Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
ACS Nano ; 18(41): 28279-28291, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39367853

RESUMEN

Shape symmetry breaking in the formation of inorganic nanostructures is of significant current interest. It was typically achieved through the growth of colloidal nanoparticles with adsorbed chiral molecules. Photochemical processes induced through asymmetric plasmon excitation by circularly polarized light in surface immobilized nanostructures also led to symmetry breaking. Here, we show that chiral symmetry breaking can be achieved by randomly rotating gold@silver core-shell nanobars in colloidal solution using circularly polarized illumination, where orientational averaging does not eliminate the symmetry breaking of an asymmetric plasmon-induced galvanic replacement reaction. Different morphological effects that are produced by circularly vs linearly polarized light illumination demonstrate the intricate effect of light polarization on the localized plasmonic-induced photochemical response. The essential features of this symmetry breaking, such as illumination wavelength dependence, were reproduced by simulations of circularly polarized light-excited-plasmon-induced hot-electron generation as the source for asymmetric metal deposition. The symmetry breaking becomes smaller in more symmetric geometrical shapes, such as triangular nanoprisms and nanocubes, and down to zero in spherical ones. The degree of symmetry breaking rises when the nanobars are immobilized on a substrate and illuminated from a single direction.

2.
Heliyon ; 9(7): e17971, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37449122

RESUMEN

Using the SILAR method Zinc sulfide coatings were deposited on glass slices. The physical properties and the chemical mechanism throughout the variation in concentration of tri-sodium citrate (TSC) as a chelating agent in the synthesis of thin films were investigated. Results shows that ZnS thin films exhibit an average transmittance of 16% in visible light spectra region and a zinc blende structure. The ZnS films synthesized using TSC as a complexing agent, present a smaller average particle size, an average transmittance of 85%, and an adsorption edge at 300-340 nm. Based on our experimental data and analysis, we conclude that the contribution of the oxychloride species, a subproduct in the chemical deposition, is suggested to be related as an impurity level former in the synthesis of ZnS thin films. TSC as a complexing agent in the SILAR technique is a non-toxic option to reduce the generation of the oxychloride species and synthesize a wide band gap semiconductor. Moreover, the use of complexing agents could be extended to other types of semiconductors deposited by SILAR.

3.
Nanoscale Adv ; 5(10): 2776-2784, 2023 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-37205288

RESUMEN

As we strive to perform chemical transformations in a more sustainable fashion, enabling solid-state reactions through mechanochemistry has emerged as a highly successful approach. Due to the wide-ranging applications of gold nanoparticles (AuNPs), mechanochemical strategies have already been employed for their synthesis. However, the underlying processes surrounding gold salt reduction, nucleation and growth of AuNPs in the solid state are yet to be understood. Here, we present a mechanically activated aging synthesis of AuNPs, through a solid-state Turkevich reaction. Solid reactants are only briefly exposed to input of mechanical energy before being aged statically over a period of six weeks at different temperatures. This system offers an excellent opportunity for an in situ analysis of both reduction and nanoparticle formation processes. During the aging period, the reaction was monitored using a combination of X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, powder X-ray diffraction and transmission electron microscopy, to gain meaningful insights into the mechanisms of solid-state formation of gold nanoparticles. The acquired data allowed for the establishment of the first kinetic model for solid-state nanoparticle formation.

4.
Cir Cir ; 91(2): 253-261, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37084294

RESUMEN

OBJECTIVE: Provide a description of clinical characteristics, associated factors and outcome of tracheostomies performed in COVID-19 patients. METHOD: Observational prospective study of 14 patients who underwent tracheostomy. 10 of them were diagnosed with COVID 19, confirmed with RT-PCR test of nasopharyngeal exudate and compatible tomographic findings. RESULTS: Of the 10 patients, five were discharged and five died. The average age of patients who died was 66.6 years; of those who were discharged, it was 60.4 years. Ventilatory parameters cut was taken as FiO2 ≤ 40% and PEEP ≤ 8; of the patients discharged, four met both criteria. On the other hand, of the patients who died, neither met both. Of the latter, an average of APACHE II of 16.4 and SOFA 7.4 were documented, while in discharged patients an average of 12.6 and 4.6 were observed, respectively. CONCLUSIONS: Tracheostomy performed in patients with specific criteria, such as low ventilatory parameters, age, or low score in severity scales, may have a better prognosis.


