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1.
Small ; : e2402355, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38751066

RESUMEN

Engineering the intermetallic nanostructures as an effective bifunctional electrocatalyst for hydrogen and oxygen evolution reactions (HER and OER) is of great interest in green hydrogen production. However, a few non-noble metals act as bifunctional electrocatalysts, exhibiting terrific HER and OER processes reported to date. Herein the intermetallic nickel-antimonide (Ni─Sb) dendritic nanostructure via cost-effective electro-co-deposition method is designed and their bifunctional electrocatalytic property toward HER and OER is unrevealed. The designed Ni─Sb delivers a superior bifunctional activity in 1 m KOH electrolyte, with a shallow overpotential of ≈119 mV at -10 mA for HER and ≈200 mV at 50 mA for OER. The mechanism behind the excellent bifunctional property of Ni─Sb is discussed via "interfacial descriptor" with the aid of Kelvin probe force microscopy (KPFM). This study reveals the rate of electrocatalytic reaction depends on the energy required for electron and proton transfer from the catalyst's surface. It is noteworthy that the assembled Ni─Sb-90 electrolyzer requires only a minuscule cell voltage of ≈1.46 V for water splitting, which is far superior to the art of commercial catalysts.

2.
Arthroscopy ; 2024 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-38925233

RESUMEN

PURPOSE: To investigate the effectiveness of bursal acromial resurfacing (acromiograft) on acromiohumeral distance, subacromial contact area, and pressure in a cadaveric model of massive rotator cuff tear. METHODS: Eight fresh-frozen cadaveric shoulders were tested using a customized shoulder testing system. Humeral head translation, subacromial contact pressure, and the subacromial contact area were evaluated across four conditions: (1) intact shoulder; (2) simulated massive rotator cuff tear; (3) 3-mm acromiograft condition; (4) 6-mm acromiograft condition. The acromiografts were simulated using Teflon and a reported technique. The values were measured at 0°, 20°, and 40° abduction and 0°, 30°, 60°, and 90° external rotation (ER) for each abduction status. RESULTS: Compared with a massive cuff tear, the 6-mm acromiograft significantly reduced the superior translation of the humeral head at all abduction/ER angles (P<0.05). The 3-mm acromiograft also decreased superior translation of the humeral head compared to massive cuff tear, but not all differences were significant. The 3- and 6-mm acromiografts significantly decreased the subacromial contact pressure and increased the subacromial contact area in almost all positions (P<0.05). The 3-mm acromiograft maintained biomechanical properties similar to the intact condition, whereas the 6-mm acromiograft increased the contact area. CONCLUSIONS: This biomechanical study demonstrated that both 3- and 6- mm acromiografts using Teflon in a cadaveric model of a massive cuff tear resulted in recentering of the superiorly migrated humeral head, increased the subacromial contact area, and decreased the subacromial contact pressure. The 3- mm graft was sufficient for achieving the intended therapeutic effects. CLINICAL RELEVANCE: The acromiograft can normalize altered biomechanics and may aid the treatment of massive cuff tears. As grafting the acromion's undersurface is new with limited clinical outcomes, further observation is crucial. Using Teflon instead of ADM allograft for bursal acromial resurfacing could yield different results, requiring careful interpretation.

