Search

The ligand N, N-bis(2-ethyl-4-methyl-imidazol-5-ylmethyl)-1-phenylethylamine (biaq) was prepared by Mannich reaction of 2-ethyl-4-methyl-1 H-imidazole, ( R)-1-phenylethylamine and formaldehyde. It was characterized by FTIR and NMR spectroscopy. This ligand reacts with CuCl2 to give a coordination compound with formula [Cu(biaq)Cl2]. In this compound, biaq acts as a tridentate ligand with one tertiary amine and two azole nitrogen atoms coordinated to the central metal atom. The complex was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction. The X-ray structure of [Cu(biaq)Cl2] shows a pentacoordinate cooper(II) atom, where two chloride ions and the three nitrogen atoms of the biaq ligand are coordinated in a distorted square pyramidal arrangement. The biological activity of the complex [Cu(biaq)Cl2] was tested using the Gram positive bacterium Bacillus subtilis as a model. Results revealed that the copper complex interfered with bacterial growth, inducing cell death, most probably by altering the primary structure of the chromosome, since a significant increase of the mutation frequency to rifampicin resistance was observed. [ABSTRACT FROM AUTHOR]

Aim Liver fibrosis results in a disproportion of the hepatic composition and architecture, characterized by a progressive accumulation of fibrillar proteins at the liver parenchyma. Modulated-differential scanning calorimetry (m DSC) is an experimental methodology able to determine the specific thermal signature from any biological substance, based on the variation in heat flow and heat capacity. As these physicochemical properties are directly influenced by compositional and structural changes, we decided to study the thermal behavior of the liver during fibrosis using m DSC. Methods Liver fibrosis was induced in rats by bile duct ligation or carbon tetrachloride administration. Degree of liver fibrosis was determined by histological examination using the Masson-trichrome stain, accompanied by hepatic expression of α-smooth muscle actin. The thermal analysis was performed in a modulated-differential scanning calorimeter using 20 mg of fresh liver mass. Results The liver showed a characteristic thermal signature in control animals, which progressively differed among mild ( F1), moderate ( F2) and advanced ( F3- F4) liver fibrosis. For heat flow, the hepatic thermal signature from F3- F4 rats exhibited significant differences when compared with F1, F2 and controls. In terms of heat capacity, liver specimens provided a specific thermal signature for each stage of disease, characterized by a transition temperature onset at 95°C for controls, whereas in F1, F2 and F3- F4 animals this temperature significantly decreased to 93°C, 84°C and 75°C, respectively. Conclusion Because the liver shows a differential thermal signature according to the degree of fibrosis, m DSC could be a novel tool in the study of liver fibrosis progression. [ABSTRACT FROM AUTHOR]

The ligand N, N-bis(2-ethyl-4-methyl-imidazol-5-ylmethyl)-1-phenylethylamine (biaq) was prepared by Mannich reaction of 2-ethyl-4-methyl-1 H-imidazole, ( R)-1-phenylethylamine and formaldehyde. It was characterized by FTIR and NMR spectroscopy. This ligand reacts with CuCl2 to give a coordination compound with formula [Cu(biaq)Cl2]. In this compound, biaq acts as a tridentate ligand with one tertiary amine and two azole nitrogen atoms coordinated to the central metal atom. The complex was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction. The X-ray structure of [Cu(biaq)Cl2] shows a pentacoordinate cooper(II) atom, where two chloride ions and the three nitrogen atoms of the biaq ligand are coordinated in a distorted square pyramidal arrangement. The biological activity of the complex [Cu(biaq)Cl2] was tested using the Gram positive bacterium Bacillus subtilis as a model. Results revealed that the copper complex interfered with bacterial growth, inducing cell death, most probably by altering the primary structure of the chromosome, since a significant increase of the mutation frequency to rifampicin resistance was observed. [ABSTRACT FROM AUTHOR]

Background It is unknown whether male black-handed spider monkeys ( Ateles geoffroyi) undergo a reproductive decline as they age. The purpose of this work was investigating whether serum testosterone and semen quality decrease with age in these primates as occur in other species. Methods In this study, we assessed age variations in the concentration of serum testosterone, sperm counts, and motility in nine males. We took serum blood samples and semen samples by electroejaculation of anesthetized males throughout the fertile season. Results We found that testosterone levels and total sperm concentration, motile, progressive, fast linearly moving, medium linearly moving, slow linearly moving and immotile sperm significantly decreased with age. Conclusions Our results show that a reproductive decline occurs in male spider monkeys because of a decrease in sperm counts. These results are similar to those of rhesus monkeys and men, despite the phylogenetic distance between New and Old World primates. [ABSTRACT FROM AUTHOR]

Summary The Salar Grande in the Coastal Range of Northern Chile is a fossil evaporitic basin filled with almost pure halite (95% NaCl average). It is assumed that the basin has not received input of brines since the Pliocene (5.3 to 1.8 million years). Below 1 m the halite has remained undissolved since this time, whereas the upper layer has been dissolved and recrystallized by dripping fogs and occasional rainfall. We compared the archaeal community at different depths using both nested PCR and cultivation. The upper 10 cm of halite crust contained diverse haloarchaeal species, including several from new genera, but their provenance is unknown. For samples deeper in the core, a new and rigorous procedure for chemically sterilizing the surface of single halite crystals was developed. These halite crystals contained only species of the genus Halobacterium ( Hbt.). Halobacterium salinarum-like sequences were detected by PCR, and evidence that they were from ancient DNA include: comparison with numerous negative controls; detection of 16S rRNA sequence differences in non-conserved regions, indicating genuine evolutionary mutations rather than PCR-cloning artefacts; independent isolation of Hbt. salinarum from ancient halite; and diverse mechanisms possessed by this species for minimizing radiation damage and thus enhancing its potential for long-term survival. Haloarchaea related to Hbt. noricense were obtained from enrichment cultures from ∼0.4 and 15.4 m depth. We investigated Hbt. noricense strain A1 and found that when trapped inside halite crystals its recovery was as rapid after 27 months of entombment as at day 0, faring much better than other extreme halophiles. A biogeographical investigation showed that Hbt. noricense-like organisms were: commonly found in surface-sterilized ancient halite, associated with salt mines, in halite crusts, and, despite a much more intense search, only rarely detected in surface environments. We conclude that some Halobacterium species are specialists at long-term survival in halite. [ABSTRACT FROM AUTHOR]

Background and Aim: Development of hepatic fibrosis is a complex process that involves oxidative stress (OS) and an altered balance between pro- and anti-apoptotic molecules. Since Bcl-2 overexpression preserves viability against OS, our objective was to address the effect of Bcl-2 overexpression in the hepatic stellate cells (HSC) cell-line CFSC-2G under acetaldehyde and H2O2 challenge, and explore if it protects these cells against OS, induces replicative senescence and/or modify extracellular matrix (ECM) remodeling potential. Methods: To induce Bcl-2 overexpression, HSC cell line CFSC-2G was transfected by lipofection technique. Green fluorescent protein-only CFSC-2G cells were used as a control. Cell survival after H2O2 treatment and total protein oxidation were assessed. To determine cell cycle arrest, proliferation-rate, DNA synthesis and senescence were assessed. Matrix metalloproteinases (MMP), tissue-inhibitor of MMP (TIMP), transglutaminases (TG) and smooth muscle a-actin (α-SMA) were evaluated by western blot in response to acetaldehyde treatment as markers of ECM remodeling capacity in addition to transforming growth factor-β (TGF-β) mRNA. Results: Cells overexpressing Bcl-2 survived ≈ 20% more than control cells when exposed to H2O2 and ≈ 35% proteins were protected from oxidation, but Bcl-2 did not slow proliferation or induced senescence. Bcl-2 overexpression did not change α-SMA levels, but it increased TIMP-1 (55%), tissue transglutaminases (tTG) (25%) and TGF-β mRNA (49%), when exposed to acetaldehyde, while MMP-13 content decreased (47%). Conclusions: Bcl-2 overexpression protected HSC against oxidative stress but it did not induce replicative senescence. It increased TIMP-1, tTG and TGF-β mRNA levels and decreased MMP-13 content, suggesting that Bcl-2 overexpression may play a key role in the progression of fibrosis in chronic liver diseases. [ABSTRACT FROM AUTHOR]

Purpose The diagnosis of pancreatic cancer (PC) is most frequently established in advanced stages. The aim of this study is to estimate the likelihood ratios (LRs) of diagnostic data with regards to PC that could be used to approach an earlier diagnosis. Methods A case–control study of 300 patients – 150 histological diagnosed cases of PC and 150 age-matched controls hospitalized for study of jaundice, abdominal pain, weight loss and/or chronic pancreatitis – was conducted. Bayesian probabilities in the form of LRs were estimated for PC predictions. Results Probability of PC was associated with jaundice [odds ratio (OR) 2.89; confidence interval (CI) 1.71–4.85], glycemic disturbance (OR 5.64; CI 2.36–13.46), tobacco index >20 (OR 2.11; CI 1.08–4.09) and tumour marker CA 19-9 (OR 9.33; CI 1.36–63.95). Computed tomography showed the highest test performance with regards to PC when comparing with other diagnostic tests. LRs for variables relevant to PC were estimated, among the most relevant: jaundice LR + 1.92, CA 19-9 LR + 5.36 and computed tomography LR + 4.15. The prediction model with an endoscopic retrograde cholangiopancreatography at a tertiary referral hospital determined a 67% probability of detecting PC. Conclusions Through a Bayesian approach we can combine clinical, laboratory and imaging data to approximate to an earlier diagnosis of PC. [ABSTRACT FROM AUTHOR]

Although pancreatic necrosis classifies acute pancreatitis (AP) as severe, many patients with tomographic evidence of necrosis never develop systemic complications. Our aim was to analyze the incidence of pancreatic necrosis, organ failure (OF), and the relationship between them. Medical records from 165 patients with a first AP episode and in whom a contrast-enhanced computed tomography (CECT) was performed were analyzed. Pancreatic necrosis was diagnosed as non-enhancing areas of the pancreas on the CECT and was graded as <30%, 30%–50%, and >50%. Pancreatic infection was assessed by guided percutaneous aspiration. Organ failure was defined according to the Atlanta criteria. Of 165 patients (mean age 42 years, 85 men), 54 (33%) had pancreatic necrosis. Necrosis was graded as <30% in 25 subjects (46%), 30%–50% in 16 (30%), and >50% in 13 (24%). Pancreatic infection was diagnosed in 14 cases (26%). Organ failure occurred in 49 patients: in 20 patients (37%) with necrosis, and in 29 patients (26%) without necrosis ( P = 0.20). Extensive pancreatic necrosis (>50%) ( P < 0.05) and infected necrosis ( P < 0.05) were significantly associated with OF. Eight patients, all of them with OF, died. In 6 of these cases infected pancreatic necrosis was present. Patients with pancreatic necrosis are not necessarily at risk of developing OF. However, it should be considered an important risk factor when the necrotizing process compromises more than 50% of the gland and is infected. [ABSTRACT FROM AUTHOR]

In this work, a novel, displacement‐driven approach to crystal plasticity based on embedded strong discontinuities (ESDA) is presented, cf. [1, 2]. In contrast to the classical strain‐driven approach, which connects the Schmid stress to the slip strain at a certain slip system, the novel approach applies a traction‐separation law to connect the Schmid stresses to the slip displacements. Surprisingly, both models show similar mathematical structures, which allows to develop a unifying algorithmic formulation. The elaborated algorithmic formulation is fully implicit and the inequalities characterizing rate‐independent crystal plasticity theory are solved efficiently by means of so‐called Fischer‐Burmeister NCP functions, cf. [3]. The resulting solution scheme is extremely robust – even for an arbitrary number of simultaneously active slip systems. [ABSTRACT FROM AUTHOR]

In the cationic complex present in the title compound, chloro[2-(4-imidazolyl-κN¹)ethylamine-κN] (1,10-phenanthroline-κ²N,N')copper(II) chloride monohydrate, [CuCl(C5H9N3)(C12H8N2)]Cl·H2O, the metal centre adopts a five coordinate geometry, ligated by the two phenanthroline N atoms, two amine N atoms of the histamine ligand (one aliphatic and one from the imidazole ring) and a chloro ligand. The geometry around the Cu atom is a distorted compressed trigonal bipyramid, with one phenanthroline N and one imidazole N atom in the axial positions, and the other phenanthroline N atom, the histamine amine N atom and the chloro ligand in the equatorial positions. The structure includes an uncoordinated water molecule, and a Cl- ion to complete the charge. The water molecule is hydrogen bonded to both Cl- ions (coordinated and uncoordinated), and exhibits a close Cu···H contact in the equatorial plane of the bipyramid. [ABSTRACT FROM AUTHOR]

This paper deals with the modeling of fiber-reinforced PMMA. Focus is on the macroscopic mechanical response with emphasis on the fracture properties such as the ultimate strength and the fracture energy. In order to capture the macroscopic mechanical response of PMMA, a finite element formulation is presented. While the elastic response of the fibres and that of the surrounding matrix are modelled in standard manner, i.e., by standard bulk material models, the relevant failure modes such as cracking of the fibres are accounted for by means of the so-called Strong Discontinuity Approach (SDA). Since the fibres are relatively small, their fracture mechanical properties crucially depend on their geometry, i.e., they show a pronounced size effect. Based on numerical analyses of fibres with different geometries, the aforementioned size effect is naturally incorporated into the formulation [1]. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The title compound, [PdCl(C14H23N5)]Cl·2H2O, contains a four-coordinate palladium complex, in which the planes of the pyrazole rings are almost perpendicular. This is mainly a consequence of the close steric contacts between the methyl groups which would occur in the case of mirror symmetry, which are avoided by adopting a quasi-twofold rotation symmetry. [ABSTRACT FROM AUTHOR]