[Arsenic Methylation Efficiency Changes During Paddy Soil Drying and Its Key Influencing Factors Analysis].

The straight head disease of rice is one of the main problems limiting rice production. Arsenic (As) methylation in paddy soils is considered to be highly related to the occurrence of the straight head disease. As a typical field practice, rice fields are usually drained during the late tillering stage and the mid-late grain filling stage. Nevertheless, the key influencing factors on the As methylation efficiency during paddy soil drying remain unclear. In this study, an indoor cultivation experiment was set up to simulate the drying process of paddy soil. Two As-contaminated soils collected from Xingren (XR) in Guizhou province and Nandan (ND) in Guangxi province were used as test soils. Each soil was treated with the addition of rice straw (RS) and without rice straw (CK). With the drying of paddy soil (0, 24, 36, 48, and 60 h), the changes in soil Eh, pH, total organic carbon (TOC), and As chemical species in the porewater were determined. The abundance of the As methylation functional gene (arsM), sulfate-reducing bacteria (harboring dsrA, As methylation-related microorganism), and methanogens (harboring mcrA, As demethylation-related microorganism), as well as the diversity of arsM-harboring microorganisms, were also observed. The results showed that during the process of drying paddy soil, soil Eh changed from -300--200 mV under complete flooding to -150--50 mV after drying; however, the change in soil pH was not obvious. The concentrations of inorganic As (iAs) and dimethylarsenic (DMAs) in porewater significantly increased (P<0.05) with the drying process. Additionally, the concentration of DMAs in the RS treatment was prominently higher than that in CK. Compared with XR soil, the concentration of DMAs in ND soil was higher. As a function of soil drying time, the As methylation efficiency of XR soil (XR-CK and XR-RS) slightly increased but was not significant (P>0.05), whereas the As methylation efficiency of ND soil (ND-CK and ND-RS) increased significantly (P<0.05). After the drying time reached 60 h, the As methylation efficiency of ND-CK and ND-RS increased by 61.8% and 23.2%, respectively, compared with those at the early stage of drying (0 hours). The copy numbers of the arsM and dsrA genes greatly increased with the extension of drying time, whereas an opposite trend was observed for the copy number of the mcrA gene. Furthermore, the addition of straw obviously increased the gene abundance of whole bacteria and arsM-, dsrA-, and mcrA-harboring bacteria. Based on the multi-factor analysis of variance and the redundancy analysis, it was found that the test soil type, straw addition, drying time, and their interaction had a critical influence on the changes in As species, As methylation efficiency, and the gene abundance in soils. TOC, Eh, and the functional genes associated with As methylation were positively linked with the methylated As content in soil porewater but negatively correlated with that of iAs. According to the sequence of the arsM-harboring microbe, it was clearly demonstrated that a community shift of As-methylating microbe occurred with the soil drying. Here, the following conclusions were derived:① the drying process did not lower the As methylation efficiency in paddy soil. On the contrary, in this study, the As methylation efficiency, especially that for ND soil, remarkably improved. The addition of straw notably promoted the As methylation efficiency and the content of DMAs in porewater. ② An increasing tendency was observed for the abundance of microbes related to As methylation, whereas a reverse trend was indicated for microbes related to As demethylation. The community shift of arsM-harboring microbes might be the crucial reason for the improved As methylation efficiency during the soil drying. These observations contribute to a better understanding of the As methylation process during paddy soil drying and will shed light on the future mitigation of rice straight head disease in paddy soils.

Presentation of long COVID and associated risk factors in a mobile health study

BackgrounThe Covid Collab study was a citizen science mobile health research project set up in June 2020 to monitor COVID-19 symptoms and mental health through questionnaire self-reports and passive wearable device data. MethodsUsing mobile health data, we consider whether a participant is suffering from long COVID in two ways. Firstly, by whether the participant has a persistent change in a physiological signal commencing at a diagnosis of COVID-19 that last for at least twelve weeks. Secondly, by whether a participant has self-reported persistent symptoms for at least twelve weeks. We assess sociodemographic and wearable-based risk factors for the development of long COVID according to the above two categorisations. FindingsPersistent changes to physiological signals measured by commercial fitness wearables, including heart rate, sleep, and activity, are visible following a COVID-19 infection and may help differentiate people who develop long COVID. Anxiety and depression are significantly and persistently affected at a group level following a COVID-19 infection. We found the level of activity undertaken in the year prior to illness was protective against long COVID and that symptoms of depression before and during the acute illness may be a risk factor. InterpretationMobile health and wearable devices may prove to be a useful resource for tracking recovery and presence of long-term sequelae to COVID-19. Mental wellbeing is significantly negatively effected on average for an extended period of time following a COVID-19 infection.

