1,737 research outputs found
Gas adsoprtion phenomenon in microporous zeolite adsorbent
Gas adsorption on zeolites gains remarkable attention in this new era of nanotechnology since it has industrial importance in many process industries. Efforts of chemists during the past few decades have advanced the field of synthesis and accelerated the development of zeolites with different physicochemical properties for specific application. New technologies involving gas separation, gas purification, gas storage, high temperature gas sensor, semiconductor material hold a great promise for industrial applications. In order to develop and design an efficient and economically feasible industrial adsorption process, it is important to understand the adsorption phenomena between solid and gas phases. The presence of metal cations in the extra-framework structure determines the accessibility of gas molecules into the zeolite framework. In addition, the selectivity and capacity of adsorption is also being influenced by the adsorbate-adsorbent interactions. The molecules may interact through dispersion, induction, field-quadrapole and/or repulsion forces. Hence, information on physicochemical properties of zeolites as well as the properties of adsorbent is equally important in order to understand gas adsorption phenomena in zeolite microstructures. Results of this study show that structural properties and adsorbate-adsorbent interactions affect gas adsorptive characteristics of zeolites
Duplex Doppler Ultrasonography for the Functional Evaluation of Diffuse Thyroid Diseases
It was reported in the literature that increased arterial flow in the thyroid was not only seen in Graves' disease with hyperthyroidism, but was also seen in Hashimoto's thyroiditis with hypothyroidism. Clinically, increased cardiac output is usually a sign of the former rather than the latter. Ultrasonographic assessment of the hemodynamic changes in the arteries of the systemic circulation, therefore, could be of value in differentiating between these two diffuse autoimmune diseases. Thus, it has been suggested that, for the functional evaluation of diffuse thyroid diseases, assessment of the peak systolic velocity of the thyroid arteries and the common carotid arteries should be performed ultrasonographically
Ultrasonographic Evaluation of Portal Hypertension and Liver Cirrhosis
Nowadays, ultrasonography is widely available in medical practice for the evaluation of liver cirrhosis and portal hypertension. Real-time ultrasonography (RTUS) is very convenient and is valuable in the detection of liver cirrhosis by demonstrating liver surface nodularity, splenomegaly and right lobe atrophy. Although RTUS is also utilized in the evaluation of portal hypertension by measuring the dimension of the main portal vein and visualizing the portosystemic collaterals, color Doppler ultrasonography (CDUS) and duplex Doppler ultrasonography (dDU) are undoubtedly superior to RTUS in this respect. With CDUS, the flow direction of the portal system can be clearly demarcated, and the collaterals, especially the gastroesophageal, the paraumbilical, the splenorenal and the gastrorenal veins, can be easily detected. With dDU, the measurement of portal flow velocities has been performed for the last two decades; yet, there is inter-equipment and interobserver variation. However, with the combination of the measurements relating to dimension and flow velocity of the main portal vein and changes in the right hepatic vein waveform, dDU is believed to be of value in the assessment of portal hypertension. In addition, several indices such as the congestion index, the portal hypertension index and the “liver cirrhosis index” have been applied in the evaluation of portal hypertension, with increasing evidence of simplicity and diagnostic accuracy. On the whole, ultrasonography is a modern imaging modality which plays an important role in the first-line diagnosis of liver cirrhosis and portal hyper-tension, because it is reliable, noninvasive and cost-effective
Chromosome Study of Arisaema of Taiwan
The chromosome number of most Arisaema plants was reported as 2n=28. Since species of Arisaema vary greatly in morphological features, comparative studies of anatomical, cytological, and other characteristics among the populations are required for more realistic taxonomic revision of this group. Two Taiwan species of Arisaema, A. formosana Hay. and A. consanguineum Schott, have been studied by the writer. Their chromosome numbers, obtained in mitosis, were 28 and 14 respectively
SYNTHESIS AND CHARACTERIZATION OF BTDA-ODA AND BPDA-ODA MEMBRANE
Recently, membrane is a separation process that has gained attention from different industries, especially membranes for gas separation processes such as removal of carbon dioxide from natural gas. From all the researches and findings, the most conventional polymeric membrane is the cellulose acetate membrane with low-cost as one of the benefits. In this research, the main focus will be on polyimide which is currently considered as a new kind of membrane with lesser reference compared with other kinds of membrane, thus it is proposed to be a replacement for cellulose acetate membrane, and a new alternative material for membrane fabrication. This research will mainly focus on the optimization of parameters of the fabrication of flat-sheet polyimide membrane using dry-wet phase inversion method. In this research, BTDA (3, 3’, 4, 4’ – benzophenonetetracarboxylic dianhydride) and BPDA (3, 3', 4, 4' – biphenyl tetracarboxylic dianhydride) are mixed with ODA (4, 4’ – dianiline) separately to form BTDA-ODA and BPDA-ODA using DMAc (N, N – dimethylacetamide) and DMF (dimethylformamide) as the solvent. Two different solvents are used to ensure poly amic acid with better viscosity. In the coagulation bath, water is used as the initial non-solvent for the precipitation of the membrane. Characterizations to be done are by using FESEM (Field Emission Scanning Electron Microscopy) and TGA (Thermal Gravimetry Analysis. Parameters such as concentration of polymers, choices and concentration of solvent and ratio of non-solvent are adjusted to perform optimization of the membrane fabrication
Effects of Gamma Irradiation on in Vitro Cultures of Selected Orchid Hybrids
Mutation breeding is an alternative strategy to conventional breeding.
The physical mutagen, gamma (y) radiation, has long been used in various
mutation breeding programmes. In this connection it is necessary to determine
the optimum dose before starting any mutation breeding programme.
In vitro cultured protocorm-like bodies (PLBs) of 2 orchid hybrids,
Mokara Chark Kuan and Dendrobium Jacky were used to study the effects of yirradiation
and to determine the optimum dose. The PLBs were irradiated with
y-rays at different doses of 0, 25, 50, 75, 100, 125 and 150 Grays (Gy) in Set I and 0, 20, 40, 60 and 80 Gy in Set II of the experiment. A senes of
observations on the effects of y-irradiation were recorded. Effects on genomic
DNA were also observed.
The present study showed that irradiation resulted in various degrees of
lethality to in vitro cultures of both Mokara Chark Kuan and Dendrobium
Jacky. Decrease in survival with increasing doses of y-irradiation was
significantly observed. Optimum dose of y-irradiation for in vitro cultures of
Mokara Chark Kuan and Dendrobium Jacky were estimated to be in the range
of 20-40 Gy and 60-70 Gy respectively.
Regeneration of plantlets was found to decline when higher irradiation
doses were applied. Irradiation also has inhibited regeneration of in vitro
cultures of both hybrids
Design and capacity performance analysis of wireless mesh network
Proceedings of: 5th International Conference on Mobile Technology, Applications, and Systems (Mobility 2008), (September 10-12, 2008), Yilan (Taiwan)From the network operator’s point of view, the high CAPEX/OPEX cost resulting from fixed/wired backhaul links can be inhibitive to successful deployment of broadband wireless services. The emerging wireless mesh network (WMN) technology is seen as one of the potential solutions which may reduce wired backhaul dependency through multihop transmission. Despite the advantages, many remain sceptical on WMN’s network capacity and scalability performances particularly when the user density is high. This paper provides an insight on the best possible upper-bound capacity performance of WMN, taking into consideration three key design parameters namely 1) Percentage of wired backhaul points per network, 2) Mesh-to-Access Link-Rate Ratio (R) and 3) Number of radio interfaces per mesh node including hybrid radio options. These design options are compared and contrasted with different deployment densities. The results generally show that the higher the number of backhaul points, the higher the effective access capacity available to mesh node and hence user domain. Increasing the R and the number of radio per mesh node are two alternative means to push up the effective access capacity per mesh node without increasing the number of wired backhaul points. This is most significant in multi radio system where about 80% of the backhaul points can be eliminated with R= 3 in order to maintain effective access capacity close to full rate (Capacity, C=1) per mesh node. It is also found that 50% of the backhaul points can be eliminated with R=2 for all radio options (except for the pure single radio case).European Community's Seventh Framework ProgramThis work was partially funded by the European Commission within the 7th Framework Program in the context of the ICT project CARMEN (Grant Agreement No. 214994) http://www.ict-carmen.eu
Development of Novel Primers and Probes Based on its 2 Region Using Nested-PCR and DNA Hybridization Array for Candida Species Identification
Sensitivity, specificity, simplicity, speed, and economy fairly well describe the desirable attributes of any clinical diagnostic test. In the mycology laboratory, the detection and differentiation of Candida species usually rely on the morphological, physiological, and biochemical characteristics which are complex, frequently slow to appear, sometimes vary within a species, and usually require significant experience to evaluate.
In this study, novel primers and probes had been developed for the identification of 8 Candida species using nested-PCR and DNA hybridization array by focusing on a single parameter. This parameter is the identification of nucleotide sequence from ITS 2 region that is known to be unique for the Candida species. These distinctive sequences were used to design and develop Candida species-specific primers and probes for nested-PCR and DNA hybridization array, respectively. For nested-PCR, the universal fungal primers, ITS 3 and ITS 4 were used to amplify the portion of the 5.8S and 28S rDNA, and the ITS 2 region of Candida species. The amplicons were used as template together with developed species-specific primers in the subsequent amplification. The results were analyzed using agarose gel electrophoresis. In addition, species-specific probes were used to hybridize to the biotinylated Candida species ITS 2 amplicons via DNA hybridization array. The amplicons were detected colorimetrically in strip format.
The sensitivity and specificity of the Candida species-specific primers and probes were evaluated. The 8 Candida ATCC strains and 24 clinical isolates did not exhibit cross-priming and cross-hybridization with the species-specific primers and probes in both assays and all the Candida species were correctly identified. In simulated clinical specimens, the sensitivity of the nested-PCR for Candida species detection was 10 cells/mL. However, the detection limit for both PCR using species-specific primers and DNA hybridization array using species-specific probes for the detection of Candida culture DNA was 1-10 cells/mL.
Additionally, a preliminary study was done for the screening of 40 healthy donors’ sera using the real-time PCR for the detection of Candida albicans using species-specific primers, CAL1 and CAL3. The melting curve was used for the analyses of the results. 3 out of 40 samples were found to be positive for Candida albicans. It is suggested that the real-time PCR may not be able to distinguish the individuals who are colonized from those who are infected.\ud
In conclusion, the nested-PCR and DNA hybridization array using the developed species-specific primers and probes, respectively, in this study are robust, sensitive and can be easily integrated into a clinical diagnostic laboratory with the potential for same-day diagnosis of Candida infection. In addition, the simultaneous differentiation of Candida species via DNA hybridization array allows faster and simpler diagnosis compare to nested-PCR. For real-time PCR screening of the healthy donors’ sera, further evaluation needs to be done to determine a threshold as standard guideline to detect the infectious and colonized Candida albicans and non-albicans Candida species
The Tie that Binds: The Impact of Self-Congruity and Brand Experience on Brand Attachment
This study extends brand attachment literature by investigating the effects of self-congruity types on brand attachment and bridging a gap concerning the mediating effect of brand experience on self-congruity-brand attachment linkage. The results indicate a direct effect between social self- congruity and brand attachment and a full mediation effect of brand experience on actual and ideal self-congruity and brand attachment. Also, the implications of this relationship differ by consumers’ need for uniqueness and self-regulatory focus
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