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51.
Michael Ferrara Michael Stephens Leslie Marchut Chris Yang Ventony Fryar Preston Scott 《Microelectronics Reliability》2012,52(1):9-15
With the increasing complexity of the power amplifier (PA) module architecture, the probability of a thermally induced stress related failure mechanism increases. To help evaluate the increase in module complexity, a more sophisticated in situ monitored thermal cycle reliability test is available. The module is monitored in real time using a resistance daisy chain methodology designed to provide coverage using resistance feedback throughout the entire hierarchy of the module and carrier board interface. Monitored temperature cycling allows for real time failure feedback and enhanced failure signature information. Further, the testing technique has proven to be a valuable method for capturing the early stages of a module mechanical failure at the temperature extremes. Moreover, statistical evaluation of the failure data (Weibull analysis) is improved and better accuracy of the failures in time (FIT) rate can be determined. 相似文献
52.
Aaron J. Krych Florian Wanivenhaus Kenneth W. Ng Stephen Doty Russell F. Warren Suzanne A. Maher 《Journal of materials science. Materials in medicine》2013,24(10):2429-2437
Articular cartilage defects are a significant source of pain, have limited ability to heal, and can lead to the development of osteoarthritis. However, a surgical solution is not available. To tackle this clinical problem, non-degradable implants capable of carrying mechanical load immediately after implantation and for the duration of implantation, while integrating with the host tissue, may be viable option. But integration between articular cartilage and non-degradable implants is not well studied. Our objective was to assess the in vivo performance of a novel macroporous, nondegradable, polyvinyl alcohol construct. We hypothesized that matrix generation within the implant would be enhanced with partial digestion of the edges of articular cartilage. Our hypothesis was tested by randomizing an osteochondral defect created in the trochlea of 14 New Zealand white rabbits to treatment with: (i) collagenase or (ii) saline, prior to insertion of the implant. At 1 and 3-month post-operatively, the gross morphology and histologic appearance of the implants and the surrounding tissue were assessed. At 3 months, the mechanical properties of the implant were also quantified. Overall, the hydrogel implants performed favorably; at all time-points and in all groups the implants remained well fixed, did not cause inflammation or synovitis, and did not cause extensive damage to the opposing articular cartilage. Regardless of treatment with saline or collagenase, at 1 month post-operatively implants from both groups had a contiguous interface with adjacent cartilage and were populated with chondrocyte-like cells. At 3 months fibrous encapsulation of all implants was evident, there was no difference between area of aggrecan staining in the collagenase versus saline groups, and implant modulus was similar in both groups; leading us to reject our hypothesis. In summary, a porous PVA osteochondral implant remained well fixed in a short term in vivo osteochondral defect model; however, matrix generation within the implant was not enhanced with partial digestion of adjacent articular cartilage. 相似文献
53.
Outsourced information systems development (OISD) projects are challenging endeavors, and the literature suggests differences between the parties involved as critical hinderers of such projects. Using institutional theory as a foundational theory, we propose a process explanation of the effects of differences between parties in OISD projects. Our explanation relies on the interaction of four components: (1) the IS development and project management institutional profiles of the parties involved; (2) the institutional distance between practices within these profiles; (3) instances of conflicting institutional demands when institutional distance becomes salient; and (4) the repertoire of institutional strategic responses available to parties to address those instances. We suggest that the constitutive elements of institutional distance and the degree to which parties envision their collaboration beyond the project at hand contribute to explaining the enactment of strategic responses. Accounting for the fact that practices, as well as the institutional logics that drive their enactment, may differ between parties, we make a theoretical contribution to the literature on OISD by building a fine-grained explanation of the effects of differences between parties in OISD projects. 相似文献
54.
Understanding the bioaerosol dynamics of droplets and droplet nuclei emitted during respiratory activities is important for understanding how infectious diseases are transmitted and potentially controlled. To this end, we conducted experiments to quantify the size‐resolved dynamics of indoor bioaerosol transport and control in an unoccupied apartment unit operating under four different HVAC particle filtration conditions. Two model organisms (Escherichia coli K12 and bacteriophage T4) were aerosolized under alternating low and high flow rates to roughly represent constant breathing and periodic coughing. Size‐resolved aerosol sampling and settle plate swabbing were conducted in multiple locations. Samples were analyzed by DNA extraction and quantitative polymerase chain reaction (qPCR). DNA from both organisms was detected during all test conditions in all air samples up to 7 m away from the source, but decreased in magnitude with the distance from the source. A greater fraction of T4 DNA was recovered from the aerosol size fractions smaller than 1 μm than E. coli K12 at all air sampling locations. Higher efficiency HVAC filtration also reduced the amount of DNA recovered in air samples and on settle plates located 3‐7 m from the source. 相似文献
55.
Wendy S. Smith David A. Johnston Harrison J. Wensley Suzanne E. Holmes Sopsamorn U. Flavell David J. Flavell 《International journal of molecular sciences》2020,21(22)
Cholesterol seems to play a central role in the augmentation of saporin-based immunotoxin (IT) cytotoxicity by triterpenoid saponins. Endolysosomal escape has been proposed as one mechanism for the saponin-mediated enhancement of targeted toxins. We investigated the effects of lipid depletion followed by repletion on Saponinum album (SA)-induced endolysosomal escape of Alexa Fluor labelled saporin and the saporin-based immunotoxin OKT10-SAP, directed against CD38, in Daudi lymphoma cells. Lipid deprived cells showed reduced SA-induced endolysosomal escape at two concentrations of SA, as determined by a flow cytometric method. The repletion of membrane cholesterol by low density lipoprotein (LDL) restored SA-induced endolysosomal escape at a concentration of 5 µg/mL SA but not at 1 µg/mL SA. When LDL was used to restore the cholesterol levels in lipid deprived cells, the SA augmentation of OKT10-SAP cytotoxicity was partially restored at 1 µg/mL SA and fully restored at 5 µg/mL SA. These results suggest that different mechanisms of action might be involved for the two different concentrations of SA and that endosomal escape may not be the main mechanism for the augmentation of saporin IT cytotoxicity by SA at the sub-lytic concentration of 1 µg/mL SA. 相似文献
56.
Joelle Ilunga Kongolo Laura Suzanne Da Silva Obiro Cuthbert Wokadala Belinda Du Plessis Johan Husselman Mduduzi E. K. Ngcobo Naushad M. Emmambux Mieke Daneel 《Sensing and Instrumentation for Food Quality and Safety》2017,11(3):1056-1064
Unripe banana flour is a potential commercial ingredient in various food products for increased resistant starch and reduced gluten contents. In the present study, the pasting (rapid visco-analysis), gel texture (penetration test), thermal (differential scanning calorimetry), colour (tri-stimulus colour indices) and the resistant starch properties of unripe banana flour produced from different dessert banana varieties (n?=?10) cultivated in South Africa, were analysed and juxtaposed to wheat and maize flour. The functional properties varied significantly (p?≤?0.05) between banana varieties, and from wheat and maize flours, to various extents. Selected functional property ranges of unripe banana, wheat and maize flours, respectively included; flour colour index (63.16–76.42, 77.34 and 80.96), paste viscosity (405.5–556.6, 124.7 and 115.6 RVU), gelatinization temperature (64.67–71.21, 71.11 and 69.95?°C), gel firmness (7.24–11.44?×?10??2 N, 3.49?×?10??2 N and 6.56?×?10??2 N) and resistant starch content (19.9–47.4, 2.8 and 2.2% w/w). Multivariate analysis (principle component analysis) showed that the unripe banana flours from different varieties were distinguished from each other based on the pasting temperature. The unripe banana flours were distinguished from both wheat and maize flour based on breakdown and peak paste viscosities. The breakdown viscosity was the most positively related measure to the resistant starch content with a linear regression R-squared value of 0.898, indicating a significant role played by granule structure in resistance to enzymatic hydrolysis. The present research demonstrates that selection of appropriate dessert banana variety is important when replacing staple flours (wheat and maize) with unripe dessert banana flour as a functional ingredient. 相似文献
57.
Umberto C. Gatti Susan M. Bogus Suzanne Schneider 《Construction Management & Economics》2014,32(6):548-564
The monitoring of construction workforce physical strain can be a valuable management strategy in improving workforce productivity, safety, health, and quality of work. Nevertheless, clear relationships between workforce performance and physical strain have yet to be established. An exploratory investigation of the relationship between task level productivity and physical strain was conducted. Nine participants individually performed a four-hour simulated construction task while a wearable physiological status monitor continuously assessed their physiological condition. Heart rate, relative heart rate, and breathing rate were utilized as predictors of physical strain, and task level–single factor productivity was used as an index of productivity. Numerous regression models were generated using the collected data. This investigation initially unsuccessfully attempted to establish a relationship between physiological condition and productivity at the individual worker level. However, an analysis of the regression models showed that there is a relationship between productivity and either heart rate or relative heart rate at the group level, and that this relationship is parabolic. Breathing rate was proved to not be a significant predictor of productivity. Research results significantly improve understanding of the relationship between work physiology and task productivity. Researchers and practitioners may use the tested monitoring devices, analysis methods, and results to design further applied studies and to improve workforce productivity. 相似文献
58.
The Naive Bayes approximation (NBA) and associated classifier are widely used and offer robust performance across a large spectrum of problem domains. As it depends on a very strong assumption—independence among features—this has been somewhat puzzling. Various hypotheses have been put forward to explain its success and many generalizations have been proposed. In this paper we propose a set of “local” error measures—associated with the likelihood functions for subsets of attributes and for each class—and show explicitly how these local errors combine to give a “global” error associated to the full attribute set. By so doing we formulate a framework within which the phenomenon of error cancelation, or augmentation, can be quantified and its impact on classifier performance estimated and predicted a priori. These diagnostics allow us to develop a deeper and more quantitative understanding of why the NBA is so robust and under what circumstances one expects it to break down. We show how these diagnostics can be used to select which features to combine and use them in a simple generalization of the NBA, applying the resulting classifier to a set of real world data sets. 相似文献
59.
Chiarello Christine; Welcome Suzanne E.; Halderman Laura K.; Towler Stephen; Julagay Janelle; Otto Ronald; Leonard Christiana M. 《Canadian Metallurgical Quarterly》2009,23(2):210
The authors report findings of a large-scale, multitask investigation of sex differences in both structural asymmetries and lateralization of word reading. Two hundred participants were tested in eight divided visual field lexical tasks, and each received a structural magnetic resonance imaging scan. The authors examined whether there was evidence for sex differences in overall measures of neuroanatomical and behavioral lateralization, in specific language tasks and brain regions, and in variation in asymmetry within and across tasks and brain regions. There was very little evidence for sex differences on any behavioral measure. The few indications of sex differences in the current report accounted for 2% or less of the individual variation in asymmetry and could not be replicated in independent subsamples. No sex differences were observed in the asymmetry of structures in Broca's and Wernicke's areas such as pars triangularis, pars opercularis, the planum temporale, planum parietale, or Heschl's gyrus. There were also no sex differences in the variability of neuroanatomical asymmetries within or between brain regions. However, a significant relationship between planum temporale and behavioral asymmetry was restricted to men. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
John Stephens 《Urban Policy and Research》2013,31(1):87-99
Karalee Rock is a location deep in the Western Australian bush between Southern Cross and Coolgardie. It is a natural landscape that has been scarred by water engineering and industrial use and is a well used local recreation area and tourist destination. Karalee offers a contained setting in which to discuss the role of identity in the processes of place formation and the importance of recognising and understanding places in the redevelopment of urban environments. 相似文献