Shaanxi Science and Technology Department

A robust, self-healing superhydrophobic poly(ethylene terephthalate) (PET) fabric was fabricated by a convenient solution-dipping method using an easily available material system consisting of polydimethylsiloxane and octadecylamine (ODA). The surface roughness was formed by self-roughening of ODA coating on PET fibers without any lithography steps or adding any nanomaterials. The fabric coating was durable to withstand 120 cycles of laundry and 5000 cycles of abrasion without apparently changing the superhydrophobicity. More interestingly, the fabric can restore its super liquid-repellent property by 72 h at room temperature even after 20000 cycles of abrasion. Meanwhile, after being damaged chemically, the fabric can restore its superhydrophobicity automatically in 12 h at room temperature or by a short-time heating treatment. We envision that this simple but effective coating system may lead to the development of robust protective clothing for various applications.

With the proliferation of versatile mobile applications, offloading compute-intensive tasks to the MEC/Cloud becomes a dramatic technique due to the limited resources and high user experience requirements at mobile devices. However, most existing works design their task offloading schemes without considering the dependence of tasks and the orchestration of the MEC and Cloud, and thus may limit the system performance. In this paper, we propose a dependent task offloading framework for multiple mobile applications, named COFE, where mobile devices can offload their compute-intensive tasks with dependent constraints to the MEC-Cloud system. It can assign the offloaded tasks to the MEC and Cloud adaptively to improve the user experience. Based on COFE, we formulate the task offloading problem as an average makespan minimization problem, which is proved to be NP-hard. Then, we propose a heuristic ranking-based algorithm to assign the offloaded tasks according to their bottom levels. Theoretical analysis proves the stability of the system under the proposed algorithm and extensive simulations validate that the proposed algorithm can significantly reduce the average makespan and deadline violation probabilities of offloaded applications.

Abstract Organic carbon (OC) sequestration through soil aggregation is an important aspect of land use change/conversion (LUCC) influencing the terrestrial ecosystem C cycle, although little is known on the changes in aggregate dynamics and their contributions to OC accumulation after LUCC in regions with serious soil erosion. Therefore, bulk soil samples under four land uses (farmland and three vegetated soils converted from farmland 42 years ago: Robinia pseudoacacia [RP42yr], Caragana korshinskii [CK42yr], and abandoned land [AL42yr]) in the Loess Plateau, China, was collected, separated into seven aggregate size fractions, and examined for OC content. Farmland conversion into AL42yr, CK42yr, and RP42yr increased macroaggregate (>2 mm) and mesoaggregate (2–0.25 mm) proportions, mean weight diameter, and geometric mean diameter but decreased microaggregates (0.25–0.053 mm) amount. Bulk soil and aggregates OC content and stock varied with soil depth and land use types but were usually highest in RP42yr. Mesoaggregates contained higher OC content and stock than other aggregates at 0‐ to 20‐cm depth under all land uses. Increases in the OC stocks of mesoaggregates accounted for 46% and 85% of the increase in bulk soil OC stocks at 0‐ to 20‐ and 20‐ to 40‐cm depth, respectively. Thus, soil OC accumulation after LUCC is mainly due to increased OC stock within mesoaggregates, which is further attributed to increased mesoaggregate proportions. Overall, vegetation restoration promotes the physical protection of OC by increasing soil aggregation, being a management option to enhance the C sequestration potential in ecological fragile regions.

Abstract MXene, a highly regarded material, has garnered significant attention within the electromagnetic wave (EMW) absorption field. However, the practical application of MXene is limited in harsh environments. Herein, a magic technique strategy of intercalation growth nucleation engineering is employed to prepare multifunctional MXene‐based EMW absorption materials. By regularly introducing different metal ions between the layers of MXene, an ultrathin absorber can be achieved by annealing after reacting in specific positions. The synthesized MCFC‐69‐8 shows hydrophobicity properties and exhibits a large charge‐transfer resistance of 18112 Ω cm 2 with a low corrosion rate and corrosion rate, indicating a good anti‐corrosion property. Through applying a series of mathematical methods, MCFC‐69‐8 shows 25% relaxation polarization loss and 75% conduction loss, and its relaxation time is linked with the specific type of relaxation polarization loss, resulting in an effective absorption bandwidth (EAB) of 4.9 GHz with an ultra‐thin optimal matching thickness of 1.48 mm. Finally, an absorber is built using CST to attain an ultrabroad EAB covering 2–18 GHz. This engineering not only simplifies the intercalation process but also achieves a high‐performance and anti‐corrosion EMW absorber, providing a valuable perception for realizing thinner MXene‐based EMW absorbers in the future.

