Positive Effect Research Articles

PLGA Nanoparticles as New Drug Delivery Systems in Leishmaniasis Chemotherapy: A Review of Current Practices.

Although leishmaniasis is one of the most common parasitic diseases, its traditional treatments suffer from some serious problems. To solve such issues, we can take advantage of the effective nanoparticle-based approaches to deliver anti-leishmanial agents into leishmania-infected macrophages either using passive targeting or using macrophagerelated receptors. Despite the high potential of nanotechnology, Liposomal Amphotericin B (AmBisome®) is the only FDA-approved nanoparticle-based anti-leishmanial therapy. In an effort to find more anti-leishmanial nano-drugs, this 2011-2021 review study aimed to investigate the in-vivo and in-vitro effectiveness of poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) in the delivery of some traditional anti-leishmanial drugs. Based on the results, PLGA-NPs could improve solubility, controlled release, trapping efficacy, bioavailability, selectivity, and mucosal penetration of the drugs, while they decreased resistance, dose/duration of administration and organotoxicity of the agents. However, none of these nano-formulations have been able to enter clinical trials so far. We summarized the data about the common problems of anti-leishmanial agents and the positive effects of various PLGA nano-formulations on reducing these drawbacks under both in-vitro and in-vivo conditions in three separate tables. Overall, this study proposes two AmB-loaded PLGA with a 99% reduction in parasite load as promising nanoparticles for further studies.

Improving Xenon-129 lung ventilation image SNR with deep-learning based image reconstruction.

To evaluate the feasibility and utility of a deep learning (DL)-based reconstruction for improving the SNR of hyperpolarized 129Xe lung ventilation MRI. 129Xe lung ventilation MRI data acquired from patients with asthma and/or chronic obstructive pulmonary disease (COPD) were retrospectively reconstructed with a commercial DL reconstruction pipeline at five different denoising levels. Quantitative imaging metrics of lung ventilation including ventilation defect percentage (VDP) and ventilation heterogeneity index (VHI) were compared between each set of DL-reconstructed images and alternative denoising strategies including: filtering, total variation denoising and higher-order singular value decomposition. Structural similarity between the denoised and original images was assessed. In a prospective study, the feasibility of using SNR gains from DL reconstruction to allow natural-abundance xenon MRI was evaluated in healthy volunteers. 129Xe ventilation image SNR was improved with DL reconstruction when compared with conventionally reconstructed images. In patients with asthma and/or COPD, DL-reconstructed images exhibited a slight positive bias in ventilation defect percentage (1.3% at 75% denoising) and ventilation heterogeneity index (˜1.4) when compared with conventionally reconstructed images. Additionally, DL-reconstructed images preserved structural similarity more effectively than data denoised using alternative approaches. DL reconstruction greatly improved image SNR (greater than threefold), to a level that 129Xe ventilation imaging using natural-abundance xenon appears feasible. DL-based image reconstruction significantly improves 129Xe ventilation image SNR, preserves structural similarity, and leads to a minor bias in ventilation metrics that can be attributed to differences in the image sharpness. This tool should help facilitate cost-effective 129Xe ventilation imaging with natural-abundance xenon in the future.

Investigating Tropical Cyclone Warm Core and Boundary Layer Structures with Constellation Observing System for Meteorology, Ionosphere, and Climate 2 Radio Occultation Data

The Constellation Observing System for Meteorology, Ionosphere, and Climate 2 (COSMIC-2) collects data covering latitudes primarily between 40 degrees north and south, providing abundant data for tropical cyclone (TC) research. The radio occultation data provide valuable information on the boundary layer. However, quality control of the data within the boundary layer remains a challenging issue. The aim of this study is to obtain a more accurate COSMIC-2 radio occultation (RO) dataset through quality control (QC) and use this dataset to validate warm core structures and explore the planetary boundary layer (PBL) structures of TCs. In this study, COSMIC-2 data are used to analyze the distribution of the relative local spectral width (LSW) and the confidence parameter characterizing the random error of the bending angle. An LSW less than 20% is set as a data QC threshold, and the warm core and PBL composite structures of TCs at three intensities in the Northwest Pacific Ocean are investigated. We reproduce the warm core intensity and warm core height characteristics of TCs. In the radial direction of the typhoon eyewall, the impact height of the PBL increases from 3.45 km to 4 km, with the tropopause ranging from 160 hPa to 100 hPa. At the bottom of the troposphere, the variations in the positive and negative bias between the RO-detected and background field bending angles correspond well to the PBL heights, and the variations in the positive bias between the RO-detected and background field refractivity reach 14%. This research provides an effective QC method and reveals that the bending angle is sensitive to the PBL height.

Why is there no negativity bias in evaluative conditioning? A cognitive-ecological answer.

Evaluative conditioning (EC) is the change of a conditioned stimulus's evaluation due to its pairing with an unconditioned stimulus (US). While learning typically shows negativity biases, we found no such biases in a reanalysis of meta-analytic EC data. We provide and test a cognitive-ecological answer for this lack of negativity bias. We assume that negativity effects follow from ecological differences in evaluative information's distributions (i.e., differential frequency). Accordingly, no negativity bias emerges because positive and negative information is equally frequent in most EC experiments. However, if negative (or positive) information is rare, we predict a negativity (positivity) bias. We tested this prediction in five preregistered experiments (three laboratory-based, N = 394, two online, N = 391). As predicted, if negative USs were rare, a negativity bias followed. However, if positive USs were rare, we also observed positivity biases in participants' conditioned stimulus evaluations. These data support a cognitive-ecological explanation of valence asymmetries and partially explain why EC experiments show no negativity bias: Typical EC designs do not reflect the ecological information structure that contributes to a negativity bias in the first place. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

COMPARATIVE CHARACTERISTICS OF METHODS FOR THE PREVENTION OF DENTAL CARIES IN CHILDREN OF EARLY CHILDHOOD

The high prevalence and intensity of early childhood caries in Ukraine and in the world indicate insuffi cient attention of practical dentistry to the prevention of dental caries in young children. The development of adapted prevention programs considering the risk factors for the development of the disease remains relevant.Aim of the study. To compare the eff ectiveness of methods of pre- and postnatal prevention of early childhood dental caries based on correction of the microbial environment of the oral cavity and macro- and microelemental nutrition.Material and methods. The work was carried out within the framework of the research work of the Department of Pediatric Dentistry of the Bukovinian State Medical University «Development of methods of prevention and treatment of major dental diseases in children, taking into account the risk factors of their development» (DR # 0121U110122). The prenatal method of dental caries prevention was applied to a group of pregnant women (30 persons) whose average age was (25,17±1,05) years. It included the use of Elevit Pronatal and Iodomarin 200, one tablet daily, starting from the second trimester ofpregnancy, and a course of local probiotic therapy with BioGaya ProDentis chewable tablets, used for 20 days in the second trimester of pregnancy and 20 days before delivery. As a method of postnatal prevention of dental caries in children, a preventive complex was used, including the use of the probiotic BioGaya ProDentis and the vitamin and mineral complex Supervit. The course lasted three weeks twice a year. The preventive complex was applied to a group of children aged 2-3 years. The number of children in the control group was 30. The mean age of the group was (2.51±1.30) years. The eff ectiveness of preventive measures was evaluated by the prevalence and intensity of caries of primary teeth («kpv» and «kpppv»), the state of oral hygiene (M. E. Kuzmina index), the content of phosphate ions, inorganic and ionized calcium in the oral fluid of children, the content of mutans streptococci in the oral cavity and the concentration of sIgA in the oral fl uid of children. Statistical processing of the study results was performed using standard methods of variation. The study complied with all bioethical norms (conclusion of the Bioethics Commission of the Bukovinian State Medical University No. 4 dated 15.12.2022).Results of the study. The use of preventive complexes for early childhood caries, based on the supplementation of macro- and microelements and the infl uence on the microbial landscape of the oral cavity, are eff ective methods of prevention of caries of temporary teeth in children, which is confi rmed by a decrease in the prevalence and intensity of dental caries in children in the dynamics of their observation. Prenatal measures are more eff ective in the prevention of early childhood caries in children, as they optimize the processes of primary mineralization of hard dental tissues and thus strengthen them, reducing the risk of dental caries. Postnatal use of the drugs has a slightly lower preventive eff ect on early childhood caries, while it has a positive eff ect on the processes of secondary mineralization of tooth enamel, as it was found that the level of phosphate ions in the oral fl uid of children under these conditions increased by 23.72 % (p<0.05), and the level of total calcium decreased by 15.84 % and its free fraction by 25.86 % (p<0.05).Conclusions. Our results suggest that both methods of prevention of early childhood caries are eff ective, but prenatal prophylaxis is clinically more eff ective with respect to the hard tissues of temporary teeth in children, due to its eff ect on the processes of primary mineralization of enamel. Postnatal prophylactic measures have a positive eff ect on the secondary mineralization of the hard tissues of temporary teeth and the primary mineralization of permanent teeth and will have a clinical result in the long term.

Increased memory accuracy of previous mood states in depressed patients in daily life.

Depression is characterized by a loss of positive and pronounced negative memory bias, which persists after remission. While theoretical accounts of depressive realism, emotional inertia, and mood-congruency substantiate the compelling evidence of weak positive memory in depression, they cannot fully explain negative memory bias in depression. We used Ecologically Momentary Assessments (EMA) of memory bias to provide insight into the accuracy and depression status-dependency of recall of previous positive and negative mood states. Currently- (n = 46), remitted- (n = 90), and never-depressed individuals (n = 55) provided positive mood and negative mood ratings (7x/day for six days), while also recalling their recent (i.e., previous prompt; 3x/day) or distal (i.e., one day lag; 1x/day) mood states. Currently depressed individuals displayed most accuracy and hence least bias in recall of both positive and negative mood; with accuracy in currently and remitted depressed individuals being independent of their current mood state. Conversely, mood at the time of recall significantly related to memory accuracy among never-depressed individuals with more negative mood, resulting in a depressotypic memory bias. Results are consistent with depressive realism and mood-congruency accounts, as well as with evidence for loss of positive memory bias (but not for negative memory bias) in depression.

Impact of post-deposition annealing on SiO2/SiC interfaces formed by plasma nitridation of the SiC surface and SiO2 deposition

Abstract We examined the impact of post-deposition annealing (PDA) on SiO2/SiC structures formed by plasma nitridation of the SiC surface followed by sputter deposition of SiO2. The interface state density near the conduction band edge of SiC was reduced from about 2×1012 to 1×1011 eV−1cm−2 as the CO2-PDA temperature increased from 1050 to 1250℃. In addition, the sample treated by CO2-PDA exhibited substantially higher immunity against positive gate bias stress than the standard NO nitridation. Our findings indicate that defect passivation by CO2-PDA plays a crucial role in improving the performance and reliability of SiC MOS devices formed by sputter-SiO2 deposition.

Harmonized Tubular Maximum Phosphate Reabsorption per Glomerular Filtration Rate (TmP/GFR) reporting in adults and children in Australia and New Zealand

Abstract Tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR) is a key diagnostic test for renal phosphate wasting. However, there is a lack of international consensus regarding the reporting of age-related reference intervals. The TmP/GFR Harmonization Working Group, formed by The Australasian Association for Clinical Biochemistry and Laboratory Medicine and The Australian and New Zealand Bone and Mineral Society, aimed to evaluate analytical differences amongst commercial creatinine and phosphate assays, harmonize age-specific cut-offs and compare the ANZBMS TmP/GFR online calculator with existing products. A total of 11 360 results from The Royal College of Pathologists of Australasia Quality Assurance Programs were analyzed to assess creatinine and phosphate assay performance amongst five In Vitro Diagnostic (IVD) companies. Ortho-Clinical Diagnostics analyzers had a positive bias of up to 32% for serum phosphate and up to 29% for TmP/GFR. The other IVD companies produced comparable results and are suitable for harmonized reference intervals. To date, the AACB-ANZBMS TmP/GFR online calculator is the only validated Isotope Dilution Mass Spectrometry-creatinine aligned tool which caters for both pediatric and adult individuals, providing automatic interpretive comments to aid clinicians managing patients with hypophosphatemia.

Varying Performance of Low-Cost Sensors During Seasonal Smog Events in Moravian-Silesian Region

Air pollution monitoring in industrial regions like Moravia-Silesia faces challenges due to complex environmental conditions. Low-cost sensors offer a promising, cost-effective alternative for supplementing data from regulatory-grade air quality monitoring stations. This study evaluates the accuracy and reliability of a prototype node containing low-cost sensors for carbon monoxide (CO) and particulate matter (PM), specifically tailored for the local conditions of the Moravian-Silesian Region during winter and spring periods. An analysis of the reference data observed during the winter evaluation period showed a strong positive correlation between PM, CO, and NO2 concentrations, attributable to common pollution sources under low ambient temperature conditions and increased local heating activity. The Sensirion SPS30 sensor exhibited high linearity during the winter period but showed a systematic positive bias in PM10 readings during Polish smog episodes, likely due to fine particles from domestic heating. Conversely, during Saharan dust storm episodes, the sensor showed a negative bias, underestimating PM10 levels due to the prevalence of coarse particles. Calibration adjustments, based on the PM1/PM10 ratio derived from Alphasense OPC-N3 data, were initially explored to reduce these biases. For the first time, this study quantifies the influence of particle size distribution on the SPS30 sensor’s response during smog episodes of varying origin, under the given local and seasonal conditions. In addition to sensor evaluation, we analyzed the potential use of data from the Copernicus Atmospheric Monitoring Service (CAMS) as an alternative to increasing sensor complexity. Our findings suggest that, with appropriate calibration, selected low-cost sensors can provide reliable data for monitoring air pollution episodes in the Moravian-Silesian Region and may also be used for future adjustments of CAMS model predictions.

Al modification layer method for enhancing InAlZnO transistors

In this work, a surface engineering method is proposed to boost electrical performance and stability of the InAlZnO (IAZO) transistors, of which an Al modification layer is deposited on surface of the IAZO channel layer. Through analysed by transmission electron microscope and X-ray photoelectron spectroscopy, the IAZO thin film with Al modification layer undergoes a reduction reaction to generate more oxygen vacancies. Hall effects measurement further demonstrates that IAZO thin films with Al modification layer exhibit higher carrier concentrations than the ones without Al modification layer. The IAZO transistors with Al modification layer exhibit better performance and stability, including a field-effect mobility of 4.36 cm2 V−1s−1 (an improvement of about three-fold), a small subthreshold swing of 105.23 mV/decade, a high on-to-off current ratio greater than 107, and a threshold voltage shift of less than 0.50 V under positive and negative gate bias stress. Moreover, the IAZO transistors with Al modification layer demonstrate high thermal stability under 400 °C for 120 min in air atmosphere. Based on this method, the IAZO inverters have been implemented with high voltage gain of 87.55 V/V. This surface engineering technology paves the way for application of high-performance oxide transistors for advanced monolithic three-dimensional integration.

A two-dimensional TaGe2P4–WSi2As4 van der Waals heterojunction: a near-ideal rectifier

Searching for suitable 2D metal-semiconductor interfaces to design high-performance Schottky diodes is essential for the continuous miniaturization of devices. Herein, by using the first-principles calculations, we propose a near-ideal two-dimensional van der Waals rectifier consisting of the monolayer TaGe2P4 metal and the WSi2As4 semiconductor with ultra-clean interface and free dangling bonds. The van der Waals heterojunction has a p-type Schottky contact at both the vertical and lateral interfaces. The Schottky barriers lead to the asymmetry of electronic transport under the positive and negative bias voltages, thus resulting in a remarkable rectification behavior. The rectifying properties can be improved by regulating the length of the semiconductor and the overlapping region, and an ultra-high rectification ratio of 107 is obtained at a low bias voltage. The origin of the rectification effect and the regulating mechanism are explained in terms of the projected local density of states, transmission eigenstates, potential drop, and transmission spectra. It is found that increasing the relative length of the semiconductive part in the device enlarges the width of the Schottky barrier, which largely reduces the reverse current dominated by the electron tunneling. At the same time, little affects the positive current and thus leads to a significant improvement in the rectification performance. These results suggest that the TaGe2P4–WSi2As4 van der Waals heterojunction has promising application as a near-ideal rectifier.

Assimilation of Satellite Albedo to Improve Simulations of Glacier Hydrology

ABSTRACTWildfires and heatwaves have recently affected the hydrological system in unprecedented ways due to climate change. In cold regions, these extremes cause rapid reductions in snow and ice albedo due to soot deposition and unseasonal melt. Snow and ice albedo dynamics control net shortwave radiation and the available energy for melt and runoff generation. Many albedo algorithms in hydrological models cannot accurately simulate albedo dynamics because they were developed or parameterised based on historical observations. Remotely sensed albedo data assimilation (DA) can potentially improve model performance by updating modelled albedo with observations. This study seeks to diagnose the effects of remotely sensed snow and ice albedo DA on the prediction of streamflow from glacierized basins during wildfires and heatwaves. Sentinel‐2 20‐m albedo estimates were assimilated into a glacio‐hydrological model created using the Cold Regions Hydrological Modelling Platform (CRHM) in two Canadian Rockies glacierized basins, Athabasca Glacier Research Basin (AGRB) and Peyto Glacier Research Basin (PGRB). The study was conducted in 2018 (wildfires), 2019 (soot/algae), 2020 (normal) and 2021 (heatwaves). DA was employed to assimilate albedo into CRHM to simulate streamflow and was compared to a control run (CTRL) using off‐the‐shelf albedo parameters. Albedo DA benefited streamflow predictions during wildfires for both basins, with a KGE coefficient improvement of 0.18 and 0.20 in AGRB and PGRB, respectively. Four‐year DA streamflow predictions were superior to CTRL in PGRB, but DA was slightly better in AGRB. DA was not beneficial to streamflow predictions during heatwaves. DA improved streamflow predictions by decreasing positive bias, showing that albedo DA can reveal unknown albedo and snowpack dynamics in remote glacier zones that are poorly simulated in models. These findings corroborate the power of observational tools to incorporate near real‐time information into hydrological models to better inform water managers of the streamflow response to wildfires and heatwaves.

Does agricultural cooperative membership improve farm productive performance? A meta‐regression analysis

AbstractIn this article, we provide a quantitative review of the literature on the effect of cooperative membership on farms productive performance. Based on a dataset composed of 332 estimates from 80 studies, our meta‐regression analysis suggests that the current literature suffers from a severe positive publication bias. After correcting this bias, the overall average effect of cooperative membership on farms' productive performance is positive and statistically significant, but its magnitude is small to negligible. Interestingly, we find that cooperative membership has a stronger effect on yield than on technical efficiency. We also explore how contextual variables and methodological choices affect the reported estimates in the literature.

Symmetrical choices and biased confidence during uncertain personality trait judgments.

While great methodological strides have been made in the area of decision making research, decisions that rely on subjective stimuli, such as personality traits, still pose a challenge for researchers, partly because it is difficult to define a standard of accuracy for such choices-they lack a "ground truth". In studies on value-based decisions, this same problem has been circumvented by comparing uncertain subjective decisions against a separately assessed judgment of value-a "standard". Here we apply this method in a task of verbal personality trait judgment, and show how a separately assessed standard judgment can be used to precisely control stimulus presentation and analyze subjective personality choices via the method of reverse correlation. Per trial, a series of quasi-randomly sampled adjectives was shown, which participants categorized as more descriptive of either themselves of another person well known to them. Participants also indicated their confidence in the response. Each trial's difficulty was controlled based on the previously assessed standard judgment. Analysis of the behavioral data shows several decision-general properties during these personality judgments, such as symmetrical choices, steeper choice functions for confident trials, and a positive evidence bias during confidence judgment. We discuss how these findings can shed light on the cognitive processes involved in personality perception. The task and results together may help bridge the gap between research on complex, social forms of judgment and findings on more basic decision processes.

Fabrication of an In-rich IGZO TFT by Co-sputtering of In2O3 and IGZO and Characterization of its Compensated Positive Bias Stress Properties

Fabrication of an In-rich IGZO TFT by Co-sputtering of In2O3 and IGZO and Characterization of its Compensated Positive Bias Stress Properties

Evaluation of Hurricane Analysis and Forecast System (HAFS) Error Statistics Stratified by Internal Structure and Environmental Metrics

Abstract This study quantifies tropical cyclone (TC) error statistics from the Hurricane Analysis and Forecast System (HAFS) across different environmental conditions (e.g., vertical wind shear) and inner core structural metrics. A particular focus is the evolution of poorly understood aspects of internal TC structure, including vortex tilt, and their impact on forecast errors. Although previous studies have demonstrated that vortex tilt, vertical wind shear, and precipitation processes impact TC intensity and track, this is the first known study to stratify these cooperative interactions to gain insights on their relationships with forecast errors. A three-year retrospective sample of forecasts in the North Atlantic basin from two HAFS configurations (-A and -B) demonstrates that TCs with larger tilt magnitudes have larger forecast track errors on average than smaller tilt TCs. Smaller tilt magnitudes have larger absolute intensity errors in short range forecasts, whereas larger tilt magnitudes tend to have larger negative intensity biases at medium range. TCs with a tilted vortex are shown to have both left of shear (maximizing DSL) and left of tilt oriented positional track biases. Furthermore, those cases with greater downshear biases tend to have more convection and larger positive intensity biases, highlighting the importance of the interplay between inner core characteristics and forecast errors.

Ultraviolet extinction correlation with 3D dust maps using white dwarfs

ABSTRACT Accurate astrometric and photometric measurements from Gaia have led to the construction of 3D dust extinction maps which can now be used for estimating the integrated extinctions of Galactic sources located within 5 kpc. These maps based on optical observations may not be reliable for use in the ultraviolet (UV) which is more sensitive to reddening. Past studies have focussed on studying UV extinction using main-sequence stars but lack comparison with 3D dust maps. White dwarfs with well-modelled hydrogen-dominated (DA) atmospheres provide an advantage over main-sequence stars affected by magnetic activity. In this work, we study the variation of UV extinction with 3D dust maps utilizing Hubble Space Telescope (HST) and Galaxy Evolution Explorer (GALEX) observations of DA white dwarfs located within 300 pc. We used HST COS spectroscopic data of 76 sightlines to calculate the optical extinction from Si ii column densities and validate our results with the kinematic model predictions of the local interstellar medium. Also, we combined GALEX and Gaia photometric observations of 1158 DA white dwarfs to study UV reddening by comparing observed and modelled colour–colour relations. We calculated GALEX non-linearity corrections and derived reddening coefficients [$R(NUV-G)=6.52\pm 1.53$ and $R(FUV-G)=6.04\pm 2.41$] considering their variations with optical extinction ($\rm{A_{V}}\lt 0.1$ mag), and found them to be in good agreement with known extinction laws. HST analysis suggests a positive bias of 0.01–0.02 mag in the optical extinction from 3D maps depending on the Galactic latitude. These results independently confirm the validity of 3D dust maps to de-redden the optical and UV observations of white dwarfs.

Can satellite products monitor solar brightening in Europe?

Satellite products provide the best way to monitor the solar radiation reaching the Earth’s surface on a global scale. However, their capability to monitor solar radiation trends needs to be constantly evaluated. This depends on their temporal stability and the accurate representation of all processes driving solar radiation. This study evaluates these aspects by comparing and cross-comparing different solar radiation products (ERA5, CAMS-RAD 4.6, SARAH-3, CLARA-A3, CERES-EBAF 4.2) against in-situ measurements over Europe.All products show a moderate positive bias over Europe but strong differences in their root mean squared deviation (RMSD) related to their different cloud transmittance models. Geostationary-based products (SARAH-3, CAMS-RAD 4.6) provide the smallest RMSD closely followed by CLARA-A3, whereas ERA5 shows a large RMSD due to random errors in cloud transmittance.All products show an increase in surface solar radiation, or brightening, over the last 40 years over Europe, but the magnitude of the trends and their spatiotemporal variability differ between products. Despite finding temporal inhomogeneities in some products, the different trends are mostly due to different aerosol modeling approaches implemented by each product. Both SARAH-3 (+2.3 W/m2/decade, 2001–22) and CERES-EBAF 4.2 (+2.2 W/m2/decade, 2001–22) provide the most consistent trends compared to in-situ data, showing that after stabilizing in the late 2000s, brightening is particularly recovering in Western Europe. In-situ measurements show a reduction of aerosol optical depth from 2001 to 2022 that has been accentuated in the last 10 years, particularly in Western Europe. This would be consistent with the hypothesis that brightening recovery is driven by an aerosol reduction, though other analyses suggest that clouds also play a role in this recovery. More work is needed to understand the contribution of aerosols to solar radiation trends and the exact aerosol effects represented by each solar radiation product.

Impact of bias stress and endurance switching on electrical characteristics of polycrystalline ZnO-TFTs with Al2O3 gate dielectric

Abstract This study experimentally investigates electrical characteristics and degradation phenomena in polycrystalline zinc oxide thin-film transistors (ZnO-TFTs). ZnO-TFTs with Al2O3 gate dielectric, Al-doped ZnO (AZO) source–drain contacts, and AZO gate electrode are fabricated using remote plasma-enhanced atomic layer deposition at a maximum process temperature of 190 °C. We employ positive bias stress (PBS), negative bias stress (NBS), and endurance cycling measurements to evaluate the ZnO-TFT performance and examine carrier dynamics at the channel-dielectric interface and at grain boundaries in the polycrystalline channel. DC transfer measurements yield a threshold voltage of −5.95 V, a field-effect mobility of 53.5 cm2/(V∙s), a subthreshold swing of 136 mV dec−1, and an on-/off-current ratio above 109. PBS and NBS measurements, analysed using stretched-exponential fitting, reveal the dynamics of carrier trapping and de-trapping between the channel layer and the gate insulator. Carrier de-trapping time is 88 s under NBS at −15 V, compared to 1856 s trapping time under PBS at +15 V. Endurance tests across 109 cycles assess switching characteristics and temporal changes in ZnO-TFTs, focusing on threshold voltage and field-effect mobility. The threshold voltage shift observed during endurance cycling is similar to that of NBS due to the contrast in carrier trapping/de-trapping time. A measured mobility hysteresis of 19% between the forward and reverse measurement directions suggests grain boundary effects mediated by the applied gate bias. These findings underscore the electrical resilience of polycrystalline ZnO-TFTs and the aptitude for 3D heterogeneous integration applications.

The retrieval of neutral and positive autobiographical memories: a pilot study

Background Several studies have shown that the retrieval of positive memories may play a role in emotional regulation. However, it is unclear whether the effects of neutral and positive autobiographical memories differ. It is necessary to confirm whether genuinely neutral autobiographical memories can be retrieved without bias when prompted to recall neutral memories. Methods In this pilot study, using “home” and “study” as cue words, we investigated whether participants were able to retrieve appropriate autobiographical memories when asked to recall a limited number of neutral or positive memories. Results Although participants were asked to recall neutral autobiographical memories, they tended to recall positive memories. Conclusions Our results support the concept of positive memory bias and suggest that future work should consider combining neutral and positive autobiographical memories by asking participants to recall neutral–positive memories.