1.Mechanical And Surface Properties Of Initial And Working Aesthetic Orthodontic Archwires
Tang YC ; Peh XL ; Zakaria N N ; Radzi Z
Annals of Dentistry 2016;23(1):17-28
The study aimed to compare mechanical properties and surface characteristics of initial and workingaesthetic archwires with their conventional counterparts. High Aesthetic Sentalloy (full rhodium coatingnickel-titanium; Dentsply GAC) represented the initial aesthetic archwires; and FLI TRU-CHROME(labial PTFE-coated stainless steel; RMO) as the working aesthetic archwires; together with theirconventional counterparts were analysed. A three point bending test was conducted using a universaltesting machine (AGS-X SERIES, Shimadzu, Japan) to determine the load-deflection characteristics ofarchwires. Surface hardness was evaluated by Vickers microhardness test (HMV-FA, Shimadzu, Japan).A 3D Optical Surface Texture Analyzer (ALICONA, InfiniteFocus Real3D, Belgium) and a Field EmissionScanning Electron Microscope (FESEM, FEI Quanta 250, USA) were used for surface evaluation.Results showed that load-deflection characteristics of High Aesthetic Sentalloy archwires did not differfrom its control, whereas FLI TRU-CHROME archwires exhibited higher loading and unloading forcesthan its counterpart. No statistically significant difference in surface hardness was found between FLITRU-CHROME and its control archwires. The coating surfaces of both aesthetic archwires were rougherthan the non-coated conventional archwires, with similar roughness between non-coated surface of FLITRU-CHROME archwires and its counterpart. FLI TRU-CHROME archwires showed a distinct coatingthickness but coating layer is undefined in High Aesthetic Sentalloy archwires. In conclusion, the aestheticrhodium coated nickel titanium archwire has similar mechanical properties as control nickel titaniumarchwire without being adversely affected by the addition of the coating layer. The aesthetic coated PTFEstainless steel archwire has higher load response which could be an advantage as rigid wire in workingstage of orthodontic treatment. Based on their performance, their use could be recommended in caseswhere aesthetic aspect is crucial and where the friction aspect is not critical as their surface roughnessvalues increased.
2.College of Radiology, Academy of Medicine of Malaysia position on whole body screening CT scans in healthy asymptomatic individuals (2008)
ELM Ho ; BJJ Abdullah ; AAL Tang ; AJ Nordin ; AR Nair ; GCC Lim ; H Samad-Cheung ; KH Ng ; S Ponnusamy ; SF Abbas ; Bux SI ; S Arasaratnam ; YF Abdul Aziz ; S Venugopal ; Z Musa ; Z Abdul Manaf
Biomedical Imaging and Intervention Journal 2008;4(4):1-5
To date, the College of Radiology (CoR) does not see any clear benefit in performing whole body screening
computed tomography (CT) examinations in healthy asymptomatic individuals. There are radiation risk issues in CT and principles of screening should be adhered to. There may be a role for targeted cardiac screening CT that derives calcium score, especially for asymptomatic medium-risk individuals and CT colonography when used as part of a strategic programme for colorectal cancer screening in those 50 years and older. However, population based screening CT examinations may become appropriate when evidence emerges regarding a clear benefit for the patient outweighing the associated radiation risks.
3.Application of Bernoulli Process Model fitting the effect of intervention measures on sexual transmission among HIV sero-discordant couples.
Chinese Journal of Epidemiology 2018;39(6):755-759
Objectives: To undersand the outcomes of major intervention measures on sexual transmission among HIV sero-discordant couples. Methods: Bernoulli Process Model was applied to model the major influencing factors of HIV transmission among HIV sero-discordant couples. The major influencing factors appeared as consistent condom use, antiretroviral therapy, frequency of sexual behavior. These parameters were from the HIV sero-discordant couples in 30 counties in 4 provinces (Guangxi Zhuang Autonomous Region, Yunnan Province, Xinjiang Uygur Autonomous Region and Henan provinces) from January 1, 2011 to December 31, 2012. According to the main factors, modeling-intervention strategies and measures on reduction HIV transmission among serodiscordant couples were formed. Results: Data from the present proportion of consistent condom use (85%) modeling and the coverage of antiretroviral treatment (60%) showed that, the proportion of cumulative seroconversion among the spouses was 1.76%. Results from the sensitivity analysis on modeling the consistent condom use and the antiretroviral treatment showed that, when the coverage of antiretroviral treatment was as 90% and the proportion of consistent condom use increased from 50% to 90%, with 80.7% of the risk of spouse seroconversion could be reduced. Or, when the proportion of consistent condom use was as 90% and the coverage of antiretroviral treatment increased from 50% to 90%, with 64.5% of the risk of spouse seroconversion could be reduced. Conclusions: With measures as consistent condom use plus provision of timely antiretroviral therapy to HIV positive index spouses, the risk of sexual transmission among sero-discordant couples could be greatly reduced.
Anti-Retroviral Agents/therapeutic use*
;
China/epidemiology*
;
Condoms
;
Female
;
HIV Infections/virology*
;
HIV Seronegativity
;
HIV Seropositivity/epidemiology*
;
Humans
;
Male
;
Safe Sex
;
Sexual Behavior/statistics & numerical data*
;
Sexual Partners
;
Spouses
4.Acceptability of HIV testing using oral quick self-testing kit in men who have sex with men.
X F WANG ; Z Y WU ; Z Z TANG ; Q X NONG ; Y Q LI
Chinese Journal of Epidemiology 2018;39(7):937-942
Objective: To evaluate the acceptability of oral quick HIV self-testing in men who have sex with men (MSM). Methods: From April 2013 to April 2014, MSM in Beijing and Nanning of China were recruited for an observational study including baseline survey and follow-up, including questionnaire survey, oral HIV self-testing and clinic-based HIV confirmation testing. The sensitivity and specificity of oral quick self-testing were evaluated through comparing the results of oral quick testing with blood testing. The acceptability and associated factors were evaluated by logistic model. Results: A total of 510 MSM were recruited at baseline survey and 279 accepted follow-up. The sensitivity of the oral self-test was 86.00% (43/50) and specificity was 98.23% (445/453) at baseline survey. At baseline survey, 78.63% (401/510) of the MSM showed willingness to use oral quick HIV self-testing. The associated factors included unprotected anal intercourse with a regular male partner in the past 6 months (aOR=0.30, 95%CI: 0.10-1.00) and preference of oral quick HIV self-testing (aOR=7.32, 95%CI: 1.61- 33.31). At baseline survey, 34.51% (176/510) of the MSM reported that oral quick HIV self-testing was the preferred testing method rather than blood testing, which was associated with their birth places-urban area. Conclusion: The acceptability of oral quick HIV self- testing in MSM in the two cities was high.
Adolescent
;
Adult
;
China/epidemiology*
;
Cross-Sectional Studies
;
HIV Infections/prevention & control*
;
Homosexuality, Male/statistics & numerical data*
;
Humans
;
Male
;
Patient Acceptance of Health Care
;
Patient Participation
;
Sexual and Gender Minorities
5. Metabolomics for characterization of gender differences in patients infected with dengue virus
Nurul SHAHFIZA ; Tang T. HOCK ; Abdel-Hamid Z. ABDEL-HAMID ; Hasnah OSMAN ; Khozirah SHAARI ; Abdel-Hamid Z. ABDEL-HAMID
Asian Pacific Journal of Tropical Medicine 2015;8(6):451-456
Objective: To determine the metabolic response associate with dengue infection based on human gender metabolic differences by means of 1H NMR-spectrometry. Methods: The mid-stream urine collected from both male and female patients diagnosed with dengue fever at Penang General Hospital and fourty-three healthy individuals were analyzed with 1H NMR spectroscopy, followed by chemometric multivariate analysis. NMR signals which highlighted in the OPLS-DA S-plot were further selected and identified using Human Metabolome Database, Chenomx Profiler. Results: The results pointed out that NMR urine profiling was able to capture human gender metabolic differences that are important for the distinction of classes of individuals of similar physiological conditions; infected with dengue. Distinct differences between dengue infected patients versus healthy individuals and subtle differences in male versus female infected with dengue were found to be related to the metabolism of amino acid and tricarboxylic acid intermediates cycle. Conclusions: The 1H NMR metabolomic investigation combined with appropriate algorithms and pattern recognition procedures, gave an evidence for the existence of distinct metabolic differentiation of individuals, according to their gender, modulates with the infection risk.
6.Protein interactions in the murine cytomegalovirus capsid revealed by cryoEM.
Wong H HUI ; Qiyi TANG ; Hongrong LIU ; Ivo ATANASOV ; Fenyong LIU ; Hua ZHU ; Z Hong ZHOU
Protein & Cell 2013;4(11):833-845
Cytomegalovirus (CMV) is distinct among members of the Herpesviridae family for having the largest dsDNA genome (230 kb). Packaging of large dsDNA genome is known to give rise to a highly pressurized viral capsid, but molecular interactions conducive to the formation of CMV capsid resistant to pressurization have not been described. Here, we report a cryo electron microscopy (cryoEM) structure of the murine cytomegalovirus (MCMV) capsid at a 9.1 Å resolution and describe the molecular interactions among the ∼3000 protein molecules in the MCMV capsid at the secondary structure level. Secondary structural elements are resolved to provide landmarks for correlating with results from sequence-based prediction and for structure-based homology modeling. The major capsid protein (MCP) upper domain (MCPud) contains α-helices and β-sheets conserved with those in MCPud of herpes simplex virus type 1 (HSV-1), with the largest differences identified as a "saddle loop" region, located at the tip of MCPud and involved in interaction with the smallest capsid protein (SCP). Interactions among the bacteriophage HK97-like floor domain of MCP, the middle domain of MCP, the hook and clamp domains of the triplex proteins (hoop and clamp domains of TRI-1 and clamp domain of TRI-2) contribute to the formation of a mature capsid. These results offer a framework for understanding how cytomegalovirus uses various secondary structural elements of its capsid proteins to build a robust capsid for packaging its large dsDNA genome inside and for attaching unique functional tegument proteins outside.
Amino Acid Sequence
;
Capsid Proteins
;
chemistry
;
metabolism
;
ultrastructure
;
Cryoelectron Microscopy
;
Models, Molecular
;
Molecular Sequence Data
;
Muromegalovirus
;
chemistry
;
ultrastructure
;
Protein Binding
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Protein Multimerization
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Protein Structure, Quaternary
;
Protein Structure, Tertiary
7.Genetic characteristics of hemagglutinin and neuraminidase of avian influenza A (H7N9) virus in Guizhou province, 2014-2017.
Y H WAN ; L ZHUANG ; Q N ZHENG ; L J REN ; L FU ; W J JIANG ; G P TANG ; D Z ZHANG ; S J LI
Chinese Journal of Epidemiology 2018;39(11):1465-1471
Objective: To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province. Methods: RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017. Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package. Results: Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8%-99.2% and 99.2% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2%-99.3% and 97.6%-98.8% similarities with vaccine strain A/Hunan/02650/2016, respectively. Other 6 stains detected in 2017 shared 99.1%-99.4% and 98.9%-99.3% similarities with strain A/Guangdong/17SF003/2016, respectively. Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch, but they were derived from different small branch. PEVPKRKRTAR↓GLF was found in 6 of 24 strains cleavage site sequences of HA protein, indicating the characteristic of highly pathogenic avian influenza virus. Mutations A134V, G186V and Q226L at the receptor binding sites were found in the HA. All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein, and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/18980/2017. In addition, potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains. Conclusions: HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017. The mutations of key sites might enhance the virulence of the virus, human beings are more susceptible to it. Hence, the risk of infection is increasing.
Animals
;
Base Sequence
;
Birds
;
China/epidemiology*
;
Genome, Viral
;
Hemagglutinin Glycoproteins, Influenza Virus/immunology*
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Hemagglutinins/genetics*
;
Humans
;
Influenza A Virus, H7N9 Subtype/isolation & purification*
;
Influenza in Birds
;
Influenza, Human/virology*
;
Neuraminidase/genetics*
;
Phylogeny
;
RNA, Viral/genetics*
;
Sequence Analysis, DNA
9.Experimental study on the molluscicidal activity of surfactin against Oncomelania hupensis.
Chinese Journal of Schistosomiasis Control 2023;35(4):394-397
OBJECTIVE:
To evaluate the molluscicidal activity of surfactin against Oncomelania hupensis, so as to provide the experimental basis for use of Bacillus for killing O. hupensis.
METHODS:
O. hupensis snails were collected from schistosomiasisendemic foci of Wuhu City on September 2022, and Schistosoma japonicum-infected snails were removed. Then, 60 snails were immersed in surfactin at concentrations of 2, 1, 0.5, 0.25, 0.125 mg/mL and 0.062 5 mg/mL for 24, 48, 72 hours at 26 °C, while ultrapure water-treated snails served as controls. The median lethal concentration (LC50) of surfactin against O. hupensis snails was estimated. O. hupensis snails were immersed in surfactin at a concentration of 24 h LC50 and ultrapure water, and then stained with propidium iodide (PI). The PI uptake in haemocyte was observed in O. hupensis snails using fluorescence microscopy.
RESULTS:
The mortality of O. hupensis was 5.0% following immersion in surfactin at a concentration of 0.062 5 mg/mL for 24 h, and the mortality was 100.0% following immersion in surfactin at a concentration of 2 mg/mL for 72 h, while no snail mortality was observed in the control group. There were significant differences in the mortality of O. hupensis in each surfactin treatment groups at 24 (χ2 = 180.150, P < 0.05), 48 h (χ2 = 176.786, P < 0.05) and 72 h (χ2 = 216.487, P < 0.05), respectively. The average mortality rates of O. hupensis were 38.9% (140/360), 62.2% (224/360) and 83.3% (300/360) 24, 48 h and 72 h post-immersion in surfactin, respectively (χ2 = 150.264, P < 0.05), and the 24, 48 h and 72 h LC50 values of surfactin were 0.591, 0.191 mg/mL and 0.054 mg/mL against O. hupensis snails. Fluorescence microscopy showed more numbers of haemocytes with PI uptake in 0.5 mg/mL surfactintreated O. hupensis snails than in ultrapure water-treated snails for 24 h, and there was a significant difference in the proportion of PI uptake in haemocytes between surfactin-and ultrapure water-treated snails (χ2 = 6.690, P < 0.05).
CONCLUSIONS
Surfactin is active against O. hupensis snails, which may be associated with the alteration in the integrity of haemocyte membrane.
Animals
;
Molluscacides/pharmacology*
;
Snails
;
Schistosoma japonicum
;
Lethal Dose 50
;
Water
10.Effect of baseline CD(4)(+) T cell count on drop-out of antiretroviral therapy in HIV infected persons in Guangxi Zhuang Autonomous Region, 2008-2015.
X H LIU ; Q Y ZHU ; J M SU ; Q MENG ; X J ZHOU ; Z Y SHEN ; Z Z TANG ; W M YANG ; Y H RUAN ; Y M SHAO
Chinese Journal of Epidemiology 2018;39(9):1216-1221
Objective: To investigate the effect of baseline CD(4)(+) T cell count (CD(4)) on drop-out of antiretroviral therapy (ART) in HIV infected persons. Methods: Retrospective cohort was conducted in this study. HIV infected persons aged≥18 years and receiving free ART for the first time in Guangxi Zhuang Autonomous Region (Guangxi) from 2008 to 2015 were selected from the antiretroviral treatment database of National Comprehensive HIV/AIDS Information System, with follow-up conducted till May 30, 2016. Cause-specific Cox proportional hazard models were used to evaluate effect of different CD(4) on the drop-out of ART in the HIV infected persons. Results: A total of 58 502 eligible study participants were included in this retrospective cohort study. The average drop-out ratio was 4.8/100 person-years. After controlling the following baseline covariates: age, sex, marital status, route of HIV infection, WHO clinical stage before ART, initial/current ART regiment, ART regiment adjustment, and year of initiating ART for potential confounding, the adjusted HR of drop-out for HIV infected persons with 200- cells/μl, 351-cells/μl and ≥500 cells/μl were 1.110 (95%CI: 1.053-1.171, P<0.001), 1.391 (95%CI: 1.278-1.514, P<0.001) and 1.695 (95%CI: 1.497-1.918, P<0.001), respectively, in risk for drop-out compared with those with baseline CD(4)<200 cells/μl. Among the HIV infected persons, 56.0% (1 601/2 861) of drug withdrawal was due to poor compliance with medication. Conclusions: With the increase of baseline CD(4) when initiating ART, the risk for the drop-out in HIV infected persons increased significantly. To further reduce the drop-out of ART, it is important to take CD(4) into account in initiating ART and to strengthen the health education on treatment compliancy and training for healthcare providers.
Adolescent
;
Anti-Retroviral Agents/administration & dosage*
;
CD4 Lymphocyte Count
;
China/epidemiology*
;
HIV
;
HIV Infections/virology*
;
Humans
;
Incidence
;
Medication Adherence
;
Retrospective Studies
;
T-Lymphocytes