Abstract Carbon nanodots (C-dots) with ultrasmall size possessing large surface-to-volume ratio are expected to improve their performance in sensing and catalytic applications. Here, we present a simple strategy to synthesis ultrasmall C-dots using double-pulse femtosecond laser ablation in solution. The size of C-dots reaches minimum value of ∼1 nm when the delay between the pulses was approaching the electron-ion relaxation time. In this case, the mean sizes of C-dots in double-pulse ablation are even smaller than that obtained in single-pulse ablation with the same laser fluence due to the suppression of rarefaction wave by the shock wave created by the second pulse. Furthermore, abundant functional groups are created on the surface of C-dots in double-pulse ablation because of reheating the nascent ablated materials by the second pulse. These results demonstrate that the double-pulse technique is therefore an effective strategy beyond single-pulse ablation to synthesis ultrasmall C-dots with abundant surface functional groups as well as other nanoparticle for catalytic and sensing applications.

In the present paper, we investigated the effects of afforestation on nitrogen fractions and microbial communities. A total of 24 soil samples were collected from farmland (FL) and three afforested lands, namely Robinia pseudoacacia L (RP), Caragana korshinskii Kom (CK), and abandoned land (AL), which have been arable for the past 40 years. Quantitative PCR and Illumina sequencing of 16S rRNA genes were used to analyze soil bacterial abundance, diversity, and composition. Additionally, soil nitrogen (N) stocks and fractions were estimated. The results showed that soil N stock, N fractions, and bacterial abundance and diversity increased following afforestation. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla of soil bacterial compositions. Overall, soil bacterial compositions generally changed from Actinobacteria (Acidobacteria)-dominant to Proteobacteria-dominant following afforestation. Soil N fractions, especially for dissolved organic nitrogen (DON), were significantly correlated with most bacterial groups and bacterial diversity, while potential competitive interactions between Proteobacteria (order Rhizobiales) and Cyanobacteria were suggested. In contrast, nitrate nitrogen (NO3(-)-N) influenced soil bacterial compositions less than other N fractions. Therefore, the present study demonstrated that bacterial diversity and specific species respond to farmland-to-forest conversion and hence have the potential to affect N dynamic processes in the Loess Plateau.

Abstract Alkynols semi-hydrogenation is a critical industrial process as the product, alkenols, have extensive applications in chemistry and life sciences. However, this class of reactions is plagued by the use of high-pressure hydrogen, Pd-based catalysts, and low efficiency of the contemporary thermocatalytic process. Here, we report an electrocatalytic approach for selectively hydrogenating alkynols to alkenols under ambient conditions. For representative 2-methyl-3-butene-2-ol, Cu nanoarrays derived electrochemically from CuO, achieve a high partial current density of 750 mA cm − 2 and specific selectivity of 97% at −0.88 V vs. reversible hydrogen electrode in alkaline solution. Even in a large two-electrode flow electrolyser, the Cu nanoarrays deliver a single-pass alkynol conversion of 93% with continuous production of 2-methyl-3-butene-2-ol at a rate of ~169 g g Cu − 1 h − 1 . Theoretical and in situ electrochemical infrared investigations reveal that the semi-hydrogenation performance is enhanced by exothermic alkynol adsorption and alkenol desorption on the Cu surfaces. Furthermore, this electrocatalytic semi-hydrogenation strategy is shown to be applicable to a variety of alkynol substrates.

BACKGROUND: The aim of this study was to investigate an association between birth defects and exposure to sulfur dioxide (SO2), nitrogen dioxide (NO2) and particles ≤10 μm in an aerodynamic diameter (PM10) during early pregnancy in Xi'an, China. METHODS: Birth defect data were from the Birth Defects Monitoring System of Xi'an, and data on ambient air pollutants during 2010-15 were from the Xi'an Environmental Protection Bureau. A generalized additive model (GAM) was used to investigate the relationship between birth defects and ambient air pollutants. RESULTS: Among the 8865 cases with birth defects analyzed, the overall incidence of birth defects was 117.33 per 10 000 infants. Ambient air pollutant exposure during the first trimester increased the risk of birth defects by 10.3% per 10 μg/m3 increment of NO2 and 3.4% per 10 μg/m3 increment of PM10. No significant association was found between birth defects and SO2. Moreover, NO2 increased risk of neural tube defects, congenital heart disease, congenital polydactyly, cleft palate, digestive system abnormalities and gastroschisis, and PM10 was associated with congenital heart disease and cleft lip with or without cleft palate. CONCLUSIONS: Chinese women should avoid exposure to high levels of NO2 and PM10 during the first 3 months of pregnancy.

The polishing activity of CeO2 abrasives is enhanced by improving the Ce3+ concentration on their surface. In this study, a series of Ce1–xLaxO2 abrasives with different La3+ doping were prepared. The abrasives were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The effects of La3+ doping on the morphology, size, and Ce3+ concentration of the abrasives were studied. The morphology of the particles changes from sphere to octahedron with the La3+ doping. The lattice expansion of the CeO2 crystal after La3+ doping also significantly improves the Ce3+ concentration on the abrasive surface. However, the Ce3+ concentration on the surface gradually became saturated when the x was 0.2 or more. The polishing performance proved that the material removal rate (MRR) is closely related to the Ce3+ concentration generated by La3+ doping. The MRR of pure CeO2 abrasives with a Ce3+ concentration of 20.53% on a SiO2 substrate is 59.31 nm/min, while the Ce0.7La0.3O2 abrasives with the Ce3+ concentration increased to 34.41% achieved 101.12 nm/min. The polished surface quality was characterized by atomic force microscopy, which shows improved roughness of all samples. Furthermore, the differences in the removal rate of Ce3+ and Ce4+ in CeO2-based abrasives on the SiO2 substrate were also discussed.

Abstract In order to solve the problems that boron nanoparticles (B NPs) are easy to agglomerate, low in combustion efficiency and difficult to ignite, 80 nm B NPs were doped with 50 nm aluminum nanoparticles (Al NPs) by electrospraying using 10 wt % PVDF as binders. The prepared B/PVDF/Al composite microspheres with diameter of 1∼5 μm were examined by scanning electron microscopy (SEM). Elemental maps confirmed the uniform distribution of B and Al NPs with the coating of polyvinylidene fluoride (PVDF). The thermal properties were tested by thermogravimetry‐differential scanning calorimetry (TG‐DSC), and the combustion process of samples in air was recorded by a high‐speed camera. The results showed that PVDF can reacted with the oxide layer on the surface of Al (Al 2 O 3 ) and B (B 2 O 3 ) NPs to promote the combustion and energy release of B/PVDF/Al. In addition, the thermal reactivity of B/PVDF/Al increased as the Al NPs content increases. Al NPs could reduce the ignition energy of B/PVDF/Al, allowing it to burn stably in air. A thermal reaction mechanism was proposed to explain qualitatively the four‐stage pattern of B/PVDF/Al decomposition observed in TG‐DSC curves.

Superhydrophobic surfaces on PET textiles were fabricated by combined bioinspiration from the strong adhesion of marine mussels and the two-scale structure of lotus leaves under mild conditions. Dopamine can spontaneously polymerize in alkaline aqueous solution to form a thin adhesive layer of polydopamine (PDA) wrapping on the micro-scale fibers. The as-formed thin PDA layer worked as a reactive template to generate PDA nanoparticles decorated on the fiber surfaces, imparting the textiles with excellent UV-shielding properties as well as a hierarchical structure similar to the morphology of the lotus leaf. After further modification with perfluorodecyl trichlorosilane, the textiles turned superhydrophobic with a water contact angle higher than 150°. Due to the strong adhesion of PDA to a wide range of materials, the present strategy may be extendable to fabrication of superhydrophobic surfaces on a variety of other substrates.

