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1.
EMBO Rep ; 24(12): e57724, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-38277394

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells by first engaging its cellular receptor angiotensin converting enzyme 2 (ACE2) to induce conformational changes in the virus-encoded spike protein and fusion between the viral and target cell membranes. Here, we report that certain monoclonal neutralizing antibodies against distinct epitopic regions of the receptor-binding domain of the spike can replace ACE2 to serve as a receptor and efficiently support membrane fusion and viral infectivity in vitro. These receptor-like antibodies can function in the form of a complex of their soluble immunoglobulin G with Fc-gamma receptor I, a chimera of their antigen-binding fragment with the transmembrane domain of ACE2 or a membrane-bound B cell receptor, indicating that ACE2 and its specific interaction with the spike protein are dispensable for SARS-CoV-2 entry. These results suggest that antibody responses against SARS-CoV-2 may help expand the viral tropism to otherwise nonpermissive cell types with potential implications for viral transmission and pathogenesis.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Enzima Convertidora de Angiotensina 2 , Glicoproteína de la Espiga del Coronavirus/genética , Proteínas Portadoras/metabolismo , Células Cultivadas , Unión Proteica
2.
Small ; 20(15): e2304574, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38009795

RESUMEN

Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer-Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.

3.
Chem Soc Rev ; 52(21): 7602-7664, 2023 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-37830178

RESUMEN

Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated.

4.
J Am Chem Soc ; 145(14): 8052-8063, 2023 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-36994816

RESUMEN

Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metal-support interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of ∼186 m2 g-1) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (η10 at 351 mV; mass activity of 2209 mA mgCo-1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.

5.
J Am Chem Soc ; 144(29): 13254-13265, 2022 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-35796714

RESUMEN

Electrochemical CO2 reduction (ECR) with industrially relevant current densities, high product selectivity, and long-term stability has been a long-sought goal. Unfortunately, copper (Cu) catalysts for producing valuable multicarbon (C2+) products undergo structural and morphological changes under ECR conditions, especially at high current densities, resulting in a rapid decrease in product selectivity. Herein, we report a catalyst regeneration strategy, one that employs an electrolysis method comprising alternating "on" and "off" operating regimes, to increase the operating stability of a Cu catalyst. We find that it increases operating lifetime many times, maintaining ethylene selectivity ≥40% for at least 200 h of electrolysis in neutral pH media at a current density of 150 mA cm-2 using a flow cell. We also demonstrate ECR to ethylene at a current density of 1 A cm-2 with ethylene selectivity ≥40% using a three-dimensional Cu gas diffusion electrode, finding that this system under these conditions is rendered stable for greater than 36 h. This work illustrates that Cu-based catalysts, once they have entered into the state conventionally considered to possess degraded catalytic activity, may be recovered to deliver high C2+ selectivity. We present evidence that the combination of short periods of electrolysis, which minimizes the morphological changes during "on" segments, with the progressive chemical oxidation of Cu atoms on the catalyst surface during "off" segments, united with the added effects of washing the accumulated salt and decreasing the catholyte temperature prolong together the catalyst's operating lifetime.


Asunto(s)
Dióxido de Carbono , Etilenos , Dióxido de Carbono/química , Catálisis , Oxidación-Reducción , Regeneración
6.
J Gastroenterol Hepatol ; 37(3): 489-498, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34672022

