Junction Length Research Articles

Comparative study of conventional urosonography without contrast enhancement and x-ray voiding cystourethrography for diagnosis of vesicoureteral reflux in children

Background: Vesicoureteral reflux is the most common urinary congenital anomaly in children. Given the risk associated with radiation exposure there has been an increasing need for radiation-free method in the diagnosis and follow-up of the vesicoureteral reflux. The aim of our study is to compare conventional urosonography without contrast enhancement and x-ray voiding cystourethrography.Patients and Methods: Children with recurrent urinary tract infection with suspected vesicoureteral reflux were included to the study. Vesicoureteral reflux is demonstrated and graded by x-ray voiding cystourethrography. DMSA is used for the evaluation of renal scar. Conventional sonographic procedure was performed in all patients. Ureterovesical junction insertion angle was evaluated. The diameter and length of the ureterovesical junction were also measured.Results: 268 children enrolled to the study. Vesicoureteral reflux was demonstrated in 62 children by x-ray voiding cystourethrography. Ureterovesical junction insertion angle measurement had a statistically significant relation for right and left vesicoureteral reflux presence (right: r: .646, p: .01 and left: r: .446, p: .01). Diagnosis sensitivity of vesicoureteral reflux with conventional ultrasonography is 95.10% and specificity is 81% (Youden’s index 76.1%) for the cutoff value of the ureterovesical junction insertion angle is 28.6 degrees. Positive predictive value is 87.2%, negative predictive value is 94.73% and diagnostic accuracy is 86.29% with conventional ultrasonography.Conclusions: Measurement of ureterovesical junction insertion angle, length and diameter by conventional urosonography is an easy accessible and cheap technique with high sensitivity and specificity for the diagnosis and followup of the vesicoureteral reflux without exposure to ionizing radiation.

Anomalous Josephson effect and quantum anomaly in inversion asymmetric Weyl semimetals

We study a Josephson junction involving an inversion-asymmetric Weyl semimetal in presence of time-reversal symmetric (TRS) or time-reversal symmetry broken tilt in the Weyl spectra. We reveal that both types of tilts in the Weyl nodes lead to a Josephson $0$-$\pi$ transition and a zero bias valley/chiral supercurrent. Strikingly, the TRS tilt gives rise to a pure valley Josephson current (VJC) and TRS broken tilt induces a pure chirality Josephson current (CJC) in this system. The VJC and CJC are the manifestation of valley symmetry broken and $\mathbb{Z}_2$ symmetry broken by the respective tilt. We obtain the reversal of a pure VJC and pure CJC even in the zero bias condition controllable by the junction length. Our analysis of controllability of valley and chirality dependent transport in an inversion asymmetric Weyl semimetal junction could allow applications in valleytronics and chiralitytronics, respectively. The tilt induced Josephson effect provides an alternative route for supercurrent $0$-$\pi$ transition, different from the conventional ferromagnetism Josephson junctions where the spin polarization is essential. In the long junction and zero temperature limit, VJC and CJC are associated with a quantum anomaly which is manifested through a discontinuous jump in the current in absence of TRS and TRS breaking tilts, respectively.

High Performance Gold Dimeric Nanorods for Plasmonic Molecular Sensing

A metal dimeric nanostructure is an alternative design for a Localized Surface Plasmon Resonance sensor. At the dimer nanojunction, a high E-field enhancement (hot spot) is observed. In this work, nanostructure size parameters such as aspect ratio, junction, and length of gold dimeric nanorods (AuDNR) linked end-to-end by a thin dielectric junction were evaluated numerically, optimizing the sensing parameters of the plasmonic nanoplatform. The computational approach focused on the assessment of the LSPR extinction spectral peak shift to their local surrounding medium in order to estimate the behavior of sensing parameters such as the figure of merit (FoM), the bulk sensitivity ( η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> ) and the η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> × FoM. The nanostructure aspect ratio, junction, and rod length were evaluated, optimizing the plasmonic nanoplatforms sensing parameters. The optimized AuDNR achieved a high sensing performance with η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> = 544 nm/RIU and FoM = 12.4 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . Moreover, the obtained η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> × FoM = 6745.6 nm/RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is the highest reported value in the literature. For molecular sensing, Campbell's model was explored to evaluate the wavelength shift as a result of molecular adsorption on the nanoparticle surface. We demonstrate that the dimeric nanostructure exhibit twice LSPR peak shift due to a thin molecular adsorption layer rather than a monomer of equivalent size. Our results show that optimized dimeric nanostructure is highly attractive for molecular identification, opening the possibility of establishing new nanoplatforms for medical diagnostic.

