Common-path multimodal optical microscopy

We have developed a common-path multimodal optical microscopy system that is capable of using a single optical source and a single camera to image amplitude, phase, and fluorescence features of a biological specimen. This is achieved by varying either contrast enhancement filters at the Fourier plane and/or neutral density/fluorescence filters in front of the CCD camera. The feasibility of the technique is demonstrated by obtaining brightfield, fluorescence, phase-contrast, spatially filtered, brightfield + fluorescence, phase +fluorescence, and edge-enhanced+fluorescence images of the same Drosophila embryo without the need for image registration and fusion. This comprehensive microscope has the capability of providing both structural and functional information and may be used for applications such as studying live-cell dynamics and in high throughput microscopy and automated microscopy

Range safety signal propagation through the SRM exhaust plume of the space shuttle

Theoretical predictions of plume interference for the space shuttle range safety system by solid rocket booster exhaust plumes are reported. The signal propagation was calculated using a split operator technique based upon the Fresnel-Kirchoff integral, using fast Fourier transforms to evaluate the convolution and treating the plume as a series of absorbing and phase-changing screens. Talanov's lens transformation was applied to reduce aliasing problems caused by ray divergence

Nonlinear photoacoustics for measuring the nonlinear optical absorption coefficient

We report a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. The sample is scanned through the focused laser beam and the generated photoacoustic signal is recorded using a 10 MHz focused ultrasound transducer. Since the signal strength is directly proportional to the optical absorption, PAZ-scan displays nonlinear behavior depicting the nonlinear optical absorption of the material. Among many advantages, our experiments on mouse blood show that PAZ-scan can potentially be used as a standard technique to calibrate contrast agents used in theranostics in general and photoacoustics in particular

Plume RF interference calculations for space shuttle

During a static ground test of a full-scale SRM, measurements of attenuation of the UHF 416.5 MHz Range Safety Signal, the VHF voice link (230 MHz), and of S-band (c. 2.2. GHz) communications links were undertaken. Analyses of these results indicate that measurable attenuation did occur at all test frequencies. The measured attenuation levels are compared with a simple model in which the received signal is identified as that diffracted about the edge of the highly absorbing plume and the signal level in the shadow zone is evaluated using the formula for diffraction at a straight edge. The comparison is satisfactory at VHF and UHF frequencies, and slightly less so at S-band. Reasons for the discrepancies found at higher frequencies are discussed. A revised procedure which appears to relieve the accuracy problem was developed. This procedure is discussed along with applications to high altitude SRM plume attenuation

Histopathological prognostic factor comparison of endometrial cancer patients in a tertiary hospital in India

Background: The objective of this study was to describe the histopathological features of patients with endometrial cancer in a tertiary hospital in South India.Methods: This retrospective study included cases diagnosed and operated in a tertiary hospital in the period of 3 years. Histopathological data was retrieved from records and analyzed. The study included both endometrial biopsy and post hysterectomy specimens of which prognostic factor comparison was performed on the latter following TNM and FIGO staging systems.Results: The sample consisted of 43 patients which includes 28 resected and 15 biopsy specimens. Age ranged from a minimum of 27 years to a maximum of 75 years (Mean around 52 years). Endometrioid adenocarcinoma was the predominant histological subtype (80 – 85%), while other types included papillary serous adenocarcinoma, stromal sarcoma and malignant mixed mullerian tumour (MMMST). Grade I tumours were 19 in number constituting 79.16% and stage IB tumours were the commonest. Pelvic nodal involvement, lymphatic invasion and recurrence were individually noted in one patient each.Conclusions: This study highlights the prognostic characteristics of endometrial cancer patients with most of them presenting in early stages thereby having a good prognostic outcome

Medical image processing using transient Fourier holography in bacteriorhodopsin films

Real time image processing is demonstrated by recording and reconstructing the transient photoisomerizative grating formed in the bR film using Fourier holography. Desired spatial frequencies including both high and low band in the object beam are reconstructed by controlling the reference beam intensity. The results are in agreement with a theoretical model based on photoisomerization grating. We exploit this technique to process mammograms in real-time for identification of microcalcifications buried in the soft tissue for early detection of breast cancer. A feature of the technique is the ability to transient display of selected spatial frequencies in the reconstructing process which enables the radiologists to study the features of interest

High sensitivity C-reactive protein levels across spectrum and severity of coronary artery disease

Background: C-reactive protein (CRP) is an acute-phase reactant protein synthesized by the liver in response to acute\ud stress in a wide range of acute and chronic inflammatory conditions. In healthy subjects and patients presenting with\ud coronary artery disease (CAD), elevated levels of CRP has repeatedly been demonstrated to predict future cardiovascular\ud events.\ud Methods: We measured high sensitivity C-reactive protein (hs-CRP) levels in 382 consecutive patients with CAD and 60 healthy controls by immunoturbidimetry method. Risk factors like hypertension, diabetes mellitus, dyslipidaemia,smoking, obesity and family history of premature CAD were assessed.\ud Results: The mean age of patients with CAD was 53.5±11.8 years (303 males) and that of control group was 50.83±8.07(28 males). The patient group had significant higher concentration of mean hs-CRP levels when compared\ud with the healthy control group (1.8±1.9 mg/L vs 0.35±1.1 mg/L, p<0.001). The mean hs-CRP levels of unstable angina\ud (USA) and myocardial infarction (MI) patients was higher than chronic stable angina (CSA) patients (p<0.05). Based\ud on the disease severity, we found a significantly higher hs-CRP levels in patients of triple vessel disease when compared\ud to patients with single vessel disease (p=0.01).\ud Conclusions: Elevated serum hs-CRP levels provide a useful marker for cardiovascular risk which, when combined\ud with traditional risk factors, may help improve global risk prediction. Our study showed a significant contribution of\ud hs-CRP to coronary risk prediction with better discrimination