3.
Artículo en Inglés | MEDLINE | ID: mdl-38242527

RESUMEN

BACKGROUND: The utilization of short humeral stems in reverse total shoulder arthroplasty has gained attention in recent times. However, concerns regarding the risk of misalignment during implant insertion are associated with their use. METHODS: Eight fresh-frozen cadaveric shoulders were prepared for dissection and biomechanical testing. A bespoke humeral implant was fabricated to facilitate assessment of neutral, varus, and valgus alignments using a single stem, and 10° was established as the maximum permissible angle for misalignments. Shift in humerus position and changes in deltoid length attributable to misalignments relative to the neutral position were evaluated using a Microscribe 3DLx system. The impingement-free range of motion, encompassing abduction, adduction, internal rotation, and external rotation (ER), was gauged using a digital goniometer. The capacity for abduction was evaluated at maximal abduction angles under successive loading on the middle deltoid. A specialized traction system coupled with a force transducer was employed to measure anterior dislocation forces. RESULTS: Relative to the neutral alignment, valgus alignment resulted in a more distal (10.5 ± 2.4 mm) and medial (8.3 ± 2.2 mm) translation of the humeral component, whereas the varus alignment resulted in the humerus shifting more superiorly (11.2 ± 1.3 mm) and laterally (9.9 ± 0.9 mm) at 0° abduction. The valgus alignment exhibited the highest abduction angle than neutral alignment (86.2°, P < .001). Conversely, the varus alignment demonstrated significantly higher adduction (18.4 ± 7.4°, P < .001), internal rotation (68.9 ± 15.0°, P = .014), and ER (45.2 ± 10.5°, P = .002) at 0° abduction compared to the neutral alignments. Anterior dislocation forces were considerably lower (23.8 N) in the varus group compared to the neutral group at 0°ER (P = .047). Additionally, abduction capability was markedly higher in varus alignment at low deltoid loads than the neutral alignment (5N, P = .009; 7.5 N, P = .007). CONCLUSIONS: The varus position enhances rotational range of motion (ROM) but increases instability, while the valgus position does not significantly impact ROM or instability compared to the neutral position.

4.
BMC Plant Biol ; 23(1): 639, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-38082263

RESUMEN

BACKGROUND: Chitosan biopolymer is an emerging non-toxic and biodegradable plant elicitor or bio-stimulant. Chitosan nanoparticles (CSNPs) have been used for the enhancement of plant growth and development. On the other hand, NO is an important signaling molecule that regulates several aspects of plant physiology under normal and stress conditions. Here we report the synthesis, characterization, and use of chitosan-GSNO nanoparticles for improving drought stress tolerance in soybean. RESULTS: The CSGSNONPs released NO gas for a significantly longer period and at a much lower rate as compared to free GSNO indicating that incorporation of GSNO in CSNPs can protect the NO-donor from rapid decomposition and ensure optimal NO release. CS-GSNONPs improved drought tolerance in soybean plants reflected by a significant increase in plant height, biomass, root length, root volume, root surface area, number of root tips, forks, and nodules. Further analyses indicated significantly lower electrolyte leakage, higher proline content, higher catalase, and ascorbate peroxidase activity, and reduction in MDA and H2O2 contents after treatment with 50 µM CS-GSNONPs under drought stress conditions. Quantitative real-time PCR analysis indicated that CS-GSNONPs protected against drought-induced stress by regulating the expression of drought stress-related marker genes such as GmDREB1a, GmP5CS, GmDEFENSIN, and NO-related genes GmGSNOR1 and GmNOX1. CONCLUSIONS: This study highlights the potential of nano-technology-based delivery systems for nitric oxide donors to improve plant growth, and development and protect against stresses.


Asunto(s)
Quitosano , Nanopartículas , Sequías , Resistencia a la Sequía , Glycine max/genética , Peróxido de Hidrógeno/metabolismo , Estrés Fisiológico/genética
5.
Small ; 17(34): e2102971, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34270870

RESUMEN

The filtering device is a vital component of electronic goods that rectifies ripples which occur upon converting alternating current (AC) to direct current (DC) and attenuates high-frequency noise during switching or voltage declines. Classical filtering devices suffer from low performance metrics and are bulky, limiting their use in modern electronic devices. The fabrication process of electrode materials for high-frequency symmetric supercapacitor (HFSSC) is complicated, hindering commercialization. Herein, for the first time, the design of a high-performance stand-alone carbyne film comprised of sp/sp2 -hybridized carbon as an electrode for AC filtering under a wide frequency range is reported. The carbyne film as HFSSC shows the ideal capacitive behavior at ultrahigh scan rate of 10 000 V s-1 with excellent linearity which is top among the reported AC line filter capacitor. The carbyne HFSSC exhibits a high energy density of 703.25 µF V2  cm-2 at 120 Hz, which is superior to that of current commercial electrolytic filters and many reported AC line supercapacitors. As a proof of concept, a carbyne device is implemented in a real time AC to DC adaptor that demonstrates excellent filtering performance at high frequencies.

