Renorming spaces with greedy bases

We study the problem of improving the greedy constant or the democracy constant of a basis of a Banach space by renorming. We prove that every Banach space with a greedy basis can be renormed, for a given \vare>0, so that the basis becomes (1+\vare)-democratic, and hence (2+\vare)-greedy, with respect to the new norm. If in addition the basis is bidemocratic, then there is a renorming so that in the new norm the basis is (1+\vare)-greedy. We also prove that in the latter result the additional assumption of the basis being bidemocratic can be removed for a large class of bases. Applications include the Haar systems in $L_p[0,1]$, $1<p<\infty$, and in dyadic Hardy space $H_1$, as well as the unit vector basis of Tsirelson space

Modelling and validating three dimensional human normal cervix and cervical cancer tissues in vitro

Objective: The use of three dimensional in vitro systems in cancer research is a promising path for developing effective anticancer therapies. The aim of this study was to engineer a functional 3-D in vitro model of normal and cancerous cervical tissue. Methods: Normal epithelial and immortalized cervical epithelial carcinoma cell lines were used to construct 3-D artificial normal cervical and cervical cancerous tissues. De-epidermised dermis (DED) was used as a scaffold for both models. Morphological analyses were conducted by using haematoxylin and eosin staining and characteristics of the models were studied by analysing the expression of different structural cytokeratins and differential protein marker Mad1 using immunohistochemical technique. Results: Haematoxylin and eosin staining results showed that normal cervical tissue had multi epithelial layers while cancerous cervical tissue showed dysplastic changes. Immunohistochemistry staining results revealed that for normal cervix model cytokeratin 10 was expressed in the upper stratified layer of epithelium while cytokeratin 5 was expressed mainly in the middle and basal layer. Cytokeratin 19 was weakly expressed in a few basal cells. Cervical cancer model showed cytokeratin 19 expression in different epithelial layers and weak or no expression for cytokeratin 5 and cytokeratin 10. Mad1 expression was detected in some suprabasal cells. Conclusions: The 3-D in vitro models showed stratified epithelial layers and expressed the same types and patterns of differentiation marker proteins as seen in corresponding in vivo tissue in either normal cervical or cervical cancerous tissue. Findings imply that they can serve as functional normal and cervical cancer models

Nitrogenase activity associated with codium species from New Zealand marine habitats

Nitrogenase activity, measured as acetylene reduction, was recorded at rates up to 1028 nmol.h \g * dry weight for Codium adhaerens (Cabr.) Ag. var. convolutum Dellow and Codium fragile (Sur.) Hariot subsp. tomentosoides (Van Goor) Silva collected from New Zealand habitats. In both species the ability to reduce acetylene is invariably associated with the presence of a heterocystous blue-green alga, Calothrix sp., epiphytic or embedded in the Codium thallus. A highly significant (P < 0.001) correlation between heterocyst frequency and nitrogenase activity was found. Nitrogenase and net photosynthesis of the Codium-Calothrix system have different steady-state responses to light intensity, and the kinetics of the two processes also differ in that nitrogenase is slow to respond to illumination or darkening. Glucose additions to Codium did not significantly increase nitrogenase activity. Nitrogenase is relatively insensitive to oxygen tension over the range 0-1.0 atm (0-1.033 kgf.cnT2) and still occurs at 1.5 atm (1.55 kgf.cm"2); this condition is unique in all nitrogenase systems thus far reported. Collectively these facts suggest that Calothrix is the agent primarily responsible for nitrogenase activity in these Codium species

Modelling and validating three-dimensional human breast and cancerous human breast tissues in vitro

In this study three dimensional (3-D) in vitro models of normal breast and breast cancer tissues were developed to mimic closely the in vivo tissue microenvironment and therefore providing reliable models for in vitro studies as well as testing of novel cancer therapies. Normal and cancerous human breast cell lines were used to construct 3-D artificial tissues, where de-epidermalised dermis (DED) was used as a scaffold for both models. Morphological analyses were conducted using haematoxylin and eosin staining. Biomarkers including keratin 5 and 19 as well as α smooth muscle actin and mucin 1 were used to confirm and validate the reliability of the proposed models using immunohistochemical techniques. Findings suggest that the 3-D in vitro models described in this work can serve as functional models of both human normal and cancerous breast tissues. Multiple structures similar to ducts and lobules of human breast in vivo were observed in 3-D in vitro models by the use of H&E, some breast cancer colonies seen in the cancerous 3-D model were similar to the ducto-lobular structures observed in normal 3-D model of the breast but the former cells were more loosely connected, irregular and largely disorganized. The established 3-D in vitro model of normal breast showed the development of ducto-lobular structures composed of an inner cell layer which was stained positive with α mucin 1 antibody, a biomarker that is characteristic for luminal cells; and also an outer basal layer of cells that was stained positive for α smooth muscle actin, a biomarker of myoepithelial cells.. Keratin staining in 3-D in vitro models also resembled the pattern observed in vivo where keratin 5 was detected in both luminal and myoepithelial cells of normal breast model (NTERT cells), whereas keratin 19 was present in breast cancer model (C2321 cells). These 3-D models successfully recapitulate both normal and pathological tissue architecture of breast tissue and has the potential for various applications in the evaluation of breast cancer progression and treatment

Drinking water quality is unrelated to public vs. private ownership

Political Science & Politics, 40(3): pp. 449-451

Surgery in the era of the 'omics revolution

BACKGROUND: Surgery is entering a new phase with the revolution in genomic technology. Cheap, mass access to next‐generation sequencing is now allowing the analysis of entire human genomes at the DNA and RNA level. These data sets are being used increasingly to identify the molecular differences that underlie common surgical diseases, and enable them to be stratified for patient benefit. METHODS: This article reviews the recent developments in the molecular biology of colorectal, oesophagogastric and breast cancer. RESULTS: The review specifically covers developments in genetic predisposition, next‐generation sequencing studies, biomarkers for stratification, prognosis and treatment, and other 'omics technologies such as metabolomics and proteomics. CONCLUSION: There are unique opportunities over the next decade to change the management of surgical disease radically, using these technologies. The directions that this may take are highlighted, including future advances such as the 100 000 Genomes Project