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1.
Food Chem ; 455: 139920, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38850994

RESUMEN

This work presents a hydrothermal method followed by a sonochemical treatment for synthesizing tantalum decorated on iron selenide (Ta/FeSe2) integrated with nitrogen-doped graphene (NGR) as a susceptible electrode material for detecting trolox (TRX) in berries samples. The surface morphology, structural characterizations, and electrochemical performances of the synthesized Ta/FeSe2/NGR composite were analyzed via spectrophotometric and voltammetry techniques. The GCE modified with Ta/FeSe2/NGR demonstrated an impressive linear range of 0.1 to 580.3 µM for TRX detection. Additionally, it achieved a remarkable limit of detection (LOD) of 0.059 µM, and it shows a high sensitivity of 2.266 µA µÐœ-1 cm-2. Here, we used density functional theory (DFT) to investigate the structures of TRX and TRX quinone and the locations of energy levels and electron transfer sites. The developed sensor exhibits significant selectivity, satisfactory cyclic and storage stability, and notable reproducibility. Moreover, the practicality of TRX was assessed in different types of berries, yielding satisfactory recoveries.

2.
Chemosphere ; 358: 142237, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38705406

RESUMEN

In this study, a novel Ce2MgMoO6/CNFs (cerium magnesium molybdite double perovskite decorated on carbon nanofibers) nanocomposite was developed for selective and ultra-sensitive detection of ciprofloxacin (CFX). Physical characterization and analytical techniques were used to explore the morphology, structure, and electrocatalytic characteristics of the Ce2MgMoO6/CNFs nanocomposite. The sensor has a wide linear range (0.005-7.71 µM and 9.75-77.71 µM), a low limit of detection (0.012 µM), high sensitivity (0.807 µA µM-1 cm-2 nM), remarkable repeatability, and an appreciable storage stability. Here, we used density functional theory to investigate CFX and oxidized CFX as well as the locations of the energy levels and electron transfer sites. Furthermore, the Ce2MgMoO6/CNFs-modified electrode was successfully tested in food samples (milk and honey), indicating an acceptable response with a recovery percentage and relative standard deviation of less than 4%, which is comparable to that of GC-MS. Finally, the developed sensor exhibited high selectivity and stability for CFX detection.


Asunto(s)
Carbono , Ciprofloxacina , Miel , Leche , Nanocompuestos , Nanofibras , Óxidos , Nanocompuestos/química , Ciprofloxacina/análisis , Ciprofloxacina/química , Óxidos/química , Leche/química , Nanofibras/química , Animales , Miel/análisis , Carbono/química , Molibdeno/química , Límite de Detección , Compuestos de Calcio/química , Titanio/química , Teoría Funcional de la Densidad , Técnicas Electroquímicas/métodos , Cerio/química , Contaminación de Alimentos/análisis , Electrodos , Magnesio/química , Magnesio/análisis
3.
Environ Pollut ; 356: 124196, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38788992

RESUMEN

This study involved the synthesis of a Ce2Sn2O7/Ag3PO4/V@g-C3N4 composite through hydrothermal methods, followed by mechanical grinding. The resulting heterojunction exhibited improved catalytic activity under visible light by effectively separating electrons and holes (e-/h+). The degradation of Tartrazine (TTZ) reached 93.20% within 50 min by employing a ternary composite at a concentration of 10 mg L-1, along with 6 mg L-1 of PS. The highest pseudo-first-order kinetic constant (0.1273 min-1 and R2 = 0.951) was observed in this system. The dual Z-scheme heterojunction is developed by Ce2Sn2O7, Ag3PO4, and V@g-C3N4, and it may increase the visible light absorption range while also accelerating charge carrier transfer and separation between catalysts. The analysis of the vulnerability positions and degradation pathways of TTZ involved the utilization of density functional theory (DFT) and gas chromatography-mass spectrometry (GC-MS) to examine the intermediate products. Therefore, Ce2Sn2O7/Ag3PO4/V@g-C3N4 is an excellent ternary nanocomposite for the remediation of pollutants.

4.
Neurocrit Care ; 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38253924

RESUMEN

BACKGROUND: External ventricular drain (EVD) is used for monitoring intracranial pressure or diverting cerebrospinal fluid. However, confirmation of an infection is not immediate and requires obtaining culture results, often leading to the excessive use of antibiotics. This study aimed to compare noninfectious ventriculitis and EVD infection in terms of the risk factors, predictors, prognosis, and effectiveness of care bundle interventions. METHODS: This retrospective study was conducted at a medical center with 1,006 beds in northern Taiwan between January 2018 and July 2022. Standard EVD insertion protocols and care bundles have been implemented since 2018, along with the initiation of chlorhexidine. RESULTS: In total, 742 EVD cases were identified. Noninfectious ventriculitis typically presents with fever approximately 8 days following EVD placement, whereas EVD infection typically manifests as fever after 20 days. Aneurysmal subarachnoid hemorrhage was strongly associated with the development of noninfectious ventriculitis (adjusted odds ratio [OR] 2.6, 95% confidence interval [CI] 1.5-4.4). Alcoholism (adjusted OR 3.5, 95% CI 1.1-12.3) and arteriovenous malformation (adjusted OR 13.1, 95% CI 2.9-58.2) significantly increased the risk of EVD infection. The EVD infection rate significantly decreased from 3.6% (14 of 446) to 1.0% (3 of 219) (p = 0.03) after the implementation of chlorhexidine gluconate bathing. CONCLUSIONS: Aneurysmal subarachnoid hemorrhage or fever with neuroinflammation within 2 weeks of EVD placement is indicative of a higher likelihood of noninfectious ventriculitis. Conversely, patients with arteriovenous malformation, alcoholism, or fever with neuroinflammation occurring after more than 3 weeks of EVD placement are more likely to necessitate antibiotic treatment for EVD infection. Chlorhexidine gluconate bathing decreases EVD infection.

5.
Sensors (Basel) ; 23(11)2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-37299943

RESUMEN

Surface plasmon resonance (SPR) sensing is a real-time detection technique for measuring biomolecular interactions on gold surfaces. This study presents a novel approach using nano-diamonds (NDs) on a gold nano-slit array to obtain an extraordinary transmission (EOT) spectrum for SPR biosensing. We used anti-bovine serum albumin (anti-BSA) to bind NDs for chemical attachment to a gold nano-slit array. The covalently bound NDs shifted the EOT response depending on their concentration. The number of ND-labeled molecules attached to the gold nano-slit array was quantified from the change in the EOT spectrum. The concentration of anti-BSA in the 35 nm ND solution sample was much lower than that in the anti-BSA-only sample (approximately 1/100). With the help of 35 nm NDs, we were able to use a lower concentration of analyte in this system and obtained better signal responses. The responses of anti-BSA-linked NDs had approximately a 10-fold signal enhancement compared to anti-BSA alone. This approach has the advantage of a simple setup and microscale detection area, which makes it suitable for applications in biochip technology.


Asunto(s)
Técnicas Biosensibles , Resonancia por Plasmón de Superficie , Técnicas Biosensibles/métodos , Oro/química , Albúmina Sérica Bovina/química , Resonancia por Plasmón de Superficie/métodos , Nanotecnología , Diamante
6.
Front Neurol ; 14: 1149236, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37213896

RESUMEN

Managing acute innominate artery (IA) dissection associated with severe stenosis is challenging due to its rarity, possible complex dissection patterns, and compromised blood flow to the brain and upper extremities. This report describes our treatment strategy for this challenging disease using the kissing stent technique. A 61-year-old man had worsening of an acute IA dissection secondary to an extension of a treated aortic dissection. Four possible treatment strategies for kissing stent placement were proposed based on different approaches (open surgical or endovascular) and accesses (trans-femoral, trans-brachial, or trans-carotid access). We chose to place two stents simultaneously via a percutaneous retrograde endovascular approach through the right brachial artery and a combined open surgical distal clamping of the common carotid artery with a retrograde endovascular approach through the carotid artery. This hybrid approach strategy highlights the three key points for maintaining safety and efficacy: (1) good guiding catheter support is obtainable through retrograde, rather than antegrade, access to the lesion, (2) concomitant cerebral and upper extremity reperfusion is guaranteed by placing kissing stents into the IA, and (3) peri-procedural cerebral emboli are prevented by surgical exposure of the common carotid artery with distal clamping.

