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1.
Article in English | MEDLINE | ID: mdl-36868497

ABSTRACT

BACKGROUND: Internet addiction (IA) is a behavioral addiction to problematic internet use. IA is associated with poorer sleep quality. Few studies to date, however, have explored the interactions between symptoms of IA and symptoms of sleep disturbance. This study uses network analysis to identify bridge symptoms by analyzing these interactions in a large sample of students. METHOD: We recruited 1977 university students to participate in our study. Each student completed the Internet Addiction Test (IAT) and the Pittsburgh Sleep Quality Index (PSQI). We used these collected data for network analysis to identify the bridge symptoms in the IAT-PSQI network by calculating the bridge centrality. Furthermore, the closest symptom connected with the bridge symptom was found to identify the comorbidity mechanisms. RESULTS: The core symptom of IA and the sleep disturbance network was "I08" (Study efficiency suffers due to internet use). The bridge symptoms between IA and sleep disturbance were "I14" (Surfing the internet late instead of sleeping), "P_DD" (Daytime dysfunction), and "I02" (Spending much time online instead of socializing in real life). Among the symptoms, "I14" had the highest bridge centrality. The edge connecting nodes "I14" and "P_SDu" (Sleep duration) had the strongest weight (0.102) around all the symptoms of sleep disturbance. Nodes "I14" and "I15" (Thinking about online shopping, games, social networking, and other network activities when unable to access the internet) had the strongest weight (0.181), connecting all the symptoms of IA. CONCLUSIONS: IA leads to poorer sleep quality, most likely by shortening sleep duration. Preoccupation with and craving the internet while being offline may lead to this situation. Healthy sleep habits should be learned, and craving may be a good point at which to treat the symptoms of IA and sleep disturbance.


Subject(s)
Behavior, Addictive , Sleep Initiation and Maintenance Disorders , Sleep Wake Disorders , Humans , Internet Addiction Disorder/epidemiology , Students , Comorbidity , Sleep , Behavior, Addictive/complications , Behavior, Addictive/diagnosis , Sleep Wake Disorders/complications , Sleep Wake Disorders/epidemiology , Internet
2.
J Med Internet Res ; 24(11): e38984, 2022 11 10.
Article in English | MEDLINE | ID: mdl-36355402

ABSTRACT

BACKGROUND: An increasing number of people are becoming addicted to the internet as a result of overuse. The Internet Addiction Test (IAT) is a popular tool for evaluating internet use behaviors. The interaction between different symptoms and the relationship between IAT and clinical diagnostic criteria are not well understood. OBJECTIVE: This study aimed to explore the core symptoms of internet addiction (IA) and the correlation between different symptoms of the IA symptom network. Network analysis was also conducted to explore the association between the IAT scale and the Diagnostic and Statistical Manual of Mental Disorders-5th edition (DSM-5) criteria for IA. METHODS: We recruited 4480 internet users (aged 14-24 years), and they completed the IAT. The final analysis included 63.50% (2845/4480) of the participants after screening the submitted questionnaires. Participants were classified into IA group and non-IA (NIA) group. By using partial correlation with Lasso regularization networks, we identified the core symptoms of IA in each group and compared the group differences in network properties (strength, closeness, and betweenness). Then, we analyzed the symptom networks of the DSM-5 diagnostic criteria and IAT scale for IA. RESULTS: A total of 12.47% (355/2845) of the patients were in the IA group and 87.52% (2490/2845) of the patients were in the NIA group, and both groups were evaluated for the following nodes: IAT_06 (school work suffers; strength=0.511), IAT_08 (job performance suffers; strength=0.531), IAT_15 (fantasize about being on the web; strength=0.474), IAT_17 (fail to stop being on the web; strength=0.526), and IAT_12 (fear about boredom if offline; strength=0.502). The IA groups had a stronger edge between IAT_09 (defensive or secretive about being on the web) and IAT_18 (hidden web time) than the NIA groups. The items in DSM-5 had a strong association with IAT_12 (weight=-0.066), IAT_15 (weight=-0.081), IAT_17 (weight=-0.106), IAT_09 (weight=-0.198), and IAT_18 (weight=-0.052). CONCLUSIONS: The internet use symptom network of the IA group is significantly different from that of the NIA group. Nodes IAT_06 (school work affected) and IAT_08 (work performance affected) are the resulting symptoms affected by other symptoms, whereas nodes IAT_12 (fear about boredom if offline), IAT_17 (inability to stop being on the web), and IAT_15 (fantasize about being on the web) are key symptoms that activate other symptoms of IA and are strongly linked to the inability to control the intention to play games in the DSM-5.


