Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 397
Filtrar
1.
J Hazard Mater ; 421: 126693, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34396957

RESUMEN

Researchers interested in a paper's statement or aiming to acquire useful information from scientific papers rely heavily on references. Additionally, calculation accuracy is important for ensuring the technical soundness of scientific papers. However, inaccurate citations and calculations are common in scientific literature. A recently published paper in the Journal of Hazardous Materials reported a study on microplastics in groundwater and surface water from coastal south India (Tamil Nadu state) and the heavy metal adsorption capacities of different polymers. In this study, we identified critical calculation errors and incorrect reference citations.


Asunto(s)
Agua Subterránea , Metales Pesados , Contaminantes Químicos del Agua , Monitoreo del Ambiente , India , Microplásticos , Plásticos , Agua , Contaminantes Químicos del Agua/análisis
2.
ACS Chem Neurosci ; 12(22): 4361-4366, 2021 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-34735109

RESUMEN

Research on misfolding of tau proteins will help to better understand the formation process of neurofibrillary tangles, a hallmark of Alzheimer's disease. Mutation and histidine tautomeric effects have been considered the two most important inherent factors for tau protein misfolding. In current research, replica-exchange molecular dynamics (REMD) were performed to characterize the structural properties of the key fragment R3 of tau protein under the collective effects of P332L mutation and histidine tautomerism. Simulation results suggest that though the content ß-sheet of P332L R3 εδ isomer is slightly lower than that of the WT P332L R3 fragment, the total stable secondary structures including ß-sheet and helix of P332L R3 isomers are generally more prevalent than those of wild type R3, which may be the reason that P332L R3 has a higher aggregation tendency. Further analysis showed that the hydrogen bond networks are affected by the mutation and histidine tautomerism. Furthermore, the interactions between N-terminus and C-terminus play a crucial role in ß-hairpin formation in all isomers. The current study will contribute to revealing the collective effects of P332L and histidine tautomerism on the misfolding of tau proteins.


Asunto(s)
Enfermedad de Alzheimer , Proteínas tau , Enfermedad de Alzheimer/genética , Histidina/genética , Humanos , Mutación/genética , Ovillos Neurofibrilares/metabolismo , Conformación Proteica en Lámina beta , Proteínas tau/genética , Proteínas tau/metabolismo
3.
J Korean Med Sci ; 36(39): e280, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34636505

RESUMEN

BACKGROUND: Excess all-cause mortality is helpful to assess the full extent of the health impact, including direct and indirect deaths of coronavirus disease 2019 (COVID-19). The study aimed to estimate overall and regional excess all-cause mortality during the pandemic in Korea. METHODS: We obtained all-cause death data and population statistics from January 2010 to December 2020. The expected mortality in 2020 was estimated using a quasi-Poisson regression model. The model included death year, seasonal variation, cold wave (January), average death counts in the previous month, and population. Excess mortality was defined as the difference between the observed mortality and the expected mortality. Regions were classified into three areas according to the numbers of COVID-19 cases. RESULTS: There was no annual excess all-cause mortality in 2020 at the national and regional level compared to the average death for the previous ten years. The observed mortality in 2020 was 582.9 per 100,000 people, and the expected mortality was 582.3 per 100,000 people (95% confidence interval, 568.3-596.7). However, we found monthly and regional variations depending on the waves of the COVID-19 pandemic in Korea. While the mortality in August, October, and November exceeded the expected range, the mortality in September was lower than the expected range. The months in which excess deaths were identified differed by region. CONCLUSION: Our results show that the mortality in 2020 was similar to the historical trend. However, in the era of the COVID-19 pandemic, it would be necessary to regularly investigate COVID-19-related mortality and determine its direct and indirect causes.