6.
Molecules ; 25(17)2020 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-32887320

RESUMEN

Double perovskites have been extensively studied in materials chemistry due to their excellent properties and novel features attributed to the coexistence of ferro/ferri/antiferro-magnetic ground state and semiconductor band gap within the same material. Double perovskites with Sr2NiMO6 (M = Te, W) structure type have been synthesized using simple, non-toxic and costless aqueous citrate sol-gel route. The reaction yielded phase-pure nanocrystalline powders of two compounds: Sr2NiWO6 (SNWO) and Sr2NiTeO6 (SNTO). According to the Rietveld refinement of powder X-ray diffraction data at room temperature, Sr2NiWO6 is tetragonal (I4/m) and Sr2NiTeO6 is monoclinic (C12/m1), with average crystallite sizes of 49 and 77 nm, respectively. Structural studies have been additionally performed by Raman spectroscopy revealing optical phonons typical for vibrations of Te6+/W6+O6 octahedra. Both SNTO and SNWO possess high values of dielectric constants (341 and 308, respectively) with low dielectric loss (0.06 for SNWO) at a frequency of 1 kHz. These values decrease exponentially with the increase of frequency to 1000 kHz, with the dielectric constant being around 260 for both compounds and dielectric loss being 0.01 for SNWO and 0.04 for SNTO. The Nyquist plot for both samples confirms the non-Debye type of relaxation behavior and the dominance of shorter-range movement of charge carriers. Magnetic studies of both compounds revealed antiferromagnetic behavior, with Néel temperature (TN) being 57 K for SNWO and 35 K for SNTO.


Asunto(s)
Compuestos de Calcio/química , Imanes/química , Nanopartículas/química , Óxidos/química , Titanio/química , Compuestos de Calcio/síntesis química , Cristalización , Espectroscopía Dieléctrica , Modelos Moleculares , Óxidos/síntesis química , Espectrometría por Rayos X , Espectrometría Raman , Temperatura , Difracción de Rayos X
7.
Trop Med Int Health ; 24(4): 421-431, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30663180

RESUMEN

OBJECTIVE: To present results of the first national anti-tuberculosis (TB) drug resistance survey conducted in Lao PDR between May 2016 and August 2017 to determine the prevalence of resistance to first-line anti-TB drugs among new and previously treated pulmonary TB cases in the country. METHODS: Patients with sputum smear-positive pulmonary TB were enrolled from 42 TB laboratories distributed in 40 clusters throughout the country. Survey sites were selected using probability-proportional-to-size sampling among all diagnostic centres in the country. In addition to smear microscopy, all patients underwent Xpert MTB/RIF testing and those found positive to Mycobacterium tuberculosis underwent sputum culture and drug susceptibility testing using the proportion method on solid Löwenstein-Jensen medium. RESULTS: Among 1006 eligible patients, 946 sputum smear-positive and Xpert MTB/RIF positive (Mycobacterium tuberculosis detected) patients were included in the survey, comprising 897 new and 49 previously treated TB cases. The prevalence of rifampicin-resistant TB was 1.2% (95% CI: 0.5-2.0%, n = 11/897) among new cases and 4.1% (95% CI: 0-9.6%, n = 2/49) among previously treated cases. Among the 946 TB cases confirmed by Xpert MTB/RIF, phenotypic drug sensitivity testing was available for 820 (776 new and 44 previously treated). The prevalence of multidrug-resistant TB (MDR-TB) was 0.5% (95% CI: 0-1.0%, n = 4/776) among new cases and 2.3% (95% CI: 0-6.7%, n = 1/44) among previously treated cases. No resistance to second-line injectable agents nor to fluoroquinolones was detected among MDR-TB patients. CONCLUSIONS: The first national anti-TB drug resistance survey in Lao PDR demonstrated an encouragingly low prevalence of MDR-TB. The results appear lower than previous WHO estimates, and in line with the routine surveillance based on Xpert MTB/RIF testing (conducted among 50% of presumptive TB patients in 2017). The country should continue to expand its Xpert MTB/RIF network and strive to achieve universal drug susceptibility testing.