Gate Tunable Supercurrent in Josephson Junctions Based on Bi2Te3 Topological Insulator Thin FilmsSupported by the Basic Science Center Project of the National Natural Science Foundation of China (Grant No. 51788104), and the National Key R&D Program of China (Grant No. 2017YFA0302900).

We report transport measurements on Josephson junctions consisting of Bi2Te3 topological insulator (TI) thin films contacted by superconducting Nb electrodes. For a device with junction length L = 134 nm, the critical supercurrent I c can be modulated by an electrical gate which tunes the carrier type and density of the TI film. I c can reach a minimum when the TI is near the charge neutrality regime with the Fermi energy lying close to the Dirac point of the surface state. In the p-type regime the Josephson current can be well described by a short ballistic junction model. In the n-type regime the junction is ballistic at 0.7 K < T < 3.8 K while for T < 0.7 K the diffusive bulk modes emerge and contribute a larger I c than the ballistic model. We attribute the lack of diffusive bulk modes in the p-type regime to the formation of p–n junctions. Our work provides new clues for search of Majorana zero mode in TI-based superconducting devices.

Role of compensating current in the weak Josephson coupling regime: An extended study on excitonic Josephson junctions

Huang's experiment [Phys. Rev. Lett. $\bf 109$, 156802 (2012)] found, in the quantum Hall bilayer of the Corbino geometry, the interlayer tunneling currents at two edges are coupled to each other and one of two tunneling currents is referred to as the compensating current of the other. Our another work[arXiv:2006.15329] has explained this exotic coupling phenomenon as a result of excitonic Josephson effect induced by interlayer tunneling current. In this paper, we study the same setup -- excitonic Josephson junction -- but in the weak Josephson coupling regime, which occurs for large junction length. Interestingly, we find the compensating current drives the other edge to undergo a nonequilibrium phase transition from a superfluid to resistive state, which is signaled by an abrupt jump of the critical tunneling current. We also identify the critical exponent and furthermore offer more experimental prediction.

Environmental Control of Single-Molecule Junction Evolution and Conductance: A Case Study of Expanded Pyridinium Wiring.

Environmental control of single‐molecule junction evolution and conductance was demonstrated for expanded pyridinium molecules by scanning tunneling microscopy break junction method and interpreted by quantum transport calculations including solvent molecules explicitly. Fully extended and highly conducting molecular junctions prevail in water environment as opposed to short and less conducting junctions formed in non‐solvating mesitylene. A theoretical approach correctly models single‐molecule conductance values considering the experimental junction length. Most pronounced difference in the molecular junction formation and conductance was identified for a molecule with the highest stabilization energy on the gold substrate confirming the importance of molecule–electrode interactions. Presented concept of tuning conductance through molecule–electrode interactions in the solvent‐driven junctions can be used in the development of new molecular electronic devices.

Environmental Control of Single‐Molecule Junction Evolution and Conductance: A Case Study of Expanded Pyridinium Wiring

AbstractEnvironmental control of single‐molecule junction evolution and conductance was demonstrated for expanded pyridinium molecules by scanning tunneling microscopy break junction method and interpreted by quantum transport calculations including solvent molecules explicitly. Fully extended and highly conducting molecular junctions prevail in water environment as opposed to short and less conducting junctions formed in non‐solvating mesitylene. A theoretical approach correctly models single‐molecule conductance values considering the experimental junction length. Most pronounced difference in the molecular junction formation and conductance was identified for a molecule with the highest stabilization energy on the gold substrate confirming the importance of molecule–electrode interactions. Presented concept of tuning conductance through molecule–electrode interactions in the solvent‐driven junctions can be used in the development of new molecular electronic devices.

Alignment free identification of clones in B cell receptor repertoires.

Following antigenic challenge, activated B cells rapidly expand and undergo somatic hypermutation, yielding groups of clonally related B cells with diversified immunoglobulin receptors. Inference of clonal relationships based on the receptor sequence is an essential step in many adaptive immune receptor repertoire sequencing studies. These relationships are typically identified by a multi-step process that involves: (i) grouping sequences based on shared V and J gene assignments, and junction lengths and (ii) clustering these sequences using a junction-based distance. However, this approach is sensitive to the initial gene assignments, which are error-prone, and fails to identify clonal relatives whose junction length has changed through accumulation of indels. Through defining a translation-invariant feature space in which we cluster the sequences, we develop an alignment free clonal identification method that does not require gene assignments and is not restricted to a fixed junction length. This alignment free approach has higher sensitivity compared to a typical junction-based distance method without loss of specificity and PPV. While the alignment free procedure identifies clones that are broadly consistent with the junction-based distance method, it also identifies clones with characteristics (multiple V or J gene assignments or junction lengths) that are not detectable with the junction-based distance method.

Physiological and morphological correlates of extreme acid tolerance in larvae of the acidophilic amphibian Litoria cooloolensis.

The Cooloola sedgefrog (Litoria cooloolensis) is one of a number of frog species endemic to the coastal sandy lowlands of east Australia exhibiting remarkable tolerance to dilute waters of low pH (<pH 3.5). To investigate the physiological and morphological underpinnings of acid tolerance in L. cooloolensis larvae, we compared Na+ balance, uptake and efflux rates, and gill and skin morphology in larvae reared in circum-neutral (pH 6.5) and pH 3.5 water. We hypothesised that L. cooloolensis larvae would be more resistant to ionregulatory disturbance and epithelial damage at low pH relative to acid-sensitive species. Net Na+ flux rates were not significantly different from zero in L. cooloolensis larvae reared at pH 3.5 and in acid-naïve animals maintained in pH 6.5 water. Animals reared at pH 6.5 and acutely exposed to pH 3.5, however, exhibited a net loss of Na+ due to inhibition of Na+ uptake. In contrast, L. cooloolensis larvae reared at pH 3.5 maintained Na+ balance at pH 3.5 and did not exhibit inhibition of Na+ uptake at this pH. Investigation of Na+ transport kinetics and the morphology of the gills and integument suggests tolerance of L. cooloolensis larvae to low pH may be attributed to a high capacity for branchial Na+ uptake, increased tight junction length and elevated mucus production at the gills and integument. These factors confer resistance to acid damage and disruption of ionic homeostasis which would otherwise result in the death of amphibian larvae exposed to waters of pH 4.0 and less.

The structural characteristics of photoaging in mice caused by the effects of ultraviolet A radiation.

Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoaging. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoaging in mice exposed to UVA radiation, with or without the application of a photoprotective cream. The experiment consisted of the radiation of female BALBc mice in a solarium by UVA rays, up to total dosages of 7800 J/cm² and 12500J/cm². A total of 78 animals were divided into 4 experimental and 2 control groups. All animals were shaved and the animals in 2 experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with Hematoxylin-eosin and Van-Gieson staining methods. All measurements, except for the presence of dyskeratosis, were taken using ImageJ 150i software. In the study, the signs of skin photoaging were more evident in untreated groups of animals. Dysceratosis was more frequent in both of the untreated groups of animals (p=0.004) and (p=0.003). The lowest values of epidermal thickness (13.8± 2.6μm and 12.7±2.3μm) were present in both of the untreated groups of animals (p<0.001) and (p<0.001). The highest values of stratum corneum thickness (34.3±8.5μm) were observed in the untreated, shorter radiated group of animals (p<0.001) which was irradiated for the shortest period of time. Beside the control groups, the highest length of dermo-epidermal junction (DEJ) was recorded in the group of treated, longer radiated animals (1467.6±94.6μm) (p=0.373). The lowest values of dermal thickness (115.9±10.5μm and 134.8±21.8μm) and volumetric density of the collagen fibers (31.92±3.19% and 29.40±4.54%) were present in both untreated groups of animals (p<0.001), (p<0.001), (p=0.035). Skin photoaging was most pronounced in the groups of animals irradiated without the application of photoprotective cream.

Josephson effect in type-I Weyl semimetals

The emergent Weyl fermions in condensed matter generally break the Lorentz invariance resulting in a tilted (type-I) or over-tilted (type-II) energy dispersion. The tilting energy spectrums can lead to exotic quantum interference effects in a junction set up. Here, we theoretically investigate the Josephson current in a Weyl superconductor-Weyl (semi)metal-Weyl superconductor junction of a time-reversal (TR) broken type-I Weyl semimetal. We demonstrate that the Cooper pairs of BCS-like pairing acquire a finite momentum in case of inversion symmetric tilt. Consequently, the system exhibits tilt induced anomalous current phase relations which are manifested by supercurrent $0$-$\pi$ transition and Josephson $\phi$ junction. On the contrary, these effects remain absent in case of inversion breaking tilt and for FFLO-like pairing in the Weyl superconductor. We further chart out qualitative differences between the two distinct types of pairings by studying the critical current dependency on junction length. Our study opens a new avenue to probe the unconventional superconducting pairings in TR-broken Weyl semimetals. It is also quite interesting that the tilting in Weyl nodes naturally leads to anomalous current phase relations in this model without any magnetic manipulation!

Analytical Modelling and Simulation of Si-Ge Hetero-Junction Dual Material Gate Vertical T-Shaped Tunnel FET

In this paper, a compact 2D analytical modelling of surface potential and simulation of Si-Ge hetero-junction Dual Material Gate Vertical t-shape T-FET is presented. In the proposed model, device is divided into two gate-metal work function named as tunneling gate and auxiliary gate. Both the biasing voltage of source and drain will have controlled effect on the device’s surface potential which are used to access the depletion length of the tunneling junction. Therefore, the tunneling current will use the surface potential model as basic principle to drive the current model of the device. For solving the 2D Poisson equation with the necessary boundary conditions, parabolic approximation methods are employed. We test the reliability of surface potential on different parameters profile by varying it as a function of Si-Ge material mole-fraction, gate-source voltage, drain-source voltage, gate-oxide thickness, high k dielectric constant and different gate work function and various compound material used. Finally, we come out with the expression of the channel surface potential that will change in accordance with the drain and gate biasing voltage. The validity of the projected model has been confirm by showing agreement between the analytical findings and TCAD simulation results.

Array Synthesis Horn Antenna with an Extended Horn and a Stepped Corrugated Structure for High-Power Microwave Applications

This study proposes an array synthesis horn antenna with an extended horn and a stepped corrugated structure for a high-power microwave system. The horn antenna is designed by joining four pyramidal horn antennas and an extended horn to obtain a high gain. To improve the beam pattern in the H-plane, the length of the vertical junction of the pyramidal horns is controlled. Two-stepped and partitioned corrugated structures are attached to both horizontal edges of the aperture for a good front-to-back ratio. The designed 2 × 2 array synthesis horn antenna has a gain of 19.7 dBi and front-to-back ratio of 39.6 dB in the measurement.

Tunable nonlocal valley-entangled Cooper pair splitter realized in bilayer-graphene van der Waals spin valves

We investigate the Cooper pair splitting based on crossed Andreev reflection in a two-dimensional narrow superconductor coupled to two leads, where the two leads are van der Waals (vdW) spin valves formed by inserting bilayer graphene (BLG) between two antiparallel insulating ferromagnetic layers. In this BLG-based $n$-type vdW spin valve/superconductor/$p$-type vdW spin valve junction with edge-contact geometry, when controlling the Fermi energy and the interlayer electric field in BLG independently by top- and bottom-gate voltages in the vdW spin valve region, we first demonstrate that the two electrons of perfect Cooper pair splitting can remain nonlocal valley entanglement. This effect can be explained as follows: When both the two antiparallel insulating ferromagnetic layers and the interlayer electric field are taken into account, BLG exhibits a spin-splitting but valley-degenerate band gap near the Dirac point. Thus, our setups allow the Cooper pair in the BCS scenario to serve as a natural source of valley entanglement. We further predict large oscillations of cross conductance as a function of the doping of the superconductor, the junction length, and the bias voltage. Our results may provide a tool for realizing fast nonlocal switching of the valley-entanglement state.

Ultrasound Measurements of the ECRB Tendon Shows Remarkable Variations in Patients with Lateral Epicondylitis.

Lateral epicondylitis (LE) most commonly affects the Extensor Carpi Radialis Brevis (ECRB) tendon and patients are generally treated with injection therapy. For optimal positioning of the injection, as well as an estimation of the surface area and content of the ECRB tendon to determine the volume of the injectable needed, it is important to know the exact location of the ECRB in relation to the skin as well as the variation in tendon length and location. The aim of this study was to determine the variation in location and size of the ECRB tendon in patients with LE. An observational sonographic evaluation of the ECRB tendon was performed in 40 patients with LE. The length of the ECRB tendon, distance from the cutis to the center of the ECRB tendon, the length of the osteotendinous junction at the epicondyle and the distance from cutis to middle of the osteotendinous junction were measured. The average tendon length was 1.68cm (range 1.27-1.98; SD 0.177). Compared to women, the ECRB tendon of men was on average 0.12cm longer. Overall, the average distance from cutis to the center of the ECRB was 0.75cm (range 0.50-1.46cm; SD 0.210), the average length of the junction was 0.55cm (range 0.35-0.87; SD 0.130), and the distance from cutis to middle of the osteotendinous junction was 0.73cm (range 0.40-1.25cm; SD 0.210). The size and depth of the ECRB tendon in patients with LE is largely variable. While there are no studies yet suggesting sono-guided injection to be superior to that of blind injection, the anatomic variability of this study suggests that the accuracy of injection therapy for LE might be compromised when based solely on bony landmarks and therefore not fully reliable. As a result, there is value in further studies exploring the accuracy of the ultrasound guided injection techniques.

RhoA Mediates Epithelial Cell Shape Changes via Mechanosensitive Endocytosis.

Epithelial remodeling involves ratcheting behavior whereby periodic contractility produces transient changes in cell-cell contact lengths, which stabilize to produce lasting morphogenetic changes. Pulsatile RhoA activity is thought to underlie morphogenetic ratchets, but how RhoA governs transient changes in junction length, and how these changes are rectified to produce irreversible deformation, remains poorly understood. Here, we use optogenetics to characterize responses to pulsatile RhoA in model epithelium. Short RhoA pulses drive reversible junction contractions, while longer pulses produce irreversible junction length changes that saturate with prolonged pulse durations. Using an enhanced vertex model, we show this is explained by two effects: thresholded tension remodeling and continuous strain relaxation. Our model predicts that structuring RhoA into multiple pulses overcomes the saturation of contractility and confirms this experimentally. Junction remodeling also requires formin-mediated E-cadherin clustering and dynamin-dependent endocytosis. Thus, irreversible junction deformations are regulated by RhoA-mediated contractility, membrane trafficking, and adhesion receptor remodeling.

Mathematical model of adhesion junction of layers during coextrusion

Nine theories of polymer adhesion during coextrusion are researched. Two approaches to describing adhesion are presented – thermodynamic and molecular-kinetic ones. The factors, determining the durability of adhesion junction, are analyzed. The stages of adhesion connection formation are presented. The adhesion junction emergence model as a result of intermolecular interaction is described. As a result of calculations the following dependencies are got: the dependence of ply separation energy on the contact length of polyisobutylene adhesion junction of different molecular weight, the dependence of ply separation energy on molecular weight of polyisobutylene adhesion junctions got during different time, the dependence of adhesion durability on squared difference of polymer solubility parameters, the dependence of interdiffused zone width in the time.

Faster growth corresponds with shallower linear hypoplastic defects in great ape canines

Deeper or more ‘severe’ linear enamel hypoplasia (LEH) defects are hypothesized to reflect more severe stress during development, but it is not yet clear how depth is influenced by intrinsic enamel growth patterns. Recent work documented inter- and intraspecific differences in LEH defect depth in extant great apes, with mountain gorillas having shallower defects than other taxa, and females having deeper defects than males. Here, we assess the correspondence of inter- and intraspecific defect depth and intrinsic aspects of enamel growth: enamel extension rates, outer enamel striae of Retzius angles, and linear enamel thickness. Thin sections of great ape canines (n = 40) from Gorilla beringei beringei, Gorilla gorilla gorilla, Pan troglodytes, and Pongo spp. were analyzed. Enamel extension rates were calculated within deciles of enamel-dentine junction length. Linear enamel thickness and the angle of intersection between striae of Retzius and the outer enamel surface were measured in the imbricational enamel. Mountain gorillas have faster enamel extension rates and shallower striae angles than the other taxa examined. Mountain gorillas have thinner imbricational enamel than western lowland gorillas and orangutans, but not chimpanzees. In the combined-taxon sample, females exhibit larger striae angles and thicker imbricational enamel than males. Enamel extension rates are highly negatively correlated with striae angles and LEH defect depth. Enamel growth variation corresponds with documented inter- and intraspecific differences in LEH defect depth in great ape canines. Mountain gorillas have shallower striae angles and faster extension rates than other taxa, which might explain their shallow LEH defect morphology and the underestimation of their LEH prevalence in previous studies. These results suggest that stressors of similar magnitude and timing might produce defects of different depths in one species or sex vs. another, which has implications for interpretations of stress histories in hominins with variable enamel growth patterns.

Mechanosensitive Junction Remodeling Promotes Robust Epithelial Morphogenesis

Morphogenesis of epithelial tissues requires tight spatiotemporal coordination of cell shape changes. In vivo, many tissue-scale shape changes are driven by pulsatile contractions of intercellular junctions, which are rectified to produce irreversible deformations. The functional role of this pulsatory ratchet and its mechanistic basis remain unknown. Here we combine theory and biophysical experiments to show that mechanosensitive tension remodeling of epithelial cell junctions promotes robust epithelial shape changes via ratcheting. Using optogenetic control of actomyosin contractility, we find that epithelial junctions show elastic behavior under low contractile stress, returning to their original lengths after contraction, but undergo irreversible deformation under higher magnitudes of contractile stress. Existing vertex-based models for the epithelium are unable to capture these results, with cell junctions displaying purely elastic or fluid-like behaviors, depending on the choice of model parameters. To describe the experimental results, we propose a modified vertex model with two essential ingredients for junction mechanics: thresholded tension remodeling and continuous strain relaxation. First, junctions must overcome a critical strain threshold to trigger tension remodeling, resulting in irreversible junction length changes. Second, there is a continuous relaxation of junctional strain that removes mechanical memory from the system. This enables pulsatile contractions to further remodel cell shape via mechanical ratcheting. Taken together, the combination of mechanosensitive tension remodeling and junctional strain relaxation provides a robust mechanism for large-scale morphogenesis.

Illumination study of a quantum MIM diode for the mid-infrared

Metal-insulator-metal (MIM) junctions with insulators a few nanometers thick are quantum-tunneling diodes able to operate at frequencies up to Hz. However, their main limitation is their poor harvested current. This paper demonstrates that a distributed illumination produced by combining a beam splitter with the Kretschmann and Reather prism-based configuration extends the tunneling event to the entire junction length with the same probability all along the junction. This increases the harvested quantum-tunneling current and the diode responsivity.