keyword
MENU ▼
Read by QxMD icon Read
search

negative

keyword
https://www.readbyqxmd.com/read/28738648/matrix-interference-evaluation-employing-gc-and-lc-coupled-to-triple-quadrupole-tandem-mass-spectrometry
#1
S Uclés, A Lozano, A Sosa, P Parrilla Vázquez, A Valverde, A R Fernández-Alba
Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the "matrix effect", which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738638/mixed-matrix-membranes-incorporated-with-ln-mof-for-selective-and-sensitive-detection-of-nitrofuran-antibiotics-based-on-inner-filter-effect
#2
Feng Zhang, Hua Yao, Yifan Zhao, Xing Li, Gaowei Zhang, Yangyi Yang
The detection of antibiotics is critical and challenging due to the pervasive use of antibiotics had inevitably brought some negative impacts on ecosystem and human health. Herein, we reported an anti-interfere ability enhanced luminescent sensor of lanthanide metal-organic framework (Ln-MOF) filled mixed matrix membranes (MMMs), which combining the processibility of poly(methyl methacrylate) (PMMA) polymer with Ln-MOF of {[Tb2(AIP)2(H2O)10]·(AIP)·4H2O}n (Tb-AIP, where AIP is 5-aminoisophthalate) fillers...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738607/novel-colorimetric-assay-for-paraquat-detection-on-silica-bead-using-negatively-charged-silver-nanoparticles
#3
Weena Siangproh, Thachkorn Somboonsuk, Orawan Chailapakul, Kriangsak Songsrirote
A simple, rapid, sensitive, and economical method based on colorimetry for the determination of paraquat, a widely used herbicide, was developed. Citrate-coated silver nanoparticles (AgNPs) were synthesized as the colorimetric probe. The mechanism of the assay is related to the aggregation of negatively charged AgNPs as induced by positively-charged paraquat resulting from coulombic attraction which causes the color to change from a deep greenish yellow to pale yellow in accordance with the concentrations of paraquat...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738592/a-unique-red-emitting-two-photon-fluorescent-probe-with-tumor-specificity-for-imaging-in-living-cells-and-tissues
#4
Xiuqi Kong, Baoli Dong, Nan Zhang, Chao Wang, Xuezhen Song, Weiying Lin
Tumor-specific imaging can provide an attractive approach for the early detection and prognosis of cancer, as well as the precise image-guided tumor-removal surgery. Herein, we describe a unique red-emitting two-photon fluorescent probe (N-BN) for tumor-specific imaging. N-BN utilized Nile Red as the red-emitting two-photon fluorophore and employed biotin as the tumor-specific ligand. In the presence of a variety of biomolecules or in different pH buffers, the fluorescence intensity of N-BN at 655nm showed no noticeable change...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738586/development-of-a-solid-phase-extraction-method-with-simple-mekc-uv-analysis-for-simultaneous-detection-of-indole-metabolites-in-human-urine-after-administration-of-indole-dietary-supplement
#5
Apichai Phonchai, Prapin Wilairat, Rattikan Chantiwas
This work presents the development of a solid phase extraction method with simple MEKC-UV analysis for the simultaneous determination of indole-3-carbinol (I3C) and its metabolites (3, 3'-diindolylmethane (DIM), indole-3-carboxaldehyde (I3CAL), indole-3-acetonitrile (I3A)) in human urine after oral administration of an indole dietary supplement. Solid phase extraction (SPE) method was applied for the first time for simultaneous analysis of these indole metabolites. The MEKC separation method was developed in a previous work...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738582/metaboqc-a-tool-for-correcting-untargeted-metabolomics-data-with-mass-spectrometry-detection-using-quality-controls
#6
Mónica Calderón-Santiago, María A López-Bascón, Ángela Peralbo-Molina, Feliciano Priego-Capote
