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1.
Water Sci Technol ; 87(8): 1803-1818, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37119156

RESUMEN

The aim of this study was to evaluate the efficiency of catalytic ozonation to increase the degradation of aqueous N-methyldiethanolamine (MDEA) solutions, using two lamellar double hydroxides, namely MgxFe-LDH with x = Mg/Fe = 2, 3, were synthesized by the simple and rapid co-precipitation method. Then, the obtained materials were calcined at 400 °C for 6 h. The calcined products were respectively designated as HTcMg2Fe and HTcMg3Fe, and characterized by powder X-ray diffraction (XRD), N2 physisorption (BET), Fourier transform infrared spectra (FT-IR), and scanning electron microscopy (SEM). The powders produced were used in the ozonation reaction to remove MDEA from aqueous solutions. Experimental results showed that the highest MDEA removal efficiency is in the catalytic ozonation process. Under the optimal conditions for heterogeneous catalytic ozonation of MDEA: initial concentration of 4 Wt% MDEA, 30 °C, catalyst mass of 30 mg/100 ml solution, and contact time of 60 min. The results showed the highest percentage of COD removal, which was up to 80.76% for HTcMg2Fe higher than that of HTcMg3Fe 80.36%.


Asunto(s)
Óxidos , Ozono , Espectroscopía Infrarroja por Transformada de Fourier , Catálisis
2.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33806355

RESUMEN

Basic research on types 1 and 2 diabetes mellitus require early stage studies using beta cells or cell lines, ideally of human origin and with preserved insulin secretion in response to glucose. The 1.1E7 cells are a hybrid cell line resulting from the electrofusion of dispersed human islets and PANC-1 cells, capable of secreting insulin in response to glucose, but their survival and function under toxic conditions remains untested. This characterization is the purpose of the present study. We treated these cells with a cytokine mix, high glucose, palmitate, and the latter two combined. Under these conditions, we measured cell viability and apoptosis (MTT, Caspase Glo and TUNEL assays, as well as caspase-8 and -9 levels by Western blotting), endoplasmic reticulum stress markers (EIF2AK3, HSPA4, EIF2a, and HSPA5) by real-time PCR, and insulin secretion with a glucose challenge. All of these stimuli (i) induce apoptosis and ER stress markers expression, (ii) reduce mRNA amounts of 2-5 components of genes involved in the insulin secretory pathway, and (iii) abrogate the insulin release capability of 1.1E7 cells in response to glucose. The most pronounced effects were observed with cytokines and with palmitate and high glucose combined. This characterization may well serve as the starting point for those choosing this cell line for future basic research on certain aspects of diabetes.


Asunto(s)
Citocinas/toxicidad , Glucosa/toxicidad , Secreción de Insulina/efectos de los fármacos , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Palmitatos/toxicidad , Apoptosis/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Citocinas/administración & dosificación , Citocinas/metabolismo , Diabetes Mellitus/etiología , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patología , Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico/efectos de los fármacos , Estrés del Retículo Endoplásmico/genética , Expresión Génica/efectos de los fármacos , Glucosa/administración & dosificación , Glucosa/metabolismo , Humanos , Secreción de Insulina/genética , Células Secretoras de Insulina/citología , Palmitatos/administración & dosificación , Palmitatos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo
3.
J Vasc Bras ; 20: e20200095, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34630537

RESUMEN

Mycotic pseudoaneurysms of the superficial femoral artery (SFA) are rare and are usually secondary to colonization of an atherosclerotic plaque during an episode of bacteremia. We describe the case of a 68 year-old diabetic male who presented to the Emergency Department with pyrexia and a painful expanding mass in the left thigh. He had a history of diarrhea and had been treated 16 days earlier for an SFA pseudoaneurysm that had been excluded with a covered stent with no adjunctive antibiotic therapy. Angio CT showed an abscess surrounding femoral vessels and stent thrombosis. Under general anesthesia, we performed extensive debridement, removal of the endovascular material, SFA ligation, and empirical antibiotic therapy. Blood and tissue cultures were positive for Escherichia coli. At the 3-months follow up visit, the patient reported he had no claudication. In selected patients, mycotic pseudoaneurysms can be treated by SFA ligation.


