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https://www.readbyqxmd.com/read/28222485/dose-response-modeling-in-mental-health-using-stein-like-estimators-with-instrumental-variables
#1
Cedric E Ginestet, Richard Emsley, Sabine Landau
A mental health trial is analyzed using a dose-response model, in which the number of sessions attended by the patients is deemed indicative of the dose of psychotherapeutic treatment. Here, the parameter of interest is the difference in causal treatment effects between the subpopulations that take part in different numbers of therapy sessions. For this data set, interactions between random treatment allocation and prognostic baseline variables provide the requisite instrumental variables. While the corresponding two-stage least squares (TSLS) estimator tends to have smaller bias than the ordinary least squares (OLS) estimator; the TSLS suffers from larger variance...
February 21, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28222109/ppd-induced-monocyte-mitochondrial-damage-is-associated-with-a-protective-effect-to-develop-tuberculosis-in-bcg-vaccinated-individuals-a-cohort-study
#2
Diana Marín, Nancy Marín, Helena Del Corral, Lucelly López, María Elena Ramirez-Agudelo, Carlos A Rojas, María P Arbeláez, Luis F García, Mauricio Rojas
INTRODUCTION: The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and resistance to mycobacterial replication, but it remains unknown whether or not they help predict the risk of developing TB. OBJECTIVE: To describe the factors associated with the induction of monocyte mitochondrial and membrane damage in response to PPD as well as determine if this type of damage might predict the susceptibility of developing active tuberculosis in a cohort of household contacts (HHCs) from Medellin, Colombia from 2005 to 2008...
2017: PloS One
https://www.readbyqxmd.com/read/28221983/biogenic-amines-and-predictive-models-of-quality-of-rainbow-trout-oncorhynchus-mykiss-fillets-during-storage
#3
Qingzheng Li, Jian Lv, Longteng Zhang, Zehong Dong, Ligeng Feng, Yongkang Luo
To estimate biogenic amines and changes in quality of rainbow trout ( Oncorhynchus mykiss ) fillets at different temperatures, we determined the sensory attributes, total volatile basic nitrogen (TVB-N), total viable counts (TVC), and biogenic amines (BAs) of samples that were untreated (CK) or dry cured with 1.8% salt (T). There was no significant difference between CK and T samples in terms of TVB-N, TVC, and BAs. TVB-N and TVC increased significantly (P < 0.05) with storage time at 3, 9, and 15°C. Putrescine (PUT) and cadaverine (CAD) increased significantly (P < 0...
February 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/28220302/sex-estimation-using-computed-tomography-of-the-mandible
#4
Tanya Sella Tunis, Rachel Sarig, Haim Cohen, Bahaa Medlej, Nathan Peled, Hila May
Sex estimation of skeletal parts is of great value even in the DNA era. When computed tomography (CT) facilities were introduced to forensic institutes, new possibilities for sex estimation emerged. The aim of this study was to develop a CT-based method for sex estimation using the mandible. Twenty-five CT-based measurements of the mandible were developed and carried out on 3D reconstructions (volume rendering) and cross sections of the lower jaw of 438 adult individuals (214 males and 224 females). Intraobserver and interobserver variances of the measurements were examined using intraclass correlation coefficient (ICC) analysis...
February 20, 2017: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/28219593/betel-nut-chewing-is-associated-with-reduced-tacrolimus-concentration-in-taiwanese-liver-transplant-recipients
#5
W-Y Chen, C-Y Lee, P-Y Lin, C-E Hsieh, C-J Ko, K-H Lin, C-C Lin, Y-Z Ming, Y-L Chen
PURPOSE: Studies have shown that arecoline, the major alkaloid component of betel nuts, alters the activity of enzymes in the cytochrome P450 (CYP-450) family. Tacrolimus, an immunosuppressant that protects against organ rejection in transplant recipients, not only is mainly metabolized by CYP3A enzymes but also has a narrow therapeutic range. We aimed to investigate whether dose-adjusted blood trough levels of tacrolimus differed over time between betel nut-chewing and non-betel nut-chewing liver transplant recipients...
