Construction of a pulsed perforated-plate extraction unit

Liquid-liquid extraction is an important operation in the production and reprocessing of nuclear fuels. In the purification of uranium by liquid-liquid extraction, uranyl nitrate is separated from impurities by extraction into an organic solvent, followed by re-extraction into an aqueous phase. Further processing of the aqueous uranyl nitrate solution is tailored to yield uranium metal or any desired uranium compound. In order that students in nuclear and chemical engineering may have an understanding of the practical as well as theoretical aspects of liquid-liquid extraction, a model of a uranium purification plant was designed and built in the Unit Operations Laboratory of the Missouri School of Mines and Metallurgy. For reasons of safety, the system used in the model could not include radioactive materials or heavy metals; therefore, the chemical processing of nuclear fuels was illustrated using methanol, trichloroethylene, and water. The model includes a rotating disc extraction column and a pulsed perforated-plate column for carrying out separations based on solubility relationships, and a bubble cap distillation column in which separations are based on vapor pressure differences. Methanol (representing uranyl nitrate) was extracted from a methanol-trichloroethylene solution (representing the impure uranyl nitrate solution) into a water phase (which represented the organic solvent). The resulting methanol-water solution was separated in a distillation column which represented the re-extraction of uranyl nitrate into an aqueous phase. The model unit was highly instrumented to illustrate the use and operation of control instruments and to provide a permanent record of important variables. Analytical instruments were included to provide additional information necessary to the study of material and energy relationships. The extraction and distillation columns were glass to allow visual observation of their operation. The objectives of this investigation were: to construct a pulsed perforated-plate extraction column and associated equipment which, together with the rotating disc column, comprise the extraction unit; to prepare operating instructions; and to perform preliminary experiments in the equipment --Introduction, pages 1-2

Clustering of patients with overactive bladder syndrome

BACKGROUND: Overactive bladder is a heterogenous condition with poorly characterized clinical phenotypes. To discover potential patient subtypes in patients with overactive bladder (OAB), we used consensus clustering of their urinary symptoms and other non-urologic factors. METHODS: Clinical variables included in the k-means consensus clustering included OAB symptoms, urinary incontinence, anxiety, depression, psychological stress, somatic symptom burden, reported childhood traumatic exposure, and bladder pain. RESULTS: 48 OAB patients seeking care of their symptoms were included. k-means consensus clustering identified two clusters of OAB patients: a urinary cluster and a systemic cluster. The systemic cluster, which consisted of about half of the cohort (48%), was characterized by significantly higher psychosocial burden of anxiety (HADS-A, 9.5 vs. 3.7, p \u3c 0.001), depression (HADS-D, 6.9 vs. 3.6, p \u3c 0.001), psychological stress (PSS, 21.4 vs. 12.9, p \u3c 0.001), somatic symptom burden (PSPS-Q, 28.0 vs. 7.5, p \u3c 0.001), and reported exposure to traumatic stress as a child (CTES, 17.0 vs. 5.4, p \u3c 0.001), compared to the urinary cluster. The systemic cluster also reported more intense bladder pain (3.3 vs. 0.8, p = 0.002), more widespread distribution of pain (34.8% vs. 4.0%, p = 0.009). The systemic cluster had worse urinary incontinence (ICIQ-UI, 14.0 vs. 10.7, p = 0.028) and quality of life (SF-36, 43.7 vs. 74.6, p \u3c 0.001). The two clusters were indistinguishable by their urgency symptoms (ICIQ-OAB, OAB-q, IUSS, 0-10 ratings). The two OAB clusters were different from patients with IC/BPS (worse urgency incontinence and less pain). CONCLUSIONS: The OAB population is heterogeneous and symptom-based clustering has identified two clusters of OAB patients (a systemic cluster vs. a bladder cluster). Understanding the pathophysiology of OAB subtypes may facilitate treatments

Comparison of monophasic with single and dual capacitor biphasic waveforms for nonthoracotomy canine internal defibrillation

AbstractMonophasic and single capacitor and dual capacitor biphasic truncated exponential shocks were tested in pentobarbital-anesthetized dogs with use of a nonthoracotomy internal defibrillation pathway consisting of a right ventricular catheter electrode and a subcutaneous chest wall patch electrode. Seven dogs weighing 20.2 ± 0.5 kg were utilized. Monophasic pulses of 10 ms duration were compared with three biphasic pulses. All biphasic waveforms had an initial positive phase (PI) followed by a terminal negative phase (P2) and the total duration of Pt Plus P2 was 10 ms. The dual capacitor biphasic waveform (PI 9 ms, P2 1 ms) had equal initial voltages of Pt and P2. Two simulated single capacitor biphasic waveforms were also tested, the first designed to minimize the magnitude of P2 (P19 ms, P21 ms with initial voltage of P2 equal to 0.3 of the initial voltage of P1) and the second to maximize P2 (PI 5 ms, P2 5 ms with initial voltage of P2 = 0.5 PI).Alternating current was used to induce ventricular fibrillation and four trials of eight initial voltages from 100 to 800 V were performed for each of the four waveforms. Stepwise logistic regression was utilized to construct curves relating probability of successful defibrillation and energy.In the logistic model, the dual capacitor biphasic and single capacitor biphasic waveforms that maximized P2 were associated with significantly (p < 0.001) lower energy requirements for defibrillation than those of the monophasic waveform. The single capacitor biphasic waveform that minimized P2 was not significantly better than the monophasic waveform. The biphasic waveforms associated with the lowest energy requirements for defibrillation were characterized by a higher P2/PI energy ratio.These results demonstrate that single capacitor biphasic waveforms can be constructed that are superior to similar duration monophasic waveforms and comparable with some dual capacitor biphasic waveforms. The relative magnitude of PI and P2 appears to be an important determinant of defibrillation efficacy

High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.

To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a

Laparoscopic cytoreductive nephrectomy is associated with significantly improved survival compared with open cytoreductive nephrectomy or targeted therapy alone

The aim of the present study was to compare the survival outcomes for patients with metastatic renal cell carcinoma (mRCC) who underwent laparoscopic cytoreductive nephrectomy (CN) vs. open CN vs. targeted therapy (TT) alone at our institution. A retrospective chart review was performed at our institution for patients who underwent CN prior to TT (laparoscopic, n=48; open, n=48) or who were deemed unfit for surgery and received TT alone (n=36), between January 2007 and December 2012. Kaplan-Meier estimated survival and Cox proportional hazards analyses were performed. Laparoscopic CN was associated with significantly longer survival compared with open CN or TT alone (median survival 24 vs. \u3c12 months, respectively; P\u3c0.01). On multivariate analysis, laparoscopic CN was an independent predictor of survival [hazard ratio (HR)=0.48, P\u3c0.01), controlling for preoperative risk factors, while survival was similar between open CN and TT alone (HR=0.85, P=0.54). In our experience, laparoscopic CN appears to be a significant predictor of survival in mRCC. Selection bias of the surgeon for patients with improved survival may account for clinical variables that were otherwise difficult to quantify. For patients who were not candidates for laparoscopic CN, open CN did not confer a survival benefit over TT alone, while it was associated with increased morbidity

Semileptonic decays of light quarks beyond the Standard Model

We describe non-standard contributions to semileptonic processes in a model independent way in terms of an SU(2)_L X U(1)_Y invariant effective lagrangian at the weak scale, from which we derive the low-energy effective lagrangian governing muon and beta decays. We find that the deviation from Cabibbo universality, \Delta_CKM = |V_ud|^2 + |V_us|^2 + |V_ub|^2 - 1, receives contributions from four effective operators. The phenomenological bound of \Delta_CKM = -1E-4 +- 6E-4 provides strong constraints on all four operators, corresponding to an effective scale greater than 11 TeV (90% CL). Depending on the operator, this constraint is at the same level or better then the Z pole observables. Conversely, precision electroweak constraints alone would allow universality violations as large as \Delta_CKM = -0.01 (90% CL). An observed nonzero \Delta_CKM at this level could be explained in terms of a single four-fermion operator which is relatively poorly constrained by electroweak precision measurements.Comment: 23 pages, 1 table and 5 eps figure

Degradation of communal rangelands in South Africa: towards an improved understanding to inform policy

In South Africa, the relative extent of range degradation under freehold compared to communal tenure has been strongly debated. We present a perspective on the processes that drive rangeland degradation on land under communal tenure. Our findings are based on literature as well as extensive field work on both old communal lands and ‘released’ areas, where freehold farms have been transferred to communal ownership. We discuss the patterns of degradation that have accompanied communal stewardship and make recommendations on the direction policy should follow to prevent further degradation and mediate rehabilitation of existing degraded land.Keywords: communal rangelands, land degradation, rehabilitation, social systemsAfrican Journal of Range &amp; Forage Science 2013, 30(1&amp;2): 57–6

Reevaluation of the role of nuclear uncertainties in experiments on atomic parity violation with isotopic chains

In light of new data on neutron distributions from experiments with antiprotonic atoms [ Trzcinska {\it et al.}, Phys. Rev. Lett. 87, 082501 (2001)], we reexamine the role of nuclear-structure uncertainties in the interpretation of measurements of parity violation in atoms using chains of isotopes of the same element. With these new nuclear data, we find an improvement in the sensitivity of isotopic chain measurements to ``new physics'' beyond the standard model. We compare possible constraints on ``new physics'' with the most accurate to date single-isotope probe of parity violation in the Cs atom. We conclude that presently isotopic chain experiments employing atoms with nuclear charges Z < 50 may result in more accurate tests of the weak interaction.Comment: 6 pages, 1 fig., submitted to Phys. Rev.

KatharoSeq Enables High-Throughput Microbiome Analysis from Low-Biomass Samples

Minich JJ, Zhu Q, Janssen S, et al. KatharoSeq Enables High-Throughput Microbiome Analysis from Low-Biomass Samples. mSystems. 2018;3(3):e00218-17

901-21 Percutaneous Vascular Surgery: Suture Mediated Percutaneous Closure of Femoral Artery Access Site Following Coronary Intervention

A new device (prostarTm, Perclose, Inc.) was developed to close femoral artery access sites percutaneously following coronary interventions in fully anticoagulated patients. The catheter deploys four needles with two pairs of sutures around the hole of femoral artery access sites. The sutures are then tied to close the arteriotomy site mechanically to achieve immediate hemostasis. As a pilot phase, the device was tested in six centers. The device was used immediately following coronary intervention in 91 access sites. Despite an average ACT at the time of the procedure of &gt;300 seconds, immediate complete hemostasis was achieved in 82 sites (90%). The devices were not appropriately positioned in 8 cases and procedures were aborted followed by reinsertion of a sheath or manual compression. Two patients (2.2%) required surgical repair of the femoral artery; one with device mechanical failure and one with bleeding from the initial puncture site in the posterior wall despite successful closure of the sheath site in the front wall. There were no AV fistulae or pseudoaneurysms requiring surgery and no infection, distal embolism or need for blood transfusion.In conclusion, this pilot study suggests that this suture mediated closure device appears to provide safe and effective hemostasis at the femoral access site in fully anticoagulated patients following coronary interventions