Global bifurcation of homoclinic trajectories of discrete dynamical systems

We prove the existence of an unbounded connected branch of nontrivial homoclinic trajectories of a family of discrete nonautonomous asymptotically hyperbolic systems parametrized by a circle under assumptions involving the topological properties of the asymptotic stable bundles.Comment: 28 pages. arXiv admin note: text overlap with arXiv:1111.140

RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis

A major cause of implant failure in skeletal tissues is failure of osseointegration, often due to lack of adhesion of cells to the titanium (Ti) alloy interface. Since arginine- glycine-aspartic acid (RGD)-containing peptides have been shown to regulate osteoblast adhesion, we tested the hypothesis that, bound to a Ti surface, these peptides would promote osteoblasts differentiation, while at the same time inhibit apoptosis. RGDS and RGES (control) peptides were covalently linked to Ti discs using an APTS linker. While the grafting of both RGDS and RGES significantly increased Ti surface roughness, contact angle analysis showed that APTS significantly increased the surface hydrophobicity; when the peptides were tethered to Ti, this was reduced. To evaluate attachment, MC3T3-E1 osteoblast cells were grown on these discs. Significantly more cells attached to the Ti-grafted RGDS then the Ti-grafted RGES control. Furthermore, expression of the osteoblasts phenotype was significantly enhanced on the Ti-grafted RGDS surface. When cells attached to the Ti-grafted RGDS were challenged with staurosporine, an apoptogen, there was significant inhibition of apoptosis; in contrast, osteoblasts adherent to the Ti-grafted RGES were killed. It is concluded that RGD-containing peptides covalently bonded to Ti promotes osteoblasts attachment and survival with minimal changes to the surface of the alloy. Therefore, such modifications to Ti would have the potential to promote osseointegration in vivo

Lacrimal defects in adult and senile rheumatoid arthritis.

IF: 0.56

Studies on analogues of succinic semialdehyde as substrates for succinate semialdehyde dehydrogenase from rat brain

The methyl ester of succinic semialdehyde (SSA) was examined as a substrate for succinate semialdehyde dehydrogenase (SSADH) from rat brain. It was found that the ester can be oxidized by the enzyme. Values of K(m) for SSA-Me were higher than for those for SSA, and for this substrate the enzyme showed a substrate- dependent inhibition. This finding suggests that the carboxylate group of SSA is not essential in the process of inhibition of SSADH by the substrate. Cyclopropyl analogues of SSA, cis- and trans-1-formyl-cyclopropan-2-carboxylic acids, were also individually tested as substrates of SSADH. Only the trans isomer was found to be oxidized to the corresponding dicarboxylic acid; it inhibited the enzyme in the same range of concentrations as SSA. The above data suggest that, as for \u3b3-aminobutyric acid, SSA is present in an unfolded, transoid conformation at the active site of SSADH

Gliomas of the optic nerve and chiasm. A clinical review

A series of 24 children with anterior optic gliomas, observed and for the most part operated upon in a neurosurgical service, is reviewed. A low incidence of unilateral nerve tumors and of associated neurofibromatosis, and a rather high frequency of precocious or pseudoprecocious puberty were noted in comparison with other series. Most tumors were low-grade growths. The results of surgical treatment reflect a good prognosis for unilateral tumors and an increasing prognostic ominousness for the posterior neoplastic development. Cerebrospinal fluid shunts and radiation treatment do have a role as adjuncts to surgical exploration and biopsy, which are generally indicated since no preoperative test seems to grant an absolute diagnosis. The opinion that chiasmal tumors should not be treated at all is not shared. When the treatment of an illness falls as far short of the ultimate, as does the therapy of neoplastic disease, then it is necessary to reconsider frequently the principles upon which it is based and the results it achieves. These results are two-fold, curative and palliative and, while our efforts are directed toward the former, we realize only too frequently that the best results will sometimes lie in palliation. The disappointment in accepting this lesser goal must not allow us to underestimate its importance or neglect the help it may give

Modelling of Hg Removal from Gaseous Streams and its Fixation in Hydroxyapatite-Based Adsorbents Modified with Copper Sulphide

In this work, a mathematical model of a fixed-bed process for elemental mercury removal from gaseous streams is proposed. Advective and diffusive processes were taken into account in the macroscopic mass balance along the bed, and diffusive process was considered in the microscopic mass balance inside the adsorbent particle in which the adsorption process occurs. In addition, a chemical reaction term was used to represent the mercury fixation by the adsorbent. The proposed model was implemented in the Environment for Modelling, Simulation and Optimization dynamic simulator. Model parameters were estimated based on experimental breakthrough curves, by minimizing the least-square function. The model satisfactorily described two experimental breakthrough curves of mercury removal using adsorbents with different preparation methods, both with high mercury fixation capacity. The proposed mathematical model was also able to consistently describe the mercury concentrations in the bed and in the particle

Anterior optic gliomas with precocious or pseudoprecocious puberty

5 patients with gliomas of the anterior optic pathways, histologically assessed or with strong diagnostic evidence, who developed precocious or pseudoprecocious puberty (2 cases) before the operation or after radiation treatment, are presented. Only 2 patients presented familial and/or personal evidence of neurofibromatosis. The production mechanism of these sexual changes is discussed

Progress report of the polycentric Usher Syndrome Study.

--

Differential features and gene mapping in Usher Syndrome Type 1 and 2

--