Mechanically fastened joints in woven fabric composites

Strength analysis for composite bolted joints involves the mating of a stress analysis with an appropriate mode specific failure criterion for each of the primary failure modes. The stress analysis and failure criteria are independent of each other and can be manipulated separately in order to optimize the strength analysis package formed by their coupling. Material properties tests were conducted on rubber toughened graphite-epoxy material to measure the basic strength and stiffness in the warp and fill directions and in shear. Test matrices are summarized for investigations of laminate configuration, stacking sequence, fastener diameter, edge distance, fastener half spacing, laminate thickness, and fastener torque. A three dimensional finite element analysis computer program was written and failure criteria for net tension, shearout, and bearing were determined

Cortical Activity Measured with Low-Intensity Fatiguing Contractions of the Quadriceps Muscle Group

Modulation of force production required during exercise is regulated from various mechanisms in the central and peripheral nervous system. Fatigue is influenced by various mechanics that may hinder the ability to continuously sustain force production. The neural activation patterns of these systems can be recorded as electrical impulses using several non-invasive techniques. The ability to examine these during fatiguing exercise has provided further insight into activation patterns in the central nervous system (i.e., motor and pre-motor cortex) during sustained muscle contractions. Electroencephalography (EEG) has been recently utilized to examine changes associated with central fatigue, but limited advancements in technology for neuromuscular fatigue has inhibited progression in this area of research. PURPOSE:The purpose of this study is to discover the effects of low-intensity muscular fatigue on central mechanisms. METHODS:Following 3 Maximal Voluntary Contractions (MVCs), four lower-body resistance trained males (23yrs.±2, ht.176cm ±6., wt. 89kg ±16.) performed 60 second submaximal (30% MVC) isometric ramp contraction of the knee extension exercise. Knee extensions were performed on a custom-built seat using an S-beam load-cell to measure isometric force production of the quadriceps muscle group. During the fatiguing contractions, participants were encouraged to perform as many trapezoidal ramp contractions (i.e., 30%) as possible, until they could no longer sustain the required force production. Fatigue was established when the participant could no longer maintain the contraction force within 10% for no less than 3 seconds during the isometric hold.Cortical activity was recorded with a 24-electrode electroencephalogram (EEG) soft cap. Once EEG signals were referenced, bandpass filtered, and cleaned, gamma and beta frequency band data and topographic maps were computed for electrodes over the cerebral cortex (C3, Cz, and C4). Two separate repeated measures ANOVAs were used to compare the band’s during the first 3 seconds of the force plateau of the pre and post contractions.RESULTS:There were no significant differences over time in any of the electrodes/bands (p\u3e .05). DISCUSSION:These data indicate that low-intensity muscular fatigue is not mediated by central mechanisms in the C3, C4, Cz electrode spaces in the higher frequency bands (beta and gamma). Future research will examine other central mechanisms that underlie the neural circuit involved in muscular fatigue

Somatotyping of Division I Athletes

Somatotyping has previously examined athletes\u27 genetic morphology. Categorization of somatotyping can be utilized in athletes for specialized, adaptive sports performance. PURPOSE: The purpose of this study was to report somatotyping differences (ectomorph, mesomorph, and endomorph) in selected Division I athletes. METHOD: 39 male football athletes and seven female softball Division I athletes were recruited for this investigation. Height (m), weight (kg), waist-to-hip ratio (cm), and a 4-site skinfold measurement was collected. Skinfold locations were recorded from the triceps (mm), subscapular (mm), supraspinal (mm), and the medial calf (mm). Biepicondylar breadth measures of the humerus (cm), and the femur (cm) were recorded at a respective 90°. Additionally, the girth of the subject’s dominant upper arm (cm) and dominant calf (cm) were recorded. All measurement locations were taken from the Heath-Carter Anthropometric protocol, respectfully. The Heath Carter Somatotype Worksheet consists of a rating scale that is based on a 3-component categorization. All measures are considered when calculating a participant\u27s score. Scores between .5 and 2.5 are low, 3 to 5 are moderate, 5.5 to 7 are high and anything over a 7.5 is considered very high. The first component calculated scores of endomorphy, the second calculated mesomorphy scores, and the last component calculated ectomorph scores. Using these measurements, equations are used to determine a participant’s score to a specific somatotype. The athletes\u27 numbers were then processed and plotted on a 2-D graph plotting the somatotype (X= ectomorph-endomorph, Y=2 x mesomorphy- (endomorphy+ectomorph)). RESULTS: There was a clear indication that somatotyping had variety based on sports and position specialization in football athletes. Football athletes consisted of 6 endomorphs, 30 mesomorphs, and 3 ectomorphs, while softball athletes consisted of 7 meso-endomorphs. CONCLUSION: Due to the anthropometric position differences in male football athletes there was a considerable amount of variety and lack of specificity, while the female softball athletes consisted of a lesser variety in anthropometric measures

Genomic and biological characterization of chiltepin yellow mosaic virus, a new tymovirus infecting Capsicum annuum var. aviculare in Mexico.

The characterization of viruses infecting wild plants is a key step towards understanding the ecology of plant viruses. In this work, the complete genomic nucleotide sequence of a new tymovirus species infecting chiltepin, the wild ancestor of Capsicum annuum pepper crops, in Mexico was determined, and its host range has been explored. The genome of 6,517 nucleotides has the three open reading frames described for tymoviruses, putatively encoding an RNA-dependent RNA polymerase, a movement protein and a coat protein. The 5′ and 3′ untranslated regions have structures with typical signatures of the tymoviruses. Phylogenetic analyses revealed that this new virus is closely related to the other tymoviruses isolated from solanaceous plants. Its host range is mainly limited to solanaceous species, which notably include cultivated Capsicum species. In the latter, infection resulted in a severe reduction of growth, indicating the potential of this virus to be a significant crop pathogen. The name of chiltepin yellow mosaic virus (ChiYMV) is proposed for this new tymovirus

Unlocking the power of big data in new product development

This study explores how big data can be used to enable customers to express unrecognised needs. By acquiring this information, managers can gain opportunities to develop customer-centred products. Big data can be defined as multimedia-rich and interactive low-cost information resulting from mass communication. It offers customers a better understanding of new products and provides new, simplified modes of large-scale interaction between customers and firms. Although previous studies have pointed out that firms can better understand customers’ preferences and needs by leveraging different types of available data, the situation is evolving, with increasing application of big data analytics for product development, operations and supply chain management. In order to utilise the customer information available from big data to a larger extent, managers need to identify how to establish a customer-involving environment that encourages customers to share their ideas with managers, contribute their know-how, fiddle around with new products, and express their actual preferences. We investigate a new product development project at an electronics company, STE, and describe how big data is used to connect to, interact with and involve customers in new product development in practice. Our findings reveal that big data can offer customer involvement so as to provide valuable input for developing new products. In this paper, we introduce a customer involvement approach as a new means of coming up with customer-centred new product development

Metabotropic glutamate receptor 5 as a potential target for smoking cessation

Rationale Most habitual smokers find it difficult to quit smoking because they are dependent upon the nicotine present in tobacco smoke. Tobacco dependence is commonly treated pharmacologically using nicotine replacement therapy or drugs, such as varenicline, that target the nicotinic receptor. Relapse rates, however, remain high and there remains a need to develop novel non-nicotinic pharmacotherapies for the dependence that are more effective than existing treatments. Objective The purpose of this paper is to review the evidence from preclinical and clinical studies that drugs that antagonise the metabotropic glutamate receptor 5 (mGluR5) in the brain are likely to be efficacious as treatments for tobacco dependence. Results Imaging studies reveal that chronic exposure to tobacco smoke reduces the density of mGluR5s in human brain. Preclinical results demonstrate that negative allosteric modulators (NAMs) at mGluR5 attenuate both nicotine self-administration and the reinstatement of responding evoked by exposure to conditioned cues paired with nicotine delivery. They also attenuate the effects of nicotine on brain dopamine pathways implicated in addiction. Conclusions Although mGluR5 NAMs attenuate most of the key facets of nicotine dependence they potentiate the symptoms of nicotine withdrawal. This may limit their value as smoking cessation aids. The NAMs that have been employed most widely in preclinical studies of nicotine dependence have too many \u201coff target\u201d effects to be used clinically. However newer mGluR5 NAMs have been developed for clinical use in other indications. Future studies will determine if these agents can also be used effectively and safely to treat tobacco dependence

Complex chloroplast RNA metabolism: just debugging the genetic programme?

<p>Abstract</p> <p>Background</p> <p>The gene expression system of chloroplasts is far more complex than that of their cyanobacterial progenitor. This gain in complexity affects in particular RNA metabolism, specifically the transcription and maturation of RNA. Mature chloroplast RNA is generated by a plethora of nuclear-encoded proteins acquired or recruited during plant evolution, comprising additional RNA polymerases and sigma factors, and sequence-specific RNA maturation factors promoting RNA splicing, editing, end formation and translatability. Despite years of intensive research, we still lack a comprehensive explanation for this complexity.</p> <p>Results</p> <p>We inspected the available literature and genome databases for information on components of RNA metabolism in land plant chloroplasts. In particular, new inventions of chloroplast-specific mechanisms and the expansion of some gene/protein families detected in land plants lead us to suggest that the primary function of the additional nuclear-encoded components found in chloroplasts is the transgenomic suppression of point mutations, fixation of which occurred due to an enhanced genetic drift exhibited by chloroplast genomes. We further speculate that a fast evolution of transgenomic suppressors occurred after the water-to-land transition of plants.</p> <p>Conclusion</p> <p>Our inspections indicate that several chloroplast-specific mechanisms evolved in land plants to remedy point mutations that occurred after the water-to-land transition. Thus, the complexity of chloroplast gene expression evolved to guarantee the functionality of chloroplast genetic information and may not, with some exceptions, be involved in regulatory functions.</p