Pseudoaneurismas micóticos da artéria femoral superficial (AFS) são raros, e geralmente são secundários à colonização de uma placa aterosclerótica durante bacteremia. Relatamos o caso de um paciente masculino diabético de 68 anos que chegou ao Serviço de Emergência com pirexia e massa expansiva dolorosa na coxa esquerda. Apresentava histórico de diarreia e havia sido tratado 16 dias antes para pseudoaneurisma da AFS, que foi excluído com stent coberto e sem antibioticoterapia adjuvante. A angiotomografia computadorizada demonstrou um abscesso ao redor dos vasos femorais e trombose do stent. Sob anestesia geral, realizamos desbridamento extenso, remoção do material endovascular, ligadura de AFS e antibioticoterapia empírica. Culturas de sangue e tecidos foram positivas para Escherichia coli. Na consulta de seguimento aos 3 meses, o paciente negou claudicação. Em pacientes selecionados, pseudoaneurismas micóticos podem ser tratados com ligadura de AFS.

4.
Radiographics ; 39(7): 2023-2037, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31697616

RESUMEN

Extrapulmonary tuberculosis (TB) represents approximately 15% of all TB infections. It is difficult to diagnose on the basis of imaging characteristics and clinical symptoms, and biopsy is required in many cases. Radiologists must be aware of the imaging findings of extrapulmonary TB to identify the condition in high-risk patients, even in the absence of active pulmonary infection. In extrapulmonary TB, the lymphatic system is most frequently affected. The presence of necrotic lymph nodes and other organ-specific imaging features increases the diagnostic probability of extrapulmonary TB. Disseminated infection and central nervous system involvement are the most frequent manifestations in immunosuppressed patients. Renal disease can occur in immunocompetent patients with very long latency periods between the primary pulmonary infection and genitourinary involvement. In several cases, gastrointestinal, solid-organ, and peritoneal TB show nonspecific imaging findings. Tuberculous spondylitis is the most frequent musculoskeletal manifestation. It is usually diagnosed late and affects multiple vertebral segments with extensive paraspinal abscess. Articular disease is the second most frequent musculoskeletal manifestation, and synovitis is its predominant imaging finding.©RSNA, 2019.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Tuberculosis/diagnóstico por imagen , Absceso/diagnóstico por imagen , Absceso/fisiopatología , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Enfermedades Musculares/diagnóstico por imagen , Enfermedades Musculares/fisiopatología , Riesgo , Tuberculoma/diagnóstico por imagen , Tuberculosis/fisiopatología , Tuberculosis del Sistema Nervioso Central/diagnóstico por imagen , Tuberculosis del Sistema Nervioso Central/fisiopatología , Tuberculosis Ganglionar/diagnóstico por imagen , Tuberculosis Ganglionar/fisiopatología , Tuberculosis Meníngea/diagnóstico por imagen , Tuberculosis Meníngea/fisiopatología , Tuberculosis Osteoarticular/diagnóstico por imagen , Tuberculosis Osteoarticular/fisiopatología , Tuberculosis Urogenital/diagnóstico por imagen , Tuberculosis Urogenital/fisiopatología
5.
Opt Express ; 25(20): 24670-24677, 2017 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-29041412

RESUMEN

Extraordinary transmission has been recently measured in a parallel plate waveguide (PPWG) through a metal strip with a patterned 1-D periodic array of circular holes, the metal strip being embedded inside the PPWG. Wood's anomaly and the extraordinary transmission peak (EOT) were detected for transverse electric (TE) mode excitation at frequencies higher than those found for TEM mode excitation. In this paper we provide an explanation for this frequency shift by decomposing the problem of a TE mode impinging on the 1-D array of holes into two problems of plane waves impinging obliquely on 2-D periodic arrays of holes. By then solving the integral equation for the electric field on the surface of the holes, the origin of the frequency shift is proved both mathematically and physically in terms of the symmetries present in the system.

