Demonstration of a near-IR line-referenced electro-optical laser frequency comb for precision radial velocity measurements in astronomy

An important technique for discovering and characterizing planets beyond our solar system relies upon measurement of weak Doppler shifts in the spectra of host stars induced by the influence of orbiting planets. A recent advance has been the introduction of optical frequency combs as frequency references. Frequency combs produce a series of equally spaced reference frequencies and they offer extreme accuracy and spectral grasp that can potentially revolutionize exoplanet detection. Here we demonstrate a laser frequency comb using an alternate comb generation method based on electro-optical modulation, with the comb centre wavelength stabilized to a molecular or atomic reference. In contrast to mode-locked combs, the line spacing is readily resolvable using typical astronomical grating spectrographs. Built using commercial off-the-shelf components, the instrument is relatively simple and reliable. Proof of concept experiments operated at near-infrared wavelengths were carried out at the NASA Infrared Telescope Facility and the Keck-II telescope.

Laser frequency combs emit a spectrum of equally spaced peaks that can provide precise frequency references useful for astronomy. Here, the authors demonstrate a frequency comb using electro-optical modulation, which has a line spacing that is resolvable using grating spectrographs unlike the mode-locking approach.

Long latency reflex response of superficial trunk musculature in athletes with chronic low back pain

BACKGROUND AND OBJECTIVES

Incidence of Low Back Pain (LBP) in athletes is as high as 30%. Patients with LBP show altered postural and neuromuscular responses to various functional tasks. The objective of the study was to compare long latency reflex response (occurring between 40 to ∼ 100 ms duration) in athletes with chronic LBP with asymptomatic athletes.

METHODS

Surface electromyography (EMG) of superficial trunk muscles - Rectus Abdominis (RA) and Erector Spinae (ES) were studied in athletes with chronic LBP (n=24) and asymptomatic athletes (n=25). Perturbations were introduced in standing both expectedly and unexpectedly. The latency of onset and the Root Mean Square (RMS) amplitudes within the reaction duration were compared between the two groups.

RESULTS

The latency of onset was delayed in Unexpected perturbations but no change was observed in Expected tasks. The mean RMS amplitudes were significantly lower in both tasks for RA and in the Expected task for ES (p< 0.05).

CONCLUSION

Chronic LBP athletes exhibit a delay in onset latency to Unexpected perturbations and reduced long latency response amplitudes to perturbation tasks compared to asymptomatic athletes. These changes could predispose athletes to recurrent low back pain and further injury.

Midurethral sling is the dominant procedure for female stress urinary incontinence: analysis of case logs from certifying American Urologists

OBJECTIVE

To investigate contemporary trends in the use of midurethral sling procedures for the surgical correction of female stress urinary incontinence over the past decade.

METHODS

Annualized case log data for female incontinence surgeries from certifying and recertifying urologists were obtained from the American Board of Urology. Descriptive analysis of the number and type of cases per year was performed. Associations between surgeon characteristics and the use of female incontinence procedures were evaluated.

RESULTS

A total of 6355 nonpediatric urologists applied for certification or recertification between 2003 and 2012. Two-thirds (4185) reported performing any procedures for female incontinence. Procedures sharply increased from 4632 in 2003 to 7548 in 2004, then remained relatively stable between 2005 and 2012 (range, 8014-10,238 cases). Traditional procedures decreased from 17% of female incontinence procedures in 2003 to 5% in 2004 to <1% since 2010 (P <.0005). Midurethral sling procedures have risen sharply from 3210 procedures in 2003 to 7200 in 2012 (P <.0005). Endoscopic injection treatments have remained stable.

CONCLUSION

Midurethral slings have been widely adopted by urologists over the last decade. Increase in sling usage coincided with a drastic decline in traditional repairs, implying that the newer midurethral slings were replacing these traditional procedures for the treatment of female incontinence. In addition, the fact that the use of periurethral injections did not change significantly during this time period indicates that increased sling usage is responsible for most of the decline in traditional repairs.

Isolated cavitary lung disease in a renal allograft recipient: A rare manifestation of cryptococcus

Although lungs are the portal of entry for cryptococcus, pulmonary disease is relatively uncommon. Cavitary pulmonary disease is even less common. We report a rare case of cryptococcosis with an isolated cavitary lung lesion in a renal allograft recipient.

Development of non-exercise based VO2max prediction equation in college-aged participants in India

AIM

The purpose of this study was to develop a linear regression model to predict treadmill VO2max scores using non-exercise data.

METHODS

In this cross sectional study, one hundred twenty college-aged participants (60 male, 60 female, mean age 22.02±2.29 years) voluntarily participated and successfully completed a maximal graded exercise test (GXT) on a motorized treadmill to assess VO2max (mean±SD; 2.05 L·min-¹±1.03 L·min-¹). The maximal treadmill GXT required participants to exercise to volitional fatigue.

RESULTS

Relevant non-exercise data included a mean (±SD) perceived functional ability (PFA) score, and physical activity rating (PA-R) score, body surface area (BSA) of 14.6±3.9, 2.97±1..75, 1.66±0.17, respectively. Multiple linear regression generated the following regression equation (R=0.899, R2=0.805, adjusted R2=0.799, SEE=0.426 L·min-¹): VO2max (L/min)=-1.541+1.096 (gender, 1=male, 0=female) +.081 (PFA) +1.084(BSA). Each predictor variable was statistically significant (P<0.05) with beta weights for gender, PFA, BSA, PA-R, and equal to (-0.518), (0.255), (0.228), (0.092), percent body fat (-0.003), respectively. The accuracy of the model was evaluated by conducting a cross-validation analysis (N.=18).

CONCLUSION

This study provides a N-EX regression prediction model that yields results and also provide a convenient and efficient tool that estimate VO2max in healthy college-aged participants in India.

Evaluation of a modified arthritis self-efficacy scale for an ankylosing spondylitis UK population

OBJECTIVES

To evaluate an Ankylosing Spondylitis-specific Arthritis Self-Efficacy Scale (ASES-AS) United Kingdom (UK) secondary care population.

METHODS

The ASES-AS is based on the 8-item ASES with minor alterations in phraseology. Patients from ten secondary care rheumatology centres across England were asked to complete a postal questionnaire concerning sociodemographic and clinical characteristics: Bath AS Functional Index (BASFI), Bath AS Disease Activity Index (BASDAI), numerical pain rating scale (NRS), Hospital Anxiety and Depression Scale (HADS), Short Form 36 (SF-36), Evaluation of AS Quality of Life questionnaire (EASi-QoL) and ASES-AS. Respondents received repeat questionnaires at 2 weeks and 6 months including health transition questions assessing change in AS-specific and general health. The ASES-AS was assessed for data quality, reliability, validity, and responsiveness.

RESULTS

Response rate was 64% (n=612), 72% (n=438) were male, mean age 50.8yrs (SD 12.2 yrs), mean disease duration 17.3 yrs (SD 11.7 yrs) and mean symptom duration 22.4 yrs (SD 12.4 yrs). Missing data for each item/total score range was 0.7%-3.1%. Item-total correlations range was 0.66 to 0.83. Cronbach's alpha was 0.93 and test-retest reliability (intraclass correlation coefficient) 0.77. A priori hypothesised associations between ASAS-AS and disease status measures were supported. Social variables potentially related to self-efficacy demonstrated evidence of convergent validity (employment p<0.001, educational level p<0.005). A Modified Standard Response Mean (MSRM) of 0.44 and 0.26 in AS-specific and general health respectively at 6 months indicates moderate responsiveness.

CONCLUSIONS

ASES-AS has good evidence supporting its application as an AS-specific self-efficacy measure in research including clinical trials at a group level.

Effectiveness of walking with pedometer and heart rate monitor on the quality of life and wellbeing in Asian Indians with type 2 diabetes

Introduction: The objective of the study was to analyze the effect of an eight week walking program using a pedometer and heart rate monitor (HRM) for evaluating exercise intensity compared with walking alone on quality of life and general wellbeing (GWB) in Asian Indians with type 2 diabetes.

Methods: Forty adults with type 2 diabetes were randomly assigned to an eight week supervised program of walking alone (group A) and walking using pedometer and HRM (group B). A suitably designed and validated questionnaire was administered before and after eight weeks of training for all patients to assess the quality of life (ADDQoL-19) and general wellbeing (W-BQ12).

Results: At the end of the study, quality of life and general wellbeing scores were found markedly improved in both the groups. In group A, a statistically significant reduction was noted for seven items and in group B a statistically significant reduction was seen in eleven items of the quality of life questionnaire.

General wellbeing scores were improved in both groups by 26.2% in group A and 28.8% in group B (P<0.05).

Conclusion: Walking using a pedometer and heart rate monitor for assessing exercise intensity and motivation was found more effective than walking alone in improving quality of life and general wellbeing for Asian Indians with type 2 diabetes.

Full-field acoustomammography using an acousto-optic sensor

In this Letter the authors introduce a wide-field transmission ultrasound approach to breast imaging based on the use of a large area acousto-optic (AO) sensor. Accompanied by a suitable acoustic source, such a detector could be mounted on a traditional mammography system and provide a mammographylike ultrasound projection image of the compressed breast in registration with the x-ray mammogram. The authors call the approach acoustography. The hope is that this additional information could improve the sensitivity and specificity of screening mammography. The AO sensor converts ultrasound directly into a visual image by virtue of the acousto-optic effect of the liquid crystal layer contained in the AO sensor. The image is captured with a digital video camera for processing, analysis, and storage. In this Letter, the authors perform a geometrical resolution analysis and also present images of a multimodality breast phantom imaged with both mammography and acoustography to demonstrate the feasibility of the approach. The geometric resolution analysis suggests that the technique could readily detect tumors of diameter of 3 mm using 8.5 MHz ultrasound, with smaller tumors detectable with higher frequency ultrasound, though depth penetration might then become a limiting factor. The preliminary phantom images show high contrast and compare favorably to digital mammograms of the same phantom. The authors have introduced and established, through phantom imaging, the feasibility of a full-field transmission ultrasound detector for breast imaging based on the use of a large area AO sensor. Of course variations in attenuation of connective, glandular, and fatty tissues will lead to images with more cluttered anatomical background than those of the phantom imaged here. Acoustic coupling to the mammographically compressed breast, particularly at the margins, will also have to be addressed.

Plasma Homocysteine and Insulin in Diabetic Nephropathy: Relationship to Body Mass Index

The data on plasma homocysteine and endogenous insulin in type 2 diabetes mellitus with nephropathy and relationship to body mass index (BMI) is particularly from the Indian subcontinent. A prospective study was carried out in 50 patients of type 2 diabetes mellitus with overt nephropathy (Group A). The results were compared with 25 diabetics without nephropathy (Group B), and 25 age and sex matched healthy controls (Group C). Microenzyme immunoassay and ELISA estimated the plasma homocysteine and insulin, respectively. The mean values of plasma homocysteine were significantly elevated in diabetic nephropathy (21.3+/-7.2 micromol/L) and diabetics without nephropathy (19.4+/-7.1) when compared to healthy control (11.5+/-2.3). The insulin levels and BMI were significantly higher in diabetics as compared to controls. There was no correlation between homocysteine and insulin, homocysteine and BMI, and homocysteine with the degree of renal failure.

Hemodynamic Effects of Arteriovenous Fistula in End‐Stage Renal Failure

Hemodynamic parameters using Swan Ganz catheter were studied in 17 patients with end stage renal disease. The acute effects of radiocephalic AV fistula on the hemodynamic parameters were studied at 24 hours of surgery. The chronic effects were studied in 8 of these patients at 6 weeks of arteriovenous (AV) fistula. The AV fistula matured in 3 to 4 weeks time and blood flow was sufficient for hemodialysis (400 mL/min). Patients with chronic renal failure had normal or high normal hemodynamic parameters. Six weeks after the AV fistula, the cardiac index and the stroke volume index slightly increased along with a significant increase in systolic and mean systemic arterial pressure. None of the patients had significant increase in cardiac filling pressures. Although there was some fall in systemic vascular resistance index and rise in cardiac index and stroke volume index, these changes were physically small and unlikely to put any extra hemodynamic load. Thus, AV fistula in dialysis patients is not an appreciable cause of circulatory or pulmonary congestion.

Effects of resistance training on metabolic profile of adults with type 2 diabetes

BACKGROUND & OBJECTIVE

The number of diabetes in India is increasing at an alarming rate. The effects of physical activity in the form of resistance training or aerobic exercises on type 2 diabetes have not been studied in Indian population. The objective of this study was to analyse the effects of eight weeks of progressive resistance training (PRT) compared with aerobic exercise (AE) on glycaemic control, metabolic profile, cardiovascular fitness parameters and general well being in adults with type 2 diabetes.

METHODS

Thirty adults (14 females and 16 males mean; age 53.8 +/- 8.8 yr) with type 2 diabetes were randomly assigned to 8 wk supervised PRT (n=10) or AE (n=10) or control group (n=10). Glycosylated haemoglobin (HbA1c), lipid profile, blood pressure, heart rate, body mass index (BMI) and general well being were measured before training (i.e. 0 wk) and after 8 wk of training period.

RESULTS

Plasma glycosylated haemoglobin levels decreased significantly (P<0.05) both in the PRT group (7.57 +/- 2.4% to 6.23 +/- 0.8%) and in AE group (8.11+/-0.9% to 6.66 +/- 0.9%).Total cholesterol levels decreased significantly (P<0.05) by 13.3 per cent in PRT group and by 6.1 per cent in AE group. Both exercise groups showed significantly reduction in systolic blood pressure (P<0.05). General well being improvement was much more in PRT (8.6%) as compared to AE group (2.7%).

INTERPRETATION & CONCLUSION

Our findings showed that both PRT and AE were effective in improving metabolic profile of adults with type 2 diabetes but the percentage improvement in triglycerides, total cholesterol levels and general well being with PRT was more compared to AE. Further studies on a larger sample need to be done to confirm these findings.