bluuebunny/crossref_metadata_2025 huggingface dataset:
Origin of fine oscillations in the photoluminescence spectrum of 2-dimensional electron gas formed in AlGaN/GaN high electron mobility transistor structures
Authors: Jana Dipankar , Porwal S. , Jain Anubha , Oak S. M. , Sharma T. K.
Published: November 2015

An unambiguous identification of the fine oscillations observed in the low temperature photoluminescence (PL) spectra of AlGaN/GaN based high electron mobility transistor (HEMT) structures is carried out. In literature, such oscillations have been erroneously identified as the sub-levels of 2-dimensional electron gas (2DEG) formed at AlGaN/GaN heterointerface. Here, the origin of these oscillations is probed by performing the angle dependent PL and reflectivity measurements under identical conditions. Contrary to the reports available in literature, we find that the fine oscillations are not related to 2DEG sub-levels. The optical characteristics of these oscillations are mainly governed by an interference phenomenon. In particular, peculiar temperature dependent redshift and excitation intensity dependent blueshift, which have been interpreted as the characteristics of 2DEG sub-levels in HEMT structures by other researchers, are understood by invoking the wavelength and temperature dependence of the refractive index of GaN within the framework of interference phenomenon. The results of other researchers are also consistently explained by considering the fine oscillatory features as the interference oscillations.
Estimation and uncertainty of reversible Markov models
Authors: Trendelkamp-Schroer Benjamin , Wu Hao , Paul Fabian , Noé Frank
Published: November 2015

Reversibility is a key concept in Markov models and master-equation models of molecular kinetics. The analysis and interpretation of the transition matrix encoding the kinetic properties of the model rely heavily on the reversibility property. The estimation of a reversible transition matrix from simulation data is, therefore, crucial to the successful application of the previously developed theory. In this work, we discuss methods for the maximum likelihood estimation of transition matrices from finite simulation data and present a new algorithm for the estimation if reversibility with respect to a given stationary vector is desired. We also develop new methods for the Bayesian posterior inference of reversible transition matrices with and without given stationary vector taking into account the need for a suitable prior distribution preserving the meta-stable features of the observed process during posterior inference. All algorithms here are implemented in the PyEMMA software — http://pyemma.org — as of version 2.0.
New insights on the propagation of pulsed atmospheric plasma streams: From single jet to multi jet arrays
Authors: Robert E. , Darny T. , Dozias S. , Iseni S. , Pouvesle J. M.
Published: November 2015

Atmospheric pressure plasma propagation inside long dielectric tubes is analyzed for the first time through nonintrusive and nonperturbative time resolved bi-directional electric field (EF) measurements. This study unveils that plasma propagation occurs in a region where longitudinal EF exists ahead the ionization front position usually revealed from plasma emission with ICCD measurement. The ionization front propagation induces the sudden rise of a radial EF component. Both of these EF components have an amplitude of several kV/cm for helium or neon plasmas and are preserved almost constant along a few tens of cm inside a capillary. All these experimental measurements are in excellent agreement with previous model calculations. The key roles of the voltage pulse polarity and of the target nature on the helium flow patterns when plasma jet is emerging in ambient air are documented from Schlieren visualization. The second part of this work is then dedicated to the development of multi jet systems, using two different setups, based on a single plasma source. Plasma splitting in dielectric tubes drilled with sub millimetric orifices, but also plasma transfer across metallic tubes equipped with such orifices are reported and analyzed from ICCD imaging and time resolved EF measurements. This allows for the design and the feasibility validation of plasma jet arrays but also emphasizes the necessity to account for voltage pulse polarity, target potential status, consecutive helium flow modulation, and electrostatic influence between the produced secondary jets.
Role of excited state solvent fluctuations on time-dependent fluorescence Stokes shift
Authors: Li Tanping , Kumar Revati
Published: November 2015

We explore the connection between the solvation dynamics of a chromophore upon photon excitation and equilibrium fluctuations of the solvent. Using molecular dynamics simulations, fluorescence Stokes shift for the tryptophan in Staphylococcus nuclease was examined using both nonequilibrium calculations and linear response theory. When the perturbed and unperturbed surfaces exhibit different solvent equilibrium fluctuations, the linear response approach on the former surface shows agreement with the nonequilibrium process. This agreement is excellent when the perturbed surface exhibits Gaussian statistics and qualitative in the case of an isomerization induced non-Gaussian statistics. However, the linear response theory on the unperturbed surface breaks down even in the presence of Gaussian fluctuations. Experiments also provide evidence of the connection between the excited state solvent fluctuations and the total fluorescence shift. These observations indicate that the equilibrium statistics on the excited state surface characterize the relaxation dynamics of the fluorescence Stokes shift. Our studies specifically analyze the Gaussian fluctuations of the solvent in the complex protein environment and further confirm the role of solvent fluctuations on the excited state surface. The results are consistent with previous investigations, found in the literature, of solutes dissolved in liquids.
Heavy rare-gas atomic pairs and the “double penalty” issue: Isotropic Raman lineshapes by Kr2, Xe2, and KrXe at room temperature
Authors: Chrysos M. , Rachet F.
Published: November 2015

We report absolutely calibrated isotropic Raman lineshapes for Kr2 and Xe2 and for KrXe at 294.5 K and compare them to quantum-mechanically generated lineshapes by using state-of-the-art second-order Møller-Plesset and DFT/B3LYP data sets for the induced mean dipole polarizability ᾱ. A very good agreement between the numerical and the experimental data was observed but the large uncertainty margins and the short Raman frequency interval probed in our experiment prevented us from rating on a more refined scale the performance of the tested ᾱ models. These drawbacks are inherent in isotropic Raman spectrum measurements and amplified for dissimilar pairs because, for such systems and spectra, the unreliable operation of subtracting optical signals of comparable magnitude occurs twice per Raman frequency shift value, thus penalizing twice the quality of the measured data. In light of our findings and of previously reported evidence about related electric properties in Kr2 and Xe2 and in KrXe, we are left with no doubt as to the consistency of the induced-polarizability and interatomic-potential data used for these three systems at the reported level of accuracy.
Intriguing structures and magic sizes of heavy noble metal nanoclusters around size 55 governed by relativistic effect and covalent bonding
Authors: Zhao X. J. , Xue X. L. , Guo Z. X. , Jia Yu , Li S. F. , Zhang Zhenyu , Gao Y. F.
Published: November 2015

Nanoclusters usually display exotic physical and chemical properties due to their intriguing geometric structures in contrast to their bulk counterparts. By means of first-principles calculations within density functional theory, we find that heavy noble metal PtN nanoclusters around the size N = 55 begin to prefer an open configuration, rather than previously reported close-packed icosahedron or core-shell structures. Particularly, for PtN, the widely supposed icosahedronal magic cluster is changed to a three-atomic-layered structure with D6h symmetry, which can be well addressed by our recently established generalized Wulff construction principle (GWCP). However, the magic number of PtN clusters around 55 is shifted to a new odd number of 57. The high symmetric three-layered Pt57 motif is mainly stabilized by the enhanced covalent bonding contributed by both spin-orbital coupling effect and the open d orbital (5d96s1) of Pt, which result in a delicate balance between the enhanced Pt–Pt covalent bonding of the interlayers and negligible d dangling bonds on the cluster edges. These findings about PtN clusters are also applicable to IrN clusters, but qualitatively different from their earlier neighboring element Os and their later neighboring element Au. The magic numbers for Os and Au are even, being 56 and 58, respectively. The findings of the new odd magic number 57 are the important supplementary of the recently established GWCP.
A modular reactor design for in situ synchrotron x-ray investigation of atomic layer deposition processes
Authors: Klug Jeffrey A. , Weimer Matthew S. , Emery Jonathan D. , Yanguas-Gil Angel , Seifert Sönke , Schlepütz Christian M. , Martinson Alex B. F. , Elam Jeffrey W. , Hock Adam S. , Proslier Thomas
Published: November 2015

Synchrotron characterization techniques provide some of the most powerful tools for the study of film structure and chemistry. The brilliance and tunability of the Advanced Photon Source allow access to scattering and spectroscopic techniques unavailable with in-house laboratory setups and provide the opportunity to probe various atomic layer deposition (ALD) processes in situ starting at the very first deposition cycle. Here, we present the design and implementation of a portable ALD instrument which possesses a modular reactor scheme that enables simple experimental switchover between various beamlines and characterization techniques. As first examples, we present in situ results for (1) X-ray surface scattering and reflectivity measurements of epitaxial ZnO ALD on sapphire, (2) grazing-incidence small angle scattering of MnO nucleation on silicon, and (3) grazing-incidence X-ray absorption spectroscopy of nucleation-regime Er2O3 ALD on amorphous ALD alumina and single crystalline sapphire.
Ion angle distribution measurement with a planar retarding field analyzer
Authors: Sharma Shailesh , Gahan David , Scullin Paul , Daniels Stephen , Hopkins M. B.
Published: November 2015

A new technique is presented to measure the angular distribution of plasma ions bombarding the substrate surface with a planar retarding field analyzer. By varying the effective aspect ratio of the analyzer’s aperture, ions with different angular spread that are allowed through the device for detection are controlled. The analytical theory developed to define the ion current as a function of incident ion angle, ion energy, aperture geometry, and aspect ratio is shown. The method used to vary the effective aspect ratio of the aperture is also discussed. The mathematical theory is derived and the numerical solution discussed. Ion energy distributions, as a function of ion angle, with resolution as low as 3° can be measured.
Type II InAs/GaAsSb quantum dots: Highly tunable exciton geometry and topology
Authors: Llorens J. M. , Wewior L. , Cardozo de Oliveira E. R. , Ulloa J. M. , Utrilla A. D. , Guzmán A. , Hierro A. , Alén B.
Published: November 2015

