Trace-gas detection in ambient air with a thermoelectrically cooled, pulsed quantum-cascade distributed feedback laser.

A pulsed quantum-cascade distributed feedback laser operating at near room temperature was used for sensitive high-resolution IR absorption spectroscopy of ambient air at a wavelength of approximately 8 microm. Near-transform-limited laser pulses were obtained owing to short (approximately 5-ns) current pulse excitation and optimized electrical coupling. Fast and slow computer-controlled frequency scanning techniques were implemented and characterized.

Psychiatric disorders, HIV infection and HIV/hepatitis co-infection in the correctional setting.

Psychiatric disorders such as bipolar disorder, schizophrenia and depression have long been associated with risk behaviors for HIV, hepatitis C virus (HCV) and hepatitis B virus (HBV). The US prison population is reported to have elevated rates of HIV, hepatitis and most psychiatric disorders. This study examined the association of six major psychiatric disorders with HIV mono-infection, HIV/HCV co-infection and HIV/HBV co-infection in one of the nation's largest prison populations.

Impaired plasma nonesterified fatty acid tolerance is an early defect in the natural history of type 2 diabetes.

Context: Abnormal plasma nonesterified fatty acid (NEFA) metabolism may play a role in the development of type 2 diabetes.

Objectives: Our objectives were to demonstrate whether there is a defect in insulin-mediated suppression of plasma NEFA appearance (RaNEFA) and oxidation (OxNEFA) during enhanced intravascular triacylglycerol lipolysis early in the natural history of type 2 diabetes, and if so, to determine whether other mechanisms than reduced insulin-mediated suppression of intracellular lipolysis are involved.

Design: These are cross-sectional studies.

High-resolution (Doppler-limited) spectroscopy using quantum-cascade distributed-feedback lasers.

Lasing characteristics were evaluated for distributed-feedback quantum-cascade (QC) lasers operating in a continuous mode at cryogenic temperatures. These tests were performed to determine the QC lasers' suitability for use in high-resolution spectroscopic applications, including Doppler-limited molecular absorption and pressure-limited lidar applications. By use of a rapid-scan technique, direct absorbance measurements of nitric oxide (NO) and ammonia (NH>(3)) were performed with several QC lasers, operating at either 5.

Association of polymorphisms in TGFB1 and prostate cancer prognosis.

Purpose: Because of the role of TGFB1 in prostate cancer and progression, we hypothesized that polymorphisms of TGFB1 at C-509T may be associated with prostate cancer risk and/or more aggressive tumors.

Materials And Methods: This is a case-control study. Controls consisted of male volunteers 40 years old or older with a normal digital rectal examination and prostate specific antigen 2.

Kilohertz linewidth from frequency-stabilized mid-infrared quantum cascade lasers.

Frequency stabilization of mid-IR quantum cascade (QC) lasers to the kilohertz level has been accomplished by use of electronic servo techniques. With this active feedback, an 8.5-microm QC distributed-feedback laser is locked to the side of a rovibrational resonance of nitrous oxide (N(2) O) at 1176.

Photoacoustic spectroscopy using quantum-cascade lasers.

Photoacoustic spectra of ammonia and water vapor were recorded by use of a continuous-wave quantum-cascade distributed-feedback (QC-DFB) laser at 8.5 mum with a 16-mW power output. The gases were flowed through a cell that was resonant at 1.

Quantitative gas sensing by backscatter-absorption measurements of a pseudorandom code modulated lambda ~ 8-microm quantum cascade laser.

We have demonstrated quantitative chemical vapor detection with a multimode quantum cascade (QC) laser. Experiments incorporated pseudorandom code (PRC) modulation of the laser intensity to permit sensitive absorption measurements of isopropanol vapor at 8.0micro .

Children's Oncology Group (COG) Nutrition Committee.

The Children's Oncology Group (COG) Nutrition Committee was established to further the knowledge of nutrition in children with cancer by education and the conduct of clinical trials. A survey of COG institutions revealed lack of conformity in evaluation and categorization of nutritional status, and criteria for nutritional intervention. The Committee subsequently established specific categories of malnutrition (Underweight and Overweight) based on ideal body weight or body mass index.

Cavity ringdown spectroscopy using mid-infrared quantum-cascade lasers.

Cavity ringdown spectra of ammonia at 10 parts in 10(9) by volume (ppbv) and higher concentrations were recorded by use of a 16-mW continuous-wave quantum-casacde distributed-feedback laser at 8.5 mum whose wavelength was continuously temperature tuned over 15 nm. A sensitivity (noise-equivalent absorbance) of 3.

High-power, continuous-wave, current-tunable, single-mode quantum-cascade distributed-feedback lasers at lambda - 5.2 and lambda - 7.95 mum.

Quantum-cascade distributed-feedback lasers with high-power, continuous-wave (cw), tunable, single-mode emission are reported. The emission wavelengths are near 5.2 and 7.

Kolmogorov-Arnold-Moser transition and laser action on scar modes in semiconductor diode lasers with deformed resonators.

Measurements of the optical spectra of semiconductor injection lasers with deformed cylinder resonators show strong indications of the classical Kolmogorov-Arnold-Moser transition from integrability to chaos for devices with small deformation. At larger deformation, evidence for laser action on scar modes is obtained. The diode lasers operate with TE polarization, resulting in laser action on (partially) chaotic whispering-gallery modes for all deformations.

Generation of tunable far-infrared radiation with a quantum cascade laser.

We demonstrate the generation of cw tunable far-infrared radiation by mixing a quantum cascade laser and a CO>(2) laser in a W-Ni metal-insulator-metal diode. The first known spectroscopic application to the recording of an H(79)Br transition near 4.47 THz is reported.

Free-running frequency stability of mid-infrared quantum cascade lasers.

The intrinsic frequency fluctuations of two single-mode quantum cascade (QC) distributed-feedback lasers operating continuously at a wavelength of 8.5 mum are reported. A Doppler-limited rovibrational resonance of nitrous oxide is used to transform the frequency noise into measurable intensity fluctuations.

Adiposity, the metabolic syndrome, and breast cancer in African-American and white American women.

Breast cancer, the second most common cause of cancer-related deaths in American women, varies substantially in incidence and mortality according to race and ethnicity in the United States. Although the overall incidence of breast cancer among African-American (AA) women is lower than in white American women, this cancer is more common in young premenopausal AA women, and AA breast cancer patients of all ages are more likely to have advanced disease at diagnosis, higher risk of recurrence, and poorer overall prognosis. Epidemiological studies indicate that these differences may be attributable in part to variation in obesity and body fat distribution.

Myo-inositol in patients with polycystic ovary syndrome: a novel method for ovulation induction.

Background: Polycystic ovary syndrome (PCOS) is often characterized by chronic oligo- or anovulation (usually manifested as oligo- or amenorrhea), and hyperandrogenism. In addition, 30-40% of PCOS women have impaired glucose tolerance, and a defect in the insulin signaling pathway (inositol-containing phosphoglycan mediators) seems to be implicated in the pathogenesis of insulin resistance. PCOS patients are subfertile as a consequence of such ovulatory disorders and often need drugs, such as clomiphene citrate or follicle-stimulating hormone, for ovulation induction, which increases the risk of multiple pregnancy and ovarian hyperstimulation syndrome.

Assessment of 54 biomarkers for biopsy-detectable prostate cancer.

Objective: We analyzed the association of 54 biomarkers from seven classes including adipokines, immune response metalloproteinases, adhesion molecules, and growth factors with prostate cancer risk adjusting for the Prostate Cancer Prevention Trial (PCPT) risk score.

Methods: A total of 123 incident prostate cancer cases and 127 age-matched controls were selected from subjects in the San Antonio Center for Biomarkers of Risk of Prostate Cancer cohort study. Prediagnostic serum concentrations were measured in the sample collected at baseline using LabMAP technology.

Integrated obesity care management system -implementation and research protocol.

Background: Nearly 50% of Canadians are overweight and their number is increasing rapidly. The majority of obese subjects are treated by primary care physicians (PCPs) who often feel uncomfortable with the management of obesity. The current research proposal is aimed at the development and implementation of an innovative, integrated, interdisciplinary obesity care management system involving both primary and secondary care professionals.

Adrenocortical dysregulation as a major player in insulin resistance and onset of obesity.

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome.

Brothers of women with polycystic ovary syndrome are characterised by impaired glucose tolerance, reduced insulin sensitivity and related metabolic defects.

Aims/hypothesis: Since it has been shown that polycystic ovary syndrome (PCOS) is highly inherited and characterised by insulin resistance, we hypothesised that male siblings of PCOS women would also be insulin resistant. Thus, our aim was to assess insulin sensitivity and metabolic parameters in brothers of women with PCOS and male control individuals.

Methods: Seventeen brothers of PCOS women and 28 male control volunteers were assessed with 75 g OGTTs and euglycaemic-hyperinsulinaemic clamps.

End-stage liver disease in a state prison population.

Objectives: Information on the epidemiology of end-stage liver disease (ESLD) in US correctional populations is limited. We examined the prevalence, mortality and clinical characteristics of ESLD in the nation's second largest state prison system.

Methods: We collected and analyzed medical and demographic data from 370,511 offenders incarcerated in Texas' prison system during a 3.

Role of insulin in the hyperandrogenemia of lean women with polycystic ovary syndrome and normal insulin sensitivity.

Objective: To determine the effect of reducing insulin secretion on hyperandrogenemia in lean normoinsulinemic women with polycystic ovary syndrome (PCOS) and normal metabolic insulin sensitivity.

Design: Transversal assessment at baseline and prospective follow-up of lean PCOS group after 8 days of diazoxide, which reduces insulin secretion, and 1 month of leuprolide, which suppresses LH.

Setting: Clinical research center of an academic hospital.

National survey of pediatric residency program directors and residents regarding education in palliative medicine and end-of-life care.

Purpose: To determine how palliative and end-of-life care can best be incorporated into the training of pediatric residents.

Methods: From 2001 to 2002, we surveyed 246 directors and 235 residents of pediatric residency programs. We elicited responses regarding (1) perceived relevance of pediatric palliative care, (2) residents' exposure to palliative medicine, (3) competency of faculty and matriculating residents in palliative care, (4) core palliative medicine competencies, and (5) the best teaching/learning format for palliative care.

Suitability of recommended limits for fasting glucose tests in women with polycystic ovary syndrome.

Background: The Canadian and American Diabetes Associations recommend the use of an oral glucose tolerance test to screen for abnormal glucose tolerance among women with polycystic ovary syndrome when their fasting plasma glucose level is 5.7 mmol/L or more (Canadian guideline) and 5.6 mmol/L or more (American).