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1.
PLoS Biol ; 21(8): e3002281, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37643163

RESUMEN

The central circadian clock of the suprachiasmatic nucleus (SCN) is a network consisting of various types of neurons and glial cells. Individual cells have the autonomous molecular machinery of a cellular clock, but their intrinsic periods vary considerably. Here, we show that arginine vasopressin (AVP) neurons set the ensemble period of the SCN network in vivo to control the circadian behavior rhythm. Artificial lengthening of cellular periods by deleting casein kinase 1 delta (CK1δ) in the whole SCN lengthened the free-running period of behavior rhythm to an extent similar to CK1δ deletion specific to AVP neurons. However, in SCN slices, PER2::LUC reporter rhythms of these mice only partially and transiently recapitulated the period lengthening, showing a dissociation between the SCN shell and core with a period instability in the shell. In contrast, in vivo calcium rhythms of both AVP and vasoactive intestinal peptide (VIP) neurons in the SCN of freely moving mice demonstrated stably lengthened periods similar to the behavioral rhythm upon AVP neuron-specific CK1δ deletion, without changing the phase relationships between each other. Furthermore, optogenetic activation of AVP neurons acutely induced calcium increase in VIP neurons in vivo. These results indicate that AVP neurons regulate other SCN neurons, such as VIP neurons, in vivo and thus act as a primary determinant of the SCN ensemble period.


Asunto(s)
Arginina Vasopresina , Calcio , Animales , Ratones , Neuronas , Núcleo Supraquiasmático , Neuroglía , Péptido Intestinal Vasoactivo
2.
J Neurosci ; 44(8)2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38238074

RESUMEN

The suprachiasmatic nucleus (SCN) is the central clock for circadian rhythms. Animal studies have revealed daily rhythms in the neuronal activity in the SCN. However, the circadian activity of the human SCN has remained elusive. In this study, to reveal the diurnal variation of the SCN activity in humans, we localized the SCN by employing an areal boundary mapping technique to resting-state functional images and investigated the SCN activity using perfusion imaging. In the first experiment (n = 27, including both sexes), we scanned each participant four times a day, every 6 h. Higher activity was observed at noon, while lower activity was recorded in the early morning. In the second experiment (n = 20, including both sexes), the SCN activity was measured every 30 min for 6 h from midnight to dawn. The results showed that the SCN activity gradually decreased and was not associated with the electroencephalography. Furthermore, the SCN activity was compatible with the rodent SCN activity after switching off the lights. These results suggest that the diurnal variation of the human SCN follows the zeitgeber cycles of nocturnal and diurnal mammals and is modulated by physical lights rather than the local time.


Asunto(s)
Ritmo Circadiano , Núcleo Supraquiasmático , Masculino , Animales , Femenino , Humanos , Ritmo Circadiano/fisiología , Núcleo Supraquiasmático/fisiología , Roedores , Mamíferos , Neuronas
3.
Am J Gastroenterol ; 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38864517

RESUMEN

INTRODUCTION: There is considerable concern about whether endoscopic resection (ER) prior to additional surgery (AS) for T1 colorectal cancer (CRC) has oncologically potential adverse effects. Therefore, this study aimed to compare the long-term outcomes, including overall survival (OS), of patients treated with AS after ER versus primary surgery (PS) for T1 CRC using a propensity score-matched analysis from a large observational study. METHODS: This study investigated 6105 patients with T1 CRC treated with either ER or surgical resection between 2009 and 2016 at 27 high-volume Japanese institutions, with those undergoing surgery alone included in the PS group and those undergoing AS after ER included in the AS group. Propensity score matching was used for long-term outcomes of mortality and recurrence analysis. RESULTS: After propensity score matching, 1219 of 2438 patients were identified in each group. The 5-year OS rates in the AS and PS groups were 97.1% and 96.0%, respectively (hazard ratio: 0.72, 95% confidence interval [CI]: 0.49-1.08), indicating the non-inferiority of the AS group. Moreover, 32 patients (2.6%) in the AS group and 24 (2.0%) in the PS group had recurrences, with no significant difference between the two groups (odds ratio: 1.34, 95% CI: 0.76-2.40, p = 0.344). DISCUSSION: ER prior to AS for T1 CRC had no adverse effect on patients' long-term outcomes, including the 5-year OS rate. ER is a viable first-line treatment option for endoscopically resectable T1 CRC.

4.
Opt Express ; 32(3): 4295-4304, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38297633

RESUMEN

We demonstrate a hybrid integrated laser by transfer printing an InAs/GaAs quantum dot (QD) amplifier on a Si waveguide with distributed Bragg reflectors (DBRs). The QD waveguide amplifier of 1.6 mm long was patterned in the form of an airbridge with the help of a spin-on-glass sacrificial layer and precisely integrated on the silicon-on-insulator (SOI) waveguide by pick-and-place assembly using an elastomer stamp. Laser oscillation was observed around the wavelength of 1250 nm with a threshold current of 47 mA at room temperature and stable operation up to 80°C. Transfer printing of the long QD amplifiers will enable the development of various hybrid integrated laser devices that leverage superior properties of QDs as laser gain medium.

5.
Phys Chem Chem Phys ; 26(21): 15115-15119, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38592673

RESUMEN

In situ 3D computed tomography imaging with statistical analysis successfully revealed the water accumulation and drainage characteristics in the stacked gas diffusion layers (GDLs) and membrane electrode assembly (MEA) of a polymer electrolyte fuel cell. Efficient water drainage at the interface between the cathode GDL and MEA was confirmed upon supplying oxygen to the cathode.

6.
Proc Natl Acad Sci U S A ; 118(6)2021 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-33526663

RESUMEN

The suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals, is a network structure composed of multiple types of γ-aminobutyric acid (GABA)-ergic neurons and glial cells. However, the roles of GABA-mediated signaling in the SCN network remain controversial. Here, we report noticeable impairment of the circadian rhythm in mice with a specific deletion of the vesicular GABA transporter in arginine vasopressin (AVP)-producing neurons. These mice showed disturbed diurnal rhythms of GABAA receptor-mediated synaptic transmission in SCN neurons and marked lengthening of the activity time in circadian behavioral rhythms due to the extended interval between morning and evening locomotor activities. Synchrony of molecular circadian oscillations among SCN neurons did not significantly change, whereas the phase relationships between SCN molecular clocks and circadian morning/evening locomotor activities were altered significantly, as revealed by PER2::LUC imaging of SCN explants and in vivo recording of intracellular Ca2+ in SCN AVP neurons. In contrast, daily neuronal activity in SCN neurons in vivo clearly showed a bimodal pattern that correlated with dissociated morning/evening locomotor activities. Therefore, GABAergic transmission from AVP neurons regulates the timing of SCN neuronal firing to temporally restrict circadian behavior to appropriate time windows in SCN molecular clocks.


Asunto(s)
Relojes Circadianos , Ritmo Circadiano , Neuronas/metabolismo , Núcleo Supraquiasmático/metabolismo , Vasopresinas/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Animales , Conducta Animal , Calcio/metabolismo , Relojes Circadianos/genética , Ritmo Circadiano/genética , Regulación de la Expresión Génica , Locomoción , Ratones , Sinapsis/fisiología , Transmisión Sináptica/fisiología , Factores de Tiempo , Proteínas del Transporte Vesicular de Aminoácidos Inhibidores/deficiencia , Proteínas del Transporte Vesicular de Aminoácidos Inhibidores/metabolismo
7.
Am J Kidney Dis ; 81(2): 134-144.e1, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35810827