Gentiana macrophylla is a perennial herb in the Gentianaceae family, whose dried roots are used in traditional Chinese medicine. Here, we assembled a chromosome-level genome of G. macrophylla using a combination of Nanopore, Illumina, and Hi-C scaffolding approaches. The final genome size was ~1.79 Gb (contig N50 = 720.804 kb), and 98.89% of the genome sequences were anchored on 13 pseudochromosomes (scaffold N50 = 122.73 Mb). The genome contained 55,337 protein-coding genes, and 73.47% of the assemblies were repetitive sequences. Genome evolution analysis indicated that G. macrophylla underwent two rounds of whole-genome duplication after the core eudicot γ genome triplication event. We further identified candidate genes related to the biosynthesis of iridoids, and the corresponding gene families mostly expanded in G. macrophylla. In addition, we found that root-specific genes are enriched in pathways involved in defense responses, which may greatly improve the biological adaptability of G. macrophylla. Phylogenomic analyses showed a sister relationship of asterids and rosids, and all Gentianales species formed a monophyletic group. Our study contributes to the understanding of genome evolution and active component biosynthesis in G. macrophylla and provides important genomic resource for the genetic improvement and breeding of G. macrophylla.

BACKGROUND: Childhood undernutrition adversely impacts child health and is one of China's largest health burdens. However, there is limited information on the current rate of childhood undernutrition in rural Western China. The purpose of this study was to investigate the prevalence of childhood undernutrition and explore its association with socio-economic characteristics in Western China. METHODS: A total of 13,532 children of 0 ~ 36 months of age were recruited as subjects from 45 counties and 10 provinces in Western China with a 3-stage probability proportion to size sampling. The composite index of anthropometric failure (CIAF) was used to assess the childhood undernutrition. The association between socio-economic characteristics and childhood undernutrition was analyzed using a two-level logistic regression. RESULTS: Based on CIAF, the prevalence of undernutrition among children under three years of age in rural Western China in 2005 was 21.7%. The two-level logistic analysis presented a large difference in undernutrition among the 10 provinces with the highest odds ratio in Guizhou (OR: 2.15, 95%CI: 1.50, 3.08). Older children had a higher prevalence of undernutrition. As compared to girls, boys were more likely to be undernourished (OR 1.27, 95% CI: 1.16, 1.39). The likelihood of undernutrition was lower in subjects of Han ethnicity as opposed to subjects of minority ethnicities (OR 0.77, 95%CI: 0.65, 0.90). In addition, the education levels of the mother as well as wealth index were both negatively associated with childhood undernutrition. CONCLUSIONS: Childhood undernutrition still remains a large health challenge in rural Western China. This study has important policy implications for the Chinese government to improve childhood undernutrition in the surveyed areas.

Passive daytime radiative cooling without any energy input has attracted significant attention due to its ability to spontaneously radiate heat into cold outer spaces. However, the distinctive structure and optical properties made radiative cooling materials white in appearance, which limits their use in actual application. In this study, poly(dimethylsiloxane) (PDMS), poly(ethyl cyanoacrylate) (PECA), polystyrene (PS), and pigments that selectively absorb visible light with high emissivity were adopted to fabricate a colored superhydrophobic radiative cooling coating through spraying and nonsolvent-induced phase separation. The as-fabricated yellow, red, and green PS/PDMS/PECA composite coatings exhibited high solar reflectivities of 92.8, 89.8, and 86.6% with strong infrared emissivities of 95.4, 95.3, and 96.3%, respectively, which correspondingly realized a subambient temperature reduction of 5.3, 3.5, and 2.5 °C. The self-cleaning property of the coating caused by superhydrophobicity helps protect the coating from contamination, favoring a stable outdoor cooling performance. Additionally, the composite coating was resistant to different chemical immersions, ultraviolet (UV) irradiation, sand impact, water impact, and sandpaper abrasion, which might improve the applicability of the material and promote the cooling materials toward large-area production for practical application.

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology with a high rate of disability. Traditional treatments for RA remain a challenging issue. For example, nonsteroidal anti-inflammatory drugs (NSAIDs) have no therapeutic effects on joint destruction, and the prominent side effects include gastrointestinal symptoms. RA is characterized by recurrence and bone attrition. Therefore, regenerative medicine and the use of umbilical cord mesenchymal stem cell (UC-MSC) therapies have recently emerged as potential options. UC-MSCs are multifunctional stem cells that are present in neonatal umbilical cord tissue and can differentiate into many kinds of cells, which have broad clinical application prospects in the tissue engineering of bone, cartilage, muscle, tendon, ligament, nerve, liver, endothelium, and myocardium. Moreover, UC-MSCs have advantages, such as convenient collection of materials and no ethical disputes; thus, these cells have attracted increasing attention from researchers. However, there are few clinical studies regarding UC-MSC therapy for RA. In this paper, we will review traditional drugs for RA treatment and then focus on UC-MSC therapy for RA, including preclinical and clinical UC-MSC applications for RA patients in the context of regenerative medicine. Finally, we will summarize the challenges and perspectives of UC-MSCs as a potential therapeutic strategy for RA. This review will help to design and discover more potent and efficacious treatments for RA patients and aid in advancing this class of cell therapy.

Herein, a better mesophase pitch as precursor for the manufacturing of green needle coke is obtained by a new process, whereas the refined medium‐ and low‐temperature coal tar pitch (RCTP) is obtained by a solvent sedimentation method, and then, it is co‐carbonized with coal‐based hydrogenated diesel oil at 420 °C for 6 h. The mesophase pitch structure is characterized by a polarized light optical microscope, Fourier transform IR (FT‐IR) spectroscopy, and 1 H nuclear magnetic resonance (NMR). The results indicate that the aromatic hydrogen content of mesophase pitch gradually increases, as the carbonization temperature increases. Also, the mesophase pitch with aliphatic side chain substitution (CH 3 and CH 2 ) is obtained at 420 °C for 2 h, which is conducive for polyaromatic hydrocarbon to the orderly accumulation. It is also a basis for preparing better green needle coke. The polarized light analysis results propose that the mesophase with a wide‐area streamlined structure is obtained at a constant temperature of 420 °C for 6 h, whose temperature and soaking time are lower than that of the high‐temperature coal tar pitch and petroleum pitch for preparing the mesophase pitch. Also, the better direction and order fiber of green needle coke with 53 % fiber are acquired.

Cross-project defect prediction (CPDP) refers to recognizing defective software modules in one project (i.e., target) using historical data collected from other projects (i.e., source), which can help developers find defects and prioritize their testing efforts. Unfortunately, there often exists large distribution difference between the source and target data. Most CPDP methods neglect to select the appropriate source data for a given target at the project level. More importantly, existing CPDP models are parametric methods, which usually require intensive parameter selection and tuning to achieve better prediction performance. This would hinder wide applicability of CPDP in practice. Moreover, most CPDP methods do not address the cross-project class imbalance problem. These limitations lead to suboptimal CPDP results. In this paper, we propose a novel data selection and sampling based domain programming predictor (DSSDPP) for CPDP, which addresses the above limitations. DSSDPP is a non-parametric CPDP method, which can perform knowledge transfer across projects without the need for parameter selection and tuning. By exploiting the structures of source and target data, DSSDPP can learn a discriminative transfer classifier for identifying defects of the target project. Extensive experiments on 22 projects from four datasets indicate that DSSDPP achieves better <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MCC</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AUC</i> results against a range of competing methods both in the single-source and multi-source scenarios. Since DSSDPP is easy, effective, extensible, and efficient, we suggest that future work can use it with the well-chosen source data to conduct CPDP especially for the projects with limited computational budget.

Abstract Stone coal, which has high ash yield, low carbon content, and low calorific value, releases toxic elements during the combustion process. In this study, samples were collected from an open-pit stone coal mine in the southern Shaanxi province, China. A simulated combustion experiment and sequential chemical extraction were applied to investigate the enrichment, occurrence, and release of Cr, Cd, and Pb in raw stone coal and ash. The contents of Cr, Cd, and Pb in raw stone coal were larger than those reported for other coals in China and worldwide. The enrichment factors of Cr, Cd, and Pb in ash at different temperatures exceeded 0.7, with the exception of Cd at 1000 °C. This indicates that Cr, Cd, and Pb were first enriched at low temperature (below 600 °C) and then volatilized at high temperature due to the decomposition of clay minerals. The dominant forms of toxic elements in raw stone coal were Fe–Mn-bound Cr and Cd and carbonates of Pb. As the temperature increased, the organic forms decreased obviously, and the residual forms increased; however, the Fe–Mn-bound forms remained the dominant forms of Cr, Cd, and Pb.

BACKGROUND: The objective of this study was to determine the relationship between the quality of feeding practices and children's nutritional status in rural western China. METHODS: A sample of 12,146 pairs of 6- to 35-month-old children and their mothers were recruited using stratified multistage cluster random sampling in rural western China. Quantile regression was used to analyze the relationship between the Infant and Child Feeding Index (ICFI) and children's nutritional status. RESULTS: In rural western China, 24.37% of all infants and young children suffer from malnutrition. Of this total, 19.57%, 8.74% and 4.63% of infants and children are classified as stunting, underweight and wasting, respectively. After adjusting for covariates, the quantile regression results suggested that qualified ICFI (ICFI > 13.8) was associated with all length and HAZ quantiles (P<0.05) and had a greater effect on the following: poor length and HAZ, the β-estimates (length) from 0.76 cm (95% CI: 0.53 to 0.99 cm) to 0.34 cm (95% CI: 0.09 to 0.59 cm) and the β-estimates (HAZ) from 0.17 (95% CI: 0.10 to 0.24) to 0.11 (95% CI: 0.04 to 0.19). Qualified ICFI was also associated with most weight quantiles (P<0.05 except the 80th and 90th quantiles) and poor and intermediate WAZ quantiles (P<0.05 including the 10th, 20th 30th and 40th quantiles). Additionally, qualified ICFI had a greater effect on poor weight and WAZ quantiles in which the β-estimates (weight) were from 0.20 kg (95% CI: 0.14 to 0.26 kg) to 0.06 kg (95% CI: 0.00 to 0.12 kg) and the β-estimates (WAZ) were from 0.14 (95% CI: 0.08 to 0.21) to 0.05 (95% CI: 0.01 to 0.10). CONCLUSIONS: Feeding practices were associated with the physical development of infants and young children, and proper feeding practices had a greater effect on poor physical development in infants and young children. For mothers in rural western China, proper guidelines and messaging on complementary feeding practices are necessary.

Utility tunnel is a kind of underground tunnel structure that carries more than two types of public utility lines, and the utility tunnels built by the prefabricated method have been adopted in many modern cities due to their easy maintenance and environmental protection capabilities. However, knowledge about the seismic performance of the prefabricated utility tunnel and pipelines inside is quite limited. In this paper, a prefabricated utility tunnel newly built in Xi’an, China, is taken as the prototype; a series of shaking table tests are conducted to investigate the seismic performance of the prefabricated utility tunnel in loess foundation, using El Centro earthquake wave as the input loading. Details of the experimental setup focus on the design of the soil container, scaled model (1 : 10), sensor arrangement, and test cases. Dynamic responses including evaluation of boundary effect, the amplification factor of the ground and structure, distribution of soil pressure, characteristics of predominant frequencies, and the damage phenomena are analyzed. Dynamic strain obtained by Fiber Bragg Grating sensors releases the critical positions of the prefabricated utility tunnel during the earthquake. Moreover, the dynamic responses of the pipelines contained in the utility tunnel are also analyzed. From aforementioned results, the seismic performance of the prefabricated utility tunnel has been revealed. The results will provide a reference for the seismic design of prefabricated utility tunnels.