Conductance of a Mott Quantum Wire

We consider transport through a one-dimensional conductor subject to an external periodic potential and connected to non-interacting leads (a "Mott quantum wire"). For the case of a strong periodic potential, the conductance is shown to jump from zero, for the chemical potential lying within the Mott-Hubbard gap, to the non-interacting value of 2e^2/h, as soon as the chemical potential crosses the gap edge. This behavior is strikingly different from that of an optical conductivity, which varies continuously with the carrier concentration. For the case of a weak potential, the perturbative correction to the conductance due to Umklapp scattering is absent away from half-filling.Comment: 4 pages, RevTex, 1 ps figure included; published versio

Quasi-Andreev reflection in inhomogeneous Luttinger liquids

Reflection of charge excitations at the step in the interaction strength in a Luttinger liquid can be of the Andreev type, even if the interactions are purely repulsive. The region with stronger repulsion plays the role of a normal metal in a normal-metal /superconductor junction, whereas the region with weaker repulsion plays the role of a superconductor. It is shown that this quasi-Andreev reflection leads to a number of proximity-like effects, including the local enhancement (suppression) of superconducting fluctuations on the quasi-normal (quasi-superconducting) side of the step, significant modification of the local density of states, as well as others. The observable consequences of these proximity effects are analyzed for the case of single- and two-particle tunneling from a normal-metal or superconducting tip into an inhomogeneous Luttinger-liquid wire.Comment: 5 pages, 2 figures (eps

Interactions and Disorder in Multi-Channel Quantum Wires

Recent experiments have revealed that the temperature dependence of the conductance of quasi-ballistic quantum wires bears clear features of the Luttinger-liquid state. In this paper, the conductance of an N-channel quantum wire is calculated within the model of N coupled Luttinger liquids and under the assumption of weak disorder. It is shown that as the number of channels increases, a crossover from the Luttinger-liquid to the Fermi-liquid behavior occurs. This crossover manifests itself in the 1/N decrease of the scaling exponent of the temperature dependence. An exact expression for the scaling exponent for the case of N coupled Luttinger chains is obtained, and the large N limit is studied for the case of a quantum wire. The case of N=2 for electrons with spin is analyzed in detail, and a qualitative agreement with the experiment is achieved.Comment: 9 pages, REVTex with 1 Postscript figur

The efficacy of the combination of eribulin and trastuzumab in advanced HER2-positive breast cancer: the results of Russian observational study

The article presents the experience of 19 Russian medical institutions on the use of eribulin in combination with trastuzumab in various treatment lines of metastatic HER2+ breast cancer in routine clinical practice. Aim. The main objective of this retrospective observational study was to evaluate the efficacy and tolerability of eribulin and trastuzumab combo in HER2+ breast cancer patients pretreated with anthracyclines and taxanes. The analysis included 60 patients who received at least 2 cycles of eribulin in combination with trastuzumab. 2 patients (3.3%) received treatment as the 1st line, as the 2nd 14 (23.3%), as the 3rd 16 (26.7%), and as the 4th and more 28 (46.7%). Materials and methods. Complete response was achieved in 2 (3.3%) patients, partial response in 9 (15%), stable disease in 33 (55%), stabilization for more than 6 months in 11 (18.3%), disease progression was detected in 16 (26.7%) patients. The objective response rate was 18.3% in the whole group, the clinical benefit rate 36.7%. Results. The objective response rate in the group of the luminal subtype (ER/PR+HER2+) was 26.9%, in HER2-overexpressed subtype (ER-PR-HER2+) 8.8% and 64.7%, respectively, disease progression was recorded 2.3 times more often 35.3% versus 15.5% in the luminal subtype group. The median progression-free survival in patients with HER2+ breast cancer was 4.95 months (95% confidence interval CI 3.048.29 months), in luminal subtype 6.38 months (95% CI 3.338.54 months), in non-luminal 4.44 months (95% CI 2.47.96 months); p=0.306. The treatment was well tolerated, the spectrum of adverse events corresponded to the eribulin toxicity profile. Conclusions. The uniqueness of this study lies in the fact that on a large clinical material from the standpoint of real clinical practice, a very promising treatment regimen that is not used routinely in a number of countries has been studied, its effectiveness and satisfactory tolerance have been confirmed

Healthy pediatric platelets are moderately hyporeactive in comparison with adults’ platelets

Studies on platelet function in children older than neonatal period are few and their results are controversial. The pediatric platelets were alternatively reported to be more active or less active than adults’ ones. We compared platelet function in the several age groups of children to adults and evaluated the age when platelet function reaches the adults’ status. The study included 76 healthy children and 49 healthy adult volunteers. Types of platelet activation used included: collagen-related peptide (CRP) and PAR-1 activating peptide SFLLRN; SFLLRN, PAR-4 activating peptide AYPGKF and adenosine diphosphate (ADP); ADP. The parameters determined included forward (FSC) and side scatter (SSC), CD42b, CD61, CD62P, PAC-1, annexin V binding and mepacrine release levels. Resting pediatric platelets were similar to adults’ platelets except for 1.2-fold decreased FSC and dense granules volume in youngest children, and 2.5-fold increased annexin V level in children aged 1–10 years. After CRP+SFLLRN stimulation, pediatric platelets had a 1.2-fold lower alpha- and 1.1-fold lower dense granule release than adults. For SFLLRN+AYPGKF+ADP stimulation, this was observed only for youngest children. The response to ADP stimulation was identical for pediatric platelets and adults. Pediatric platelets have lower granular release than adults’ platelets, which persists until the age of 18

Platelet function and blood coagulation system status in childhood essential thrombocythemia

Childhood essential thrombocythemia (ET) is a rare chronic myeloproliferative disorder. The quality of life of ET patients may decrease as a result of ischemic and hemorrhagic complications of unclear origin. Our goal was to characterize the hemostatic system in children with ET. We genotyped and investigated blood samples from 20 children with ET in a prospective case series study using platelet aggregation, functional flow cytometry (FC) assay and standard clotting assays. Three children had a JAK2V617F mutation, 4 had mutations in CALR and 13 were triple-negative. Myelofibrosis in stage 1-2 was detected in 3 children. Three patients had bleeding episodes and seven had ischemic events. Aggregation in response to collagen, adenosine diphosphate, and ristomycin was decreased in all patients. In FC, significant changes in the whole patient group compared to the healthy children control group were decrease in the resting forward scatter and PAC1 binding (activated GPIIb/IIIa) level. For the activated platelets, dense granules release (by mepacrine), PAC1, and GPIIb/IIIa levels were significantly decreased. GPIb/V/IX, P-selectin, and phosphatidylserine levels manifested only moderate differences. Forward and side scatter changes in response to stimulation (representing shape change) and dense granules release were significantly lower in the 3 patients with bleeding than in the 17 patients without hemorrhage. Activated partial thromboplastin time was slightly prolonged, prothrombin index was slightly shortened and thrombin time was normal, while fibrinogen was mildly decreased in the ET patients. It could be concluded that the observed platelet function defects could be related to bleeding in ET, and be potentially used as a marker