Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs) carbon fiber (CF) fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz). The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE) from -29.4 dB for CF/epoxy-composite to -51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported Licens

Quality of life and its determinants in adult cancer patients undergoing chemotherapy treatment in Pakistan.

Objective: Cancer is a leading cause of death worldwide. Likewise, in Pakistan, it is a major health problem, with an approximate increase each year. Cancer treatment, particularly chemotherapy, produces a detrimental effect on individuals\u27 well-being. Since the past few years, quality of life (QOL) is considered as the primary goal of cancer treatment in patients\u27 survival. This study aimed to assess the QOL and its determinants in adult cancer patients undergoing chemotherapy treatment. Methods: An analytical cross-sectional design was employed to achieve the study objectives, utilizing consecutive sampling technique. A total of 150 adult (\u3e19 years) cancer patients were recruited from a Tertiary Care Hospital in Karachi, Pakistan. The data were collected using the Functional Assessment of Cancer Therapy-General, a QOL questionnaire. Multiple linear regression was run to determine the effect of predictor variables, with a mean QOL score. Results: The overall mean score of QOL as 57.37. The domains of physical and emotional well-being were mainly affected by the chemotherapy treatment. Variables such as no previous hospitalization and no significant changes in life events were positively associated with the QOL. On the other hand, being female, unemployed, chemotherapy side effects (\u3e1 week), impaired socialization, and discrimination by family/relatives were negatively associated with the QOL. Conclusions: The study findings suggested an overall low QOL among adult cancer patients undergoing chemotherapy treatment. It is recognized as a stressful treatment, which adversely affects the QOL of cancer patients. Interventions should focus on both the physical and psychological issues and need to be addressed to improve the QOL of adult cancer patients

The loci recommended as universal barcodes for plants on the basis of floristic studies may not work with congeneric species as exemplified by DNA barcoding of Dendrobium species

<p>Abstract</p> <p>Background</p> <p>Based on the testing of several loci, predominantly against floristic backgrounds, individual or different combinations of loci have been suggested as possible universal DNA barcodes for plants. The present investigation was undertaken to check the applicability of the recommended locus/loci for congeneric species with <it>Dendrobium </it>species as an illustrative example.</p> <p>Results</p> <p>Six loci, <it>matK, rbcL, rpoB, rpoC1, trnH-psbA </it>spacer from the chloroplast genome and ITS, from the nuclear genome, were compared for their amplification, sequencing and species discrimination success rates among multiple accessions of 36 <it>Dendrobium </it>species. The <it>trnH-psbA </it>spacer could not be considered for analysis as good quality sequences were not obtained with its forward primer. Among the tested loci, ITS, recommended by some as a possible barcode for plants, provided 100% species identification. Another locus, <it>matK</it>, also recommended as a universal barcode for plants, resolved 80.56% species. ITS remained the best even when sequences of investigated loci of additional <it>Dendrobium </it>species available on the NCBI GenBank (93, 33, 20, 18 and 17 of ITS, <it>matK, rbcL, rpoB </it>and <it>rpoC1</it>, respectively) were also considered for calculating the percent species resolution capabilities. The species discrimination of various combinations of the loci was also compared based on the 36 investigated species and additional 16 for which sequences of all the five loci were available on GenBank. Two-locus combination of <it>matK+rbcL </it>recommended by the Plant Working Group of Consortium for Barcoding of Life (CBOL) could discriminate 86.11% of 36 species. The species discriminating ability of this barcode was reduced to 80.77% when additional sequences available on NCBI were included in the analysis. Among the recommended combinations, the barcode based on three loci - <it>matK, rpoB </it>and <it>rpoC1</it>- resolved maximum number of species.</p> <p>Conclusions</p> <p>Any recommended barcode based on the loci tested so far, is not likely to provide 100% species identification across the plant kingdom and thus is not likely to act as a universal barcode. It appears that barcodes, if based on single or limited locus(i), would be taxa specific as is exemplified by the success of ITS among <it>Dendrobium </it>species, though it may not be suitable for other plants because of the problems that are discussed.</p

Association Between Homocysteine and Vascular Calcification Incidence, Prevalence, and Progression in the MESA Cohort.

