bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarimetric localization: A new tool for calculating the CME speed and direction of propagation in near‐real time
Authors: de Koning Curt A. , Pizzo V. J.
Published: March 2011

The polarimetric localization technique uses the percent polarization observed by a single coronagraph to obtain a three‐dimensional reconstruction of a coronal mass ejection (CME). We use this technique to analyze STEREO/SECCHI/COR2 beacon data for 12 different events at spacecraft separations ranging from 9° to 127°. To determine if the technique is efficacious, we compare the three‐dimensional location and velocity, including speed and direction, computed by polarimetric localization to the same quantities computed by geometric localization. The geometric localization technique utilizes a series of lines of sight from two space‐based coronagraphs to determine gross propagation characteristics of CMEs in three‐dimensional space. In particular, we present a detailed comparison of the techniques for two events: the first example is from very early on in the mission, on 23 May 2007, when the spacecraft separation was only 9.2°, and the second event is from 12 December 2008, when the spacecraft were almost in quadrature. We find that the two techniques yield comparable CME velocities; furthermore, both are straightforward to apply and they can be used in near‐real time. In conclusion, we believe that these techniques promise a substantial improvement in our capability to locate and characterize CMEs for forecasting, as well as research purposes.
Identification of nonlinearity in rainfall‐flow response using data‐based mechanistic modeling
Authors: McIntyre Neil , Young Peter , Orellana Barbara , Marshall Miles , Reynolds Brian , Wheater Howard
Published: March 2011

Data‐based mechanistic (DBM) modeling is an established approach to time series model identification and estimation, which seeks model structures and parameters that are both statistically optimal and consistent with plausible mechanistic interpretations of the system. This paper describes the application of the DBM method to 10 min, relatively high precision, rainfall‐flow data, including observations of both surface flow and subsurface flow. For a generally wet winter period, the preferred surface flow model is nonlinear in flow generation and linear in routing, while the preferred subsurface flow model is linear in flow generation and nonlinear in routing. These models have mechanistic interpretations in terms of mass balance, hydrodynamics, and conceptual flow pathways. The four‐parameter surface and subsurface flow models explain 91% and 96% of the variance of the corresponding observations. Other plausible models were identified but were less parsimonious or were more reliant on prior perceptions. For a wet summer validation period, the models performed as well as in the calibration period; however, when a long dry spell was included, the performance deteriorated. It is speculated that this is because of complex wetting‐drying dynamics and potential nonstationarity of the soil properties that are not sufficiently revealed in the available data. Conceptual models informed by the DBM results matched the DBM model performance for subsurface flow but gave poorer performance for the more complex surface flow responses. It is concluded that the DBM method can identify nonlinearity in both flow generation and routing and provide conceptual insights that can go beyond prior expectations.
Artificial synthetic receptors as regulators of protein activity
Authors: Dutt Som , Wilch Constanze , Schrader Thomas
Published: March 2011

Superimposed snapshots of a MD simulation for the ternary complex between G6PD, a molecular clip and included NADP+ cofactor.
Personality and Voice Disorders
Authors: Roy Nelson
Published: March 2011

It has been argued that personality, emotions, and psychological problems contribute to or are primary causes of voice disorders, and that voice disorders in turn create psychological problems and personality effects. This article provides an overview of recent concepts in personality and trait structure, briefly summarizes the “Trait Theory” which explains how personality may contribute to the development of primary muscle tension dysphonia and vocal nodules, reviews research aimed at testing the Trait Theory, and discusses clinical implications related to recognizing personality as a factor in the development, maintenance, and treatment of primary muscle tension dysphonia and vocal nodules.
Voice Disorders and Personality: Understanding Their Interactions
Authors: van Mersbergen Miriam
Published: March 2011

This article will address some of the theory and research in personality psychology that are used to answer questions associated with the relation between personality and voice disorders. The study of personality is important to consider in voice disorders, because personality determines the manner in which each person shapes and reacts to his or her environment. In this article, a review of personality psychology is presented along with research findings from voice science and personality. Implications for clinical practice in particular groups of individuals with voice disorders are discussed.
Emotional Expression and Voice Dysfunction
Authors: Rammage Linda
Published: March 2011

In this article, the perceptual-motor theory of emotion is summarized and explained in the context of general and vocal emotional expression. A case example from our voice clinic is used to illustrate the usefulness of the theory for speech-language pathologists, and to highlight how collaborative work with a psychiatrist specializing in voice disorders enhances treatment outcomes.
Crystal Structures, Antioxidation, and DNA Binding Properties of SmIII Complexes
Authors: Liu Yongchun , Yang Zhengyin , Zhang Kejun , Wu Yun , Zhu Jihua , Zhou Tianlin
Published: March 2011

The dinuclear SmIII complexes with 1:1 metal to ligand stoichiometry were prepared from Sm(NO3)3·6H2O and three anionic tetradentate Schiff-base ligands derived from 8-hydroxyquinoline-2-carboxyaldehyde with benzoylhydrazine, 2-hydroxybenzoylhydrazine, and isonicotinylhydrazine, respectively. All the ligands and complexes can bind strongly to calf thymus DNA through intercalation with the binding constants at 105–106 M–1, but complexes present stronger affinities to DNA than ligands. All the ligands and complexes have strong abilities of antioxidation, but complexes and ligands containing an active phenolic hydroxy group show stronger scavenging effects on hydroxyl radical, and SmIII complex containing N-heteroaromatic substituent shows stronger scavenging effects for superoxide radical.
Critical Design Factors for Optical Imaging with Metal Coordination Complexes
Authors: Parker David
Published: March 2011

