bluuebunny/crossref_metadata_2025 huggingface dataset:
Squeeze flow of a Carreau fluid during sphere impact
Authors: Uddin J. , Marston J. O. , Thoroddsen S. T.
Published: July 2012

We present results from a combined numerical and experimental investigation into the squeeze flow induced when a solid sphere impacts onto a thin, ultra-viscous film of non-Newtonian fluid. We examine both the sphere motion through the liquid as well as the fluid flow field in the region directly beneath the sphere during approach to a solid plate. In the experiments we use silicone oil as the model fluid, which is well-described by the Carreau model. We use high-speed imaging and particle tracking to achieve flow visualisation within the film itself and derive the corresponding velocity fields. We show that the radial velocity either diverges as the gap between the sphere and the wall diminishes (Ztip → 0) or that it reaches a maximum value and then decays rapidly to zero as the sphere comes to rest at a non-zero distance (Ztip = Zmin) away from the wall. The horizontal shear rate is calculated and is responsible for significant viscosity reduction during the approach of the sphere. Our model of this flow, based on lubrication theory, is solved numerically and compared to experimental trials. We show that our model is able to correctly describe the physical features of the flow observed in the experiments.
Global model of a gridded-ion thruster powered by a radiofrequency inductive coil
Authors: Chabert P. , Arancibia Monreal J. , Bredin J. , Popelier L. , Aanesland A.
Published: July 2012

A global (volume-averaged) model of a gridded-ion thruster is proposed. The neutral propellant (xenon gas) is injected into the thruster chamber at a fixed rate and a plasma is generated by circulating a radiofrequency current in an inductive coil. The ions generated in this plasma are accelerated out of the thruster by a pair of DC biased grids. The neutralization downstream is not treated. Xenon atoms also flow out of the thruster across the grids. The model, based on particle and energy balance equations, solves for four global variables in the thruster chamber: the plasma density, the electron temperature, the neutral gas (atom) density, and the neutral gas temperature. The important quantities to evaluate the thruster efficiency and performances are calculated from these variables and from the voltage across the grids. It is found that the mass utilization efficiency rapidly decreases with the gas flow rate. However, the radiofrequency power transfer efficiency increases significantly with the injected gas flow rate. Therefore, there is a compromise to be found between these two quantities.
Effect of solar intensity on efficiency of the convection solar air heater
Authors: Sekar M. , Sakthivel M. , Satheesh kumar S. , Ramesh C.
Published: July 2012

Solar radiation intercepted at the earth’s surface is of paramount importance for various applications, such as in the infrastructure and construction industry, estimation of crop productivity, environmental and agrometeogological research, atmospheric physics, and the practical utilization of renewable energy resources. Also, solar energy fuels the earth’s biosystem, drives the ocean and atmospheric currents and to a large extent dictates the regional climate. Solar drying refers to the method of using the sun’s energy for drying but excludes open air sun drying. The justification for solar driers is that more effective than sun drying but have lower operating cost than mechanized driers. Mechanized drying is faster than open air drying, uses much less land, and usually gives a better quality product. The equipment is expensive and requires substantial quantities of fuel or electricity to operate. The heat transfer characteristics and performance of the flat plate solar air heater with thermal storage are to be studied in this paper deals with the effect of the solar intensity.
New equipment for microwave electric field visualization
Authors: Karpov Igor A. , Shoo Egil D.
Published: July 2012

We present the operation and design of newly developed, fully automatic equipment for the visualization of microwave electric fields. This equipment enables the observation of microwave field patterns around different objects including metamaterial prototypes and to study the field patterns of various microwave antennas and other objects that have been developed and that interact with a surrounding microwave electromagnetic field. Moreover, the developed prototypes whose interaction with an incident electromagnetic wave is crucial for practical applications can be investigated using size scaling, and hence our equipment can be used for the testing of antennas and other devices that interact with electromagnetic radiation, not only at microwave frequencies, but also at radio frequencies. The performance of our innovative equipment was demonstrated through the investigation of the metamaterial cloak. The frequency behavior of the metamaterial cloak revealed frequency bands with maximum cloaking efficiencies.
Optical gain of two-dimensional hole gas by intersubband Raman transitions
Authors: Tsujino Soichiro
Published: July 2012

Raman gain of a two-dimensional hole gas is theoretically studied. It is shown that a finite gain is expected for a p-type quantum well without introducing asymmetry via a Raman transition between confined hole states. The gain and loss in SiGe and Ge quantum wells on Si substrates by hole intersubband transitions are modeled using an experimentally validated 6-band k·p method combined with a design of a SiGe ridge waveguide on Si substrate. A net modal gain of ∼20 cm−1 with the pump intensity of ∼4 MW cm−2 is predicted for a device with multiple square Ge quantum well active layers by the proposed intersubband Raman transition.
Mechanical stability of Ti6Al4V implant material after femtosecond laser irradiation
Authors: Symietz Christian , Lehmann Erhard , Gildenhaar Renate , Hackbarth Andreas , Berger Georg , Krüger Jörg
Published: July 2012

The surface of a titanium alloy (Ti6Al4V) implant material was covered with a bioactive calcium alkali phosphate ceramic with the aim to accelerate the healing and to form a stronger bond to living bone tissue. To fix the ceramic powder we used a femtosecond laser, which causes a thin surface melting of the metal. It is a requirement to prove that the laser irradiation would not reduce the lifetime of implants. Here we present the results of mechanical stability tests, determined by the rotating bending fatigue strength of sample rods. After describing the sample surfaces and their modifications caused by the laser treatment we give evidence for an unchanged mechanical stability. This applies not only to the ceramic fixation but also to a comparatively strong laser ablation.
Progress towards a high-gain and robust target design for heavy ion fusion
Authors: Henestroza Enrique , Grant Logan B.
Published: July 2012

Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an “X.” X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of ∼50 g/cm3 at peak compression, and fusion gains of ∼50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities ∼2 g/cm2 using two annular beams to implode the target to peak DT densities ∼100 g/cm3, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in ∼200 ps to start the burn propagation, obtaining gains of ∼300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh–Taylor (RT) and Richtmyer–Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning process. Also, preliminary HYDRA calculations, using a higher resolution mesh to study the shear flow of the DT fuel along the X-target walls, indicate that metal-mixed fuel produced near the walls would not be transferred to the DT ignition zone (at maximum ρR) located at the vertex of the X-target.
Realization of compressively strained GaN films grown on Si(110) substrates by inserting a thin AlN/GaN superlattice interlayer
Authors: Shen X. Q. , Takahashi T. , Kawashima H. , Ide T. , Shimizu M.
Published: July 2012

We investigate the strain properties of GaN films grown by plasma-assisted molecular beam epitaxy on Si(110) substrates. It is found that the strain of the GaN film can be converted from a tensile to a compressive state simply by inserting a thin AlN/GaN superlattice structure (SLs) within the GaN film. The GaN layers seperated by the SLs can have different strain states, which indicates that the SLs plays a key role in the strain modulation during the growth and the cooling down processes. Using this simple technique, we grow a crack-free GaN film exceeding 2-μm-thick. The realization of the compressively strained GaN film makes it possible to grow thick GaN films without crack generation on Si substrates for optic and electronic device applications.
Applicability of continuum absorption in semiconductor quantum wells to absolute absorption-strength standards
Authors: Yoshita Masahiro , Kamide Kenji , Suzuura Hidekatsu , Akiyama Hidefumi
Published: July 2012

The absolute strength of two-dimensional continuum absorption in semiconductor quantum wells (QWs) was investigated for application to an absorption-strength standard. We presented an equation for the continuum-state absorbance in a QW, showing that the absorbance near the band edge is essentially described by a universal value proportional to the fine-structure constant with correction terms for band-mixing effects and Coulomb enhancement effects. By using k·p equations with the established band parameters, we calculated the absorbance with quantitative estimations of the correction terms in typical semiconductor QWs. The results indicate that the absorbance of the QW is applicable to an absorption-strength standard.
Epitaxial Rh-doped SrTiO3 thin film photocathode for water splitting under visible light irradiation
Authors: Kawasaki S. , Nakatsuji K. , Yoshinobu J. , Komori F. , Takahashi R. , Lippmaa M. , Mase K. , Kudo A.
Published: July 2012

Epitaxial Rh-doped SrTiO3 thin film photocatalysts were fabricated by pulsed laser deposition under various deposition conditions. The oxygen pressure used during film growth was found to affect the valence of the Rh dopant in the Rh:SrTiO3 films, reproducing the known optical absorption behavior of powder samples. Evaporative Rh loss was observed at low growth pressures and high temperatures. Cyclic voltammetry measurements in a K2SO4 solution showed that Rh-doped SrTiO3 is a highly efficient hydrogen-producing photocathode with a characteristic p-type behavior under visible light irradiation.
Trimesic Acid-Based Star Mesogens with Flexible Spacer: Synthesis and Mesophase Characterization
Authors: Shanavas A. , Narasimhaswamy T. , Nasar A. Sultan
Published: July 2012

A series of trimesic acid-based star mesogens containing an octamethylenoxy spacer and two-ring containing side arms with terminal alkoxy groups were synthesised by a divergent approach. A structurally similar mesogen containing a three-ring side arm was also synthesised. All the mesogens and intermediates were characterised thoroughly using FT-IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis techniques. The mesophase characteristics were identified by hot stage optical polarising microscopy (HOPM) and differential scanning calorimetry (DSC), while X-ray was used to confirm the existence of a smectic A (SA) phase. The HOPM and DSC results revealed the presence of rich polymesomorphism in the star mesogens. The dominance of a SA phase in the series is attributed to the steric repulsion associated with steric asymmetry. The change of the side arm from two rings to three rings was found to increase the mesophase stability.
Modeling Photo-dissociation Dynamics of HBr+ by Vibrational Wave-packet Formalism
Authors: Mondal Chandan Kumar , Nath Bikram
Published: July 2012

Photo dissociation dynamics of diatomic molecular ion HBr+ interacting with ultra fast laser pulses of different envelop function has been presented both in zero and non zero temperature environment. The calculations pertain primarily to the ground electronic state of the molecular ion HBr+. The used potential of HBr+ is calibrated with the help of the ab initio theoretical calculation at the CCSD/6-311++G(3df, 2pd) level and then fitted with appropriate Morse parameters. The numerical bound states vibrational eigenvalues obtained by the time independent Fourier Grid Hamiltonian method have been compared with analytical values of the fitted Morse potential. The effect of temperature, pulse envelops function, and light intensity on the dissociation process has been explored.
Density Functional Theory Investigation of Structures and Electronic Spectra of N-protonated Corroles
Authors: Gao Hui-ling , Yao Guo-hua , Chen Fang , Wang Wen-lou , Chen Dong-ming
Published: July 2012

The geometries and electronic spectra of a series of N-protonated corroles, including unsubstituted H4Cor+ and meso-triaryl substituted H4TPC+, H4TpFPC+, and H4TdCPC+, were theoretically studied with density functional theory (DFT). The results indicate that all these compounds have two conformers, one with C2 symmetry (denoted as S1) is more stable than the other (denoted as S2, C1 symmetry) by 15.8–18.5 kJ/mol. The corrole macrocycles of these compounds show significant out-of-plane deformation. The enantiomerizations of the chiral S1 conformers were found to be a multi-step process with the S2 conformers as the intermediates. Electronic absorption spectra and electronic circular dichroism (ECD) of these compounds were calculated with time-dependent DFT. In comparison with H4Cor+, the UV-Vis absorptions of meso-triaryl species are significantly red-shifted and their Q bands are enhanced due to the π-π conjugation between the aryl and corrole rings. Several neighboring electronic transitions were calculated with opposite signs in rotatory strengths, suggesting that ECD spectroscopy may be a useful tool in studying the electronic transitions of these compounds.
Time-dependent Wave Packet Quantum Scattering Study of Reaction S(3P)+H2→HS+H on a Newab initioPotential Energy Surface 3A′
Authors: Lv Shuang-jiang , Zhang Pei-yu , He Guo-zhong
Published: July 2012

A new potential energy surface is presented for the triplet state 3A′ of the chemical reaction S(3P)+H2 from a set of accurate ab initio data. The single point energies are computed using highly correlated complete active space self-consistent-field and multi-reference configuration interaction wave functions with a basis set of aug-cc-pV5Z. We have fitted the full set of energy values using many-body expansion method with an Aguado-Paniagua function. Based on the new potential energy surface, we carry out the time-dependent wave packet scattering calculations over the collision energy range of 0.8-2.2 eV. Both the centrifugal-sudden approximation and Coriolis Coupling cross sections are obtained. In addition, the total reaction probabilities are calculated for the reactant H2 initially in the vibrational states v=0–3 (j=0). It is found that initial vibrational excitation enhances the title reaction.
3D-QSAR and Docking Studies of Pyrido[2,3-d]pyrimidine Derivatives as Wee1 Inhibitors
Authors: Zeng Guo-hua , Wu Wen-juan , Zhang Rong , Sun Jun , Xie Wen-guo , Shen Yong
Published: July 2012

In order to investigate the inhibiting mechanism and obtain some helpful information for designing functional inhibitors against Wee1, three-dimensional quantitative structure-activity relationship (3D-QSAR) and docking studies have been performed on 45 pyrido[2,3-d] pyrimidine derivatives acting as Wee1 inhibitors. Two optimal 3D-QSAR models with significant statistical quality and satisfactory predictive ability were established, including the CoMFA model (q2=0.707, R2=0.964) and CoMSIA model (q2=0.645, R2=0.972). The external validation indicated that both CoMFA and CoMSIA models were quite robust and had high predictive power with the predictive correlation coefficient values of 0.707 and 0.794, essential parameter rm2 values of 0.792 and 0.826, the leave-one-out r2m(LOO) values of 0.781 and 0.809, r2m(overall) values of 0.787 and 0.810, respectively. Moreover, the appropriate binding orientations and conformations of these compounds interacting with Wee1 were revealed by the docking studies. Based on the CoMFA and CoMSIA contour maps and docking analyses, several key structural requirements of these compounds responsible for inhibitory activity were identified as follows: simultaneously introducing high electropositive groups to the substituents R1 and R5 may increase the activity, the substituent R2 should be smaller bulky and higher electronegative, moderate-size and strong electron-withdrawing groups for the substituent R3 is advantageous to the activity, but the substituent X should be medium-size and hydrophilic. These theoretical results help to understand the action mechanism and design novel potential Wee1 inhibitors.
Influence of Sedimentation on Crystallization of Charged Colloidal Particles
Authors: Du Xuan , Xu Sheng-hua , Sun Zhi-wei , Liu Lei
Published: July 2012

The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions on dynamic behavior of a colloidal system. Experiments on crystallization of charged colloidal microspheres with diameter of 98 nm dispersed in density-matched and -unmatched media (mixtures of H2O and D2O in proper proportion) are compared to examine the influence of sedimentation. Reflection spectra of colloidal suspensions were used to monitor the crystallization process. Results showed that the crystal size of the density-unmatched (namely, in the presence of sedimentation) sample grew faster than that of the density-matched (in the absence of sedimentation) case at the initial stage of the crystallization, and then the latter overtook and outstripped the former. To explain these observations, we assume that in the settling of crystals sedimentation facilitates result in more particles getting into the crystal structures. However, as the crystals increase to varying sizes, the settling velocities become large and hydrodynamic friction strips off some particles from the delicate crystal structures. Overall, the sedimentation appears to accelerate the crystal size growth initially and then retard the growth. In addition, the crystal structures formed under microgravity were more closely packed than that in normal gravity.
Distinct roles of AKT isoforms in regulating β1-integrin activity, migration, and invasion in prostate cancer
Authors: Virtakoivu Reetta , Pellinen Teijo , Rantala Juha K. , Perälä Merja , Ivaska Johanna
Published: July 2012

AKT1 and AKT2 kinases have been shown to play opposite roles in breast cancer migration and invasion. In this study, an RNA interference screen for integrin activity inhibitors identified AKT1 as an inhibitor of β1-integrin activity in prostate cancer. Validation experiments investigating all three AKT isoforms demonstrated that, unlike in breast cancer, both AKT1 and AKT2 function as negative regulators of cell migration and invasion in PC3 prostate cancer cells. Down-regulation of AKT1 and AKT2, but not AKT3, induced activation of cell surface β1-integrins and enhanced adhesion, migration, and invasion. Silencing of AKT1 and AKT2 also resulted in increased focal adhesion size. Importantly, the mechanisms involved in integrin activity regulation were distinct for the two AKT isoforms. Silencing of AKT1 relieved feedback suppression of the expression and activity of several receptor tyrosine kinases, including EGFR and MET, with established cross-talk with β1-integrins. Silencing of AKT2, on the other hand, induced up-regulation of the microRNA-200 (miR-200) family, and overexpression of miR-200 was sufficient to induce integrin activity and cell migration in PC3 cells. Taken together, these data define an inhibitory role for both AKT1 and AKT2 in prostate cancer migration and invasion and highlight the cell type–specific actions of AKT kinases in the regulation of cell motility.
Workers, Marginalised Voices and the  Employment Tribunal System: Some Preliminary Findings
Authors: BUSBY NICOLE , MCDERMONT MORAG
Published: July 2012

This paper reports on pilot study research which sought to explore perceptions and experiences of vulnerable employees who attempted to use the Employment Tribunal (ET) system to resolve disputes. We interviewed clients of a Citizens Advice Bureau seeking to explore the concerns of those for whom the system potentially poses the greatest barriers—those who cannot afford legal advice and/or are not trade union members. We conclude that the ETs, and the mediating role played by Acas, produce barriers to justice for vulnerable employees. Furthermore, the role played by Citizens Advice is critical in reclaiming labour law’s public law function, by which private disputes between individuals are translated into matters of public concern.
Bacterial infections
Authors: van de Beek Diederik , Farrar Jeremy , Thwaites Guy
Published: July 2012

Bacterial meningitis occurs in a number of clinical situations, including spontaneous (the most important category), post-traumatic, and device-associated (relating to cerebrospinal fluid shunts and drains). Each of these is associated with a particular pattern of infecting organisms, clinical presentation and outcome, but overall there is high morbidity and mortality....
Dealing with pain
Authors: McQuay Henry
Published: July 2012

Pain is complex—it is too simple to view pain transmission as a hard-wired, line-labelled system, because that cannot explain complexities such as phantom limb pain. The crucial mechanistic distinction for clinical practice is between normal (nociceptive) and nerve damage (neuropathic) pain.

Types of analgesics—conventional analgesics, from paracetamol through to morphine, work well in nociceptive pain and less well in neuropathic pain. Unconventional analgesics, antidepressants, and antiepileptic drugs work well in neuropathic and less well in nociceptive pain....
Adaptive immunity
Authors: Klenerman Paul
Published: July 2012

Following the innate immune response, which acts very rapidly, the adaptive immune response plays a critical role in host defence against infectious disease. Unlike the innate response, which is triggered by pattern recognition of pathogens, i.e. features that are common to many bacteria or viruses, the adaptive response is triggered by structural features—known as antigens or epitopes—that are typically unique to a single organism....
Physiological changes, clinical features, and general management of infected patients
Authors: Rice Todd W. , Bernard Gordon R.
Published: July 2012

The host response to an infectious stimulus involves an intricate link between the inflammatory and coagulation systems, also mechanisms designed to limit damage to normal tissues. Key elements are: (1) the inflammatory cascade—antigens from infectious agents stimulate macrophages and monocytes (and other cells) via Toll-like receptors to release tumour necrosis factor ...
Immunization
Authors: Goldblatt D. , Ramsay M.
Published: July 2012

Immunization is one of the most successful medical interventions ever developed: it prevents infectious diseases worldwide.

Mechanism of effect—the basis for the success of immunization is that the human immune system is able to respond to vaccines by producing pathogen-specific antibody and memory cells (both B and T cells) which protect the body should the pathogen be encountered....
Poxviruses
Authors: Smith Geoffrey L.
Published: July 2012

Poxviruses are large, complex DNA viruses that have played several seminal roles in medicine and biological science. Cowpox virus was introduced by Jenner as the first human vaccine in 1796; widespread vaccination with vaccinia virus led to the global eradication of smallpox in 1977, the only human disease to have been eradicated....
Hepatitis C
Authors: Klenerman Paul , Jeffery K.J.M. , Collier J.
Published: July 2012

Hepatitis C virus (HCV) is an RNA virus that has evolved into multiple genotypes (1–6) and subtypes. Humans are the only known natural host. HCV replication is highly error-prone, hence within any one person the virus exists as a swarm of closely related variants, known as ‘quasispecies’....
HTLV-1, HTLV-2, and associated diseases
Authors: Verdonck Kristien , Gotuzzo Eduardo
Published: July 2012

Human T-lymphotropic virus (HTLV)-1 and HTLV-2 belong to the genus Deltaretrovirus of the family Retroviridae. They only infect humans, produce a lifelong infection, and can be transmitted from mother to child, through sexual intercourse, and via cellular blood components. Both viruses are present in all continents. The highest HTLV-1 prevalence in the general population (10%) has been found in southern Japan. There are endemic foci of HTLV-2 among native Amerindians and Central African pygmy tribes. HTLV-2 is also frequent among injecting drug users. It is unclear why some infected people develop associated diseases while others remain asymptomatic....
Viruses and cancer
Authors: Weiss R.A.
Published: July 2012

Viruses are important in cancer for three main reasons: (1) As a cause of cancer—about 15% of the worldwide cancer burden is due to viruses: retroviruses can activate cellular oncogenes; (2) In understanding of the biology of cancer—through the discovery and characterization of oncogenes and tumour-suppressor genes. (3) In the treatment of cancer—some viruses selectively replicate in and destroy proliferating cells, viruses as foreign antigens may aid the recognition of cancer cells by the host’s immune system (‘xenogenization’), and viruses can also be used as vectors for immunization and for gene therapy. Viral cancers are prevented by early screening for tumours, screening for the virus in order to prevent transmission, and immunization as in the cases of hepatitis B virus (HBV) and human papilloma virus (HPV)...
Other Yersinia infections: yersiniosis
Authors: Prentice Michael B.
Published: July 2012

Yersiniosis is caused by the enteropathogenic Gram-negative organisms Yersinia enterocolitica and Yersinia pseudotuberculosis, which are worldwide zoonotic pathogens. Disease is acquired by consumption of contaminated food or water and is commonest in childhood, and in colder climates. Presentation is with diarrhoea, fever and abdominal pain, which may mimic appendicitis. Late complications include reactive arthritis, erythema nodosum, and erythema multiforme. Systemic infection is more likely with ...
Actinomycoses
Authors: Schaal K.P.
Published: July 2012

Human actinomycoses are always synergistic polymicrobial infections in which fermentative actinomycetes—predominantly Actinomyces israelii, A. gerencseriae, or Propionibacterium propionicum—are the principal pathogens, usually needing the assistance of so-called concomitant microbes to produce disease. Nearly all of the members of the mixed actinomycotic microflora belong to the indigenous microbial community of human mucous membranes, hence actinomycoses present as sporadic endogenous infections which are not transmissible....
Chagas disease
Authors: Miles M.A.
Published: July 2012

A poeira de Curvelo não az mal para ninguém não

Do pulmão lá ninguém morre

O que mata é o coração

The dust of Curvelo does not harm anybody

No one dies there of lung disease...
Leishmaniasis
Authors: Bryceson A.D.M. , Lockwood Diana N.J.
Published: July 2012

Leishmaniasis is caused by parasites of the genus Leishmania, which are transmitted to humans from human or animal reservoirs by the bites of phlebotomine sandflies. In places the disease is common and important, with perhaps 500 000 cases of visceral leishmaniasis and 1.5–2 million cases of cutaneous leishmaniasis worldwide each year. As an imported disease, cutaneous leishmaniasis is common in travellers, military personnel, and immigrants coming from endemic areas, while the diagnosis of the less common visceral leishmaniasis is frequently overlooked....
Minimal-change nephropathy and focal segmental glomerulosclerosis
Authors: Adu Dwomoa
Published: July 2012

Minimal-change nephrotic syndrome (MCNS) is an immune-mediated condition, usually of unknown cause, but which can sometimes be associated with Hodgkin’s disease or the use of nonsteroidal anti-inflammatory drugs. On light microscopy the glomeruli appear normal or small, and on electron microscopy there is effacement of epithelial-cell foot processes over the outer surface of the glomerular basement membrane. MCNS is the cause of about 80% of cases of nephrotic syndrome in children and 20% in adults....
The kidney in systemic vasculitis
Authors: Jayne David
Published: July 2012

Systemic vasculitis can occur as a primary autoimmune disorder, or as a secondary manifestation of another disease process (e.g. related to infection, malignancy, chronic inflammatory disorder, or drugs). Primary systemic vasculitis is classified according to the predominant size of blood vessel involved and the presence of circulating antineutrophil cytoplasmic autoantibodies (ANCA). Incidence and prevalence rates are between 15 and 20 per million and 200 to 400 per million population, respectively. Vasculitic syndromes frequently involve the kidney, causing tissue infarction, loss of function and rapid progression to end stage renal disease within weeks or months....
Sickle-cell disease and the kidney
Authors: Serjeant G R
Published: July 2012

The vasa rectae system of the renal medulla is uniquely conducive to sickling, which leads to vascular damage and tubular dysfunction, including an inability to concentrate the urine. Renal presentations include nocturnal enuresis, haematuria (thought to be due to ischaemic lesions of the papillae, including papillary necrosis), and gradually progressive chronic renal failure, which is an important cause of morbidity and death in patients with homozygous sickle-cell disease over the age of 40 years....
Drugs and the kidney
Authors: Burns Aine , Ashley Caroline
Published: July 2012

The kidney plays a critical role in the elimination of many drugs from the body, hence consideration should be given to a patient’s renal function whenever any drug is prescribed. Much kidney disease is unrecognized, but the widespread reporting of estimated glomerular filtration rates (eGFR) has brought greater awareness of the prevalence of chronic kidney disease (CKD) and thereby encouraged medical practitioners to take account of reduced renal function when prescribing. CKD is very often one of many coexisting comorbid conditions, especially in elderly patients, when particularly careful thought must be given to appropriate drug dosing and the possibility of drug interactions....
Papulosquamous disease
Authors: Griffiths Christopher
Published: July 2012

Papulosquamous diseases are typically characterized by well-demarcated areas of papules and scale, typically on an erythematous background. The differential diagnosis includes psoriasis, lichen planus, mycosis fungoides, discoid lupus erythematosus, eczema/dermatitis, drug eruptions, tinea, pityriasis versicolor, secondary syphilis, and pityriasis rosea.

The presence of significant pruritus is a useful marker to help with the differential diagnosis: lichen planus and discoid eczema are typically pruritic, whereas others, such as psoriasis, are less so. The distribution is also key to making the diagnosis, with psoriasis often showing characteristic symmetrical involvement of the extensor surfaces, scalp, and nails. Histology can be essential to reach a diagnosis and plan an appropriate approach to management....
Acute behavioural emergencies
Authors: Feldman Eleanor
Published: July 2012

Acute behavioural problems can present in any unit in a general hospital. The first priority is to discover whether or not the patient is severely physically ill and suffering from delirium, in which case—apart from managing the behavioural disturbance—treatment clearly needs to be directed towards the primary cause....
Grief, stress, and post-traumatic stress disorder
Authors: Dalgleish Tim , Yiend Jenny , Golden Ann-Marie J.
Published: July 2012

Grief—this is the constellation of psychological responses to the loss of a loved one. Normal grief arguably develops in stages and dissipates in strength and impact over time. Some people (14–34%) suffer from pathological grief, where intense emotional distress and impairment of functioning persist for 6 months or more. This is often comorbid with other psychiatric disorders. Grief—and pathological grief in particular—carry an increased risk of mortality in the bereaved person, hence treatment of pathological grief using psychological therapy is advised....
Chronic fatigue syndrome (postviral fatigue syndrome, neurasthenia, and myalgic encephalomyelitis)
Authors: Sharpe Michael
Published: July 2012

Chronic fatigue syndrome (CFS) is also known as postviral fatigue syndrome, neurasthenia, and myalgic encephalomyelitis. All describe an idiopathic syndrome characterized by disabling fatigue and other symptoms occurring chronically and exacerbated by minimal exertion.

Aetiology and pathogenesis—it is likely that multiple factors operate to predispose, precipitate, and perpetuate CFS: (1) predisposing factors—some individuals may be predisposed to develop CFS by virtue of genetics, personality, or other vulnerability; (2) precipitating factors—the condition may be precipitated by factors such as infection or psychological stresses; (3) perpetuating factors—for practical management the most important factors are those that perpetuate the illness and consequently act as barriers to recovery, including modifiable psychological, biological, behavioural, and social factors. Studies have reported a variety of biological abnormalities: few have been confirmed, but the most robust are (1) altered brain function, and (2) reduced hypothalamic-pituitary-adrenal axis responsiveness, although it is not clear if these are primary or secondary to inactivity....
Schizophrenia, bipolar disorder, obsessive–compulsive disorder, and personality disorder
Authors: Lawrie Stephen
Published: July 2012

Schizophrenia—is characterized by phenomena that qualitatively differ from everyday experience. These may be ‘positive symptoms’, commonly auditory hallucinations and/or bizarre delusions, or ‘negative symptoms’, commonly including a loss of emotion (flat affect), apathy, self-neglect, and social withdrawal. Acute positive symptoms generally respond well to any antipsychotic drug, but prognosis is often poor, with most suffering chronic symptoms, numerous relapses, unemployment, and social isolation....
Alcohol and drug dependence
Authors: McCaul Mary E. , Wand Gary S. , Olsen Yngvild K.
Published: July 2012

Alcohol and drug dependence are diagnosed based on the clustering of characteristic physiological and behavioural symptoms. Since there is considerable diagnostic overlap with a variety of medical and psychiatric conditions, a careful history of a patient’s substance use, associated problems, and familial patterns of substance misuse is important....
Methodology for Inoculating Sweetpotato Virus Disease: Discovery of Tip Dieback, and Plant Recovery and Reversion in Different Clones
Authors: Mwanga R. O. M. , Yencho G. C. , Gibson R. W. , Moyer J. W.
Published: July 2012

Evaluating sweetpotato (Ipomoea batatas) genotypes for resistance to sweetpotato virus disease (SPVD) has been slow and inefficient. Ipomoea setosa plants, normally used as the source of scions for graft-infecting sweetpotatoes with viral diseases, are often severely stunted and their mortality is 10 to 30% when infected with SPVD, making them unsuitable as scions. Tanzania, a landrace of I. batatas widely grown in East Africa, was found to be a superior host for maintaining and increasing SPVD inoculum (scions) for mass grafting. Modifications to a cleft-grafting technique also increased survival of grafted SPVD-affected scions from 5 to 100%. These modifications, coupled with an efficient SPVD scoring technique, allowed rapid screening of large sweetpotato populations for SPVD resistance. Plant recovery from SPVD is reported here as a component of SPVD resistance. Differences in recovery from SPVD were detected among progenies, indicating its genetic basis. Plant tip dieback, a hypersensitivity response, was observed only in families with cv. Wagabolige as a parent. These findings may open up new opportunities for improved understanding and control of this devastating disease.
Biological and Molecular Characterization of a U.S. Isolate of Hosta virus X
Authors: De La Torre Carola M. , Qu Feng , Redinbaugh Margaret G. , Lewandowski Dennis J.
Published: July 2012

Hosta virus X (HVX) is rapidly becoming a serious pathogen of commercially important hosta plants worldwide. We report here biological and molecular characterization of a U.S. isolate of HVX, HVX-37. HVX-37 infectivity was tested in 21 hosta cultivars over three growth seasons, and three types of responses were defined based upon the ability of the virus to cause local and/or systemic infections. Four cultivars resistant to systemic HVX infection were identified. The full-length sequence of the HVX-37 genome was determined, the first complete sequence of a U.S. HVX isolate. Comparison with the previously sequenced HVX-Korea (Kr) genome revealed a high level of sequence similarity, as well as some differences. Notably, a 105-nucleotide long, near-perfect direct repeat in the Kr isolate is absent in HVX-37. The accuracy of the HVX-37 genome sequence was confirmed by infectivity of in vitro transcripts synthesized from a full-length HVX-37 cDNA on Nicotiana benthamiana and hosta plants.
Molecular surveillance and phylogenetic analysis of Old World arenaviruses in Zambia
Authors: Ishii Akihiro , Thomas Yuka , Moonga Ladslav , Nakamura Ichiro , Ohnuma Aiko , Hang’ombe Bernard M. , Takada Ayato , Mweene Aaron S. , Sawa Hirofumi
Published: July 2012

In order to survey arenaviruses in the Republic of Zambia, we captured 335 rodents from three cities between 2010 and 2011. Eighteen Luna virus (LUNV) and one lymphocytic choriomeningitis virus (LCMV)-related virus RNAs were detected by one-step RT-PCR from Mastomys natalensis and Mus minutoides, respectively. Four LUNV strains and one LCMV-related virus were isolated, and the whole genome nucleotide sequence was determined by pyrosequencing. Phylogenetic analyses revealed that the LUNV clade consists of two branches that are distinguished by geographical location and that the LCMV-related virus belongs to the LCMV clade, but diverges from the typical LCMVs. Comparison of nucleoprotein amino acid sequences indicated that the LCMV-related virus could be designated a novel arenavirus, which was tentatively named as the Lunk virus. Amino acid sequences of the GP, NP, Z and L proteins showed poor similarity among the three Zambian arenavirus strains, i.e. Luna, Lunk and Lujo virus.
Migratory behaviour of a dominant detritivorous fish Prochilodus lineatus evaluated by multivariate biochemical and pollutant data
Authors: Speranza E. D. , Cappelletti N. , Migoya M. C. , Tatone L. M. , Colombo J. C.
Published: July 2012

This paper studies the migration pathways and ranges of a dominant detritivorous fish Prochilodus lineatus along pollution gradients in the Río de la Plata basin using multivariate analysis of biochemical and pollutant data. Biochemical composition (water, ash, lipids, proteins, carbohydrates, neutral lipids classes and fatty acids), aliphatic hydrocarbons (ALI), polychlorinated biphenyls (PCB), linear alkylbenzenes (LAB) and organochlorine pesticides (OClP) were determined in muscle samples of P. lineatus collected in Metropolitan Buenos Aires, the lower Paraná River (Paraná: 200–1000 km from Buenos Aires) and the middle Paraná and Paraguay Rivers (North: 1000–1400 km north). Biochemical variables and pollutants exhibited large variability [Lipids 1·1–89·5% wet mass; ALI 1·4–413; LABs not detectable (n.d.)–115·2; PCBs n.d.–27·9; OClPs n.d.–11·8 µg g−1 dry mass], due to the contrast of Buenos Aires with North fish. Fish from Buenos Aires were fatty (lipids 24·7 ± 12·3% wet mass), enriched in 18 carbon fatty acids and severely contaminated (ALI 152·4 ± 72·3; LABs 65·1 ± 26·4; PCBs 15·2 ± 6·8; OClPs 1·8 ± 1·9 µg g−1 dry mass mean ±s.d.). In contrast, fish from North were lean (4·1 ± 3·1% wet mass), enriched in long chain (>20 carbons) polyunsaturated fatty acids, with average one to two orders of magnitude lower pollutant levels (ALI 41·2 ± 51·9; PCBs 2·2 ± 3·5; LABs 8·8 ± 21·1; OClPs 0·67 ± 0·75 µg g−1 dry mass mean ±s.d.). Paraná showed intermediate values in all variables, denoting the mixing of different fish stocks. Based on principal component analysis, 14 outliers from 60 North and Paraná samples (representing 26 from 108 individual fish) were identified as pertaining to the Buenos Aires group with very similar lipid and pollutant levels. Data suggest that P. lineatus migrates a highly variable distance, exceeding 800–1000 km in multiple spatial and temporal overlapping ranges. Chemometric analysis of biochemical and pollutant data effectively discriminates fish according to the chemical signature acquired by detritus feeding in pristine and contaminated urban or industrial areas.
Spawning migration of American eel Anguilla rostrata from pristine (1843–1872) to contemporary (1963–1990) periods in the St Lawrence Estuary, Canada
Authors: Verreault G. , Mingelbier M. , Dumont P.
Published: July 2012

Daily American eel Anguilla rostrata catches and their dates of passage (starting, median and ending dates) were compared between pristine (1843–1872) and contemporary periods (1963–1990) to determine any changes and see whether these were related to environmental variations and water discharge regulation. Timing and duration of A. rostrata migration patterns differed significantly between the two periods. In the contemporary period, migrating A. rostrata were intercepted significantly earlier than in pristine times (18 days earlier on average), and ended at the same average period. Early A. rostrata migration was also significantly related to high spring flow and secondarily to high spring temperature, while migration ended later when high temperature or low water level occurred during the autumn period. A recent slight increase in the water temperature of the St Lawrence River could partially explain the earlier A. rostrata migration observed during the contemporary period. In return, the effect of high spring flow should have been more contrasted if the river discharge would have not been regulated. Recent A. rostrata production now being mainly restricted to the lower part of St Lawrence River mainstream, resulting shorter travelling distance to the estuary may explain why migrating progress was earlier during the contemporary period.
Homing and group cohesion in Atlantic cod Gadus morhua revealed by tagging experiments
Authors: Tamdrari H. , Brêthes J.‐C. , Castonguay M. , Duplisea D. E.
Published: July 2012

Homing behaviour and group cohesion in Atlantic cod Gadus morhua from the northern Gulf of St Lawrence were studied based on tagging–recapture data from two periods, the 1980s and a recent period from 1996 to 2008. Two or more tags from a single tagging experiment were frequently recovered together in subsequent years. The null hypothesis was tested that the frequency of matching tag recoveries occurred by chance only through random mixing of tagged G. morhua before their recapture by the commercial fishery. The alternative hypothesis was that non‐random, positive association (group cohesion) existed among tagged individuals that persisted through time and during migrations. Results show that the G. morhua population exhibits a homing behaviour, with temporal stability across seasons and years: 50% of recaptured fish in the recent period were caught <34 km from their mark site, even 3 years after release. In the 1980s, G. morhua were located at <10 km from their release site 1 year after tagging during summer and at <16 km during spring and autumn combined. Despite the increasing distance between the mark and recapture sites over time, the difference was not significant. In addition, occurrences of two or more tagged fish from the same release event that were caught together indicated a non‐random association among individual fish for periods of one to several years and through migrations over several hundred kilometres. Hence G. morhua showed group cohesion in addition to site fidelity. These two interacting behaviours may be fundamental for the rebuilding and conservation of depleted fish stocks.
Effects of small‐scale environmental variation on metaphyton condition and community composition
Authors: SAUNDERS LYNNETTE L. , KILHAM SUSAN S. , WINFIELD FAIRCHILD G. , VERB ROBERT
Published: July 2012

1. Metaphyton mats typically originate as benthic algal biofilms that experience higher solar radiation and temperatures, and reduced access to nutrients, once they reach the water surface, but the impacts of these physicochemical changes on metaphyton condition and community composition have received little attention.

2. Using microprobes positioned at 0, 2, 4 and 6 cm depth, we recorded small‐scale differences in water chemistry within metaphyton mats constrained in floating nets during an 8‐week period. Concurrent weekly samples of filamentous algae and their diatom epiphytes were collected from the top, middle and bottom of the mats and were analysed for changes in ash‐free dry mass (AFDM) and chlorophyll‐a, nutrient (N, P, C, Si) content and taxonomic composition.

3. Light intensity, temperature and dissolved oxygen declined both with increasing depth in the mat and over the study period. The autotrophic index (=AFDM/chlorophyll‐a) was greatest at the top of the mats and increased over time; samples also had higher C/P and C/N ratios than samples deeper within the mat.

4. Pithophora was consistently the dominant algal filament throughout the study (representing 85% of all filaments averaged over time and depth); epiphytic diatom cover on Pithophora (calculated as epiphyte area index) declined over time, particularly at the top of the mat.

5. Densities of the diatom epiphytes Gomphonema, Cocconeis and Fragilaria increased with increasing depth within the mat, whereas Cymbella/Encyonema was more common in surface samples.

6. Our results indicate that metaphyton mats are highly dynamic communities, spatially organised in part by small‐scale environmental variation and subject to changes in taxonomic composition following their arrival at the water surface.