Li Li

China Agriculture University-East, Peping, Beijing, China

Are you Li Li?

Claim your profile

Publications (21)52.35 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A series of novel tetramethylguanidinium ionic liquids and hexaalkylguanidinium ionic liquids have been synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids were confirmed by 1H NMR spectroscopy and mass spectrometry. A green guanidinium ionic liquid based microwave-assisted extraction method has been developed with these guanidinium ionic liquids for the effective extraction of Praeruptorin A from Radix peucedani. After extraction, reversed-phase high-performance liquid chromatography with UV detection was employed for the analysis of Praeruptorin A. Several significant operating parameters were systematically optimized by single-factor and L9 (34) orthogonal array experiments. The amount of Praeruptorin A extracted by [1,1,3,3-tetramethylguanidine]CH2CH(OH)COOH is the most, reaching 11.05 ± 0.13 mg/g. Guanidinium ionic liquid based microwave-assisted extraction presents unique advantages in Praeruptorin A extraction comparing with guanidinium ionic liquid based maceration extraction, guanidinium ionic liquid based heat reflux extraction and guanidinium ionic liquid based ultrasound-assisted extraction. The precision, stability and repeatability of the process were investigated. The mechanisms of guanidinium ionic liquid based microwave-assisted extraction were researched by scanning electron microscopy and IR spectroscopy. All the results show that guanidinium ionic liquid based microwave-assisted extraction has a huge potential in the extraction of bioactive compounds from complex samples.This article is protected by copyright. All rights reserved
    Journal of Separation Science 12/2014; 37(23). DOI:10.1002/jssc.201400828 · 2.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Avian influenza virus H5 is a widespread virus among humans and animals which has caused fatally systemic diseases through poultry-to-person transmission in the past few years. Reverse transcription polymerase chain reaction (RT-PCR) has been proved to be an effective approach for the identification and detection of avian influenza viruses. However, conventional tube RT-PCR is slow and reagent consuming and cannot meet the need for rapid and low cost detection of pathogenic bacteria and viruses. Microfluidic PCR is a burgeoning field among the techniques based on molecular analysis. In this paper, we reported a microfluidic PCR system that integrated RT-PCR and real time fluorescence detection for rapid identification of avian influenza virus H5. This microfluidic device mainly consisted of a thermal controlling unit providing actuation for the temperature cycling needed for amplification, an optical inspection system for online recording fluorescence and a microfluidic chip fabricated using polydimethylsiloxane (PDMS). In this study, influenza virus H5 from clinical chicken throat swab specimens was rapidly detected using the RT-PCR microfluidic system, which was consistent with the results of embryonated egg culture. Compared with a large-scale device, the integrated microfluidic system presented here can perform rapid nucleic acid amplification and analysis, possibly making it a crucial platform for pathogenic bacterium and virus detection in the future.
    Analytical methods 01/2014; 6(8):2628. DOI:10.1039/c3ay42126k · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sex hormones and gonadotropins exert a wide variety of effects in physiological and pathological processes. Accumulated evidence shows a strong heritable component of circulating concentrations of these hormones. Recently, several genome-wide association studies (GWASs) conducted in Caucasians have identified multiple loci that influence serum levels of sex hormones. However, the genetic determinants remain unknown in Chinese populations. In this study, we aimed to identify genetic variants associated with major sex hormones, gonadotropins, including testosterone, oestradiol, follicle-stimulating hormone (FSH), luteinising hormone (LH) and sex hormone binding globulin (SHBG) in a Chinese population. A two-stage GWAS was conducted in a total of 3495 healthy Chinese men (1999 subjects in the GWAS discovery stage and 1496 in the confirmation stage). We identified a novel genetic region at 15q21.2 (rs2414095 in CYP19A1), which was significantly associated with oestradiol and FSH in the Chinese population at a genome-wide significant level (p=6.54×10(-31) and 1.59×10(-16), respectively). Another single nucleotide polymorphism in CYP19A1 gene was significantly associated with oestradiol level (rs2445762, p=7.75×10(-28)). In addition, we confirmed the previous GWAS-identified locus at 17p13.1 for testosterone (rs2075230, p=1.13×10(-8)) and SHBG level (rs2075230, p=4.75×10(-19)) in the Chinese population. This study is the first GWAS investigation of genetic determinants of FSH and LH. The identification of novel susceptibility loci may provide more biological implications for the synthesis and metabolism of these hormones. More importantly, the confirmation of the genetic loci for testosterone and SHBG suggests common genetic components shared among different ethnicities.
    Journal of Medical Genetics 09/2013; DOI:10.1136/jmedgenet-2013-101705 · 5.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Increased serum uric acid (SUA) levels may be involved in the development of non-alcoholic fatty liver disease (NAFLD) in men presenting with metabolic syndrome (MetS) and/or insulin resistance. We aimed to determine the independent relationship between SUA and NAFLD in non-diabetic Chinese male population, and to explore the determinants of SUA levels among indexes of adiposity, lipid, and genotypes pertaining to triglycerides metabolism, inflammation, oxidative stress, and SUA concentrations. A total of 1440 men, classified depending on the presence of ultrasonographically detected NAFLD, underwent a complete healthy checkup program. Genotypes were extracted from our previously established genome-wide association study database. After adjusting for age, smoking, drinking, body mass index, homeostasis model assessment of insulin resistance, C-reactive protein, creatinine, alanine aminotransferase (ALT) and components of metabolic syndrome, the odds ratio for NAFLD, comparing the highest with the lowest SUA quartile, was 2.81 (95% confidence interval 1.66-4.76). A stepwise multivariate linear regression analysis (R(2) = 0.238, P<0.001) retained age, waist circumference, serum creatinine, triglycerides, the Q141K variant in ABCG2 (rs2231142) and NAFLD as significant predictors of SUA levels (all P<0.001). Besides, ALT and Met196Arg variant in TNFRSF1B (rs1061622) additionally associated with SUA among individuls with NAFLD. Our data suggest that in Chinese men, elevated SUA is significantly associated with NAFLD, independent of insulin resistance and other metabolic disorders, such as central obesity or hypertriglyceridemia. Meanwhile, among subjects with NAFLD, index of liver damage, such as elevated ALT combined with genetic susceptibility to inflammation associated with increased SUA levels.
    PLoS ONE 07/2013; 8(7):e67152. DOI:10.1371/journal.pone.0067152 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, an ionic liquid-based aqueous two-phase system (ATPs) has been developed for the effective extraction of bovine serum albumin (BSA). Compared with the effects of three different ionic liquids used in an aqueous two-phase system, a choline-like ionic liquid was selected as the suitable solution for bovine serum albumin. Extraction efficiencies of BSA were found to be dependant on the temperature, time, IL mass and the salt content. Based on single-factor experiments, these significant operating parameters of the ILs-ATP were respectively optimized. Experimental results show that 92.03–100.03% of the proteins could be extracted into the ionic liquid-rich phase in a single-step extraction. Repeatability, precision and stability experiments were investigated and the RSDs are lower than 2.3%, 1.7% and 4.7% respectively. Experiments indicated that intermolecular forces, the micelle phenomenon and the salting-out effect play important roles in the transfer process, and the aggregation phenomenon was the main driving force for the separation. Conformation of the protein was not affected after extraction into the upper ionic liquid-rich phase according to the determination by UV-visible (UV-vis), fluorescence spectra, dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy and TEM. It is suggested that the method of choline-like ILs-based ATPs for the selective separation of protein would have potential applications in bio-analysis and bio-separation.
    Analytical methods 06/2013; 5(13):3395-3402. DOI:10.1039/C3AY40377G · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: The goal of present study was to examine the influence of demographic characteristics, lifestyle, and metabolic factors on pressure-induced pain threshold. DESIGN AND SETTING: The study population comprised 2,517 healthy men at second-phase recruitment of a population-based cohort in China. The pressure pain threshold (PPT) at two locations, triceps and inguinal lines, was obtained using a digital pressure algometer. Education and occupation, as well as lifestyle factors, were self-reported in a face-to-face interview. Blood lipid and fasting glucose were measured as a routine healthy check-up program. RESULTS: A lower PPT was found among men with younger age, higher level of education, and non-manual occupation. In addition, men with central obesity and moderate leisure time physical exercise were more sensitive to muscle mechanical stimuli. PPT was significantly correlated with high-density lipoprotein cholesterol (β for triceps = 0.064, and β for inguinal lines = 0.052) in a multivariate linear regression model, after controlling for multiple variables. Elevated PPT was also found among subjects with hyperglycemia (both P for triceps and inguinal lines <0.001) and excess drinking (P for triceps = 0.005). CONCLUSIONS: It is important for physicians and researchers to consider these variables when evaluating pain sensitivity in clinic and in research. The underling mechanisms between these factors and pressure pain perception are worthy of further exploration.
