Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 323
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Vascular ; : 17085381241261752, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38905636

RESUMEN

OBJECTIVES: Although the medical field has made significant progress, there has been little improvement in the survival rate of patients with ruptured abdominal aortic aneurysms (rAAAs). We implemented a protocol consisting of five strategies in the management of rAAA patients who underwent open repair surgery. METHODS: The protocol comprised the following strategies: intentional hypotension <70 mmHg, lung first and kidney last policy (restricted fluid resuscitation and permissive oligoanuria), immediate postoperative extubation, free-water intake with active ambulation, and open abdomen with the routine second-look operation. The study included 13 patients (11 male) with a mean age of 75.5 ± 7.4 (range: 58-87) years who underwent the procedure from 2016 to 2018, with a mean follow-up of 40.1 ± 9.04 months. Five deteriorating to hemodynamic shock and decreased consciousness requiring intubation and ventilation prior to surgery were observed. Two of these patients required preoperative cardiopulmonary resuscitation (CPR). RESULTS: All patients regained consciousness after surgery, including the two patients who required cardiopulmonary resuscitation. Immediate postoperative extubation was performed in nine patients, but two (22.2%) of them needed re-intubation due to ventilation/perfusion mismatch. Four patients underwent continuous renal replacement therapy, with three of them having anuria for up to 48 h after surgery. Two of these patients made a full recovery. Daily ambulation was carried out for a mean of 4.77 ± 3.5 (range 1-13) days with an open abdomen, during which no significant events were reported. Four cases of colon ischemia/necrosis were identified in the second-look operation, with two patients requiring Hartman's procedure and the other two undergoing left colon partial resection. There were two in-hospital mortalities (15.4%). CONCLUSIONS: A protocol-based approach, through multidisciplinary team consensus and the development of optimal surgical strategies, could improve clinical outcomes for patients undergoing emergency surgery for rAAA. Further studies with larger sample sizes are needed to refine the protocols.

2.
Nanotechnology ; 34(40)2023 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-37399798

RESUMEN

Highly purified and solution-processed semiconducting carbon nanotubes (s-CNTs) have developed rapidly over the past several decades and are near-commercially available materials that can replace silicon due to its large-area substrate deposition and room-temperature processing compatibility. However, the more s-CNTs are purified, the better their electrical performance, but considerable effort and long centrifugation time are required, which can limit commercialization due to high manufacturing costs. In this work, we therefore fabricated 'striped' CNT network transistor across industry-standard 8 inch wafers. The stripe-structured channel is effective in lowering the manufacturing cost because it can maintain good device performance without requiring high-purity s-CNTs. We evaluated the electrical performances and their uniformity by demonstrating striped CNT network transistors fabricating from various s-CNT solutions (e.g. 99%, 95%, and 90%) in 8 inch wafers. From our results, we concluded that by optimizing the CNT network configurations, CNTs can be sufficiently utilized for commercialization technology even at low semiconducting purity. Our approach can serve as a critical foundation for future low-cost commercial CNT electronics.

3.
Int J Mol Sci ; 24(15)2023 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-37569708

RESUMEN

Ulcerative colitis is an inflammatory bowel disease characterized by inflammation in the mucosal and submucosal layers of the colon. Obesity is closely related to the occurrence and progression of colitis. The most plausible mechanism linking obesity and colitis is an excessive adipogenesis-related inflammatory response, which causes mucosal dysfunction. Obesity and colitis are linked by several etiologic mechanisms, including excessive adipogenesis, lipotoxicity, pro-inflammatory adipokines/cytokines, macrophage polarization, oxidative stress, endoplasmic reticulum (ER) stress, and gut microbiota. These low-grade enteric inflammations cause mucosal layer damage, especially goblet cell dysfunction through mucin 2 (MUC2) misfolding, ultimately leading to colitis. Inhibiting the inflammatory response can be the most effective approach for treating obesity-related colitis. We focused on the anti-inflammatory effects of polyphenols in Protaectia brevitas larvae. The P. brevitas was prepared as a low molecular protein hydrolysate (PHPB) to increase the concentration of anti-inflammatory molecules. In the current study, we investigated the anti-inflammatory effect of PHPB in an obesity-induced colitis mouse model. Compared with the high-fat diet (HFD) group, the group treated with PHPB exhibited reduced body/organ/fat weight, appetite/food intake inhibition, hypolipidemic effect on ectopic fat, and anti-adipogenic mechanism through the AMPK signaling pathway. Furthermore, we observed attenuated expression of PPARγ and C/EBPα, inhibition of pro-inflammatory molecules, stimulation of anti-inflammatory molecules, probiotic-like effect against obesogenic gut microbiota, inhibition of macrophage polarization into M1, suppression of oxidative/ER stress, and reduction of Muc2 protein misfolding in colon. These diverse anti-inflammatory responses caused histological and functional recovery of goblet cells, eventually improving colitis. Therefore, our findings suggest that the protein hydrolysate of Protaetia brevitarsis can improve obesity-related colitis through its anti-inflammatory activities.


