Structural transformations in poly(di-n-alkylsiloxane)s with alkyl side groups containing 7 to 10 carbon atoms

Temperature dependent X-ray diffraction studies of poly(di-n-alkylsiloxane)s substituted with side chains containing 7 to 10 carbon atoms have been carried out in order to elucidate the crystalline structure of these materials. In contrast to their lower substituted homologues, no evidence for the presence of a hexagonal columnar mesophase could be found for the investigated materials. At low temperatures, far below the melting temperature, the polysiloxane backbones are assumed to pack in an orthorhombic lattice, with the n-alkyl side chains in a planar all-trans conformation and oriented perpendicularly to the backbone. The paraffinic n-alkyl side chains were found to crystallize in an orthorhombic lattice. The thermal behaviour of the investigated materials has been observed to show an odd-even effect. Whereas poly(di-n-heptylsiloxane) and poly(di-n-nonylsiloxane) were found to melt in a single step, an intermediate state of order was observed for poly(di-n-octylsiloxane) and poly(di-n-decylsiloxane) upon heating from the crystalline to the isotropic state. For this intermediate state, a pseudohexagonal packing of the n-alkyl side chains is proposed

Hydrosilylation of 1-alkenes with dichlorosilane

Symmetrically and unsymmetrically substituted diorganodichlorosilanes have been prepared by hydrosilylation with dichlorosilane using two different platinum catalysts, i.e., hexachloroplatinic acid (Speier's catalyst) and a platinum cyclovinylmethylsiloxane complex. Hydrosilylation of unsubstituted 1-alkenes proved to be very efficient, yielding anti-Markonikov substituted di-n-alkyldichlorosilanes. However, no reaction was observed when electron-deficient 1-alkenes were used. Octacarbonyldicobalt enabled formation of the monoadduct of 1H,1H,2H-perfluoro-1-hexene with dichlorosilane, which was employed in a second hydrosilylation of the olefin. Thus, the anti-Markovnikov diadduct was obtained in 40% overall yield. The two-step synthesis has also been applied successfully to obtain unsymmetrically substituted diorganodichlorosilanes containing nitrile and ether groups

De electieve inleiding van de baring : een prospectief obstetrisch en psychologisch onderzoek

In een terugblik op de beide onderzoeken wordt kort ingegaan op enkele opvallende verschillen in gevonden effecten tussen het obstetrische en het psychologische onderzoek. Vervolgens wordt op basis van de beide onderzoeken een antwoord gegeven op de vraag in hoeverre electief inleiden van de baring wenselijk is of niet. Besloten wordt met enige aanbevelingen omtrent de toepassing van de electieve inleiding in de obstetrische praktijk. Zowel in het obstetrische als in het psychologische onderzoek komt het voor, dat in het ene onderzoek een significant verschil in effect is gevonden tussen vrouwen die hun baring eJectief hebben laten inleiden en vrouwen met een spontaan begonnen baring, terwijl dit verschil niet is gevonden in het andere onderzoek. In het psychologische onderzoek wordt na een spontaan begonnen bevalling vaker borstvoeding gegeven dan na een electieve inleiding, in het obstetrische onderzoek niet. In het obstetrische onderzoek vinden bij de electief ingeleide groep meer kunstverlossingen plaats, in het psychologische onderzoek is geen verschil gevonden. Deze verschillen tussen de beide onderzoeken berusten vermoedelijk op verschillen in de samenstelling van de onderzochte groepen, waarover in de gezamenlijke inleiding bij dit proefschrift is gesproken. Bij de bespreking van de borstvoeding in het psychologische onderzoek is de aannemelijkheid van deze verklaring al gebleken. In het psychologische onderzoek zijn immers meer strikte criteria gehanteerd bij de toepassing van het begrip "electief' dan in het obstetrische onderzoek. Dat zulke verschillen optreden in twee onderzoeken met grotendeels dezelfde onderzochte personen toont aan, dat betrekkelijk geringe verschuivingen in de criteria voor selectie van onderzoekspersonen belangrijke gevolgen kunnen hebben en dat grote zorgvuldigheid is geboden bij de beschrijving van deze criteria

Quality of life in patients with resected oesophageal cancer

__Abstract__ Quality of Life (QL) is hard to assess and seldom measured in patients having carcinomas with an unfavourable prognosis. Oesphageal cancer is one of the malignancies with a low 5-year survival rate. Dysphagia (problems in swallowing food) is considered to be the most important indicator of QL in patients with oesophageal carcinoma. Moreover, the psycho-social aspects and subjective QL in cancer have recently gained importance. The present study investigated QL in a 132 patients with oesophageal cancer. Eighty-three of them had a surgical operation (removal of part of the oesophagus and part of the stomach, followed by a reconstruction of the digestive tract). Sixty-seven patients filled in questionnaires before and after the operation. Complete sets of data were obtained from 62 patients. Time interval between operation and postoperative assessment varied from 3 to 7 months. Indicators of QL were: Psychological Distress, Physical Symptoms, Global Evaluations, Activity Level, Swallowing Problems and Food Intake. Swallowing Problems showed moderate correlations with the other QL indicators. Physical Symptoms increased, whereas the Activity Level, Psychological Distress, and Swallowing Problems decreased; Global Evaluations remained unaltered

Serum and cutaneous transcriptional expression levels of IL31 are minimal in cutaneous T cell lymphoma variants

AbstractAimRecent studies suggested a role for IL31 in the pathogenesis of pruritus and disease severity in patients with cutaneous T cell lymphomas (CTCL). However, discrepant results were reported for IL31 serum levels, transcriptional expression levels or immunohistochemistry studies and its relation to pruritus intensity and/or disease severity in CTCL. Most studies did not distinguish between different CTCL variants. We investigated IL31 serum levels in different subtypes of CTCL, including Mycosis Fungoides (MF) (typically not pruritic), Folliculotropic Mycosis Fungoides (FMF) and Sézary syndrome (SS) (both often pruritic).MethodsFrom 54 CTCL patients (17 SS, 21 FMF and 16 classic MF) serum samples were analyzed with a high sensitivity V-PLEX immunoassay for IL31. The study group included 35/54 (65%) patients with complaints of pruritus. Thirty-five patients had advanced stage disease (≥ stage IIB). A visual analog scale score (VAS score) for pruritus was available in 29 CTCL patients (7 SS, 9 FMF and 13 classic MF) and in other cases complaints of pruritus were retrieved medical records. qPCR analyses for IL31 expression were performed in lesional skin biopsies from 8 CTCL patients. Serum samples from 4 healthy individuals without pruritus and from 5 atopic dermatitis (AD) patients with severe pruritus were included as controls.ResultsIn 11/54 (20%) of CTCL patients low serum levels of IL31 were detected (mean 0.48pg/mL, range 0.20-1.39pg/mL) including 6/17 (35%) SS patients (mean 0.57pg/mL) and 5/21 (24%) FMF patients (mean 0.33 pg/mL). All 11 patients with detectable levels of IL31 reported complaints of moderate to severe pruritus and 9/11 patients presented with advanced stage disease (≥IIB). qPCR analyses resulted in lowly expressed IL31 expression levels in 4 of 8 patients; these patients all suffered from pruritus and advanced stage disease.ConclusionsTranslational and transcriptional expression levels of IL31 were very low or undetectable in CTCL patients. Detectable low IL31 serum levels were exclusively observed in SS and FMF patients and not in patients with classic MF. However, these marginal IL31 levels in a small proportion of CTCL patients do not support an essential role for IL31  in CTCL patients.Dermatology-oncolog

GNAQ and GNA11 mutations and downstream YAP activation in choroidal nevi

Dermatology-oncolog

GNAQ and GNA11 mutations and downstream YAP activation in choroidal nevi

Background: Mutations in GNAQ/11 genes are considered an early event in the development of uveal melanoma that may derive from a pre-existing nevus. The Hippo pathway, by way of YAP activation, rather than MAP kinase, has a role in the oncogenic capacity of GNAQ/11 mutations.Methods: We investigated 16 nevi from 13 human eyes for driver GNAQ/11 mutations using droplet digital PCR and determined whether nevi are clonal by quantifying mutant nevus cell fractions. Immunohistochemistry was performed on 15 nevi to analyse YAP activation.Results: For 15 out of 16 nevi, a GNAQ/11 mutation was detected in the nevus cells albeit at a low frequency with a median of 13%. Nuclear YAP, a transcriptional co-activator in the Hippo tumour-suppressor pathway, was detected in 14/15 nevi.Conclusions: Our analysis suggests that a mutation in GNAQ/11 occurs in a subset of choroidal nevus cells. We hypothesise that GNAQ/11 mutant-driven extracellular mitogenic signalling involving YAP activation leads to accumulation of wild-type nevus cells

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

La producció catalana de fonts d'informació electrònica sobre dret: estat de la qüestió

L'article identifica i descriu les fonts d'informació electrònica sobre dret produïdes a Catalunya, i les produïdes fora del nostre país, que, en la major part del seu contingut, fan referència al dret de Catalunya. Es tracten les fonts d'informació d'interés per a la globalitat del dret ¿publicacions de documents parlamentaris, repertoris de legislació i jurisprudència, publicacions doctrinals i obres de referència¿ i per a cada una de les seves branques o especialitats, així com una sèrie de nous recursos desenvolupats a la xarxa Internet i d'interés per al dret

Structural correlation between the columnar mesophase and the melt in poly(di-n-alkylsiloxane)s

Phase transitions of poly(dialkylsiloxane)s substituted with propyl and butyl groups are reported based on X-ray diffractometry. The structure in the mesophase and in the melt of polymers with 2 to 10 carbon atoms in each side chain is compared. Both phases display a linear dependence of the molecular cross-section on the length of the alkyl group demonstrating their structural similarity. By means of differential scanning calorimetry it is shown that the temperature range of the mesophase remains practically unchanged in width as well as in absolute temperature for dibutyl up to dihexyl substituted polysiloxanes