    Pain Medicine 06/2013; 14(9). DOI:10.1111/pme.12158 · 2.24 Impact Factor
  • Journal of Convergence Information Technology 05/2013; 8(9):1052-1060. DOI:10.4156/jcit.vol8.issue9.128
  • 04/2013; 5(8):464-471. DOI:10.4156/ijact.vol5.issue8.52
  • International Journal of Digital Content Technology and its Applications 04/2013; 7(8):148-156. DOI:10.4156/jdcta.vol7.issue8.16
  • 04/2013; 5(7):204-212. DOI:10.4156/aiss.vol5.issue7.25
  • Journal of Convergence Information Technology 02/2013; 8(4):627-635. DOI:10.4156/jcit.vol8.issue4.72
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To explore the distribution characteristics of leukocytes in expressed prostatic secretions (EPS) in a large Chinese male population and the correlation with leukocytes and prostate-specific antigen (PSA) levels. From September to December 2009, EPS specimens were collected from 2504 men (age 20-69 years) who had undergone prostatic massage and were recruited from a large-scale community-based population survey in Southern China. The EPS specimens were divided into 5 categories according to the leukocyte count. The lifestyle and demographic characteristics were obtained by questionnaire. Asymptomatic and symptomatic men were defined according to the findings from the National Institutes of Health-Chronic Prostatitis Symptom Index questionnaire. EPS specimens were successfully collected from 1779 of the 2504 participants (71%). The degree of inflammation in the EPS specimens progressively increased with age, education, and body mass index (P <.001 for trend for all). A similar result was observed for men living with a partner compared with those living alone (P <.001) but not for men who smoked (P = .084) or consumed alcohol (P = .461). Moreover, a trend for PSA levels increasing progressively across leukocyte categories was observed (P <.001). The PSA levels were greater in all participants with inflammation than in those without (P <.001 for all) when inflammation was defined at 5+, 10+, and 20+ but not for 20+ in asymptomatic men and or not for 5+ and 10+ in symptomatic men. The results of the present study have shown that the degree of inflammation in EPS progressively increases with increasing age, body mass index, and education. Moreover, an increase of leukocytes in the EPS specimen correlated with increasing PSA levels. Prospective studies are needed to determine whether the minor elevations have clinical significance for prostatitis assessment.
    Urology 02/2013; 81(2):384-9. DOI:10.1016/j.urology.2012.11.001 · 2.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Prostate-specific antigen (PSA) is a commonly used cancer biomarker for prostate cancer, and is often included as part of routine physical examinations in China. Serum levels of PSA may be influenced by genetic factors as well as other factors. A genome-wide association study (GWAS) conducted in a European population successfully identified six genetic loci that were significantly associated with PSA level. In this study, we aimed to identify common genetic variants that are associated with serum level of PSA in a Chinese population. We also evaluated the effects of those variants by creating personalized PSA cutoff values. A two-stage GWAS of PSA level was performed among men age 20-69 years and self-reported cancer-free participants that underwent routine physical examinations at several hospitals in Guangxi Province, China. Single nucleotide polymorphisms (SNPs) significantly associated with PSA levels in the first stage of sample (N = 1,999) were confirmed in the second stage of sample (N = 1,496). Multivariate linear regression was used to assess the independent contribution of confirmed SNPs and known covariates, such as age, to the level of PSA. SNPs in three regions were significantly associated with levels of PSA in this two-stage GWAS, and had combined P values between 4.62 × 10(-17) and 6.45 × 10(-37). The three regions are located on 1q32.1 at SLC45A3, 10q11.23 at MSMB, and 19q13.33 at KLK3. The region 1q32.1 at SLC45A3 was identified as a novel locus. Genetic variants contributed significantly more to the variance of PSA level than known covariates such as age. Personalized cutoff values of serum PSA, calculated based on the inheritance of these associated SNPs, differ considerably among individuals. Identification of these genetic markers provides new insight into the molecular mechanisms of PSA. Taking individual variation into account, these genetic variants may improve the performance of PSA to predict prostate cancer.
