Portal Imaging Using a CSI (TL) Scintillator Coupled to a Cooled CCD Camera

The purpose of this research was to design a high performance digital portal imaging system, using a transparent x-ray scintillator coupled to a cooled CCD camera. Theoretical analysis using Monte Carlo simulation was performed to calculate the QDE, SNR and DQE of the system. A prototype electronic portal imaging device (EPID) was built, using a 12.7 mm thick, 20.32 cm diameter, CsI (Tl) scintillator, coupled to an Astromed ® liquid nitrogen cooled CCD TV camera. The system geometry of the prototype EPID was optimized to achieve high spatial resolution. Experimental evaluation of the prototype EPID was performed, by determining its spatial resolution, contrast resolution, depth of focus and light scatter. Images of phantoms, animals and human subjects were acquired using the prototype EPID and were compared with those obtained using conventional and high contrast portal film and a commercial EPID. An image processing protocol was developed. The protocol was comprised of preprocessing, noise removal and image enhancement algorithms. An adaptive median filter algorithm for the removal of impulse noise was developed, analyzed and incorporated into the image processing protocol. Results from the theoretical analysis and experimental evaluation have indicated that the performance of the CsI (Tl) - CCD system is comparable or superior to that of current commercial and experimental portal imaging technologies, such as high contrast portal film, commercial TV camera based EPIDs, and amorphous silicon based flat panel EPIDs

Strong A1\mathbb A^1-invariance of A1\mathbb A^1-connected components of reductive algebraic groups

We show that the sheaf of $\mathbb A^1$-connected components of a reductive algebraic group over a perfect field is strongly $\mathbb A^1$-invariant. As a consequence, torsors under such groups give rise to $\mathbb A^1$-fiber sequences. We also show that sections of $\mathbb A^1$-connected components of anisotropic, semisimple, simply connected algebraic groups over an arbitrary field agree with their $R$-equivalence classes, thereby removing the perfectness assumption in the previously known results about the characterization of isotropy in terms of affine homotopy invariance of Nisnevich locally trivial torsors.Comment: 14 pages, comments are welcome, v3: minor changes, results are unchange

Slit design for efficient and accurate MTF measurement at megavoltage xâ ray energies

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135139/1/mp7405.pd

DEVELOPEMENT AND VALIDATION OF ANALYTICAL METHOD FOR SIMULTANEOUS ESTIMATION OF CILNIDIPINE AND OLMESARTAN MEDOXOMIL IN BULK AND TABLET DOSAGE FORM BY RP-HPLC

An economical, precise, rapid and accurate RP HPLC method has been developed for the simultaneous estimation of Olmesartan Medoxomil and Cilnidipine in bulk and tablet dosage form. Separation was carried out on Jasco HPLC system equipped with HiQ sil C18 column (250 × 4.6 mm i.d.) and PDA detector using Methanol: 40 mM Potassium dihydrogen ortho phosphate buffer (90:10 v/v) as the mobile phase.Ortho-phosphoric acid was used to adjust pH to 3.0, and detection was carried out at 254 nm. Results were linear in the range of 5-30 μg/ml for Cilnidipine and 10-50 μg/ml for Olmesartan Medoxomil respectively. The method was successfully applied for the analysis of drugs in pharmaceutical formulation. Results of the analysis were validated statistically and by recovery studies

Evaluation of losartan plus hydrochlorothiazide combination therapy against amlodipine monotherapy in patients of hypertension

Background: Microalbuminuria has been shown to predict cardiovascular disease (CVD) in patients with hypertension. Recently the FDC of losartan and hydrochlorothiazide (HCTZ) has been reported to be effective for achieving a target BP level and also improvement in cardiovascular prognosis. The present study was conducted to compare effect of losartan plus hydrochlorothiazide combination therapy and high dose amlodipine monotherapy on blood pressure and microalbuminuria.Methods: Total 184 patients with hypertension were randomly allocated to two groups. The patients in group 1 received Amlodipine 5 mg orally for first 4 weeks. The  patients  from  group  2  received  losartan  50  mg  orally  for  first  4  weeks. Patients  in  group  1  were  titrated  to  amlodipine  10  mg  orally  for next 4 weeks. The patients in group 2 were titrated to FDC of losartan (50 mg) plus HCTZ (12.5 mg) for next 4 weeks. Follow–up visits were scheduled at 4 weeks and 8 weeks. Pulse rate, sSBP and sDBP were estimated at each follow–up. Microalbuminuria was estimated at 8 weeks.Results: There was no significant difference in mean change in sSBP, sDBP and pulse rate between two treatment groups (p>0.05). There was greater reduction in microalbuminuria in group 2 patients (p<0.0001). The adverse effects such as flushing and lower extremity oedema were significantly more in amlodipine group (p<0.05).Conclusions: Losartan plus HCTZ has similar effect on BP, better safety profile and superior effect on microalbuminuria level  reduction

On a computational approach for the approximate dynamics of averaged variables in nonlinear ODE systems: toward the derivation of constitutive laws of the rate type

A non-perturbative approach to the time-averaging of nonlinear, autonomous ODE systems is developed based on invariant manifold methodology. The method is implemented computationally and applied to model problems arising in the mechanics of solids.Comment: 34 pages PD