Large linear magnetoresistance in heavily-doped Nb:SrTiO3 epitaxial thin films.

Interaction between electrons has long been a focused topic in condensed-matter physics since it has led to the discoveries of astonishing phenomena, for example, high-Tc superconductivity and colossal magnetoresistance (CMR) in strongly-correlated materials. In the study of strongly-correlated perovskite oxides, Nb-doped SrTiO3 (Nb:SrTiO3) has been a workhorse not only as a conducting substrate, but also as a host possessing high carrier mobility. In this work, we report the observations of large linear magnetoresistance (LMR) and the metal-to-insulator transition (MIT) induced by magnetic field in heavily-doped Nb:STO (SrNb0.2Ti0.8O3) epitaxial thin films. These phenomena are associated with the interplay between the large classical MR due to high carrier mobility and the electronic localization effect due to strong spin-orbit coupling, implying that heavily Nb-doped Sr(Nb0.2Ti0.8)O3 is promising for the application in spintronic devices.

Who may benefit from robotic gastrectomy?: A subgroup analysis of multicenter prospective comparative study data on robotic versus laparoscopic gastrectomy.

AIMS: Robotic gastrectomy for gastric cancer has been proven to be a feasible and safe minimally invasive procedure. However, our previous multicenter prospective study indicated that robotic gastrectomy is not superior to laparoscopic gastrectomy. This study aimed to identify which subgroups of patients would benefit from robotic gastrectomy rather than from conventional laparoscopic gastrectomy. METHODS: A prospective multicenter comparative study comparing laparoscopic and robotic gastrectomy was previously conducted. We divided the patients into subgroups according to obesity, type of gastrectomy performed, and extent of lymph node dissection. Surgical outcomes were compared between the robotic and laparoscopic groups in each subgroup. RESULTS: A total of 434 patients were enrolled into the robotic (n = 223) and laparoscopic (n = 211) surgery groups. According to obesity and gastrectomy type, there was no difference in the estimated blood loss (EBL), number of retrieved lymph nodes, complication rate, open conversion rate, and the length of hospital stay between the robotic and laparoscopic groups. According to the extent of lymph node dissection, the robotic group showed a significantly lower EBL than did the laparoscopic group after D2 dissection (P = 0.021), while there was no difference in EBL in patients that did not undergo D2 dissection (P = 0.365). CONCLUSION: Patients with gastric cancer undergoing D2 lymph node dissection can benefit from less blood loss when a robotic surgery system is used.

Spin dynamics in Na(4-x)Ir3O8 (x = 0.3 and 0.7) investigated by ²³Na NMR and µSR.

We report (23)Na nuclear magnetic resonance (NMR) and zero-field (ZF) and longitudinal-field (LF) muon spin relaxation (µSR) measurements of the depleted hyperkagome compounds Na(4-x)Ir3O8 (x = 0.3 and 0.7), which undergo an insulator-semimetal transition as a function of x. The (23)Na spin-lattice relaxation rates, T1(-1), follow a T(2.5) power law behavior at accessible temperatures of T = 120-350 K. A substantial temperature dependence of T1(-1) indicates the presence of gapped excitations at elevated temperatures through the transition to a semimetallic phase. ZF-µSR results reveal that hole-doping leads to a melting of quasi-static order to a dynamically fluctuating state. The very slow muon depolarization rate which varies hardly with temperature indicates that spins are close to an itinerant limit in the largest doping x = 0.7. The dynamic relaxation rates extracted from the LF-µSR spectra show a three-dimensional diffusive transport. Our combined NMR and µSR results suggest the occurrence of intriguing spin and charge excitations across the insulator-semimetal transition.

Broadband electron spin resonance at low frequency without resonant cavity.

We have developed a nonconventional broadband electron spin resonance (ESR) spectrometer operating continuously in the frequency range from 0.5 to 9 GHz. Dual antenna structure and the microwave absorbing environment differentiate the setup from the conventional one and enable broadband operation with any combination of frequency or magnetic field modulation and frequency or magnetic field sweeping. Its performance has been tested with the measurements on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) sample and with the measurements on the single molecular magnet, V6, in solid state at low temperature.

Inhomogeneous low frequency spin dynamics in La(1.65)Eu(0.2)Sr(0.15)CuO(4).

We report Cu and La nuclear magnetic resonance measurements in the title compound that reveal an inhomogeneous glassy behavior of the spin dynamics. A low temperature peak in the La spin lattice relaxation rate and the "wipeout" of Cu intensity both arise from these slow electronic spin fluctuations that reveal a distribution of activation energies. Inhomogeneous slowing of spin fluctuations appears to be a general feature of doped lanthanum cuprate.

Structural determinants of a glucocorticoid receptor recognition element.

Analysis of the relative inducibility of an extensive series of mutant glucocorticoid response elements (GREs) defines features critical to the constitution of an active GRE. Assuming that function as a GRE reflects binding of glucocorticoid receptor, our activity data are consistent with the recognition of the GRE as two hexamer half-sites, each half-site recognized by a single subunit of a receptor dimer, probably in a cooperative fashion. Integrity of both half-sites is necessary for an active element, and spacing of the half-sites is critical. The identity of 1 basepair within the hexamer half-site is unconstrained; the receptor probably makes no base-specific contacts at this position. In contrast, at other positions within the half-site, limited substitutions (if any) can be tolerated. These results along with data from certain insertion mutations suggest that the receptor recognizes each hexamer half-site as two separable subelements. A further implication is that the DNA-binding domain of the glucocorticoid receptor is composed of distinct subdomains, which interact with the subelements of the recognition sequence.