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1.
J Clin Anesth ; 93: 111368, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38157663

RESUMEN

STUDY OBJECTIVE: Intraoperative electroencephalogram (EEG) patterns associated with postoperative delirium (POD) development have been studied, but the differences in EEG recordings between sevoflurane- and desflurane-induced anesthesia have not been clarified. We aimed to distinguish the EEG characteristics of sevoflurane and desflurane in relation to POD development. DESIGN AND PATIENTS: We collected frontal four-channel EEG data during the maintenance of anesthesia from 148 elderly patients who received sevoflurane (n = 77) or desflurane (n = 71); 30 patients were diagnosed with delirium postoperatively. The patients were divided into four subgroups based on anesthetics and delirium status: sevoflurane delirium (n = 17), sevoflurane non-delirium (n = 60), desflurane delirium (n = 13), and desflurane non-delirium (n = 58). We compared spectral power, coherence, and pairwise phase consistency (PPC) between sevoflurane and desflurane, and between non-delirium and delirium groups for each anesthetic. MAIN RESULTS: In patients without POD, the sevoflurane non-delirium group exhibited higher EEG spectral power across 8.5-35 Hz (99.5% CI bootstrap analysis) and higher PPC from alpha to gamma bands (p < 0.005) compared to the desflurane non-delirium group. Conversely, in patients with POD, no significant EEG differences were observed between the sevoflurane and desflurane delirium groups. For the sevoflurane-induced patients, the sevoflurane delirium group had significantly lower power within 7.5-31.5 Hz (99.5% CI bootstrap analysis), reduced coherence over 8.9-23.8 Hz (99.5% CI bootstrap analysis), and lower PPC values in the alpha band (p < 0.005) compared with the sevoflurane non-delirium group. For the desflurane-induced patients, there were no significant differences in the EEG patterns between delirium and non-delirium groups. CONCLUSIONS: In normal patients without POD, sevoflurane demonstrates a higher power spectrum and prefrontal connectivity than desflurane. Furthermore, reduced frontal alpha power, coherence, and connectivity of intraoperative EEG could be associated with an increased risk of POD. These intraoperative EEG characteristics associated with POD are more noticeable in sevoflurane-induced anesthesia than in desflurane-induced anesthesia.


Asunto(s)
Anestésicos por Inhalación , Delirio del Despertar , Isoflurano , Éteres Metílicos , Humanos , Anciano , Sevoflurano/efectos adversos , Desflurano/efectos adversos , Anestésicos por Inhalación/efectos adversos , Delirio del Despertar/inducido químicamente , Isoflurano/efectos adversos , Éteres Metílicos/efectos adversos , Electroencefalografía
3.
Nat Commun ; 14(1): 3087, 2023 05 29.
Artículo en Inglés | MEDLINE | ID: mdl-37248241

RESUMEN

To date, no herpesvirus has been shown to latently persist in fibroblastic cells. Here, we show that murine cytomegalovirus, a ß-herpesvirus, persists for the long term and across organs in PDGFRα-positive fibroblastic cells, with similar or higher genome loads than in the previously known sites of murine cytomegalovirus latency. Whereas murine cytomegalovirus gene transcription in PDGFRα-positive fibroblastic cells is almost completely silenced at 5 months post-infection, these cells give rise to reactivated virus ex vivo, arguing that they support latent murine cytomegalovirus infection. Notably, PDGFRα-positive fibroblastic cells also support productive virus replication during primary murine cytomegalovirus infection. Mechanistically, Stat1-deficiency promotes lytic infection but abolishes latent persistence of murine cytomegalovirus in PDGFRα-positive fibroblastic cells in vivo. In sum, fibroblastic cells have a dual role as a site of lytic murine cytomegalovirus replication and a reservoir of latent murine cytomegalovirus in vivo and STAT1 is required for murine cytomegalovirus latent persistence in vivo.


