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Mixing in gas separation membranes has received much less attention than in membrane liquid separation because gas molecules have much smaller viscosity, allowing them to diffuse easily through membranes without requiring significant flow mixing. However, due to advancements in membrane fabrication technologies aimed at improving material properties, concentration polarization (CP) might become an issue in gas separation due to enhanced membrane efficiency and permeability. Consequently, a 2D CFD analysis is conducted to evaluate the impact of spacer-induced mixing on membrane gas concentration polarization for typical CO 2 /CH 4 gas separation. Results show that spacers generally enhance flux performance while reducing CP in the membrane channel when compared to the case without spacers. Furthermore, the effectiveness of spacer-flux-to-pressure-loss-ratio (SPFP) reaches a peak for a Reynolds number in the range of 5 < Re h < 200 because of the trade-off between flux and pressure drop. This mixing-induced flux enhancement is most effective under high CP conditions (less mixing) within the membrane channel. Similarly, flux enhancement due to spacers can be observed as membrane selectivity, pressure ratio and feed gas concentration increase due to enhanced CP. [Display omitted] • 2D CFD analysis of the impact of spacer-induced mixing on membrane gas separation. • The spacer-flux-to-pressure-loss-ratio reaches a peak at 5 < Re h < 200. • Spacer reduces CP and enhances gas permeation flux compared with empty channel. • Spacer is most effective in enhancing gas permeate flux under high CP conditions. • Spacer enhances flux as selectivity, pressure ratio and feed concentration increase. [ABSTRACT FROM AUTHOR]

Membrane-based gas separation (GS) has emerged as a competitive separation technology for industrial gas separation applications due to its simpler operation and cost-effective approach. This paper reviews the computational parameters and boundary conditions involved in model simulations, including the general assumptions made for the gas separation process. The transport mechanisms used for dense and porous gas separation membranes are discussed, followed by verification studies of CFD models. The impacts of different operation parameters, such as the temperature, pressure ratio, variation in hydrodynamics, and membrane selectivity, on membrane performance are evaluated in terms of gas permeation flux and concentration polarisation (CP). This review also describes the effect of obstacles (feed spacers) and various unsteady flow approaches for improving performance. Finally, challenges and future perspectives in CFD simulation involving membrane gas separation are provided. [Display omitted] • CFD modelling for membrane gas separation is reviewed. • Methodology of CFD modelling for dense and porous membranes is given. • Effects of different operating conditions are discussed. • Challenges and future perspectives on gas membrane CFD modelling are provided. [ABSTRACT FROM AUTHOR]

Accurate prediction of the concentration polarisation (CP) effect is very important in the design of an efficient membrane-based gas separation process. This study analyses the reliability of analytical film theory (FT) for evaluating the performance of gas separation membranes in terms of CP and flux. The analytical model is compared against a more rigorous numerical model developed by using Computational Fluid Dynamics (CFD) for various operating variables. The results show that the FT prediction is less accurate at high CP conditions when gas permeation through the membrane increases, due to higher permeance selectivity and pressure ratio. Hence, the results suggest that FT is not recommended for membranes with high permeance or high-pressure conditions. Given that the typical range of feed composition and temperature has little impact on fluid properties (i.e., gas diffusion coefficient, densities, and viscosities), the resulting CP does not vary much and hence both FT and CFD models predict a similar CP. The analysis also suggests that the FT model is more accurate in predicting CP in the region closer to the membrane entrance. Overall, the analytical film theory serves as a reliable approximation in membrane gas applications under low CP at high crossflow and low flux conditions. [Display omitted] • Comparison of CP predicted by film theory and CFD model for membrane gas separation. • Fluid properties have little impact on CP and flux predicted by FT and CFD models. • Film theory performs better in the region closer to the membrane entrance. • FT predictions are at their best for high crossflow and low flux conditions. [ABSTRACT FROM AUTHOR]

This paper describes laboratory-scale experiments for examining the impact of microwave-irradiation on the regeneration of agricultural-waste based activated carbons loaded with methylene blue (MB). The efficacy of the regeneration study was analyzed by determining the carbon yield and amount of MB adsorbed in successive adsorption-regeneration cycles. The virgin characteristics were examined by pore-structural-analysis, nitrogen adsorption-desorption curve, surface acidity/basicity and zeta-potential-measurement. Microwave heating preserved the porous structure of the regenerated activated carbons efficiently to restore the original activate sites and adsorption capacity, with the specific surface areas (SBET) of 605.88-711.74 m2/g and monolayer adsorption capacities for MB of 199.74-231.68 mg/g. Besides, the regeneration time was considerably shortened over conventional regeneration method, which represents a dramatic improvement in the adsorption chemistry. [ABSTRACT FROM AUTHOR]

A new route for the conversion of maize cobs waste, a natural low-cost lignocellulosic biomass abundantly available from the food processing industries into an eco-friendly biosorbent (CC) via chemical treatment has been presented. The effectiveness for the adsorptive removal of a highly hazardous carbamate derivative pesticide, carbofuran from the aqueous solution was attempted. The operational parameters including the effects of modification agents and chemical impregnation ratio on the adsorption capability were investigated. The porosity, functionality and surface chemistry of CC were featured by means of low temperature nitrogen adsorption, elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, evaluation of surface acidity/basicity and zeta potential measurement. The effects of adsorbent dosage, initial concentration, contact time and solution pH on the adsorption performance were evaluated in a batch mode study. Equilibrium data were simulated by non-linear fittings using the Freundlich, Langmuir, and Temkin isotherm models. Kinetic modeling was fitted to the pseudo-first-order and pseudo-second-order equations. Langmuir isotherm model provided a better correlation to the experimental data, with a maximum monolayer adsorption capacity of 149.15 mg/g, while the adsorption kinetic was best fitted to the pseudo-second-order kinetic model. The results illustrated the potential of maize cobs waste derived biosorbent for the on-site remediation of pesticide contaminated wastewater. [ABSTRACT FROM AUTHOR]

Infertility is a worldwide reproductive health problem which affects approximately 15% of couples, with male factor infertility dominating nearly 50% of the affected population. The nature of the phenomenon is underscored by a complex array of transcriptomic, proteomic and metabolic differences which interact in unknown ways. Many causes of male factor infertility are still defined as idiopathic, and most diagnosis tends to be more descriptive rather than specific. As such, the emergence of novel transcriptomic and metabolomic studies may hold the key to more accurately diagnose and treat male factor infertility. This paper provides the most recent evidence underlying the role of transcriptomic and metabolomic analysis in the management of male infertility. A summary of the current knowledge and new discovery of noninvasive, highly sensitive and specific biomarkers which allow the expansion of this area is outlined. [ABSTRACT FROM AUTHOR]

Purpose: Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (>/=50 Gy). Evidence is emerging that lower doses could also be important.Methods and Materials: Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity.Results: A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30Conclusion: Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity. [ABSTRACT FROM AUTHOR]

Abstract: Aims: The radiation dose used to treat bladder cancer is limited by the risk of inducing severe late bladder toxicity. Retrospective data suggest that radiation tolerance is greater for partial rather than whole bladder irradiation. Limiting the high-dose region to a section of the bladder may reduce toxicity, opening the way for dose escalation. The aims of this study were to establish the efficacy and compare the late toxicity between (1) a two-phase technique limiting the high-dose area and (2) a conventional single-phase radiotherapy to the whole bladder. Materials and methods: A cohort study was undertaken of 229 patients with invasive bladder cancer treated with computed tomography-planned radical radiotherapy at the Royal Marsden Hospital from 1984 to 1998. In total, 154 patients received a single-phase treatment to the whole bladder with a 2cm margin. Seventy-five patients with solitary, well-localised tumours were selected for treatment using a two-phase technique. The first phase (12Gy) aimed to treat the tumour with a 2cm margin. A second phase treated the whole bladder with 52Gy. One hundred and forty-one patients were planned to receive a dose of 60–64Gy/30–32 fractions over 6–6.5 weeks, whereas 88 patients received an accelerated regime. Data on late bladder and bowel toxicity (using Radiation Therapy Oncology Group criteria) were collected prospectively at the annual review. Results: At the 5-year follow-up there was no difference in overall survival (hazard ratio=0.91, 95% confidence interval 0.64–1.3) or failure-free survival (hazard ratio=1.02, 95% confidence interval 0.73–1.43) between the two techniques. The two-phase reduced volume treatment was less toxic, with a 19% absolute reduction in overall grade 3–4 late toxicity (P =0.02). These differences were more marked for bladder toxicity compared with bowel toxicity. Conclusions: The two-phase reduced volume technique was associated with less bladder and bowel toxicity than conventional whole bladder radiotherapy without evidence of impaired survival. [Copyright &y& Elsevier]

In this prospective cohort study we analyzed the impact of admission renal function on the hospital course of 2,503 patients with unstable angina pectoris (UAP) and acute myocardial infarction (AMI). The patients were stratified into quartile groups (Q1 to Q4) defined by baseline corrected creatinine clearance (cCrCl) values of 51.4, 63.8, and 76.8 mg/min/72 kg. The proportions of patients with a discharge diagnosis of AMI increased with declining cCrCl, from 35.5% in Q4 to 46.0% in Q1 (p <0.0001). The frequency of left ventricular (LV) failure (Q4 4.5%, Q1 31.0%, p <0.0001) and cardiac death (Q4 0.5%, Q1 9.5%, p <0.0001) also increased linearly with decreasing cCrCl, with no evidence that the prognostic impact of renal dysfunction was different in AMI or UAP (p for interaction 0.15). Logistic regression analysis confirmed the independent effects of cCrCl on outcome, with odds of LV failure and cardiac death for patients in Q4 being 0.34 (95% confidence intervals 0.16 to 0.72) and 0.14 (95% confidence intervals 0.03 to 0.74), respectively, relative to patients in Q1. No threshold was detected for the adverse effects of renal dysfunction on outcomes; the log odds of LV failure and cardiac death against quartiles of cCrCl both showed significant linear trends (p <0.0001) with each change in quartile, resulting in risk reductions of 55% (odds [SE] 0.45 [0.03]) and 65% (odds [SE]: 0.35 [0.05]), respectively. In conclusion, renal function showed a graded association with LV failure and hospital death that was independent of diagnosis (UAP or AMI) and other baseline variables. There was no detectable threshold of renal dysfunction for these adverse prognostic effects. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the interactions between forced transient flow and eddy inducers (i.e. spacers) in spiral wound membrane modules results in significant mass transfer enhancement and reduction in concentration polarisation (CP). This paper uses CFD to investigate the effect of varying the spacer geometric parameters on the resonant frequency for an unsteady forced-slip, as well as the resulting permeate flux enhancement, for a 2D zig-zag spacer. The analysis shows that the resonant frequency is significantly affected by the interaction of the shear layer with successive downstream spacers. The effectiveness of forced-slip reaches a peak (up to 15.6% flux increase) for a spacer size in the range of 0.5< d f / h ch <0.6 because of the trade-off between mixing-induced forced-slip and the CP modulus. In addition, vortex shedding is suppressed for smaller spacer sizes (d f / h ch ≤0.4), because viscous forces dominate over convective forces due to a smaller filament Reynolds number. As the distance between filaments is increased, the increase in flux due to forced-slip is greater (up to 31.5%), albeit the actual flux decreases because the boundary layer is more developed. These results also reinforce the finding that forced-slip is more efficient for spacer designs with poor mixing (i.e. high CP). • CFD analysis of SWMs combining unsteady flow perturbations and eddy inducers. • Feed spacer geometry significantly affects perturbation resonant frequency. • Relative flux enhancement peaks at spacer sizes of 0.5< d f / h ch <0.6 • Vortex shedding is suppressed for smaller spacer sizes (d f / h ch ≤0.4). • Flow perturbation techniques are more effective for spacers with poor mixing. [ABSTRACT FROM AUTHOR]

Quality assurance in radiotherapy (QART) is essential to ensure the scientific integrity of a clinical trial. This paper reports the findings of the retrospective QART assessment for all centres that participated in PORTEC-3; a randomised controlled trial that compared pelvic radiotherapy with concurrent chemoradiotherapy to the pelvis followed by adjuvant chemotherapy. The trial showed an overall survival benefit for the addition of the chemotherapy in the management of women with high-risk endometrial cancer. Clinicians were invited to upload a randomly selected case/s treated at each of the participating sites. Panel reviewers analysed the contours to certify that the target volumes and organ at risk structures were contoured according to guidelines. The results were categorised into acceptable, minor variation, major variation or unevaluable. The radiotherapy plans were dosimetrically evaluated using the well-established Trans-Tasman Radiation Oncology Group (TROG) protocol. Between August 2010 and January 2018, data from 146 patients of 686 consecutively treated patients were retrospectively reviewed. All 16 Australia and New Zealand and 71 of 77 international centres uploaded data for evaluation. In total, 3514 dosimetric and contour variables were reviewed. Of these, 3136 variables were deemed acceptable (89.2%), with 335 minor (9.6%) and 43 major variations (1.2%). Major contour variations included the clinical target volume vaginal vault, clinical target volume parametria and differential planning target volume vault expansion. The results of the QART assessment confirmed high uniformity and low rates of both minor and major deviations in contouring and dosimetry in all sites. This supports the safe introduction of the PORTEC-3 treatment protocol into routine clinical practice. • Radiotherapy benchmarking reduces the major and minor deviations noted in contouring and dosimetry. • Incorporation of a quality QART programme reduces source bias and facilitates adoption of the trial results. • Inclusion of real-time QART will improve and standardise international radiotherapy quality in future trials. [ABSTRACT FROM AUTHOR]

Background: Existing evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients. Patients and methods: Chemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colonystimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (HeadminderTM) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain. Results: Ninety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P=0.023), and a higher concentration of IL-4 was associated with better response speed performance (P=0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P=0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P=0.022). Conclusions: While elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapyassociated cognitive changes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Resectable oesophageal cancer is often treated with surgery alone or with preoperative (neoadjuvant) chemoradiotherapy or chemotherapy. We aimed to clarify the benefits of neoadjuvant chemoradiotherapy or chemotherapy versus surgery alone by a meta-analysis of randomised trial data. METHODS: Eligible trials were identified first from earlier published meta-analyses and systematic reviews. We also used MEDLINE, Cancerlit, and EMBASE databases to identify additional studies and published abstracts from major scientific meetings since 1980. Only randomised studies with an analysis by an intention-to-treat principle were included, and searches were restricted to those databases citing articles in English. We used published hazard ratios if available or estimates from other survival data or survival curves. Treatment effects by type of tumour and treatment sequencing were also investigated. FINDINGS: Ten randomised comparisons of neoadjuvant chemoradiotherapy versus surgery alone (n=1209) and eight of neoadjuvant chemotherapy versus surgery alone (n=1724) in patients with local operable oesophageal carcinoma were identified. The hazard ratio for all-cause mortality with neoadjuvant chemoradiotherapy versus surgery alone was 0.81 (95% CI 0.70-0.93; p=0.002), corresponding to a 13% absolute difference in survival at 2 years, with similar results for different histological tumour types: 0.84 (0.71-0.99; p=0.04) for squamous-cell carcinoma (SCC), and 0.75 (0.59-0.95; p=0.02) for adenocarcinoma. The hazard ratio for neoadjuvant chemotherapy was 0.90 (0.81-1.00; p=0.05), which indicates a 2-year absolute survival benefit of 7%. There was no significant effect on all-cause mortality of chemotherapy for patients with SCC (hazard ratio 0.88 [0.75-1.03]; p=0.12), although there was a significant benefit for those with adenocarcinoma (0.78 [0.64-0.95]; p=0.014). INTERPRETATION: A significant survival benefit was evident for preoperative chemoradiotherapy and, to a lesser extent, for chemotherapy in patients with adenocarcinoma of the oesophagus. The findings provide an evidence-based framework for the use of neoadjuvant treatment in management decisions. [ABSTRACT FROM AUTHOR]