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AIM: To investigate the distribution of refractive parameters and theirs correlation with spherical equivalent(SE)in preschool children aged 3 to 6 years, and evaluate the accuracy of each screening index in diagnosing refractive errors.METHODS: Cross-sectional study. A total of 791 preschool children, ranging from 3 to 6 years old, who consented to undergo mydriatic refraction were selected. Axial length(AL), corneal refractive power(K), and SE were measured after microcoria optometry and mydriatic optometry. Additionally, the corneal radius of curvature(CR)and the axial length/corneal radius of curvature(AL/CR)ratio were calculated.RESULTS: A total of 791 students participated in the study, out of which 400(50.6%)were male and 391(49.4%)were female. The mean values for AL, CR, AL/CR, and SE were 22.62±0.94mm, 7.81±0.29mm, 2.90±0.09, and +1.95±1.31D, respectively. AL, CR, and AL/CR increased with age. AL and CR were significantly higher in males than in females(all P<0.001), while there was no statistically significant difference between AL/CR and SE in males and females(P=0.82, 0.19). The correlation coefficients of SE and AL/CR, AL and CR were -0.86, -0.50 and 0.16, respectively. The results of multiple linear regression analysis indicate that for each unit increase in AL/CR, there was a corresponding shift of 10.91 towards myopia in SE. The sensitivity of AL/CR in screening for myopia was 94.44%, with a specificity of 90.46% and a Youden index of 0.84. For screening myopia under microcoria optometry, the sensitivity was 100%, with a specificity of 66.09% and a Youden index of 0.66. The area under the curve was 0.967 and 0.809 when the ROC curves were plotted using AL/CR and AL as indicators for screening myopia, respectively.CONCLUSION: For large group screening activities where mydriatic optometry is not feasible, AL/CR is better for evaluating refractive status and identifying children with myopia and hyperopia reserve that are lower than normal for their age, compared to AL and microcoria optometry.
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AIM: To investigate the effect of the intravitreal injection of vascular endothelial growth factor-A165(VEGF-A165)on the scleral remodeling of guinea pigs with form-deprivation myopia(FDM).METHODS: A total of 120 tricolor guinea pigs, aged three weeks, were randomly divided into 6 groups, with 20 in each group. The blank group did not undergo any intervention. In the FDM group, only the FDM model was established. In the phosphate buffer saline(PBS)group, 2.5 μL of PBS was injected into the vitreous cavity before establishing the FDM model. In the 1ng group, 5ng group, and 10ng group, VEGF-A165 was injected into the vitreous cavity at concentrations of 1, 5 and 10ng, respectively, before the establishment of the FDM model. The FDM model was established by covering the right eyes of guinea pigs with translucent balloons for 14d. The diopter and axial length of the right eyes were measured before and after covering. After 14d, the content of dopamine(DA)in retina was measured by high performance liquid chromatography. Additionally, the mRNA and protein expression levels of matrix metalloproteinase-2(MMP-2), tissue inhibitor of matrix metalloproteinase-2(TIMP-2), transforming growth factor(TGF)-β1, TGF-β2 and α-smooth muscle actin(α-SMA)in sclera were detected by reverse transcription polymerase chain reaction(RT-PCR)and Western blot.RESULTS: Before covering, there were no significant differences in the diopter and axial length of the right eyes of guinea pigs in all groups(P>0.05). After 14d of modeling, when compared with the blank group, FDM group showed an increase in the degree of myopia in the right eye, a prolongation of the axial length, a decrease in the content of DA in the retina, and an increase in the expression of MMP-2, TGF-β2 and α-SMA in the sclera. Conversely, the expression of TIMP-2 and TGF-β1 were decreased(P<0.01). However, in comparison to the FDM group, the degree of myopia in the 1ng, 5ng, and 10ng groups of guinea pigs decreased, the growth trend of axial length slowed, the content of DA in the retina increased, and the expression of MMP-2, TGF-β2 and α-SMA in the sclera decreased. Furthermore, the expression of TIMP-2 and TGF-β1 in the sclera increased(P<0.01). As the concentration of intravitreal injection of VEGF-A165 increased, the degree of myopia in the right eye of guinea pigs gradually increased, and the axial length gradually prolonged. The content of DA in the retina gradually decreased, the expression of MMP-2, TGF-β2, and α-SMA in the sclera gradually increased, while the expression of TIMP-2 and TGF-β1 decreased gradually.CONCLUSION: Intravitreal injection of VEGF-A165 can increase the content of DA in the retina of FDM guinea pigs, affect the expression of MMP-2, TIMP-2, TGF-β1, TGF-β2 and α-SMA in the sclera, and inhibit scleral remodeling of guinea pigs. Notably, the VEGF-A165 at the concentration of 1ng showed the most significant efficacy.
