Solvent Extraction of Yttrium: Modeling the Rate Coefficient, Loading Ratio and Stoichiometric Ratio

Yttrium was extracted from acidic solutions using di(2-ethylhexyl) phosphate (DEHPA) for three studies. In doing so, three process parameters were analyzed: extraction rate coefficient, loading ratio, and stoichiometric ratio.The first parameter, extraction rate coefficient, was modeled for a mixer-settler where the organic phase was recycled and the extractant concentration varied. The extraction rate coefficient increased as the recycle ratio increased because recycling the organic phase increased the organic-to-aqueous volume ratio in the mixer and thus increased the interfacial area between phases. The extraction rate coefficient increased as the extractant concentration increased when the extractant concentration was low. However, at high extractant concentrations, the organic phase viscosity had increased due to high metal loading. The high viscosity lowered the organic-phase molecular diffusion and thus decreased the extraction rate coefficient.Based on process economics, it may be beneficial to conduct a process such that the second parameter, loading ratio, is maximized. This is most likely true for processes using costly extractants. A procedure to determine the maximum loading ratio and corresponding optimum extractant concentration for any solvent extraction process was presented. The previous study\u27s results were used for validation. To increase the loading ratio, operating nearer to the optimum extractant concentration was more effective than increasing the efficiency. An example was presented where although all processes operated at 90% efficiency, the only profitable process was the scenario operating at the optimum extractant concentration.The third parameter, stoichiometric ratio, was modeled for the equilibrium extraction of yttrium from hydrochloric acid. Although some authors have observed stoichiometric ratios less than the theoretical value of three, few have suggested a mechanism for the deviation from ideality. This study confirmed that the decrease was attributed to chloride ions complexing with yttrium ions to extract together into the organic phase. The overall equilibrium equation is described as a weighted average of two simultaneous equilibrium extractions. Increasing either the hydrochloric acid concentration or the yttrium feed concentration decreased the stoichiometric ratio, but the former had a more significant effect. The aqueous-phase activity coefficients provided only slight improvements in predicting the equilibrium conditions

Section 547(c)(2) of the Bankruptcy Code: The Ordinary Course of Business Exception Without the 45 Day Rule

This article will look at some of the principles set forth by case law and provide a more structured method of analyzing cases under section 547(c) (2). In addition, it will examine a few problem areas that are certain to arise in section 547(c) (2) litigation in the near future: (1) Does section 547(c) (2) now protect principal payments on long term debt?; and, (2) will section 547(c) (2) protect a payment to one creditor when all or nearly all other creditors were not paid during the preference period? But before doing so, a short explanation of the Code\u27s definition of preference and a look at the policy and history behind both preference law and the ordinary course exception is in order

Lower Extremity Passive Range of Motion in Community-Ambulating Stroke Survivors

Background: Physical therapists may prescribe stretching exercises for individuals with stroke to improve joint integrity and to reduce the risk of secondary musculoskeletal impairment. While deficits in passive range of motion (PROM) exist in stroke survivors with severe hemiparesis and spasticity, the extent to which impaired lower extremity PROM occurs in community-ambulating stroke survivors remains unclear. This study compared lower extremity PROM in able-bodied individuals and independent community-ambulatory stroke survivors with residual stroke-related neuromuscular impairments. Our hypothesis was that the stroke group would show decreased lower extremity PROM in the paretic but not the nonparetic side and that decreased PROM would be associated with increased muscle stiffness and decreased muscle length. Methods: Individuals with chronic poststroke hemiparesis who reported the ability to ambulate independently in the community (n = 17) and age-matched control subjects (n = 15) participated. PROM during slow (5 degrees/sec) hip extension, hip flexion, and ankle dorsiflexion was examined bilaterally using a dynamometer that measured joint position and torque. The maximum angular position of the joint (ANGmax), torque required to achieve ANGmax (Tmax), and mean joint stiffness (K) were measured. Comparisons were made between able-bodied and paretic and able-bodied and nonparetic limbs. Results: Contrary to our expectations, between-group differences in ANGmax were observed only during hip extension in which ANGmax was greater bilaterally in people post-stroke compared to control subjects (P ≤ 0.05; stroke = 13 degrees, able-bodied = −1 degree). Tmax, but not K, was also significantly higher during passive hip extension in paretic and nonparetic limbs compared to control limbs (P ≤ 0.05; stroke = 40 Nm, able-bodied = 29 Nm). Compared to the control group, Tmax was increased during hip flexion in the paretic and nonparetic limbs of post-stroke subjects (P ≤ 0.05, stroke = 25 Nm, able-bodied = 18 Nm). K in the nonparetic leg was also increased during hip flexion (P ≤ 0.05, nonparetic = 0.52 Nm/degree, able-bodied = 0.37 Nm/degree.) Conclusion: This study demonstrates that community-ambulating stroke survivors with residual neuromuscular impairments do not have decreased lower extremity PROM caused by increased muscle stiffness or decreased muscle length. In fact, the population of stroke survivors examined here appears to have more hip extension PROM than age-matched able-bodied individuals. The clinical implications of these data are important and suggest that lower extremity PROM may not interfere with mobility in community-ambulating stroke survivors. Hence, physical therapists may choose to recommend activities other than stretching exercises for stroke survivors who are or will become independent community ambulators

Speciation in the baboon and its relation to gamma-chain heterogeneity and to the response to induction of HbF by 5-azacytidine

In the baboon (Papio species), the two nonallelic gamma-genes produce gamma-chains that differ at a minimum at residue 75, where isoleucine (I gamma-chain) or valine (V gamma) may be present. This situation obtains in baboons that are sometimes designated as Papio anubis, Papio hamadryas, and Papio papio. However, in Papio cynocephalus, although the I gamma-chains are identical with those in the above mentioned types, the V gamma-chains have the substitutions ala----gly at residue 9 and ala----val at residue 23. The V gamma-chains of P. cynocephalus are called V gamma C to distinguish them from the V gamma A-chains of P. anubis, etc. A single cynocephalus animal has been found to have only normal I gamma-chains and I gamma C-chains (that is, glycine in residue 9, valine in 23, and isoleucine in 75). When HbF is produced in response to stress with 5-azacytidine, P. anubis baboons respond with greater production than do P. cynocephalus, and hybrids fall between. Minimal data on P. hamadryas and P. papio suggest an even lower response than P. cynocephalus. As HbF increases under stress, the ratio of I gamma to V gamma-chains changes from the value in the adult or juvenile baboon toward the ratio in the newborn baboon. However, it does not attain the newborn value. The V gamma A and V gamma C-genes respond differently to stress. In hybrids, the production of V gamma A- chains exceeds that of V gamma C-chains. A controlling factor in cis apparently is present and may be responsible for the species-related extent of total HbF production. It may be concluded that the more primitive the cell in the erythroid maturation series that has been subjected to 5-azacytidine, the more active is the I gamma-gene

Improvement in the quality of ultrasonic images by applying spatial composition methods and using phased array systems

La técnica de ultrasonidos de Phased Array (PA) se ha convertido en una herramienta para la Evaluación No Destructiva (END) por imágenes muy utilizada en el sector industrial. La técnica PA permite realizar deflexiones y enfocar el haz de ultrasonidos en diferentes profundidades dentro del material, mediante el control electrónico de cada uno de los N elementos que componen el transductor o array, facilitando la realización de diversos barridos para generar imágenes en distintos formatos. Las imágenes de PA resultan muy eficientes en la detección de los defectos, siempre que éstos tengan una orientación favorable a la dirección del haz. Por lo tanto, es requisito establecer correctamente el posicionamiento del transductor y la configuración del barrido. No obstante, existen inconvenientes adicionales, tales como las pérdidas de calidad e intensidad en las indicaciones a medida que la detección se realiza con ángulos elevados. En estos casos, siempre resulta conveniente hacer exploraciones desde distintas posiciones y con diferentes rangos angulares para obtener información con diversidad espacial. Este trabajo presenta la composición espacial y coherente de imágenes PA capturadas con distintas orientaciones y posiciones sobre la pieza, para ser combinadas en una única imagen compuesta. Se ha creado un algoritmo genérico capaz de realizar una conversión de barrido utilizando interpolación bilineal, lográndose una imagen final de mayor calidad y precisión en el análisis cuantitativo de las indicaciones. La propuesta ha sido validada sobre componentes y en materiales que pueden componer piezas de uso nuclear.The Phased Array Ultrasonic Technique (PAUT) has become a widely used imaging tool for the Nondestructive Testing in the industrial field. The PAUT allows making deflections and focusing the ultrasound beam at different depths within the material, through an electronic control of each one of the N elements that make up the array transducer. Thus, several electronic sweeps can be performed to obtain images in different formats. The PAUT imaging is very efficient in detecting flaws whenever they have a favorable orientation relative to the beam direction. Therefore, it is necessary to establish the transducer position and set-up the scanning correctly. Nevertheless, there are some drawbacks such as quality and intensity losses in the data when the detection is made at high angles. For these reasons, it is necessary to perform exploration from different positions using different angular ranges to obtain information with spatial diversity. This work presents the spatial and coherent compounding of PAUT images, which have been captured with different orientations and in different positions related to the explored volume, to produce a single image. A generic algorithm was developed for performing a scanning conversion using the bilinear interpolation, which allows obtaining a high quality final image and more accuracy in the quantitative analysis of indications. The proposal has been validated on components and materials that can compose pieces of nuclear use.Fil: Quirós, Dante Patricio. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto Sabato; ArgentinaFil: Brizuela, Jose David. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Desimone, Carlos Alberto. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto Sabato; ArgentinaFil: Ramirez Daneri, Maria Silvana. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comisión Nacional de Energía Atómica; Argentin

Cyclic-AMP regulates postnatal development of neural and behavioral responses to NaCl in rats

During postnatal development rats demonstrate an age-dependent increase in NaCl chorda tympani (CT) responses and the number of functional apical amiloride-sensitive epithelial Na+channels (ENaCs) in salt sensing fungiform (FF) taste receptor cells (TRCs). Currently, the intracellular signals that regulate the postnatal development of salt taste have not been identified. We investigated the effect of cAMP, a downstream signal for arginine vasopressin (AVP) action, on the postnatal development of NaCl responses in 19–23 day old rats. ENaC-dependent NaCl CT responses were monitored after lingual application of 8-chlorophenylthio-cAMP (8-CPT-cAMP) under open-circuit conditions and under ±60 mV lingual voltage clamp. Behavioral responses were tested using 2 bottle/24h NaCl preference tests. The effect of [deamino-Cys1, D-Arg8]-vasopressin (dDAVP, a specific V2R agonist) was investigated on ENaC subunit trafficking in rat FF TRCs and on cAMP generation in cultured adult human FF taste cells (HBO cells). Our results show that in 19–23 day old rats, the ENaC-dependent maximum NaCl CT response was a saturating sigmoidal function of 8-CPT-cAMP concentration. 8-CPT-cAMP increased the voltage-sensitivity of the NaCl CT response and the apical Na+ response conductance. Intravenous injections of dDAVP increased ENaC expression and γ-ENaC trafficking from cytosolic compartment to the apical compartment in rat FF TRCs. In HBO cells dDAVP increased intracellular cAMP and cAMP increased trafficking of γ- and δ-ENaC from cytosolic compartment to the apical compartment 10 min post-cAMP treatment. Control 19–23 day old rats were indifferent to NaCl, but showed clear preference for appetitive NaCl concentrations after 8-CPT-cAMP treatment. Relative to adult rats, 14 day old rats demonstrated significantly less V2R antibody binding in circumvallate TRCs. We conclude that an age-dependent increase in V2R expression produces an AVP-induced incremental increase in cAMP that modulates the postnatal increase in TRC ENaC and the neural and behavioral responses to NaCl

The Grizzly, February 28, 2019

To Squat or to Cluster? That is the Question • HEP Professor Goes on a Revelatory Journey • SUN Event Concludes Black History Month • Ursinus Makes Impressive List • Eye-Opening Experiences in Limerick, Ireland • Religion Battles Science in Agnes of God • Opinions: U.S.\u27s Nuclear Intervention in Japan was Justified / was not Justified • The Did You Guys Seriously Forget How Good I Am? Award: Courtney Cortese • Men\u27s Hoops Eliminated in CC Semifinal; Williams Jr. Ends Career as CC Record-Holder • New Lax Coach, Mercadante, off to Impressive Starthttps://digitalcommons.ursinus.edu/grizzlynews/1614/thumbnail.jp

Catheter-based intervention for pulmonary vein stenosis due to fibrosing mediastinitis: The Mayo Clinic experience

AbstractIntroductionFibrosing mediastinitis (FM) is a rare but fatal disease characterized by an excessive fibrotic reaction in the mediastinum, which can lead to life-threatening stenosis of the pulmonary veins (PV). Catheter-based intervention is currently the only viable option for therapy. However, the current literature on how best to manage these difficult cases, especially in regards to sequential interventions and their potential complications is very limited.MethodsWe searched through a database of all patients who have undergone PV interventions at the Earl H. Wood Cardiac Catheterization Laboratory in Mayo Clinic, Rochester. From this collection, we selected patients that underwent PV intervention to relieve stenosis secondary to FM.ResultsEight patients were identified, with a mean age of 41years (24–59years). Five were men, and three were women. Three patients underwent balloon angioplasty alone, and five patients had stents placed. The majority of patients had acute hemodynamic and symptomatic improvement. More than one intervention was required in five patients, four patients had at least one episode of restenosis, and four patients died within four weeks of their first PV intervention.ConclusionsWe describe the largest reported case series of catheter-based intervention for PV stenosis in FM. Although catheter-based therapy improved hemodynamics, short-term vascular patency, and patient symptoms, the rate of life-threatening complications, restenosis, and mortality associated with these interventions was found to be high. Despite these associated risks, catheter-based intervention is the only palliative option available to improve quality of life in severely symptomatic patients with PV stenosis and FM. Patients with PV stenosis and FM (especially those with bilateral disease) have an overall poor prognosis in spite of undergoing these interventions due to the progressive and recalcitrant nature of the disease. This underscores the need for further innovative approaches to manage this disease