Influence of straw-derived humic acid-like substance on the availability of Cd/As in paddy soil and their accumulation in rice grain.

Humic acid amendments have been widely advocated for the remediation of heavy metal-contaminated soil. However, the impacts of straw-derived humic acid-like substances on the remediation of cadmium (Cd) and arsenic (As) co-contaminated paddy soil remain unclear and the potential mechanism required clarification. In this study, we employed a pot experiment and chose a straw-derived humic acid-like substance (BFA) as the amendment with four doses to investigate how BFA affects the availability of Cd and As in soil and their accumulation in rice. The results showed that grain Cd decreased by 25.65-36.03%, while there was no significant change in total As (TAs) with the addition of BFA. The contents of DCB-Fe, DCB-As and DCB-Cd on the root surface decreased by 6.07-40.54% during the whole growth stage. The addition of BFA significantly decreased the pe + pH and enhanced the transformation of crystalline iron oxides (Fed) into amorphous forms (Feo) in the soil. The CaCl2-extractable Cd decreased and the KH2PO4-extractable As increased with the decrease in pe + pH and Fed and the relative increase in Feo. The correlation analysis showed that the decrease in availability of Cd and translocation factor of Cd effectively decreased the grain Cd and the decrease in DCB-Cd may also contribute to decreasing the uptake of Cd by rice. However, the increase in As of roots and shoots might play key roles in restricting the transport of As to rice grains. Consequently, the addition of BFA could effectively reduce the Cd accumulation in rice under flooding conditions, while no risk of As accumulation in rice grain was observed. The present work provides a new perspective for the application of straw-derived humic acid-like substances as amendments on Cd-As co-contaminated soils, which should be advocated as an eco-friendly, economical and effective soil amendment in the future.

Prevalence and Risk Factors of Postdialysis Fatigue in Patients Under Maintenance Hemodialysis: A Systematic Review and Meta-Analysis

Purpose@#Despite the high prevalence of postdialysis fatigue (PDF) in maintenance hemodialysis patients, no meta-analysis on the prevalence and risk factors of PDF has yet been published. This study aimed to identify the prevalence of PDF and explore its related factors. @*Methods@#PubMed, Embase, CENTRAL, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the four Chinese databases (National Knowledge Infrastructure [CNKI], Chinese Biomedical Literature database [SinoMed], Wanfang Digital Periodicals [WANFANG], and Chinese Science and Technology Periodicals [VIP] database) were searched from inception up to July 2022. This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The articles were independently searched by two reviewers, and the relevant data were extracted. The Agency for Healthcare Research and Quality was used to assess the quality of the included studies. @*Results@#Thirteen articles with 2,118 participants were included. The pooled prevalence was 60.0%. The meta-analysis results revealed that the ultrafiltration volume, mean arterial pressure after dialysis, and good sleep quality were potentially associated with PDF, whereas only good sleep quality (odds ratio 0.24, 95% confidence interval 0.19e0.30) was significantly associated with PDF. @*Conclusion@#PDF is common in maintenance hemodialysis patients, which is related to the ultrafiltration volume, sleep quality, and mean arterial pressure after dialysis. However, the mechanism underlying the risk factors and PDF remains unknown. Further research is warranted to investigate the risk factors, intervention, treatment, and mechanism in maintenance hemodialysis patients.

Cadmium and arsenic availability in soil under submerged incubation: The influence of humic substances on iron speciation.

Humic substances (HSs), as electron shuttles, are associated with iron oxide transformation, yet the manner by which HSs affect Cd/As availabilities during this process under anaerobic conditions remains unclear. Two HSs (humic sodium, HA-Na, and biochemical fulvic acid, BFA) were applied at 0, 1, 2, and 4 gCkg-1 in a submerged incubation experiment. The dissolved, extractable and fractions of Cd/As and different iron oxides in soils were monitored. The addition of both HA-Na and BFA decreased the CaCl2-extractable Cd by 12.66-93.13%, and increased the KH2PO4-extractable As by 18.81-71.38% on the 60th day of incubation. The soil Eh and crystalline iron oxides (Fed) decreased, while amorphous iron oxides (Feo) and dissolved As increased after addition of both HSs. However, the two HSs had opposite effects on soil pH and dissolved Cd at the end of the incubation. HA-Na immobilized 19.47-85.99% more available Cd than did BFA over the incubation, although the extent of immobilization was similar with the maximum application rate on the 60th day. BFA mobilized 5.22-26.12% more available As than did HA-Na. XPS data showed that FeOOH decreased while the FeO component increased over the incubation. Correlation analysis and SEM showed that the reduction in the soil Eh and Fed and relative increase in Feo increased the available Cd, while decreased the available As. Consequently, the addition of HA-Na and BFA, particularly combined with flooding irrigation management, could effectively reduce the available Cd in Cd-contaminated soil. However, this method should be used with caution in As-contaminated soil.

