Human Causes of Aeolian Desertification in Northern China

Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.

Expert consensus on the prevention and treatment of substance use and addictive behaviour-related disorders during the COVID-19 pandemic

In early 2020,the COVID-19 outbreak complicated the diagnosis,treatm ent and rehabilitation of patients with substance use disorders and increased the risks of substance abuse and addictive behaviours,such as online gaming disorders,in the general public.Substance use disorder is a chronic recurrent brain disease characterised by strong cravings,high recurrence rates,and a high proportion of comorbidity of mental and physical disorders.1 Therefore,regular long-term therapeutic interventions are critical to preventing dm g relapses while maintaining withdrawal.

Urinary Bladder Cancer: The Current and Potential Role of MR Imaging in Non-Distant Metastatic Lesions

Urinary bladder cancer is the second most common genitourinary malignancy in Westernized countries. A number of emerging imaging techniques have recently been reported in the literature for use in imaging bladder cancer. While the explicit application of MR imaging in bladder cancer especially in non-distant bladder cancer or bladder cancer localized in pelvic remains uncertain and awaits a thorough evaluation. Therefore, this article aims to make a systematic review of previous literature and provide a complete assessment of the value of MR as an evolving imaging tool in localized urinary bladder cancer application. Studies were conducted by searching the MEDLINE and PubMed databases up to 2012 using both medical subject heading (Mesh) and a free text method like “urinary bladder cancer”, “magnetic resonance imaging” or “MRI”, “diffusion weighted imaging” or “DWI”. About 53 articles were selected and analyzed which were considered to be associated with the objective of this systematic review (Table 1). Results showed that MRI especially the newer functional imaging technique like DWI may has a great potential role in localized bladder cancer like early detection, staging, evaluation of tumor aggressiveness and therapeutic responsiveness of patients in the assessment of urinary bladder cancer and so forth. Newer MRI has already proceeded promising results in bladder cancer application;and the explicit role of newer MRI in bladder cancer patients still needs further research and awaits to be thoroughly evaluated.

Anatomical feasibility of vagus nerve esophageal branch transfer to the phrenic nerve

This study measured the vagus and phrenic nerves from 12 adult cadavers. We found that the width and thickness of the vagus and phrenic nerves were different in the chest. The distance from the point of the vagus nerve and phrenic nerve on the plane of the inferior border of portal pulmonary arteries （T point） was approximately 7 cm to the diaphragm and was approximately 10 cm to the clavicle level. The number of motor fibers in the vagus nerves was 1 716 ± 362, and the number of nerve fibers was 4 473 ± 653. The number of motor fibers in the phrenic nerves ranged from 3 078 ± 684 to 4 794 ± 638, and the number of nerve fibers ranged from 3 437 ± 642 to 5 071 ± 723. No significant difference was found in the total number of nerve fibers. The results suggest that width, thickness, and total number of nerve fibers are similar between the vagus and phrenic nerves, but the number of motor fibers is different between them.

Engineered extracellular vesicles for delivery of siRNA promoting targeted repair of traumatic spinal cord injury

Spinal cord injury(SCI)is a severe disease of the nervous system that causes irreparable damage and loss of function,for which no effective treatments are available to date.Engineered extracellular vesicles(EVs)carrying therapeutic molecules hold promise as an alternative SCI therapy depending on the specific functionalized EVs and the appropriate engineering strategy.In this study,we demonstrated the design of a drug delivery system of peptide CAQK-modified,siRNA-loaded EVs(C-EVs-siRNA)for SCI-targeted therapy.The peptide CAQK was anchored through a chemical modification to the membranes of EVs isolated from induced neural stem cells(iNSCs).CCL2-siRNA was then loaded into the EVs through electroporation.The modified EVs still maintained the basic properties of EVs and showed favorable targeting and therapeutic effects in vitro and in vivo.C-EVs-siRNA specifically delivered siRNA to the SCI region and was taken up by target cells.C-EVs-siRNA used the inherent anti-inflammatory and neuroreparative functions of iNSCs-derived EVs in synergy with the loaded siRNA,thus enhancing the therapeutic effect against SCI.The combination of targeted modified EVs and siRNA effectively regulated the microenvironmental disturbance after SCI,promoted the transformation of microglia/macrophages from M1 to M2 and limited the negative effects of the inflammatory response and neuronal injury on functional recovery in mice after SCI.Thus,engineered EVs are a potentially feasible and efficacious treatment for SCI,and may also be used to develop targeted treatments for other diseases.

树种菌根类型通过细根生物量和凋落物动态影响土壤呼吸和土壤碳储存

热带森林是高生产力但同时也是脆弱的生态系统之一。一些全球范围的造林项目计划未来十年在热带地区种植数百万棵树。树种菌根类型影响森林土壤碳储存已成为共识,但在热带地区,树种菌根类型如何影响土壤呼吸(Rs)和碳储存,目前仍知之甚少。为研究树种菌根类型对Rs和土壤碳储存的影响,本实验在一个近30年热带同质园的3种丛枝菌根(AM)树种和3种外生菌根(EM)树种的单种林中,测量了其Rs和表层20 cm的碳含量,以及有关的生物因子(如根生物量、凋落物动态、土壤微生物)和非生物因子(如微气候)。研究结果表明,AM单种林的Rs、土壤碳含量,以及凋落物周转速率和细根生物量显著高于EM单种林。分析表明,与其他生物和非生物因子比较,树种菌根类型对Rs和土壤碳含量的影响最大。进一步分析表明,菌根类型是通过细根生物量和凋落物动态(凋落物产量、凋落物现存量、凋落物周转速率)直接和间接影响Rs和土壤碳含量。本研究结果强调了树种菌根类型对森林碳循环的影响,表明在热带地区种植AM树种可能比种植EM树种更能促进土壤固碳。

Conditional inversion to estimate parameters from eddy-flux observations

Aims Data assimilation is a useful tool to extract information from large datasets of the net ecosystem exchange(NEE)of CO_(2) obtained by eddy-flux measurements.However,the number of parameters in ecosystem models that can be constrained by eddy-flux data is limited by conventional inverse analysis that estimates parameter values based on one-time inversion.This study aimed to improve data assimilation to increase the number of constrained parameters.Methods In this study,we developed conditional Bayesian inversion to maximize the number of parameters to be constrained by NEE data in several steps.In each step,we conducted a Bayesian inversion to constrain parameters.The maximum likelihood estimates of the constrained parameters were then used as prior to fix parameter values in the next step of inversion.The conditional inversion was repeated until there were no more parameters that could be further constrained.We applied the conditional inversion to hourly NEE data from Harvard Forest with a physiologically based ecosystem model.Important Findings Results showed that the conventional inversion method constrained 6 of 16 parameters in the model while the conditional inversion method constrained 13 parameters after six steps.The cost function that indicates mismatch between the modeled and observed data decreased with each step of conditional Bayesian inversion.The Bayesian information criterion also decreased,suggesting reduced information loss with each step of conditional Bayesian inversion.A wavelet analysis reflected that model performance under conditional Bayesian inversion was better than that under conventional inversion at multiple time scales,except for seasonal and half-yearly scales.In addition,our analysis also demonstrated that parameter convergence in a subsequent step of the conditional inversion depended on correlations with the parameters constrained in a previous step.Overall,the conditional Bayesian inversion substantially increased the number of parameters to be constrained by NEE data and can be a powerful tool to be used in data assimilation in ecology.

Inverse analysis of coupled carbon-nitrogen cycles against multiple datasets at ambient and elevated CO_(2)

Aims Carbon(C)sequestration in terrestrial ecosystems is strongly regulated by nitrogen(N)processes.However,key parameters that determine the degree of N regulation on terrestrial C sequestration have not been well quantified.Methods Here,we used a Bayesian probabilistic inversion approach to estimate 14 target parameters related to ecosystem C and N interactions from 19 datasets obtained from Duke Forests under ambient and elevated carbon dioxide(CO_(2)).Important FindingsOur results indicated that 8 of the 14 target parameters,such as C:N ratios in most ecosystem compartments,plant N uptake and external N input,were well constrained by available datasets whereas the others,such as N allocation coefficients,N loss and the initial value of mineral N pool were poorly constrained.Our analysis showed that elevated CO_(2)led to the increases in C:N ratios in foliage,fine roots and litter.Moreover,elevated CO_(2)stimulated plant N uptake and increased ecosystem N capital in Duke Forests by 25.2 and 8.5%,respectively.In addition,elevated CO_(2)resulted in the decrease of C exit rates(i.e.increases in C residence times)in foliage,woody biomass,structural litter and passive soil organic matter,but the increase of C exit rate in fine roots.Our results demonstrated that CO_(2)enrichment substantially altered key parameters in determining terrestrial C and N interactions,which have profound implications for model improvement and predictions of future C sequestration in terrestrial ecosystems in response to global change.