Evaluation of a nanoporous lyotropic liquid crystal polymer membrane for the treatment of hydraulic fracturing produced water via cross-flow filtration

Current commercial nanofiltration and reverse osmosis membranes are limited in scope and performance due to their physicochemical properties. Desalination of hydraulic fracturing wastewater poses a particular challenge to membrane filtration given the high concentrations of both organic compounds and salts present in these waters. The recently-developed nanoporous, bicontinuous cubic, lyotropic liquid crystal, thin-film-composite polymer membrane (TFC Q membrane), having unique physicochemical properties, enables an alternative treatment of hydraulic fracturing wastewater. Specifically, the TFC Q membrane recovers the organic compounds from this high-salinity wastewater, enabling biodegradation to occur after desalination. However, other performance criteria must be demonstrated for a membrane to reach application. The work presented herein demonstrates the stable performance of the TFC Q membrane during 66 h of cross-flow filtration of hydraulic fracturing produced water. Compared to the commercial NF90 membrane, the TFC Q membrane recovered a larger portion of the organic compounds, had a higher thickness-normalized water flux, and fouled less. The combination of the TFC Q membrane's selectivity with its reduced fouling propensity makes possible a treatment for hydraulic fracturing wastewater and other complex aqueous streams inaccessible by most commercial membranes, motivating the further study and development of the TFC Q membrane. I I I I I

Chemical genetic analysis of the regulatory role of Cdc2p in the S. pombe septation initiation network

The protein kinase Cdc2p is the master regulator of cell cycle progression in the fission yeast Schizosaccharomyces pombe. It is required both for entry into mitosis and for onset of DNA replication. Cdc2p must be inactivated to permit exit from mitosis, licensing of replication origins and cytokinesis. To study the role of Cdc2p in greater detail, we generated a cdc2 allele that is sensitive to an inhibitory ATP analogue. We show that the inhibitor-induced cell cycle arrest is reversible and examine the effect of inhibiting Cdc2p on the regulation of the septation initiation network (SIN), which controls the initiation of cytokinesis in S. pombe. We found that specific inactivation of Cdc2p in a mitotically arrested cell promotes the asymmetrical recruitment of SIN proteins to the spindle poles and the recruitment of the most downstream SIN components and beta-(1,3) glucan synthase to the contractile ring. Thus, we conclude that inactivation of Cdc2p is sufficient to activate the SIN and promote cytokinesis

A reduced-order model of concentration polarization in reverse osmosis systems with feed spacers

Feed spacers in reverse osmosis systems generate complex fluid flows that limit computational fluid dynamics (CFD) simulations to small length and time scales. That limits our ability to simulate mineral scaling and other membrane fouling phenomena, which occur over longer length and time scales. Thus motivated, we develop a reduced model that replaces the CFD simulation of the velocity field with an analytical model that mimics spacers. This focuses the remaining numerical effort on simulating the advection–diffusion equation governing solute transport. We motivate and validate the model with CFD simulations and bench-scale experiments of spacer filaments in three different arrangements, including cases of unsteady vortex shedding. We show that the model produces a roughly 10,000-fold speedup compared to CFD, and accurately reproduces CFD predictions of not only the average and maximum concentrations, but also the local concentration distribution along the membrane. We also demonstrate the model for simulating a feed channel with a length-to-height ratio of 200. The model provides a simple testbed for exploratory studies of multispecies transport, precipitation, and membrane fouling phenomena for which simulating spacers is often prohibitive

Measuring track vertical stiffness through dynamic monitoring

[EN] This paper proposes a methodology for the evaluation of the track condition by means of the measurement of the track stiffness. This magnitude is calculated from vertical acceleration data measured at the axle box of trains during their normal operation. From the corresponding vertical acceleration spectra, the dominant vibration frequencies for each track stretch are identified and the combined stiffness is then determined. Then the stiffness without the contribution of the rail is calculated. The results obtained for a High Speed ballasted track in several track stretches are within the range 120-130 kN/mm, a result consistent with direct stiffness measurements taken during previous studies. Therefore, the proposed methodology may be used to obtain a first insight to the track condition by means of a continuous measurement of the track combined stiffness. This offers an alternative to traditional stationary stiffness measuring devices and might be a useful complement to dedicated continuous monitoring vehicles.Cano, MJ.; Martínez Fernández, P.; Insa Franco, R. (2016). Measuring track vertical stiffness through dynamic monitoring. Proceedings of the Institution of Civil Engineers - Transport. 169(1). doi:10.1680/jtran.14.00081S169

Analysis of the performance of under-sleeper pads in highspeed line transition zones

[EN] In many high-speed railway lines, the zones between embankments and structures may present some discontinuities, in terms of track geometry and track stiffness, which may create discomfort for passengers, induce deterioration of track and vehicle materials and even raise the risk of derailment to dangerous levels. In the attempt to attenuate the consequences of such problems, some solutions pointing at progressively changing the vertical stiffness in the railway track have been tested, such as transition zones or pads placed either between the rails and the sleepers or under the sleepers. The contribution of under-sleeper pads in transition regions and their effect on the railway infrastructure is specifically analysed in the present paper. The results obtained are of interest since they provide useful information for railway managers on infrastructure design and justify the need to implement such transition ones.Insa Franco, R.; Salvador Zuriaga, P.; Inarejos Mesa, J.; Medina González, L. (2014). Analysis of the performance of under-sleeper pads in highspeed line transition zones. Proceedings of the Institution of Civil Engineers - Transport. 167(2):63-77. doi:10.1680/tran.11.00033S6377167

Responses to systemic therapy in metastatic pheochromocytoma/paraganglioma: a retrospective multicenter cohort study

OBJECTIVE The therapeutic options for metastatic pheochromocytomas/paragangliomas (mPPGLs) include chemotherapy with cyclophosphamide/vincristine/dacarbazine (CVD), temozolomide monotherapy, radionuclide therapies, and tyrosine kinase inhibitors such as sunitinib. The objective of this multicenter retrospective study was to evaluate and compare the responses of mPPGLs including those with pathogenic variants in succinate dehydrogenase subunit B (SDHB), to different systemic treatments. DESIGN This is a retrospective analysis of treatment responses of mPPGL patients (n = 74) to systemic therapies. METHODS Patients with mPPGLs treated at 6 specialized national centers were selected based on participation in the ENSAT registry. Survival until detected progression (SDP) and disease-control rates (DCRs) at 3 months were evaluated based on imaging reports. RESULTS For the group of patients with progressive disease at baseline (83.8% of 74 patients), the DCR with first-line CVD chemotherapy was 75.0% (n = 4, SDP 11 months; SDHB [n = 1]: DCR 100%, SDP 30 months), with somatostatin peptide receptor-based radionuclide therapy (PPRT) 85.7% (n = 21, SDP 17 months; SDHB [n = 10]: DCR 100%, SDP 14 months), with 131I-meta-iodobenzylguanidine (131I-MIBG) 82.6% (n = 23, SDP 43 months; SDHB [n = 4]: DCR 100%, SDP 24 months), with sunitinib 100% (n = 7, SDP 18 months; SDHB [n = 3]: DCR 100%, SDP 18 months), and with somatostatin analogs 100% (n = 4, SDP not reached). The DCR with temozolomide as second-line therapy was 60.0% (n = 5, SDP 10 months; SDHB [n = 4]: DCR 75%, SDP 10 months). CONCLUSIONS We demonstrate in a real-life clinical setting that all current therapies show reasonable efficacy in preventing disease progression, and this is equally true for patients with germline SDHB mutations

Adolescents' health and health behaviour as predictors of injury death. A prospective cohort follow-up of 652,530 person-years

<p>Abstract</p> <p>Background</p> <p>Injuries represent an important cause of mortality among young adults. Longitudinal studies on risk factors are scarce. We studied associations between adolescents' perceived health and health behaviour and injury death.</p> <p>Methods</p> <p>A prospective cohort of 57,407 Finns aged 14 to 18 years was followed for an average of 11.4 years. The end-point of study was injury death or termination of follow-up in 2001. The relationships of eight health and health behaviour characteristics with injury death were studied with adjusted Cox's proportional hazard model.</p> <p>Results</p> <p>We identified 298 (0.5%) injury deaths, 232 (0.9%) in men and 66 (0.2%) in women. The mean age at death was 23.8 years. In the models adjusted for age, sex and socioeconomic background, the strongest risk factors for injury death were recurring drunkenness (HR 2.1; 95% CI: 1.4–3.1) and daily smoking (HR 1.7; 95% CI: 1.3–2.2). Poor health did not predict injury death. Unintentional and intentional injury deaths had similar health and health behavioural risk factors.</p> <p>Conclusion</p> <p>Health compromising behaviour adopted at adolescence has a clear impact on the risk of injury death in adulthood independent from socioeconomic background. On the other hand, poor health as such is not a significant predictor of injury death. Promotion of healthy lifestyle among adolescents as part of public health programmes would seem an appropriate way to contribute to adolescent injury prevention.</p