbivory. The shape of this relationship can vary among metabolites within plants. The tea green leafhopper (Empoasca onukii) can be a widespread pest on tea, but some tea farmers take advantage of leafhopper-induced metabolites in order to produce high-quality "bug-bitten" teas such as Eastern Beauty oolong. To understand the effects of increasing leafhopper density on tea metabolites important for quality, we conducted a manipulative experiment exposing tea plants to feeding by a range of E. onukii densities. After E. onukii feeding, we measured volatile and non-volatile metabolites, and quantified percent damaged leaf area from scanned leaf images. E. onukii density had a highly significant effect on volatile production, while the effect of leaf damage was only marginally significant. The volatiles most responsive to leafhopper density were mainly terpenes that increased in concentration monotonically with density, while the volatiles most responsive to leaf damage were primarily fatty acid derivatives and volatile phenylpropanoids/benzenoids. In contrast, damage (percent leaf area damaged), but not leafhopper density, significantly reduced total polyphenols, epigallocatechin gallate (EGCG), and theobromine concentrations in a dose-dependent manner. The shape of induced responses varied among metabolites with some changing linearly with herbivore pressure and some responding only after a threshold in herbivore pressure with a threshold around 0.6 insects/leaf being common. This study illustrates the importance of measuring a diversity of metabolites over a range of herbivory to fully understand the effects of herbivores on induced metabolites. Our study also shows that any increases in leafhopper density associated with climate warming, could have dramatic effects on secondary metabolites and tea quality.

[Differences in hydraulic erosion processes of the earth and earth-rock Lou soil engineering accumulation in the Loess Region]. / é»„åœŸåŒºåœŸè´¨ä¸ŽåœŸçŸ³è´¨å¡¿åœŸå †ç§¯ä½“æ°´åŠ›ä¾µèš€è¿‡ç¨‹å·®å¼‚.

An indoor rainfall simulation experiment was conducted to examine the hydrodynamic characteristics, erosion characteristics, and erosion dynamics mechanisms of earth (excluding gra-vel) and earth-rock (gravel mass fraction 30%) Lou soil engineering accumulation in the Loess area across different rainfall intensities and slope gradients. Results showed that the presence of gravel changed the hydrodynamic characteristics of the engineering accumulation slope. The flow velocity, froude number, unit stream power, and unit energy of water-carrying section of the earth-rock slope were 1.7%-49.7%, 6.7%-60.6%, 2.0%-44.6% and 1.0%-26.7% lower than those of the earth slope, while the Manning roughness coefficient and runoff shear stress of the earth-rock slope were 6.2%-169.4% and 5.7%-79.3% higher than those of the earth slope respectively. Under the intensity of 2.0 and 2.5 mm·min-1, erosion rate of the earth-rock slope was 26.2%-89.9% lower than that of earth slope. The gravel significantly reduced slope erosion of the Lou soil engineering accumulation. Erosion rate and hydrodynamic parameters of the two accumulations were linearly related. The erodibility parameters of earth-rock slope were 56.1%-73.3% lower than that of earth slope. In the critical hydrodynamic parameters, runoff shear stress of earth-rock slope was 11.1% higher, while the stream power, unit stream power and unit energy of water-carrying section were 25.4%, 64.0% and 5.0% lower than those of the earth slope, respectively. The existence of gravel controlled rainfall erosion process on the slope of the engineering accumulation to some extent.

Effect of naturally restored grassland on the ephemeral gully erosion in the loess hilly and gully region.

Ephemeral gully erosion is an important erosion type in hilly and gully regions of Loess Plateau. While previous studies mainly focused on ephemeral gullies in agricultural land, little is known about the effects of naturally restored grassland on ephemeral gully erosion. In this study, taking the bare ephemeral gullies as the baseline, we conducted in-situ flushing tests to explore runoff and sediment yield characteristics and erosion mechanism of grassland ephemeral gullies under the runoff conditions of 5, 10, 15, 20 and 25 L·min-1. Compared to the bare ephemeral gully, average flow velocity, stable runoff rate, Reynolds number and Froude number of grassland ephe-meral gullies was reduced by 25.4%-67.3%, 8.4%-26.6%, 54.9%-80.5%, 18.6%-65.1%, respectively, whereas resistance coefficient was increased by 0.09-7.18 folds. Compared to the bare ephemeral gully, the maximum sediment yield rate, stable sediment yield rate, average sediment yield rate of grassland ephemeral gullies was decreased by 55.1%-90.9%, 61.8%-95.4%, and 64.8%-92.4%, respectively. The sediment yield reduction benefit of the naturally restored grassland under the discharge flow rate of 5-25 L·min-1 could reach 65.9%-88.8%, which decreased with increasing discharge flow rate. Compared to the bare ephemeral gully, average stream power and average shear stress of grassland ephemeral gullies was reduced by 54.9%-80.5% and 12.4%-51.1%, respectively, whereas the critical stream power and critical shear stress was increased by 1.43 folds and 33.7%, respectively. The average sediment yield of grassland and bare ephemeral gullies was signifi-cantly linearly related to average stream power and shear stress. Naturally restored grassland significantly increased the erosion resistance and reduced runoff erosion potential of ephemeral gullies.

The Shape-Memory Effect of Hindered Phenol (AO-80)/Acrylic Rubber (ACM) Composites with Tunable Transition Temperature.

To broaden the types and scope of use of shape-memory polymers (SMPs), we added the hindered phenol 3,9-bis[1,1-dimethyl-2-{b-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro-[5,5]-undecane (AO-80), which comprises small organic molecules, to acrylic rubber (ACM) to form a series of AO-80/ACM rubber composites. The structural, thermal, mechanical property, and shape-memory properties of the AO-80/ACM rubber composites were investigated. We identified the formation of intra-molecular hydrogen bonding between ⁻OH of AO-80 and the carbonyl groups and the ether groups of ACM molecules. The amount of AO-80 used can be adjusted to tailor the transition temperature. AO-80/ACM rubber composites showed excellent shape recovery and fixity. The approach for adjusting the transition temperature of AO-80/ACM rubber composites provides remarkable ideas for the design and preparation of new SMPs.

[Combining K-line to analyse the relationship between cervical range of motion of patients with ossification of cervical posterior longitudinal ligament and surgical prognosis].

OBJECTIVE: Combining K-line (the connecting line of the midpoint of C2 and C7 spinal canal on the cervical lateral X-ray film) to analyze the relationship between cervical range of motion of patients with ossification of posterior longitudinal ligament (OPLL) and surgical prognosis. METHODS: A total 42 patients with ossification of cervical posterior longitudinal ligament underwent cervical posterior single open-door laminoplasty between April 2014 and March 2017 were retrospectively ananyzed. The patients were dividing into K-line (+) group and K-line (-) group according to the position realationship of OPLL and K-line. The lesion of ossification of the posterior longitudinal ligament was not over than the K-line known as K-line (+). Conversely, the lesion of ossification of the posterior longitudinal ligament crossing the K-line was called K-line (-). Preoperative and postoperative 3 months JOA scores were observed, and postoperative 3 months JOA improvement rate were computed to assess patient's neurological function recovery. Preoperation and postoperative 3 months, OPLL occupation ratio (OOR), cervical lordotic angles (CLA) and cervical lordotic value (CLV) were measured respectively. The realationship between postoperative neurologic functional recovery in patients of CLV>0 group and CLV<=0 group was evaluated in different K-line subgroups. RESULTS: For the patients in K (+) group and K (-) group, preoperative CLA were (14.7±9.6)° and (-6.4±9.5)°(P<0.05) respectively, postoperative at 3 months CLA were (14.0±8.0)° and (-1.4±10.4)°(P<0.05) respectively; preoperative JOA scores were 10.9±3.2 and 11.2±2.5 (P>0.05) respectively, postoperative at 3 months JOA scores were 14.2±1.8 and 12.6±2.2 (P<0.05) respectively, and postoperative at 3 months JOA score improvement rate were (54.7±17.6)% and (25.5±15.7)%(P<0.05) respectively. In the K-line (+) group, there were 29 patients in CLV>0 group at 3 months after operation, with improvement rate of (52.3±17.2)%, and 4 patients in CLV<=0 group, with improvement rate of (72.2±7.8)%. The improvement rate of the patients in CLV<=0 group was significantly better than that of the patients in CLV>0 group (P<0.05). CONCLUSIONS: No matter whether the ossification of cervical posterior longitudinal ligament was classified as K-line (+) or K-line (-), the cervical posterior single open-door laminoplasty can improve the neurological symptoms of patients, especially the patients in the K-line(+) group with better prognosis. The patinets in K-line(+) group, when postoperative at 3 months CLV>0, their improvement rate was lower than that of the patients with postoperative at 3 months CLV<=0.

[Difference in nitrogen accumulation and translocation between semi-winterness and springness wheat.] / æ˜¥æ€§å’ŒåŠå†¬æ€§å°éº¦æ¤æ ªæ°®ç´ ç§¯ç´¯ä¸Žè¿è½¬ç‰¹å¾å·®å¼‚.

Nitrogen accumulation, translocation and allocation were investigated in a field experiment to find out the difference between six semi-winterness wheat cultivars and nine springness wheat cultivars that are mainly grown in Jiangsu. Results indicated that the average nitrogen accumulation amount (NAA) in the semi-winterness wheat cultivars was lower from the beginning of wintering to jointing stage, but higher from booting to maturity stage, compared with the springness wheat cultivars tested under the same rate of nitrogen fertilization. The amount of nitrogen accumulated between the beginning of wintering and jointing stage showed no significant difference between the two types of wheat cultivars, but that accumulated between anthesis and maturity in the semi-winterness wheat cultivars was higher than that in the springness wheat cultivars. The total N translocation amount (TNTA) and N accumulation amount to grains after anthesis (NAAA) were significantly higher in the semi-winterness wheat cultivars than those in the springness wheat cultivars, but the total N translocation efficiency (NTE), the contribution proportion of accumulated N (ANCP), and the contribution proportion of translocated N (TNCP) did not show significant difference between the two types of wheat cultivars. In leaves, the semi-winterness wheat cultivars showed lower TNTA, NTE and TNCP than the springness wheat cultivars, but in stem and sheath these N indexes were higher in the semi-winterness wheat cultivars, with a significant level for TNTA. These were significant differences in NAA, NAAA, TNTA and TNCP among cultivars with the same spring type or semi-winter type. According to the differences in nitrogen absorption, utilization and translocation among different wheat cultivars, nitrogen utilization efficiency could be improved by using approp-riate amount and reasonable proportion of nitrogen fertilizers at different developmental stages of wheat.

[Difference in responses of major tree species growth to climate in the Miyaluo Mountains, western Sichuan, China].

To explore the responses of different tree species growth to climate change in the semi-humid region of the eastern Tibetan Plateau, we investigated climate-growth relationships of Tsuga chinensis, Abies faxoniana, Picea purpurea at an altitude of 3000 m (low altitude) and A. faxoniana and Larix mastersiana at an altitude of 4000 m (high altitude) using tree ring-width chronologies (total of 182 cores) developed from Miyaluo, western Sichuan, China. Five residual chronologies were developed from the cross-dated ring width series using the program ARSTAN, and the relationships between monthly climate variables and tree-ring index were analyzed. Results showed that the chronologies of trees at low altitudes were negatively correlated with air temperature but positively with precipitation in April and May. This indicated that drought stress limited tree growth at low altitude, but different tree species showed significant variations. T. chinensis was most severely affected by drought stress, followed by A. faxoniana and P. purpurea. Trees at high altitude were mainly affected by growing season temperature. Tree-ring index of A. faxoniana was positively correlated with monthly minimum temperature in February and July of the current year and monthly maximum temperature in October of the previous year. Radial growth of L. mastersiana was positively correlated with monthly maximum temperature in May, and negatively with monthly mean temperature in February and monthly minimum temperature in March. In recent decadal years, the climate in northeast Tibetan Plateau had a warming and drying trend. If this trend continues, we could deduce that P. purpurea should grow faster than T. chinensis and A. faxoniana at low altitudes, while A. faxoniana would benefit more from global warming at high altitudes.

[Processes of earth road regolith erosion in loess area].

Based on field investigation, the processes of earth road regolith erosion were studied under indoor simulated rainfall. Results showed that the runoff initiation time for both regolith and earth road surface erosion decreased with the increasing rainfall intensity and slope steepness. With the increase in regolith thickness, the initiation time for earth road surface erosion lagged for 2-5 min. When the regolith thickness was ≤ 0.5 cm, the runoff rate turned to be stable at 2 min after runoff generation, and the average runoff rate increased with the increasing rainfall intensity and decreased with the increasing slope steepness. When the regolith thickness was ≥ 1.0 cm, runoff rate turned to be stable at 3 min after runoff generation, and the average runoff rate increased linearly with the rainfall intensity but exhibited a gradually decreasing trend after the first increment with the increasing slope steepness. The critical point for regolith erosion decreased with the increasing rainfall intensity and slope steepness. With the regolith thickness of ≤ 0.5 cm, the erosion rate increased with the increasing rainfall intensity, with the erosion rate ranging from 24.5% to 434.4%, and the erosion rates for 8° and 16° slopes were 2.4 times as those for 2° and 4° slopes. With the regolith thickness of 1.0 cm, the erosion rate turned to be stable about 9 min after runoff generation and increased with the increasing rainfall intensity and slope. With the increasing slope steepness, the erosion form changed from sheet erosion to rill erosion and then to headward erosion. The average erosion amount over 10 min single rainfall for the regolith thickness of ≥ 1.0 cm was 1.3 times as that for the regolith thickness of ≤ 0.5 cm, while it was 2.7 times as that at the stage of regolith erosion alone. With the regolith thickness of ≤ 0.5 cm, the erosion amount had a significant correlation with rainfall intensity, and runoff volume with slope steepness. With the regolith thickness of ≥ 1.0 cm, both runoff and sediment yields in 10 min single rainfall had a significant correlation with rainfall intensity. The proportion of regolith erosion to the combined erosion increased with the increasing regolith thickness, while the road erosion was the main form at small regolith thickness.

Human embryonic lung fibroblasts treated with artesunate exhibit reduced rates of proliferation and human cytomegalovirus infection in vitro.

BACKGROUND: Cytomegalovirus (CMV) pneumonia is a major cause of death in immunosuppressed patients. Despite the effective treatment with ganciclovir (GCV) and other antiviral agents, the mortality rate remains between 30% to 50%. Recently, the anti-malarial drug artesunate (ART) wasfound to exhibit significant anti-viral activity. Here, we examined the effects of ART on human cytomegalovirus (HCMV) infection and human embryonic lung fibroblast (HELF) proliferation in vitro. METHODS: HELFs infected with the GFP-expressing Towne-BAC strain of HCMV were divided into three treatment groups: Group I, cells treated with ART for 1.5 h before HCMV inoculation; Group II, cells infected with HCMV that was pre-treated with ART for 1.5 h before HCMV inoculation; Group III, cells that were treated with ART at 1.5 h post-HCMV inoculation. GFP expression was observed daily by fluorescence microscopy, and the number of GFP-positive cells in each experimental group was recorded at 4-5 days post-infection. At 10 days post-infection, the viability of cells in each group was recorded. GCV treatment was used as a control. RESULTS: While no significant effects on cytotoxicity, cell viability, viral infection rates, or antiviral activity were observed upon treatment of Group I or II cells with GCV or low levels of ART, the ART-treated Group III population exhibited significantly reduced rates of infection at drug concentrations higher than 12.5 µM. Similarly, we observed a GCV concentration-dependent reduction in the viral infection rate in Group III cells. Notably, ART-treated, but not GCV-treated, cells also exhibited decreased proliferation. The 50% cytostatic concentrations (CC50) and the half maximal inhibitory concentrations (IC50) of ART and GCV were 54.382 µM and 12.679 µM, and 3.76 M and 14.479 µM, respectively. CONCLUSIONS: In addition to its robust antiviral activity, ART inhibits proliferation of HCMV-infected lung fibroblasts, making it a potential next-generation drug for CMV pneumonia treatment and for reducing fibroproliferation and fibrosis in these patients.

Circulating High-Molecular-Weight (HMW) Adiponectin Level Is Related with Breast Cancer Risk Better than Total Adiponectin: A Case-Control Study.

The level of total adiponectin, a mixture of different adiponectin forms, has been reported associated with breast cancer risk with inconsistent results. Whether the different forms play different roles in breast cancer risk prediction is unclear. To examine this, we measured total and high molecular weight (HMW) adiponectin in a case-control study (1167 sets). Higher circulating HMW adiponectin was negatively associated with breast cancer risk after adjusting for menopausal status and family history of breast cancer (P=0.024). We analyzed the relationship between adiponectin and breast cancer risk in 6 subgroups. Higher circulating HMW adiponectin was also negatively associated with breast cancer risk (P=0.020, 0.014, 0.035) in the subgroups of postmenopausal women, negative family history of breast cancer, BMI>=24.0. Total adiponectin was positively associated with breast cancer (P=0.028) in the subgroup of BMI<=24.0. Higher HMW/total adiponectin ratio was negatively associated with breast cancer (P=0.019) in the subgroup of postmenopausal women. Interestingly, in the subgroup of women with family history of breast cancer, higher circulating total and HMW adiponectin were positively associated with breast cancer risk (P=0.034, 0.0116). This study showed different forms of circulating adiponectin levels might play different roles in breast cancer risk. A higher circulating HMW adiponectin is associated with a decreased breast cancer risk, especially in postmenopausal, without family history of breast cancer or BMI>=24.0 subgroups, whereas higher circulating HMW adiponectin levels is a risk factor in women with a family history of breast cancer. Further investigation of different forms of adiponectin on breast cancer risk is needed.

[Sediment transport characteristics at different erosion stages for non-hardened roads of the Shenfu Coalfield, west China].

Non-hardened roads formed in the production of the Shenfu Coalfield have a unique condition of underlying surface. The road surface is composed of a regolith layer with a certain thickness resulted from long-term rolling and thus, is characterized by weakened anti-scourabilty and anti-erodibility. In contrast, soil layer below the regolith has a higher bulk density and anti-erodibility. The processes of soil erosion on the non-hardened roads exhibit some differences under rainfall condition. The process of sediment transport and the relationship between sediment transport rate and erosion factors at different erosion stages were studied on non-hardened roads with slope degrees ranging from 3° to 12° (3°, 6°, 9°, 12°) by a field experiment under artificial rainfall. Results showed that the first peak of sediment transport on the regolith surface was observed at the sheet erosion stage. Sheet erosion occurred only at 3° slope degree, with an average variation coefficient of 0.07 for sediment transport rate. Rills in every testing began to develop at slope degrees of 6° to 12° about 15 min after runoff initiation. At the sheet erosion stage, the process of sediment transport fluctuated considerably at rainfall intensities of > 1.5 mm · min(-1), but the differences in its variation were little at the three slope degrees, with average variation coefficients of 0.20, 0.19 and 0.16, respectively. Rainfall intensity had a more significant impact on sediment transport rate than slope degree. The process of sediment transport at the rill erosion stage fluctuated, but the fluctuation was obviously smaller than that at the sheet erosion stage, with average variation coefficients of 0.05, 0.09 and 0.10 at the three slope degrees. Many wide and shallow rills evolved at the rill erosion stage. The sediment transport rate could be well predicted by a power function of rainfall intensity and slope degree at the sheet and rill erosion stages. The stable sediment transport rate for all the tests was linearly related to runoff rate and sediment concentration.