6.
BMC Musculoskelet Disord ; 18(1): 400, 2017 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-28923050

RESUMEN

BACKGROUND: Shoulder pain of musculoskeletal origin is the main cause of upper limb pain of non-traumatic origin. Despite being one of the most common reasons for consultation, there is no established protocol for treatment due to the complexity of its etiology. However, it has been shown that the presence of myofascial trigger points on the shoulder muscles is a common condition associated with patients suffering from shoulder pain. This protocol has been created which describes the design of a randomized controlled trial to evaluate the effectiveness of the inclusion of dry needling (DN) within a protocol of manual physiotherapy and therapeutic exercise in the treatment of chronic shoulder pain of unspecific origin. METHODS: Thirty-six participants aged 18-65 years will be recruited having mechanical chronic shoulder pain on unspecific origin and meeting the inclusion criteria. These will be randomized to one of two interventions, (i) DN, manual physiotherapy and therapeutic exercise or (ii) sham DN, manual physiotherapy and therapeutic exercise. The protocol will cover 6 weeks of treatment, with a 6-month follow-up. Our main outcome measure will be the Visual Analogue Scale for pain. DISCUSSION: This is the first study to combine the use of DN, manual physiotherapy and an exercise program with a 6-month follow-up, thus becoming a new contribution to the treatment of chronic shoulder pain, while new lines of research may be established to help determine the effects of DN on chronic shoulder pain and the frequency and proper dosage. TRIAL REGISTRATIONS: International Standard Randomized Controlled Trial Number Register: ISRCTN30604244 ( http://www.controlled-trials.com ) 29 June 2016.


Asunto(s)
Terapia por Acupuntura/métodos , Dolor Crónico/terapia , Terapia por Ejercicio/métodos , Modalidades de Fisioterapia , Dolor de Hombro/terapia , Adolescente , Adulto , Anciano , Dolor Crónico/diagnóstico , Dolor Crónico/epidemiología , Terapia Combinada/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor/métodos , Dolor de Hombro/diagnóstico , Dolor de Hombro/epidemiología , Método Simple Ciego , Adulto Joven
7.
Opt Express ; 24(10): 10265-74, 2016 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-27409851

RESUMEN

Solid metal films are well known to be opaque to electromagnetic waves over a wide frequency range, from low frequency to optics. High values of the conductivity at relatively low frequencies or negative values of the permittivity at the optical regime provide the macroscopic explanation for such opacity. In the microwave range, even extremely thin metal layers (much smaller than the skin depth at the operation frequency) reflect most of the impinging electromagnetic energy, thus precluding significant transmission. However, a drastic resonant narrow-band enhancement of the transparency has recently been reported. The quasi-transparent window is opened by placing the metal film between two symmetrically arranged and closely spaced copper strip gratings. This letter proposes an analytical circuit model that yields a simple explanation to this unexpected phenomenon. The proposed approach avoids the use of lengthy numerical calculations and suggests how the transmissivity can be controlled and enhanced by manipulating the values of the electrical parameters of the associated circuit model.

8.
Rev Med Chil ; 144(4): 451-5, 2016 Apr.
Artículo en Español | MEDLINE | ID: mdl-27401376

RESUMEN

BACKGROUND: Postoperative leaks are the most undesirable complication of bariatric surgery and upper gastrointestinal (GI) series are routinely ordered to rule them out. Despite the published literature recommending against its routine use, it is still being customarily used in Chile. AIM: To examine the usefulness of routine upper GI series using water-soluble iodinated contrast media for the detection of early postoperative leaks in patients undergoing bariatric surgery. MATERIAL AND METHODS: A cohort of 328 patients subjected to bariatric surgery was followed from October 2012 to October 2013. Most of them underwent sleeve gastrectomy. RESULTS: Upper GI series on the first postoperative day were ordered to 308 (94%) patients. Postoperative leaks were observed in two patients, with an incidence of 0.6%. The sensitivity for upper GI series detection of leak was 0% and the negative predictive value was 99%. CONCLUSIONS: Routine upper GI series after bariatric surgery is not useful for the diagnosis of postoperative leak, given the low incidence of this complication and the low sensitivity of the technique.