External control over the electron and hole wavefunctions geometry and topology is investigated in a p-i-n diode embedding a dot-in-a-well InAs/GaAsSb quantum structure with type II band alignment. We find highly tunable exciton dipole moments and largely decoupled exciton recombination and ionization dynamics. We also predicted a bias regime where the hole wavefunction topology changes continuously from quantum dot-like to quantum ring-like as a function of the external bias. All these properties have great potential in advanced electro-optical applications and in the investigation of fundamental spin-orbit phenomena.
Multimode analysis of highly tunable, quantum cascade powered, circular graphene spaser
Authors: Jayasekara Charith , Premaratne Malin , Stockman Mark I. , Gunapala Sarath D.
Published: November 2015

We carried out a detailed analysis of a circular graphene spaser made of a circular graphene flake and a quantum cascade well structure. Owing to unique properties of graphene and quantum cascade well structure, the proposed design shows high mechanical and thermal stability and low optical losses. Additionally, operation characteristics of the model are analysed and tunability of the device is demonstrated. Some advantages of the proposed design include compact size, lower power operation, and the ability to set the operating wavelength over a wide range from Mid-IR to Near-IR. Thus, it can have wide spread applications including designing of ultracompact and ultrafast devices, nanoscopy and biomedical applications.
Photo-induced refractive index and topographical surface gratings in functionalized nanocarbon solid film
Authors: McGee David J. , Ferrie John , Plachy Aljoscha , Joo Yongho , Choi Jonathan , Kanimozhi Catherine , Gopalan Padma
Published: November 2015

We demonstrate that a single-walled carbon nanotube network noncovalently coupled with a pyrene-modified azo-benzene chromophore functions as a host matrix for a broad range of photo-orientation and photomechanical effects. The chromophore could be efficiently reoriented through repeated trans-cis-trans isomerization under linearly polarized 480 nm light, with Δn of 0.012 at 650 nm and fast characteristic rise-times of 0.12 s. Erasable phase diffraction gratings could also be written, with permanent surface relief gratings forming at sufficiently long irradiation times. In addition to demonstrating a mechanism for photo-manipulation of single-walled carbon nanotubes, these results show photo-orientation of chromophores in azo-functionalized single-walled carbon nanotube networks as a path towards the photosensitive tuning of the electrostatic environment of the nanotube.
Gyro-viscosity and linear dispersion relations in pair-ion magnetized plasmas
Authors: Kono M. , Vranjes J.
Published: November 2015

A fluid theory has been developed by taking account of gyro-viscosity to study wave propagation characteristics in a homogeneous pair-ion magnetized plasma with a cylindrical symmetry. The exact dispersion relations derived by the Hankel-Fourier transformation are shown comparable with those observed in the experiment by Oohara and co-workers. The gyro-viscosity is responsible for the change in propagation characteristics of the ion cyclotron wave from forward to backward by suppressing the effect of the thermal pressure which normally causes the forward nature of dispersion. Although the experiment has been already explained by a kinetic theory by the present authors, the kinetic derivations are so involved because of exact particle orbits in phase space, finite Lamor radius effects, and higher order ion cyclotron resonances. The present fluid theory provides a simple and transparent structure to the dispersion relations since the gyro-viscosity is renormalized into the ion cyclotron frequency which itself indicates the backward nature of dispersion. The usual disadvantage of a fluid theory, which treats only fundamental modes of eigen-waves excited in a system and is not able to describe higher harmonics that a kinetic theory does, is compensated by simple derivations and clear picture based on the renormalization of the gyro-viscosity.
High performance CaS solar-blind ultraviolet photodiodes fabricated by seed-layer-assisted growth
Authors: He Qing Lin , Lai Ying Hoi , Liu Yi , Beltjens Emeline , Qi Jie , Sou Iam Keong
Published: November 2015

CaS, with a direct bandgap of 5.38 eV, is expected to be a strong candidate as the active-layer of high performance solar-blind UV photodiodes that have important applications in both civilian and military sectors. Here, we report that a seed-layer-assisted growth approach via molecular beam epitaxy can result in high crystalline quality rocksalt CaS thin films on zincblende GaAs substrates. The Au/CaS/GaAs solar-blind photodiodes demonstrated , more than five orders in its visible rejection power, a photoresponse of 36.8 mA/w at zero bias and a corresponding quantum efficiency as high as 19% at 235 nm.
Electric field-induced softening of alkali silicate glasses
Authors: McLaren C. , Heffner W. , Tessarollo R. , Raj R. , Jain H.
Published: November 2015

Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.
Resonant and time-resolved spin noise spectroscopy
Authors: Pursley Brennan C. , Song X. , Sih V.
Published: November 2015

We demonstrate a method to extend the range of pulsed laser spin noise measurements to long spin lifetimes. We use an analog detection scheme with a bandwidth limited only by laser pulse duration. Our model uses statistics and Bloch-Torrey equations to extract the Lande g-factor, Faraday cross-section σF, and spin lifetime τs, while accounting for finite detector response. Varying the magnetic field with a fixed probe-probe delay yields τs when it is longer than the laser repetition period. Varying the probe-probe delay with a fixed field produces a time-domain measurement of the correlation function.
Giant enhancement of the third harmonic in graphene integrated in a layered structure
Authors: Savostianova N. A. , Mikhailov S. A.
Published: November 2015

Graphene was shown to have strongly nonlinear electrodynamic properties. In particular, being irradiated by an electromagnetic wave with the frequency ω, it can efficiently generate higher frequency harmonics. Here, we predict that in a specially designed structure “graphene— dielectric—metal” the third-harmonic (3ω) intensity can be increased by more than two orders of magnitude as compared to an isolated graphene layer.
Three-axis atomic magnetometer based on spin precession modulation
Authors: Huang H. C. , Dong H. F. , Hu X. Y. , Chen L. , Gao Y.
Published: November 2015

We demonstrate a three-axis atomic magnetometer with one intensity-modulated pump beam and one orthogonal probe beam. The main field component is measured using the resonance of the pumping light, while the transverse field components are measured simultaneously using the optical rotation of the probe beam modulated by the spin precession. It is an all-optical magnetometer without using any modulation field or radio frequency field. Magnetic field sensitivity of 0.8 pT/Hz1∕2 is achieved under a bias field of 2 μT.
Using magnetic nanoparticles to probe protein damage in ferritin caused by freeze concentration
Authors: Chagas E. F. , Correia Carreira S. , Schwarzacher W.
Published: November 2015

We demonstrate a method for monitoring the damage caused to a protein during freeze-thawing in the presence of glycerol, a cryo-protectant. For this work we synthesized magnetite nanoparticles doped with 2.5% cobalt inside the protein ferritin (CMF), dissolved them in different concentration glycerol solutions and measured their magnetization after freezing in a high applied field (5 T). As the temperature was raised, a step-like decrease in the sample magnetization was observed, corresponding to the onset of Brownian relaxation as the viscosity of the freeze-concentrated glycerol solution decreased. The position of the step reveals changes to the protein hydrodynamic radius that we attribute to protein unfolding, while its height depends on how much protein is trapped by ice during freeze concentration. Changes to the protein hydrodynamic radius are confirmed by dynamic light scattering (DLS) measurements, but unlike DLS, the magnetic measurements can provide hydrodynamic data while the solution remains mainly frozen.
Bilayer avalanche spin-diode logic
Authors: Friedman Joseph S. , Fadel Eric R. , Wessels Bruce W. , Querlioz Damien , Sahakian Alan V.
Published: November 2015

A novel spintronic computing paradigm is proposed and analyzed in which InSb p-n bilayer avalanche spin-diodes are cascaded to efficiently perform complex logic operations. This spin-diode logic family uses control wires to generate magnetic fields that modulate the resistance of the spin-diodes, and currents through these devices control the resistance of cascaded devices. Electromagnetic simulations are performed to demonstrate the cascading mechanism, and guidelines are provided for the development of this innovative computing technology. This cascading scheme permits compact logic circuits with switching speeds determined by electromagnetic wave propagation rather than electron motion, enabling high-performance spintronic computing.
Effects of magnetic field treatment on dielectric properties of CCTO@Ni/PVDF composite with low concentration of ceramic fillers
Authors: Chi Q. G. , Gao L. , Wang X. , Chen Y. , Dong J. F. , Cui Y. , Lei Q. Q.
Published: November 2015

Using melt mixing, we produced a ceramic/polymer composite with a matrix of polyvinylidene fluoride (PVDF) and a filler of 5 vol.% Ni-deposited CaCu3Ti4O12 core-shell ceramic particles (CCTO@Ni), and studied its prominent dielectric characteristics for the first. Its phase composition and morphology were analyzed by X-ray diffraction and scanning electron microscopy, respectively. After treating the composite films with various durations of a magnetic field treatment, we compared their dielectric properties. We found that the CCTO@Ni ceramic had a typical urchin-like core-shell structure, and that different durations of the magnetic field treatment produced different distributions of ceramic particles in the PVDF matrix. The dielectric permittivity of the untreated CCTO@Ni/PVDF composite was 20% higher than that of neat PVDF, and it had a low loss tangent. However, only the composite treated for 30 min in the magnetic field had an ultra-high dielectric permittivity of 1.41 × 104 at 10 Hz, three orders of magnitude higher than the untreated composite, which declined dramatically with increasing frequency, accompanied by an insulating-conducting phase transition and an increase in loss tangent. Our results demonstrate that changes in the dielectric properties of PVDF composites with magnetic field treatment are closely related to the percolation effect and interfacial polarization.
Differences in seedling water-stress response of two co-occurring Banksia species
Authors: Holloway-Phillips M. M. , Huai H. , Cochrane A. , Nicotra A. B.
Published: November 2015

In the South-west Australian Floristic Region, timing of rainfall is critical for successful seedling establishment, as is surviving the first year’s summer drought for population persistence. Predictions of a warmer, drier future, therefore, threaten the persistence of obligate seeding species. Here, we investigate the drought tolerance of two co-occurring Banksia (Proteaceae) species by withholding water in pots to different extents of soil drying. Seed was collected from high- and low-rainfall populations, to test for niche differentiation in water-use strategies at the species level, as well as population differentiation. On the basis of a more negative leaf water potential at minimal levels of stomatal conductance and quantum yield, B. coccinea was considered to be more drought tolerant than B. baxteri. This was supported at the anatomical level according to xylem-vessel attributes, with a higher estimated collapse pressure suggesting that B. coccinea is less vulnerable to xylem cavitation. Population contrasts were observed mainly for B. baxteri, with a lower leaf-expansion increment rate in the low-rainfall population providing for drought avoidance, which was reflected in a higher rate of survival than with the high-rainfall population in which 87.5% of plants showed complete leaf senescence. The implications of species differences in water-use strategies are that community dynamics may start to shift as the climate changes. Importantly, this shift may be population dependent. A systematic understanding of adaptive capacity will help inform the choice of population for use in revegetation programs, which may lead to increased resilience and persistence in the face of environmental change. The results of the present study suggest that should declines in B. baxteri populations be noted, revegetating with seed collected from the low-rainfall population may help improve the chances of this species surviving into the future.
Assessment of N‐Terminal Prohormone B‐Type Natriuretic Peptide as a Measure of Vascular and Ventricular Function in Pediatric Pulmonary Arterial Hypertension
Authors: Kheyfets Vitaly O. , Dunning Jamie , Truong Uyen , Ivy D. Dunbar , Hunter Kendall A. , Shandas Robin
Published: November 2015

Pulmonary arterial hypertension (PAH) is a progressive disease that puts excessive mechanical loads on the ventricle due to a gradual increase in pulmonary vascular impedance. We hypothesize that the increase in right ventricular (RV) afterload is reflected in the concentration of circulating biochemical markers of ventricular strain and stress (B‐type natriuretic peptide [BNP] and N‐terminal prohormone BNP [NT‐proBNP]). We retrospectively analyzed right heart catheterization (RHC) and serum biochemical analysis data (n = 56) for a pediatric PAH cohort with no sign of left ventricular dysfunction. Using RHC data, we computed an estimate of pulmonary vascular resistance (PVR), compliance, and ventricular‐vascular coupling. We also compared how the early onset of interventricular decoupling (characterized as septal flattening) impacts serum NT‐proBNP concentrations. Our data revealed correlated NT‐proBNP expression with both the resistive and reactive components of RV afterload, an estimate of ventricular‐vascular coupling, and a significant increase in biomarker expression in patients with a flattened interventricular septum. Furthermore, the strong correlation between PVR and NT‐proBNP appears to break down under flat septum morphology. Over 80% of resistive RV afterload variance is reflected in serum NT‐proBNP concentration in pediatric patients with PAH with no sign of left ventricular dysfunction. Reactive afterload appears to contribute to myocardial NT‐proBNP release at advanced stages of PAH. Therefore, in mild‐to‐moderate PAH, resistive afterload is likely the greatest contributor to RV wall stress. These findings could also be used to estimate invasive RHC measurements from serum biochemical analysis, but more work is needed to improve correlations and overcome the issue of interventricular decoupling.
Image Artifacts
Authors: DePuey E. Gordon
Published: November 2015

Artifacts and normal variants are a significant source of false-positive interpretations of myocardial perfusion single-photon emission computed tomography (SPECT). This chapter discusses how, by anticipating and recognizing such findings, the astute technologist and interpreting physician can increase test specificity in the diagnosis of coronary artery disease and avoid unnecessary catheterization of normal patients.
Role of Imaging in Diabetes Mellitus
Authors: Cuocolo Alberto , Zampella Emilia
Published: November 2015

Although there has been a marked decline in mortality due to coronary artery disease (CAD) in the overall population in the past three decades, reducing CAD mortality in patients with diabetes mellitus (DM) has proven exceptionally difficult. Several epidemiological studies have shown that DM is associated with a marked increase in the risk of CAD. The symptoms are not a reliable means of identifying patients at higher risk considering that angina is threefold less common in DM than in non-DM. Noninvasive cardiac imaging, such as echocardiography, nuclear cardiology, computed tomography, and magnetic resonance imaging, can provide insight into different aspects of the disease process, from imaging at the cellular level to microvascular and endothelial dysfunction, autonomic neuropathy, coronary atherosclerosis, and interstitial fibrosis with scar formation. In particular, stress myocardial perfusion imaging has taken a central role in the diagnosis, evaluation, and management of CAD in DM patients.
Cardiovascular Molecular Imaging
Authors: Morrison Alan R. , Wu Joseph C. , Sadeghi Mehran M.
Published: November 2015

Cardiovascular molecular imaging is a relatively young but rapidly expanding discipline that consists of a biologically-targeted approach to the assessment of physiologic and pathologic processes in vivo. This novel approach to imaging involves the integration of multiple disciplines such as cell and molecular biology, chemistry, and imaging sciences. The ultimate goal is quantitative assessment of cardiovascular processes at the cellular and molecular level, moving beyond traditional diagnostic information, in order to guide individually tailored therapy. In fact, it is likely that specific approaches to molecular imaging will be developed in tandem with the development of novel therapeutic strategies. Recent advances in probe development and imaging systems have contributed to evolution of molecular imaging toward clinical translational. These include technological progress in traditional imaging platforms; along with the emergence of newer imaging modalities such as photoacoustic imaging. In addition, hybrid imaging (e.g. nuclear imaging with CT or MRI) has the potential for improved spatial localization, and more accurate quantification by coupling anatomic and biological information. In addition to potential clinical applications that address existing diagnostic gaps in cardiovascular medicine, molecular imaging allows for unique approaches to studying pathophysiology. This chapter is intended to provide an overview of the state of the art in cardiovascular molecular imaging, highlighting how it may improve the management of major cardiovascular diseases.
Use of Artificial Intelligence Including Decision Support Systems in Cardiac Imaging
Authors: Garcia Ernest V.
Published: November 2015

Artificial intelligence methods, including clinical decision support systems will continue to evolve with, and adapt to, nuclear cardiology and the changing needs of physicians in specific, and to nuclear medicine technology and the health care system in general. The high level of automation already achieved in myocardial perfusion imaging is unmatched by any other cardiac imaging modality, and continues to be its major strength. In addition, strong statistical evaluations of the accuracy and validity of the various techniques have been made possible simply because of the large amount of objectivity and standardization in the automated processes. These strengths when applied to decision support systems that are affordable and easily accessible should allow most nuclear cardiology physicians to perform at a high level of expertise when interpreting imaging studies to demonstrate the value of nuclear cardiology in patient management, and most importantly, to maintain the highest quality clinical care.
Physician Certification and Lab Accreditation
Authors: Van Decker William A.
Published: November 2015

Physician Certification and Lab Accreditation in Nuclear Cardiology are two key cornerstones of the Quality Program of this medical field. The ability and privilege to handle Isotopes for medical use is regulated by NRC with federal laws on training and experience (10CFR 35) incorporated into clinical training guidelines. Core Cardiology Training Symposium (COCATS) and documents sponsored (and updated) by the American College of Cardiology (ACC) specify the clinical training necessary to independently practice nuclear cardiology. Certification Board of Nuclear Cardiology (CBNC) collects appropriate prerequisite statements of training that match guidelines and administers a well- constructed examination leading to physician certification in recognition of meeting national standards to practice Nuclear Cardiology. Policies and procedures of NRC/COCATS/CBNC are reviewed in this chapter and near term challenges to evolving physician certification in a complex healthcare system are explored. Lab Accreditation is a quality process that goes beyond physicians to assess equipment, staff, policies and procedures, image quality, and reporting. Lab accreditation by one of three recognized accrediting bodies is now mandated for reimbursement of advanced imaging in Medicare program. Intersociety Accreditation Commission (IAC, Nuclear/PET division) is a recognized body for lab accreditation and has placed special emphasis on clinical reporting/outcomes and meaningful quality improvement activities. IAC Nuclear cardiology Standards are reviewed as opportunities to externally be recognized for meeting quality standards within a protected peer review climate. As with certification, near term challenges exist for evolving lab accreditation and these are explored as well in this chapter.
Epidemiology of kidney disease
Authors: Bello Aminu , Tonelli Marcello , Jager Kitty
Published: November 2015

Renal epidemiology has moved from a focus on patients treated with renal replacement therapy using data from renal registries, to a much broader view of acute and chronic kidney disease. A review of essential epidemiological concepts and principles is followed by discussion of the epidemiology of different types of kidney disease: acute kidney injury, chronic kidney disease, and end-stage renal disease. The chapter concludes with a section on future challenges and potential solutions.
Assessment of renal function
Authors: Speeckaert Marijn , Delanghe Jopis
Published: November 2015

Glomerular filtration rate (GFR) can be measured as the clearance of exogenous or endogenous filtration markers. Practical formulas permit estimation of creatinine clearance or GFR without timed urine collections in many stable patients with CKD. Standardization of serum creatinine is important for all of these estimation methods and implementing traceability of the assays to the new global SRM 967 standard has led to changes in clinical decision-making criteria. Calibration to an IDMS reference produces a lowering of serum creatinine values by 10–30% for most methods. Serum creatinine concentration depends on age, gender and muscle mass. Cystatin C is an alternative marker of GFR, but estimation is more expensive and it is not clear that it has a useful place in routine practice.
The MDRD Study equation was validated in the framework of the Modification of Diet in Renal Diseases study. It is superior to the Cockcroft and Gault formula for estimating Creatinine Clearance in most people. In 2009, the CKD Epidemiology Collaboration (CKD-EPI) formula was introduced, which provides a more accurate estimation for patients with GFR values between 60 and 90 mL/min. In children, the Schwartz formula is frequently used.
Some urinary markers of kidney disease are also discussed.
Immunological investigation of the patient with renal disease
Authors: Berden Jo H. M. , Wetzels Jack F. M.
Published: November 2015

Laboratory techniques (electrophoresis, indirect immunofluorescence, ELISA, and immunoblotting) required for immunological investigation of the patient with renal disease are described.
Renal disease-related aspects of immunoglobulins (immunoglobulin A, paraproteins, cryoglobulins), complement, antinuclear antibodies, anti-C1q antibodies, antineutrophil cytoplasmic antibodies, anti-glomerular basement membrane antibodies, antipodocyte antibodies, antiphospholipid antibodies, and antimicrobial responses (streptococci, hepatitis C, hepatitis B) are reviewed.
Laboratory assays which evaluate the immune response, in particular the identification of (auto)-antibodies are valuable tools in establishing a diagnosis and/or monitoring of the activity of the disease.
Guidelines are given for immunological studies in patients with specific renal syndromes including nephrotic syndrome, rapidly progressive glomerulonephritis, systemic lupus erythematosus, and thrombotic microangiopathy.
The renal biopsy
Authors: Roberts Ian S. D. , Mason Philip , Fogo Agnes B.
Published: November 2015

This chapter describes the indications for renal biopsy, the procedure, processing of the specimen and the diagnostic method applied by the nephropathologist, and illustrates the spectrum of pathologies seen. The terminology used in renal pathology is explained and illustrated. Diagnostic algorithms are presented. More detailed descriptions of the various pathologies, and in particular the rarer entities, are provided in specific chapters. The focus will be on native renal diseases.
The renal biopsy is an invasive procedure associated with a risk of serious complications. The decision to perform a biopsy is based on a careful risk: benefit assessment. The final diagnosis is usually derived from combining clinical and histological data; it is therefore essential that the nephrologist includes all relevant information on the pathology request form. Discussion of the biopsy findings at a multidisciplinary meeting is an important part of the diagnostic and management decision-making process.
The essential starting point for histological diagnosis is to define the morphological abnormality at light microscopy, the ‘pattern of disease’. In only a minority of cases will this be sufficient to provide a firm diagnosis; more frequently the morphology provides the basis for formulating a differential diagnosis.
Supplemental information from immunohistology and electron microscopy, in addition to clinical, biochemical, and serological data, are used to reach a precise diagnosis.
In addition to diagnosis, the renal biopsy may provide prognostic information and be used to guide therapy. For inflammatory renal diseases in particular, the biopsy report will include measures of disease activity and chronicity.
In some instances the diagnosis may already be clear, and the biopsy is performed for grading and staging purposes or to assist in decisions about treatment.
Magnesium homeostasis
Authors: Houillier Pascal
Published: November 2015

Magnesium is critically important in the process of energy release. Although most magnesium is stored outside the extracellular fluid compartment, the regulated concentration appears in blood. Urinary magnesium excretion can decrease rapidly to low values when magnesium entry rate into the extracellular fluid volume is low, which has several important implications: cell and bone magnesium do not play a major role in the defence of blood magnesium concentration; while a major role is played by the kidney and especially the renal tubule, which adapts to match the urinary magnesium excretion and net entry of magnesium into extracellular fluid.
In the kidney, magnesium is reabsorbed in the proximal tubule, the thick ascending limb of the loop of Henle (TALH), and the distal convoluted tubule (DCT). Magnesium absorption is mainly paracellular in the proximal tubule and TALH, whereas it is transcellular in the DCT.
The hormone(s) regulating renal magnesium transport and blood magnesium concentration are not fully understood. Renal tubular magnesium transport is altered by a number of hormones, mainly in the TALH and DCT. Parathyroid hormone, calcitonin, arginine vasopressin, ß-adrenergic agonists, and epidermal growth factor, all increase renal tubular magnesium reabsorption; in contrast, prostaglandin E2 decreases magnesium reabsorption.
Non-hormonal factors also influence magnesium reabsorption: it is decreased by high blood concentrations of calcium and magnesium, probably via the action of divalent cations on the calcium-sensing receptor; metabolic acidosis decreases, and metabolic alkalosis increases, renal magnesium reabsorption.
Approach to the patient with hypocalcaemia
Authors: Linglart Agnès , Lambert Anne-Sophie
Published: November 2015

Calcium homeostasis is maintained through a fine balance between calcium absorption, parathyroid hormone secretion and action, vitamin D production and action, cellular compartmentalization of calcium ions, and renal function. Although the extracellular calcium level does not vary with age, the maintenance of calcium faces the significant mineral requirement of skeletal growth and bone mass acquisition during childhood.
Acquired or genetic defects in any determinants of blood calcium (i.e. vitamin D, parathyroid hormone, calcium absorption, etc.) may manifest as hypocalcaemia, especially during childhood/adolescence. The discovery of hypocalcaemia in a patient should trigger two clinical responses: (1) therapy to restore the calcium level to normal and (2) investigations to determine the cause of hypo/hypercalcaemia.
The patient with haematuria
Authors: Neary John , Turner Neil
Published: November 2015

Haematuria is a common presenting feature of diseases of the kidney or the renal tract. It is also common in screening tests, single dipstick tests being positive in perhaps 5% of individuals. Age and whether the blood is visible (macroscopic) or non-visible (microscopic) impact largely on whether the explanation is likely to be broadly urological or nephrological. Origins are most commonly simple or urological.
Macroscopic bleeding is rare in renal disease, and urine colour is then usually more rather smoky than red except when there is very acute inflammation. The chief urological causes are neoplasia, infection, stones, and trauma. Some traditionally medical conditions may cause simple bleeding; examples include cystic kidney diseases, papillary necrosis and macro- or microvascular ischaemic lesions.
The major concern to nephrologists is that even non-visible haematuria may be a pointer to inflammatory or destructive glomerular processes. The presence of casts or dysmorphic red cells is a pointer to glomerular disease; more important in clinical practice are the three other key markers of renal disease: proteinuria, renal impairment in the absence of urinary tract obstruction, and hypertension.
In the general population, microscopic haematuria does associate with a long-term increased risk of end-stage renal failure, so after negative investigations, occasional long-term checks are indicated. The case for population screening for haematuria appears weak.
Nephrotic syndrome
Authors: Rajakrishna Premil , Cameron Stewart , Turner Neil
Published: November 2015

Nephrotic syndrome is the constellation of manifestations seen in patients with such severe proteinuria that serum albumin falls below normal levels. Its severity and the risk of complications are graded by the severity of the protein loss. The risks of some complications begin to rise at levels of proteinuria below those conventionally associated with nephrotic syndrome.
The main manifestation, oedema, is characterized by avid sodium retention and managed by sodium restriction and diuretics.
A pronounced thrombotic tendency is particularly apparent within the first 6 months of diagnosis and in patients with the most severe proteinuria. Venous thromboembolism may be a presenting feature. Prophylactic full anticoagulation may be considered for those at highest risk.
Hyperlipidaemia is severe and justifies lipid-lowering therapy in patients with sustained nephrotic syndrome.
There is a marked increased risk of bacterial infection, particularly from Streptococcus pneumoniae.
The causes of nephrotic syndrome are diseases affecting the podocyte, either directly or through an effect on glomerular matrix (e.g. through scarring). Identification of a cause is important for management and often requires a renal biopsy.
Antiglomerular basement membrane disease
Authors: Cui Zhao , Turner Neil , Zhao Ming-hui
Published: November 2015

Antiglomerular basement membrane disease is characteristically the most rapidly progressive (crescentic) nephritis. It is often accompanied by lung haemorrhage, and occasionally causes lung disease alone. Its hallmark is linear deposition of immunoglobulin G along the glomerular basement membrane. There are usually few systemic symptoms apart from any related to the lung disease. Urine shows haematuria, often macroscopic in very acute disease.
Membranoproliferative glomerulonephritis and C3 glomerulopathy
Authors: Gale Daniel P. , Cook Terry
Published: November 2015

Membranoproliferative glomerulonephritis (MPGN) is synonymous with mesangiocapillary glomerulonephritis and refers to light microscopic appearances of a kidney biopsy in which there are increased mesangial cells and matrix with thickening of the glomerular capillary walls, often with a double contour appearance. MPGN represents morphological appearances caused by a wide range of diseases, most of which are systemic and involve activation of the immune system.
It commonly presents as nephrotic syndrome, alternatively with proteinuria, haematuria, and varying degrees of hypertension and renal dysfunction.
MPGN was historically characterized into types 1–3 according to the location of immune deposits, but a more useful classification is by whether the underlying disorder results in prominent glomerular immunoglobulin deposition (with secondary complement deposited) or if there is glomerular complement, but scanty or no immunoglobulin deposited. The immunoglobulin group includes MPGN caused by infections, autoimmunity, cryoglobulinaemia, and paraprotein production. The complement group (C3 glomerulopathy) includes dense deposit disease and other complement disorders. Similar light microscopic appearances without deposition of immunoglobulin or complement are sometimes seen in patients with chronic thrombotic microangiopathies.
Management and prognosis depend on aetiology.
Acute tubulointerstitial nephritis
Authors: Baker Richard
Published: November 2015

Acute tubulointerstitial nephritis (ATIN) is an important cause of acute kidney injury which has a diverse aetiology but is most frequently caused by either an infection or drug reaction. Clinical features are usually non-specific or absent, although early accounts emphasized fever, rash, and eosinophilia. ATIN should be considered in all cases of acute kidney injury, especially when there is no obvious precipitant. If deemed clinically safe an early renal biopsy is recommended for diagnosis. Renal outcome will usually be good but in a significant minority, particularly the elderly, the outcome may be poor. There is evidence from a number of series that early treatment with corticosteroids leads to a more rapid and complete recovery of renal function.