Effects of green manure planted in winter and straw returning on soil aggregates and organic matter functional groups in double cropping rice area.

To explore the mechanism of exogenous organic materials enhancing soil organic carbon and soil fertility, based on a long-term experiment located in Hengyang Red Soil Experimental Station, we examined the effects of winter green manure and straw returning patterns (CK, winter fallow; MV, winter Chinese milk vetch; S, early-season rice straw total returning; DS, early-season and late-season rice straw total returning; SMV, winter Chinese milk vetch + early-season rice straw total returning; DSMV, winter Chinese milk vetch + early-season and late-season rice straw total returning) on soil aggregates and organic functional groups. The results showed that the proportion of super aggregates (>2 mm) and macroaggregates (0.25-2 mm) in double cropping rice soil was the highest with a ratio of about 72.1%-81.8%, and the organic carbon content in the two kinds of aggregates was as high as 12.1-20.7 g·kg-1, accounting for 22.7%-59.0% of the total organic carbon. The main organic functional group in paddy soil was polysaccharides, followed by aliphatic carbon and aromatic carbon. The abundance of all those groups was affected by winter Chinese milk vetch growing and straw returning. Compared with other treatments, DSMV significantly increased the proportion of super aggregates (>2 mm) and macroaggregates (0.25-2 mm) and favored the accumulation of inert carbon such as aromatic carbon in the two kinds of aggregates. DSMV could enhance the stability of soil aggregates and organic matter, which had high potential in the real agricultural production.

Effects of composited organic mobilizing agents and their application periods on cadmium absorption of Sorghum bicolor L. in a Cd-contaminated soil.

Organic mobilizing agents have been advocated for phytoremediation of heavy metals contaminated soils, while the effects of application period of such agents remain unclear. A pot experiment was conducted, with two composited organic agents (oxalic acid or citric acid + dissolved organic fertilizer (OA + DOF and CA + DOF)) and four application periods (seeding, jointing, flag leaf and heading stages) of sorghum (Sorghum bicolor L.), to investigate their impacts on Cd bioavailability in soil. Results indicated that application of the two composited agents increased soil dissolved organic carbon (DOC) and DTPA extractable Cd by 7.31-49.13%, Cd contents in roots and shoots by 21.49-72.10%, bioaccumulation factor (BCF) and translocation factor (TF) of shoots by 4.44-71.99%, while reduced soil pH by 0.25-0.53 units, respectively. Most of these indices increased with the application periods, and largely peaked with their application during the flag leaf to heading stages. Meanwhile, the maximum sorghum biomass (132.84 g pot-1) and Cd bioaccumulation quantity (BCQ, 0.71 mg pot-1) in shoots were obtained for the CA + DOF applied at the heading. The DTPA extractable Cd was closely related to soil pH and DOC. Similar close relationships were observed between the Cd contents in shoots and soil DTPA extractable Cd, pH and DOC. The BCQ of Cd was positively related to the shoots biomass rather than their Cd contents. Therefore, the sorghum combined with the CA + DOF may be advocated as an alternative phytoremediation mode in Cd-contaminated soils, and the mobilizing agent should be primarily applied at the heading stage.

The Effects of Deep Brain Stimulation of the Subthalamic Nucleus on Vascular Endothelial Growth Factor, Brain-Derived Neurotrophic Factor, and Glial Cell Line-Derived Neurotrophic Factor in a Rat Model of Parkinson's Disease.

