Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Chemphyschem ; : e202400505, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38978281

RESUMEN

In the catalytic transformation of bio-oil into liquid fuels having alkanes via hydrodeoxygenation (HDO), the acid and metal sites in the catalyst are pivotal for promoting the HDO of lignin-derived phenolic compounds. This study introduces a novel bifunctional catalyst comprising phosphomolybdenum-vanadium heteropolyacids (H4PMo11VO40) coupled with Ni/C. The HDO reaction of the model compound guaiacol was carried out under reaction conditions of 230 °C, revealing the superior performance of H4PMo11VO40 with Ni/C catalysts compared to the conventional acids, even at low dosage. The Keggin structure of H4PMo11VO40 provided a solid catalyst with strong acidic and redox properties, alongside advantages such as ease of synthesis, cost-effectiveness, and tunable acid and redox properties at the molecular level. Characterization of Ni/C and the prepared acid demonstrated favorable pore structure with a mesopore volume of 0.281 cm3/g and an average pore size of 3.404 nm, facilitating uniform distribution and catalytic activity of Ni-metal. Incorporating acid enhances the acidic sites, fostering synergistic interactions between metal and acidic sites within the catalyst, thereby significantly enhancing HDO performance. Guaiacol conversion at 230 °C reached 100%, with a cyclohexane selectivity of 89.3%. This study presents a promising pathway for converting lignin-derived phenolic compounds.

2.
ACS Appl Mater Interfaces ; 16(29): 37656-37668, 2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-38987704

RESUMEN

Rheumatoid arthritis (RA), an immune-mediated inflammatory disease, is characterized by a large number of infiltrated immune cells and abnormally elevated reactive oxygen species (ROS) in the joint. Various proinflammatory factors secreted by macrophages and the elevated ROS by inflammatory cells are deeply intertwined and together contribute to joint damage. Targeted and sustained anti-inflammation and antioxidation strategies are needed for RA treatment. To alleviate the oxidative stress and target the source of inflammatory cytokines, we developed a thermosensitive injectable hydrogel, Dex-DSLip/Cro@Gel, to coordinate the targeted anti-inflammatory and antioxidation effects. Within the injectable gel, dexamethasone (Dex)-loaded liposomes (Dex-DSLip), modified with dextran sulfate (DS), target macrophages via interaction with scavenger receptor A (SR-A). Simultaneously, crocin I (Cro) is loaded in the gel with a high loading capacity. The porous structure of Dex-DSLip/Cro@Gel successfully prolongs the retention time of both drugs and sustains the release of Dex and Cro. After intra-articular injection of Dex-DSLip/Cro@Gel in RA rats, the expression of inflammatory factors in the ankle joints was significantly reduced. Joint erythema and bone erosion were markedly alleviated. Through the synergistic effects of Dex and Cro, Dex-DSLip/Cro@Gel demonstrates targeted anti-inflammatory and antioxidation effects as well as mitigated bone erosion and long-term therapeutic effects for RA. This thermosensitive injectable nanocomposite hydrogel synergizes anti-inflammatory and antioxidation effects and targets the microenvironment in the joint, offering a new approach for RA treatment.


Asunto(s)
Antioxidantes , Artritis Reumatoide , Macrófagos , Nanocompuestos , Antioxidantes/administración & dosificación , Antioxidantes/química , Antioxidantes/farmacología , Nanocompuestos/química , Hidrogeles/química , Artritis Reumatoide/tratamiento farmacológico , Inyecciones , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Sulfato de Dextran/química , Carotenoides/administración & dosificación , Carotenoides/química , Carotenoides/farmacología , Carotenoides/uso terapéutico , Especies Reactivas de Oxígeno/metabolismo , Humanos , Animales , Ratones , Ratas , Células Cultivadas , Osteoclastos/citología , Osteoclastos/efectos de los fármacos , Osteoclastos/metabolismo , Osteogénesis , Masculino , Ratones Endogámicos C57BL , Ratas Sprague-Dawley , Antiinflamatorios/administración & dosificación , Antiinflamatorios/química , Antiinflamatorios/farmacología
3.
Chem Asian J ; 19(16): e202400217, 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-38752326

RESUMEN

With increasing global emphasis on environmental sustainability, the reliance on traditional energy sources such as coal, natural gas, and oil are encountering significant challenges. H2, known for its high energy content and pollution-free usage, emerges as a promising alternative. However, despite the great potential of H2, approximately 95 % of hydrogen production still depends on non-renewable resources. Hence, the shift towards producing H2 from renewable sources, particularly through methods like steam reforming of methanol - a renewable resource - represents a beacon of hope for advancing sustainable energy practices. This review comprehensively examines recent advancements in efficient H2 production using Ni-based catalysts in methanol steam reforming (MSR) and proposes the future prospects. Firstly, the fundamental principles of MSR technology and the significance in clean energy generation are elucidated. Subsequently, the design, synthesis techniques, and optimization strategies for enhancing the catalytic performance of Ni-based catalysts are discussed. Through the analysis of various catalyst compositions, structural adjustments, surface active sites, and modification methods, the review uncovers effective approaches for boosting the activity and durability of MSR reactions. Moreover, the review investigates the causes of deactivation in Ni-based catalysts during MSR reactions and proposes strategies for extending catalyst lifespan through fine design and optimization of operation parameters. Lastly, this review outlines the current research challenges and anticipates the future trends and potential applications of Ni-based catalysts in MSR hydrogen production. By offering a comprehensive critical analysis, this review serves as a valuable reference to enhance MSR hydrogen production efficiency and catalyst performance.

4.
Rev Sci Instrum ; 94(8)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38065130

RESUMEN

The dynamic measurement of surface deformation with an axisymmetric profile at nanometer- to micrometer-scale is of great interest in understanding micromechanical and thermophysical dynamics. We propose a carrier optical vortex interferometer (COVI) to measure such surface deformation dynamically by segmentation demodulation of the petal-like interferogram that is produced by the coaxial superposition of conjugated p-radial order Laguerre-Gaussian beams. Specifically, a rotating chopper placed at the exit of the interferometer introduces a carrier frequency in the absence of surface deformation. A camera placed behind the chopper uses a multi-ring segmentation detection scheme to produce a Doppler shift relative to the carrier frequency at the radius of each ring in the presence of axisymmetric surface deformation. Locating the Doppler shifts gives the surface deformation velocities at those radii. Thus, the dynamic surface deformation profile can be obtained by integrating the velocities over time. We reveal the basic principles of the carrier frequency and the Doppler shifts in the COVI theoretically. As a proof-of-concept, an external force-induced axisymmetric mechanical surface deformation is measured dynamically to demonstrate the validity of the COVI. The results show that the measurement error of the surface deformation velocity is within (-2.1, 1.1 nm/s) for the velocity ranging from 20 to 86 nm/s. The lower limit of the measurable velocity can reach 20 nm/s. The measurement error of the surface deformation profile is less than 2.5 nm for the amplitude of the surface deformation of 500 nm.

5.
Opt Lett ; 48(8): 2018-2021, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-37058631

RESUMEN

A vortex beam interferometer based on Doppler frequency shift is proposed to retrieve the dynamic non-uniform phase shift from the petal-like fringes produced by the coaxial superposition of high-order conjugated Laguerre-Gaussian modes. Unlike the uniform phase shift measurement in which the petal-like fringes rotate as a whole, the fringes due to the dynamic non-uniform phase shift rotate at different angles at different radii, resulting in highly twisted and stretched petals; this hinders rotation angle identification and phase retrieval via image morphological operation. To address the problem, a rotating chopper combined with a collecting lens and a point photodetector are placed at the exit of the vortex interferometer to introduce a carrier frequency in the absence of the phase shift. Once the phase starts to shift non-uniformly, the petals at different radii generate different Doppler frequency shifts, owing to their different rotation velocities. Thus, identification of spectral peaks near the carrier frequency immediately indicates the rotation velocities of the petals and the phase shifts at those radii. The results verified a relative error of phase shift measurement to be within 2.2% at the surface deformation velocities of 1, 0.5, and 0.2 µm/s. The method manifests itself to have potential in exploiting mechanical and thermophysical dynamics from the nanometer to micrometer scale.

6.
J Orthop Surg Res ; 17(1): 459, 2022 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-36266690

RESUMEN

BACKGROUND: The arthroscopic Broström-Gould procedure (ABG) gained particular attention among clinicians and researchers due to its high rate of satisfactory results. There is a lack of evidence regarding the differences in clinical outcomes for the various suture techniques. The purpose of this study was to compare the differences in clinical effect in patients treated with one-anchor modified Mason-Allen suture or two-anchor horizontal mattress suture for chronic ankle instability (CAI). METHODS: This retrospective cohort study examined CAI patients who underwent either one-anchor modified Mason-Allen suture or two-anchor horizontal mattress suture ABG between January 2018 and January 2020. Patients were divided into two groups based on the suture knot type used and the associated number of anchors. The operative time, surgical cost, Visual Analog Scale (VAS), American Orthopedic Foot & Ankle Society (AOFAS) Score, Karlsson Ankle Functional Score (KAFS), the rate of return to sports, complications, and measured biomechanical strength using standardized equipment were compared between groups. RESULTS: Sixty-four CAI patients were included (one-anchor modified Mason-Allen suture group n = 30, two-anchor horizontal mattress suture group n = 34). Compared to the two-anchor horizontal mattress suture group, the one-anchor modified Mason-Allen suture group had significantly shorter operative time (p < .001) and lower surgical cost (p < .001). There were no postoperative complications in the two groups, and no significant differences in the VAS, AOFAS, KAFS, and rate of return to sports in postoperative follow-up between the two groups at 1 and 2 years after surgery. There was no statistically significant difference in biomechanical strength anterior drawer test displacement (p > .05) between the one-anchor modified Mason-Allen suture and two-anchor horizontal mattress suture at 2 years after surgery. CONCLUSION: ABG using a one-anchor modified Mason-Allen suture showed comparable clinical results to a two-anchor horizontal mattress suture in the treatment of CAI at intermediate-term follow-up time. However, one-anchor modified Mason-Allen suture may be a faster, simpler, cost-effective substitute technology. LEVEL OF EVIDENCE: Level III, comparative study.


Asunto(s)
Inestabilidad de la Articulación , Ligamentos Laterales del Tobillo , Humanos , Anclas para Sutura , Tobillo/cirugía , Estudios Retrospectivos , Artroscopía/métodos , Inestabilidad de la Articulación/cirugía , Articulación del Tobillo/cirugía , Técnicas de Sutura , Suturas , Ligamentos Laterales del Tobillo/cirugía
7.
Rev Sci Instrum ; 93(8): 083703, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-36050082

RESUMEN

Dark-field detection has long been used to identify micron/submicron-sized surface defects benefiting from the broadening effect of the actual defect size caused by light scattering. However, the back-side scattering of a transmissive optical slab is inevitably confused with the front-side scattering phenomenon, resulting in deterioration of the signal-to-noise ratio (SNR) of the scattering signal and false alarms for real defect detection. To this end, a confocal line-scan laser scattering probe equipped with optical sectioning ability is proposed to separate the back-side scattering from the front-side scattering. The optical sectioning ability is realized through a confocal light scattering collector, which overcomes the restriction imposed on the numerical aperture (NA) and the field of view (FOV), reaching an FOV length of 90 mm and NA of 0.69. The line-scan principle of the probe protects itself from crosstalk because it produces only a laser spot on the tested surface in an instant. Experimental results verified that the probe has a line-scan length of 90 mm with a uniformity better than 98%, an rms electronic noise of 3.4 mV, and an rms background noise of 6.4 mV with laser on. The probe can reject the false back-side scattering light for a 2 mm thick fused silica slab at 17.1 dB SNR and operate at a high imaging efficiency of 720 mm2/s with a minimum detectability limit of 1.4 µm at 12 dB SNR. This work put forward an effective method with great application value for submicron-sized defect detection in transmissive optics.

8.
Front Chem ; 9: 712453, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34368083

RESUMEN

Pickering emulsion offers a promising platform for conducting interfacial reactions between immiscible reagents; it is particularly suitable for hydrogen production by photoreforming of non-water soluble biomass liquid and water. Herein, Pt-promoted (001)-facet-dominated anatase TiO2 nanosheets were synthesized by a hydrothermal route associated with microfluidic technology for high activity and metal dispersion, and selective surface modification was carried out for preparing Janus particles. Photoreforming hydrogen production through n-octanol and water that formed O/W microemulsion with an average diameter of 540 µm was achieved to obtain amphiphilic catalyst. The as-prepared 2D Janus-type catalysts exhibited remarkably stable emulsification performance as well as photocatalytic activity. This finding indicates that triethoxyfluorosilane had negligible impact on the catalytic performance, yet provided a remarkable benefit to large specific surface area at microemulsion interface, thereby enhancing the H2 yield up to 2003 µmol/g. The cyclic experiments indicate that the decrease in cyclic performance was more likely to be caused by the coalescence of the microemulsion rather than the decrease in catalytic activity, and the microemulsion could be easily recovered by simply hand shaking to more than 96% of the initial performance.

9.
Heart Rhythm ; 17(2): 332-340, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31513946

RESUMEN

BACKGROUND: Ondansetron, a widely prescribed antiemetic, has been implicated in drug-induced long QT syndrome. Recent patch clamp experiments have shown that ondansetron inhibits the apamin-sensitive small conductance calcium-activated potassium current (IKAS). OBJECTIVE: The purpose of this study was to determine whether ondansetron causes action potential duration (APD) prolongation by IKAS inhibition. METHODS: Optical mapping was performed in rabbit hearts with pacing-induced heart failure (HF) and in normal hearts before and after ondansetron (100 nM) infusion. APD at 80% repolarization (APD80) and arrhythmia inducibility were determined. Additional studies with ondansetron were performed in normal hearts perfused with hypokalemic Tyrode's (2.4 mM) solution before or after apamin administration. RESULTS: The corrected QT interval in HF was 326 ms (95% confidence interval [CI] 306-347 ms) at baseline and 364 ms (95% CI 351-378 ms) after ondansetron infusion (P < .001). Ondansetron significantly prolonged APD80 in the HF group and promoted early afterdepolarizations, steepened the APD restitution curve, and increased ventricular vulnerability. Ventricular fibrillation was not inducible in HF ventricles at baseline, but after ondansetron infusion, ventricular fibrillation was induced in 5 of the 7 ventricles (P = .021). In hypokalemia, apamin prolonged APD80 from 163 ms (95% CI 146-180 ms) to 180 ms (95% CI 156-204 ms) (P = .018). Subsequent administration of ondansetron failed to further prolong APD80 (180 ms [95% CI 156-204 ms] vs 179 ms [95% CI 165-194 ms]; P = .789). The results were similar when ondansetron was administered first, followed by apamin. CONCLUSION: Ondansetron is a specific IKAS blocker at therapeutic concentrations. Ondansetron may prolong the QT interval in HF by inhibiting small conductance calcium-activated potassium channels, which increases the vulnerability to ventricular arrhythmias.


Asunto(s)
Estimulación Cardíaca Artificial , Insuficiencia Cardíaca/terapia , Ventrículos Cardíacos/fisiopatología , Ondansetrón/farmacología , Fibrilación Ventricular/complicaciones , Potenciales de Acción , Animales , Apamina/farmacología , Modelos Animales de Enfermedad , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/fisiopatología , Técnicas de Placa-Clamp , Conejos , Antagonistas de la Serotonina/farmacología , Canales de Potasio de Pequeña Conductancia Activados por el Calcio , Fibrilación Ventricular/fisiopatología
10.
Int J Chron Obstruct Pulmon Dis ; 13: 1949-1963, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29942127

RESUMEN

Background: Inhaled medication is central to the treatment of COPD. Various types of inhaler devices, which directly deliver medication to the lung, have been developed. However, patients often exhibit incorrect techniques of inhaler usage. Effectiveness of therapy may be affected by the ease of device usage, size, convenience of use, durability, clarity of instructions and device preferences of patients. This study compares the satisfaction and preference, as well as error occurrence, with the use of Genuair®, Ellipta™ and Breezhaler™ by healthy subjects in Hong Kong. Subjects and methods: One hundred and thirty healthy Hong Kong Chinese subjects aged ≥40 years without a previous diagnosis of COPD and asthma and with no experience of using dry powder inhalers (DPIs) were recruited. Subjects learned to use the three DPIs by initially reading the instructions and then observing a demonstration with verbal explanation. The number of errors committed was evaluated. Subjects also completed a questionnaire to indicate their satisfaction and preference. Results: The satisfaction score of comfort for Breezhaler was significantly higher than that for Ellipta (p≤0.05), while the satisfaction score on confidence to have inhaled the entire dose was highest for Genuair compared with Ellipta (p≤0.0001) or Breezhaler (p≤0.05). The overall satisfaction score was significantly higher for Genuair than Ellipta (p≤0.05) or Breezhaler (p≤0.01). After reading the instructions, the highest number of subjects committing one or more critical errors was with Breezhaler (97) followed by Genuair (70) and then Ellipta (33). Demonstration reduced the number of critical errors made by subjects for each DPI to one third or lower. Conclusion: Breezhaler seemed to be more comfortable and easy to carry, but users made less critical errors when using Ellipta after reading the instructions only. Genuair provided the clearest indication of correct dose preparation and inhalation.


Asunto(s)
Asma/tratamiento farmacológico , Inhaladores de Polvo Seco , Errores de Medicación/estadística & datos numéricos , Prioridad del Paciente/psicología , Satisfacción del Paciente , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Administración por Inhalación , Adulto , Anciano , Anciano de 80 o más Años , Asma/psicología , Inhaladores de Polvo Seco/clasificación , Inhaladores de Polvo Seco/psicología , Diseño de Equipo , Femenino , Hong Kong , Humanos , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/psicología
11.
Heart Rhythm ; 15(8): 1242-1251, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29654853

RESUMEN

BACKGROUND: Stellate ganglion nerve activity (SGNA) precedes paroxysmal atrial tachyarrhythmia (PAT) episodes in dogs with intermittent rapid left atrial (LA) pacing. The left dorsal branch of the thoracic nerve (LDTN) contains sympathetic nerves originating from the stellate ganglia. OBJECTIVE: The purpose of this study was to test the hypothesis that high-frequency electrical stimulation of the LDTN can cause stellate ganglia damage and suppress PATs. METHODS: We performed long-term LDTN stimulation in 6 dogs with and 2 dogs without intermittent rapid LA pacing while monitoring SGNA. RESULTS: LDTN stimulation reduced average SGNA from 4.36 µV (95% confidence interval [CI] 4.10-4.62 µV) at baseline to 3.22 µV (95% CI 3.04-3.40 µV) after 2 weeks (P = .028) and completely suppressed all PAT episodes in all dogs studied. Tyrosine hydroxylase staining showed large damaged regions in both stellate ganglia, with increased percentages of tyrosine hydroxylase-negative cells. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that 23.36% (95% CI 18.74%-27.98%) of ganglion cells in the left stellate ganglia and 11.15% (95% CI 9.34%-12.96%) ganglion cells in the right stellate ganglia were positive, indicating extensive cell death. A reduction of both SGNA and heart rate was also observed in dogs with LDTN stimulation but without rapid LA pacing. Histological studies in the 2 dogs without intermittent rapid LA pacing confirmed the presence of extensive stellate ganglia damage, along with a high percentage of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells. CONCLUSION: LDTN stimulation damages both left and right stellate ganglia, reduces left SGNA, and is antiarrhythmic in this canine model of PAT.


Asunto(s)
Fibrilación Atrial/terapia , Terapia por Estimulación Eléctrica/métodos , Atrios Cardíacos/fisiopatología , Ganglio Estrellado/fisiopatología , Taquicardia Paroxística/terapia , Nervios Torácicos/fisiopatología , Animales , Fibrilación Atrial/fisiopatología , Modelos Animales de Enfermedad , Perros , Electrocardiografía , Sistema Nervioso Simpático/fisiopatología , Taquicardia Paroxística/fisiopatología
12.
Heart Rhythm ; 15(5): 761-769, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29325977

RESUMEN

BACKGROUND: Apamin-sensitive small conductance calcium-activated K current (IKAS) is up-regulated during ventricular pacing and masks short-term cardiac memory (CM). OBJECTIVE: The purpose of this study was to determine the role of IKAS in long-term CM. METHODS: CM was created with 3-5 weeks of ventricular pacing and defined by a flat or inverted T wave off pacing. Epicardial optical mapping was performed in both paced and normal ventricles. Action potential duration (APD80) was determined during right atrial pacing. Ventricular stability was tested before and after IKAS blockade. Four paced hearts and 4 normal hearts were used for western blotting and histology. RESULTS: There were no significant differences in either echocardiographic parameters or fibrosis levels between groups. Apamin induced more APD80 prolongation in CM than in normal ventricles (mean [95% confidence interval]: 9.6% [8.8%-10.5%] vs 3.1% [1.9%-4.3%]; P <.001). Apamin significantly lengthened APD80 in the CM model at late activation sites, indicating significant IKAS up-regulation at those sites. The CM model also had altered Ca2+ handling, with the 50% Ca2+ transient duration and amplitude increased at distal sites compared to a proximal site (near the pacing site). After apamin, the CM model had increased ventricular fibrillation (VF) inducibility (paced vs control: 33/40 (82.5%) vs 7/20 (35%); P <.001) and longer VF durations (124 vs 26 seconds; P <.001). CONCLUSION: Chronic ventricular pacing increases Ca2+ transients at late activation sites, which activates IKAS to maintain repolarization reserve. IKAS blockade increases VF vulnerability in chronically paced rabbit ventricles.


Asunto(s)
Apamina/farmacología , Ventrículos Cardíacos/fisiopatología , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/genética , Fibrilación Ventricular/fisiopatología , Potenciales de Acción/efectos de los fármacos , Animales , Western Blotting , Modelos Animales de Enfermedad , Ecocardiografía , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/efectos de los fármacos , Inmunohistoquímica , Técnicas de Placa-Clamp , Reacción en Cadena de la Polimerasa , ARN/genética , Conejos , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/metabolismo , Fibrilación Ventricular/diagnóstico , Fibrilación Ventricular/genética
13.
G3 (Bethesda) ; 8(2): 377-383, 2018 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-29208649

RESUMEN

The Hulunbuir short-tailed sheep (Ovis aries) is a breed native to China, in which the short-tail phenotype is the result of artificial and natural selection favoring a specific set of genetic mutations. Here, we analyzed the genetic differences between short-tail and normal-tail phenotypes at the genomic level. Selection signals were identified in genome-wide sequences. From 16 sheep, we identified 72,101,346 single nucleotide polymorphisms. Selection signals were detected based on the fixation index and heterozygosity. Seven genomic regions under putative selection were identified, and these regions contained nine genes. Among these genes, T was the strongest candidate as T is related to vertebral development. In T, a nonsynonymous mutation at c.G334T resulted in p.G112W substitution. We inferred that the c.G334T mutation in T leads to functional changes in Brachyury-encoded by this gene-resulting in the short-tail phenotype. Our findings provide a valuable insight into the development of the short-tail phenotype in sheep and other short-tailed animals.


Asunto(s)
Proteínas Fetales/genética , Polimorfismo de Nucleótido Simple , Proteínas de Dominio T Box/genética , Cola (estructura animal)/metabolismo , Secuenciación Completa del Genoma/métodos , Animales , Genotipo , Mutación , Fenotipo , Selección Genética , Ovinos , Cola (estructura animal)/crecimiento & desarrollo
14.
Opt Lett ; 42(4): 727-730, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-28198850

RESUMEN

In this Letter, we present the design of a simple signal interrogator for optical fiber-based white light Fabry-Perot (F-P) interferometers. With the hardware being composed of only a flat fused silica wafer and a CCD camera, this interrogator translates the spectral interference into a spatial interference pattern, and then demodulates the F-P cavity length with the use of a relatively simple demodulation algorithm. The concept is demonstrated experimentally in a fiber optic sensor with a sapphire wafer as the F-P cavity.

15.
Nucleic Acids Res ; 45(1): 115-126, 2017 01 09.
Artículo en Inglés | MEDLINE | ID: mdl-27651453

RESUMEN

Neuroglobin (NGB) is predominantly expressed in the brain and retina. Studies suggest that NGB exerts protective effects to neuronal cells and is implicated in reducing the severity of stroke and Alzheimer's disease. However, little is known about the mechanisms which regulate the cell type-specific expression of the gene. In this study, we hypothesized that distal regulatory elements (DREs) are involved in optimal expression of the NGB gene. By chromosome conformation capture we identified two novel DREs located -70 kb upstream and +100 kb downstream from the NGB gene. ENCODE database showed the presence of DNaseI hypersensitive and transcription factors binding sites in these regions. Further analyses using luciferase reporters and chromatin immunoprecipitation suggested that the -70 kb region upstream of the NGB gene contained a neuronal-specific enhancer and GATA transcription factor binding sites. Knockdown of GATA-2 caused NGB expression to drop dramatically, indicating GATA-2 as an essential transcription factor for the activation of NGB expression. The crucial role of the DRE in NGB expression activation was further confirmed by the drop in NGB level after CRISPR-mediated deletion of the DRE. Taken together, we show that the NGB gene is regulated by a cell type-specific loop formed between its promoter and the novel DRE.


Asunto(s)
Cromosomas Humanos Par 14/química , Factor de Transcripción GATA2/genética , Globinas/genética , Proteínas del Tejido Nervioso/genética , Neuronas/metabolismo , Elementos Reguladores de la Transcripción , Sitios de Unión , Sistemas CRISPR-Cas , Línea Celular Tumoral , Desoxirribonucleasa I/genética , Desoxirribonucleasa I/metabolismo , Factor de Transcripción GATA2/metabolismo , Edición Génica , Regulación de la Expresión Génica , Genes Reporteros , Globinas/antagonistas & inhibidores , Globinas/metabolismo , Células HeLa , Humanos , Células K562 , Luciferasas/genética , Luciferasas/metabolismo , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/metabolismo , Neuroglobina , Neuronas/citología , Especificidad de Órganos , Unión Proteica , ARN Guía de Kinetoplastida/genética , ARN Guía de Kinetoplastida/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal
16.
Waste Manag ; 50: 105-12, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26876776

RESUMEN

This work compares the performance of stabilizing Pb by Sodium sulfide (Na2S), Sodium phosphate (Na3PO4), thiourea (H2NCSNH2), and mercapto functionalized dendrimer (TEPA-SNa) in MSWI fly ash, including leaching toxicity analysis and leaching behavior analysis, as a function of pH. The leaching toxicity in fly ash indicated that leaching value of Pb stabilized by Na2S, Na3PO4, and H2NCSNH2 has remained higher than the limit value (0.25mg/L) with a dosage of 10%. However, the leaching value associated with TEPA-SNa approaches zero at a dosage of 3%. The effective leaching test results showed the leaching amount of Pb stabilized by TEPA-SNa with a dosage of 3% to be 3.58 mg/kg less than the maximum allowable amount of leaching (5mg/kg), but the amount of Pb leached by Na2S, Na3PO4, and H2NCSNH2 was much higher than 5mg/kg. The leaching behavior of Pb as a function of pH showed that the leaching concentration of Pb stabilized by TEPA-SNa can approach zero at a dosage of 5% no matter how the pH changes. In summary, TEPA-SNa can interact with Pb(2+) in the acid-base environment and effectively immobilize Pb(2+) in fly ash in the long term.


Asunto(s)
Quelantes/química , Ceniza del Carbón/análisis , Dendrímeros/química , Plomo/química , Compuestos de Sulfhidrilo/química , Incineración , Fosfatos/química , Sulfuros/química , Tiourea/química
17.
Opt Lett ; 41(2): 195-8, 2016 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-26766672

RESUMEN

A sourceless sapphire fiber extrinsic Fabry-Perot interferometer for ultrahigh temperature sensing is developed. A sapphire wafer is mounted on the tip of a sapphire fiber as the Fabry-Perot cavity. The interference signal is generated by the thermal radiation that transmits through the wafer and is guided to a spectrometer by a sapphire and then a silica fiber. The entire sensor system is compact and low cost. The sensor was experimentally tested up to 1593°C, and a resolution around 1°C was achieved.