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Abstract@#Comprehensive sexuality education is an important part of quality education, primary and secondary schools are the most suitable places for sex education. This paper sorts out the current status of sexuality education for primary and secondary school students in developed countries after presenting the overall significance of school based sexuality education, and further points out the problems and urgency of sexuality education for primary and secondary school students in China. It also put forward the way to new directions for advocacy, including the comphrehensive sexuality education curriculum system, training of sexuality education teachers, the positive and active role of families, as well as social and community support for sexuality education in schools.
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Objective:To investigate the clinical features of Trousseau's syndrome with acute multiple cerebral infarction (AMCI) as the first manifestation. Methods:From January, 2012 to January, 2019, a retrospective study was conducted on 19 patients with AMCI diagnosed as the first manifestation of Trousseau's syndrome. The clinical data, imaging features, laboratory results, treatment, and prognosis data were collected and analyzed. Results:They were (71.05±10.59) years old, with ten males and nine females. MRI-diffusion weighted imaging (DWI) showed numerous small lesions with or without large area cerebral infarction in multiple vascular territories. Fifteen cases (78.95%) showed bilateral infarction, eleven cases (57.89%) showed multiple small lesions (< 20 mm) in multiple vascular territories, nine cases showed cerebral artery stenosis, in which seven cases (77.78%) of cerebral infarction lesions were not consistent with stenotic vessels. All patients had elevated levels of D-dimer with a median of 3.08 mg/L (0.79~7.00 mg/L). Cardiac troponin I (cTnI) increased in eight cases. CA125 increased in 17 cases. Among the 15 cases treated with antiplatelet therapy, five cases (33.3%) were combined with anticoagulation therapy. Nine cases (47.37%) developed early neurological function deterioration or recurrent cerebral infarction during hospitalization. After the follow-up, five cases died within 30 days, and six recurrent thrombotic events occurred within 90 days, including three events for cerebral infarction and three events for lower limb venous thrombosis, and finally 13 cases (68.42%) died within 90 days. Conclusion:AMCI can be the first manifestation of Trousseau's syndrome. The image features including bilateral small infarction or multiple lesions being not consistent with the stenotic vessels, combined with the elevated levels of D-dimer, cTnI and CA125, can be the clues to Trousseau's syndrome caused by hypercoagulability due to cancer. Timely screening for occult cancer and active anticancer therapy may be helpful to improve their outcome.
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OBJECTIVE: To investigate the prevalence and relevant influencing factors of gynecological diseases of grassroot level female medical staffs. METHODS: A total of 2 308 female medical workers from county, town and village in hengxian County of Guangxi Zhuang Autonomous Region were selected as study subjects by cluster sampling method. The basic information, occupational history, reproductive health and fertility of these subjects were investigated by Reproducetive Health Survey Questionnaine of Female Workers. RESULTS: The total prevalence of gynecological diseases in female medical staffs was 21.6%. Among them, the prevalence of genital tract infections was 15.6%, and gynecological tumors was 6.0%. The top three gynecologic diseases were vaginitis(9.2%), uterine fibroids(4.3%) and cervicitis(3.5%). Multivariate logistic regression analysis results indicated that the younger the patients, the higher the risk of reproductive tract infectious diseases(P<0.01), and the lower the risk of gynecological tumors(P<0.01). The risk of reproductive tract infectious diseases and gynecological tumors in married patients was higher than that in unmarried staffs(P<0.05). The higher the number of abortions, the higher the risk of reproductive tract infectious diseases and gynecological tumors(P<0.01). The risk of reproductive tract infectious diseases was higher and the risk of gynecological tumors was lower in female shift workers than that of non-shift workers(P<0.05). CONCLUSION: Vaginitis, uterine fibroids and cervicitis are the main gynecological diseases in grassroot level female medical staffs. The incidence of gynecological diseases is related to age, history of marriage, childbirth and abortion, and work-shifts.
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BACKGROUND@#Estradiol, as an important hormone in follicular development and endometrial receptivity, is closely related to clinical outcomes of fresh in vitro fertilization embryo transfer (IVF-ET) cycles. The aim of this retrospective study was to evaluate the association between elevated serum estradiol (E2) levels on the day of human chorionic gonadotrophin (hCG) administration and IVF-ET pregnancy and birth outcomes.@*METHODS@#A total of 1771 infertile patients with their first fresh IVF-ET cycles were analyzed retrospectively between January 2011 and January 2016 in Peking University First Hospital. Patients were categorized by serum E2 levels on the day of hCG administration into six groups: group 1 (serum E2 levels ≤ 1000 pg/mL, n = 205), group 2 (serum E2 levels 1001-2000 pg/mL, n = 457), group 3 (serum E2 levels 2001-3000 pg/mL, n = 425), group 4 (serum E2 levels 3001-4000 pg/mL, n = 310), group 5 (serum E2 levels 4001-5000 pg/mL, n = 237), and group 6 (serum E2 levels > 5000 pg/mL, n = 137). The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates of the groups were compared as the first objective of the study. For the 360 women with singleton births among all patients, the area under the corresponding receiver operating characteristic curve (ROC curve) was calculated to assess the predictive value of the E2 change for the probability of low birth weight (LBW) infants as the second objective.@*RESULTS@#The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates gradually increased from groups 1 to 5 but decreased in group 6. The parameters of group 1 were statistically worse than those of the other groups, from group 2 to group 6 (the number of retrieved oocytes, t = 13.096, t = 23.307, t = 23.086, t = 26.376, t = 19.636, P < 0.003; the number of retrieved MII oocytes, t = 10.856, t = 20.868, t = 21.874, t = 23.374, t = 19.092, P < 0.003; the implantation rate, χ = 12.179, χ = 22.239, χ = 23.993, χ = 23.344, χ = 16.758, P < 0.003; the clinical pregnancy rate, χ = 16.415, χ = 28.074, χ = 35.387, χ = 37.025, χ = 24.590, P < 0.003). ROC analysis revealed that when a serum peak E2 of 3148 pg/mL was used to predict LBW.@*CONCLUSIONS@#The results indicate that serum E2 levels have a concentration-dependent effect on clinical outcomes. The optimal range of the E2 level during a fresh IVF-ET cycle is 1000 to 3148 pg/mL.
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Background:@#Estradiol, as an important hormone in follicular development and endometrial receptivity, is closely related to clinical outcomes of fresh in vitro fertilization embryo transfer (IVF-ET) cycles. The aim of this retrospective study was to evaluate the association between elevated serum estradiol (E2) levels on the day of human chorionic gonadotrophin (hCG) administration and IVF-ET pregnancy and birth outcomes.@*Methods:@#A total of 1771 infertile patients with their first fresh IVF-ET cycles were analyzed retrospectively between January 2011 and January 2016 in Peking University First Hospital. Patients were categorized by serum E2 levels on the day of hCG administration into six groups: group 1 (serum E2 levels ≤ 1000 pg/mL, n = 205), group 2 (serum E2 levels 1001–2000 pg/mL, n = 457), group 3 (serum E2 levels 2001–3000 pg/mL, n = 425), group 4 (serum E2 levels 3001–4000 pg/mL, n = 310), group 5 (serum E2 levels 4001–5000 pg/mL, n = 237), and group 6 (serum E2 levels > 5000 pg/mL, n = 137). The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates of the groups were compared as the first objective of the study. For the 360 women with singleton births among all patients, the area under the corresponding receiver operating characteristic curve (ROC curve) was calculated to assess the predictive value of the E2 change for the probability of low birth weight (LBW) infants as the second objective.@*Results:@#The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates gradually increased from groups 1 to 5 but decreased in group 6. The parameters of group 1 were statistically worse than those of the other groups, from group 2 to group 6 (the number of retrieved oocytes, t = 13.096, t = 23.307, t = 23.086, t = 26.376, t = 19.636, P < 0.003; the number of retrieved MII oocytes, t = 10.856, t = 20.868, t = 21.874, t = 23.374, t = 19.092, P < 0.003; the implantation rate, χ2 = 12.179, χ2 = 22.239, χ2 = 23.993, χ2 = 23.344, χ2 = 16.758, P < 0.003; the clinical pregnancy rate, χ2 = 16.415, χ2 = 28.074, χ2 = 35.387, χ2 = 37.025, χ2 = 24.590, P < 0.003). ROC analysis revealed that when a serum peak E2 of 3148 pg/mL was used to predict LBW.@*Conclusions:@#The results indicate that serum E2 levels have a concentration-dependent effect on clinical outcomes. The optimal range of the E2 level during a fresh IVF-ET cycle is 1000 to 3148 pg/mL.
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Objective:To study on the differences of profile spectra among chemical components in Magnoliae Officinalis Cortex from different varieties and habitats,and to screen and identify the characteristic components affecting the quality difference of this herb. Method:The chromatogram data sets of Magnoliae Officinalis Cortex from different varieties and habitats were obtained by liquid chromatography-time-of-flight-mass spectrometry(LC-TOF-MS).Principal component analysis,partial least squares-discriminant analysis and cluster analysis were used to compare the differences in chemical profiles among Magnoliae Officinalis Cortex from different varieties and habitats,and adopted to screen out the characteristic chemical constituents that resulted in these differences and to perform mass spectrometry analysis and comparison. Result:Eleven characteristic peaks were identified by LC-TOF-MS chromatographic data and reported in the literature.The use of chemical profile could distinguish different habitats of Magnoliae Officinalis Cortex,but could not completely distinguish different varieties of this herb. Conclusion:LC-TOF-MS can easily and quickly study on the profile differences of chemical substances in Magnoliae Officinalis Cortex from different varieties and different habitats,the results of this study can provide a theoretical basis for the quality evaluation and pharmacodynamic material basis of this herb.
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AIM To investigate the effect and mechanism of methanolic extract of Eupatorium (MEOE) to model rats with chronic soft tissue injury.METHODS The model rats were established by mechanical injury and a subsequent two-week normal feeding for respective administration of high,medium and small dosage of MEOE once a day successively for 14 days.An array of indices,the level of superoxide dismutase (SOD),malondialdehyde (MDA),prostaglandin E2 (PGE2),nitric oxide (NO),interleukin-6 (IL-6) and histamine,the expression of tumor necrosis factor-alpha (TNF-α),nitric oxide (NO) and Collagen-Ⅰ/Ⅲ,and the activity of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were measured to analyze the effect of MEOE to model rats with chronic muscle injury.RESULTS MEOE resulted in apparent reduction of contents of MDA,PGE2 and NO,and the levels of TNF-α and IL-6 in muscular tissue (P < 0.05),significantly increased of the SOD in muscular tissue (P < 0.01),a remarkably inhibited expression of the tissue Collagen-Ⅰ/Ⅲ protein (P < 0.01),and significantly improved activity of tissue VEGF and bFGF (P < 0.01).CONCLUSION The certain therapeutic effects of MEOE to rats with chronic muscle injury may correlate with its influence to the levels of inflammatory factors inhibition,the oxidative stress relief,the overexpression of collagen-Ⅰ/Ⅲ inhibition,the VEGF and bFGF activity improvement,and the time spare from the repairing.
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Two Gram-negative, aerobic, non-motile, rod-shaped bacterial strains, FH13T and FH23, representing a novel group of Rhizobium isolated from root nodules of Phaseolus vulgaris in Mexico, were studied by a polyphasic analysis. Phylogeny of 16S rRNA gene sequences revealed them to be members of the genus Rhizobium related most closely to 'Rhizobium anhuiense' CCBAU 23252 (99.7 % similarity), Rhizobium leguminosarum USDA 2370T (98.6 %), and Rhizobium sophorae CCBAU 03386T and others ( ≤ 98.3 %). In sequence analyses of the housekeeping genes recA, glnII and atpD, both strains formed a subclade distinct from all defined species of the genus Rhizobium at sequence similarities of 82.3-94.0 %, demonstrating that they represented a novel genomic species in the genus Rhizobium. Mean levels of DNA-DNA relatedness between the reference strain FH13T and the type strains of related species varied between 13.0 ± 2.0 and 52.1 ± 1.2 %. The DNA G+C content of strain FH13T was 63.5âmol% (Tm). The major cellular fatty acids were 16 : 0, 17 : 0 anteiso, 18 : 0, summed feature 2 (12 : 0 aldehyde/unknown 10.928) and summed feature 8 (18 : 1ω7c). The fatty acid 17 : 1ω5c was unique for this strain. Some phenotypic features, such as failure to utilize adonitol, l-arabinose, d-fructose and d-fucose, and ability to utilize d-galacturonic acid and itaconic acid as carbon source, could also be used to distinguish strain FH13T from the type strains of related species. Based upon these results, a novel species, Rhizobium acidisoli sp. nov., is proposed, with FH13T ( = CCBAU 101094T = HAMBI 3626T = LMG 28672T) as the type strain.
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Phaseolus/microbiología , Filogenia , Rhizobium/clasificación , Nódulos de las Raíces de las Plantas/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , México , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , Rhizobium/genética , Rhizobium/aislamiento & purificación , Análisis de Secuencia de ADNRESUMEN
The reliability and validity of risk assessment scale (RAS) of pressure sore during 3S surgery were investigated. RAS of pressure sore was designed independently during 3S surgery. Five operating room nursing experts were selected to consult and detect face validity. Convenient and purposive sampling of 707 samples was conducted. Cronbach's alpha was used to measure content reliability and evaluate the internal consistence of RAS. The structural reliability was investigated by exploratory factor analysis method. The results showed that the content validity index was 0.92, and Cronbach's alpha of content reliability was 0.71. Structural validity, detected by Bartlett sphericity test, was 135.3 for 707 samples with the difference being statistically significant (P<0.01). KMO value was 0.729. The accumulative variance contribution ratio of common factor was 64.63%. The exploratory factor analysis showed the factor load of every clause was larger than 0.596. It was concluded that RAS of pressure sore for 3S surgery has better validity and reliability, and it could be used for evaluating and screening the high risk patients with pressure sores during surgery in order to efficiently reduce the occurrence of pressure sore during surgery. RAS of pressure sore for 3S surgery is worth to be popularized.
