1000 resultados para MICELLAR MEDIUM


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A direct force-measuring technique has been used to study the interaction forces between adsorbed CTAB (cetyltrimethylammonium bromide) bilayers at concentrations well above the CMC (critical micelle concentration). An analysis of these results based on the Poisson-Boltzmann equations leads to the conclusion that CTAB micelles and adsorbed bilayers are about 22(±4)% dissociated. The apparent agreement of bilayer and micellar ion binding parameters raises an important challenge for theories of double-layer interactions. In addition, the double-layer decay lengths observed in these micellar solutions appear to be due entirely to the dissociated bromide and free CTA+ ions, with no apparent contribution from charged micelles.

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This paper is concerned with explaining the levels of innovative activity in New Zealand's SMEs. It is arguable that New Zealand provides a special case where innovation and R&D levels are comparatively low in SMEs, yet, paradoxically, it is also a nation of high rates of entrepreneurial activity. This paper seeks to examine the factors that affect innovation levels in New Zealand SMEs from an analysis of panel data set of 1500 SMEs. We test research propositions based on existing theory and literature on innovation levels in SMEs and discuss our findings. Firm size is found to be significant; we argue that New Zealand has too few growth firms rather than too many small firms and we suggest that barriers to innovation, such as access to finance, remain an issue which should be a focus for government support.

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This paper presents a conceptual framework showing formal and informal institutions and their relationship with the strategic choice of micro, small, and medium enterprises (MSMEs) in a developing country setting. It emphasises how institutions at sub-national level (such as a region or city) influence the strategic orientations of MSMEs as many developing countries in Asia are undergoing decentralisation whereby sub-national government authorities are given more political, economic, fiscal, and administrative powers. Furthermore, it sheds more insights on the environmental (institutional) determinism-organisational (strategic) choice nexus. It offers propositions, questions as well as issues worth pursuing in empirical investigations in the future.

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This article proposes a conceptual framework that explains that the social capital of a community shapes the innovation performance of small and medium-sized enterprises (SMEs) through knowledge management within the firm. The study's significance stems from the unprecedented effort in explaining how community social capital matters in the innovation performance of SMEs, a departure from previous studies that have typically examined market-related or hierarchical social capital in the form of formal networks and directly linked them to a firm's innovation performance without due regard for knowledge management within the firm as an antecedent of organisational innovation performance. The aim is to stimulate further thinking and empirical research on the subject of social capital of a community in the SME and/or entrepreneurial context.

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Objectives: Visual analog scales are frequently used as a means of allowing participants to rate symptoms during clinical trials. The accuracy and reproducibility of these scales play an important role in determining the experimental value of the data they provide. This study was initiated to compare the data collected using paper- and computer-based (Tablet PC) analog scales to better understand the variability in data provided by a visual analog scale.

Methods: Thirty participants rated ocular comfort, redness, and clarity of vision (right and left eyes) on a nondemarcated horizontal line on both paper and a Tablet PC. Measurements were taken in the morning between the hours of 8:30 and 10:30 am and again the same day between 2:30 and 4:30 pm.

Results: The mean difference between the measures recorded in the morning for the 2 media was 2.6 ± 0.9 (confidence intervals, 2 standard errors of the differences) units on a 100 unit scale, with the Tablet PC having the higher mean measure. The limits of agreement (2 standard deviations of the differences) was 9.4 units. Comparing the difference of the differences (1.0 ± 1.3) between the 2 methods of measure (morning vs. afternoon) the visual analog scales on the Tablet PC seemed to have good reproducibility of agreement in comparison with the paper version.

Conclusions: Discrepancy analysis yielded no significant difference and slight bias between paper- and computer-based analog scales. Repeatability of measures using the Tablet PC was also demonstrated. These results suggest that the choice of medium does not significantly influence the outcome for subjective analog scales.

