8,795 research outputs found
Development of a Computationally Efficient Fabric Model for Optimization of Gripper Trajectories in Automated Composite Draping
An automated prepreg fabric draping system is being developed which consists
of an array of actuated grippers. It has the ability to pick up a fabric ply
and place it onto a double-curved mold surface. A previous research effort
based on a nonlinear Finite Element model showed that the movements of the
grippers should be chosen carefully to avoid misplacement and induce of
wrinkles in the draped configuration. Thus, the present study seeks to develop
a computationally efficient model of the mechanical behavior of a fabric based
on 2D catenaries which can be used for optimization of the gripper
trajectories. The model includes bending stiffness, large deflections, large
ply shear and a simple contact formulation. The model is found to be quick to
evaluate and gives very reasonable predictions of the displacement field
A simple colorimetric sensor for biologically important anions based on intramolecular charge transfer (ICT)
A sensitive colorimetric sensor (1) based on 4,5-dinitrobenzene-1,2-diamine was designed and synthesized. Binding of anions such as AcO(-), F(-) and H(2)PO(4)(-) results in a notable change in the visible region of spectrum (an approximately 90 nm red shift), which can be detected by the 'naked-eye'. Furthermore, the binding ability was evaluated by UV-vis titration experiments as following: AcO(-) > F(-) > H(2)PO(4) >> Cl(-), Br(-), I(-). The nature of the color change of I induced by AcO(-) was due to the intramolecular charge transfer (ICT) which was confirmed by X-ray crystal structure and (1)H NMR titration spectra. (c) 2009 Elsevier B.V. All rights reserved
Colorimetric and fluorogenic anion sensors of 2 '-(p-nitrophenyl)-imidazol[4 ',5 '-f]-1, 10-phenanthroline[5,6-f] and its complex of Ru(bipy)(2)(2+)
2'-(p-nitrophenyl)-imidazol[4',5'-f]-1,10-phenanthroline[5,6-f] (1) and its [image omitted] complex (2) were synthesised and studied for the anion sensing by UV-vis, fluorescence and H-1 NMR titration experiments. Compounds 1 and 2 exhibited obviously different changes between reactions with AcO-, F-, H2PO4- and with other halogens, i.e. Cl-, Br-, I-, in any of the UV-vis, fluorescence and H-1 NMR titration spectra in DMSO experiments. With an 89nm red shift, 1 was convenient to be employed to detect anions with the naked eye. Complexed with the electron withdrawing metal ion, 2 had the stronger interaction with anions to be detected than 1 had
Inter-Ethnic/Racial Facial Variations: A Systematic Review and Bayesian Meta-Analysis of Photogrammetric Studies
Background
Numerous facial photogrammetric studies have been published around the world. We aimed to critically review these studies so as to establish population norms for various angular and linear facial measurements; and to determine inter-ethnic/racial facial variations.
Methods and Findings
A comprehensive and systematic search of PubMed, ISI Web of Science, Embase, and Scopus was conducted to identify facial photogrammetric studies published before December, 2014. Subjects of eligible studies were either Africans, Asians or Caucasians. A Bayesian hierarchical random effects model was developed to estimate posterior means and 95% credible intervals (CrI) for each measurement by ethnicity/race. Linear contrasts were constructed to explore inter-ethnic/racial facial variations. We identified 38 eligible studies reporting 11 angular and 18 linear facial measurements. Risk of bias of the studies ranged from 0.06 to 0.66. At the significance level of 0.05, African males were found to have smaller nasofrontal angle (posterior mean difference: 8.1°, 95% CrI: 2.2°–13.5°) compared to Caucasian males and larger nasofacial angle (7.4°, 0.1°–13.2°) compared to Asian males. Nasolabial angle was more obtuse in Caucasian females than in African (17.4°, 0.2°–35.3°) and Asian (9.1°, 0.4°–17.3°) females. Additional inter-ethnic/racial variations were revealed when the level of statistical significance was set at 0.10.
Conclusions
A comprehensive database for angular and linear facial measurements was established from existing studies using the statistical model and inter-ethnic/racial variations of facial features were observed. The results have implications for clinical practice and highlight the need and value for high quality photogrammetric studies.published_or_final_versio
Representativeness of breast cancer cases in an integrated health care delivery system.
BackgroundIntegrated health care delivery systems, with their comprehensive and integrated electronic medical records (EMR), are well-poised to conduct research that leverages the detailed clinical data within the EMRs. However, information regarding the representativeness of these clinical populations is limited, and thus the generalizability of research findings is uncertain.MethodsUsing data from the population-based California Cancer Registry, we compared age-adjusted distributions of patient and neighborhood characteristics for three groups of breast cancer patients: 1) those diagnosed within Kaiser Permanente Northern California (KPNC), 2) non-KPNC patients from NCI-designated cancer centers, and 3) those from all other hospitals.ResultsKPNC patients represented 32 % (N = 36,109); cancer center patients represented 7 % (N = 7805); and all other hospitals represented 61 % (N = 68,330) of the total breast cancer patients from this geographic area during 1996-2009. Compared with cases from all other hospitals, KPNC had slightly fewer non-Hispanic Whites (70.6 % versus 74.4 %) but more Blacks (8.1 % versus 5.0 %), slightly more patients in the 50-69 age range and fewer in the younger and older age groups, a slightly lower proportion of in situ but higher proportion of stage I disease (41.6 % versus 38.9 %), were slightly less likely to reside in the lowest (4.2 % versus 6.5 %) and highest (36.2 % versus 39.0 %) socioeconomic status neighborhoods, and more likely to live in suburban metropolitan areas and neighborhoods with more racial/ethnic minorities. Cancer center patients differed substantially from patients from KPNC and all other hospitals on all characteristics assessed. All differences were statistically significant (p < .001).ConclusionsAlthough much of clinical research discoveries are based in academic medical centers, patients from large, integrated medical centers are likely more representative of the underlying population, providing support for the generalizability of cancer research based on electronic data from these centers
Research on Artificial Intelligence Ethics Based on the Evolution of Population Knowledge Base
The unclear development direction of human society is a deep reason for that
it is difficult to form a uniform ethical standard for human society and
artificial intelligence. Since the 21st century, the latest advances in the
Internet, brain science and artificial intelligence have brought new
inspiration to the research on the development direction of human society.
Through the study of the Internet brain model, AI IQ evaluation, and the
evolution of the brain, this paper proposes that the evolution of population
knowledge base is the key for judging the development direction of human
society, thereby discussing the standards and norms for the construction of
artificial intelligence ethics.Comment: 12 pages, 6 figures,1 tabl
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Psychometric evaluation of the Persian Internet Disorder Scale among adolescents
Background and aims:
Given the growing epidemiological research interest concerning Internet addiction, brief instruments with a robust theoretical basis are warranted. The Internet Disorder Scale (IDS-15) is one such instrument that can be used to quickly assess the Internet addiction in an individual. However, only two language versions of the IDS-15 have been developed. This study translated the IDS-15 into Persian and examined its psychometric properties using comprehensive psychometric testing.
Methods:
After ensuring the linguistic validity of the Persian IDS-15, 1,272 adolescents (mean age = 15.53 years; 728 males) completed the IDS-15, Depression Anxiety Stress Scale (DASS), Internet Gaming Disorder Scale – Short Form (IGDS9-SF), and the Bergen Social Media Addiction Scale (BSMAS). Confirmatory factor analysis (CFA), Rasch models, regression analysis, and latent profile analysis (LPA) were carried out to test the psychometric properties of the Persian IDS-15.
Results:
Both CFA and Rasch supported the construct validity of the Persian IDS-15. Multigroup analysis in CFA and differential item functioning in Rasch indicated that male and female adolescents interpreted the IDS-15 items similarly. Regression analysis showed that the IDS-15 correlated with IGDS9-SF and BSMAS (ΔR2 = .12 and .36, respectively) is stronger than the DASS (ΔR2 = .03–.05). LPA based on IDS-15 suggests three subgroups for the sample. Significant differences in depression, anxiety, IGDS9-SF, and BSMAS were found among the three LPA subgroups.
Conclusion:
The Persian IDS-15 has robust psychometric properties as evidenced by both classical test theory and Rasch analysis
Effects of Glucose Concentration on Propofol Cardioprotection against Myocardial Ischemia Reperfusion Injury in Isolated Rat Hearts
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