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排序方式: 共有434条查询结果,搜索用时 15 毫秒
181.
Fergal O. Rourke Fergal Boyle Anthony Reynolds 《Renewable & Sustainable Energy Reviews》2009,13(8):1975-1984
The energy consumed in Ireland is primarily achieved by the combustion of fossil fuels. Ireland's only indigenous fossil fuel is peat; all other fossil fuels are imported. As fossil fuels continually become more expensive, their use as an energy source also has a negative impact on the environment. Ireland's energy consumption can be separated into three divisions: transportation, electricity generation and heat energy. Ireland however has a vast range of high quality renewable energy resources. Ireland has set a target that 33% of its electricity will be generated from renewable sources by 2020 [I. Government. Delivering a Sustainable Energy Future for Ireland; 2007.]. The use of biomass, wind and ocean energy technologies is expected to play a major part in meeting this target. The use of renewable energy technologies will assist sustainable development as well as being a solution to several energy related environmental problems. This paper presents the current state of renewable energy technologies and potential resources available in Ireland. Considering Ireland's present energy state, a future energy mix is proposed. 相似文献
182.
Lameness is one of the most serious health and welfare problems for dairy cows. This study compared hoof health, limb health and locomotion of dairy cows in three over-winter management systems. Treatments were: (1) an indoor free-stall system (FS), (2) outdoors on an uncovered woodchip pad (UP) and (3) outdoors on a covered woodchip pad (CP). Animals were assigned to treatments at drying off, remained on treatment until parturition, then turned out to pasture. Sole lesions were scored on assignment to treatment, at calving, and 6 weeks and 12 weeks post partum. Locomotion and skin lesions were scored on assignment to treatment, and every 2 weeks until parturition. Post-partum locomotion was scored weekly for 13 weeks. More FS cows were affected by limb lesions than CP cows, and these animals had the worst locomotion scores post calving. There was an effect of inspection, and interactive effect of inspection and treatment on sole lesion scores. UP cows had the highest sole lesion scores 12 weeks post partum probably due to softening of the hooves arising from exposure to moisture while on the woodchip pad. However, post partum, UP cows had better locomotion scores, and CP cows tended to have better scores than cows in FS. Both of these treatments were less likely to have a high tracking-up score than cows in FS. It is possible that cows in this treatment were able to exercise more, owing to the secure underfoot surface and lack of barriers, and this promoted limb flexibility. Although woodchip pads provided benefits for limb health and locomotion, the wood chip surface in both outdoor systems did not offer protective benefits to the hooves relative to housing on concrete. However, the provision of shelter on the pad somewhat overcame the problem of high sole lesion scores in the post-partum period. 相似文献
183.
Svetlana P. Chapoval Mariah Lee Aaron Lemmer Oluwaseyi Ajayi Xiulan Qi Andrew F. Neuwald Achsah D. Keegan 《International journal of molecular sciences》2022,23(6)
Semaphorin 4A (Sema4A) exerts a stabilizing effect on human Treg cells in PBMC and CD4+ T cell cultures by engaging Plexin B1. Sema4A deficient mice display enhanced allergic airway inflammation accompanied by fewer Treg cells, while Sema4D deficient mice displayed reduced inflammation and increased Treg cell numbers even though both Sema4 subfamily members engage Plexin B1. The main objectives of this study were: 1. To compare the in vitro effects of Sema4A and Sema4D proteins on human Treg cells; and 2. To identify function-determining residues in Sema4A critical for binding to Plexin B1 based on Sema4D homology modeling. We report here that Sema4A and Sema4D display opposite effects on human Treg cells in in vitro PBMC cultures; Sema4D inhibited the CD4+CD25+Foxp3+ cell numbers and CD25/Foxp3 expression. Sema4A and Sema4D competitively bind to Plexin B1 in vitro and hence may be doing so in vivo as well. Bayesian Partitioning with Pattern Selection (BPPS) partitioned 4505 Sema domains from diverse organisms into subgroups based on distinguishing sequence patterns that are likely responsible for functional differences. BPPS groups Sema3 and Sema4 into one family and further separates Sema4A and Sema4D into distinct subfamilies. Residues distinctive of the Sema3,4 family and of Sema4A (and by homology of Sema4D) tend to cluster around the Plexin B1 binding site. This suggests that the residues both common to and distinctive of Sema4A and Sema4D may mediate binding to Plexin B1, with subfamily residues mediating functional specificity. We mutated the Sema4A-specific residues M198 and F223 to alanine; notably, F223 in Sema4A corresponds to alanine in Sema4D. Mutant proteins were assayed for Plexin B1-binding and Treg stimulation activities. The F223A mutant was unable to stimulate Treg stability in in vitro PBMC cultures despite binding Plexin B1 with an affinity similar to the WT protein. This research is a first step in generating potent mutant Sema4A molecules with stimulatory function for Treg cells with a view to designing immunotherapeutics for asthma. 相似文献
184.
SE Grill WF Rosenberger K Boyle M Cannon M Hallett 《Canadian Metallurgical Quarterly》1998,9(18):4001-4005
A psychophysical method was used to estimate the timing of perception of kinesthetic stimuli with different velocities in normal volunteers. A 1 ms auditory click occurred randomly before or after an imposed flexion movement at either 20, 40 or 60 deg/s of the metacarpophalangeal joint. Subjects reported whether the click was perceived before or after the movement onset (experiment 1) or perception of movement velocity (experiment 2). The time at which there was a 50% chance that subjects reported movement or velocity perception after the click was taken as an estimate of the time subjects perceived the stimuli. The difference in time of perceived movement velocity discrimination and movement onset was only significant when the velocity was 20 deg/s (52 ms). This suggests that movement onset and identification of the velocity of the faster movements are perceived nearly simultaneously. 相似文献
185.
186.
187.
Mandibular distraction was performed on 14 children, between September 1991 and December 1997. Their average age was 6.9 years, ranging from 1.5 to 13.5 years. All patients had severe hypoplastic mandibles with retromandibulism. Seven of the children (50%) had respiratory distress due to obstruction of the upper airway before distraction. This resolved in every case. Five patients underwent unilateral and nine bilateral distraction. A total of 23 distractors were used, 15 were applied extraorally and 8 endorally. The average latency time after operation was 2.8 days, but for the past 2 years, distraction was started beginning with the operation. The distraction was increased twice daily for an average of 5.5 weeks, by 0.4 or 0.5 mm each time, depending on the distractor. Computed tomography and ultrasound were used to follow the ossification process in the distraction gap and to measure the lengthening achieved. Subsequent retention time averaged 2.4 weeks. The mandibles were elongated by up to 18 mm (average 9.3 mm) and the respiratory distress symptoms resolved in all patients. Several minor complications which are reported occurred. Six patients were followed up for periods between 3 and 7 years. During this time further growth of the distracted mandibles was recorded. 相似文献
188.
SL Branton BD Lott JD May WR Maslin CR Boyle GT Pharr 《Canadian Metallurgical Quarterly》1997,41(4):832-837
In each of two trials, 160 commercial pullets were separated into four treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation; 40 other pullets received F strain Mycoplasma gallisepticum (FMG); an additional 40 pullets received Mycoplasma synoviae (MS); and the final 40 pullets were inoculated with both FMG and MS (dual). Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded in each trial through an entire laying cycle. No significant difference was observed among the treatments for hen-day egg production, egg weight, eggshell strength, or Haugh unit scores. Significant differences were observed for pimpling incidence among controls (1.63%), Mycoplasma gallisepticum (MG)-infected (2.09%), and dual-infected hens (2.41%). A significant difference in blood/meat spot incidence was observed between MG-infected hens (0.27%) and dual-infected hens (0.45%). Histopathologic examination of the ovary and all segments of the oviduct revealed no significant differences among the treatments. These results suggest that the majority of the hen reproductive tract functions similarly in FMG-vaccinated, MS-infected, or dual-infected hens as compared with Mycoplasma-clean hens. 相似文献
189.
190.
S Kugathasan J Willis BB Dahms MA O''Riordan V Hupertz DG Binion JT Boyle C Fiocchi 《Canadian Metallurgical Quarterly》1998,133(5):675-681
1. The basic etiology of Alzheimer's disease remains unknown, although four genes have so far been involved: beta-amyloid precursor protein, presenilin-1, presenilin-2 and apolipoprotein E genes. 2. The largest familial Alzheimer's disease (FAD) kindred so far reported belong to a point mutation in codon 280 that results in a glutamic acid-to-alanine substitution in presenilin-1 characterized in Antioquia, Colombia. 3. A hypothetical unified molecular mechanism model of cell death in FAD mediated by presenilin-1, beta-amyloid, and oxidative stress is proposed as an attempt to explain the mechanisms of neuronal loss in this neurodegenerative disorder. 相似文献