889 research outputs found
Moorish Revival Synagogue Architecture: Community and Style, Past and Present
The Moorish architectural style, originating in medieval Spain, was revived in the mid-nineteenth century. It became strongly linked with synagogues, first in Germany and then throughout the Western world. My research analyzes why the architects and Jewish communities were so attracted to the Moorish Revival style. During this period, European Jewish communities were tasked with constructing synagogues that could showcase their newfound freedoms as well as their history, culture and aspirations. Many argue that this style was chosen to demonstrate the connection between the communities and their ancient Middle Eastern history
A GPU-based finite-size pencil beam algorithm with 3D-density correction for radiotherapy dose calculation
Targeting at the development of an accurate and efficient dose calculation
engine for online adaptive radiotherapy, we have implemented a finite size
pencil beam (FSPB) algorithm with a 3D-density correction method on GPU. This
new GPU-based dose engine is built on our previously published ultrafast FSPB
computational framework [Gu et al. Phys. Med. Biol. 54 6287-97, 2009].
Dosimetric evaluations against Monte Carlo dose calculations are conducted on
10 IMRT treatment plans (5 head-and-neck cases and 5 lung cases). For all
cases, there is improvement with the 3D-density correction over the
conventional FSPB algorithm and for most cases the improvement is significant.
Regarding the efficiency, because of the appropriate arrangement of memory
access and the usage of GPU intrinsic functions, the dose calculation for an
IMRT plan can be accomplished well within 1 second (except for one case) with
this new GPU-based FSPB algorithm. Compared to the previous GPU-based FSPB
algorithm without 3D-density correction, this new algorithm, though slightly
sacrificing the computational efficiency (~5-15% lower), has significantly
improved the dose calculation accuracy, making it more suitable for online IMRT
replanning
Effect of Statistical Fluctuation in Monte Carlo Based Photon Beam Dose Calculation on Gamma Index Evaluation
The gamma-index test has been commonly adopted to quantify the degree of
agreement between a reference dose distribution and an evaluation dose
distribution. Monte Carlo (MC) simulation has been widely used for the
radiotherapy dose calculation for both clinical and research purposes. The goal
of this work is to investigate both theoretically and experimentally the impact
of the MC statistical fluctuation on the gamma-index test when the fluctuation
exists in the reference, the evaluation, or both dose distributions. To the
first order approximation, we theoretically demonstrated in a simplified model
that the statistical fluctuation tends to overestimate gamma-index values when
existing in the reference dose distribution and underestimate gamma-index
values when existing in the evaluation dose distribution given the original
gamma-index is relatively large for the statistical fluctuation. Our numerical
experiments using clinical photon radiation therapy cases have shown that 1)
when performing a gamma-index test between an MC reference dose and a non-MC
evaluation dose, the average gamma-index is overestimated and the passing rate
decreases with the increase of the noise level in the reference dose; 2) when
performing a gamma-index test between a non-MC reference dose and an MC
evaluation dose, the average gamma-index is underestimated when they are within
the clinically relevant range and the passing rate increases with the increase
of the noise level in the evaluation dose; 3) when performing a gamma-index
test between an MC reference dose and an MC evaluation dose, the passing rate
is overestimated due to the noise in the evaluation dose and underestimated due
to the noise in the reference dose. We conclude that the gamma-index test
should be used with caution when comparing dose distributions computed with
Monte Carlo simulation
Comparative Study of Bi-Te-Se-S Mineralizations in Slovak Republic and Transcarpathian Region of Ukraine. Part 1. Localities, Geological Situation and Mineral Associations
Comparative analysis of telluride occurrences found in the territory of Slovakia and Transcarpathians (Ukraine) has shown that there is distinct difference between the mode of Au-Ag-Bi-Te-Se mineralization of these regions. But within the area of distribution of neovolcanites Bi-Te-Se-S mineralization is generally represented by similar mineralogical phases. In the Transcarpathian region bismuth tellurides (tsumoite, pilsenite, joseites, native bismuth and poorly studied sulpho-selenotellurides of bismuth) were found only in metasomatites as secondary quartzites of the Vyghorlat-Guta ridge area. (Il'kivtsy, Podulky, Smerekiv Kamin'). The similar mineralization have been also found in some neovolcanites of Slovakia (Poruba pod Vigorlatom, Remetska Hamra).Порівняльний аналіз проявів телуридів на території Словаччини і Закарпаття (Україна) показав, що існує помітна відмінність в характері Au-Ag-Bi-Te-Se мінералізації цих регіонів. Але в областях розвитку неовулканітів Bi-Te-Se-S мінералізація представлена в основному аналогічними мінеральними фазами. Телуриди вісмуту (цумоїт, пильзеніт, жозеїти, самородний бісмут і маловивчені сульфо-селено-телуриди бісмуту) знайдені на території Закарпаття тільки в метасоматитах типу вторинних кварцитів Вигорлат-Гутинського пасма (Ільківці, Подулки, Смереків Камінь). Подібна мінералізація встановлена в деяких неовулканітах Словаччини (Poruba роd Vigorlatom, Remetska Hamra).Сравнительный анализ проявлений теллуридов на территории Словакии и Закарпатья (Украина) показал, что существует заметное различие в характере Au-Ag-Bi-Te-Se минерализации этих регионов. Но в областях развития неовулканитов Bi-Te-Se-S минерализация представлена в основном аналогичными минеральными фазами. Теллуриды висмута (цумоит, пильзенит, жозеиты, самородный висмут и малоизученные сульфо-селенотеллуриды висмута) найдены на территории Закарпатья только в метасоматитах типа вторичных кварцитов Выгорлат-Гутинской гряды (Ильковцы, Подулки, Смерекив Каминь). Подобная минерализация установлена в некоторых неовулканитах Словакии (Poruba pod Vigorlatom, Remetska Hamra)
Electronic transport properties of the Al0.5TiZrPdCuNi alloy in the high-entropy alloy and metallic glass forms
High-entropy alloys (HEAs) are characterized by a simultaneous presence of a crystal lattice and an amorphous-type chemical (substitutional) disorder. In order to unravel the effect of crystal-glass duality on the electronic transport properties of HEAs, we performed a comparative study of the electronic transport coefficients of a 6-component alloy Al0.5TiZrPdCuNi that can be prepared either as a HEA or as a metallic glass (MG) at the same chemical composition. The HEA and the MG states of the Al0.5TiZrPdCuNi alloy both show large, negative-temperature-coefficient resistivity, positive thermopower, positive Hall coefficient and small thermal conductivity. The transport coefficients were reproduced analytically by the spectral conductivity model, using the Kubo-Greenwood formalism. For both modifications of the material (HEA and MG), contribution of phonons to the transport coefficients was found small, so that their temperature dependence originates predominantly from the temperature dependence of the Fermi-Dirac function and the variation of the spectral conductivity and the related electronic density of states with energy within the Fermi-level region. The very similar electronic transport coefficients of the HEA and the MG states point towards essential role of the immense chemical disorder
Structure and superconductivity of tin-containing hftizrsnm (M = cu, fe, nb, ni) medium-entropy and high-entropy alloys
In an attempt to incorporate tin (Sn) into high-entropy alloys composed of refractory metals Hf, Nb, Ti and Zr with the addition of 3d transition metals Cu, Fe, and Ni, we synthesized a series of alloys in the system HfTiZrSnM (M = Cu, Fe, Nb, Ni). The alloys were characterized crystallographically, microstructurally, and compositionally, and their physical properties were determined, with the emphasis on superconductivity. All Sn-containing alloys are multi-phase mixtures of intermetallic compounds (in most cases four). A common feature of the alloys is a microstructure of large crystalline grains of a hexagonal (Hf, Ti, Zr)5Sn3 partially ordered phase embedded in a matrix that also contains many small inclusions. In the HfTiZrSnCu alloy, some Cu is also incorporated into the grains. Based on the electrical resistivity, specific heat, and magnetization measurements, a superconducting (SC) state was observed in the HfTiZr, HfTiZrSn, HfTiZrSnNi, and HfTiZrSnNb alloys. The HfTiZrSnFe alloy shows a partial SC transition, whereas the HfTiZrSnCu alloy is non-superconducting. All SC alloys are type II superconductors and belong to the Anderson class of “dirty” superconductors
DNA hybridization on membrane-modified carbon electrodes
The DNA-modified membrane electrode was prepared by casting a mixture of nitrocellulose (NC) with target DNA (tDNA) in organic solvent on glassy carbon electrode (GCE). Unlabeled polymerase chain reaction (PCR)-amplified human genomic sequence (628 bp) or synthetic oligodeoxynucleotides (ODNs) were used as tDNAs, creating a recognition layer. Biotinylated ODNs were used as hybridization probes to recognize specific nucleotide sequences. The hybridization events were detected via an enzyme-linked electrochemical assay involving binding of streptavidin-coupled alkaline phosphatase (SALP) to the biotin labels of the probe bound to tDNA. After the probe hybridization and SALP binding, the electrode was immersed into an electroinactive enzyme substrate (1-naphthyl phosphate). The alkaline phosphatase converted the inactive substrate into electroactive 1-naphthol that penetrated through the NC membrane to the GCE surface and was subsequently detected using an anodic voltammetric signal. The optimized method offered a good discrimination between complementary and nonspecific DNAs and yielded well-defined responses for both single-copy and repetitive tDNA sequences. In contrast to previously published methods using electrodes with mechanically attached membranes, the previously mentioned electrode is easily amenable to parallel DNA analysis. Copyright © Taylor & Francis, Inc
Dysregulation of principal cell miRNAs facilitates epigenetic regulation of AQP2 and results in nephrogenic diabetes insipidus
Background MicroRNAs (miRNAs), formed by cleavage of pre-microRNA by the endoribonuclease Dicer, are critical modulators of cell function by post-transcriptionally regulating gene expression. Methods Selective ablation of Dicer in AQP2-expressing cells (DicerAQP2Cre1 mice) was used to investigate the role of miRNAs in the kidney collecting duct of mice. Results The mice had severe polyuria and nephrogenic diabetes insipidus, potentially due to greatly reduced AQP2 and AQP4 levels. Although epithelial sodium channel levels were decreased in cortex and increased in inner medulla, amiloride-sensitive sodium reabsorption was equivalent in DicerAQP2Cre1 mice and controls. Small-RNA sequencing and proteomic analysis revealed 31 and 178 significantly regulated miRNAs and proteins, respectively. Integrated bioinformatic analysis of the miRNAome and proteome suggested alterations in the epigenetic machinery and various transcription factors regulating AQP2 expression in DicerAQP2Cre1 mice. The expression profile and function of three miRNAs (miR-7688-5p, miR-8114, and miR-409-3p) whose predicted targets were involved in epigenetic control (Phf2, Kdm5c, and Kdm4a) or transcriptional regulation (GATA3, GATA2, and ELF3) of AQP2 were validated. Luciferase assays could not demonstrate direct interaction of AQP2 or the three potential transcription factors with miR-7688-5p, miR-8114, and miR-409-3p. However, transfection of respective miRNA mimics reduced AQP2 expression. Chromatin immunoprecipitation assays demonstrated decreased Phf2 and significantly increased Kdm5c interactions at the Aqp2 gene promoter in DicerAQP2Cre1 mice, resulting in decreased RNA Pol II association. Conclusions Novel evidence indicates miRNA-mediated epigenetic regulation of AQP2 expression
An intronic microRNA silences genes that are functionally antagonistic to its host gene
MicroRNAs (miRNAs) are short noncoding RNAs that down-regulate gene expression by silencing specific target mRNAs. While many miRNAs are transcribed from their own genes, nearly half map within introns of ‘host’ genes, the significance of which remains unclear. We report that transcriptional activation of apoptosis-associated tyrosine kinase (AATK), essential for neuronal differentiation, also generates miR-338 from an AATK gene intron that silences a family of mRNAs whose protein products are negative regulators of neuronal differentiation. We conclude that an intronic miRNA, transcribed together with the host gene mRNA, may serve the interest of its host gene by silencing a cohort of genes that are functionally antagonistic to the host gene itself
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