    Human Genetics 12/2012; DOI:10.1007/s00439-012-1254-3 · 4.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Microfluidic PCR implements the PCR as a continuous process for nucleic acid analytics. Main fields of application are the monitoring of continuous processes for rapid identification of contaminants and quality control as well as high throughput screening of cells or microorganisms. The special heater arrangement allows the implementation of up to 40 cycles on the footprint of a sample. Precise temperature control is the key factor of PCR instrument, and optimal algorithm occupies an important position in this instrument. In order to optimizing the microfluidic PCR system thermal cycler perfomants, fuzzy-PID algorithm was designed, which would replace the lead correction algorithm. The simulation model was constructed and experimented with the use of the Simulink of Matlab software. The simulation results show that overshoot of lead correction algorithm is 8.5%, adjustment time is 3.4s. Overshoot of fuzzy-PID algorithm is 1.45%, adjustment time is only 1.94 s. Obviously, fuzzy-PID algorithm would overcome the defect of large overshoot of traditional PID, and the adjustment time becomes shorter also.
    Applied Mechanics and Materials 12/2012; 263-266:713-717. DOI:10.4028/www.scientific.net/AMM.263-266.713
  • Journal of Convergence Information Technology 09/2012; 7(17):364-372. DOI:10.4156/jcit.vol7.issue17.43
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Complement C3 and C4 play key roles in the main physiological activities of complement system, and their deficiencies or over-expression are associated with many clinical infectious or immunity diseases. A two-stage genome-wide association study (GWAS) was performed for serum levels of C3 and C4. The first stage was conducted in 1,999 healthy Chinese men, and the second stage was performed in an additional 1,496 subjects. We identified two SNPs, rs3753394 in CFH gene and rs3745567 in C3 gene, that are significantly associated with serum C3 levels at a genome-wide significance level (P = 7.33×10(-11) and P = 1.83×10(-9), respectively). For C4, one large genomic region on chromosome 6p21.3 is significantly associated with serum C4 levels. Two SNPs (rs1052693 and rs11575839) were located in the MHC class I area that include HLA-A, HLA-C, and HLA-B genes. Two SNPs (rs2075799 and rs2857009) were located 5' and 3' of C4 gene. The other four SNPs, rs2071278, rs3763317, rs9276606, and rs241428, were located in the MHC class II region that includes HLA-DRA, HLA-DRB, and HLA-DQB genes. The combined P-values for those eight SNPs ranged from 3.19×10(-22) to 5.62×10(-97). HBsAg-positive subjects have significantly lower C3 and C4 protein concentrations compared with HBsAg-negative subjects (P<0.05). Our study is the first GWAS report which shows genetic components influence the levels of complement C3 and C4. Our significant findings provide novel insights of their related autoimmune, infectious diseases, and molecular mechanisms.
    PLoS Genetics 09/2012; 8(9):e1002916. DOI:10.1371/journal.pgen.1002916 · 8.17 Impact Factor
  • 08/2012; 4(15):50-57. DOI:10.4156/aiss.vol4.issue15.6
  • [Show abstract] [Hide abstract]
    ABSTRACT: Methyl helicterate is a triterpenoid isolated from Helicteres angustifolia (Sterculiaceae), one of the valuable traditional Chinese herbs. Antifibrotic activities of H. angustifolia have been extensively proved. The purpose of this study was to investigate the effect of methyl helicterate (MH) on liver fibrosis in rats induced by carbon tetrachloride (CCl(4)) and to explore its underlying mechanism. Hepatic fibrosis was induced in male Sprague-Dawley (SD) rats by intragastric administration with 2ml/kg CCl(4) (mixed 1:1 in peanut oil) twice a week for 12 weeks. To evaluate the effect of MH (16.72, 33.45, 66.90mg/kg) on hepatic fibrosis, liver function, histological study and hepatic fibrosis evaluation were performed. Liver function was assessed by determining the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb) and total protein (TP). The biomarkers such as hydroxyproline (Hyp), hyaluronic acid (HA), type III precollagen (PCIII) and laminin (LN) were examined for the evaluation of hepatic fibrosis. The underlying mechanism was investigated by measuring oxidative stress level and detecting the expression of TGF-β1 mRNA and Smad3 protein. MH (33.45, 66.90mg/kg) treatment significantly inhibited the loss of body weight and the increase of liver index in rats induced by CCl(4). MH also improved the liver function as indicated by decreasing serum enzymatic activities of ALT, AST, TP and Alb (P<0.05). Histological results indicated that MH alleviated liver damage and reduced the formation of fibrous septa. Moreover, MH significantly decreased liver Hyp, HA, LN and PCIII (P<0.05). Research on mechanism showed that MH could markedly reduce liver malondialdehyde (MDA) concentration, increase activities of liver superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and inhibit the expression of TGF-β1 mRNA and Smad3 protein (P<0.05). Our findings indicated that MH can inhibit CCl(4)-induced hepatic fibrosis, which may be ascribed to its radical scavenging action, antioxidant activity, and modulation of TGF-β-Smad3 signaling pathway.
