Transport Properties of Doped t-J Ladders

Conductivity and Hall coefficient for various types of t-J ladders are calculated as a function of temperature and frequency by numerical diagonalization. A crossover from an incoherent to a coherent charge dynamics is found at a temperature T_{coh}. There exists another crossover at T_{PG} below which a pseudogap opens in the optical spectra, induced by the opening of a spin gap. In the absence of the spin gap, T_{coh} and the coherent weight are suppressed especially with increasing dimensionality. On the contrary, T_{coh} is strongly enhanced by the pseudogap formation below T_{PG}, where the coherent Drude weight decreases with increasing dimensionality. The Hall coefficient shows a strong crossover at T_{PG} below which it has large amplitude for small doping concentration.Comment: 4 pages, RevTeX, 5 PostScript figure

recount3: summaries and queries for large-scale RNA-seq expression and splicing

We present recount3, a resource consisting of over 750,000 publicly available human and mouse RNA sequencing (RNA-seq) samples uniformly processed by our new Monorail analysis pipeline. To facilitate access to the data, we provide the recount3 and snapcount R/Bioconductor packages as well as complementary web resources. Using these tools, data can be downloaded as study-level summaries or queried for specific exon-exon junctions, genes, samples, or other features. Monorail can be used to process local and/or private data, allowing results to be directly compared to any study in recount3. Taken together, our tools help biologists maximize the utility of publicly available RNA-seq data, especially to improve their understanding of newly collected data. recount3 is available from http://rna.recount.bio

Non-Fermi liquid regime of a doped Mott insulator

We study the doping of a Mott insulator in the presence of quenched frustrating disorder in the magnetic exchange. A low doping regime $\delta<J/t$ is found, in which the quasiparticle coherent scale is low : $\epsilon_F^* = J (\delta/\delta^*)^2$ with $\delta^*=J/t$ (the ratio of typical exchange to hopping). In the ``quantum critical regime'' $\epsilon_F^*<T<J$, several physical quantities display Marginal Fermi Liquid behaviour : NMR relaxation time $1/T_1\sim const.$, resistivity $\rho_{dc}(T) \propto T$, optical lifetime \tau_{opt}^{-1}\propto \omega/\ln(\omega/\epstar) and response functions obey $\omega/T$ scaling, e.g. $J\sum_q \chi''(q,\omega) \propto \tanh (\omega/2T)$. In contrast, single-electron properties display stronger deviations from Fermi liquid theory in this regime with a $\sqrt{\omega}$ dependence of the inverse single-particle lifetime and a $1/\sqrt{\omega}$ decay of the photoemission intensity. On the basis of this model and of various experimental evidence, it is argued that the proximity of a quantum critical point separating a glassy Mott-Anderson insulator from a metallic ground-state is an important ingredient in the physics of the normal state of cuprate superconductors (particularly the Zn-doped materials). In this picture the corresponding quantum critical regime is a ``slushy'' state of spins and holes with slow spin and charge dynamics responsible for the anomalous properties of the normal state.Comment: 40 pages, RevTeX, including 13 figures in EPS. v2 : minor changes, some references adde

VSOP/Hv1 proton channels sustain calcium entry, neutrophil migration, and superoxide production by limiting cell depolarization and acidification

Neutrophils kill microbes with reactive oxygen species generated by the NADPH oxidase, an enzyme which moves electrons across membranes. Voltage-gated proton channels (voltage-sensing domain only protein [VSOP]/Hv1) are required for high-level superoxide production by phagocytes, but the mechanism of this effect is not established. We show that neutrophils from VSOP/Hv1−/− mice lack proton currents but have normal electron currents, indicating that these cells have a fully functional oxidase that cannot conduct protons. VSOP/Hv1−/− neutrophils had a more acidic cytosol, were more depolarized, and produced less superoxide and hydrogen peroxide than neutrophils from wild-type mice. Hydrogen peroxide production was rescued by providing an artificial conductance with gramicidin. Loss of VSOP/Hv1 also aborted calcium responses to chemoattractants, increased neutrophil spreading, and decreased neutrophil migration. The migration defect was restored by the addition of a calcium ionophore. Our findings indicate that proton channels extrude the acid and compensate the charge generated by the oxidase, thereby sustaining calcium entry signals that control the adhesion and motility of neutrophils. Loss of proton channels thus aborts superoxide production and causes a severe signaling defect in neutrophils

Low-Frequency Crossover of the Fractional Power-Law Conductivity in SrRuO

We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO{sub 3} over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals

Upper abdominal body shape is the risk factor for postoperative pancreatic fistula after splenectomy for advanced gastric cancer: A retrospective study

<p>Abstract</p> <p>Background</p> <p>Postoperative pancreas fistula (POPF) is a major complication after total gastrectomy with splenectomy. We retrospectively studied the effects of upper abdominal shape on the development of POPF after gastrectomy.</p> <p>Methods</p> <p>Fifty patients who underwent total gastrectomy with splenectomy were studied. The maximum vertical distance measured by computed tomography (CT) between the anterior abdominal skin and the back skin (U-APD) and the maximum horizontal distance of a plane at a right angle to U-APD (U-TD) were measured at the umbilicus. The distance between the anterior abdominal skin and the root of the celiac artery (CAD) and the distance of a horizontal plane at a right angle to CAD (CATD) were measured at the root of the celiac artery. The CA depth ratio (CAD/CATD) was calculated.</p> <p>Results</p> <p>POPF occurred in 7 patients (14.0%) and was associated with a higher BMI, longer CAD, and higher CA depth ratio. However, CATD, U-APD, and U-TD did not differ significantly between patients with and those without POPF. Logistic-regression analysis revealed that a high BMI (≥25) and a high CA depth ratio (≥0.370) independently predicted the occurrence of POPF (odds ratio = 19.007, p = 0.002; odds ratio = 13.656, p = 0.038, respectively).</p> <p>Conclusion</p> <p>Surgical procedures such as total gastrectomy with splenectomy should be very carefully executed in obese patients or patients with a deep abdominal cavity to decrease the risk of postoperative pancreatic fistula. BMI and body shape can predict the risk of POPF simply by CT.</p

Microplate analytical method for quinones by pulse photo-irradiation and chemiluminescence detection

Quinones are widely distributed in nature and have various bioactivities. Besides, quinones are also considered as toxicological intermediates which cause severe dangerous effects. Hereby, a sensitive, simple, and rapid method is reported for quinones determination. The proposed method employed time resolved fluorescence (TRF) microplate reader based chemiluminescent (CL) detection for the first time as a novel approach for measurement. Under pulse photo-irradiation, the unique photochemical characteristic of quinones is exploited to liberate reactive oxygen species (ROS) which reacted with photosensitized CL reagent. L-012, luminol analogue, was selected for its high sensitivity. Under our investigation, para-quinones showed high CL response when compared to ortho-quinones. A linear response was obtained for studied quinone concentrations in the range of 0.05-50 μM for 1,4-naphthquinone and of 0.05-150 μM for 2-methyl-1,4-naphthoquinone (menadione) and 9,10-anthraquinone with detection limit (blank + 3SD) of 0.01 μM. The proposed method allowed the rapid determination of large number of samples in very short time (96 sample/125 s). The proposed method was successfully applied for determination of menadione in spiked human serum