Background While elevated homocysteine has been associated with calcification in several studies, its importance as a cardiovascular risk factor remains unclear. This study examines the relationship between homocysteine and vascular and valve calcification in the MESA (Multi-ethnic Study of Atherosclerosis) cohort. Methods and Results MESA participants with baseline homocysteine measurements and cardiac computed tomography scans were included (N=6789). Baseline and follow-up assessment of vascular (coronary artery [CAC], descending thoracic aorta [DTAC]) and valve (aortic valve [AVC], mitral annular [MAC]) calcification was performed. Prevalence ratio/relative risk regression was used to assess the relationship of homocysteine with prevalent and incident calcification, and multivariable logistic regression was used to assess associations between homocysteine and calcification progression. Elevated homocysteine was associated with greater relative risk of prevalent and incident CAC and incident DTAC. We also identified a strong association between elevated homocysteine and CAC and DTAC progression. Elevated homocysteine was found to confer a &gt;2-fold increased risk of severe CAC progression (defined as ΔCAC ≥100/year) and an ≈1.5-fold increased risk for severe DTAC progression (defined as ΔDTAC ≥100/year). Conclusions To our knowledge, this is the first study demonstrating an association between elevated homocysteine and both incidence and progression of coronary and extra-coronary vascular calcification. Our findings suggest a potential role for elevated homocysteine as a risk factor for severe vascular calcification progression. Future studies are warranted to further assess the utility of homocysteine as a biomarker for vascular calcification incidence and progression. Clinical Trial Registration https://www.clinicaltrials.gov/. Unique identifier: NCT00005487

Energy and Climate Change Issues Around CSUDH

Climate change is posing significant challenges to California’s energy sector. Extreme weather events (heat and cold) may pressure existing infrastructure. Many studies have indicated that extreme climate events would impact the energy system by affecting peak electricity demand. However, very few studies have been conducted to understand how disadvantaged communities (DACs) will be impacted. Because of unequal access to energy infrastructure (electricity generation and battery storage), DACs are more vulnerable to power outages due to the rising number of significant weather events caused by climate change. To address the issue of how DACs are disproportionately affected by climate change-related energy issues, we used DACs, infrastructure, and climate data. We identified the most vulnerable communities associated with climate change-related energy issues in areas around California State University Dominguez Hills (CSUDH). This study’s findings will support building the resilience of energy infrastructure to climate change and minimize the energy burden on DACs

Comparative Evaluation of the Accuracy of Placement of Orthodontic Brackets: An In Vitro study

AIM AND OBJECTIVES: To evaluate whether the morphology of orthodontic brackets influences the accuracy of their positioning. The objective of the study was to compare the bracket positioning accuracy among self ligating, ceramic, standard metal conventional ligating and mini metal conventional ligating brackets. MATERIALS AND METHODS: Four operators [2 males and 2 females] with 3+ year experience participated in the study and bonded a total of 560 teeth. Five typodont models were used. One typodont model was employed to determine the ideal position of the brackets. The brackets types used in this investigation were self-ligating, ceramic brackets, standard metal conventional ligating and mini metal conventional ligating brackets. Vertical, horizontal and angular bracket positioning errors were assessed by Corel Draw X8 image analysis software. RESULTS: Bland-Altman analysis showed no evidence of bias and minimal random error. The results from the present study showed that the positioning errors were greatest for self ligating brackets. The standard master AO conventional ligating brackets were the most accurately placed bracket type. Among the self ligating ones, Damon Q self- ligating brackets were the most accurately place ones. Among the ceramic brackets, 3M Clarity Advanced ceramic brackets showed more positioning accuracy. The differences relating to vertical positioning error were not statistically significant (p > 0.05). CONCLUSION: Morphology of the orthodontic brackets influences the accuracy of their positioning. Positioning errors were more in self ligating brackets, less in ceramic brackets, followed by mini metal conventional ligating brackets and standard metal conventional ligating brackets in descending order

