20 research outputs found
Identification of novel elements of the Drosophila blisterome sheds light on potential pathological mechanisms of several human diseases.
Main developmental programs are highly conserved among species of the animal kingdom. Improper execution of these programs often leads to progression of various diseases and disorders. Here we focused on Drosophila wing tissue morphogenesis, a fairly complex developmental program, one of the steps of which - apposition of the dorsal and ventral wing sheets during metamorphosis - is mediated by integrins. Disruption of this apposition leads to wing blistering which serves as an easily screenable phenotype for components regulating this process. By means of RNAi-silencing technique and the blister phenotype as readout, we identify numerous novel proteins potentially involved in wing sheet adhesion. Remarkably, our results reveal not only participants of the integrin-mediated machinery, but also components of other cellular processes, e.g. cell cycle, RNA splicing, and vesicular trafficking. With the use of bioinformatics tools, these data are assembled into a large blisterome network. Analysis of human orthologues of the Drosophila blisterome components shows that many disease-related genes may contribute to cell adhesion implementation, providing hints on possible mechanisms of these human pathologies
Golgi-Resident Gαo Promotes Protrusive Membrane Dynamics.
To form protrusions like neurites, cells must coordinate their induction and growth. The first requires cytoskeletal rearrangements at the plasma membrane (PM), the second requires directed material delivery from cell's insides. We find that the Gαo-subunit of heterotrimeric G proteins localizes dually to PM and Golgi across phyla and cell types. The PM pool of Gαo induces, and the Golgi pool feeds, the growing protrusions by stimulated trafficking. Golgi-residing KDELR binds and activates monomeric Gαo, atypically for G protein-coupled receptors that normally act on heterotrimeric G proteins. Through multidimensional screenings identifying > 250 Gαo interactors, we pinpoint several basic cellular activities, including vesicular trafficking, as being regulated by Gαo. We further find small Golgi-residing GTPases Rab1 and Rab3 as direct effectors of Gαo. This KDELR → Gαo → Rab1/3 signaling axis is conserved from insects to mammals and controls material delivery from Golgi to PM in various cells and tissues
Fully porous GaN p-n junction diodes fabricated by chemical vapor deposition
Producción CientíficaModern society is experiencing an ever-increasing demand for energy to power a vast array of electrical and mechanical devices. A significant amount of the energy consumed is used for lighting purposes. For instance, this demand is ~17% of the total energy consumed in the USA in 2011 [1]. Thus, any approach that can reduce energy consumption is important. In this context, the development of light emitting diodes (LEDs) incorporating at least one porous component, with improved light extraction efficiency, is being explored intensively [2]. However, up to now, only partially porous p-n junctions have been analyzed for this purpose.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA166A11-2 and VA293U1
Fabrication of p-type porous GaN on silicon and epitaxial GaN
Abstract : Porous GaN layers are grown on silicon from gold or platinum catalyst seed layers, and self-catalyzed on epitaxial GaN films on sapphire. Using a Mg-based precursor, we demonstrate p-type doping of the porous GaN. Electrical measurements for p-type GaN on Si show Ohmic and Schottky behavior from gold and platinum seeded GaN, respectively. Ohmicity is attributed to the formation of a Ga2Au intermetallic. Porous p-type GaN was also achieved on epitaxial n-GaN on sapphire, and transport measurements confirm a p-n junction commensurate with a doping density of 1018 cm 3. Photoluminescence and cathodoluminescence confirm emission from Mg-acceptors in porous p-type GaN
Fully porous GaN p-n junctions fabricated by Chemical Vapor Deposition: a green technology towards more efficient LEDs
Producción CientíficaPorous GaN based LEDs produced by corrosion etching techniques
demonstrated enhanced light extraction efficiency in the past.
However, these fabrication techniques require further postgrown
processing steps, which increase the price of the final system. In
this paper, we review the process followed towards the fabrication
of fully porous GaN p-n junctions directly during the growth step,
using a sequential chemical vapor deposition (CVD) process to
produce the different layers that form the p-n junction.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13
Обеспечение надежности головных подшипников судовых малооборотных двигателей, работающих на режимах частичных нагрузок
The paper analyzes the causes of damage to the head bearings of low-speed marine engines of MAN B & W, mainly operating under partial load conditions. It has been established that diesel engines bearings with installed TCCO systems (Turbocharger Cut-Out) are the most damaging. TCCO systems allow gas turbochargers (TC) to be withdrawn from service in order to increase the productivity of the remaining turbochargers and reduce the specific fuel consumption. The results of a dynamic analysis of loading conditions for a bearing assembly are presented using the example of the 12K98MC engine for 100% and 50% Nen modes. It is established that the maximum force acting on the crosshead is 7755 kN and arises at the position of the crankshaft at an angle j = 205 ° and the angle of deflection of the connecting rod β = 8 °. In the operating mode of the engine 12K98MC-C6 100% Nen, no forces occurs in the crank mechanism, which help unload the lower bearing of the head bearing. The authors refute the assumption that there are damages to the antifriction layer of fatigue bearing. It is assumed that the main cause of such damage is the violation of the hydrodynamic lubrication regime with a decrease in the engine speed of the crankshaft. It is indicated the need to change the design of the lower bearing shell of the head bearing in order to increase the bearing capacity. A simplified 3D model of connecting rod and crosshead bearing was developed without a central oil distribution groove. The results of numerical modeling of the contact conditions of the upgraded version of the lower bearing of the head bearing are presented and the character of stress distribution and deformation in the volumes of the AlSn40 antifriction material is studied. It is established that the maximum pressure zones are located in the central part of the liner and in its peripheral areas. The obtained results of the investigation of the stressed-deformed state of the lower liner indicate the need to eliminate the axial oil distribution groove and the manufacture of axial oil distribution grooves under a total angle of 68 ... 72 °. The proposed version of the lower liner design at the engine operating mode of 100% Nen senses the maximum stresses and relative deformations in the bearing antifriction material 28 MPa and 22,5 ½ 10-3 respectively. В работе приведён анализ причин повреждения головных подшипников малооборотных судовых двигателей фирмы MAN B&W, преимущественно работающих на режимах частичных нагрузок. Представлены результаты динамического анализа условий нагружения подшипникового узла на примере двигателя 12K98MC. Авторами опровергается предположение наличия повреждений антифрикционного слоя подшипников усталостного характера. Приведены результаты численного моделирования условий контакта модернизированного варианта нижнего вкладыша головного подшипника. Представлены результаты исследования напряжённо-деформированного состояния нижнего вкладыша и рекомендации по оптимизации его конструкции.
The Influence of Technological Parameters of X70 Stainless Steel Ladle Refining on the Residual Content of Non-Metallic Inclusions
It is demonstrated that during secondary refining at the ladle furnace the carbon content of steel and the residence time of the metal in the ladle exert a significant impact on the residual content of non-metallic inclusions (NMI) in steel. Mathematical calculations showed that the dynamic forces have minor effect on the motion of small sized NMI, making it difficult to penetrate deep into the slag
The Influence of Technological Parameters of X70 Stainless Steel Ladle Refining on the Residual Content of Non-Metallic Inclusions
It is demonstrated that during secondary refining at the ladle furnace the carbon content of steel and the residence time of the metal in the ladle exert a significant impact on the residual content of non-metallic inclusions (NMI) in steel. Mathematical calculations showed that the dynamic forces have minor effect on the motion of small sized NMI, making it difficult to penetrate deep into the slag
Reduced workfunction intermetallic seed layers allow growth of porous n-GaN and low resistivity, ohmic electron transport
Porous GaN crystals have been successfully grown and electrically contacted simultaneously on Pt- and Au-coated silicon substrates as porous crystals and as porous layers. By the direct reaction of metallic Ga and NH3 gas through chemical vapor deposition, intermetallic metal-Ga alloys form at the GaN–metal interface, allowing vapor–solid–solid seeding and subsequent growth of porous GaN. Current–voltage and capacitance–voltage measurements confirm that the intermetallic seed layers prevent interface oxidation and give a high-quality reduced workfunction contact that allows exceptionally low contact resistivities. Additionally, the simultaneous formation of a lower workfunction intermetallic permits ohmic electron transport to n-type GaN grown using high workfunction metals that best catalyze the formation of porous GaN layers and may be employed to seed and ohmically contact a range of III-N compounds and alloys for broadband absorption and emission