Language attitudes in an Egyptian discourse community

This study investigates language attitudes in an elite university in Egypt, addressing all codes spoken in the community: Fusha (Classical Arabic/Modern Standard Arabic), Egyptian Arabic, English and Egyptian Arabic-English code-switching. Some attitudinal research in the region has been conducted (e.g. Bentahila, 1983; Chakrani, 2011; Lawson & Sachdev, 2000), though most neglects to position the discourse community in larger society and uses limited methodological approaches. In this study, attitudes are interpreted with attention to prevailing language ideologies, including the notion of a standard language, tension between modernity and tradition and language as symbolic capitol. Overt and covert attitudes in terms of both status and solidarity were discerned through a questionnaire, a matched-guise study and group interviews. The discourse community was found to be close-knit, with members viewing themselves as distinct from the rest of Egyptian society. Participants all had a strong command of English, though they varied in Fusha proficiency. Mixed attitudes toward Fusha emerged, in terms of both prestige and importance for maintaining Egyptian/Arab identity. Egyptian Arabic ranked low for status traits, though the variety was ascribed covert prestige in terms of solidarity for males. English was viewed positively as a language of both status and solidarity. Though overt attitudes toward code-switching were ambivalent, covert attitudes toward code-switching were generally positive, a novel finding. This study offers a paradigm for detailed analysis of the language attitudes of a community. Further, it demonstrates the growing favor of English as a language of economic power and explores code-switching as a prestigious in-group language that allows negotiation of modern and traditional identities amongst the privileged classes in Egypt

The Role of Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma and Its Clinical Implications

Worldwide, more than 550, 000 new cases of head and neck squamous cell carcinoma (HNSCC) are estimated to occur annually, making it the sixth most common human malignancy. Since their discovery in 2007, cancer stem cells (CSCs) in HNSCC have garnered increased interest secondary to their properties of tumorigenicity, differenti- ation, proliferation, and self-renewal. CSCs are intrinsically more resistant to tradi- tional treatments such as radiation and chemotherapy, contributing to potential metastasis and recurrence of HNSCC. This chapter focuses first on normal head and neck stem cells, providing background for the discussion of a number of topics pertaining to the study of HNSCC CSCs including molecular biomarkers and clinical implications. Continued research to elucidate the properties of CSCs will undoubt- edly expand our knowledge surrounding the pathogenesis, metastasis, and relapse of HNSCC. Ultimately, a better understanding of CSC biomarkers, signaling pathways, and mechanisms of resistance will improve therapies and patient outcomes through targeted interventions

Differentiation of Murine Embryonic Stem Cells to Thyrocytes Requires Insulin and Insulin-like Growth Factor-1

[Abstract] The mechanisms controlling thyrocyte development during embryonic stem (ES) cell differentiation have only been partially elucidated, although previous studies have suggested the participation of thyroid stimulating hormone (TSH) in these processes. To further define the role of TSH in this context, we have studied a murine ES cell line in which green fluorescent protein (GFP) cDNA is targeted to the TSH receptor (TSHR) gene, linking the expression of GFP to the transcription of the endogenous TSHR gene. We demonstrate that, in the initial stages of embryoid body formation, activin A and TSH induce the differentiation of definitive endoderm and thyrocyte progenitors expressing Sox17, Foxa2, and TSHR. These thyrocyte progenitors are then converted into cellular aggregates that, in the presence of insulin and IGF-1, further differentiate into mature thyroglobulin-expressing thyrocytes. Our data suggest that, despite the fact that TSH is important for the induction and specification of thyrocytes from ES cells, insulin and IGF-1 are crucial for thyrocyte maturation. Our method provides a powerful in vitro differentiation model for studying the mechanisms of early thyrocyte lineage development.United States. National Institutes of Health; DK06805

Analysis of siderophore production by Rhizobium meliloti 220-5

A universal chemical assay (Schwyn and Neilands , 1987) was used to detect the production of siderophore in a range of rhizobacterial strains. Siderophore production was found to be strain specific In Rhizobium. The product ion of siderophore by Rhizobium meliloti 220-5 was examined in detail. Using the universal assay to test samples taken during growth of the bacterium in an iron deficient medium, it was established that product ion of the siderophore commenced at the onset of exponent ial growth. The cell free supernatant of R.meliloti 220-5 grown under iron deficient conditions and shown to contain a siderophore, was tested for the presence of catechol or hydroxamate groups. Neither group was detec ted.The cell free supernatant of R.meliloti 220-5 grown under iron deficient conditions and shown to contain a siderophore, was tested for the presence of catechol or hydroxamate groups. Neither group was detected.The cell free supernatant of R.meliloti 220-5 grown under iron deficient conditions and shown to contain a siderophore, was tested for the presence of catechol or hydroxamate groups. Neither group was detected. Using a phenol/chloroform extraction procedure the siderophore was isolated from low iron supernatants and purifie d by ion-exchange chromatography. IR spectra confirmed that the siderophore was neither catecholnor hydroxamate in nature. This indicates that it belongs to a third class of siderophores typified by rhizo bactin from R.meliloti DM4 (Smith and Neilands, 1984). Mutants o f R.meliloti 220-5 and R.meliloti 2011 d e f e c t iv e in the production of siderophore were isolated following transposon mutagenesis with Tn5-mob. The genomic sequence conta ining the transposon from R.meliloti 220-5-1 was cloned into pUC19 and used to screen a cosmid bank of R.meliloti 2011. Two cosmids hybridising were investigated. One cosmid, cosmid 3, complemented the mutation in R.meliloti 220-5-1. When the other mutants were tested for complementation by cosmid 3, the complementation pattern in dicated that cosmid 3 harbours more than one gene involved in the siderophore b io s yn thesis. The number of siderophore genes carried on this cosmid remains to be determined. SDS-polyacrylamide gelelec trophoresis of outer membrane proteins prepared from iron deficient cultures identified the presence, in R.meliloti 220-5, of two low iron induced proteins of 72,000 and 78,000 daltons. These induced prote ins were cut from prepa rative SDS-PAGE gels and used as antigens to raise polyclonal antibodies. Serum collected from the injectedrat was tested for the antibody by Western blot analysis

Attachment and Relationship Satisfaction as Moderators of the Relationship Between Female Repair Attempt Behavior and Couple Emotional Flexibility During Marital Conflict

The purpose of this study was to examine husbands� and wives� reports of attachment-related anxiety, attachment-related avoidance, and relationship satisfaction as moderators of the relationship between wives� self-reported repair attempt behaviors and couples� emotional flexibility during conversations regarding past hurts in their relationships. Participants consisted of 23 couples between 20 and 60 years of age who had been married no less than six months and were within their first marriage. Couples completed measures of relationship satisfaction, repair attempt behaviors, and attachment, followed by discussing past hurts in their marriages. Partners then reported continuous affect responses while watching a video of their discussions regarding past hurts, which revealed their levels of emotional flexibility during these difficult conversations. A series of hierarchical regression analyses were used to determine influential trends of moderation. Though analyses yielded non-significant results, findings revealed that the husbands� reports had an overall greater moderating impact than the wives� reports, and that husbands� satisfaction exerted a substantially greater predictive influence on the relationship between wives� self-reported repairing behaviors and couples� emotional flexibility when discussing past hurts than other variables. Clinical implications for couples� therapy and recommendations for future research on repair attempts and positive sentiment override are discussed.Human Development & Family Scienc

Effect of an external field on the reversible reaction of a neutral particle and a charged particle in three dimensions. II. Excited-state reaction

The excited-state reversible reaction of a neutral particle and a charged particle in an external electric field is studied in three dimensions. This work extends the previous investigation for the ground-state reaction [S. Y. Reigh et al., J. Chem. Phys. 129, 234501 (2008)] to the excited-state reaction with two different lifetimes and quenching. The analytic series solutions for all the fundamental probability density functions are obtained with the help of the diagonal approximation. They are found to be in excellent agreement with the exact numerical solutions of anisotropic diffusion-reaction equations. The analytical solutions for reaction rates and survival probabilities are also obtained. We find that the long-time kinetic transition from a power-law decrease to an exponential increase can be controlled by the external field strength or excited-state decay rates or both. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3394894open

Diffusiophoretically induced interactions between chemically active and inert particles

In the presence of a chemically active particle, a nearby chemically inert particle can respond to a concentration gradient and move by diffusiophoresis. The nature of the motion is studied for two cases: first, a fixed reactive sphere and a moving inert sphere, and second, freely moving reactive and inert spheres. The continuum reaction-diffusion and Stokes equations are solved analytically for these systems and microscopic simulations of the dynamics are carried out. Although the relative velocities of the spheres are very similar in the two systems, the local and global structures of streamlines and the flow velocity fields are found to be quite different. For freely moving spheres, when the two spheres approach each other the flow generated by the inert sphere through diffu- siophoresis drags the reactive sphere towards it. This leads to a self-assembled dimer motor that is able to propel itself in solution. The fluid flow field at the moment of dimer formation changes direction. The ratio of sphere sizes in the dimer influences the characteristics of the flow fields, and this feature suggests that active self-assembly of spherical colloidal particles may be manipulated by sphere-size changes in such reactive systems

A two-fluid model for locomotion under self-confinement

The bacterium Helicobacter pylori causes ulcers in the stomach of humans by invading mucus layers protecting epithelial cells. It does so by chemically changing the rheological properties of the mucus from a high-viscosity gel to a low-viscosity solution in which it may self-propel. We develop a two-fluid model for this process of swimming under self-generated confinement. We solve exactly for the flow and the locomotion speed of a spherical swimmer located in a spherically symmetric system of two Newtonian fluids whose boundary moves with the swimmer. We also treat separately the special case of an immobile outer fluid. In all cases, we characterize the flow fields, their spatial decay, and the impact of both the viscosity ratio and the degree of confinement on the locomotion speed of the model swimmer. The spatial decay of the flow retains the same power-law decay as for locomotion in a single fluid but with a decreased magnitude. Independent of the assumption chosen to characterize the impact of confinement on the actuation applied by the swimmer, its locomotion speed always decreases with an increase in the degree of confinement. Our modeling results suggest that a low-viscosity region of at least six times the effective swimmer size is required to lead to swimming with speeds similar to locomotion in an infinite fluid, corresponding to a region of size above ≈25μm for Helicobacter pylori.This work was funded in part by the Isaac Newton Trust, Cambridge, and by the European Union through a Marie Curie CIG Grant and a ERC Consolidator Grant