Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 154
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Stat Methods Med Res ; : 962280219882047, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31640479

RESUMO

We propose a non-monotone transformation to biomarkers in order to improve the diagnostic and screening accuracy. The proposed quadratic transformation only involves modeling the distribution means and variances of the biomarkers and is therefore easy to implement in practice. Mathematical justification was rigorously established to support the validity of the proposed transformation. We conducted extensive simulation studies to assess the performance of the proposed method and compared the new method with the traditional methods. Case studies on real biomedical and epigenetics data were provided to illustrate the proposed transformation. In particular, the proposed method improved the AUC values for a large number of markers in a DNA methylation study and consequently led to the identification of greater number of important biomarkers and biologically meaningful genetic pathways.

2.
Zhongguo Gu Shang ; 32(7): 677-682, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31382729

RESUMO

At present, artificial vertebral implants have proven to be effective in the treatment of spinal tumors, infections, fractures and other diseases. However, the fusion artificial vertebral body can cause adjacent intervertebral joint degeneration and loss of original physiological curvature and activity. The movable artificial vertebral body can, to some extent, restore the normal physiological movement and reduce biomechanical changes of the spine, reducing the occurrence of complication. The design of movable artificial vertebral body is to equip movable device when the basis of reliable stability is obtained. According to its principle it can be divided into ball socket joint or elastic deformation. However the overall design of movable artificial vertebral body needs further improvement. Traditional mechanical processing methods are difficult to process complex prostheses and the agreement rate between traditional produced prostheses and lesions was low. While the emerging 3D printing technology can achieve individualized improvement of prosthesis, its slow rate and high cost need to be improved. The materials of movable artificial vertebral body includes metal, ceramics, biomaterials, high polymer materials and so on. Titanium alloy is the main material in metal materials, which is widely used, but its modulus of elasticity is still far from that of human bone and it lacks ideal bone fusion. Ceramic materials are rich in variety but fragile and poor in wear resistance. Biomaterials include autogenous bone, allogeneic bone, etc., with limited source and complicated operation. There are many kinds of polymer and biodegradable materials which obtain excellent and ideal properties. But their properties and applications need to be further studied. The movable artificial vertebral body still needs to be promoted and developed. The clinical experimental data is still insufficient, and long-term curative effect needs to be further observed and studied. This paper reviews the development, advantages, design, processing and materials of movable artificial vertebral bodies and provides useful reference for optimization design, processing and clinical application of movable artificial vertebral bodies.


Assuntos
Coluna Vertebral , Materiais Biocompatíveis , Fenômenos Biomecânicos , Humanos , Próteses e Implantes , Neoplasias da Coluna Vertebral , Titânio
3.
World Neurosurg ; 129: e87-e96, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31150848

RESUMO

BACKGROUND: For multilevel cervical fusion, anterior corpectomy and fusion (ACCF) induces more implant-related complications than anterior diskectomy and fusion (ACDF), which implies that the biomechanical stability of ACCF may be insufficient. The aim of this study was to assess whether the optimization of the cage profiles could improve the biomechanical performance of multilevel ACCF. METHODS: Three finite element models were constructed and compared, including 3-level ACDF, 2-level ACCF using a conventional cage for reconstruction, and 2-level ACCF using a new cage for reconstruction. The ends of the new cage possessed additional end rings and emulated the end plate geometries. The ranges of motion (ROMs) of the surgical segments and the stress peaks in the end plate, fixation system, and screw-bone interface were compared. RESULTS: Compared with preoperative status, ACDF and ACCF reduced the segmental ROMs by 96.1%-98.2%. The end plate stress peaks were the highest in ACCF using the conventional cage (10.1-18.6 MPa), followed by ACCF using the new cage (7.7-14.3 MPa) and ACDF (5.3-9.1 MPa). ACDF induced the highest stress peaks in the fixation system and screw-bone interface (32.5-39.3 MPa and 12.1-12.7 MPa, respectively), followed by ACCF using the conventional cage (20.4-31.7 MPa and 10.3-13.6 MPa, respectively) and ACCF using the new cage (18.6-25.7 MPa and 9.7-12.6 MPa, respectively). CONCLUSIONS: The application of the new cage decreased the risks of cage subsidence and instrument-related complications in multilevel ACCF. Under the condition where cage subsidence was prevented, ACCF was superior to ACDF in terms of construct stability and avoiding instrument-related complications.

