Spelling suggestions: "subject:"transporting"" "subject:"ransporting""
1 |
A study of conjugated polymers and their applications in light-emitting diodesDailey, Stuart January 1998 (has links)
The initiation of research into conjugated polymer electroluminescent devices in Durham is reported. The apparatus required for the fabrication and characterisation of polymer light-emitting diodes (LEDs) is outlined, and the essential assumptions and calculations required to determine their efficiency, brightness and colour are summarised. Optical and electrical characterisation of a range of polymers is reported, including polypyridine (PPY) and a range derivatives, poly(p-phenylene vinylene) (PPV) and poly(2-methoxy, 5-(2'ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV). The optical properties of PPY in solution, film and dilute solid state are characterised. The conjugation length of PPY is investigated by deliberate disruption of the conjugation by the inclusion meta-links in the otherwise para-linked polymer. The effect of altering the chemical structure of PPY is investigated by the study of some PPY derivatives including random and regular copolymers. The consequences of using precursor polymers, especially the effects of conversion on indium tin oxide coated substrates are investigated using absorption and luminescence spectroscopy and capacitance-voltage analysis. Electroluminescence from a number of conjugated polymers is reported and the efficiency, spectral output and device characteristics are presented. The formation of Schottky barriers in some polymer devices is investigated using quasi-static capacitance-voltage measurements. Improvements in the quantum and power efficiency of polymer LEDs have been achieved using two hole-transporting polymers, poly(vinyl carbazole) and the doped, conducting form of polyaniline. A substantial improvement in quantum efficiency has also been demonstrated when PPY is used as an electron-transporting layer in PPV and MEH-PPV based light-emitting diodes. The variation in quantum efficiency and emission spectrum with the ratio of the thickness of the two polymer layers is reported and analysed.
|
2 |
Regulation of the calcium transport atpase of rat heart sarcoplasmic reticulumMahey, Rajesh January 1986 (has links)
The sarcoplasmic reticulum Ca²⁺ -pumping ATPase is the primary system responsible for the removal of calcium from the sarcoplasm during relaxation of skeletal and cardiac muscles. Since the rat heart SR is used frequently in our laboratory to study the Ca²⁺ -transport defects in disease states, the Ca²⁺ -
ATPase activity of this system was characterized. Calmodulin
(CaM) and cAMP-dependent protein kinase (cAMP-PK) are known to
regulate the dog cardiac SR Ca²⁺ -pump. The effects of these
regulators on the rat heart SR Ca²⁺ -pump were studied. Studies
were also carried out to investigate the effects of Triton X-100 on SR Ca²⁺ -ATPase activity and the regulation of this activity by CaM.
The rat heart SR Ca²⁺-ATPase was stimulated in a concentration-dependent manner by both Ca²⁺ and Mg²⁺ in the complete absence of the other cation. Magnesium produced a concentration-dependent increase in the basal ATPase activity without affecting the maximal ATPase activity. This appeared to
result in a gradual disappearance of the Ca²⁺ dependency of the
ATPase activity. Addition of 100µM CDTA (trans-1,2-diaminocyclo-
hexane-N,N,N',N'-tetraacetic acid), in the absence of added
magnesium, produced no effect on Ca²⁺ stimulation of ATPase activity. The results appear to indicate the presence of a low affinity non-specific divalent cation-stimulated ATPase. At a constant Mg: ATP ratio, ATP simulated the SR Ca²⁺-ATPase activity in a concentration-dependent manner. Double-reciprocal plots of the data suggest that the true substrate for rat heart SR Ca²⁺-ATPase may be ATP and not Mg.ATP. In the crude SR, CaM did not stimulate total or Ca²⁺-stimulated ATPase activity over a range of Ca²⁺ and Mg²⁺
concentrations. CaM also failed to stimulate membrane phosphorylation over a range of Mg²⁺ concentrations. Furthermore, CaM
did not produce a significant effect on calcium transport into
SR vesicles. The catalytic subunit of cAMP-dependent protein
kinase was also ineffective in stimulating membrane phosphorylation and Ca²⁺ -ATPase activity. Two CaM antagonists, trifluperazine and compound 48/80, did not affect the rat heart SR ATPase activity.
The ATPase activity in Triton-washed SR membranes appeared to be increased at low Triton concentrations. This effect was probably due to the removal of non-intrinsic proteins, leaky vesicles or altered membrane fluidity. At higher Triton X-100 concentrations, the ATPase activity was lost, probably due to loss of the phospholipid environment.
