The formation of nanotubes and nanocoils of molybdenum disulphide

This work reports the successful realization of MoS2 nanotubes by a novel intercalation chemistry and hydrothermal treatment. An inorganic-organic precursor of hexadecylamine (HDA) and molybdenum disulphide (MoS2) were used in synthesizing the nanocomposite comprising laminar MoS2 with HDA intercalated in the interlaminar spacing. The formation of MoS2 nanotubes occurred during hydrothermal treatment (HT) by a self-organized rolling mechanism. The nanotubes were observed to have dimensions 2-12 µm in length and inner diameters typically in the range of 25-100 nm. We also report the formation of amorphous nanocoils of MoS2 obtained during similar procedures

Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

This work explores the functionalization of an organic-inorganic MoS2 lamellar compound, prepared by a Chemical Liquid Deposition Method (CLD), that has an interlamellar distance of ~5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of ~85 days, and a zeta potential measured to be ζ = -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS2. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS2

Surfactant-mediated variation of band-edge emission in CdS nanocomposites

The optical-structural characteristics of the direct optical band-gap semiconducting series of surfactant template-mediated laminar (CdS)x(CdCl2)y(CnH2n+4N)z nanocomposites are reported. X-ray diffraction measurements of the nanocomposites exhibited interlaminar distances in the range 2.9-3.6 nm with observations of eighth order {0 0 l} diffraction planes indicative of a high degree of laminarity and crystallographic order. Diffuse reflectance measurements have determined that the profile of their emission spectrum is that of a direct band-gap with absorption edges in the range 2.11-2.40 eV, depending on the CdS mole fraction in the nanocomposite. Photoluminescence (PL) excitation and time-resolved PL spectroscopies give an estimate of the maximum relative absorbance of the nanocomposites at ∼420 nm while the minimum was observed at ∼560 nm. The main emission was observed at ∼700 nm with emission from doubly ionized sulphur vacancies observed at ∼615 nm at room temperature. The CdS-containing nanocomposite is thus a surfactant-mediated modular system with variable band-gap energy emission

The formation of nanotubes and nanocoils of molybdenum disulphide

This work reports the successful realization of MoS2 nanotubes by a novel intercalation chemistry and hydrothermal treatment. An inorganic-organic precursor of hexadecylamine (HDA) and molybdenum disulphide (MoS2) were used in synthesizing the nanocomposite comprising laminar MoS2 with HDA intercalated in the interlaminar spacing. The formation of MoS2 nanotubes occurred during hydrothermal treatment (HT) by a self-organized rolling mechanism. The nanotubes were observed to have dimensions 2-12 µm in length and inner diameters typically in the range of 25-100 nm. We also report the formation of amorphous nanocoils of MoS2 obtained during similar procedures

Surfactant-mediated variation of band-edge emission in CdS nanocomposites

The optical-structural characteristics of the direct optical band-gap semiconducting series of surfactant template-mediated laminar (CdS)x(CdCl2)y(CnH2n+4N)z nanocomposites are reported. X-ray diffraction measurements of the nanocomposites exhibited interlaminar distances in the range 2.9-3.6 nm with observations of eighth order {0 0 l} diffraction planes indicative of a high degree of laminarity and crystallographic order. Diffuse reflectance measurements have determined that the profile of their emission spectrum is that of a direct band-gap with absorption edges in the range 2.11-2.40 eV, depending on the CdS mole fraction in the nanocomposite. Photoluminescence (PL) excitation and time-resolved PL spectroscopies give an estimate of the maximum relative absorbance of the nanocomposites at ∼420 nm while the minimum was observed at ∼560 nm. The main emission was observed at ∼700 nm with emission from doubly ionized sulphur vacancies observed at ∼615 nm at room temperature. The CdS-containing nanocomposite is thus a surfactant-mediated modular system with variable band-gap energy emission

National survey of pre-treatment HIV drug resistance in Cuban patients.

BACKGROUND:The World Health Organization (WHO) recommends a method to estimate nationally representative pretreatment HIV drug resistance (PDR) in order to evaluate the effectiveness of first -line treatments. The objective of the present study was to determine the prevalence of PDR in Cuban adults infected with HIV-1. MATERIALS AND METHODS:A cross-sectional study in Cuban adults infected with HIV-1 over 18 years was conducted. The probability proportional to size method for the selection of municipalities and patients without a prior history of antiretroviral treatment during the period from January 2017 to June 2017 was used. The plasma from 141 patients from 15 municipalities for the determination of viral subtype and HIV drug resistance was collected. Some clinical and epidemiological variables were evaluated. RESULTS:80. 9% of the patients corresponded to the male sex and 76.3% were men who have sex with other men (MSM). The median CD4 count was 371 cells / mm3 and the median viral load was 68000 copies / mL. The predominant genetic variants were subtype B (26.9%), CRF19_cpx (24.1%), CRF 20, 23, 24_BG (23.4%) and CRF18_cpx (12%). Overall, the prevalence of PDR was 29.8% (95%, CI 22.3-38.1). The prevalence was 12.8% (95%, CI 6.07-16.9) for any nucleoside reverse transcriptase inhibitor (NRTI), 23.4% (95%, CI 16.7-31.3) for any non-reverse transcriptase inhibitor (NNRTI) and 1.4% (95%, CI 0.17-5.03) for any protease inhibitor (PI). The most frequent mutations detected were K103N (12.9%), G190A (6.4%) and Y181C (4.8%). CONCLUSIONS:The NNRTI prevalence above 10% in our study indicates that the first-line antiretroviral therapy in Cuba may be less effective and supports the need to look for new treatment options that contribute to therapeutic success and help the country achieve the global goals 90-90-90 set forth by UNAIDS

Caracterización de Moléculas HLA tipo II y evaluación de citocinas en pacientes cubanos con Artritis Reumatoide

La Artritis Reumatoide es una enfermedad de etiología multifactorial, que involucra la presencia de factores genéticos, ambientales, inmunológicos y hormonales. En los últimos años se ha establecido una asociación entre la predisposición a padecer esta enfermedad y la existencia de determinados haplotipos del HLA clase II. El objetivo fundamental de este trabajo es la caracterización del polimorfismo de las moléculas HLA-DQB1 y HLA-DRB de un grupo de pacientes cubanos con Artritis Reumatoide, además analizar una posible correlación entre los niveles de varias citocinas proinflamatorias en un grupo de estos pacientes, con los alelos HLA tipo II genotipados, el sexo y el tiempo de diagnosticada la enfermedad. El estudio se llevo a cabo en 50 pacientes cubanos con el diagnóstico de Artritis Reumatoide y un grupo control, compuesto de 211 donantes sanos. Los haplotipos HLA-DQ y HLA-DRB1 fueron determinados a través de la reacción en cadena de la polimerasa. La cuantificación de las citocinas se realizó empleando inmuno-ensayos comerciales. Los resultados obtenidos en este análisis indican que los alelos con un radio de la razón de probabilidades superior a 2 fueron para el caso de la molécula HLA-DQB1: HLADQB1*03 y *06, y para la molécula HLA-DRB1 los alelos: *01, *04, *09 y *10. Encontramos además que los niveles de la citocina interferón gamma están significativamente aumentados en los pacientes con menos tiempo de diagnosticada la enfermedad. Este trabajo constituye el primer reporte de caracterización de las moléculas HLA tipo II, a través de técnicas moleculares, en pacientes cubanos con Artritis Reumatoide