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51.
Imaging through scattering materials is an important research area that is generally limited to medical diagnostic applications. Published techniques typically use a method of time- or coherence-gating of ballistic photons that separates these early photons in order to acquire an image without the large background created by the later-arriving diffuse light. Because of the limited number of ballistic photons and the typically low signal-to-noise ratios of these schemes, a large number of averages or scans is necessary. If the desired image is changing rapidly, however, single images of this transient are required. We have therefore evaluated a two-dimensional, single-shot method that can be used for imaging rapid transients in scattering environments. 相似文献
52.
Indirect cytotoxicity evaluation of pseudowollastonite 总被引:1,自引:0,他引:1
Dufrane D Delloye C McKay IJ De Aza PN De Aza S Schneider YJ Anseau M 《Journal of materials science. Materials in medicine》2003,14(1):33-38
This study aimed to evaluate the cytotoxicity of substances leached by pseudowollastonite (CaSiO3). It has been previously shown that calcium (Ca2+) and silicate (SiO3
–) ions are released from pseudowollastonite into biological solutions. Both of these ions are known to influence the biological metabolism of osteoblastic cells essential in the mineralization process and bone-bonding mechanism. The indirect toxicity evaluation was performed by extraction method, according to International Standard Organization (ISO). Pseudowollastonite pellets obtained by solid-state reaction were incubated, in culture medium, during 24, 48, 72 or 168 h at different concentrations (5, 10, 15, 50, 100, 200 mg/ml). The cytotoxicity of each extract in presence of human osteoblastic cell line (SaOS-2) was quantitatively assessed by measuring the viability (succinate dehydrogenase activity, MTT), the membrane integrity (the uptake of the neutral red by viable cells, NR) as well as the cell necrosis by measuring the lactate dehydrogenase (LDH) released in the culture medium. No significant alteration of membrane integrity or cell suffering was detectable. However, increased cell metabolism was observed for cells exposed to pseudowollastonite extract with longest extraction time (168 h). In conclusion, mineral elements leached by pseudowollastonite do not significantly affect the metabolism of osteoblastic cells. 相似文献
53.
McKay Kevin M.; Hill Melanie S.; Freedman Suzanne R.; Enright Robert D. 《Canadian Metallurgical Quarterly》2007,44(1):14
In recent years Enright and Fitzgibbon's (2000) process model of forgiveness therapy has received substantial theoretical and empirical attention. However, both the process model of forgiveness therapy and the social-cognitive developmental model on which it is based have received criticism from feminist theorists. The current paper considers feminist criticisms of forgiveness therapy and uses a feminist lens to identify potential areas for growth. Specifically, Worell and Remer's (2003) model of synthesizing feminist ideals into existing theory was consulted, areas of bias within the forgiveness model of psychotherapy were identified, and strategies for restructuring areas of potential bias were introduced. Further, the authors consider unique aspects of forgiveness therapy that can potentially strengthen existing models of feminist therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
54.
RA McKay LJ Miraglia LL Cummins SR Owens H Sasmor NM Dean 《Canadian Metallurgical Quarterly》1999,274(3):1715-1722
The use of antisense oligonucleotides to inhibit the expression of targeted mRNA sequences is becoming increasingly commonplace. Although effective, the most widely used oligonucleotide modification (phosphorothioate) has some limitations. In previous studies we have described a 20-mer phosphorothioate oligodeoxynucleotide inhibitor of human protein kinase C-alpha expression. In an effort to identify improved antisense inhibitors of protein kinase C expression, a series of 2' modifications have been incorporated into the protein kinase C-alpha targeting oligonucleotide, and the effects on oligonucleotide biophysical characteristics and pharmacology evaluated. The incorporation of 2'-O-(2-methoxy)ethyl chemistry resulted in a number of significant improvements in oligonucleotide characteristics. These include an increase in hybridization affinity toward a complementary RNA (1.5 degrees C per modification) and an increase in resistance toward both 3'-exonuclease and intracellular nucleases. These improvements result in a substantial increase in oligonucleotide potency (>20-fold after 72 h). The most active compound identified was used to examine the role played by protein kinase C-alpha in mediating the phorbol ester-induced changes in c-fos, c-jun, and junB expression in A549 lung epithelial cells. Depletion of protein kinase C-alpha protein expression by this oligonucleotide lead to a reduction in c-jun expression but not c-fos or junB. These results demonstrate that 2'-O-(2-methoxy)ethyl-modified antisense oligonucleotides are 1) effective inhibitors of protein kinase C-alpha expression, and 2) represent a class of antisense oligonucleotide which are much more effective inhibitors of gene expression than the widely used phosphorothioate antisense oligodeoxynucleotides. 相似文献
55.
