Structural properties of impact ices accreted on aircraft structures

The structural properties of ice accretions formed on aircraft surfaces are studied. The overall objectives are to measure basic structural properties of impact ices and to develop finite element analytical procedures for use in the design of all deicing systems. The Icing Research Tunnel (IRT) was used to produce simulated natural ice accretion over a wide range of icing conditions. Two different test apparatus were used to measure each of the three basic mechanical properties: tensile, shear, and peeling. Data was obtained on both adhesive shear strength of impact ices and peeling forces for various icing conditions. The influences of various icing parameters such as tunnel air temperature and velocity, icing cloud drop size, material substrate, surface temperature at ice/material interface, and ice thickness were studied. A finite element analysis of the shear test apparatus was developed in order to gain more insight in the evaluation of the test data. A comparison with other investigators was made. The result shows that the adhesive shear strength of impact ice typically varies between 40 and 50 psi, with peak strength reaching 120 psi and is not dependent on the kind of substrate used, the thickness of accreted ice, and tunnel temperature below 4 C

Dynamic substructuring for shock spectrum analysis using component mode synthesis

Component mode synthesis was used to analyze different types of structures with MSC NASTRAN. The theory and technique of using Multipoint Constraint Equations (MPCs) to connect substructures to each other or to a common foundation is presented. Computation of the dynamic response of the system from shack spectrum inputs was automated using the DMAP programming language of the MSC NASTRAN finite element code

Vibration characteristics of a large wind turbine tower on non-rigid foundations

Vibration characteristics of the Mod-OA wind turbine supported by nonrigid foundations were investigated for a range of soil rigidities. The study shows that the influence of foundation rotation on the fundamental frequency of the wind turbine is quite significant for cohesive soils or loose sand. The reduction in natural frequency can be greater than 20 percent. However, for a foundation resting on well graded, dense granular materials or bedrock, such effect is small and the foundation can be treated as a fixed base

Propriedades psicométricas da Escala de Medida do Estado Atual (MOCS) em pacientes mexicanos com câncer

Background: Cancer is a public health problem, and stress is one of the psychosocial variables associated to this disease, which calls for the need to have a reliable scale to measures stress in the Hispanic population with cancer. Objective: To determine the psychometric properties of the Measurement of Current Status (MOCS) Scale in Mexican cancer patients. Method: Study design: Cross-sectional, non-experimental instrumental. A total of 197 patients aged 18-81 years, at any clinical stage, receiving cancer treatment or follow-up were included. Instruments: MOCS and emotional distress thermometer. Statistical analysis: Confirmatory factor analysis was performed to evaluate the fit of the model to the data using the maximum likelihood estimation and cut-off points. Results: Two models were obtained. The first, self-perceived current state, had an alpha of .90 with an explained variance of 74.2 %; the second, non-specific effect, with an alpha of .61 and an explained variance of 74.3 %. The confirmatory factor analysis showed that both models had indexes suggesting stability and acceptable adjustment. Scores are shown by interquartile ranges for each model. Conclusions: The Mexican version of the MOCS is reliable and valid; with a confirmatory factor structure similar to the original version. Therefore, we support its use in the clinical and research setting with cancer patients.Antecedentes: El cáncer es un problema de salud pública, una de las variables psicosociales en relación con esta enfermedad es el estrés, por tanto es necesario tener una escala que mida el estrés en población hispana con cáncer. Objetivo: Determinar las propiedades psicométricas de la Escala de Medida del Estado Actual (MOCS, por sus igla en inglés) en pacientes mexicanos con cáncer. Método: Estudio transversal, instrumental no experimental. Participaron 197 pacientes de 18 a 81 años, de cualquier etapa clínica, en tratamiento o seguimiento del cáncer. Instrumentos: MOCS y termómetro de malestar emocional. Análisis estadísticos: análisis factorial confirmatorio para evaluar el ajuste del modelo a los datos mediante el método de máxima verosimilitud y puntos de corte. Resultados: Se obtuvieron dos modelos, el primero, estado actual autopercibido, con un alfa de .90 varianza explicada de 74.2 %, el segundo, efectos inespecíficos, con un alfa de .61 varianza explicada de 74.3 %. El análisis factorial confirmatorio mostró que ambos modelos tuvieron índices que sugieren estabilidad, ajuste aceptable, se muestran puntajes mediante rangos intercuartílicos para cada modelo. Conclusiones: la versión mexicana del MOCS tiene confiabilidad y validez, su estructura factorial confirmatoria es similar a la versión original. Se recomienda su uso en la práctica clínica e investigación en pacientes con cáncer.Antecedentes: O câncer é um problema de saúde pública, uma das variáveis psicossociais relacionadas a essa doença é o estresse, portanto, é necessário ter uma escala que meça o estresse na população hispânica com câncer. Objetivo: Determinar as propriedades psicométricas da Escala de Medição do Estado Atual (MOCS) em pacientes mexicanos com câncer. Método: Desenho do estudo: transversal, instrumental, não experimental. Participaram 197 pacientes com idades entre 18 e 81 anos, em qualquer estágio clínico, em tratamento ou acompanhamento do câncer. Instrumentos: MOCS e Termômetro de desconforto emocional. Análises estatísticas: análise fatorial confirmatória para avaliar o ajuste do modelo aos dados por meio do método de máxima verossimilhança e pontos de corte. Resultados: Foram obtidos dois modelos, o primeiro estado atual autopercebido com um alfa de 0,90 variância explicada de 74,2 %, o segundo efeito inespecífico com um alfa de 0,61 variância explicada de 74,3 %; a análise fatorial confirmatória mostrou que ambos os modelos tiveram índices que sugerem estabilidade, ajuste aceitável e são demonstradas pontuações por meio de intervalos interquartis para cada modelo. Conclusões: a versão mexicana do MOCS tem confiabilidade e validade; sua estrutura fatorial confirmatória é semelhante à versão original. É recomendado para prática clínica e pesquisa em pacientes com câncer

The valine and lysine residues in the conserved FxVTxK motif are important for the function of phylogenetically distant plant cellulose synthases

Cellulose synthases (CESAs) synthesize the β-1,4-glucan chains that coalesce to form cellulose microfibrils in plant cell walls. In addition to a large cytosolic (catalytic) domain, CESAs have eight predicted transmembrane helices (TMHs). However, analogous to the structure of BcsA, a bacterial cellulose synthase, predicted TMH5 in CESA may instead be an interfacial helix. This would place the conserved FxVTxK motif in the plant cell cytosol where it could function as a substrate-gating loop as occurs in BcsA. To define the functional importance of the CESA region containing FxVTxK, we tested five parallel mutations in Arabidopsis thaliana CESA1 and Physcomitrella patens CESA5 in complementation assays of the relevant cesa mutants. In both organisms, the substitution of the valine or lysine residues in FxVTxK severely affected CESA function. In Arabidopsis roots, both changes were correlated with lower cellulose anisotropy, as revealed by Pontamine Fast Scarlet. Analysis of hypocotyl inner cell wall layers by atomic force microscopy showed that two altered versions of Atcesa1 could rescue cell wall phenotypes observed in the mutant background line. Overall, the data show that the FxVTxK motif is functionally important in two phylogenetically distant plant CESAs. The results show that Physcomitrella provides an efficient model for assessing the effects of engineered CESA mutations affecting primary cell wall synthesis and that diverse testing systems can lead to nuanced insights into CESA structure/function relationships. Although CESA membrane topology needs to be experimentally determined, the results support the possibility that the FxVTxK region functions similarly in CESA and BcsA

Alternative splicing regulates vesicular trafficking genes in cardiomyocytes during postnatal heart development

During postnatal development the heart undergoes a rapid and dramatic transition to adult function through transcriptional and post-transcriptional mechanisms, including alternative splicing (AS). Here we perform deep RNA-sequencing on RNA from cardiomyocytes and cardiac fibroblasts to conduct a high-resolution analysis of transcriptome changes during postnatal mouse heart development. We reveal extensive changes in gene expression and AS that occur primarily between postnatal days 1 and 28. Cardiomyocytes and cardiac fibroblasts show reciprocal regulation of gene expression reflecting differences in proliferative capacity, cell adhesion functions and mitochondrial metabolism. We further demonstrate that AS plays a role in vesicular trafficking and membrane organization. These AS transitions are enriched among targets of two RNA-binding proteins, Celf1 and Mbnl1, which undergo developmentally regulated changes in expression. Vesicular trafficking genes affected by AS during normal development (when Celf1 is downregulated) show a reversion to neonatal splicing patterns after Celf1 re-expression in adults. Short-term Celf1 induction in adult animals results in disrupted transverse tubule organization and calcium handling. These results identify potential roles for AS in multiple aspects of postnatal heart maturation, including vesicular trafficking and intracellular membrane dynamics.Myotonic Dystrophy Foundation (Postdoctoral Fellowship

Global redox proteome and phosphoproteome analysis reveals redox switch in Akt.

Protein oxidation sits at the intersection of multiple signalling pathways, yet the magnitude and extent of crosstalk between oxidation and other post-translational modifications remains unclear. Here, we delineate global changes in adipocyte signalling networks following acute oxidative stress and reveal considerable crosstalk between cysteine oxidation and phosphorylation-based signalling. Oxidation of key regulatory kinases, including Akt, mTOR and AMPK influences the fidelity rather than their absolute activation state, highlighting an unappreciated interplay between these modifications. Mechanistic analysis of the redox regulation of Akt identified two cysteine residues in the pleckstrin homology domain (C60 and C77) to be reversibly oxidized. Oxidation at these sites affected Akt recruitment to the plasma membrane by stabilizing the PIP3 binding pocket. Our data provide insights into the interplay between oxidative stress-derived redox signalling and protein phosphorylation networks and serve as a resource for understanding the contribution of cellular oxidation to a range of diseases