OBJECTIVE: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has evolved as a powerful therapeutic alternative for the treatment of Parkinson's disease (PD). Despite its clinical efficacy, the mechanisms of action have remained poorly understood. In addition to the immediate symptomatic effects, long-term neuroprotective effects have been suggested. Those may be mediated through neurotrophic factors (NFs) like vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF). Here, the impact of DBS on the expression of NFs was analysed in a rat model of PD. METHODS: Unilateral 6-hydroxydopamine (6-OHDA) lesioned rats received DBS in the STN using an implantable microstimulation system, sham DBS in the STN, or no electrode placement. Continuous unilateral STN-DBS (current intensity 50 µA, frequency 130 Hz, and pulse width 52 µs) was conducted for 14 days. Rats were then sacrificed and brains shock frozen. Striata and motor cortices were dissected with a cryostat. Levels of VEGF, BDNF, and GDNF were analysed, both by quantitative PCR and colorimetric ELISA. RESULTS: PCR revealed a significant upregulation of only BDNF mRNA in the ipsilateral striata of the DBS group, when compared to the sham-stimulated group. There was no significant increase in VEGF mRNA or GDNF mRNA. ELISA analysis showed augmentations of BDNF, VEGF, as well as GDNF protein in the ipsilateral striata after DBS compared to sham stimulation. In the motor cortex, significant increases after DBS were observed for BDNF only, not for the other 2 NFs. CONCLUSIONS: The upregulation of trophic factors induced by STN-DBS may participate in its long-term therapeutic efficacy and potentially neuroprotective effects.

[Effects of different organic amendments on soil organic carbon and its labile fractions in the paddy soil of a double rice cropping system]. / æœ‰æœºç‰©æ–™è¿˜ç”°å¯¹åŒå­£ç¨»ç”°åœŸå£¤æœ‰æœºç¢³åŠå ¶æ´»æ€§ç»„åˆ†çš„å½±å“.

Application of organic amendments is an effective approach for improving soil organic carbon and soil fertility. To investigate the effects of different organic amendments on soil organic carbon and its labile fraction content, a batch of incubation experiments was conducted on the fluvo-aquic soil in Dongting Lake region, Hunan Province. There were six treatments, including soil amended with rice straw, soil amended with Chinese milk vetch, soil amended with bio-organic fertilizer, soil amended with pig manure, and soil amended with rice straw-derived biochar, with unamended soil as control. Each treatment had the same amount of carbon input. After 180 days of incubation, application of organic amendments increased soil labile organic carbon content. Application of bio-organic fertilizer, pig manure and rice straw-derived biochar significantly increased soil organic carbon content by 26.1%, 9.7% and 30.7%, respectively. There was no significant change in soil organic carbon content in rice straw and Chinese milk vetch treatments which were more favourable to the accumulation of soil dissolved organic carbon and microbial biomass carbon. Pig manure was more favourable to the accumulation of soil dissolved organic carbon. Bio-organic fertili-zer could benefit the accumulation of soil microbial biomass carbon and readily oxidizable organic carbon. Rice straw-derived biochar could promote the accumulation of soil microbial biomass carbon and light fraction organic carbon. Compared with rice straw, soil carbon pool management index was increased by 31.8%, 111.6%, 62.2% and 50.7% in Chinese milk vetch, bio-organic fertilizer, pig manure and rice straw-derived biochar treatments, respectively. The performance of bio-organic fertilizer, pig manure, and rice straw biochar was better than rice straw and Chinese milk vetch from the perspective of soil carbon sequestration and soil carbon pool management index.

[Effects of exogenous arsenic stress on bacterial and archaeal communities in two types of soils]. / å¤–æºç ·èƒè¿«å¯¹ä¸¤ç§åœŸå£¤ä¸­ç»†èŒå’Œå¤èŒç¾¤è½çš„å½±å“.

Mining, smelting and other activities result in arsenic accumulation in soils, with adverse impacts on the quality and safety of agricultural products and soil microorganisms. We monitored the changes of available arsenic content with incubation time after the addition of exogenous arsenic to the yellow soil (YS) and soil derived from purple sandy shale (RS). The community changes of bacteria and archaea in soils without spiked arsenic and soils after 1, 30 and 360 days of exogenous arsenic stress were measured by MiSeq high-throughput sequencing, to investigate the community adaptative mechanism of bacteria and archaea in soil under arsenic stress. Results showed that the available arsenic content in soils decreased gradually with time, which significantly affected the composition of soil bacteria and archaea community. The abundance of dominant bacterial group changed significantly, whereas only archaea with lower abundance changed obviously, and little change occurred in dominant archaea group, indicating that archaea community had high arsenic tolerance and stability. Compared with the arsenic stress time, soil arsenic availability had greater impacts on community structures of bacteria and archaea. The results could provide refe-rences for safe utilization and microbial remediation of arsenic-contaminated cropland.

[Comparison in cadmium accumulation capacities of different leafy vegetables through cadmium-rich substrate cultivation]. / åˆ©ç”¨å¯Œé•‰åŸºè´¨æ ½åŸ¹å¿«é€Ÿæ¯”è¾ƒä¸åŒå¶èœé•‰ç´¯ç§¯èƒ½åŠ›çš„å·®å¼‚.

To acquire a feasible method for a rapid comparison of the cadmium (Cd) accumulation capacities of different leafy vegetables, using substrate cultivation with different contents of Cd and cultivation time, we compared the observed Cd accumulation capacity with these obtained in the field. The results showed that the Cd content and bio-concentration factors (BCFs) value in the aboveground tissue of leafy vegetable varied significantly with Cd content and cultivation time. Multi-factor analysis of variance showed that vegetable variety, cultivation time, Cd content in substrate and their interaction had significant effects on BCFs of Cd in leafy vegetable. Leafy vegetable variety was the dominant factor affecting BCFs of Cd in leafy vegetable and controlled its absolute level. When Cd content in the substrate reached 1.0 mg·kg-1 with a cultivation of 10 days, the correlation coefficient of Cd BCFs between the substrate cultivation and field experiments was the highest, with a R2 value of 0.90. The results of cluster analysis and one-way ANOVA had the highest consistence with the field results. Comparatively, the substrate cultivation with Cd content of 1.0 mg·kg-1 and a cultivation of 10 days showed a good reproducibility and stability in reflecting the difference in Cd accumulation capacities of different leafy vegetable varieties. The Cd-rich substrate cultivation could be used to screen the vegetables with low Cd accumulation and also would promote the field application of the vegetables with low Cd accumulation in the Cd-contaminated area of China.

The efficacy of repetitive transcranial magnetic stimulation in the treatment of mild cognitive impairment: A meta-analysis / 中华物理医学与康复杂志

Objective:To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on the cognition of patients with mild cognitive impairment (MCI).Methods:The PubMed, Cochrane Library, Embase, Web of Science, CNKI, Wanfang, and VIP databases were searched for randomized controlled trials of rTMS treating MCI patients before March 2019. After screening the literature, extracting the data and two independent reviewers evaluating the quality of the included studies, the meta-analysis was conducted using version 5.3 of the RevMan software.Results:Nine studies covering 368 patients were included. The pooled results showed that compared with sham stimulation, rTMS treatment could effectively improve the cognitive ability (assessed using the Montreal instrument), episodic memory, verbal fluency and the amplitude of MCI patients′ P300 signals. P300 latency was also reduced. However, there was no significant difference, on average, in memory quotient or P300 latency between patients given rTMS plus donepezil hydrochloride and those given donepezil hydrochloride alone. Compared with the control groups, the rTMS treatment groups displayed slightly more frequent adverse reactions, mainly mild dizziness and scalp pain which disappeared within 1-2 hours without obvious residual effects.Conclusions:TMS treatment can effectively improve cognitive and memory function.

Correlation between tumor glucose metabolism and multiparametric functional MRI (IVIM and R2*) metrics in cervical carcinoma: Evidence from integrated 18 F-FDG PET/MR.

BACKGROUND: Multiparameter, multimodality 18 F-FDG PET/MRI holds great potential for the diagnosis of cervical cancer based on the correlation between tumor glucose metabolism and imaging parameters. PURPOSE: To characterize the heterogeneity of tumor glucose metabolism by evaluating the correlation between 18 F-FDG uptake parameters and multiparametric functional MRI metrics in cervical carcinoma. STUDY TYPE: Retrospective. POPULATION: Fifty-four patients with cervical carcinoma. FIELD STRENGTH/SEQUENCE: Hybrid PET/MR (3T), multi-b DWI, and R2* mapping. ASSESSMENT: The maximum and mean standardized uptake values (SUVmax and SUVmean , respectively) from PET and functional MRI metrics (D, D*, f, and R2*) were obtained. Cervical carcinoma tissues also underwent HIF-1α, VEGF, and GLUT-1 immunohistochemical staining. STATISTICAL TESTS: Single-factor Spearman rank and Pearson correlation analysis and multiple linear regression (MLR) analysis were applied. RESULTS: R2*, D, and f have different degrees of correlation (moderate, weak, moderately strong correlation, respectively) with SUVmax and SUVmean (r = 0.530 and 0.527, and P < 0.001 for R2*; r = -0.292 and -0.291, and P < 0.05 for D; r = 0.539 and 0.520, and P < 0.001 for f, respectively). Immunohistochemical staining showed that HIF-1α expression has a moderate degree of correlation with R2* (r = 0.491; P < 0.001); GLUT-1 expression was significantly correlated with SUVmax and SUVmean (r = 0.633 and 0.622; P < 0.001), and VEGF expression had a moderately strong correlation with f (r = 0.457; P = 0.001). If SUVmax is the dependent variable, MLR yields an R-squared value after adjustment (adjusted R-squared) = 0.358, and F = 10.833 (P < 0.001), and the fitting linear equation is Y (SUVmax ) = 9.184 + 0.161X1 (R2*)+50.343X2 (f)-4.780 (D). Otherwise, MLR yields the adjusted R-squared = 0.342, and F = 10.187 (P < 0.001), and the linear regression equation is Y (SUVmean ) = 5.925 + 0.102X1 (R2*)+28.029X2 (f)-2.907X3 (D). DATA CONCLUSION: The functional MRI sequence parameters R2*, f, and D can provide information on the hypoxic condition, blood perfusion, and molecular diffusion of the tumor. 18 F-FDG PET/MR multi-imaging technique can be adopted to evaluate the heterogeneity of glucose metabolism in cervical carcinoma. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:1704-1712.

[Accumulation Characteristics of Heavy Metals in Greenhouse Soil and Vegetables in Siping City, Jilin Province].

Based on the typical greenhouse vegetable production system in Siping City, Jilin Province, 124 soil samples were collected from greenhouse soils growing vegetables (GSGV), fields growing maize (FGM), and forest soil (FS) under different land utilization patterns. In addition, other samples including greenhouse vegetables (81), fertilizers (50), and irrigation water (10) were also collected in the studied region. To illustrate the accumulation characteristics of heavy metals in GSGV and greenhouse vegetables, the heavy metal content of different samples was measured using inductively coupled plasma mass spectrometry (ICP-MS) technology. The results indicated that the heavy metal content in GSGV was much higher than that in FGM and FS except for lead (Pb). Heavy metals including cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) in GSGV presented with various degrees of accumulation. The mean value of Cd content in the soils in the investigation region was 0.45 mg·kg-1, with about 42.8% of all the soil samples exceeding the Cd content criterion of the Environmental Quality Evaluation Standard for Farmland in Greenhouse Vegetable Production (HJ 333-2006). The content of the other heavy metals was in the normal range, and all met the regulations of the standard. In comparison with different vegetable categories, leafy vegetables showed much higher heavy metal concentrations (Cd 0.033 mg·kg-1 fresh weight) than did fruity ones. In total, about 2.5% and 1.2% of vegetable samples exceeded the regulated values of Cd and Pb recommended by the Standard of Food limits, respectively. With the cultivation time prolonged, heavy metal concentration in soils and vegetables all increased synchronously as the pH value decreased. The content of heavy metals in greenhouse vegetables was significantly influenced by soil pH and organic matter. It can be concluded that the health risk of greenhouse vegetables increased with GSGV accumulating more heavy metals due to the substantial application of chemical fertilizer and manure containing high level of heavy metals.

[Effects of different fertilization regimes on nitrogen and phosphorus balance and eco-economic benefits in red paddy field.] / 不同施肥措施对红壤稻田氮磷平衡及生态经济效益的影响.

The nitrogen (N) and phosphorus (P) balance was studied and the eco-economic benefits of N and P were evaluated for the paddy field in a red soil area, under the fertilization treatments of no fertilization (CK), chemical fertilizer (NPK), organic fertilizer (M), and chemical fertilizers combined with organic fertilizers (NPKM, NPM, NKM), based on the long-term experiment started in 1982, to optimize fertilizer application and reduce N and P losses. The results indicated that the slight N surplus (27.10 kg·hm-2) and P deficit (-6.85 kg·hm-2) were obtained in CK, while the N and P surplus respectively with 110.94-243.98 kg·hm-2 and 19.06-67.49 kg·hm-2 in other treatments were obtained. The treatments NPK and M had no effects on the N and P balance. Under the same fertilization rates, the N surplus in treatment NPKM was lower than that in treatments NPM and NKM by 6.3% and 12.9%, while the P surplus was lower by 3.7% and 13.8%, respectively. The total-N, total-P, alkali-hydrolyzable N, and available P contents in the 0-20 cm soil layer increased under the treatments of NPKM. Comparatively, the available P contents were relatively higher in the 20-40 cm soil layer under the treatments of high P application rates. Furthermore, the NPKM treatment had the highest eco-economic benefit value of 0.762, which indicated the optimized fertilizer application for the paddy fields in the red soil area. The treatment CK had the lowest eco-economic benefit values with 0.560. Based on the observations, the N and P (in P2O5) fertilization respectively at the rates of 157.71 kg·hm-2 and 112.18 kg·hm-2 could well maintain the N and P balance for the paddy field in the red soil area.

[Soil Olsen-P content changing trend and its relationship with phosphorus surplus and crop yield under long-term fertilization in loessial soil region on the Loess Plateau, China]. / é•¿æœŸæ–½è‚¥é»„ç»µåœŸæœ‰æ•ˆç£·å«é‡æ¼”å˜åŠå ¶ä¸Žç£·ç´ å¹³è¡¡å’Œä½œç‰©äº§é‡çš„å ³ç³».

The changing trend of soil available phosphorus (Olsen-P) content in soil and its relationship with soil phosphorus surplus and crop yield are fundamental when making appropriate phosphate fertilizer recommendations. In this paper, the influences of long-term fertilization on crops phosphorus uptake, soil phosphorus surplus, changing trend of soil available phosphorus content and relationships of soil available phosphorus content with soil phosphorus surplus and crop yield were investigated through 34 years (1981-2015) long-term trial in loessial soil region on the Loess Plateau. The experiment had a completely-randomized-block split-plot design in triplicate. Two main-plot treatments were no farmyard manure and farmyard manure (M), and four subplot treatments were CK (no fertilizer), N (application of chemical fertilizer N), NP (application of chemical fertilizer NP) and NPK (balanced application of chemical fertilizer NPK), respectively. The results showed that fertilization treatments and crop types significantly influenced uptake amount of phosphorus and soil phosphorus surplus. Averaged over time from 1981 to 2015, wheat mean phosphorus uptake amounts of CK, N, NP, NPK, M, MN, MNP and MNPK were 8.63, 10.64, 16.22, 16.21, 16.25, 17.83, 20.39 and 20.27 kg·hm-2, while rape phosphorus uptakeamounts of eight treatments were 4.40, 8.38, 15.08, 15.71, 10.52, 11.23, 17.96 and 17.66 kg·hm-2, respectively. The surplus amount of soil phosphorus significantly correlated with the amount of phosphorus applied to soil. When soil phosphorus surplus amount equal zero, wheat and rape phosphorus input amounts were 10.47 kg·hm-2 and 6.97 kg·hm-2, respectively. Soil phosphorus surplus amount significantly influenced the changing trend of available phosphorus content in soil. CK and N treatments had no phosphorus input, and soil available phosphorus content exhibited a declining trend, annually decreased by 0.16 mg·kg-1 and 0.15 mg·kg-1, respectively. In contrast, NP, NPK, M, MN, MNP and MNPK six treatments were applied with phosphate fertilizer every years, and available phosphorus content gradually increased along with the duration of trial, with annual increase by 0.02-0.33 mg·kg-1. Soil available phosphorus content significantly correlated with phosphorus accumulative surplus amount, and the linear models were y=0.012x+9.33 and y=0.009x+11.72 in manure and no manure treatments, respectively. In no manure treatments, wheat yields significantly positively correlated with soil available phosphorus content, however, in manure treatments, their relationships did not reach a significant level. The relationship of wheat grain yield with available phosphorus content could be significantly fitted by piecewise linear model, and available phosphorus agronomy threshold of wheat was 14.99 mg·kg-1. Rape grain yield also increased with increasing soil available phosphorus content, but the relationship was not significant. This indicated when soil available P content is higher than 14.99 mg·kg -1, application of phosphate fertili-zer should be reduced or even avoided for planting wheat in loessial soil region on the Loess Plateau.

[Effects of long-term fertilization on nitrogen fertilizer use efficiency in loessial soil region on the Loess Plateau, Northwest China]. / 长期施肥对黄土高原黄绵土氮肥利用率的影响.

Nitrogen fertilizer use efficiency is a key parameter to determine recommended nitrogen fertilizer amount and evaluate the effects of nitrogen fertilizer application. The effects of long-term fertilization on annual and accumulated nitrogen fertilizer use efficiency and the relationship between them were studied using a 34-year fertilization experiment (1981-2015) in loessial soil region. The results showed that fertilization had significant influence on annual and accumulated nitrogen ferti-lizer use efficiency of wheat, rape and flax in the period of 1983-2015. The highest mean annual nitrogen fertilizer use efficiency of wheat was achieved in N, P and K combination (NPK), thesecond was N combined with P (NP), 77.7% and 62.0% higher than N application alone respectively. The highest mean annual nitrogen fertilizer use efficiency of rape was achieved in NPK, the second was manure (M), N, P and K combination (MNPK), 93.7% and 65.6% higher than N application alone respectively. The annual nitrogenfertilizer use efficiency of M combined with N (MN) increased significantly compared with N application alone. The annual nitrogen fertilizer use efficiency of M, N and P combination (MNP) decreased significantly compared with NP. The annual nitrogen fertilizer use efficiency of MNPK decreased significantly compared with NPK.There was significant positive linear relationship between annual nitrogen fertilizer use efficiency and crop yield. The correlation between accumulated nitrogen fertilizer use efficiency and crop yield was not significant. It indicated that the annual nitrogen fertilizer use efficiency could be more effective in representing fertilizer use efficiency characteristics under given soil fertility levels, crop varieties and environmental conditions compared with accumulated nitrogen fertilizer use efficiency.

[Aging process of arsenite [As(3)]in soils originated from different parent materials.] / 外源As(⠢)在不同母质发育土壤中的老化过程.

An incubation test was conducted to study the bioavailability and fractionations of exogenous arsenite [As(3)] during the aging period in three soils originated from different parent materials, including quaternary red clay, purple sandy shale and granite. The results indicated that the exogenous arsenite As(3) were totally transformed into As(V) after 120 d aging. The available As content in soils derived from the three soils generally decreased sequentially throughout the aging period in the order of purple sandy shale, granite and quaternary red clay. The pseudo-second-order model well fitted the change of available As content with aging time (P＜0.05). Soil pH, organic matter (SOM) content and the concentrations of Fe, Al and Mn oxides were the main factors influencing the red soil arsenic in aging, especially, Mn oxides played a more crucial role than Fe and Al oxides in As aging (P＜0.05). Correlation analysis revealed that the non-specially and specially absorbed As constituted the primary forms of available As.

Clinical analysis of LASlK treatment resulted in overcorrection in Tibetan Plateau / 国际眼科杂志(Guoji Yanke Zazhi)

AlM:To investigate the factors and solutions of Tibetan Plateau excimer laser in situ keratomileusis ( LASlK ) for myopia overcorrection.METHODS: The relevant information, 32 cases ( 58 eyes) in 126 cases (252 eyes) had obvious overcorrection after LASlK were analyzed.RESULTS: Two months after surgery, 32 cases ( 58 eyes) overcorrection (23. 0%), uncorrected visual acuity of 0. 5 ~0. 8, overcorrection range of +1. 50 ~ +2. 25DS, subjective inserts were ≥ 1. 0; Five case ( 7 eyes ) overcorrection 6mo after surgery (2. 8%), uncorrected visual acuity 0. 8~1. 0-2 , overcorrection range is +0. 75 ~+1. 25DS, subjective inserts were≥1. 0. Corneal thickness of overcorrection was 500~563μm, preoperative refraction was -5. 00 ~ -7. 50D, astigmatism -1. 50 ~ -2. 75DC, preoperative best corrected visual acuity ≥1. 0.CONCLUSlON: Overcorrection and long recovery time after LASlK in Tibet, possibly with local factors altitude, temperature, humidity, surgical parameters and situation.

Effect of Bear Bile Powder and Its Succedaneum on Peripheral Blood and Bone Marrow Megakaryocytes in Mouse Model with Thrombocytopenia Induced by Cytosine Arabinoside / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of bear bile powder and ursodesxy cholic acid (UDCA) on peripheral blood, bone marrow megakaryocyte and immune organs in mouse model with thrombocytopenia, so as to provide a reference for studying the curative effects of bear bile powder and its succedaneum on thrombocytopenic purpura (TP).</p><p><b>METHODS</b>The mouse model with thrombocytopenia indued by cytosine arabinoside (Ara-C) was established, a total of 70 mice were randomly divided into normal group, model group, prednisone group, bear bile (middle and high dose) powder group and UDCA (middle and high dose) group. From the first day of making model mice in the each group, 0.4 ml/(20 g·d) corresponding drug was administered by infusion. At day 10 after treatment the peripheral blood, spleen and thymus organ index, the number of bone marrow megakaryocyte in each group were compared.</p><p><b>RESULTS</b>compared with the normal group, the Plt, WBC and megakaryocyte counts in model group decreased, the spleen index increased obviously (P<0.05), but the WBC count returned to normal by 10 days; after treatment, compared with model group, the Plt, WBC and megakaryocyte counts of treated groups increased, spleen index decreased significantly (P<0.05), but the WBC count in prednisone group decreased, which in bear bile powder (high) group and UDCA (high) group were particularly significant.</p><p><b>CONCLUSION</b>The bear bile powder and UDCA have been confirmed to have therapeutical effect on thrombocytopenia models induced by Ara-C, UDCA can substitute bear bile powder as a treatment drug for thrombocytopenic purpura.</p>