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    Fluorescence studies on the Ca2+ and Zn2+ binding properties of the α-subunit of bovine brain S-100a protein

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    AbstractThe single cysteine on the α-subunit of bovine brain S-100a protein has been modified with the thiol specific probe, Acrylodan. When the labelled apoprotein was excited at 380 nm the fluorescence emission maximum was centered at 484 ± 2 nm, suggesting that the probe is in a fairly hydrophobic environment. Addition of Ca2+ to the protein caused the emission maximum to undergo a red shift to 504 ± 2 nm, implying that the fluorophore is now more exposed to the solvent. Zn2+, when added to the protein, induced only a small perturbation and the emission maximum shifted to 481 ± 2 nm. Ca2+ was able to perturb the fluorophore in the presence of Zn2+. 2-p-Toluidinylnaphthalene-6-sulfonate (TNS)-labelled α-subunit when excited at 345 nm exhibited very little fluorescence in the absence of Ca2+. Addition of Ca2+ resulted in an increase in TNS fluorescence accompanied by a blue shift of the emission maximum to 445 ± 1 nm indicating that the probe in the presence of Ca2+ moves to a hydrophobic domain. The fact that Ca2+ and Zn2+ can perturb the labelled sulfhydryl group in the presence of each other clearly demonstrates that the binding sites for the two metal ions must be different on the α-subunit as well as on the S-100a protein

    Preservice Teachers’ Views about e-book and Their Levels of Use of e-books

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    AbstractThe purpose of this study was to determine the views of preservice teacher about e-books and the level of their general knowledge about these kinds of technological tools. The subjects in this study consisted of 543 (310 females and 233 males) students. In line with the purpose of this study, both qualitative and quantitative methods were applied. The results demonstrated that the use of e-books increased in accordance with the students’ levels. It was found out that the general knowledge levels of the social sciences students about e-books were lower when compared to the students from the departments of Science, Mathematics and Foreign Languages. It was seen that 19,15% of the students did not make any preference between e-books and conventional printed books while 54,88% of them preferred printed books and 25,97% them e-books

    SOX15 Governs Transcription in Human Stratified Epithelia and a Subset of Esophageal Adenocarcinomas

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    Background & AimsIntestinal metaplasia (Barrett’s esophagus, BE) is the principal risk factor for esophageal adenocarcinoma (EAC). Study of the basis for BE has centered on intestinal factors, but loss of esophageal identity likely also reflects the absence of key squamous-cell factors. As few determinants of stratified epithelial cell-specific gene expression have been characterized, identifying the necessary transcription factors is important.MethodsWe tested regional expression of mRNAs for all putative DNA-binding proteins in the mouse digestive tract and verified the esophagus-specific factors in human tissues and cell lines. Integration of diverse data defined a human squamous esophagus-specific transcriptome. We used chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) to locate transcription factor binding sites, computational approaches to profile the transcripts in cancer data sets, and immunohistochemistry to reveal protein expression.ResultsThe transcription factor Sex-determining region Y-box 15 (SOX15) is restricted to esophageal and other murine and human stratified epithelia. SOX15 mRNA levels are attenuated in BE, and its depletion in human esophageal cells reduces esophageal transcripts significantly and specifically. SOX15 binding is highly enriched near esophagus-expressed genes, indicating direct transcriptional control. SOX15 and hundreds of genes coexpressed in squamous cells are reactivated in up to 30% of EAC specimens. Genes normally confined to the esophagus or intestine appear in different cells within the same malignant glands.ConclusionsThese data identify a novel transcriptional regulator of stratified epithelial cells and a subtype of EAC with bi-lineage gene expression. Broad activation of squamous-cell genes may shed light on whether EACs arise in the native stratified epithelium or in ectopic columnar cells

    Author index for volume 51

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    A colo-urachal-cutaneous fistula in an 88-year-old male

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    AbstractIntroductionUrachus anomalies are remnants of the urachus, an embryonic connection between the fetal bladder and umbilicus. These anomalies usually remain asymptomatic but can cause symptoms in case of infection. An extremely rare complication of symptomatic urachal remnants is fistulizing to adjacant viscera. We describe the first case of diverticulitis associated sigmoid-urachal-cutaneous fistula.Case reportAn 88-year-old male visited the outpatient clinic with intermittent bleeding and gassy discharge from his umbilicus. Examination showed a normal looking umbilicus with a small fissure at the bottom in which a 10cm probe could be inserted. Laparotomy revealed a fistula extending from the umbilicus to a pus filled cyst superior to the bladder. A second fistula between the cyst and a mid-sigmoid diverticulum was identified. The involved sigmoid segment was resected. Pathological examination demonstrated no malignancy.DiscussionUrachal remnants are extremely rare in adults. They typically present with abdominal pain or palpable masses. Additional imaging can aid the diagnostic process.ConclusionDue to the risk of recurrence and malignant transformation complete surgical excision of urachal anomalies is the treatment of choice. This can be done in a 1-step or 2-step procedure

    Interpolation norms between row and column spaces and the norm problem for elementary operators

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    AbstractFor the class of transformers acting as X→∫ΩAtXBtdμ(t) on the space of bounded Hilbert space operators we give formulae for its norm on the Hilbert–Schmidt class(1)X→∫ΩAtXBtdμ(t)B(C2(H))=limn→∞∫Ω2ntr∏k=1nAtn+1-k∗Asn+1-ktr∏k=1nBskBtk∗∏k=1ndμ(sk)dμ(tk)2n,whenever ∫Ω‖At‖p‖Bt‖pdμ(t)<∞ for some p>0. We also estimate from below its norm on the other Schatten classes. This answers a question of characterizing (θ=)12 interpolation norm between column and row space norm for operator valued functions, with the discrete case providing the solution of the norm problem for elementary operators acting on the Hilbert–Schmidt class

    A novel mode converter based on a 2D dielectrically chiral photonic structure

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    AbstractWe designed a novel two-dimensional periodic chiral waveguide structure, which can achieve complete TE-TM mode conversion. We study the effect of the relevant parameters of structure on the conversion efficiency and confirm that in a certain range, the mode conversion has a rather high efficiency
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