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1.
Micromachines (Basel) ; 15(7)2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-39064407

RESUMEN

Identifying underperforming photovoltaic (PV) modules is crucial to ensure optimal energy production and financial returns, as well as preventing potential safety hazards in case of severe damage. To this aim, current-voltage (I-V) curve tracing can be employed as in situ monitoring technique for the early detection of faults. In this paper, we introduce a novel low-cost, microcontroller-based I-V tracer for the diagnosis of individual PV modules. The tool features a unique power conditioning circuit, facilitating accurate data acquisition under static conditions as well as the even distribution of the measured points along the I-V curve. A specific active disconnecting circuit enables in situ and on-line measurement without interrupting the string power generation. The designed prototype is used to characterize a set of PV modules under real operating conditions. The measured I-V curves exhibit expected trends, with the measured data closely matching theoretical values and an estimated mean relative error less than 3%.

2.
Nanomaterials (Basel) ; 14(8)2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38668153

RESUMEN

In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states allows reconfigurability to obtain new operating modes at different frequency input signals. X-ray diffraction (XRD) analysis is performed on each layer, revealing a cubic structure for MnO and a hexagonal structure for ZnO:Zn with preferential growth in [111] and [002] directions, respectively. Scanning electron microscope (SEM) micrographs show that the surface of both materials is homogeneous and smooth. The thickness for each layer is determined to be approximately 106.3 nm for MnO, 119.3 nm for ZnO:Zn and 224.1 nm for the MnO/ZnO:Zn structure. An electrical characterisation with an oscilloscope and signal generator was carried out to obtain the time-response signals and current-voltage (I-V) curves, where no degradation is detected when changing frequencies within the range of 100 Hz to 1 MHz. An equivalent circuit is proposed to explain the effects in the interface. Measurements of switching speeds from high resistance state (HRS) to low resistance state (LRS) at approximately 17 ns, highlight the device's rapid adaptability, and an estimated switching ratio of approximately 2 × 104 indicates its efficiency as a memristive component. Finally, the MnO/ZnO:Zn heterojunction delivers states that are stable, repeatable, and reproducible, demonstrating how the interaction of the materials can be utilised in adaptive device applications by applying frequencies and internal states to create new and innovative design schematics, thus reducing the number of components/connections in a system for future sustainable electronics.

3.
Acta Anaesthesiol Scand ; 68(6): 726-736, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38481015

RESUMEN

BACKGROUND: Existing PK models of propofol include sparse data from very obese patients. The aim of this study was to develop a PK model based on standardised surgical conditions and spanning from normal-weight up to, and including, a high number of very obese patients. METHODS: Adult patients scheduled for laparoscopic cholecystectomy or bariatric surgery were studied. Anaesthesia was induced with propofol 2 mg/kg adjusted body weight over 2 min followed by 6 mg/kg/h adjusted body weight over 30 min. For the remainder of the operation anaesthesia was maintained with sevoflurane. Remifentanil was dosed according to clinical need. Eight arterial samples were drawn in a randomised block sampling regimen over a span of 24 h. Time-concentration data were analysed by population PK modelling using non-linear mixed-effects modelling. RESULTS: Four hundred and seventy four serum propofol concentrations were collected from 69 patients aged 19-60 years with a BMI 21.6-67.3 kg/m2. Twenty one patients had a BMI above 50 kg/m2. A 3-compartment PK model was produced wherein three different body weight descriptors and sex were included as covariates in the final model. Total body weight was found to be a covariate for clearance and Q3; lean body weight for V1, V2 and Q2; predicted normal weight for V3 and sex for V1. The fixed allometric exponent of 0.75 applied to all clearance parameters improved the performance of the model. Accuracy and precision were 1.4% and 21.7% respectively in post-hoc performance evaluation. CONCLUSION: We have developed a new PK model of propofol that is suitable for all adult weight classes. Specifically, it is based on data from an unprecedented number of individuals with very high BMI.


Asunto(s)
Anestésicos Intravenosos , Cirugía Bariátrica , Propofol , Humanos , Propofol/farmacocinética , Propofol/sangre , Adulto , Masculino , Femenino , Persona de Mediana Edad , Anestésicos Intravenosos/farmacocinética , Anestésicos Intravenosos/sangre , Adulto Joven , Obesidad Mórbida/cirugía , Índice de Masa Corporal , Colecistectomía Laparoscópica , Obesidad , Remifentanilo/farmacocinética , Modelos Biológicos , Peso Corporal
4.
Math Biosci Eng ; 21(2): 1899-1916, 2024 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-38454667

RESUMEN

We consider a quasi-one-dimensional Poisson-Nernst-Planck model with two cations having the same valances and one anion. Bikerman's local hard-sphere potential is included to account for ion size effects. Under some further restrictions on the boundary conditions of the two cations, we obtain approximations of the I-V (current-voltage) relations by treating the ion sizes as small parameters. Critical potentials are identified, which play critical roles in characterizing finite ion size effects on ionic flows. Nonlinear interplays between system parameters, such as boundary concentrations and diffusion coefficients, are analyzed. To provide more intuitive illustrations of our analytical results and better understanding of the dynamics of ionic flows through membrane channels, numerical simulations are performed.

5.
Chin Clin Oncol ; 13(1): 5, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38453656

RESUMEN

BACKGROUND: The management of chemotherapy induced anemia (CIA) remains challenging. The potential risk and benefits in providing patient-centered care need to be balanced; the disease is multifactorial; and the major treatments including red blood cell (RBC) transfusions, erythropoiesis-stimulating agents (ESAs) and intravenous injection (i.v.)iron supplementation have a unique set of strengths and limitations. Also, most previous survey based on the patient data could not reveal the process of evaluation and decision-making for CIA treatment from a physician's perspective. As the comparison of China Society of Clinical Oncology (CSCO), National Comprehensive Cancer Network (NCCN) and European Society of Medical Oncology (ESMO) guidelines, the standard of CIA treatment in China will vary from United States and Europe, for example, the initial hemoglobin (Hb) for RBC transfusions. In order to understand the diagnosis, treatment, and unmet medical needs of CIA patients, the China Medical Education Association (CMEA), in conjunction with Cancer Hope Medium, initiated the first national survey of Chinese physicians regarding the diagnosis and treatment of CIA. METHODS: The CMEA sent an online, 12-item questionnaire (via wjx.cn) to physicians across China from September 1, 2022 to October 22, 2022. Two hundred and sixty-five samples were calculated usingsurveyplanet.com. The questionnaire evaluated the impact of anemia on chemotherapy interruption, initial treatment, the target Hb level of CIA in, and the current status of ESAs prescription in clinical practice. Respondents were asked to score their reasons for not using ESAs (including safety issues, drug access in practice or adherence) and the risk options of the current treatment including ESAs, RBC transfusion, and i.v.iron. RESULTS: A total of 331 questionnaires among 5,000 web visits were gathered, covering 247 hospitals in 29 provinces across China, of which 130 (53%) were tier IIIA hospitals, 50 (20%) were tier III B hospitals, 59 (24%) were tier IIA hospitals, and 8 (3%) were tier II B hospitals. The frequency of chemotherapy dose delay/reduction due to anemia was 24% [standard deviation (SD) 49%]. Most responding physicians rated an initial Hb level for ESAs treatment to be 80 g/L, with a favorable Hb level for chemotherapy being 100 g/L (60%), which would not limit treatment availability. The majority (67.6%, n=221) of physicians who responded indicated that they had used ESAs for anemia correction, while the others (32.4%, n=106) reported never using them. CONCLUSIONS: This is the first study in conducting a large-scale survey on the diagnosis and treatment of CIA in China from a physicians' perspective. We found that in China, nearly one-quarter of patients undergoing chemotherapy with concurrent anemia may experience interruption of chemotherapy and that the initiation of anemia treatment is not adequately timed. In treating CIA, most physicians prioritize the completion of chemotherapy via Hb level over treating the symptoms of anemia.


Asunto(s)
Anemia , Antineoplásicos , Hematínicos , Neoplasias , Médicos , Humanos , Estados Unidos , Antineoplásicos/uso terapéutico , Anemia/inducido químicamente , Anemia/tratamiento farmacológico , Hierro/efectos adversos , Hematínicos/efectos adversos , Neoplasias/tratamiento farmacológico , Neoplasias/complicaciones , Encuestas y Cuestionarios , Percepción
6.
Front Biosci (Landmark Ed) ; 28(11): 281, 2023 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-38062841

RESUMEN

BACKGROUND: Obesity is a significant health problem with an increasing incidence, causing a low-grade systemic inflammatory state and being implicated in various chronic diseases. Moreover, obesity has been shown to cause mitochondrial dysfunction through oxidative stress and inflammation, eventually affecting energy metabolism. However, high-intensity interval training (HIIT) can improve mitochondrial efficiency through exercise-induced mitochondrial adaptations. This systematic review and meta-analysis aims to examine the potential effects of HIIT on mitochondrial-associated indices in obese and overweight adults. METHODS: PubMed, Scopus, and Web of Science databases were searched. RESULTS: Twenty-eight eligible studies were included, involving 530 participants. HIIT was found to significantly improve the activity of citrate synthase (CS), cytochrome C (COX-IV), beta-hydroxyacyl CoA-dehydrogenase (ß-HAD), Complexes I-V as well as VO2max in overweight and obese individuals, whereas no significant changes were shown in PGC-1α and SIRT1. Interestingly, subgroup analyses revealed that CS, COX-IV, ß-HAD, and Complexes I-V activity exhibited a significant improvement only in the healthy subgroup. CONCLUSIONS: Overall, HIIT can be utilized to enhance mitochondrial-associated indices in overweight and obese individuals. However, this improvement may be health status dependent.


Asunto(s)
Entrenamiento de Intervalos de Alta Intensidad , Sobrepeso , Adulto , Humanos , Sobrepeso/metabolismo , Consumo de Oxígeno , Obesidad/metabolismo , Mitocondrias/metabolismo
7.
Artículo en Inglés, Ruso | MEDLINE | ID: mdl-38054222

RESUMEN

BACKGROUND: Management of patients in acute period of aneurysmal subarachnoid hemorrhage Hunt-Hess grade IV-V is still a complex and unsolved problem, especially regarding surgical treatment and various complications. OBJECTIVE: To analyze postoperative outcomes in patients undergoing surgery in acute period of aneurysmal subarachnoid hemorrhage Hunt-Hess grade IV-V between 2006 and 2020, as well as to assess various factors influencing treatment outcomes. MATERIAL AND METHODS: We analyzed 163 patients who underwent surgery within 21 days after aneurysmal subarachnoid hemorrhage Hunt-Hess grade IV-V. All patients were divided into 2 groups depending on the period: 2006-2011 (group 1) and 2012-2020 (group 2). RESULTS: Mortality reduced from 28.6% in group 1 to 8.3% in group 2. At the same time, incidence of vegetative state (GOS grade 2) increased from 4.8% to 17.4%. Incidence of outcomes GOS grade 3 - 5 was similar. CONCLUSION: Large or giant aneurysm, repeated preoperative subarachnoid hemorrhage, intraoperative aneurysm rupture and prolonged temporary clipping can impair postoperative outcomes in patients with hemorrhage Hunt-Hess grade IV-V. External ventricular drainage, intraarterial injection of verapamil, intracisternal administration of calcium channel blockers and active surgical tactics improve postoperative outcomes and reduce mortality.


Asunto(s)
Aneurisma Roto , Aneurisma Intracraneal , Hemorragia Subaracnoidea , Humanos , Aneurisma Intracraneal/cirugía , Hemorragia Subaracnoidea/cirugía , Estudios Retrospectivos , Resultado del Tratamiento , Aneurisma Roto/cirugía
8.
Heliyon ; 9(11): e21678, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38027855

RESUMEN

The Pseudomonas aeruginosa OG1 strain was used in the bacterial synthesis of MgSe compound nanoparticles. The obtained samples were subsequently shaped into nanocrystalline MgSe films, and their optical, structural, morphological, and electrical properties were assessed on glass and p-Si substrates. Structural and morphological characterizations showed that the fabricated thin film samples have a polycrystalline structure with high quality and uniform grain sizes. The MgSe films produced on glass substrates exhibit a direct spectral band gap of 2.53 eV, according to optical measurements. The Ag/MgSe/p-Si layered diode structure was fabricated using the produced MgSe nanoparticles and then characterized by electrical properties. Electrical measurements were carried out under these two conditions to assess the effects of dark and illumination conditions on the band dynamics of the heterostructure devices. Under illumination, the barrier height decreased while the interface density states distribution increased. These measurements showed that using bacterial-assisted grown MgSe nanocrystalline films, the developed Ag/MgSe/p-Si device structure exhibited a remarkable photoresponse and stable rectifying property. Green synthesis methods for the production of these nanocrystalline materials have the potential to offer low-cost alternatives for photosensitive applications.

9.
Nanomaterials (Basel) ; 13(21)2023 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-37947711

RESUMEN

We propose and demonstrate that temperature-dependent curve-fitting error values of the Schottky diode I-V curve in the forward regime can be an auxiliary diagnostic signal as the temperature-scan Capacitance DLTS (CDLTS) signals and helps to work time-efficiently with high accuracy when using the Laplace Transform (LT)-DLTS or Isothermal Capacitance transient spectroscopy (ICTS) method. Using Be-doped GaAs showing overlapping DLTS signals, we verify that the LT-DLTS or ICTS analysis within a specific temperature range around the characteristic temperature Tpeak coincides well with the results of the CDLTS and Fourier Transform DLTS performed within the whole temperature range. In particular, we found that the LT-DLTS signals appeared intensively around Tpeak, and we confirmed it with the ICTS result. The occurrence of the curve fitting error signal is attributed to the relatively increased misfit error by the increased thermal emission from the deep-level trap in the case near the Tpeak, because the applied transport model excludes defect characteristics.

10.
Membranes (Basel) ; 13(11)2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-37999371

RESUMEN

An electrochemical hydrogen pump (EHP) with a proton exchange membrane (PEM) used as part of fusion cycle systems successfully combines the processes of hydrogen extraction, purification and compression in a single device. This work comprises a novel study of the effect of ionizing radiation on the properties of the PEM as part of the EHP. Radiation exposure leads to nonspecific degradation of membranes, changes in their structure, and destruction of side and matrix chains. The findings from this work reveal that the replacement of sulfate groups in the membrane structure with carboxyl and hydrophilic groups leads to a decrease in conductivity from 0.115 to 0.103 S cm-1, which is reflected in halving the device performance at a temperature of 30 °C. The shift of the ionomer peak of small-angle X-ray scattering curves from 3.1 to 4.4 nm and the absence of changes in the water uptake suggested structural changes in the PEM after the irradiation. Increasing the EHP operating temperature minimized the effect of membrane irradiation on the pump performance, but enhanced membrane drying at low pressure and 50 °C, which caused a current density drop from 0.52 to 0.32 A·cm-2 at 0.5 V.

11.
Synth Biol (Oxf) ; 8(1): ysad014, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38022744

RESUMEN

Reproducibility has been identified as an outstanding challenge in science, and the field of synthetic biology is no exception. Meeting this challenge is critical to allow the transformative technological capabilities emerging from this field to reach their full potential to benefit the society. We discuss the current state of reproducibility in synthetic biology and how improvements can address some of the central shortcomings in the field. We argue that the successful adoption of reproducibility as a routine aspect of research and development requires commitment spanning researchers and relevant institutions via education, incentivization and investment in related infrastructure. The urgency of this topic pervades synthetic biology as it strives to advance fundamental insights and unlock new capabilities for safe, secure and scalable applications of biotechnology. Graphical Abstract.

12.
Cureus ; 15(9): e44543, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37789997

RESUMEN

Public health experts worldwide have emphasized cervical cancer since it is a substantial global health burden primarily affecting women. This article thoroughly reviews the public health approach to eradicating and managing cervical cancer. The public health community seeks to lower the prevalence, morbidity, and mortality linked to this preventable disease by integrating primary prevention by means of vaccination against the human papillomavirus (HPV), secondary prevention using screening and early identification, and tertiary prevention through improved therapy and supportive care. In order to accomplish broad vaccination coverage and ultimately effectively prevent cervical cancer, it remains crucial to address obstacles to vaccine accessibility, reluctance, and fair distribution. Early identification and subsequent treatments depend greatly on cervical cancer screening programs. This study explores several screening methods, such as Papanicolaou (Pap) tests based on cytology and cutting-edge technologies like molecular assays and HPV detection. The detection of precancerous lesions and early-stage malignancies, permitting prompt treatment, has shown significant promise when integrating these technologies into coordinated population-based screening programs. The study also underlines the significance of addressing cervical cancer burden inequities, particularly in resource-constrained areas where access to preventative and curative care is constrained. Innovative and affordable methods for addressing marginalized groups are studied, including community-based outreach programs, mobile health technology, and local healthcare practitioners and community leaders in awareness campaigns. The research also examines improvements in cervical cancer treatment procedures, such as surgery, radiation, chemotherapy, and immunotherapy. It improves therapeutic efficacy and patient survival rates by incorporating various modalities into a multidisciplinary strategy. Highlighted palliative care and psychological support are crucial for patients who have advanced cervical carcinoma.

13.
Materials (Basel) ; 16(18)2023 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-37763415

RESUMEN

Our investigation focused on assessing the influence of the metamorphic buffer in metamorphic high-electron-mobility transistors (MHEMT) that were grown on GaAs substrates. While an MHEMT exhibited elevated off-state current levels, its direct current (DC) and radio frequency (RF) traits were found to be comparable to those of InP-based lattice-matched high-electron-mobility transistors (LM-HEMTs). However, the Pulsed I-V measurement results confirmed the presence of the fast transient charging effect, leading to a more substantial degradation in drain current observed in MHEMT. In addition, through the low-frequency noise characteristics, it was confirmed that the dominant trapping location was located in the bulk site. The slope of the 1/f noise measurement indicated that the primary trapping site was in proximity to the bulk traps. The carrier-number-fluctuation (CNF) model was employed to extract the bulk trap density (Nt). For the LM-HEMTs, the value was at 3.27 × 1016 eV-1·cm-3, while for the MHEMT, it was 3.56 × 1017 eV-1·cm-3.

14.
Heliyon ; 9(9): e19387, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37662718

RESUMEN

Ethiopia is close to the equator and has enormous potential as a solar energy resource that has yet to be realized. The country has some small-scale diesel-based power generation, and all universities and government agencies have installed standby generator sets for supplying power when the grid is interrupted. Ethiopia is a developing nation with a significant reliance on oil imports and insufficient rural electrification, which exacerbates the problem of poverty. The increased cost of oil, frequent hard currency expenditures for oil, and exaggerated maintenance costs for the generators are the main reasons to undertake this feasibility study. As the assessments show, the annual average interruption was more than 800 h in the past five years in the Debre Markos University distribution feeder. A preliminary study on the techno-economic feasibility of the existing diesel generator set and PV system with the same rated power of 500 kW is conducted in this work. As the break-even point of the economic comparison shows, the existing diesel generator is not economically feasible as compared to the proposed PV-battery priority grid tie system due to high running and service costs. The study also shows the technical feasibility of solar energy, as the P-V and I-V characteristic curves illustrated on a single standard solar module indicate. As the economic comparison break-even point shows, the diesel-based generator set is not economical after 5 years due to the high operational and maintenance costs. As the results show, the proposed PV/Battery Priority system with a diesel generator for resilience is more environmentally friendly, reducing the carbon footprint by 94%.

15.
Front Chem ; 11: 1267199, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37720717

RESUMEN

Wide bandgap oxidized graphenes have garnered particular interest among the materials explored for these applications because of their exceptional semiconducting and optical properties. This study aims to investigate the tunability of the related properties in reduced graphene oxide (rGO) for potential use in energy conversion, storage, and optoelectronic devices. To accomplish this, we scrutinized crucial parameters of the synthesis process such as reduction time and temperature. Our findings demonstrate that controlling these parameters makes it possible to customize the optical bandgap of reduced graphene oxide within a range of roughly 2.2 eV-1.6 eV. Additionally, we observed that reduced graphene oxide has strong and superior absorption in the visible region, which is attributable to the existence of OFGs and defects. Notably, our results indicate that the absorption coefficients of reduced graphene oxide are up to almost three times higher (7426 ml mg-1 m-1) than those observed in dispersions of exfoliated graphene and graphene oxide (GO). To complement our findings, we employed several spectroscopic and morphological characterizations, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and electrical measurements. The implications of our results are significant for the development and design of future semiconductors for energy conversion and optoelectronic applications.

16.
J Neuroendovasc Ther ; 17(2): 47-55, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37502127

RESUMEN

Objective: To identify factors associated with the outcome and prognosis of coil embolization for poor-grade aneurysmal subarachnoid hemorrhage (aSAH). Methods: We retrospectively reviewed 118 patients with World Federation of Neurosurgical Societies (WFNS) grade IV or V subarachnoid hemorrhage at our institute between January 2010 and December 2020. Outcomes were assessed using modified Rankin Scale (mRS) scores at discharge and at six months after aSAH onset. In addition, patient background, aneurysm characteristics, and treatment outcome were compared between patients showing favorable (mRS scores: 0-2) and unfavorable (mRS scores: 3-6) outcomes at six months. Factors for change of mRS during follow-up were explored, and cut off values were calculated for age using the receiver operating characteristic analysis. Results: Endovascular treatment was performed in 51 of the 118 enrolled patients. Data were analyzed for 43 of these patients who underwent coil embolization of ruptured aneurysms and had complete datasets. The mean age was 61.7 years and 24 (55.8%) patients had WFNS grade V aSAH. Coil embolization-related complications were observed in three patients. There were no treatment-related deaths; however, eight patients (18.6%) died at three months. Multivariate analysis showed that the maximum diameter of the aneurysm (p=0.041) and the postoperative dual antiplatelet therapy (DAPT) (p=0.040) were associated with unfavorable and favorable outcomes, respectively. Older age (p=0.033) was independently associated with mRS score deterioration following discharge. Age 72 years and older was the cut off value for mRS deterioration. Conclusion: Aneurysm size and postoperative DAPT might be associated with outcomes at 6 months. Moreover, we identified older age as an independent factor that influences mRS deterioration following discharge; thus, especially in cases of elderly patients over 72 years of age, it is highly likely that long-term care to prevent disuse and regular follow-up on imaging will be necessary.

17.
Materials (Basel) ; 16(12)2023 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-37374651

RESUMEN

In this study, we present a detailed analysis of trapping characteristics at the AlxGa1-xN/GaN interface of AlxGa1-xN/GaN high-electron-mobility transistors (HEMTs) with reliability assessments, demonstrating how the composition of the Al in the AlxGa1-xN barrier impacts the performance of the device. Reliability instability assessment in two different AlxGa1-xN/GaN HEMTs [x = 0.25, 0.45] using a single-pulse ID-VD characterization technique revealed higher drain-current degradation (∆ID) with pulse time for Al0.45Ga0.55N/GaN devices which correlates to the fast-transient charge-trapping in the defect sites near the interface of AlxGa1-xN/GaN. Constant voltage stress (CVS) measurement was used to analyze the charge-trapping phenomena of the channel carriers for long-term reliability testing. Al0.45Ga0.55N/GaN devices exhibited higher-threshold voltage shifting (∆VT) caused by stress electric fields, verifying the interfacial deterioration phenomenon. Defect sites near the interface of the AlGaN barrier responded to the stress electric fields and captured channel electrons-resulting in these charging effects that could be partially reversed using recovery voltages. The quantitative extraction of volume trap density (Nt) using 1/f low-frequency noise characterizations unveiled a 40% reduced Nt for the Al0.25Ga0.75N/GaN device, further verifying the higher trapping phenomena in the Al0.45Ga0.55N barrier caused by the rougher Al0.45Ga0.55N/GaN interface.

18.
Micromachines (Basel) ; 14(6)2023 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-37374820

RESUMEN

Molybdenum disulfide (MoS2) has distinctive electronic and mechanical properties which make it a highly prospective material for use as a channel in upcoming nanoelectronic devices. An analytical modeling framework was used to investigate the I-V characteristics of field-effect transistors based on MoS2. The study begins by developing a ballistic current equation using a circuit model with two contacts. The transmission probability, which considers both the acoustic and optical mean free path, is then derived. Next, the effect of phonon scattering on the device was examined by including transmission probabilities into the ballistic current equation. According to the findings, the presence of phonon scattering caused a decrease of 43.7% in the ballistic current of the device at room temperature when L = 10 nm. The influence of phonon scattering became more prominent as the temperature increased. In addition, this study also considers the impact of strain on the device. It is reported that applying compressive strain could increase the phonon scattering current by 13.3% at L = 10 nm at room temperature, as evaluated in terms of the electrons' effective masses. However, the phonon scattering current decreased by 13.3% under the same condition due to the existence of tensile strain. Moreover, incorporating a high-k dielectric to mitigate the impact of scattering resulted in an even greater improvement in device performance. Specifically, at L = 6 nm, the ballistic current was surpassed by 58.4%. Furthermore, the study achieved SS = 68.2 mV/dec using Al2O3 and an on-off ratio of 7.75 × 104 using HfO2. Finally, the analytical results were validated with previous works, showing comparable agreement with the existing literature.

19.
Cureus ; 15(6): e40087, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37292107

RESUMEN

Intravenous ketamine infusions in subanesthetic doses have been shown to rapidly alleviate depressive symptoms. However, the efficacy of ketamine as an anesthetic during electroconvulsive therapy (ECT) for major depression has not yet been answered by a large randomized control trial (RCT). This scoping review aims to examine the available literature to determine whether the dose of ketamine used during ECT influences the response to treatment. A literature search was conducted on PubMed to identify all published RCTs within the last 10 years which compared ketamine anesthesia during ECT for major depression with another anesthetic. Studies using low (<0.8 mg/kg) versus high (≥0.8 mg/kg) doses of ketamine during ECT were evaluated for the differences in outcomes using depression rating scales. Studies that examined ketamine as a standalone treatment for depression or focused primarily on the anesthetic benefits of ketamine were excluded from our review. Fifteen studies were utilized for this literature review. Overall, the studies showed inconsistent results in terms of the speed and magnitude of response to ketamine-assisted ECT in patients with major depression. Limitations of the available literature are discussed, including the lack of head-to-head comparisons, differences in methodology, inclusion/exclusion criteria, and primary and secondary endpoints.

20.
Molecules ; 28(9)2023 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-37175193

RESUMEN

Silicon-air batteries (SABs) are attracting considerable attention owing to their high theoretical energy density and superior security. In this study, In and Ga were doped into Si electrodes to optimize the capability of Si-air batteries. Varieties of Si-In/SiO2 and Si-Ga/SiO2 atomic interfaces were built, and their properties were analyzed using density functional theory (DFT). The adsorption energies of the SiO2 passivation layer on In- and Ga-doped silicon electrodes were higher than those on pure Si electrodes. Mulliken population analysis revealed a change in the average number of charge transfers of oxygen atoms at the interface. Furthermore, the local device density of states (LDDOS) of the modified electrodes showed high strength in the interfacial region. Additionally, In and Ga as dopants introduced new energy levels in the Si/SiO2 interface according to the projected local density of states (PLDOS), thus reducing the band gap of the SiO2. Moreover, the I-V curves revealed that doping In and Ga into Si electrodes enhanced the current flow of interface devices. These findings provide a mechanistic explanation for improving the practical efficiency of silicon-air batteries through anode doping and provide insight into the design of Si-based anodes in air batteries.

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