OBJECTIF: Présenter les résultats de la première surveillance nationale de la résistance aux médicaments antituberculeux, menée en République Démocratique Populaire (RDP) Lao entre mai 2016 et août 2017 afin de déterminer la prévalence de la résistance aux médicaments antituberculeux de première intention chez les nouveaux cas et les cas déjà traités de tuberculose (TB) pulmonaire dans le pays. MÉTHODES: Les patients atteints de TB pulmonaire à frottis d'expectoration positif ont été recrutés dans 42 laboratoires TB répartis dans 40 groupes à travers tout le pays. Les sites de surveillance ont été sélectionnés sur la base d'un échantillon probabiliste proportionnel à la taille parmi tous les centres de diagnostic du pays. Outre l'examen microscopique des frottis, tous les patients ont subi un test Xpert MTB/RIF et ceux trouvés positifs pour Mycobacterium tuberculosis ont subi une culture d'expectorations et un test de sensibilité aux médicaments en utilisant la méthode des proportions sur un milieu solide de Löwenstein-Jensen. RÉSULTATS: Parmi les 1.006 patients éligibles, 946 patients à frottis positif et Xpert MTB/RIF positif (Mycobacterium tuberculosis détecté) ont été inclus dans la surveillance, comprenant 897 nouveaux cas et 49 cas de TB déjà traités. La prévalence de la TB résistante à la rifampicine était de 1,2% (IC95%: 0,5-2,0%, n = 11/897) chez les nouveaux cas et de 4,1% (IC95%: 0-9,6%, n = 2/49) chez les cas traités. Parmi les 946 cas de TB confirmés par Xpert MTB/RIF, des tests de sensibilité phénotypique aux médicaments étaient disponibles pour 820 (776 nouveaux cas et 44 cas traités antérieurement). La prévalence de la TB multirésistante (TB-MDR) était de 0,5% (IC95%: 0-1,0%, n = 4/776) chez les nouveaux cas et de 2,3% (IC95%: 0 à 6,7%, n = 1/44) parmi les cas précédemment traités. Aucune résistance aux agents injectables de deuxième intention ni aux fluoroquinolones n'a été détectée chez les patients atteints de TB-MDR. CONCLUSIONS: La première surveillance nationale de la résistance aux médicaments antituberculeux menée en RDP Lao a révélé une prévalence rassurante de la TB-MDR. Les résultats apparaissent inférieurs aux estimations précédentes de l'OMS et conformes à la surveillance de routine basée sur le test Xpert MTB/RIF (menée auprès de 50% des patients atteints de TB présumée en 2017). Le pays devrait continuer à élargir son réseau Xpert MTB/RIF et s'efforcer d'atteindre des tests universels de sensibilité aux médicaments.


Asunto(s)
Antibióticos Antituberculosos/uso terapéutico , Farmacorresistencia Bacteriana , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Pulmonar/tratamiento farmacológico , Adolescente , Adulto , Anciano , Antibióticos Antituberculosos/farmacología , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Laos/epidemiología , Masculino , Tamizaje Masivo , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mycobacterium tuberculosis/crecimiento & desarrollo , Prevalencia , Rifampin/farmacología , Rifampin/uso terapéutico , Esputo/microbiología , Encuestas y Cuestionarios , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Tuberculosis Pulmonar/microbiología , Adulto Joven
8.
Small ; 14(11): e1703044, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29377477

RESUMEN

A feasible, morphological influence on photoresponse behavior of ZnO microarchitectures such as microwire (MW), coral-like microstrip (CMS), fibril-like clustered microwire (F-MW) grown by one-step carrier gas/metal catalyst "free" vapor transport technique is reported. Among them, ZnO F-MW exhibits higher photocurrent (IPh ) response, i.e., IPh/ZnO F-MW > IPh/ZnO CMS > IPh/ZnO MW . The unique structural alignment of ZnO F-MW has enhanced the IPh from 14.2 to 186, 221, 290 µA upon various light intensities such as 0 to 6, 11, 17 mW cm-2 at λ405 nm . Herein, the nature of the as-fabricated ZnO photodetector (PD) is also demonstrated modulated by tuning the inner crystals piezoelectric potential through the piezo-phototronic effect. The IPh response of PD decreases monotonically by introducing compressive strain along the length of the device, which is due to the synergistic effect between the induced piezoelectric polarization and photogenerated charge carriers across the metal-semiconductor interface. The current behavior observed at the two interfaces acting as the source (S) and drain (D) is carefully investigated by analyzing the Schottky barrier heights (ΦSB ). This work can pave the way for the development of geometrically modified strain induced performances of PD to promote next generation self-powered optoelectronic integrated devices and switches.