OBJETIVO: Realizar una descripción de las características clínicas, los factores asociados y el desenlace de las traqueostomías realizadas en pacientes con COVID-19. MÉTODO: Estudio retrospectivo observacional de 14 pacientes a quienes se realizó traqueostomía. Diez de ellos se encontraban diagnosticados con COVID-19, confirmada con prueba RT-PCR de exudado nasofaríngeo y hallazgos tomográficos compatibles. RESULTADOS: De los 10 pacientes, cinco fueron dados de alta y cinco fallecieron. La edad promedio de los pacientes que fallecieron fue de 66.6 años, y la de los que fueron dados de alta fue de 60.4 años. De los parámetros ventilatorios, se tomó como corte una FiO2 ≤ 40% y una PEEP ≤ 8; entre los pacientes dados de alta, cuatro cumplían con ambos criterios. En cambio, de los pacientes que fallecieron, ninguno los cumplió. En estos últimos se documentó un promedio de APACHE II de 16.4 y un SOFA de 7.4, mientras que en los pacientes dados de alta se observó un promedio de 12.6 y 4.6, respectivamente. CONCLUSIONES: La traqueostomía realizada en pacientes con criterios específicos, como parámetros ventilatorios bajos, edad o puntuación baja en las escalas de gravedad, pueden llegar a tener mejor pronóstico.


Asunto(s)
COVID-19 , Anciano , Humanos , Hospitales , México/epidemiología , Pronóstico , Estudios Prospectivos , Traqueostomía
5.
Nano Lett ; 23(12): 5842-5850, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-36995289

RESUMEN

Plasmonic polymeric nanoassemblies offer valuable opportunities in photoconversion applications. Localized surface plasmon mechanisms behind such nanoassemblies govern their functionalities under light illumination. However, an in-depth investigation at the single nanoparticle (NP) level is still challenging, especially when the buried interface is involved, due to the availability of suitable techniques. Here, we synthesized an anisotropic heterodimer composed of a self-assembled polymer vesicle (THPG) capped with a single gold NP, enabling an 8-fold enhancement in hydrogen generation compared to the nonplasmonic THPG vesicle. We explored the anisotropic heterodimer at the single particle level by employing advanced transmission electron microscopes, including one equipped with a femtosecond pulsed laser, which allows us to visualize the polarization- and frequency-dependent distribution of the enhanced electric near fields at the vicinity of Au cap and Au-polymer interface. These elaborated fundamental findings may guide designing new hybrid nanostructures tailored for plasmon-related applications.

6.
Faraday Discuss ; 241(0): 278-288, 2023 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-36218357

RESUMEN

We use a gold nanoparticle synthesis as a model system to study the morphological and compositional changes in gold(III) precursor particles, while reduction is taking place during aging after mechanical activation. Scanning transmission electron microscopy coupled with a high-angle annular dark field detector revealed the nanoscale changes in particle morphology, while electron energy loss spectroscopy mapped the changes in the chemical landscape during the reduction process. Tracking a specific region of interest on the sample grid allowed for comparisons to be made of the same particles across a two day monitoring period. High-angle annular dark field images permitted the visualization of particle size reduction of the gold salt while electron energy loss spectroscopy captured the surprising mobility of the lighter chlorine and sodium ions in a solid matrix during the reduction process. This system offers unique insight into precursor particle reactivity in the solid phase, which is relevant for many mechanochemical and aging-based reactions.

7.
Adv Mater ; 35(3): e2207950, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36300600

RESUMEN

Polymer-inorganic hybrid Janus nanoparticles (PI-JNPs) have attracted extensive attention due to their special structures and functions. However, achieving the synergistic enhancement of photochemical activity between polymer and inorganic moieties in PI-JNPs remains challenging. Herein, the construction of a novel Janus Au-porphyrin polymersome (J-AuPPS) heterostructure by a facile one-step photocatalytic synthesis is reported. The near-field enhancement (NFE) effect between porphyrin polymersome (PPS) and Au nanoparticles in J-AuPPS is achieved to enhance its near-infrared (NIR) light absorption and electric/thermal field intensity at their interface, which improves the energy transfer and energetic charge-carrier generation. Therefore, J-AuPPS shows a higher NIR-activated photothermal conversion efficiency (48.4%) and generates more singlet oxygen compared with non-Janus core-particle Au-PPS nanostructure (28.4%). As a result, J-AuPPS exhibits excellent dual-mode (photothermal/photodynamic) antibacterial and anti-biofilm performance, thereby significantly enhancing the in vivo therapeutic effect in an implant-associated-infection rat model. This work is believed to motivate the rational design of advanced hybrid JNPs with desirable NFE effect and further extend their biological applications.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Nanoestructuras , Ratas , Animales , Oro/química , Nanopartículas del Metal/uso terapéutico , Nanopartículas del Metal/química , Fototerapia , Polímeros/química
8.
Beilstein J Org Chem ; 18: 1203-1209, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36158176

RESUMEN

Herein, we present the bottom-up, mechanochemical synthesis of phosphorus-bridged heptazine-based carbon nitrides (g-h-PCN). The structure of these materials was determined through a combination of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), 31P magic angle spinning nuclear magnetic resonance (MAS NMR), density functional theory (DFT) and electron energy loss spectroscopy (EELS). Compared to traditional furnace-based techniques, the presented method utilizes milder conditions, as well as shorter reaction times. Both samples of g-h-PCN directly after milling and aging and after an hour of annealing at 300 °C (g-h-PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis.

10.
Saudi J Kidney Dis Transpl ; 32(1): 245-248, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34145140

RESUMEN

Fungal peritonitis (FP) is a rare complication of peritoneal dialysis (PD). Candida tropicalis infections are rarely reported in literature. The authors present the first case of FP with peritoneal abscess due to C. tropicalis in a 22-year-old woman admitted to our hospital with septic shock. Abdominal tomography demonstrated an abscess in peritoneal space and intraluminal bubble appearance in femoral venous and arterial circulation. PD fluid specimens and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis revealed fungus growth of C. tropicalis. Fluconazole therapy was administered accompanied by catheter removal and mechanical ventilation with vasopressor support. The patient recovered after 23 days of hospitalization and was discharged. FP represents high mobility and mortality unless infection source control and appropriate antimicrobial therapy are implemented accompanied by PD catheter removal. The use of MALDI-TOF MS for PD-related peritonitis pathogen identification can promote early identification and appropriate antibiotic therapy, especially in C. tropicalis infection.


Asunto(s)
Candida tropicalis , Candidiasis/diagnóstico , Diálisis Peritoneal , Peritonitis/diagnóstico , Femenino , Humanos , Peritonitis/microbiología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Adulto Joven
11.
Spec Care Dentist ; 41(5): 644-649, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34018635

RESUMEN

AIM: To develop a device to aid in insertion and removal of dentures in patients with limited range of motion. CASE REPORT: A 62-year-old male with congenital musculoskeletal system anomaly, severe scoliosis, missing teeth, and poor dentition presented for comprehensive dental care. Patient had significant range of motion limitations resulting in an inability to reach his mouth. A device allowing for independent insertion, removal, and cleaning of dentures was made for patient. Dentures were fabricated and scanned using an intraoral scanner, traditional surgical guide for implant placement was adapted to accommodate neodynium magnets and wooden dowel, and guide was 3D printed. Stainless steel spheres were processed into denture to correspond to magnets in guide. Patient demonstrated ability to independently insert and remove both his maxillary complete denture and mandibular partial denture using device. CONCLUSION: A successful device for insertion and removal of complete and partial dentures can be fabricated by adapting a surgical guide to incorporate magnets by processing stainless steel spheres into the dentures. This device could be helpful for any individuals demonstrating musculoskeletal system anomalies or range of motion deficits.


Asunto(s)
Dentadura Completa , Mandíbula , Humanos , Masculino , Maxilar , Persona de Mediana Edad , Rango del Movimiento Articular
12.
Nat Commun ; 12(1): 1231, 2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33623017

RESUMEN

Conversion of clean solar energy to chemical fuels is one of the promising and up-and-coming applications of metal-organic frameworks. However, fast recombination of photogenerated charge carriers in these frameworks remains the most significant limitation for their photocatalytic application. Although the construction of homojunctions is a promising solution, it remains very challenging to synthesize them. Herein, we report a well-defined hierarchical homojunction based on metal-organic frameworks via a facile one-pot synthesis route directed by hollow transition metal nanoparticles. The homojunction is enabled by two concentric stacked nanoplates with slightly different crystal phases. The enhanced charge separation in the homojunction was visualized by in-situ surface photovoltage microscopy. Moreover, the as-prepared nanostacks displayed a visible-light-driven carbon dioxide reduction with very high carbon monooxide selectivity, and excellent stability. Our work provides a powerful platform to synthesize capable metal-organic framework complexes and sheds light on the hierarchical structure-function relationships of metal-organic frameworks.

14.
J. bras. nefrol ; 42(4): 484-488, Oct.-Dec. 2020. tab, graf
Artículo en Inglés, Portugués | LILACS | ID: biblio-1154625

RESUMEN

ABSTRACT Introduction: Idiopathic nodular glomerulosclerosis (ING) is a condition that has a vasculopathic glomerular histological pattern. Case presentation: The authors present the case of a 44-year-old Hispanic smoker female with hypertension and peripheral arterial disease who presented nephrotic syndrome for 2 weeks. The patient was diagnosed with ING by percutaneous renal biopsy results, which showed global nodular mesangial matrix expansion, with linear staining accentuation of glomerular and tubular basement membrane for Immunoglobulin G (IgG) and albumin on immunofluorescence. Conclusions: ING is a rare disease with a poor renal prognosis and wide diagnostic approach; we highlight the importance of analyzing every piece of detail together to reach a definitive diagnosis.


RESUMO Introdução: A glomerulosclerose nodular idiopática (GNI) tem um padrão histológico glomerular vasculopático. Apresentação do caso: Os autores apresentam o caso de uma mulher latino-americana, de 44 anos, fumante, com hipertensão e doença arterial periférica; com síndrome nefrótica por 2 semanas. Ela foi diagnosticada com GNI por biópsia renal percutânea, que mostrou expansão generalizada da matriz mesangial nodular, com acentuação de coloração linear na membrana basal glomerular e tubular para imunoglobulina G (IgG) e albumina à imunofluorescência. Conclusões: A GNI é uma doença rara, com mau prognóstico renal, e com necessidade de uma ampla abordagem diagnóstica. Demonstramos aqui a importância de se analisar todos os detalhes em conjunto para realizar um diagnóstico definitivo.


Asunto(s)
Humanos , Femenino , Adulto , Nefropatías Diabéticas/diagnóstico , Hipertensión , Síndrome Nefrótico , Diagnóstico Diferencial , Riñón
15.
Food Sci Nutr ; 8(8): 4555-4564, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32884735

RESUMEN

Oregano essential oils from Lippia berlandieri Schauer (Lb) and Poliomintha longiflora Gray (Pl) were tested against the antioxidant butylated hydroxytoluene (Bht) to evaluate effects on the shelf life of ground beef (GB) over 7 days of storage at 4°C. The treatments were GB1 = GB control, GB2 = GB +100 mg/kg of Bht, GB3 = GB +100 mg/kg of Lb, and GB4 = GB +100 mg/kg of Pl. Lightness, redness, hardness, and springiness showed differences (p < .05) between treatments and days interaction, which serve as indicators of ground beef preserved quality and consumer acceptance. Mesophilic, psychrophilic, and lactic acid bacteria numbers and antioxidant activity showed differences (p < .05) for treatments and days. Sensory attributes showed no differences between treatments. The oregano oils may provide extended shelf life for packaged meat products treated with these natural additives and hence may be used for ground beef preservation.