March 2017: Transplantation Proceedings
https://www.readbyqxmd.com/read/28218481/an-analysis-of-sibling-correlations-in-health-using-latent-variable-models
#6
Timothy J Halliday, Bhashkar Mazumder
We investigate sibling correlations in youth health status using the Panel Study of Income Dynamics. We do so by estimating the covariance structure of a system of equations in latent variables using methods that have hitherto not been used in the literature on intergenerational transmissions of health. Across a battery of outcomes, we find that between 50 and 60% of health status can be attributed to shared familial or neighborhood characteristics. Taking the principal component across all outcomes, we obtain a sibling correlation of about 53%...
February 20, 2017: Health Economics
https://www.readbyqxmd.com/read/28218219/reduced-macular-vascular-density-in-myopic-eyes
#7
Hua Fan, Hao-Yu Chen, Hong-Jie Ma, Zheng Chang, Hai-Quan Yin, Danny Siu-Chun Ng, Carol Y Cheung, Shan Hu, Xiang Xiang, Shi-Bo Tang, Shuang-Nong Li
BACKGROUND: Morphological changes of the vasculature system in patients with myopia have been observed by Doppler ultrasound and fundus fluorescein angiography (FFA); however, these studies have limitations. Doppler ultrasound provides low-resolution images which are mainly obtained from visualized large vessels, and FFA is an invasive examination. Optic coherence tomography (OCT) angiography is a noninvasive, high-resolution measurement for vascular density. The purpose of this study was to investigate the change of vascular density in myopic eyes using OCT angiography...
2017: Chinese Medical Journal
https://www.readbyqxmd.com/read/28217249/cockcroft-gault-revisited-new-de-liver-ance-on-recommendations-for-use-in-cirrhosis
#8
REVIEW
Gianni B Scappaticci, Randolph E Regal
The Cockcroft-Gault (CG) equation has become perhaps the most popular practical approach for estimating renal function among health care professionals. Despite its widespread use, clinicians often overlook not only the limitations of the original serum creatinine (SCr) based equation, but also may not appreciate the validity of the many variations used to compensate for these limitations. For cirrhotic patients in particular, the underlying pathophysiology of the disease contributes to a falsely low SCr, thereby overestimating renal function with use of the CG equation in this population...
January 28, 2017: World Journal of Hepatology
https://www.readbyqxmd.com/read/28217244/estimating-causal-effects-with-ancestral-graph-markov-models
#9
Daniel Malinsky, Peter Spirtes
We present an algorithm for estimating bounds on causal effects from observational data which combines graphical model search with simple linear regression. We assume that the underlying system can be represented by a linear structural equation model with no feedback, and we allow for the possibility of latent variables. Under assumptions standard in the causal search literature, we use conditional independence constraints to search for an equivalence class of ancestral graphs. Then, for each model in the equivalence class, we perform the appropriate regression (using causal structure information to determine which covariates to include in the regression) to estimate a set of possible causal effects...
August 2016: JMLR Workshop and Conference Proceedings
https://www.readbyqxmd.com/read/28216557/a-methodology-to-monitor-airborne-pm10-dust-particles-using-a-small-unmanned-aerial-vehicle
#10
Miguel Alvarado, Felipe Gonzalez, Peter Erskine, David Cliff, Darlene Heuff
Throughout the process of coal extraction from surface mines, gases and particles are emitted in the form of fugitive emissions by activities such as hauling, blasting and transportation. As these emissions are diffuse in nature, estimations based upon emission factors and dispersion/advection equations need to be measured directly from the atmosphere. This paper expands upon previous research undertaken to develop a relative methodology to monitor PM10 dust particles produced by mining activities making use of small unmanned aerial vehicles (UAVs)...
February 14, 2017: Sensors
https://www.readbyqxmd.com/read/28216312/bone-marrow-lesions-on-magnetic-resonance-imaging-in-hand-osteoarthritis-are-associated-with-pain-and-interact-with-synovitis
#11
R Liu, W Damman, M Reijnierse, J L Bloem, F R Rosendaal, M Kloppenburg
OBJECTIVE: To determine the association between bone marrow lesions (BMLs) and (teno)synovitis as assessed on magnetic resonance (MR) imaging in patients with pain in hand osteoarthritis (OA). METHODS: In 105 consecutive primary hand OA patients (83% women, mean age 59 years), who were diagnosed by rheumatologists and included in the HOSTAS (Hand OSTeoArthritis in Secondary care) cohort, contrast-enhanced MR imaging of right distal and proximal interphalangeal joints were obtained...
February 12, 2017: Osteoarthritis and Cartilage
https://www.readbyqxmd.com/read/28215648/estimation-of-the-minimum-permeability-coefficient-in-rats-for-perfusion-limited-tissue-distribution-in-whole-body-physiologically-based-pharmacokinetics
#12
Yoo-Seong Jeong, Chang-Soon Yim, Heon-Min Ryu, Chi-Kyoung Noh, Yoo-Kyung Song, Suk-Jae Chung
The objective of the current study was to determine the minimum permeability coefficient, P, needed for perfusion-limited distribution in PBPK. Two expanded kinetic models, containing both permeability and perfusion terms for the rate of tissue distribution, were considered: The resulting equations could be simplified to perfusion-limited distribution depending on tissue permeability. Integration plot analyses were carried out with theophylline in 11 typical tissues to determine their apparent distributional clearances and the model-dependent permeabilities of the tissues...
February 12, 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28215584/earlier-age-at-menarche-in-girls-with-rapid-early-life-growth-cohort-and-within-sibling-analyses
#13
Julie D Flom, Barbara A Cohn, Parisa Tehranifar, Lauren C Houghton, Ying Wei, Angeline Protacio, Piera Cirillo, Karin B Michels, Mary Beth Terry
PURPOSE: The purpose of the article was to examine the association of early life growth with age at menarche. METHODS: Using data from a prospective birth cohort (n = 1134 women, 290 sibling sets), we assessed the association between postnatal growth at 4 months, 1 year, and 4 years and age at menarche, using generalized estimating equations and generalized linear random effects models. RESULTS: Overall, 18% of the cohort experienced early menarche (<12 years)...
January 19, 2017: Annals of Epidemiology
https://www.readbyqxmd.com/read/28215045/a-generalized-partially-linear-mean-covariance-regression-model-for-longitudinal-proportional-data-with-applications-to-the-analysis-of-quality-of-life-data-from-cancer-clinical-trials
#14
Xueying Zheng, Guoyou Qin, Dongsheng Tu
Motivated by the analysis of quality of life data from a clinical trial on early breast cancer, we propose in this paper a generalized partially linear mean-covariance regression model for longitudinal proportional data, which are bounded in a closed interval. Cholesky decomposition of the covariance matrix for within-subject responses and generalized estimation equations are used to estimate unknown parameters and the nonlinear function in the model. Simulation studies are performed to evaluate the performance of the proposed estimation procedures...
February 19, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28214619/transition-from-non-fickian-to-fickian-longitudinal-transport-through-3-d-rough-fractures-scale-in-sensitivity-and-roughness-dependence
#15
Lichun Wang, M Bayani Cardenas
Understanding transport in rough fractures from non-Fickian to Fickian regimes and the prediction of non-Fickian transport is critical for the development of new transport theories and many practical applications. Through computational experiments that fall within the macrodispersion regime, we first simulated and analyzed solute transport through synthetic rough fractures with stationary geometrical properties (i.e., fracture roughness σb/〈b〉 and correlation length λ, where b refers to aperture with its standard deviation σb and arithmetic mean 〈b〉) across increasing fracture longitudinal transport domain length L, with L/λ ranging from 2...
February 4, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28214123/a-tool-for-cost-effectiveness-analysis-of-field-scale-sediment-bound-phosphorus-mitigation-measures-and-application-to-analysis-of-spatial-and-temporal-targeting-in-the-lunan-water-catchment-scotland
#16
Andy Vinten, James Sample, Adekunle Ibiyemi, Yakubu Abdul-Salam, Marc Stutter
The cost-effectiveness of six edge-of-field measures for mitigating diffuse pollution from sediment bound phosphorus (P) runoff from temperate arable farmland is analysed at catchment/field scales. These measures were: buffer strips, permanent grassland in the lowest 7% of arable fields, dry detention bunds, wetlands, and temporary barriers such as sediment fences. Baseline field P export was estimated using export coefficients (low risk crops) or a modified Universal Soil Loss Equation (high risk crops). The impact of measures was estimated using simple equations...
February 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28213013/time-course-of-germination-initiation-of-mycelium-proliferation-and-probability-of-visible-growth-and-detectable-afb1-production-of-an-isolate-of-aspergillus-flavus-on-pistachio-extract-agar
#17
Laila Aldars-García, Vicente Sanchis, Antonio J Ramos, Sonia Marín
The aim of this work was to assess the temporal relationship among quantified germination, mycelial growth and aflatoxin B1 (AFB1) production from colonies coming from single spores, in order to find the best way to predict as accurately as possible the presence of AFB1 at the early stages of contamination. Germination, mycelial growth, probability of growth and probability of AFB1 production of an isolate of Aspergillus flavus were determined at 25 °C and two water activities (0.85 and 0.87) on 3% Pistachio Extract Agar (PEA)...
June 2017: Food Microbiology
https://www.readbyqxmd.com/read/28212398/modelling-the-risk-of-taenia-solium-exposure-from-pork-produced-in-western-kenya
#18
Lian F Thomas, William A de Glanville, Elizabeth A J Cook, Barend M De C Bronsvoort, Ian Handel, Claire N Wamae, Samuel Kariuki, Eric M Fèvre
The tapeworm Taenia solium is the parasite responsible for neurocysticercosis, a neglected tropical disease of public health importance, thought to cause approximately 1/3 of epilepsy cases across endemic regions. The consumption of undercooked infected pork perpetuates the parasite's life-cycle through the establishment of adult tapeworm infections in the community. Reducing the risk associated with pork consumption in the developing world is therefore a public health priority. The aim of this study was to estimate the risk of any one pork meal in western Kenya containing a potentially infective T...
February 17, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28211963/a-parametric-model-of-the-brain-vascular-system-for-estimation-of-the-arterial-input-function-aif-at-the-tissue-level
#19
Siamak P Nejad-Davarani, Hassan Bagher-Ebadian, James R Ewing, Douglas C Noll, Tom Mikkelsen, Michael Chopp, Quan Jiang
In this paper, we introduce a novel model of the brain vascular system, which is developed based on laws of fluid dynamics and vascular morphology. This model is used to address dispersion and delay of the arterial input function (AIF) at different levels of the vascular structure and to estimate the local AIF in DCE images. We developed a method based on the simplex algorithm and Akaike information criterion to estimate the likelihood of the contrast agent concentration signal sampled in DCE images belonging to different layers of the vascular tree or being a combination of different signal levels from different nodes of this structure...
February 17, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28211961/an-extended-vascular-model-for-less-biased-estimation-of-permeability-parameters-in-dce-t1-images
#20
Siamak P Nejad-Davarani, Hassan Bagher-Ebadian, James R Ewing, Douglas C Noll, Tom Mikkelsen, Michael Chopp, Quan Jiang
One of the key elements in dynamic contrast enhanced (DCE) image analysis is the arterial input function (AIF). Traditionally, in DCE studies a global AIF sampled from a major artery or vein is used to estimate the vascular permeability parameters; however, not addressing dispersion and delay of the AIF at the tissue level can lead to biased estimates of these parameters. To find less biased estimates of vascular permeability parameters, a vascular model of the cerebral vascular system is proposed that considers effects of dispersion of the AIF in the vessel branches, as well as extravasation of the contrast agent (CA) to the extravascular-extracellular space...
February 17, 2017: NMR in Biomedicine
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