Integral equations for the H- X- and Y-functions

We come back to a non linear integral equation satisfied by the function H, which is distinct from the classical H-equation. Established for the first time by Busbridge (1955), it appeared occasionally in the literature since then. First of all, this equation is generalized over the whole complex plane using the method of residues. Then its counterpart in a finite slab is derived; it consists in two series of integral equations for the X- and Y-functions. These integral equations are finally applied to the solution of the albedo problem in a slab.Comment: 20 pages, JQSRT, accepted 9 July 200

Transcriptional activation by the mouse oestrogen receptor

The oestrogen receptor is a ligand inducible transcription factor that belongs to a family of nuclear receptor proteins. Previous studies have shown that in transient transfection experiments two regions of the oestrogen receptor protein are capable of stimulating transcription. One, located N-terminal to the DNA binding domain called transcriptional activation function 1, TAF-1, can stimulate transcription constitutively whilst TAF-2, located in the C-terminal hormone binding domain requires oestrogen binding for its activity. Analysis of mutant mouse oestrogen receptors has identified a region of the hormone binding domain important for TAF-2. The amino acid sequence in this region is conserved in other members of the nuclear receptor family. Point mutation of conserved hydrophobic residues practically abolished hormone dependent transcriptional stimulation by TAF-2 without affecting oestradiol or DNA binding. The ability of TAF-2 and TAF-1 to cooperate in stimulating transcription in the full-length receptor was also abolished by mutation of the conserved hydrophobic residues but not conserved acidic residues. Mutagenesis of the corresponding residues in the glucocorticoid receptor showed similar results indicating that these residues may be important for ligand inducible transcription by other members of the nuclear receptor family. A yeast genetic screen was established to identify target(s) for TAF-2 that were important for its ability to stimulate transcription. No candidate targets were identified but analysis of the TAF-2 defective mutants suggested that the mechanism whereby TAF-2 stimulates transcription in mammalian cells is not conserved in yeast. Finally the effects of mutations in the steroid binding domain upon transcriptional activation by the oestrogen receptor have been examined. One finding of these studies was that some mutations, that abolished oestradiol binding and transcriptional activation, did not affect transcriptional activation induced by another ligand indicating that while the binding sites for different ligands overlap they are distinct

Exact solution of the standard transfer problem in a stellar atmosphere

We come back to the analytical solution of the standard transfer problem in a stellar atmosphere. It consists in solving the radiative transfer equation in a homogeneous and isothermal plane-parallel atmosphere, with light scattering taken as isotropic and monochromatic. The literature on the subject is reviewed and the existing solution in a finite slab is improved thanks to the introduction of non classical auxiliary functions. Eleven-figure tables of the solution are given for typical values of the input parameters currently met in stellar atmospheres.Comment: 23 pages, 1 figur

Development and piloting of a food-based intervention to increase vitamin E intake in pregnant women in a randomised controlled trial

Acknowledgement This study was funded by the University of Aberdeen and an unrestricted grant from Baxters Food Group Ltd. LC acknowledges funding from the RESAS programme of the Scottish Government.Peer reviewedPublisher PD

Loss of pRB and p107 disrupts cartilage development and promotes enchondroma formation

The pocket proteins pRB, p107 and p130 have established roles in regulating the cell cycle through the control of E2F activity. The pocket proteins regulate differentiation of a number of tissues in both cell cycle-dependent and -independent manners. Prior studies showed that mutation of p107 and p130 in the mouse leads to defects in cartilage development during endochondral ossification, the process by which long bones form. Despite evidence of a role for pRB in osteoblast differentiation, it is unknown whether it functions during cartilage development. Here, we show that mutation of Rb in the early mesenchyme of p107-mutant mice results in severe cartilage defects in the growth plates of long bones. This is attributable to inappropriate chondrocyte proliferation that persists after birth and leads to the formation of enchondromas in the growth plates as early as 8 weeks of age. Genetic crosses show that development of these tumorigenic lesions is E2f3 dependent. These results reveal an overlapping role for pRB and p107 in cartilage development, endochondral ossification and enchondroma formation that reflects their coordination of cell-cycle exit at appropriate developmental stages.Virginia and D.K. Ludwig Fund for Cancer Research (Fellowship)National Cancer Institute (U.S.) (Grant CA121921

Approach to The Assessment System Stability Through Modelling of Organizational Structure of The Object

Relevance of the topic due to the use of structural modeling guidelines for describing and studying the behavior of economic entities with a view to deciding on the best choice of a state in which an object may be economic in terms of stability, functionality, profitability and system compatibility between economic entities

E2f4 and E2f5 are essential for the development of the male reproductive system

The E2F transcription factors are primarily implicated in the regulation of entry and exit from the cell cycle. However, in vivo studies have established additional roles for E2Fs during organ development and homeostasis. With the goal of addressing the intestinal requirements of E2f4 and E2f5, we crossed mice carrying Vil-cre, E2f4 conditional and E2f5 germline alleles. E2f4 deletion had no detectable effect on intestinal development. However, E2f4f/f;E2f5+/−;Vil-cre males, but not E2f4f/f;Vil-cre littermates, were unexpectedly sterile. This defect was not due to defective spermatogenesis. Instead, the seminiferous tubules and rete testes showed significant dilation, and spermatozoa accumulated aberrantly in the rete testis and efferent ducts. Our data show that these problems result from defective efferent ducts, a tissue whose primary function is to concentrate sperm through fluid absorption. First, Vil-cre expression, and consequent E2F4 loss, was specific to the efferent ducts and not other reproductive tract tissues. Second, the E2f4f/f;E2f5+/−;Vil-cre efferent ducts had completely lost multiciliated cells and greatly reduced levels of critical absorptive cell proteins: aquaporin1, a water channel protein, and clusterin, an endocytic marker. Collectively, the observed testis phenotypes suggest a fluid flux defect. Remarkably, we observed rete testis dilation prior to the normal time of seminiferous fluid production, arguing that the efferent duct defects promote excessive secretory activity within the reproductive tract. Finally, we also detect key aspects of these testis defects in E2f5−/− mice. Thus, we conclude that E2f4 and E2f5 display overlapping roles in controlling the normal development of the male reproductive system.National Institutes of Health (U.S.) (Grant NIH-P01 CA42063

Culture of airway epithelial cells from neonates sampled within 48-hours of birth

Peer reviewedPublisher PD

The aspects of gender diversity in management boards

In this work, it is shown that gender diversity is important not only for ethical issues but for the better financial performance of companies. The study showed a positive effect of the percentage of women on the board of directors on brand value in the tech industry. Furthermore, there is proof that quality (diversity) on the board is better than quantity (number of members)