971 resultados para Myosin Heavy-chain
Resumo:
The extreme diversity of conditions acting on railways necessitates a variety of experimental approaches to study the critical wear mechanisms that present themselves at the contact interface. This work investigates the effects of contact pressure and geometry in rolling-contact wear tests by using discs with different radii of curvature to simulate the varying contact conditions that may be typically found in the field. It is commonly adapted to line contact interface as it has constant contact pressure. But practical scenario of the rail wheel interface, the contact area increase and contact pressure change as tracks worn off. The tests were conducted without any significant amount of traction, but micro slip was still observed due to contact deformation. Moreover, variation of contact pressure was observed due to contact patch elongation and diameter reduction. Rolling contact fatigue, adhesive and sliding wear were observed on the curved contact interface. The development of different wear regimes and material removal phenomena were analysed using microscopic images in order to broaden the understanding of the wear mechanisms occurring in the rail-wheel contact.
Resumo:
This work investigates the effects of contact pressure and geometry in rolling-contact wear tests by using discs with different radii of curvature to simulate the varying contact conditions that may be typically found in the field. The tests were conducted without any significant amount of traction, but micro slip was still observed due to contact deformation. Moreover, variation of contact pressure was observed due to contact patch elongation and diameter reduction. Rolling contact fatigue, adhesive and sliding wear were observed on the curved contact interface. The development of different wear regimes and material removal phenomena were analyzed using microscopic images in order to broaden the understanding of the wear mechanisms occurring in the rail-wheel contact.
Resumo:
The sheep (Ovis aries) is favored by many musculoskeletal tissue engineering groups as a large animal model because of its docile temperament and ease of husbandry. The size and weight of sheep are comparable to humans, which allows for the use of implants and fixation devices used in human clinical practice. The construction of a complimentary DNA (cDNA) library can capture the expression of genes in both a tissue- and time-specific manner. cDNA libraries have been a consistent source of gene discovery ever since the technology became commonplace more than three decades ago. Here, we describe the construction of a cDNA library using cells derived from sheep bones based on the pBluescript cDNA kit. Thirty clones were picked at random and sequenced. This led to the identification of a novel gene, C12orf29, which our initial experiments indicate is involved in skeletal biology. We also describe a polymerase chain reaction-based cDNA clone isolation method that allows the isolation of genes of interest from a cDNA library pool. The techniques outlined here can be applied in-house by smaller tissue engineering groups to generate tools for biomolecular research for large preclinical animal studies and highlights the power of standard cDNA library protocols to uncover novel genes.
Resumo:
With recent economic growth in Oman there is increased use of heavy vehicles, presenting an increase in heavy vehicle crashes, associated fatalities and injuries. Vehicle defects cause a significant number of heavy vehicle crashes in Oman and increase the likelihood of fatalities. The aim of this study is to explore factors contributing to driving with vehicle defects in the Omani heavy vehicle industry. A series of qualitative participants observations were conducted in Oman with 49 drivers. These observations also involved discussion and interviews with drivers. The observations occurred at two road-side locations where heavy vehicle drivers gather for eating, resting, vehicle check-up, etc. Data collection was conducted over a three week period. The data was analysed using thematic analysis. A broad number of factors were identified as contributing to the driving of vehicles with defects. Participants indicated that tyres and vehicle mechanical faults were a common issue in the heavy vehicle industry. Participants regularly reported that their companies use cheap, poor quality standards parts and conducted minimal maintenance. Drivers also indicated that they felt powerless to resist company pressure to drive vehicles with known faults. In addition, drivers reported that traffic police were generally in effective and lacked skill to appropriately conduct roadside inspection on trucks. Further, participants stated that it was possible for companies to avoid being fined during annual or roadside vehicle inspections if members of the company knew the traffic police officer conducting the inspection. Moreover, fines issued by police are generally directed to the individual driver rather than being applied to the company, thus providing no incentive for companies to address vehicle faults. The implications of the findings are discussed.
Resumo:
Inappropriate speed and speeding are among the highest causes of crashes in the heavy vehicle industry. Truck drivers are subjected to a broad range of influences on their behaviour including industrial pressures, company monitoring and police enforcement. Further, drivers have a high level of autonomy over their own behaviour. As such it is important to understand how these external influences interact with commonly shared beliefs, attitudes and values of heavy vehicle drivers to influence their behaviour. The present study uses a re-conceptualisation of safety culture to explore the behaviours of driving at an inappropriate speed and speeding in the heavy vehicle industry. A series of case studies, consisting of interviews and ride-along observations, were conducted with three transport organisations to explore the effect of culture on safety in the heavy vehicle industry. Results relevant to inappropriate speed are reported and discussed. It was found that organisational management through monitoring, enforcement and payment, police enforcement, customer standards and vehicle design factors could all reduce the likelihood of driving at inappropriate speeds under some circumstances. However, due to weaknesses in the ability to accurately monitor appropriate speed, this behaviour was primarily influenced by cultural beliefs, attitudes and values. Truck drivers had a tendency to view speeding as relatively safe, had a desire to speed to save time and increase personal income, and thus often attempted to speed without detection. When drivers saw speeding as dangerous, however, they were more likely to drive safely. Implications for intervention are discussed.
Resumo:
Purpose This paper aims to conduct a systematic review of the literature on supply chain collaboration published over a 10-year period from 2005 to 2014. It explores the nature and extent of research undertaken to identify key themes emerging in the field and gaps that need to be addressed. Design/methodology/approach The authors review a sample of 207 articles from 69 journals, after using an iterative cycle of defining appropriate search keywords, searching the literature and conducting the analysis. Findings Key themes include the meaning of collaboration; considerations for supply chain collaboration theory; emerging areas in collaboration for sustainability, technology-enabled supply chains and humanitarian supply chains; and the need for a more holistic approach, multi-tier perspectives and research into B2C collaborations. Research limitations/implications The paper provides discussion and scope for future research into the area which would contribute to the field tremendously. Originality/value There have been very few reviews in the past on supply chain collaboration, and this is one of the first extensive reviews conducted to address how well the body of knowledge on supply chain collaboration corresponds with our contemporary society.
Resumo:
This paper reports a new class of photo-cross-linkable side chain liquid crystalline polymers (PSCLCPs) based on the bis(benzylidene)cyclohexanone unit, which functions as both a mesogen and a photoactive center. Polymers with the bis(benzylidene)cyclohexanone unit and varying spacer length have been synthesized. Copolymers of bis(benzylidene)cyclohexanone containing monomer and cholesterol benzoate containing monomer with different compositions have also been prepared. All these polymers have been structurally characterized by spectroscopic techniques. Thermal transitions were studied by DSC, and mesophases were identified by polarized light optical microscopy (POM). The intermediate compounds OH-x, the monomers SCLCM-x, and the corresponding polymers PSCLCP-x, which are essentially based on bis(benzylidene)cyclohexanone, all show a nematic mesophase. Transition temperatures were observed to decrease with increasing spacer length. The copolymers with varying compositions exhibit a cholesteric mesophase, and the transition temperatures increase with the cholesteric benzoate units in the copolymer. Photolysis of the low molecular weight liquid crystalline bis(benzylidene)-cyclohexanone compound reveals that there are two kinds of photoreactions in these systems: the EZ photoisomerization and 2 pi + 2 pi addition. The EZ photoisomerization in the LC phase disrupts the parallel stacking of the mesogens, resulting in the transition from the LC phase to the isotropic phase. The photoreaction involving the 2 pi + 2 pi addition of the bis(benzylidene)cyclohexanone units in the polymer results in the cross-linking of the chains. The liquid crystalline induced circular dichroism (LCICD) studies of the cholesterol benzoate copolymers revealed that the cholesteric supramolecular order remains even after the photo-cross-linking.
Resumo:
This project was the first comprehensive assessment of heavy metals to be conducted in the sediments of Northern Moreton Bay since the 1970s and found that shipping and shipping related activities contributed significantly to the level of sediment contamination in the area. The study was also used to develop and test new methods of assessing heavy metal sediment quality.
Resumo:
Two series of thermotropic main chain discotic liquid crystalline polyethers, PR4m-n, based on rufigallol were prepared starting from the symmetric tetraethers of rufigallol, R4m; m and n represent the number of carbon atoms in the side chain and spacer segment, respectively. The symmetric tetraethers were in turn readily prepared by selective alkylation of rufigallol under controlled phase-transfer conditions. GPC analysis of the polymers suggested that they were all of moderate molecular weights, with M-n varying between 5400 and 17 000. The length of the spacer segment n in these polyethers was systematically varied, and its effect on the phase transition temperatures and the mesophase structure was examined using DSC, polarized light microscopy, and X-ray diffraction. It is noticed that when the spacer lengths are relatively long(n greater than or equal to 2m), the isotropization temperature (TD-i) decreases as the spacer length n increases, an observation that is in accordance with those previously made. However, when the spacer lengths are relatively small (n < 2m), the dependence of TD-i is quite the opposite; TD-i actually increases with an increase in spacer length. Furthermore, X-ray diffraction studies indicate that, in the discotic columnar mesophases that are formed, the columns pack in a hexagonal manner when n greater than or equal to 2m, while they do so in a rectangular lattice when n < 2m, leading to the formation of Dh and Dr mesophases, respectively. Finally, comparison of the discotic polyethers with their low molar mass analogues confirms the role of polymerization in stabilizing the mesophase; while all the polymers exhibit columnar mesophases, some of their low molar mass analogues are not liquid crystalline.
Resumo:
This is the first comprehensive report on the calculation of segment size, which signifies the asic unit of flow in long chain plasticizing liquids, by a novel multi-pronged approach. Unlike,low molecular weight liquids and high polymer melts these complex long chain liquids encompasses the least understood domain of the liquid state. In the present work the flow behaviour of carboxylate ester (300-900 Da) has been explained through segmental motion taking into account the independence of molecular weight region. The segment size have been calculated by various methods based on satistical thermodynamics, molecular dynamics and group additivity nd their merits analysed.
Resumo:
A 100,000 x g supernatant fraction prepared from developing groundnut seeds (30-35 days after flowering) catalyzed the synthesis of fatty acids from [l-14C]acetate at a rate of 120nmoles of acetate incorporated per hr per gram fresh weight of tissue. 90% of this incorporated label was associated with fatty acids. The major fatty acids formed were stearic- (77%) and palmitic acids (14%) with 4% of oleic acid. The fatty acid synthetase activity was stable when stored at 0-4 degrees C for at least fifteen days. It is concluded from these results that acetyl-coA carboxylase and all the enzymes of fatty acid synthetase from developing groundnut seeds are soluble.
Resumo:
Malnutrition is common in children with end-stage liver disease (ESLD) awaiting orthotopic liver transplantation (OLT), and nutritional support is assuming an important role in preoperative management. To evaluate preoperative nutritional therapy, 19 children (median age 1.25 y) with ESLD awaiting OLT were prospectively studied. Two high-energy, isoenergetic and isonitrogenous nutritional formulations delivered nasogastrically were compared: a branched-chain amino acid (BCAA)-enriched semielemental formulation and a matched standard semielemental formulation. Twelve of 19 patients completed a randomized controlled study before OLT and 10 of 19 completed a full crossover study. Improvements in weight and height occurred during the BCAA supplements, with no statistical change on the standard formulation. Significant increases in total body potassium, midupper arm circumference, and subscapular skinfold thickness occurred during the BCAA supplements, whereas no significant changes occurred during the standard formulation period. Significantly fewer albumin infusions were required during the BCAA supplement. These findings suggest that BCAA-enriched formulas have advantages over standard semielemental formulas in improving nutritional status in children with ESLD. and are deserving of wider application and study.
Resumo:
Complexes of lanthanide perchlorates with the ligand N,N,N,N-tetra-methyl-3,6,9-trioxaundecane diamide (TUD) of the composition Ln(TUD)2-(ClO4)3 (Ln triple bond; length as m-dash La, Nd, Ho, Er, Y) were isolated. Electrical conductivity values indicate that all the perchlorate groups are ionic. IR and nuclear magnetic resonance (1H and 13C) data prove that the ligand coordinates to the metal via the three ether oxygens and the two carbonyl oxygens. A probable coordination number of ten can be assigned for all the complexes.
Resumo:
This thesis explores melodic and harmonic features of heavy metal, and while doing so, explores various methods of music analysis; their applicability and limitations regarding the study of heavy metal music. The study is built on three general hypotheses according to which 1) acoustic characteristics play a significant role for chord constructing in heavy metal, 2) heavy metal has strong ties and similarities with other Western musical styles, and 3) theories and analytical methods of Western art music may be applied to heavy metal. It seems evident that in heavy metal some chord structures appear far more frequently than others. It is suggested here that the fundamental reason for this is the use of guitar distortion effect. Subsequently, theories as to how and under what principles heavy metal is constructed need to be put under discussion; analytical models regarding the classification of consonance and dissonance and chord categorization are here revised to meet the common practices of this music. It is evident that heavy metal is not an isolated style of music; it is seen here as a cultural fusion of various musical styles. Moreover, it is suggested that the theoretical background to the construction of Western music and its analysis can offer invaluable insights to heavy metal. However, the analytical methods need to be reformed to some extent to meet the characteristics of the music. This reformation includes an accommodation of linear and functional theories that has been found rather rarely in music theory and musicology.
Resumo:
This work was prompted by the need to be able to identify the invasive mussel species, Perna viridis, in tropical Australian seas using techniques that do not rely solely on morphology. DNA-based molecular methods utilizing a polymerase chain reaction (PCR) approach were developed to distinguish unambiguously between the three species in the genus Perna. Target regions were portions of two mitochondrial genes, cox1 and nad4, and the intergenic spacer between these that occurs in at least two Perna species. Based on interspecific sequence comparisons of the nad4 gene, a conserved primer has been designed that can act as a forward primer in PCRs for any Perna species. Four reverse primers have also been designed, based on nad4 and intergenic spacer sequences, which yield species-specific products of different lengths when paired with the conserved forward primer. A further pair of primers has been designed that will amplify part of the cox1 gene of any Perna species, and possibly other molluscs, as a positive control to demonstrate that the PCR is working.