Asunto(s)
Fuga Anastomótica/diagnóstico por imagen , Cirugía Bariátrica/efectos adversos , Tracto Gastrointestinal Superior/diagnóstico por imagen , Adulto , Fuga Anastomótica/etiología , Medios de Contraste , Femenino , Gastrectomía/efectos adversos , Humanos , Laparoscopía/efectos adversos , Masculino , Persona de Mediana Edad , Obesidad Mórbida/cirugía , Periodo Posoperatorio , Estudios Prospectivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos X/métodos
9.
Tumour Biol ; 36(12): 9285-93, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26104766

RESUMEN

Axillary lymph nodes status is the most important prognosis factor in early breast cancer. This status is known by a selective sentinel lymph node biopsy (SLNB) and/or lymphadenectomy. Immunohistochemical studies of breast cancer tumour tissue have reported a relation between the increased expression of vascular endothelial growth factor-C (VEGF-C) and the risk of lymph node metastasis. We researched whether serum levels of VEGF-C could be a predictor factor of sentinel lymph node status in these patients. A prospective analysis was performed on serum from 174 patients with early breast cancer who underwent SLNB. The level of VEGF-C was determined by enzyme-linked immunosorbent assay. Clinical-pathologic variables were collected. Univariate analysis and multivariate logistic regression were conducted, taking SLNB positivity as the segmentation variable. The predictive value of VEGF-C was assessed using ROC curves. Of the sample group of 167 patients, 64 (38.3 %) had affected lymph node. Eighteen patients (28.1 %) presented micrometastasis; there were isolated tumour cells in 11 cases (17.2 %) and macrometastasis in 35 (54.6 %). The median value of VEGF-C was 6561.5 pg/ml. These values did not correlate with any clinical variables, and there was no association between the level of VEGF-C and SLNB status (p = 0.626). In the multivariate analysis, tumour size (p = 0.009) and the presence of vascular invasion (p < 0.001) were independently associated with sentinel lymph node affected. Serum levels of VEGF-C do not appear to predict sentinel lymph node status in patients with early breast cancer who undergo SLNB.


Asunto(s)
Neoplasias de la Mama/sangre , Ganglios Linfáticos/patología , Linfangiogénesis/genética , Factor C de Crecimiento Endotelial Vascular/sangre , Adulto , Anciano , Axila/patología , Neoplasias de la Mama/patología , Femenino , Humanos , Metástasis Linfática , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Biopsia del Ganglio Linfático Centinela
10.
Materials (Basel) ; 17(18)2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39336289

RESUMEN

The fatigue performance of laser powder bed fusion-fabricated Ti-6Al-4V alloy was investigated using four-point bending testing. Specifically, the effects of keyhole and lack-of-fusion porosities along with various surface roughness parameters, were evaluated in the context of pore circularity and size using 2D optical metallography. Surface roughness of Sa = 15 to 7 microns was examined by SEM, and the corresponding fatigue performance was found to vary by 102 cycles to failure. The S-N curves for the various defects were also correlated with process window examination in laser beam power-velocity (P-V) space. Basquin's stress-life relation was well fitted to the experimental S-N curves for various process parameters except keyhole porosity, indicating reduced importance for LPBF-fabricated Ti-6Al-4V alloy components.

11.
Aliment Pharmacol Ther ; 60(10): 1325-1338, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39287363

RESUMEN

BACKGROUND: Ustekinumab is approved for ulcerative colitis (UC). AIMS: To assess the durability of ustekinumab in patients with UC and its short-term effectiveness, durability and tolerability in clinical practice. METHODS: Retrospective, multicentre study of patients who had received their first ustekinumab dose at least 16 weeks before inclusion. Patients were followed until treatment discontinuation or last visit. Only patients with active disease at the start of ustekinumab treatment were considered in the effectiveness analysis. Patients who stopped ustekinumab before their last visit were considered not to be in subsequent remission. RESULTS: We included 620 patients; 155 (25%) discontinued ustekinumab during follow-up (median 12 months). Rate of discontinuation was 20% per patient-year of follow-up. Anaemia at baseline (hazard ratio, HR 1.5; 95% confidence interval [CI] 1.1-2.1), steroids at baseline (HR 1.5; 95% CI 1.06-2.08) and more severe clinical activity at baseline (HR 1.5; 95% CI 1.09-2.06) were associated with higher risk of discontinuation. At the end of induction, 226 (40%) patients were in steroid-free clinical remission. Moderate-severe vs mild disease activity at baseline (odds ratio [OR] 0.3; 95% CI 0.2-0.5), male sex (OR 0.5; 95% CI 0.4-0.8), and increased number of previous biologics (OR 0.6; 95% CI 0.6-0.8) were associated with lower likelihood of steroid-free clinical remission at week 16. One hundred and seventy-six patients (28%) had at least one adverse event. We observed no negative impact of ustekinumab on extraintestinal manifestations and/or immune-mediated diseases. CONCLUSIONS: Ustekinumab durability in UC was relatively high, and treatment was effective in highly refractory patients. The safety profile was consistent with previous studies.


Asunto(s)
Colitis Ulcerosa , Ustekinumab , Humanos , Ustekinumab/uso terapéutico , Colitis Ulcerosa/tratamiento farmacológico , Masculino , Femenino , Estudios Retrospectivos , Adulto , Persona de Mediana Edad , Resultado del Tratamiento , Inducción de Remisión , Índice de Severidad de la Enfermedad
12.
Rev Neurosci ; 24(5): 507-25, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24077617

RESUMEN

It has been almost 40 years since Barker, Jalinous, and Freeston designed and used the first device of transcranial magnetic stimulation (TMS). From then until now, this technique has evolved vertiginously, appearing a lot of new protocols and device modifications, which associated with new technologies complement and enhance the versatility of this technique. TMS has demonstrated to be a safe technology and become a key tool in the study of the complex brain processes. Despite this, it is as a therapeutic tool where this technique has caused a revolution. In this regard, this type of non-invasive brain stimulation has been proven useful in a variety of neurodegenerative and psychiatric disorders due to its biochemical, molecular, and cellular effects, with depression being the paradigm of the therapeutic effectiveness of this technique. This review focuses on a detailed vision of how this type of radiation modifies different biochemical and cellular processes that induce the mechanisms and pathways underlying the therapeutic effects of TMS.


Asunto(s)
Encéfalo/fisiología , Trastornos Mentales/terapia , Enfermedades Neurodegenerativas/terapia , Estimulación Magnética Transcraneal/métodos , Encéfalo/ultraestructura , Humanos , Mitocondrias/fisiología , Neuronas/ultraestructura , Neurotransmisores/metabolismo
13.
Phys Chem Chem Phys ; 15(37): 15645-59, 2013 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-23942769

RESUMEN

PLLs were synthesized by the ring-opening polycondensation (ROP) method using α-L-leucine N-carboxyanhydride (NCA) and initialized by triethylamine (Et3N), water or rehydrated hydrotalcite (HTrus). The role of temperature, different initiators and water in ROP was further investigated. In general, the initiators used in the polymerization reaction lead to PLL alpha-helical chains containing 5-40 monomers with NCA endgroups via a monomer-activated mechanism. However, the water has a twofold effect on ROP, as both a nucleophile and a base, which involves competition between two different types of initiating mechanisms (nucleophilic attack or deprotonation of the NCA monomer) in the polymerization reaction. This competition provides as a main product NCA endgroups with an alpha-helical structure and leads to the formation of the PLL cyclic-chains and beta-sheet structures which reduce the polymer Mw and the PD of the polypeptide. Furthermore, the water can hydrolyze the NCA endgroups resulting in PLL alpha-helical chains that contain living groups as the main product. On the other hand, the HTrus presents a double role: as both an initiator and a support. The polymers synthesized in the presence of HTrus presented a HT-carboxylate endgroup. The PLLs immobilized in HTrus through an anion-exchange method performed for just 30 minutes presented the PLL immobilized in the interlayer space of the HTrus. The PLL chains of the immobilized counterpart are stabilized by H-bonding with the M-OH of the HT structure. All the polypeptides and biohybrid materials synthesized have been characterized using different techniques (EA, ICP, XRD, Raman, MALDI-TOF, ESI-TOF, FT-IR at increasing temperatures, TG/DT analyses and TEM).


