Reverse Branch Research Articles

Pro mekhanizm vplyvu hazovoho seredovyshcha na elektrofizychni parametry heterostruktur na osnovi bar"yera Shottki z nanostrukturovanymy plivkamy skladu (95% In2O3 + 5% SnO2)

Electrophysical characteristics of gas-sensitive Ni – (95% In2O3 + 5% SnO2) – p-Si heterojunctions have been studied experimentally. The analysis of their current-voltage characteristics (CVCs) registered in various gas environments reveals a significant increase of the reverse current through specimens in the atmosphere of ethanol or isopropyl vapor. Various mechanisms of current flow through the heterojunction are considered to explain this phenomenon. Variations in the potential barrier height under the action of image forces are demonstrated to play a significant role in shifts of the reverse CVC branches of examined specimens. The image force changes are explained by the influence of the adsorbate on the dielectric permittivity of oxide films.

The Application of Reverse-Time Migration in the Z Area of PRM Basin

Reverse time migration (RTM) is an accurate migration method, which is based on two-way wave equation, eliminates angle limitation, and can be capable for imaging of reverse branch and multiple. In the development of an oilfield in Pearl River Mouth (PRM) Basin, RTM has been applied to solve the problems of fault shadow and structure in distinction and the drilling has proven that the RTM result is reliable. This paper introduces the theory of RTM and emphatically discusses parameter selection. The results of RTM showed that it had advantages in resolving fault shadow and the imaging of steep dip structure, and could be utilized in the oilfield.

Preisach modelling of lithium-iron-phosphate battery hysteresis

The hysteresis of the open-circuit voltage as a function of the state-of-charge in a 20Ah lithium-iron-phosphate battery is investigated starting from pulsed-current experiments at a fixed temperature and ageing state, in order to derive a model that may reproduce well the battery behaviour. The hysteretic behaviour is modelled with the classical Preisach model used in magnetic materials. The paper shows that the Preisach model can successfully be applied to the lithium-ion battery hysteresis. First, the model is discretised by using the Everett function and identified by means of experiments, in which first-order reversal branches are measured. Then, the model is simulated and compared to some experimental data collected with different current profiles and to a one-state variable model previously used in the literature. The results show that the hysteresis is well reproduced with rms errors around 2%. The advantages of the Preisach-based method, when compared to other models, are the formal and repeatable identification procedure and the limited computational resources needed for the model simulation that makes it appropriate for the online implementation on low-complexity hardware platforms.

Execution of energy efficient detection of hydrogen using Pt/WO x /SiC semiconductor structure

It has been shown that, at elevated temperatures (∼350°C), the most distinct response to H2 from the thin film structure Pt/WO x /SiC is achieved at registration of change in voltage for the reverse branch of a current-voltage characteristic. Comparative studies of electric current conduction through the structure and over its surface (with deposited Pt film) have led to the conclusion that a change in properties of the Pt/WO x and WO x /SiC interfaces under action of H2 mostly determines efficiency of response of the structure in the case of “transverse” measuring geometry. In the case of a 2% concentration of H2 in air the voltage shift for the reverse branch at a current of ∼10 μA reached 5 V against 2 V on the forward branch and “planar” geometry of measurements.

Structure and morphology of nanoporous zno and dark current‐Voltage characteristics of the glass/(TCO)/zno/poly[2,7‐(9,9‐dioctylfluorene)‐alt‐(5,5'‐bithiophene)/ag structure

ABSTRACTThe hybrid organic‐inorganic structure based on glass/(TCO)/nanoporous ZnO/poly[2,7‐(9,9‐dioctylfluorene)‐alt‐(5,5′‐bithiophene)]/Ag that was prepared by physical deposition has been investigated. The structure of the nanostructured ZnO obtained by magnetron sputtering was confirmed by X‐ray diffractometry (XRD) and energy dispersive X‐ray spectroscopy (EDX). Scanning electron microscopy (SEM) analysis proved the existence of short and interconnected zinc oxide (ZnO) fibers, which form a continuous porous network with pores having an average diameter of 100 nm. Current‐voltage (I‐V) curves of the glass/TCO/ZnO/PF‐BT/Ag hybrid structure are similar to those of typical p‐n junctions and stable until 90°C temperature. According to the I‐V characteristics, the dominant mechanism of current flow is based on the generation‐recombination of carriers in the depletion region at low direct biases and also on the injection of carriers at high biases. The reverse branch of the I‐V characteristic, calculated in log‐log scale, shows one segment with a power coefficient of 3/2 at room temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42415.

