Junction Length Research Articles

Prevalence, risk factors and genetic parameters of cresty neck in Pura Raza Español horses.

Cresty neck is a relatively common morphological defect in Pura Raza Español horses and other Baroque type horse breeds, which adversely affects the breeding industry. To establish the within-breed prevalence, possible associated factors and heritability of cresty neck in Pura Raza Español horses. Cross-sectional analysis of a large worldwide database of Pura Raza Español horses. The database included evaluations of 10,929 Pura Raza Español horses from 24 countries. Cresty neck score, on a 9 point scale, girth-to-height ratio, height at the withers, length of neck, head-neck junction and neck-body junction were recorded. A Bayesian genetic animal model included the following systematic effects: girth-to-height ratio, age, sex, coat colour and geographical area of the stud. Animal and residual effects were included as random effects. Within this Pura Raza Español population, 8.91% had a cresty neck score ≥5, which is the threshold for penalty or disqualification in the studbook of the breed. The age, sex, coat colour and stud geographical area were significantly associated with cresty neck score. The estimated heritability coefficient for cresty neck score was 0.37 (s.d. = 0.034) and genetic correlation between cresty neck score and other conformational traits ranged from -0.06 (height-at-withers) to -0.21 (neck-body junction). Cresty neck is a prevalent defect in Pura Raza Español horses, associated with age, sex, coat colour and other conformational traits, with a moderate level of heritability. Breeding to select against this condition may therefore be beneficial in this breed.

Transport properties of spin-triplet superconducting monolayerMoS2

The quantum transport properties of graphene and monolayer $MoS_2$ superconductor heterostructures has been of considerable importance in the recent few years. Layered nature of molybdenum disulfide permits the superconducting correlation induction. Moreover, peculiar dynamical features of monolayer $MoS_2$, such as valence band spin-splitting in the nondegenerate $K$ and $K'$ valleys originated from strong spin-orbit coupling, and considerable direct band gap can make it potentially a useful material for electronics applications. Using the Dirac-like Hamiltonian of $MoS_2$ with taking into account the related mass asymmetry and topological contributions, we investigate the effect of spin-triplet $p$-wave pairing symmetry on the superconducting excitations, resulting in Andreev reflection process and Andreev bound state in the corresponding normal-superconductor (NS) and superconductor-normal-superconductor (SNS) structures, respectively. We study how the resulting subgap conductance and Josephson current are affected by the particular symmetry of order parameter. The signature of $p_x$-wave symmetry is found to decline the subgap superconducting energy excitations and, consequently, slightly suppress the Andreev reflection in the case of $p$-doped S region. The essential dynamical parameters $\lambda$ and $\beta$ of $MoS_2$ have significant effect on the both tunneling conductance and Josephson current. Particularly, the considered $p$-wave symmetry in the superconducting bound energies may feature the zero energy states at the interfaces. The critical current oscillations as a function of length of junction are obtained in the $p$-doped S region.

Abstract 16420: The E3 Ubiquitin Ligase is Upregulated During Cardiac Hypertrophy

Introduction: Cardiomyocyte hypertrophy is observed during normal postnatal cardiac development as well as during disease-related cardiac remodeling. This growth is accompanied by dynamic changes at the intercalated disc, including the redistribution and degradation of the gap junction protein connexin 43 (Cx43). We have shown that the ubiquitin ligase Wwp1 can promote the degradation of Cx43, and that genetic upregulation of Wwp1 stimulates hypertrophy and arrhythmogenesis. Hypothesis: We hypothesized that changes in the expression of Wwp1 would be associated with developmental and pathological hypertrophy programs. Methods: Expression of Wwp1 was analyzed by digital droplet PCR in hearts derived from normally developing mice at 2, 4, 6, and 8 weeks of age (n=6 for each) or from adult mice subjected to transverse aortic constriction (n=5) vs. sham operated animals (n=5). Cardiac structure and function of mice overexpressing or lacking expression of Wwp1 was evaluated by transmission electron microscopy (n=3) and echocardiography (n=6). Results: The expression of Wwp1 during postnatal development was very dynamic, peaking at a concentration of 324 copies/uL in the hearts derived from 4 week old animals. This also corresponded to the timepoint when the gap junction length at the intercalated disc plateaued. Further, a 1.5-fold increase in the expression of Wwp1 in animals subjected to pressure overload was detected as compared to animals subjected to surgery without pressure overload (p<0.007). Interestingly, the concentration of Wwp1 message in pressure overloaded animals (331 copies/uL) was nearly identical to that found in 4 week old wild type animals during normal postnatal development. Consistent with the level of Wwp1 correlating with cardiomyocyte hypertrophy, animals lacking Wwp1 had a 23-42% decrease in left ventricular mass (p<0.01) whereas transgenic animals overexpressing Wwp1 had a 28-50% increase in left ventricular mass (p<0.005) as compared to wild type controls between 4 and 8 weeks of age. Conclusions: This study shows that expression of Wwp1 is upregulated during hypertrophy and this correlates with ultrastructural changes at the intercalated disc.

Shot noise generated by graphene p–n junctions in the quantum Hall effect regime

Graphene offers a unique system to investigate transport of Dirac Fermions at p–n junctions. In a magnetic field, combination of quantum Hall physics and the characteristic transport across p–n junctions leads to a fractionally quantized conductance associated with the mixing of electron-like and hole-like modes and their subsequent partitioning. The mixing and partitioning suggest that a p–n junction could be used as an electronic beam splitter. Here we report the shot noise study of the mode-mixing process and demonstrate the crucial role of the p–n junction length. For short p–n junctions, the amplitude of the noise is consistent with an electronic beam-splitter behaviour, whereas, for longer p–n junctions, it is reduced by the energy relaxation. Remarkably, the relaxation length is much larger than typical size of mesoscopic devices, encouraging using graphene for electron quantum optics and quantum information processing.

Supercurrent reversal in Josephson junctions based on bilayer graphene flakes

We investigate the Josephson effect in a bilayer graphene flake contacted by two monolayer sheet deposited by superconducting electrodes. It is found that when the electrodes are attached to the different layers of the bilayer, the Josephson current is in a $\pi$ state when the bilayer region is undoped and in the absence of vertical bias. Applying doping or bias to the junction reveals $\pi-0$ transitions which can be controlled by varying the temperature and the junction length. The supercurrent reversal here is very different from the ferromagnetic Josephson junctions where the spin degree of freedom plays the key role. We argue that the scattering processes accompanied by layer and sublattice index change give rise to the scattering phases which their effect varies with doping and the bias. Such scattering phases are responsible for the $\pi-0$ transitions. On the other hand if both of the electrodes are coupled to the same layer of the flake or the flake has AA stacking instead of common AB, the junction will be always in $0$ state since layer or sublattice index is not changed.

Topological Josephsonϕ0junctions

We study the effect of a magnetic field on the current-phase relation of a topological Josephson junction formed by connecting two superconductors through the helical edge states of a quantum spin-Hall insulator. We predict that the Zeeman effect along the spin quantization axis of the helical edges results in an anomalous Josephson relation that allows for a supercurrent to flow in the absence of superconducting phase bias. We relate the associated field-tunable phase shift $\phi_0$ in the Josephson relation of such a $\phi_0$-junction to the existence of a so-called helical superconductivity, which may result from the interplay of the Zeeman effect and spin-orbit coupling. We analyze the dependence of the magneto-supercurrent on the junction length and discuss its observability in suitably designed hybrid structures subject to an in-plane magnetic field.

Orbital Josephson interference in a nanowire proximity-effect junction

A semiconductor nanowire based superconductor-normal-superconductor (SNS) junction is modeled theoretically. A magnetic field is applied along the nanowire axis, parallel to the current. The Bogoliubov-de Gennes equations for Andreev bound states are solved while considering the electronic subbands due to radial confinement in the $N$ section. The energy-versus-phase curves of the Andreev bound states shift in phase as the $N$-section quasiparticles with orbital angular momentum couple to the axial field. A similar phase shift is observed in the continuum current of the junction. The quantum mechanical result is shown to reduce to an intuitive, semiclassical model when the Andreev approximation holds. Numerical calculations of the critical current versus axial field reveal flux-aperiodic oscillations that we identify as a novel form of Josephson interference due to this orbital subband effect. This behavior is studied as a function of junction length and chemical potential. Finally, we discuss extensions to the model that may be useful for describing realistic devices.