Asunto(s)
Hidróxido de Aluminio/química , Hidróxido de Magnesio/química , Péptidos/síntesis química , Etilaminas/química , Leucina/análogos & derivados , Leucina/química , Modelos Moleculares
14.
PLoS Genet ; 6(11): e1001225, 2010 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-21124873

RESUMEN

In eukaryotes, 45S rRNA genes are arranged in tandem arrays in copy numbers ranging from several hundred to several thousand in plants. Although it is clear that not all copies are transcribed under normal growth conditions, the molecular basis controlling the expression of specific sets of rRNA genes remains unclear. Here, we report four major rRNA gene variants in Arabidopsis thaliana. Interestingly, while transcription of one of these rRNA variants is induced, the others are either repressed or remain unaltered in A. thaliana plants with a disrupted nucleolin-like protein gene (Atnuc-L1). Remarkably, the most highly represented rRNA gene variant, which is inactive in WT plants, is reactivated in Atnuc-L1 mutants. We show that accumulated pre-rRNAs originate from RNA Pol I transcription and are processed accurately. Moreover, we show that disruption of the AtNUC-L1 gene induces loss of symmetrical DNA methylation without affecting histone epigenetic marks at rRNA genes. Collectively, these data reveal a novel mechanism for rRNA gene transcriptional regulation in which the nucleolin protein plays a major role in controlling active and repressed rRNA gene variants in Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Metilación de ADN/genética , Regulación de la Expresión Génica de las Plantas , Genes de ARNr/genética , Mutación/genética , Fosfoproteínas/metabolismo , ARN de Planta/genética , Proteínas de Unión al ARN/metabolismo , Arabidopsis/enzimología , ADN Espaciador Ribosómico/genética , Perfilación de la Expresión Génica , Histonas/metabolismo , Región Organizadora del Nucléolo/genética , Nucleosomas/metabolismo , Unión Proteica , Procesamiento Proteico-Postraduccional , ARN Polimerasa I/metabolismo , ARN Ribosómico/genética , Secuencias Repetitivas de Ácidos Nucleicos/genética , Transcripción Genética , Nucleolina
15.
Front Psychol ; 14: 1042722, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37496791

RESUMEN

Introduction: Non-profit organizations (NPOs) are a complex working context whose main characteristic resides in the dichotomy between paid staff and volunteers. Despite its benefits for goal achievement, this circumstance can be also a challenge, for both groups' interaction, for their comprehension of their own role and to HR management. The aim of this study was to explore factors that may contribute to promote job satisfaction among NPOs' members. Methods: Combining two different data analyses, serial multiple mediation analyses and cluster analyses, first we analyze whether there are differences between paid staff and volunteers in perceived intrapersonal conflict and performance and its effect on job satisfaction, and second, we analyze whether there is an additional profiles distribution that reflects more adequately the reality of NPOs, despite the formal roles that coexist in these organizations (paid staff and volunteers). Results: Results confirm that paid staff and volunteers differ on their perceived job satisfaction level, with volunteers being more satisfied. This relationship is serially mediated by role conflict, role ambiguity, and performance. Another characteristic of the NPOs is that the dichotomy between paid staff and volunteers does not capture well the reality of the labor relations between members of both groups and the organization. To explore this phenomenon, we perform a cluster analysis based on paid staff and volunteers' perceptions. Cluster analyses demonstrate the existence of three rather homogenous profiles. Discussion: Additionally, practical implications for HR management in NPOs and future research lines to understand this organizational context dynamics are also discussed.

16.
Ultrason Sonochem ; 99: 106550, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37562345

RESUMEN

To solve low mass transfer in photocatalytic technology for water treatment, the combination of photoactive nanoparticles with highly adsorptive materials has been regarded as a successful approach. The optimization of photoactive particle coating in terms of dispersion on the surface of adsorbing support is the main key to reach a maximum synergism for pollutants removal. This study discusses the coating of as-prepared biomass based activated carbon by g-C3N4 using three routes, namely ball milling (AC-CN@BM), physical stirring (AC-CN@Phy) and ultrasonic assisted coating (AC-CN@US). The coating mechanisms by different processes were discussed using different characterization techniques. Ball milling based coating provides good g-C3N4 dispersion on the surface of AC, however, a partial degradation of g-C3N4 structure and a lower surface area were confirmed by FTIR, XRD and BET analysis. Physically designed sample shows a significant agglomeration of particles on the surface of AC. However, ultrasonic coating provides excellent distribution of g-C3N4 and high surface of the composite. In terms of photoactivity, AC-CN@BM exhibits the lowest adsorption and photocatalytic activity under solar light for the removal of ciprofloxacin. AC-CN@Phy showed medium performance, but less physical stability of g-C3N4 particles on AC, leading to their partial release. AC-CN@US showed the highest efficiency and stability after using; suggesting the good combination between g-C3N4 and AC, which in turn maximizes the removal of ciprofloxacin via Adsorb & shuttle process. The overall costs of composite, including the starting elements and the coating ultrasonic process are relatively low and green as compared to commonly reported routes.

17.
Sci Rep ; 13(1): 17847, 2023 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-37857696

RESUMEN

The environmental-friendly hydrothermal method has been carried out to synthesize Bi2WO6 and g-C3N4/PVP doped Bi2WO6 nanorods (NRs) by incorporating different concentrations of graphitic carbon nitride (g-C3N4) as well as a specified quantity of polyvinylpyrrolidone (PVP). Bi2WO6 doped with g-C3N4 provides structural and chemical stability, reduces charge carriers, degrades dyes, and, owing to lower bandgap energy, is effective for antibacterial, catalytic activity, and molecular docking analysis. The purpose of this research is the treatment of polluted water and to investigate the bactericidal behavior of a ternary system. The catalytic degradation was performed to remove the harmful rhodamine B (RhB) dye using NaBH4 in conjunction with prepared NRs. The specimen compound demonstrated antibacterial activity against Escherichia coli (E. coli) at both high and low concentrations. Higher doped specimens of g-C3N4/PVP-doped Bi2WO6 exhibited a significant improvement in efficient bactericidal potential against E. coli (4.55 mm inhibition zone). In silico experiments were carried out on enoyl-[acylcarrier-protein] reductase (FabI) and ß-lactamase enzyme for E. coli to assess the potential of Bi2WO6, PVP doped Bi2WO6, and g-C3N4/PVP-doped Bi2WO6 NRs as their inhibitors and to justify their possible mechanism of action.


Asunto(s)
Bismuto , Povidona , Simulación del Acoplamiento Molecular , Povidona/farmacología , Bismuto/química , Luz , Colorantes/farmacología , Escherichia coli , Antibacterianos/farmacología , Antibacterianos/química
18.
Chem Sci ; 14(47): 13908-13914, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-38075668

RESUMEN

Surface intermediate species and oxygen vacancy-assisted mechanism over CeO2 catalyst in the direct dimethyl carbonate (DMC) synthesis from carbon dioxide and methanol are suggested by means of transient spectroscopic methodologies in conjunction with multivariate spectral analysis. How the two reactants, i.e. CO2 and methanol, interact with the CeO2 surface and how they form decisive surface intermediates leading to DMC are unraveled by DFT-based molecular dynamics simulation by precise statistical sampling of various configurations of surface states and intermediates. The atomistic simulations and uncovered stability of different intermediate states perfectly explain the unique DMC formation profile experimentally observed upon transient operations, strongly supporting the proposed oxygen vacancy-assisted reaction mechanism.

20.
Front Chem ; 11: 1191849, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37228862

RESUMEN

In this study, MoO3 nanostructures were prepared, doped with various concentrations of graphene oxide (2 and 4% GO) and a fixed amount of polyvinylpyrrolidone (PVP) using the co-precipitation method. The motive of this study was to examine the catalytic and antimicrobial efficacy with evidential molecular docking analyses of GO/PVP-doped MoO3. GO and PVP were utilized as doping agents to reduce the exciton recombination rate of MoO3 by providing more active sites that increase the antibacterial activity of MoO3. The prepared binary dopant (GO and PVP)-dependent MoO3 was used as an effective antibacterial agent against Escherichia coli (E. coli). Notably, 4% GO/PVP-doped MoO3 showed good bactericidal potential against E. coli at higher concentrations in comparison to ciprofloxacin. Furthermore, in silico docking revealed the possible inhibitory impact of the synthesized nanocomposites on folate and fatty acid synthesis enzymes, dihydrofolate reductase and enoyl-[acyl carrier protein] reductase, respectively.

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