4.
PLoS Med ; 16(6): e1002831, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31199800

RESUMO

BACKGROUND: Socioeconomic disparities in infant mortality have persisted for decades in high-income countries and may have become stronger in some populations. Therefore, new understandings of the mechanisms that underlie socioeconomic differences in infant deaths are essential for creating and implementing health initiatives to reduce these deaths. We aimed to explore whether and the extent to which preterm birth (PTB) and small for gestational age (SGA) at birth mediate the association between maternal education and infant mortality. METHODS AND FINDINGS: We developed a population-based cohort study to include all 1,994,618 live singletons born in Denmark in 1981-2015. Infants were followed from birth until death, emigration, or the day before the first birthday, whichever came first. Maternal education at childbirth was categorized as low, medium, or high. An inverse probability weighting of marginal structural models was used to estimate the controlled direct effect (CDE) of maternal education on offspring infant mortality, further split into neonatal (0-27 days) and postneonatal (28-364 days) deaths, and portion eliminated (PE) by eliminating mediation by PTB and SGA. The proportion eliminated by eliminating mediation by PTB and SGA was reported if the mortality rate ratios (MRRs) of CDE and PE were in the same direction. The MRRs between maternal education and infant mortality were 1.63 (95% CI 1.48-1.80, P < 0.001) and 1.19 (95% CI 1.08-1.31, P < 0.001) for low and medium versus high education, respectively. The estimated proportions of these total associations eliminated by reducing PTB and SGA together were 55% (MRRPE = 1.27, 95% CI 1.15-1.40, P < 0.001) for low and 60% (MRRPE = 1.11, 95% CI 1.01-1.22, P = 0.037) for medium versus high education. The proportions eliminated by eliminating PTB and SGA separately were, respectively, 46% and 11% for low education (versus high education) and 48% and 13% for medium education (versus high education). PTB and SGA together contributed more to the association of maternal educational disparities with neonatal mortality (proportion eliminated: 75%-81%) than with postneonatal mortality (proportion eliminated: 21%-23%). Limitations of the study include the untestable assumption of no unmeasured confounders for the causal mediation analysis, and the limited generalizability of the findings to other countries with varying disparities in access and quality of perinatal healthcare. CONCLUSIONS: PTB and SGA may play substantial roles in the relationship between low maternal education and infant mortality, especially for neonatal mortality. The mediating role of PTB appeared to be much stronger than that of SGA. Public health strategies aimed at reducing neonatal mortality in high-income countries may need to address socially related prenatal risk factors of PTB and impaired fetal growth. The substantial association of maternal education with postneonatal mortality not accounted for by PTB or SGA could reflect unaddressed educational disparities in infant care or other factors.

5.
Int J Epidemiol ; 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31209487

RESUMO

BACKGROUND: Previous simulation studies of the case-control study design using incidence density sampling, which required individual matching for time, showed biased estimates of association from conditional logistic regression (CLR) analysis; however, the reason for this is unknown. Separately, in the analysis of case-control studies using the exclusive sampling design, it has been shown that unconditional logistic regression (ULR) with adjustment for an individually matched binary factor can give unbiased estimates. The validity of this analytic approach in incidence density sampling needs evaluation. METHODS: In extensive simulations using incidence density sampling, we evaluated various analytic methods: CLR with and without a bias-reduction method, ULR with adjustment for time in quintiles (and residual time within quintiles) and ULR with adjustment for matched sets and bias reduction. We re-analysed a case-control study of Haemophilus influenzae type B vaccine using these methods. RESULTS: We found that the bias in the CLR analysis from previous studies was due to sparse data bias. It can be controlled by the bias-reduction method for CLR or by increasing the number of cases and/or controls. ULR with adjustment for time in quintiles usually gave results highly comparable to CLR, despite breaking the matches. Further adjustment for residual time trends was needed in the case of time-varying effects. ULR with adjustment for matched sets tended to perform poorly despite bias reduction. CONCLUSIONS: Studies using incidence density sampling may be analysed by either ULR with adjustment for time or CLR, possibly with bias reduction.