Subject(s)
Behavior, Addictive , Humans , Behavior, Addictive/diagnosis , Surveys and Questionnaires , Internet Addiction Disorder/diagnosis , Internet , Schools
3.
Am J Alzheimers Dis Other Demen ; 37: 15333175221091424, 2022.
Article in English | MEDLINE | ID: mdl-35442818

ABSTRACT

BACKGROUND: Alzheimer's disease (AD) is an age-related neurodegenerative disease and exercises might mitigate the progression of AD. This investigation aimed to manifest the potential mechanism of exercises in AD. METHODS: Morris water maze (MWM) test was conducted to evaluate the cognitive function in APP/PS1 mice. Quantitative real-time PCR was performed to detect the expression of HOTAIR and miR-130a-3p. The enzyme-linked immunosorbent assay was applied to appraise the concentration of IL-1ß, IL-6, and TNF-α. A luciferase report experiment was implemented to substantiate the relationship between miR-130a-3p and HOTAIR. RESULTS: Exercises contributed to the elevated expression of HOTAIR. The findings of MWM implied HOTAIR inhibited the impacts of voluntary exercises on escape latency, distance moved, percentage of time spent in the target quadrant, platform crossing times, and inflammation. MiR-130a-3p mediated the function of HOTAIR on cognitive ability and inflammation. CONCLUSION: HOTAIR participated in the regulation of exercises on AD by sponging miR-130a-3p.


Subject(s)
Alzheimer Disease , MicroRNAs , Neurodegenerative Diseases , RNA, Long Noncoding , Alzheimer Disease/genetics , Animals , Cognition , Humans , Inflammation/genetics , Mice , MicroRNAs/genetics , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism
4.
Brain Behav ; 12(3): e2510, 2022 03.
Article in English | MEDLINE | ID: mdl-35114077

ABSTRACT

BACKGROUND: Internet addiction (IA), which is disadvantageous for decision making, such as moral judgment, is a pernicious threat to contemporary societies. However, few studies consider social cognition abilities as an important variable in IA. OBJECTIVES: This study explores the psychological mechanism of IA facing the moral dilemma. METHODS: Forty participants with IA and 89 healthy participants were recruited. They finished the Internet Addiction Test and completed the moral judgment task. The process dissociation (PD) method and the consequences, norms, and generalized inaction (CNI) model were used to analyze moral judgment data. RESULTS: Compared with the healthy control (HC) group, the traditional analysis showed that the IA group made more utilitarian judgment regarding moral dilemmas. PD analysis showed that the IA group had decreased deontological inclination, without utilitarian inclination. The CNI model further showed that the sensitivity of the IA group to moral rules was significantly lower than that of the HC group, while there was no significant difference between groups in the sensitivity to the consequences and the general preference for action. CONCLUSIONS: Individuals with IA make more utilitarian judgment when faced with a moral dilemma, which is related to their weak sensitivity to moral norms.


