Search results for "Dop"
showing 10 items of 4870 documents
Ab initio calculations of pure and Co+2-doped MgF2 crystals
2020
This research was partly supported by the Kazakhstan Science Project № AP05134367«Synthesis of nanocrystals in track templates of SiO2/Si for sensory, nano- and optoelectronic applications», as well as by Latvian Research Council project lzp-2018/1-0214. Calculations were performed on Super Cluster (LASC) in the Institute of Solid State Physics (ISSP) of the University of Latvia. Authors are indebted to S. Piskunov for stimulating discussions.
Constitutive and regulated α-secretase cleavage of Alzheimer’s amyloid precursor protein by a disintegrin metalloprotease
1999
Amyloid β peptide (Aβ), the principal proteinaceous component of amyloid plaques in brains of Alzheimer’s disease patients, is derived by proteolytic cleavage of the amyloid precursor protein (APP). Proteolytic cleavage of APP by a putative α-secretase within the Aβ sequence precludes the formation of the amyloidogenic peptides and leads to the release of soluble APPsα into the medium. By overexpression ofa disintegrinandmetalloprotease (ADAM), classified as ADAM 10, in HEK 293 cells, basal and protein kinase C-stimulated α-secretase activity was increased severalfold. The proteolytically activated form of ADAM 10 was localized by cell surface biotinylation in the plasma membrane, but the m…
Down-regulation of Endogenous Amyloid Precursor Protein Processing due to Cellular Aging
2005
Processing of amyloid precursor protein (APP) is a well acknowledged central pathogenic mechanism in Alzheimer disease. However, influences of age-associated cellular alterations on the biochemistry of APP processing have not been studied in molecular detail so far. Here, we report that processing of endogenous APP is down-regulated during the aging of normal human fibroblasts (IMR-90). The generation of intracellular APP cleavage products C99, C83, and AICD gradually declines with increasing life span and is accompanied by a reduced secretion of soluble APP (sAPP) and sAPPalpha. Further, the maturation of APP was reduced in senescent cells, which has been shown to be directly mediated by a…
Quimiosensores y quimiodosímetros para la detección de neurotransmisores
2019
La presente Tesis Doctoral titulada “Quimiosensores y quimiodosímetros para la detección de neurotransmisores” está centrada en el desarrollo de nuevos sistemas para la detección cromogénica y fluorogénica de moléculas biógenas, haciendo especial hincapié en el uso del fenómeno conocido como Emisión Inducida por Agregación (AIE) como mecanismo de transducción. Para ello, se han sintetizado y estudiado una serie de derivados del tetrafenileteno (TPE), compuesto que presenta propiedades AIE que pueden ser modificadas fácilmente gracias a la adecuada funcionalización del mismo. En el capítulo 3 se describe cómo, en derivados del TPE funcionalizados con anillos de triazol sustituidos con cadena…
The Arabidopsis heavy metal P-type ATPase HMA5 interacts with metallochaperones and functions in copper detoxification of roots
2005
*† ‡ § Summary Since copper (Cu) is essential in key physiological oxidation reactions, organisms have developed strategies for handling Cu while avoiding its potentially toxic effects. Among the tools that have evolved to cope with Cu is a network of Cu homeostasis factors such as Cu-transporting P-type ATPases that play a key role in transmembrane Cu transport. In this work we present the functional characterization of an Arabidopsis Cutransporting P-type ATPase, denoted heavy metal ATPase 5 (HMA5), and its interaction with Arabidopsis metallochaperones. HMA5 is primarily expressed in roots, and is strongly and specifically induced by Cu in whole plants. We have identified and characteriz…
Median arcuate ligament syndrome, a rare case of chronic abdominal pain
2018
The median arcuate ligament syndrome (MALS) is a rare disease characterized by abdominal pain caused by the external compression of the celiac artery by the median arcuate ligament. Surgical treatment is indicated, but given the non-specific symptoms, these patients are often hospitalized in the Departments of Internal Medicine where the diagnosis may be unknown. We present a case of MALS admitted to our Internal Medicine Division. An abdominal ultrasound in a woman with longstanding abdominal pain showed elevated celiac artery velocities during forced expiration. Computed tomography angiography (CTA) of the abdomen showed stenosis of the origin of the celiac artery and confirmed the diagno…
Progetti di lessicografia onomastica dell’Atlante Linguistico della Sicilia
2022
L’Atlante Linguistico della Sicilia ha adottato, già una decina di anni fa, lo strumento del dizionario-atlante. Quando si è cominciato ad indagare il ricco universo onomastico, se ne è valutata la spendibilità anche su tre diversi corpora orali: uno relativo alle forme popolari del patrimonio toponomastico (DAToS, Dizionario-atlante toponomastico della Sicilia), uno riguardante l’inventario plurale dei soprannomi etnici (DASES, Dizionario-atlante dei soprannomi etnici in Sicilia), l’ultimo afferente al patrimonio antroponomastico popolare, individuale e familiare (DASS, Dizionario-atlante dei soprannomi di/in Sicilia). Il contributo fornisce lo stato dell’arte dei tre progetti e ne descriv…
Residual water and electrical properties of polyaniline
1994
Summary form only given. The work aims to study the mechanism of interaction between water molecules and polyaniline (PANI) backbone as an important constituent of acid-base transformations ensuring good conductive properties of PANI. Experiments have been made using chemically synthesized emeraldine base subjected to different chemical treatments and aging procedures. Thermogravimetric measurement have shown that water content in polymeric matrices may amount up to 20-25 wt.% with two distinguished reversible absorbance states of water molecules. Weakly bond water (3-5 kcal/mol) is incorporated into PANI from ambient atmosphere and could be eliminated by drying at room temperature in vacuu…
[Pt2Cu34(PET)22Cl4]2–: An Atomically Precise, 10-Electron PtCu Bimetal Nanocluster with a Direct Pt–Pt Bond
2021
Heteroatom-doped metal nanoclusters (NCs) are highly desirable to gain fundamental insights into the effect of doping on the electronic structure and catalytic properties. Unfortunately, their controlled synthesis is highly challenging when the metal atomic sizes are largely different (e.g., Cu and Pt). Here, we design a metal-exchange strategy that enables simultaneous doping and resizing of NCs. Specifically, [Pt2Cu34(PET)22Cl4]2- NC, the first example of a Pt-doped Cu NC, is synthesized by utilizing the unique reactivity of [Cu32(PET)24Cl2H8]2- NC with Pt4+ ions. The single-crystal X-ray structure reveals that two directly bonded Pt atoms occupy the two centers of an unusually interpenet…
The role of Fe and Cu dopants in electron–hole trapping and relaxation process in congruent LiNbO3
2003
Abstract The transient optical absorption and kinetics of absorption decay is studied in undoped, Fe doped, and Cu doped LiNbO 3 crystals irradiated by pulsed electron beam. The 1.6 eV band of electron polaron trapped at antisite niobium was observed in all crystal samples. The nature of centers responsible for transient absorption is discussed. Electron polarons are shown to be less stable in LiNbO 3 :Fe compared with LiNbO 3 :Cu and undoped LiNbO 3 . It is suggested that a major part of electrons and holes created by irradiation are trapped in the vicinity of dopants.