16.
J Bras Nefrol ; 42(4): 484-488, 2020.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-32776085

RESUMEN

INTRODUCTION: Idiopathic nodular glomerulosclerosis (ING) is a condition that has a vasculopathic glomerular histological pattern. CASE PRESENTATION: The authors present the case of a 44-year-old Hispanic smoker female with hypertension and peripheral arterial disease who presented nephrotic syndrome for 2 weeks. The patient was diagnosed with ING by percutaneous renal biopsy results, which showed global nodular mesangial matrix expansion, with linear staining accentuation of glomerular and tubular basement membrane for Immunoglobulin G (IgG) and albumin on immunofluorescence. CONCLUSIONS: ING is a rare disease with a poor renal prognosis and wide diagnostic approach; we highlight the importance of analyzing every piece of detail together to reach a definitive diagnosis.


Asunto(s)
Nefropatías Diabéticas , Hipertensión , Síndrome Nefrótico , Adulto , Nefropatías Diabéticas/diagnóstico , Diagnóstico Diferencial , Femenino , Humanos , Riñón
17.
Nanoscale ; 11(29): 13790-13799, 2019 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-31292584

RESUMEN

The structural details of nanoparticles at the sub-particle level are critical for our understanding of their functionalities and the basic mechanisms involved in their formation. In particular, the geometries of such features determine the particle's overall optical response. Hollow metallic nanoparticles (hollow-MNPs) that have cubic geometries, with varying morphologies on their walls and voids in their body, offer a platform to study the effects of such structural features on the properties of single nanoparticles and their ensemble. Here, we report the control over sub-particle pinholes and voids by modifying the dynamics of the galvanic reaction, and we connect these structures to the optical response of the hollow nanocubes. We observe that symmetry breakage in individual particles, caused by pinholes and voids, has a drastic effect on the plasmon-resonance peak positions in their UV-Vis-NIR spectra. Via electron microscopy imaging, statistical analyses, and electromagnetic simulations, we observe that enlargement in a pinhole's diameter and an increase in their number produce a redshift in the resonance absorption peak of the ensemble. Our results outline nanoparticle design avenues via sub-particle morphologies for several applications, including those operating in the biological window and those carrying chemical payloads in organisms.

18.
Dent Clin North Am ; 62(1): 143-154, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29126491

RESUMEN

The clinical manifestations of oral cancer and the effects of treatment can have a negative impact on a patient's quality of life. Physiologic functions, cosmetic appearance, and psychological well-being can become compromised during the diagnosis, treatment, and survivorship of patients with oral cancer. This article addresses the relationship of oral cancer and quality of life, as well as the different aspects affected by this condition.


Asunto(s)
Neoplasias de la Boca/complicaciones , Neoplasias de la Boca/psicología , Neoplasias de la Boca/terapia , Salud Bucal , Calidad de Vida , Humanos , Sobrevivientes/psicología
20.
Ther Apher Dial ; 21(5): 459-464, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28805348

RESUMEN

Intradialytic hypotension is common complication in stage 5 chronic kidney disease patients on hemodialysis. Incidence ranges from 15 to 30%. These patients have levocarnitine deficiency. A randomized, placebo-controlled quadruple-blinded trial was designed to demonstrate the levocarnitine efficiency on intradialytic hypotension prevention. Patients were randomized into four groups, to receive levocarnitine or placebo. During the intervention period, levocarnitine and placebo was administered 0 and 30 min before each hemodialysis session, respectively. During the trial, 33 patients received 1188 hemodialysis sessions. We identified 239 (21.3%) intradialytic hypotension episodes. The intradialytic hypotension episodes were less frequent in the levocarnitine group (9.3%, 60 IH events) (P < 0.001). Hemodialysis is frequently perplexed by intradialytic hypotension episodes. Levocarnitine supplementation before each hemodialysis session efficiently diminishes the intradialytic hypotension episodes. This is a new application method that must be considered and explored.


Asunto(s)
Carnitina/administración & dosificación , Hipotensión/prevención & control , Fallo Renal Crónico/terapia , Diálisis Renal/métodos , Adulto , Carnitina/deficiencia , Método Doble Ciego , Femenino , Humanos , Hipotensión/epidemiología , Hipotensión/etiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Diálisis Renal/efectos adversos , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA