190 research outputs found

    Roman oil lamps with peltae relief on base. New evidence from Apsaros (Gonio, Georgia)

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    Discovery of two lamps at the Roman fort of Apsaros (Gonio, Georgia) offers further insights concerning adaptation of the pelta motif on Roman lamps. Inquiry into the nature of the ornaments on the base – previously unknown in Colchis – leads to conclusions about the possible influx of goods to the fort located on the outskirts of the Roman Empire.Discovery of two lamps at the Roman fort of Apsaros (Gonio, Georgia) offers further insights concerning adaptation of the pelta motif on Roman lamps. Inquiry into the nature of the ornaments on the base – previously unknown in Colchis – leads to conclusions about the possible influx of goods to the fort located on the outskirts of the Roman Empire

    Analysis of calcium homeostasis in fresh lymphocytes from patients with sporadic Alzheimer's disease or mild cognitive impairment

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    AbstractAlzheimer's disease (AD) is the most widespread, age-related neurodegenerative disorder. Its two subtypes are sporadic AD (SAD) of unknown etiology and genetically encoded familial AD (FAD). The onset of AD is often preceded by mild cognitive impairment (MCI). Calcium dynamics were found to be dysregulated in FAD models, but little is known about the features of calcium dynamics in SAD. To explore calcium homeostasis during the early stages of SAD, we investigated store-operated calcium entry (SOCE) and inositol triphosphate receptor (IP3R)-mediated calcium release into the cytoplasm in unmodified B lymphocytes from MCI and SAD patients and compared them with non-demented subjects (NDS). Calcium levels in the endoplasmic reticulum and both the rising and falling SOCE slopes were very similar in all three groups. However, we found that SAD and MCI cells were more prone to IP3R activation than NDS cells, and increases in calcium levels in the cytoplasm were almost twice as frequent in SAD cells than in NDS cells. MCI cells and SAD cells exhibited an enhanced magnitude of calcium influx during SOCE. MCI cells but not SAD cells were characterized by higher basal cellular calcium levels than NDS cells. In summary, perturbed calcium homeostasis was observed in peripheral cells from MCI and SAD patients. Thus, lymphocytes obtained from MCI subjects may be promising in the early diagnosis of individuals who will eventually develop SAD. However, no conclusions are made regarding SAD due to the limited number patients. This article is part of a Special Issue entitled: 12th European Symposium on Calcium

    Theoretical study of cobalt and nickel complexes involved in methyl transfer reactions: structures, redox potentials and methyl binding energies

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    Cobalamins, cobalt glyoximate complexes and nickel complexes with Triphos (bis(diphenylphosphinoethyl)phenylphosphine) and PPh2CH2CH2SEt ligands were studied with the DFT/BP86 method in connection with methyl transfer reactions. Geometries, methyl binding energies and redox potentials were determined for the studied complexes. Three- and four-coordinate structures were considered for nickel complex with PPh2CH2CH2SEt ligand, whereas four- and five-coordinate for its methyl derivative. On the basis of calculations, the possible mechanism of methyl transfer reaction between cobalt and nickel complexes was considered

    Theoretical Studies of Acetyl-CoA Synthase Catalytic Mechanism

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    DFT calculations were performed for the A-cluster from the enzyme Acetyl-CoA synthase (ACS). The acid constants (pKa), reduction potentials, and pH-dependent reduction potential for the A-cluster with different oxidation states and ligands were calculated. Good agreement of the reduction potentials, dependent on pH in the experiment, was obtained. On the basis of the calculations, a mechanism for the methylation reaction involving two–electron reduction and protonation on the proximal nickel atom of the reduced A-cluster is proposed

    Pericardium: structure and function in health and disease

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    Normal pericardium consists of an outer sac called fibrous pericardium and an inner one called serous pericardium. The two layers of serous pericardium: visceral and parietal are separated by the pericardial cavity, which contains 20 to 60 mL of the plasma ultrafiltrate. The pericardium acts as mechanical protection for the heart and big vessels, and a lubrication to reduce friction between the heart and the surrounding structures. A very important role in all aspects of pericardial functions is played by mesothelial cells. The mesothelial cells form a monolayer lining the serosal cavity and play an important role in antigen presentation, inflammation and tissue repair, coagulation and fibrinolysis. The two major types of mesothelial cells, flat or cuboid, differ substantially in their ultrastructure and, probably, functions. The latter display abundant microvilli, RER, Golgi dense bodies, membrane-bound vesicles and intracellular vacuoles containing electron-dense material described as dense bodies. The normal structure and functions of the pericardium determine correct healing after its injury as a result of surgery or microbial infection. The unfavorable resolution of acute or chronic pericarditis leads to the formation of adhesions between pericardial leaflets which may lead to serious complications

    TD-DFT insight into photodissociation of the Co-C bond in coenzyme B12

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    Coenzyme B12 (AdoCbl) is one of the most biologically active forms of vitamin B12, and continues to be a topic of active research interest. The mechanism of Co-C bond cleavage in AdoCbl, and the corresponding enzymatic reactions are however, not well understood at the molecular level. In this work, time-dependent density functional theory (TD-DFT) has been applied to investigate the photodissociation of coenzyme B12. To reduce computational cost, while retaining the major spectroscopic features of AdoCbl, a truncated model based on ribosylcobalamin (RibCbl) was used to simulate Co-C photodissociation. Equilibrium geometries of RibCbl were obtained by optimization at the DFT/BP86/TZVP level of theory, and low-lying excited states were calculated by TD-DFT using the same functional and basis set. The calculated singlet states, and absorption spectra were simulated in both the gas phase, and water, using the polarizable continuum model (PCM). Both spectra were in reasonable agreement with experimental data, and potential energy curves based on vertical excitations were plotted to explore the nature of Co-C bond dissociation. It was found that a repulsive 3(σCo-C → σ* Co-C) triplet state became dissociative at large Co-C bond distance, similar to a previous observation for methylcobalamin (MeCbl). Furthermore, potential energy surfaces (PESs) obtained as a function of both Co-CRib and Co-NIm distances, identify the S1 state as a key intermediate generated during photoexcitation of RibCbl, attributed to a mixture of a metal-to-ligand charge transfer (MLCT) and a s bonding-ligand charge transfer (SBLCT) states

    Komputeryzacja procesów gromadzenia zbiorów – z doświadczeń Biblioteki Głównej Uniwersytetu Marii Curie-Skłodowskiej w Lublinie

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    Collecting library resources is the basic task of every library, which translates into the quality of resources and user satisfaction. The article discusses the course of computerization of collection processes in the Main Library of the Maria Curie-Skłodowska University in Lublin. It was presented how the It tools used have changed since the 1990s and their impact on the organization of the work in the Department of Acquisition and Collection Development. In order to document the activities related to the discussed process, the following methods were used: document analysis and case study. The described experiences of the unit's employees may prove useful to other libraries.Gromadzenie zbiorów to podstawowe zadanie każdej biblioteki przekładające się na jakość zasobów i zadowolenie użytkowników. w artykule omówiono przebieg komputeryzacji procesów gromadzenia w Bibliotece Głównej Uniwersytetu Marii Curie-Skłodowskiej w Lublinie. przedstawiono, jak zmieniały się stosowane narzędzia informatyczne, począwszy od lat 90. XX wieku oraz ich wpływ na organizację pracy Oddziału Gromadzenia i Uzupełniania zbiorów. w celu udokumentowania działań związanych z omawianym procesem wykorzystano metody: analizy dokumentów oraz case study. Opisane doświadczenia pracowników jednostki mogą okazać się przydatne dla innych bibliotek

    Sequential sonographic features in neonatal renal vein thrombosis

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    Objectives: Renal vein thrombosis in newborns is a rare but serious and acute disease. Clinical representations of RVT can vary from discrete symptoms to life-threatening conditions. Therefore imaging, and in particular sonography, plays an important role in the diagnosis of RVT in neonates. Gray-scale, color and spectral/power Doppler ultrasound are all used in the diagnosis of RVT. Material and methods: We present retrospective sequential ultrasonic imaging of three patients (two term and one preterm infant) with findings characteristic of RVT. Results: Initial ultrasound diagnostic features include: renal enlargement, echogenic medullary streaks, lack of the flow pattern characteristic of arcuate vessels and subsequently loss of corticomedullary differentiation, reduced echogenicity around pyramids and echogenic band at the extreme apex of the pyramid. Higher resistance index or less pulsatile venous flow on the affected kidney are helpful Doppler signs. Conclusions: Knowledge and identification of specific features of each phase of the evolution of RTV seems essential to prompt diagnosis. We would like to highlight the evolution of specific sonographic features in each subsequent phase of RVT
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