11,667 research outputs found
Identification of bifunctional GA and AG intrastrand crosslinks formed between cisplatin and DNA
No full textA combination of enzymatic digestion and electrospray ionisation mass spectrometry (ESI-MS) was used to characterise bifunctional adducts in which cisplatin is bound to GA base sequences in 8mer and 16mer oligonucleotides that do not contain other, higher affinity binding sites. The extent of formation of bifunctional adducts with GA base sequences was significant, but less than that seen with similar oligonucleotides containing either AG or GG sequences
GA-Fuzzy PID control simulation waveform diagram.
No full textAs is well known, the metal annealing process has the characteristics of heat concentration and rapid heating. Traditional vacuum annealing furnaces use PID control method, which has problems such as high temperature fluctuation, large overshoot, and long response time during the heating and heating process. Based on this situation, some domestic scholars have adopted fuzzy PID control algorithm in the temperature control of vacuum annealing furnaces. Due to the fact that fuzzy rules are formulated through a large amount of on-site temperature data and experience summary, there is a certain degree of subjectivity, which cannot ensure that each rule is optimal. In response to this drawback, the author combined the technical parameters of vacuum annealing furnace equipment, The fuzzy PID temperature control of the vacuum annealing furnace is optimized using genetic algorithm. Through simulation and comparative analysis, it is concluded that the design of the fuzzy PID vacuum annealing furnace temperature control system based on GA optimization is superior to fuzzy PID and traditional PID control in terms of temperature accuracy, rise time, and overshoot control. Finally, it was verified through offline experiments that the fuzzy PID temperature control system based on GA optimization meets the annealing temperature requirements of metal workpieces and can be applied to the temperature control system of vacuum annealing furnaces.</div
In Situ Structure of Neuronal C9orf72 Poly-GA Aggregates Reveals Proteasome Recruitment
No full textProtein aggregation and dysfunction of the ubiquitin-proteasome system are hallmarks of many neuro-degenerative diseases. Here, we address the elusive link between these phenomena by employing cryo-electron tomography to dissect the molecular architecture of protein aggregates within intact neurons at high resolution. We focus on the poly-Gly-Ala (poly-GA) aggregates resulting from aberrant translation of an expanded GGGGCC repeat in C9orf72, the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. We find that poly-GA aggregates consist of densely packed twisted ribbons that recruit numerous 26S proteasome complexes, while other macromolecules are largely excluded. Proximity to poly-GA ribbons stabilizes a transient substrate-processing conformation of the 26S proteasome, suggesting stalled degradation. Thus, poly-GA aggregates may compromise neuronal proteostasis by driving the accumulation and functional impairment of a large fraction of cellular proteasomes
Increasing science, technology, engineering, and mathematics skills using Project Lead the Way
No full textIncludes bibliographical references
High-loading Ga-exchanged MFI zeolites as selective and coke-resistant catalysts for nonoxidative ethane dehydrogenation
No full textIn this paper, we investigated the effects of the Ga loading amount and H-2 treatment temperature for the reductive solid-state ion-exchange reaction on the generated Ga species in Ga-exchanged MFI zeolites (Ga-MFIs) as well as their catalysis for ethane dehydrogenation (EDH). For the formation of isolated Ga hydrides in the zeolites, [GaH](2+) ions were preferentially formed in the low-loading Ga-MFI (Ga/Al = 0.3) treated with H-2 at 550 degrees C, corresponding to the conventional preparation conditions, (Ga-MFI-0.3(550)), while the high Ga loading (Ga/Al = 1.0) and high-temperature H-2 treatment (800 degrees C) (Ga-MFI-1.0(800)) induced the formation of [GaH2](+) ions as the major Ga hydrides, as revealed by in situ Fourier transform infrared spectroscopy including the isotope experiment using D-2. In the context of other Ga species, such as Ga+ cations and partially reduced Ga oxides (GaOX), Ga+ cations and GaOX coexist in Ga-MFI-0.3(550), as indicated by pyridine adsorption experiments. On the other hand, GaOX was hardly observed and a larger amount of Ga+ cations was formed in Ga-MFI-1.0(800). The remaining Bronsted acid sites (BASs) were also characterized by the NH3 adsorption experiment. In the EDH reaction, Ga-MFI-1.0(800) exhibited high selectivity owing to low coke formation, resulting in the highest durability among the series of Ga-MFIs tested. Under the optimized conditions, Ga-MFI-1.0(800) exhibited the highest C2H4 formation rate among previously reported Pt-free catalysts. Based on the combined results of characterization, catalyst tests, and kinetic studies, the high selectivity and durability of Ga-MFI-1.0(800) can be ascribed to the low amount of the remaining BASs by isolated Ga species ([GaH](2+), [GaH2](+) ions and Ga+ cations) as well as the major formation of [GaH2](+) ions among isolated Ga hydrides
Element Distribution in Porous Ga Oxide Obtained by Anodizing Ga in Phosphoric Acid
No full textA STEM/EDS study of a porous Ga oxide film formed by an anodization process was conducted in this study to examine the crystalline structure of the film and the elemental distribution in the oxide film before and after heat treatment. The as-formed anodic film with a morphology resembling the well-known porous anodic Al oxide film was amorphous, crystallizing after heat treatment at 600 degrees C without changing the morphology and elemental distribution. The EDS elemental maps disclosed the duplex nature of the pore wall oxide; the phosphate anion was contaminated in the outer oxide layer next to the pores, and the inner layer consisted of relatively pure Ga oxide, practically free from phosphate. The similarity of morphology and elemental distributions between the porous anodic Al and Ga oxides suggests that the growth of both anodic oxide films proceeds under the same mechanism. In addition, crystallized porous Ga oxides are expected to be applied to fabricate various functional devices requiring geometrically controlled semiconductor nanohole arrays, such as devices for hydrogen formation. (c) 2023 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited
Effect of thermal treatments in Ni-Fe-Ga with Co substitutions and Ni-Mn-Ga melt spun ribbons
No full textAbstractThe effect of “in situ” thermal treatments (by DSC measurements) on the martensitic transformation in two representative Ni-Fe-Ga and Ni-Mn-Ga alloys has been studied and discussed by correlating the structural and magnetic properties. The alloys were prepared from high purity elements, by arc melting under argon protective atmosphere as bulk and also as melt-spun ribbons - an alternative preparation route that also allows to assess the influences of grains size and strain induced by this processing method. All samples presented reversible thermo-elastic transformations. The thermal treatments promote a reduction of the martensitic transformation temperatures in the Ni-Fe-Ga investigated samples, as opposed to the stoichiometric Ni2MnGa where the temperatures increase with increasing the annealing temperatures. Interestingly however, the off-stoichiometric Ni-Mn-Ga with increased Ni content recovers the behaviour with reduction of transformation temperatures by thermal treatments. The precipitation of the secondary FCC (γ) phase is inherently found in Ni-Fe-Ga alloys with Ga ≤ 27% at, and also -although in lower amounts- in the off-stoichiometric Ni-Mn-Ga. The γ phase is considered to contribute to the decrease of the MT temperatures (via valence electrons concentration depletion of the main matrix) and of the transformation heat as well as to the final structural degradation if the temperature of the thermal treatments is further increased. In addition, this phase, located mainly at the grain boundaries, is responsible for the improved ductility of Ni-Fe-Ga based alloys. Changes in the transformation heat due to thermal treatments are observed and discussed in both types of alloys, the maxima of the transformation heat being associated with the highest atomic order. Thermo-magnetic measurements show that Ni-Fe-Ga alloys have close magnetic and structural transitions temperatures, with promising applications for magnetic refrigeration
Using group interaction history in the wild
No full textInspired by theories of how professionals enter into a reflective conversation with their work materials, the research area of interaction history seeks to make use of the accumulated actions of many people in working with digital objects. Despite compelling system designs and empirical results in laboratory settings, group interaction histories have not been widely employed. I outline a series of research questions, plans and tools that will be among the first to investigate and evaluate the use of shared interaction history in the day-to-day work of individuals and groups
Improved tunneling magnetoresistance in (Ga,Mn)As/AlO(x)/CoFeB magnetic tunnel junctions
No full textWe fabricated (Ga,Mn)As/AlO(x)/Co(40)Fe(40)B(20) magnetic tunnel junctions with ferromagnetic semiconductor/insulator/ferromagnetic metal (S/I/F) structure. The treatments of pre-annealing and post-plasma cleaning on the (Ga,Mn) As film were introduced before the growth of the subsequent layers. A high tunneling magnetoresistance (TMR) ratio of 101% is achieved at 2 K, and the spin polarization of (Ga,Mn) As, P = 56.8%, is deduced from Julliere's formula. The improved TMR ratio is primarily due to the improved magnetism of (Ga,Mn) As layer by low-temperature annealing and cleaned interface between (Ga,Mn) As and AlO(x) attained by subsequent plasma cleaning process. (C) 2011 American Institute of Physics. [doi:10.1063/1.3603946
Fundamental Mechanisms Behind the Reverse Characteristic of Cu(In,Ga)Se<sub>2</sub> Solar Cells
No full textPartial shading of PV modules can lead to degradation of the shaded cells. The degradation originates from a reverse bias voltage over the shaded cells. In order to mitigate reverse bias damage in Cu(In, Ga)Se2 (CIGS) modules, a good understanding of the fundamental mechanisms governing the reverse characteristic is required. In this study, a model is introduced that describes this behavior for CIGS cells. In this model, the low and non-Ohmic leakage current is accounted for by the space charge limited current component. A sharp increase in current that is typically observed in the CIGS reverse characteristics can be described by Fowler-Nordheim tunneling. This model has been validated against measurements performed at different temperatures and illumination intensities, and is able to describe the dependencies of the reverse bias behavior on both temperature and illumination.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Photovoltaic Materials and Device
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