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1.
Acta Otolaryngol ; 140(5): 418-421, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32068453

RESUMEN

Background: It has been demonstrated that miRNAs play critical roles in the tumorigenesis and progression of various tumors.Objective: The purpose of this research was to determine the serum miR-632 levels in patients with laryngeal squamous cell carcinoma (LSCC) and to investigate its diagnostic and prognostic value.Materials and methods: We detected serum miR-632 levels in 162 LSCC patients and 42 healthy volunteers. The ROC curve was carried out to determine diagnostic accuracy.Results: We observed that serum miR-632 levels were upregulated in LSCC patients compared with healthy volunteers (p < .01). Subsequent results from ROC indicated that high sensitivity and specificity of serum miR-632 for diagnosing LSCC (area under the curve 0.8828). In addition, it was found that high expressions of serum miR-632 were significantly associated with advanced N stage (p = .020), histological grade (p = .001), and TNM stage (p = .014). Furthermore, patients with higher serum miR-632 expression had a shorter OS and DFS time than those with lower serum miR-632 levels.Conclusion: Our data revealed that serum miR-632 may be a potential noninvasive biomarker which may become a potential diagnostic and prognostic biomarker for LSCC patients.


Asunto(s)
Carcinoma de Células Escamosas/sangre , Neoplasias Laríngeas/sangre , MicroARNs/sangre , Biomarcadores de Tumor/sangre , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/mortalidad , Estudios de Casos y Controles , China/epidemiología , Femenino , Humanos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/mortalidad , Masculino , Persona de Mediana Edad
2.
Transl Biophotonics ; 2(3)2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37745902

RESUMEN

Intravascular photoacoustic/ultrasound (IVPA/US) is an emerging hybrid imaging modality that provides specific lipid detection and localization, while maintaining co-registered artery morphology, for diagnosis of vulnerable plaque in cardiovascular disease. However, current IVPA/US approaches based on a single-element transducer exhibit compromised performance for lipid detection due to the relatively low contrast of lipid absorption and conflicting detection bands for photoacoustic and ultrasound signals. Here, we present a dual-frequency IVPA/US catheter for highly sensitive detection and precision localization of lipids. The low frequency transducer provides enhanced photoacoustic sensitivity, while the high frequency transducer maintains state-of-the-art spatial resolution for ultrasound imaging. The boosted capability of IVPA/US imaging enables a multi-scale analysis of lipid distribution in swine with coronary atherosclerosis. The dual-frequency IVPA/US catheter has a diameter of 1 mm and flexibility to easily adapt to current catheterization procedures and is a significant step toward clinical diagnosis of vulnerable plaque.

3.
Opt Lett ; 44(15): 3841-3844, 2019 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-31368982

RESUMEN

Intravascular photoacoustic imaging can potentially improve the identification of lipid-laden atherosclerotic plaque. Most intravascular photoacoustic endoscopes use multimode fibers, which do not allow tight focusing of photons. Recent experiments on pulse propagation in multimode graded-index fibers have shown a nonlinear improvement in beam quality. Here, we harness this nonlinear phenomenon for fiber-delivery of nanosecond laser pulses. We built a photoacoustic catheter 1.4 mm outer diameter, offering a lateral resolution as fine as 30 µm within a depth range of 2.5 mm. Such resolution is one order of magnitude better than current multimode fiber-based intravascular photoacoustic catheters. At the same time, the delivered pulse energy can reach as high as 20 µJ, which is two orders of magnitude higher than that of an optical resolution photoacoustic endoscope built with a single mode fiber. These improvements are expected to promote the biomedical application of photoacoustic endoscopes which require both high resolution and high pulse energy.

