On Exchange of Orbital Angular Momentum Between Twisted Photons and Atomic Electrons

We obtain an expression for the matrix element for a twisted (Laguerre-Gaussian profile) photon scattering from a hydrogen atom. We consider photons incoming with an orbital angular momentum (OAM) of $\ell \hbar$, carried by a factor of $e^{i \ell \phi}$ not present in a plane-wave or pure Gaussian profile beam. The nature of the transfer of $+2\ell$ units of OAM from the photon to the azimuthal atomic quantum number of the atom is investigated. We obtain simple formulae for these OAM flip transitions for elastic forward scattering of twisted photons when the photon wavelength $\lambda$ is large compared with the atomic target size $a$, and small compared the Rayleigh range $z_R$, which characterizes the collimation length of the twisted photon beam.Comment: 16 page

Gene therapy with Angiotensin-(1-9) preserves left ventricular systolic function after myocardial infarction

BACKGROUND: Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin angiotensin system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic minipump in mice. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI). OBJECTIVES: To evaluate effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post infarction. METHODS: C57BL/6 mice underwent permanent left anterior descending coronary artery ligation and cardiac function was assessed using echocardiography for 8 weeks followed by a terminal measurement of left ventricular (LV) pressure-volume loops. Ang-(1-9) was delivered by adeno-associated viral vector via single tail vein injection immediately following induction of MI. Direct effects of Ang-(1-9) on cardiomyocyte excitation–contraction coupling and cardiac contraction were evaluated in isolated mouse and human cardiomyocytes and in an ex vivo Langendorff perfused whole heart model. RESULTS: Gene delivery of Ang-(1-9) significantly reduced sudden cardiac death post-MI. Pressure–volume measurements revealed complete restoration of end systolic pressure, ejection fraction, end systolic volume and the end diastolic pressure–volume relationship by Ang-(1-9) treatment. Stroke volume and cardiac output were significantly increased versus sham. Histological analysis revealed only mild effects on cardiac hypertrophy and fibrosis, but a significant increase in scar thickness. Direct assessment of Ang-(1-9) on isolated cardiomyocytes demonstrated a positive inotropic effect via increasing calcium transient amplitude and increasing contractility. Ang-(1-9) increased contraction in the Langendorff model through a protein kinase A-dependent mechanism. CONCLUSIONS: Our novel findings show that Ang-(1-9) gene therapy preserves LV systolic function post-MI, restoring cardiac function. Furthermore, Ang-(1-9) has a direct effect on cardiomyocyte 3 calcium handling through a protein kinase A-dependent mechanism. These data highlight Ang-(1-9) gene therapy as a potential new strategy in the context of MI

THE PATIENT-SPECIFIC INJURY SCORE: PRECISION MEDICINE IN TRAUMA PATIENTS PREDICTS ORGAN DYSFUNCTION AND OUTCOMES

poster abstractIntroduction: Current injury scoring systems in polytraumatized patients are limited at predicting patient outcomes. We present a novel method that quantifies mechanical tissue damage and cumulative hypoperfusion using a precision medicine approach. We hypothesized that a Patient-Specific Injury score formulated from individualized injury indices would stratify patient risk for developing organ dysfunction after injury. We compared correspondence between PSI and the Injury Severity Score with outcomes of organ dysfunction and MOF. Methods: Fifty Multiply-injured-patients (MIPs) were studied. Tissue Damage Volume scores were measured from admission pan-axial CT scans using purpose-designed post-processing software to quantify volumetric magnitude and distribution of injuries. Ischemic injury was quantified using Shock Volumes. SV is a time-magnitude integration of shock index. Values above 0.9 were measured in the 24-hours after injury. Metabolic response was quantified by subtracting the lowest first 24 hr pH from 7.40. PSI combines these indices into the formula: PSI=[0.2TDV+SV]*MR. Correspondence coefficients from regression modeling between PSI and organ dysfunction, measured by the Marshall Multiple Organ Dysfunction score averaged from days 2-5 post-injury, were compared to similar regression models of ISS vs. day 2-5 MOD-scores. We compared PSI and ISS in patients that did or did not develop MOF. Results: PSI demonstrated better correlation to organ dysfunction (r2=0.576) in comparison to ISS (r2=0.393) using the MOD-score on days 2-5. Mean PSI increased 3.4x(58.5vs.17.0;p<0.02) and ISS scores increased 1.4x(39.0vs.28.0;p=0.10) in patients that developed MOF versus those that did not. Conclusions: This study shows that a precision medicine approach that integrates patient-specific indices of mechanical tissue damage, ischemic tissue injury, and metabolic response better corresponds to phenotypic changes including organ dysfunction and MOF compared to ISS in MIPs. The PSI-score can be calculated within 24 hours of injury, making it useful for stratifying risk and predicting the magnitude of organ dysfunction to anticipate

Electronic structure of sodium tungsten bronzes Na<SUB>x</SUB>WO<SUB>3</SUB> by high-resolution angle-resolved photoemission spectroscopy

The electronic structure of sodium tungsten bronzes, NaxWO3, for full range of x is investigated by high-resolution angle-resolved photoemission spectroscopy (HR-ARPES). The experimentally determined valence-band structure has been compared with the results of ab initio band-structure calculation. The HR-ARPES spectra taken in both the insulating and metallic phase of NaxWO3 reveal the origin of metal-insulator transition (MIT) in the sodium tungsten bronze system. In the insulating NaxWO3, the near-EF states are localized due to the strong disorder caused by the random distribution of Na+ ions in WO3 lattice. While the presence of an impurity band (level) induced by Na doping is often invoked to explain the insulating state found at low concentrations, there is no signature of impurity band (level) found from our results. Due to disorder and Anderson localization effect, there is a long-range Coulomb interaction of conduction electrons; as a result, the system is insulating. In the metallic regime, the states near EF are populated and the Fermi level shifts upward rigidly with increasing electron doping (x). The volume of electronlike Fermi surface (FS) at the &#915;(X) point gradually increases with increasing Na concentration due to W 5dt2g band filling. A rigid shift of EF is found to give a qualitatively good description of the FS evolution

Post-Prior discrepancies in CDW-EIS calculations for ion impact ionization fully differential cross sections

In this work we present fully differential cross sections (FDCSs) calculations using post and prior version of CDW--EIS theory for helium single ionization by 100 MeV C$^{6+}$ amu$^{-1}$ and 3.6 MeV amu$^{-1}$ Au$^{24+}$ and Au$^{53+}$ ions. We performed our calculations for different momentum transfer and ejected electron energies. The influence of internuclear potential on the ejected electron spectra is taken into account in all cases. We compare our calculations with absolute experimental measurements. It is shown that prior version calculations give better agreement with experiments in almost all studied cases.Comment: 9 pages, 7 figure

Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors

<p>Abstract</p> <p>Background</p> <p>The Fanconi anemia (FA) pathway is a multigene DNA damage response network implicated in the repair of DNA lesions that arise during replication or after exogenous DNA damage. The FA pathway displays synthetic lethal relationship with certain DNA repair genes such as <it>ATM </it>(Ataxia Telangectasia Mutated) that are frequently mutated in tumors. Thus, inhibition of FANCD2 monoubiquitylation (FANCD2-Ub), a key step in the FA pathway, might target tumor cells defective in ATM through synthetic lethal interaction. Curcumin was previously identified as a weak inhibitor of FANCD2-Ub. The aim of this study is to identify derivatives of curcumin with better activity and specificity.</p> <p>Results</p> <p>Using a replication-free assay in <it>Xenopus </it>extracts, we screened monoketone analogs of curcumin for inhibition of FANCD2-Ub and identified analog EF24 as a strong inhibitor. Mechanistic studies suggest that EF24 targets the FA pathway through inhibition of the NF-kB pathway kinase IKK. In HeLa cells, nanomolar concentrations of EF24 inhibited hydroxyurea (HU)-induced FANCD2-Ub and foci in a cell-cycle independent manner. Survival assays revealed that EF24 specifically sensitizes FA-competent cells to the DNA crosslinking agent mitomycin C (MMC). In addition, in contrast with curcumin, ATM-deficient cells are twofold more sensitive to EF24 than matched wild-type cells, consistent with a synthetic lethal effect between FA pathway inhibition and ATM deficiency. An independent screen identified 4H-TTD, a compound structurally related to EF24 that displays similar activity in egg extracts and in cells.</p> <p>Conclusions</p> <p>These results suggest that monoketone analogs of curcumin are potent inhibitors of the FA pathway and constitute a promising new class of targeted anticancer compounds.</p

The climate sensitivity of Norway spruce [Picea abies (L.) Karst.] in the southeastern European Alps

Tree ring chronologies were developed from trees growing at two sites in Slovenia which differed in their ecological and climatological characteristics. Ring width, maximum latewood density, annual height increment and latewood cellulose carbon isotope composition were developed at both sites and time-series verified against instrumental climate data over the period (AD 1960–AD 2002). Ring width sensitivity to summer temperature is site-dependent, with contrasting responses at alpine and lowland sites. Maximum density responds to September temperatures, suggesting lignification after cell division has ended for the season. Stable carbon isotopes have great potential, responding to summer temperature at oth alpine and lowland stands. Height increment appears relatively insensitive to climate, and is likely to be dominated by local stand dynamics

Inter-annual carbon isotope analysis of tree-rings by laser ablation

The stable carbon isotopic analysis of tree-rings for environmental, plant physiological and archaeological applications using conventional methods is occasionally limited by physical constraints (narrow rings) or administrative concerns (requirement for non-destructive sampling) that prevent researcher access to scientifically valuable wood samples. Analysis of such archives by laser-ablation can potentially address these issues and facilitate access to restricted archives. Smaller quantities of wood are required for analysis by laser ablation, hence the approach may be considered less-invasive and is virtually non-destructive compared to standard preparation methods. High levels of intra-annual isotopic variability reported elsewhere mean that a single measurement may not faithfully represent the inter-annual isotopic signal, so before such an approach can be used with confidence it is necessary to compare the stable carbon isotopic data produced using these two methods. This paper presents stable carbon isotope (δ13C) data from the resin-extracted wood of dated Scots Pine (Pinus sylvestris L.) tree-rings analysed using a modified Schulze-type laser-ablation system with results obtained using conventional manual sampling and analysis of α-cellulose prepared from the same tree-ring groups. The laser sampling system is found to perform very well against established more invasive methods. High correlations are observed between the methods for both raw and Suess corrected data (r > 0.90 n =50). These results highlight the potential for using laser-sampling to support the development of long isotope chronologies, for sampling narrow rings or for pre-screening cores prior to analysis using more detailed or labour intensive methods.201

In-situ metallic coating of atom probe specimen for enhanced yield, performance, and increased field-of-view

Atom probe tomography requires needle-shaped specimens with a diameter typically below 100 nm, making them both very fragile and reactive, and defects (notches at grain boundaries or precipitates) are known to affect the yield and data quality. The use of a conformal coating directly on the sharpened specimen has been proposed to increase yield and reduce background. However, to date, these coatings have been applied ex-situ and mostly are not uniformly. Here, we report on the controlled focused ion beam in-situ deposition of a thin metal film on specimens immediately after specimen preparation. Different metallic targets e.g. Cr were attached to a micromanipulator via a conventional lift-out method and sputtered using the Ga or Xe ions. We showcase the many advantages of coating specimens from metallic to non-metallic materials. We have identified an increase in data quality and yield, an improvement of the mass resolution, as well as an increase in the effective field-of-view enabling visualization of the entire original specimen, including the complete surface oxide layer. The ease of implementation of the approach makes it very attractive for generalizing its use across a very wide range of atom probe analyses