Metal coordination complexes are emerging as an important class of optical imaging probes. They may function not only as stains for particular cell compartments, but also as responsive probes, able to report on changes in local ionic composition. The critical factors to consider in designing such probes are reviewed, including issues of cell uptake and compartmentalization, the degree of non-invasiveness and their functional performance. Prospects are considered for the development of lanthanide(iii) probes capable of reporting changes in local bicarbonate, citrate, and lactate.
Ring Opening Metathesis Polymerization of Polyoctahedral Oligomeric Silsesquioxanes (POSS) Incorporated Oxanorbornene-5,6-dicarboximide: Synthesis, Characterization, and Surface Morphology of Copolymers
Authors: Gnanasekaran D. , Madhavan K. , Tsibouklis John , Reddy B. S. R.
Published: March 2011

The synthesis and characterization of N-propyl-POSS-7-oxanorbornene-5,6-dicarboximide (NPONDI) and N-3-(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide (TFNDI) was reported. The synthesis of the POSS-based (co)polymers were accomplished by ring opening metathesis polymerization (ROMP). The monomers and polymers were characterized using FT-IR, 1H-, 13C-, 29Si-NMR, and GPC techniques. Thermal properties of TFNDI-NPONDI copolymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Transmission electron microscopic (TEM) analysis of optically transparent and flexible copolymer films revealed the presence of 50 nm-sized POSS agglomerates. Atomic force microscopy analysis of the film surface exhibited a modest increase in surface roughness of TFNDI-NPONDI copolymers as compared with homopoly[N-3(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide] (HTFNDI). The POSS incorporated polymers such as 1NPONDI, 2NPONDI, and 3NPONDI increased the hydrophobicity as compared with HTFNDI. This was measured by static contact angle analysis. The study focussed on the dispersion, surface morphology, and the microstructure of POSS in TFNDI-NPONDI copolymer as determined by scanning electron microscopy (SEM).
Interaction and Electron Density Properties of MKr42+ (M=Cu, Ag and Au): ab initio Calculation
Authors: Xinying Li , Xue Cao
Published: March 2011

Quantum chemical calculations of the structures and stabilities of the MKr42+ series at the CCSD(T) theoretical level have been performed. The role of the interaction was investigated using the natural bond orbital (NBO), Laplacian, electron density deformation, electron localization function and reduced density gradient analysis. The results show that a covalent contribution occurs in the Kr-M2+ bonding.
Self-ordering Electrochemistry: A Simple Approach for Engineering Nanopore and Nanotube Arrays for Emerging Applications
Authors: Losic Dusan , Velleman Leonara , Kant Krishna , Kumeria Tushar , Gulati Karan , Shapter Joe G. , Beattie David A. , Simovic Spomenka
Published: March 2011

In this paper, we present recent work from our group focussed on the fabrication of nanopore and nanotube arrays using self-ordered electrochemistry, and their application in several key areas including template synthesis, molecular separation, optical sensing, and drug delivery. We have fabricated nanoporous anodic aluminium oxide (AAO) with controlled pore dimensions (20–200 nm) and shapes, and used them as templates for the preparation of gold nanorod/nanotube arrays and gold nanotube membranes with characteristic properties such as surface enhanced Raman scattering and selective molecular transport. The application of AAO nanopores as a sensing platform for reflective interferometric detection is demonstrated. Finally, a drug release study on fabricated titania nanotubes confirms their potential for implantable drug delivery applications.
A Potentially Polymerizable Heterodinuclear FeIIIZnII Purple Acid Phosphatase Mimic. Synthesis, Characterization, and Phosphate Ester Hydrolysis Studies
Authors: Zee Yoke Leng Michelle , Gahan Lawrence R. , Schenk Gerhard
Published: March 2011

An analogue of the purple acid phosphatase biomimetic 2-((bis(pyridin-2-ylmethyl)amino)methyl)-6-(((2-hydroxybenzyl)(pyridin-2-ylmethyl)amino)methyl)-4-methylphenol has been synthesized. The analogue, 2-((bis(pyridin-2-ylmethyl)amino)methyl)-6-(((2-hydroxy-4-(4-vinylbenzyloxy)benzyl)(pyridin-2-ylmethyl)amino)methyl)-4-methylphenol (H2BPBPMPV) possesses a pendant olefin suitable for copolymerization. Complexation with FeIII/ZnII resulted in the complex [FeIIIZnII(BPBPMPV)(CH3COO)2](ClO4), characterized with mass spectrometry, microanalysis, UV/vis, and IR spectrometry. The catalytic activity of the complex toward bis-(2,4-dinitrophenyl) phosphate was determined, resulting in Km of 4.1 ± 0.6 mM, with kcat 3.8 ± 0.2 × 10–3 s–1 and a bell-shaped pH–rate profile with pKa values of 4.31, 5.66, 8.96, the profile exhibiting residual activity above pH 9.5.
Metallo-oxidase Enzymes: Design of their Active Sites
Authors: Xiao Zhiguang , Wedd Anthony G.
Published: March 2011