9.
BJU Int ; 122(2): 283-292, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29633507

RESUMEN

OBJECTIVES: To evaluate the efficacy and safety of three dosing schemes of GV1001 in patients with benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: Eligible patients were men aged ≥50 years, with an International Prostate Symptom Score (IPSS) of ≥13, maximum urinary flow rate (Qmax ) of 5-15 mL/s, post-void residual urine volume (PVR) of ≤200 mL, and prostate volume of ≥30 mL. After a 4 week run-in period, patients were randomly assigned to one of three treatment schedules: Group 1, GV1001 0.4 mg, 2-week interval; Group 2, GV1001 0.56 mg, 2-week interval; Group 3, GV1001 0.56 mg, 4-week interval) or placebo (Group 4). The eligible patients were administered GV1001 or placebo, for a total of seven intradermal injections that were administered at 2-week intervals at weeks 0, 2, 4, 6, 8, 10, and 12. Treatment continued for 12 weeks, and efficacy was evaluated at weeks 4, 8, 12, 13, and 16. Safety was evaluated throughout the 16-week period. The primary efficacy variable was change from baseline (CFB) in total IPSS. Secondary endpoints were CFB in Qmax , PVR, prostate volume, International Index of Erectile Function score, plasma testosterone level, dihydrotestosterone level, and prostate-specific antigen level. RESULTS: A total of 161 patients were included (Group 1, n = 41; Groups 2-4, n = 40). Most patients (88.8%) received all planned doses of the study treatment. At week 13, a statistically significant difference in the mean CFB in IPSS was seen in GV1001 treatment Groups 1 and 2 vs the control group for the full analysis population (-3.5 [control] vs -7.2 and -6.8 in Groups 1 and 2, respectively; both P < 0.05). There were also statistically significant differences in CFB at weeks 8, 12, 13, and 16 in treatment Groups 1 and 2 vs control in the per-protocol population. There was a statistically significant reduction in prostate gland volume at week 16 vs control in all treatment groups (0.8 [control] vs -4.6, -2.5, and -4.2 mL in Groups 1-3, respectively; all P < 0.05). There were no statistically significant differences found in other secondary outcome measures. Adverse event (AE) reporting was similar across all four groups. No treatment-emergent AEs were considered to be related to the study drug. CONCLUSIONS: The results indicate that GV1001 was effective and well tolerated, and may provide potential beneficial effects in patients with BPH. Compared with medical therapies that require daily dosing, the convenient dosing regimen of GV1001 may provide greater patient adherence. Further investigation of these observations will require large-scale clinical evaluation.


Asunto(s)
Hormona Liberadora de Gonadotropina/antagonistas & inhibidores , Fragmentos de Péptidos/administración & dosificación , Inhibidores de Fosfodiesterasa 5/administración & dosificación , Hiperplasia Prostática/tratamiento farmacológico , Telomerasa/administración & dosificación , Anciano , Método Doble Ciego , Humanos , Inyecciones Intradérmicas , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Erección Peniana , Fragmentos de Péptidos/efectos adversos , Inhibidores de Fosfodiesterasa 5/efectos adversos , Antígeno Prostático Específico/metabolismo , Hiperplasia Prostática/patología , Telomerasa/efectos adversos , Testosterona/metabolismo , Resultado del Tratamiento
10.
J Nanosci Nanotechnol ; 16(3): 2541-7, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27455667

RESUMEN

In this paper, we report a simple, cost effective and surfactant-free method for synthesizing different morphology of ß-SnWO4 with irregular, spherical, flake-like and leaf-like structures by using sonochemical method followed by calcination. A well dispersed and highly crystalline ß-SnWO4 crystallites with various sizes have been prepared. The samples were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis spectroscopy, particle size and Zeta potential analyser. The SEM images reveal the successful preparation of an irregular, spherical, flake-like and leaf-like structure of ß-SnWO4. The absorption maximum of as-prepared different structures of ß-SnWO4 was observed in visible region. The degradation efficiency was found to be increased in leaf-like structures compared to irregular, spherical and flake-like structures of ß-SnWO4. Further, an enhanced photocatalytic effect was observed in leaf-like ß-SnWO4 nanoparticles while the common oxidants such as peroxomonosulphate (PMS), peroxodisulphate (PDS) and hydrogen peroxide (H2O2) were added. The degradation efficiency of these oxidants was found in the order of PMS > H2O2 > PDS. Generally these oxidants act as electron scavengers. From our experimental results, it is found that maximum efficiency of 93% was achieved when PMS was added. This shows the vital role of common oxidants in photocatalytic characteristics and their future applications in waste-water treatment.


