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1.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(8): 851-858, 2023 Aug 24.
Artículo en Chino | MEDLINE | ID: mdl-37583334

RESUMEN

Objective: To investigate the impact of combined use and timing of arterial-venous extracorporeal membrane oxygenation (VA-ECMO) with intra-aortic balloon pump (IABP) on the prognosis of patients with acute myocardial infarction complicated with cardiogenic shock (AMICS). Methods: This was a prospective cohort study, patients with acute myocardial infarction and cardiogenic shock who received VA-ECMO support from the Heart Center of Lanzhou University First Hospital from March 2019 to March 2022 in the registration database of the Chinese Society for Extracorporeal Life Support were enrolled. According to combination with IABP and time point, patients were divided into VA-ECMO alone group, VA-ECMO+IABP concurrent group and VA-ECMO+IABP non-concurrent group. Data from 3 groups of patients were collected, including the demographic characteristics, risk factors, ECG and echocardiographic examination results, critical illness characteristics, coronary intervention results, VA-ECMO related parameters and complications were compared among the three groups. The primary clinical endpoint was all-cause death, and the safety indicators of mechanical circulatory support included a decrease in hemoglobin greater than 50 g/L, gastrointestinal bleeding, bacteremia, lower extremity ischemia, lower extremity thrombosis, acute kidney injury, pulmonary edema and stroke. Kaplan-Meier survival curves were used to analyze the survival outcomes of patients within 30 days of follow-up. Using VA-ECMO+IABP concurrent group as reference, multivariate Cox regression model was used to evaluate the effect of the combination of VA-ECMO+IABP at different time points on the prognosis of AMICS patients within 30 days. Results: The study included 68 AMICS patients who were supported by VA-ECMO, average age was (59.8±10.8) years, there were 12 female patients (17.6%), 19 cases were in VA-ECMO alone group, 34 cases in VA-ECMO+IABP concurrent group and 15 cases in VA-ECMO+IABP non-concurrent group. The success rate of ECMO weaning in the VA-ECMO+IABP concurrent group was significantly higher than that in the VA-ECMO alone group and the VA-ECMO+IABP non-concurrent group (all P<0.05). Compared with the ECMO+IABP non-concurrent group, the other two groups had shorter ECMO support time, lower rates of acute kidney injury complications (all P<0.05), and lower rates of pulmonary edema complications in the ECMO alone group (P<0.05). In-hospital survival rate was significantly higher in the VA-ECMO+IABP concurrent group (28 patients (82.4%)) than in the VA-ECMO alone group (9 patients) and VA-ECMO+IABP non-concurrent group (7 patients) (all P<0.05). The survival rate up to 30 days of follow-up was also significantly higher surviving patients within were in the ECMO+IABP concurrent group (26 cases) than in VA-ECMO alone group (9 patients) and VA-ECMO+IABP non-concurrent group (4 patients) (all P<0.05). Multivariate Cox regression analysis showed that compared with the concurrent use of VA-ECMO+IABP, the use of VA-ECMO alone and non-concurrent use of VA-ECMO+IABP were associated with increased 30-day mortality in AMICS patients (HR=2.801, P=0.036; HR=2.985, P=0.033, respectively). Conclusions: When VA-ECMO is indicated for AMICS patients, combined use with IABP at the same time can improve the ECMO weaning rate, in-hospital survival and survival at 30 days post discharge, and which does not increase additional complications.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Infarto del Miocardio , Edema Pulmonar , Humanos , Femenino , Persona de Mediana Edad , Anciano , Choque Cardiogénico/terapia , Choque Cardiogénico/complicaciones , Oxigenación por Membrana Extracorpórea/efectos adversos , Oxigenación por Membrana Extracorpórea/métodos , Edema Pulmonar/complicaciones , Cuidados Posteriores , Estudios Prospectivos , Alta del Paciente , Infarto del Miocardio/complicaciones , Infarto del Miocardio/terapia , Contrapulsador Intraaórtico/efectos adversos , Contrapulsador Intraaórtico/métodos , Resultado del Tratamiento , Estudios Retrospectivos
3.
Zhonghua Xin Xue Guan Bing Za Zhi ; 48(8): 641-647, 2020 Aug 24.
Artículo en Chino | MEDLINE | ID: mdl-32847319

RESUMEN

Objective: To investigate the safety and efficacy of regional transport to percutaneous coronary intervention(PCI) hospitals from non-PCI hospitals after thrombolysis in patients with acute ST-segment elevation myocardial infarction(STEMI) in northwest China. Methods: In this retrospective study, 1 062 STEMI patients who were transferred from non-PCI hospitals within 24 hours from symptom onset, during January 2015 and January 2019 in the First Hospital of Lanzhou University, were included. According to the treatment strategy, they were divided into two groups, namely intravenous thrombolysis combined with PCI group(n=240), and primary PCI group(n=822). Observation endpoint were in-hospital adverse cardiovascular and cerebrovascular events and bleeding events, Including all-cause death, ischemic stroke, malignant arrhythmia, intracranial hemorrhage and hemorrhage with hemoglobin decrease≥50 g/L. Results: A total of 1 062 STEMI patients were included(age was (61±12) years old), with 905 males (85.2%). The proportion of grade 0 TIMI blood flow in the primary PCI group before operation was significantly higher than that in the thrombolysis combined with PCI group(63.0%(518/822) vs. 36.3%(87/240), P<0.001). Compared with primary PCI group, the time from symptom onset to first medical contact(2.11(1.00, 4.00)hours vs.3.00(1.13, 7.07)hours, P<0.001) and reperfusion in thrombolysis combined with PCI group(3.07(1.83, 4.87)hours vs. 6.92(4.07, 11.15) hours, P<0.001) were significantly shorter. The proportion of all-cause death was significantly higher in the primary PCI group than that in the thrombolysis combined with PCI group (1.8%(15/822) vs. 0, P=0.03). There was no significant difference in hemorrhage, ischemic stroke and malignant arrhythmia between the two groups(all P>0.05). Conclusions: For STEMI patients initially hospitalized in non-PCI hospitals, regional transport combined with PCI is feasible and effective. It does not significantly increase the risk of bleeding and cardiovascular and cerebrovascular events, with shorter time from symptom onset to myocardial reperfusion.


Asunto(s)
Angioplastia Coronaria con Balón , Infarto del Miocardio , Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST/terapia , Anciano , China , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Terapia Trombolítica , Resultado del Tratamiento
4.
Eur Rev Med Pharmacol Sci ; 24(1): 369-375, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31957851

RESUMEN

OBJECTIVE: To observe the intervention effect of circular ribonucleic acid (circRNA) 010567 on myocardial infarction (MI)-induced myocardial fibrosis (MF) in rats, and to explore whether its mechanism of action is related to the regulation on the transforming growth factor-ß1 (TGF-ß1) signaling pathway. MATERIALS AND METHODS: The rat model of acute MI was established using ligation of the left anterior descending coronary artery. Model rats were randomly divided into circRNA 010567 siRNA group and Model group, with sham operation group as Control group. The effects of circRNA 010567 on the cardiac function, MF, myocardial apoptosis, mRNA, and protein expression levels of TGF-ß1 and Smad3 in heart tissues of MI rats were detected using the small animal ultrasound system, Masson staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, reverse transcription-polymerase chain reaction (RT-PCR), and Western blotting, respectively. RESULTS: Compared with Control group, Model group had significantly decreased cardiac function, significantly lower left ventricular ejection fraction (LVEF), and left ventricular fractional shortening (LVFS), markedly increased left ventricular end-diastolic diameter (LVDd), and left ventricular end-systolic diameter (LVDs), severe MF, as well as a significantly higher apoptosis rate of myocardial cells, and evidently increased mRNA and protein levels of TGF-ß1 and Smad3 in heart tissues. Compared with Model group, circRNA 010567 siRNA group had evidently improved cardiac function, significantly higher LVEF and LVFS, markedly decreased LVDd and LVDs, alleviated MF, a significantly lower apoptosis rate of myocardial cells, and evidently decreased mRNA and protein levels of TGF-ß1 and Smad3 in heart tissues. CONCLUSIONS: CircRNA 010567 siRNA can improve the cardiac function, alleviate the MF, and inhibit the myocardial apoptosis, thereby further suppressing MI-induced MF, whose mechanism may be related to the inhibition on the TGF-ß1 signaling pathway.


Asunto(s)
Infarto del Miocardio/metabolismo , ARN Circular/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Enfermedad Aguda , Animales , Apoptosis , Modelos Animales de Enfermedad , Masculino , Infarto del Miocardio/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal , Factor de Crecimiento Transformador beta1/genética
5.
Eur Rev Med Pharmacol Sci ; 23(22): 10107-10114, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31799682

RESUMEN

OBJECTIVE: To elucidate whether circHIPK3 could inhibit proliferation and induce apoptosis of cardiomyocytes via binding to miRNA-124-3p, thus aggravating myocardial ischemia/reperfusion (IR) injury. MATERIALS AND METHODS: CircHIPK3 expression in HCM cells simulated with myocardial I/R was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Influences of circHIPK3 on myocardial injury marker levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in the in vitro model of myocardial I/R were evaluated using the relative commercial kits. The regulatory effects of circHIPK3 on proliferative ability and apoptosis of simulated HCM cells were examined by Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Dual-Luciferase reporter gene assay was conducted to verify the binding of circHIPK3 to miRNA-124-3p. Finally, the roles of the circHIPK3/miRNA-124-3p axis in regulating apoptotic gene expressions and cardiomyocyte repair after myocardial I/R were explored. RESULTS: CircHIPK3 was highly expressed in HCM cells with simulated myocardial I/R relative to those with normoxic treatment. The overexpression of circHIPK3 in simulated HCM cells decreased levels of LDH, SOD and GSH-PX, whereas increased the MDA level. Inhibited proliferation and accelerated apoptosis were observed in simulated HCM cells overexpressing circHIPK3. Western blot analyses illustrated that circHIPK3 overexpression upregulated pro-apoptotic Bax, and downregulated anti-apoptotic Bcl-2. Subsequently, we confirmed the binding between circHIPK3 and miRNA-124-3p. Rescue experiments demonstrated that circHIPK3 overexpression reversed the protective effects of miRNA-124-3p on myocardial I/R and cardiomyocyte apoptosis. CONCLUSIONS: CircHIPK3 inhibits proliferative ability and induces apoptosis of cardiomyocytes after myocardial I/R injury by binding to miRNA-124-3p, which may serve as a potential therapeutic target for I/R.


Asunto(s)
MicroARNs/genética , Daño por Reperfusión Miocárdica/genética , Miocitos Cardíacos/citología , ARN Circular/genética , Apoptosis , Proliferación Celular , Células Cultivadas , Glutatión Peroxidasa/metabolismo , Humanos , L-Lactato Deshidrogenasa/metabolismo , Malondialdehído/metabolismo , Modelos Biológicos , Daño por Reperfusión Miocárdica/etiología , Miocitos Cardíacos/química , Superóxido Dismutasa/metabolismo , Regulación hacia Arriba
6.
Eur Rev Med Pharmacol Sci ; 23(21): 9642-9650, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31773715

RESUMEN

OBJECTIVE: The aim of this study was to investigate the effects of butylphthalide on oxidative stress and inflammatory response in rats with myocardial infarction through the protein kinase B/nuclear factor E2-related factor 2 (Akt/Nrf2) signaling pathway. MATERIALS AND METHODS: A total of 36 Sprague-Dawley rats were randomly divided into three groups, including sham group (n=12), model group (n=12) and butylphthalide group (n=12). In the sham group, the heart was exposed, and normal saline was intraperitoneally injected after the operation. In the model group, acute myocardial infarction (AMI) model was established, and normal saline was intraperitoneally injected after the operation. In the butylphthalide group, AMI model was established, and butylphthalide was intraperitoneally injected after the operation. After intervention for 4 weeks, the rats were killed, and the samples were collected. The morphology of heart tissues was observed via hematoxylin-eosin (HE) staining. The expression of nicotinamide adenine dinucleotide phosphate oxidase-1 (NOX-1) was detected via immunohistochemistry. The protein expressions of phosphorylated Akt (p-Akt) and p-Nrf2 were detected via Western blotting. Moreover, the content of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) was detected via enzyme-linked immunosorbent assay (ELISA). The messenger ribonucleic acid (mRNA) expression levels of IL-1ß, TNF-α and NOX-1 were detected via quantitative Polymerase Chain reaction (qPCR). Furthermore, the apoptosis rate of the cells was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: The morphology of heart tissues was significantly damaged in the model group and butylphthalide group compared with the sham group. However, it was significantly improved in the butylphthalide group when compared with the model group. The expression level of NOX-1 increased markedly in the model group and butylphthalide group compared with the sham group (p<0.05). However, it was remarkably reduced in the butylphthalide group compared with the model group (p<0.05). Meanwhile, the protein expression levels of p-Akt and p-Nrf2 were significantly higher in the model group and butylphthalide group than those of the sham group (p<0.05). However, the protein expression levels of p-Akt and p-Nrf2 in the butylphthalide group were remarkably lower than the model group (p<0.05). The mRNA expression levels of IL-1ß, TNF-α and NOX-1 were markedly higher in the model group and butylphthalide group than those of the sham group (p<0.05). However, they remarkably declined in the butylphthalide group compared with the model group (p<0.05). In addition, the content of IL-1ß and TNF-α increased in the model group and butylphthalide group when compared with the sham group (p<0.05). The content of IL-1ß and TNF-α in the butylphthalide group was significantly lower than the model group (p<0.05). Furthermore, the apoptosis rate was significantly higher in the model group and butylphthalide group than the sham group (p<0.05), which was significantly lower in the butylphthalide group than the model group (p<0.05). CONCLUSIONS: Butylphthalide inhibits inflammatory and oxidative stress responses after AMI by regulating the Akt/Nrf2 signaling pathway, thereby inhibiting myocardial apoptosis and benefiting the morphological repair of myocardial tissues.


Asunto(s)
Benzofuranos/farmacología , Inflamación/tratamiento farmacológico , Infarto del Miocardio/tratamiento farmacológico , Factor 2 Relacionado con NF-E2/metabolismo , Fármacos Neuroprotectores/farmacología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Animales , Modelos Animales de Enfermedad , Inflamación/metabolismo , Inflamación/patología , Masculino , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Factor 2 Relacionado con NF-E2/genética , Estrés Oxidativo/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/genética , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos
7.
Opt Express ; 22(21): 26092-7, 2014 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-25401641

RESUMEN

We demonstrate experimentally Manchester (MC) coding based W-band (75 - 110 GHz) radio-over-fiber (ROF) system to reduce the low-frequency-components (LFCs) signal distortion generated by two independent low-cost lasers using spectral shaping. Hence, a low-cost and higher performance W-band ROF system is achieved. In this system, direct-beating of two independent low-cost CW lasers without frequency tracking circuit (FTC) is used to generate the millimeter-wave. Approaches, such as delayed self-heterodyne interferometer and heterodyne beating are performed to characterize the optical-beating-interference sub-terahertz signal (OBIS). Furthermore, W-band ROF systems using MC coding and NRZ-OOK are compared and discussed.


Asunto(s)
Tecnología de Fibra Óptica/instrumentación , Rayos Láser , Telecomunicaciones/instrumentación , Tecnología Inalámbrica/instrumentación , Diseño de Equipo
8.
Opt Express ; 22(11): 12779-84, 2014 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-24921473

RESUMEN

In this work, a scalable and continuous upgradable convergent optical access network is proposed. By using a multi-wavelength coherent comb source and a programmable waveshaper at the central office (CO), optical millimeter-wave (mm-wave) signals of different frequencies (from baseband to > 100 GHz) can be generated. Hence, it provides a scalable and continuous upgradable solution for end-user who needs 60 GHz wireless services now and > 100 GHz wireless services in the future. During the upgrade, user only needs to upgrade their optical networking unit (ONU). A programmable waveshaper is used to select the suitable optical tones with wavelength separation equals to the desired mm-wave frequency; while the CO remains intact. The centralized characteristics of the proposed system can easily add any new service and end-user. The centralized control of the wavelength makes the system more stable. Wired data rate of 17.45 Gb/s and w-band wireless data rate up to 3.36 Gb/s were demonstrated after transmission over 40 km of single-mode fiber (SMF).

9.
Opt Express ; 18(2): 473-8, 2010 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-20173867

RESUMEN

Fiber-to-the-antenna (FTTA) system can be a cost-effective technique for distributing high frequency signals from the head-end office to a number of remote antenna units via passive optical splitter and propagating through low-loss and low-cost optical fibers. Here, we experimentally demonstrate an optical ultra-wideband (UWB) - impulse radio (IR) FTTA system for in-building and in-home applications. The optical UWB-IR wireless link is operated in the W-band (75 GHz - 110 GHz) using our developed near-ballistic unitraveling-carrier photodiode based photonic transmitter (PT) and a 10 GHz mode-locked laser. 2.5 Gb/s UWB-IR FTTA systems with 1,024 high split-ratio and transmission over 300 m optical fiber are demonstrated using direct PT modulation.


Asunto(s)
Redes de Comunicación de Computadores/instrumentación , Fibras Ópticas , Procesamiento de Señales Asistido por Computador/instrumentación , Telecomunicaciones/instrumentación , Transductores , Diseño de Equipo , Análisis de Falla de Equipo , Microondas
10.
Rev Sci Instrum ; 80(1): 014701, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19191453

RESUMEN

A prototype small impact rotary motor has been fabricated based on a newly developed torsional actuator which is 15.0 mm long and 1.0 mm in diameter. The motor can rotate when it is powered with a saw-shaped voltage. The experimental results show that its angular speed is proportional to both the driving voltage's amplitude and the frequency under 1 kHz. The large nonlinearity occurs at higher driving frequency due to the resonance of the partial mechanical structure of the motor. The motor can rotate at a speed of 90 rpm with a saw-shaped driving voltage of 600 V(p.-p.) at 8 kHz, and produce a stall torque of 80 microN m with 1000 V(p.-p.) at 3 kHz.

12.
J Biol Phys ; 29(2-3): 335-8, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23345853

RESUMEN

The complex refractive indices of two benchmark nematic liquid crystal,4-4 '-n-pentyl-cyanobiphenyl (5CB) and 4-(trans-4'pentylcyclohexyl)-benzonitrile (PCH5) have been determinedin the frequency range from 0.2 to 0.8 THz. The technique of coherent THztime-domain spectroscopy (THz-TDS) was used. We show that the birefringenceof 5CB is in the range of 0.15 to 0.21, while that of PCH is from 0.01 to0.08. Both liquid crystals exhibit relatively small absorption in thisfrequency range. The large birefringence of 5CB indicates possible applications of liquid-crystal-based devices for modulation and polarizationcontrol of electromagnetic radiation in the THz frequency range.

13.
Neurology ; 59(7): 1094-8, 2002 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-12370473

RESUMEN

The authors evaluated epidermal nerve density (END) and thermal thresholds in 18 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). END of patients with CIDP were lower than those of controls (4.5 +/- 2.9 vs 10.5 +/- 3.9 fibers/mm, p < 0.001). Reduced END were associated with autonomic symptoms. Thermal thresholds of patients with CIDP were elevated (88.2% for warm stimuli and 70.6% for cold stimuli). Patients with CIDP have small-fiber sensory and autonomic neuropathies.


Asunto(s)
Epidermis/inervación , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Frío , Epidermis/patología , Epidermis/fisiología , Femenino , Calor , Humanos , Masculino , Persona de Mediana Edad , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/patología , Umbral Sensorial/fisiología , Estadísticas no Paramétricas
14.
Neurology ; 57(7): 1316-8, 2001 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-11591857

RESUMEN

The authors describe two patients with acute sensory ataxic neuropathy. Both had a profound loss of proprioception and generalized areflexia. High titers of monospecific anti-GD1b IgG antibody were detected in their sera during the acute phase. Sensory ataxia resolved within 2 weeks after the onset. Taken together with the induction of experimental sensory ataxic neuropathy sensitized with GD1b ganglioside, GD1b may be a target molecule for autoantibody in some patients with acute sensory ataxic neuropathy.


Asunto(s)
Ataxia/inmunología , Gangliósidos/inmunología , Inmunoglobulina G/sangre , Enfermedad Aguda , Adulto , Especificidad de Anticuerpos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Conducción Nerviosa , Neuronas Aferentes/fisiología
15.
Neuroreport ; 12(4): 787-92, 2001 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-11277584

RESUMEN

Patients with peripheral neuropathy have symptoms involving small-diameter nociceptive nerves and elevated thermal thresholds. Nociceptive nerves terminate in the epidermis of the skin and are readily demonstrated with the neuronal marker, protein gene product 9.5 (PGP 9.5). To investigate the pathological characteristics of elevated thermal thresholds, we performed PGP 9.5 immunocytochemistry on 3 mm punch skin biopsies (the forearm and the leg) from 55 normal subjects and 35 neuropathic patients. Skin innervation was evaluated by quantifying epidermal nerve densities. Epidermal nerve densities were reduced in neuropathic patients compared to normal subjects. Epidermal nerve densities were variably correlated with thermal thresholds. The proportion of neuropathic patients with reduced epidermal nerve densities was larger than the proportion of neuropathic patients with elevated thermal thresholds. These results indicated that degeneration of epidermal nerve terminals preceded the elevation of thermal thresholds. Skin biopsy together with immunocytochemical demonstration of epidermal innervation offers a new approach to evaluate small-fiber sensory neuropathy.


Asunto(s)
Epidermis/inervación , Degeneración Nerviosa/patología , Nociceptores/patología , Enfermedades del Sistema Nervioso Periférico/patología , Adulto , Anciano , Biopsia , Estudios de Cohortes , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Nociceptores/química , Umbral del Dolor , Termorreceptores/química , Termorreceptores/patología , Tioléster Hidrolasas/análisis , Ubiquitina Tiolesterasa
16.
Appl Opt ; 37(15): 3282-5, 1998 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-18273283

RESUMEN

As far as we know this is the first report on picosecond green-light generation from an actively mode-locked diode-pumped self-doubling neodymium yttrium aluminum borate (NYAB) laser. The pulse width is approximately 100 ps and is limited by imperfect antireflection coating and the intracavity doubling effect. The green average output power of this laser for mode-locked operation was more than 12 times higher than that for the continuous wave NYAB laser. The polarization state of the laser can be switched from ordinary to extraordinary rays by displacement of the pump spot. The polarization ratio can be better than 200 without any intracavity polarization element.

17.
Opt Lett ; 21(14): 1058-60, 1996 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-19876251

RESUMEN

Through analysis of transient autocorrelation traces, we show that intracavity dispersion significantly affects the number of initially oscillating modes as well as the buildup of passive mode locking in picosecond and femtosecond lasers.

18.
Opt Lett ; 20(2): 163-5, 1995 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-19859121

RESUMEN

We show that, for a cw passively mode-locked picosecond Ti:sapphire/DDI laser, the first autocorrelation trace with negligible cw background occurs at a delay time of 20 mu;s, or 1600 round trips from the first relaxationoscillation peak. The trace suggests that the pulse consists of a primary pulse as short as 4.4 ps and of small secondary pulses that form a much wider pedestal of the trace, each containing approximately 50% of the photon energy. Nearly transform-limited approximately 5-ps-wide Gaussian pulses were observed at a delay time of 40 mu;s. After 45 mu;s, the optical spectrum broadened considerably, and the time-bandwidth product increased to 4 in the steady state (after 60 micros).

20.
Opt Lett ; 20(11): 1292-4, 1995 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-19859503

RESUMEN

We report, for the first time to our knowledge, generation of a tunable miltiterahertz modulation signal on an optical carrier directly from a single laser source. The modulation frequency, which can be tuned from 0.15 THz to more than 7 THz, is the beat note obtained by varying the spectral separation between the coaxial two-color output of a two-wavelength laser-diode array from 0.32 to 17 nm. The frequency characteristics of the terahertz beat note are determined with a noncollinear intensity autocorrelator.

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