6.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(4): 409-414, 2019 Apr 30.
Artigo em Chinês | MEDLINE | ID: mdl-31068283

RESUMO

OBJECTIVE: To assess the geometrical matching of a new anatomical adaptive titanium mesh cage (AA-TMC) with the endplate and its effect on cervical segmental alignment reconstruction in single- and two-level anterior cervical corpectomy and fusion (ACCF) and compare the compressive load at the endplate between the AA-TMC and the conventional titanium mesh cage (TMC). METHODS: Twelve cervical cadaveric specimens were used to perform single- and two-level ACCF. The interbody angle (IBA), interbody height (IBH) and the interval between the AA-TMC and the endplate were evaluated by comparison of the pre- and postoperative X-ray images. The maximum load at the endplate was compared between the AA-TMC and TMC based on American Society for Testing and Materials (ASTM) F2267 standard. RESULTS: No significant differences were found between the preoperative and postoperative IBA and IBH in either single-level ACCF (11.62°±2.67° vs 12.13°±0.69° and 23.90±2.18 mm vs 24.23±1.13 mm, respectively; P > 0.05) or two-level ACCF (15.63°±5.06° vs 16.16°±1.05°and 42.93±3.51 mm vs 43.04±1.70 mm, respectively; P > 0.05). The mean interval between the AA-TMC and the endplate was 0.37 ± 0.3 mm. Compared to the conventional TMC, the use of AA-TMC significantly increased the maximum load at the endplate in both single-level ACCF (719.7±5.5 N vs 875.8±5.2 N, P < 0.05) and two-level ACCF (634.3±5.9 N vs 873±6.1 N, P < 0.05). CONCLUSIONS: The use of AA-TMC in single-level and two-level ACCF can significantly increase the maximum load at the endplate to lower the possibility of implant subsidence and allows effective reconstruction of the cervical alignment.


Assuntos
Vértebras Cervicais , Fusão Vertebral , Fenômenos Biomecânicos , Humanos , Próteses e Implantes , Telas Cirúrgicas , Titânio , Resultado do Tratamento
7.
Stat Med ; 38(17): 3256-3271, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31066095

RESUMO

In the clinical trial community, it is usually not easy to find a treatment that benefits all patients since the reaction to treatment may differ substantially across different patient subgroups. The heterogeneity of treatment effect plays an essential role in personalized medicine. To facilitate the development of tailored therapies and improve the treatment efficacy, it is important to identify subgroups that exhibit different treatment effects. We consider a very general framework for subgroup identification via the homogeneity pursuit methods usually employed in econometric time series analysis. The change point detection algorithm in our procedure is most suitable for analyzing dense longitudinal or spatial data which are quite common for biomedical studies these days. We demonstrate that our proposed method is fast and accurate through extensive numerical studies. In particular, our method is illustrated by analyzing a diffusion tensor imaging data set.

8.
Phytomedicine ; 59: 152921, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31055231

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with poor prognosis. Various chemotherapeutics are used in treatment of HCC, but most of them have significant toxicity to patients. Thus, it is urgently needed to develop new therapeutic strategies to achieve high specificity and tolerable adverse effects. As a natural polyphenol, ellagic acid (EA) demonstrates inhibitory effects in cancers. PURPOSE: The goal of the present study to investigate the anticancer activity of EA with a focus on its stimulating effects on doxorubicin hydrochloride (DOX) and cisplatin (DDP) in HCC treatment. METHODS: HepG2, SMMC-7721 and HL-7702 cells were treated with EA, DOX, DDP or their combinations. Cell viability and apoptosis were examined to evaluate the cytotoxicity of these treatments. Western blot analysis and immunofluorescent assays were used to determine expression of genes related to the mitochondrial apoptosis pathway. To assess the anticancer activities and systemic toxicity of EA, DOX and EA+DOX treatments, a xenograft mouse model with inoculated HepG2 cells was employed, followed by immunohistochemical and histopathological evaluation. RESULTS: EA could both markedly potentiate anticancer activities of DOX and DDP to HCC HepG2 and SMMC-7721 cells, and reduce their cytotoxicity to normal liver HL-7702 cells. EA and its combination with DOX or DDP induced cell apoptosis through a pathway mediated by mitochondrial cytochrome c release. In nude mice, EA combination with a relatively low dosage of DOX effectively inhibited tumor growth without causing cardiotoxicity observed in mice treated by a high dosage of DOX. CONCLUSION: We discovered that EA synergistically potentiated DOX and DDP in suppressing HCC with significantly reduced side effects and this may represent a novel strategy in HCC therapies with both high anticancer efficiencies and low systemic toxicity in patients.


Assuntos
Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Sobrevivência Celular/efeitos dos fármacos , Ácido Elágico/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/patologia , Cardiotoxicidade , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Cisplatino/uso terapêutico , Doxorrubicina/administração & dosagem , Doxorrubicina/uso terapêutico , Humanos , Camundongos , Camundongos Nus , Neoplasias Experimentais , Fitoterapia
9.
Aquat Toxicol ; 212: 138-145, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31125791

RESUMO

Multiple antibiotics are simultaneously detected in aquatic environment, so it is extremely important to study the combined effects of their mixtures. In this study, we investigated the toxic effects of erythromycin (ERY) and enrofloxacin (ENR), added individually or in combination, on Chlorella vulgaris and explored the toxic mechanisms. Results showed that the 96 h-EC50 values of ERY, ENR and ERY-ENR mixture to C. vulgaris were 85.7, 124.5 and 39.9 µg L-1 respectively, and combined toxicity assessment found that joint effect of the two antibiotics was synergism, which was proven by the chlorophyll content in algae. Antioxidant defense system and photosynthesis were involved in toxic mechanisms and the results revealed that both the activities of antioxidant enzymes, and the malondialdehyde (MDA) and glutathione (GSH) contents increased in antibiotic treatments. In addition, the increase was more significant in joint exposure treatment, which implied that the antioxidant defense system was synergistically affected. RT-PCR showed that ERY and ENR upregulated the transcript abundance of psaB, psbC and chlB at low concentrations and the transcription abundance was synergistically increased in combined treatment. Therefore, the risk of the toxicity of antibiotics to aquatic organisms in real environment both at organismal and molecular level increases as a result of their combined presence.


Assuntos
Antioxidantes , Chlorella vulgaris/efeitos dos fármacos , Enrofloxacina/toxicidade , Eritromicina/toxicidade , Transcrição Genética/efeitos dos fármacos , Antibacterianos/farmacologia , Chlorella vulgaris/enzimologia , Chlorella vulgaris/genética , Clorofila/metabolismo , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Glutationa/metabolismo , Malondialdeído , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade
10.
Stat Med ; 38(14): 2605-2631, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-30887552

RESUMO

Thresholding variable plays a crucial role in subgroup identification for personalized medicine. Most existing partitioning methods split the sample based on one predictor variable. In this paper, we consider setting the splitting rule from a combination of multivariate predictors, such as the latent factors, principle components, and weighted sum of predictors. Such a subgrouping method may lead to more meaningful partitioning of the population than using a single variable. In addition, our method is based on a change point regression model and thus yields straight forward model-based prediction results. After choosing a particular thresholding variable form, we apply a two-stage multiple change point detection method to determine the subgroups and estimate the regression parameters. We show that our approach can produce two or more subgroups from the multiple change points and identify the true grouping with high probability. In addition, our estimation results enjoy oracle properties. We design a simulation study to compare performances of our proposed and existing methods and apply them to analyze data sets from a Scleroderma trial and a breast cancer study.

11.
Stat Med ; 38(13): 2477-2503, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30701585

RESUMO

Deep learning neural network models such as multilayer perceptron (MLP) and convolutional neural network (CNN) are novel and attractive artificial intelligence computing tools. However, evaluation of the performance of these methods is not readily available for practitioners yet. We provide a tutorial for evaluating classification accuracy for various state-of-the-art learning approaches, including familiar shallow and deep learning methods. For qualitative response variables with more than two categories, many traditional accuracy measures such as sensitivity, specificity, and area under the receiver operating characteristic curve are not applicable and we have to consider their extensions properly. In this paper, a few important statistical concepts for multicategory classification accuracy are reviewed and their utilities for various learning algorithms are demonstrated with real medical examples. We offer problem-based R code to illustrate how to perform these statistical computations step by step. We expect that such analysis tools will become more familiar to practitioners and receive broader applications in biostatistics.

12.
J Alzheimers Dis ; 68(1): 197-203, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30775990

RESUMO

We examined the cross-sectional association between mushroom intake and mild cognitive impairment (MCI) using data from 663 participants aged 60 and above from the Diet and Healthy Aging (DaHA) study in Singapore. Compared with participants who consumed mushrooms less than once per week, participants who consumed mushrooms >2 portions per week had reduced odds of having MCI (odds ratio = 0.43, 95% CI 0.23-0.78, p = 0.006) and this association was independent of age, gender, education, cigarette smoking, alcohol consumption, hypertension, diabetes, heart disease, stroke, physical activities, and social activities. Our cross-sectional data support the potential role of mushrooms and their bioactive compounds in delaying neurodegeneration.

13.
Environ Res ; 171: 145-152, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30665116

RESUMO

Eighteen sediments and four biota species were collected from mangrove wetlands of the Jiulong River Estuary (JRE) in South China to investigate the distribution of dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), dechlorane plus (DP) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Concentrations of ΣDDTs, ΣPCBs, ΣPBDEs, DBDPE, DP, and BTBPE in mangrove sediments ranged from 21 to 84, 0.52-2.5, 9.0-66, 5.1-32, 0.05-0.14, and 0.03-0.25 ng/g dry weight, respectively. Levels of ΣDDTs, ΣPCBs, ΣPBDEs, DBDPE and DP in mangrove biota ranged from 950 to 30000, 56-400, 8.0-35, nd-20 and 0.44-3.1 ng/g lipid weight, respectively. DDTs were the predominant halogenated organic pollutants (HOPs) in mangrove sediments from the JRE, while PBDEs were the major HOPs in mangrove sediments from the Pearl River Estuary (PRE), suggesting that sediments in JRE and PRE had different sources of HOPs. The dominance of DDTs was found in both mangrove sediments and biota from the JRE, indicating that HOPs in JRE environment mainly come from agricultural sources. The biota-sediment accumulation factors for DDTs and PCBs were significantly higher than those of PBDEs, DBDPE and DP, suggesting high bioavailability of DDTs and PCBs in mangrove biota. Trophic magnification factors for DDTs, PCBs, PBDEs, and DP were 10.5, 3.00, 2.66 and 1.23, respectively, indicating their potential of biomagnification in mangrove food webs.

14.
J Cell Physiol ; 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30515785

RESUMO

Notch proteins are highly conserved cell surface receptors which play essential roles in cellular differentiation, proliferation, and apoptotic events at all stages of development. Recently, NOTCH1 mutations have been extensively observed in oral squamous cell carcinoma (OSCC) and are hinted to be Notch1-inactivating mutations. However, little is known about the biological effect of these reported mutations in OSCC. To mimic the inactivation of Notch1 due to inappropriate mutations and to determine the potential mechanisms, we utilized wild-type Notch1 vectors (Notch1WT ) or mutant Notch1 vectors (Notch1V1754L ) to transfect into OSCC cell lines. Membrane-tethered Notch1 induced by mutation was analyzed by immunofluorescence staining. γ-Secretase inhibitor PF-03084014 was utilized to determine the phenotype in the absence of endogenous Notch1 activation. Here we demonstrated that membrane-tethered Notch1 inactivated the canonical Notch1 signaling and oncogenic phenotypes were identified by promoting cell proliferation and invasion and by inducing epithelial-to-mesenchymal transition in cells. The γ-secretase inhibitor PF-03084014 also showed distinct oncogenic property after treatment. Importantly, both membrane-tethered Notch1 and PF-03084014 inhibitor activated the epidermal growth factor receptor (EGFR)-phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling pathway, which has been confirmed as an overwhelming modulator in OSCC. This was the first time that we clearly simulated the mutated Notch1 activities and determined the oncogenic phenotypes of membrane-tethered Notch1. Compared with wild-type Notch1, membrane-tethered Notch1 was strongly associated with activated EGFR-PI3K-AKT signaling pathway.

15.
Stat Methods Med Res ; : 962280218812211, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30453845

RESUMO

It is often necessary to differentiate subjects from multiple categories using medical tests. We may then adopt statistical measures to characterize the performance of these tests. The three-way ROC analysis has been proposed to evaluate the diagnostic accuracy of medical tests with three categories, reflecting the correct classification probabilities across all possible decision thresholds. The geometry of the ROC surface is carefully studied, leading to numerical summary measures such as the volume under the surface. This paper generalizes the global volume under the surface of three-way ROC analysis to the weighted volume under the surface (WVUS) by introducing a weight function emphasizing particular regions of correct classification probabilities. This generalization practically allows researchers to calculate the diagnostic accuracy for a medical or clinical biomarker while satisfactorily high probabilities of correct classification for one or two classes are conditionally ensured. We provide the asymptotic properties of the proposed nonparametric and parametric estimators of WVUS, which could easily lend support to statistical inferences. Some simulations have been conducted to assess the proposed estimators and also to demonstrate the necessity of WVUS. A real data analysis about liver cancer illustrates our methodology.

16.
Epidemiol Infect ; : 1-9, 2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30360767

RESUMO

Dengue fever (DF) has been a growing public-health concern in China since its emergence in Guangdong Province in 1978. Of all the regions that have experienced dengue outbreaks in mainland China, the city of Guangzhou is the most affected. This study aims to investigate the potential risk factors for dengue virus (DENV) transmission in Guangzhou, China, from 2006 to 2014. The impact of risk factors on DENV transmission was qualified by the q-values calculated using a novel spatial-temporal method, the GeoDetector model. Both climatic and socioeconomic factors were considered. The impacts on DF incidence of each single factor and the interaction of two factors were analysed. The results show that the number of days with rainfall of the month before last has the highest determinant power, with a q-value of 0.898 (P < 0.01); the q-values of the other factors related to temperature and precipitation were around 0.38-0.50. Integrating a Pearson correlation analysis, nonlinear associations were found between the DF incidence in Guangzhou and the climatic factors considered. The coupled impact of the different variables considered was enhanced compared with their individual effects. In addition, an increased number of tourists in the city were associated with a high incidence of DF. This study demonstrates that the number of rain days in a month has great influence on the DF incidence of the month after next; the temperature and precipitation have nonlinear impacts on the DF incidence in Guangzhou; both the domestic and overseas tourists coming to the city increase the risk of DENV transmission. These findings are useful in the risk assessment of DENV transmission, to predict DF outbreaks and to implement preventive DF reduction strategies.

17.
Front Aging Neurosci ; 10: 195, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30042673

RESUMO

Introduction: This study is a parallel-arm randomized controlled trial evaluating choral singing's efficacy and underlying mechanisms in preventing cognitive decline in at-risk older participants. Methods: Three-hundred and sixty community-dwelling, non-demented older participants are recruited for a 2-year intervention. Inclusion criteria are self-reported cognitive complaints, early cognitive impairment based on neuropsychological test scores or multiple risk factors of dementia. Participants are randomized to either weekly choral singing sessions or general health education. The primary outcome is cognitive performance, measured by a composite cognitive test score (CCTS). Secondary outcomes include depression, anxiety and neuropsychiatric symptoms; perceived stress; sleep quality and severity of dementia symptoms. Underlying mechanisms are examined using blood- and urine-based biomarkers and neuroimaging. Results: Screening began in July 2016. The first group of participants (n = 93) have been recruited. Intervention and control treatments are ongoing and will end in December 2019. Discussion: An evidence-based singing intervention for dementia prevention holds potential for healthcare savings and societal welfare. Trial Registration: NCT02919748, IRB Approval Number: NUS 2508.

18.
Comput Biol Med ; 99: 182-190, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29936284

RESUMO

Endoscopy is becoming one of the widely-used technologies to screen the gastric diseases, and it heavily relies on the experiences of the clinical endoscopists. The location, shape, and size are the typical patterns for the endoscopists to make the diagnosis decisions. The contrasting texture patterns also suggest the potential lesions. This study designed a novel rotation-tolerant image feature, TriZ, and demonstrated the effectiveness on both the rotation invariance and the lesion detection of three gastric lesion types, i.e., gastric polyp, gastric ulcer, and gastritis. TriZ achieved 87.0% in the four-class classification problem of the three gastric lesion types and the healthy controls, averaged over the twenty random runs of 10-fold cross-validations. Due to that biomedical imaging technologies may capture the lesion sites from different angles, the symmetric image feature extraction algorithm TriZ may facilitate the biomedical image based disease diagnosis modeling. Compared with the 378,434 features of the HOG algorithm, TriZ achieved a better accuracy using only 126 image features.

19.
Biometrics ; 2018 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-29775198

RESUMO

Forecasting and predictive inference are fundamental data analysis tasks. Most studies employ parametric approaches making strong assumptions about the data generating process. On the other hand, while nonparametric models are applied, it is sometimes found in situations involving low signal to noise ratios or large numbers of covariates that their performance is unsatisfactory. We propose a new varying-coefficient semiparametric model averaging prediction (VC-SMAP) approach to analyze large data sets with abundant covariates. Performance of the procedure is investigated with numerical examples. Even though model averaging has been extensively investigated in the literature, very few authors have considered averaging a set of semiparametric models. Our proposed model averaging approach provides more flexibility than parametric methods, while being more stable and easily implemented than fully multivariate nonparametric varying-coefficient models. We supply numerical evidence to justify the effectiveness of our methodology.

20.
Plast Reconstr Surg ; 141(5): 1272-1281, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29697628

RESUMO

BACKGROUND: Venous complications are the primary reason for flap loss in massive defect reconstructions; therefore, the quality and reliability of microvascular anastomoses are significant. The aim of this systematic review was to evaluate venous anastomotic time, the venous complication rate, and the flap failure rate with the mechanical anastomotic coupling device versus the hand-sewn technique in venous anastomoses of microvascular free flap operations. METHODS: Chinese and English databases were searched for eligible articles published between their inception and July of 2017. The pooled relative risk was calculated for dichotomous variables, and the weighted mean difference was calculated for continuous data. Whether to use the fixed effects or random effects model depended on the heterogeneity evaluation among the studies. RESULTS: Twelve studies were selected, including 3788 flaps (mechanical anastomotic coupling device, n = 1667; hand-sewn, n = 2121). Using the mechanical anastomotic coupling device significantly decreased venous anastomotic time (weighted mean difference, -13.50; 95 percent CI, -17.09 to -9.91; p < 0.01) and the incidence of venous complications (relative risk, 0.40; 95 percent CI, 0.25 to 0.65; p < 0.01). There was a significant difference in terms of flap failure between the groups (relative risk, 0.56; 95 percent CI, 0.32 to 0.97; p = 0.04); thus, flap survival improved with the assistance of the mechanical anastomotic coupling device. No publication bias was detected in those analyses. CONCLUSION: This meta-analysis suggests that the mechanical anastomotic coupling device contributes to reduced operative time, decreased probability of surgical reexploration, and mitigation of flap loss.


Assuntos
Anastomose Cirúrgica/efeitos adversos , Retalhos de Tecido Biológico/efeitos adversos , Microcirurgia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Procedimentos Cirúrgicos Reconstrutivos/efeitos adversos , Anastomose Cirúrgica/instrumentação , Anastomose Cirúrgica/métodos , Retalhos de Tecido Biológico/irrigação sanguínea , Humanos , Incidência , Microcirurgia/instrumentação , Microcirurgia/métodos , Complicações Pós-Operatórias/etiologia , Procedimentos Cirúrgicos Reconstrutivos/métodos , Técnicas de Sutura/efeitos adversos , Técnicas de Sutura/instrumentação , Veias/cirurgia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA