Search results for "polymorph"
showing 10 items of 2115 documents
Residual vein thrombosis and onset of post-thrombotic syndrome: Influence of the 4G/5G polymorphism of plasminogen activator inhibitor-1 gene
2013
Abstract Background Plasminogen activator inhibitor-1 (PAI-1) is the most important inhibitor of plasminogen activator. The functional 4G/5G polymorphism of the gene coding for PAI-1 may affect PAI-1 plasmatic activity, influencing the imbalance between coagulation and fibrinolysis cascades. In this prospective cohort analytic study, we investigated the role of this single nucleotide polymorphism in the persistence of thrombotic lesion and the occurrence of post-thrombotic syndrome. Patients/Methods In a group of 168 patients with post-surgical deep vein thrombosis of the legs, we analyzed the 4G/5G polymorphism in the promoter of PAI-1 gene and plasmatic PAI-1 activity. Enrolled patients w…
Age-Related Inflammatory Diseases: Role of Genetics and Gender in the Pathophysiology of Alzheimer's Disease
2007
Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western societies mainly accounts for clinical dementia. A high proportion of women are affected by this disease, especially at a very advanced age, which might to a large extent be associated with the fact that women live longer. However, some studies suggest that incidence rates may be really increased in women. For this reason the influence of estrogens on the brain and the decrease of it during menopause are of special interest. After menopause, circulating levels of estrogens markedly decline, influencing several brain processes predicted to influence AD risk. The control of estrogens on oxid…
Association Mapping Based on a Common-Garden Migration Experiment Reveals Candidate Genes for Migration Tendency in Brown Trout
2019
A better understanding of the environmental and genetic contribution to migratory behavior and the evolution of traits linked to migration is crucial for fish conservation and fisheries management. Up to date, a few genes with unequivocal influence on the adoption of alternative migration strategies have been identified in salmonids. Here, we used a common garden set-up to measure individual migration distances of generally highly polymorphic brown trout Salmo trutta from two populations. Fish from the assumedly resident population showed clearly shorter migration distances than the fish from the assumed migratory population at the ages of 2 and 3 years. By using two alternative analytical …
Genetic colour variation visible for predators and conspecifics is concealed from humans in a polymorphic moth
2022
The definition of colour polymorphism is intuitive: genetic variants express discretely coloured phenotypes. This classification is, however, elusive as humans form subjective categories or ignore differences that cannot be seen by human eyes. We demonstrate an example of a 'cryptic morph' in a polymorphic wood tiger moth (Arctia plantaginis), a phenomenon that may be common among well-studied species. We used pedigree data from nearly 20,000 individuals to infer the inheritance of hindwing colouration. The evidence supports a single Mendelian locus with two alleles in males: WW and Wy produce the white and yy the yellow hindwing colour. The inheritance could not be resolved in females as t…
The formation of silica high temperature polymorphs from quartz: Influence of grain size and mineralising agents
2015
Abstract The formation of high-temperature silica polymorphs in presence of Na and K has been studied at various temperatures and soaking times, starting from quartzes of different grain size, ex situ as well as in situ. The results show that cristobalite and tridymite formation is strongly influenced by the nature and the amount of mineraliser added. In particular, K seems to discriminate more between the two structures, as it produces the largest observed amount of cristobalite. The disappearance of quartz can be controlled by the proper combination of mineraliser/temperature/time, which in turn control the amount and the type of polymorph formed, together with the amount of amorphous mat…
Hexamorphism of Dantrolene: Insight into the Crystal Structures, Stability, and Phase Transformations
2021
Dantrolene represents yet another interesting example of abundant molecular crystal polymorphism existing in at least six different neat polymorphs, three of which can be obtained via crystallizati...
Polyamorphic transformation induced by electron irradiation ina-SiO2glass
2009
We report a study by electron paramagnetic resonance of amorphous silicon dioxide $(a{\text{-SiO}}_{2})$ irradiated by 2.5 MeV electrons in the dose range from $1.2\ifmmode\times\else\texttimes\fi{}{10}^{3}$ to $5\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{kGy}$. By measuring the change in the splitting of the primary $^{29}\text{S}\text{i}$ hyperfine doublet of the ${E}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ centers we evidenced an irradiation induced local (around the defects) densification of $a{\text{-SiO}}_{2}$. Our data show that the local degree of densification of the materials is significantly higher than that obtained by mean density measurements, suggesting that the …
X-ray Powder Structure Determination and Thermal Behavior of a New Modification of Pb(II) Selenite
2002
The crystal structure of a new polymorphic form of lead(II) selenite (PbSeO3) was solved directly from conventional X-ray powder diffraction data. Direct methods and Rietveld refinement techniques were used for the structure determination. The compound crystallizes in the monoclinic space group P21/c (no. 14) with cell dimensions a = 9.1587(1) A, b = 8.0902(1) A, c = 8.7932(1) A, β = 103.032(1)°, and V = 634.76(2) A3. The final refinement gave background excluded Rp = 6.22%, Rwp = 8.81%, and RB = 2.16% by using 45 structural and 15 profile parameters with 10 atoms in an asymmetric unit. The three-dimensional structure consists of 9-coordinated lead atoms, which are linked by three bidentate…
Polymorphism in phase-change materials: melt-quenched and as-deposited amorphous structures in Ge2Sb2Te5from density functional calculations
2011
The as-deposited (AD) amorphous structure of the prototype phase change material Ge${}_{2}$Sb${}_{2}$Te${}_{5}$ (GST-225) has been studied by density functional calculations for a 648-atom sample generated by computer-aided deposition at 300 K. The AD sample differs from a melt-quenched (MQ) sample in essential ways: (1) Ge atoms are predominantly tetrahedrally coordinated, and (2) homopolar and Ge-Sb bonds are more common and reduce the number of $\mathit{ABAB}$ squares ($A=\mathrm{Ge}$, Sb; $B=\mathrm{Te}$), the characteristic building blocks of the material. The first observation resolves the contradiction between measured (EXAFS) and calculated Ge-Te bond lengths, and the latter explain…
Confinement-induced polymorphism in acetylsalicylic acid–nanoporous glass composites
2018
We report on the experimental observation of confinement-induced new phase appearance in acetylsalicylic acid (ASA)–porous glass (PG) composites. In this study, ASA was embedded in PG host matrices of various pore widths (15–200 nm). The Raman spectra and positron annihilation lifetime measurements exhibit the existence of ASA nanocrystals in the PG matrix. The DSC data revealed that the melting temperature TM and excess specific heat decrease with decreasing the size of embedded ASA nanocrystals. The close inspection of the TM dependence versus diameter of filled pores has shown that the ASA crystallizes in polymorph II in confined matrix. Moreover, it was demonstrated that the ASA spatial…