Steady-State Radiolysis of Supercritical Water: Model Predictions and Validation

Chemical kinetic models are being developed for the γ-radiolysis of subcritical and supercritical water (SCW) to estimate the concentrations of radiolytically produced oxidants. Many of the physical properties of water change sharply at the critical point. These properties control the chemical stability and transport behavior of the ions and radicals generated by the radiolysis of SCW. The effects of changes in the solvent properties of water on primary radiolytic processes and the subsequent aqueous reaction kinetics can be quite complicated and are not yet well understood. The approach used in this paper was to adapt an existing liquid water radiolysis model (LRM) that has already been validated for lower temperatures and a water vapor radiolysis model (VRM) validated for higher temperatures, but for lower pressures, to calculate radiolysis product speciation under conditions approaching the supercritical state. The results were then extrapolated to the supercritical regime by doing critical analysis of the input parameters. This exercise found that the vapor-like and liquid-like models make similar predictions under some conditions. This paper presents and discusses the LRM and VRM predictions for the concentrations of molecular radiolysis products, H2, O2, and H2O2 at two different irradiation times, 1 s and 1 hr, as a function of temperature ranging from 25°C to 400°C. The model simulation results are then compared with the concentrations of H2, O2, and H2O2 measured as a function of γ-irradiation time at 250°C. Model predictions on the effect of H2 addition on the radiolysis product concentrations at 400°C are presented and compared with the experimental results from the Beloyarsk Nuclear Power Plant (NPP).

Structure–properties relationship in diketopyrrolopyrrole based small molecules using functional terminal side chains via direct arylation: a joint experimental and theoretical study

The role of terminal side chains in diketopyrrolopyrrole based small molecules has been analyzed, demonstrating how their optoelectronic properties vary.

Dioxin sensing properties of graphene and hexagonal boron nitride based van der Waals solids: a first-principles study

The changes in the electronic properties of single and bilayers of graphene and hexagonal boron nitride two dimensional sheets have been investigated upon interaction with 2,3,7,8-tetrachlorodibenzo-p-dioxin by employing the DFT calculations.

Design of medium band gap random terpolymers containing fluorene linked diketopyrrolopyrrole and thiophene co-monomers: an experimental and theoretical study

Six different random terpolymers were synthesised and their optoelectronic properties were fine-tuned by varying the thiophene strength.

Quantum chemical design of carbazole- and pyridoindole-based ambipolar host materials for blue phosphorescent OLEDs

Structure–property relationship of carbazole- and pyridoindole-type host materials for blue PhOLEDs using quantum chemical calculations.

Impact of early thiopurines on surgery in 2770 children and young people diagnosed with inflammatory bowel disease: a national population-based study

BACKGROUND

The role of early thiopurine treatment in inflammatory bowel disease (IBD) is unproven.

AIM

To quantify the impact of timing and duration of thiopurines on the risk of first surgery in children and young people with IBD using a population-based cohort.

METHODS

We constructed an incident cohort of children and young people aged <25 years, diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) from 1990 to 2009. We used Cox proportional hazards modelling to determine the impact of early thiopurine use, commenced within a year of diagnosis on risk of first surgery.

RESULTS

We identified 1595 and 1175 incident cases of CD and UC respectively with a mean length of follow-up of 4.3 years/person. There were 216 (13.5%) and 73 (6.2%) surgeries for CD and UC patients between 1990 and 2009 respectively. In CD among thiopurine users, the absolute risk of surgery at 5 years for early thiopurine use vs. late was 15.3% (95% CI: 10.5-22.1) vs. 22.1% (95% CI: 18.1-26.9) respectively. After adjustment, the early use of thiopurines was associated with a reduction in risk of first surgery of 39% (HR 0.61, 95% CI: 0.41-0.91) over the 20-year study period. In UC, early thiopurine use offered no additional benefit.

CONCLUSIONS

In Crohn's disease, early treatment with thiopurines in children and young people is associated with an appreciable reduction in the risk of surgery, but early treatment does not reduce surgical risk in UC.

Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

Interaction of collagen like peptides with gold nanosurfaces: a molecular dynamics investigation

In this study, an attempt has been made to understand the interaction between collagen like peptides (CPs) with a gold nanosurface (AuNS) using a classical molecular dynamics simulation.

The impact of timing and duration of thiopurine treatment on colectomy in ulcerative colitis: a national population-based study of incident cases between 1989-2009

BACKGROUND

The role of thiopurines in altering the risk of colectomy in ulcerative colitis (UC) remains unclear.

AIMS

To examine predictors of colectomy in UC and determine the impact of thiopurines on the risk of colectomy.

METHODS

We constructed a population-based cohort of incident cases of UC in the United Kingdom between 1989 and 2009. We determined trends in thiopurine usage and colectomy for three defined cohorts: era 1 (1989-1995), era 2 (1996-2002), era 3 (2003-2009). We used Cox regression to determine predictors of colectomy and quantified the impact of duration and timing of thiopurine use on the risk of colectomy.

RESULTS

We identified 8673 incident cases of UC. 5-year colectomy rates increased from 4.2%, 5.1% to 6.9% (P = 0.001) for era 1, era 2 and era 3, respectively, despite increasing thiopurine use. This was not significant after adjustment for predictors of colectomy (P = 0.06). There was a higher risk of colectomy in men (HR 1.44, 95% CI: 1.19-1.73), those diagnosed at an early age (HR 1.35, 95% CI: 1.04-1.75; 16-24 vs. 25-64) and early steroid users (HR 1.94, 95% CI: 1.59-2.37). 5-ASA users were less likely to require a colectomy (HR 0.35, 95% CI: 0.28-0.44). Amongst thiopurine users, those treated for greater than 12 months had a 71% reduction in risk of colectomy (HR 0.29, 95% CI: 0.21-0.40). Early thiopurines offered no additional benefit.

CONCLUSIONS

Thiopurine exposure for greater than 12 months reduces the likelihood of colectomy by 71%. Young men and those requiring steroids within 3 months of diagnosis are at greatest risk of colectomy, and most likely to benefit from sustained thiopurine use.

Immune response to tissue-restricted self-antigens induces airway inflammation and fibrosis following murine lung transplantation

Immune responses against lung-associated self-antigens (self-Ags) are hypothesized to play a role in the development of chronic lung graft rejection. We determined whether immune responses to lung self-Ags, K-alpha-1-tubulin (Kα1T) and Collagen V (Col-V) in the absence of alloimmunity, could promote airway inflammation and fibrosis. Following syngeneic murine orthotopic lung transplantation (LTx) we administered antibodies (Abs) to either Kα1T or Col-V or in combination to both of these self-Ags. As compared to recipients of isotype control Abs, Kα1T Abs and/or Col-V Abs-treated recipients had marked lung graft cellular infiltration and bronchiolar fibrosis. This inflammation was also associated the accumulation of Kα1T and Col-V-specific interferon-γ+ and IL-17+ T cells. Notably, the administration of Abs to Kα1T led to cellular and humoral immune responses to Col-V prior to development of fibrosis, and vice versa, indicating that epitope spreading can occur rapidly in an alloantigen independent manner. Collectively, these data support a model of chronic LTx rejection where the progressive loss of self-tolerance through epitope spreading promotes airway fibrosis. Strategies that target autoreactive Abs may be useful to inhibit chronic rejection of lung grafts.

High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus

High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time.

Clindamycin 1% Nano-emulsion Gel Formulation for the Treatment of Acne Vulgaris: Results of a Randomized, Active Controlled, Multicentre, Phase IV Clinical Trial

BACKGROUND

Acne vulgaris of the face is a common dermatological disease with a significant impact on the quality of life, psychosocial development as well as self-esteem of the patients. Nano emulsion gel formulations are said to have various advantages over the conventional formulations.

AIM

The present study was conducted to assess the comparative efficacy and safety of a nano-emulsion gel formulation of clindamycin with its conventional formulation in the treatment of acne vulgaris of the face.

MATERIALS AND METHODS

This prospective, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by a nano emulsion gel formulation or conventional gel formulation of clindamycin (as phosphate) 1% locally applied twice daily for 12 weeks as per random allocation. Acne lesion counts (inflammatory, non-inflammatory and total) and severity grading were carried out on the monthly scheduled visits along with tolerability assessments.

RESULTS

A total of 200 patients (97 males) were included for Intention to Treat analysis in the trial with 100 patients in each group. Reductions in total (69.3 vs. 51.9%; p<0.001), inflammatory (73.4 vs. 60.6%; p<0.005) and non inflammatory (65.1 vs. 43.7%; p<0.001) acne lesions were reported to be significantly greater with the nano-emulsion gel formulation as compared to the conventional gel formulation. Significantly more reduction in the mean acne severity score was noticeable with the nano-emulsion gel formulation (-1.6 ± 0.9 vs. -1.0 ± 0.8; p<0.001) than the comparator. A trend towards better safety profile of the nano emulsion gel formulation was reported.

CONCLUSION

In the treatment of acne vulgaris of the face, clindamycin nano emulsion gel formulation appears to be more effective than the conventional gel formulation and is also well tolerated.

Discovery of potent inhibitor for matrix metalloproteinase-9 by pharmacophore based modeling and dynamics simulation studies

Matrix metalloproteinase-9 (MMP-9) is an attractive target for anticancer therapy. In the present study ligand based pharmacophore modeling was performed to elucidate the structural elements for a diverse class of MMP-9 inhibitors. The pharmacophore model was validated through Güner-Henry (GH) scoring method. The final pharmacophore model consisted of three hydrogen bond acceptors (HBA), and two ring aromatic regions (RA). This model was utilized to screen the natural compound database to seek novel compounds as MMP-9 inhibitors. The identified hits were validated using molecular docking and molecular dynamics simulation studies. Finally, one compound named Hinokiflavone from Juniperus communis had high binding free energy of -26.54kJ/mol compared with the known inhibitors of MMP-9. Cytotoxicity for hinokiflavone was evaluated by MTT assay. Inhibition of MMP-9 in the presence of hinokiflavone was detected by gelatin zymography and gelatinolytic inhibition assay. Results revealed that the natural compounds derived based on the developed pharmacophore model would be useful for further design and development of MMP-9 inhibitors.

Obstetric outcome of ethnic Turkish women in London: a retrospective case-control study

There is concern that the maternal mortality in ethnic minority women is significantly greater than that of Caucasian British women. The objective of this study was to compare the demographic and obstetric outcomes between these two groups. Data were collected retrospectively over a 2-year period from 148 index and 148 control cases. The study group had statistically similar maternal age, labour duration, blood loss and mode of delivery compared with Caucasian British women (p > 0.05). A total of 68% of Turkish women spoke little or no English; were more likely to be non-smokers and also more likely to be married to unemployed spouses (p = 0.0001). This is the first study comparing obstetric outcomes of immigrant Turkish women with their Caucasian British counterparts. There was no significant difference in maternal or fetal outcomes, which could be attributed to the 'healthy migrant' theory, coupled with increased vigilance in ethnic minority pregnancies.