Helium Leak Measurements Using CO2 as a Carrier

Detection delay defects are omitted by using helium mass spectrometer leak detector combined with several known procedures. Technique combines carbon dioxide purging, cryogenic separating helium accumulation, and use of carbon dioxide as carrier gas

Dismantling Neutrality: Cultivating Antiracist Writing Center Ecologies

There is a temptation when working in writing centers, composition classrooms, and other language-focused sites for us to say that we want students to be stronger communicators, stronger writers, stronger speakers. Yet, in the writing center at least, this notion of “stronger” is often understood as adherence to the rules of “Standard American English” (SAE). There are other names for this so-called standard: the Language of Wider Communication (LWC), the dominant discourse, academic discourse, and so on. We who work in writing centers often convince ourselves that because we are focused on language, then we are free from bias, and that language and literacy are neutral skills. We want to help students, after all. We tell them that, yes, you’ve been writing for years now, but we can teach you to write better. Or, and somehow this seems worse to me, you have a home language, but that language is inadequate for your new setting. In this article, I explore the potential complications of running writing centers at minority serving institutions (MSI), with special attention to Hispanic Serving Institutions (HSI) and how thinking of writing centers as ecologies can provide keener insight into the real work of writing centers.University Writing Cente

Otra mirada a la dramaturgia de Emilio Carballido

Artículo número 9 de la Sección Tema. 12 páginas. tyvllvEl presente artículo busca reconocer en la dramaturgia de Emilio Carballido (1925-2008) elementos del Teatro político y Teatro documental para reconfigurar la visión que los nuevos dramaturgos y artistas escénicos en formación pueden generar sobre la misma, ya que su diversidad y vigencia se muestran tanto en los temas como en la forma en que se articulan. Lo anterior en dos obras dramáticas: ¡Silencio pollos pelones ya les van a echar su máiz! y Un pequeño día de ira.This article seeks to recognize in the dramaturgy of Emilio Carballido (1925-2008) elements of political theater and documentary theater to reconfigure the vision that new playwrights and stage artists in training can generate about it, since its diversity and validity are shown both in the themes and in the way they are articulated. The above in two dramatic works: ¡Silencio pollos pelones ya les van a echar su máiz! and Un pequeño día de ira

Hydrogen sulfide pathway and skeletal muscle: an introductory review.

The presence of the H2 S pathway in skeletal muscle (SKM) has recently been established. SKM expresses the three constitutive H2 S-generating enzymes in animals and humans, and it actively produces H2 S. The main, recognized molecular targets of H2 S, that is, potassium channels and PDEs, have been evaluated in SKM physiology in order to hypothesize a role for H2 S signalling. SKM dysfunctions, including muscular dystrophy and malignant hyperthermia, have also been evaluated as conditions in which the H2 S and transsulfuration pathways have been suggested to be involved. The intrinsic complexity of the molecular mechanisms involved in excitation-contraction (E-C) coupling together with the scarcity of preclinical models of SKM-related disorders have hampered any advances in the knowledge of SKM function. Here, we have addressed the role of the H2 S pathway in E-C coupling and the relative importance of cystathionine β-synthase, cistathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase in SKM diseases

Treatment of oil-water emulsion from the machinery industry by Fenton’s reagent

An oil–water emulsion from the machinery industry was treated using Fenton\u27s reagent. The objective was to reduce the high chemical oxygen demand (COD) of this waste stream so that it would meet the COD effluent limit of Chinese Standard JS-7740-95. The optimal [H2O2]/[Fe2+] ratio for COD removal was 3. An orthogonal experimental design was developed based on the optimal [H2O2]/[Fe2+] ratio to evaluate the significance of four parameters relevant to the treatment process, namely, H2O2 dosage, initial pH, oxidation time and coagulation pH. The influence of the four parameters on COD removal efficiency decreased as follows: H2O2 dosage \u3e oxidation time \u3e coagulation pH \u3e initial pH. The COD removal efficiency was further investigated based on the most important single-factor parameter, which was H2O2 dosage, as discovered in the orthogonal test. A well-fitted empirical correlation was obtained from the single-factor analysis and up to 98% COD removal was attained using 50 mM H2O2. Using the doses and conditions identified in this study, the treated oil–water emulsion can be discharged according to Chinese Standard JS-7740-95

Ethanol induces cell-cycle activity and reduces stem cell diversity to alter both regenerative capacity and differentiation potential of cerebral cortical neuroepithelial precursors

BACKGROUND: The fetal cortical neuroepithelium is a mosaic of distinct progenitor populations that elaborate diverse cellular fates. Ethanol induces apoptosis and interferes with the survival of differentiating neurons. However, we know little about ethanol's effects on neuronal progenitors. We therefore exposed neurosphere cultures from fetal rat cerebral cortex, to varying ethanol concentrations, to examine the impact of ethanol on stem cell fate. RESULTS: Ethanol promoted cell cycle progression, increased neurosphere number and increased diversity in neurosphere size, without inducing apoptosis. Unlike controls, dissociated cortical progenitors exposed to ethanol exhibited morphological evidence for asymmetric cell division, and cells derived from ethanol pre-treated neurospheres exhibited decreased proliferation capacity. Ethanol significantly reduced the numbers of cells expressing the stem cell markers CD117, CD133, Sca-1 and ABCG2, without decreasing nestin expression. Furthermore, ethanol-induced neurosphere proliferation was not accompanied by a commensurate increase in telomerase activity. Finally, cells derived from ethanol-pretreated neurospheres exhibited decreased differentiation in response to retinoic acid. CONCLUSION: The reduction in stem cell number along with a transient ethanol-driven increase in cell proliferation, suggests that ethanol promotes stem to blast cell maturation, ultimately depleting the reserve proliferation capacity of neuroepithelial cells. However, the lack of a concomitant change in telomerase activity suggests that neuroepithelial maturation is accompanied by an increased potential for genomic instability. Finally, the cellular phenotype that emerges from ethanol pre-treated, stem cell depleted neurospheres is refractory to additional differentiation stimuli, suggesting that ethanol exposure ablates or delays subsequent neuronal differentiation