RESUMEN

BACKGROUND AND AIM: Because acute infectious gastroenteritis may cause post-infection irritable bowel syndrome and functional dyspepsia and the severe acute respiratory syndrome coronavirus-2 affects gastrointestinal (GI) tract, coronavirus disease-19 (COVID-19) may cause post-infection-functional GI disorders (FGIDs). We prospectively studied the frequency and spectrum of post-infection-FGIDs among COVID-19 and historical healthy controls and the risk factors for its development. METHODS: Two hundred eighty patients with COVID-19 and 264 historical healthy controls were followed up at 1 and 3 months using translated validated Rome Questionnaires for the development of chronic bowel dysfunction (CBD), dyspeptic symptoms, and their overlap and at 6-month for IBS, uninvestigated dyspepsia (UD) and their overlap. Psychological comorbidity was studied using Rome III Psychosocial Alarm Questionnaire. RESULTS: At 1 and 3 months, 16 (5.7%), 16 (5.7%), 11 (3.9%), and 24 (8.6%), 6 (2.1%), 9 (3.2%) of COVID-19 patients developed CBD, dyspeptic symptoms, and their overlap, respectively; among healthy controls, none developed dyspeptic symptoms and one developed CBD at 3 months (P < 0.05). At 6 months, 15 (5.3%), 6 (2.1%), and 5 (1.8%) of the 280 COVID-19 patients developed IBS, UD, and IBS-UD overlap, respectively, and one healthy control developed IBS at 6 months (P < 0.05 for all except IBS-UD overlap). The risk factors for post-COVID-19 FGIDs at 6 months included symptoms (particularly GI), anosmia, ageusia, and presence of CBD, dyspeptic symptoms, or their overlap at 1 and 3 months and the psychological comorbidity. CONCLUSIONS: This is the first study showing COVID-19 led to post-COVID-19 FGIDs. Post-COVID-19 FGIDs may pose a significant economic, social, and healthcare burden to the world.


Asunto(s)
COVID-19 , Enfermedades Gastrointestinales , COVID-19/complicaciones , COVID-19/epidemiología , Estudios de Casos y Controles , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/virología , Humanos , Incidencia , Estudios Prospectivos , Factores de Riesgo , SARS-CoV-2
7.
Biochem Biophys Res Commun ; 555: 121-127, 2021 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-33813270

RESUMEN

The epidermal growth factor receptor extracellular domain III (EGFR-ECDIII) protein is a promising target of anti-cancer research, and its production in Escherichia coli would thus represent significant benefits. However, despite its moderate size (19 kDa), the expression of EGFR-ECDIII in E.coli is hampered by the presence of multiple cysteines producing misfolded proteins with incorrect S-S bonds. In our study, we show that a short 12-residue solubility enhancing peptide (SEP) tag containing nine arginines (C9R) attached at the C-terminus of EGFR-ECDIII reduces the inclusion body formation and increases the final yield by six times (20 mg/L). EGFR-ECDIII-C9R purified from the soluble fraction eluted as a sharp single RP-HPLC peak, suggesting a single S-S bond pairing. Biophysical characterization using circular dichroism, fluorescence, and light scattering confirmed its native-like properties together with reversible thermal denaturation. The binding activity of EGFR-ECDIII-C9R to anti-EGFR-VHH7D12, a single-domain antibody with specific binding to the ECDIII, was assessed by sandwich ELISA. Further, we produced anti-EGFR-ECDIII-C9R antisera in mouse models and anti-sera inhibited A431 cancer cells' growth. These results demonstrate that the SEP tag enables the rapid production of the multiple disulfide-bonded EGFR-ECDIII in E. coli having native-like biophysical properties and producing neutralizing antibodies.


Asunto(s)
Antineoplásicos Inmunológicos/farmacología , Receptores ErbB/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Animales , Antineoplásicos Inmunológicos/inmunología , Línea Celular Tumoral , Cromatografía de Fase Inversa , Dicroismo Circular , Ensayo de Inmunoadsorción Enzimática , Receptores ErbB/inmunología , Escherichia coli/genética , Femenino , Humanos , Sueros Inmunes , Ratones Endogámicos ICR , Tamaño de la Partícula , Conformación Proteica , Dominios Proteicos , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Solubilidad
8.
Chem Soc Rev ; 49(6): 1887-1931, 2020 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-32101197

RESUMEN

This review focuses on the discussion of the latest progress and remaining challenges in selected metal-free photocatalysts for hydrogen production. The scope of this review is limited to the metal-free elemental photocatalysts (i.e. B, C, P, S, Si, Se etc.), binary photocatalysts (i.e. BC3, B4C, CxNy, h-BN etc.) and their heterojunction, ternary photocatalysts (i.e. BCN) and their heterojunction, and different types of organic photocatalysts (i.e. linear, covalent organic frameworks, microporous polymer, covalent triazine frameworks etc.) and their heterostructures. Following a succinct depiction of the latest progress in hydrogen evolution on these photocatalysts, discussion has been extended to the potential strategies that are deemed necessary to attain high quantum efficiency and high solar-to-hydrogen (STH) conversion efficiency. Issues with reproducibility and the disputes in reporting the hydrogen evolution rate have been also discussed with recommendations to overcome them. A few key factors are highlighted that may facilitate the scalability of the photocatalyst from microscale to macroscale production in meeting the targeted 10% STH. This review is concluded with additional perspectives regarding future research in fundamental materials aspects of high efficiency photocatalysts followed by six open questions that may need to be resolved by forming a global hydrogen taskforce in order to translate bench-top research into large-scale production of hydrogen.

9.
Molecules ; 26(22)2021 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-34834053

RESUMEN

The electrochemical reduction of carbon dioxide (CO2ER) is amongst one the most promising technologies to reduce greenhouse gas emissions since carbon dioxide (CO2) can be converted to value-added products. Moreover, the possibility of using a renewable source of energy makes this process environmentally compelling. CO2ER in ionic liquids (ILs) has recently attracted attention due to its unique properties in reducing overpotential and raising faradaic efficiency. The current literature on CO2ER mainly reports on the effect of structures, physical and chemical interactions, acidity, and the electrode-electrolyte interface region on the reaction mechanism. However, in this work, new insights are presented for the CO2ER reaction mechanism that are based on the molecular interactions of the ILs and their physicochemical properties. This new insight will open possibilities for the utilization of new types of ionic liquids. Additionally, the roles of anions, cations, and the electrodes in the CO2ER reactions are also reviewed.

10.
Biochemistry ; 59(39): 3660-3668, 2020 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-32924442

RESUMEN

Protein amorphous aggregation has become the focus of great attention, as it can impair the ability of cells to function properly. Here, we evaluated the effects of three peptide tags, consisting of one, three, and five consecutive isoleucines attached at the C-terminus end of a simplified bovine pancreatic trypsin inhibitor (BPTI) variant, BPTI-19A, on the thermal stability and oligomerization by circular dichroism spectrometry and differential scanning calorimetry in detail. All of the BPTI-19A variants exhibited a reversible and apparently two-state thermal transition like BPTI-19A at pH 4.7. The thermal transition of the five-isoleucine-tagged variant showed clear protein-concentration dependence, where the apparent denaturation temperature decreased as the protein concentration increased. Quantitative analysis indicated that this phenomenon originated from the presence of reversibly oligomerized (RO) states at high temperatures. The results also illustrated that the thermodynamic stability difference between the native and the monomeric denatured state in all the proteins was destabilized by the hydrophobic tags and was well explained by the reverse hydrophobic effect due to the tags. The existence of the RO states was confirmed by both analytical ultracentrifugation and dynamic light scattering. This indicated that the five-isoleucine hydrophobic tag is strong enough to induce intermolecular hydrophobic contact among the denatured molecules leading to oligomerization, and even one- or three-isoleucine tags are effective enough to generate intramolecular hydrophobic contact, thus provoking denaturation through the reverse hydrophobic effect.


Asunto(s)
Aprotinina/química , Isoleucina/química , Agregado de Proteínas , Animales , Bovinos , Interacciones Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Péptidos/química , Multimerización de Proteína , Estabilidad Proteica
11.
Biochem Biophys Res Commun ; 508(4): 1043-1049, 2019 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-30551882

RESUMEN

ScFv is emerging as a therapeutic alternative to the full-length monoclonal antibodies due to its small size and low production cost, but its low solubility remains a limiting factor toward wider use. Here, we increased the solubility of an Anti-epidermal growth factor receptor ScFv (Anti-EGFR ScFv) by attaching, a short 12-residue solubility enhancing peptide (SEP) tag at its C terminus. We first estimated the solubility increase by running 500-ns Brownian dynamics (BD) simulations. We then experimentally evaluated the predictions by producing recombinant Anti-EGFR ScFv with and without a SEP tag (called C9R) in E. coli. At 20 °C, ∼85% of Anti-EGFR ScFv-C9R expressed in the soluble fraction, whereas all of the Anti-EGFR ScFv remained in the insoluble fraction. The total yield of Anti-EGFR ScFv-C9R was 17.15 mg which was ∼3 times higher than that of Anti-EGFR ScFv refolded from the insoluble fraction. Static and dynamic light scattering demonstrated the higher solubility of the purified Anti-EGFR ScFv-C9R, and Circular Dichroism (CD) indicated its high thermal stability, whereas the untagged protein aggregated at 37 °C and pH 6. Finally, the binding activity of Anti-EGFR ScFv-C9R to EGFR was confirmed by surface plasmon resonance (SPR). Altogether, these results illustrate the improved biophysical and biochemical characteristics of Anti-EGFR ScFv-C9R and emphasize the potentials of SEP-tags for enhancing the solubility of aggregation-prone antibody fragments.


