Health risk assessment of trace metal(loid)s in agricultural soils based on Monte Carlo simulation coupled with positive matrix factorization model in Chongqing, southwest China

This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization(PMF) model and health risk assessment(HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium(Cd), arsenic (As), lead(Pb), chromium(Cr), copper(Cu), nickel(Ni), and zinc(Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, noncarcinogenic risks were deemed negligible(hazard index <1), the carcinogenic risks were at acceptable level(10^(-6)<total carcinogenic risk ≤ 10^(-4)), with higher risks observed for children compared to adults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors.

Affective Factors——Key Factors Influencing College Learners'Classroom

Foreign language teaching has shifted from teacher-centered teaching method to student-centered in recent years.Affective factors should be paid enough attention in teacher-learner interaction in.This paper aims to make an exploration into the effects of affective factors in college learners'classroom.

Factors Influencing Second Language Learners' Goal Setting

Goalsetting, as one of the most important meta-cognitive strategies in learning, has gained considerable attention (Bruce,2011). A number of studies have focused on the positive effect of goal setting in sustaining motivation, promoting self-efficacy andfostering autonomy. However, few research seems to examine the factors that influence second language learners’goal setting. Thecurrent study aims to address this gap by investigating the goal setting processes of two postgraduate learners at Tianjin ForeignStudies Universities. Interviews were triangulated to obtain a deep understanding. Findings revealed that motivation, self-efficacy,learning strategy, time management can all have influences on the language learners’goal-setting.

Logistic Regression Analysis of the Influencing Factors of Cryptogenic Stroke with Positive c-TCD

Objective:To explore the influencing factors and logistic regression characteristics of cryptogenic stroke in patients with positive transcranial doppler bubble test(c-TCD).Methods:A total of 134 cases of cryptogenic stroke that were diagnosed by Tianshui First People's Hospital from November 2018 to April 2020 were selected according to the TOAST(Trial of ORG 10172 in Acute Stroke Treatment)classification criteria.According to c-TCD results,there were 70 cases of right to left shunt that were included in the positive group and 64 cases without right to left shunt in the negative group.Gender,age,smoking,diabetes,hypertension,and factors affecting the positive rate of foam were analyzed.According to the abnormal embolism scale scores,logistic regression equation was used to analyze the independent influencing factors.Results:The influencing factors of cryptogenic stroke in patients with positive c-TCD were correlated with age,gender,and abnormal embolism scale scores(p<0.05).For each grade increase in age,the proportion of positive foam test was calculated to be 3.21 times,and the proportion of female to male was calculated to be 2.25 times.For each grade increase in the scores,the proportion of positive foam test was calculated to be 2.55 times.Conclusion:Female,older age,and higher scores in the abnormal embolism scale are the influencing factors for cryptogenic stroke in patients with positive c-TCD.

Construction Strategy and Affecting Factors of Positive-Strand RNA Virus Infectious Clone

Construction of infectious clones by full-length cDNA is basic and key for recovering RNA virus and is core of reverse genetics.In this article,basic consideration and key technology were viewed and factors affecting infectivity of clones were also summarized.Some research advances were briefly introduced about positive-strand RNA viruses infectious clones.Finally,this article also reviewed the application of infectious clones.

Relationships between temperature-light meteorological factors and seedcotton biomass per boll at different boll positions

Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorological factors for seedcotton biomass per boll with respect to boll positions. Field experiments were conducted using two cultivars of Kemian 1 and Sumian 15 with three planting dates of 25 April （mean daily temperature （MDT） was 28.0 and 25.4°C in 2010 and 2011, respectively）, 25 May （MDT was 22.5 and 21.2°C in 2010 and 2011, respectively）, and 10 Jun （MDT was 18.7 and 17.9°C in 2010 and 2011, respectively）, and under three shading levels （crop relative light rates （CRLR） were 100, 80, and 60％） during 2010 and 2011 cotton boll development period （from anthesis to boll open stages）. The main meteorological factors （temperature and light） affected seedcotton biomass per boll differently among different boll positions and cultivars. Mean daily radiation （MDR） affected seedcotton biomass per boll at all boll positions, except fruiting branch 2 （FB2） fruting node 1 （FN1）. However, its influence was less than temperature factors, especially growing degree-days （GDD）. Optimum mean daily maximum temperature （MDTmax） for seedcotton biomass per boll at FB11FN3 was 29.9-32.4°C, and the optimum MDR at aforementioned position was 15.8-17.5 MJ m-2. Definitely, these results can contribute to future cultural practices such as rational cultivars choice and distribution, simplifying field managements and mechanization to acquire more efficient and economical cotton management.

Different distributions of interstitial cells of Cajal and platelet-derived growth factor receptor-α positive cells in colonic smooth muscle cell/interstitial cell of Cajal/plateletderived growth factor receptor-α positive cell syncytium in mice

AIM To investigate the distribution and function of interstitialcells of Cajal(ICCs) and platelet-derived growth factor receptor-α positive(PDGFRα+) cells in the proximal and distal colon.METHODS The comparison of colonic transit in the proximal and distal ends was performed by colonic migrating motor complexes(CMMCs). The tension of the colonic smooth muscle was examined by smooth muscle spontaneous contractile experiments with both ends of the smooth muscle strip tied with a silk thread. Intracellular recordings were used to assess electrical field stimulation(EFS)-induced inhibitory junction potentials(IJP) on the colonic smooth muscle. Western blot analysis was used to examine the expression levels of ICCs and PDGFRα in the colonic smooth muscle.RESULTS Treatment with NG-nitro-L-arginine methyl ester hydrochloride(L-NAME) significantly increased the CMMC frequency and spontaneous contractions, especially in the proximal colon, while treatment with MRS2500 increased only distal CMMC activity and smooth muscle contractions. Both CMMCs and spontaneous contractions were markedly inhibited by NPPB, especially in the proximal colon. Accordingly, CyPPA sharply inhibited the distal contraction of both CMMCs and spontaneous contractions. Additionally, the amplitude of stimulationinduced nitric oxide(NO)/ICC-dependent slow IJPs(sIJPs) by intracellular recordings from the smooth muscles in the proximal colon was larger than that in the distal colon, while the amplitude of electric field stimulationinduced purinergic/PDGFRα-dependent fast IJPs(fIJPs) in the distal colon was larger than that in the proximal colon. Consistently, protein expression levels of c-Kit and anoctamin-1(ANO1) in the proximal colon were much higher, while protein expression levels of PDGFRα and small conductance calcium-activated potassium channel 3(SK3) in the distal colon were much higher.CONCLUSION The ICCs are mainly distributed in the proximal colon and there are more PDGFRα+ cells are in the distal colon, which generates a pressure gradient between the two ends of the colon to propel the feces to the anus.

Navigating breast cancer brain metastasis:Risk factors,prognostic indicators,and treatment perspectives

In this editorial,we comment on the article by Chen et al.We specifically focus on the risk factors,prognostic factors,and management of brain metastasis(BM)in breast cancer(BC).BC is the second most common cancer to have BM after lung cancer.Independent risk factors for BM in BC are:HER-2 positive BC,triplenegative BC,and germline BRCA mutation.Other factors associated with BM are lung metastasis,age less than 40 years,and African and American ancestry.Even though risk factors associated with BM in BC are elucidated,there is a lack of data on predictive models for BM in BC.Few studies have been made to formulate predictive models or nomograms to address this issue,where age,grade of tumor,HER-2 receptor status,and number of metastatic sites(1 vs>1)were predictive of BM in metastatic BC.However,none have been used in clinical practice.National Comprehensive Cancer Network recommends screening of BM in advanced BC only when the patient is symptomatic or suspicious of central nervous system symptoms;routine screening for BM in BC is not recommended in the guidelines.BM decreases the quality of life and will have a significant psychological impact.Further studies are required for designing validated nomograms or predictive models for BM in BC;these models can be used in the future to develop treatment approaches to prevent BM,which improves the quality of life and overall survival.

Individual Learner Factors Affecting Second Language Acquisition

In Second Language Acquisition(short for SLA) research,the study of individual learner factors plays an important role.In this paper,discussion will be restricted to five general individual learner factors which have received the most attention in SLA research:age,cognitive style,personality,motivation and attitude.The research will,to some extent,not only develop the SLA theory,but also enhance learners' judgments to their own individual learner factors.It can also shed light on the practical foreign language learning.

Effect of basic fibroblast growth factor and danshen on bcl-2 and p53 mRNA expression in the brain of rats exposed to repeated, high, positive acceleration (+Gz)

BACKGROUND： Both animal experiments and clinical studies have shown that basic fibroblast growth factor （bFGF） and danshen （Salvia miltiorrhiza） can exhibit protective effects on ischemia-reperfusion cerebral injury. OBJECTIVE： To test whether bFGF and danshen can protect cerebral injury induced by exposure to repeated, high, positive acceleration （＋Gz） in an animal model and to analyze the possible mechanisms. DESIGN, TIME AND SETTING： Randomized controlled animal study. The experiment was performed at the Research Center for Molecular Biology, Air-force General Hospital of Chinese PLA from April to August 2000. MATERIALS： A total of 20 clean grade, healthy, Sprague Dawley rats of both genders, weighing （200 ± 15） g, were provided by our experimental animal center. Rats were randomly divided into 5 groups： the control group, ＋Gz exposure group, bFGF group, danshen group, and saline group, with 4 animals per group. bFGF （Beijing Bailuyuan Biotechnology Co. Ltd.） and danshen solution （Shanghai Zhongxi Pharmaceutical Co. Ltd.） were used. METHODS： All rats were fixed on a rotary arm of a centrifugal apparatus （2 m in radius） with their heads oriented towards the center of the apparatus. Except for rats in the control group, the value of ＋Gz exposure was ＋14 Gz with an acceleration rate of 1.5 G/s. The peak force lasted for 45 seconds. ＋Gz exposure was performed three times with intervals of 30 minutes. Rats in the control group received the same ＋Gz procedure, but the G value was ＋1 Gz. Rats in bFGF group and danshen group were intraperitoneally injected with 100 μg/kg bFGF or 15 g/kg danshen solution, respectively, at 30 minutes prior to centrifugation and immediately after centrifugation. Rats in saline group were injected with the same volume of saline. Six hours after exposure, rats were decapitated. One hemisphere was preserved in liquid nitrogen for RNA extraction and the other was processed for apoptosis detection. MAIN OUTCOME MEASURES： mRNA levels of bcl-2 and p53 were measured by semi-quantitative reverse-transcription polymerase chain reaction. Apoptotic cell death was detected by terminal deoxynuleotidyl transferase-mediated dUTP nick end labeling. RESULTS： Changes in mRNA expression of bcl-2 and p53 and apoptotic cells were observed in rat brain six hours after repeated ＋Gz exposures, bFGF and danshen were able block the changes of bcl-2 and p53 expression and inhibit apoptotic cell death. CONCLUSION： The data suggest that apoptosis and changes in bcl-2 and p53 expression in the rat brain can be induced by repeated ＋Gz exposures. Apoptosis is, therefore, one of the molecular mechanisms of brain damage induced by repeated ＋Gz exposures, bFGF and danshen were of the equal potency in preventing brain injury induced by repeated ＋Gz exposures.

A DNA-binding protein factor in K562 nuclear extract interacts with positive control region (PCR) in the 5'flanking sequence of human β-globin gene

It has been known that there are at least three regulatory regions (NCR1, NCR2 and PCR) in the 5'-flanking sequence (from -610 bp to +1bp) of human β-globin gene and that the function of PCR is unique to the human erythroleukemia (K562) cells. Here we have detected a DNA-binding protein factor (termed NFEa) in K562 cells, which can bind specifically to the PCR of human β-globin gene. The sequence of the binding site is 5'ACTGATG3' (between -222 bp and -216 bp). The NFEa is erythroid-specific and perhaps specific for K562 cells. It seemed that this factor differed from the erythroid-specific tran-scriptional factor (NFE-1) using competition assay. The presence of the NFEa further supported that the function of the cis-acting element PCR was specific for K562 cells, and helps us to understand the mechanism of the regulation of the expression of human β-globin gene in the human K562 cells.

Tyrosine kinase inhibitors and human epidermal growth factor receptor-2 positive breast cancer

The body of evidence investigating human epidermal growth factor receptor-2(HER2)directed therapy in patients with breast cancer(BC)has been growing within the last decade.Recently,the use of tyrosine kinase inhibitors(TKIs)has been of particular interest in the treatment of human malignancies.This literature commentary is intended to highlight the most recent findings associated with the widely-studied TKI agents and their clinical significance in improving the outcomes of HER2 positive BC.

Human epidermal growth factor receptor 2 positive rates in invasive lobular breast carcinoma: The Singapore experience

BACKGROUND Invasive lobular carcinomas(ILC)form 5%-10%of breast cancer and rarely show overexpression of human epidermal growth factor receptor 2(HER2).AIM To describe the prevalence and prognostic factors of HER2 positive(HER2+)ILC in an Asian population.METHODS A retrospective review of patients with ILC seen between January 1985 and March 2018 at various SingHealth medical institutions was conducted.Demographic and clinical data were collected from medical records.We examined clinicopathological characteristics and survival in relation to HER2 status.RESULTS A total of 864 patients were included.Prevalence of HER2 positivity was 10.1%(87 patients).Compared with HER2 negative(HER2-)ILC,HER2+ILC was associated with a higher proportion of estrogen receptor negative(24.4%vs 5.9%,P<0.001),progesterone receptor negative(PR-)(40.2%vs 24%,P=0.002)and grade 3 tumours(Grade 3,29.0%vs 10.2%,P<0.001).Overall survival rate was poorer in patients with HER2+compared to HER2-ILC(56.7%vs 72.9%alive at 10 years;hazard ratio 1.87,95%confidence interval:1.21-2.90,P=0.004).Based on multivariate analysis,negative prognostic factors for overall survival included HER2 positivity,PR negativity,older age,Indian ethnicity and higher tumour stage.CONCLUSION Prevalence of HER2+ILC was 10.1%.HER2+ILC was more likely to have poorer prognostic features such as estrogen receptor negative,PR-and higher tumour grade,and have a poorer survival.

On the Factors Influencing Learner Autonomy in Chinese EFL Contexts

Since late 1970s, worldwide EFL classrooms have witnessed the change from teacher-centered learning to learner-centered and more effective language learning. Research findings have shown repeatedly the importance of developing learner autonomy. Based on the review of the relevant literature both in China and around the world, the present paper discusses the main factors affecting the promotion of EFL learner autonomy in China, including motivation, learners＇ metacognitive knowledge and learning environment. Some strategies for fostering learner autonomy are also recommended.

Available Contents of Trace Nutrient Element and Factors Affecting Their Availability in Western Jilin

Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient elements and their affecting factors are studied. The results show that the available B in western Jilin is in a middle level,the content in Nong'an is higher than that in the others; the available Mn is extremely abundant; the available Cu in Nong'an is obviously higher than other areas,and the content in Da'an differs greatly; the available Zn is in a middle level; the severe shortage of available Mo differs between different areas; and the available Fe is extremely abundant. The available Mn,Cu and Fe have significantly positive correlation with their total content; the available B has significantly positive correlation with pH,and Zn has obviously negative correlation with pH; the available Mn and Fe had significantly positive correlation with soil organic matter.

Positive Rate of Different Hepatitis B Virus Serological Markers in Peking Union Medical College Hospital,a General Tertiary Hospital in Beijing

Objectives To investigate the positive rate of different hepatitis B virus （HBV） serological markers, and the demographic factors related to HBV infection. Methods We enrolled all patients tested for HBV serological markers, such as HBV surface antigen （HBsAg）, HBV surface antibody （HBsAb）, hepatitis B e antigen （HBeAg）, hepatitis B e antibody （HBeAb）, HBV core antibody （HBcAb）, and HBV-DNA from July 2008 to July 2009 in Peking Union Medical College Hospital. The positive rate of each HBV serological marker was calculated according to gender, age, and department, respectively. The positive rates of HBV-DNA among patients with positive HBsAg were also analyzed. Results Among 27 409 samples included, 2681 （9.8%） were HBsAg positive. When patients were divided into 9 age groups, the age-specific positive rate of HBsAg was 1.2%, 9.6%, 12.3%, 10.9%, 10.3%, 9.7%, 8.0%, 5.8%, and 4.3%, respectively. The positive rate of HBsAg in non-surgical department, surgical department, and health examination center was 16.2%, 5.8%, and 4.7%, respectively. The positive rate of HBsAg of males （13.3%） was higher than that of females （7.3%, P=0.000）. Among the 2681 HBsAg （＋） patients, 1230 （45.9%） had HBV-DNA test, of whom 564 （45.9%） were positive. Patients with HBsAg （＋）, HBeAg （＋）, and HBcAg （＋） result usually had high positive rate of HBV-DNA results （71.8%, P=0.000）. Conclusions Among this group of patients in our hospital, the positive rate of HBsAg was relatively high. Age group of 20-29, males, and patients in non-surgical departments were factors associated with high positive rate of HBsAg.

The Motivations of Chinese EFL Learners

English is regarded as the international language,which makes it the most popular language to learn around the world.Among the many factors that affect the learning outcomes of English language,motivation is broadly considered as one of the most important ones.This paper presents a general review on types of motivation as well as the factors that are linked to motivation.This paper also touches upon some critical issues that Chinese EFL learners face in terms of motivation in English learning.

Generating Totally Positive Toeplitz Matrix from an Upper Bidiagonal Matrix

In this paper, we construct one of the forms of totally positive Toeplitz matrices from upper or lower bidiagonal totally nonnegative matrix. In addition, some properties related to this matrix involving its factorization are presented.

The Importance of Learning Chinese Outside Classroom(A Study of Good Chinese Learners at The University of Hong Kong)

This is the author’s second consecutive year of doing the research.As the economy of China is booming,there is a rapid increase in the number of foreign students coming to The University of Hong Kong to learn Chinese.As Chinese is one of the popular subjects for them to choose,in 2019,there are around 1000 foreign students(undergraduates or exchange students)learning Chinese as a foreign language course.A language teacher is a facilitator and an instructor of Chinese learning for foreign students.However,in the real world,there are always some good language learners and some less talented language learners in one classroom.So,what is the secret of the good Chinese learners?What can the language instructors do in order to support good Chinese learners and help the less talented learners to learn Chinese?In the TESOL field,there are a lot of researches have been done by scholars.In the early 1970s,several researchers isolated and defined the concept of good language learner.But in teaching Chinese as a foreign language field,there are relatively fewer researches.So,from January 2017 to May 2019,I conducted a survey about good Chinese learners in CHIN9503 and CHIN9504 classes.The survey consisted of an interview with several questions and the author will discuss the result of a survey and its implications in this paper.This research is done in a macro way rather than micro way.Thus,this holistic research focuses on finding good Chinese learners rather than focusing on learners’individual differences.

Affective Factors in the Communicative Classroom

Recent years has witnessed the great efforts made to investigate the relationship between language and affective factors. This essay serves both to focus awareness on the role of affective factors in the communicative classroom and to show how affective factors influence many different aspects of communicative language teaching/learning. A survey is also conducted on the communicative language teaching to illustrate affective factors in the communicative classroom.