Motivated by attributes including environmental hazards and resource value, the recycling of the spent graphite has aroused increasing attention. Meanwhile, a silicon/graphite composite has been ...considered as a promising high-capacity anode for lithium-ion batteries. However, uniform dispersion and outperformed stability of silicon (Si) particles in the graphite matrix still remain a great challenge. Current solutions mainly focus on the design of Si nanostructures and the overall architecture of the silicon/graphite composite, while little attention has been paid to the graphite matrix. Herein, the Si/spent graphite (Si/SG) composite was prepared based on the recycling of SG. The SG was
in situ
modified during the battery cycling process and formed unique physicochemical properties. By spontaneously tuning the zeta potential, the electrostatic force integrated the Si nanoparticles within the SG matrix to restrain the volume strain upon lithiation/delithiation. Besides, defect-enriched and exfoliated SG can effectively enhance the electric conductivity, facilitating the electrochemical kinetics in the electrodes. What is more, the oxygen-containing functional groups on the SG could adjust the solid electrolyte interphase (SEI) component by generating more organic components to improve the mechanical toughness of the SEI layer. Consequently, the Si/SG composite electrode delivers a high initial discharge capacity of 1321.8 mA h g
−1
at 0.05 A g
−1
and stable cycle life with a capacity retention of 69% at 1 A g
−1
after 400 cycles. The proposed composite may provide some guidelines for improving the interface stability of the Si/graphite anode and simultaneously the high-value application of spent graphite.
A silicon/graphite composite anode with constrained swelling and a stable SEI was developed, utilizing the intrinsic merits of the spent graphite.
Dietary exposure of cadmium (Cd) has not been studied in Southwest China. The objective of the study was to determine the pollution characteristics and contamination levels in various agriculture ...products in Southwest China and to conduct a comparison of dietary exposure assessment of Cd in polluted and non-polluted areas. Results showed that the mean Cd contents in rice were 0.53 and 0.52 mg/kg in the high-polluted and low-polluted areas, respectively, with the average value was 0.03 mg/kg in the control area. The mean dietary Cd exposure from rice and vegetables of the selected non-occupational residents in Southwest China was 113.10 μg/kg bodyweight (bw)/month, 88.80 μg/kg bw/month, and 16.50 μg/kg bw/month in the high-polluted, low-polluted, and control areas, respectively, which correspond to 4.5 times, 3.6 times, and 0.66 times of the provisional tolerable monthly intake (25 μg/kg bw/month) established by the Joint FAO/WHO Expert Committee on Food Additives. The findings indicated that the risk for Cd exposure of residents was high due to home-grown food (most especially rice) being near polluted areas and is of great concern.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
This study analyzes the large-scale circulation associated with the tropical cyclones (TCs) affecting the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) in southern China during the peak ...TC season (July–September) from 1980 to 2019. The results show that the frequency of the TCs affecting the GBA is closely tied to a meridional Rossby wave train from Southeast Asia to Northeast Asia, manifested by the important roles of the variability of the monsoon trough (MT) and the western North Pacific subtropical high (WNPSH). In the active GBA TC years, intensified and westward-shifted MT and northeastward-shrunk WNPSH cause anomalous southeasterly wind over the southeast coast of China, and hence more TCs move northwestward to the GBA. Furthermore, the cyclonic convergent conditions related to the tacit-and-mutual configurations of MT and WNPSH favor more TC genesis in the west of 140° E over the WNP via significant larger meridional shear vorticity of the zonal winds, ascending motions, and positive vorticity. Opposite features of wind anomalies and TC genesis are seen in the inactive GBA TC years. Both statistical and numerical analyses confirm that the meridional Rossby wave train is associated with a Matsuno–Gill response to the anomalous convective activity over the western Pacific warm pool, which is maintained by the ascending branches of the La Niña-type Walker circulation over the Pacific and the monsoon-enhanced Walker circulation over the Indian Ocean.
Simple and inexpensive polyhalides (CCl4 and C2Cl6) have been found to be effective and versatile oxidants in removing electrons from Breslow intermediates under N‐heterocyclic carbene (NHC) ...catalysis. This oxidative reaction involves multiple single‐electron‐transfer (SET) processes and several radical intermediates. The α, β, and γ‐carbon atoms of aldehydes and enals could be readily functionalized. Given the low cost of the oxidants and the broad applicability of the reactions, this study is expected to greatly enhance the feasibility of oxidative NHC catalysis for large‐scale applications. Also this new SET radical process with polyhalides as single‐electron oxidants will open a new avenue in the development of NHC‐catalyzed radical reactions.
Simple and inexpensive polyhalides (e.g., C2Cl6) can be used as effective oxidants in N‐heterocyclic carbene (NHC) organocatalysis. This approach allows oxidation of an aldehyde‐derived Breslow intermediate into an acyl azolium intermediate involving multiple single‐electron‐transfer (SET) processes. The α‐, β‐, and γ‐carbon atoms of aldehydes could be readily functionalized with this method.
Tuberculosis (TB) remains a serious global public health problem in the present. TB also affects other sites (extrapulmonary tuberculosis, EPTB), and accounts for a significant proportion of ...tuberculosis cases worldwide. In order to comprehensively understand epidemiology of EBTB in China, and improve early diagnosis and treatment, we conducted a large-scale multi-center observational study to assess the demographic data and the prevalence of common EPTB inpatients, and further evaluate the prevalence of EPTB concurrent with Pulmonary tuberculosis (PTB) and the associations between multiple EPTB types and gender-age group in China. All consecutive agegreater than or equal to15yr inpatients with a confirmed diagnosis of EPTB during the period from January 2011 to December 2017 were included in the study. The descriptive statistical analysis included median and quartile measurements for continuous variables, and frequencies and proportions with 95% confidence intervals (CIs) for categorical variables. Multinomial logistic regression analysis was used to compare the association of multiple EPTB types between age group and gender. The results showed that the proportion of 15-24 years and 25-34 years in EPTB inpatients were the most and the ratio of male: female was 1.51. Approximately 70% of EPTB inpatients were concurrent with PTB or other types of EPTB. The most common of EPTB was tuberculous pleurisy (50.15%), followed by bronchial tuberculosis (14.96%), tuberculous lymphadenitis of the neck (7.24%), tuberculous meningitis (7.23%), etc. It was found that many EPTB inpatients concurrent with PTB. The highest prevalence of EPTB concurrent with PTB was pharyngeal/laryngeal tuberculosis (91.31%), followed by bronchial tuberculosis (89.52%), tuberculosis of hilar lymph nodes (79.52%), tuberculosis of mediastinal lymph nodes (79.13%), intestinal tuberculosis (72.04%), tuberculous pleurisy (65.31%) and tuberculous meningitis (62.64%), etc. The results from EPTB concurrent with PTB suggested that females EPTB inpatients were less likely to be at higher risk of concurrent PTB (aOR = 0.819, 95%CI:0.803-0.835) after adjusted by age. As age increasing, the trend risk of concurrent PTB decreased (aOR = 0.994, 95%CI: 0.989-0.999) after adjusted by gender. Our study demonstrated that the common EPTB were tuberculous pleurisy, bronchial tuberculosis, tuberculous lymphadenitis of the neck, tuberculous meningitis, etc. A majority of patients with pharyngeal/laryngeal tuberculosis, bronchial tuberculosis, tuberculosis of hilar/mediastinal lymph nodes, intestinal tuberculosis, tuberculous pleurisy, tuberculous meningitis, etc. were concurrent with PTB. Female EPTB inpatients were less likely to be at higher risk of concurrent PTB, and as age increasing, the trend risk of concurrent PTB decreased. The clinicians should be alert to the presence of concurrent tuberculosis in EPTB, and all suspected cases of EPTB should be assessed for concomitant PTB to determine whether the case is infectious and to help for early diagnosis and treatment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The mechanisms of bifurcation, a key step in thyroid development, are largely unknown. Here we find three zebrafish lines from a forward genetic screening with similar thyroid dysgenesis phenotypes ...and identify a stop-gain mutation in hgfa and two missense mutations in met by positional cloning from these zebrafish lines. The elongation of the thyroid primordium along the pharyngeal midline was dramatically disrupted in these zebrafish lines carrying a mutation in hgfa or met. Further studies show that MAPK inhibitor U0126 could mimic thyroid dysgenesis in zebrafish, and the phenotypes are rescued by overexpression of constitutively active MEK or Snail, downstream molecules of the HGF/Met pathway, in thyrocytes. Moreover, HGF promotes thyrocyte migration, which is probably mediated by downregulation of E-cadherin expression. The delayed bifurcation of the thyroid primordium is also observed in thyroid-specific Met knockout mice. Together, our findings reveal that HGF/Met is indispensable for the bifurcation of the thyroid primordium during thyroid development mediated by downregulation of E-cadherin in thyrocytes via MAPK-snail pathway.
Male infertility is a global public health issue recognized by the WHO. Recently, antioxidants are increasingly used to treat idiopathic male infertility. However, the lack of available evidence has ...led to the inability to rank the effects of antioxidants on the sperm quality parameters and pregnancy rate of infertile men. This network meta-analysis studied the effects of different antioxidants on the sperm quality and pregnancy rate of idiopathic male infertility.
We searched PubMed, Embase, Web of Science, and Cochrane Library databases for randomized controlled trials (RCTs). The weighted mean difference (WMD) and odds ratio (OR) were applied for the comparison of continuous and dichotomous variables, respectively, with 95% CIs. The outcomes were sperm motility, sperm concentration, sperm morphology, and pregnancy rate.
A total of 23 RCTs with 1,917 patients and 10 kids of antioxidants were included. l-Carnitine, l-carnitine+l-acetylcarnitine, coenzyme-Q10, ω-3 fatty acid, and selenium were more efficacious than placebo in sperm quality parameters. l-Carnitine was ranked first in sperm motility and sperm morphology (WMD 6.52% 95% CI: 2.55% to 10.05%, WMD 4.96% 0.20% to 9.73%). ω-3 fatty acid was ranked first in sperm concentration (WMD 9.89 × 10
/ml, 95% CI: 7.01 to 12.77 × 10
/ml). In terms of pregnancy rate, there was no significant effect as compared with placebo.
l-Carnitine was ranked first in sperm motility and sperm morphology. ω-3 fatty acid was ranked first in sperm concentration. Coenzyme-Q10 had better effective treatment on sperm motility and concentration. Furthermore, high-quality RCTs with adequate sample sizes should be conducted to compare the outcomes of different antioxidants.
It is well known that global warming increases the atmospheric water vapor content, which results in substantial changes in the hydrological cycle. Using five observational data sets, the results ...show that an increasing trend of near‐surface water vapor pressure (AVP) over land and ocean was significant from 1975 to 1998, while such an increasing trend in AVP subsequently weakened from 1999 to 2019. This phenomenon is associated with decreased oceanic evaporation and land surface evapotranspiration in response to recent climate variations. One consequence of such a phenomenon is a large increase in near‐surface vapor pressure deficit (VPD), which in turn increases atmospheric demand for water vapor and thus aridity and drought over land. This result emphasizes the importance of water vapor change under global warming.
Plain Language Summary
As one of the key components of the atmosphere, water vapor plays a crucial role in regulating the processes in the climate system. It has long been established that water vapor generally increases with global rising mean air temperature as dictated by the Clausius‐Clapeyron theorem if relative humidity changes little. Here, we use five observational data sets to study the trend changes in near‐surface actual water vapor pressure (AVP) from 1975 to 2019. Our results show an increasing trend of global land and ocean AVP from 1975 to 1998, but the increasing trend has weakened since the late 1990s. This phenomenon in water vapor is associated with decreased oceanic evaporation and land surface evapotranspiration. This phenomenon further enhances the atmospheric vapor pressure deficit (VPD), which dominates the water and carbon cycling in the terrestrial ecosystem by regulating vegetation stomatal conductance.
Key Points
The increasing trend of near‐surface actual water vapor pressure (AVP) over land and ocean has weakened since the end of the 1990s
The weakened water vapor pressure increase is associated with decreased oceanic evaporation and land surface evapotranspiration
One consequence of the weakened water vapor pressure increase is a large increase in near‐surface vapor pressure deficit
The foundation of intelligent collaborative control of a shearer, scraper conveyor, and hydraulic support (three-machines) is to achieve the precise perception of the status of the three-machines and ...the full integration of information between the equipment. In order to solve the problems of information isolation and non-flow, independence between equipment, and weak cooperation of three-machines due to an insufficient fusion of perception data, a fusion method of the equipment’s state perception system on the intelligent working surface was proposed. Firstly, an intelligent perception system for the state of the three-machines in the working face was established based on fiber optic sensing technology and inertial navigation technology. Then, the datum coordinate system is created on the working surface to uniformly describe the status of the three-machines and the spatial position relationship between the three-machines is established using a scraper conveyor as a bridge so that the three-machines become a mutually restricted and collaborative equipment system. Finally, an indoor test was carried out to verify the relational model of the spatial position of the three-machines. The results indicate that the intelligent working face three-machines perception system based on fiber optic sensing technology and inertial navigation technology can achieve the fusion of monitoring data and unified expression of equipment status. The research results provide an important reference for building an intelligent perception, intelligent decision-making, and automatic execution system for coal mines.
Single-crystal Ni-rich cathodes possess prominent structural integrity and thermal stability compared to their poly-crystal counterparts, yet their application at high voltage is hampered by the ...intragranular cracks that remain intractable for mitigation. Herein, a novel niobium-modified single-crystal LiNi
0.83
Co
0.12
Mn
0.05
O
2
(NCM) cathode, which integrates grain size and lattice regulation superiorities, is designed. The results demonstrate that doped Nb
5+
reduces the surface energies of (001), (012), and (104) faces, followed by the diminution of critical nuclei size and grain size based on the classical nucleation theory. Smaller grain size effectively facilitates the release of internal strain, resulting in fewer planar slips and intragranular cracks inside the niobium-modified cathodes. Moreover, a heterogeneous surface structure derived by Nb
5+
doping acts as a shield to alleviate the deleterious interfacial phase transition. Under a high-voltage of 4.4 V, the 0.5 mol% Nb
5+
-doped NCM displays an outstanding discharge capacity (211.3 mA h g
−1
) at 0.1C, higher capacity retention (155.0 mA h g
−1
vs.
130.2 mA h g
−1
) at 1C after 100 cycles and a superior rate capacity (152.3 mA h g
−1
vs.
118.9 mA h g
−1
) at 5C in comparison with the pristine material. This bifunctional regulation strategy provides novel insights into the rational design of single-crystal Ni-rich cathodes.
Surface energy alteration-derived grain size regulation provides both high-quality grain integrity and remarkable cycling stability for single-crystal Ni-rich cathodes.
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