Multi-copper oxidases are a large family of enzymes prevalent in all three domains of life. They couple the one-electron oxidation of substrate to the four-electron reduction of dioxygen to water and feature at least four Cu atoms, traditionally divided into three sites: T1, T2, and (binuclear) T3. The T1 site catalyzes substrate oxidation while a trinuclear cluster (comprising combined T2 and T3 centres) catalyzes the reduction of dioxygen. Substrate oxidation at the T1 Cu site occurs via an outer-sphere mechanism and consequently substrate specificities are determined primarily by the nature of a substrate docking/oxidation (SDO) site associated with the T1 Cu centre. Many of these enzymes ‘moonlight’, i.e. display broad specificities towards many different substrates and may have multiple cellular functions. A sub-set are robust catalysts for the oxidation of low-valent transition metal ions such as FeII, CuI, and MnII and are termed ‘metallo-oxidases’. They play essential roles in nutrient metal uptake and homeostasis, with the ferroxidase ceruloplasmin being a prominent member. Their SDO sites are tailored to facilitate specific binding and facile oxidation of these low-valent metal ions and this is the focus of this review.
Uptake and Distribution of a Platinum(II)-Carborane Complex Within a Tumour Cell Using Synchrotron XRF Imaging
Authors: Crossley Ellen L. , Aitken Jade B. , Vogt Stefan , Harris Hugh H. , Rendina Louis M.
Published: March 2011

Treatment of A549 human lung carcinoma cells with a DNA metallointercalator complex containing a PtII-terpy (terpy = 2,2′:6′,2′′-terpyridine) unit linked to a functionalized closo-carborane cage results in the uptake of the complex within the cells, as determined by synchrotron X-ray fluorescence (XRF) imaging. Although a significant cellular uptake of Pt existed, there was no significant accumulation of the element within the cell nuclei. Other statistically significant changes from the XRF data included an increase in Cl, K, and Cu and a decrease in Fe within the treated cells.
Water-soluble Bis(thiosemicarbazonato)copper(II) Complexes
Authors: Buncic Gojko , Hickey James L. , Schieber Christine , White Jonathan M. , Crouch Peter J. , White Anthony R. , Xiao Zhiguang , Wedd Anthony G. , Donnelly Paul S.
Published: March 2011

The synthesis of four new water-soluble bis(thiosemicarbazone) ligands and their copper(ii) complexes is presented and their potential to be new ligands for copper radiopharmaceuticals is discussed. The ligands and complexes have been characterized by a combination of NMR spectroscopy, mass spectrometry, and X-ray crystallography. The electrochemical behaviour of two of the copper(ii) complexes was investigated by cyclic voltammetry and revealed that both complexes exhibited a quasi-reversible redox process attributed to a CuII/CuI process. Two of the new ligands were radiolabelled with positron-emitting 64Cu with a view to assessing their potential as ligands that bind radioactive copper isotopes for application in diagnostic radiopharmaceuticals. The cellular uptake of the copper complexes was investigated in SH-SY5Y cells.
Stabilization of Triam(m)inechloridoplatinum Complexes by Oxidation to PtIV
Authors: Daly Helen L. , Hall Matthew D. , Failes Timothy W. , Zhang Mei , Foran Garry J. , Hambley Trevor W.
Published: March 2011

PtIV analogues of the active end groups {PtClN3} of multinuclear Pt anticancer drugs have been investigated. The crystal structure of trans,mer-[PtCl(OH)2(dien)]Cl shows that the bond lengths are similar to those in the dihydroxidoplatinum(iv) analogue of cisplatin. The axial ligands are shown to be the predominant influence on reduction potentials with the dihydroxido complex trans,mer-[PtCl(OH)2(NH3)3]Cl being the most resistant to reduction. X-ray absorption near-edge spectroscopy is shown to be suitable for monitoring the oxidation state of these complexes and reveals that trans,mer-[PtCl(OH)2(NH3)3]+ survives for more than 2 h in cancer cells.
Temporal dynamics of natural product biosynthesis in marine cyanobacteria
Authors: Esquenazi Eduardo , Jones Adam C. , Byrum Tara , Dorrestein Pieter C. , Gerwick William H.
Published: March 2011

Sessile marine organisms are prolific sources of biologically active natural products. However, these compounds are often found in highly variable amounts, with the abiotic and biotic factors governing their production remaining poorly understood. We present an approach that permits monitoring of in vivo natural product production and turnover using mass spectrometry and stable isotope (
15
N) feeding with small cultures of various marine strains of the natural product-rich cyanobacterial genus
Lyngbya
. This temporal comparison of the amount of in vivo
15
N labeling of nitrogen-containing metabolites represents a direct way to discover and evaluate factors influencing natural product biosynthesis, as well as the timing of specific steps in metabolite assembly, and is a strong complement to more traditional in vitro studies. Relative quantification of
15
N labeling allowed the concurrent measurement of turnover rates of multiple natural products from small amounts of biomass. This technique also afforded the production of the neurotoxic jamaicamides to be more carefully studied, including an assessment of how jamaicamide turnover compares with filament growth rate and primary metabolism and provided new insights into the biosynthetic timing of jamaicamide A bromination. This approach should be valuable in determining how environmental factors affect secondary metabolite production, ultimately yielding insight into the energetic balance among growth, primary production, and secondary metabolism, and thus aid in the development of methods to improve compound yields for biomedical or biotechnological applications.
Determinism and stochasticity during maturation of the zebrafish antibody repertoire
Authors: Jiang Ning , Weinstein Joshua A. , Penland Lolita , White Richard A. , Fisher Daniel S. , Quake Stephen R.
Published: March 2011

