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1.
Sci Rep ; 11(1): 20118, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34635765

RESUMO

We investigate the magnetic properties in carbonyl iron (CI) particles before and after Ni[Formula: see text] and H[Formula: see text] ion beam irradiation. Upon increasing temperatures, the saturation magnetization ([Formula: see text]) in hysteresis loops exhibits an anomalous increase at a high temperature for the unirradiated and the Ni[Formula: see text]-beam-irradiated samples, unlike in H[Formula: see text]-beam-irradiated sample. Moreover, the magnetization values at low and high temperatures are more intense after Ni[Formula: see text] beam irradiation, whereas after H[Formula: see text] beam irradiation those are remarkably suppressed. Hematite ([Formula: see text]-Fe[Formula: see text]O[Formula: see text]) phase introduced on the surface of our CI particles undergoes the Morin transition that was observed in our magnetization-temperature curves. The Morin transition causing canted antiferromagnetism above the Morin temperature was found in the unirradiated and Ni[Formula: see text]-beam-irradiated samples, but not in H[Formula: see text]-beam-irradiated sample. It is thus revealed that the CI particles undergoing the Morin transition cause the anomalous increase in [Formula: see text]. We may suggest that Ni[Formula: see text] ion beam increases uncompensated surface spins on the CI particles resulting in a more steep Morin transition and the intensified [Formula: see text]. Ion-beam irradiation may thus be a good tool for controlling the magnetic properties of CI particles, tailoring our work for future applications.

2.
Micromachines (Basel) ; 12(8)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34442485

RESUMO

This study investigated the combined effects of proton irradiation and surface pre-treatment on the current characteristics of Gallium Nitride (GaN)-based metal-insulator-semiconductor high-electron-mobility-transistors (MIS-HEMTs) to evaluate the radiation hardness involved with the Silicon Nitride (SiN) passivation/GaN cap interface. The impact of proton irradiation on the static and dynamic current characteristics of devices with and without pre-treatment were analyzed with 5 MeV proton irradiation. In terms of transfer characteristics before and after the proton irradiation, the drain current of the devices without and with pre-treatment were reduced by an increase in sheet and contact resistances after the proton irradiation. In contrast with the static current characteristics, the gate-lag characteristics of the device with pre-treatment were significantly degenerated. In the device with pre-treatment, the hydrogen passivation for surface states of the GaN cap was formed by the pre-treatment and SiN deposition processes. Since the hydrogen passivation was removed by the proton irradiation, the newly created vacancies resulted in the degeneration of gate-lag characteristics. After nine months in an ambient atmosphere, the gate-lag characteristics of the device with pre-treatment were recovered because of the hydrogen recombination. These results demonstrated that the radiation hardness of MIS-HEMTs was affected by the SiN/GaN interface quality.

3.
Int J Mol Sci ; 22(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361041

RESUMO

Traumatic brain injury (TBI) is a leading cause of disability and mortality worldwide. It can instigate immediate cell death, followed by a time-dependent secondary injury that results from disproportionate microglial and astrocyte activation, excessive inflammation and oxidative stress in brain tissue, culminating in both short- and long-term cognitive dysfunction and behavioral deficits. Within the brain, the hippocampus is particularly vulnerable to a TBI. We studied a new pomalidomide (Pom) analog, namely, 3,6'-dithioPom (DP), and Pom as immunomodulatory imide drugs (IMiD) for mitigating TBI-induced hippocampal neurodegeneration, microgliosis, astrogliosis and behavioral impairments in a controlled cortical impact (CCI) model of TBI in rats. Both agents were administered as a single intravenous dose (0.5 mg/kg) at 5 h post injury so that the efficacies could be compared. Pom and DP significantly reduced the contusion volume evaluated at 24 h and 7 days post injury. Both agents ameliorated short-term memory deficits and anxiety behavior at 7 days after a TBI. The number of degenerating neurons in the CA1 and dentate gyrus (DG) regions of the hippocampus after a TBI was reduced by Pom and DP. DP, but not Pom, significantly attenuated the TBI-induced microgliosis and DP was more efficacious than Pom at attenuating the TBI-induced astrogliosis in CA1 and DG at 7D after a TBI. In summary, a single intravenous injection of Pom or DP, given 5 h post TBI, significantly reduced hippocampal neurodegeneration and prevented cognitive deficits with a concomitant attenuation of the neuroinflammation in the hippocampus.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Gliose/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Fatores Imunológicos/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Talidomida/análogos & derivados , Animais , Lesões Encefálicas Traumáticas/complicações , Cognição , Gliose/etiologia , Hipocampo/metabolismo , Fatores Imunológicos/farmacologia , Masculino , Memória , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Sprague-Dawley , Talidomida/farmacologia , Talidomida/uso terapêutico
4.
Korean J Physiol Pharmacol ; 25(5): 439-448, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34448461

RESUMO

DA-9601 is an extract obtained from Artemisia asiatica, which has been reported to have anti-inflammatory effects on gastrointestinal lesions; however, its possible anti-inflammatory effects on the small intestine have not been studied yet. Therefore, in this study, we investigated the protective effects of DA-9601 against the ACF-induced small intestinal inflammation. Inflammation of the small intestine was confirmed by histological studies and the changes in the CD4+ T cell fraction induced by the inflammation-related cytokines, and the inflammatory reactions were analyzed. Multifocal discrete small necrotic ulcers with intervening normal mucosa were frequently observed after treatment with ACF. The expression of IL-6 , IL-17, and TNF-α genes was increased in the ACF group; however, it was found to have been significantly decreased in the DA-9601 treated group. In addition, DA-9601 significantly decreased the levels of proinflammatory mediators such as IL-1ß, GMCSF, IFN-γ, and TNF-α; the anti-inflammatory cytokine IL-10, on the other hand, was observed to have increased. It is known that inflammatory mediators related to T cell imbalance and dysfunction continuously activate the inflammatory response, causing chronic tissue damage. The fractions of IFN-γ+ Th1 cells, IL-4+ Th2 cells, IL-9+ Th9 cells, IL-17+ Th17 cells, and Foxp3+ Treg cells were significantly decreased upon DA-9601 treatment. These data suggest that the inflammatory response induced by ACF is reduced by DA-9601 via lowering of the expression of genes encoding the inflammatory cytokines and the concentration of inflammatory mediators. Furthermore, DA-9601 inhibited the acute inflammatory response mediated by T cells, resulting in an improvement in ACF-induced enteritis.

5.
J Tradit Chin Med ; 41(3): 355-359, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34114391

RESUMO

OBJECTIVE: To investigate the efficacy of horse oil on lipopolysaccharide (LPS)-induced inflammation in human keratinocytes. METHODS: Western blot analysis was performed to measure the expression of cyclooxygenase-2 (COX-2) and IκBα. ELISA was used to analyze prostaglandin E2 (PGE2) levels. RESULTS: Horse oil decreased LPS-induced COX-2 and PGE2 levels in a dose-dependent manner. Nuclear factor-kappa B (NF-κB) plays a key role in the expression of inflammatory cytokines and mediators. Therefore, we investigated the influence of horse oil on the NF-κB signaling pathways. Horse oil inhibited translocation of NF-κB from the cytosol to the nucleus. Furthermore, LPS-induced degradation of IκBα was recovered by horse oil. The activation of p38 mitogen-activated protein kinase (MAPK) reportedly induces degradation of IκBα In agreement with this, LPS activated p38 MAPK and caused IκBα degradation. Conversely, horse oil inhibited LPS-induced p38 MAPK activation and IκBα degradation. In addition, a specific p38 MAPK inhibitor, SB203580, blocked IκBα degradation. CONCLUSION: Horse oil decreased COX-2 and PGE2 by inhibiting p38 MAPK activation, IκBα degradation, and the translocation of NF-κB.

6.
Ann Neurol ; 90(2): 285-299, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34180075

RESUMO

OBJECTIVE: Low-level somatic mosaicism in the brain has been shown to be a major genetic cause of intractable focal epilepsy. However, how a relatively few mutation-carrying neurons are able to induce epileptogenesis at the local network level remains poorly understood. METHODS: To probe the origin of epileptogenesis, we measured the excitability of neurons with MTOR mutation and nearby nonmutated neurons recorded by whole-cell patch-clamp and array-based electrodes comparing the topographic distribution of mutation. Computational simulation is used to understand neural network-level changes based on electrophysiological properties. To examine the underlying mechanism, we measured inhibitory and excitatory synaptic inputs in mutated neurons and nearby neurons by electrophysiological and histological methods using the mouse model and postoperative human brain tissue for cortical dysplasia. To explain non-cell-autonomous hyperexcitability, an inhibitor of adenosine kinase was injected into mice to enhance adenosine signaling and to mitigate hyperactivity of nearby nonmutated neurons. RESULTS: We generated mice with a low-level somatic mutation in MTOR presenting spontaneous seizures. The seizure-triggering hyperexcitability originated from nonmutated neurons near mutation-carrying neurons, which proved to be less excitable than nonmutated neurons. Interestingly, the net balance between excitatory and inhibitory synaptic inputs onto mutated neurons remained unchanged. Additionally, we found that inhibition of adenosine kinase, which affects adenosine metabolism and neuronal excitability, reduced the hyperexcitability of nonmutated neurons. INTERPRETATION: This study shows that neurons carrying somatic mutations in MTOR lead to focal epileptogenesis via non-cell-autonomous hyperexcitability of nearby nonmutated neurons. ANN NEUROL 2021;90:285-299.

7.
Nanomicro Lett ; 13(1): 87, 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-34138339

RESUMO

HIGHLIGHTS: Ultrathin and defect-free graphene ink is prepared through a high-throughput fluid dynamics process, resulting in a high exfoliation yield (53.5%) and a high concentration (47.5 mg mL-1). A screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m-1 and good mechanical flexibility. An electrochemical sodium ion sensor based on graphene ink exhibits an excellent potentiometric sensing performance in a mechanically bent state. Real-time monitoring of sodium ion concentration in sweat is demonstrated. Conductive inks based on graphene materials have received significant attention for the fabrication of a wide range of printed and flexible devices. However, the application of graphene fillers is limited by their restricted mass production and the low concentration of their suspensions. In this study, a highly concentrated and conductive ink based on defect-free graphene was developed by a scalable fluid dynamics process. A high shear exfoliation and mixing process enabled the production of graphene at a high concentration of 47.5 mg mL-1 for graphene ink. The screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m-1 and maintains high conductivity under mechanical bending, compressing, and fatigue tests. Based on the as-prepared graphene ink, a printed electrochemical sodium ion (Na+) sensor that shows high potentiometric sensing performance was fabricated. Further, by integrating a wireless electronic module, a prototype Na+-sensing watch is demonstrated for the real-time monitoring of the sodium ion concentration in human sweat during the indoor exercise of a volunteer. The scalable and efficient procedure for the preparation of graphene ink presented in this work is very promising for the low-cost, reproducible, and large-scale printing of flexible and wearable electronic devices.

8.
Childs Nerv Syst ; 37(7): 2239-2244, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33939017

RESUMO

OBJECTIVE: Seizures are one of the most common emergencies in the neonatal intensive care unit (NICU). They are identified through visual inspection of electroencephalography (EEG) reports and treated by neurophysiologic experts. To support clinical seizure detection, several feature-based automatic neonatal seizure detection algorithms have been proposed. However, as they were unsuitable for clinical application due to their low accuracy, we developed a new seizure detection algorithm using machine learning for single-channel EEG to overcome these limitations. METHODS: The dataset applied in our algorithm contains EEG recordings from human neonates. A 19-channel EEG system recorded the brain waves of 79 term neonates admitted to the NICU at the Helsinki University Hospital. From these datasets, we selected six patients with conformational seizure annotations for the pilot study and allocated four and two patients for our training and testing datasets, respectively. The presence of seizures in the EEGs was annotated independently by three experts through visual interpretation. We divided the data into epochs of 5 s each and further defined a seizure block to label the annotations from each expert recorded every second. Subsequently, to create a balanced dataset, any data point with a non-seizure label was moved to the training and test dataset. RESULT: The developed principal component feature-extracted machine learning algorithm used 62.5% of the relative time (only 5 s for decision) of the baseline, reaching an area under the ROC curve score of 0.91. The effect of diversified parameters was meticulously examined, and 100 principal components were extracted to optimize the model performance. CONCLUSION: Our machine learning-based seizure detection algorithm exhibited the potential for clinical application in NICUs, general wards, and at home and proved its convenience by requiring only a single channel for implementation.


Assuntos
Eletroencefalografia , Convulsões , Algoritmos , Humanos , Recém-Nascido , Aprendizado de Máquina , Projetos Piloto , Convulsões/diagnóstico
9.
Retina ; 41(9): 1791-1798, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33840794

RESUMO

PURPOSE: Although moyamoya disease primarily affects the carotid artery in the ophthalmic artery bifurcation area, retinal vascular abnormalities in moyamoya disease have rarely been reported. The purpose of this report is to describe clinical findings of patients with retinal vascular occlusion in patients with moyamoya disease and present its clinical significance. METHODS: We reviewed and analyzed patients with moyamoya disease with retinal vascular occlusions. For this, a retrospective medical chart review was performed in a tertiary medical center and a literature search was performed using PubMed and EMBASE until September 2020. RESULTS: Patients with retinal artery occlusion (RAO) were significantly younger than patients with retinal vein occlusion (25.0 vs. 40.1 years, P = 0.023). Of 14 patients, retinal vascular occlusion was the presenting sign of moyamoya disease in 8 (57.1%) patients. The occlusion site at the carotid artery was proximal to the ophthalmic artery bifurcation area in 8 (57.1%) patients. Legal blindness occurred in 8 (57.1%) patients at final visits. CONCLUSION: Retinal vascular occlusion is a rare but sight-threatening ocular complication in patients with moyamoya disease. Overall, younger age may be a risk factor for RAO, whereas older age for retinal vein occlusion. Retinal vascular occlusion can be an important indicator of moyamoya disease screening, especially in relatively younger and healthy patients.

10.
Front Neurosci ; 15: 656921, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33854417

RESUMO

Neuroinflammation represents a common trait in the pathology and progression of the major psychiatric and neurodegenerative disorders. Neuropsychiatric disorders have emerged as a global crisis, affecting 1 in 4 people, while neurological disorders are the second leading cause of death in the elderly population worldwide (WHO, 2001; GBD 2016 Neurology Collaborators, 2019). However, there remains an immense deficit in availability of effective drug treatments for most neurological disorders. In fact, for disorders such as depression, placebos and behavioral therapies have equal effectiveness as antidepressants. For neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, drugs that can prevent, slow, or cure the disease have yet to be found. Several non-traditional avenues of drug target identification have emerged with ongoing neurological disease research to meet the need for novel and efficacious treatments. Of these novel avenues is that of neuroinflammation, which has been found to be involved in the progression and pathology of many of the leading neurological disorders. Neuroinflammation is characterized by glial inflammatory factors in certain stages of neurological disorders. Although the meta-analyses have provided evidence of genetic/proteomic upregulation of inflammatory factors in certain stages of neurological disorders. Although the mechanisms underpinning the connections between neuroinflammation and neurological disorders are unclear, and meta-analysis results have shown high sensitivity to factors such as disorder severity and sample type, there is significant evidence of neuroinflammation associations across neurological disorders. In this review, we summarize the role of neuroinflammation in psychiatric disorders such as major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, and bipolar disorder, as well as in neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, and introduce current research on the potential of immunomodulatory imide drugs (IMiDs) as a new treatment strategy for these disorders.

11.
ACS Pharmacol Transl Sci ; 4(2): 980-1000, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33860215

RESUMO

Neuroinflammation contributes to delayed secondary cell death following traumatic brain injury (TBI), has the potential to chronically exacerbate the initial insult, and represents a therapeutic target that has largely failed to translate into human efficacy. Thalidomide-like drugs have effectively mitigated neuroinflammation across cellular and animal models of TBI and neurodegeneration but are complicated by adverse actions in humans. We hence developed N-adamantyl phthalimidine (NAP) as a new thalidomide-like drug to mitigate inflammation without binding to cereblon, a key target associated with the antiproliferative, antiangiogenic, and teratogenic actions seen in this drug class. We utilized a phenotypic drug discovery approach that employed multiple cellular and animal models and ultimately examined immunohistochemical, biochemical, and behavioral measures following controlled cortical impact (CCI) TBI in mice. NAP mitigated LPS-induced inflammation across cellular and rodent models and reduced oligomeric α-synuclein and amyloid-ß mediated inflammation. Following CCI TBI, NAP mitigated neuronal and synaptic loss, neuroinflammation, and behavioral deficits, and is unencumbered by cereblon binding, a key protein underpinning the teratogenic and adverse actions of thalidomide-like drugs in humans. In summary, NAP represents a new class of thalidomide-like drugs with anti-inflammatory actions for promising efficacy in the treatment of TBI and potentially longer-term neurodegenerative disorders.

12.
Artigo em Inglês | MEDLINE | ID: mdl-33921478

RESUMO

Clinical practitioners treating moyamoya disease recognize the need for a systematic approach to better manage the disease in adolescent patients with the disease. Methods: This study aimed to develop and evaluate the validity and reliability of a disease scale which measures the health-related behaviors of adolescents with moyamoya disease. Results: The final 12-item Moyamoya-HB Scale for adolescents was categorized by three sub-domains: implementation of treatment for moyamoya disease (four items); health promoting behavior for moyamoya disease (four items); and health coping behavior for moyamoya disease (four items). Overall, these factors explained 68.97% of the total variance. The results of the confirmative factor analysis supported the construct, convergent and discriminant validity of the three sub-domains. The Moyamoya-HB Scale for adolescents also demonstrated a concurrent validity with the Korean Adolescents' Health Behaviors Tool (r = 0.59, p < 0.001). Reliability analysis showed an acceptable-to-high Cronbach's alpha of 0.865 in total, and the subscales ranged from 0.800 to 0.841. Conclusions: Initial findings support the Moyamoya-HB Scale as a reliable and valid measure of health behaviors in adolescents with moyamoya disease.


Assuntos
Comportamento do Adolescente , Doença de Moyamoya , Adolescente , Análise Fatorial , Comportamentos Relacionados com a Saúde , Humanos , Doença de Moyamoya/diagnóstico , Psicometria , Reprodutibilidade dos Testes , Inquéritos e Questionários
13.
Ann Neurol ; 89(6): 1248-1252, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33834539

RESUMO

Brain mosaic mutations are a major cause of refractory focal epilepsies with cortical malformations such as focal cortical dysplasia, hemimegalencephaly, malformation of cortical development with oligodendroglial hyperplasia in epilepsy, and ganglioglioma. Here, we collected cerebrospinal fluid (CSF) during epilepsy surgery to search for somatic variants in cell-free DNA (cfDNA) using targeted droplet digital polymerase chain reaction. In 3 of 12 epileptic patients with known somatic mutations previously identified in brain tissue, we here provide evidence that brain mosaicism can be detected in the CSF-derived cfDNA. These findings suggest future opportunities for detecting the mutant allele driving epilepsy in CSF. ANN NEUROL 2021;89:1248-1252.


Assuntos
Encéfalo , Ácidos Nucleicos Livres/líquido cefalorraquidiano , Epilepsia Resistente a Medicamentos/genética , Adolescente , Criança , Pré-Escolar , Epilepsia Resistente a Medicamentos/líquido cefalorraquidiano , Feminino , Humanos , Lactente , Masculino , Mutação
14.
Childs Nerv Syst ; 37(7): 2233-2238, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33755793

RESUMO

OBJECTIVE: To investigate the feasibility and clinical effectiveness of performing multiple burr hole surgery in pediatric moyamoya patients as a response to failed modified encephaloduroarteriosynangiosis (mEDAS). METHODS: From January 2014 to May 2018, multiple burr hole surgery (MBS) was conducted on 16 hemispheres in 12 patients as a secondary treatment following mEDAS. The male-to-female ratio was 1:2 and the average age at the time of mEDAS was 6 years old. The average patient age was 9 ± 3 years olds (range 7-17) at the time of MBS which occurred an average of 46 months after mEDAS. An average of 10 ± 1 holes (range 8-13) were made. Time-to-peak (TTP) magnetic resonance images (MRI) were taken along 20 axial cuts. Of these cuts, two consecutive cuts on the lateral ventricle were selected to calculate the average value of the region of interest (ROI). The value of the cerebellum was subtracted from the average value of two consecutive cuts. The ROI value was analyzed using a paired t test by SPSS 20 (SPSS Inc., Chicago, IL, USA). RESULTS: All 16 cases presented improvement of clinical symptoms as determined by ROI analysis of the TTP MRI images. The average ROI value was 5.03 ± 6.36 before MBS and - 15.54 ± 9.42 after MBS. The average change in the ROI value was - 20.58 ± 12.59. The ROI value decreased in all cases after MBS. Magnetic resonance angiography (MRA) also showed a positive effect on vascularization. CONCLUSION: In pediatric moyamoya patients, MBS is recommended as secondary option as a response to failed mEDAS. Its clinical effectiveness was shown by analyzing TTP images and assisted by MRA and digital subtraction angiography.


Assuntos
Revascularização Cerebral , Doença de Moyamoya , Angiografia Digital , Criança , Estudos de Viabilidade , Feminino , Humanos , Lactente , Masculino , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Trepanação
15.
Cancer Res Treat ; 53(2): 378-388, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33138347

RESUMO

PURPOSE: Atypical teratoid/rhabdoid tumor (ATRT) is a highly aggressive malignancy with peak incidence in children aged less than 3 years. Standard treatment for central nervous system ATRT in children under the age of 3 years have not been established yet. The objective of this study was to analyze characteristics and clinical outcomes of ATRT in children aged less than 3 years. Materials and Methods: A search of medical records from seven centers was performed between January 2005 and December 2016. RESULTS: Forty-three patients were enrolled. With a median follow-up of 90 months, 27 patients (64.3%) showed at least one episode of disease progression (PD). The first date of PD was at 160 days after diagnosis. The 1- and 3-year progression-free survivals (PFS) were 51.2% and 28.5%, respectively. The 1- and 3-year overall survivals were 61.9% and 38.1%, respectively. The 3-year PFS was improved from 0% in pre-2011 to 47.4% in post-2011. Excluding one patient who did not receive any further therapy after surgery, 27 patients died due to PD (n=21), treatment-related toxicity (n=5), or unknown cause (n=1). In univariate analysis, factors associated with higher 3-year PFS were no metastases, diagnosis after 2011, early adjuvant radiotherapy, and high-dose chemotherapy (HDCT). In multivariate analysis, the use of HDCT and adjuvant radiotherapy remained significant prognostic factors for PFS (both p < 0.01). CONCLUSION: Aggressive therapy including early adjuvant radiotherapy and HDCT could be considered to improve outcomes of ATRT in children under the age of 3 years.

16.
Micromachines (Basel) ; 11(12)2020 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-33322847

RESUMO

In this work, Gallium Nitride (GaN)-based p-i-n diodes were designed using a computer aided design (TCAD) simulator for realizing a betavoltaic (BV) cell with a high output power density (Pout). The short-circuit current density (JSC) and open-circuit voltage (VOC) of the 17 keV electron-beam (e-beam)-irradiated diode were evaluated with the variations of design parameters, such as the height and doping concentration of the intrinsic GaN region (Hi-GaN and Di-GaN), which influenced the depletion width in the i-GaN region. A high Hi-GaN and a low Di-GaN improved the Pout because of the enhancement of absorption and conversion efficiency. The device with the Hi-GaN of 700 nm and Di-GaN of 1 × 1016 cm-3 exhibited the highest Pout. In addition, the effects of native defects in the GaN material on the performances were investigated. While the reverse current characteristics were mainly unaffected by donor-like trap states like N vacancies, the Ga vacancies-induced acceptor-like traps significantly decreased the JSC and VOC due to an increase in recombination rate. As a result, the device with a high acceptor-like trap density dramatically degenerated the Pout. Therefore, growth of the high quality i-GaN with low acceptor-like traps is important for an enhanced Pout in BV cell.

17.
Nanomaterials (Basel) ; 10(11)2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33143313

RESUMO

The device performance deterioration mechanism caused by the total ionizing dose effect after the γ-ray irradiation was investigated in GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) for a 5 nm-thick SiN and HfO2 gate dielectric layer. The γ-ray radiation hardness according to the gate dielectric layer was also compared between the two different GaN-based MIS-HEMTs. Although HfO2 has exhibited strong tolerance to the total ionizing dose effect in Si-based devices, there is no detail report of the γ-ray radiation effects in GaN-based MIS-HEMTs employing a HfO2 gate dielectric layer. The pulsed-mode stress measurement results and carrier mobility behavior revealed that the device properties not only have direct current (DC) characteristics, but radio frequency (RF) performance has also been mostly degraded by the deterioration of the gate dielectric quality and the trapped charges inside the gate insulator. We also figured out that the immunity to the γ-ray radiation was improved when HfO2 was employed instead of SiN as a gate dielectric layer due to its stronger endurance to the γ-ray irradiation. Our results highlight that the application of a gate insulator that shows superior immunity to the γ-ray irradiation is a crucial factor for the improvement of the total ionizing dose effect in GaN-based MIS-HEMTs.

18.
J Clin Neurol ; 16(4): 624-632, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33029969

RESUMO

BACKGROUND AND PURPOSE: Moyamoya disease (MMD) is a rare form of intracranial stenoocclusive disease that can be associated with intracranial aneurysms. We evaluated the clinical features and outcomes of MMD-associated aneurysms while focusing on their locations. METHODS: Between January 1998 and December 2018 there were 1,302 adult and pediatric patients diagnosed as MMD at a single institution. These patients included 38 with 44 MMD-associated aneurysms. The MMD-associated aneurysms were classified into two groups based on their locations: major-artery aneurysms and non-major-artery aneurysms. The clinical and radiological data for patients with MMD-associated aneurysms were reviewed retrospectively. RESULTS: The 44 MMD-associated aneurysms comprised 28 in major arteries and 16 in nonmajor arteries. All of the major-artery aneurysms were initially unruptured lesions, and follow-up angiography showed that 23 (82.1%) had an improved or stable status and 5 (17.9%) had a worse status. The non-major-artery aneurysms comprised 10 ruptured and 6 unruptured lesions, and follow-up angiography showed that 11 (68.8%) had improved or were stable and 5 (31.2%) had worsened. At the latest follow-up, there were four cases of unfavorable outcome: two initial hemorrhagic insults, one treatment-related morbidity, and one repeated-hemorrhage case. CONCLUSIONS: MMD-associated aneurysms occurred in 3.3% of the MMD cohort in this study, of which 63.6% were major-artery aneurysms and 36.4% were non-major-artery aneurysms. The major-artery group included 17.9% that became angiographically worse, while 31.2% were growing or hemorrhaging in the non-major-artery group.

19.
Ultrasonography ; 39(4): 367-375, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32962332

RESUMO

PURPOSE: The purpose of this study was to identify the optimal timing for screening spinal cord ultrasonography (US) to detect filum terminale lipoma in infants. METHODS: We retrospectively reviewed infants (<12 months old) who underwent repeated spinal cord US between April 2011 and January 2019. We excluded infants if they only had one US examination, or if they had lesions other than filum terminale lipoma. Infants with filum terminale lipoma on magnetic resonance imaging were included in the lipoma group and the others in the control group. A linear mixed model was used to assess differences in the growth pattern of filum terminale thickness by age and group. The cutoff thickness on US and its diagnostic performance were assessed according to age. RESULTS: Among 442 infants with 901 US examinations, 46 were included in the lipoma group and 58 in the control group. Sixty-seven infants had unmeasurable filum terminale thickness on initial US, including 55 neonates (82.1%) before 1 month of age. The lipoma group had significantly greater filum terminale thickness than the control group (P<0.001). Thickness increased with age in the lipoma group (P=0.027). The sensitivity of US was 87.5% and the area under the receiver operating characteristic curve was 0.949 (95% confidence interval, 0.849 to 0.991) with a cutoff value of 1.1 mm in 4- to 6-month-old infants. CONCLUSION: Screening spinal cord US could effectively diagnose filum terminale lipoma in 4- to 6-month-old infants with a cutoff thickness of 1.1 mm. Spinal cord US can be used to screen young infants with intraspinal abnormalities.

20.
Pharmaceutics ; 12(8)2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32785038

RESUMO

This study aimed to restore the skin barrier function from atopic dermatitis (AD) via treatment with leucine-rich glioma inactivated 3 (LGI3) peptide. Male NC/Nga mice (7 weeks, 20 g) were randomly allocated into three groups (control, AD, and LGI3 group). After induction of AD skin lesions with Dermatophagoides farinae ointment, mice were treated with LGI3. The clinical score of AD was the highest and the dorsal skin thickness was the thickest in the AD group. In contrast, LGI3 treatment improved the clinical score and the dorsal skin thickness compared to the AD model. LGI3 treatment suppressed histopathological thickness of the epithelial cell layer of the dorsal skin. LGI3 treatment could indirectly reduce mast cell infiltration through restoring the barrier function of the skin. Additionally, the filaggrin expression was increased in immunohistochemical evaluation. In conclusion, the ameliorating effect and maintaining skin barrier homeostasis in the AD murine model treated with LGI3 could be attributed to complete re-epithelialization of keratinocytes. Hence, LGI3 might be considered as a new potential therapeutic target for restoring skin barrier function in AD.

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