Nowadays most metabolomic studies involve the analysis of large sets of samples to find a representative metabolite pattern associated to the factor under study. During a sequence of analyses the instrument signals can be subjected to the influence of experimental variability sources. Implementation of quality control (QC) samples to check the contribution of experimental variability is the most common approach in metabolomics. This practice is based on the filtration of molecular entities experiencing a variation coefficient higher than that measured in the QC data set...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738561/silver-triangular-nanoplates-as-an-high-efficiently-fret-donor-acceptor-of-upconversion-nanoparticles-for-ultrasensitive-turn-on-off-protamine-and-trypsin-sensor
#7
Hongyu Chen, Aijin Fang, Youyu Zhang, Shouzhuo Yao
Silver triangular nanoplates (STNPs) as a high efficient fluorescence quenching reagent of upconversion nanoparticles (UCNPs) was used to constract a novel label-free fluorescence nanosensor for ultrasensitive detection of protamine and trypsin based on fluorescence resonance energy transfer (FRET) between STNPs and UCNPs. In this assay, the negatively charged STNPs can bind with positively charged UCNPs through electrostatic interaction, and then quenched the fluorescence of UCNPs. When protamine was added to the mixture of UCNPs-STNPs, the STNPs interacted with protamine and then detached from the surface of UCNPs and aggregated, which result in the recovery of the fluorescence of UCNPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738534/high-expression-of-cd47-predicts-adverse-prognosis-in-chinese-patients-and-suppresses-immune-response-in-melanoma
#8
Wenhua Fu, Jisen Li, Wei Zhang, Peng Li
BACKGROUND: Cluster of differentiation 47 (CD47) negatively regulates macrophage phagocytosis and is correlated with adverse survival of multiple cancers. In melanoma patients, especially in Chinese melanoma patients, its prognostic value is unclear. In this study, we aim to study the prognostic value of CD47 in a Chinse melanoma patient cohort and its immunomodulation roles in mouse model. METHOD: 164 melanoma tissue specimens were collected. The expression of CD47 in these clinical samples was examined by immunohistochemistry staining (IHC)...
July 20, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28738533/mir-200a-expression-in-cd4-t-cells-correlates-with-the-expression-of-th17-treg-cells-and-relevant-cytokines-in-psoriasis-vulgaris-a-case-control-study
#9
Xiao-Yan Wang, Xing-Yu Chen, Jun Li, Hong-Ying Zhang, Juan Liu, Le-Dong Sun
The main aim of this study is to investigate the underlying relationship shared between microRNA-200a (miR-200a) and its link to concentrations of Th17 and Treg cells, mRNA expressions of their specific transcription factors retinoic acid-related orphan receptor γt (RORγt) and head box protein 3 (FOXP3) and relevant cytokines in patients with psoriasis vulgaris (PV). A total of 189 patients previously diagnosed with PV were selected as the experimental group, whilst 109 healthy individuals as the control group...
July 20, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28738531/surface-complexation-modeling-of-cu-ii-sorption-to-montmorillonite-bacteria-composites
#10
Chengcheng Qu, Mingkai Ma, Wenli Chen, Peng Cai, Qiaoyun Huang
Surface complexation modeling, isothermal titration calorimetry, and batch adsorption were employed to characterize the adsorption of Cu onto montmorillonite, Pseudomonas putida X4, and their composites at mass ratios of 2:1, 6:1, and 12:1, respectively. Different enthalpy values were found for Cu adsorption to permanent (-6.43kJ/mol) and variable charge sites (8.51kJ/mol) on montmorillonite. The component additivity (CA) method was used to predict the adsorption of Cu on the composites by combining end member models for montmorillonite and P...
July 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738512/effects-of-nitrogen-deposition-on-soil-microbial-communities-in-temperate-and-subtropical-forests-in-china
#11
Di Tian, Lai Jiang, Suhui Ma, Wenjing Fang, Bernhard Schmid, Longchao Xu, Jianxiao Zhu, Peng Li, Gianalberto Losapio, Xin Jing, Chengyang Zheng, Haihua Shen, Xiaoniu Xu, Biao Zhu, Jingyun Fang
Increasing nitrogen (N) deposition has aroused large concerns because of its potential negative effects on forest ecosystems. Although microorganisms play a vital role in ecosystem carbon (C) and nutrient cycling, the effect of N deposition on soil microbiota still remains unclear. In this study, we investigated the responses of microbial biomass C (MBC) and N (MBN) and microbial community composition to 4-5years of experimentally simulated N deposition in temperate needle-leaf forests and subtropical evergreen broadleaf forests in eastern China, using chloroform fumigation extraction and phospholipid fatty acid (PLFA) methods...
July 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738498/microrna-299-3p-suppresses-proliferation-and-invasion-by-targeting-vegfa-in-human-colon-carcinoma
#12
Jia-Yong Wang, Jin-Bo Jiang, Yuan Li, Yan-Lei Wang, Yong Dai
Accumulating evidences have shown that microRNAs (miRNAs) are vital regulators and possess huge capabilities in post-transcriptional control. Although a large number of miRNAs have been identified to be dysregulated in human cancers especially in colon cancer, our understandings of the function of most miRNAs are still largely limited. In this study, we have demonstrated that miR-299-3p plays a critical role in suppressing colon carcinoma progression by targeting Vascular Endothelial Growth Factor A (VEGFA)...
July 18, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28738484/-correlation-between-serum-inflammatory-cytokine-levels-and-fibrous-cap-thickness-of-fibrofatty-plaque-in-coronary-culprit-lesions
#13
Y Zhong, F Ye, W You, Z M Wu
Objective: To identify the correlation between serum inflammatory cytokine levels including high sensitive C reactive protein (hs-CRP) and lipoprotein associated phospholipase (Lp-PLA2) and the fibrous cap thickness of fibrofatty plaque in coronary culprit lesions. Methods: Clinical data of 117 patients with selective coronary artery angiography diagnosed coronary artery disease admitted to our hospital from January 2015 to January 2016 were retrospective analyzed. According to type of coronary disease, patients were divided into 3 subgroups: SAP group (containing 47 stable angina patients), UAP group (containing 52 unstable angina patients), and NSTEMI group(containing 18 acute non ST segment elevation myocardial infarction patients)...
July 24, 2017: Zhonghua Xin Xue Guan Bing za Zhi
https://www.readbyqxmd.com/read/28738472/-effect-of-interleukin-6-and-interleukin-12-on-immune-response-to-hepatitis-b-vaccination-in-infants-of-hbsag-positive-mothers
#14
X F Wang, X H Shi, X X Xu, Z Q Yang, H Y Hao, F Zhang, B Wang, H X Wen, Z D Fu, T Wang, S Y Feng, B Wang, S P Wang
Objective: To explore the effect of interleukin-6 (IL-6) and Interleukin-12 (IL-12) on immune response to hepatitis B vaccination in infants of HBsAg-positive mothers. Methods: A total of 91 neonates whose mothers were HBsAg-positive were included and followed up for 12 months. HBV DNA and HBV serological markers in the peripheral blood of the neonates and infants were detected with fluorescence quantitative polymerase chain reaction (FQ-PCR) and chemiluminescence immunoassay (CLIA), and the levels of IL-6 and IL-12 in the peripheral blood of the neonates and infants were detected with enzyme-linked immunosorbent assay (ELISA)...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738471/-association-between-phage-mediated-shiga-toxin-and-molecular-distribution-of-crispr-in-escherichia-coli-o26-%C3%A2-h11-or-nm
#15
J Z Long, Y K Xu, G C Duan, W J Liang, H Y Liu, S Y Chen, Y L Xi, P F Wang, Y F Wang
Objective: To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26∶H11 or NM. Methods: A total of 135 E. coli O26 ∶ H11 or NM strains were collected from NCBI database. Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR. And the relationship between CRISPR and stx phage was analyzed. Results: All the 135 E. coli O26 ∶ H11 or NM strains had the CRISPR...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738469/-analysis-on-geographic-distribution-of-high-blood-pressure-prevalence-in-children-and-adolescents-aged-7-18-years-in-china-2014
#16
Y H Dong, Z Y Zou, Z H Wang, S Wang, Z P Yang, Y J Chen, J Ma
Objective: To understand and evaluate the characteristics of geographic distribution of high blood pressure prevalence in children and adolescents aged 7-18 years in China in 2014, and provide evidence for the prevention of hypertension in children and adolescents. Methods: The data of 2014 Chinese National Surveys on Students Constitution and Health conducting 31 provinces (except Hong Kong, Macao and Taiwan) were collected. A total of 216 299 children and adolescents who had complete blood pressure records were selected as study subjects...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738466/-a-large-scale-cohort-study-on-aids-in-communities-in-dali-yunnan-province-2014-2015
#17
M Y Xiao, X M Chen, Y L Ma, L R Fu, J Niu, Z J Chen, H Y Li, Q L Wang, L J Song, H B Luo
Objective: To understand HIV incidence in community residents and epidemiological characteristics of newly detected HIV infection cases in Dali, Yunnan province. Methods: A cohort study was conducted among 146 720 community residents who were tested to be HIV negative during 2010-2011, they were followed-up from June 1, 2014 to May 31, 2015. Results: A total of 136 356 community residents received follow up (92.9%). The follow-up time was 0.23-5.40 years (medium: 3.43 years), cumulatively 459 675 person years, and 78 people were found to be HIV positive...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738465/-influencing-factors-for-non-low-response-to-hepatitis-b-vaccine-in-infants-of-hbsag-positive-mothers
#18
B Wang, X X Xu, H X Wen, H Y Hao, Z Q Yang, X H Shi, Z D Fu, X F Wang, F Zhang, B Wang, S P Wang
Objective: To investigate the influencing factors for non/low-response to hepatitis B vaccine in infants of HBsAg-positive mothers. Methods: A total of 286 HBsAg-positive pregnant women and their infants were recruited from the Third People's Hospital of Taiyuan during July 2011 to January 2013. The infants were immunized with hepatitis B vaccine according to the 0-1-6 month vaccination schedule and followed up for 12 months. The serum HBV DNA level of mothers, neonates and infants were detected by electro chemilum inescence immunoassay kits and fluorescene quantiative polymerase chain rection...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738460/-association-between-sleep-and-leukocyte-telomere-length-in-middle-aged-and-older-adults
#19
H F Liu, F Li, Y H Wang, J H Chen, D X Peng, J Chen, L H Tan, X Mi, B H Zhao
Objective: To understand the association between peripheral leukocytes telomere length (TL) and sleep in middle-aged and old adults. Methods: A total of 176 middle-aged and old adults were investigated by using the Pittsburgh Sleep Quality Index and questionnaire. TL was measured by fluorescence quantitative PCR. The correlation and regression analysis between sleep and telomere length was performed. Results: TL had a mean T/S ratio of 0.995±0.23. There was a negative correlation between TL and age (r=-0.241, P=0...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738454/-development-of-markov-models-for-economics-evaluation-of-strategies-on-hepatitis-b-vaccination-and-population-based-antiviral-treatment-in-china
#20
P C Yang, S X Zhang, P P Sun, Y L Cai, Y Lin, Y H Zou
Objective: To construct the Markov models to reflect the reality of prevention and treatment interventions against hepatitis B virus (HBV) infection, simulate the natural history of HBV infection in different age groups and provide evidence for the economics evaluations of hepatitis B vaccination and population-based antiviral treatment in China. Methods: According to the theory and techniques of Markov chain, the Markov models of Chinese HBV epidemic were developed based on the national data and related literature both at home and abroad, including the settings of Markov model states, allowable transitions and initial and transition probabilities...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
keyword
keyword
85707
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"