Asunto(s)
Nanopartículas , Oxidantes/química , Procesos Fotoquímicos , Compuestos de Estaño/química , Compuestos de Tungsteno/química , Catálisis , Microscopía Electrónica de Rastreo , Espectrofotometría Ultravioleta , Difracción de Rayos X
11.
Trop Med Int Health ; 20(9): 1146-1154, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25939366

RESUMEN

OBJECTIVE: The objective of the study was to measure the prevalence of bacteriologically confirmed pulmonary tuberculosis (TB) in Lao PDR in 2010-2011. METHOD: A nationwide, multistage cluster-sampled cross-sectional survey was undertaken in 2010-2011. All consenting participants ≥15 years were screened for pulmonary TB with chest X-ray and symptom questionnaire. Two sputum specimens for bacteriological examination by microscopy and culture were collected from those who screened positive. Prevalence was estimated using multiple imputation and inverse probability weighting methods. RESULTS: Of 39 212 eligible participants from 50 clusters, 6290 participants provided at least one sputum sample for smear and culture. There were 237 bacteriologically confirmed pulmonary TB cases, 107 of which were smear-positive. Chest X-ray screening alone identified 230 (97.0%) cases compared with 118 (49.8%) by symptom screening alone. The estimated prevalence of smear-positive and bacteriologically confirmed TB in those ≥15 years was 278 per 100 000 (95%C.I. 199-356) and 595 per 100 000 (95%C.I. 457-733), respectively. Prevalence significantly increased with age and was higher in men than women. CONCLUSIONS: The prevalence of TB in Lao PDR is almost twice as high than previous estimates, with the greatest burden in the older population. Case detection efforts remain the primary goal of the national TB programme with case notifications being very low in comparison with the estimated number of prevalent cases. The survey observed major limitations with the diagnostic strategy of passive (symptom based) case finding that uses only direct smear microscopy for confirmation.

12.
Nanotechnology ; 25(31): 315101, 2014 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-25030310

RESUMEN

The prevention of bacterial infections in the health care environment is paramount to providing better treatment. Covering a susceptible environment with an antimicrobial coating is a successful way to avoid bacterial growth. Research on the preparation of durable antimicrobial coatings is promising for both fundamental surface care and clinical care applications. Herein, we report a facile, efficient, and scalable preparation of MoO3 paint using a cost-effective ball-milling approach. The MoO3 nanoplates (synthesized by thermal decomposition of ammonium heptamolybdate) are used as a pigment and antibacterial activity moiety in alkyd resin binders and other suitable eco-friendly additives in the preparation of paint. Surface morphology, chemical states, bonding nature, and intermolecular interaction between the MoO3 and the alkyd resin were studied using Raman and x-ray photoelectron spectroscopic analysis. The antibacterial properties of a prepared MoO3 nanoplate against various bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae) was determined using the microdilution method. Bacterial strains exposed to an MoO3 paint coated surface exhibit a significant loss of viability in a time-dependent manner. Fundamental modes of antibacterial activities ascribed from a biocompatible and durable MoO3 nanostructure incorporated into an alkyd resin complex are discussed. The obtained experimental findings suggest the potential utility of prepared MoO3-based paint coating for the prevention of health care associated infections.


