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1.
J Cell Physiol ; 239(4): e31196, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38240115

RESUMO

The NOD-, LRR-, and Pyrin domain-containing protein 3 (NLRP3) inflammasome plays key roles in regulating inflammation. Numerous studies show that the abnormal activation of NLRP3 associates with the initiation and progression of various diseases. Hence, the NLRP3 inflammasome may be a promising therapeutic target for these diseases. Octyl gallate (OG) is a small molecule with antioxidant, antimicrobial, antifungal, and anti-inflammatory activities; however, the mechanism underlying its anti-inflammatory activity is still unclear. Here, we developed a screening system for NLRP3-inflammasome inhibitors. A total of 3287 small molecules were screened for inhibitors of nigericin-induced NLRP3 oligomerization. OG was identified as a novel inhibitor. We show that OG directly targets the LRR domain of NLRP3 and thereby blocks the inflammatory cascade of the NLRP3 inflammasome. This contrasts with the mode-of-action of other direct NLRP3 inhibitors, which all bind to the NACHT domain of NLRP3. Interestingly, OG also inhibits the priming step by downregulating the Raf-MEK1/2-ERK1/2 axis. Thus, OG inhibits the NLRP3 inflammasome by two distinct mechanisms. Importantly, OG injection ameliorated the inflammation in mouse models of foot gout and sepsis. Our study identifies OG as a potential therapeutic agent for NLRP3-associated diseases.


Assuntos
Anti-Inflamatórios , Ácido Gálico , Inflamassomos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Animais , Camundongos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Ácido Gálico/análogos & derivados , Inflamassomos/efeitos dos fármacos , Inflamação/tratamento farmacológico , Proteína 3 que Contém Domínio de Pirina da Família NLR/química , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Camundongos Endogâmicos C57BL , Masculino , Domínios Proteicos
2.
J Am Chem Soc ; 146(9): 6266-6273, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38394690

RESUMO

Determining the aromaticity of various fluorinated benzenes is challenging as easily obtained experimental aromaticity [Δδ(Houter - Hinner)] necessitates the chemical shifts of inner and outer protons. This issue was addressed in porphyrinoids by replacing the electron-withdrawing (E.W.) groups at the meso-positions of porphyrins and allyliporphyrins. Electronic effects on aromaticity in porphyrinoids have not been thoroughly examined in the literature. In porphyrins, the effect of E.W. groups is minimal, making it difficult to establish a clear relationship between the aromaticity strength and E.W. groups. Conversely, in allyliporphyrins, stronger E.W. groups, such as indandione (IND) derivatives, significantly reduce the aromaticity of the parent structure. The IND derivatives disrupted the aromatic pathway of allyliporphyrin more effectively than those attached to porphyrins. This is attributed to the absence of ß-carbons in allyliporphyrins. The effect of electron-donating (E.D.) groups on porphyrins and allyliporphyrins was further investigated. Contrary to the initial assumption that the E.D. groups might enhance aromaticity owing to their ability to increase electron density, as the strength of the E.D. groups increased, the aromaticity of the porphyrinoids decreased. Despite the modest reduction in aromaticity, any form of electron perturbation reduces aromaticity. The aromaticity of various fluorinated benzenes is expected to parallel our observations of porphyrinoids as representative aromatic polyenes.

3.
Bioorg Med Chem Lett ; 101: 129652, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38346577

RESUMO

Mixed-lineage protein kinase 3 (MLK3) is implicated in several human cancers and neurodegenerative diseases. A series of 3H-imidazo[4,5-b]pyridine derivatives were designed, synthesized and evaluated as novel MLK3 inhibitors. A homology model of MLK3 was developed and all designed compounds were docked to assess their binding pattern and affinity toward the MLK3 active site. Based on this knowledge, we synthesized and experimentally evaluated the designed compounds. Majority of the compounds showed significant inhibition of MLK3 in the enzymatic assay. In particular, compounds 9a, 9e, 9j, 9 k, 12b and 12d exhibited IC50 values of 6, 6, 8, 11, 14 and 14 nM, respectively. Furthermore, compounds 9a, 9e, 9 k and 12b exhibited favorable physicochemical properties among these compounds.


Assuntos
MAP Quinase Quinase Quinase 11 Ativada por Mitógeno , Piridinas , Humanos , Relação Estrutura-Atividade , Piridinas/química , Simulação de Acoplamento Molecular , Inibidores de Proteínas Quinases/química
4.
Eur Spine J ; 33(1): 61-67, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37294358

RESUMO

PURPOSE: The purpose of this study was to investigate autophagy in an extruded disc and to compare this activity with the activity in the remaining disc after lumbar disc herniation in the same patient. METHODS: In total, 12 patients (females 4, males 8) with the extruded type of lumbar disc herniation (LDH) were surgically treated. Their mean age was 54.3 ± 15.8 years (range: 29 ~ 78 years). The mean interval from the occurrence of symptoms to the operation was 9.8 ± 9.4 weeks (range: 2 ~ 24 weeks). The extruded discs were excised, and the remaining disc material removed, to prevent recurrence of herniation. Immediately after specimen collection, all tissues were stored at -70 °C prior to analysis. Autophagy was assessed immunohistochemically and via Western blotting for Atg5, Atg7, Atg12, Atg12L1, and Beclin-1. And the relationship between autophagy and apoptosis was investigated by correlation analysis of caspase-3 with autophagy proteins. RESULTS: The expression levels of autophagic markers were significantly increased in the extruded discs compared to the remaining discs within the same patients. The mean expression levels of Atg5, Atg7, Atg12, and Beclin-1 in extruded discs were statistically significantly higher than those in the remaining discs (P < 0.01, P < 0.001, P < 0.01, and P < 0.001 respectively). CONCLUSIONS: The autophagic pathway was more active in extruded disc material than in remaining disc material within the same patient. This may explain spontaneous resorption of the extruded disc after LDH.


Assuntos
Deslocamento do Disco Intervertebral , Masculino , Feminino , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Deslocamento do Disco Intervertebral/cirurgia , Proteína Beclina-1 , Vértebras Lombares/cirurgia , Discotomia , Autofagia
5.
Knee Surg Sports Traumatol Arthrosc ; 32(4): 1049-1057, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38469925

RESUMO

PURPOSE: This study aimed to compare the 5-year clinical and functional outcomes, including repaired tendon healing status, between early and delayed rehabilitation after arthroscopic rotator cuff repair METHODS: A total of 75 patients with rotator cuff tears (less than 5 cm) underwent arthroscopic repairs over a 60-month period. Participants were randomly assigned to early and delayed postoperative rehabilitation groups with distinct protocols. Clinical and functional outcome measures included Constant score, University of California at Los Angeles (UCLA) score, visual analogue scale for pain and isokinetic dynamometer test for muscle strength recovery. Clinical and functional scores were compared between baseline and 5 years postoperatively. Radiologic assessment via magnetic resonance imaging was performed at a minimum of 12 months postoperatively for evaluations of tendon integrity and recurrent tears. RESULTS: Baseline characteristics showed no statistically significant differences between groups. Both groups demonstrated equivalent improvement in range of motion and pain scores with no statistical differences. Clinical scores improved significantly in both groups by postoperative 12 months and plateaued. At the postoperative 5-year mark, the early group showed better improvement in the visual analogue scale and UCLA score, while the delayed group had superior Constant scores. Postoperative magnetic resonance imaging revealed six recurrent tears, two in the early group and four in the delayed group, with no statistical differences. Muscle strength recovery showed no differences between the two groups. CONCLUSION: Both the early and the delayed rehabilitation groups showed similar outcomes in postoperative range of motion, functional scores, muscle strength recovery and tendon healing in the short- and mid-term follow-ups. LEVEL OF EVIDENCE: Level III.


Assuntos
Procedimentos de Cirurgia Plástica , Lesões do Manguito Rotador , Humanos , Manguito Rotador/cirurgia , Lesões do Manguito Rotador/cirurgia , Tendões/cirurgia , Artroscopia/métodos , Imageamento por Ressonância Magnética , Amplitude de Movimento Articular/fisiologia , Dor/cirurgia , Resultado do Tratamento
6.
Nano Lett ; 23(17): 7897-7905, 2023 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-37435905

RESUMO

A new type of microfluidic bioreactor with fibrous micromixers for the ingredient mixing and a long macrochannel for the in vitro transcription reaction was fabricated for the continuous production of mRNA. The diameter of the fibrous microchannels in the micromixers was tuned by using an electrospun microfibrous disc with different microfiber diameters. The micromixer with a larger diameter of fibrous microchannels exhibited a better mixing performance than the others. The mixing efficiency was increased to 0.95 while the mixture was passed through the micromixers, suggesting complete mixing. To demonstrate the continuous production of mRNA, the ingredients for in vitro transcription were introduced into the perfluoropolyether microfluidic bioreactor. The mRNA synthesized by the microfluidic bioreactor had the same sequence and in vitro/in vivo performances as those prepared by the bulk reaction. The continuous reaction in the microfluidic bioreactor with efficient mixing performance can be used as a powerful platform for various microfluidic reactions.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Desenho de Equipamento
7.
BMC Musculoskelet Disord ; 24(1): 936, 2023 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-38042790

RESUMO

BACKGROUND: We have applied primarily multiple locking compression miniplates in treating multifragmentary, comminuted patellar fracture in combination with conventional fixation methods. METHODS: Medical and radiologic data were retrospectively reviewed for the patients surgically fixated with locking compression miniplates in patellar fracture of AO/OTA 34-C3. The primary outcome was bone union at the final follow-up, and the secondary outcomes were functional outcomes and postoperative complications associated with the procedure. For the functional assessment, the Lysholm score, Tegner scores, and the knee range of motion was compared. RESULTS: A total of twenty patients with AO/OTA 34-C3 patellar fracture were included in the study with an average follow-up period of 15 months (range:11 ~ 18 months) between June 2018 and November 2021. Eleven male and nine female patients presented an average age of 57.15 years. The primary fracture union was seen in all twenty patients, and the average time to the union was 15.6 weeks on serial radiograph follow-up. All patients did not show any postoperative complications, such as fixation failure, infection, or revision operations. Postoperatively, all patients achieved an average range of motion of 130 degrees, and the Lysholm and Tegners scores showed an average of 90.4 and 5.0 at the final follow-up, retrospectively. CONCLUSION: Fixations with miniplates in comminuted patellar fractures can be a useful option for effective osteosynthesis due to their versatile, efficient, and low-profile nature.


Assuntos
Fraturas Ósseas , Fraturas Cominutivas , Traumatismos do Joelho , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Patela/diagnóstico por imagem , Patela/cirurgia , Fraturas Ósseas/cirurgia , Fixação Interna de Fraturas/métodos , Fraturas Cominutivas/diagnóstico por imagem , Fraturas Cominutivas/cirurgia , Traumatismos do Joelho/diagnóstico por imagem , Traumatismos do Joelho/cirurgia , Complicações Pós-Operatórias
8.
Proc Natl Acad Sci U S A ; 117(6): 3135-3143, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31980519

RESUMO

The objective of this study was to examine FoxO expression and FoxO function in meniscus. In menisci from human knee joints with osteoarthritis (OA), FoxO1 and 3 expression were significantly reduced compared with normal menisci from young and old normal donors. The expression of FoxO1 and 3 was also significantly reduced in mouse menisci during aging and OA induced by surgical meniscus destabilization or mechanical overuse. Deletion of FoxO1 and combined FoxO1, 3, and 4 deletions induced abnormal postnatal meniscus development in mice and these mutant mice spontaneously displayed meniscus pathology at 6 mo. Mice with Col2Cre-mediated deletion of FoxO3 or FoxO4 had normal meniscus development but had more severe aging-related damage. In mature AcanCreERT2 mice, the deletion of FoxO1, 3, and 4 aggravated meniscus lesions in all experimental OA models. FoxO deletion suppressed autophagy and antioxidant defense genes and altered several meniscus-specific genes. Expression of these genes was modulated by adenoviral FoxO1 in cultured human meniscus cells. These results suggest that FoxO1 plays a key role in meniscus development and maturation, and both FoxO1 and 3 support homeostasis and protect against meniscus damage in response to mechanical overuse and during aging and OA.


Assuntos
Proteína Forkhead Box O1 , Proteína Forkhead Box O3 , Articulação do Joelho/metabolismo , Menisco/metabolismo , Osteoartrite/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Modelos Animais de Doenças , Feminino , Proteína Forkhead Box O1/análise , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Proteína Forkhead Box O3/análise , Proteína Forkhead Box O3/genética , Proteína Forkhead Box O3/metabolismo , Humanos , Masculino , Menisco/crescimento & desenvolvimento , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Adulto Jovem
9.
Development ; 146(5)2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30745431

RESUMO

C. elegans heterochronic genes determine the timing of expression of specific cell fates in particular stages of developing larvae. However, their broader roles in coordinating developmental events across diverse tissues have been less well investigated. Here, we show that loss of lin-28, a central heterochronic regulator of hypodermal development, causes reduced fertility associated with abnormal somatic gonadal morphology. In particular, the abnormal spermatheca-uterine valve morphology of lin-28(lf) hermaphrodites traps embryos in the spermatheca, which disrupts ovulation and causes embryonic lethality. The same genes that act downstream of lin-28 in the regulation of hypodermal developmental timing also act downstream of lin-28 in somatic gonadal morphogenesis and fertility. Importantly, we find that hypodermal expression, but not somatic gonadal expression, of lin-28 is sufficient for restoring normal somatic gonadal morphology in lin-28(lf) mutants. We propose that the abnormal somatic gonadal morphogenesis of lin-28(lf) hermaphrodites results from temporal discoordination between the accelerated hypodermal development and normally timed somatic gonadal development. Thus, our findings exemplify how a cell-intrinsic developmental timing program can also control proper development of other interacting tissues, presumably by cell non-autonomous signal(s). This article has an associated 'The people behind the papers' interview.


Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/fisiologia , Gônadas/fisiologia , Morfogênese , Proteínas Repressoras/fisiologia , Animais , Animais Geneticamente Modificados , Diferenciação Celular , Movimento Celular , Feminino , Fertilização , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fluorescência Verde/fisiologia , Masculino , Mutação , Ovulação , Plasmídeos , Interferência de RNA , Proteínas de Ligação a RNA/fisiologia
10.
Bioorg Med Chem ; 53: 116550, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34890995

RESUMO

Under certain conditions, numerous soluble proteins possess an inherent tendency to convert into insoluble amyloid aggregates, which are associated with several sporadic and genetic human diseases. Transthyretin (TTR) is one of the more than 30 human amyloidogenic proteins involved in conditions such as senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. Considerable effort has been focused on identifying the native tetrameric TTR stabilizers to inhibit rate-limiting tetramer dissociation and, consequently, ameliorate TTR amyloidogenesis. Here, we describe the design and synthesis of quinolin-2(1H)-one derivatives that could be structurally complementary to the thyroxine-binding site within tetrameric TTR. Among these quinolin-2(1H)-one derivatives, compound 7a allowed 16.7% of V30M-TTR (3.6 µM) fibril formation at the same concentration and 49.6% at a concentration of 1.8 µM. Compound 7a exhibited much greater potency in complex biological samples like human plasma than that observed with tafamidis, the drug approved for the treatment of TTR amyloid cardiomyopathy for wild-type or hereditary TTR-mediated amyloidosis. Furthermore, the unique spectral properties of compound 7a demonstrated its high potential for TTR quantification, imaging sensors, and fluorescent tools to study the mechanism of TTR amyloidogenesis.


Assuntos
Neuropatias Amiloides Familiares/metabolismo , Fluorescência , Quinolonas/farmacologia , Animais , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Quinolonas/química , Quinolonas/metabolismo , Ratos , Espectrometria de Fluorescência , Relação Estrutura-Atividade
11.
Macromol Rapid Commun ; 43(21): e2200423, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36056922

RESUMO

CO2 -triggered in situ hydrogels is developed from waterborne poly(ε-caprolactone)-based polyurethane (PU) dispersion and aqueous polyethyleneimine (PEI) solution without any other chemicals and apparatus (e.g., UV light). In the approach, nontoxic CO2 in air is used as a selective trigger for the hydrogel formation. CO2 adsorption onto PEI results in the formation of ammonium cations in PEI and the subsequent multiple ionic crosslinking between PU and PEI chains. Besides the amount of CO2 in air, the rate of hydrogel formation can be controlled by NaHCO3 in the PU-PEI mixture, which serves as a CO2 supplier. The PU hydrogels exhibit tough and stretchable properties with high tensile strength (2.05 MPa) and elongation at break (438.24%), as well as biocompatibility and biodegradability. In addition, the PU hydrogels exhibit high adhesion strength on skin and injectability due to the in situ formation. It is believed that these PU hydrogels have the ideal features for various future applications, such as tissue adhesion barriers, wound dressing, artificial skin, and injectable fillers.


Assuntos
Hidrogéis , Poliuretanos , Hidrogéis/química , Poliuretanos/química , Polietilenoimina/química , Dióxido de Carbono , Resistência à Tração
12.
Nano Lett ; 21(20): 8554-8562, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34623164

RESUMO

As a 3D topological insulator, bismuth selenide (Bi2Se3) has potential applications for electrically and optically controllable magnetic and optoelectronic devices. Understanding the coupling with its topological phase requires studying the interactions of carriers with the lattice on time scales down to the subpicosecond regime. Here, we investigate the ultrafast carrier-induced lattice contractions and interlayer modulations in Bi2Se3 thin films by time-resolved diffraction using an X-ray free-electron laser. The lattice contraction depends on the carrier concentration and is followed by an interlayer expansion accompanied by oscillations. Using density functional theory and the Lifshitz model, the initial contraction can be explained by van der Waals force modulation of the confined free carrier layers. Our theoretical calculations suggest that the band inversion, related to a topological phase transition, is modulated by the expansion of the interlayer distance. These results provide insights into the topological phase control by light-induced structural change on ultrafast time scales.

13.
Nano Lett ; 20(12): 8541-8548, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33174748

RESUMO

Fundamental understanding of structural changes during catalytic reactions is crucial to understanding the underlying mechanisms and optimizing efficiencies. Surface energy and related catalytic mechanisms are widely studied. However, the catalyst lattice deformation induced by catalytic processes is not well understood. Here, we study the strain in an individual platinum (Pt) nanoparticle (NP) using Bragg coherent diffraction imaging under in situ oxidation and reduction reactions. When Pt NPs are exposed to H2O2, a typical oxidizer and an intermediate during the oxygen reduction reaction process, alternating overall strain distribution near the surface and inside the NP is observed at the (111) Bragg reflection. In contrast, relatively insignificant changes appear in the (200) reflection. Density functional theory calculations are employed to rationalize the anisotropic lattice strain in terms of induced stress by H2O2 adsorption and decomposition on the Pt NP surface. Our study provides deeper insight into the activity-structure relationship in this system.

14.
Sensors (Basel) ; 20(5)2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32143335

RESUMO

The food industry requires rapid and simple detection methods for preventing harm from pathogenic bacteria. Until now, various technologies used to detect foodborne bacteria were time-consuming and laborious. Therefore, we have developed an automated immunomagnetic separation combined with a colorimetric assay for the rapid detection of E. coli O157:H7 in food samples. The colorimetric detection method using enzymatic reaction is fascinating because of its simplicity and rapidity and does not need sophisticated devices. Moreover, the proposed procedures for the detection of bacteria in food take less than 3 h including pre-enrichment, separation and detection steps. First, target-specific immunomagnetic beads were introduced to contaminated milk in a pre-enrichment step. Second, the pre-enriched sample solution containing target bacteria bound on immunomagnetic beads was injected into an automated pretreatment system. Subsequently, the immunomagnetic beads along with target bacteria were separated and concentrated into a recovery tube. Finally, released ß-galactosidase from E. coli O157:H7 after lysis was reacted with chlorophenol red ß-galactopyranoside (CPRG) used as a substrate and the colorimetric change of CPRG was determined by absorbance measuring or the naked eye. By the proposed approach in this study, we could detect 3 × 102 CFU/mL of E. coli O157:H7 from a milk sample within 3 h.


Assuntos
Colorimetria/métodos , Ensaios Enzimáticos , Escherichia coli O157/isolamento & purificação , Separação Imunomagnética/métodos , beta-Galactosidase/metabolismo , Animais , Automação , Escherichia coli O157/ultraestrutura , Leite/microbiologia
15.
J Nanosci Nanotechnol ; 19(3): 1403-1409, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469196

RESUMO

In this paper, we propose a high sensitivity polarimetric optical fiber pressure sensor (OFPS) using a polarization-diversity loop composed of a polarization beam splitter, polarization controllers, and a sensor head. The sensor head consists of 8-cm-long tapered panda-type polarization-maintaining fiber (PMF) and a fiber Bragg grating (FBG) directly spliced with PMF, and the sensor head is located inside a pressure chamber. A pressure-induced birefringence change due to the photoelastic effect can be greatly enhanced at the tapered section of PMF, thereby increasing the pressure sensitivity of the sensor head. The tapered PMF was fabricated using a fusion splicer, and the tapered length and center waist diameter of the tapered PMF segment were ~350 and ~56.82 µm, respectively. At the polarization-diversity loop, PMF is used as a birefringent element to create an interference spectrum due to polarization interference. A pressure-induced birefringence change of PMF results in a wavelength shift of the interference spectrum. Because the PMF birefringence also has a cross sensitivity to temperature, the FBG is utilized for the compensation of the temperature effect on it. The resonance wavelength of the FBG is sensitive to ambient temperature changes but insensitive to changes in pressure. This spectral response of the FBG can be used to compensate additional ambient temperature changes occurred at the sensor head. The pressure sensitivity of our sensor was measured as approximately -27.70 nm/MPa, and an adjusted R² value representing the sensor linearity was measured as ~0.9903 in a measurement range of 0-0.5 MPa. Our fabricated sensor exhibits the highest pressure sensitivity among previously reported polarimetric OFPS.

16.
J Nanosci Nanotechnol ; 19(3): 1500-1505, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469213

RESUMO

In this paper, we investigated the pressure and temperature dependence of the frequency and amplitude of the field-induced oscillation created in a two-terminal device based on a vanadium dioxide (VO2) thin film. First, a simple oscillation circuit was constructed using a VO2-based two-terminal device, a standard resistor, and a DC power supply. Then, the frequency and amplitude variation of the field-induced oscillation was observed for pressure changes applied to the VO2 device in a pressure chamber. This variation of the oscillation characteristics was also examined for ambient temperature changes applied to the VO2 device using a plate heater. When the chamber pressure increased from 0 to 5 MPa with a step of 1 MPa at 25 °C, the oscillation frequency increased from ~592 to ~739 kHz, and the oscillation amplitude decreased from ~12.60 to ~11.40 V. Similarly, when the heater temperature increased from 25 to 50 °C (step: 5 °C) without applied pressure, the oscillation frequency increased from ~592 to ~819 kHz, and the oscillation amplitude decreased from ~12.60 to ~7.16 V. Owing to linear pressure and temperature responses of the VO2 oscillation, the pressure and temperature sensitivities of the oscillation frequency and amplitude could be obtained as four different constant coefficients from the measurement results. These coefficients can be directly utilized for simultaneously measuring pressure and temperature variation applied to the VO2 device, which can be beneficially applied to localized temperature and pressure sensing at a very small area less than 1 mm².

17.
J Nanosci Nanotechnol ; 19(3): 1543-1548, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469220

RESUMO

Here we show 60 mA bidirectional current gating in a two-terminal planar device based on a highly resistive vanadium dioxide (VO2) thin film by harnessing photothermally induced phase transition occurred in VO2 when irradiating the VO2 film with a CO2 laser oscillating at 10.6 µm. The VO2 thin film was grown by a pulsed laser deposition method, and the two-terminal planar device was fabricated using the VO2 film isolated with sub-millimeter dimensions. The bidirectional current gating between 0 and 60 mA was accomplished by irradiating the VO2-based device with repetitive pulses of the CO2 laser. In terms of laser modulation parameters such as the pulse width and repetition rate, their effect on the transient responses of laser-gated currents was also investigated. With a minimum energy per pulse of ~766 mJ, a stable bidirectional current gating of up to 60 mA could be successfully implemented for the repetition rates of 0.5-3.0 Hz in a VO2 device biased at ~5.4 V, showing a switching contrast between off- and on-state currents of ~11089. This maximum onstate current (60 mA) and switching contrast are the highest values among previous gating results attained in VO2 devices with a CO2 laser.

18.
J Nanosci Nanotechnol ; 19(3): 1603-1608, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469230

RESUMO

By incorporating an inline switching filter, which is comprised of a polarization-diversified loop (PDL), two fiber Bragg gratings (FBGs) with different resonances, and three quarter-wave plates (QWPs), we propose a dual-wavelength-switchable erbium-doped fiber (EDF) ring laser that can select and switch between two lasing lines with orthogonal polarization. The proposed laser is composed of EDF, a 980 nm laser diode, a wavelength-division-multiplexing coupler, a rotatable linear polarizer, an optical isolator, a 3 dB optical coupler, and the inline switching filter. At a special combination of the orientation angles of the three QWPs, the inline filter can offer a different transmittance according to input polarization, e.g., reflection spectra of one and the other of the two FBGs for linear horizontally and vertically polarized input light, respectively. At this special combination of the QWPs, one of two different resonances of the two FBGs can be selected by varying laser cavity polarization through the adjustment of the orientation angle of the rotatable linear polarizer. Consequently, switching operation between two laser lines with orthogonal polarization at the two FBG resonance wavelengths could be obtained by properly controlling cavity polarization. The polarization extinction ratio of each lasing line was measured as more than 19.9 dB.

19.
J Nanosci Nanotechnol ; 19(3): 1620-1625, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469233

RESUMO

By incorporating a high-power 976 nm laser diode (LD), we demonstrated laser-regulated current switching in a two-terminal planar device based on a vanadium dioxide (VO2) thin film. The VO2 thin film was grown by pulsed laser deposition method and etched to sub-millimeter dimension for the fabrication of a two-terminal device. The reversible current switching was implemented by controlling the on/off state of the LD, which illuminates the VO2-based device. The transient responses of the device currents were analyzed when the device was excited with laser pulses of various repetition rates of up to 5.0 Hz with a pulse width fixed as 75 ms. A switching contrast between off- and on-state currents was calculated as ~9530, and average rising and falling times were measured as ~31 and ~21 ms, respectively.

20.
Int Orthop ; 43(9): 2117-2124, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30318561

RESUMO

INTRODUCTION: To determine whether the placement of an interscalene brachial plexus block (IBPB) with general anaesthesia before shoulder arthroscopy would be effective in establishing a clear visual field and in shortening the surgical procedure. METHOD: This prospective randomized control trial study included 152 patients who had undergone arthroscopic rotator cuff repair. Group A received IBPB and group B did not receive IBPB. A visual clarity scale (VCS) was determined by arthroscopic visualization. The systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), duration of surgical procedure, VCS, and medication that was administered for haemodynamic stability were recorded. RESULTS: The VCS was improved in group A at stages 2 and 3 of the surgical procedures (p < 0.05), but there were no significant difference at stages 1 (p = 0.288) and 4 (p = 0.062). SBP, DBP, and HR were higher in group B during surgery (p < 0.05). The administered analgesics were higher in group B (p = 0.003), but there were no differences in hypotensive agents (p = 0.287). No significant difference was observed for the duration of surgery (p = 0.704). CONCLUSIONS: Pre-operative IBPB with general anaesthesia for arthroscopic rotator cuff repair was beneficial in maintaining haemodynamic stability and improving the VCS during surgery.


Assuntos
Analgésicos/administração & dosagem , Artroscopia/métodos , Bloqueio do Plexo Braquial/métodos , Lesões do Manguito Rotador/cirurgia , Idoso , Anestesia Geral , Feminino , Hemodinâmica , Humanos , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Estudos Prospectivos
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