Asunto(s)
Receptores ErbB/inmunología , Anticuerpos de Cadena Única/inmunología , Secuencia de Aminoácidos , Dispersión Dinámica de Luz , Receptores ErbB/química , Receptores ErbB/aislamiento & purificación , Proteínas Mutantes/genética , Proteínas Mutantes/aislamiento & purificación , Mutación/genética , Unión Proteica , Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/aislamiento & purificación , Solubilidad , Resonancia por Plasmón de Superficie
12.
J Am Chem Soc ; 140(11): 3833-3837, 2018 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-29504748

RESUMEN

Over a broad range of operating conditions, many CO2 electroreduction catalysts can maintain selectivity toward certain reduction products, leading to materials and surfaces being categorized according to their products; here we ask, is product selectivity truly a property of the catalyst? Silver is among the best electrocatalysts for CO in aqueous electrolytes, where it reaches near-unity selectivity. We consider the hydrogenations of the oxygen and carbon atoms via the two proton-coupled-electron-transfer processes as chief determinants of product selectivity; and find using density functional theory (DFT) that the hydronium (H3O+) intermediate plays a key role in the first oxygen hydrogenation step and lowers the activation energy barrier for CO formation. When this hydronium influence is removed, the activation energy barrier for oxygen hydrogenation increases significantly, and the barrier for carbon hydrogenation is reduced. These effects make the formate reaction pathway more favorable than CO. Experimentally, we then carry out CO2 reduction in highly concentrated potassium hydroxide (KOH), limiting the hydronium concentration in the aqueous electrolyte. The product selectivity of a silver catalyst switches from entirely CO under neutral conditions to over 50% formate in the alkaline environment. The simulated and experimentally observed selectivity shift provides new insights into the role of hydronium on CO2 electroreduction processes and the ability for electrolyte manipulation to directly influence transition state (TS) kinetics, altering favored CO2 reaction pathways. We argue that selectivity should be considered less of an intrinsic catalyst property, and rather a combined product of the catalyst and reaction environment.

13.
Am J Gastroenterol ; 113(9): 1363-1375, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30171215

RESUMEN

BACKGROUND: Postinfection irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD), though reported from the temperate countries, have not been studied in the tropics; PI-malabsorption syndrome (MAS), which mimics PI-IBS, is reported from the tropics. No report till date on PI-IBS excluded PI-MAS. We studied: (i) the frequency of continuing bowel dysfunction after acute gastroenteritis (AG), (ii) its predictors, and (iii) PI-MAS among patients with PI-IBS. METHODS: 345 consecutive subjects each, with AG and age- and gender-matched healthy controls were followed up 3-monthly for 12 months using a translated-validated questionnaire and functional gastrointestinal disorders (FGIDs) were diagnosed by Rome III criteria. Symptom duration >3 months but <6 months was diagnosed as chronic bowel dysfunction (CBD) and dyspeptic symptoms, respectively. MAS was diagnosed if 2/3 tests (D-xylose H2 breath test, Sudan III-stained stool microscopy, and duodenal histology) were abnormal. Fecal microbiological studies were performed in 245/345 (71%) patients. RESULTS: AG patients more often developed PI-IBS and PI-FD than controls (16.5 vs. 2.6% and 7.4 vs. 0.6%, respectively; p<0.001). Presence of FD was a risk factor for PI-IBS and IBS for PI-FD. On multivariate analysis, dyspeptic symptoms, CBD, and weight loss were the risk factors for PI-FGIDs. The frequency of PI-IBS following Vibrio cholera and other bacterial infection was comparable. Malabsorption was present among 2/23 (9%) patients with PI-IBS. CONCLUSION: FGIDs are common after AG; dyspeptic symptoms, CBD, and weight loss were risk factors for PI-FGIDs. Vibrio cholerae infection caused PI-FGID, which was never reported. About 9 % patients fulfilling the criteria for PI-IBS had PI-MAS.


Asunto(s)
Infecciones Bacterianas/complicaciones , Diarrea/complicaciones , Dispepsia/epidemiología , Gastroenteritis/complicaciones , Síndrome del Colon Irritable/epidemiología , Adulto , Bacterias/aislamiento & purificación , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/microbiología , Bangladesh/epidemiología , Estudios de Casos y Controles , Enfermedad Crónica/epidemiología , Diarrea/diagnóstico , Diarrea/microbiología , Dispepsia/diagnóstico , Dispepsia/etiología , Femenino , Estudios de Seguimiento , Gastroenteritis/diagnóstico , Gastroenteritis/microbiología , Humanos , Incidencia , Síndrome del Colon Irritable/diagnóstico , Síndrome del Colon Irritable/etiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios/estadística & datos numéricos , Pérdida de Peso , Adulto Joven
15.
Pak J Med Sci ; 31(5): 1283-5, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26649032

RESUMEN

Spontaneous echo contrast (SEC) and thrombus in enlarged left atrium (LA) are common in mitral valvular disease (MVD) and SEC is considered to be a prethrombotic condition. Reliable exclusion of LA thrombus is important before any definitive curative attempts like percutaneous transluminal mitral commissurotomy (PTMC), closed mitral commissurotomy (CMC) or innovative therapies like pulmonary vein isolation and percutaneous closure of the LA appendage. Echocardiography, particularly the transesophageal echocardiography (TEE) is considered to be the gold standard for the diagnosis and to exclude LA thrombus. However, LA thrombus may remain rarely undetected even by TEE potentially making the interventions a risky job. We present a case of mitral stenosis (MS) with giant LA where profuse, dense SEC masked the underlying thrombus in the LA cavity.

16.
Nano Lett ; 13(11): 5437-42, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24074440

RESUMEN

We have examined the carrier injection process of axial nanowire light-emitting diode (LED) structures and identified that poor carrier injection efficiency, due to the large surface recombination, is the primary cause for the extremely low output power of phosphor-free nanowire white LEDs. We have further developed InGaN/GaN/AlGaN dot-in-a-wire core-shell white LEDs on Si substrate, which can break the carrier injection efficiency bottleneck, leading to a massive enhancement in the output power. At room temperature, the devices can exhibit an output power of ~1.5 mW, which is more than 2 orders of magnitude stronger than nanowire LEDs without shell coverage. Additionally, such phosphor-free nanowire white LEDs can deliver an unprecedentedly high color rendering index of ~92-98 in both the warm and cool white regions, with the color rendering capability approaching that of an ideal light source, i.e. a blackbody.

17.
Heliyon ; 10(17): e36356, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39281540

RESUMEN

In the realm of healthcare, an imperative necessity for all, institutions are increasingly recognizing the advantages of adopting lean strategies to enhance performance. Lean implementation in healthcare can lead to significant improvements in efficiency, patient care, and overall institutional performance. This paper aims to assess the readiness levels for implementing lean practices in healthcare institutes in Bangladesh, employing a fuzzy logic approach. The construction of a conceptual model is grounded in literature review and expert opinions, incorporating critical enablers, criteria, and attributes identified from extensive research. Factors measured include leadership commitment, workforce capability, operational processes, technological infrastructure, and organizational culture, each pivotal in determining readiness for lean implementation. The fuzzy logic approach is particularly useful in this context due to its ability to handle uncertainty and imprecision, which are common in complex environments like healthcare. This methodology not only provides a clear picture of current capabilities but also highlights specific areas that need enhancement, paving the way for more targeted and effective lean interventions. Data sourced from consultations with experts in three prominent hospitals in Bangladesh forms the basis of the analysis, enabling a detailed examination of readiness levels. The model's application of fuzzy logic facilitates a comprehensive assessment, revealing 12 critical attributes across the hospitals that require attention. Interestingly, the evaluation identifies varying levels of readiness, with two hospitals demonstrating moderate readiness and one showing a lower level. This conceptual approach has significant potential to assist top management in healthcare companies by providing a structured framework to prioritize crucial areas for improvement. By accurately assessing readiness levels and pinpointing weaker aspects before implementing lean strategies, this study aims to transform the healthcare industry. Ultimately, its implementation has the potential to enhance organizational performance and elevate standards in patient care, contributing to improved healthcare delivery in Bangladesh and beyond.

