1,389 research outputs found
The development of low temperature curing adhesives
An approach for the development of a practical low temperature (293 K-311 K/68 F-100 F) curing adhesive system based on a family of amide/ester resins was studied and demonstrated. The work was conducted on resin optimization and adhesive compounding studies. An improved preparative method was demonstrated which involved the reaction of an amine-alcohol precursor, in a DMF solution with acid chloride. Experimental studies indicated that an adhesive formulation containing aluminum powder provided the best performance when used in conjunction with a commercial primer
Functional molecular mass of rat hepatic lipase in liver, adrenal gland and ovary is different
Lipoprotein lipase (LPL) is functionally active only as a dimer. It is
also generally assumed that the highly homologous hepatic lipase functions
as a dimer, but no clear evidence has been presented. A hepatic
lipase-like activity, also indicated as L-type lipase, is present in
adrenal and ovary tissues. This enzyme is thought to originate from the
liver and to be identical to hepatic lipase. We determined the functional
molecular mass of hepatic lipase in rat liver, adrenal gland and ovary by
radiation inactivation, a method for determining the functional size of a
protein without the need of prior purification. Samples were exposed to
ionizing radiation at -135 degrees C. Hepatic lipase activity in liver
homogenate showed a single exponential decay. The functional molecular
mass was calculated to be 63 +/- 10 kDa. Hepatic lipase activity in
adrenal homogenate was found to have a functional molecular mass of 117
+/- 16 kDa. The functional molecular masses of the lipases partially
purified from rat liver perfusate, adrenal homogenate or ovarian
homogenate showed the same pattern, a target mass for the liver enzyme of
56 +/- 6 kDa and a target mass of 117 +/- 14 kDa for the enzyme from
adrenal gland or ovary. In Western blot analysis the mass of the
structural units of hepatic lipase in liver was 57 kDa and in adrenal and
ovary tissue 51 kDa. We conclude that the functional unit of hepatic
lipase in the liver is a monomer. The enzyme in adrenal gland and ovary is
different from the liver and the functional unit may be a dimer
Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings
A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)
Abrasive water jet drilling of advanced sustainable bio-fibre-reinforced polymer/hybrid composites : a comprehensive analysis of machining-induced damage responses
This paper aims at investigating the effects of variable traverse speeds on machining-induced damage of fibre-reinforced composites, using the abrasive water jet (AWJ) drilling. Three different types of epoxy-based composites laminates fabricated by vacuum bagging technique containing unidirectional (UD) flax, hybrid carbon-flax and carbon fibre-reinforced composite were used. The drilling parameters used were traverse speeds of 20, 40, 60 and 80 mm/min, constant water jet pressure of 300 MPa and a hole diameter of 10 mm. The results obtained depict that the traverse speed had a significant effect with respect to both surface roughness and delamination drilling-induced damage responses. Evidently, an increase in water jet traverse speed caused an increase in both damage responses of the three samples. Significantly, the CFRP composite sample recorded the lowest surface roughness damage response, followed by C-FFRP, while FFRP exhibited the highest. However, samples of FFRP and hybrid C-FFRP recorded lowest and highest delamination damage responses, respectively. The discrepancy in both damage responses, as further validated with micrographs of colour video microscopy (CVM), scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray μCT), is attributed to the different mechanical properties of the reinforced fibres, fibre orientation/ply stacking and hybridisation of the samples.Peer reviewe
Analysis of Yield Attributing Characters of Different Genotypes of Wheat in Rupandehi, Nepal
Field experiment was conducted at National Wheat Research Program, Bhairahawa, Rupandehi with the objective to identify high yielding superior wheat genotypes for Rupandehi district of Nepalduring 2014. Experiment was laid out in one factorial Randomized completely block design with ten wheat genotypes including both released and promising; Annapurna 1, Annapurna 3, Pasang Lahmu, Bijaya, BL 3623, Bhirkuti, NL 297, BL 4316, BL 3978 and BL 4347with three replications. The results showed that the grain yield of BL 3978 was found higher (4.03 t ha-1) than other genotypes followed by BL 4347 (3.93t ha-1). BL 3978 have also higher number of effective tillers m-2 and test weight. Among release varieties, NL 297 show higher yield (4 t ha-1) followed by Bhirkuti (3.43 t ha-1)and Bijaya (3.37 t ha-1). From this experiment it can be concluded that BL 3978 was found promising among all genotypes however should be tested at on-farms before promoted for general cultivation in Rupandehi district of Nepal
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Incomplete inhibition of phosphorylation of 4E-BP1 as a mechanism of primary resistance to ATP-competitive mTOR inhibitors
The mammalian target of rapamycin (mTOR) regulates cell growth by integrating nutrient and growth factor signaling and is strongly implicated in cancer. But mTOR is not an oncogene, and which tumors will be resistant or sensitive to new ATP-competitive mTOR inhibitors now in clinical trials remains unknown. We screened a panel of over 600 human cancer cell lines to identify markers of resistance and sensitivity to the mTOR inhibitor PP242. RAS and PIK3CA mutations were the most significant genetic markers for resistance and sensitivity to PP242, respectively; colon origin was the most significant marker for resistance based on tissue type. Among colon cancer cell lines, those with KRAS mutations were most resistant to PP242, while those without KRAS mutations most sensitive. Surprisingly, cell lines with co-mutation of PIK3CA and KRAS had intermediate sensitivity. Immunoblot analysis of the signaling targets downstream of mTOR revealed that the degree of cellular growth inhibition induced by PP242 was correlated with inhibition of phosphorylation of the translational repressor 4E-BP1, but not ribosomal protein S6. In a tumor growth inhibition trial of PP242 in patient-derived colon cancer xenografts, resistance to PP242 induced inhibition of 4E-BP1 phosphorylation and xenograft growth was again observed in KRAS mutant tumors without PIK3CA co-mutation, compared to KRAS WT controls. We show that, in the absence of PIK3CA co-mutation, KRAS mutations are associated with resistance to PP242 and that this is specifically linked to changes in the level of phosphorylation of 4E-BP1
Ultrasound-assisted green economic synthesis of hydroxyapatite nanoparticles using eggshell biowaste and study of mechanical and biological properties for orthopedic applications
Where is the jet quenching in Pb+Pb collisions at 158 AGeV?
Because of the rapidly falling particle spectrum at large from jet
fragmentation at the CERN SPS energy, the high- hadron distribution should
be highly sensitive to parton energy loss inside a dense medium as predicted by
recent perturbative QCD (pQCD) studies. A careful analysis of recent data from
CERN SPS experiments via pQCD calculation shows little evidence of energy loss.
This implies that either the life-time of the dense partonic matter is very
short or one has to re-think about the problem of parton energy loss in dense
matter. The hadronic matter does not seem to cause jet quenching in
collisions at the CERN SPS. High- two particle correlation in the
azimuthal angle is proposed to further clarify this issue.Comment: 4 pages with 2 ps figures. Minors changes are made in the text with
updated references. Revised version to appear in Phys. Rev. Letter
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Contemplating workplace change
Drawing on topical life histories of physicians in a particularly volatile public health sector environment, we build theory around the contemplation of workplace change. Overall, our study provides evidence as to why single or multiple independent factors, such as pay or job structure, may fail to predict or explain individual decisions to stay in or change workplaces. Instead, the contemplation process we argue is a complex, evolutionary, and context-dependent one that requires individualized interventions. Our findings reveal the prevalence of episodic context-self fit assessments prompted by triggering stimuli, two mechanisms by which thought processes evolved (reinforcement and recalibration), and four characteristic story lines that explain why the thought processes manifested as they did (exploring opportunities, solving problems, reconciling incongruence, and escaping situations). Based on our findings, we encourage practitioners to regularly engage in story-listening and dialogic conversations to better understand, and potentially affect the evolving socially constructed realities of staff members
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