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1.
Nano Lett ; 24(32): 9889-9897, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-38985008

RESUMEN

Recently, 2D semiconductor-based optoelectronic memory has been explored to overcome the limitations of conventional von Neumann architectures by integrating optical sensing and data storage into one device. Persistent photocurrent (PPC), essential for optoelectronic memory, originates from charge carrier trapping according to the Shockley-Read-Hall (SRH) model in 2D semiconductors. The quasi-Fermi level position influences the activation of charge-trapping sites. However, the correlation between quasi-Fermi level modulations and PPC in 2D semiconductors has not been extensively studied. In this study, we demonstrate optoelectronic memory based on a 2D semiconductor-polymer hybrid structure and confirm that the underlying mechanism is charge trapping, as the SRH model explains. Under light illumination, electrons transfer from polyvinylpyrrolidone to p-type tungsten diselenide, resulting in high-level injection and majority carrier-type transitions. The quasi-Fermi level shifts upward with increasing temperature, improving PPC and enabling optoelectronic memory at 433 K. Our findings offer valuable insights into optimizing 2D semiconductor-based optoelectronic memory.

2.
Sensors (Basel) ; 21(6)2021 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-33799769

RESUMEN

A novel capacitive humidity sensor based on carbon black/polyimide composites is presented in this paper. The details of the fabrication, sensor characteristics, and effect of the carbon black additive are described. It was confirmed that the polyimide composite filled with a tiny amount of carbon black was suitable for a humidity sensing dielectric. The humidity sensors with three different dielectrics, which were pure polyimide, 0.01 wt% carbon black/polyimide, and 0.05 wt% carbon black/polyimide, were fabricated by a micro-electro-mechanical-system (MEMS) process. As the amount of the carbon black additive increased, the sensitivity of the humidity sensor increased. The humidity sensor with 0.05 wt% of carbon black had a much higher sensitivity of 15.21% (20-80% RH, 0.2535%/% RH) than that of the sensor with pure polyimide, which was 9.73% (0.1622%/% RH). The addition of carbon black also led to an enhancement in the hysteresis and response speed. The hysteresis of the humidity sensor decreased from 2.17 to 1.80% when increasing the amount of the carbon black additive. The response speed of the humidity sensor with 0.05 wt% of carbon black was measured to be ~10% faster than that of the sensor with pure polyimide. The long-term stability of the humidity sensors was demonstrated as well.

3.
Sensors (Basel) ; 21(20)2021 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-34696057

RESUMEN

In this study, we aimed to develop a new automated method for kidney volume measurement in children using ultrasonography (US) with image pre-processing and hybrid learning and to formulate an equation to calculate the expected kidney volume. The volumes of 282 kidneys (141 subjects, <19 years old) with normal function and structure were measured using US. The volumes of 58 kidneys in 29 subjects who underwent US and computed tomography (CT) were determined by image segmentation and compared to those calculated by the conventional ellipsoidal method and CT using intraclass correlation coefficients (ICCs). An expected kidney volume equation was developed using multivariate regression analysis. Manual image segmentation was automated using hybrid learning to calculate the kidney volume. The ICCs for volume determined by image segmentation and ellipsoidal method were significantly different, while that for volume calculated by hybrid learning was significantly higher than that for ellipsoidal method. Volume determined by image segmentation was significantly correlated with weight, body surface area, and height. Expected kidney volume was calculated as (2.22 × weight (kg) + 0.252 × height (cm) + 5.138). This method will be valuable in establishing an age-matched normal kidney growth chart through the accumulation and analysis of large-scale data.


Asunto(s)
Inteligencia Artificial , Tomografía Computarizada por Rayos X , Adulto , Niño , Humanos , Procesamiento de Imagen Asistido por Computador , Riñón/diagnóstico por imagen , Ultrasonografía , Adulto Joven
4.
J Biomol NMR ; 74(6-7): 311-319, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32415582

RESUMEN

Monoclonal antibody (mAb) drugs are clinically important for the treatment of various diseases. TTAC-0001 is under development as a new anti-cancer antibody drug targeting VEGFR-2. As the less severe toxicity of TTAC-0001 compared to Bevacizumab, likely due to the decreased in vivo half-life, seems to be related to its structural flexibility, it is important to map the exact flexible regions. Although the 13C/15N-labeled protein is required for NMR analyses, it is difficult to obtain antibody fragments (Fab and scFv) containing disulfide bonds through general cytosolic expression in Escherichia coli (E. coli). Here, we notably increased the periplasmic expression of the 13C/15N-labeled TTAC-0001-Fab (13C/15N-TTAC-Fab) through simple isopropyl ß-D-1-thiogalactopyranoside (IPTG)-induction at an increased optical density (1.5 OD600nm). Through NMR triple resonance experiments, two loop insertions (LI-1 between the VH and CH1; LI-2 between the VL and CL) were confirmed to be highly flexible. The additional LIs could be another way to engineer the antibody by changing the pharmacokinetic properties.


Asunto(s)
Anticuerpos Monoclonales Humanizados/química , Anticuerpos Monoclonales Humanizados/metabolismo , Resonancia Magnética Nuclear Biomolecular/métodos , Anticuerpos Monoclonales Humanizados/genética , Isótopos de Carbono , Disulfuros/química , Escherichia coli/genética , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/genética , Fragmentos Fab de Inmunoglobulinas/metabolismo , Isopropil Tiogalactósido , Marcaje Isotópico , Isótopos de Nitrógeno , Periplasma/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reproducibilidad de los Resultados , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo
5.
IEEE Trans Electron Devices ; 63(10): 3851-3856, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28579633

RESUMEN

We report a new technique for the rapid measurement of full capacitance-voltage (C-V) characteristic curves. The displacement current from a 100 MHz applied sine-wave, which swings from accumulation to strong inversion, is digitized directly using an oscilloscope from the metal-oxide-semiconductor (MOS) capacitor under test. A C-V curve can be constructed directly from this data but is severely distorted due to non-ideal behavior of real measurement systems. The key advance of this work is to extract the system response function using the same measurement set-up and a known MOS capacitor. The system response correction to the measured C-V curve of the unknown MOS capacitor can then be done by simple deconvolution. No de-skewing and/or leakage current correction is necessary, making it a very simple and quick measurement. Excellent agreement between the new fast C-V method and C-V measured conventionally by an LCR meter is achieved. The total time required for measurement and analysis is approximately 2 seconds, which is limited by our equipment.

6.
J Neurochem ; 132(2): 254-62, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25156412

RESUMEN

The functional roles of the orphan nuclear receptor, Nurr1, have been extensively studied and well established in the development and survival of midbrain dopamine neurons. As Nurr1 and other NR4A members are widely expressed in the brain in overlapping and distinct manners, it has been an open question whether Nurr1 has important function(s) in other brain areas. Recent studies suggest that up-regulation of Nurr1 expression is critical for cognitive functions and/or long-term memory in forebrain areas including hippocampal formation. Questions remain about the association between Nurr1 expression and Alzheimer's disease (AD) brain pathology. Here, using our newly developed Nurr1-selective antibody, we report that Nurr1 protein is prominently expressed in brain areas with Aß accumulation, that is, the subiculum and the frontal cortex, in the 5XFAD mouse and that Nurr1 is highly co-expressed with Aß at early stages. Furthermore, the number of Nurr1-expressing cells significantly declines in the 5XFAD mouse in an age-dependent manner, accompanied by increased plaque deposition. Thus, our findings suggest that altered expression of Nurr1 is associated with AD progression. Using our newly developed Nurr1-selective antibody, we show that Nurr1 protein is prominently expressed in brain areas accumulating amyloid-beta (Aß) in the transgenic mouse model of Alzheimer's disease (AD) and that Nurr1 is highly co-expressed with Aß at early stages (upper panel). Furthermore, in the AD brain the number of Nurr1-expressing cells significantly declines in an age-dependent manner concomitant with increased Aß accumulation (lower diagram) highlighting a possible Nurr1 involvement in AD pathology.


Asunto(s)
Péptidos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Corteza Cerebral/metabolismo , Hipocampo/metabolismo , Proteínas del Tejido Nervioso/fisiología , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/fisiología , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Secuencia de Aminoácidos , Animales , Especificidad de Anticuerpos , Corteza Cerebral/patología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Técnica del Anticuerpo Fluorescente Directa , Hipocampo/patología , Técnicas para Inmunoenzimas , Ratones , Ratones Transgénicos , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/biosíntesis , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/inmunología , Alineación de Secuencia , Homología de Secuencia de Aminoácido
7.
Environ Microbiol ; 17(11): 4511-26, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26014207

RESUMEN

Pseudomonas aeruginosa is a highly successful nosocomial pathogen capable of causing a wide variety of infections with clone C strains most prevalent worldwide. In this study, we initially characterize a molecular mechanism of survival unique to clone C strains. We identified a P. aeruginosa clone C-specific genomic island (PACGI-1) that contains the highly expressed small heat shock protein sHsp20c, the founding member of a novel subclass of class B bacterial small heat shock proteins. sHsp20c and adjacent gene products are involved in resistance against heat shock. Heat stable sHsp20c is unconventionally expressed in stationary phase in a wide temperature range from 20 to 42°C. Purified sHsp20c has characteristic features of small heat shock protein class B as it is monodisperse, forms sphere-like 24-meric oligomers and exhibits significant chaperone activity. As the P. aeruginosa clone C population is significantly more heat shock resistant than genetically unrelated P. aeruginosa strains without sHsp20c, the horizontally acquired shsp20c operon might contribute to the survival of worldwide-distributed clone C strains.


Asunto(s)
Islas Genómicas/genética , Proteínas de Choque Térmico/genética , Respuesta al Choque Térmico/fisiología , Pseudomonas aeruginosa/genética , Secuencia de Aminoácidos , Secuencia de Bases , Infección Hospitalaria/microbiología , ADN Bacteriano/genética , Calor , Datos de Secuencia Molecular , Pseudomonas aeruginosa/clasificación , Pseudomonas aeruginosa/metabolismo , Análisis de Secuencia de ADN
8.
Anal Chem ; 87(9): 4910-6, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25867553

RESUMEN

Electron spin resonance (ESR) spectroscopy's affinity for detecting paramagnetic free radicals, or spins, has been increasingly employed to examine a large variety of biochemical interactions. Such paramagnetic species are broadly found in nature and can be intrinsic (defects in solid-state materials systems, electron/hole pairs, stable radicals in proteins) or, more often, purposefully introduced into the material of interest (doping/attachment of paramagnetic spin labels to biomolecules of interest). Using ESR to trace the reactionary path of paramagnetic spins or spin-active proxy molecules provides detailed information about the reaction's transient species and the label's local environment. For many biochemical systems, like those involving membrane proteins, synthesizing the necessary quantity of spin-labeled biomolecules (typically 50 pmol to 100 pmol) is quite challenging and often limits the possible biochemical reactions available for investigation. Quite simply, ESR is too insensitive. Here, we demonstrate an innovative approach that greatly enhances ESR's sensitivity (>20000× improvement) by developing a near-field, nonresonant, X-band ESR spectrometric method. Sensitivity improvement is confirmed via measurement of 140 amol of the most common nitroxide spin label in a ≈593 fL liquid cell at ambient temperature and pressure. This experimental approach eliminates many of the typical ESR sample restrictions imposed by conventional resonator-based ESR detection and renders the technique feasible for spatially resolved measurements on a wider variety of biochemical samples. Thus, our approach broadens the pool of possible biochemical and structural biology studies, as well as greatly enhances the analytical power of existing ESR applications.


Asunto(s)
Proteínas de la Membrana/análisis , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/análisis , Microondas
9.
Arthritis Rheum ; 65(4): 1055-63, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23335107

RESUMEN

OBJECTIVE: Several copy number variations (CNVs) have been found to be associated with systemic lupus erythematosus (SLE) through the target gene approach. However, genome-wide features of CNVs and their role in the risk of SLE remain unknown. The aim of this study was to identify SLE-associated CNVs in Korean women. METHODS: Genome-wide assessments of CNVs were performed in 382 SLE patients and 191 control subjects, using an Illumina HumanHap610 BeadChip genotyping platform. SLE-associated CNV regions that were identified by genome-wide association study (GWAS) were replicated in quantitative polymerase chain reaction (PCR) and deletion-typing PCR analyses in an independent sample set comprising 564 SLE patients and 511 control subjects. RESULTS: Of 144 common CNV regions, 3 deletion-type CNV regions in 1q25.1, 8q23.3, and 10q21.3 were found to be significantly associated with SLE by GWAS analysis. In the independent replication, the CNV regions in 1q25.1 (RABGAP1L) and 10q21.3 were successfully replicated (odds ratio [OR] 1.30, P=0.038 and OR 1.90, P=3.6×10(-5), respectively), and the associations were confirmed again by deletion-typing PCR. The CNV region in the C4 gene, which showed a potential association in the discovery stage, was included in the replication analysis and was found to be significantly associated with the risk of SLE (OR 1.88, P=0.01). Through deletion-typing PCR, the exact sizes and breakpoint sequences of the deletions were defined. Individuals with the deletions in all 3 loci (RABGAP1L, 10q21.3, and C4) had a much higher risk of SLE than did those without any deletions in the 3 loci (OR 5.52, P=3.9×10(-4)). CONCLUSION: These CNV regions can be useful to identify the pathogenic mechanisms of SLE, and might be used to more accurately predict the risk of SLE by taking into consideration their synergistic effects on disease susceptibility.


Asunto(s)
Secuencia de Bases/genética , Cromosomas Humanos Par 10/genética , Cromosomas Humanos Par 8/genética , Complemento C4/genética , Proteínas Activadoras de GTPasa/genética , Lupus Eritematoso Sistémico/genética , Proteínas del Tejido Nervioso/genética , Eliminación de Secuencia/genética , Adulto , Pueblo Asiatico/genética , Estudios de Casos y Controles , Variaciones en el Número de Copia de ADN , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Genotipo , Humanos , Oportunidad Relativa , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , República de Corea , Factores de Riesgo , Adulto Joven
10.
Nutr Res Pract ; 18(4): 523-533, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39109196

RESUMEN

BACKGROUND/OBJECTIVES: Given that adolescents watch Mukbang (eating broadcast) more frequently than other age groups, interest in the potential health effects of watching Mukbang and Cookbang (cooking broadcast) is growing. This study aimed to determine the status of watching Mukbang and Cookbang among Korean adolescents and its relationship with their dietary behaviors. SUBJECTS/METHODS: We used data from the 18th Korea Youth Risk Behavior Survey, conducted in 2022 (n = 51,850). The study included the frequency of watching Mukbang and Cookbang and the self-rated impact of watching them. Dietary behaviors included consumption of the following items: fruits (≥ once a day), vegetables (≥ 3 times a day), fast foods (≥ 3 times a week), late-night snacks (≥ 3 times a week), caffeinated drinks (≥ 3 times a week), and sweet-flavored drinks (≥ 3 times a week). Furthermore, obesity, weight loss attempts during the past 30 days, body image distortion, and inappropriate methods to control weight were also included. RESULTS: Among adolescents, 70.6% watched Mukbang and Cookbang, and 13.2% watched them more than 5 times a week. Approximately 27.6% of the adolescents responded that they were influenced by watching Mukbang and Cookbang. Adolescents who frequently watched Mukbang and Cookbang consumed less vegetable and fruit; however, the likelihood of consuming fast food, late-night snacks, sugary drinks, and caffeinated drinks increased. In addition, they were more likely to attempt inappropriate weight-loss methods and become obese. Adolescents who responded that their eating habits were influenced by watching Mukbang and Cookbang were more likely to have unhealthy eating behavior compared to the group who responded that their habits were not influenced by these shows. CONCLUSION: Watching Mukbang and Cookbang is common among Korean adolescents and is associated with unhealthy dietary behaviors. Prospective studies, including broadcasting content, should evaluate the impact of Mukbang and Cookbang on health.

11.
Pharmacol Rep ; 76(2): 368-378, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38498259

RESUMEN

BACKGROUND: Excessive stress, a major problem in modern societies, affects people of all ages worldwide. Corticosterone is one of the most abundant hormones secreted during stressful conditions and is associated with various dysfunctions in the body. In particular, we aimed to investigate the protective effects of hygrolansamycin C (HYGC) against corticosterone-induced cellular stress, a manifestation of excessive stress prevalent in contemporary societies. METHODS: We isolated HYGC from Streptomyces sp. KCB17JA11 and subjected PC12 cells to corticosterone-induced stress. The effects of HYGC were assessed by measuring autophagy and the expression of mitogen-activated protein kinase (MAPK) phosphorylation-related genes. We used established cellular and molecular techniques to analyze protein levels and pathways. RESULTS: HYGC effectively protected cells against corticosterone-induced injury. Specifically, it significantly reduced corticosterone-induced oxidative stress and inhibited the expression of autophagy-related proteins induced by corticosterone, which provided mechanistic insight into the protective effects of HYGC. At the signaling level, HYGC suppressed c-Jun N-terminal kinase and extracellular signal-regulated kinase phosphorylation and p38 activation. CONCLUSIONS: HYGC is a promising candidate to counteract corticosterone-induced apoptosis and oxidative stress. Autophagy and MAPK pathway inhibition contribute to the protective effects of HYGC. Our findings highlight the potential of HYGC as a therapeutic agent for stress-related disorders and serve as a stepping stone for further exploration and development of stress management strategies.


Asunto(s)
Corticosterona , Proteínas Quinasas p38 Activadas por Mitógenos , Ratas , Animales , Humanos , Corticosterona/toxicidad , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Sistema de Señalización de MAP Quinasas , Estrés Oxidativo , Transducción de Señal , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Apoptosis , Autofagia
12.
Adv Sci (Weinh) ; 11(25): e2308662, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38666427

RESUMEN

Cancer vaccines offer a promising avenue in cancer immunotherapy by inducing systemic, tumor-specific immune responses. Tumor extracellular vesicles (TEVs) are nanoparticles naturally laden with tumor antigens, making them appealing for vaccine development. However, their inherent malignant properties from the original tumor cells limit their direct therapeutic use. This study introduces a novel approach to repurpose TEVs as potent personalized cancer vaccines. The study shows that inhibition of both YAP and autophagy not only diminishes the malignancy-associated traits of TEVs but also enhances their immunogenic attributes by enriching their load of tumor antigens and adjuvants. These revamped TEVs, termed attenuated yet immunogenically potentiated TEVs (AI-TEVs), showcase potential in inhibiting tumor growth, both as a preventive measure and a possible treatment for recurrent cancers. They prompt a tumor-specific and enduring immune memory. In addition, by showing that AI-TEVs can counteract cancer growth in a personalized vaccine approach, a potential strategy is presented for developing postoperative cancer immunotherapy that's enduring and tailored to individual patients.


Asunto(s)
Vacunas contra el Cáncer , Vesículas Extracelulares , Medicina de Precisión , Vesículas Extracelulares/inmunología , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/uso terapéutico , Animales , Ratones , Medicina de Precisión/métodos , Humanos , Modelos Animales de Enfermedad , Inmunoterapia/métodos , Neoplasias/inmunología , Neoplasias/terapia , Línea Celular Tumoral , Antígenos de Neoplasias/inmunología , Femenino
13.
Bioinformatics ; 28(13): 1790-2, 2012 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-22539667

RESUMEN

SUMMARY: The method for genome-wide association study (GWAS) based on copy number variation (CNV) is not as well established as that for single nucleotide polymorphism (SNP)-GWAS. Although there are several tools for CNV association studies, most of them do not provide appropriate definitions of CNV regions (CNVRs), which are essential for CNV-association studies. Here we present a user-friendly program called CNVRuler for CNV-association studies. Outputs from the 10 most common CNV defining algorithms can be directly used as input files for determining the three different definitions of CNVRs. Once CNVRs are defined, CNVRuler supports four kinds of statistical association tests and options for population stratification. CNVRuler is based on the open-source programs R and Java from Sun Microsystems. AVAILABILITY: CNVRuler software is available with an online manual at the website, www.ircgp.com/CNVRuler/index.html.


Asunto(s)
Variaciones en el Número de Copia de ADN , Estudio de Asociación del Genoma Completo , Programas Informáticos , Algoritmos , Estudios de Casos y Controles
14.
Materials (Basel) ; 16(9)2023 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-37176474

RESUMEN

This study aims to improve the economic efficiency of the pitch synthesis reaction on the pilot plant by optimizing the pitch synthesis reaction and utilization of the byproduct. The pitch was synthesized using a 150 L pilot plant with pyrolyzed fuel oil as a precursor. The pitch synthesis reaction is carried out through volatilization and polycondensation, which occur at 300 and 400 °C. Volatilization is terminated during heating; thus, additional soaking time is meaningless and reduces the process efficiency. Soaking time is a major variable when the synthesis temperature exceeds 400 °C. The byproduct is generated through volatilization; thus, its chemical characteristics are only influenced by the reaction temperature. The byproduct consists of various polycyclic aromatic hydrocarbons. The average molecular weight and yield of the byproduct increase with the reaction temperature. Carbon black was synthesized using chemical vapor deposition from the byproduct. The particle size of carbon black was controlled by the used precursor (byproduct), and the electrical conductivity of prepared carbon black has a maximum of 58.0 S/cm. Therefore, carbon black, which is synthesized from the byproduct of pitch synthesis, is expected to be used as a precursor for conductive material used in lithium-ion batteries or supercapacitors.

15.
Micromachines (Basel) ; 14(5)2023 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-37241589

RESUMEN

Aluminum nitride (AlN) thin film/molybdenum (Mo) electrode structures are typically required in microelectromechanical system applications. However, the growth of highly crystalline and c-axis-oriented AlN thin films on Mo electrodes remains challenging. In this study, we demonstrate the epitaxial growth of AlN thin films on Mo electrode/sapphire (0001) substrates and examine the structural characteristics of Mo thin films to determine the reason contributing to the epitaxial growth of AlN thin films on Mo thin films formed on sapphire. Two differently oriented crystals are obtained from Mo thin films grown on sapphire substrates: (110)- and (111)-oriented crystals. The dominant (111)-oriented crystals are single-domain, and the recessive (110)-oriented crystals comprise three in-plane domains rotated by 120° with respect to each other. The highly ordered Mo thin films formed on sapphire substrates serve as templates for the epitaxial growth by transferring the crystallographic information of the sapphire substrates to the AlN thin films. Consequently, the out-of-plane and in-plane orientation relationships among the AlN thin films, Mo thin films, and sapphire substrates are successfully defined.

16.
Materials (Basel) ; 16(11)2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37297218

RESUMEN

In this paper, a method for optimizing the mixing ratio of filler coke and binder for high-strength carbon-carbon composites is proposed. Particle size distribution, specific surface area, and true density were analyzed to characterize the filler properties. The optimum binder mixing ratio was experimentally determined based on the filler properties. As the filler particle size was decreased, a higher binder mixing ratio was required to enhance the mechanical strength of the composite. When the d50 particle size of the filler was 62.13 and 27.10 µm, the required binder mixing ratios were 25 and 30 vol.%, respectively. From this result, the interaction index, which quantifies the interaction between the coke and binder during carbonization, was deduced. The interaction index had a higher correlation coefficient with the compressive strength than that of the porosity. Therefore, the interaction index can be used in predicting the mechanical strength of carbon blocks and optimizing their binder mixing ratios. Furthermore, as it is calculated from the carbonization of blocks without additional analysis, the interaction index can be easily used in industrial applications.

17.
Materials (Basel) ; 16(21)2023 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-37959493

RESUMEN

We investigate the reassembly techniques for utilizing fine graphite particles, smaller than 5 µm, as high-efficiency, high-rate anode materials for lithium-ion batteries. Fine graphite particles of two sizes (0.4-1.2 µm and 5 µm) are utilized, and the mixing ratio of the two particles is varied to control the porosity of the assembled graphite. The packing characteristics of the assembled graphite change based on the mixing ratio of the two types of fine graphite particles, forming assembled graphite with varying porosities. The open porosity of the manufactured assembled graphite samples ranges from 0.94% to 3.55%, while the closed porosity ranges from 21.41% to 26.51%. All the assembled graphite shows improved electrochemical characteristics properties compared with anodes composed solely of fine graphite particles without granulation. The sample assembled by mixing 1.2 µm and 5 µm graphite at a 60:40 ratio exhibits the lowest total porosity (27.45%). Moreover, it exhibits a 92.3% initial Coulombic efficiency (a 4.7% improvement over fine graphite particles) and a capacity of 163.4 mAh/g at a 5C-rate (a 1.9-fold improvement over fine graphite particles).

18.
Micromachines (Basel) ; 14(5)2023 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-37241599

RESUMEN

In this study, a subminiature implantable capacitive pressure sensor is proposed for biomedical applications. The proposed pressure sensor comprises an array of elastic silicon nitride (SiN) diaphragms formed by the application of a polysilicon (p-Si) sacrificial layer. In addition, using the p-Si layer, a resistive temperature sensor is also integrated into one device without additional fabrication steps or extra cost, thus enabling the device to measure pressure and temperature simultaneously. The sensor with a size of 0.5 × 1.2 mm was fabricated using microelectromechanical systems (MEMS) technology and was packaged in needle-shaped metal housing that is both insertable and biocompatible. The packaged pressure sensor immersed in a physiological saline solution exhibited excellent performance without leakage. The sensor achieved a sensitivity of approximately 1.73 pF/bar and a hysteresis of about 1.7%, respectively. Furthermore, it was confirmed that the pressure sensor operated normally for 48 h without experiencing insulation breakdown or degradation of the capacitance. The integrated resistive temperature sensor also worked properly. The response of the temperature sensor varied linearly with temperature variation. It had an acceptable temperature coefficient of resistance (TCR) of approximately 0.25%/°C.

19.
Hum Mol Genet ; 19(6): 1001-8, 2010 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-20026555

RESUMEN

Recent discovery of the copy number variation (CNV) in normal individuals has widened our understanding of genomic variation. However, most of the reported CNVs have been identified in Caucasians, which may not be directly applicable to people of different ethnicities. To profile CNV in East-Asian population, we screened CNVs in 3578 healthy, unrelated Korean individuals, using the Affymetrix Genome-Wide Human SNP array 5.0. We identified 144,207 CNVs using a pooled data set of 100 randomly chosen Korean females as a reference. The average number of CNVs per genome was 40.3, which is higher than that of CNVs previously reported using lower resolution platforms. The median size of CNVs was 18.9 kb (range 0.2-5406 kb). Copy number losses were 4.7 times more frequent than copy number gains. CNV regions (CNVRs) were defined by merging overlapping CNVs identified in two or more samples. In total, 4003 CNVRs were defined encompassing 241.9 Mb accounting for approximately 8% of the human genome. A total of 2077 CNVRs (51.9%) were potentially novel. Known CNVRs were larger and more frequent than novel CNVRs. Sixteen percent of the CNVRs were observed in > or =1% of study subjects and 24% overlapped with the OMIM genes. A total of 476 (11.9%) CNVRs were associated with segmental duplications. CNVS/CNVRs identified in this study will be valuable resources for studying human genome diversity and its association with disease.


Asunto(s)
Pueblo Asiatico/genética , Variaciones en el Número de Copia de ADN/genética , Evolución Molecular , Genética de Población , Secuencia de Bases , Cromosomas Humanos/genética , Bases de Datos Genéticas , Asia Oriental/etnología , Femenino , Frecuencia de los Genes/genética , Genes , Genoma Humano/genética , Humanos , Masculino , Retroelementos/genética
20.
Materials (Basel) ; 15(13)2022 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-35806837

RESUMEN

This study evaluated the effect of pitch coating on graphite anode materials used in lithium-ion batteries and investigated the mechanism whereby pitch coating improves the electrochemical properties. The FG (flake graphite) and pitch were mixed in weight ratios of 95:5-80:20. The mixture was pressed and prepared into a block form. Additionally, heat treatment was performed at 900 °C for 1 h and pulverized in the size range of 10-25 µm. The results showed that the particles of uniform pitch-coated graphite became more spherical. However, when the pitch is added excessively, pitch aggregation occurs rather than a thicker coating, indicating a nonuniform particle shape. Pitch has a randomly oriented structure and a small crystal size. Therefore, pitch serves as a lithium-ion diffusion pathway, resulting in an improved rate of performance. Notably, the uniform pitch-coated graphite exhibited an outstanding rate of performance owing to the relieving of particle orientation in the electrode rolling process. During the rolling process, the particles are oriented perpendicular to the lithium-ion diffusion pathway, making it difficult for the lithium ions to diffuse. Adding an excessive amount of pitch was found to deteriorate the rate of performance. Pitch aggregation increased the interfacial resistance by forming a heterogeneous surface.

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