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Humanos , Periodo Intraoperatorio , Úlcera por Presión , Reproducibilidad de los Resultados , Medición de Riesgo , Encuestas y CuestionariosRESUMEN
The reliability and validity of risk assessment scale (RAS) of pressure sore during 3S surgery were investigated. RAS of pressure sore was designed independently during 3S surgery. Five operating room nursing experts were selected to consult and detect face validity. Convenient and purposive sampling of 707 samples was conducted. Cronbach's alpha was used to measure content reliability and evaluate the internal consistence of RAS. The structural reliability was investigated by exploratory factor analysis method. The results showed that the content validity index was 0.92, and Cronbach's alpha of content reliability was 0.71. Structural validity, detected by Bartlett sphericity test, was 135.3 for 707 samples with the difference being statistically significant (P<0.01). KMO value was 0.729. The accumulative variance contribution ratio of common factor was 64.63%. The exploratory factor analysis showed the factor load of every clause was larger than 0.596. It was concluded that RAS of pressure sore for 3S surgery has better validity and reliability, and it could be used for evaluating and screening the high risk patients with pressure sores during surgery in order to efficiently reduce the occurrence of pressure sore during surgery. RAS of pressure sore for 3S surgery is worth to be popularized.
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Objective ToanalyzetheepidemiccharacteristicsofepidemicencephalitisBinGuangxiZhuangminority autonomousregionduring2005-2012andtoevaluatethecontrolstrategies.Methods Descriptiveepidemiological methods were used to compare epidemic characteristics before and after conducting the national expanded program of immunization.Then all the strategies conducted by local department including seasonal vaccination enhancing,ordinary vaccination,emergencyvaccination,regularvaccinationandmonitorsystemestablishingwereevaluated.Results During 2005 -2012,a total of 1 135 cases were recorded with the annual average incidence of 0.29/100000 and this rate declined every year by 16.80%.Additionally,the incidence rate was seasonal.The peak day (July 1 st)of incidence and the peak period (June 2nd-July 29th)of epidemic were delayed after conducting the expanded program of immunization.The scope of epidemic-stricken area was narrowed down.However,the incidence was still high (1.11 ~1.79/100,000)in the groupofchildrenaged5-7years.Conclusion TheoutbreakandepidemicofepidemicencephalitisBwereterminated owing to the establishment of monitor system and immunity strategy.The epidemic circle was broken and the incidence rate dropped to its lowest level in history.
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Summarize the value of the change of different parts in treadmill exercise test (TET) ECG to coronary heart disease (CHD) diagnosis. Four hundred and forty-five cases have been included in this investigation, which stayed in our hospital from January of 2006 to March of 2011 and underwent TET and coronary arteriography (CAG). The change of different parts in TET ECG in these patients had been retrospective summarized to determine its diagnosis value to CHD. (1) In the 445 cases of TET testers, 200 cases showed positive in TET with 150 cases of positive CAG, and 50 cases of negative CAG; 245 cases showed negative in TET with 206 cases of negative CAG, and 39 cases of positive CAG. The diagnosis sensitivity of CHD was 79.36% (150/189), the specificity was 80.47% (206/256), positive prediction value was 75.00% (150/200), negative prediction value was 84.08% (206/245), and false-positive rate was 25.00% (50/200) with prediction accuracy of 80.00% (356/445). (2) In the 200 cases with positive TET: 51 cases were in the limb lead group; 73 cases were in the chest lead group; and 76 cases were in the limb lead + chest lead group. There were 150 cases showing positive in CAG: 22 cases were in the limb lead group; 58 cases were in the chest lead group; and 70 cases were in the limb lead + chest lead group. The positive diagnosis rate of ST change in the chest lead was obviously higher than that of simple limb lead group (P < 0.05). (3) People with healthy coronary artery will have decreased amplitude of R wave while patients with coronary stenosis have elevated amplitude of R wave. (4) As for the T wave, the positive CAG had no statistical significance between normal T wave group and TET positive group (P > 0.05); CAG results had statistical significance between normal T wave group and TET negative group (P < 0.05). (5) Positive CAG results had no statistical significance between U-wave inversion group and TET positive group (P > 0.05); positive CAG results has statistical significance when TET negative group compared with U-wave inversion group or TET positive group (P < 0.05). TET is a relatively idea invasive diagnosis method for coronary disease, which can be utilized to evaluate the stage of CHD when integrating with the change of TET ECG.
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Enfermedad Coronaria/diagnóstico , Prueba de Esfuerzo , Adulto , Anciano , Anciano de 80 o más Años , Presión Sanguínea , Angiografía Coronaria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
<p><b>OBJECTIVE</b>To introduce a simple, fast and universal measuring method used in measurement of the surface area of scalp flap over the cranial defect after decompressive craniectomy.</p><p><b>METHODS</b>The first step: CT images of the patient with craniocerebral trauma after decompressive craniectomy were obtained and imported into Mimics. The second step: based on the defined threshold, the 3D geometric models of brain and skull were reconstructed after the original Dicom format pictures three-dimensional processed by Mimics. The third step: based on the two builded 3D models, utilizing the segmentation and measurement tools of Mimics to conduct cutting, splitting and measuring operations for the 3D model of brain. The forth step: estimating the surface area of scalp flap over the removed bone flap by using mathematical computation methods.</p><p><b>RESULTS</b>The application of the introduced method estimated the surface area of scalp flap over the cranial defect of different people with different position of craniocerebral trauma.</p><p><b>CONCLUSIONS</b>This paper introduces a simple, fast and universal new measuring method. We can conveniently estimate the surface area of scalp flap by using the introduced method.</p>
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Humanos , Craniectomía Descompresiva , Métodos , Imagenología Tridimensional , Modelos Anatómicos , Cuero Cabelludo , Cirugía General , Colgajos Quirúrgicos , Tomografía Computarizada por Rayos XRESUMEN
<p><b>OBJECTIVE</b>In order to make certain the compaction pressure as well as pre-sintering temperature on the machinability of the zirconia ceramic.</p><p><b>METHODS</b>3 mol nano-size 3 mol yttria partially stabilized zirconia (3Y-TZP) powder were compacted at different isostatic pressure and sintered at different temperature. The cylindrical surface was traversed using a hard metal tool. Surface and edge quality were checked visually using light stereo microscopy.</p><p><b>RESULTS</b>Pre-sintering temperature had the obviously influence on the machinability of 3Y-TZP. The cutting surface was smooth, and the integrality of edge was better when the pre-sintering temperature was chosen between 800 degrees C to 900 degrees C. Compaction pressure showed only a weak influence on machinability of 3Y-TZP blanks, but the higher compaction pressure result in the poor surface quality.</p><p><b>CONCLUSION</b>The best machinability of pre-sintered zirconia body was found for 800-900 degrees C pre-sintering temperature, and 200-300 MPa compaction pressure.</p>
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Cerámica , Temperatura , Itrio , CirconioRESUMEN
We have developed a regiospecific and highly stereoselective strategy for constructing the five-/six-membered monocyclic and bicyclic nitrogen heterocycle skeletons using PhSe group transfer radical cyclization of alpha-phenylseleno amido esters promoted by a Lewis acid (e.g., Yb(OTf)(3)) under UV irradiation. We obtained 5-/6-exo-trig mode cyclization products for the N-allyl/homoallyl substrates, whereas the enamide substrate gave 5-endo-trig ring closure.
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Lactamas/síntesis química , Mesilatos/química , Compuestos Organometálicos/química , Compuestos de Organoselenio/química , Ciclización , Radicales Libres/síntesis química , Radicales Libres/química , Lactamas/química , Estructura Molecular , Estereoisomerismo , Rayos UltravioletaRESUMEN
We have developed a strategy for constructing nitrogen heterocycles by photoinduced PhSe group transfer radical cyclization. trans-Alpha,beta-disubstituted gamma-butyrolactams (2-pyrrolidinones) were prepared in good yields (38-73%) with high regioselectivity and stereoselectivity from N-alkenyl alpha-PhSe beta-keto amides. Reaction outcomes were modulated by the steric effect of the substituents on the nitrogen atom of the cyclization precursors and the stereoelectronic effect of the substrates. Diphenyldiselenide, as an additive, was found to promote ring closure. The advantage of this strategy in natural product synthesis is demonstrated by a formal synthesis of (+/-)-isocynometrine.
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4-Butirolactona/síntesis química , Alcaloides/síntesis química , Imidazoles/síntesis química , Compuestos de Organoselenio/química , 4-Butirolactona/análogos & derivados , 4-Butirolactona/química , Alcaloides/química , Ciclización , Radicales Libres/química , Imidazoles/química , Estructura Molecular , Fotoquímica , EstereoisomerismoRESUMEN
<p><b>BACKGROUND</b>Many cytokines have been found to increase the insulin resistance during pregnancy complicated by glucose metabolism disorder. This study aimed to investigate which comes first, the changes of some cytokines or the abnormal glucose metabolism.</p><p><b>METHODS</b>This nested case-control study was undertaken from January 2004 to March 2005. Twenty-two women with gestational diabetes mellitus (GDM), 10 with gestational impaired glucose tolerance (GIGT), and 20 healthy pregnant women were chosen from the women who had visited the antenatal clinics and had blood samples prospectively taken and kept during their visit. The levels of tumor necrosis factor-alpha (TNF-alpha), leptin and adiponectin were determined. One-way ANOVA analysis and bivariate correlation analysis were used to assess the laboratory results and their relationship with body mass index (BMI).</p><p><b>RESULTS</b>Women with GDM have the highest values of TNF-alpha and leptin and the lowest value of adiponectin compared with those with GIGT and the healthy controls (P < 0.01) at 14-20 weeks of gestation. This was also found when these women progressed to 24-32 weeks. The significantly increased levels of TNF-alpha and leptin and the decreased level of adiponectin were found at the different periods of gestation within the same group. Positive correlation was shown between the levels of TNF-alpha and leptin at the two periods of gestation with the BMI at 14-20 weeks, while adiponectin was negatively correlated (P < 0.05).</p><p><b>CONCLUSIONS</b>The concentrations of TNF-alpha, leptin and adiponectin may change before the appearance of the abnormal glucose level during pregnancy. Further studies are required to verify the mechanism of this alteration and whether the three cytokines can be predictors for GDM at an early stage of pregnancy.</p>
Asunto(s)
Femenino , Humanos , Embarazo , Adiponectina , Sangre , Estudios de Casos y Controles , Diabetes Gestacional , Sangre , Intolerancia a la Glucosa , Leptina , Sangre , Estudios Prospectivos , Factor de Necrosis Tumoral alfa , SangreRESUMEN
<p><b>OBJECTIVE</b>To study the influence of two-step sintering method on the sintering property, mechanical properties and microstructure of zirconia ceramic.</p><p><b>RESULTS</b>The nano-size zirconia powder were compacted and divided into two groups, one group for one-step sintering method, another group for two-step sintering method. All samples sintered at different temperature. The relative density, three-bend strength, HV hardness, fracture toughness and microstructure of sintered block were investigated.</p><p><b>RESULTS</b>Two-step sintering method influenced the sintering property and mechanical properties of zirconia ceramic. The maximal relative density was 98.49% at 900 degrees C/1,450 degrees C sintering temperature. There were significant difference of mechanical properties between one-step sintering and two-step sintering, the three-bend strength and fracture toughness declined, hardness increased at two-step sintering. The three-bend strength, HV hardness and fracture toughness reached to maximum value as 1,059.08 MPa +/- 75.24 MPa, 1,377.00 MPa +/- 16.37 MPa and 5.92 MPa x m1/2 +/- 0.37 MPa x m1/2 at 900 degrees C/1,450 degrees C sintering temperature respectively. Microscopy revealed the relationship between the porosity and shapes of grains was correlated to strength of the zirconia ceramics.</p><p><b>CONCLUSION</b>Despite of the two-step sintering method influences the properties of zirconia, it also is a promising esthetic all-ceramic dental material.</p>