Asunto(s)
Infecciones por Citomegalovirus , Muromegalovirus , Animales , Ratones , Citomegalovirus/genética , Latencia del Virus/genética , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas , Replicación Viral , Fibroblastos , Factor de Transcripción STAT1/genética
4.
bioRxiv ; 2022 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-36482969

RESUMEN

Vaccines are central to controlling the coronavirus disease 2019 (COVID-19) pandemic but the durability of protection is limited for currently approved COVID-19 vaccines. Further, the emergence of variants of concern (VoCs) that evade immune recognition has reduced vaccine effectiveness, compounding the problem. Here, we show that a single dose of a murine cytomegalovirus (MCMV)-based vaccine, which expresses the spike (S) protein of the virus circulating early in the pandemic (MCMVS), protects highly susceptible K18-hACE2 mice from clinical symptoms and death upon challenge with a lethal dose of D614G SARS-CoV-2. Moreover, MCMVS vaccination controlled two immune-evading VoCs, the Beta (B.1.135) and the Omicron (BA.1) variants in BALB/c mice, and S-specific immunity was maintained for at least 5 months after immunization, where neutralizing titers against all tested VoCs were higher at 5-months than at 1-month post-vaccination. Thus, cytomegalovirus (CMV)-based vector vaccines might allow for long-term protection against COVID-19.

5.
Sci Rep ; 12(1): 19858, 2022 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-36400804

RESUMEN

SARS-CoV-2 variants accumulating immune escape mutations provide a significant risk to vaccine-induced protection against infection. The novel variant of concern (VoC) Omicron BA.1 and its sub-lineages have the largest number of amino acid alterations in its Spike protein to date. Thus, they may efficiently escape recognition by neutralizing antibodies, allowing breakthrough infections in convalescent and vaccinated individuals in particular in those who have only received a primary immunization scheme. We analyzed neutralization activity of sera from individuals after vaccination with all mRNA-, vector- or heterologous immunization schemes currently available in Europe by in vitro neutralization assay at peak response towards SARS-CoV-2 B.1, Omicron sub-lineages BA.1, BA.2, BA.2.12.1, BA.3, BA.4/5, Beta and Delta pseudotypes and also provide longitudinal follow-up data from BNT162b2 vaccinees. All vaccines apart from Ad26.CoV2.S showed high levels of responder rates (96-100%) towards the SARS-CoV-2 B.1 isolate, and minor to moderate reductions in neutralizing Beta and Delta VoC pseudotypes. The novel Omicron variant and its sub-lineages had the biggest impact, both in terms of response rates and neutralization titers. Only mRNA-1273 showed a 100% response rate to Omicron BA.1 and induced the highest level of neutralizing antibody titers, followed by heterologous prime-boost approaches. Homologous BNT162b2 vaccination, vector-based AZD1222 and Ad26.CoV2.S performed less well with peak responder rates of 48%, 56% and 9%, respectively. However, Omicron responder rates in BNT162b2 recipients were maintained in our six month longitudinal follow-up indicating that individuals with cross-protection against Omicron maintain it over time. Overall, our data strongly argue for booster doses in individuals who were previously vaccinated with BNT162b2, or a vector-based primary immunization scheme.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Pruebas de Neutralización , Anticuerpos Antivirales , Vacunas contra la COVID-19 , ARN Mensajero , Ad26COVS1 , Vacuna BNT162 , COVID-19/prevención & control , ChAdOx1 nCoV-19 , Vacunación
6.
Nat Commun ; 13(1): 3966, 2022 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-35803932

RESUMEN

Understanding the mechanisms and impact of booster vaccinations are essential in the design and delivery of vaccination programs. Here we show that a three dose regimen of a synthetic peptide vaccine elicits an accruing CD8+ T cell response against one SARS-CoV-2 Spike epitope. We see protection against lethal SARS-CoV-2 infection in the K18-hACE2 transgenic mouse model in the absence of neutralizing antibodies, but two dose approaches are insufficient to confer protection. The third vaccine dose of the single T cell epitope peptide results in superior generation of effector-memory T cells and tissue-resident memory T cells, and these tertiary vaccine-specific CD8+ T cells are characterized by enhanced polyfunctional cytokine production. Moreover, fate mapping shows that a substantial fraction of the tertiary CD8+ effector-memory T cells develop from re-migrated tissue-resident memory T cells. Thus, repeated booster vaccinations quantitatively and qualitatively improve the CD8+ T cell response leading to protection against otherwise lethal SARS-CoV-2 infection.