7.
J Clin Med ; 12(7)2023 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-37048551

RESUMEN

Proton pump inhibitors (PPIs) are widely prescribed in medical practice for the treatment of several gastrointestinal disorders. Previous epidemiology studies have reported the association between PPI use and the risk of AKI, although the magnitude of the association between PPIs and the risk of acute kidney injury (AKI) remains uncertain. Therefore, we conducted a meta-analysis to determine the relationship between PPI therapy and the risk of AKI. We systematically searched for relevant articles published before January 2023 on PubMed, Scopus, and Web of Science. In addition, we conducted a manual search of the bibliographies of potential articles. Two independent reviewers examined the appropriateness of all studies for inclusion. We pooled studies that compared the risk of AKI with PPI against their control using a random effect model. The search criteria based on PRISMA guidelines yielded 568 articles. Twelve observational studies included 2,492,125 individuals. The pooled adjusted RR demonstrated a significant positive association between PPI therapy and the risk of AKI (adjusted RR 1.75, 95% CI: 1.40-2.19, p < 0.001), and it was consistent across subgroups. A visual presentation of the funnel plot and Egger's regression test showed no evidence of publication bias. Our meta-analysis indicated that persons using PPIs exhibited an increased risk of AKI. North American individuals had a higher risk of AKI compared to Asian and European individuals. However, the pooled effect from observational studies cannot clarify whether the observed association is a causal effect or the result of some unmeasured confounding factors. Hence, the biological mechanisms underlying this association are still unclear and require further research.

8.
Clin Neuroradiol ; 33(2): 319-325, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36056108

RESUMEN

PURPOSE: Rete middle cerebral artery (MCA) anomaly is characterized by a web-like network of arteries involving the first MCA segment (M1) and a normal downstream MCA. The detailed composition of this anomaly and the hemodynamic impacts on cerebral perfusion are rarely addressed. The purpose of this study was to elucidate the anatomical and hemodynamic perspectives of the rete MCA anomaly. METHODS: From August 2020 to December 2021, 4 rete MCA anomalies were identified at Shuang Ho hospital. Clinical information, perfusion magnetic resonance (MR) imaging, and angiographic images were collected. Detailed angioarchitecture, including types of arterial feeders and extent of rete involvement, were analyzed based on three-dimensional volume-rendering reconstruction images obtained from the catheter-based angiographies. RESULTS: Despite their variable clinical presentations (two hemorrhage, one ischemia, and one asymptomatic), all cases shared common angiographic findings as follows: (1) the internal carotid artery did not connect directly to the rete, (2) the anterior choroidal artery (AChA) was the artery constantly supplying the rete and (3) there was a watershed zone shift toward MCA territory. The perfusion MR cerebral blood flow map was symmetric in all studied cases. CONCLUSION: The AChA is an artery constantly supplying the rete, which suggests that the angioarchitectural features associated with this anomaly may be the result of both congenital and acquired compensatory processes. Cerebral perfusion remains preserved at the lesion side, despite angiographic evidence of watershed zone shift. These findings will be important for making better clinical judgments about this condition.


Asunto(s)
Relevancia Clínica , Arteria Cerebral Media , Humanos , Arteria Cerebral Media/diagnóstico por imagen , Arteria Cerebral Media/cirugía , Arterias Cerebrales , Arteria Carótida Interna , Angiografía por Resonancia Magnética , Angiografía Cerebral
9.
Sensors (Basel) ; 22(17)2022 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-36080864

RESUMEN

Detecting pesticides using techniques that involve simple fabrication methods and conducting the detection at very low levels are challenging. Herein, we report the detection of acetamiprid at the quadrillionth level using surface-enhanced Raman scattering (SERS). The SERS chip comprises Ag nanoparticles deposited on a tetrapod structure of ZnO coated onto indium tin oxide glass (denoted as Ag@ZnO-ITO). Controlled Ag decoration of ZnO occurs via irradiation-induced synthesis. The morphology of the surface plays a significant role in achieving an enhanced SERS performance for acetamiprid detection. 4,4'-Dipyridyl (DPY) is used to investigate synthesis conditions for the chip, leading to an optimal irradiation time of 60 min. Furthermore, the enhancement factor for acetamiprid on Ag@ZnO-ITO is higher than 107. These results demonstrate that SERS sensors have the potential for practical use in acetamiprid detection.


Asunto(s)
Nanopartículas del Metal , Plaguicidas , Óxido de Zinc , Nanopartículas del Metal/química , Neonicotinoides , Plaguicidas/análisis , Plata/química , Espectrometría Raman/métodos , Óxido de Zinc/química
10.
J Surg Case Rep ; 2021(8): rjab334, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34405041

RESUMEN

Vertebro-venous fistula (VVF) refers to an abnormal arteriovenous shunt connecting the extracranial vertebral artery and the paraspinal venous structures. Coil embolization is the mainstay treatment of choice for VVF, and accurate definition of the endovascular target is mandatory. Traditionally, catheter-based angiograms are used for treatment planning, but those images lack bony information to delineate the precise relationship of the drainage veins to the spinal structure. Herein, we presented two VVF cases and demonstrated how we used intra-arterial cone-beam computed tomography angiography (IA-CBCTA) to determine the safe embolization zone for dense coil packing. We propose that IA-CBCTA is a useful adjunct in the endovascular planning of VVF by offering an image consisting of bony and vascular information.

11.
Nanomaterials (Basel) ; 9(3)2019 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-30897840

RESUMEN

We control the nanoscale gaps on silver island films by different processing methods and investigate the surface-enhanced Raman scattering (SERS) efficiency on the films. We propose a facile technique to control the film morphology by substrate bending while keeping the evaporation rate constant. The films developed by our new method are compared to the films developed by traditional methods at various evaporation rates. The SERS signals generated on the samples prepared by the new method have similar strengths as the traditional methods. Substrate bending allows us to reduce the gap sizes while using a higher evaporation rate, hence the film can be developed in a shorter time. This cost-effective and time-efficient method is suitable for the mass production of large-area SERS sensors with good sensitivity. Scanning electron microscope images are analyzed to quantify the gap densities and widths to elucidate the relationship between the film morphology and the SERS intensity. While the gap size appears to be the major factor influencing the enhancement, the shape of the nano-island also seems to influence the SERS efficiency.

12.
Opt Express ; 24(14): 16132-48, 2016 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-27410880

RESUMEN

A rigorous full-vector multi-mode fiber (MMF) model is proposed. It is believed to be the first comparative study of vector and scalar MMF model in terms of differential mode delay (DMD), mode power distribution (MPD), transfer functions as well as eye diagrams. It shows that the vector nature of fiber modes cannot be ignored even though the refractive index difference can be as small as 1%. A standard-compliant methodology for MMF characterization is introduced. The impact of fiber parameters on bandwidth is studied. The statistical transfer function model of OM3 and OM4 fiber is provided. These transfer functions can be applied to the MMF link modeling. Rigorous full-vector MMF model is an essential tool for research and development of MMF link transceivers and standard development of 112Gbps and beyond.

13.
Kaohsiung J Med Sci ; 30(9): 477-83, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25224772

RESUMEN

Healthcare professionals have a high risk of needlestick and sharps injuries (NSIs), which have a high potential for disease transmission. Ambulatory care follow up is essential, but is usually overlooked. This study aimed to investigate the annual and cumulative (age-, sex-, and subtype-specific) incidences of ambulatory care visits after NSIs. This study was also designed to evaluate the incidences of blood-borne diseases associated with NSIs among Taiwanese health professionals in Taiwan between 2004 and 2010. Data were obtained from the National Health Insurance Research Database, which contains anonymized records representing approximately 99% of the Taiwan population. A total of 4443 nurse healthcare workers (NHCWs) and 3138 non-nurse healthcare workers (NNHCWs), including physicians, medical technologists, and other health professionals were included in this longitudinal study. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. The Mantel-Haenszel method was used to adjust for sex, age, and type of affiliation. Results showed that the annual incidence of ambulatory care visits of NHCWs increased from 0.7% in 2004 to 1.9% in 2010; this incidence was significantly higher than that of NNHCWs (from 0.3% in 2004 to 0.5% in 2010) in any yearly comparison (p < 0.05). The sex-adjusted 7-year cumulative incidence rate was 3.23 (95% CI = 1.23-8.45) in males and 3.92 (95% CI = 2.70-5.69) in females (p < 0.05). The age-adjusted 7-year cumulative incidence rate was 2.74 (95% CI = 1.99-3.77) and 2.14 (95% CI = 1.49-3.07) in subjects ≤ 30 and ≥31 years old, respectively (p < 0.0005). The affiliation-adjusted 7-year cumulative incidence rate was 1.89 (95% CI = 1.21-2.94) in medical centers and 3.33 (95% CI = 2.51-4.41) in nonmedical centers (p < 0.01). In conclusion, NSIs increased steadily from 2004 to 2010 in Taiwan with NHCWs having higher NSIs incidences than NNHCWs. A routine ambulatory care visit after NSIs can prevent blood-borne transmission, especially for NHCWs. Educational programs may be helpful for reducing the incidence of NSIs and increasing ambulatory care visit ratios after NSIs.


Asunto(s)
Atención Ambulatoria/estadística & datos numéricos , Personal de Salud/estadística & datos numéricos , Encuestas Epidemiológicas/estadística & datos numéricos , Lesiones por Pinchazo de Aguja/epidemiología , Adulto , Factores de Edad , Enfermedades Transmisibles/etiología , Demografía , Femenino , Humanos , Incidencia , Masculino , Lesiones por Pinchazo de Aguja/complicaciones , Enfermeras y Enfermeros/estadística & datos numéricos , Factores de Riesgo , Taiwán/epidemiología
14.
Vaccine ; 29(44): 7740-6, 2011 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-21835218

RESUMEN

Actinobacillus pleuropneumoniae is a gram-negative bacterial pathogen that causes swine pleuropneumonia, a highly contagious and often fatal disease that occurs worldwide. Our previous study showed that DNA vaccines encoding Apx exotoxin structural proteins ApxIA and/or ApxIIA, are a promising novel approach for immunization against the lethal challenge of A. pleuropneumoniae serotype 1. Vaccination against A. pleuropneumoniae is impeded by the lack of vaccines inducing reliable cross-serotype protection. Type IV fimbrial protein ApfA has been shown to be present and highly conserved in various serotypes of A. pleuropneumoniae. A novel DNA vaccine encoding ApfA (pcDNA-apfA) was constructed to evaluate the protective efficacy against infection with A. pleuropneumoniae serotype 2. A significant antibody response against pilin was generated following pcDNA-apfA immunization, suggesting that it was expressed in vivo. The IgG subclass (IgG1 and IgG2a) analysis indicates that the pcDNA-apfA vaccine induces both Th1 and Th2 immune responses. The IgA analysis shows that mucosal immunity could be enhanced by this DNA vaccine. Nevertheless, the strong antibody response induced by pcDNA-apfA vaccine only provided limited 30% protective efficacy against the serotype 2 challenge. These results in this study do not coincide with that the utility of type IV pilin is a good vaccine candidate against other infectious pathogens. It indicates that pilin should play a limited role in the development of a vaccine against A. pleuropneumoniae infection.


Asunto(s)
Infecciones por Actinobacillus/veterinaria , Actinobacillus pleuropneumoniae/inmunología , Vacunas Bacterianas/inmunología , Proteínas Fimbrias/inmunología , Pleuroneumonía/prevención & control , Vacunas de ADN/inmunología , Infecciones por Actinobacillus/inmunología , Infecciones por Actinobacillus/prevención & control , Actinobacillus pleuropneumoniae/genética , Animales , Anticuerpos Antibacterianos/sangre , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/genética , Modelos Animales de Enfermedad , Proteínas Fimbrias/administración & dosificación , Proteínas Fimbrias/genética , Inmunidad Mucosa , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Ratones , Ratones Endogámicos BALB C , Pleuroneumonía/inmunología , Análisis de Supervivencia , Células TH1/inmunología , Células Th2/inmunología , Vacunas de ADN/administración & dosificación , Vacunas de ADN/genética
15.
Opt Express ; 18(20): 20595-609, 2010 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-20940954

RESUMEN

To facilitate the analysis of radiation mode couplings, quasi leaky mode approximations were utilized in coupled-mode analysis. The key to effectively and accurately apply this approach is how to well approximate radiation modes by the quasi leaky modes in an equivalent closed waveguide model. In this paper, the principle, applicability and accuracy of the approximations are demonstrated, and the detailed implementation is also suggested by applying a unified coupled-mode analysis to fiber gratings. First of all, based on a thorough study on the characteristics of the complex modes, for the first time, quasi leaky modes are classified into guided-mode-like inner-cladding and radiation-mode-like outer-cladding leaky modes so as to explicitly establish equivalence relationships between the discrete leaky modes and the continuous radiation modes. With this new insight, the whole analysis process especially for some of the practically tricky issues such as the criteria for developing the proper equivalent waveguide model and the subsequent mode expansion basis are better understood and easier to be dealt with for different problems where radiation modes come into play. Moreover, as essential preconditions to extend the conventional coupled mode analysis to the present unified one, the couplings between the guided core mode and a leaky mode are studied in a systematic and consistent manner. An intuitive and then a deep understanding on the roles of complex modes on mode coupling and power exchanging are thus gained for further simulations. Lastly, the transmission spectra of fiber gratings with different surrounding indices are simulated. The simulated results agree well with those obtained theoretically and experimentally in the literatures, which strongly validate the principle of quasi leaky mode approximations and its implementation on the unified coupled-mode analysis expounded in this paper.

16.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 26(4): 318-21, 2010 Apr.
Artículo en Chino | MEDLINE | ID: mdl-20368107

RESUMEN

AIM: To construct a siRNA plasmid to knockdown Coronin-1. METHODS: The cDNA of coronin-1 was amplified by RT-PCR from the total RNA of macrophage, and then inserted into pSEB-HUS vector to generate pSEB-HUS-C plasmid. Three synthesized siRNAs targeting Coronin-1 were cloned into pSEB-HUS-C respectively, resulting in the pSEB-HUS-C1, pSEB-HUS-C2 and pSEB-HUS-C3 plasmids. These plasmids were transiently transfected into A549, and the Coronin-1 level was detected by RT-PCR, Real time PCR and Western blot. RESULTS: All plasmids were successfully constructed as confirmed by restriction enzyme digestion and DNA sequencing. The pSEB-HUS-C3 vector had the most significant knockdown effect on Coronin-1, with 75.9% inhibition at mRNA level and 75.1% inhibition at protein level. CONCLUSION: A siRNA plasmid targeting Coronin-1 was successfully constructed and validated for its knockdown effect, which will serve as a loss-of-function tool for the further mechanistic study of Coronin-1 in tuberculosis pathology.


Asunto(s)
Técnicas de Silenciamiento del Gen/métodos , Proteínas de Microfilamentos/deficiencia , Proteínas de Microfilamentos/genética , Plásmidos/genética , ARN Interferente Pequeño/genética , Animales , Western Blotting , Línea Celular Tumoral , Humanos , Ratones , Proteínas de Microfilamentos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Recombinantes de Fusión/deficiencia , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
17.
Opt Express ; 18(2): 713-26, 2010 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-20173891

RESUMEN

A full vector complex coupled mode theory (CMT) for the analysis of tilted fiber gratings is presented. With the combination of the perfectly matched layer (PML) and the perfectly reflecting boundary (PRB), the continuous radiation modes are well represented by a set of discrete complex modes. Simulation of coupling to radiation modes is greatly simplified and may be treated in the same fashion as guided modes. Numerical results of the tilted fiber Bragg gratings (TFBGs) with outer-cladding index equal, lower and higher than that of the inner-cladding indicate that the complex coupled mode approach is highly effective in the simulation of couplings to cladding and radiation modes in tilted fiber gratings. The reflective TFBGs are investigated by the proposed approach in detail.


Asunto(s)
Modelos Teóricos , Refractometría/instrumentación , Simulación por Computador , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Luz , Rotación , Dispersión de Radiación
18.
Biochem Biophys Res Commun ; 355(1): 23-7, 2007 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-17291451

RESUMEN

We have previously produced transgenic G-InsKi mice, a model allowing regulated portal insulin delivery from gastric G cells without using beta cells. Here, we report that in G-InsKi mice portal levels of transgenic human insulin are 6-fold higher than in peripheral circulation. Peptone-induced release of transgenic human insulin from G cells preferentially stimulated signaling cascades in the liver rather than in peripheral insulin-sensitive tissues, as judged by tyrosine phosphorylation of insulin receptor beta subunit and phosphorylation of protein kinase Akt/PKB at Thr-308. G-InsKi mice provide a novel animal model for elucidating direct effects of insulin on liver functions.


Asunto(s)
Células Secretoras de Gastrina/metabolismo , Insulina/metabolismo , Hígado/metabolismo , Animales , ADN Complementario/genética , Ingestión de Alimentos , Humanos , Secreción de Insulina , Ratones , Ratones Transgénicos , Receptor de Insulina/efectos de los fármacos , Receptor de Insulina/fisiología , Proteínas Recombinantes/metabolismo , Transducción de Señal
19.
Endocrinology ; 146(6): 2610-9, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15731364

RESUMEN

We explored the hypothesis that meal-regulated release of insulin from gastric G cells can be used for gene therapy for diabetes. We generated transgenic mice in which the coding sequence of human insulin has been knocked into the mouse gastrin gene. Insulin was localized specifically to antral G cells of G-InsKi mice by double immunofluorescence staining using antibodies against insulin and gastrin. Insulin extracted from antral stomach of G-InsKi mice decreased blood glucose upon injection into streptozotocin-diabetic mice. Intragastric administration of peptone, a known potent luminal stimulant of gastrin secretion, induced an increase in circulating levels of transgenic human insulin from 10.7 +/- 2 to 23.3 +/- 4 pm in G-InsKi mice. Although G cell-produced insulin decreased blood glucose in G-InsKi mice, it did not cause toxic hypoglycemia. Proton pump inhibitors, pharmacological agents that increase gastrin output, caused a further increase in the circulating levels of gastric insulin (41.5 +/- 2 pm). G cell-produced insulin was released into circulation in response to the same meal-associated stimuli that control release of gastrin. The most striking aspect of the results presented here is that in the presence of the G-InsKi allele, Ins2(Akita/+) mice exhibited a marked prolongation of life span. These results imply that G cell-derived transgenic insulin is beneficial in the amelioration of diabetes. We suggest that an efficient G cells-based insulin gene therapy can relieve diabetic patients from daily insulin injections and protect them from complications of insulin insufficiency while avoiding episodes of toxic hypoglycemia.


Asunto(s)
Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 2/terapia , Células Secretoras de Gastrina/fisiología , Terapia Genética/métodos , Insulina/genética , Animales , Glucemia/metabolismo , Diabetes Mellitus Experimental/tratamiento farmacológico , Ingestión de Alimentos , Mucosa Gástrica/citología , Mucosa Gástrica/fisiología , Gastrinas/genética , Humanos , Hiperglucemia/terapia , Hipoglucemiantes/farmacología , Insulina/metabolismo , Insulina/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos
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