4.
Oncol Lett ; 17(6): 5523-5528, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31186773

RESUMEN

Application values of CA125 combined with CA199 and ultrasound combined with computed tomography (CT) in the clinical diagnosis of ovarian cancer were compared. A retrospective analysis was performed on 168 ovarian cancer patients admitted to the Department of Gynecology in Jining No.1 People's Hospital from July 2013 to March 2016. Of the patients 107 with malignant tumors were in the malignant group, and 61 patients with benign tumors were in the benign group. Another 98 healthy controls in the same period were in the normal group. Chemiluminescence was used for the detection of levels of tumor markers CA125 and CA199 in the serum of all patients. CA125 combined with CA199 and color Doppler ultrasound combined with CT scan were used to diagnose and analyze the sensitivity, specificity, accuracy, and positive detection rate of ovarian cancer patients at different stages. The sensitivity, specificity and diagnostic coincidence rate of ultrasound combined with CT in the diagnosis of ovarian cancer were 97.20, 80.32 and 91.07%, respectively, which were significantly higher than the 92.52, 73.77 and 85.71% of serum CA125 combined with CA199. The positive detection rate of ultrasound combined with CT in the early diagnosis of ovarian cancer was 93.55%, higher than 83.87% of CA125 combined with CA199. The sensitivity, specificity, coincidence rate and positive detection rate of ultrasound combined with CT in the diagnosis were higher than those of CA125 combined with CA199. In the actual diagnosis process, these two diagnostic schemes can be selectively and comprehensively applied, so as to make a correct diagnosis, which is of great significance for reducing patient mortality.

5.
Biomed Opt Express ; 10(3): 1405-1419, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30891355

RESUMEN

Current diagnosis of prostate cancer relies on histological analysis of tissue samples acquired by biopsy, which could benefit from real-time identification of suspicious lesions. Photoacoustic tomography has the potential to provide real-time targets for prostate biopsy guidance with chemical selectivity, but light delivered from the rectal cavity has been unable to penetrate to the anterior prostate. To overcome this barrier, a urethral device with cylindrical illumination is developed for whole-prostate imaging, and its performance as a function of angular light coupling is evaluated with a prostate-mimicking phantom.

6.
J Cardiovasc Transl Res ; 12(3): 211-220, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30488332

RESUMEN

Intravascular photoacoustic-ultrasound (IVPA-US) imaging and near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) are two hybrid modalities that detect arterial lipid, with comparison necessary to understand the relative advantages of each. We performed in vivo and ex vivo IVPA-US imaging of the iliac arteries of Ossabaw swine with metabolic syndrome (MetS) and lean swine to investigate sensitivity for early-stage atherosclerosis. We repeated imaging ex vivo with NIRS-IVUS for comparison to IVPA-US and histology. Both modalities showed significantly greater lipid in MetS vs. lean swine, but only IVPA-US localized the lipid as perivascular. To investigate late-stage atherosclerosis, we performed ex vivo IVPA-US imaging of a human coronary artery with comparison to NIRS-IVUS and histology. Two advanced fibroatheromas were identified, with agreement between IVPA-measured lipid area and NIRS-derived lipid content. As confirmed histologically, IVPA-US has sensitivity to detect lipid content similar to NIRS-IVUS and provides additional depth resolution, enabling quantification and localization of lipid cores within plaques.


Asunto(s)
Aterosclerosis/diagnóstico por imagen , Arteria Ilíaca/diagnóstico por imagen , Lípidos/análisis , Síndrome Metabólico/diagnóstico por imagen , Técnicas Fotoacústicas , Placa Aterosclerótica , Espectroscopía Infrarroja Corta , Ultrasonografía Intervencional , Animales , Aterosclerosis/metabolismo , Modelos Animales de Enfermedad , Diagnóstico Precoz , Femenino , Humanos , Arteria Ilíaca/metabolismo , Masculino , Síndrome Metabólico/metabolismo , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Porcinos , Porcinos Enanos
7.
Medicine (Baltimore) ; 97(47): e13205, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30461621

RESUMEN

We investigated the effects of tonsillectomy by low-temperature plasma on the growth development and psychological behavior in children with obstructive sleep apnea hypopnea syndrome (OSAHS).This study included 72 moderate and severe OSAHS children with tonsils or adenoids hypertrophy, which were randomly assigned into either the study group (n = 36) or the control group (n = 36). Patients in study group underwent tonsillectomy by low-temperature plasma, while in the control group underwent tonsil-pecking, then the efficacy were compared.The time of surgery, VAS scores on postoperative day 1, 3, and 7 were significantly lower in the study group than in the control group, and the efficiency was significantly higher in the study group than the control group (P = .018). In the study group, the BMI was lower, the score of C-WISC (VIQ, PIQ, and FIQ) was higher, the score of CBCL social competence was higher and the score of behavioral questions was lower than that in the control group; differences were statistically significant (P = .022). The serum levels of IgA, IgG, and IgM, as well as the percentage of T lymphocytes, between the study group and the control group were not significantly different (P = .132).Tonsillectomy by low-temperature plasma was effective on the treatment of children with severe OSAHS, and could improve growth development and psychological behavior.


Asunto(s)
Coagulación con Plasma de Argón/métodos , Conducta Infantil/fisiología , Desarrollo Infantil , Apnea Obstructiva del Sueño , Tonsilectomía/métodos , Tonsila Faríngea/patología , Tonsila Faríngea/cirugía , Niño , Preescolar , Femenino , Humanos , Masculino , Tonsila Palatina/patología , Tonsila Palatina/cirugía , Polisomnografía/métodos , Periodo Posoperatorio , República de Corea , Apnea Obstructiva del Sueño/diagnóstico , Apnea Obstructiva del Sueño/fisiopatología , Apnea Obstructiva del Sueño/psicología , Resultado del Tratamiento
8.
Sci Rep ; 8(1): 2400, 2018 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-29402963

RESUMEN

Intravascular photoacoustic tomography is an emerging technology for mapping lipid deposition within an arterial wall for the investigation of the vulnerability of atherosclerotic plaques to rupture. By converting localized laser absorption in lipid-rich biological tissue into ultrasonic waves through thermoelastic expansion, intravascular photoacoustic tomography is uniquely capable of imaging the entire arterial wall with chemical selectivity and depth resolution. However, technical challenges, including an imaging catheter with sufficient sensitivity and depth and a functional sheath material without significant signal attenuation and artifact generation for both photoacoustics and ultrasound, have prevented in vivo application of intravascular photoacoustic imaging for clinical translation. Here, we present a highly sensitive quasi-collinear dual-mode photoacoustic/ultrasound catheter with elaborately selected sheath material, and demonstrated the performance of our intravascular photoacoustic tomography system by in vivo imaging of lipid distribution in rabbit aortas under clinically relevant conditions at imaging speeds up to 16 frames per second. Ex vivo evaluation of fresh human coronary arteries further confirmed the performance of our imaging system for accurate lipid localization and quantification of the entire arterial wall, indicating its clinical significance and translational capability.


Asunto(s)
Aterosclerosis/diagnóstico por imagen , Vasos Coronarios/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Lípidos/análisis , Técnicas Fotoacústicas/instrumentación , Placa Aterosclerótica/diagnóstico por imagen , Ultrasonografía Intervencional/métodos , Adulto , Animales , Aorta/diagnóstico por imagen , Aorta/metabolismo , Aorta/patología , Aterosclerosis/metabolismo , Aterosclerosis/patología , Materiales Biocompatibles/química , Catéteres , Vasos Coronarios/metabolismo , Vasos Coronarios/patología , Femenino , Humanos , Masculino , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patología , Poliuretanos/química , Conejos , Técnicas de Cultivo de Tejidos
9.
Int J Nanomedicine ; 12: 6461-6470, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28919747

RESUMEN

In this study, dual therapeutic-loaded GE11 peptide-conjugated liposomes were developed and applied to enhance therapeutic efficacies of standard-of-care regimens for the treatment of laryngeal cancer. The therapeutic strategy used here was a combination treatment with the chemotherapeutic docetaxel (DTX) and siRNA against the ABCG2 gene that regulates multidrug resistance in many tumor types. Liposome-encapsulated DTX/ABCG2-siRNA molecules were targeted to recognize tumor cells of squamous morphology by conjugation to the EGFR-targeting ligand, GE11. Targeted, drug-infused liposomes were nanosized and exhibited controlled release of DTX. Presence of GE11 peptides on liposomal surfaces enhanced the quantities of liposomal constructs taken up by Hep-2 laryngeal cancer cells. GE11 peptide-conjugated liposomes also enhanced cytotoxic effects against Hep-2 laryngeal cancer cells when compared to treatment with free DTX, thereby reducing IC50 values. Additionally, GE11 peptide-conjugated liposomes had significantly increased anti-tumor and apoptotic effects. Treatments with the GDSL nanoparticle formulation inhibited tumor growth in Hep-2 xenograft-bearing nude mouse models when compared to treatments with non-targeted NP constructs. Treatment of the mouse models with GE11 peptide-conjugated liposomes mitigated toxicities observed after treatment with free DTX. Taken together, liposomal encapsulation of DTX and ABCG2-siRNA improved the anti-tumor effects of treatment with free DTX in Hep-2 cell lines, and conjugation of GE11 peptides to liposomal constructs enhanced anti-tumor efficacies and specificities in laryngeal cancer cells.


Asunto(s)
Neoplasias Laríngeas/tratamiento farmacológico , Nanopartículas/química , Péptidos/química , ARN Interferente Pequeño/administración & dosificación , Taxoides/administración & dosificación , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Línea Celular Tumoral , Docetaxel , Sistemas de Liberación de Medicamentos/métodos , Células Hep G2 , Humanos , Membrana Dobles de Lípidos/química , Liposomas/administración & dosificación , Liposomas/química , Ratones Desnudos , Nanopartículas/administración & dosificación , Proteínas de Neoplasias/genética , Electricidad Estática , Ensayos Antitumor por Modelo de Xenoinjerto/métodos
10.
BMC Cancer ; 17(1): 477, 2017 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-28693517

RESUMEN

BACKGROUND: Jumonji C domain 2A (JMJD2A), as a histone demethylases, plays a vital role in tumorigenesis and progression. But, its functions and underlying mechanisms of JMJD2A in nasopharyngeal carcinoma (NPC) metabolism are remained to be clarified. In this study, we investigated glycolysis regulation by JMJD2A in NPC and the possible mechanism. METHODS: JMJD2A expression was detected by Western blotting and Reverse transcription quantitative real-time PCR analysis. Then, we knocked down and ectopically expressed JMJD2A to detect changes in glycolytic enzymes. We also evaluated the impacts of JMJD2A-lactate dehydrogenase A (LDHA) signaling on NPC cell proliferation, migration and invasion. ChIP assays were used to test whether JMJD2A bound to the LDHA promoter. Finally, IHC was used to verify JMJD2A and LDHA expression in NPC tissue samples and analyze their correlation between expression and clinical features. RESULTS: JMJD2A was expressed at high levels in NPC tumor tissues and cell lines. Both JMJD2A and LDHA expression were positively correlated with the tumor stage, metastasis and clinical stage. Additionally, the level of JMJD2A was positively correlated with LDHA expression in NPC patients, and higher JMJD2A and LDHA expression predicted a worse prognosis. JMJD2A alteration did not influence most of glycolytic enzymes expression, with the exception of PFK-L, PGAM-1, LDHB and LDHA, and LDHA exhibited the greatest decrease in expression. JMJD2A silencing decreased LDHA expression and the intracellular ATP level and increased LDH activity, lactate production and glucose utilization, while JMJD2A overexpression produced the opposite results. Furthermore, JMJD2A could combine to LDHA promoter region and regulate LDHA expression at the level of transcription. Activated JMJD2A-LDHA signaling pathway promoted NPC cell proliferation, migration and invasion. CONCLUSIONS: JMJD2A regulated aerobic glycolysis by regulating LDHA expression. Therefore, the novel JMJD2A-LDHA signaling pathway could contribute to the Warburg effects in NPC progression.


Asunto(s)
Carcinoma/genética , Carcinoma/metabolismo , Regulación Neoplásica de la Expresión Génica , Histona Demetilasas con Dominio de Jumonji/metabolismo , L-Lactato Deshidrogenasa/genética , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/metabolismo , Adenosina Trifosfato/metabolismo , Adulto , Anciano , Biomarcadores , Carcinoma/mortalidad , Carcinoma/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Progresión de la Enfermedad , Activación Enzimática , Femenino , Expresión Génica , Genes Reporteros , Glucosa/metabolismo , Glucólisis , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Estimación de Kaplan-Meier , L-Lactato Deshidrogenasa/metabolismo , Lactato Deshidrogenasa 5 , Ácido Láctico/metabolismo , Masculino , Persona de Mediana Edad , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/mortalidad , Neoplasias Nasofaríngeas/patología , Clasificación del Tumor , Estadificación de Neoplasias , Transducción de Señal , Transcripción Genética
11.
Photoacoustics ; 7: 12-19, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28649497

RESUMEN

Recent advances in atherosclerotic plaque detection have shown that not only does lipid core size and depth play important roles in plaque rupture and thrombi formation, but lipid composition, especially cholesterol deposition, is equally important in determining lesion vulnerability. Here, we demonstrate a spectral analysis assisted photoacoustic imaging approach to differentiate and map lipid compositions within an artery wall. The approach is based on the classification of spectral curves obtained from the sliding windows along time-of-flight photoacoustic signals via a numerical k-means clustering method. The evaluation result on a vessel-mimicking phantom containing cholesterol and olive oil shows accuracy and efficiency of this method, suggesting the potential to apply this approach in assessment of atherosclerotic plaques.

12.
Sci Rep ; 7(1): 1417, 2017 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-28469205

RESUMEN

Intravascular photoacoustic-ultrasound (IVPA-US) imaging is an emerging hybrid modality for the detection of lipid-laden plaques, as it provides simultaneous morphological and lipid-specific chemical information of an artery wall. Real-time imaging and display at video-rate speed are critical for clinical utility of the IVPA-US imaging technology. Here, we demonstrate a portable IVPA-US system capable of imaging at up to 25 frames per second in real-time display mode. This unprecedented imaging speed was achieved by concurrent innovations in excitation laser source, rotary joint assembly, 1 mm IVPA-US catheter size, differentiated A-line strategy, and real-time image processing and display algorithms. Spatial resolution, chemical specificity, and capability for imaging highly dynamic objects were evaluated by phantoms to characterize system performance. An imaging speed of 16 frames per second was determined to be adequate to suppress motion artifacts from cardiac pulsation for in vivo applications. The translational capability of this system for the detection of lipid-laden plaques was validated by ex vivo imaging of an atherosclerotic human coronary artery at 16 frames per second, which showed strong correlation to gold-standard histopathology. Thus, this high-speed IVPA-US imaging system presents significant advances in the translational intravascular and other endoscopic applications.


Asunto(s)
Estenosis Carotídea/diagnóstico por imagen , Técnicas Fotoacústicas/instrumentación , Técnicas Fotoacústicas/métodos , Ultrasonografía Intervencional/instrumentación , Adulto , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Placa Aterosclerótica/diagnóstico por imagen , Ultrasonografía Intervencional/métodos
13.
Artículo en Chino | MEDLINE | ID: mdl-27373038

RESUMEN

OBJECTIVE: To survey the prevalence of obstructive sleep apnea-hypopnea syndrome(OSAHS) in adults aged over 60 years in Dongying city,and analyze the risk factors and the extent of damage to the quality of life for the elderly to provide the basis for prevention and treatment of OSAHS people. METHOD: One thousand subjects were derived from a random cluster sampling in seven districts of Dongying city:they were asked to answer the questions from questionnaires. According to the questionnaire scoring, 100 subjects in high-risk group were selected randomly to make polysomnography monitoring for a whole night,so that the prevalence of the disease was calculated and the related risk factors were analyzed; elderly patients diagnosed with OSAHS were asked to assess the quality of life assessment questionnaire by face to face to understand the quality of life dimensions injury. RESULT: The actual number of completed surveys was 934, and the efficiency was 93.4%. The estimated prevalence of OSARS in elder people defined by apnea-hypopnea index (AHI ≥ 5) was 32.5%; Multivariate analysis revealed that age smoking, family snoring,neck circumference, waist circumference, and abnormality of the upper airway were respectively independent risk factors of OSAHS,and the abnormalities of the upper airway had the most obvious impact on AHI. The damage caused by OSAHS to the quality of life for elderly people followed their daily work life, social relationships, symptoms, alertness, emotional, general health, symptoms. CONCLUSION: The estimated prevalences of OSAHS in elder people were high. Actively promoting good habits to older people, weight loss, early detection and correct upper airway abnormalities may reduce the estimated prevalence of OSAHS. In the treatment process, the patient's physician should pay attention to their emotional and groom their psychological problems to improve the quality of life in elder people.


Asunto(s)
Apnea Obstructiva del Sueño/epidemiología , Anciano , China/epidemiología , Humanos , Polisomnografía , Prevalencia , Calidad de Vida , Factores de Riesgo , Ronquido , Encuestas y Cuestionarios
14.
Sci Rep ; 6: 25236, 2016 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-27121894

RESUMEN

A highly sensitive catheter probe is critical to catheter-based intravascular photoacoustic imaging. Here, we present a photoacoustic catheter probe design on the basis of collinear alignment of the incident optical wave and the photoacoustically generated sound wave within a miniature catheter housing for the first time. Such collinear catheter design with an outer diameter of 1.6 mm provided highly efficient overlap between optical and acoustic waves over an imaging depth of >6 mm in D2O medium. Intravascular photoacoustic imaging of lipid-laden atherosclerotic plaque and perivascular fat was demonstrated, where a lab-built 500 Hz optical parametric oscillator outputting nanosecond optical pulses at a wavelength of 1.7 µm was used for overtone excitation of C-H bonds. In addition to intravascular imaging, the presented catheter design will benefit other photoacoustic applications such as needle-based intramuscular imaging.


Asunto(s)
Estenosis Carotídea/diagnóstico por imagen , Técnicas Fotoacústicas/métodos , Dispositivos de Acceso Vascular , Humanos
15.
Biomed Opt Express ; 6(11): 4557-66, 2015 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26601018

RESUMEN

Lipid deposition inside the arterial wall is a hallmark of plaque vulnerability. Based on overtone absorption of C-H bonds, intravascular photoacoustic (IVPA) catheter is a promising technology for quantifying the amount of lipid and its spatial distribution inside the arterial wall. Thus far, the clinical translation of IVPA technology is limited by its slow imaging speed due to lack of a high-pulse-energy high-repetition-rate laser source for lipid-specific first overtone excitation at 1.7 µm. Here, we demonstrate a potassium titanyl phosphate (KTP)-based optical parametric oscillator with output pulse energy up to 2 mJ at a wavelength of 1724 nm and with a repetition rate of 500 Hz. Using this laser and a ring-shape transducer, IVPA imaging at speed of 1 frame per sec was demonstrated. Performance of the IVPA imaging system's resolution, sensitivity, and specificity were characterized by carbon fiber and a lipid-mimicking phantom. The clinical utility of this technology was further evaluated ex vivo in an excised atherosclerotic human femoral artery with comparison to histology.

16.
Nat Commun ; 6: 6767, 2015 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-25866015

RESUMEN

Photothermal interferometry is an ultra-sensitive spectroscopic means for trace chemical detection in gas- and liquid-phase materials. Previous photothermal interferometry systems used free-space optics and have limitations in efficiency of light-matter interaction, size and optical alignment, and integration into photonic circuits. Here we exploit photothermal-induced phase change in a gas-filled hollow-core photonic bandgap fibre, and demonstrate an all-fibre acetylene gas sensor with a noise equivalent concentration of 2 p.p.b. (2.3 × 10(-9) cm(-1) in absorption coefficient) and an unprecedented dynamic range of nearly six orders of magnitude. The realization of photothermal interferometry with low-cost near infrared semiconductor lasers and fibre-based technology allows a class of optical sensors with compact size, ultra sensitivity and selectivity, applicability to harsh environment, and capability for remote and multiplexed multi-point detection and distributed sensing.

17.
Opt Express ; 23(3): 2121-32, 2015 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-25836083

RESUMEN

A continuous wave (CW) quantum cascade laser (QCL) based absorption sensor system was demonstrated and developed for simultaneous detection of atmospheric nitrous oxide (N(2)O), methane (CH(4)), and water vapor (H(2)O). A 7.73-µm CW QCL with its wavelength scanned over a spectral range of 1296.9-1297.6 cm(-1) was used to simultaneously target three neighboring strong absorption lines, N(2)O at 1297.05 cm(-1), CH(4) at 1297.486 cm(-1), and H(2)O at 1297.184 cm(-1). An astigmatic multipass Herriott cell with a 76-m path length was utilized for laser based gas absorption spectroscopy at an optimum pressure of 100 Torr. Wavelength modulation and second harmonic detection was employed for data processing. Minimum detection limits (MDLs) of 1.7 ppb for N(2)O, 8.5 ppb for CH(4), and 11 ppm for H(2)O were achieved with a 2-s integration time for individual gas detection. This single QCL based multi-gas detection system possesses applications in environmental monitoring and breath analysis.

18.
Opt Express ; 22(20): 24894-907, 2014 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-25322061

RESUMEN

This paper investigates the effect of modal interference on the performance of hollow-core photonic bandgap fiber (HC-PBF) gas sensors. By optimizing mode launch, using proper length of sensing HC-PBF, and applying proper wavelength modulation in combination with lock-in detection, as well as appropriate digital signal processing, an estimated lower detection limit of less than 1 part-per-million by volume (ppmv) acetylene is achieved.

19.
Opt Express ; 22(11): 13190-201, 2014 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-24921514

RESUMEN

The response of the commercial HC-1550-02 hollow-core photonic bandgap fiber (HC-PBF) to gas pressure applied internally to the hollow-core was experimentally investigated. The transmission spectrum of the HC-PBF was hardly affected by the pressure, while the accumulated phase of the fundamental optical mode showed a normalized pressure sensitivity of 1.044 × 10(-2) rad/(Pa∙m), which is over two orders of magnitude higher than that to the external pressure. Numerical simulation showed that the observed high sensitivity to pressure is due to the pressure-induced refractive index change of air inside the hollow-core. This research could find potential applications in high sensitivity static and dynamic pressure measurement and optical phase manipulation.

20.
Opt Lett ; 38(4): 434-6, 2013 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-23455093

RESUMEN

We demonstrate a fiber-tip photoacoustic spectrometric sensor for trace gas detection. The sensor head is a miniature fiber-tip hollow-cavity with a deflectable polymer diaphragm. Periodic light absorption of gas molecules within the cavity generates an acoustic pressure wave, which causes deflection of the diaphragm. The hollow cavity also is a Fabry-Perot interferometer with which the diaphragm deflection is detected with high sensitivity. Experimental test around the P(9) absorption line of C(2)H(2) achieved a minimum detectable gas concentration of 4.3 ppm with an excitation laser power of 8 mW. The miniature sensor head and fiber optic detection system make this type of spectrometers ideally suited for remote and space-limited applications as well as for multipoint detection in a multiplexed fiber optic sensor network.

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