It is thought that the adaptive immune system of immature organisms follows a more deterministic program of antibody creation than is found in adults. We used high-throughput sequencing to characterize the diversifying antibody repertoire in zebrafish over five developmental time points. We found that the immune system begins in a highly stereotyped state with preferential use of a small number of V (variable) D (diverse) J (joining) gene segment combinations, but that this stereotypy decreases dramatically as the zebrafish mature, with many of the top VDJ combinations observed in 2-wk-old zebrafish virtually disappearing by 1 mo. However, we discovered that, in the primary repertoire, there are strong correlations in VDJ use that increase with zebrafish maturity, suggesting that VDJ recombination involves a level of deterministic programming that is unexpected. This stereotypy is masked by the complex diversification processes of antibody maturation; the variation and lack of correlation in full repertoires between individuals appears to be derived from randomness in clonal expansion during the affinity maturation process. These data provide a window into the mechanisms of VDJ recombination and diversity creation and allow us to better understand how the adaptive immune system achieves diversity.
Structural insights into a unique cellulase fold and mechanism of cellulose hydrolysis
Authors: Brás Joana L. A. , Cartmell Alan , Carvalho Ana Luísa M. , Verzé Genny , Bayer Edward A. , Vazana Yael , Correia Márcia A. S. , Prates José A. M. , Ratnaparkhe Supriya , Boraston Alisdair B. , Romão Maria J. , Fontes Carlos M. G. A. , Gilbert Harry J.
Published: March 2011

Clostridium thermocellum
is a well-characterized cellulose-degrading microorganism. The genome sequence of
C. thermocellum
encodes a number of proteins that contain type I dockerin domains, which implies that they are components of the cellulose-degrading apparatus, but display no significant sequence similarity to known plant cell wall–degrading enzymes. Here, we report the biochemical properties and crystal structure of one of these proteins, designated
Ct
Cel124. The protein was shown to be an
endo
-acting cellulase that displays a single displacement mechanism and acts in synergy with Cel48S, the major cellulosomal
exo
-cellulase. The crystal structure of
Ct
Cel124 in complex with two cellotriose molecules, determined to 1.5 Å, displays a superhelical fold in which a constellation of α-helices encircle a central helix that houses the catalytic apparatus. The catalytic acid, Glu96, is located at the C-terminus of the central helix, but there is no candidate catalytic base. The substrate-binding cleft can be divided into two discrete topographical domains in which the bound cellotriose molecules display twisted and linear conformations, respectively, suggesting that the enzyme may target the interface between crystalline and disordered regions of cellulose.
An RNAi-based chemical genetic screen identifies three small-molecule inhibitors of the Wnt/
wingless
signaling pathway
Authors: Gonsalves Foster C. , Klein Keren , Carson Brittany B. , Katz Shauna , Ekas Laura A. , Evans Steve , Nagourney Robert , Cardozo Timothy , Brown Anthony M. C. , DasGupta Ramanuj
Published: March 2011

Misregulated β-catenin responsive transcription (CRT) has been implicated in the genesis of various malignancies, including colorectal carcinomas, and it is a key therapeutic target in combating various cancers. Despite significant effort, successful clinical implementation of CRT inhibitory therapeutics remains a challenging goal. This is, in part, because of the challenge of identifying inhibitory compounds that specifically modulate the nuclear transcriptional activity of β-catenin while not affecting its cytoskeletal function in stabilizing adherens junctions at the cell membrane. Here, we report an RNAi-based modifier screening strategy for the identification of CRT inhibitors. Our data provide support for the specificity of these inhibitory compounds in antagonizing the transcriptional function of nuclear β-catenin. We show that these inhibitors efficiently block Wnt/β-catenin–induced target genes and phenotypes in various mammalian and cancer cell lines. Importantly, these Wnt inhibitors are specifically cytotoxic to human colon tumor biopsy cultures as well as colon cancer cell lines that exhibit deregulated Wnt signaling.
Assessing mating performance of male Glossina pallidipes (Diptera: Glossinidae) using a walk-in field cage
Authors: Mutika G.N. , Opiyo E. , Robinson A.S.
Published: March 2011

To monitor the quality of male tsetse for use in the sterile insect technique (SIT), a field cage test was developed and evaluated. Mating competitiveness was tested with male Glossina pallidipes Austen that emerged from pupae stored for different periods at 15°C. Control males emerged from pupae stored at 23–24°C and emerged at 26.5°C. Each sample of test males was divided into two groups with one group being irradiated at 120 Gy; the other group was not irradiated. More than 70% of the maximum possible number of mating pairs occurred in all tests. Males emerged from pupae kept at low temperature and then irradiated formed a greater proportion of mating pairs than the controls. Males emerged from pupae kept at 15°C generally started mating more quickly than the standard colony males although there was no significant difference. Insemination rates were above 99%. Pooled data indicated that mean spermathecal values for females mated with irradiated males were significantly lower than for control males. The duration of copulation varied significantly between treatment groups and was significantly longer for irradiated male flies; there was no correlation between duration of copulation and mean spermathecal value.
Bioassay and biochemical analyses of insecticide resistance in southern African Anopheles funestus (Diptera: Culicidae)
Authors: Brooke B.D. , Kloke G. , Hunt R.H. , Koekemoer L.L. , Tem E.A. , Taylor M.E. , Small G. , Hemingway J. , Coetzee M.
Published: March 2011

Anopheles funestus Giles has been implicated as a major malaria vector in sub-Saharan Africa where pyrethroid insecticides are widely used in agriculture and public health. Samples of this species from northern Kwazulu/Natal in South Africa and the Beluluane region of southern Mozambique showed evidence of resistance to pyrethroid insecticides. Insecticide exposure, synergist and biochemical assays conducted on A. funestus suggested that elevated levels of mixed function oxidases were responsible for the detoxification of pyrethroids in resistant mosquitoes in these areas. The data suggested that this mechanism was also conferring cross-resistance to the carbamate insecticide propoxur.
Population dynamics of the white wax scale, Ceroplastes destructor (Hemiptera: Coccidae), on citrus in South Africa, with implications for biological control
Authors: Wakgari W.M. , Giliomee J.H.
Published: March 2011

The population dynamics of the white wax scale, Ceroplastes destructor Newstead, was studied intensively in four easy-peel citrus orchards in the Western Cape Province of South Africa over three consecutive years (1997–1999). Key factor analysis was used to determine and quantify the contribution of individual mortality factors to the total generation mortality. Key stage mortality, determined from a cohort life table, was in the third instar and pre-ovipositing female stages. Mortality of C. destructor was caused primarily by parasitoids, predators and miscellaneous factors. Parasitoids and miscellaneous factors acted as density-dependent regulatory agents during the pre-ovipositional and first instar stages respectively. This has implications for biological control of C. destructor. Some of the mortality factors acted either randomly with no reference to the population densities or in an inverse density-dependent manner during the egg-crawler, second or third instar stages.
Family planning in a stemborer parasitoid: sex ratio, brood size and size-fitness relationships in Parallorhogas pyralophagus (Hymenoptera: Braconidae), and implications for biological control
Authors: Bernal J.S. , Gillogly P.O. , Griset J.
Published: March 2011

Various aspects were studied of the brood size and sex allocation strategies, and of size-fitness relationships in Parallorhogas pyralophagus (Marsh), a gregarious ectoparasitoid of Eoreuma loftini Dyar. Brood size was significantly correlated with host size; larger hosts were allocated larger broods. Brood sex ratios were fixed precisely at 1 male per 4 females, and eggs were likely to be deposited in that order; differential mortality did not contribute to this precise sex ratio. The sex allocation strategy of P. pyralophagus is likely to conform to strict, i.e. single foundress, local mate competition. Adoption of this strategy is probably influenced by a limited insemination capacity of males; a smaller proportion of females (0.09 vs. 0.21) remained virgin in broods with precise or higher sex ratios (≥0.20 males) relative to broods with lower than precise sex ratios (< 0.20 males). Moreover, all females were inseminated in most broods (60%) with precise or higher sex ratios, whereas this did not occur in broods with lower than precise sex ratios. The hypothesized occurrence of strict local mate competition in P. pyralophagus was supported also by observations that: (i) offspring brood sex ratios were independent of maternal brood sex ratios and number of parental females concurrently allocating offspring to a group of hosts, and; (ii) the rate of superparasitism under no-choice conditions was low (~20%), suggesting that rates of outbreeding in the field are low. Other results suggested that fitness in P. pyralophaguswas correlated with adult size; longevity and reproductive capacity both increased with adult size in males and females. However, adult size may be more important for females than for males because the differences in reproductive capacity between the largest and smallest individuals was up to 7.3 times greater in females versus <2 times in males.
Effects of a diet deficient in the B complex vitamins on infectivity, growth and distribution of Echinostoma caproni in ICR mice
Authors: Simpkins H.L. , Fried B.
Published: March 2011

The effects of a diet deficient in the B vitamins on infectivity, growth, and distribution of Echinostoma caproni in ICR mice were studied. The vitamin-deficient diet (experimental) was isocaloric to the control diet but lacked the B vitamins. Thirty-six female, 6- to 8-week-old ICR mice were each infected with 25 metacercarial cysts. From the day of infection to the day of necropsy, 18 mice were fed the experimental diet and the remaining mice received the control diet. Equal numbers of experimental and control mice were necropsied at 2, 3 and 4 weeks postinfection (p.i.). Mice on the experimental diet showed a significant loss in body weight between 2 and 4 weeks p.i. There was no significant difference in worm recovery at 2 to 4 weeks p.i. from mice on either diet. Worms from hosts on the experimental diet were more dispersed and located more posteriad in the small intestine than those from mice on the control diet. Worm dry weight was significantly less in hosts on the experimental diet at all weeks p.i. compared with that of hosts on the control diet. The body area of worms on the experimental diet was significantly less at 2 and 3 weeks p.i. than that of worms on the control diet. An isocaloric diet deficient in the B vitamins had a detrimental effect on the growth of E. caproni in ICR mice.
Relationship between three intensity levels of Toxocara canis larvae in the brain and effects on exploration, anxiety, learning and memory in the murine host
Authors: Cox D.M. , Holland C.V.
Published: March 2011

Outbred LACA mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4×250 ova) doses of Toxocara canis ova and the effect of infection was examined with respect to the number of larvae recovered from the brain and their behaviour. Recovery of larvae from the brain was generally low with the % recovery expressed in terms of the total dose administered being highest for the 3000 dose (6.1%) and 1000 dose (6%), followed by the 100 (4.4%) and trickle (3.5%) doses. The variation in larval recoveries was large between individual mice receiving similar doses. The level of infection in the brain was lower in mice receiving a multiple as opposed to an equivalent single dose of ova. Mice were then divided into three larval intensity groupings based upon the number of larvae recovered from their brain. The ranges for the groups were as follows: low intensity group, 0–15 larvae; moderate intensity group, 27–55 larvae; high intensity group, 66–557 larvae. Three behavioural tests were carried out on control and infected mice. Exploration and response to novelty was examined using a ‘T’ maze and learning was investigated by means of a water-finding task. Anxiety was measured using an elevated plus maze apparatus. Infected mice were less explorative and less responsive to novelty in the ‘T’ maze and this was particularly pronounced for the heavily infected mice. In the elevated plus maze, infected mice displayed reduced levels of anxiety to aversive and exposed areas of the maze, particularly in the case of the moderate and high intensity mice. There was evidence for impaired learning ability in the water task apparatus for moderate and high intensity mice. In general, the effects of infection on behaviour were more pronounced in the moderate and high intensity groups compared to the low intensity group.
Seasonal population dynamics of Neoechinorhynchus qinghaiensis in the carp, Gymnocypris przewalskii przewalskii, from Qinghai Lake, China
Authors: Tingbao Yang , Xianghua Liao
Published: March 2011

Studies on the seasonal population dynamics of Neoechinorhynchus qinghaiensis (Acanthocephala: Neoechinorhynchidae) in its fish host Gymnocypris przewalskii przewalskii in the Qinghai Lake, China, were carried out with samples taken in May 1991, August 1992, November 1992 and February 1993. Prevalences were higher than 44% in all seasons. The mean intensity of infection was above 124 worms per fish. The maximum intensity of worms recovered from a single fish was 1402 in the autumn of 1992. Differences in the mean abundance, mean intensity and prevalence are not statistically significant relative to season and this is likely to be related to the stable temperatures recorded at the bottom of Qinghai Lake. Over-dispersed distributions of N. qinghaiensis in the host population, due to heterogeneity and feeding habits, were observed in all seasons. The size composition of both sexes of N. qinghaiensis showed males to be less than 3.5 mm and females between 0.5 and 4.25 mm, with the main recruitment phase in the worm populations occurring in the autumn, extending through winter and spring with the lowest recruitment occurring in the summer. The maturation and copulation of worms were mainly focused in the summer season. The sex ratio of female to male was both high in winter (1.51:1) and spring (1.48:1). The higher proportion of females and the change in the worm sex ratio in winter can be attributed to the reduced longevity of male worms. As immature male worms exhibit a higher proportion of the worm population than females in all seasons, further studies are needed to determine if such a situation compensates for the shorter life span of males.
Experimental Oesophagostomum bifurcum in monkeys
Authors: Eberhard M.L. , Kovacs-Nace E. , Blotkamp J. , Verwij J.J. , Asigri V.A.A. , Polderman A.M.
Published: March 2011

Oesophagostomum bifurcum larvae, cultured from human stools collected in northern Ghana, were used to establish experimental infections in monkeys. A patent infection was established in a rhesus monkey (Macaca mulatta) and this infection was used to generate larvae to inoculate additional monkeys. In all, 17 animals were inoculated. Thirteen of 15 animals developed antibodies to the infection between 19 and 62 days post inoculation (PI); two animals had a positive response before inoculation. Four of ten animals developed patent infections between 88 and 134 days and passed eggs in the faeces. Egg shedding was consistent in only one animal, but at low levels of one or two eggs per 2 mg direct smear, and extended over a 400 day period. In the other three animals, egg shedding was sporadic and of only 2–4 weeks duration. In seven animals necropsied between 19 and 22 days PI, one to 17 early fourth-stage larvae were recovered from nodules in the bowel wall; in an eighth animal examined at 314 days, six immature adult worms (early fifth stage) were recovered from nodules in the bowel wall. The morphological features and growth of these recovered larvae are described. Three animals were inoculated with larvae that had been dried for one week at 28°C; two animals began shedding eggs at 128 and 134 days PI, respectively. The present results suggest that the parasite obtained from humans is poorly adapted to lower primate hosts, and supports the concept that Oesophagostomum bifurcum found in humans and monkeys in the same geographical region of northern Ghana and Togo are distinct and that the infections in humans are not likely to represent zoonotic infections acquired from monkeys.
Purification and partial characterization of proteinase activity in eggs of Dicrocoelium dendriticum
Authors: Giménez-Pardo C. , Armas-Serra C. de , Rodríguez-Caabeiro F.
Published: March 2011

A preliminary purification has been carried out by continuous elution electrophoresis of a 49.5 kDa protease of crude extracts from Dicrocoelium dendriticum eggs. The enzyme showed a high capacity to degrade the collagen derivative azocoll at acidic pH. Although it is necessary to carry out further experiments to confirm any physiological role, this protease could be implicated in penetration mechanisms.
Redescription of Steinernema longicaudum Shen & Wang (Nematoda: Steinernematidae); geographic distribution and phenotypic variation between allopatric populations
Authors: Stock S.P. , Heng J. , Hunt D.J. , Reid A.P. , Shen X. , Choo H.Y.
Published: March 2011

Steinernema longicaudum Shen & Wang is redescribed based on a comparative morphological study of specimens from the type isolate from China, and two other isolates recovered from Korea and the USA. For the first and second generation female, the location of the vulva, shape of the vulval lips, and shape and length of the tail were newly observed diagnostic characters. A more detailed description of the morphology of the male spicules and gubernaculum, and the arrangement of the genital papillae is included. A description, based on scanning electron microscopy observations, of the lateral field pattern of the third-stage infective juveniles is also provided. Additionally, restriction fragment length polymorphism profiles based on the internal transcribed spacer region, and cross-breeding tests supplement the description of this species.
Helminth communities in eels Anguilla anguilla from Adriatic coastal lagoons in Italy
Authors: Di Cave D. , Berrilli F. , De Liberato C. , Orecchia P. , Kennedy C.R.
Published: March 2011

The composition and diversity of the total and intestinal component and infra-communities were determined in eels Anguilla anguilla from three shallow lagoons on the Adriatic coast of Italy to determine whether the helminth communities would differ in composition and structure from those in eels from lagoons on the Tyrrhenian coast. The lagoons differed in respect of their management regimes and the extent of freshwater influx. Both freshwater and marine species of helminths were found in the eels in all three lagoons, but the freshwater component was richer in Valle Figheri. A suite of three digenean eel specialist species occurred in all three lagoons, of which any two members dominated each community. This conferred a high degree of similarity between the communities of the three lagoons. The same three species also dominated helminth communities in eels in lagoons along the Tyrrhenian coast of Italy, and compositional similarity levels were similar within and between western and eastern groups. Species richness was higher in the component communities of the eels of the Adriatic lagoons when compared to the Tyrrhenian ones, but diversity and dominance indices were of a similar order of magnitude and range. Intestinal helminth communities were richer and more diverse in two of the Adriatic lagoons because the proportion of eels with zero or one helminth species was, unusually, in the minority. It was nevertheless concluded that infracommunity structure was similar in eels from both western and eastern lagoons and that the hypothesis that it would differ in Adriatic lagoons could not be supported. The findings provide further evidence of the similarity in composition and structure of helminth communities in eels from coastal lagoons throughout Europe.
The electrical characterization and response to hydrogen of Schottky diodes with a resistive metal electrode—rectifying an oversight in Schottky diode investigation
Authors: Dawson P , Feng L , Penate-Quesada L , Mitra J , Hill G
Published: March 2011

Schottky-barrier structures with a resistive metal electrode are examined using the 4-point probe method where the probes are connected to the metal electrode only. The observation of a significant decrease in resistance with increasing temperature (over a range of ∼100 K) in the diode resistance–temperature (R
D–T) characteristic is considered due to charge carrier confinement to the metal electrode at low temperature (high resistance), with the semiconductor progressively opening up as a parallel current carrying channel (low resistance) with increasing temperature due to increasing thermionic emission across the barrier. A simple model is constructed, based on thermionic emission at quasi-zero bias, that generates good fits to the experimental data. The negative differential resistance (NDR) region in the R
D–T characteristic is a general effect and is demonstrated across a broad temperature range for a variety of Schottky structures grown on Si-, GaAs- and InP-substrates. In addition the NDR effect is harnessed in micro-scaled Pd/n-InP devices for the detection of low levels of hydrogen in an ambient atmosphere of nitrogen.
Physical properties of Co/n-Ge Schottky contacts
Authors: Lajaunie L , David M L , Barbot J F
Published: March 2011

To investigate the role of the interface state on the physical properties of Schottky contacts, Co/n-Ge Schottky diodes that have undergone various cleaning methods (HF etching and in situ thermal cleaning) were studied by transmission electron microscopy, deep-level transient spectroscopy and by a detailed analysis of the temperature dependence of the characteristics of the diodes. It is shown that Schottky barrier height characteristics are sensitive to the nature of the interface. The strongest Fermi level (FL) pinning and the highest spatial inhomogeneities are observed for intimate metal/semiconductor contacts. The presence of a thin oxide interlayer, even of Ge native oxide, allows the FL to be released towards the conduction band and leads to more homogeneous contacts. Finally, our results suggest that a pure GeO2 oxide interlayer should present a better depinning efficiency than the native Ge oxide.
Proton magnetic resonance study of diamond nanoparticles decorated by transition metal ions
Authors: Panich A M , Altman A , Shames A I , Osipov V Yu , Aleksenskiy A E , Vul' A Ya
Published: March 2011

We report on a 1H NMR study of diamond nanoparticles decorated by copper and cobalt. Increase in the 1H relaxation rate under decoration results from the interactions of hydrogen nuclear spins of the surface hydrocarbon and hydroxyl groups with paramagnetic copper and cobalt ions. This finding reveals the appearance of paramagnetic Cu2+ or Co2+ ions on the detonation nanodiamond (DND) surface rather than as a separate phase, which is consistent with the 13C NMR data of the same samples. Our results shed light on the mechanism of ion incorporation. A topological model for relative position of paramagnetic Cu2+ or Co2+ ions and hydrogen atoms on the DND surface is suggested. An application of the studied nanomaterials in the field of biomedicine is discussed.
Orientation growth and electrical properties of ZnO/BaTiO3 heterostructures on silicon substrates by chemical solution deposition
Authors: Wei X H , Yue M Q , Zhu J
Published: March 2011

Metal–ferroelectric–semiconductor (MFS) structures based on ZnO/BaTiO3 were fabricated by chemical solution deposition (CSD). The microstructure of the heterostructures was characterized by x-ray diffraction and atomic force microscopy. Both ZnO and BaTiO3 layers were found to be c-axial oriented on LaNiO3-coated silicon substrates. The morphology revealed good interface quality with root-mean-square values of about 10 nm. Compared with BaTiO3 ferroelectric thin films, the capacitance–voltage curves of Pt/ZnO/BaTiO3/LaNiO3 heterostructures exhibited a counterclockwise hysteresis loop for the MFS capacitor confirming the ferroelectric nature integrated with an n-type semiconductor. The memory windows increased and then reduced as the frequency changed from 100 kHz to 1 MHz, which can be explained by a frequency-dependent coercive field and electron injection behaviour. The current–voltage curves of ZnO/BaTiO3 heterostructure showed a good insulating characteristic. These results suggested that ZnO/BaTiO3 MFS heterostructures by CSD can be used for memory devices.
Growing imbedded Ni3C-rich layer with sharp interfaces by means of ion beam mixing of C/Ni layers
Authors: Barna Árpád , Kotis László , Lábár János , Sulyok Attila , Tóth Attila L , Menyhárd Miklós , Panjan Peter
Published: March 2011

C/Ni bilayers of various layer thicknesses (20–40 nm) were ion bombarded using Ga+ and Ni+ projectiles of energies 20 and 30 keV. Ion bombardment resulted in the growth of a Ni3C rich layer with the following features: (a) sharp carbon/Ni3C rich layer interface, (b) the amount of Ni3C produced by the irradiation proportional to the square root of the fluence and dependent on the type of projectile, (c) good correlation between the distribution of vacancies produced by the ion bombardment and the distribution of Ni3C. The formation of the metastable Ni3C compound was explained by a vacancy-assisted process. The sharp interface is the consequence of a relaxation process removing the intermixed Ni from the carbon layer. The square root of fluence dependence of the thickness of the Ni3C-rich layer can be explained by a usual diffusion equation considering moving boundaries.
Scattering by coupled resonating elements in air
Authors: Krynkin Anton , Umnova Olga , Chong Alvin Y B , Taherzadeh Shahram , Attenborough Keith
Published: March 2011

Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low-frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the openings are much smaller than the wavelength. The problem of scattering by a finite periodic array of such coupled resonators in air is solved using multiple scattering techniques. The resulting model predicts band-gap effects resulting from the resonances of the individual composite scatterers below the first Bragg frequency. Predictions and data confirm that use of coupled resonators results in substantial insertion loss peaks related to the resonances within the concentric configuration. In addition, for both scattering problems experimental data, predictions of the analytical approach and predictions of the equivalent fluid layer approximations are compared in the low-frequency interval.
Molecular free path distribution in rarefied gases
Authors: Dongari Nishanth , Zhang Yonghao , Reese Jason M
Published: March 2011

We present the results of investigations into the distribution of molecular free paths in rarefied gases using molecular dynamics simulations. Our tests on a range of different gas densities and confinements (unbounded, single bounding wall and parallel bounding walls) indicate that the molecules perform Lévy-type flights, irrespective of the presence of a bounding wall. The free paths most closely follow a power-law distribution. Simulations of gases confined by planar surfaces indicate that the local molecular mean free path varies sharply close to a solid surface. These results may yield new insight into diffusive transport in rarefied gases, in particular, the constitutive behaviour of gas flows in micro- and nanoscale devices.
The scattering of a cylindrical invisibility cloak: reduced parameters and optimization
Authors: Peng L , Ran L , Mortensen N A
Published: March 2011

We investigate the scattering of 2D cylindrical invisibility cloaks with simplified constitutive parameters with the assistance of scattering coefficients. We show that the scattering of the cloaks originates not only from the boundary conditions but also from the spatial variation of the component of permittivity/permeability. According to our formulation, we propose some restrictions to the invisibility cloak in order to minimize its scattering after the simplification has taken place. With our theoretical analysis, it is possible to design a simplified cloak using some peculiar composites such as photonic crystals which mimic an effective refractive index landscape rather than offering effective constitutives, meanwhile cancelling the scattering from the inner and outer boundaries.