18.
Opt Lett ; 40(9): 2041-4, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25927779

RESUMEN

Anti-Stokes Raman scattering in sapphire fiber has been observed for the first time. Temperature dependence of Raman peaks' intensity, frequency shift, and linewidth were also measured. Three anti-Stokes Raman peaks were observed at temperatures higher than 300°C in a 0.72-m-long sapphire fiber excited by a second-harmonic Nd YAG laser. The intensity of anti-Stokes peaks are comparable to that of Stokes peaks when the temperature increases to 1033°C. We foresee the combination of sapphire fiber Stokes and anti-Stokes measurement in use as a mechanism for ultrahigh temperature sensing.

19.
Nat Commun ; 6: 6680, 2015 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-25813084

RESUMEN

Magnetoelectric composite thin films hold substantial promise for applications in novel multifunctional devices. However, there are presently shortcomings for both the extensively studied bilayer epitaxial (2-2) and vertically architectured nanocomposite (1-3) film systems, restricting their applications. Here we design a novel growth strategy to fabricate an architectured nanocomposite heterostructure with magnetic quasiparticles (0) embedded in a ferroelectric film matrix (3) by alternately growing (2-2) and (1-3) layers within the film. The new heteroepitaxial films not only overcome the clamping effect from substrate, but also significantly suppress the leakage current paths through the ferromagnetic phase. We demonstrate, by focusing on switching characteristics of the piezoresponse, that the heterostructure shows magnetic field dependence of piezoelectricity due to the improved coupling enabled by good connectivity amongst the piezoelectric and magnetostrictive phases. This new architectured magnetoelectric heterostructures may open a new avenue for applications of magnetoelectric films in micro-devices.

20.
PLoS One ; 9(5): e96404, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24788721

RESUMEN

Zearalenone (ZEA), a mycoestrogen produced by Fusarium fungal species, is mainly found in cereal crops such as maize, wheat and barley. Although ZEA has been reported to be present in air, little is known about the health risk or the molecular basis of action when lung cells are exposed to ZEA. As ZEA has a similar structure to estrogen, its potential risk as an endocrine disrupting chemical (EDC) has thus aroused both environmental and public health concerns. The purpose of this study is to identify the responses and underlying molecular changes that occur when human bronchial epithelial BEAS-2B cells are exposed to ZEA. Differential gene expression profiles were identified in cells that were treated with 40 µM ZEA for 6 h and 24 h by high-throughput microarray analysis using Affymetrix Human Gene 2.0 GeneChip. The array results showed that after ZEA treatment, 262 genes at 6 h and 1073 genes at 24 h were involved in the differential regulation. Pathway analysis revealed that diverse cellular processes were affected when lung cells were exposed to ZEA resulting in impaired response to DNA damage, cell cycle arrest, down-regulation of inflammatory responses and alterations of epigenetic marks. Results of further experiments indicated that 40 µM ZEA decreased cell viability, induced apoptosis and promoted reactive oxygen species (ROS) generation in a time-dependent manner. Immuno-suppressive effects of ZEA were further revealed through the suppression of lipopolysaccharide (LPS)-induced expression of pro-inflammatory cytokines (IL-6, IL-8 and IL-1ß). Interestingly, the level of global DNA methylation was markedly decreased after 24 h exposure to ZEA. Collectively, these observations suggested that a broad range of toxic effects are elicited by ZEA. Particularly, ROS may play a pivotal role in ZEA-induced cell death. These adverse effects observed in lung cells suggest that exposure to ZEA may increase susceptibility of lung cells to diseases and required further investigations.


Asunto(s)
Bronquios/citología , Células Epiteliales/efectos de los fármacos , Transcriptoma/efectos de los fármacos , Zearalenona/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/genética , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Línea Celular , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Células Epiteliales/metabolismo , Estrógenos no Esteroides/farmacología , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Factores de Tiempo , Transcriptoma/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA