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Selected AbstractsService Personnel, Technology, and Their Interaction in Influencing Customer Satisfaction,DECISION SCIENCES, Issue 1 2006Craig M. Froehle ABSTRACT Managing both the technologies and the personnel needed for providing high-quality, multichannel customer support creates a complex and persistent operational challenge. Adding to this difficulty, it is still unclear how service personnel and these new communication technologies interact to influence the customer's perceptions of the service being provided. Motivated by both practical importance and inconsistent findings in the academic literature, this exploratory research examines the interaction of media richness, represented by three different technology contexts (telephone, e-mail, and online chat), with six customer service representative (CSR) characteristics and their influences on customer satisfaction. Using a large-sample customer survey data set, the article develops a multigroup structural equation model to analyze these interactions. Results suggest that CSR characteristics influence customer service satisfaction similarly across all three technology-mediated contexts. Of the characteristics studied, service representatives contribute to customer satisfaction more when they exhibit the characteristics of thoroughness, knowledgeableness, and preparedness, regardless of the richness of the medium used. Surprisingly, while three other CSR characteristics studied (courtesy, professionalism, and attentiveness) are traditionally believed to be important in face-to-face encounters, they had no significant impact on customer satisfaction in the technology-mediated contexts studied. Implications for both practitioners and researchers are drawn from the results and future research opportunities are discussed. [source] Mu-35: A Fluorogallophosphate Obtained by In Situ Generation of the TemplateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Louwanda Lakiss Abstract A two-dimensional microporous fluorogallophosphate, named Mu-35, closely related to ULM-8, was hydrothermally synthesized by in situ generation of the structure-directing agent. The precursor of the structure-directing agent is ethylformamide, which is generated in situ by decomposition, and goes on to form ethylamine molecules that act as templates in the medium used for the synthesis. The fluorogallophosphate Mu-35 (Mu is Mulhouse), Ga3(PO4)2(HPO4)F3(C2H8N)2(C2H7N)0.5 (Z = 8), crystallizes in the orthorhombic space group Pbcn with the following unit cell parameters: a = 22.117(1), b = 17.3740(8), c = 10.1550(4) Å. The structure of fluorogallophosphate Mu-35 was determined from single-crystal XRD data. It exhibits anionic layers composed of an unusual arrangement of three-, five-, and eight-membered rings (MR) [Ga2PO2F, Ga3P2O4F, and Ga3P3O8, respectively], and intercalated by protonated and nonprotonated ethylamine molecules. Mu-35 was also characterized by powder XRD, SEM, elemental and thermal analyses, and solid-state NMR spectroscopy (1H, 13C, 19F, and 31P MAS and 1H- 31P HETCOR experiments). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Solubility of root-canal sealers in water and artificial salivaINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2003E. Schäfer Abstract Aim, To compare the weight loss of eight different root-canal sealers in water and in artificial saliva with different pH values. Methodology, For standardized samples (n = 12 per group), ring moulds were filled with epoxy resin (AH 26, AH Plus)-, silicone (RSA RoekoSeal)-, calcium hydroxide (Apexit, Sealapex)-, zinc oxide,eugenol (Aptal-Harz)-, glass-ionomer (Ketac Endo)- and polyketone (Diaket)-based sealers. These samples were immersed in double-distilled water or artificial saliva with different pH values (7.0, 5.7 and 4.5) for 30 s, 1 min, 2 min, 5 min, 10 min, 20 min, 1 h, 2 h, 10 h, 24 h, 48 h, 72 h, 14 days and 28 days. Mean loss of weight was determined and analysed statistically using a one-way anova and Student,Newman,Keuls test for all pairwise comparisons. Results, Most sealers were of low solubility, although Sealapex, Aptal-Harz and Ketac Endo showed a marked weight loss in all liquids. Even after 28 days of storage in water, AH 26, AH Plus, RSA RoekoSeal, and Diaket showed less than 3% weight loss. At exposure times greater than 14 days, Sealapex showed the significantly greatest weight loss of all sealers tested (P < 0.05). Aptal-Harz and Ketac Endo were significantly