Electron-Spin Excitation Coupling in an Electron Doped Copper Oxide Superconductor

High-temperature (high-Tc) superconductivity in the copper oxides arises from electron or hole doping of their antiferromagnetic (AF) insulating parent compounds. The evolution of the AF phase with doping and its spatial coexistence with superconductivity are governed by the nature of charge and spin correlations and provide clues to the mechanism of high-Tc superconductivity. Here we use a combined neutron scattering and scanning tunneling spectroscopy (STS) to study the Tc evolution of electron-doped superconducting Pr0.88LaCe0.12CuO4-delta obtained through the oxygen annealing process. We find that spin excitations detected by neutron scattering have two distinct modes that evolve with Tc in a remarkably similar fashion to the electron tunneling modes in STS. These results demonstrate that antiferromagnetism and superconductivity compete locally and coexist spatially on nanometer length scales, and the dominant electron-boson coupling at low energies originates from the electron-spin excitations.Comment: 30 pages, 12 figures, supplementary information include

Synergistic effect of intrathecal fentanyl and bupivacaine in spinal anesthesia for cesarean section

BACKGROUND: Potentiating the effect of intrathecal local anesthetics by addition of intrathecal opiods for intra-abdominal surgeries is known. In this study by addition of fentanyl we tried to minimize the dose of bupivacaine, thereby reducing the side effects caused by higher doses of intrathecal bupivacaine in cesarean section. METHODS: Study was performed on 120 cesarean section parturients divided into six groups, identified as B(8), B(10 )and B (12.5 )8.10 and 12.5 mg of bupivacaine mg and FB(8), FB(10 )and FB (12.5 )received a combination of 12.5 μg intrathecal fentanyl respectively. The parameters taken into consideration were visceral pain, hemodynamic stability, intraoperative sedation, intraoperative and postoperative shivering, and postoperative pain. RESULTS: Onset of sensory block to T6 occurred faster with increasing bupivacaine doses in bupivacaine only groups and bupivacaine -fentanyl combination groups. Alone lower concentrations of bupivacaine could not complete removed the visceral pain. Blood pressure declined with the increasing concentration of Bupivacaine and Fentanyl. Incidence of nausea and shivering reduces significantly whereas, the postoperative pain relief and hemodynamics increased by adding fentanyl. Pruritis, maternal respiratory depression and changes in Apgar score of babies do not occur with fentanyl. CONCLUSION: Spinal anesthesia among the neuraxial blocks in obstetric patients needs strict dose calculations because minimal dose changes, complications and side effects arise, providing impetus for this study. Here the synergistic, potentiating effect of fentanyl (an opiod) on bupivacaine (a local anesthetic) in spinal anesthesia for cesarian section is presented, fentanyl is able to reduce the dose of bupivacaine and therefore its harmful effects

Missing value imputation in high-dimensional phenomic data: Imputable or not, and how?

Background: In modern biomedical research of complex diseases, a large number of demographic and clinical variables, herein called phenomic data, are often collected and missing values (MVs) are inevitable in the data collection process. Since many downstream statistical and bioinformatics methods require complete data matrix, imputation is a common and practical solution. In high-throughput experiments such as microarray experiments, continuous intensities are measured and many mature missing value imputation methods have been developed and widely applied. Numerous methods for missing data imputation of microarray data have been developed. Large phenomic data, however, contain continuous, nominal, binary and ordinal data types, which void application of most methods. Though several methods have been developed in the past few years, not a single complete guideline is proposed with respect to phenomic missing data imputation. Results: In this paper, we investigated existing imputation methods for phenomic data, proposed a self-training selection (STS) scheme to select the best imputation method and provide a practical guideline for general applications. We introduced a novel concept of "imputability measure" (IM) to identify missing values that are fundamentally inadequate to impute. In addition, we also developed four variations of K-nearest-neighbor (KNN) methods and compared with two existing methods, multivariate imputation by chained equations (MICE) and missForest. The four variations are imputation by variables (KNN-V), by subjects (KNN-S), their weighted hybrid (KNN-H) and an adaptively weighted hybrid (KNN-A). We performed simulations and applied different imputation methods and the STS scheme to three lung disease phenomic datasets to evaluate the methods. An R package "phenomeImpute" is made publicly available. Conclusions: Simulations and applications to real datasets showed that MICE often did not perform well, KNN-A, KNN-H and random forest were among the top performers although no method universally performed the best. Imputation of missing values with low imputability measures increased imputation errors greatly and could potentially deteriorate downstream analyses. The STS scheme was accurate in selecting the optimal method by evaluating methods in a second layer of missingness simulation. All source files for the simulation and the real data analyses are available on the author's publication website

The Noncommutative Harmonic Oscillator based in Simplectic Representation of Galilei Group

In this work we study symplectic unitary representations for the Galilei group. As a consequence the Schr\"odinger equation is derived in phase space. The formalism is based on the non-commutative structure of the star-product, and using the group theory approach as a guide a physical consistent theory in phase space is constructed. The state is described by a quasi-probability amplitude that is in association with the Wigner function. The 3D harmonic oscillator and the noncommutative oscillator are studied in phase space as an application, and the Wigner function associated to both cases are determined.Comment: 7 pages,no figure

Melasma and its association with different types of nevi in women: A case-control study

<p>Abstract</p> <p>Background</p> <p>Very little is known about possible association of nevi and melasma. The study objective was to determine if there is an association between melasma and existence of different kinds of nevi.</p> <p>Methods</p> <p>In a case-control study, 120 female melasma patients referred to dermatology clinic of Ardabil and 120 patients referred to other specialty clinics who lacked melasma were enrolled after matching for age. Number of different types of nevi including lentigines and melanocytic nevi were compared between case and control group patients. Data were entered into the computer and analyzed by SPSS 13 statistical software.</p> <p>Results</p> <p>Mean number of lentigines was 25.5 in melasma group compared to 8 in control group(P < 0.01). Mean number of melanocytic nevi was 13.2 in cases compared to 2.8 in control group(P < 0.001). Multivariate analysis showed that existence of freckles, lentigines and more than three melanocytic nevi were positively related to developing melasma. The chance of melasma increased up to 23 times for patients having more than three melanocytic nevi. Congenital nevi were observed among 10% both in case and control groups. Campbell de morgan angiomas were seen among 26 patients(21.8%) in case group compared to 6 patients(5%) in control group.</p> <p>Conclusion</p> <p>Existence of lentigines and melanocytic nevi increases chance of having melasma</p

Flow of red blood cells suspensions through hyperbolic microcontractions

The present study uses a hyperbolic microchannel with a low aspect ratio (AR) to investigate how the red blood cells (RBCs) deform under conditions of both extensional and shear induced flows. The deformability is presented by the degree of the deformation index (DI) of the flowing RBCs throughout the microchannel at its centerline. A suitable image analysis technique is used for semi-automatic measurements of average DIs, velocity and strain rate of the RBCs travelling in the regions of interest. The results reveal a strong deformation of RBCs under both extensional and shear stress dominated flow conditions

Effects of an irregular bedtime schedule on sleep quality, daytime sleepiness, and fatigue among university students in Taiwan

<p>Abstract</p> <p>Background</p> <p>An irregular bedtime schedule is a prevalent problem in young adults, and could be a factor detrimentally affecting sleep quality. The goal of the present study was to explore the association between an irregular bedtime schedule and sleep quality, daytime sleepiness, and fatigue among undergraduate students in Taiwan.</p> <p>Methods</p> <p>A total of 160 students underwent a semi-structured interview and completed a survey comprising 4 parts: Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and a rating of irregular bedtime frequency. Participants were grouped into 3 groups in terms of irregular bedtime frequency: low, intermediate, or high according to their 2-week sleep log. To screen for psychological disorders or distress that may have affected responses on the sleep assessment measures, the Chinese health questionnaire-12 (CHQ-12) was also administered.</p> <p>Results</p> <p>We found an increase in bedtime schedule irregularity to be significantly associated with a decrease in average sleep time per day (Spearman r = -0.22, p = 0.05). Multivariate regression analysis revealed that irregular bedtime frequency and average sleep time per day were correlated with PSQI scores, but not with ESS or FSS scores. A significant positive correlation between irregular bedtime frequency and PSQI scores was evident in the intermediate (partial r = 0.18, p = 0.02) and high (partial r = 0.15, p = 0.05) frequency groups as compared to low frequency group.</p> <p>Conclusion</p> <p>The results of our study suggest a high prevalence of both an irregular bedtime schedule and insufficient sleep among university students in Taiwan. Students with an irregular bedtime schedule may experience poor sleep quality. We suggest further research that explores the mechanisms involved in an irregular bedtime schedule and the effectiveness of interventions for improving this condition.</p

Optimization of an Electron Transport Layer to Enhance the Power Conversion Efficiency of Flexible Inverted Organic Solar Cells

The photovoltaic (PV) performance of flexible inverted organic solar cells (IOSCs) with an active layer consisting of a blend of poly(3-hexylthiophene) and [6, 6]-phenyl C61-butlyric acid methyl ester was investigated by varying the thicknesses of ZnO seed layers and introducing ZnO nanorods (NRs). A ZnO seed layer or ZnO NRs grown on the seed layer were used as an electron transport layer and pathway to optimize PV performance. ZnO seed layers were deposited using spin coating at 3,000 rpm for 30 s onto indium tin oxide (ITO)-coated polyethersulphone (PES) substrates. The ZnO NRs were grown using an aqueous solution method at a low temperature (90°C). The optimized device with ZnO NRs exhibited a threefold increase in PV performance compared with that of a device consisting of a ZnO seed layer without ZnO NRs. Flexible IOSCs fabricated using ZnO NRs with improved PV performance may pave the way for the development of PV devices with larger interface areas for effective exciton dissociation and continuous carrier transport paths

A Fluorescence-Based High-Throughput Assay for the Discovery of Exchange Protein Directly Activated by Cyclic AMP (EPAC) Antagonists

Background: The discovery, more than ten years ago, of exchange proteins directly activated by cAMP (EPAC) as a new family of intracellular cAMP receptors revolutionized the cAMP signaling research field. Extensive studies have revealed that the cAMP signaling network is much more complex and dynamic as many cAMP-related cellular processes, previously thought to be controlled by protein kinase A, are found to be also mediated by EPAC proteins. Although there have been many important discoveries in the roles of EPACs greater understanding of their physiological function in cAMP-mediated signaling is impeded by the absence of EPAC-specific antagonist. Methodology/Principal Findings: To overcome this deficit, we have developed a fluorescence-based high throughput assay for screening EPAC specific antagonists. Our assay is highly reproducible and simple to perform using the ‘‘mix and measure’ ’ format. A pilot screening using the NCI-DTP diversity set library led to the identification of small chemical compounds capable of specifically inhibiting cAMP-induced EPAC activation while not affecting PKA activity. Conclusions/Significance: Our study establishes a robust high throughput screening assay that can be effectively applied for the discovery of EPAC-specific antagonists, which may provide valuable pharmacological tools for elucidating th