In vitro expansion of U87-MG human glioblastoma cells under hypoxic conditions affects glucose metabolism and subsequent in vivo growth.

Hypoxia is a characteristic feature of solid tumors leading to the over expression of hypoxia-inducible factor (HIF)-1α protein and therefore to a specific cellular behavior. However, even though the oxygen tension in tumors is low (<5 %), most of the cell lines used in cancer studies are grown under 21 % oxygen tension. This work focuses on the impact of oxygen conditions during in vitro cell culture on glucose metabolism using 1-(13)C-glucose. Growing U87-MG glioma cells under hypoxic conditions leads to a two- to threefold reduction of labeled glutamine and an accumulation of fructose. However, under both hypoxic and normoxic conditions, glucose is used for de novo synthesis of pyrimidine since the (13)C label is found both in the uracil and ribose moieties. Labeling of the ribose ring demonstrates that U87-MG glioma cells use the reversible branch of the non-oxidative pentose phosphate pathway. Interestingly, stereotactic implantation of U87-MG cells grown under normoxia or mild hypoxia within the striatum of nude mice led to differential growth; the cells grown under hypoxia retaining an imprint of the oxygen adaptation as their development is then slowed down.

Molecular Logic Computation with Debugging Method

Seesaw gate concept, which is based on a reversible DNA strand branch process, has been found to have the potential to be used in the construction of various computing devices. In this study, we consider constructing full adder and serial binary adder, using the new concept of seesaw gate. Our simulation of the full adder preformed properly as designed; however unexpected exception is noted in the simulation of the serial binary adder. To identify and address the exception, we propose a new method for debugging the molecular circuit. The main idea for this method is to add fan‐outs to monitor the circuit in a reverse stepwise manner. These fan‐outs are fluorescent signals that can obtain the real‐time concentration of the target molecule. By analyzing the monitoring result, the exception can be identified and located. In this paper, examples of XOR and serial binary adder circuits are described to prove the practicability and validity of the molecular circuit debugging method.

Evolution of Structure and Electrical Characteristics of Pt/WOx/6H-SiC Sensor Upon Exposure to H2 Gas at High Temperature

The bilayer film Pt/WOx was deposited by pulsed laser ablation on a silicon carbide monocrystal plate (6H-SiC) to form an H2 sensor for high temperature application. The study demonstrates high sensitivity of the Pt/WOx/SiC structure to a low H2 concentration. For 0.2 H2% in air at 350°C, the shift of voltage on the reverse branch of the current-voltage characteristic reached 6.5V at a current of 0.4μA. After the high temperature interaction with H2, the sample can confine hydrogen atoms in the WOх layer at room temperature for a long time. The study explores the influence of operation conditions as well as the H2 action on the structure and electrical characteristics of the layers in the system. Phase transformation of the crystalline structure of the WOx film due to hydrogen penetration was detected and this process initiated pronounced electrical properties changes.

Device for rejection of semiconductor diodes

The article describes the control device, allowing to make rejection of semiconductor diodes. The proposed device has a high accuracy and reliability of the control. The device allows you to set different rates of change of the out-put voltage of the sawtooth generator. Quality control is performed by diode reverse branch of the current-voltage characteristics. The device provides a better signal / noise ratio at low current levels.

Specific features of electroluminescence in heterostructures with InSb quantum dots in an InAs matrix

The electrical and electroluminescence properties of a single narrow-gap heterostructure based on a p-n junction in indium arsenide, containing a single layer of InSb quantum dots in the InAs matrix, are studied. The presence of quantum dots has a significant effect on the shape of the reverse branch of the current-voltage characteristic of the heterostructure. Under reverse bias, the room-temperature electroluminescence spectra of the heterostructure with quantum dots, in addition to a negative-luminescence band with a maximum at the wavelength λ = 3.5 μm, contained a positive-luminescence emission band at 3.8 μm, caused by radiative transitions involving localized states of quantum dots at the type-II InSb/InAs heterointerface.

Dauer-Specific Dendrite Arborization in C. elegans Is Regulated by KPC-1/Furin

Dendrites often display remarkably complex and diverse morphologies that are influenced by developmental and environmental cues. Neuroplasticity in response to adverse environmental conditions entails both hypertrophy and resorption of dendrites. How dendrites rapidly alter morphology in response to unfavorable environmental conditions is unclear. The nematode Caenorhabditis elegans enters into a stress-resistant dauer larval stage in response to an adverse environment. Here we show that the IL2 bipolar sensory neurons undergo dendrite arborization and axon remodeling during dauer development. When dauer larvae are returned to favorable environmental conditions, animals resume reproductive development and IL2 dendritic branches retract, leaving behind remnant branches in postdauer L4 and adult animals. The C. elegans furin homolog KPC-1 is required for dauer IL2 dendritic arborization and dauer-specific nictation behavior. KPC-1 is also necessary for dendritic arborization of PVD and FLP sensory neurons. In mammals, furin is essential, ubiquitously expressed, and associated with numerous pathologies, including neurodegenerative diseases. While broadly expressed in C. elegans neurons and epithelia, KPC-1 acts cell autonomously in IL2 neurons to regulate dauer-specific dendritic arborization and nictation. Neuroplasticity of the C. elegans IL2 sensory neurons provides a paradigm to study stress-induced and reversible dendritic branching, and the role of environmental and developmental cues in this process. The newly discovered role of KPC-1 in dendrite morphogenesis provides insight into the function of proprotein convertases in nervous system development.

Kinetic Analysis of DNA Strand Joining by Chlorella Virus DNA Ligase and the Role of Nucleotidyltransferase Motif VI in Ligase Adenylylation

Chlorella virus DNA ligase (ChVLig) is an instructive model for mechanistic studies of the ATP-dependent DNA ligase family. ChVLig seals 3'-OH and 5'-PO(4) termini via three chemical steps: 1) ligase attacks the ATP α phosphorus to release PP(i) and form a covalent ligase-adenylate intermediate; 2) AMP is transferred to the nick 5'-phosphate to form DNA-adenylate; 3) the 3'-OH of the nick attacks DNA-adenylate to join the polynucleotides and release AMP. Each chemical step requires Mg(2+). Kinetic analysis of nick sealing by ChVLig-AMP revealed that the rate constant for phosphodiester synthesis (k(step3) = 25 s(-1)) exceeds that for DNA adenylylation (k(step2) = 2.4 s(-1)) and that Mg(2+) binds with similar affinity during step 2 (K(d) = 0.77 mM) and step 3 (K(d) = 0.87 mM). The rates of DNA adenylylation and phosphodiester synthesis respond differently to pH, such that step 3 becomes rate-limiting at pH ≤ 6.5. The pH profiles suggest involvement of one and two protonation-sensitive functional groups in catalysis of steps 2 and 3, respectively. We suggest that the 5'-phosphate of the nick is the relevant protonation-sensitive moiety and that a dianionic 5'-phosphate is necessary for productive step 2 catalysis. Motif VI, located at the C terminus of the OB-fold domain of ChVLig, is a conserved feature of ATP-dependent DNA ligases and GTP-dependent mRNA capping enzymes. Presteady state and burst kinetic analysis of the effects of deletion and missense mutations highlight the catalytic contributions of ChVLig motif VI, especially the Asp-297 carboxylate, exclusively during the ligase adenylylation step.

Kinetic Schemes for Post-Synchronized Single Molecule Dynamics

Recordings from single molecule experiments can be aggregated to determine average kinetic properties of the system under observation. The kinetics after a synchronized reaction step can be interpreted using all of the standard tools developed for ensemble perturbation experiments. The kinetics leading up to a synchronized event, determined by the lifetimes of the preceding states; however, are not as obvious if the reaction has reversible steps or branches. Here we describe a general procedure for dealing with these situations.

Demonstration of reversible complete left bundle branch block following tachycardia-induced cardiomyopathy

A 56-year-old man with atrial fibrillation and complete left bundle branch block (CLBBB) developed heart failure refractory to the initial medical treatment. Both the CLBBB and cardiac dysfunction completely recovered only with an advanced medical regimen for rate control and heart failure. This report describes a case with reversible CLBBB following tachycardia-induced cardiomyopathy, who was not a candidate for cardiac resynchronization therapy.

Reversible branch retinal artery occlusion following intravenous cisplatin chemotherapy for cervical carcinoma

Cisplatin (CDDP) is a chemotherapeutic agent widely used to treat solid tumours. We present a case of reversible CDDP-associated branch retinal artery occlusion.

Repair of the soft tissue defects at legs with free tissue flap anastomosed with descendant branch of lateral femoral circumflex artery

To investigate the therapeutic effect of free tissue flap anastomosed with reverse descendant branch of lateral femoral circumflex artery for severe soft tissue defect at leg. The severe soft tissue defect at leg, without any vessels for anastomosis of free tissue flap, was reconstructed with free tissue flap, which was anastomosed with proximal end of descendant branch of lateral femoral circumflex artery and great saphenous vein. From Oct. 2004 to Dec. 2009, 36 cases were treated with 15 cases of latissimus dorsi musculocutaneous flaps, 12 cases of anterolateral femoral flaps, and 9 cases of thoracoumbilicus flaps. All the 36 free flaps survived completely. The patients were followed up for 6 months to 2.5 years with good cosmetic results. It is effective and practical to repair the severe soft tissue defects at legs with the reverse descendant branch of lateral femoral circumflex artery to carry the free flaps.

Anodic dissolution and passivation of lead in sodium sulfate solutions

The anodic behavior of lead depending on the sulfate solution concentration is studied. The relation between oxide-hydroxide passivation and salt repassivation is found. The main characteristics of the forward and reverse branches of the polarization curves and cyclic voltammograms, as well as anodic chronoammograms and cathodic chronopotentiograms, are determined. The time dependence of the phase-formation current is constructed and analyzed.

Conductivity of semiconductor diodes with simultaneously applied direct and alternating biases

The influence of a high-amplitude high-frequency signal on the static current-voltage characteristics of commercial semiconductor p-n junction diodes is studied experimentally. S-shaped regions are observed in the direct branches of the current-voltage characteristics over a wide frequency range, and a bell-shaped segment is seen in the reverse branches. The value and position of the latter on the voltage axis considerably depend on the alternating signal frequency.

NEW POSSIBILITIES FOR OBTAINING STEEPLY NONLINEAR CURRENT–VOLTAGE CHARACTERISTICS IN SOME SEMICONDUCTOR STRUCTURES

Electronic processes in a semiconductor system consisting of some resonant tunneling structures, built in the depletion region of a Schottky barrier, are investigated. It is shown that the Schottky barrier can block or unblock the resonant tunneling current effectively. Tunneling processes do reveal the coherent character. Sharply nonlinear current–voltage characteristics are observed for both the forward and the reverse branches.

High-resolution spatial rupture pattern of a multiphase flower structure, Rex Hills, Nevada: New insights on scarp evolution in complex topography based on 3-D laser scanning

Fault scarps represent the most obvious expression of tectonic activity at the Earth9s surface. Studies on scarp morphology place constraints on fault kinematics and scarp-degradation processes, and were often based on geomorphic dating techniques. Fault scarps exposed in areas of simple topography facilitate data acquisition and interpretation, whereas little work had been done where fault scarps are superimposed on complex, dissected topography. Fault scarps developed in complex topography are commonly observed along flower structures and at tips of strike-slip faults. Such structures are important elements for evaluating the evolution and linking of strike-slip fault systems, and appear to be scale-independent from several meters to hundreds of kilometers. We examined the detailed meter- to hundred meter–scale structure and surface expression of a flank of one fault scarp–bounded pressure ridge (Rex Hills flower structure) by combining field mapping with high-resolution digital elevation model (DEM) analysis. Based on terrestrial laser scanning we generated a detailed DEM and extracted high-resolution topographic cross sections, which enabled us to identify fault scarps and to determine their relative ages and geometry. Our study site is located on the transpressional left-bend between the Pahrump and Amargosa segments of the dextral Stateline fault system. The topography is characterized by alternating valleys and ridges (each ∼100 m long, relief of ∼4 m). We observed the following: the southern Rex Hills slope exhibits three fault scarps related to three reverse fault branches; the basal scarp (scarp 1) is most continuous, and exhibits five segments, the upper two scarps (scarps 2 and 3) are less continuous. Furthermore, fault scarps exposed on ridge crests are more numerous (up to four to five scarps), and smaller (∼5 m high); valleys often exhibit single large (>10 m high), smoothed scarps. To easily detect differences between the scarps, we evaluated the height and slope angle of the scarps using topographic cross sections. Our analysis indicates that scarp shape is influenced by fault dip, lithology, and degradation processes resulting in large scatter and broad overlap in scarp-height–slope-angle space. The analysis further indicates that scarp degradation is stronger in the valleys, and that the preservation potential of small, individual fault scarps is therefore greater on the ridge crests. We compared our fault-scarp data with published, calibrated data yielding an age of ∼2 ka for the Rex Hills scarps consistent with an earlier finding. This suggests that the scarp shape mainly reflects progressive degradation since the most recent surface rupture. Our approach of analyzing high-resolution topographic data of closely spaced fault scarps is promising especially when combined with subsurface data as well as geochronological and paleoseismic data, and it provides a basic scheme for analyzing scarp populations in a complex topographic region. Despite the absence of subsurface data, our approach allowed the study of complex high-resolution fault-scarp morphologies across a flower structure for the first time.