MSurvPow: a FORTRAN program to calculate the sample size and power for cluster-randomized clinical trials with survival outcomes

Manatunga and Chen [A.K. Manatunga, S. Chen, Sample size estimation for survival outcomes in cluster-randomized studies with small cluster sizes, Biometrics 56 (2000) 616-621] proposed a method to estimate sample size and power for cluster-randomized studies where the primary outcome variable was survival time. The sample size formula was constructed by considering a bivariate marginal distribution (Clayton-Oakes model) with univariate exponential marginal distributions. In this paper, a user-friendly FORTRAN 90 program was provided to implement this method and a simple example was used to illustrate the features of the program.     

Graphene oxide/ferrofluid/cement composites for electromagnetic interference shielding application

This paper deals with the preparation of graphene oxide-ferrofluid-cement nanocomposites to evaluate the electromagnetic interference (EMI) shielding effectiveness (SE) in the 8.2-12.4 GHz frequency range. It has been observed that incorporation of graphene oxide (30 wt%) along with an appropriate amount of ferrofluid in the cement matrix leads to a shielding effectiveness of 46 dB (>99% attenuation).The presence of graphene oxide and ferrofluid in the cement leads to strong polarizations and magnetic losses that consequently result in higher shielding effectiveness compared to pristine cement. The resulting nanocomposites have shown Shore hardness of 54 and dc conductivity of 10.40 S cm( - 1). SEM reveals the homogeneous dispersion of graphene oxide and ferrofluid in the cement matrix.     

Bright red electroluminescence in diffused porous siliconp-n junction

We report the first operation of light emittingp-n junction diode in porous silicon fabricated by diffusion.     

Evaluation of solar fraction (Fn) for quonset type empty greenhouse: an experimental validation

In this study, the experiments were conducted from December 2000 to November 2001 to evaluate solar fraction (F_n) for quonset type empty greenhouse. Solar radiation was measured at different points inside and outside the greenhouse weekly once. The model based on Auto-CAD 2000 has been used for a given solar altitude and azimuth angles. Calculations have also been carried out for a typical day of each month of the year. It is observed that the solar fraction obtained by using Auto-CAD 2000 are very close to the value determined by using experimental observations and its value is more during winter months. Copyright © 2002 John Wiley & Sons, Ltd.     

Nature in Hindu art, architecture and landscape

The article explores the Hindu attitudes towards nature as discerned through art, architecture and landscape. In this transcendental view, nature is seen as manifestation of divinity. The symbolic meanings of natural elements such as tree, mountain, water, and earth in religious thought are described. These meanings form a basis on which the order of nature is represented as a cosmic ideal within sacred landscape and architecture. In the arts and literature, continuity between the natural and human world is expressed as a consequence of natural elements being anthropomorphised as gods and goddesses. Hindu tradition therefore shows little of the duality between nature and culture which is encountered in some other traditions.     

Finite element analysis of piezoelectric thin film membrane structures

Thin film structures have found a wide variety of applications in electromechanical technologies. As the design flexibility for these structures increases, so does the demand for design software that can provide some good insights into the behavior of the structure before it is fabricated. In this study, a finite element code based on a combination of equivalent single-plate theory and classical laminated plate theory was used to predict the dynamic response of thin film structures in micro length scale. As a benchmark for the code development, thin film structures were also fabricated using MEMS technology, and their fundamental frequencies were characterized. It was demonstrated that the model predictions matched fairly well with the experimental data for the small membranes with widths less than 200 microm, but underestimated them for large ones with widths greater than 500 microm. The model also demonstrated that the fundamental frequencies increased with the thickness of the layers. The areas that need to be investigated further in order to improve the predicative capability of the calculations include effects of residual stress, dc bias voltage, parasitic capacitance, interaction of membrane vibration with the supports of the structure, and accurate measurement of the dimensions and material properties of the thin films.     

Insights into the Host Specificity of a New Oomycete Root Pathogen,Pythium brassicum P1: Whole Genome Sequencing and Comparative Analysis Reveals Contracted Regulation of Metabolism,Protein Families,and Distinct Pathogenicity Repertoire

Pythium brassicum P1 Stanghellini, Mohammadi, Förster, and Adaskaveg is an oomycete root pathogen that has recently been characterized. It only attacks plant species belonging to Brassicaceae family, causing root necrosis, stunting, and yield loss. Since P. brassicum P1 is limited in its host range, this prompted us to sequence its whole genome and compare it to those of broad host range Pythium spp. such as P. aphanidermatum and P. ultimum var. ultimum. A genomic DNA library was constructed with a total of 374 million reads. The sequencing data were assembled using SOAPdenovo2, yielding a total genome size of 50.3 Mb contained in 5434 scaffolds, N50 of 30.2 Kb, 61.2% G+C content, and 13,232 putative protein-coding genes. Pythium brassicum P1 had 175 species-specific gene families, which is slightly below the normal average. Like P. ultimum, P. brassicum P1 genome did not encode any classical RxLR effectors or cutinases, suggesting a significant difference in virulence mechanisms compared to other oomycetes. Pythium brassicum P1 had a much smaller proportions of the YxSL sequence motif in both secreted and non-secreted proteins, relative to other Pythium species. Similarly, P. brassicum P1 had the fewest Crinkler (CRN) effectors of all the Pythium species. There were 633 proteins predicted to be secreted in the P. brassicum P1 genome, which is, again, slightly below average among Pythium genomes. Pythium brassicum P1 had only one cadherin gene with calcium ion-binding LDRE and DxND motifs, compared to Pythium ultimum having four copies. Pythium brassicum P1 had a reduced number of proteins falling under carbohydrate binding module and hydrolytic enzymes. Pythium brassicum P1 had a reduced complement of cellulase and pectinase genes in contrast to P. ultimum and was deficient in xylan degrading enzymes. The contraction in ABC transporter families in P. brassicum P1 is suggested to be the result of a lack of diversity in nutrient uptake and therefore host range.     

Structural and Functional Insights into the Transmembrane Domain Association of Eph Receptors

Eph receptors are the largest family of receptor tyrosine kinases and by interactions with ephrin ligands mediate a myriad of processes from embryonic development to adult tissue homeostasis. The interaction of Eph receptors, especially at their transmembrane (TM) domains is key to understanding their mechanism of signal transduction across cellular membranes. We review the structural and functional aspects of EphA1/A2 association and the techniques used to investigate their TM domains: NMR, molecular modelling/dynamics simulations and fluorescence. We also introduce transmembrane peptides, which can be used to alter Eph receptor signaling and we provide a perspective for future studies.     

MR imaging of the prostate in clinical practice

Magnetic resonance imaging (MRI) is the imaging tool of choice in the evaluation of prostate cancer. The main applications of MR imaging in the management of prostate cancer are: (1) to guide targeted biopsy when prostate cancer is clinically suspected and previous ultrasound-guided biopsy results are negative; (2) to localize and stage prostate cancer and provide a roadmap for treatment planning; and (3) to detect residual or locally recurrent cancer after treatment. Other MR techniques such as proton MR spectroscopic imaging (MRSI), diffusion-weighted imaging (DWI), and contrast-enhanced MRI (CE-MRI) complement conventional MR imaging by providing metabolic and functional information that can improve the accuracy of prostate cancer detection and characterization. In everyday clinical practice, and to account for patient comfort, MR imaging studies are limited to 1 h. To obtain consistently high-quality images, a well-designed protocol is necessary. Routine MR imaging can be supplemented by other MR techniques such as MRSI, DWI or CE-MRI depending on the expertise available and the clinical questions that need to be answered. This review summarizes the role of MR imaging in the management of prostate cancer and describes practical approaches to implementing anatomic, metabolic and functional MR imaging techniques in the clinic.