more soluble in saliva (pH 4.5) than in water (P < 0.05). Conclusions, Under the conditions of the present study, AH Plus showed the least weight loss of all sealers tested, independent of the solubility medium used. Sealapex, Aptal-Harz and Ketac Endo had a marked weight loss in all liquids. [source] A finite element porothermoelastic model for dual-porosity mediaINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 9 2004R. Nair Abstract An existing dual-porosity finite element model has been extended to include thermo-hydro-mechanical coupling in both media. The model relies on overlapping distinct continua for the fluid and solid domains. In addition, conductive and convective heat transfers are incorporated using a single representative thermodynamics continuum. The model is applied to the problem of an inclined borehole drilled in a fractured formation subjected to a three-dimensional state of stress and, a temperature gradient between the drilling fluid and the formation. A sensitivity analysis has been carried out to study the impact of thermal loading, effect of heat transport by pore fluid flow and, the effect of parameters of the secondary medium used to represent the fractures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Structure, function and evolution of the gas exchangers: comparative perspectivesJOURNAL OF ANATOMY, Issue 4 2002J. N. Maina Abstract Over the evolutionary continuum, animals have faced similar fundamental challenges of acquiring molecular oxygen for aerobic metabolism. Under limitations and constraints imposed by factors such as phylogeny, behaviour, body size and environment, they have responded differently in founding optimal respiratory structures. A quintessence of the aphorism that ,necessity is the mother of invention', gas exchangers have been inaugurated through stiff cost,benefit analyses that have evoked transaction of trade-offs and compromises. Cogent structural,functional correlations occur in constructions of gas exchangers: within and between taxa, morphological complexity and respiratory efficiency increase with metabolic capacities and oxygen needs. Highly active, small endotherms have relatively better-refined gas exchangers compared with large, inactive ectotherms. Respiratory structures have developed from the plain cell membrane of the primeval prokaryotic unicells to complex multifunctional ones of the modern Metazoa. Regarding the respiratory medium used to extract oxygen from, animal life has had only two choices , water or air , within the biological range of temperature and pressure the only naturally occurring respirable fluids. In rarer cases, certain animals have adapted to using both media. Gills (evaginated gas exchangers) are the primordial respiratory organs: they are the archetypal water breathing organs. Lungs (invaginated gas exchangers) are the model air breathing organs. Bimodal (transitional) breathers occupy the water,air interface. Presentation and exposure of external (water/air) and internal (haemolymph/blood) respiratory media, features determined by geometric arrangement of the conduits, are important features for gas exchange efficiency: counter-current, cross-current, uniform pool and infinite pool designs have variably developed. [source] A novel finding that Streptomyces clavuligerus can produce the antibiotic clavulanic acid using olive oil as a sole carbon sourceJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008G. Efthimiou Abstract Aims:, This study aims to establish whether commercially available food oils can be used by Streptomyces clavuligerus as sole carbon sources for growth and clavulanic acid production. Methods and results:, Batch cultures in bioreactors showed that Strep. clavuligerus growth and clavulanic acid yields in a P-limited medium containing 0.6% (v/v) olive oil were respectively 2.5- and 2.6-fold higher than in a glycerol-containing medium used as control. Glycerol- and olive oil-grown cells present different macromolecular composition, particularly lipid and protein content. Conclusions:,Streptomyces clavuligerus uses olive oil as the sole carbon and energy source for growth and clavulanic acid production. Yields and production rates in olive oil are comparable to those reported for oil-containing complex media. Differences in yields and in the macromolecular composition indicate that different metabolic pathways convert substrate into product. Significance and impact of the study:, This is the first report of oils being used as the sole carbon source by Strep. clavuligerus. Apart from economic benefits, interesting questions are raised about Strep. clavuligerus physiology. Defined culture media allow physiological studies to be performed in the absence of interference by other compounds. Understanding how Strep. clavuligerus catabolises oils may have an economic impact in clavulanic acid production. [source] A cost effective fermentative production of succinic acid from cane molasses and corn steep liquor by Escherichia coliJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006L. Agarwal Abstract Aim:, Development and optimization of an efficient and inexpensive medium for succinic acid production by Escherichia coli under anaerobic conditions. Methods and Results:, Initially, 0·8 gl,1 of succinic acid was produced in 60 h in 300-ml medium. On optimization, glucose and peptone were replaced by cane molasses and corn steep liquor. Three hundred ml of this medium was inoculated with 4% (v/v) of seed inoculum, incubated at 39°C for 72 h, resulted in 7·1 gl,1 of succinic acid in 36 h. Scale up in a 10-l fermentor under conditions of controlled pH and continuous CO2 supply in this medium resulted in 17 gl,1 of succinic acid in 30 h. Conclusions:, A ninefold increase in succinic acid production was obtained in 500-ml anaerobic bottles with optimized medium having cane molasses and corn steep liquor as against initial medium containing glucose and peptone. However, a subsequent scale up in a 10-l fermentor resulted in a 2·5-fold increase in succinic acid production as against optimized medium used in 500-ml anaerobic bottles. Significance and Impact of the Study:, Succinic acid production was enhanced in medium consisting of inexpensive carbon and nitrogen sources in a shorter span of time. [source] Influence of oxidative stress and grains on sclerotial biomass and carotenoid yield of Penicillium sp.JOURNAL OF BASIC MICROBIOLOGY, Issue 4 2010Abstract Oxidative stress and grains were evaluated for carotenoid production by solid-state fermentation using Penicillium sp. PT95. When the fungus was grown at high oxidative stress, its sclerotial biomass and carotenoid content in sclerotia increased significantly with respect to low oxidative stress (P < 0.01). High oxidative stress also caused a statistically significant increase in carotenoid yield as compared with low oxidative stress (P < 0.01). Both the sclerotial biomass and the amount of carotenoid accumulated in sclerotia of strain PT95 were strongly dependent on the grain medium used. Among the grain media tested under high oxidative stress, buckwheat medium gave the highest content of carotenoid in sclerotia (828 ,g/g dry sclerotia), millet medium gave respectively the highest sclerotial biomass (12.69 g/100 g grain) and carotenoid yield (10.152 mg/100 g grain). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Participation of the secreted dipeptidyl and tripeptidyl aminopeptidases in asaccharolytic growth of Porphyromonas gingivalisJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2009H. Oda Background and Objective:,Porphyromonas gingivalis secretes gingipains, endopeptidases essential for the asaccharolytic growth of this bacterium. P. gingivalis also secretes dipeptidyl aminopeptidases (DPPIV and DPP-7) and a tripeptidyl aminopeptidase (PTP-A), although their role in asaccharolytic growth is unclear. The present study was carried out to elucidate the role of these dipeptidyl/tripeptidyl aminopeptidases on the asaccharolytic growth of P. gingivalis. Material and Methods:, Knockout mutants for the DPPIV (dpp), dpp7 and/or PTP-A genes were constructed. Brain,heart infusion medium supplemented with sterile hemin and menadione (BHIHM) was used as a complex medium, and the minimal medium used was GA, in which the sole energy source was a mixture of immunoglobulin G and bovine serum albumin. Growth of P. gingivalis was monitored by measuring the optical density of the culture. Results:, All knockout mutants for DPPIV, dpp7 and PTP-A grew as well as strain W83 in BHIHM. In GA, growth of single-knockout and double-knockout mutants was similar to that of W83, whereas growth of a triple-knockout mutant (83-47A) was reduced. We purified recombinant DPPIV and recombinant PTP-A from recombinant Escherichia coli overproducers, and purified DPP-7 from the triple-knockout mutant 83-4A. GA supplemented with the three purified dipeptidyl/tripeptidyl aminopeptidases supported the growth of 83-47A. Conclusion:, DPPIV, DPP-7 and PTP-A contribute to the normal growth of P. gingivalis by cleaving substrate peptides into short-chain polypeptides that are efficient energy sources for P. gingivalis. [source] Biological Control of Fusarium oxysporum f.sp. lycopersici on Tomato by Brevibacillus brevisJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2010Sunita Chandel Abstract The ability of Brevibacillus brevis to influence development of disease on tomato caused by Fusarium oxysporum f.sp. lycopersici was investigated using plants raised in Petri dish microcosms and in pots in the glasshouse. Development of symptoms on both microcosm- and glasshouse-raised tomato plants was markedly reduced in co-inoculations of F. oxysporum f.sp. lycopersici with B. brevis, compared with inoculations with the pathogen alone. Moreover, co-inoculations resulted in significant growth boosting effects on the plants, with increases in plant height in microcosms and in total root lengths in glasshouse-raised plants. In microcosm-raised plants, the carrier used to inoculate seed with B. brevis, either carboxymethyl cellulose (CMC) or vermiculite, had no effect on the persistence of the biological control agent on roots in the absence of inoculation with the pathogen. By contrast, numbers of B. brevis recovered from the rhizosphere and rhizoplane of inoculated plants in microcosms were four orders of magnitude lower than in plants treated with B. brevis alone. Moreover, higher numbers of B. brevis CFU were re-isolated from the rhizosphere of plants arising from CMC-coated seed, than vermiculite-coated seed. The carrier had no effect on disease control. Inhibition of conidial germination and germ-tube extension of F. oxysporum f.sp. lycopersici by cell-free filtrates of B. brevis cultures varied significantly depending on the culture medium used for suspension. These results indicate that B. brevis is a potential biological control agent for reducing the impact of F. oxysporum f.sp. lycopersici on tomato. [source] Solid-Based Hydrothermal Synthesis and Characterization of Alumina Nanofibers with Controllable Aspect RatiosJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2009Shou-Cang Shen Nanofibers of AlOOH with controllable aspect ratios have been synthesized by a facile steam-assisted solid-phase crystallization route. The morphology and aspect ratios of resulting AlOOH nanofibers were significantly influenced by the alkaline medium used in the preparation of solid precipitates from Al(NO3)3 solution. When tetramethylammonium hydroxide was used for precipitation, straight rod-like nanofibers with aspect ratios of 10,20 were obtained. The use of other tetra-alkylated ammonium hydroxides, such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide or tetrabutylammonium hydroxide, led to the formation of long wire-like nanofibers with aspect ratios up to 150. After thermal treatment at 600°C, the morphologies of the one-dimensional nanostructures were well preserved while the crystal structure was converted to ,-alumina. The wire-like nanofibers of alumina possessed higher thermal stability than alumina nanorods, and both exhibited much higher stability as compared with alumina micropowder. [source] Menstrum for culture preservation and medium for seed preparation in a tetanus toxin production process containing no animal or dairy productsLETTERS IN APPLIED MICROBIOLOGY, Issue 4 2006A. Fang Abstract Aims:, To completely eliminate animal and dairy products from the lyophilization menstrum and the seed medium used to produce tetanus toxin with Clostridium tetani. Methods and Results:, Tetanus toxin production in a recently developed fermentation medium lacking animal and dairy products was studied with different seed media. It was found that soy peptone could completely replace the beef heart infusion plus animal peptone previously used as seed medium. In addition, we found that cells lyophilized in soy milk could replace the usual type of cells lyophilized in cow's milk. Conclusions:, We have now developed a complete tetanus toxin production process containing no animal and dairy products. Significance and Impact of the Study:, Toxoid preparations made from toxin produced with animal and dairy products can contain undesirable contaminants such as the prion causing bovine spongiform encephalopathy (Mad Cow's Disease) or antigenic peptides that stimulate anaphylactic reactions and other undesirable immune reactions in immunized hosts. The new vegetable-based process described here avoids such unfortunate possibilities. [source] A host-vector system for molecular study of the intracellular growth of Mycobacterium tuberculosis in phagocytic cellsMICROBIOLOGY AND IMMUNOLOGY, Issue 10 2009Mari Nomoto ABSTRACT The mechanisms by which Mycobacterium tuberculosis survives and persists in phagocytic cells remain poorly understood. To study the question, a convenient and safe host-vector system is indispensable. In this study it has been shown that, in contrast with M. smegmatis strain mc2155 which has been widely used for molecular analysis, M. smegmatis strain J15cs is able to survive even at day 6 post-infection in a murine macrophage cell line, J774. The survivability of J15cs was found to depend on the culture medium used for the bacteria prior to infection. Bacteria precultured on nutrient agar medium showed a high survivability and a characteristic cell wall ultrastructure. A plasmid vector, pYT923hyg, was developed from an Escherichia coli - mycobacterium shuttle vector pYT923 (previously constructed in our laboratory) to obtain three drug resistant genes (amp-, hyg- and km-resistant gene) and cloning sites in the km resistant gene. The vector pYT923hyg exerted no influence on in vitro growth of J15cs and intracellular survival in J774 cells, and was stably retained in J15cs after serial subculturing (three subcultures) in Luria-Bertani broth and at day 5 post-infection into J774 cells. Furthermore, using this system, the possibility of a relationship between some seemingly essential genes of M. tuberculosis and intracellular growth was demonstrated. In this study, M. smegmatis strain J15cs and pYT923hyg were found to be capable of serving as an appropriate host-vector system for molecular study of the intracellular growth of M. tuberculosis in phagocytic cells; this system may be useful as a screening tool for M. tuberculosis genes. [source] Anaerobiosis inhibits gas vesicle formation in halophilic ArchaeaMOLECULAR MICROBIOLOGY, Issue 1 2009Torsten Hechler Summary The effect of anaerobiosis on the gas vesicle formation was investigated in three Halobacterium salinarum strains, Haloferax mediterranei and in Haloferax volcanii transformants. All these strains significantly reduced gas vesicle formation or lacked these structures under anoxic conditions. When grown by arginine fermentation, Hbt. salinarum PHH4 lacked gas vesicles, whereas Hbt. salinarum PHH1 and NRC-1 contained 5,20 small gas vesicles arranged in two to three aggregates per cell instead of the 30,80 gas vesicles present under oxic conditions. The enlargement presumably stopped due to a depletion of Gvp proteins. Also Hfx. mediterranei and Hfx. volcanii transformants lacked gas vesicles under anoxic growth and yielded a 10-fold reduced gvp transcription. Even the gas vesicle-overproducing ,D transformants did not form gas vesicles under anoxic conditions, demonstrating that the repressing protein GvpD was not involved. The presence of large amounts of GvpA implied that the assembly of the gas vesicles was inhibited. When Hbt. salinarum PHH1 and NRC-1 were grown with dimethyl sulphoxide or trimethylamine N -oxid under anoxic conditions the number but not the size of gas vesicles was reduced. This was in contrast to the previously reported overproduction of gas vesicles in NRC-1 that turned out to depend on the citrate-containing medium used for growth. [source] In vitro investigations on the mode of action of the hydroxypyridone antimycotics rilopirox and piroctone on Candida albicansMYCOSES, Issue 3 2006H. C. Sigle Summary Rilopirox and piroctone belong to the class of hydroxypyridone antimycotics. This class is not related to other antimycotics. In contrast to azole antimycotics and polyene antimycotics the mode of action of hydroxypyridone antimycotics is not fully understood. Inhibition of cellular uptake of essential compounds as well as loss of other compounds seems to be only a secondary effect of a primary not known action of these drugs. The antifungal effect in vitro depends on the medium used. The hyphal induction of Candida albicans is inhibited by hydroxypyridone antimycotics, but this effect is compensated by iron ions. A damage of the cell membrane and a direct influence on adenosine triphosphate synthesis, respectively, do not seem to be part of the mode of action. But there are clear hints that reactive oxygen species (ROS) and available metabolic activity are important parts of the mode of action of the hydroxypyridone antimycotics rilopirox and piroctone. [source] | |||||||||||||