385 research outputs found
Environmental burdens of groundwater extraction for irrigation over an inland river basin in Northwest China
Crop production is expected to increase by more than 50% to meet the demand of population growth in China in 2050 (FAO, 2017). Crop production in North China largely depends on irrigation, which is mainly from groundwater in Northwest China. Over-extraction of groundwater is decreasing groundwater levels, and threatening the fragile ecological systems of arid regions. How groundwater levels will change in order to meet the irrigation water requirement in Northwest China has not been extensively investigated to evaluate sustainability of agriculture and the cost to maintain groundwater levels. Here, we examine the dynamic relations between groundwater levels and the amount of irrigation water, by employing the Variable Infiltration Capacity model and an irrigation scheme, for the last three decades in Heihe River basin of China. The results show that on the average about 1.86 m decline of groundwater is attributable to the irrigation water consumption for the farmland area in Heihe River over the past three decades. In the scenario of ceasing irrigation activities, the groundwater level will be prevented to further decline about 3.06±0.4m under the future climate scenarios till 2050, but at the cost of crop production valued 64.2±8.4 billion CNY. Effective water-saving measures and strategies are expected to adopt to maintain both groundwater levels and agricultural productivity for the coming decades
Poly[[[μ-1,1′-(butane-1,4-diyl)diimidazole-κ2 N 3:N 3′](μ-cyclohexane-1,4-dicarboxylato-κ4 O 1,O 1′:O 4,O 4′)nickel(II)] 0.25-hydrate]
In the title coordination polymer, {[Ni(C8H10O4)(C10H14N4)]·0.25H2O}n, the coordination of the NiII ion is distorted octahedral. The 1,1′-(butane-1,4-diyl)diimidazole ligand and the cyclohexane-1,4-dicarboxylate dianion bridge metal centres, forming a two-dimensional (4,4) network. The network is consolidated by O—H⋯O hydrogen bonds between the statistically occupied water molecules and O atoms of the two carboxylate groups
Hypoxia-inducible factor-2a is associated with ABCG2 expression, histology-grade and Ki67 expression in breast invasive ductal carcinoma
<p>Abstract</p> <p>Background</p> <p>Breast cancer is the most common cancer and the leading cause of cancer mortality in women worldwide. Hypoxia is an important factor involved in the progression of solid tumors and has been associated with various indicators of tumor metabolism, angiogenesis and metastasis. But little is known about the contribution of Hypoxia-Inducible Factor-2a (HIF-2a) to the drug resistance and the clinicopathological characteristics in breast cancer.</p> <p>Methods</p> <p>Immunohistochemistry was employed on the tissue microarray paraffin sections of surgically removed samples from 196 invasive breast cancer patients with clinicopathological data. The correlations between the expression of HIF-2a and ABCG2 as well as other patients' clinicopathological data were investigated.</p> <p>Results</p> <p>The results showed that HIF-2a was expressed in different intensities and distributions in the tumor cells of the breast invasive ductal carcinoma. A positive staining for HIF-2a was defined as a brown staining observed mainly in the nucleus. A statistically significant correlation was demonstrated between HIF-2a expression and ABCG2 expression (p = 0.001), histology-grade (p = 0.029), and Ki67 (p = 0. 043) respectively.</p> <p>Conclusion</p> <p>HIF-2a was correlated with ABCG2 expression, histology-grade and Ki67 expression in breast invasive ductal carcinoma. HIF-2a could regulate ABCG2 in breast cancer cells, and could be a novel potential bio-marker to predict chemotherapy effectiveness. The hypoxia/HIF-2a/ABCG2 pathway could be a new mechanism of breast cancer multidrug-resistance.</p> <p>Virtual slides</p> <p>http://www.diagnosticpathology.diagnomx.eu/vs/2965948166714795</p
Maternal Prenatal Factors and Child Adiposity in Associations with Cardiometabolic Risk Factors in Term-Born Chinese Children at the Age of 2 Years
Early growth has long-lasting associations with adult metabolic health. However, the association of adiposity with cardiometabolic risk factors in toddlers remains poorly understood. This study aimed to examine the association of maternal prenatal factors and child adiposity with child cardiometabolic risk factors among boys and girls aged 2 years. This was a birth cohort study of 549 term-born children in Shanghai, China, with follow-up data at the age of 2-years. Child anthropometric and adiposity measurements included weight, length, and skinfold thickness (triceps, subscapular, and abdominal). Child cardiometabolic risk factors included random morning plasma glucose, serum insulin, lipids, and systolic and diastolic blood pressure (SBP, DBP). At 2 years, overweight/obesity (weight-for-length z score, ZWFL > 2) was associated with 12.6 (95%CI 7.7, 17.4) mmHg higher SBP, and 7.9 (4.1, 11.8) mmHg higher DBP in boys, with similar results observed in girls. Maternal hypertensive disorders of pregnancy were associated with 3.0 (0.1, 5.8) higher SBP, 3.17 (0.90, 5.44) mmHg higher DBP, 0.24 (0.01,0.47) mmol/L higher plasma glucose, and 0.26 (0.01,0.51) mmol/L higher serum triglycerides after adjustment for child age, sex, and ZWFL. Maternal hypertensive disorders of pregnancy and child overweight/obesity were associated with higher SBP and DBP at the age of 2 years
TMRT observations of 26 pulsars at 8.6 GHz
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio
Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities
and pulse width parameters of these pulsars are estimated. For eleven pulsars
these are the first high-frequency observations and for a further four, our
observations have a better signal-to-noise ratio than previous observations.
For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed
profiles. A comparison of 19 profiles with those at other frequencies shows
that in nine cases the separation between the outmost leading and trailing
components decreases with frequency, roughly in agreement with
radius-to-frequency mapping, whereas in the other ten the separation is nearly
constant. Different spectral indices of profile components lead to the
variation of integrated pulse profile shapes with frequency. In seven pulsars
with multi-component profiles, the spectral indices of the central components
are steeper than those of the outer components. For the 12 pulsars with
multi-component profiles in the high-frequency sample, we estimate the core
width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap
Characteristics of atmospheric compositions in the background area of Yangtze River delta during heavy air pollution episode
In order to understand the formation and evolution of recurrent severe haze pollution episodes in Yangtze River Delta, China, a short comparative sampling campaign was conducted at the Lin’an background monitoring station from 25 November 2013 to 14 December 2013. The characteristic concentrations of PM2.5, black carbon, CO2, CO, and CH4 have been systematically recorded at the abovementioned site. Coupled with detailed analysis of air backward trajectories, fire spot distribution surrounding the studied site and meteorological impacts, temporal trend, diurnal variation, and intercorrelation of the aforementioned species have also been comprehensively investigated throughout prehaze, haze, and posthaze periods
- …