22 resultados para Refrigeration and refrigerating machinery

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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The effect of different pressure levels (500 and 600. MPa for 1. min at ambient temperature) on lasagne ready meal as a means of increasing the safety and shelf life during storage at refrigeration (4. °C) and abuse temperature (8. °C) was investigated. High-pressure processing (500 and 600. MPa for 1. min) was able to significantly reduce the total aerobic and lactic acid bacteria counts and prolong the microbiological shelf life of lasagne at both refrigeration and abuse temperatures. Pressure at 600. MPa was a useful tool to reduce the safety risks associated with Staphylococcus aureus and Listeria monocytogenes. However, abuse storage temperature facilitated the recovery of L. monocytogenes towards the end of storage. Organoleptic evaluation revealed that HPP did not negatively influence the quality attributes of lasagne and prolonged its organoleptic shelf life. HPP treatment can serve as a useful additional step to enhance safety and increase the shelf life of multicomponent ready meals, such as lasagne. Industrial relevance: The ready meals sector of the food industry has been experiencing increasing growth in the past years. This comprehensive study explored the effects of HPP on a very popular multicomponent ready meal i.e., lasagne after treatment and during storage. The results showed that HPP can be successfully applied to lasagne ready meals to decrease the risk from S. aureus and L. monocytogenes and also significantly prolong its shelf life without affecting its organoleptic properties. The utilisation of HPP by the industry can significantly increase safety and also provide the opportunity for this product to reach markets further away.

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The environmental attractions of air-cycle refrigeration are considerable. Following a thermodynamic design analysis, an air-cycle demonstrator plant was constructed within the restricted physical envelope of an existing Thermo King SL200 trailer refrigeration unit. This unique plant operated satisfactorily, delivering sustainable cooling for refrigerated trailers using a completely natural and safe working fluid. The full load capacity of the air-cycle unit at -20 °C was 7,8 kW, 8% greater than the equivalent vapour-cycle unit, but the fuel consumption of the air-cycle plant was excessively high. However, at part load operation the disparity in fuel consumption dropped from approximately 200% to around 80%. The components used in the air-cycle demonstrator were not optimised and considerable potential exists for efficiency improvements, possibly to the point where the air-cycle system could rival the efficiency of the standard vapour-cycle system at part-load operation, which represents the biggest proportion of operating time for most units.

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Efficient synaptic vesicle membrane recycling is one of the key factors required to sustain neurotransmission. We investigated potential differences in the compensatory endocytic machineries in two glutamatergic synapses with phasic and tonic patterns of activity in the lamprey spinal cord. Post-embedding immunocytochemistry demonstrated that proteins involved in synaptic vesicle recycling, including dynamin, intersectin, and synapsin, occur at higher levels (labeling per vesicle) in tonic dorsal column synapses than in phasic reticulospinal synapses. Synaptic vesicle protein 2 occurred at similar levels in the two types of synapse. After challenging the synapses with high potassium stimulation for 30 min the vesicle pool in the tonic synapse was maintained at a normal level, while that in the phasic synapse was partly depleted along with expansion of the plasma membrane and accumulation of clathrin-coated intermediates at the periactive zone. Thus, our results indicate that an increased efficiency of the endocytic machinery in a synapse may be one of the factors underlying the ability to sustain neurotransmission at high rates.

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The performance of an air-cycle refrigeration unit for road transport, which had been previously reported, was analysed in detail and compared with the original design model and an equivalent Thermo King SL200 vapour-cycle refrigeration unit. Poor heat exchanger performance was found to be the major contributor to low coefficient of performance values. Using state-of-the-art, but achievable performance levels for turbomachinery and heat exchangers, the performance of an optimised air-cycle refrigeration unit for the same application was predicted. The power requirement of the optimised air-cycle unit was 7% greater than the equivalent vapour-cycle unit at full-load operation. However, at part-load operation the air-cycle unit was estimated to absorb 35% less power than the vapour-cycle unit. The analysis demonstrated that the air-cycle system could potentially match the overall fuel consumption of the vapour-cycle transport refrigeration unit, while delivering the benefit of a completely refrigerant free system.

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The exact functions of BRCA1 have not been fully described but it now seems apparent that it has roles in DNA damage repair, transcriptional regulation, cell cycle control and most recently in ubiquitylation. These functions of BRCA1 are most likely interdependent but this review will focus on the role of BRCA1 in relation to transcriptional regulation and in particular how this impacts upon cell cycle control. We will (i) describe the structure of BRCA1 and how it may contribute to its transcription function; (ii) describe the interaction of BRCA1 with the core transcriptional machinery (RNA polII); (iii) describe how BRCA1 may regulate transcription at an epigenetic level through chromatin modification; (iv) discuss the role of BRCA1 in modulating transcription through its association with sequence-specific transcription factors. Finally, we will discuss the possible effects of BRCA1 transcriptional regulation on downstream targets with known roles in cell cycle control.

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Using matched employer-employee data from the German LIAB for 2001, the authors found that German works councils are in general associated with higher earnings, even after accounting for establishment- and worker heterogeneity. Works Council wage premia exceed those of collective bargaining and are higher, in fact, where both institutions are present in the workplace. The authors also found evidence indicating that works councils benefit women relative to men and appear to favor foreign, east-German, and service-sector workers as well. Separate evidence from quantile regressions suggests that the conjunction of works council presence and collective bargaining is important to the narrowing process. In smaller plants even the presence of a works council markup depends on the coexistence of the works council entity With the machinery of collective bargaining.

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Purpose – The purpose of this paper is to identify, clarify and tabulate the various managerial issues encountered, to aid in the management of the complex health and safety concerns which occur within a confined construction site environment.

Design/methodology/approach – This is achieved through conducting extensive qualitative and qualitative research in the form of case studies, interviews and questionnaire survey.

Findings – The leading managerial issues in the management of health and safety on a confined construction site are found to be: “Difficulty to move materials around site safely”; “Lack of adequate room for the effective handling of materials”; “Difficulty in ensuring site is tidy and all plant and materials are stored safely”; “Close proximity of individuals to operation of large plant and machinery”; and joint fifth “Difficulty in ensuring proper arrangement and collection of waste materials on-site” along with “Difficulty in controlling hazardous materials and equipment on site”.

Practical implications – The resulting implication for practice of these results can be summarised by identifying that with sustained development of urban centres on a global scale, coupled with the increasing complexity of architectural designs, the majority of on-site project management professionals are faced with the onerous task of completing often intricate designs within a limited spatial environment, under strict health and safety parameters.

Originality/value – The subsequent value of the findings are such that just as on-site management professionals successfully identify the various managerial issues highlighted, the successful management of health and safety on a confined construction site is attainable.

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Cystic fibrosis is the most common inherited lethal disease in Caucasians. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), of which the cftr ?F508 mutation is the most common. ?F508 macrophages are intrinsically defective in autophagy because of the sequestration of essential autophagy molecules within unprocessed CFTR aggregates. Defective autophagy allows Burkholderia cenocepacia (B. cepacia) to survive and replicate in ?F508 macrophages. Infection by B. cepacia poses a great risk to cystic fibrosis patients because it causes accelerated lung inflammation and, in some cases, a lethal necrotizing pneumonia. Autophagy is a cell survival mechanism whereby an autophagosome engulfs non-functional organelles and delivers them to the lysosome for degradation. The ubiquitin binding adaptor protein SQSTM1/p62 is required for the delivery of several ubiquitinated cargos to the autophagosome. In WT macrophages, p62 depletion and overexpression lead to increased and decreased bacterial intracellular survival, respectively. In contrast, depletion of p62 in ?F508 macrophages results in decreased bacterial survival, whereas overexpression of p62 leads to increased B. cepacia intracellular growth. Interestingly, the depletion of p62 from ?F508 macrophages results in the release of the autophagy molecule beclin1 (BECN1) from the mutant CFTR aggregates and allows its redistribution and recruitment to the B. cepacia vacuole, mediating the acquisition of the autophagy marker LC3 and bacterial clearance via autophagy. These data demonstrate that p62 differentially dictates the fate of B. cepacia infection in WT and ?F508 macrophages.

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Signal initiation by engagement of the TCR triggers actin rearrangements, receptor clustering, and dynamic organization of signaling complexes to elicit and sustain downstream signaling. Nef, a pathogenicity factor of HIV, disrupts early TCR signaling in target T cells. To define the mechanism underlying this Nef-mediated signal disruption, we employed quantitative single-cell microscopy following surface-mediated TCR stimulation that allows for dynamic visualization of distinct signaling complexes as microclusters (MCs). Despite marked inhibition of actin remodeling and cell spreading, the induction of MCs containing TCR-CD3 or ZAP70 was not affected significantly by Nef. However, Nef potently inhibited the subsequent formation of MCs positive for the signaling adaptor Src homology-2 domain-containing leukocyte protein of 76 kDa (SLP-76) to reduce MC density in Nef-expressing and HIV-1-infected T cells. Further analyses suggested that Nef prevents formation of SLP-76 MCs at the level of the upstream adaptor protein, linker of activated T cells (LAT), that couples ZAP70 to SLP-76. Nef did not disrupt pre-existing MCs positive for LAT. However, the presence of the viral protein prevented de novo recruitment of active LAT into MCs due to retargeting of LAT to an intracellular compartment. These modulations in MC formation and composition depended on Nef's ability to simultaneously disrupt both actin remodeling and subcellular localization of TCR-proximal machinery. Nef thus employs a dual mechanism to disturb early TCR signaling by limiting the communication between LAT and SLP-76 and preventing the dynamic formation of SLP-76-signaling MCs.

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Execution of programmed cell death (PCD) in nonmetazoan organisms is morphologically different from apoptotic PCD in animals and lacks a number of key molecular components of apoptotic machinery, including caspases. Yet protozoan, fungal, and plant cells exhibit caspase-like proteolytic activities, which increase in a PCD-dependent manner. This poses a question whether nonmetazoan organisms contain structurally dissimilar proteases that functionally substitute for caspases. Putative ancestors of caspases, metacaspases, are candidates for this role; however, their distinct substrate specificity raises doubts. The identification of a common biological target of caspases and metacaspases and previously unknown functions unrelated to cell death of metacaspases provide new food for thought.

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This paper will examine some of the ways in which processes of denomination
have shaped Northern Irish politics before and after the ‘Belfast’, or ‘Good Friday
Agreement’ of 1998. We concentrate on the formation of the ‘Unionist’ or ‘Loyalist
community’, principally because the flag protests of 2012-2013 have brought the
issue of this community identity to the fore again. The flag is part of a whole
machinery of what we, in this paper, will call ‘denomination’ in Northern Irish
politics and elsewhere. The religious overtones of the term are neither accidental
nor incidental. Acts of denomination posit (assertively, authoritatively) a
collective identity, conceived and constituted ontologically, as an existent entity,
and stake a claim to a whole territory.