Subject(s)
Ethical Theory , Judgment , Cognition , Humans , Internet Addiction Disorder , Morals
5.
Folia Neuropathol ; 60(4): 414-420, 2022.
Article in English | MEDLINE | ID: mdl-36734383

ABSTRACT

INTRODUCTION: Exercise is effective in Alzheimer's disease (AD), which is characterized by neuro-degenerative progress with increasing morbidity. The present study aimed to explore whether HOTAIR participated in the regulation of exercise in AD. MATERIAL AND METHODS: A relative expression of serum HOTAIR was detected using quantitative real-time polymerase chain reaction (PCR). The diagnostic significance of HOTAIR on distinguishing AD patients was evaluated by receiver operating characteristic (ROC) curve. Correlations between HOTAIR expression and Mini-Mental State Examination (MMSE) score or Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) score were analyzed with Pearson's test. Logistic regression analysis was applied to investigate factors as independent indicators for HOTAIR expression. RESULTS: In AD patients, the expression of HOTAIR was increased, and it could function as a diagnostic marker in AD patients. The expression of HOTAIR was associated with MMSE score and ADAS-Cog score in AD patients before exercise. Exercise ameliorated the cognitive impairment and reduced the relative serum expression of HOTAIR. Exercise was proved to be an independent indicator of HOTAIR expression. CONCLUSIONS: HOTAIR was a possible biomarker for indicating AD patients, and it was correlated with MMSE scores and ADAS-Cog results. Exercise might moderate AD progress via controlling HOTAIR.


Subject(s)
Alzheimer Disease , Cognitive Dysfunction , RNA, Long Noncoding , Humans , Alzheimer Disease/diagnosis , Alzheimer Disease/genetics , Biomarkers , Neuropsychological Tests , RNA, Long Noncoding/genetics
6.
Aging (Albany NY) ; 13(16): 20418-20437, 2021 08 23.
Article in English | MEDLINE | ID: mdl-34424219

ABSTRACT

PURPOSE: To determine the effect of Bu-Shen-Zhu-Yun Decoction (BSZY-D) on the kisspeptin through JAK2/STAT5 signaling pathway in hyperprolactinemia (HPRL) infertility. METHOD: SD rats were treated with BSZY-D for cerebrospinal fluid (CSF) extraction. GT1-7 cells were subjected to different treatments. The phosphorylation levels of JAK2 and STAT5, and the expressions of PRLR and kisspeptin of GT1-7 cells in different groups were detected by western blot, RT-qPCR and immunofluorescence. The expressions of CSN5 and GATA1 and other molecular features were checked by western blot, RT-PCR, co-immunoprecipitation and renilla luciferase activity. RESULTS: The phosphorylation levels of JAK2 and STAT5, and the expressions of PRLR and kisspeptin in the HPRL group were significantly decreased, and these changes could be reversed after BSZY-D treatment. In addition, the presence of PRLR deubiquitination was detected in the HPRL group, which could be reversed by shRNA-CSN5, suggesting that BSZY-D played a role through targeting CSN5. The binding level of GATA1 and CSN5 promoter in the HPRL group was significantly decreased, but elevated in the HPRL (BSZY-D/CSF) group (P < 0.05). CONCLUSION: BSZY-D improved the transcription activity of GATA1 and increased the binding of GATA1 and CSN5. BSZY-D was involved in the deubiquitination of PRLR, which contributes to alleviating the symptoms of HPRL infertility.


Subject(s)
COP9 Signalosome Complex/metabolism , Drugs, Chinese Herbal/administration & dosage , Hyperprolactinemia/drug therapy , Intracellular Signaling Peptides and Proteins/metabolism , Janus Kinase 2/metabolism , Prolactin/metabolism , STAT5 Transcription Factor/metabolism , Animals , COP9 Signalosome Complex/genetics , Female , GATA1 Transcription Factor/genetics , GATA1 Transcription Factor/metabolism , Humans , Hyperprolactinemia/genetics , Hyperprolactinemia/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Janus Kinase 2/genetics , Prolactin/genetics , Rats , Rats, Sprague-Dawley , STAT5 Transcription Factor/genetics , Signal Transduction/drug effects
7.
Int J Clin Exp Med ; 8(8): 12211-8, 2015.
Article in English | MEDLINE | ID: mdl-26550131

ABSTRACT

Sepsis is a serious infection-related complication that, in causing significant inflammation, often leads to myocardial injury. Severe inflammation, including in sepsis, is sometimes treated with exogenous glucocorticoids (GCs). Here, to explore the potential effect of GCs to protect against myocardial injury, we created a model of sepsis in rats by performing cecal ligation and puncture (CLP) in 96 rats randomly divided into sham-operated control (N=32), untreated sepsis (CLP, N=32), and GC-treated sepsis (N=32) groups. At 3, 6, 12, and 24 h after surgery, the changes in cardiac hemodynamic indexes, serum inflammatory response factor levels, and myocardial enzymes were measured, along with mitochondrial membrane potential in myocardial cells, apoptosis of myocardial cells, and the expression of nuclear factor kappa B (NF-κB p65) in myocardial tissues. Pathological changes in myocardial cells were also observed. Compared to the sham-operated group, CLP rats experienced deterioration of left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximum rate of left ventricular pressure rise (+dP/dtmax), and the maximum rate of left ventricular pressure drop (-dP/dtmax). CLP rats also had a rise in serum tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), cardiac troponin I (cTnI), creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and NF-κB p65 in myocardial tissues. The GCs-treated group had lower levels of these inflammatory response molecules than the CLP group, with the exception of anti-inflammatory cytokine interleukin-10 (IL-10), which was higher in the GC-treated rats than the CLP group at each time point post-surgery. Compared to the sham group, CLP rats had a rise in myocardial cell apoptosis and a drop in mitochondrial membrane potential in myocardial cells. In addition, GCs-treated rats had a marked drop in the myocardial cell apoptosis rate and a rise in the mitochondrial membrane potential compared to CLP rats. After intervention with GCs, the pathological changes in heart tissues were also reduced compared to those in the sepsis group. Based on these results, we conclude that exogenous GCs can inhibit a drop in myocardial mitochondrial membrane potential and inhibit myocardial cell apoptosis by blocking the activation of NF-κB, decreasing the generation of proinflammatory cytokines, and relieving inflammatory injury in heart tissues.

8.
Balkan Med J ; 31(1): 55-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-25207168

ABSTRACT

BACKGROUND: Recent studies have reported contrasting results regarding the association of polymorphisms in two integrin genes, ITGA2 and ITGB3, with ischemic stroke. AIMS: The present study aimed to investigate the correlation between the ITGA2 C807T and ITGB3 T176C polymorphic loci with ischemic stroke, as well as plasma lipid and lipoprotein levels. STUDY DESIGN: Case control study. METHODS: Human venous blood samples were collected from patients admitted for ischemic stroke (n=350, 'patients') and healthy individuals (n=300, 'controls'). Blood was genotyped at these loci by polymerase chain reaction-restriction fragment length polymorphism. Plasma lipid and lipoprotein levels were measured by routine enzymatic, masking, and turbidimetry methods. RESULTS: As expected, total cholesterol, triglycerides, and low-density lipoprotein were all significantly higher in patients than in controls (p<0.05). Genotype and allele frequencies of ITGA2 C807T were significantly different between patients and controls (p<0.05), but no difference was detected in genotype or allele frequencies for ITGA3 T176C. For ITGA-2, the T allele conferred a 1.226 times higher relative risk of ischemic stroke than the C allele (odds ratio=1.226, 95% confidence interval=1.053-1.428). Similarly, total cholesterol was higher in T allele carriers than in non-carriers (p<0.05). CONCLUSION: ITGA2 C807T polymorphism is associated with ischemic stroke, with the T allele acting as a susceptibility allele that appears to confer increased cholesterol levels.

9.
Braz. j. med. biol. res ; 46(6): 502-506, 02/jul. 2013. tab, graf
Article in English | LILACS | ID: lil-679204

ABSTRACT

Single nucleotide polymorphisms in the promoter region of interleukin-18 (IL-18), an inflammatory cytokine, have been linked to susceptibility to many diseases, including cancer and immune dysfunction. Here, we explored the potential association between the IL-18 -607C/A (rs1946518) promoter region polymorphism and susceptibility to ischemic stroke (IS). This locus was amplified from peripheral blood samples of 386 IS patients (cases) and 364 healthy individuals (controls) by the polymerase chain reaction with sequence-specific primers. Significant differences were observed by the χ2 test in the -607C/A (rs1946518) genotype and allele frequencies between cases and controls (P < 0.05). Furthermore, after excluding for age, gender, smoking status, and hypertension, logistic regression indicated that IS susceptibility of -607C carriers increased 1.6 times (OR = 1.601, 95%CI = 1.148-2.233, P = 0.006) compared to -607A carriers. Additionally, similar increases in IS risk were noted for male patients or patients less than 65 years old. In conclusion, IL-18 -607C/A (rs1946518) promoter polymorphism is associated with IS susceptibility, and the C allele may confer increased IS risk.


Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Brain Ischemia/genetics , /genetics , Polymorphism, Single Nucleotide , Promoter Regions, Genetic/genetics , Stroke/genetics , Brain Ischemia/epidemiology , Genotype , Genetic Predisposition to Disease/epidemiology , Polymerase Chain Reaction , Prospective Studies , Smoking , Stroke/epidemiology
10.
Braz J Med Biol Res ; 46(6): 502-6, 2013 06.
Article in English | MEDLINE | ID: mdl-23739747

ABSTRACT

Single nucleotide polymorphisms in the promoter region of interleukin-18 (IL-18), an inflammatory cytokine, have been linked to susceptibility to many diseases, including cancer and immune dysfunction. Here, we explored the potential association between the IL-18 -607C/A (rs1946518) promoter region polymorphism and susceptibility to ischemic stroke (IS). This locus was amplified from peripheral blood samples of 386 IS patients (cases) and 364 healthy individuals (controls) by the polymerase chain reaction with sequence-specific primers. Significant differences were observed by the χ2 test in the -607C/A (rs1946518) genotype and allele frequencies between cases and controls (P < 0.05). Furthermore, after excluding for age, gender, smoking status, and hypertension, logistic regression indicated that IS susceptibility of -607C carriers increased 1.6 times (OR = 1.601, 95%CI = 1.148-2.233, P = 0.006) compared to -607A carriers. Additionally, similar increases in IS risk were noted for male patients or patients less than 65 years old. In conclusion, IL-18 -607C/A (rs1946518) promoter polymorphism is associated with IS susceptibility, and the C allele may confer increased IS risk.


Subject(s)
Brain Ischemia/genetics , Interleukin-18/genetics , Polymorphism, Single Nucleotide , Promoter Regions, Genetic/genetics , Stroke/genetics , Adult , Aged , Brain Ischemia/epidemiology , Female , Genetic Predisposition to Disease/epidemiology , Genotype , Humans , Male , Middle Aged , Polymerase Chain Reaction , Prospective Studies , Smoking , Stroke/epidemiology
11.
Mol Med Rep ; 6(2): 371-4, 2012 08.
Article in English | MEDLINE | ID: mdl-22641427

ABSTRACT

Stroke is a leading cause of cardiovascular morbidity, economic and social burden and mortality. Novel approaches are needed to address stroke prevention and treatment. The purpose of this study was to explore the effects of aloe polysaccharide on caspase-3 expression following cerebral ischemia reperfusion injury in rats. Male Wistar rats were randomly divided into 5 groups (16 rats in each group): aloe polysaccharide, ginkgo leaf tablet, nimodipine, model and sham surgery groups. The rats were administered the appropriate drug or normal saline for 7 days by gavage. A rat model of cerebral ischemia and reperfusion injury was established using the middle cerebral artery occlusion (MCAO) model. Caspase-3 protein and mRNA expression levels in the cerebral cortex were detected by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Results showed that caspase-3 protein and mRNA expression levels in the cerebral cortex in the aloe polysaccharide, ginkgo leaf tablet and nimodipine groups were significantly lower compared with the model group and were higher than the sham surgery group (P<0.05). No significant difference was observed in caspase-3 protein and mRNA expression among the aloe polysaccharide, the ginkgo leaf tablet and the nimodipine groups (P>0.05). In conclusion, aloe polysaccharide has a protective effect on cerebral ischemia that may be due to the inhibition of neuronal cell apoptosis.


Subject(s)
Brain Ischemia/drug therapy , Caspase 3/metabolism , Gene Expression Regulation, Enzymologic , Phytotherapy , Polysaccharides/pharmacology , Reperfusion Injury/drug therapy , Aloe/chemistry , Animals , Brain Ischemia/enzymology , Brain Ischemia/pathology , Caspase 3/genetics , Cerebral Cortex/drug effects , Cerebral Cortex/enzymology , Cerebral Cortex/pathology , Ginkgo biloba/chemistry , Immunohistochemistry , Infarction, Middle Cerebral Artery/pathology , Infarction, Middle Cerebral Artery/surgery , Male , Models, Animal , Neurons/enzymology , Neurons/pathology , Neuroprotective Agents/administration & dosage , Neuroprotective Agents/pharmacology , Nimodipine/administration & dosage , Nimodipine/pharmacology , Plant Leaves/chemistry , Polysaccharides/administration & dosage , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Reperfusion Injury/enzymology , Reperfusion Injury/pathology , Reverse Transcriptase Polymerase Chain Reaction , Tablets/administration & dosage
12.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 26(8): 787-9, 2010 Aug.
Article in Chinese | MEDLINE | ID: mdl-21033036

ABSTRACT

AIM: to investigate the relation between the expression of ANXA2 in human glioma and its pathological grades, and research the possibility that if ANXA2 could be as a useful diagnostic marker for glioma. METHOD: Semi-quantity RT-PCR and immunohistochemistry were proceeded fro corresponding specimens to detect the level of ANXA2 and ANXA2mRNA. RESULTS: In RT-PCR, the expression level of ANXA2mRNA in glioma was higher than that in surrounding brain tissue. (P < 0.05), as the same, in immunohistochemistry, the expression level of ANXA2 in glioma is higher than that is surrounding brain tissues (P< 0.05). CONCLUSION: ANXA2 expression was much higher in glioma samples than in the surrounding brain tissues, and positive correlation between its expression and pathological grades was found. It could be used as an assistant diagnostic index for glioma.


Subject(s)
Annexin A2/genetics , Glioma/genetics , Adolescent , Adult , Aged , Annexin A2/metabolism , Brain/metabolism , Brain/pathology , Female , Gene Expression Regulation, Neoplastic , Glioma/metabolism , Glioma/pathology , Humans , Male , Middle Aged , Young Adult
13.
Se Pu ; 28(7): 654-63, 2010 Jul.
Article in Chinese | MEDLINE | ID: mdl-21046783

ABSTRACT

A gas chromatography-mass spectrometric (GC-MS) method has been established for the simultaneous determination of 103 pesticide residues in cabbages and apples using programmable temperature vaporizer-based large volume injection (PTV-LVI) and negative chemical ionization (NCI). It was found that much lower detection limits for the investigated pesticides can be obtained. Prior to GC-NCI/MS analysis, the optimized parameters of PTV-LVI were as follows: inlet temperature was set at 45 degrees C, split vent flow rate was 20 mL/min, evaporation time was 1 min and evaporation temperature was set at 60 degrees C. The volume of injection was 10 microL. Co-extractives were removed from the acetonitrile extracts using solid phase extraction with octadecyl (200 mg) and primary secondary amine (100 mg) sorbents. Matrix matched calibration solutions were used for all the analyses. To evaluate performance of the method, validation experiments were carried out in cabbages and apples at two spiking levels (5 and 10 microg/kg). The average recoveries ranged from 58.5% to 113.2%, and the relative standard deviations (RSDs, n = 6) were in the range of 3.3% - 14.5%. The limits of detection (S/N = 3) were less than 5 microg/kg for all the pesticides. The results show that this method is simple, rapid, sensitive and specific. It is appropriate for the simultaneous identification and quantification of the multi-residues in cabbages and apples.

14.
Anal Chim Acta ; 611(1): 56-61, 2008 Mar 17.
Article in English | MEDLINE | ID: mdl-18298967

ABSTRACT

Nanostructured titania-based solid-phase microextraction (SPME) fibers were fabricated through the in situ oxidation of titanium wires with H(2)O(2) (30%, w/w) at 80 degrees C for 24h. The obtained SPME fibers possess a approximately 1.2microm thick nanostructured coating consisting of approximately 100nm titania walls and 100-200nm pores. The use of these fibers for headspace SPME coupled with gas chromatography with electron capture detection (GC-ECD) resulted in improved analysis of dichlorodiphenyltrichloroethane (DDT) and its degradation products. The presented method to detect DDT and its degradation products has high sensitivity (0.20-0.98ngL(-1)), high precision (relative standard deviation R.S.D.=9.4-16%, n=5), a wide linear range (5-5000ngL(-1)), and good linearity (coefficient of estimation R(2)=0.991-0.998). As the nanostructured titania was in situ formed on the surface of a titanium wire, the coating was uniformly and strongly adhered on the titanium wire. Because of the inherent chemical stability of the titania coating and the mechanical durability of the titanium wire substrate, this new SPME fiber exhibited long life span (over 150 times).


Subject(s)
Nanostructures , Titanium/analysis , Chromatography, Gas , DDT/analysis , Microscopy, Electron, Scanning , Pesticides/analysis , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Surface Properties
15.
J Sep Sci ; 30(13): 2138-43, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17654617

ABSTRACT

The feasibility of single-walled carbon nanotubes (SWCNTs) as adsorbents for solid-phase microextraction was investigated by using organochlorine pesticides (OCPs) as model compounds. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method has a linear range of 2-800 ng/L for most analytes, with coefficients of correlation ranging from 0.9911 to 0.9996, LODs ranged from 0.19 to 3.77 ng/L (S/N = 3), and RSDs in the range of 3.5-13.9% (n = 5). Compared with the commercial PDMS fiber, the SWCNT fiber has better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied to determine trace OCPs in lake water and wastewater samples with external standard calibration. Results showed that OCP contamination was very low in these samples, and HCHs were detected in almost all water samples while DDT concentrations were almost under detection limits in these samples. Recoveries obtained at 20 ng/L spiking level were in the range of 88.4-111% for OCPs in lake water. For wastewater samples, however, the recoveries were satisfactory for HCHs (63.6-97.1%) but relatively low for DDTs (44.7-116%) due to the high content of organic matter in wastewater.


Subject(s)
Fresh Water/chemistry , Hydrocarbons, Chlorinated/chemistry , Nanotubes, Carbon/chemistry , Pesticides/chemistry , Solid Phase Microextraction , Adsorption , Animals , Humans , Materials Testing , Solid Phase Microextraction/instrumentation , Solid Phase Microextraction/methods , Surface Properties , Waste Disposal, Fluid
16.
J Pharm Biomed Anal ; 35(4): 679-87, 2004 Jun 29.
Article in English | MEDLINE | ID: mdl-15193712

ABSTRACT

Quantitative structure-activity relationship (QSAR) models of inhibiting action of some diarylimidazole derivatives on cylcooxygenase (COX) enzyme were constructed using modified particle swarm optimization (PSO) method. As a comparison to this method, the genetic algorithm (GA) was also tested. It has been demonstrated that the modified PSO is a useful tool for variable selection comparable to GA and even superior to GA. QSAR models are constructed separately for COX-2 inhibitory activity and selectivity of COX-2 inhibition over COX-1. The spatial descriptors play a key role in the compounds' activity and selectivity to COX-2, especially Jurs descriptors. Polar interactions are the principal binding strength between compounds and COX-2 enzyme. In addition, the aqueous desolvation free energy (FH2O) value of substituent will affect the COX-2 inhibitory activity, while the charge distribution can affect the selectivity to COX-2.


Subject(s)
Cyclooxygenase Inhibitors/chemistry , Linear Models , Quantitative Structure-Activity Relationship
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