Asunto(s)
COVID-19/mortalidad , SARS-CoV-2 , Causas de Muerte , Humanos , República de Corea/epidemiología
4.
Artículo en Inglés | MEDLINE | ID: mdl-34682401

RESUMEN

This study aimed to assess the correlation between political ideologies, government trust, and COVID-19 vaccine hesitancy in South Korea during the COVID-19 pandemic. A cross-sectional survey was conducted among South Korea's general population and 1000 respondents (aged 18 years and older) were included. We used multivariate logistic regression models to identify the factors associated with vaccine hesitancy. Respondents who self-identified as liberal or held "no political opinion" had higher rates of vaccine hesitancy than conservative respondents. People's trust in the government's countermeasures was associated with vaccination. Respondents who had risk perceptions (affective and cognitive) of COVID-19 had lower rates of vaccine hesitancy. Perceptions that the vaccine was not safe and being aged 18-29, 30-39, or 40-49 were associated with a higher probability of vaccine hesitancy. This study found that even if vaccine safety and risk perceptions toward COVID-19 were adjusted, self-rated political ideologies and government trust was associated with COVID-19 vaccine hesitancy. More effort to communicate with those who are *liberal or "no political opinion", younger, and have lower level of trust in the government are required to dissolve vaccine hesitancy. Further studies should analyze the mechanism of COVID-19 vaccine uptake for effective herd immunity.


Asunto(s)
COVID-19 , Vacunas , Vacunas contra la COVID-19 , Estudios Transversales , Gobierno , Humanos , Pandemias , República de Corea , SARS-CoV-2 , Confianza
5.
JMIR Public Health Surveill ; 7(11): e31635, 2021 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-34653017

RESUMEN

BACKGROUND: The COVID-19 pandemic has radically shifted living practices, thereby influencing changes in the health status and behaviors of every person. OBJECTIVE: The aim of this study was to investigate the impact of COVID-19 on the self-reported health status and health behaviors along with any associated factors in adults in the Republic of Korea wherein no stringent lockdown measures were implemented during the pandemic. METHODS: We conducted a web-based self-reported survey from November 2020 to December 2020. The study participants (N=2097) were identified through quota sampling by age, sex, and geographical regions among residents aged 19 years or older in Korea. The survey collected information on basic demographics, changes in self-reported health status, and health behaviors during the COVID-19 pandemic. Self-reported health status and health behaviors were categorized into 3 groups: unchanged, improved, or worsened. A chi-square test and logistic regression analyses were conducted. RESULTS: With regard to changes in the self-reported health status, the majority (1478/2097, 70.5%) of the participants reported that their health was unchanged, while 20% (420/2097) of the participants reported having worser health after the COVID-19 outbreak. With regard to changes in health behaviors, the proportion of participants who increased tobacco consumption was similar to that of those who decreased tobacco consumption (110/545, 20.2% vs 106/545, 19.5%, respectively), while the proportion of those who decreased their drinking frequency was more than twice as many as those who increased their drinking frequency (578/1603, 36.1% vs 270/1603, 16.8%, respectively). Further, those who decreased their exercising frequency were more than those who increased their exercising frequency (333/823, 15.9% vs 211/823, 10%, respectively). The factor that had the greatest influence on lifestyle was age. In the subgroup analysis, the group aged 20-29 years had the highest number of individuals with both a worsened (100/377, 26.5%) and an improved (218/377, 15.7%) health status. Further, individuals aged 20-29 years had greater odds of increased smoking (6.44, 95% CI 2.15-19.32), increased alcohol use (4.64, 95% CI 2.60-8.28), and decreased moderate or higher intensity aerobic exercise (3.39, 95% CI 1.82-6.33) compared to individuals aged 60 years and older. Younger adults showed deteriorated health behaviors, while older adults showed improved health behaviors. CONCLUSIONS: The health status and the behavior of the majority of the Koreans were not found to be heavily affected by the COVID-19 outbreak. However, in some cases, changes in health status or health behavior were identified. This study highlighted that some groups were overwhelmingly affected by COVID-19 compared to others. Certain groups reported experiencing both worsening and improving health, while other groups reported unchanged health status. Age was the most influential factor for behavior change; in particular, the younger generation's negative health behaviors need more attention in terms of public health. As COVID-19 prolongs, public health interventions for vulnerable groups may be needed.