Asunto(s)
COVID-19 , Epítopos de Linfocito T , Animales , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Linfocitos T CD8-positivos , COVID-19/prevención & control , Modelos Animales de Enfermedad , Memoria Inmunológica , Ratones , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Vacunación , Vacunas Sintéticas
7.
J Virol ; 96(5): e0218621, 2022 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-35019723

RESUMEN

Recent emergence of SARS-CoV-1 variants demonstrates the potential of this virus for targeted evolution, despite its overall genomic stability. Here we show the dynamics and the mechanisms behind the rapid adaptation of SARS-CoV-2 to growth in Vero E6 cells. The selective advantage for growth in Vero E6 cells is due to increased cleavage efficiency by cathepsins at the mutated S1/S2 site. S1/S2 site also constitutes a heparan sulfate (HS) binding motif that influenced virus growth in Vero E6 cells, but HS antagonist did not inhibit virus adaptation in these cells. The entry of Vero E6-adapted virus into human cells is defective because the mutated spike variants are poorly processed by furin or TMPRSS2. Minor subpopulation that lack the furin cleavage motif in the spike protein rapidly become dominant upon passaging through Vero E6 cells, but wild type sequences are maintained at low percentage in the virus swarm and mediate a rapid reverse adaptation if the virus is passaged again on TMPRSS2+ human cells. Our data show that the spike protein of SARS-CoV-2 can rapidly adapt itself to available proteases and argue for deep sequence surveillance to identify the emergence of novel variants. IMPORTANCE Recently emerging SARS-CoV-2 variants B.1.1.7 (alpha variant), B.1.617.2 (delta variant), and B.1.1.529 (omicron variant) harbor spike mutations and have been linked to increased virus pathogenesis. The emergence of these novel variants highlights coronavirus adaptation and evolution potential, despite the stable consensus genotype of clinical isolates. We show that subdominant variants maintained in the virus population enable the virus to rapidly adapt to selection pressure. Although these adaptations lead to genotype change, the change is not absolute and genomes with original genotype are maintained in the virus swarm. Thus, our results imply that the relative stability of SARS-CoV-2 in numerous independent clinical isolates belies its potential for rapid adaptation to new conditions.


Asunto(s)
COVID-19/metabolismo , Furina/metabolismo , SARS-CoV-2/fisiología , Serina Endopeptidasas/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Adaptación Fisiológica , Animales , COVID-19/genética , COVID-19/virología , Chlorocebus aethiops , Efecto Citopatogénico Viral , Furina/genética , Células HEK293 , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mutación , SARS-CoV-2/genética , Serina Endopeptidasas/genética , Glicoproteína de la Espiga del Coronavirus/genética , Células Vero , Replicación Viral
8.
Cell Mol Immunol ; 19(2): 234-244, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34992275

RESUMEN

Global pandemics caused by influenza or coronaviruses cause severe disruptions to public health and lead to high morbidity and mortality. There remains a medical need for vaccines against these pathogens. CMV (cytomegalovirus) is a ß-herpesvirus that induces uniquely robust immune responses in which remarkably large populations of antigen-specific CD8+ T cells are maintained for a lifetime. Hence, CMV has been proposed and investigated as a novel vaccine vector for expressing antigenic peptides or proteins to elicit protective cellular immune responses against numerous pathogens. We generated two recombinant murine CMV (MCMV) vaccine vectors expressing hemagglutinin (HA) of influenza A virus (MCMVHA) or the spike protein of severe acute respiratory syndrome coronavirus 2 (MCMVS). A single injection of MCMVs expressing either viral protein induced potent neutralizing antibody responses, which strengthened over time. Importantly, MCMVHA-vaccinated mice were protected from illness following challenge with the influenza virus, and we excluded that this protection was due to the effects of memory T cells. Conclusively, we show here that MCMV vectors induce not only long-term cellular immunity but also humoral responses that provide long-term immune protection against clinically relevant respiratory pathogens.


Asunto(s)
Vacunas contra la COVID-19/inmunología , COVID-19/prevención & control , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Inmunidad Humoral , Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Infecciones por Orthomyxoviridae/prevención & control , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunación/métodos , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , COVID-19/virología , Chlorocebus aethiops , Citomegalovirus/inmunología , Perros , Femenino , Células HEK293 , Humanos , Inmunidad Celular , Células de Riñón Canino Madin Darby , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Infecciones por Orthomyxoviridae/virología , Células Vero
9.
Ecol Appl ; 31(8): e02459, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34582603

RESUMEN

Forests are critically important for the provision of ecosystem services. The Sacramento Mountains of New Mexico, USA, are a hotspot for conservation management and the Mescalero Apache Tribe's homeland. The multiple ecosystem services and functions and its high vulnerability to changes in climate conditions make their forests of ecological, cultural, and social importance. We used data from the Mescalero Apache Tribal Lands (MATL) Continuous Forest Inventory over 30 yr to analyze changes in the structure and composition of ecosystems as well as trends in ecosystem services. Many provisioning, regulating, cultural, and supporting services were shared among the MATL ecosystems and were tied to foundational species dominance, which could serve as a reliable indicator of ecosystem functioning. Our analysis indicates that the MATL are in an ongoing transition from conifer forests to woodlands with declines in two foundation species, quaking aspen and ponderosa pine, linked to past forest management and changing climate. In addition, we detected a decrease in species richness and tree size variability, amplifying the risk of forest loss in a rapid climatic change. Continuous permanent plots located on a dense grid (1 × 1 km) such as the ones monitored by the Bureau of Indian Affairs are the most detailed data available to estimate forests multiresource transitions over time. Native lands across the USA could serve as the leading edge of detecting decadal-scale forest changes and tracking climate impacts.


Asunto(s)
Ecosistema , Tracheophyta , Cambio Climático , Bosques , Árboles
10.
PLoS One ; 16(8): e0255622, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34339474

RESUMEN

The SARS-CoV-2 pandemic is a major global threat that sparked global research efforts. Pre-clinical and biochemical SARS-CoV-2 studies firstly rely on cell culture experiments where the importance of choosing an appropriate cell culture model is often underestimated. We here present a bottom-up approach to identify suitable permissive cancer cell lines for drug screening and virus research. Human cancer cell lines were screened for the SARS-CoV-2 cellular entry factors ACE2 and TMPRSS2 based on RNA-seq data of the Cancer Cell Line Encyclopedia (CCLE). However, experimentally testing permissiveness towards SARS-CoV-2 infection, we found limited correlation between receptor expression and permissiveness. This underlines that permissiveness of cells towards viral infection is determined not only by the presence of entry receptors but is defined by the availability of cellular resources, intrinsic immunity, and apoptosis. Aside from established cell culture infection models CACO-2 and CALU-3, three highly permissive human cell lines, colon cancer cell lines CL-14 and CL-40 and the breast cancer cell line CAL-51 and several low permissive cell lines were identified. Cell lines were characterised in more detail offering a broader choice of non-overexpression in vitro infection models to the scientific community. For some cell lines a truncated ACE2 mRNA and missense variants in TMPRSS2 might hint at disturbed host susceptibility towards viral entry.


Asunto(s)
COVID-19/virología , Receptores Virales , SARS-CoV-2/fisiología , Internalización del Virus , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/metabolismo , Línea Celular Tumoral , Humanos , Receptores Virales/genética , Receptores Virales/metabolismo , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo
11.
Workplace Health Saf ; : 21650799211031233, 2021 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-34344236

RESUMEN

BACKGROUND: Type II (customer-on-worker) workplace violence (WPV) against nurses and its underreporting are ongoing safety and health challenges in health care. The COVID-19 pandemic has strained patients and nurses and, in turn, may have increased WPV. The purpose of this cross-sectional study was to describe and compare a sample of nurses' reported prevalence of Type II WPV and their reporting of these events during the pandemic. METHODS: Data from an online survey of registered nurses (N = 373) working in hospitals were included. Prevalence was calculated for physical violence and verbal abuse, and their reporting of these events, including the experience of violence between nurses who did and did not care for patients with COVID-19. FINDINGS: Overall, 44.4% and 67.8% of the nurses reported experiencing physical violence and verbal abuse, respectively, between February and May/June 2020. Nurses who provided care for patients with COVID-19 experienced more physical violence (adjusted odds ratio [aOR] = 2.18, 95% confidence interval [CI] = [1.30, 3.67]) and verbal abuse (aOR = 2.10, 95% CI = [1.22, 3.61]) than nurses who did not care for these patients. One in 10 nurses felt reporting the incident was more difficult during the pandemic. CONCLUSION/APPLICATION TO PRACTICE: A significant proportion of nurses who cared for patients with COVID-19 experienced more physical violence and verbal abuse, and more difficulty in reporting to management. As the pandemic continues, health care organizations need to recognize that workers may be at an elevated risk for experiencing WPV and may be less likely to report, resulting in an urgent need for prevention efforts on their part.

12.
Cell Rep ; 36(4): 109433, 2021 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-34273271

RESUMEN

The novel betacoronavirus severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) causes a form of severe pneumonia disease called coronavirus disease 2019 (COVID-19). To develop human neutralizing anti-SARS-CoV-2 antibodies, antibody gene libraries from convalescent COVID-19 patients were constructed and recombinant antibody fragments (scFv) against the receptor-binding domain (RBD) of the spike protein were selected by phage display. The antibody STE90-C11 shows a subnanometer IC50 in a plaque-based live SARS-CoV-2 neutralization assay. The in vivo efficacy of the antibody is demonstrated in the Syrian hamster and in the human angiotensin-converting enzyme 2 (hACE2) mice model. The crystal structure of STE90-C11 Fab in complex with SARS-CoV-2-RBD is solved at 2.0 Å resolution showing that the antibody binds at the same region as ACE2 to RBD. The binding and inhibition of STE90-C11 is not blocked by many known emerging RBD mutations. STE90-C11-derived human IgG1 with FcγR-silenced Fc (COR-101) is undergoing Phase Ib/II clinical trials for the treatment of moderate to severe COVID-19.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , SARS-CoV-2/patogenicidad , Glicoproteína de la Espiga del Coronavirus/genética , COVID-19/virología , Humanos , Mutación/genética , Peptidil-Dipeptidasa A/metabolismo , Unión Proteica , Dominios Proteicos/genética , Glicoproteína de la Espiga del Coronavirus/inmunología
13.
ACS Appl Mater Interfaces ; 13(16): 19016-19022, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33861077

RESUMEN

When thickness-dependent carrier mobility is coupled with Thomas-Fermi screening and interlayer resistance effects in two-dimensional (2D) multilayer materials, a conducting channel migrates from the bottom surface to the top surface under electrostatic bias conditions. However, various factors including (i) insufficient carrier density, (ii) atomically thin material thickness, and (iii) numerous oxide traps/defects considerably limit our deep understanding of the carrier transport mechanism in 2D multilayer materials. Herein, we report the restricted conducting channel migration in 2D multilayer ReS2 after a constant voltage stress of gate dielectrics is applied. At a given gate bias condition, a gradual increase in the drain bias enables a sensitive change in the interlayer resistance of ReS2, leading to a modification of the shape of the transconductance curves, and consequently, demonstrates the conducting channel migration along the thickness of ReS2 before the stress. Meanwhile, this distinct conduction feature disappears after stress, indicating the formation of additional oxide trap sites inside the gate dielectrics that degrade the carrier mobility and eventually restrict the channel migration. Our theoretical and experimental study based on the resistor network model and Thomas-Fermi charge screening theory provides further insights into the origins of channel migration and restriction in 2D multilayer devices.

14.
Nat Commun ; 12(1): 1577, 2021 03 11.
Artículo en Inglés | MEDLINE | ID: mdl-33707427

RESUMEN

COVID-19 is a severe acute respiratory disease caused by SARS-CoV-2, a new recently emerged sarbecovirus. This virus uses the human ACE2 enzyme as receptor for cell entry, recognizing it with the receptor binding domain (RBD) of the S1 subunit of the viral spike protein. We present the use of phage display to select anti-SARS-CoV-2 spike antibodies from the human naïve antibody gene libraries HAL9/10 and subsequent identification of 309 unique fully human antibodies against S1. 17 antibodies are binding to the RBD, showing inhibition of spike binding to cells expressing ACE2 as scFv-Fc and neutralize active SARS-CoV-2 virus infection of VeroE6 cells. The antibody STE73-2E9 is showing neutralization of active SARS-CoV-2 as IgG and is binding to the ACE2-RBD interface. Thus, universal libraries from healthy human donors offer the advantage that antibodies can be generated quickly and independent from the availability of material from recovering patients in a pandemic situation.


Asunto(s)
Enzima Convertidora de Angiotensina 2/inmunología , Anticuerpos Neutralizantes/genética , Anticuerpos Antivirales/genética , COVID-19/inmunología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Enzima Convertidora de Angiotensina 2/química , Animales , Anticuerpos Neutralizantes/aislamiento & purificación , Anticuerpos Antivirales/aislamiento & purificación , Afinidad de Anticuerpos , COVID-19/epidemiología , Línea Celular , Chlorocebus aethiops , Biblioteca de Genes , Voluntarios Sanos , Interacciones Microbiota-Huesped/inmunología , Humanos , Inmunoglobulina G/genética , Inmunoglobulina G/aislamiento & purificación , Modelos Moleculares , Mutación , Pruebas de Neutralización , Pandemias , Biblioteca de Péptidos , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/química , Células Vero
15.
ACS Appl Mater Interfaces ; 13(2): 2829-2835, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33410320

RESUMEN

Hot carrier injection (HCI), occurring when the horizontal electric field is strongly applied, usually affects the degradation of nanoelectronic devices. In addition, metal contacts play a significant role in nanoelectronic devices. In this study, Schottky contacts in multilayer tungsten diselenide (WSe2) field-effect transistors (FETs) by hot carrier injection (HCI), occurring when a high drain voltage is applied, is investigated. A small number of hot carriers with high energy reduces the Schottky barrier height and improves the performance of FETs effectively rather than damaging the channel. Thermal annealing at the end of the fabrication process increases device performance by causing interfacial reactions of the source/drain electrodes. HCI causes a significant enhancement in the local asymmetry, especially in the subthreshold region. The subthreshold swing (SS) of the thermally annealed FETs is significantly improved from 9.66 to 0.562 V dec-1 through the energy of HCI generated by a strong horizontal electric field. In addition, the contact resistances (RSD), also called series resistances, extracted by a four-probe measurement and a Y-function method were also improved by decreasing to a 10th through the energy of HCI. To understand the asymmetrical characteristics of the channel after the stress, we performed electrical analysis, electrostatic force microscopy (EFM), and Raman spectroscopy.

16.
Nanotechnology ; 32(16): 165202, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33302263

RESUMEN

Through time-dependent defect spectroscopy and low-frequency noise measurements, we investigate and characterize the differences of carrier trapping processes occurred by different interfaces (top/sidewall) of the gate-all-around silicon nanosheet field-effect transistor (GAA SiNS FET). In a GAA SiNS FET fabricated by the top-down process, the traps at the sidewall interface significantly affect the device performance as the width decreases. Compare to expectations, as the width of the device decreases, the subthreshold swing (SS) increases from 120 to 230 mV/dec, resulting in less gate controllability. In narrow-width devices, the effect of traps located at the sidewall interface is significantly dominant, and the 1/f 2 noise, also known as generation-recombination (G-R) noise, is clearly appeared with an increased time constant (τ i ). In addition, the probability density distributions for the normalized current fluctuations (ΔI D) show only one Gaussian in wide-width devices, whereas they are separated into four Gaussians with increased in narrow-width devices. Therefore, fitting is performed through the carrier number fluctuation-correlated with mobility fluctuations model that separately considered the effects of sidewall. In narrow-width GAA SiNS FETs, consequently, the extracted interface trap densities (N T ) distribution becomes more dominant, and the scattering parameter ([Formula: see text]) distribution increases by more than double.

17.
Nanoscale ; 12(29): 15888-15895, 2020 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-32697229

RESUMEN

The negative and positive aging effects of quantum dot (QD) light-emitting diodes (QLEDs) have received considerable attention in recent years and various analysis methods have been discussed. Here, we introduce a new approach to understand the aging effect of QLEDs, which is to diagnose the behavior of carriers and traps at interfaces between each layer of the QLEDs and inside the layers themselves. In particular, low-frequency noise (LFN) measurement and the analysis of current in the QLEDs were introduced to investigate the trapping/de-trapping behaviors of carriers in the defect states in the devices. A flicker noise was observed before the carriers are injected into the QD emitting layer, while the exciton generation-recombination (G-R) noise and shot noise were observed when the electrons were injected. A correlated noise, which is the correlated model of the trapping/de-trapping of the carriers near and/or inside the QDs and the exciton recombination, was also observed above the turn-on voltage. In addition, when the devices were aged with a constant current source, rapid increases in the luminance and external quantum efficiency (EQE) were observed for up to 50 h. After 100 h of the current aging, however, the devices were negatively aged with the reduced EQE. The LFN analysis results imply that the aging phenomena mainly depend on the trapping/de-trapping of carriers. In addition to the LFN analysis, we also investigated the current density-voltage-luminance and capacitance-voltage characteristics of the devices to clarify the aging behaviors in QLEDs.

18.
MethodsX ; 7: 100917, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32477895

RESUMEN

We extend the Actor-Centred Power framework to consider dimensions beyond the life of community natural resource management partnership initiatives by examining social forestry partnership projects in Indonesia. We do this by examining how power constellations realign across the temporal phases that operationalize project partnerships. We propose a sequential power analysis framework that examines power in three parts. The framework first proposes a method for historicizing actors into their power background. Second, we present mode for examining the arrival of a partnership scheme, which we call the power delivery phase. Third, we highlight approaches for examining the way power relations are adjusted, whether reinforced or reconfigured, by introducing an approach for examining programmatic outcomes of social forestry partnership schemes. This article thus provides broadly applicable but targeted guide for the researchers collecting data and seeking to make sense of power relations on community forest partnership schemes in various contexts. This framework is particularly useful for analysing equity and justice dimensions by highlighting who benefits and who loses.•Sequential Power Analysis (SPA) methodology is rooted in interest based and historical power framework.•SPA is consisted of three parts: power background, power delivery, and power adjustment•SPA framing provides a protocol for researchers to collect data.

19.
Sci Rep ; 10(1): 6192, 2020 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-32277117

RESUMEN

There have been few comparative studies using electroencephalogram (EEG) spectral characteristics during the induction of general anesthesia for cesarean section. This retrospective study investigated the differences in the depth of anesthesia through EEG analysis between propofol- and thiopental-induced anesthesia. We reviewed data of 42 patients undergoing cesarean section who received either thiopental (5 mg/kg) or propofol (2 mg/kg). EEG data were extracted from the bispectral index (BIS) monitor, and 10-second segments were selected from the following sections: 1) Stage I, BIS below 60 after induction; 2) Stage II, after intubation completion; 3) Stage III, end-tidal sevoflurane above 0 vol%. The risk of awareness was represented by the BIS and entropy measures. In Stage III, the thiopental group (n = 20) showed significantly higher BIS value than the propofol group (n = 22) (67.9 [18.66] vs 44.5 [20.63], respectively, p = 0.002). The thiopental group had decreased slow-delta oscillations and increased beta-oscillations as compared to the propofol group in Stages II and III (p < 0.05). BIS, spectral entropy, and Renyi permutation entropy were also higher in the thiopental group at Stages II and III (p < 0.05). In conclusion, frontal spectral EEG analysis demonstrated that propofol induction maintained a deeper anesthesia than thiopental in pregnant women.


Asunto(s)
Anestesia Obstétrica/métodos , Despertar Intraoperatorio/diagnóstico , Monitorización Neurofisiológica Intraoperatoria/estadística & datos numéricos , Propofol/administración & dosificación , Tiopental/administración & dosificación , Adulto , Anestesia Obstétrica/efectos adversos , Ritmo beta/efectos de los fármacos , Cesárea/efectos adversos , Ritmo Delta/efectos de los fármacos , Femenino , Humanos , Despertar Intraoperatorio/epidemiología , Despertar Intraoperatorio/etiología , Monitorización Neurofisiológica Intraoperatoria/métodos , Embarazo , Estudios Retrospectivos , Medición de Riesgo/métodos , Medición de Riesgo/estadística & datos numéricos
20.
Ecol Appl ; 29(6): e01944, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31267598

RESUMEN

Climate change affects all ecosystems but despite increasing recognition for the needs to integrate Indigenous knowledge with modern climate science, the epistemological differences between the two make it challenging. In this study, we present how Indigenous belief and knowledge system can frame the application of a modeling tool (Climate-Forest Vegetation Simulator). We focus on managing forest ecosystem services of the Diné (Navajo) Nation as a case study. Most Diné tribal members depend directly on the land for their livelihoods and cultural traditions. The forest plays a vital role in Diné livelihoods through social, cultural, spiritual, subsistence, and economic factors. We simulated forest dynamics over time under alternative climate change scenarios and management strategies to identify forest management strategies that will maintain future ecosystem services. We initialized the Climate-Forest Vegetation Simulator model with data from permanent plots and site-specific growth models under multiple management systems (no-management, thinning, burning, and assisted migration planting) and different climate scenarios (no-climate-change, RCP 4.5, RCP 6.0). Projections of climate change show average losses of basal area by over 65% by 2105, a shift in tree species composition to drier-adapted species, and a decrease in species diversity. While substantial forest loss was inevitable under the warming climate scenarios, the modeling framework allowed us to evaluate the management treatments, including planting, for conserving multiple tree species in mixed conifer forests, thus providing an anchor for biodiversity. We presented the modeling results and management implications and discuss how they can complement Diné kinship concepts. Our approach is a useful step for framing modern science with Indigenous Knowledge and for developing improved strategies to sustain natural resources and livelihoods.


Asunto(s)
Cambio Climático , Árboles , Biodiversidad , Ecosistema , Bosques
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