Asunto(s)
Antibacterianos/farmacología , Molibdeno/farmacología , Nanoestructuras/química , Óxidos/farmacología , Pintura , Bacterias/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos
13.
Adv Sci (Weinh) ; 11(25): e2401073, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38610120

RESUMEN

This study reports the use of Keplerate-type {Mo72Fe30} polyoxometalate (POMs) nanostructures as a bi-functional-electrocatalyst for HER and OER in an alkaline medium with a lower overpotential (135 mV for HER and 264 mV for OER), and excellent electrochemical stability. The bi-functional catalytic properties of {Mo72Fe30} POM are studied using a scanning electrochemical microscope (SECM) via current mapping using substrate generation and tip collection mode. Furthermore, the bipolar nature of the {Mo72Fe30} POM nano-electrocatalysts is studied using the electrochemical gating via simultaneous monitoring of the electrochemical (cell) and electrical ({Mo72Fe30} POM) signals. Next, a prototype water electrolyzer fabricated using {Mo72Fe30} POM electrocatalysts showed they can drive 10 mA cm-2 with a low cell voltage of 1.62 V in lab-scale test conditions. Notably, the {Mo72Fe30} POM electrolyzers' performance assessment based on recommended conditions for industrial aspects shows that they require a very low overpotential of 1.89 V to drive 500 mA cm-2, highlighting their promising candidature toward clean-hydrogen production.

14.
Adv Sci (Weinh) ; 11(15): e2308160, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38342631

RESUMEN

A CoMoS composite is synthesized to combine the benefits of cobalt and molybdenum sulfides as an anodic material for advanced lithium-ion batteries (LIBs). The synthesis is accomplished using a simple two-step hydrothermal method and the resulting CoMoS nanocomposites are subsequently encapsulated in a carbonized polydopamine shell. The synthesis procedure exploited the self-polymerization ability of dopamine to create nitrogen-doped carbon-coated cobalt molybdenum sulfide, denoted as CoMoS@NC. Notably, the de-lithiation capacity of CoMoS and CoMoS@NC is 420 and 709 mAh g⁻1, respectively, even after 100 lithiation/de-lithiation cycles at a current density of 200 mA g⁻1. Furthermore, excellent capacity retention ability is observed for CoMoS@NC as it withstood 600 consecutive lithiation/de-lithiation cycles with 94% capacity retention. Moreover, a LIB full-cell assembly incorporating the CoMoS@NC anode and an NMC-532 cathode is subjected to comprehensive electrochemical and practical tests to evaluate the performance of the anode. In addition, the density functional theory showcases the increased lithium adsorption for CoMoS@NC, supporting the experimental findings. Hence, the use of dopamine as a nitrogen-doped carbon shell enhanced the performance of the CoMoS nanocomposites in experimental and theoretical tests, positioning the material as a strong candidate for LIB anode.

15.
J Nanosci Nanotechnol ; 13(5): 3515-8, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23858891

RESUMEN

In this article, we attempted a study on field effect transport characteristics of graphene flakes. These graphene flakes were exfoliated by mechanical peeling-off technique and the electrical contacts were patterned by photo-lithographic method. Graphene devices have shown better transfer characteristics which was obtained even in low-voltage (< 5 V). Back-gated graphene transistors were patterned on oxidized silicon wafers. A clear n-type to p-type transition at Dirac point and higher electron drain-current modulation in positive back-gate field with current minimum (the Dirac point) were observed at V(GS) = -1.7 V. The carrier mobility was determined from the measured transconductance. The transconductance of the graphene transistors was observed as high as 18.6 microS with a channel length of 68 microm. A maximum electron mobility of 1870 +/- 143 cm2/V x s and hole mobility of 1050 +/- 35 cm2/V x s were achieved at a drain bias 2.1 V which are comparatively higher values among reported for mechanically exfoliated graphene using lithographic method. The fabricated devices also sustained with high-current density for 40 hr in continuous operation without any change in device resistance, which could be applied for robust wiring applications.


Asunto(s)
Grafito/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Semiconductores , Transporte de Electrón , Diseño de Equipo , Análisis de Falla de Equipo , Ensayo de Materiales , Tamaño de la Partícula
16.
J Nanosci Nanotechnol ; 13(5): 3573-6, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23858905

RESUMEN

Here we report the fabrication and characteristics of graphene oxide (GO) field effect transistor gated with piezopotential of ZnO fine wires on a flexible substrate. The FET device consists of GO thin film on the bottom and ZnO piezoelectric fine wire (PFW) on the top. In the FET device the GO serves as a carrier transport channel and ZnO PFW acts as a gate. When the substrate is bent, a piezopotential is generated in the ZnO PFW. The piezopotential created by the strain in the ZnO PFW was used to control the carrier transport in the GO channel. This device demonstrates the application of piezoelectric ZnO PFW for creating the gating effect on the semiconducting performance of GO film.


Asunto(s)
Grafito/química , Sistemas Microelectromecánicos/instrumentación , Nanotubos/química , Nanotubos/ultraestructura , Transistores Electrónicos , Óxido de Zinc/química , Diseño de Equipo , Análisis de Falla de Equipo , Óxidos/química , Tamaño de la Partícula
17.
Adv Sci (Weinh) ; 10(28): e2303918, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37544914

RESUMEN

Soft robotics has developed rapidly in recent years as an emergent research topic, offering new avenues for various industrial and biomedical settings. Despite these advancements, its applicability is limited to locomotion and actuation due to the lack of an adequate charge storage system that can support the robot's sensory system in challenging conditions. Herein, an ultra-flexible, lightweight (≈50 milligrams), and wirelessly rechargeable micro-supercapacitor as an onboard power source for miniaturized soft robots, capable of powering a range of sensory is proposed. The simple and scalable direct laser combustion technique is utilized to fabricate the robust graphene-like carbon micro-supercapacitor (GLC-MSC) electrode. The GLC-MSC demonstrates superior areal capacitance (8.76 mF cm-2 ), and maintains its original capacitance even under extreme actuation frequency (1-30 Hz). As proof of conceptthe authors fabricate a fully integrated magnetic-soft robot that shows outstanding locomotion aptitude and charged wirelessly (up to 2.4 V within 25s), making it an ideal onboard power source for soft robotics.

18.
J Colloid Interface Sci ; 652(Pt A): 845-855, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37625359

RESUMEN

The topochemical preparation of nanostructured materials (NMs) has received significant attention in recent years due to the exceptional electrochemical properties exhibited by the resulting NMs. This work focuses on the preparation of two-dimensional tungsten di-sulfide (WS2) nanostructures through the topochemical conversion of tungsten trioxide (WO3) nanostructures and also evaluates their potential applications as electrode materials for supercapacitors (SCs). The X-ray diffraction and photoelectron studies conducted in this research reveal the conversion of hexagonal WO3 into hexagonal WS2 nanosheets, accompanied by changes in oxidation states. The FE-SEM and HR-TEM studies confirm the formation of WS2 in the sheet-like morphologies with lateral dimensions of 100 × 100 nm. The electrochemical investigation, using techniques such as CV, galvanostatic CD, and EIS, confirmed the presence of intercalation pseudocapacitance in the WS2 electrode, with a higher electrode-specific-capacitance (260 F g-1) than that of WO3 electrode. The WS2 symmetric SC delivered high device capacitance (59.17 F g-1), energy density (8.21 Wh kg-1) and power density (3,750 W kg-1) with better cyclic stability over 5000 cycles. These experimental findings show that the topochemically synthesized WS2as novel supercapacitor electrodes might be useful for the advancement of future-generation energy storage devices.

19.
ACS Nano ; 17(12): 11087-11219, 2023 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-37219021

RESUMEN

Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade.

20.
J Nanosci Nanotechnol ; 12(11): 8522-5, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23421239

RESUMEN

In this paper, we report highly stable and bipolar resistive switching effects of Ag/Graphene oxide thinfilm/Ag devices. The graphene-oxide (GO) thinfilms were prepared on Ag/SiO2/Si substrates by spin-coating technique. The Ag/GO/Ag devices showed a steady and bipolar resistive switching characteristic. The resistance switching from low resistance state (LRS) and high resistance state (HRS) with the resistance ratio of HRS to LRS of about 10 which was attained at a voltage bias of 0.1 V. Based on the filamentary conduction model, the dominant conduction mechanism of switching effect was well explained. Our results show GO can be a promising candidate for future development of nonvolatile memory devices.


Asunto(s)
Equipos de Almacenamiento de Computador , Grafito/química , Nanopartículas del Metal/química , Nanotecnología/instrumentación , Procesamiento de Señales Asistido por Computador/instrumentación , Plata/química , Impedancia Eléctrica , Diseño de Equipo , Análisis de Falla de Equipo , Nanopartículas del Metal/ultraestructura , Óxidos/química
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