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1.
Clin Radiol ; 76(7): 519-525, 2021 07.
Article in English | MEDLINE | ID: mdl-33736879

ABSTRACT

AIM: To compare the patency and safety of covered metallic stents (CMS) and the double-J stent (DJS) for treating malignant ureteral obstruction (MUO) in advanced gastric cancer (AGC). MATERIALS AND METHODS: Between 2016 and 2018, the medical records of 61 patients (84 ureters; CMS, 39 patients, 54 ureters; DJS, 22 patients, 30 ureters) with MUO caused by AGC were reviewed retrospectively. The Kaplan-Meier method and log-rank test were used to evaluate differences of primary or assisted primary patency between groups. Cox regression was conducted separately for early (within 7 days) and late (after 7 days) primary patency. RESULTS: Technical success of CMS placement was 100% (54/54) and 96.8% (29/30) for DJS (p=0.357). The cumulative stent patency rates at 1, 3, 6, and 12 months were 77%, 74%, 70%, and 70%, in the CMS group and 72%, 60%, 53%, and 26%, in the DJS group. Apart from the period within 7 days (p=0.784), primary patency was consistently higher in the CMS group when compared to the DJS group over the entire follow-up period (p=0.034). Assisted primary patency was consistently higher in the CMS group than in the DJS group over the entire follow-up period (p=0.001). The CMS group was more likely to have complications than the DJS group (48.1% versus 16.7%, p=0.004). Complications were minor, self-limiting events such as haematuria/haematoma. CONCLUSION: CMS had better late patency and assisted primary patency than DJS. Procedure-related minor complications more frequently occurred with CMS.


Subject(s)
Stents , Stomach Neoplasms/pathology , Ureteral Neoplasms/secondary , Ureteral Obstruction/etiology , Ureteral Obstruction/surgery , Aged , Female , Humans , Male , Middle Aged , Retrospective Studies , Self Expandable Metallic Stents , Tomography, X-Ray Computed , Ureteral Neoplasms/diagnostic imaging , Ureteral Obstruction/diagnostic imaging
2.
Rev Sci Tech ; 39(3): 1003-1015, 2020 Jan.
Article in English | MEDLINE | ID: mdl-35275120

ABSTRACT

The objective of this study was to evaluate the effectiveness of foot and mouth disease (FMD) control strategies using multi-criteria decision analysis (MCDA). The FMD control strategies were evaluated for epidemiological, economic and social-environmental criteria, accounting for the preferences of Chief Veterinary Officers (CVOs) from the Asia-Oceania region, with the preferences quantified using a questionnaire study. Previously reported simulation results of an FMD epidemic were used to measure the epidemiological effectiveness of FMD control strategies. The simulated FMD epidemic results, such as the number of infected farms, the duration of the epidemic and the outbreak area, were compared for a number of FMD control strategies. Based on previous simulation and economic modelling results and incorporating a literature search to quantify the social and environmental outcomes of an FMD outbreak, MCDA analysis was conducted to evaluate control strategies. According to the overall score in the MCDA results, an FMD control strategy which consisted of a 3-km radius of pre-emptive slaughter, 100 days of movement restriction and vaccinating all FMD-susceptible animals (baseline strategy) was the preferred strategy, with the highest overall score of 62.99. In contrast, the same duration of movement restriction and vaccination strategy with a 0.5-km radius of pre-emptive slaughter was least preferred, with the lowest overall score of 37.05. The evaluation of the FMD control strategies presented here using MCDA has provided scientific evidence for selecting an appropriate baseline FMD control strategy, based on the preferences of CVOs.


Les auteurs présentent les résultats d'une étude qui visait à évaluer l'efficacité d'un certain nombre de stratégies de lutte contre la fièvre aphteuse en recourant à une analyse décisionnelle multicritères (ADMC). Diverses stratégies de lutte contre la fièvre aphteuse ont été évaluées au regard de critères épidémiologiques, économiques et socio-environnementaux, en prenant en compte les préférences exprimées par les chefs des Services vétérinaires de la région Asie-Océanie, recueillies et quantifiées lors d'une étude par questionnaire. L'efficacité des stratégies de lutte contre la fièvre aphteuse au plan épidémiologique a été évaluée à partir des résultats d'une simulation d'épidémie de fièvre aphteuse effectuée au préalable. Les résultats de la simulation, notamment le nombre d'exploitations infectées, la durée de l'épidémie et l'extension de la zone focale, ont été comparés au regard de chacune des stratégies de lutte pouvant être appliquées contre la fièvre aphteuse. Une ADMC a été réalisée pour évaluer les stratégies de lutte en s'appuyant sur les résultats de simulations antérieures et de modélisations économiques, ainsi que sur les données réunies lors d'une recherche documentaire visant à quantifier les répercussions sociales et environnementales d'un foyer de fièvre aphteuse. Il ressort du classement des notes globales attribuées par l'ADMC que la stratégie préférée de lutte contre la fièvre aphteuse (note globale de 62,99) était celle associant l'abattage préventif dans un rayon de 3 km à une restriction des déplacements d'animaux pendant une période de 100 jours et à la vaccination de toutes les espèces sensibles au virus de fièvre aphteuse (stratégie de référence). En revanche, la stratégie associant une restriction des déplacements d'animaux de même durée, la vaccination et l'abattage préventif dans un rayon de 0,5 km recueillait le score le plus bas dans l'ordre de préférence (note globale de 37,05). Les évaluations des stratégies de lutte contre la fièvre aphteuse présentées par les auteurs à partir des résultats de l'ADMC fournissent des éléments scientifiques probants pour choisir une stratégie de référence appropriée afin de lutter contre la fièvre aphteuse, fondée sur les préférences des chefs des Services vétérinaires.


Los autores describen un estudio encaminado a evaluar la eficacia de distintas estrategias de control de la fiebre aftosa, para lo cual se siguió un proceso de análisis de decisiones con empleo de múltiples criterios de tipo epidemiológico, económico y socioambiental que recogían las preferencias de los jefes de los Servicios Veterinarios de la región Asia-Oceanía (preferencias cuantificadas con empleo de un cuestionario). Para medir la eficacia epidemiológica de las estrategias de lucha se utilizaron los resultados previamente descritos de simulaciones de una epidemia de fiebre aftosa. Después se compararon entre sí los resultados (por ejemplo, número de explotaciones infectadas, duración de la epidemia o territorio afectado por el brote) que deparaban distintas estrategias de lucha en una epidemia simulada de fiebre aftosa. A partir de los resultados de simulaciones y modelizaciones económicas anteriores e incorporando una búsqueda bibliográfica para cuantificar los efectos sociales y ambientales de un brote de fiebre aftosa, se procedió a evaluar las estrategias de lucha empleando el análisis de decisiones por criterios múltiples. A tenor de la puntuación global que arrojaban los resultados de este análisis, se determinó que la estrategia preferible de lucha contra la fiebre aftosa era la consistente en sacrificios sanitarios preventivos en un radio de 3 kilómetros, restricciones de desplazamientos durante 100 días y vacunación de todos los animales sensibles a la enfermedad (estrategia básica), pues era la que deparaba la puntuación global más elevada (62,99). La menos eficaz, es decir, la que deparaba la puntuación global más baja (37,05), preveía la aplicación de restricciones de desplazamientos durante el mismo período e idéntica estrategia de vacunación, pero con sacrificios sanitarios preventivos en un radio de solo 0,5 kilómetros. La evaluación de estrategias de lucha mediante un análisis de decisiones por criterios múltiples que aquí se presenta ha aportado sólidos datos científicos con los que seleccionar, partiendo de las preferencias de los jefes de los Servicios Veterinarios, una estrategia básica adecuada para combatir la fiebre aftosa.

3.
Clin Radiol ; 75(1): 57-63, 2020 01.
Article in English | MEDLINE | ID: mdl-31445764

ABSTRACT

AIM: To investigate the incidence and clinical characteristics of acute pancreatitis following percutaneous insertion of metallic biliary stents in patients with unresectable pancreatic cancer. The clinical efficacy of metallic stent insertion was also evaluated. MATERIALS AND METHODS: Data from 143 patients (75 men, 68 women; mean age, 65.8 years; range, 35-88 years) with unresectable pancreatic cancer who underwent percutaneous metallic biliary stent insertion between March 2007 and December 2017 were evaluated retrospectively. The incidence and clinical characteristics of acute pancreatitis were analysed. Stent patency and patient survival rates were calculated by Kaplan-Meier analysis. RESULTS: Technical success was achieved in all patients. Among 31 patients with serum amylase levels above normal values (30-110 U/l), only nine had symptoms of acute pancreatitis (incidence, 6.4%). No statistically significant risk factors were identified. Pancreatitis was successfully managed with conservative treatment at a mean of 2.9 days (range, 1-4 days). The median stent patency and patient survival times were 117 days (95% confidence interval [CI], 87-148 days) and 150 days (95% CI, 125-174.9 days), respectively. CONCLUSIONS: Acute pancreatitis was a relatively rare complication after percutaneous insertion of metallic biliary stents in patients with unresectable pancreatic cancer, and no significant risk factors were identified. Therefore, insertion of metallic biliary stents was seen to be a feasible and effective treatment approach in this patient group.


Subject(s)
Pancreatic Neoplasms/complications , Pancreatic Neoplasms/therapy , Pancreatitis/prevention & control , Stents , Adult , Aged , Aged, 80 and over , Female , Humans , Incidence , Male , Middle Aged , Palliative Care , Pancreatic Neoplasms/mortality , Pancreatitis/epidemiology , Pancreatitis/mortality , Retrospective Studies , Survival Rate
4.
J Appl Microbiol ; 118(3): 565-73, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25495284

ABSTRACT

AIMS: To identify whether the supplement of anaerobic fungi isolates with cellulolytic activities accelerates the silage fermentation. METHODS AND RESULTS: Three fungal isolates with the highest cellulolytic activities among 45 strains of anaerobic fungal stock in our laboratory were selected and used as silage inoculants. The rice straw (RS) was ensiled for 10, 30, 60, 90 and 120 days with four treatments of anaerobic fungi derived from the control (no fungus), Piromyces M014 (isolated from the rumen of the Korean native goat), Orpinomyces R001 (isolated from the duodenum of Korean native cattle) and Neocallimastix M010 (isolated from the guts of termites), respectively. The silages inoculated with pure strains of fungi showed a higher fungal population (P < 0.05) when compared to the control silage. In situ ruminal DM disappearance of RS silage (RSS) was improved with fungal treatment. SEM observation showed live fungal cells inoculated in RS could survive during the ensiling process. Overall, this study indicated that the inoculation of anaerobic fungi decreased the cell wall content of the RSS and increased in situ dry matter disappearance. CONCLUSIONS: The supplementation of anaerobic fungi isolates to RSS as a silage inoculant improves the RSS quality. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study showing the potential application of supplement of anaerobic fungi isolated from the guts may be applied industrially as an alternate feed additive that improves the silage quality.


Subject(s)
Fermentation , Fungi/metabolism , Oryza , Silage , Anaerobiosis , Animals , Cattle , Neocallimastigales/isolation & purification , Neocallimastix/isolation & purification , Piromyces/isolation & purification , Rumen/microbiology , Silage/microbiology
5.
Asian-Australas J Anim Sci ; 27(12): 1721-5, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25358365

ABSTRACT

The objective of this study was to evaluate the in vitro effects of coconut materials on ruminal methanogenesis and fermentation characteristics, in particular their effectiveness for mitigating ruminal methanogenesis. Fistulated Holstein cows were used as the donor of rumen fluid. Coconut materials were added to an in vitro fermentation incubated with rumen fluid-buffer mixture and timothy substrate for 24 h incubation. Total gas production, gas profiles, total volatile fatty acids (tVFAs) and the ruminal methanogens diversity were measured. Although gas profiles in added coconut oil and coconut powder were not significantly different, in vitro ruminal methane production was decreased with the level of reduction between 15% and 19% as compared to control, respectively. Coconut oil and coconut powder also inhibited gas production. The tVFAs concentration was increased by coconut materials, but was not affected significantly as compared to control. Acetate concentration was significantly lower (p<0.05), while propionate was significantly higher (p<0.05) by addition of the coconut materials than that of the control. The acetate:propionate ratio was significantly lowered with addition of coconut oil and coconut powder (p<0.05). The methanogens and ciliate-associated methanogens in all added coconut materials were shown to decrease as compared with control. This study showed that ciliate-associated methanogens diversity was reduced by more than 50% in both coconut oil and coconut powder treatments. In conclusion, these results indicate that coconut powder is a potential agent for decreasing in vitro ruminal methane production and as effective as coconut oil.

6.
Asian-Australas J Anim Sci ; 26(4): 517-22, 2013 Apr.
Article in English | MEDLINE | ID: mdl-25049817

ABSTRACT

The effect on methanogens attached to the surface of rumen ciliate protozoa by the addition of plant extracts (pine needles and ginkgo leaves) was studied with particular reference to their effectiveness for decreasing methane emission. The plant extracts (pine needles and ginkgo leaves) were added to an in vitro fermentation incubated with rumen fluid. The microbial population including bacteria, ciliated-associated methanogen, four different groups of methanogens and Fibrobacter succinogenes were quantified by using the real-time PCR. Gas profiles including methane, carbon dioxide and hydrogen, and runinal fermentation characteristics were observed in vitro. The methane emission from samples with an addition of individual juices from pine needles, ginkgo leaves and 70% ethanol extract from ginko leaves was significantly lower (p<0.05, 27.1, 28.1 and 28.1 vs 34.0 ml/g DM) than that of the control, respectively. Total VFAs in samples with an addition of any of the plant extracts were significantly lower than that of the control (p<0.05) as well. The order Methanococcales and the order Methanosarcinales were not detected by using PCR in any incubated mixtures. The ciliate-associated methanogens population decreased from 25% to 49% in the plant extacts as compared to control. We speculate that the supplementation of juice from pine needles and ginkgo leaves extract (70% ethanol extract) decreased the protozoa population resulting in a reduction of methane emission in the rumen and thus inhibiting methanogenesis. The order Methanobacteriales community was affected by addition of all plant extracts and decreased to less than the control, while the order Methanomicrobiales population showed an increase to more than that of the control. The F. succinogenes, the major fibrolytic microorganism, population in all added plant extracts was increased to greater than that of the control. In conclusion, pine needles and ginkgo leaves extracts appear to have properties that decrease methanogenesis by inhibiting protozoa species and may have a potential for use as additives for ruminants.

7.
Asian-Australas J Anim Sci ; 25(5): 653-8, 2012 May.
Article in English | MEDLINE | ID: mdl-25049610

ABSTRACT

This study was conducted to estimate the potential acid production value (PAPV) of major diets and to determine the relationship between dietary PAPV and dairy production traits. Estimation of PAPV of major cattle feeds was based on an in vitro technique, which determined the degree of Ca dissociation from CaCO3. Data on feeds and production traits were collected on 744 multiparous lactating Holstein dairy cows from five different farms. Grains had high PAPV with variable protein sources and by-products. High PAPV feedstuffs had a higher total gas production and lower pH compared to those with low PAPV. Dietary PAPV had a positive correlation with intake of dry matter, NDF, ADF, milk yield and milk solid production but a negative correlation with milk protein and milk fat concentration. Current results indicate that dietary PAPV can be utilized in predicting dairy production traits.

8.
Asian-Australas J Anim Sci ; 25(6): 806-11, 2012 Jun.
Article in English | MEDLINE | ID: mdl-25049630

ABSTRACT

This study was conducted to evaluate effects of plant extracts on methanogenesis and rumen microbial diversity in in vitro. Plant extracts (Artemisia princeps var. Orientalis; Wormwood, Allium sativum for. Pekinense; Garlic, Allium cepa; Onion, Zingiber officinale; Ginger, Citrus unshiu; Mandarin orange, Lonicera japonica; Honeysuckle) were obtained from the Plant Extract Bank at Korea Research Institute of Bioscience and Biotechnology. The rumen fluid was collected before morning feeding from a fistulated Holstein cow fed timothy and commercial concentrate (TDN; 73.5%, crude protein; 19%, crude fat; 3%, crude fiber; 12%, crude ash; 10%, Ca; 0.8%, P; 1.2%) in the ratio of 3 to 2. The 30 ml of mixture, comprising McDougall buffer and rumen liquor in the ratio of 4 to 1, was dispensed anaerobically into serum bottles containing 0.3 g of timothy substrate and plant extracts (1% of total volume, respectively) filled with O2-free N2 gas and capped with a rubber stopper. The serum bottles were held in a shaking incubator at 39°C for 24 h. Total gas production in all plant extracts was higher (p<0.05) than that of the control, and total gas production of ginger extract was highest (p<0.05). The methane emission was highest (p<0.05) at control, but lowest (p<0.05) at garlic extract which was reduced to about 20% of methane emission (40.2 vs 32.5 ml/g DM). Other plant extracts also resulted in a decrease in methane emissions (wormwood; 8%, onion; 16%, ginger; 16.7%, mandarin orange; 12%, honeysuckle; 12.2%). Total VFAs concentration and pH were not influenced by the addition of plant extracts. Acetate to propionate ratios from garlic and ginger extracts addition samples were lower (p<0.05, 3.36 and 3.38 vs 3.53) than that of the control. Real-time PCR indicted that the ciliate-associated methanogen population in all added plant extracts decreased more than that of the control, while the fibrolytic bacteria population increased. In particular, the F. succinogens community in added wormwood, garlic, mandarin orange and honeysuckle extracts increased more than that of the others. The addition of onion extract increased R. albus diversity, while other extracts did not influence the R. albus community. The R. flavefaciens population in added wormwood and garlic extracts decreased, while other extracts increased its abundance compared to the control. In conclusion, the results indicated that the plant extracts used in the experiment could be promising feed additives to decrease methane gas emission from ruminant animals while improving ruminal fermentation.

9.
J Biomed Biotechnol ; 2008: 547428, 2008.
Article in English | MEDLINE | ID: mdl-18317521

ABSTRACT

This article reports on a retinal stimulation system for long-term use in animal electrical stimulation experiments. The presented system consisted of an implantable stimulator which provided continuous electrical stimulation, and an external component which provided preset stimulation patterns and power to the implanted stimulator via a paired radio frequency (RF) coil. A rechargeable internal battery and a parameter memory component were introduced to the implanted retinal stimulator. As a result, the external component was not necessary during the stimulation mode. The inductive coil pair was used to pass the parameter data and to recharge the battery. A switch circuit was used to separate the stimulation mode from the battery recharging mode. The implantable stimulator was implemented with IC chips and the electronics, except for the stimulation electrodes, were hermetically packaged in a biocompatible metal case. A polyimide-based gold electrode array was used. Surgical implantation into rabbits was performed to verify the functionality and safety of this newly designed system. The electrodes were implanted in the suprachoroidal space. Evoked cortical potentials were recorded during electrical stimulation of the retina. Long-term follow-up using OCT showed no chorioretinal abnormality after implantation of the electrodes.


Subject(s)
Electric Stimulation/instrumentation , Evoked Potentials, Visual/physiology , Retina/physiology , Animals , Choroid/cytology , Electric Stimulation/adverse effects , Equipment Design , Equipment Failure Analysis , Feasibility Studies , Materials Testing , Prostheses and Implants , Rabbits , Retina/cytology
10.
J Thorac Cardiovasc Surg ; 121(5): 932-42, 2001 May.
Article in English | MEDLINE | ID: mdl-11326237

ABSTRACT

OBJECTIVE: The synthetic materials currently available for the repair of cardiac defects are nonviable, do not grow as the child develops, and do not contract synchronously with the heart. We developed a beating patch by seeding fetal cardiomyocytes in a biodegradable scaffold in vitro. The seeded patches survived in the right ventricular outflow tract of adult rats. METHODS: Cultured fetal or adult rat heart cells (1 x 10(6) cells) were seeded into a gelatin sponge (15 x 15 x 1 mm), and the cell number was expanded in culture for 1 or 3 weeks, respectively. The free wall of the right ventricular outflow tract in syngeneic adult rats was resected and repaired with either unseeded patches or patches seeded with either fetal or adult cardiomyocytes (n = 10 for each group). The patches were examined histologically over a 12-week period. RESULTS: A significant inflammatory reaction was noted in the patch at 4 weeks as the scaffold dissolved. At 12 weeks, the gelatin scaffold had completely dissolved. Both types of the seeded cells were detected in the patch with 5-bromo-2'-deoxyuridine staining, and they maintained their continuity. Unseeded patches had an ingrowth of fibrous tissue. The patches became thinner between the fourth and the twelfth weeks in unseeded (P =.003), fetal (P =.0001), and adult (P =.07) cardiomyocyte groups as the scaffold dissolved. The control patch, but not the cell-seeded patches, was thinner than the normal right ventricular outflow tract. The endocardial surface area of each patch was covered with endothelial cells identified by factor VIII staining. CONCLUSIONS: A gelatin patch was used to replace the right ventricular outflow tract in syngeneic rats. The seeded cells survived in the right ventricular outflow tract after the scaffold dissolved 12 weeks after implantation. In addition, the unseeded patches encouraged the ingrowth of fibrous tissue as the scaffold dissolved and the patches remained completely endothelialized.


Subject(s)
Absorbable Implants , Cell Transplantation , Heart Ventricles , Myocardium/cytology , Animals , Biocompatible Materials , Biomedical Engineering , Cells, Cultured , Gelatin Sponge, Absorbable , Heart Ventricles/cytology , Male , Rats , Rats, Inbred Lew , Transplantation, Isogeneic
11.
J Biochem ; 129(4): 513-20, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11275549

ABSTRACT

A series of truncated forms of gp91phox were expressed in Escherichia coli in which the N-terminal hydrophobic transmembrane region was replaced with a portion of the highly soluble bacterial protein thioredoxin. TRX-gp91phox (306-569), which contains the putative FAD and NADPH binding sites, showed weak NADPH-dependent NBT (nitroblue tetrazolium) reductase activity, whereas TRX-gp91phox (304-423) and TRX-gp91phox (424-569) were inactive. Activity saturated at about a 1:1 molar ratio of FAD to TRX-gp91phox (306-569), and showed the same K(m) for NADPH as that for superoxide generating activity by the intact enzyme. Activity was not inhibited by superoxide dismutase, indicating that it was not mediated by superoxide, but was blocked by an inhibitor of the respiratory burst oxidase, diphenylene iodonium. In the presence of Rac1, the cytosolic regulatory protein p67phox stimulated the NBT reductase activity, but p47phox had no effect. Truncated p67phox containing the activation domain (residues 199-210) [C.-H. Han, J.R. Freeman, T. Lee, S.A. Motalebi, and J.D. Lambeth (1998) J. Biol. Chem. 273, 16663-16668] stimulated activity approximately 2-fold, whereas forms mutated or lacking this region failed to stimulate the activity. Our data indicate that: (i) TRX-gp91phox (306-569) contains binding sites for both pyridine and flavin nucleotides; (ii) this flavoprotein domain shows weak diaphorase activity; and (iii) the flavin-binding domain of gp91phox is the target of regulation by the activation domain of p67phox.


Subject(s)
Flavoproteins/metabolism , Membrane Glycoproteins/chemistry , Membrane Glycoproteins/metabolism , NADPH Dehydrogenase/chemistry , NADPH Dehydrogenase/metabolism , NADPH Oxidases , Binding Sites , Biological Factors/pharmacology , Cloning, Molecular , Enzyme Activation , Enzyme Inhibitors/pharmacology , Flavin-Adenine Dinucleotide/metabolism , Flavin-Adenine Dinucleotide/pharmacology , Kinetics , Membrane Glycoproteins/antagonists & inhibitors , Membrane Glycoproteins/genetics , NADP/metabolism , NADP/pharmacology , NADPH Dehydrogenase/antagonists & inhibitors , NADPH Dehydrogenase/genetics , NADPH Oxidase 2 , Onium Compounds/pharmacology , Phosphoproteins/chemistry , Phosphoproteins/genetics , Phosphoproteins/metabolism , Protein Structure, Tertiary , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Sequence Deletion , Superoxide Dismutase/metabolism , Thermodynamics , rac1 GTP-Binding Protein/metabolism
12.
J Neurosci Methods ; 100(1-2): 17-23, 2000 Jul 31.
Article in English | MEDLINE | ID: mdl-11040362

ABSTRACT

Silicidation of the Co/refractory metal/Si system in which the refractory metal is used as an epitaxy promoter for CoSi(2) has recently received much attention. Hf is one of the candidates for the epitaxy promoter of cobalt silicide like Ti. In this paper, we investigated the layer structures of the Co/Hf bilayer on various substrates like single (100)Si, polycrystalline Si and SiO(2) after rapid thermal annealing. Epitaxy of CoSi(2) was obtained on (100)Si by annealing Co/Hf/(100)Si. Co-Hf compounds seem to play an important role of barriers against the reaction between Co and Si during silicidation of Co/Hf/(100)Si. The existence of Co-Hf compounds is helpful in the formation of epitaxial CoSi(2) since they retard the diffusion of cobalt and silicon atoms. The transition temperatures of cobalt silicides in the Co/Hf/poly-Si system were found to be lower than those in the Co/Hf/(100)Si system. The reaction between the metal and the spacer SiO(2) during silicidation is a matter of concern since any conducting residue of this reaction could degrade oxide integrity or produce bridging. In the Co/Hf/SiO(2) system Hf oxides formed as a result of the reaction between Hf and SiO(2) but a conducting material like HfSi(2) was not found to form after annealing. Considering the temperature at which epitaxial CoSi(2) forms along with the one from which the SiO(2) substrate starts collapsing we may conclude that the optimum silicidation annealing temperature for Co/Hf/Si is 600 degrees C.


Subject(s)
Cobalt/chemistry , Electrophysiology/instrumentation , Hafnium/chemistry , Oxygen/chemistry , Silicones/chemistry , Transistors, Electronic/standards , Crystallization , Temperature , X-Ray Diffraction/methods
13.
Talanta ; 52(6): 1143-8, 2000 Sep 05.
Article in English | MEDLINE | ID: mdl-18968077

ABSTRACT

A series of calixcrown ethers for which the cavity size of the crown ring is varied from crown-6 to crown-7 to crown-8 were examined for the transport abilities toward alkali metal ions. These ligands were incorporated into supported liquid membranes (SLMs) and into polymer inclusion membranes (PIMs) composed of cellulose triacetate (CTA) as a support and 2-nitrophenyl octyl ether (NPOE) and tris(2-butoxyethyl) phosphate (TBEP) as a plasticizer. In both membrane systems, calixcrown-6 showed the best selectivity toward a cesium ion over other alkali metal ions. The polymeric CTA membrane showed more rapid transport rate as well as higher durability than did the SLMs.

14.
Biochem Biophys Res Commun ; 202(3): 1697-704, 1994 Aug 15.
Article in English | MEDLINE | ID: mdl-8060359

ABSTRACT

The effect of several tyrosine kinase inhibitors was tested on Ca2+ influx mediated by thapsigargin-and CCh-induced intracellular store depletion. Genestein inhibited Ca2+ influx in a concentration dependent manner without affecting Ca2+ release or Ca2+ pumping activity. A measureable effect was observed at 3 microM with total inhibition of influx seen at 100 microM. Tyrphostin A25 (300 microM; 78% inhibition) and methyl 2,5 dihydroxycinnamate (10 microM; 51% inhibition) also inhibited Ca2+ influx. The degree of attenuation was not markedly altered by preincubation of the inhibitors. Genestein also inhibited Ca2+ influx induced by CCh. These data indicate that inhibition of Ca2+ influx could in part underlie the previously reported inhibition of enzyme secretion by these agents.


Subject(s)
Calcium/metabolism , Catechols/pharmacology , Cinnamates/pharmacology , Isoflavones/pharmacology , Nitriles/pharmacology , Pancreas/drug effects , Protein-Tyrosine Kinases/antagonists & inhibitors , Tyrphostins , Animals , Barium/metabolism , Carbachol/pharmacology , Genistein , Ion Transport/drug effects , Male , Pancreas/metabolism , Rats , Rats, Sprague-Dawley , Terpenes/pharmacology , Thapsigargin
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