When SR membranes phosphorylated under conditions similar to those used for the ATPase assay were analysed by SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) followed by autoradiography, a single phosphorylated protein of 7,500-9,000 dalton was observed. This protein may represent the monomeric form of phospholamban. CaM, however, appeared to have no effect on the phosphorylation of this 7,500-9,000 dalton protein in either untreated or Tritan-washed SR membranes. It is speculated that the rat heart SR contains tightly bound CaM which cannot be removed by treatment with Triton X-100. / Pharmaceutical Sciences, Faculty of / Graduate
|
3 |
Transportation of separate waste fractions in an underground waste transportation systemShibutani, Satomi January 2010 (has links)
Today waste management has entered a new stage. Since wastes still contain natural materials and energy that can be extracted, it should be treated in effective ways, for example, for energy recovery or material recycling. Many countries and the municipalities have therefore made waste treatment strategies in accordance with for example, EU directives or governmental regulations. In such circumstances, Envac is one of waste management companies in Sweden, which collects different kinds of waste fractions through an underground pipe system by means of air pressure. In Hammarby sjöstad in Stockholm, currently organic waste, combustible waste, and newspapers are collected by the Envac’s system, however a cross contamination between organic fraction and newspapers has been observed. We therefore performed on-site waste transporting experiments in order to solve this cross contamination and suggest an optimum transporting condition which means that waste bags can be transported with high rate and acceptable condition to the terminal. From the previous study, bag quality and transporting speed were supposed to be the factors that affect the waste purity. Then on-site experiments were designed and carried out based on these factors. In the end, we proposed the optimum condition depending on the bag quality and clarified the causes of the cross contamination.
|
4 |
Synthetic studies of plakortones. / CUHK electronic theses & dissertations collectionJanuary 2001 (has links)
Lee Hing Ken. / "November 2001." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 154-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
|
5 |
The study of organic solar cell featuring hole transporting layer with rubbing processChen, Yu-Jyun 24 August 2011 (has links)
In organic solar cell, the surface characteristic plays an important role in the power conversion efficiency of solar cell device. According to the literatures, the increased roughness can increase the contact area at the interface between PEDOT:PSS and active layer, improving hole extraction to the anode. Furthermore, a rough interface may cause a scattering effect on the incident light, which can reflect the out-lost-light back into the active layer and leads an efficient light absorbed. There are many ways to change the morphology of hole transporting layer, such as solvent-treated, or additives adding. However, the above process methods are easily affected by the external environmental conditions. It¡¦s difficult to get the surface morphology been well controlled, resulting in a process instability and low reproducibility.
In this research, we will create regular grooves on hole transporting layer by rubbing method. By changing baking temperature and rubbing pressure adjustment of PEDOT:PSS layer; we can precisely control the groove depth and surface morphology. This method makes the process simple and high stability. We found that the PEDOT:PSS hole transporting layer with a suitable depth grooves can enhance the power conversion efficiency. The power conversion efficiency of samples were measured under AM 1.5G 100mW/cm2 illumination. In our results, we found that the device possess about 14.52nm-depth of groove structure, the power conversion efficiency of devices can be increased from 2.03% to 2.36% (which is 17.6% improved). This consequence can be attributed to a short current density increasing from 5.67mA/cm2 to 6.67mA/cm2 based on the device structure is ITO(1500Å)/Rubbing-PEDOT:PSS(500Å)/P3HT:PCBM(800Å)/Al(2000Å).