A wide range of experimental studies are reported for the adsorption of phenol and p-chlorophenol onto activated carbon—Type Filtrasorb 400—in an agitated batch adsorber. A model has been used to determine the external mass transfer coefficient for the systems and the effect of several experimental variables have been investigated: these include agitation, initial pollutant concentration, carbon mass, carbon particle size and solution temperature. The mass transfer coefficient has been correlated in terms of the dimensionless Sh/Sc0.33 against each variable. The Sherwood number, Sh = kfR/Dmol, relates the external mass transfer coefficient kf to particle radius, R, and molecular diffusivity, Dmol. The Schmidt number, Sc, is the ratio of kinematic viscosity, v, to molecular diffusivity. A few results are also reported for the adsorption of sodium dodecyl sulphate and mercuric ions onto activated carbon. 相似文献
56.
Schedulers' decisions in real factories deal with perceived risks and impacts. They proactively anticipate and reactively mitigate risky events by altering what would be considered a normal schedule to minimize associated impacts. These risk mitigation concepts are called aversion dynamics (AD). Aversion dynamics describes the aversion that jobs exhibit to impacts resulting from risky events in dynamic and unstable production environments. The aversion manifests itself in either advancing or delaying the work to avoid the risky period. This paper extends the first AD heuristic, Averse-1, to capture additional real-world dynamics and to make the heuristic predictive (proactive) as to when the perceived risky event may happen. In particular, predictive and stochastic elements are incorporated within a dynamic job arrival framework to create an extended heuristic called Averse-2. 相似文献
57.
TL Holyoake MG Freshney L McNair AN Parker PJ McKay WP Steward E Fitzsimons GJ Graham IB Pragnell 《Canadian Metallurgical Quarterly》1996,87(11):4589-4595
The characterization of many cytokines involved in the control of hematopoiesis has led to intense investigation into their potential use in ex vivo culture to expand progenitor numbers. We have established the optimum ex vivo culture conditions that allow substantial amplification of transient engrafting murine stem cells and which, simultaneously, augment the ability to sustain serial bone marrow transplantation (BMT). Short-term incubation of unfractionated BM cells in liquid culture with stem cell factor (SCF) and interleukin-11 (IL-11) produced a 50-fold amplification of clonogenic multipotential progenitors (CFU-A). Following such ex vivo expansion, substantially fewer cells were required to rescue lethally irradiated mice. When transplanted in cell doses above threshold for engraftment, BM cells expanded ex vivo resulted in significantly more rapid hematopoietic recovery. In a serial transplantation model, unmanipulated BM was only able to consistently sustain secondary BMT recipients, but BM expanded ex vivo has sustained quaternary BMT recipients that remain alive and well more than 140 days after 4th degree BMT. These results show augmentation of both short-term recovery posttransplant and the ability to serially transplant marrow by preincubation in culture with SCF and IL-11. 相似文献
58.
PF McKay N Imami M Johns DA Taylor-Fishwick LM Sedibane NF Totty JJ Hsuan DB Palmer AJ George BM Foxwell MA Ritter 《Canadian Metallurgical Quarterly》1998,28(12):4071-4083
The human gp200-MR6 molecule has previously been shown to have either an antagonistic or agonistic effect on IL-4 function, demonstrated by inhibition of IL-4-induced proliferation of T cells or mimicking of IL-4-induced maturation of epithelium, respectively. We now show that gp200-MR6 ligation can also mimic IL-4 and have an anti-proliferative pro-maturational influence within the immune system, causing up-regulation of co-stimulatory molecules on B lymphocytes. Biochemical analysis and cDNA cloning reveal that gp200-MR6 belongs to the human macrophage mannose receptor family of multidomain molecules. It comprises 1722 amino acids in toto (mature protein, 1695 amino acids; signal sequence, 27 amino acids) organized into 12 external domains (an N-terminal cysteine-rich domain, a fibronectin type II domain and 10 C-type carbohydrate recognition domains), a transmembrane region and a small cytoplasmic C terminus (31 amino acids) containing a single tyrosine residue (Y1679), but no obvious kinase domain. Strong amino acid sequence identity (77%) suggests that gp200-MR6 is the human homologue of the murine DEC-205, indicating that this molecule has much wider functional activity than its classical endocytic role. We also show that the gp200-MR6 molecule is closely associated with tyrosine kinase activity; the link between gp200-MR6 and the IL-4 receptor may therefore be via intracellular signaling pathways, with multifunctionality residing in its extracellular multidomain structure. 相似文献
59.
60.
This paper describes a case study of a neighborhood pub in British Columbia, Canada. This case study is an examination of three common pub occupations-bartending, waitressing and cooking (n = 17). The aims of this study are to determine the biomechanical loads of job tasks identified as physically demanding for the three occupations analyzed, to assess the potential risk of musculoskeletal injury in these job tasks, and to recommend injury prevention measures. Risk of musculoskeletal injury was assessed with four validated methods (RULA, NIOSH lifting equation, Shoaf pulling model, 3D Static Strength prediction program). Tasks commonly and frequently performed were observed to pose some risk to the working populations and require investigation and changes soon as indicated by the upper extremity and low-back assessment procedures used. Mean combined compression at the lumbrosacral disc in common tasks have been demonstrated to exceed the action limit described by NIOSH. Ligament strain was observed to reach as high as 18% at the lumbosacral joint. 相似文献