UV-VIS spectral evaluation of CR-39 detector exposed with diagnostic dosage

The effects of the X-ray irradiation and chemical etching on the physical and optical properties of CR-39 plastic detectors were investigated for different doses of X-ray. CR-39 detectors were etched in the solution of the 3 M of NaOH after irradiation for revelations of the track. The tracks formed on CR-39 either by irradiated X-ray or due to the effect of environment. The changes in the thickness after exposed have significant decrease in 60 kVp and started to increase in the range of 70 kVp up to 100 kVp due to the formation of oxidation layer on surface by free radicals. The optical band gaps before etching and after etching were determined by using Ultraviolet-visible (UV-Vis) spectroscopy. The optical band gap is attributed to the indirect transition due to its amorphous nature which is significantly decline trend energy in increase of the energy fluence of radiation. The Urbach’s energy, is defined as the width of the tail localized states in the forbidden band gap which change increment trend as increase in dose delivered due to the distortion structure of the CR-39 in terms of the electron charges in valences electron hence attributes to the induced modification of angle bond between the neighboring atoms

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Optical properties of lithium borate glass (Li2O)x (B2O3)1-x

A series of (Li2O)x(B2O3)1-x has been synthesized with mole fraction x=0.10, 0.15,0.20,0.25 and 0.30 mol% using melt quenching method. The structure of the glass system was determined by FTIR and X-ray diffraction. The density and molar volume were determined and the density increases with Li2O content whereas molar volume decreases with Li2O. Refractive index of glass samples were measured by ellipsometer. Refractive index increases with increase of Li2O. The absorption spectra of the studied glass showed that position of fundamental absorption edge shifts to longer wavelength with Li2O. Optical band gap varies from 0.10 to 2.22 eV and Urbach energy varies from 2.91 to 1.55 eV. The variation in optical band gap and Urbach energy were due to the variation in the glass structure

Hypersensitivity and nephelauxetic effect of Er3+ in bismuth tellurite glass system

The optical absorption and emission properties of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glass system had been analyzed to investigate the hypersensitivity shift and its mechanism. According to the Covalent model, the hypersensitive shift indicated by the drop of F2 at x = 5 mol% can be attributed to charge transfer from O2– ligands to Er3+ ions meanwhile according to the Dielectric screening model, drop of F2 may due to Er3+ ions contraction. The dynamic coupling mechanism was used to explain hypersensitivity transition probabilities in non-centrosymmetric systems. The addition of Bi2O3 may modify the site symmetry of Er3+ ions and oxygen to a high asymmetry τ2, resulting in an asymmetrical electron distribution, thus increasing Er-O covalency, as shown by the maximum Ω2 value at x = 5 mol%. The Er3+ ions site symmetry was investigated using Hamiltonian crystal field fitting in the frame of the D4 point symmetry model, which yielded maximum crystal field strength Nv at x = 5 mol%, indicating low point symmetry distortion of the Er3+ ions site symmetry

Polymethacrylic Gel (Pmag) as a Point Dosimeter.

Polymethacrylic gel (PMAG) of different concentrations of MAA and BIS were irradiated using γ-rays produced by 60Co radionuclide with the absorbed doses ranging from 0 Gy to 19 Gy. Due to the radiation-induced polymerization processes, the formation of Polymethacrylic gel (PMAG) occurs, which causes the dose response mechanism increased in the Nuclear Magnetic Resonance (NMR) relaxation rates of protons. The relaxation rate R2 (1/T2) are fitted to the functional form y as a function of absorbed dose D was found to have a monoexponential expression in the form; y= y + A (1-e -D/D). The relaxation rate (ΔR2) dose sensitivity value (12.5 + 0.1 Gy) of MAA monomer by Lepage, et al 2001 is comparable with PMAAG experimental value gained which are 12.6 + 0.1 Gy. The dose sensitivity, D0 and half dose, D1/2 was found increasing with the concentrations of MAA monomer and BIS crosslinker. The slope parameter kBIS > kMAA indicates that consumption of crosslinker is much faster than monomer. Eventually, UV-Vis spectrophotometer was used to record PMAG degree of absorption. The PMAG has a mean value of absorption of 0.614 at 375 nm. The dose derived from PMAG is comparable to Fricke dosimeter and ionization chamber readings between 4.7 ± 0.1% and 11.6 ± 0.1%. The dose errors of less than 10 ± 0.1% are considered acceptable in radiation processing, an improvement of accuracy less than 5.0 ± 0.1% is acceptable in radiotherapy. This effort is to undertake the study of precision and accuracy associated with the use of Fricke and polymer gel in optimizing the usage of gels for dosimetry

Major health impact of accelerated aging in young HIV-infected individuals on antiretroviral therapy

Background: Aging among HIV-infected individuals on antiretroviral therapy (ART) is a significant clinical challenge; however, studies assessing multidimensional aspects of aging are lacking. We characterized 10 geriatric conditions encompassing multiple functional domains, its health impact and associated risk factors in HIV-infected and age-matched uninfected controls. Methods: HIV-infected individuals were recruited from the outpatient clinic in University Malaya Medical Centre, Malaysia and controls from the community. All participants were aged at least 25 years of age with no acute illness, and HIV-infected individuals were on stable ART. Geriatric conditions were assessed and the burden scored as a composite of geriatric conditions present in an individual (total score = 10). Multivariate regression analysis was performed to determine the risk factors and health impact associated with the burden of geriatric conditions. Results: We analyzed data from 336 HIV-infected individuals (total HIV+), of whom 172 were matched for age, sex, and ethnicity with 172 HIV-uninfected controls (matched subset). In the total HIV-positive cohort, median (interquartile range) age was 44 (38-51) years and CD4 T-cell count was 562 (398-737) cells/μl. The burden of geriatric conditions was significantly higher in the HIV-infected group compared with controls (P < 0.001). With an increasing geriatric condition burden, quality-of-life scores were 2.2-times poorer, healthcare use five times greater, and mortality risk scores four times higher in the HIV-infected group compared with matched controls. Both sociobehavioural and HIV-related clinical factors were independently associated with an increasing burden of geriatric condition in HIV. Conclusions:A high burden of geriatric conditions with significant impact on health outcomes, including mortality risk scores are observed among HIV-infected individuals on ART in a resource-limited setting

The Global Alliance for Infections in Surgery: defining a model for antimicrobial stewardship-results from an international cross-sectional survey

Contains fulltext : 177987.pdf (publisher's version ) (Open Access)BACKGROUND: Antimicrobial Stewardship Programs (ASPs) have been promoted to optimize antimicrobial usage and patient outcomes, and to reduce the emergence of antimicrobial-resistant organisms. However, the best strategies for an ASP are not definitively established and are likely to vary based on local culture, policy, and routine clinical practice, and probably limited resources in middle-income countries. The aim of this study is to evaluate structures and resources of antimicrobial stewardship teams (ASTs) in surgical departments from different regions of the world. METHODS: A cross-sectional web-based survey was conducted in 2016 on 173 physicians who participated in the AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections) project and on 658 international experts in the fields of ASPs, infection control, and infections in surgery. RESULTS: The response rate was 19.4%. One hundred fifty-six (98.7%) participants stated their hospital had a multidisciplinary AST. The median number of physicians working inside the team was five [interquartile range 4-6]. An infectious disease specialist, a microbiologist and an infection control specialist were, respectively, present in 80.1, 76.3, and 67.9% of the ASTs. A surgeon was a component in 59.0% of cases and was significantly more likely to be present in university hospitals (89.5%, p < 0.05) compared to community teaching (83.3%) and community hospitals (66.7%). Protocols for pre-operative prophylaxis and for antimicrobial treatment of surgical infections were respectively implemented in 96.2 and 82.3% of the hospitals. The majority of the surgical departments implemented both persuasive and restrictive interventions (72.8%). The most common types of interventions in surgical departments were dissemination of educational materials (62.5%), expert approval (61.0%), audit and feedback (55.1%), educational outreach (53.7%), and compulsory order forms (51.5%). CONCLUSION: The survey showed a heterogeneous organization of ASPs worldwide, demonstrating the necessity of a multidisciplinary and collaborative approach in the battle against antimicrobial resistance in surgical infections, and the importance of educational efforts towards this goal