18.
ChemSusChem ; 17(4): e202301425, 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-37922209

RESUMEN

Electrification of the chemical industry has been considered an enabler for energy transition on a massive scale. In this context, carbon monoxide electroreduction (COR) to produce multi-carbon (C2+ ) products is considered one of the forefront emerging technologies. The key challenge in COR comes from the excessive cation crossover to the cathode via electromigration and water diffusion, which limits CO availability and impedes product selectivity. Commercial anion exchange membrane (AEM) suppresses the electromigration of cations, however, suffers from water diffusion which facilitates cation crossover. Here, we tackled these problems emerging from cation crossover and water diffusion by directly depositing an ultrathin Nafion ionomer on the cathode (sputtered Cu) surface. Our approach enables full-cell energy efficiency of 21 % for converting CO into ethylene (C2 H4 ) at 100 mA/cm2 with over 200 hours of stable operation. We also exhibited record high energy efficiency for ethanol (C2 H5 OH) production with CO-to-C2 H5 OH electrolysis efficiency of 17 %. This approach to directly depositing ultrathin ionomer on the cathode to enhance system performance may benefit other electrochemical systems to overcome challenges associated with scalability, stability, and efficiency to produce high-value chemicals.

19.
Heliyon ; 10(2): e24317, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38298634

RESUMEN

This study endeavors to examine the validity of Wagner's Law, which has received considerable attention in recent years. We develop a panel dataset of 20 countries, taking five countries from each income group defined by the World Bank, for the 1991-2018 periods. Five different versions of the law are tested using this dataset. We add further depth to the model by involve the government's revenue and the volume of trade as independent variables. We inquire into the subsistence of cross-sectional dependence. To determine the order of integration, we conduct LLC, IPS, and CADF tests. The results show that the dataset has I (0) and I (1) series, and no series is found to be of I (2). Then we perform the panel ARDL test, and calculate PMG and DFE estimates. We use the Hausman test to choose among the estimates. In each version of the law, the error correction term indicates the presence of both long-term associations within the variables and an economic convergence process. However, we find no evidence to support the law for any version. Additionally, we conduct the panel cointegration tests, such as Westerlund, Pedroni and Kao. These cointegration tests generate results accordant with the ARDL findings.

20.
Health Sci Rep ; 7(9): e70024, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39210992

RESUMEN

Background: Depression, anxiety, and stress are the commonly encountered mental health conditions among medical students. Overseas environment may add additional burden to the existing environment. However, comparison of the rate and associated factors of depression, anxiety, stress among domestic and overseas students has not been attempted in Bangladesh. We aimed to assess the rate and associated factors of depression, anxiety, stress among domestic and overseas medical students in the country. Methods: This cross-sectional study was conducted among 360 undergraduate medical students in 2021. Data were collected by self-reporting instruments by a stratified random sampling method by the Depression, Anxiety, and Stress Scale-21 scale. Bivariable and multivariable binary logistic regression analyses were done by computing crude odds ratio and adjusted odds ratio with 95% confidence interval to identify the associated factors. Results: Among the 360 undergraduate medical students, 181 were domestic and 179 overseas ones. 44.8% of domestic students reported depressive symptoms, 45.3% reported anxiety symptoms, and 33.1% reported stress. On the other hand, half of overseas students experienced depression (50.3%) and anxiety (52.5%), and 41.3% experienced stress. Female medical students were found vulnerable for developing depression, anxiety, and stress than males. Conclusions: The study revealed higher rates of depression, anxiety, and stress among overseas undergraduate medical students enrolled in a private medical school of Bangladesh. Private medical college authorities could consider special services for overseas students to ensure adequate psychosocial support.

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