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1.
DE Forsythe 《Canadian Metallurgical Quarterly》1998,86(3):402-409
Although several liver diseases of childhood, particularly biliary atresia (BA) and cystic fibrosis (CF) liver disease (CFLD) are characterized by hepatic fibrosis, the pathogenesis of this process is incompletely understood. The cytokine transforming growth factor-beta1 (TGF-beta1) has been implicated in hepatic fibrosis in experimental animals, in which both the hepatic expression and plasma concentration of this cytokine are increased. The objective of our study was to determine whether there are similar alterations of TGF-beta1 in patients with hepatic fibrosis secondary to either BA and/or CFLD. The study design was as follows. In study 1, plasma TGF-beta1 was assessed by ELISA in 9 children with BA undergoing liver transplantation, 11 patients with CFLD, and appropriate control subjects. In study 2, hepatic expression of TGF-beta1 protein (assessed immunohistochemically) and hepatic fibrosis were scored semiquantitatively, on a 1-3 scale, by blinded investigators, in archival liver biopsy specimens from 10 children with BA, 10 with CFLD, and from 10 older children with normal hepatic histology, as well as in 4 patients with liver diseases of various etiologies. Simultaneous plasma and liver TGF-beta1 studies were performed in 8 patients with liver disease. Results were as follows. Plasma TGF-beta1 values were inversely correlated with age in healthy subjects (r=-0.54, p < 0.0001). The plasma TGF-beta1 protein of children with BA was decreased (13+/-2 ng/mL) compared with values for healthy children (42+/-6 ng/mL, n=10, p < 0.005). Similarly, the plasma TGF-beta1 concentration in patients with CFLD was also decreased compared with values for children with CF and normal serum liver profiles (n=14) (2+/-1 ng/mL versus 12+/-1, p < 0.05). However, the plasma TGF-beta1 concentration was increased in two patients with other types of liver disease. The hepatic expression of TGF-beta1 was increased in the presence of hepatic fibrosis in all types of liver diseases studied. Forty-six percent of patients had both marked hepatic fibrosis and marked TGF-beta1 labeling; 86% of samples without fibrosis showed no TGF-beta1 labeling, p=0.007. In conclusion, these studies have established the association of hepatic TGF-beta1 protein and hepatic fibrosis in several common liver diseases of childhood. Our data also suggest that, in children, plasma TGF-beta1 does not appear to be a useful marker of hepatic expression of this cytokine. 相似文献
2.
Current regulation plays an important part in the protection of solid-state drives operating from stiff voltage sources. Certain types of pulsewidth modulated (PWM) inverters, however, are not directly suited for peak or average output current regulation with induction motor loading. It is established in the paper that the typical output voltage response times of defined voltage waveform PWM inverters are 1) too high for peak output current regulation, and 2) too low for average output current regulation?i.e., for stable current regulation, the control system must limit the rate of inverter output voltage reduction. Inverter voltage control requirements and inverter deratings necessary to implement average output current regulation are presented. Experimental results from a 15-hp bread-board are included. 相似文献
3.
S.B. Gilliam S.M. Gidcumb D.G. Forsythe J.D. Hunn G.P. Lamaze 《Journal of Nuclear Materials》2005,347(3):289-297
The first wall of an inertial fusion energy reactor may suffer from surface blistering and exfoliation due to helium ion irradiation and extreme temperatures. Tungsten is a candidate for the first wall material. A study of helium retention and surface blistering with regard to helium dose, temperature, pulsed implantation, and tungsten microstructure was conducted to better understand what may occur at the first wall of the reactor. Single crystal and polycrystalline tungsten samples were implanted with 1.3 MeV 3He in doses ranging from 1019 m−2 to 1022 m−2. Implanted samples were analyzed by 3He(d,p)4He nuclear reaction analysis and 3He(n,p)T neutron depth profiling techniques. Surface blistering was observed for doses greater than 1021 He/m2. For He fluences of 5 × 1020 He/m2, similar retention levels in both microstructures resulted without blistering. Implantation and flash heating in cycles indicated that helium retention was mitigated with decreasing He dose per cycle. 相似文献
4.
Perry Forsythe 《Construction Management & Economics》2013,31(12):683-699
Measuring construction productivity in an accurate, repeatable and reliable way represents a significant problem at a building project level of enquiry. The research develops a measurement framework that balances simplified data gathering against explanatory ability. It aims to assist analytically driven process improvement. Debate and discourse are used to draw upon the extant literature in creating a logic-based flow of ideas to develop the framework. Targeted use of empirical cost and site process data from case studies are presented to punctuate the discourse. The derived approach advocates multifactor measurement inclusive of labour and temporary production infrastructure inputs, set against Gross Floor Area outputs. Emphasis is placed on separately measuring homogenous and heterogeneous parts of work processes. A reductionist approach is used to operationalize measurement where projects are categorized according to fitness-for-purpose criteria and links made between systems, activities and tasks. Emphasizing measurement of homogenous parts of the work is new to the literature. It enables delineated measurement between work involving mass economies of scale (homogenous work), versus customized work (heterogeneous work). The approach enables improved benchmarking, diagnostic and predicative options. A course of ongoing research is provided to assist ongoing development and implementation. 相似文献
5.
In 2010, the Australian residential construction sector contributed about 28% of the value of all construction and was responsible for 8% of the total energy consumption. Residential construction will continue to increase to cope with the demand due to population growth. Owing to land scarcity, construction on sloping sites has become a common construction method for residential development in Australia. This method has economic benefits but poses environmental issues as it damages topsoil, disturbs natural drainage and groundwater pathways and imposes additional stress on soil under fill. The life cycle energy consumption of the construction process is examined in relation to residential projects on sloping sites on a range of slopes and soil types in New South Wales, Australia. Forty-one detached dwellings were selected and a service life of 60 years assumed for the study. The research findings reveal that the slope for each type of soil has a positive correlation with life cycle energy consumption. As part of the onsite construction process, the results also show that the energy consumption of construction on sloping sites plays a significant factor in the life cycle energy analysis of a building. 相似文献
6.
Lipopolysaccharide (LPS) is a heat stable endotoxin that persists during the processing of powdered infant formula milk (IFM). Upon ingestion it may increase the permeability of the neonatal intestinal epithelium and consequently bacterial translocation from the gut. To determine the level of endotoxin present in IFM, 75 samples were collected from seven countries (representing 31 brands) and analysed for endotoxin using the kinetic colorimetric Limulus amoebocyte lysate (LAL) assay. The endotoxin levels ranged from 40 to 5.5 x 10(4) endotoxin units (EU) per gram and did not correlate with the number of viable bacteria. The neonate rat model was used to address the risk of endotoxin-induced bacterial translocation from the gut. Purified Escherichia coli LPS was administered to rat pups followed by inoculation with Enterobacter sakazakii ATCC 12868. Bacteria were isolated from the mesentery, spleen, blood and cerebral spinal fluid (CSF) of endotoxin-treated rats due to enhanced gut and blood brain barrier penetration. Histological analysis of the colon showed marked distension of the mucosal and muscular layers. It is plausible that the risk of neonatal bacteraemia and endotoxemia, especially in neonates with immature innate immune systems, may be raised due to ingestion of IFM with high endotoxin levels. 相似文献
7.
8.
Milliken Garrett W.; Forsythe Chris; Ward Jeanette P. 《Canadian Metallurgical Quarterly》1989,103(3):262
Evaluated a free-ranging matriline of 13 ring-tailed lemurs (Lemur catta) from videotaped records for lateralized hand use with 2 tasks and 4 measures: food reaching, feeding posture, duration of food holding, and manipulation of food between mouth and hand while eating. Binomial z scores determined 7 lemurs to be left preferent in reaching, 3 right, and 3 ambipreferent. Ideographic analyses suggested possible sex-linked and early experience twin effects. When compared to right and ambipreferent lemurs, left reach preferent lemurs used the left hand more but bimanuals grasped less in food holding and also engaged in less hand-mouth food manipulation. The tendency to manipulate food was not correlated with bimanual holding but was inversely related to left hand holding and directly related to right hand holding. These patterns are discussed as possible precursors of human bimanual manipulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
SA Mousa M Forsythe J Bozarth A Youssef J Wityak R Olson T Sielecki 《Canadian Metallurgical Quarterly》1998,32(5):736-744
XV454 demonstrated high potency (IC50 = 14-25 nM) in inhibiting human platelet aggregation induced by adenosine diphosphate (ADP, 10 microM), thrombin receptor agonist peptide (TRAP) (10 microM), or collagen (20 microg/ml). XV454 exhibited a high degree of selectivity for platelet alpha(IIb)beta3 in comparison with c7E3, which is a nonspecific antagonist for both alpha(IIb)beta3 and alpha(v)beta3. Both XV454 and c7E3 bind with high affinity to either activated (A) or unactivated (U) human, baboon, or canine platelets. XV454 binds with a relatively higher affinity [Kd = 0.5 nM (A), 0.6 nM (U)] as compared with c7E3 [Kd = 9.1 nM (A), 9.2 (U) nM]. XV454 demonstrated a tight association with human, baboon, and, to a lesser extent, with canine platelets (t(1/2) of dissociation = 110 +/- 6, 80 +/- 10, and 23 +/- 2 min, respectively). Both c7E3 and XV454 associate tightly with a slower dissociation rate with unactivated human platelets: t(1/2) of 42 and 116 min, respectively. In non-human primates, oral (0.1 mg/kg, p.o.) and intravenous (0.05 mg/kg, i.v. bolus administration of XV454 methyl ester pro-drug resulted a long-lasting maximal antiplatelet efficacy for < or = 72 h with significant but reversible prolongation of bleeding time and without effects on platelet count, clinical chemistry, or hemodynamic profile. In conclusion, XV454 represents a potent antiplatelet agent in inhibiting platelet aggregation along with a high affinity and relatively slow dissociation rate from human platelet GPIIb/IIIa receptors that allow a long-lasting antiplatelet efficacy after single i.v. or oral administration. 相似文献
10.
The temperature and frequency dependence of the dynamic mechanical properties in the glass transition was studied for a series of partially cured thermally reactive networks (low temperature cured epoxy and a dimethacrylate photocured with a conventional initiator) and more thermally stable networks (high temperature cured epoxy and two dimethacrylates photocured with a photoiniter1). The viscoelastic behavior in the transition region of the former networks changed during the experiment due to additional cure, whereas the thermally stable networks enabled the study of the effect of conversion on the transition region. The glass transition temperatures showed 1 : 1 relationships with the isothermal curing temperatures and were correlated with the degree of conversion. The breadth of the glass transition, as determined from the real and loss moduli, tan δ, and the loss compliance in the temperature and frequency domains, was found to be greater for the dimethacrylate networks than for the epoxy networks. The breadth of the transition for the dimethacrylates was not significantly dependent on the degree of cure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1348–1359, 2004 相似文献