CT imaging and staging of carcinoma oesophagus

Background: Over the past decades, computerized tomography (CT) technology has led to an early detection of cancers and thereby decreasing mortality rate. The objective was to demonstrate usefulness of Toshiba Activion 16 slice multi detector computerized tomography (MDCT) scan in staging of oesophageal cancer.Methods: The study was carried out in the Department of Radio diagnosis, Bapuji Hospital and Chigateri Government Hospital attached to Jagadguru Jayadeva Murugarajendra Medical College, Davangere, Karnataka, India over a period of 24 months. After taking a properly informed written consent, complete history and thorough clinical examination was done and these patients were subjected to CT scan.Results: The total numbers of patients studied in present study were 25. Out of which 10 were males and 15 were females. There were 6 patients upto the age of 54 years and 8 patients equal to or greater than 65 years of age, there were 11 patients between 55-64 years of age. Dysphagia was the most common symptom in patients and was present in all the 25 patients of present study. Other common symptoms were weight loss followed by pain in throat. Two different types of wall thickenings of the involved portion have been reported. The most common asymmetrical wall thickening was observed in maximum number of patients 18 (72%) and circumferential wall thickening was observed only in 7 number (28%) of patients out of 25 total patients showing heterogeneous/homogeneous enhancement. Lower third (40%) and middle third (40%) of the esophagus was the most common site of involvement with regards to location of oesophageal cancer followed by upper third (20%) of the esophagus. Homogeneous wall attenuation was observed in most of the cases accounting for (64%). The other type of wall attenuation noted were heterogeneous (36%).Conclusions: By performing endoscopy uncertainty lies in discrimination of muscular layer from serosal layer in most parts of esophagus. However, by employing MDCT technique separation of 2 layers of esophagus can be better judged.  Therefore, MDCT has been found to be the most valuable and preferential technique for planning operational strategy

Experimental and Numerical Optimization of a Variable-Geometry Ejector in a Transcritical CO2 Refrigeration Cycle

Implementation of an ejector for expansion work recovery in transcritical carbon dioxide (CO2) cycles provides an opportunity to improve the efficiency of these environmentally-friendly refrigeration systems. However, literature outlining an approach to ejector design for a given application is lacking. This paper presents a tool to design a complete ejector applied in a vapor compression cycle. In this work, the developed design tool was validated using experimentally-derived polynomials for air-conditioning conditions. Then, constant values for nozzle and mixing section efficiencies were used as inputs into design tool to broaden the analysis outside of the application boundaries of the experimentally-derived polynomials to study a transcritical CO2 system with an ejector operating in the evaporating temperature and gas cooler pressure in the range of -15 °C to 20 °C and 80 bar to 110 bar, respectively. The design tool allows for the calculation of the motive and suction nozzle throat diameters, the mixing section diameter, and the diffuser outlet diameter, as well as the lengths of each section, to output a full internal geometry of the ejector based on performance requirements. Individual component sub-models are presented within the proposed model structure. The model which forms the basis of the design tool was experimentally validated with a mean absolute error (MAE) between 3% to 4%. Additionally, the sensitivity of the ejector geometry and performance to component efficiencies, operating conditions, and component versus system optimization was investigated. The optimization and parametric studies provided novel insights into the impact of desired efficiency and operating conditions on ejector geometry, thus allowing a designer to make decisions based on the tradeoff between ejector size and performance. For example, as the diffuser length increased by 5.1 mm to obtain an efficiency increase, to obtain a further efficiency increase of the same amount would require a 17.1 mm length increase in diffuser length. Potential model improvements and other future work are also discussed

TCSC-STATCOM Controller for the Voltage Stability Improvement of the Wind Farm Connected to the Grid

The project is about the improvement of voltage stability of the system which has a wind farm connected to the Grid. A combination of TCSC and STATCOM is used in the controller. The controller ensures that the system receives enough reactive power to maintain stability. The simulation model is going to be inbuilt MATLAB/SIMULINK. output voltages of the system without the controller, with each component acting separately and the collaborative control effect of TCSC and STATCOM, will be compared and studied in the simulated model to prove the efficiency of the controller