Cost-benefit modelling for reliability growth

Decisions during the reliability growth development process of engineering equipment involve trade-offs between cost and risk. However slight, there exists a chance an item of equipment will not function as planned during its specified life. Consequently the producer can incur a financial penalty. To date, reliability growth research has focussed on the development of models to estimate the rate of failure from test data. Such models are used to support decisions about the effectiveness of options to improve reliability. The extension of reliability growth models to incorporate financial costs associated with 'unreliability' is much neglected. In this paper, we extend a Bayesian reliability growth model to include cost analysis. The rationale of the stochastic process underpinning the growth model and the cost structures are described. The ways in which this model can be used to support cost-benefit analysis during product development are discussed and illustrated through a simple case

Fresnel zone plate telescopes for X-ray imaging II: numerical simulations with parallel and diverging beams

We present the results of simulations of shadows cast by a zone plate telescope which may have one to four pairs of zone plates. From the shadows we reconstruct the images under various circumstances. We discuss physical basis of the resolution of the telescope and demonstrate this by our simulations. We allow the source to be at a finite distance (diverging beam) as well as at an infinite distance (parallel beam) and show that the resolution is worsened when the source is nearby. By reconstructing the zone plates in a way that both the zone plates subtend the same solid angles at the source, we obtain back high resolution even for sources at a finite distance. We present simulated results for the observation of the galactic center and show that the sources of varying intensities may be reconstructed with accuracy. Results of these simulations would be of immense use in interpreting the X-ray images from recently launched CORONAS-PHOTON satellite.Comment: 17 pages, 36 figures, Published in Experimental Astronom

Role of biomarkers in predicting anastomotic leakage following colorectal surgeries

Background: Recovery after surgery for patients with colorectal disease has improved with the advent of minimal access surgery and standardized recovery protocols. Despite these advances, anastomotic leakage remains one of the most dreaded complications following colorectal surgery, with rates of 3-27 per cent depending on specific risk factors. The aim of the study was to assess sensitivity and specificity of systemic and peritoneal drain-fluid bio-markers in early prediction of anastomotic leak; and to co-relate rise in levels of biomarkers and severity of clinical symptoms in patients who have undergone colo-rectal surgeries.Methods: The present study was a prospective observational study conducted on 60 patients in the Postgraduate Department of Surgery, Government Medical College, Srinagar after obtaining due ethical clearance over a period of two years.Results: The mean age was 54.87±11.901 years with 44 patients (73.3%) were males. Among systemic makers: the mean CRP level was 2.7800±0.500 mg/L, the mean total leukocyte count was 10.783±0.940 thousands and the mean serum procalcitonin level was 0.365±0.1385 ng/ml. Among peritoneal fluid drain bio-makers, the mean IL-6 level was 3551.066±1311.965 pg/ml, the mean IL-10 level was 628.533±460.358 pg/ml and the mean TNF-a level was 16.391±6.736 pg/ml. The anastomotic leak after colo-rectal surgery was noted in 16 patients (26.7%). In our study significant co-relation was noted between the rise in levels of peritoneal drain fluid biomarkers and severity of clinical symptoms but no significant co-relation was noted between the rise in levels of systemic markers and severity of clinical symptoms in patients who have undergone colo-rectal surgeries.Conclusions: Systemic biomarkers are poor predictors of anastomotic leak after colorectal surgery. But sensitivity and specificity of peritoneal fluid drain biomarkers in predicting anastomotic leak was significantly high

Pathophysiology of Gallstones

Gallstones are the stones developing in the gallbladder. Evolution of pathophysiology changes the trends of treatment of a disease. Laparoscopic revolution was only because of gallstones diseases. The shifting of food habits increased the incidence of diseases in developing countries. There are mainly three types of stones Cholesterol, pigment and brown stones. The pathophysiology of which is different for each type. Cholesterol stones being most common owing to the risk factors being prevalent in the developing and developed societies. Pigment stones being most common in blood disorder patients while brown stones are most common in common bile duct and are infected ones

Evaluating Drug Prices, Availability, Affordability, and Price Components: Implications for Access to Drugs in Malaysia

BACKGROUND: Malaysia's stable health care system is facing challenges with increasing medicine costs. To investigate these issues a survey was carried out to evaluate medicine prices, availability, affordability, and the structure of price components. METHODS AND FINDINGS: The methodology developed by the World Health Organization (WHO) and Health Action International (HAI) was used. Price and availability data for 48 medicines was collected from 20 public sector facilities, 32 private sector retail pharmacies and 20 dispensing doctors in four geographical regions of West Malaysia. Medicine prices were compared with international reference prices (IRPs) to obtain a median price ratio. The daily wage of the lowest paid unskilled government worker was used to gauge the affordability of medicines. Price component data were collected throughout the supply chain, and markups, taxes, and other distribution costs were identified. In private pharmacies, innovator brand (IB) prices were 16 times higher than the IRPs, while generics were 6.6 times higher. In dispensing doctor clinics, the figures were 15 times higher for innovator brands and 7.5 for generics. Dispensing doctors applied high markups of 50%–76% for IBs, and up to 316% for generics. Retail pharmacy markups were also high—25%–38% and 100%–140% for IBs and generics, respectively. In the public sector, where medicines are free, availability was low even for medicines on the National Essential Drugs List. For a month's treatment for peptic ulcer disease and hypertension people have to pay about a week's wages in the private sector. CONCLUSIONS: The free market by definition does not control medicine prices, necessitating price monitoring and control mechanisms. Markups for generic products are greater than for IBs. Reducing the base price without controlling markups may increase profits for retailers and dispensing doctors without reducing the price paid by end users. To increase access and affordability, promotion of generic medicines and improved availability of medicines in the public sector are required

Comparative analysis of antioxidant potential in leaf, stem, and root of Paederia foetida L.

Paederia foetida L. is widely used for the treatment of myriad ailments. Thus, searching for plant parts having greater antioxidant potential would make it easy to get suitable materials for herbal drugs. The present effort was made to explore the antioxidant potentials in the plant parts of P. foetida grown under natural conditions by means of physiological and biochemical analyses. The young leaves showed the highest reservoir of non-enzymatic antioxidants such as chlorophylls (0.96 mg g-1), carotenoids (0.43 mg g-1), anthocyanins (53.99 µg g-1), phenolics (728.24 µg g-1), flavonoids (4178.05 µg g-1), and proline (1.46 µmol g-1) as compared to others. Total antioxidant activity was found to be the highest in young leaves (84.82 %) followed by young stems (80.24 %) and matured leaves (79.78 %). Analysis of enzymatic antioxidants resulted in the superior activity of ascorbate peroxidase (13.58 µmol min-1 mg-1) and glutathione S-transferase (3409 nmol min-1 mg-1) in young leaves whereas the highest rate of catalase (409.85 µmol min-1 mg-1) and peroxidase (3.5 nmol min-1 mg-1) activity were found in matured leaves. However, comparatively higher content of reactive oxygen species; hydrogen peroxide, and lipid peroxidation product; malondialdehyde in matured leaves than that of young leaves suggests that young leaf is a suitable source for herbal medicine

Characterizing Structural Transitions Using Localized Free Energy Landscape Analysis

Structural changes in molecules are frequently observed during biological processes like replication, transcription and translation. These structural changes can usually be traced to specific distortions in the backbones of the macromolecules involved. Quantitative energetic characterization of such distortions can greatly advance the atomic-level understanding of the dynamic character of these biological processes.Molecular dynamics simulations combined with a variation of the Weighted Histogram Analysis Method for potential of mean force determination are applied to characterize localized structural changes for the test case of cytosine (underlined) base flipping in a GTCAGCGCATGG DNA duplex. Free energy landscapes for backbone torsion and sugar pucker degrees of freedom in the DNA are used to understand their behavior in response to the base flipping perturbation. By simplifying the base flipping structural change into a two-state model, a free energy difference of upto 14 kcal/mol can be attributed to the flipped state relative to the stacked Watson-Crick base paired state. This two-state classification allows precise evaluation of the effect of base flipping on local backbone degrees of freedom.The calculated free energy landscapes of individual backbone and sugar degrees of freedom expectedly show the greatest change in the vicinity of the flipping base itself, but specific delocalized effects can be discerned upto four nucleotide positions away in both 5' and 3' directions. Free energy landscape analysis thus provides a quantitative method to pinpoint the determinants of structural change on the atomic scale and also delineate the extent of propagation of the perturbation along the molecule. In addition to nucleic acids, this methodology is anticipated to be useful for studying conformational changes in all macromolecules, including carbohydrates, lipids, and proteins

Sternalis muscle: an underestimated anterior chest wall anatomical variant

Over the recent years, an increased alertness for thorough knowledge of anatomical variants with clinical significance has been recorded in order to minimize the risks of surgical complications. We report a rare case of bilateral strap-like sternalis muscle of the anterior chest wall in a female cadaver. Its presence may evoke alterations in the electrocardiogram or confuse a routine mammography. The incidental finding of a sternalis muscle in mammography, CT, and MRI studies must be documented in a patient's medical records as it can be used as a pedicle flap or flap microvascular anastomosis during reconstructive surgery of the anterior chest wall, head and neck, and breast. Moreover, its presence may be misdiagnosed as a wide range of benign and malignant anterior chest wall lesions and tumors

A theoretical model for template-free synthesis of long DNA sequence

This theoretical scheme is intended to formulate a potential method for high fidelity synthesis of Nucleic Acid molecules towards a few thousand bases using an enzyme system. Terminal Deoxyribonucleotidyl Transferase, which adds a nucleotide to the 3′OH end of a Nucleic Acid molecule, may be used in combination with a controlled method for nucleotide addition and degradation, to synthesize a predefined Nucleic Acid sequence. A pH control system is suggested to regulate the sequential activity switching of different enzymes in the synthetic scheme. Current practice of synthetic biology is cumbersome, expensive and often error prone owing to the dependence on the ligation of short oligonucleotides to fabricate functional genetic parts. The projected scheme is likely to render synthetic genomics appreciably convenient and economic by providing longer DNA molecules to start with