Revalidation of the spider genus Citharoceps Chamberlin, 1924 (Araneae, Segestriidae).

Citharoceps Chamberlin was diagnosed by the presence of a very distinctive stridulatory apparatus composed of two patches of ridges on the sides of the cephalic region, and a stridulatory thorn on the prolateral region of the femur I. Currently, this genus is a junior synonym of Ariadna Audouin, with the assumption that the stridulatory apparatus could constitute an exclusive feature of its unique known species, Citharoceps fidicina Chamberlin, currently senior synonym of Citharoceps californica Chamberlin & Ivie. In the present study, Citharoceps is revalidated and redescribed based on the occurrence of the stridulatory apparatus in Citharoceps fidicina and Segestria cruzana Chamberlin & Ivie, and also on the presence of distinguishable characters, such as the length of the labium-sternum junction, ventral median spine on male metatarsi I, and strong sclerotized interpulmonary fold in females, forming a conspicuous median flap. Segestria cruzana is transfered to Citharoceps, with Citharoceps californica removed from the synonym of Citharoceps fidicina, and proposed as a junior synonym of Citharoceps cruzana, due to the similarity between the additional material examined and the original description. Males of Citharoceps fidicina and Citharoceps cruzana are described for the first time.

CAMP Signaling Strengthens Cardiomyocyte Cohesion

Cardiomyocytes are electrically and mechanically coupled via intercalated discs (ICDs) composed of desmosomes, adherens junctions and gap junctions. The desmosomal cadherins desmoglein 2 (Dsg2) and desmocollin 2 and the classical cadherin N‐cadherin are the transmembrane adhesion molecules of the ICD and provide intercellular adhesive strength. Gap junctions dynamically remodel to adapt to cyclic adenosine 5′‐monophosphate (cAMP) signaling. It is unknown whether such rapid adaption also is evident for the adhesive function of the ICD. Atomic force microscopy revealed that cAMP signaling enhanced the number of Dsg2‐specific interactions along cell junctions and elevated their binding forces. This was accompanied by increased cell cohesion in cardiomyocyte cultures and murine heart slices. Enhanced Dsg2 staining along cell borders and increased junction length reflected cAMP‐induced reorganization of ICDs. cAMP signaling induced PKA‐dependent phosphorylation of the ICD plaque protein plakoglobin (Pg). In line with this, Pg deficiency abrogated cAMP‐mediated junctional remodeling and prevented increased cohesion in cardiac slices. Here we provide evidence that cAMP signaling strengthens cardiomyocyte cohesion in a Pg‐dependent manner. This mechanism may be of high medical relevance because reduced Pg levels at intercalated discs were shown to be a consistent feature of arrythmogenic cardiomyopathy.

PRIMARY PREVENTION OF POSTOPERATIVE REFLUX DISEASE

Creation of anastomoses between hollow organs of the abdominal cavity, retroperitoneal space and the small intestine always raises the question of the prevention of reflux from the small intestine into the cavity drained the esophagus, stomach, gallbladder, liver outer duct cysts of the liver and pancreas. After surgery, any reflux becomes pathological. Reflux – is an obligate precancer. So, throw the bile and pancreatic juices in the stomach, the stump of the stomach, esophagus contributes to reflux esophagitis, reflux gastritis, ulcers and gastric cancer, or a stump. After an internal drainage of cavity formation in the small intestine develops postoperative reflux disease, which is caused by the actions of the surgeon who tried sincerely to help the patient. It is possible to give the definition of such states “Iatrogenic Postoperative Reflux Disease”.The aim of this work was to develop and put into practice a “cap” on the afferent loop of the small intestine, do not migrate into the gut lumen, with an internal cavity drainage structures of the abdominal cavity and retroperitoneal space and to evaluate clinical outcomes. As a result, the authors have developed a way to create a “cap” on a loop of the small intestine, which is used for the drainage of cavity formation, conducted research on its safety, proper functioning, accessibility, analyzed the clinical situation offers. For drainage of cavernous fistula formation impose between him and a loop of small intestine 40–50 cm from the Treitz ligament. Form a intestine anastomosis by Brown.Above this junction length leads to the formation of the drained portion of the small intestine is about 10 cm, in the middle of which impose a “stub”. Length of discharge from the drainage area of education of the small intestine to interintestinal Brownian anastomosis is about 30 cm. To form a “plug” free land use of the greater omentum, through which by puncture-poke perform ligature of non-absorbable polypropylene material. The developed method for forming a “plug” does not cause drastic changes in the ischemic zone of operation, followed by necrosis of the bowel wall and migration "stub" into the lumen, and its efficiency is demonstrated by clinical observation of microcirculation studies, the results of the water sample, and radiological studies. Way to create a “stub” is promising for internal drainage of abdominal structures of the abdominal cavity and retroperitoneal space, to form a nutrient anti reflux eyunostomy.

Valley featured electronic transport of pn junction in silicene ribbon

Abstract We calculated the conductance of silicene pn junction in the bipolar region using the non-equilibrium retarded Green's function method. When an electrical field is applied normally, the energy gaps of valleys K and K ′ become different. The conductance of pn junctions is mainly determined by the transport of electrons of the valley with the smaller gap, and the conductance of the other valley can also be observed for short junctions. For the spin–orbit coupling dominant cases, edge state bands lie in the bulk gap and contribute a unit tunneling conductance plateau, which is independent of the junction length. When changing electrical field continuously, the conductance peaks at a certain position for long junctions but decreases monotonically for short junctions. We explained all these features based on a simple subband tunneling model.

Core-shell structure, biodegradation, and drug release behavior of poly(lactic acid)/poly(ethylene glycol) block copolymer micelles tuned by macromolecular stereostructure.

Poly(ethylene glycol)-b-poly(L-lactic acid)-b-poly(D-lactic acid) (PEG-b-PLLA-b-PDLA) stereoblock copolymers were synthesized by sequential ring-opening polymerization. Their micelle formation, precise micelle structure, biodegradation, and drug release behavior were systematically investigated and compared with the PEG-b-poly(lactic acid) (PEG-b-PLA) diblock copolymers with various PLA stereostructures and PEG-b-PLLA/PEG-b-PDLA enantiomeric mixture. Stereoblock copolymers having comparable PLLA and PDLA block lengths and enantiomerically-mixed copolymers assemble into the stereocomplexed core-shell micelles, while the isotactic and atactic PEG-b-PLA copolymers formed the homocrystalline and amorphous micelles, respectively. The PLA segments in stereoblock copolymer micelles show smaller crystallinity than those in the isotactic and enantiomerically-mixed ones, attributed to the short block length and presence of covalent junction between PLLA and PDLA blocks. As indicated by the synchrotron radiation small-angle X-ray scattering results, the stereoblock copolymer micelles have larger size, micellar aggregation number, core radius, smaller core density, and looser packing of core-forming segments than the isotactic and enantiomerically-mixed copolymer micelles. These unique structural characteristics cause the stereoblock copolymer micelles to possess higher drug loading content, slower degradation, and drug release rates.

Normal esophageal pressure topography metrics for data derived from the Sandhill‐Unisensor high‐resolution manometry assembly in supine and sitting positions

Normal values of the esophageal motor function parameters for high-resolution manometry (HRM-EPT) adopted by the Chicago classification were established using the proprietary system of Given Imaging. It is conceivable that normal values of a system do not apply to data from others. Most studies using HRM were based on supine swallows, whereas deglutition occurs mostly in the upright position. We wished to establish normal values for HRM-EPT parameters obtained with the Sandhill's HRM-EPT system and compare the results in supine and sitting positions. Sixty-nine healthy volunteers, 38 females, median age 27years, were included in this study. All underwent supine HRM, and 34 of them underwent sitting HRM, with at least 10 single 5-mL swallows for analysis obtained in each position. The normal range (5-95th percentiles) for the following parameters was calculated: distal contractile integral (DCI), 606-4998mmHg·s·cm; contractile front velocity (CFV), 2.0-6.5cm/s; distal latency (DL), 5.1-8.8s; intrabolus pressure (IBP), 1.9-17.6mmHg; upper esophageal sphincter (UES) pressure, 45.2-186.9mmHg; esophagogastric junction (EGJ) length, 1.8-4cm; EGJ resting pressure, 8.1-61.6mmHg, and integrated relaxation pressure (IRP) 2.5-23.5mmHg. Normal values of EGJ resting pressure, IRP, DCI, and IBP but not CFV, DL, and UES resting pressure were significantly lower in the sitting posture. Studies performed with Sandhill's HRM-EPT system should use its own specific normal data. Normal values should be established for different study.

Internal stress drives slow glassy dynamics and quake-like behaviour in ionotropic pectin gels

Frustrated, out-of-equilibrium materials have been of considerable interest for some time and continue to be some of the least understood materials. Recent measurements have shown that many gelled biopolymer materials display slow dynamics on timescales greater than one second, that are not accessible with typical methods, and are characteristic of glassy trapped systems. In this study we have controlled the fine structure of the anionic polysaccharide pectin in order to construct a series of ionotropic gels having differing binding energies between the constituent chains, in an attempt to further understand the slow dynamical processes occurring. Using multi-speckle light scattering techniques it is shown that the slow dynamics observed in these gelled systems are stress-driven. As the binding lengths, and thus the binding energies, of the junction zones between the polymer chains in these networks increase the long-time dynamics initially slow, as might be expected, until a critical level of internal stress is reached upon which the dynamics increase significantly, with gentle creaking punctuated by localised stress-relieving quakes.

Length dependence of electron transport through molecular wires--a first principles perspective.

One-dimensional wires constitute a fundamental building block in nanoscale electronics. However, truly one-dimensional metallic wires do not exist due to Peierls distortion. Molecular wires come close to being stable one-dimensional wires, but are typically semiconductors, with charge transport occurring via tunneling or thermally-activated hopping. In this review, we discuss electron transport through molecular wires, from a theoretical, quantum mechanical perspective based on first principles. We focus specifically on the off-resonant tunneling regime, applicable to shorter molecular wires (<∼4-5 nm) where quantum mechanics dictates electron transport. Here, conductance decays exponentially with the wire length, with an exponential decay constant, beta, that is independent of temperature. Different levels of first principles theory are discussed, starting with the computational workhorse - density functional theory (DFT), and moving on to many-electron GW methods as well as GW-inspired DFT + Sigma calculations. These different levels of theory are applied in two major computational frameworks - complex band structure (CBS) calculations to estimate the tunneling decay constant, beta, and Landauer-Buttiker transport calculations that consider explicitly the effects of contact geometry, and compute the transmission spectra directly. In general, for the same level of theory, the Landauer-Buttiker calculations give more quantitative values of beta than the CBS calculations. However, the CBS calculations have a long history and are particularly useful for quick estimates of beta. Comparing different levels of theory, it is clear that GW and DFT + Sigma calculations give significantly improved agreement with experiment compared to DFT, especially for the conductance values. Quantitative agreement can also be obtained for the Seebeck coefficient - another independent probe of electron transport. This excellent agreement provides confirmative evidence of off-resonant tunneling in the systems under investigation. Calculations show that the tunneling decay constant beta is a robust quantity that does not depend on details of the contact geometry, provided that the same contact geometry is used for all molecular lengths considered. However, because conductance is sensitive to contact geometry, values of beta obtained by considering conductance values where the contact geometry is changing with the molecular junction length can be quite different. Experimentally measured values of beta in general compare well with beta obtained using DFT + Sigma and GW transport calculations, while discrepancies can be attributed to changes in the experimental contact geometries with molecular length. This review also summarizes experimental and theoretical efforts towards finding perfect molecular wires with high conductance and small beta values.

Conductance of a Single Molecule Junction Formed with Ni, Au, and Ag Electrodes

We measure the conductance of a 4,4'-diaminobiphenyl formed with Ni electrodes using a scanning tunneling microscope-based break-junction technique. For comparison, we use Au or Ag electrodes to form a metal-molecular junction. For molecules that conduct through the highest occupied molecular orbital, junctions formed with Ni show similar conductance as Au and are more conductive than those formed with Ag, consistent with the higher work function for Ni or Au. Furthermore, we observe that the measured molecular junction length that is formed with the Ni or Au electrodes was shorter than that formed with the Ag electrodes. These observations are attributed to a larger gap distance of the Ni or Au electrodes compared to that of the Ag electrodes after the metal contact ruptures. Since our work allows us to measure the conductance of a molecule formed with various electrodes, it should be relevant to molecular electronics with versatile materials.

ULTRASTRUCTURAL CHARACTERISTICS OF THE REMODELING VENTRICULAR ELECTRIC PATHWAYS BETWEEN CARDIOMYOCYTES AFTER THE INFLUENCE OF CHRONIC PRENATAL HYPOXIA IN EXPERIENCE

The aim of this work was to determine the influence of chronic prenatal hypoxia on remodeling of gap junctions in cardiomyocytes in rat ventricular myocardium at different stages of postnatal ontogeny. Chronic prenatal hypoxia to decline total and mean individual profile length of the gap junction per 100 μm intercalated disk in comparison with the norm, at 30 th day was decrease the amount of gap junctions per 100 μm intercalated disc in comparison of control level and caused predominantly violation build large gap junctions.

High probability of single molecule junction formation with Ag electrodes

We use a scanning tunneling microscope-based break-junction technique to compare the probability of the formation of a single-molecule junction for a series of amine-terminated oligophenyl and alkane species using either Ag or Au as electrodes. For all molecules, we find that there is a significantly higher probability of junction formation when using Ag electrodes than with Au electrodes. We also find that longer molecules have a higher probability than shorter molecules to form a junction for both Ag and Au electrodes. For all molecules, the measured molecular junction length that is formed with the Ag electrodes was longer than that formed with Au electrodes. Furthermore, we can make a single atomic oxygen junction and can measure its conductance using Ag electrodes. These observations are attributed to a narrower gap of the Ag electrodes compared to that of the Au electrodes after the metal contact ruptures. Since there is a high probability of a molecular junction forming when using Ag electrodes, we can therefore perform a statistical analysis within the context of the material properties that are suitable for future molecular electronics.

In vivo quantitative evaluation of vascular parameters for angiogenesis based on sparse principal component analysis and aggregated boosted trees

To solve the multicollinearity issue and unequal contribution of vascular parameters for the quantification of angiogenesis, we developed a quantification evaluation method of vascular parameters for angiogenesis based on in vivo micro-CT imaging of hindlimb ischemic model mice. Taking vascular volume as the ground truth parameter, nine vascular parameters were first assembled into sparse principal components (PCs) to reduce the multicolinearity issue. Aggregated boosted trees (ABTs) were then employed to analyze the importance of vascular parameters for the quantification of angiogenesis via the loadings of sparse PCs. The results demonstrated that vascular volume was mainly characterized by vascular area, vascular junction, connectivity density, segment number and vascular length, which indicated they were the key vascular parameters for the quantification of angiogenesis. The proposed quantitative evaluation method was compared with both the ABTs directly using the nine vascular parameters and Pearson correlation, which were consistent. In contrast to the ABTs directly using the vascular parameters, the proposed method can select all the key vascular parameters simultaneously, because all the key vascular parameters were assembled into the sparse PCs with the highest relative importance.

Gate-controlled supercurrent reversal in MoS2-based Josephson junctions

Motivated by recent experiments revealing superconductivity in , we investigate the Josephson effect in the monolayer in the presence of an exchange splitting. We show that the supercurrent reversal known as transition can occur by varying the doping via gate voltages. This is in contrast to common superconductor/ferromagnet/superconductor junctions in which successive transitions take place with the variation of junction length or temperature. In fact for the case of we find that both the amplitude and the period of oscillations show a dependence on the doping which explains the predicted doping-induced supercurrent reversal. These effects comes from the dependence of density and Fermi velocity on the doping strength beside the intrinsic spin-splitting in the valence band which originates from spin-orbit interaction.