6.
Yonsei Med J ; 62(10): 943-947, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34558874

RESUMEN

PURPOSE: This study aimed to investigate the association between autism spectrum disorder (ASD) diagnosis and mortality among children using the data from a large-scale national cohort of Korean infants and children. We also explored the association between hearing impairment detected during early infancy and mortality. MATERIALS AND METHODS: We performed a retrospective cohort study using the nationwide claims data of the Republic of Korea. Children born between 2007 and 2014 (n=3598904) were followed up until 2020. Cox proportional hazard models were used to examine the association between ASD diagnosis and mortality among children. Then, in order to evaluate the association between hearing impairment and mortality, Cox proportional hazard models were built using the responses related to hearing impairment asked during the first health screening (at age 4-6 months). RESULTS: Of the 3598904 children born between 2007 and 2014, 32878 children (0.9%) were diagnosed with ASD until the end of 2020. We identified that ASD diagnosis was associated with higher mortality among children [hazard ratio (HR)=2.5, 95% confidence interval (CI): 2.2-2.9]. This association was stronger among girls (HR=4.8, 95% CI: 3.9-5.8) compared to boys (HR=1.9, 95% CI: 1.6-2.2). We found that hearing impairment detected during infancy was associated with higher mortality among children with ASD diagnosis. CONCLUSION: ASD diagnosis was associated with higher mortality among Korean children. This association was stronger in girls than in boys. Hearing impairment detected during infancy was also associated with higher mortality among children diagnosed with ASD.


Asunto(s)
Trastorno del Espectro Autista , Trastorno del Espectro Autista/epidemiología , Niño , Estudios de Cohortes , Femenino , Humanos , Lactante , Masculino , Modelos de Riesgos Proporcionales , República de Corea/epidemiología , Estudios Retrospectivos
7.
Chem Sci ; 12(29): 10054-10062, 2021 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-34377399

RESUMEN

Precise detection of cellular senescence may allow its role in biological systems to be evaluated more effectively, while supporting studies of therapeutic candidates designed to evade its detrimental effect on physical function. We report here studies of α-l-fucosidase (α-fuc) as a biomarker for cellular senescence and the development of an α-fuc-responsive aggregation induced emission (AIE) probe, termed QM-NHαfuc designed to complement more conventional probes based on ß-galactosidase (ß-gal). Using QM-NHαfuc, the onset of replicative-, reactive oxygen species (ROS)-, ultraviolet A (UVA)-, and drug-induced senescence could be probed effectively. QM-NHαfuc also proved capable of identifying senescent cells lacking ß-gal expression. The non-invasive real-time senescence tracking provided by QM-NHαfuc was validated in an in vivo senescence model. The results presented in this study lead us to suggest that the QM-NHαfuc could emerge as a useful tool for investigating senescence processes in biological systems.

8.
ACS Chem Neurosci ; 12(17): 3203-3213, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34382391

RESUMEN

The aggregation and structural conversion of normal prion peptide (PrPC) into the pathogenic scrapie form (PrPSc), which can act as a seed to enhance prion amyloid fiber formation, is believed to be a crucial event in prionopathies. Previous research suggests that the prion monomer may play an important role in oligomer generation during disease pathogenesis. In the present study, extensive replica-exchange molecular dynamics (REMD) simulations were conducted to explore the conformational characteristics of the huPrP (125-160) monomer under the histidine tautomerism effect. Investigating the structural characteristics and fibrilization process is challenging because two histidine tautomers [Nε2-H (ε) and Nδ1-H (δ)] can occur in the open neutral state. Molecular dynamics (MD) simulation outcomes have shown that the toxic εδ and δδ isomer (containing several and broader local minima) had the highest α-helix structures, with contents of 21.11% and 21.01%, respectively, and may have a strong influence on the organizational behavior of a monomeric prion. The amino acids aspartate 20 (D20)-asparagine 29 (N29) and isoleucine 15 (I15)-histidine 16 (H16), D20-arginine 27 (R27) as well as N29 formed α-helix with the highest probabilities in the δδ and εδ isomer, accordingly. On the basis of our findings, we propose the histidine tautomerization hypothesis as a new prion accumulation mechanism, which may exist to induce the formation of prion accumulates. Overall, our tautomerism hypothesis constitutes a promising perspective for enhancing understanding of prion disease pathobiology and may help in the design of a good inhibitor.


Asunto(s)
Priones , Scrapie , Amiloide , Animales , Histidina , Simulación de Dinámica Molecular , Ovinos
9.
Yonsei Med J ; 62(9): 850-857, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34427072

RESUMEN

PURPOSE: During the COVID-19 pandemic, Korea has temporarily expanded coverage of teleconsultation to ensure access to essential health services. As a preliminary study, we investigated service utilization patterns and the characteristics of doctors and patients involved in these temporary teleconsultation services. MATERIALS AND METHODS: Using national health insurance claims data from February 23, 2020 to June 30, 2020 from the Health Insurance Review and Assessment Service, 228269875 cases were identified. Among them, 567390 cases that received teleconsultation services were included in our study. We performed descriptive analyses according to the types of healthcare institutions. RESULTS: In total, 6193 healthcare institutions provided teleconsultation. Of these, 5466 (88.3%) were clinics. Physicians providing teleconsultations were most likely to be doctors of internal medicine (34.0%) or pediatricians (7.0%) and based in the Seoul Metropolitan area (30.4%). In terms of patients undergoing teleconsultation, the most common major disease categories treated were circulatory system diseases (I00-I99). In a detailed analysis, hypertensive diseases (I10-I15) were the most common diagnoses, with a total of 88726 cases (15.6%), followed by diabetes mellitus at 60298 cases (10.6%). The proportion of Medical Aid recipients receiving teleconsultations was higher (9.5%) than other socioeconomic groups. Among all participants, 356622 cases (84.6%) were from a return visit, and 108838 cases (19.2%) received teleconsultation services without being prescribed drugs. CONCLUSION: Temporarily allowed teleconsultation services were provided mostly to the following patients: 1) those scheduled for revisitation, 2) those with chronic diseases, and 3) those living in pandemic hotspots.


Asunto(s)
COVID-19 , Consulta Remota , Humanos , Pandemias , Calidad de la Atención de Salud , SARS-CoV-2
10.
Talanta ; 233: 122552, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34215055

RESUMEN

In this work, a fire-new "signal-off" type photoelectrochemical (PEC) immunosensor based on bismuth sulfide/iodine doped bismuth oxychloride (Bi2S3/I:BiOCl) heterostructure as a platform and Au nanoparticles loaded hollow CoSnO3 nanoboxes (Au NPs@CoSnO3) as quenching label was designed, for sensitive detection of CYFRA 21-1. The I:BiOCl with flower-like structure could supply high specific surface area for loading nanometer materials. Then, Bi2S3 was formed in-situ by S2- adsorption on the surface of I:BiOCl by dangling bond of Bi3+, but did not change the flower-like structure of I:BiOCl. Then, n-type Bi2S3 and p-type I:BiOCl heterostructure showed good photoelectric behavior by providing an additional electric field to accelerate electron-hole separation. Furthermore, the production process of the heterostructure was simple, fast, low temperature, and without complex raw materials. The Au NPs@CoSnO3 with good photocatalytic activity could strongly compete with Bi2S3/I:BiOCl for electron donor of ascorbic acid (AA). Meanwhile, the CoSnO3 with hollow structure made the quenching effect more significant by the light-scattering effect that enhanced the light absorption capacity and shorten distance of carrier transport. Under optimal conditions, this proposed strategy displayed the low detection limit of 30 fg/mL, with a high linearity range from 100 fg/mL to 100 ng/mL for tumor markers CYFRA 21-1. Simultaneously, it also exhibited excellent specificity and acceptable stability, which might provide a new perspective for the fabrication of other PEC immunosensors with heterostructure simple synthesis and hollow materials.


Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , Antígenos de Neoplasias , Técnicas Electroquímicas , Oro , Inmunoensayo , Queratina-19 , Límite de Detección
11.
Chemosphere ; 284: 131376, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34229894

RESUMEN

This paper discusses some critical weak points and mistakes identified in the original paper. The authors disregarded the importance of field blanks, sampling equipment, and well specifications for proper quality assurance and control. Beneficial field practices guarantee highly reliable results of laboratory analysis for microplastics. In addition, polymer type (chemical composition) and shape (form) are different classification criteria, but the authors mixed these in their description. The distribution and transport of microplastics should be properly understood, along with a knowledge of groundwater flow conditions, such as flow direction and velocity, in the study area.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Microplásticos , Plásticos , Instalaciones de Eliminación de Residuos , Contaminantes Químicos del Agua/análisis
12.
Sci Rep ; 11(1): 13632, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-34211020

RESUMEN

We report unique observations from drilling and hydraulic stimulation at a depth of approximately 4.3 km in two Enhanced Geothermal System (EGS) wells at the Pohang EGS site, South Korea. We surveyed drilling logs and hydraulic stimulation data, simulated pore pressure diffusion around the fault delineated by seismic and drilling log analyses, conducted acoustic image logging through the EGS wells, observed significant water level drops (740 m) in one of the two EGS wells, and obtained hydrochemical and isotopic variation data in conjunction with the microbial community characteristics of the two EGS wells. We discuss the hydraulic and hydrochemical responses of formation pore water to a few key seismic events near the hypocenter. We focused on how the geochemistry of water that flowed back from the geothermal wells changed in association with key seismic events. These were (1) a swarm of small earthquakes that occurred when a significant circulation mud loss occurred during well drilling, (2) the MW 3.2 earthquake during hydraulic stimulation, and (3) the MW 5.5 main shock two months after the end of hydraulic stimulation. This study highlights the value of real-time monitoring and water chemistry analysis, in addition to seismic monitoring during EGS operation.

13.
ACS Chem Neurosci ; 12(14): 2705-2711, 2021 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-34240598

RESUMEN

As an intrinsic origin cause, histidine behaviors play a critical role in protein misfolding processes. Generally, the English (H6R) mutation will disrupt H6 interactions. However, the structural properties of Aß40 H6R and Aß42 H6R under the complex influence of a histidine tautomeric effect and an H6R mutation remain unclear. Therefore, we performed a replica exchange molecular dynamics simulation to unveil such structural properties. Our result showed that the H6R substitute could promote the generation of ß-sheet structures in comparison to the wild type. Three ß-strand structure properties were observed in Aß40 (rδδ), Aß42 (rεε), Aß42 (rεδ), and Aß42 (rδδ) with ß-sheet contents of 47.5%, 37.2%, 46.9%, and 38.6%, respectively, and the dominant conformational properties of Aß40 (rδδ), Aß42 (rεε), Aß42 (rεδ), and Aß42 (rδδ) had top conformational states of 86.0%, 73.2%, 67.0%, and 56.5%, respectively. Further analysis confirmed that R6 had different mechanisms for controlling the conformational features in Aß40 H6R and Aß42 H6R. In the Aß40 systems, H14 H-bond networks played a critical role in controlling the structural properties. However, in the Aß42 systems, R6 was more important because it was directly involved in the ß-strand formation and maintained the ß-sheet between the N-terminus and the central hydrophobic core region. Our current study helps to elucidate the histidine tautomeric behaviors in H6R mutations, which will present opportunities to understand the correlation between with/without H6 and the Aß40/Aß42 H6R misfolding mechanisms.


Asunto(s)
Enfermedad de Alzheimer , Histidina , Péptidos beta-Amiloides/genética , Histidina/genética , Humanos , Mutación/genética , Fragmentos de Péptidos/genética
14.
Int J Biol Macromol ; 184: 887-897, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-34153362

RESUMEN

Aggregated amyloid ß-peptide (Aß) in small oligomeric forms inside the brain causes synaptic function disruption and the development of Alzheimer's disease (AD). Histidine is an important amino acid that may lead to structural changes. Aß42 monomer chain includes 3 histidine residues that considering two ε and δ tautomers 8 isomers, including (εεε) and (εδδ) could be formed. Molecular dynamics simulation on homodimerization of (εεε) (the most common type of tautomers) and (εδδ) tautomers with different initial configurations using monomer chains from our previous work were performed to uncover the tautomeric behavior of histidine on Aß42 aggregation in a physiological pH which is still largely unknown and impossible to observe experimentally. We found a higher propensity of forming ß-sheet in (εδδ) homodimers and specifically in a greater amount from Aß42 than from Aß40. A smaller amount of ß-sheet formation was observed for (εεε) homodimers compared with (εδδ). Additionally, interactions in (εδδ) homodimers may indicate the importance of the hydrophobic core and C-/N-terminals during oligomerization. Our findings indicate the important role of the tautomeric effect of histidine and (εδδ) homodimers at the early stage of Aß aggregation.


Asunto(s)
Péptidos beta-Amiloides/química , Histidina/química , Fragmentos de Péptidos/química , Humanos , Modelos Moleculares , Simulación de Dinámica Molecular , Agregado de Proteínas , Conformación Proteica en Lámina beta , Multimerización de Proteína
15.
Int J Qual Health Care ; 33(2)2021 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-33961032

RESUMEN

BACKGROUND: Healthcare quality assessment is being conducted in many countries. Although improving health equity is one of the major objectives of medical quality assessment, it is not clear whether different socio-economic statuses show the same health outcomes even in the same medical quality hospitals. No study has directly compared the health outcomes of different socio-economic statuses in the same hospitals nationwide. OBJECTIVE: To determine whether the mortality rate of acute stroke patients differs according to socioeconomic status. METHODS: This study was a retrospective, observational study of patients who were subject to acute stroke quality assessment in 2013. A total of 10 399 stroke cases were included in the study. When evaluating the mortality rate, the researchers analysed 10 228 cases, after excluding 171 cases that were measured twice for the same person. The levels of socio-economic status were divided according to the use of medical benefits, either National Health Insurance (NHI) for general population or Medical Aid (MA) for the vulnerable. The primary outcomes measured according to socio-economic status were in-hospital mortality rate and 1-year follow-up mortality rate of stroke patients. The secondary outcome was the composite performance score. RESULTS: MA recipients had a higher in-hospital mortality rate (12.5 vs. 8.3%, P < 0.001) and 1-year follow-up mortality rate (14.9 vs. 10.8%, P < 0.001) than NHI subscribers. MA recipients had slightly lower scores than NHI subscribers (83.2 vs. 84.4, P = 0.02). In hospitals of the same grade, MA recipients had lower performance scores than NHI subscribers, although the difference was not statistically significant. CONCLUSIONS: There is a difference in mortality and healthcare performance according to socio-economic status in stroke patients in Korea. Efforts to improve equity are needed, including the development and monitoring of equality indicators and developing policies for healthcare equity.


Asunto(s)
Disparidades en Atención de Salud , Garantía de la Calidad de Atención de Salud , Calidad de la Atención de Salud , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular/terapia , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Equidad en Salud , Humanos , Masculino , Persona de Mediana Edad , República de Corea/epidemiología , Estudios Retrospectivos , Clase Social , Accidente Cerebrovascular/mortalidad
16.
ACS Chem Neurosci ; 12(11): 1983-1988, 2021 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-33978396

RESUMEN

Self-assembly of hyperphosphorylated tau proteins into neurofibrillary tangles (NFT) is a hallmark of Alzheimer's disease. Previous studies suggest that the tau monomer may play an important role in NFTs formation in two general categories: inert (Mi) monomer and seed-competent (Ms) monomer. In the current study, replica-exchange molecular dynamics (REMD) were performed to investigate the effect of histidine tautomerism on the structures of a key fragment (R3) of tau protein and the transformation between different conformations. Based on the simulation results, we propose the histidine tautomerism hypothesis for tau protein misfolding. Histidine tautomerism greatly expands the conformational library, which triggers the emergence of conformations with higher aggregation tendency. Moreover, the conversions existing in both isomers and conformations may cause protein misfolding to occur more readily.


Asunto(s)
Enfermedad de Alzheimer , Proteínas tau , Histidina , Humanos , Simulación de Dinámica Molecular , Ovillos Neurofibrilares/metabolismo , Proteínas tau/metabolismo
17.
Nanotechnology ; 32(33)2021 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-33915525

RESUMEN

Monoclinic scheelite bismuth vanadate is an efficient photocatalyst for water splitting. In this paper, we perform DFT + Ucalculations to investigate the structural, electronic, and optical properties, water adsorption and the oxygen evolution reaction processes on BiVO4(001) and BiVO4(110) surfaces in acidic medium both in the gas and solution (water) phases. The structural, electronic, optical, and water adsorption properties reveal that BiVO4(001) surface is energetically more stable than BiVO4(110) surface in vacuum. On other hand, the water oxidation mechanisms reveal that BiVO4(110) surface in water and in strained form in vacuum is energetically more stable than BiVO4(001) surface in water and in strained form in vacuum bothU = 0 and 2.1 V. The free energy of adsorption for all systems atU = 2.1 V reduce about 2 times than that atU = 0 V. Such analyzes provide important insights into the role of different facets on BiVO4surface for photocatalytic reactions.

18.
Phys Chem Chem Phys ; 23(17): 10475-10486, 2021 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-33899866

RESUMEN

The accumulation of ΔK280 tau mutant resulting in neurotoxic oligomeric aggregates is an important but yet mysterious procedure in Alzheimer's disease (AD) development. Recently, we proposed a histidine tautomerization hypothesis of tau fibrillogenesis for the pathobiology of AD and other neuro diseases. However, the influence of neutral histidine tautomeric states on tau mutation is still unclear. Herein, we performed replica-exchange molecular dynamics (REMD) simulations to characterize structural features as well as the mode of toxic action of the ΔK280 tau mutant in the presence of histidine tautomerism. Molecular dynamics (MD) simulation results show that the δε tautomeric isomer (having a distinct global energy minimum) had the highest ß-sheet structure, which adopts a sheet-rich conformer and may have significant influence on the structural behaviors of ΔK280 tau monomers. Furthermore, clustering, residual contact map, mobility and structural analysis exhibited that the presence of ß-strand interactions between stable lysine 8 (K8)-asparagine 13 (N13) and valine 39 (V39)-tyrosine 43 (Y43) residues plus K31-histidine 32 (H32) and K8-N13 (strand-loop-strand [ß-meander] structure) helped δε to form toxic aggregates. Moreover, H299 played a more critical role in the conformational instability of the δε than H268. Overall, the results obtained from this study may be used to arrest neurodegeneration in ΔK280 tau mutation carriers as well as increase the understanding of AD-related tau pathogenesis and strengthen the histidine tautomerism hypothesis of misfolded peptide accumulation.


Asunto(s)
Histidina/metabolismo , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Proteínas tau/metabolismo , Enfermedad de Alzheimer , Histidina/química , Histidina/genética , Humanos , Polipéptido Amiloide de los Islotes Pancreáticos/química , Polipéptido Amiloide de los Islotes Pancreáticos/genética , Simulación de Dinámica Molecular , Mutación , Proteínas tau/química , Proteínas tau/genética
19.
J Toxicol Sci ; 46(3): 125-129, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33642518

RESUMEN

Cadmium (Cd) is a toxic heavy metal, long-term exposure to which causes renal damage associated with disruption in gene expression. Transcription factors whose activities were altered in the kidneys of mice exposed to Cd for 3 months were assessed using protein/DNA-binding assays. Female C57BL/6J mice were exposed to 300 ppm Cd in the diet for 3 months. Nuclear extracts of kidney were used for protein/DNA-binding assays. The concentration of Cd was approximately 100 ppm in mouse kidney, a level that did not induce renal toxicity. Among the 345 transcription factors evaluated, five transcription factors showed over a two-fold increase in their activities and 14 transcription factors showed a half-fold change in their activities after Cd exposure. These findings may provide new information about the causative transcription factors associated with Cd renal toxicity.


Asunto(s)
Cadmio/toxicidad , ADN/metabolismo , Expresión Génica/efectos de los fármacos , Riñón/diagnóstico por imagen , Riñón/metabolismo , Unión Proteica/efectos de los fármacos , Factores de Transcripción/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Femenino , Ratones Endogámicos C57BL , Factores de Tiempo , Factores de Transcripción/genética
20.
J Colloid Interface Sci ; 592: 440-447, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33711646

RESUMEN

The high cost and relative scarcity of platinum (Pt) restrict large-scale commercialization of fuel cells, which has spurred researchers to develop low-cost alternatives integrating with high hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) catalytic activity. Herein, we performed density functional theory (DFT) calculations to explore the electrocatalytic activity of graphyne nanotubes (GyNTs). Several GyNTs were found to be potential metal-free electrocatalysts, with both HER and ORR activity superior to Pt. Moreover, we revealed a linear relationship between the Gibbs free energy change of O2 adsorption (ΔGOOH) and binding energy of H adsorption (ΔEH), which could be attributed to the fact that both the CO bond of OOH adsorption and the CH bond of H adsorption are single bonds. Therefore, ΔEH is proposed as a general descriptor for the rational design of bifunctional graphyne materials toward HERs and ORRs. Our findings provide a simple strategy for the rational design of bifunctional materials.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...