107 research outputs found

    Umm el-Marra and the Western Expansion of the Mittani Empire in Northwestern Syria

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    The Bronze Age occupation of Umm el-Marra, a medium-sized regional center in western Syria, lasted, with varying degrees of intensity, for more than a millennium. During this time, the communities who inhabited the site and the political regimes that ruled them left their unique marks on the built environment and material culture. This dissertation studies these phenomena during the Late Bronze Age occupation of Umm el-Marra in the mid-second millennium through a synthesis of the excavation records of the site, archaeological comparanda, textual evidence, ethnoarchaeology, and applicable theory. The Mittani Empire was the dominant power in northern Syria during the Late Bronze occupation of Umm el-Marra. Most of what is known about Mittani comes from external sources, many of whom were antagonistic and, thus, provide a biased view of the empire and its inhabitants. Through analysis of the Late Bronze Age levels at Umm el-Marra, this work provides an evaluation and exploration of the nature of everyday life in the Mittani empire. As such, it offers a new resource for understanding Mittani, in particular, and the functioning of imperial regimes in general, from the perspective of daily lived existence in households, neighborhoods, and a specific community. As communities and their constituent families change over time, they have different needs of the dwellings and landscapes they inhabit. These shifting needs are often reflected in the built environment. In this dissertation, I approach the interpretation of the excavated data through a temporal rubric to create a better understanding of how the members of the Late Bronze Age community of Umm el-Marra experienced their world. This dissertation suggests that the Late Bronze Age occupation of Umm el-Marra was an attempt by Mittani to create a node of control on the Jabbul Plain to help incorporate the region into the empire. The fortunes of Late Bronze Age Umm el-Marra rose and fell with those of Mittani. Both waning political fortunes and the community’s internal demographic shifts led to the gradual abandonment of much of the site before its destruction. This archaeologically visible process sheds light on the life-cycle of communities and the nature of abandonment

    ELECTROMAGNETIC SHIELDING GLASS

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    Results of the development of electromagnetic shielding glass compositions for protection against electromagnetic radiation are given in this work

    Stationary States of Dissipative Quantum Systems

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    In this Letter we consider stationary states of dissipative quantum systems. We discuss stationary states of dissipative quantum systems, which coincide with stationary states of Hamiltonian quantum systems. Dissipative quantum systems with pure stationary states of linear harmonic oscillator are suggested. We discuss bifurcations of stationary states for dissipative quantum systems which are quantum analogs of classical dynamical bifurcations.Comment: 10 pages, LaTe

    Piezoelectric thin-film super-lattices without using piezoelectric materials

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    Abstract: In this paper we show that experimentally realizable apparently piezoelectric thin-film super-lattices can be created from non-piezoelectric materials provided an odd-order (e.g. trilayer) stacking sequence is used. The size-dependent mechanism of flexoelectricity, which couples gradients of strain to polarization, allows such a possibility. We present closed-form analytical expressions for the response of various thin-film and super-lattice configurations. We also clarify some of the subtleties that arise in considering interface boundary conditions in the theory of flexoelectricity as well as the relationship of flexoelectricity to the frequently used polarization gradient terms used in modeling ferroelectrics. We find that for certain (optimum) material combinations and length scales, thin film superlattices yielding apparent piezoelectricity close to 75 % of ferroelectric Barium Titanate may be achievable

    DEVELOPMENT OF HEAT-RESISTANT GLASS COMPOSITIONS

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    Results of the development of refractory and heat-resistant glass compositions for a glazing of fireplaces are given in this work

    Spectral Properties of Thioflavin T and Its Complexes with Amyloid Fibrils

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    Comparative analysis of the absorption and fluorescence spectra and fluorescence excitation spectra of thioflavin T (ThT) in various solvents and in the composition of amyloid fibrils has shown that ThT, when excited in the region of the long-wavelength absorption band, fluoresces in the spectral region with a maximum at 478–484 nm. The appearance in aqueous and alcohol solutions of a fluorescence band with a maximum near 440 nm has been attributed to the presence in the composition of the ThT preparations of an impurity with an absorption band in the 340–350-nm range. The literature data showing that in glycerol ThT has a wide fluorescence spectrum with two maxima are due to the artifact connected with the use of a high concentration of the dye. It has been suggested that the cause of the low quantum yield of ThT aqueous and alcohol solutions is the breakage of the system of conjugated bonds due to the reorientation of the benzothiozole and benzaminic rings of ThT in the excited state with respect to one another. The main factor determining the high quantum yield of fluorescence of ThT incorporated in fibrils is the steric restriction of the rotation of the rings about one another under these conditions. The suggestions made have been verified by the quantum-chemical calculation of the ThT molecule geometry in the ground and excited states

    Fluorescence Quantum Yield of Thioflavin T in Rigid Isotropic Solution and Incorporated into the Amyloid Fibrils

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    In this work, the fluorescence of thioflavin T (ThT) was studied in a wide range of viscosity and temperature. It was shown that ThT fluorescence quantum yield varies from 0.0001 in water at room temperature to 0.28 in rigid isotropic solution (T/η→0). The deviation of the fluorescence quantum yield from unity in rigid isotropic solution suggests that fluorescence quantum yield depends not only on the ultra-fast oscillation of ThT fragments relative to each other in an excited state as was suggested earlier, but also depends on the molecular configuration in the ground state. This means that the fluorescence quantum yield of the dye incorporated into amyloid fibrils must depend on its conformation, which, in turn, depends on the ThT environment. Therefore, the fluorescence quantum yield of ThT incorporated into amyloid fibrils can differ from that in the rigid isotropic solution. In particular, the fluorescence quantum yield of ThT incorporated into insulin fibrils was determined to be 0.43. Consequently, the ThT fluorescence quantum yield could be used to characterize the peculiarities of the fibrillar structure, which opens some new possibilities in the ThT use for structural characterization of the amyloid fibrils

    Резонансное усиление флуоресценции квантовых точек у поверхности плазмонных пленок

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    Effective enhancement of the fluorescence signal of chromophores adsorbed directly onto plasmonic films can be observed under conditions of strong spectral resonance between plasmon and chromophore absorptions. This effect seems to contradict the established mechanisms of complete quenching of the fluorescence of chromophores under their adsorbtion directly onto the metal surface. However, under certain conditions, enhancement of the fluorescence signal is observed for both inorganic and organic chromophores. To understand the effect and conditions of its observation, we propose to use the quantum concept of virtual photon exchange in the near optical field - dressed photons. This concept is borrowed from the physics of elementary particles and is already well adapted to the problems of nanophotonics by M. Otsu. In this paper, we discuss exclusively the key factors responsible for enhancement of fluorescence of CdSe/ZnS nanocrystals and the effective dressed photons exchange: the size of nanoparticles, the distance between them, and the presence of spectral overlap indicating the possibility of resonant interactions between plasmons and chromophores.Communicated by Academician Sergei V. GaponenkoЭффективное усиление сигнала флуоресценции хромофоров, адсорбированных непосредственно на плазмонные пленки (ПП), можно наблюдать в условиях сильного спектрального резонанса между плазмонным поглощением и поглощением хромофора. Указанный эффект, на первый взгляд, противоречит установленным механизмам полного тушения флуоресценции хромофоров при их адсорбции непосредственно на поверхность металла. Однако при определенных условиях усиление сигнала флуоресценции наблюдается как для неорганических, так и органических хромофоров. Для понимания эффекта и условий, при которых он может наблюдаться, мы предлагаем исходить из двух основополагающих факторов, определяющих вероятности квантовых переходов, - матричного элемента перехода, ответственного за наблюдаемое излучение, и плотности конечных состояний. Однако при определении матричного элемента перехода необходимо учитывать наличие нескольких хромофорных систем (адсорбированные хромофоры и локализованные плазмоны), способных поглощать возбуждающее излучение и еще одной плазмон-поляритонной системы, имеющей светоподобную природу и способной к излучению световых квантов, а также взаимодействие между ними, которое может быть описано в рамках обмена виртуальными фотонами. Учитывая, что расстояния между наночастицами намного меньше длины волны света и дипольное приближение не работает, мы предлагаем использовать квантовую концепцию обмена виртуальными фотонами в ближнем оптическом поле - «одетыми» фотонами. Эта концепция заимствована из физики элементарных частиц и уже хорошо адаптирована к проблемам нанофотоники М. Отсу. Второй фактор, который также может давать значительный вклад в усиление, - это модификация плотности как электронных, так и фотонных состояний - эффект, который предложен С. В. Гапоненко в качестве модели, ответственной за усиление гигантского комбинационного рассеяния света хромофоров в стоксовой и антистоксовой области вблизи наночастиц с плазмонными свойствами. В данной работе обсуждаются такие ключевые факторы, ответственные за усиление флуоресценции наночастиц CdSe/ZnS и эффективный обмен виртуальными фотонами, как размер наночастиц, расстояния между ними и наличие спектрального перекрытия, указывающего на возможность резонансных взаимодействий между плазмонами и хромофорами.Представлено академиком С.В. Гапоненк

    Morphology-Specific Inhibition of β-Amyloid Aggregates by 17β-Hydroxysteroid Dehydrogenase Type 10

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    A major hallmark of Alzheimer's disease (AD) is the formation of toxic aggregates of the β-amyloid peptide (Aβ). Given that Aβ peptides are known to localise within mitochondria and interact with 17β-HSD10, a mitochondrial protein expressed at high levels in AD brains, we investigated the inhibitory potential of 17β-HSD10 against Aβ aggregation under a range of physiological conditions. Fluorescence self-quenching (FSQ) of Aβ(1-42) labelled with HiLyte Fluor 555 was used to evaluate the inhibitory effect under conditions established to grow distinct Aβ morphologies. 17β-HSD10 preferentially inhibits the formation of globular and fibrillar-like structures but has no effect on the growth of amorphous plaque-like aggregates at endosomal pH 6. This work provides insights into the dependence of the Aβ-17β-HSD10 interaction with the morphology of Aβ aggregates and how this impacts enzymatic function. 17 β-HSD10 interaction with Aβ amyloid: what type of amyloid? 17β-hydroxysteroid dehydrogenase type 10 interacts with β-amyloid (Aβ) aggregates and suppresses Aβ-induced apoptosis in neurons, but the aggregate morphology inhibited by 17β-HSD10 remains unknown. Fluorescence self-quenching demonstrated that fibrils and globular aggregates, but not plaques, are targeted by 17β-HSD10
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