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Selective production of fragrance fatty acid ester from isopropanol and acetic acid has been achieved using silica-immobilizedlipase of Bacillus cereus MTCC 8372. A purified thermoalkalophilic extracellular lipase was immobilized by adsorption onto the silica. The effects of various parameters like molar ratio of substrates (isopropanol and acetic acid; 25 to 100 mM), concentration ofbiocatalyst (25–125 mg/mL), reaction time, reaction temperature, organic solvents,molecular sieves, and initial water activity werestudied for optimal ester synthesis. Under optimized conditions, 66.0mM of isopropyl acetate was produced when isopropanol and acetic acid were used at 100mM: 75mM in 9h at 55◦C in n-heptane under continuous shaking (160 rpm) using bound lipase(25mg). Addition of molecular sieves (3 °A ×1.5mm) resulted in a marked increase in ester synthesis (73.0mM). Ester synthesiswas enhanced by water activity associated with pre-equilibrated saturated salt solution of LiCl. The immobilized lipase retained more than 50% of its activity after the 6th cycle of reuse.

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Given the proliferation of wine brands, developing a brand without understanding its impact on wine choice is a risky business; particularly for SMEs with limited financial resources.

This paper fills an important gap in the wine marketing literature, particularly as it relates to SMEs in the sector, by investigating the effect of the brand on wine choice. Surveying a range of wine consumers, it was found that while the brand was relevant in wine choice the weighted importance of the brand elements changed across consumption situations. This novel finding should assist SMEs to grow their businesses beyond the traditional cellar door.

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This paper reports a study of the critical determinants for adopting electronic markets (e-Market) in Australian small-and-medium sized enterprises (SMEs) within the technology-organization-environment (TOE) framework. Structural equation modelling and logistic regression are used for identifying the critical determinants for the adoption of e-Markets by Australian SMEs through testing a proposed conceptual model and proposing an alternative model. This study contributes to existing research by enriching an understanding of the critical determinants of adopting an e-Market in Australian SMEs and by providing a validated model for the interrelationships of the determinants in technology adoption.

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In this work, LaMO3 and LaNi0.5M0.5O3 (M = Ni, Co, Fe, Mn and Cr) perovskite oxide electrocatalysts were synthesized by a combined ethylenediaminetetraacetic acid-citrate complexation technique and subsequent calcinations at 1000 °C in air. Their powder X-ray diffraction patterns demonstrate the formation of a specific crystalline structure for each composition. The catalytic property of these materials toward the oxygen reduction reaction (ORR) was studied in alkaline potassium hydroxide solution using the rotating disk and rotating ring-disk electrode techniques. Carbon is considered to be a crucial additive component because its addition into perovskite oxide leads to optimized ORR current density. For LaMO3 (M = Ni, Co, Fe, Mn and Cr)), in terms of the ORR current densities, the performance is enhanced in the order of LaCrO3, LaFeO3, LaNiO3, LaMnO3, and LaCoO3. For LaNi0.5M0.5O3, the ORR current performance is enhanced in the order of LaNi0.5Fe0.5O3, LaNi0.5Co0.5O3, LaNi0.5Cr0.5O3, and LaNi0.5Mn0.5O3. Overall, LaCoO3 demonstrates the best performance. Most notably, substituting half of the nickel with cobalt, iron, manganese, or chromium translates the ORR to a more positive onset potential, suggesting the beneficial catalytic effect of two transition metal cations with Mn as the most promising candidate. Koutecky–Levich analysis on the ORR current densities of all compositions indicates that the four-electron pathway is favored on these oxides, which are consistent with hydroperoxide ion formation of <2%.

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Network technologies are very desirable for social action, allowing activists to achieve more with less, more quickly and with broader impact; on the other hand, the very advantages they bring are equally important to the world of contemporary capitalism that social action seeks to change. Thus, we must look beyond network technologies as the easy solution to every problem, and focus instead on the human relationships which might be enabled by them. This focus on relationships requires us to ‘de-tool’ information technology. Instead, for social action, it is more valuable to think of networked computing as part of the environment within which action can occur; an important purpose for such action; and as a medium that nurtures expression and engagement of self and belief.

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The present study discusses the status of quality management practices in manufacturing SMEs in Australia and investigates the reasons why they are not implementing the Six Sigma methodology. This study emphasises that Six Sigma can be implemented in manufacturing SMEs. Moreover, this study identifies the motivation for adopting Six Sigma by Australian manufacturing SMEs. A Six Sigma implementation framework is developed and presented.