Electrically Enhanced Boron Removal from Silicon Using Slag

An approach to enhance silicon refining using slag has been developed. The enhancement of the process was carried out by applying electrical potential difference across the slag and the silicon phase. This resulted in a shift in the apparent equilibrium in favor of higher partition ratio for the impurities. The application of electrical potential difference also enhanced the mass transfer rate increasing the overall kinetics of the process. This has been demonstrated in laboratory experimentations for the removal of boron from silicon-boron melts using slag. A CaO-SiO₂-Al₂O₃ slag was reacted with Si-B melt at 1823 K (1550 °C). Electrical potential differences were applied through graphite rods immersed in each of the liquid phase. The results showed that the apparent B-partition ratio and the apparent slag mass transfer coefficient were increased by a factor of 1.2 and 1.4, respectively, when a potential difference of 3 V was applied to the phases. The technique has the potential to be used for improving the existing slag refining process by increasing the overall kinetics and the slag capacity to absorb the impurities.     

27—A STUDY OF FLAME-RESIST TREATMENTS OF WOOL BY INORGANIC TIN CHEMICALS

An investigation is reported into the mode of action of two commercial flame-resist treatments for wool containing inorganic tin salts. For stannic chloride–ammonium bifluoride formulations, it is shown by ^119mSn Mössbauer spectroscopy that the tin species initially exhausted onto the fabric (SnF₅OH^2?) is chemically different from that observed after washing (SnO₂). A similar study of the potassium hexafluorozirconate–stannous chloride–hydrochloric acid system indicated that SnO₂ was formed, even before washing, and that no tin (II) species remained. The flame-resist properties of several other tin (IV) salts on wool are also reported. Stannic oxide itself appears to be ineffective as a flame-retardant for wool.     

Blood lead (Pb) levels: Further evidence for an environmental mechanism explaining the association between socioeconomic status and psychophysiological dysregulation in children.

Objective: The authors recently reported that blood lead (Pb) was a significant mediator for the positive association between socioeconomic status (SES) and peripheral vascular responses to acute stress in children (B. B. Gump et al., 2007). The present study considers the possibility that Pb may also mediate an association between SES and cortisol responses to acute stress. Design: Early childhood Pb exposure was tested as a mediator for cross-sectional associations between SES and cortisol responses. Main Outcome Measures: The primary outcome was cortisol responses to acute stress in 9.5-year-old children (N = 108). Results: Lower family income was associated with significantly greater cortisol levels following an acute stress task. A mediational analysis confirmed that Pb was a significant mediator for this association. Conclusion: These results reaffirm the importance of considering the chemical environment as well as social and psychological environment when evaluating psychophysiological effects of low SES. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identifying the dominant failure mode in the hot extrusion tooling used to forge nickel based superalloy

The dies used in the extrusion of nickel based super alloys are subject to severe mechanical and thermal stresses, resulting in shortened life and high manufacturing costs. It is necessary to understand the dominant damage mode in order to guide improvements for increased tool life. The operation under examination consists of the hot extrusion of a nickel based superalloy using nitrided hot work tool steel, glassed workpieces and graphite lubrication. The investigation was conducted through a combination of metallurgical analysis, metrology and finite element analysis. Out of the damage modes observed under these conditions, the plastic deformation of the substrate was found to be the cause for tool failure. This paper discusses the relationship between plastic deformation of the substrate and the formation of scoring marks, which fail the die.     

Chronic illness, pain and health behaviors of community behavioral health clients.

Persons with comorbid medical disorders, along with substance use disorders and mental illness, present complex treatment needs that are seldom addressed. Chronic physical illness negatively affects treatment participation and retention, decreasing effectiveness. Studies documenting higher medical morbidity and mortality in such persons have long been available. Less is known about their health behaviors. Respondents (n = 418) at a community behavioral health center were surveyed for prevalence of illness, pain, health behaviors, and interest in lifestyle change. A total of 73% reported at least one chronic health problem, and nearly half rated their health between fair and very poor. Most reported at least one negative health indicator or behavior (e.g., smoking). Encouragingly, nearly 50% desired lifestyle changes including smoking cessation, exercise, and stress management. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confocal laser scanning ophthalmoscope and spherical harmonics used as a possible aid to detect glaucoma

We present a procedure whereby the confocal laser scanning ophthalmoscope can be used to extract information about the three-dimensional structure of the central excavated area or the cup of the optic nerve head of the eye. The data are analyzed in terms of spherical harmonics. It is hypothesized that the shape of the cup of the optic nerve head for a normal eye can be parameterized by a specific set of spherical harmonic coefficients and is different from the set of coefficients describing a glaucomatous eye. The sets of coefficients are analyzed by using multivariate statistics and can in turn be used to classify new observations. Preliminary results indicate that there are significant differences in the coefficients and that the procedure might have potential as a diagnostic aid for the detection or the screening of glaucoma.     

Observations of the Effects of Oxide Skins on the Oscillations of Electromagnetically Levitated Metal Droplets

The surface tensions of liquid metals can be derived from measurements of the natural oscillation frequencies of levitated drops through the Rayleigh relation, In general, during terrestrial measurements, a spectrum consisting of three to five dominant oscillation frequencies (in the range of 30 to 60 Hz) are found, rather than the single one predicted by Rayleigh, due to deformation of the drop shape by gravity and the supporting magnetic field. Cummings and Blackburn have derived a correction factor to align the measured frequencies with the Rayleigh frequency, which has been shown to hold through micro-gravity experiments by Egry et al., for the majority of metals that have a liquid surface. Work at the NPL on more complex, commercial alloys has found that, in some cases, oscillation frequencies may be split into more complex spectra exhibiting seven to nine oscillation frequencies. This has been attributed to formations of oxide from the metal collecting on the surface of the droplet. Observations of the frequency spectra and high speed video images of the levitated drops are discussed.     

T lymphocyte responses to anti-neutrophil cytoplasmic autoantibody (ANCA) antigens are present in patients with ANCA-associated systemic vasculitis and persist during disease remission

The cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel has been identified in the cardiac muscle of a number of mammalian species, including humans. The goal of this study was to begin quantifying the structural requirements necessary for arylaminobenzoate block of the CFTR channel. The cardiac cAMP-dependent Cl- current (ICl) was measured using the whole-cell arrangement of the patch-clamp technique in guinea pig ventricular myocytes during stimulation of protein kinase A with forskolin. At drug concentrations below the IC50 value for channel block, reduction of ICl by the arylaminobenzoates occurred in a strongly voltage-dependent manner with preferential inhibition of the inward currents. At higher drug concentrations, block of both the inward and outward ICl was observed. Increasing the length of the carbon chain between the benzoate and phenyl rings of the arylaminobenzoates resulted in a marked increase in drug block of the channel, with IC50 values of 47, 17, and 4 microM for 2-benzylamino-5-nitro-benzoic acid, 5-nitro-2-(2-phenylethylamino)-benzoic acid, and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), respectively. Increasing the carbon chain length further with the compound 5-nitro-2-(4-phenylbutylamino)-benzoic acid, caused no additional increase in the potency of drug block (IC50 = 4 microM). Inhibition of ICl by the arylaminobenzoates was modulated by the pH of the external solution; increasing the pH from 7.4 to 10.0 greatly weakened NPPB block, whereas decreasing the pH to 6.4 enhanced block. In addition, block of ICl was observed during intracellular dialysis of NPPB, and this action was not affected by raising the external pH.     

Postsurgical bile leaks: endoscopic obliteration of the transpapillary pressure gradient is enough

OBJECTIVES: Bile leaks are a well documented complication of biliary surgery, occurring more frequently with laparoscopic procedures. Endoscopic therapy with a long biliary endoprosthesis traversing the site of the leak is effective. We have evaluated the hypothesis that equalizing biliary and duodenal pressures with a short transpapillary stent is an equally effective therapy for bile leaks. METHODS: Thirty one consecutive patients presenting over a 52-month period with postsurgical bile leaks were evaluated. Patients had been treated with long endoprostheses (stents or nasobiliary tubes), sphincterotomy, or short transpapillary stents. The success, complication rate, need for additional therapy, and hospitalization time of each therapeutic approach were determined. RESULTS: Endoscopic therapy was successful in all 25 patients in whom a bile leak could be documented. The clinical success, need for radiological drainage, length of hospitalization, and incidence of pancreatitis were similar for all methods of treatment. CONCLUSIONS: These results confirm that endoscopic therapy is highly successful in the treatment of postoperative bile leaks and suggest that the mechanism of healing is the equalization of bile duct and duodenal pressures, allowing flow of bile into the duodenum. The endoscopic placement of short transpapillary stents without sphincterotomy is a temporary, effective, and technically simple method of pressure equalization. This should be considered as the primary therapy for most postoperative bile leaks.