Asunto(s)
Colitis , Hidrolisados de Proteína , Ratones , Animales , Dieta Alta en Grasa/efectos adversos , Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Colitis/metabolismo , Inflamación , Obesidad/tratamiento farmacológico , Antiinflamatorios/efectos adversos , Ratones Endogámicos C57BL
4.
J Minim Access Surg ; 19(3): 443-446, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36695241

RESUMEN

Desmoid tumours are rare tumours originating from fibroblasts, and are characterised by local infiltration and no metastasis. When complete resection is possible, surgical resection is considered a first-line treatment. In the case of large desmoid tumours, it is mainly performed by laparotomy, not laparoscopy. We report a case of a 43-year-old female patient presenting with a hypodense mass of approximately 5 cm in the posterior wall of the gastric antrum on computed tomography. There was no history of familial adenomatous polyposis, trauma or abdominal surgery. The patient underwent laparoscopic gastric wedge resection and spleen-preserving distal pancreatectomy without peri-operative complications. Pathological analysis revealed a desmoid tumour, which originated from the stomach and invaded the pancreas. Despite the large size and the locally infiltrative characteristics of these tumours, laparoscopic surgery can be an optimal treatment option due to its advantages.

5.
Nanotechnology ; 33(24)2022 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-35259734

RESUMEN

Carbon nanotubes (CNTs) are one-dimensional materials that have been proposed to replace silicon semiconductors and have been actively studied due to their high carrier mobility, high current density, and high mechanical flexibility. Specifically, highly purified, pre-separated, and solution-processed semiconducting CNTs are suitable for mass production. These CNTs have advantages, such as room-temperature processing compatibility, while enabling a fast and straightforward manufacturing process. In this paper, CNT network transistors were fabricated on a total of five 8 inch wafers by reusing a highly purified and pre-separated 99% semiconductor-enriched CNT solution. The results confirmed that the density of semiconducting CNTs deposited on the five selected wafers was notably uniform, even though the CNT solution was reused up to four times after the initial CNT deposition. Moreover, there was no significant degradation in the key CNT network transistor metrics. Therefore, we believe that our findings regarding this CNT reuse method may provide additional guidance in the field of wafer-scale CNT electronics and may contribute strongly to the development of practical device applications at an ultralow cost.

6.
Int J Mol Sci ; 23(9)2022 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-35563670

RESUMEN

The orphan nuclear receptor 4A1 (NR4A1) is highly expressed in human pancreatic cancer cells and exerts pro-oncogenic activity. In a previous study, we demonstrated that fangchinoline (FCN), a natural inhibitor of nuclear NR4A1, induces NR4A1-dependent apoptosis in human pancreatic cancer cells. In this study, we evaluated FCN and its structural analogs (berbamine, isotetrandrine, tetrandrine, and tubocurarine) for their inhibitory effects on NR4A1 transactivity, and confirmed that tetrandrine (TTD) showed the highest inhibitory effect in pancreatic cancer cells. Moreover, in a tryptophan fluorescence quenching assay, TTD directly bound to the ligand binding domain (LBD) of NR4A1 with a KD value of 10.60 µM. Treatment with TTD decreased proliferation and induced apoptosis in Panc-1 human pancreatic cancer cells in part through the reduced expression of the Sp1-dependent anti-apoptotic gene survivin and induction of ROS-mediated endoplasmic reticulum stress, which are the well-known NR4A1-dependent proapoptotic pathways. Furthermore, at a dose of 25 mg/kg/day, TTD reduced tumor growth in an athymic nude mouse xenograft model bearing Panc-1 cells. These data show that TTD is an NR4A1 antagonist and that modulation of the NR4A1-mediated pro-survival pathways is involved in the antitumor effects of TTD.


Asunto(s)
Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares , Neoplasias Pancreáticas , Animales , Apoptosis , Bencilisoquinolinas , Línea Celular Tumoral , Proliferación Celular , Humanos , Ratones , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas
7.
Medicina (Kaunas) ; 58(2)2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-35208589

RESUMEN

Central venous cannulation (CVC) is a procedure that is frequently performed to facilitate resuscitation, nutritional support and long-term vascular access. It may often cause mechanical complications during placement of a cannula in association with the anatomical relationship with central veins. A 68-year-old man visited our medical institution with a chief complaint of foreign-body-induced esophageal perforation. This patient presented with bleeding of the superior vena cava due to an iatrogenic injury to it during the CVC in the right internal jugular vein. Our case indicates that it would be mandatory to insert a cannula at an optimal depth considering the anatomical relationship between the central veins during the CVC.


Asunto(s)
Cateterismo Venoso Central , Vena Cava Superior , Anciano , Cateterismo Venoso Central/efectos adversos , Cateterismo Venoso Central/métodos , Humanos , Enfermedad Iatrogénica , Venas Yugulares/diagnóstico por imagen , Masculino , Ultrasonografía Intervencional , Vena Cava Superior/diagnóstico por imagen
8.
Eur Spine J ; 30(2): 534-546, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33078265

RESUMEN

PURPOSE: Cervical radiculopathy is a common disabling cervical spine condition. Open anterior and posterior approaches are the conventional surgical treatment approaches with good clinical outcomes. However, the soft tissue damage in these procedures can lead to increase perioperative morbidity. Endoscopic spine surgery provides more soft tissue preservation than conventional approaches. We investigate the radiological and clinical outcomes of posterior endoscopic cervical foraminotomy and discectomy. METHODS: A prospective clinical and radiological study with retrospective evaluation were done for 25 patients with 29 levels of cervical radiculopathy who underwent posterior endoscopic cervical discectomy from November 2016 to December 2018. Clinical outcomes of Visual Analogue Scale, Neck Disability Index and MacNab's score were evaluated at pre-operative, post-operative 1 week, 3 months and final follow-up. Preoperative and post-operative final follow-up flexion and extension roentgenogram were evaluated for cervical stability assessment. Pre-operative and post-operative computer tomography cervical spine evaluation of foraminal length in ventro-dorsal, cephalad-caudal dimensions, sagittal foraminal area and using 3D CT reconstruction coronal decompression area were done. RESULTS: Twenty-nine levels of cervical radiculopathy underwent posterior endoscopic cervical decompression. The mean follow-up was 29.6 months, and the most common levels affected were C5/6 and C6/7. There was a complication rate of 12% with 2 cases of neurapraxia and one case of recurrent of prolapsed disc. There was no revision surgery in our series. There was significant clinical improvement in Visual Analogue Scale and Neck Disability Index. Prospective comparative study between preoperative and final follow-up mean improvement in VAS score was 5.08 ± 1.75, and NDI was 45.1 ± 13.3. Ninety-two percent of the patients achieved good and excellent results as per MacNab's criteria. Retrospective evaluation of the radiological data showed significant increments of foraminal dimensions: (1) sagittal area increased 21.4 ± 11.2 mm2, (2) CT Cranio Caudal length increased 1.21 ± 1.30 mm and (3) CT ventro-dorsal length increased 2.09 ± 1.35 mm and (4) 3D CT scan reconstruction coronal decompression area increased 536 ± 176 mm2, p < 0.05. CONCLUSION: Uniportal posterior endoscopic cervical foraminotomy and discectomy are safe, efficient and precise choreographed set of technique in the treatment of cervical radiculopathy. It significantly improved clinical outcomes and achieved the objective of increasing in the cervical foramen size in our cohort of patients.


Asunto(s)
Foraminotomía , Radiculopatía , Vértebras Cervicales/diagnóstico por imagen , Vértebras Cervicales/cirugía , Computadores , Descompresión , Discectomía/efectos adversos , Estudios de Seguimiento , Foraminotomía/efectos adversos , Humanos , Estudios Prospectivos , Radiculopatía/diagnóstico por imagen , Radiculopatía/cirugía , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
9.
Proc Natl Acad Sci U S A ; 115(18): E4179-E4188, 2018 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-29581250

RESUMEN

Medical castration that interferes with androgen receptor (AR) function is the principal treatment for advanced prostate cancer. However, clinical progression is universal, and tumors with AR-independent resistance mechanisms appear to be increasing in frequency. Consequently, there is an urgent need to develop new treatments targeting molecular pathways enriched in lethal prostate cancer. Lysine-specific demethylase 1 (LSD1) is a histone demethylase and an important regulator of gene expression. Here, we show that LSD1 promotes the survival of prostate cancer cells, including those that are castration-resistant, independently of its demethylase function and of the AR. Importantly, this effect is explained in part by activation of a lethal prostate cancer gene network in collaboration with LSD1's binding protein, ZNF217. Finally, that a small-molecule LSD1 inhibitor-SP-2509-blocks important demethylase-independent functions and suppresses castration-resistant prostate cancer cell viability demonstrates the potential of LSD1 inhibition in this disease.


Asunto(s)
Redes Reguladoras de Genes , Histona Demetilasas/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/enzimología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Histona Demetilasas/antagonistas & inhibidores , Histona Demetilasas/genética , Humanos , Hidrazinas/farmacología , Masculino , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/patología , Sulfonamidas/farmacología , Transactivadores/genética , Transactivadores/metabolismo
10.
Sensors (Basel) ; 21(14)2021 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-34300589

RESUMEN

In this paper, we propose an optimized structure of thin Cu(In,Ga)Se2 (CIGS) solar cells with a grating aluminum oxide (Al2O3) passivation layer (GAPL) providing nano-sized contact openings in order to improve power conversion efficiency using optoelectrical simulations. Al2O3 is used as a rear surface passivation material to reduce carrier recombination and improve reflectivity at a rear surface for high efficiency in thin CIGS solar cells. To realize high efficiency for thin CIGS solar cells, the optimized structure was designed by manipulating two structural factors: the contact opening width (COW) and the pitch of the GAPL. Compared with an unpassivated thin CIGS solar cell, the efficiency was improved up to 20.38% when the pitch of the GAPL was 7.5-12.5 µm. Furthermore, the efficiency was improved as the COW of the GAPL was decreased. The maximum efficiency value occurred when the COW was 100 nm because of the effective carrier recombination inhibition and high reflectivity of the Al2O3 insulator passivation with local contacts. These results indicate that the designed structure has optimized structural points for high-efficiency thin CIGS solar cells. Therefore, the photovoltaic (PV) generator and sensor designers can achieve the higher performance of photosensitive thin CIGS solar cells by considering these results.

11.
Nano Lett ; 20(7): 4864-4871, 2020 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-32551703

RESUMEN

An organic-inorganic hybrid superlattice with near perfect synergistic integration of organic and inorganic constituents was developed to produce properties vastly superior to those of either moiety alone. The complementary hybrid superlattice is composed of multiple quantum wells of 4-mercaptophenol organic monolayers and amorphous ZnO nanolayers. Within the superlattice, multichannel formation was demonstrated at the organic-inorganic interfaces to produce an excellent-performance field effect transistor exhibiting outstanding field-effect mobility with band-like transport and steep subthreshold swing. Furthermore, mutual stabilizations between organic monolayers and ZnO effectively reduced the performance degradation notorious in exclusively organic and ZnO transistors.

12.
Molecules ; 27(1)2021 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-35011291

RESUMEN

Excessive oxidative stress plays a role in hepatotoxicity and the pathogenesis of hepatic diseases. In our previous study, the phenolic extract of beluga lentil (BLE) showed the most potent in vitro antioxidant activity among extracts of four common varieties of lentils; thus, we hypothesized that BLE might protect liver cells against oxidative stress-induced cytotoxicity. BLE was evaluated for its protective effects against oxidative stress-induced hepatotoxicity in AML12 mouse hepatocytes and BALB/c mice. H2O2 treatment caused a marked decrease in cell viability; however, pretreatment with BLE (25-100 µg/mL) for 24 h significantly preserved the viability of H2O2-treated cells up to about 50% at 100 µg/mL. As expected, BLE dramatically reduced intracellular reactive oxygen species (ROS) levels in a dose-dependent manner in H2O2-treated cells. Further mechanistic studies demonstrated that BLE reduced cellular ROS levels, partly by increasing expression of antioxidant genes. Furthermore, pretreatment with BLE (400 mg/kg) for 2 weeks significantly reduced serum levels of alanine transaminase and triglyceride by about 49% and 40%, respectively, and increased the expression and activity of glutathione peroxidase in CCl4-treated BALB/c mice. These results suggest that BLE protects liver cells against oxidative stress, partly by inducing cellular antioxidant system; thus, it represents a potential source of nutraceuticals with hepatoprotective effects.


Asunto(s)
Antioxidantes/farmacología , Lens (Planta)/química , Hígado/efectos de los fármacos , Hígado/metabolismo , Estrés Oxidativo/efectos de los fármacos , Extractos Vegetales/farmacología , Animales , Antioxidantes/química , Línea Celular , Supervivencia Celular/efectos de los fármacos , Enfermedad Hepática Inducida por Sustancias y Drogas , Modelos Animales de Enfermedad , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Peróxido de Hidrógeno/efectos adversos , Hígado/patología , Ratones , Extractos Vegetales/química , Sustancias Protectoras , Especies Reactivas de Oxígeno/metabolismo
13.
Cancer Sci ; 111(9): 3268-3278, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32533590

RESUMEN

Fibroblast growth factor receptor 4 (FGFR4) is known to induce cancer cell proliferation, invasion, and antiapoptosis through activation of RAS/RAF/ERK and PI3K/AKT pathways, which are also known as major molecular bases of colon cancer carcinogenesis related with epidermal growth factor receptor (EGFR) signaling. However, the interaction between FGFR4 and EGFR signaling in regard to colon cancer progression is unclear. Here, we investigated a potential cross-talk between FGFR4 and EGFR, and the effect of anti-EGFR therapy in colon cancer treatment. To explore the biological roles of FGFR4 in cancer progression, RNA sequencing was carried out using FGFR4 transfected colon cell lines. Gene ontology data showed the upregulation of genes related to EGFR signaling, and we identified that FGFR4 overexpression secretes EGFR ligands such as amphiregulin (AREG) with consequent activation of EGFR and ErbB3. This result was also shown in in vivo study and the cooperative interaction between EGFR and FGFR4 promoted tumor growth. In addition, FGFR4 overexpression reduced cetuximab-induced cytotoxicity and the combination of FGFR4 inhibitor (BLU9931) and cetuximab showed profound antitumor effect compared to cetuximab alone. Clinically, we found the positive correlation between FGFR4 and AREG expression in tumor tissue, but not in normal tissue, from colon cancer patients and these expressions were significantly correlated with poor overall survival in patients treated with cetuximab. Therefore, our results provide the novel mechanism of FGFR4 in connection with EGFR activation and the combination of FGFR4 inhibitor and cetuximab could be a promising therapeutic option to achieve the optimal response to anti-EGFR therapy in colon cancer.


Asunto(s)
Anfirregulina/genética , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Receptor Tipo 4 de Factor de Crecimiento de Fibroblastos/metabolismo , Línea Celular Tumoral , Cetuximab/farmacología , Neoplasias del Colon/patología , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal
14.
Hepatology ; 69(3): 1122-1134, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30230575

RESUMEN

Regulation of the protein stability of epigenetic regulators remains ill-defined despite its potential applicability in epigenetic therapies. The histone H3-lysine 4-methyltransferase MLL4 is an epigenetic transcriptional coactivator that directs overnutrition-induced obesity and fatty liver formation, and Mll4+/- mice are resistant to both. Here we show that the E3 ubiquitin ligase UBE3A targets MLL4 for degradation, thereby suppressing high-fat diet (HFD)-induced expression of the hepatic steatosis target genes of MLL4. In contrast to Mll4+/- mice, Ube3a+/- mice are hypersensitive to HFD-induced obesity and fatty liver development. Ube3a+/-;Mll4+/- mice lose this hypersensitivity, supporting roles of increased MLL4 levels in both phenotypes of Ube3a+/- mice. Correspondingly, our comparative studies with wild-type, Ube3a+/- and Ube3a-/- and UBE3A-overexpressing transgenic mouse livers demonstrate an inverse correlation of UBE3A protein levels with MLL4 protein levels, expression of the steatosis target genes of MLL4, and their decoration by H3-lysine 4-monomethylation, a surrogate marker for the epigenetic action of MLL4. Conclusion: UBE3A indirectly exerts an epigenetic regulation of obesity and steatosis by degrading MLL4. This UBE3A-MLL4 regulatory axis provides a potential therapeutic venue for treating various MLL4-directed pathogeneses, including obesity and hepatic steatosis.


Asunto(s)
Hígado Graso/genética , Regulación de la Expresión Génica/fisiología , N-Metiltransferasa de Histona-Lisina/metabolismo , Hipernutrición/genética , Ubiquitina-Proteína Ligasas/fisiología , Animales , Femenino , Masculino , Ratones
15.
Nanotechnology ; 31(46): 465303, 2020 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-32750684

RESUMEN

Highly purified, preseparated semiconducting carbon nanotubes (CNTs) hold great potential for high-performance CNT network transistors due to their high electrical conductivity, high mechanical strength, and room-temperature processing compatibility. In this paper, we report our recent progress on CNT network transistors integrated on an 8-inch wafer. We observe that the key device performance parameters of CNT network transistors at various locations on an 8-inch wafer are highly uniform and that the device yield is impressive. Therefore, this work validates a promising path toward mass production and will make a significant contribution to the future field of wafer-scale CNT electronics.

16.
Nanotechnology ; 31(32): 32LT01, 2020 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-32320962

RESUMEN

As the emerging demand for electronic devices that are simple, cost effective and capable of rapid fabrication has increased, novel fabrication techniques for designing and manufacturing such devices have attracted remarkable research interest. One method for prototyping these electronic devices is to draw them using a handwriting tool that is commonly available. In this work, we demonstrate a transistor and complementary logic inverter that are directly drawn using a brush and that are based on solution-based materials such as semiconducting carbon nanotubes (CNTs), silver ink and paste, and cross-linked poly(4-vinylphenol) (cPVP). The directly drawn CNT thin-film transistor (TFT) has p-type behavior due to the adsorption of oxygen and moisture, a high current on/off ratio (approximately 103), and a low operating voltage. By employing a solution-based chemical doping treatment with an amine-rich polymer, polyethyleneimine (PEI), that has strong electron-donating ability, the drawn p-type CNT-TFT is successfully converted to an n-type CNT-TFT. Therefore, we fabricate a drawn complementary logic inverter consisting of the p-type CNT-TFT and PEI-treated n-type CNT-TFT and evaluate its electrical performance.

17.
Environ Sci Technol ; 54(11): 6987-6996, 2020 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-32374590

RESUMEN

Recently, various attempts have been made to solve plastic waste problems, such as development of biodegradation without producing pollution. Polystyrene (PS) is the fifth most used plastic in many industries; therefore, degrading PS becomes a critical global issue. Here, we reported Pseudomonas aeruginosa strain DSM 50071, initially isolated from the gut of the superworms, Zophobas atratus, and the PS degradation by Pseudomonas sp. DSM 50071. We examined PS degradation using electronic microscopy and measured changes in atomic composition and contact angles with water droplets on the PS surface that represents a chemical change from hydrophobicity to hydrophilicity. We have further examined chemical structural changes using X-ray photoelectron spectroscopy, Fourier-transform-infrared spectroscopy, and nuclear magnetic resonance (NMR) to confirm the formation of carbonyl groups (C═O) in the oxidation pathway during PS biodegradation. In reverse transcription quantitative polymerase chain reaction analysis, the gene expression level of serine hydrolase (SH) in Pseudomonas sp. DSM 50071 was highly increased during PS degradation, and the enzyme-mediated biodegradation of PS was further confirmed by the SH inhibitor treatment test. Thus, the significance of these findings goes beyond the discovery of a novel function of Pseudomonas sp. DSM 50071 in the gut of superworms, highlighting a potential solution for PS biodegradation.


Asunto(s)
Escarabajos , Microbioma Gastrointestinal , Animales , Biodegradación Ambiental , Larva , Poliestirenos , Pseudomonas/genética
18.
Eur Arch Otorhinolaryngol ; 277(7): 1969-1975, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32170420

RESUMEN

PURPOSE: Epistaxis that is refractory to conservative management can be treated with endoscopic sphenopalatine artery ligation (ESPAL). Although rare, ethmoidal artery (EA) bleeding can be a cause of rebleeding after successful ESPAL. EA bleeding is diagnosed by angiography and can also be identified during surgical exploration. However, since the angiographic embolization of the EA is contraindicated, surgical hemostasis is mandatory. This study investigated whether paranasal sinus (PNS) CT could provide information for predicting EA bleeding without angiography in patients with refractory epistaxis requiring ESPAL. METHODS: Forty-seven patients, who were surgically treated [with ESPAL or EA ligation (EAL)] for refractory epistaxis from March 2010 to June 2019, were retrospectively analyzed. A positive PNS CT finding for EA bleeding was defined as the presence of soft tissue densities having continuity with the EA pathway, accompanied by a partially deficient surrounding bony canal. These findings as well as soft tissue densities in each paranasal sinus were compared between the ESPAL and EAL groups. RESULTS: All patients in the EAL group had positive CT findings of EA bleeding, compared to only 12.2% in the ESPAL group (P < 0.001). The rate of soft tissue densities within the frontal and sphenoid sinuses were noted in 26.8% and 17.1% of patients in the ESPAL group, compared to 83.3% and 83.3% of patients in the EAL group (P = 0.013 and P = 0.003, respectively). CONCLUSION: PNS CT might be useful for predicting EA bleeding in patients with refractory epistaxis requiring surgical hemostasis.


Asunto(s)
Epistaxis , Seno Esfenoidal , Arterias/diagnóstico por imagen , Arterias/cirugía , Epistaxis/diagnóstico por imagen , Epistaxis/etiología , Humanos , Ligadura , Estudios Retrospectivos , Seno Esfenoidal/diagnóstico por imagen , Seno Esfenoidal/cirugía , Tomografía Computarizada por Rayos X
19.
Molecules ; 25(7)2020 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-32224956

RESUMEN

By simple soaking titanium dioxide (TiO2) films in an aqueous Na2S solution, we could prepare surface-modified photoanodes for application to dye-sensitized solar cells (DSSCs). An improvement in both the open-circuit voltage (Voc) and the fill factor (FF) was observed in the DSSC with the 5 min-soaked photoanode, compared with those of the control cell without any modification. The UV-visible absorbance spectra, UPS valence band spectra, and dark current measurements revealed that the Na2S modification led to the formation of anions on the TiO2 surface, and thereby shifted the conduction band edge of TiO2 in the negative (upward) direction, inducing an increase of 29 mV in the Voc. It was also found that the increased FF value in the surface-treated device was attributed to an elevation in the shunt resistance.


Asunto(s)
Colorantes , Energía Solar , Titanio , Algoritmos , Electricidad , Modelos Teóricos , Análisis Espectral , Sulfuros , Propiedades de Superficie
20.
Langmuir ; 35(42): 13700-13710, 2019 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-31589450

RESUMEN

Compared with hollow microparticles with a completely closed shell structure, hollow polymer microparticles with an open hole on their surface have attracted considerable attention because of the obvious importance of the open hole on their surface; however, the development of a facile method to synthesize such unique open-ended hollow particles has remained a great challenge. In this study, an easy-to-use method was developed to rapidly produce monodispersed hollow and pored microparticles in high reaction yield at room temperature. The key to achieving the unusually shaped polystyrene (PS) microparticles was the use of anisotropic PS seeds. When hollow and dimpled PS seeds prepared using a modified dispersion polymerization method were dispersed in a water-toluene mixture followed by solvent evaporation under ambient conditions, they transformed into hollow PS microparticles with an open hole on their surface. A plausible mechanism for the transformation of the PS microparticles during the swelling and drying processes was proposed on the basis of our results and observations. The structural features of the hollow and pored PS microparticles motivated us to use the particles as a catalyst support. By using modified heterophase polymer dispersion processing involving the addition of a Ag precursor, hollow and pored PS microparticles covered with Ag nanocrystals were obtained on the basis of the in situ reduction of metal precursor on the surface of polymer particles. The resulting Ag nanocrystals/PS hybrid microparticles exhibited enhanced catalytic activity at low concentrations of nanocrystals and could be reused several times without loss of activity when used as catalysts for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA