Incipient Formation of an Electron Lattice in a Weakly Confined Quantum Wire

We study the low-temperature transport properties of 1D quantum wires as the confinement strength V-conf and the carrier density n(1D) are varied using a combination of split gates and a top gate in GaAs/AlGaAs heterostructures. At intermediate V-conf and n(1D), we observe a jump in conductance to 4e(2)/h, suggesting a double wire. On further reducing n(1D), plateau at 2e(2)/h returns. Our results show beginnings of the formation of an electron lattice in an interacting quasi-1D quantum wire. In the presence of an in-plane magnetic field, mixing of spin-aligned levels of the two wires gives rise to more complex states

Spin-incoherent transport in quantum wires

When a quantum wire is weakly confined, a conductance plateau appears at e(2)/h with decreasing carrier density in zero magnetic field accompanied by a gradual suppression of the 2e(2)/h plateau. Applying an in-plane magnetic field B-parallel to does not alter the value of this quantization; however, the e(2)/h plateau weakens with increasing B-parallel to up to 9 T, and then strengthens on further increasing B-parallel to, which also restores the 2e(2)/h plateau. Our results are consistent with spin-incoherent transport in a one-dimensional wire

Extreme sensitivity of the spin-splitting and 0.7 anomaly to confining potential in one-dimensional nanoelectronic devices

Quantum point contacts (QPCs) have shown promise as nanoscale spin-selective components for spintronic applications and are of fundamental interest in the study of electron many-body effects such as the 0.7 x 2e^2/h anomaly. We report on the dependence of the 1D Lande g-factor g* and 0.7 anomaly on electron density and confinement in QPCs with two different top-gate architectures. We obtain g* values up to 2.8 for the lowest 1D subband, significantly exceeding previous in-plane g-factor values in AlGaAs/GaAs QPCs, and approaching that in InGaAs/InP QPCs. We show that g* is highly sensitive to confinement potential, particularly for the lowest 1D subband. This suggests careful management of the QPC's confinement potential may enable the high g* desirable for spintronic applications without resorting to narrow-gap materials such as InAs or InSb. The 0.7 anomaly and zero-bias peak are also highly sensitive to confining potential, explaining the conflicting density dependencies of the 0.7 anomaly in the literature.Comment: 23 pages, 7 figure

Avapritinib versus regorafenib in locally advanced unresectable or metastatic GI stromal tumor: A randomized, open-label phase III study

PURPOSE Primary or secondary mutations in KIT or platelet-derived growth factor receptor alpha (PDGFRA) underlie tyrosine kinase inhibitor resistance in most GI stromal tumors (GISTs). Avapritinib selectively and potently inhibits KIT- and PDGFRA-mutant kinases. In the phase I NAVIGATOR study (NCT02508532), avapritinib showed clinical activity against PDGFRA D842V–mutant and later-line KIT-mutant GIST. VOYAGER (NCT03465722), a phase III study, evaluated efficacy and safety of avapritinib versus regorafenib as third-line or later treatment in patients with unresectable or metastatic GIST. PATIENTS AND METHODS VOYAGER randomly assigned patients 1:1 to avapritinib 300 mg once daily (4 weeks continuously) or regorafenib 160 mg once daily (3 weeks on and 1 week off). Primary end point was progression-free survival (PFS) by central radiology per RECIST version 1.1 modified for GIST. Secondary end points included objective response rate, overall survival, safety, disease control rate, and duration of response. Regorafenib to avapritinib crossover was permitted upon centrally confirmed disease progression. RESULTS Four hundred seventy-six patients were randomly assigned (avapritinib, n 5 240; regorafenib, n 5 236). Median PFS was not statistically different between avapritinib and regorafenib (hazard ratio, 1.25; 95% CI, 0.99 to 1.57; 4.2 v 5.6 months; P 5 .055). Overall survival data were immature at cutoff. Objective response rates were 17.1% and 7.2%, with durations of responses of 7.6 and 9.4 months for avapritinib and regorafenib; disease control rates were 41.7% (95% CI, 35.4 to 48.2) and 46.2% (95% CI, 39.7 to 52.8). Treatment-related adverse events (any grade, grade $ 3) were similar for avapritinib (92.5% and 55.2%) and regorafenib (96.2% and 57.7%). CONCLUSION Primary end point was not met. There was no significant difference in median PFS between avapritinib and regorafenib in patients with molecularly unselected, late-line GIST

Structure and evolutionary origin of Ca2+-dependent herring type II antifreeze protein

10.1371/journal.pone.0000548PLoS ONE26

Generation of an NCS1 gene knockout human induced pluripotent stem cell line using CRISPR/Cas9

NCS1 (Neuronal calcium sensor protein 1) encodes a highly conserved calcium binding protein abundantly expressed in neurons. It modulates intracellular calcium homeostasis, calcium-dependent signaling pathways as well as neuronal transmission and plasticity. Here, we generated a NCS1 knockout human induced pluripotent stem cell (hiPSC) line using CRISPR-Cas9 genome editing. It shows regular expression of pluripotent markers, normal iPSC morphology and karyotype as well as no detectable off-target effects on top 6 potentially affected genes. This newly generated cell line constitutes a valuable tool for studying the role of NCS1 in the pathophysiology of various neuropsychiatric disorders and non-neurological disease

Asthma exacerbation and steroid burden in Australian primary care

Peer reviewedPostprin

Synthesis, Purification and Crystallization of Guanine-rich RNA Oligonucleotides

Guanine-rich RNA oligonucleotides display many novel structural motifs in recent crystal structures. Here we describe the procedures of the chemical synthesis and the purification of such RNA molecules that are suitable for X-ray crystallographic studies. Modifications of the previous purification methods allow us to obtain better yields in shorter time. We also provide 24 screening conditions that are very effective in crystallization of the guanine-rich RNA oligonucleotides. Optimal crystallization conditions are usually achieved by adjustment of the concentration of the metal ions and pH of the buffer. Crystals obtained by this method usually diffract to high resolution