423 research outputs found
Systems of Care for addressing the traumatic impact of violence exposure on student well-being
Our presentation addresses mental health needs of youth from concentrated poverty and exposure to violence. We describe the Systems of Care model and recommend a framework for implementation within school, family and community based settings. Topics include mental health, environmental trauma, poverty, and youth cultural violence. Target Audience: educators, school- and community-based counselors & support staff, social workers, and educational researchers
Determining Predictor Importance In Multiple Regression Under Varied Correlational And Distributional Conditions
This study examines the performance of eight methods of predictor importance under varied correlational and distributional conditions. The proportion of times a method correctly identified the dominant predictor was recorded. Results indicated that the new methods of importance proposed by Budescu (1993) and Johnson (2000) outperformed commonly used importance methods
Genome analysis of a highly virulent serotype 1 strain of streptococcus pneumoniae from West Africa
Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and bacteremia, estimated to cause 2 million deaths annually. The majority of pneumococcal mortality occurs in developing countries, with serotype 1 a leading cause in these areas. To begin to better understand the larger impact that serotype 1 strains have in developing countries, we characterized virulence and genetic content of PNI0373, a serotype 1 strain from a diseased patient in The Gambia. PNI0373 and another African serotype 1 strain showed high virulence in a mouse intraperitoneal challenge model, with 20% survival at a dose of 1 cfu. The PNI0373 genome sequence was similar in structure to other pneumococci, with the exception of a 100 kb inversion. PNI0373 showed only15 lineage specific CDS when compared to the pan-genome of pneumococcus. However analysis of non-core orthologs of pneumococcal genomes, showed serotype 1 strains to be closely related. Three regions were found to be serotype 1 associated and likely products of horizontal gene transfer. A detailed inventory of known virulence factors showed that some functions associated with colonization were absent, consistent with the observation that carriage of this highly virulent serotype is unusual. The African serotype 1 strains thus appear to be closely related to each other and different from other pneumococci despite similar genetic content
Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns
Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased
Serum Vitamin D, PTH, and Calcium Levels in Patients with and without Early Childhood Caries
Purpose: The purpose was to determine differences in serum vitamin D, parathyroid hormone (PTH), and calcium levels between patients with early childhood caries (ECC) and patients without dental decay.
Materials and Methods: Serum vitamin D, PTH, and calcium levels were obtained from 30 children without dental decay who acted as controls and 60 children with ECC. A questionnaire was filled out by the parent/guardian of each participant consisting of questions regarding medical and dental history, exposure to sources of vitamin D and demographic information.
Results: The difference in the vitamin D levels of the participants was most strongly associated with race. African American participants demonstrated lower levels of vitamin D than non-African Americans. After adjusting for race- related differences there was no significant difference in the Vitamin D levels in the ECC cases and the healthy controls.
Conclusions: The results of this study suggest that vitamin D levels, at least among non-African Americans, are unrelated to caries development. Future research in this area must control for important confounding factors such as skin pigmentation, season of measurement of serum vitamin D, sun exposure, fluoride exposure, water fluoridation status and tooth brushing in order to allow for vitamin D levels to be better tested against caries experience
Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows
Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg
Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity
ABSTRACT Despite years of successful isolation of Vibrio vulnificus from estuarine waters, beginning in 2007, it was extremely difficult to culture V. vulnificus from either North Carolina estuarine water or oyster samples. After employing culture-based methods as well as PCR and quantitative PCR for the detection of V. vulnificus , always with negative results, we concluded that this pathogen had become nearly undetectable in the North Carolina estuarine ecosystem. We ensured that the techniques were sound by seeding North Carolina oysters with V. vulnificus and performing the same tests as those previously conducted on unadulterated oysters. V. vulnificus was readily detected in the seeded oysters using both classes of methods. Furthermore, oysters were obtained from the Gulf of Mexico, and V. vulnificus was easily isolated, confirming that the methodology was sound but that the oysters and waters of North Carolina were lacking the V. vulnificus population studied for decades. Strikingly, the apparent loss of detectable V. vulnificus coincided with the most severe drought in the history of North Carolina. The drought continued until the end of 2009, with an elevated water column salinity being observed throughout this period and with V. vulnificus being nearly nonexistent. When salinities returned to normal after the drought abated in 2010, we were again able to routinely isolate V. vulnificus from the water column, although we were still unable to culture it from oysters. We suggest that the oysters were colonized with a more salt-tolerant bacterium during the drought, which displaced V. vulnificus and may be preventing recolonization
Covalent Crosslinking of Carbon Nanotube Materials for Improved Tensile Strength
Carbon nanotubes have attracted much interest in recent years due to their exceptional mechanical properties. Currently, the tensile properties of bulk carbon nanotube-based materials (yarns, sheets, etc.) fall far short of those of the individual nanotube elements. The premature failure in these materials under tensile load has been attributed to inter-tube sliding, which requires far less force than that needed to fracture individual nanotubes.1,2 In order for nanotube materials to achieve their full potential, methods are needed to restrict this tube-tube shear and increase inter-tube forces.Our group is examining covalent crosslinking between the nanotubes as a means to increase the tensile properties of carbon nanotube materials. We are working with multi-walled carbon nanotube (MWCNT) sheet and yarn materials obtained from commercial sources. Several routes to functionalize the nanotubes have been examined including nitrene, aryl diazonium, and epoxide chemistries. The functional nanotubes were crosslinked through small molecule or polymeric bridges. Additionally, electron beam irradiation induced crosslinking of the non-functional and functional nanotube materials was conducted. For example, a nanotube sheet material containing approximately 3.5 mol amine functional groups exhibited a tensile strength of 75 MPa and a tensile modulus of 1.16 GPa, compared to 49 MPa and 0.57 GPa, respectively, for the as-received material. Electron beam irradiation (2.2x 1017 ecm2) of the same amine-functional sheet material further increased the tensile strength to 120 MPa and the modulus to 2.61 GPa. This represents approximately a 150 increase in tensile strength and a 360 increase in tensile modulus over the as-received material with only a 25 increase in material mass. Once we have optimized the nanotube crosslinking methods, the performance of these materials in polymer matrix composites will be evaluated
Association between monosodium glutamate intake and sleep-disordered breathing among Chinese adults with normal body weight
ObjectiveTo assess whether monosodium glutamate (MSG) intake is associated with sleep-disordered breathing (SDB).MethodsData from 1227 Chinese subjects who participated in the Jiangsu Nutrition Study were analyzed. All the participants were examined at two time points (baseline in 2002 and follow-up in 2007). The MSG intake was assessed quantitatively in 2002 and a sleep questionnaire was used to assess snoring and to construct an SDB probability score in 2007. Those within the fifth quintile of the score (highest) were defined as having a high probability of SDB.ResultsThe MSG intake was positively associated with snoring and a high probability of SDB in participants who had a normal body weight but in those who were overweight. A comparison of the extreme quartiles of MSG intake in subjects with a body mass index lower than 23 kg/m² showed an odds ratio of 2.02 (95% confidence interval 1.02-4.00) for snoring and an odds ratio of 3.11 (95% confidence interval 1.10-8.84) for a high probability of SDB. There was a joint effect between MSG and overweight in relation to SDB.ConclusionThe intake of MSG may increase the risk of SDB in Chinese adults with a normal body weight.Zumin Shi, Gary A. Wittert, Baojun Yuan, Yue Dai, Tiffany K. Gill, Gang Hu, Robert Adams, Hui Zuo, Anne W. Taylo
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