RESUMEN

RATIONALE & OBJECTIVE: Treatment of asymptomatic hyperuricemia is not commonly implemented. However, it is unclear whether urate deposition that begins during asymptomatic hyperuricemia can induce nephropathy. Dysfunction of ATP-binding cassette subfamily G member 2 (ABCG2), a urate efflux transporter, leads to elevated serum uric acid concentration (SUA). We investigated the association between asymptomatic hyperuricemia and decreased estimated glomerular filtration rate (eGFR), and the impact of ABCG2 on this relationship. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 1,885 Japanese adults undergoing routine health care follow-up between 2007 and 2017 who had eGFR ≥60 mL/min/1.73 m2, of which 311 had asymptomatic hyperuricemia (SUA >7.0 mg/dL). Study participants were classified into 3 categories of estimated ABCG2 function (full, 75%, and ≤50% function). PREDICTORS: Baseline SUA and estimated ABCG2 function. OUTCOME: Change in eGFR over time. ANALYTICAL APPROACH: Linear mixed-effect models were used to analyze the relationship between asymptomatic hyperuricemia, ABCG2 function, and eGFR decline. RESULTS: Asymptomatic hyperuricemia was negligibly associated with eGFR decline overall. However, among those with eGFR 60-89 mL/min/1.73 m2 and ≤50% ABCG2 function, eGFR decline was associated with asymptomatic hyperuricemia (P = 0.03). ABCG2 was not associated with eGFR reductions when the SUA was <6.0 mg/dL. Among participants with SUA ≥6.0 mg/dL and eGFR 60-89 mL/min/1.73 m2, ≤50% ABCG2 function was associated with approximately 1.2-fold faster eGFR decline compared with fully functional ABCG2 (P = 0.02). Among the participants with SUA ≥6.0 mg/dL and eGFR 60-89 mL/min/1.73 m2, the adjusted eGFR slopes (given as mean ± standard error of the mean, in mL/min/1.73 m2 per year) were -0.946 ± 0.049, -1.040 ± 0.046, and -1.148 ± 0.069 for full, 75%, and ≤50% ABCG2 function, respectively. LIMITATIONS: Lack of measurement of urinary urate and uremic toxins that are known to be transported by ABCG2, and no independent validation cohort. CONCLUSIONS: Asymptomatic hyperuricemia was not associated with eGFR decline, except when in the presence of ≤50% ABCG2 function. PLAIN-LANGUAGE SUMMARY: The urate transporter ABCG2 is a protein that regulates serum urate concentrations; when dysfunctional, it can lead to elevated serum concentrations of this compound (ie, hyperuricemia). Although persistent hyperuricemia induces gout and kidney injury, the effects on organs during the asymptomatic phase have yet to be established. Therefore, to clarify the relationship between ABCG2, asymptomatic hyperuricemia, and kidney function, we conducted a retrospective cohort study of 1,885 healthy participants, including 311 participants with asymptomatic hyperuricemia. We found that the coexistence of asymptomatic hyperuricemia and severe ABCG2 dysfunction was associated with the age-dependent decline in kidney function. We concluded that asymptomatic hyperuricemia represents a risk factor for chronic kidney disease, at least in individuals with highly dysfunctional ABCG2. This new finding highlights the potential importance of ABCG2 in the pathogenesis of hyperuricemia-induced kidney injury.


Asunto(s)
Hiperuricemia , Insuficiencia Renal Crónica , Adulto , Humanos , Ácido Úrico , Estudios Retrospectivos , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Proteínas de Neoplasias
8.
Opt Lett ; 48(23): 6344-6347, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38039263

RESUMEN

We generated gain-switched pulses via electrical pulse excitations in a 1270 nm distributed feedback (DFB) laser diode (LD) with a direct-modulation bandwidth of 30 GHz. The measurements revealed short-pulse widths of 5.3 and 8.8 ps with and without chirp compensation, via a single-mode optical fiber. The 5.3 ps pulses exhibited a spectral width of 0.40 nm (spectral bandwidth of 71 GHz), yielding a time-bandwidth product of 0.38. Although the gain-switched pulses in DFB LDs inherently contain linear and nonlinear chirp, optimized pumping conditions enable generation of nearly transform-limited ps pulses after linear chirp compensation.

9.
Gastrointest Endosc ; 97(6): 1119-1128.e5, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36669574

RESUMEN

BACKGROUND AND AIMS: Since 2009, the Japanese Society for Cancer of the Colon and Rectum guidelines have recommended that tumor budding and submucosal invasion depth, in addition to lymphovascular invasion and tumor grade, be included as risk factors for lymph node metastasis (LNM) in patients with T1 colorectal cancer (CRC). In this study, a novel nomogram was developed and validated by usirge-scale, real-world data, including the Japanese Society for Cancer of the Colon and Rectum risk factors, to accurately evaluate the risk of LNM in T1 CRC. METHODS: Data from 4673 patients with T1 CRC treated at 27 high-volume institutions between 2009 and 2016 were analyzed for LNM risk. To prepare a nonrandom split sample, the total cohort was divided into development and validation cohorts. Pathologic findings were extracted from the medical records of each participating institution. The discrimination ability was measured by using the concordance index, and the variability in each prediction was evaluated by using calibration curves. RESULTS: Six independent risk factors for LNM, including submucosal invasion depth and tumor budding, were identified in the development cohort and entered into a nomogram. The concordance index was .784 for the clinical calculator in the development cohort and .790 in the validation cohort. The calibration curve approached the 45-degree diagonal in the validation cohort. CONCLUSIONS: This is the first nomogram to include submucosal invasion depth and tumor budding for use in routine pathologic diagnosis based on data from a nationwide multi-institutional study. This nomogram, developed with real-world data, should improve decision-making for an appropriate treatment strategy for T1 CRC.


Asunto(s)
Neoplasias del Colon , Neoplasias Colorrectales , Humanos , Nomogramas , Metástasis Linfática , Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/patología , Invasividad Neoplásica/patología
10.
Clin Gastroenterol Hepatol ; 20(10): 2327-2336.e4, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-34968729

RESUMEN

BACKGROUND & AIMS: Postoperative Crohn's disease (CD) surveillance relies on endoscopic monitoring. The role of cross-sectional imaging is less clear. We evaluated the concordance of cross-sectional enterography with endoscopic recurrence and the predictive ability of radiography for future CD postoperative recurrence. METHODS: We performed a multi-institution retrospective cohort study of postoperative adult patients with CD who underwent ileocolonoscopy and cross-sectional enterography within 90 days of each other following ileocecal resection. Imaging studies were interpreted by blinded, expert CD radiologists. Patients were categorized by presence of endoscopic postoperative recurrence (E+) (modified Rutgeerts' score ≥i2b) or radiographic disease activity (R+) and grouped by concordance status. RESULTS: A total of 216 patients with CD with paired ileocolonoscopy and imaging were included. A majority (54.2%) exhibited concordance (34.7% E+/R+; 19.4% E-/R-) between studies. The plurality (41.7%; n = 90) were E-/R+ discordant. Imaging was highly sensitive (89.3%), with low specificity (31.8%), in detecting endoscopic postoperative recurrence. Intestinal wall thickening, luminal narrowing, mural hyper-enhancement, and length of disease on imaging were associated with endoscopic recurrence (all P < .01). Radiographic disease severity was associated with increasing Rutgeerts' score (P < .001). E-/R+ patients experienced more rapid subsequent endoscopic recurrence (hazard ratio, 4.16; P = .033) and increased rates of subsequent endoscopic (43.8% vs 22.7%) and surgical recurrence (20% vs 9.5%) than E-/R- patients (median follow-up, 4.5 years). CONCLUSIONS: Cross-sectional imaging is highly sensitive, but poorly specific, in detecting endoscopic disease activity and postoperative recurrence. Advanced radiographic disease correlates with endoscopic severity. Patients with radiographic activity in the absence of endoscopic recurrence may be at increased risk for future recurrence, and closer monitoring should be considered.


Asunto(s)
Enfermedad de Crohn , Adulto , Colon/cirugía , Colonoscopía/métodos , Enfermedad de Crohn/diagnóstico por imagen , Enfermedad de Crohn/cirugía , Humanos , Íleon/cirugía , Recurrencia , Estudios Retrospectivos
11.
Biochem Biophys Res Commun ; 632: 181-188, 2022 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-36215905

RESUMEN

The number of patients with heart failure and related deaths is rapidly increasing worldwide, making it a major problem. Cardiac hypertrophy is a crucial preliminary step in heart failure, but its treatment has not yet been fully successful. In this study, we established a system to evaluate cardiomyocyte hypertrophy using a deep learning-based high-throughput screening system and identified drugs that inhibit it. First, primary cultured cardiomyocytes from neonatal rats were stimulated by both angiotensin II and endothelin-1, and cellular images were captured using a phase-contrast microscope. Subsequently, we used a deep learning model for instance segmentation and established a system to automatically and unbiasedly evaluate the cardiomyocyte size and perimeter. Using this system, we screened 100 FDA-approved drugs library and identified 12 drugs that inhibited cardiomyocyte hypertrophy. We focused on ezetimibe, a cholesterol absorption inhibitor, that inhibited cardiomyocyte hypertrophy in a dose-dependent manner in vitro. Additionally, ezetimibe improved the cardiac dysfunction induced by pressure overload in mice. These results suggest that the deep learning-based system is useful for the evaluation of cardiomyocyte hypertrophy and drug screening, leading to the development of new treatments for heart failure.


Asunto(s)
Cardiomegalia , Aprendizaje Profundo , Evaluación Preclínica de Medicamentos , Insuficiencia Cardíaca , Animales , Ratones , Ratas , Angiotensina II/farmacología , Cardiomegalia/diagnóstico por imagen , Cardiomegalia/tratamiento farmacológico , Células Cultivadas , Colesterol , Evaluación Preclínica de Medicamentos/métodos , Endotelina-1 , Ezetimiba , Insuficiencia Cardíaca/tratamiento farmacológico , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos
12.
Aging Male ; 25(1): 228-233, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35997228

RESUMEN

Osteoporosis is often accompanied by bone loss with fat accumulation of the red marrow. A novel technique for quantification of iron and fat content by MRI IDEAL-IQ can visualize hematopoietic areas and fatty deposits in bone marrow; however, the relationship between these indices and total hip bone mineral density (BMD) remains unclear. In this study, the proximal femur of 104 men who underwent pelvic MRI and bone densitometry prior to treatment for non-metastatic prostate cancer was retrospectively examined to investigate the R2* value to quantify iron and proton density fat fraction (PDFF) to assess bone marrow fat content. R2* was significantly positively correlated with BMD (r = 0.6017, p < 0.0001), and PDFF was not correlated with BMD (r = -0.1302, p = 0.0512). Patients with BMD T-score ≤ -2.5 had significantly lower R2* than patients with BMD T-score > -2.5; however, there was no significant difference in PDFF. In the ROC analysis, which examined the predictive ability of R2* with BMD T-score ≤ -2.5 as an outcome, the cut-off value of R2* was 50.7 s-1 (AUC 0.817). These results show R2* correlated with BMD. R2* may be a non-invasive surrogate marker for diagnosing male osteoporosis.


Asunto(s)
Osteoporosis , Neoplasias de la Próstata , Absorciometría de Fotón , Densidad Ósea , Estudios de Factibilidad , Fémur/diagnóstico por imagen , Humanos , Hierro , Imagen por Resonancia Magnética/métodos , Masculino , Osteoporosis/diagnóstico por imagen , Neoplasias de la Próstata/diagnóstico por imagen , Estudios Retrospectivos
13.
Pediatr Int ; 64(1): e15371, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36166642

RESUMEN

BACKGROUND: The relationship between serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and the clinical features of patients with Kawasaki disease (KD) has been the subject of research. Recent studies have revealed that serum NT-proBNP levels vary with age. We therefore aimed to determine the utility of age-stratified cut-off values for NT-proBNP in predicting coronary artery lesions (CALs) in patients with KD. METHODS: We retrospectively assessed the electronic medical records of patients who were hospitalized for KD or incomplete KD between January 1, 2015, and August 31, 2019. The patients were divided into high and normal NT-proBNP groups using age-stratified cut-off based on serum NT-proBNP levels measured immediately before KD treatment initiation. RESULTS: The study comprised 242 cases, including 71 and 171 cases in high and normal NT-proBNP groups, respectively. Thirty-seven of them (15.3%) were resistant to treatment; 15 (6.2%) had CALs, with a higher incidence in the high NT-proBNP group than in the normal NT-proBNP group. On multivariate logistic regression analysis, high serum NT-proBNP levels were significantly correlated to CALs (OR, 9.76; 95% CI, 2.64-36.2). On logistic regression analysis to compare the predictive accuracy of the age-stratified and fixed cut-off for CALs, the age-stratified cut-off values showed a larger area under the receiver operating characteristic curve than fixed cut-off value. CONCLUSIONS: Based on age-stratified cut-off values for serum NT-proBNP, high NT-proBNP levels at the time of diagnosis were significantly associated with CALs in patients with KD. Higher predictive accuracy for CALs of the age-stratified cut-off values was also suggested.


Asunto(s)
Síndrome Mucocutáneo Linfonodular , Humanos , Estudios Retrospectivos , Biomarcadores , Síndrome Mucocutáneo Linfonodular/complicaciones , Péptido Natriurético Encefálico , Fragmentos de Péptidos , Curva ROC
14.
N Engl J Med ; 378(11): 995-1003, 2018 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-29539291

RESUMEN

BACKGROUND: Corneal endothelial cell (CEC) disorders, such as Fuchs's endothelial corneal dystrophy, induce abnormal corneal hydration and result in corneal haziness and vision loss known as bullous keratopathy. We investigated whether injection of cultured human CECs supplemented with a rho-associated protein kinase (ROCK) inhibitor into the anterior chamber could increase CEC density. METHODS: We performed an uncontrolled, single-group study involving 11 persons who had received a diagnosis of bullous keratopathy and had no detectable CECs. Human CECs were cultured from a donor cornea; a total of 1×106 passaged cells were supplemented with a ROCK inhibitor (final volume, 300 µl) and injected into the anterior chamber of the eye that was selected for treatment. After the procedure, patients were placed in a prone position for 3 hours. The primary outcome was restoration of corneal transparency, with a CEC density of more than 500 cells per square millimeter at the central cornea at 24 weeks after cell injection. Secondary outcomes were a corneal thickness of less than 630 µm and an improvement in best corrected visual acuity equivalent to two lines or more on a Landolt C eye chart at 24 weeks after cell injection. RESULTS: At 24 weeks after cell injection, we recorded a CEC density of more than 500 cells per square millimeter (range, 947 to 2833) in 11 of the 11 treated eyes (100%; 95% confidence interval [CI], 72 to 100), of which 10 had a CEC density exceeding 1000 cells per square millimeter. A corneal thickness of less than 630 µm (range, 489 to 640) was attained in 10 of the 11 treated eyes (91%; 95% CI, 59 to 100), and an improvement in best corrected visual acuity of two lines or more was recorded in 9 of the 11 treated eyes (82%; 95% CI, 48 to 98). CONCLUSIONS: Injection of human CECs supplemented with a ROCK inhibitor was followed by an increase in CEC density after 24 weeks in 11 persons with bullous keratopathy. (Funded by the Japan Agency for Medical Research and Development and others; UMIN number, UMIN000012534 .).


Asunto(s)
Córnea/citología , Enfermedades de la Córnea/terapia , Trasplante de Córnea , Células Endoteliales/trasplante , Inhibidores de Proteínas Quinasas/uso terapéutico , Quinasas Asociadas a rho/antagonistas & inhibidores , Anciano , Anciano de 80 o más Años , Células Cultivadas , Terapia Combinada , Córnea/anatomía & histología , Córnea/cirugía , Enfermedades de la Córnea/tratamiento farmacológico , Enfermedades de la Córnea/cirugía , Células Endoteliales/metabolismo , Femenino , Humanos , Presión Intraocular , Masculino , Persona de Mediana Edad
15.
Opt Express ; 29(7): 10104-10116, 2021 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-33820144

RESUMEN

We developed a high-speed and high-efficiency narrow-width metal-oxide-semiconductor (MOS) capacitor-type Si optical modulator (Si-MOD) by applying TM optical mode excitation. We designed and fabricated an optical-mode-converter structure from TE to TM mode. Even in the case of a 200-nm width, the Si MOS-MOD showed high-modulation efficiency in TM mode (about 0.18 Vcm), and the electrical capacitance decreased as the MOS junction width decreased. We also demonstrated high-speed operation at 32 Gbps and 40 Gbps for the 30-µm-long Si MOS-MOD in TM mode.

16.
Opt Lett ; 46(6): 1277-1280, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33720166

RESUMEN

We have directly generated optical pulses having a duration of 0.56 ps with a peak power of 25 W by gain switching of multi-section semiconductor lasers in which the optimized lengths of the absorption and gain regions were 50 and 200 µm, respectively. Even though the experiment was conducted via impulsive optical pumping at a low temperature, we observed that the multi-section gain switching suppresses the low-energy tail and chirping inherent to conventional gain switching in single-section lasers and is useful in direct short-pulse generation.

17.
Exp Eye Res ; 206: 108524, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33662354

RESUMEN

Although diurnal variations have been observed in tear film parameters in various species, the molecular mechanisms that control circadian tear secretion remain unclear. The aim of our study was to evaluate the role of clock genes in the lacrimal gland (LG) in regulation of tear secretion. Tear volume was measured by cotton thread test in core clock genes deficient (Cry1-/-Cry2-/--) mice which are behaviorally arrhythmic. Real-time quantitative RT-PCR was used to examine expression profiles of core clock genes in the LG including Per1, Per2, Per3, Clock, Bmal1. All experiments were performed under a 12 h of light and 12 h of darkness (LD) and constant dark (DD) conditions. Under both LD and DD conditions, diurnal and circadian rhythms were observed in tear secretion of wild-type mice with tear volume increased in the objective and subjective night while disruption in diurnal and circadian variations of tear secretion were found in Cry1-/-Cry2-/--mice. In wild-type mice, the expression level of major clock genes in the LG showed oscillatory patterns under both LD and DD conditions. In contrast, expression clock genes in the lacrimal gland of Cry1-/-Cry2-/-- mice showed complete loss of oscillation regardless of environmental light conditions. These findings confirmed the presence of diurnal and circadian rhythms of tear secretion and provided evidences supporting a critical role for the clock in the control of tear secretion.


Asunto(s)
Relojes Circadianos/fisiología , Síndromes de Ojo Seco/genética , Proteínas del Ojo/genética , Aparato Lagrimal/metabolismo , Lágrimas/metabolismo , Animales , Modelos Animales de Enfermedad , Síndromes de Ojo Seco/metabolismo , Proteínas del Ojo/biosíntesis , Masculino , Ratones , Ratones Endogámicos C57BL , ARN Mensajero/genética
18.
Phys Chem Chem Phys ; 23(6): 3866-3873, 2021 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-33538733

RESUMEN

We have investigated the S adsorption behaviours on Pt (average particle diameter of ∼2.6 nm) and Pt3Co (∼3.0 nm) anode and cathode electrode catalysts in polymer electrolyte fuel cells (PEFCs) under working conditions for the fresh state just after the aging process and also the degraded state after accelerated degradation tests (ADT), by studying near ambient pressure hard X-ray photoelectron spectroscopy (HAXPES). S 1s HAXPES of both the anode and cathode electrodes shows not only the principal S species from the sulfonic acid group (-SO3H) in the Nafion electrolyte but also other characteristic S species such as zero-valent S (S0) adsorbed on the carbon support and anionic S (S2-) adsorbed on the Pt electrode. The S2- species on Pt should be ascribed to S contamination poisoning the Pt catalyst electrode. The S2- species on the cathode can be oxidatively removed by applying a high cathode-anode bias voltage (≥0.8 V) to form SO32-, while at the anode the S2- species cannot be eliminated because of reductive environment in hydrogen gas. The important finding is the difference in S adsorption behaviours between the Pt/C and Pt3Co/C electrodes after ADT. After ADT, the Pt/C anode electrode exhibits much larger S2- adsorption than the Pt3Co/C anode electrode. This indicates that the Pt3Co/C anode is more desirable than the Pt/C one from the viewpoint of S poisoning. The reason for more tolerance of the Pt3Co/C anode catalyst against S poisoning after ADT can be ascribed to the more negative charge of the surface Pt atoms in the Pt3Co/C catalyst than those in the Pt/C one, thus yielding a weaker interaction between the surface Pt and the anionic S species as S2-, SO32-, and SO42-. A similar behaviour was observed also in the cathode catalyst. The present findings will nevertheless provide important information to design novel Pt-based PEFC electrodes with higher performance and longer durability.

19.
Ann Rheum Dis ; 79(5): 657-665, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32238385

RESUMEN

OBJECTIVES: Genome-wide meta-analyses of clinically defined gout were performed to identify subtype-specific susceptibility loci. Evaluation using selection pressure analysis with these loci was also conducted to investigate genetic risks characteristic of the Japanese population over the last 2000-3000 years. METHODS: Two genome-wide association studies (GWASs) of 3053 clinically defined gout cases and 4554 controls from Japanese males were performed using the Japonica Array and Illumina Array platforms. About 7.2 million single-nucleotide polymorphisms were meta-analysed after imputation. Patients were then divided into four clinical subtypes (the renal underexcretion type, renal overload type, combined type and normal type), and meta-analyses were conducted in the same manner. Selection pressure analyses using singleton density score were also performed on each subtype. RESULTS: In addition to the eight loci we reported previously, two novel loci, PIBF1 and ACSM2B, were identified at a genome-wide significance level (p<5.0×10-8) from a GWAS meta-analysis of all gout patients, and other two novel intergenic loci, CD2-PTGFRN and SLC28A3-NTRK2, from normal type gout patients. Subtype-dependent patterns of Manhattan plots were observed with subtype GWASs of gout patients, indicating that these subtype-specific loci suggest differences in pathophysiology along patients' gout subtypes. Selection pressure analysis revealed significant enrichment of selection pressure on ABCG2 in addition to ALDH2 loci for all subtypes except for normal type gout. CONCLUSIONS: Our findings on subtype GWAS meta-analyses and selection pressure analysis of gout will assist elucidation of the subtype-dependent molecular targets and evolutionary involvement among genotype, phenotype and subtype-specific tailor-made medicine/prevention of gout and hyperuricaemia.


Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Aldehído Deshidrogenasa Mitocondrial/genética , Predisposición Genética a la Enfermedad/etnología , Estudio de Asociación del Genoma Completo , Gota/genética , Proteínas de Neoplasias/genética , Estudios de Casos y Controles , Sitios Genéticos , Genotipo , Gota/epidemiología , Humanos , Incidencia , Japón , Masculino , Fenotipo , Pronóstico , Valores de Referencia , Medición de Riesgo , Índice de Severidad de la Enfermedad
20.
Opt Express ; 28(22): 33123-33134, 2020 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-33114981

RESUMEN

We studied a high-speed electro-absorption optical modulator (EAM) of a Ge layer evanescently coupled with a Si waveguide (Si WG) of a lateral pn junction for high-bandwidth optical interconnect. By decreasing the widths of selectively grown Ge layers below 1 µm, we demonstrated a high-speed modulation of 56 Gbps non-return-to-zero (NRZ) and 56 Gbaud pulse amplitude modulation 4 (PAM4) EAM operation in the C-band wavelengths, in contrast to the L-band wavelengths operations in previous studies on EAMs of pure Ge on Si. From the photoluminescence and Raman analyses, we confirmed an increase in the direct bandgap energy for such a submicron Ge/Si stack structure. The operation wavelength for the Ge/Si stack structure of a Ge/Si EAM was optimized by decreasing the device width below 1-µm and setting the post-growth anneal condition, which would contribute to relaxing the tensile-strain of a Ge layer on a Si WG and broadening the optical bandwidths for Franz-Keldysh (FK) effect with SiGe alloy formation.

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