    Journal of ethnopharmacology 08/2012; 143(3):889-95. DOI:10.1016/j.jep.2012.08.018 · 2.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Vitamin B12 (VitB12 or cobalamin) is an essential cofactor in several metabolic pathways. Clinically, VitB12 deficiency is associated with pernicious anemia, neurodegenerative disorder, cardiovascular disease and gastrointestinal disease. Although previous genome-wide association studies (GWAS) identified several genes, including FUT2, CUBN, TCN1 and MUT, that may influence VitB12 levels in European populations, common genetic determinants of VitB12 remain largely unknown, especially in Asian populations. Here we performed a GWAS in 1999 healthy Chinese men and replicated the top findings in an independent Chinese sample with 1496 subjects. We identified four novel genomic loci that were significantly associated with serum level of VitB12 at a genome-wide significance level of 5.00 × 10(-8). These four loci were MS4A3 (11q12.1; rs2298585; P= 2.64 × 10(-15)), CLYBL (13q32; rs41281112; P= 9.23 × 10(-10)), FUT6 (19p13.3; rs3760776; P= 3.68 × 10(-13)) and 5q32 region (rs10515552; P= 3.94 × 10(-8)). In addition, we also confirmed the association with the serum level of VitB12 for the previously reported FUT2 gene and identified one novel non-synonymous single-nucleotide polymorphism in FUT2 gene in this Chinese population (19q13.33; rs1047781; P= 3.62 × 10(-36)). The new loci identified offer new insights into the biochemical pathways involved in determining the serum level of VitB12 and provide opportunities to better delineate the role of VitB12 in health and disease.
    Human Molecular Genetics 03/2012; 21(11):2610-7. DOI:10.1093/hmg/dds062 · 6.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: To examine the association of endogenous sex hormones and SHBG with C-reactive protein (CRP) in Chinese men. DESIGN AND PARTICIPANTS: The study population comprised 1989 men at baseline recruitment of a population-based cohort in China. Participant information on risk factors was collected by a face-to-face interview and clinical examination. All subjects in the study were without taking any kind of medication for anti-inflammation purpose or treatment of hypogonadism and with CRP value less than 10 mg/L. Data were analyzed by using linear regression analyses. RESULTS: Higher levels of total testosterone (TT, β = -0.114, 95%CI, -0.162 to -0.065), free testosterone (β = -0.059, 95%CI, -0.106 to -0.012) and SHBG (β = -0.116, 95%CI, -0.169 to -0.063) were statistically significantly related to lower levels of CRP, after adjustment for age, waist circumference (WC), triglycerides, high-density lipoprotein cholesterol, fasting glucose, insulin, smoking status, hypertension, diabetes and family history of hypertension or diabetes. In the subgroup of men with body mass index ≥27.5 kg/m(2) or with metabolic syndrome, findings for TT and SHBG were more pronounced, whereas the associations of TT with CRP were attenuated and nonstatistically significant among subjects with WC ≥90 cm or with insulin resistance. No associations were observed between estradiol, LH, FSH and CRP. CONCLUSIONS: We have confirmed the association of androgens with reduced inflammation as measured by CRP in Chinese men. This is independent of conventional cardiovascular risk factors and was explained in part by markers of central obesity and insulin resistance, rather than metabolic syndrome. © 2012 Blackwell Publishing Ltd.
    Clinical Endocrinology 02/2012; 78(1). DOI:10.1111/j.1365-2265.2012.04359.x · 3.35 Impact Factor

Publication Stats

66 Citations
52.35 Total Impact Points

Institutions

  • 2012–2014
    • China Agriculture University-East
      Peping, Beijing, China
    • Guilin Medical University
      Ling-ch’uan, Guangxi Zhuangzu Zizhiqu, China
  • 2013
    • Hunan University
      • College of Chemistry and Chemical Engineering
      Ch’ang-sha-shih, Hunan, China
  • 2012–2013
    • Guangxi Medical University
      • School of Public Health
      Yung-ning, Guangxi Zhuangzu Zizhiqu, China
  • 2011
    • Fudan University
      • Fudan-VARI Center for Genetic Epidemiology
      Shanghai, Shanghai Shi, China