|
6 |
Företagsklimat : En intervjustudie av transportföretag i Växjö kommun / Business environment : An interview study on transport companies in the Municipality of VäxjöElofsson, Tobias January 2015 (has links)
Bakgrund: Svenskt Näringsliv utför årligen undersökningen ”Lokalt näringsliv”, därföretagare får utvärdera sina respektive kommuner gällande det lokala företagsklimatet. I den senaste undersökningen framkommer det att transportbolagen är den generellt sätt minsta nöjda branshen i Växjö kommun. Ett gott företagsklimat är nyckeln till att skapa framgångsrika företag. Ett gott företagsklimat är ett ömsesidigt mål som både företagare och kommun strävar efter. Företagare kommer få en ökad sysselsättning vilket kommer leda till högre skatteintäkter för kommunen. Transportföretagens roll i värdekedjan har den senaste tiden fått allt större betydelse då det visat sig kunna generera konkurrensfördelar. Transportföretagen förväntas få en än större roll i framtiden med tanke på den pågående utvecklingen med e-handel. Att hitta orsakerna bakom transportföretagens eventuella missnöje gällande företagsklimatet är därför av högsta vikt för Växjö kommun i syfte att vara ett fortsatt intressant logistikläge. Syfte: Syftet med arbetet är att beskriva och förklara det upplevda nuläget gällande företagsklimatet i Växjö kommun samt gapet mellan transportföretagens förväntningar och upplevelse som orsakar ett eventuellt missnöje. Syftet är också att komma med förslag på områden som kan förbättras för att skapa ett gynnsamt företagsklimat för transportföretagen i Växjö kommun Metod: I arbetet har en intervjustudie av transportföretag i Växjö kommun genomförts. Empirisk data har insamlats genom semistrukturerade intervjuer med dels transportföretag i Växjö kommun men också med en anställd från Växjö kommuns trafikavdelning. Teoretisk data har samlats in genom litteraturstudie samt offentliga publikationer. Slutsats: I dagsläget är det ingen av respondenterna som är helnöjd med de variabler som enligt Svenskt Näringsliv påverkar ett företagsklimat, dock är det ingen som inte är nöjd med någon variabel heller. Utifrån de fyra variablerna ses företagares utrymme inom den offentliga verksamheten samt politiker och tjänstemäns attityder till företagande som de mest problematiska. Orsakerna bakom missnöjet framkom dels genom Svenskt Näringsliv variabler, dels genom fem variabler från SERVQUAL. De sex variabler som respondenterna var minst nöjda med bildade orsakerna bakom missnöjet. De sex variablerna var politiker och tjänstemäns attityder till företagande, förståelse av kund, tillgänglighet, kompetens, effektivitet, samt citylogistik. Citylogistiken samt klusterbyggande valdes som områden för förbättring. Citylogistiken då detta nämndes av samtliga respondenter som levererade gods till innerstaden. Klusterbyggande då detta ses som nyckeln till ett gott företagsklimat. Ett närmare samarbete företag emellan samt mellan Växjö kommun kommer skapa en bättre förståelse för varandra och hur parternas olika verksamheter fungerar. / Background: Svenskt Näringsliv conducts an annual survey called "Lokalt näringsliv", where business owners evaluate their own Municipalities regarding the local business environment. In the latest survey, it appears that transport companies are generally the least satisfied sector in the Municipality of Växjö. A good business environment is the key to creating a successful business. A good business environment is a mutual goal that both entrepreneurs and Municipalities endeavor. Business owners will get a higher employment which will lead to higher tax revenues for the Municipality. Transport companies role in the value chain have recently become increasingly important as it has proved to be able to create competitive advantages. Transport companies are expected to have an even greater role in the future given the ongoing development of e-commerce. To find the reasons behind the transport company’s dissatisfaction regarding the business environment is therefore essential in order to remain an interesting logistics location. Purpose: The purpose is to describe and explain the perceived current situation regarding the business environment in the Municipality of Växjö and the gap between the transport companies expectations and experience that causes the potential dissatisfaction. The purpose is also to make suggestions on actions to improve the transport company’s business environment. Method: This paper consists of an interview study on transport companies in the Municipality of Växjö. Empirical data were collected through semi-structed interviews with both transport companies in the Municipality of Växjö but also with an employee from Växjö Municipality traffic department. Theoretical data were collected through literature review and official publications. Conclusion: In the current situation, none of the respondents are totally satisfied with the variables that affects business environment according to Svenskt Näringsliv, however no one is satisfied with any variable either. Based on the four variables, entrepreneur’s scope in the public sector as well as politicians attitudes towards entrepreneurship is seen as the most problematic. The causes of the dissatisfaction were found partly by the variables from Svenskt Näringsliv and partly by five variables from SERVQUAL. The six variables that respondents were least satisfied with resulted in the reasons behind the dissatisfaction. The six variables were politicians and official’s attitudes towards entrepreneurship, understanding of the customer, availability, competence, efficiency, and urban logistics. Urban logistics as well as network building were chosen as areas for improvement. Urban logistics as this was mentioned by all respondents who deliver goods to the urban city. Network building as this is seen as the key to a goods business environment. Closer cooperation between companies and between the Municipality of Växjö and companies will create a better understanding of each other and how the partners various businesses operate.
|
7 |
Cryo-electron microscopy of Ca²⁺-ATPase from sarcoplasmic reticulum /Zhang, Peijun. January 1998 (has links)
Thesis (Ph. D.)--University of Virginia, 1998. / Spine title: Cryo-EM of Ca²⁺-ATPase from SR. Includes bibliographical references (p. 149-159). Also available online through Digital Dissertations.
|
8 |
Regulation of the Atp2b2 gene /Silverstein, Robert S., January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 124-135).
|
9 |
Roles of sarcoplasmic reticular ca2+ -atpase 2a and action potential duration in rat normal and hypertrophied myocardiumTaylor, David Glenn, January 2004 (has links)
Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 133 pages. Includes Vita. Includes bibliographical references.
|
10 |
Studies on the reaction cycle of the calcium transport atpase from human erythrocytesAllen, Bruce Gordon January 1985 (has links)
The plasma membrane calcium-transport ATPase plays a major role in maintaining the low cytosolic calcium concentrations required
for normal cellular function. Calcium, magnesium, calmodulin
and lanthanum have been shown to alter the activity of the calcium-stimulated, magnesium-dependent ATPase activity in human erythrocytes. In an attempt to examine the reaction sequence of the (Ca²⁺ + Mg²⁺)-ATPase, the effects of these agents on the kinetics of calcium dependent phosphoprotein formation, the first step in the partial reaction sequence, were examined. Calmo-dulin-depleted erythrocyte membranes were prepared by hypotonic lysis in the presence of EDTA, according to the method of Carafoli et al (1980).
Calcium-dependent formation of the phosphorylated intermediate
was biphasic; the high calcium-affinity component was associated with low levels of E.Ca.P and a shallow response to changing calcium concentrations, whereas in the region of the low calcium-affinity component, E.Ca.P rose sharply in response to increasing calcium concentrations. The low affinity component of E.Ca.P lies in the range of calcium concentrations which inhibit (Ca²⁺ + Mg²⁺)-ATPase activity. When analyzed on LiDS acid PAGE, both components of calcium-dependent phosphoprotein formation were due to hydroxylamine-sensitive phosphorylation of a 135,000-145,000 dalton protein. Hence, the low calcium-affinity component of phosphoprotein formation and calcium-dependent inhibition of (Ca²⁺ + Mg²⁺)-ATPase activity were likely due to calcium-inhibition of dephosphorylation. Kinetic studies of calcium-dependent phosphoprotein formation, at two different calcium concentrations (1.0 μM, 0.4 mM), indicated that a steady-state was reached much sooner at higher calcium concentrations. Lanthanum, which is known to block dephosphorylation of the intermediate
complex, increased both the apparent rate of formation and the steady-state level of the phosphorylated intermediate.
Calmodulin, which has previously been shown to increase both the maximum velocity and the calcium affinity of the (Ca²⁺ + Mg²⁺)-ATPase, did not affect either calcium-dependent inhibition of (Ca²⁺ + Mg²⁺ )-ATPase activity or the biphasic nature of calcium-dependent phosphoprotein formation. At low calcium concentrations, calmodulin increased the apparent rate of phosphoprotein
formation, whereas at higher calcium concentrations (0.4 mM) calmodulin reduced the steady-state level of the phosphoprotein; the apparent rate of formation was unaffected. In the presence of lanthanum, calmodulin increased both the apparent rate of formation and steady-state level of the phosphoprotein, suggesting that the true rate of formation was increased by calmodulin
at higher calcium concentrations, but this was normally hidden by a simultaneous increase in the rate of dephosphorylation.
Removal of endogenous magnesium, using trans-1,2-diamino-cyclohexane tetraacetic acid (CDTA) did not alter the calcium sensitivity or rate of formation of the phosphorylated intermediate,
however turnover of the intermediate was markedly reduced. In the absence of free magnesium, both the velocity and calcium sensitivity of the (Ca²⁺ + Mg²⁺)-ATPase were also found to be lower.
The low calcium-affinity component of calcium-dependent phosphoprotein formation, which Schatzmann (1982) has attributed to an action of calcium at a "magnesium-specific" site, was not affected by magnesium concentrations as high as 1 mM. Furthermore, this phosphoprotein could be dephosphorylated along either the forward or reverse pathways. These results indicate that the transformation from E₁.Ca.P to E₂.Ca.P may not be the site of the calcium-dependent inhibition of dephosphorylation.
Calmodulin-depleted membrane fragments were prepared from the erythrocytes of cystic fibrosis patients as well as age- and sex-matched controls. Under conditions in which dephosphoryla-tion is inhibited, phosphoprotein formation and (Ca²⁺ + Mg²⁺)-ATPase activities were determined. Both (Ca²⁺ + Mg²⁺)-ATPase activity and phoshoprotein formation were found to be significantly
reduced in the preparations derived from patients with cystic fibrosis. Turnover of the phosphorylated intermediate did not differ significantly between the two groups. A reduction in (Ca²⁺ + Mg²⁺)-ATPase activity and phosphoprotein formation suggests that there may be fewer active calcium-pumping sites in the erythrocyte membranes of cystic fibrosis patients compared to normal subjects. / Pharmaceutical Sciences, Faculty of / Graduate
|
Page generated in 0.0988 seconds