bluuebunny/crossref_metadata_2025 huggingface dataset:
Force detected electron spin resonance at 94GHz
Authors: Cruickshank Paul A. S. , Smith Graham M.
Published: January 2007

Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins, and it offers both extremely high absolute sensitivity and high spatial imaging resolution. However, compared to conventional induction mode ESR the technique also has a comparatively poor concentration sensitivity and it introduces complications in interpreting and combining both spectroscopy and imaging. One method to improve both sensitivity and spectral resolution is to operate in high magnetic fields in order to increase the sample magnetization and g-factor resolution. In this article we present FDESR measurements on the organic conductor (fluoranthene)2PF6 at 3.2T, with a corresponding millimeter-wave frequency of 93.5GHz, which we believe are the highest field results for FDESR reported in the literature to date. A magnet-on-cantilever approach was used, with a high-anisotropy microwave ferrite as the gradient source and employing cyclic saturation to modulate the magnetization at the cantilever fundamental frequency.
Turbulent impulsive magnetic energy release from electron scale reconnection
Authors: Horton W. , Kim J.-H. , Militello F. , Ottaviani M.
Published: January 2007

Magnetic reconnection may occur as bursts of nonlinear plasma dynamics on the electron collisionless skin length scale de=c∕ωpe, during which a large fraction of the magnetic energy is converted to plasma thermal energy and plasma flow energy. An example of such a bursty energy release event is given with a simple set of electron Hall equations. The energization mechanism is the cross-field compression of the electron gas between interacting magnetic islands. The electron energization appears to be consistent with the rapid electron energy flux changes measured by the Cluster spacecraft crossing thin current sheets at −17RE in the geotail. The analysis is relevant to planned spacecraft missions for measuring electron scale magnetic reconnection events in the geomagnetic tail.
Local electronic and optical behaviors of a-plane GaN grown via epitaxial lateral overgrowth
Authors: Moore J. C. , Kasliwal V. , Baski A. A. , Ni X. , Özgür Ü. , Morkoç H.
Published: January 2007

Conductive atomic force microscopy and near-field optical microscopy (NSOM) were used to study the morphology, conduction, and optical properties of a-plane GaN films grown via epitaxial lateral overgrowth (ELO) by metal organic chemical vapor deposition. The AFM images for the coalesced ELO films show undulations, where the window regions appear as depressions with a high density of surface pits. At reverse bias below 12V, very low uniform conduction (2pA) is seen in the window regions. Above 20V, a lower-quality sample shows localized sites inside the window regions with significant leakage, indicating a correlation between the presence of surface pits and leakage sites. Room temperature NSOM studies explicitly showed enhanced optical quality in the wing regions of the overgrown GaN due to a reduced density of dislocations, with the wings and the windows clearly discernible from near-field photoluminescence mapping.
Reversible exchange bias and uncompensated magnetization in FexNi1−xF2∕Co bilayers
Authors: Cheon Miyeon , Liu Zhongyuan , Lederman David
Published: January 2007

The exchange bias of epitaxial (110) FexNi1−xF2/polycrystalline Co bilayers was studied. FexNi1−xF2 is an antiferromagnet with a tunable magnetic anisotropy. A large uncompensated magnetization was observed in the hysteresis loops and its sign was correlated with the sign of the exchange bias. The exchange bias as well as the uncompensated magnetization could be reversed at low temperatures by applying large external fields as a result of the weak magnetic anisotropy of the antiferromagnet. Micromagnetic calculations support the authors’ interpretation of the experimental data. This mechanism is expected to be valid for a wide variety of systems.
Coulomb peak shifts under terahertz-wave irradiation in carbon nanotube single-electron transistors
Authors: Fuse T. , Kawano Y. , Suzuki M. , Aoyagi Y. , Ishibashi K.
Published: January 2007

The authors have studied the effect of terahertz irradiation on single-electron transistors (SETs) based on single-wall carbon nanotubes, and have observed that the radiation generates Coulomb peak shifts. Time-resolved measurements of the terahertz response have revealed that the peak-shift signal has very long time constants, measured in seconds, and that the time trace of the signal after the terahertz irradiation is turned off deviates from a single-exponential curve. These experimental results suggest that the terahertz irradiation causes a charging process in trap states in the close vicinity of the SET, leading to a change in its effective gate voltage.
High-mobility two-dimensional electron gas in InAlAs∕InAs heterostructures grown on virtual InAs substrates by molecular-beam epitaxy
Authors: Lin Y. , Carlin J. A. , Arehart A. R. , Carlin A. M. , Ringel S. A.
Published: January 2007

In 0.8 Al 0.2 As ∕ In As heterostructures were grown on virtual InAs substrates consisting of a relaxed InAsyP1−y step-graded buffer grown on InP by molecular-beam epitaxy. Hall measurements revealed the presence of a high-mobility two-dimensional electron gas within the relaxed InAs layer, with a peak electron mobility of 133000cm2∕Vs at 25K. In contrast, identical InAlAs∕InAs heterostructures grown directly on InAs buffers on InP showed only bulk transport characteristics. A combination of transport modeling and electron microscopy demonstrates that reduced dislocation scattering in the channel region is responsible for observing the two-dimensional transport within the relaxed InAs on graded InAsP. These results demonstrate the potential of achieving ultrahigh-speed InAs based high electron mobility transistors using relaxed, virtual InAs substrates on InP.
Nonvolatile switching characteristics of laser-ablated Ge2Sb2Te5 nanoparticles for phase-change memory applications
Authors: Suh Dong-Seok , Lee Eunhye , Kim Kijoon H. P. , Noh Jin-Seo , Shin Woong-Chul , Kang Youn-Seon , Kim Cheolkyu , Khang Yoonho , Yoon H. R. , Jo W.
Published: January 2007

Electrical characteristics of Ge2Sb2Te5 (GST) nanoparticles have been examined for a phase-change memory applications. The GST nanoparticles were generated by in situ pulsed laser ablation and their crystal structure formation was confirmed [H. R. Yoon et al., J. Non-Cryst. Solids 351, 3430 (2005)]. A stacked structure of the GST nanoparticles with 10nm of average diameter shows reversible nonvolatile switching characteristics between a high resistance state and a low resistance state as in the phase-change memory consisting of bulk GST thin film. Experimental results indicate that it is highly probable to test scaling issues of the phase-change memory with well-defined GST nanoparticles.
Tensile mechanical behavior of hollow and filled carbon nanotubes under tension or combined tension-torsion
Authors: Jeong Byeong-Woo , Lim Jang-Keun , Sinnott Susan B.
Published: January 2007

The tensile mechanical behavior of hollow and filled single-walled carbon nanotubes under tension or combined tension-torsion is examined using classical molecular dynamics simulations. These simulations indicate that the tensile strength under combined tension-torsion can be increased by filling the carbon nanotubes, and the amount of this increase depends on the kind of filling material. They also predict that the tensile strength under combined tension-torsion decreases linearly under applied torsion. The tensile strength can be modified by adjusting the system temperature and through chemical functionalization to the carbon nanotube walls.
Sc modified multiferroic BiFeO3 thin films prepared through a sol-gel process
Authors: Shannigrahi S. R. , Huang A. , Chandrasekhar N. , Tripathy D. , Adeyeye A. O.
Published: January 2007

Multiferroic thin films with the general formula BiFe1−xScxO3 (x=0.0, 0.1, 0.3, and 0.5mol%) (BFS) were synthesized on Pt∕Ti∕SiO2∕Si substrates through a sol-gel deposition method. From the x-ray diffraction (XRD) analysis, it was observed that the unit cell volume increased upon Sc doping up to 0.3mol%. Impure phase appeared for the BFS (Sc: 0.5mol%) films. Leakage current, ferroelectric, and magnetic properties were also found to improve for Sc doping up to 0.3mol%. Room temperature magnetic coercive field for in-plane orientation of films showed the lowest value for BFS (Sc: 0.3mol%) films, which indicates that BFS (Sc: 0.3mol%) films were more magnetically soft. Room temperature value of the magnetodielectric effect in the presence of magnetic field of 8kOe was found to have maximum of 3.36% for the BFS (Sc: 0.3mol%) films. From the x-ray photoelectron spectroscopy measurements, it was observed that the Fe has mixed valency states of 2+ and 3+. The ratio of Fe2+ and Fe3+ was found to decrease slightly in BFS (Sc: 0.3mol%) films. The improved leakage current and M-H loops support the authors’ observation.
Efficient plastic scintillators utilizing phosphorescent dopants
Authors: Campbell I. H. , Crone B. K.
Published: January 2007

The authors demonstrate improved light yield from plastic scintillators utilizing a phosphorescent dopant to collect both singlet and triplet excitations created by ionizing radiation. They specifically considered poly(vinyltoluene) and poly(9-vinylcarbazole) doped with an Ir phosphor. They present the spectral, temporal, and integrated yield responses as a function of dopant concentration to pulses of 10keV electrons. Both doped plastics yield a maximum light output of ∼200% of anthracene with decay times <850ns. High light yield was obtained for Ir element fractions up to ∼10wt%, implying that these scintillators may be useful for gamma detection.
Realization of a classical counterpart of a scalable design for adiabatic quantum computation
Authors: Zakosarenko V. , Bondarenko N. , van der Ploeg S. H. W. , Izmalkov A. , Linzen S. , Kunert J. , Grajcar M. , Il’ichev E. , Meyer H.-G.
Published: January 2007

The authors implement a classical counterpart of a scalable design for adiabatic quantum computation. The key element of this design is a coupler providing controllable coupling between two bistable elements (in our case superconducting rings with a single Josephson junction playing the role of a classical counterpart of superconducting flux qubits). The coupler is also a superconducting ring with a single Josephson junction that operates in the nonhysteretic mode with a screening parameter of about 0.9. The flux coupling between two bistable rings can be controlled by changing the magnetic flux through the coupler. Since the coupling amplitude is proportional to the derivative of the coupler’s current-flux relation, the coupling can be tuned from ferromagnetic to antiferromagnetic. In between the coupling can also be switched off.
Carbon nanotubes grown on In2O3:Sn glass as large area electrodes for organic photovoltaics
Authors: Miller Anthony J. , Hatton Ross A. , Chen G. Y. , Silva S. Ravi P.
Published: January 2007

The authors report the growth of multiwall carbon nanotubes directly onto indium tin oxide glass via chemical vapor deposition as large area semitransparent electrodes for organic solar cell applications. The rate of nanotube growth on this ternary oxide is greatly reduced as compared to that of silicon dioxide and glass substrates enabling a high degree of control over nanotube height. The strong potential of this nanostructured semitransparent substrate as an interpenetrating hole-extracting electrode in bulk-heterojunction organic solar cells is also demonstrated.
Polarization insensitive all-fiber mode-lockers functioned by carbon nanotubes deposited onto tapered fibers
Authors: Song Yong-Won , Morimune Keiyo , Set Sze Y. , Yamashita Shinji
Published: January 2007

The authors demonstrate a nonblocked all-fiber mode locker operated by the interaction of carbon nanotubes with the evanescent field of propagating light in a tapered fiber. Symmetric cross section of the device with the randomly oriented nanotubes guarantees the polarization insensitive operation of the pulse formation. In order to minimize the scattering, the carbon nanotubes are deposited within a designed area around the tapered waist. The demonstrated passively pulsed laser has the repetition rate of 7.3MHz and the pulse width of 829fs.
Observation of Brillouin zone folding in photonic crystal slab waveguides possessing a superlattice pattern
Authors: Neff Curtis W. , Yamashita Tsuyoshi , Summers Christopher J.
Published: January 2007

The optical properties of superlattice photonic crystal (PC) patterns in two-dimensional slab waveguides were investigated using coupled-resonance angular dependent reflectivity measurements. Additional features were found in the superlattice PC spectra in comparison to that of the triangular lattice, indicating Brillouin zone folding (BZF) due to the larger unit cell and reduced symmetry of the superlattice. Calculated band structures corroborate these measurements and confirm the BZF effect which was shown to extract portions of the triangular lattice guided bands into the waveguide radiating regime, making the dielectric bands excitable by an out-of-plane source.
Electrical polarization of nuclear spins in a breakdown regime of quantum Hall effect
Authors: Kawamura M. , Takahashi H. , Sugihara K. , Masubuchi S. , Hamaya K. , Machida T.
Published: January 2007

The authors have developed a method for electrical polarization of nuclear spins in quantum Hall systems. In a breakdown regime of odd-integer quantum Hall effect (QHE), excitation of electrons to the upper Landau subband with opposite spin polarity dynamically polarizes nuclear spins through the hyperfine interaction. The polarized nuclear spins in turn accelerate the QHE breakdown, leading to hysteretic voltage-current characteristics of the quantum Hall conductor.
Surface enhancement of soft-mode transformation in Ni2MnGa
Authors: Landmesser G. , Klemradt U. , Johnson R. L. , Finlayson T. R.
Published: January 2007

Ni 2 Mn Ga exhibits both shape memory behavior, owing to a diffusionless structural transformation, and ferromagnetism, leading to magnetic-field based actuator applications. The current interest in highly miniaturized mechanical devices raises the question whether the structural phase transformations of Ni2MnGa are affected by the presence of interfaces. Thermal diffuse scattering of x-rays from the soft phonon mode which drives the transformation was analyzed for depths from 3.5nmto6.4μm beneath a clean (001) surface. The authors find an enhancement of the transition temperature by about 15K in the near-surface region, but no evidence for a change of the soft-mode polarization.
Zn
Ir
2
O
4
, a p-type transparent oxide semiconductor in the class of spinel zinc-d6-transition metal oxide
Authors: Dekkers Matthijn , Rijnders Guus , Blank Dave H. A.
Published: January 2007

The authors report on the growth of spinel ZnM(d6)2O4 (M=Co, Rh, and Ir), a p-type wide band gap semiconductor by pulsed laser deposition. The band gap of these compounds is determined by the ligand field splitting in the subbands of the metallic d6 cation. Photoemission spectroscopy revealed that the valence band maximum is composed of occupied t2g6 states. The observed band gap is increasing for higher quantum numbers, being as large as ∼3eV for ZnIr2O4, which is expected from theoretical predictions. Grown in polycrystalline phase, films of these materials display high conductivity, well above 2Scm−1.
Crystal orientation dependence of the dielectric properties for epitaxial BaZr0.15Ti0.85O3 thin films
Authors: Miao J. , Yuan J. , Wu H. , Yang S. B. , Xu B. , Cao L. X. , Zhao B. R.
Published: January 2007

Epitaxial Ba0.15Zr0.85TiO3 (BZT) ferroelectric thin films with (001), (011), and (111) orientations were, respectively, grown on La0.67Sr0.33MnO3 (LSMO) buffered LaAlO3 substrates by pulsed laser deposition method. The dc electric-field dependence of permittivity and dielectric loss of (001)-, (011)-, and (111)-oriented BZT/LSMO heterostructures obeys the Johnson formula, and the ac electric-field dependence of that obeys the Rayleigh law under the subswitching field region. The anisotropic dielectric properties are attributed to the higher mobility of the charge carriers, the concentration of mobile interfacial domain walls, and boundaries in the (111)-oriental films than in the (110)- and (100)-oriented films.
Odour and visual cues utilised by German yellowjackets (Vespula germanica) while relocating protein or carbohydrate resources
Authors: Moreyra Sabrina , D'Adamo Paola , Lozada Mariana
Published: January 2007

Foragers of Vespula germanica (Fab.) return to a food source that has not been depleted. In this work we investigate the utilisation of olfactory and visual cues by these foragers for relocating a specific source location. We trained wasp foragers to feed on a dish with either honey or meat. At the testing phase, we analysed searching and landing behaviour over three cues: the original feeding site, an unscented model of the food, and a container from which food odours emanated. We compared the responses of the foragers to the three cues and evaluated the effect of bait type with which wasps were trained. We found that landing responses are elicited mainly by odour cues in both protein- and carbohydrate-trained wasps. However, the type of food that wasps are exploiting influences their searching behaviour, as the number of hovers over the visual cue was higher when wasps were trained with carbohydrates whereas the number of hovers over the original feeding site was higher when wasps were trained with proteins.
Mechanisms underlying the resistance to diet-induced obesity in germ-free mice
Authors: Bäckhed Fredrik , Manchester Jill K. , Semenkovich Clay F. , Gordon Jeffrey I.
Published: January 2007

The trillions of microbes that colonize our adult intestines function collectively as a metabolic organ that communicates with, and complements, our own human metabolic apparatus. Given the worldwide epidemic in obesity, there is interest in how interactions between human and microbial metabolomes may affect our energy balance. Here we report that, in contrast to mice with a gut microbiota, germ-free (GF) animals are protected against the obesity that develops after consuming a Western-style, high-fat, sugar-rich diet. Their persistently lean phenotype is associated with increased skeletal muscle and liver levels of phosphorylated AMP-activated protein kinase (AMPK) and its downstream targets involved in fatty acid oxidation (acetylCoA carboxylase; carnitine-palmitoyltransferase). Moreover, GF knockout mice lacking fasting-induced adipose factor (Fiaf), a circulating lipoprotein lipase inhibitor whose expression is normally selectively suppressed in the gut epithelium by the microbiota, are not protected from diet-induced obesity. Although GF
Fiaf
−/− animals exhibit similar levels of phosphorylated AMPK as their wild-type littermates in liver and gastrocnemius muscle, they have reduced expression of genes encoding the peroxisomal proliferator-activated receptor coactivator (Pgc-1α) and enzymes involved in fatty acid oxidation. Thus, GF animals are protected from diet-induced obesity by two complementary but independent mechanisms that result in increased fatty acid metabolism: (
i
) elevated levels of Fiaf, which induces Pgc-1α; and (
ii
) increased AMPK activity. Together, these findings support the notion that the gut microbiota can influence both sides of the energy balance equation, and underscore the importance of considering our metabolome in a supraorganismal context.
Cooperation and conflict in microbial biofilms
Authors: Xavier Joao B. , Foster Kevin R.
Published: January 2007

Biofilms, in which cells attach to surfaces and secrete slime (polymeric substances), are central to microbial life. Biofilms are often thought to require high levels of cooperation because extracellular polymeric substances are a shared resource produced by one cell that can be used by others. Here we examine this hypothesis by using a detailed individual-based simulation of a biofilm to investigate the outcome of evolutionary competitions between strains that differ in their level of polymer production. Our model includes a biochemical description of the carbon fluxes for growth and polymer production, and it explicitly calculates diffusion–reaction effects and the resulting solute gradients in the biofilm. An emergent property of these simple but realistic mechanistic assumptions is a strong evolutionary advantage to extracellular polymer production. Polymer secretion is altruistic to cells above a focal cell: it pushes later generations in their lineage up and out into better oxygen conditions, but it harms others; polymer production suffocates neighboring nonpolymer producers. This property, analogous to vertical growth in plants, suggests that polymer secretion provides a strong competitive advantage to cell lineages within mixed-genotype biofilms: global cooperation is not required. Our model fundamentally changes how biofilms are expected to respond to changing social conditions; the presence of multiple strains in a biofilm should promote rather than inhibit polymer secretion.
The crystal structure of the rhomboid peptidase from
Haemophilus influenzae
provides insight into intramembrane proteolysis
Authors: Lemieux M. Joanne , Fischer Sarah J. , Cherney Maia M. , Bateman Katherine S. , James Michael N. G.
Published: January 2007

Rhomboid peptidases are members of a family of regulated intramembrane peptidases that cleave the transmembrane segments of integral membrane proteins. Rhomboid peptidases have been shown to play a major role in developmental processes in
Drosophila
and in mitochondrial maintenance in yeast. Most recently, the function of rhomboid peptidases has been directly linked to apoptosis. We have solved the structure of the rhomboid peptidase from
Haemophilus influenzae
(hiGlpG) to 2.2-Å resolution. The phasing for the crystals of hiGlpG was provided mainly by molecular replacement, by using the coordinates of the
Escherichia coli
rhomboid (ecGlpG). The structural results on these rhomboid peptidases have allowed us to speculate on the catalytic mechanism of substrate cleavage in a membranous environment. We have identified the relative disposition of the nucleophilic serine to the general base/acid function of the conserved histidine. Modeling a tetrapeptide substrate in the context of the rhomboid structure reveals an oxyanion hole comprising the side chain of a second conserved histidine and the main-chain NH of the nucleophilic serine residue. In both hiGlpG and ecGlpG structures, a water molecule occupies this oxyanion hole.
Freshly excavated fossil bones are best for amplification of ancient DNA
Authors: Pruvost Mélanie , Schwarz Reinhard , Correia Virginia Bessa , Champlot Sophie , Braguier Séverine , Morel Nicolas , Fernandez-Jalvo Yolanda , Grange Thierry , Geigl Eva-Maria
Published: January 2007

Despite the enormous potential of analyses of ancient DNA for phylogeographic studies of past populations, the impact these analyses, most of which are performed with fossil samples from natural history museum collections, has been limited to some extent by the inefficient recovery of ancient genetic material. Here we show that the standard storage conditions and/or treatments of fossil bones in these collections can be detrimental to DNA survival. Using a quantitative paleogenetic analysis of 247 herbivore fossil bones up to 50,000 years old and originating from 60 different archeological and paleontological contexts, we demonstrate that freshly excavated and nontreated unwashed bones contain six times more DNA and yield twice as many authentic DNA sequences as bones treated with standard procedures. This effect was even more pronounced with bones from one Neolithic site, where only freshly excavated bones yielded results. Finally, we compared the DNA content in the fossil bones of one animal, a ≈3,200-year-old aurochs, excavated in two separate seasons 57 years apart. Whereas the washed museum-stored fossil bones did not permit any DNA amplification, all recently excavated bones yielded authentic aurochs sequences. We established that during the 57 years when the aurochs bones were stored in a collection, at least as much amplifiable DNA was lost as during the previous 3,200 years of burial. This result calls for a revision of the postexcavation treatment of fossil bones to better preserve the genetic heritage of past life forms.
Parasitic diseases of cats and dogs in the tropics.
Authors: Irwin P. , Traub R.
Published: January 2007

Parasitic, infectious and vector-borne diseases of humans and animals thrive in the typically hot and humid environment of the tropics. Many countries in these regions of the world remain underdeveloped with limited resources at their disposal to effectively combat the tremendous disease burdens borne by their human populations. Research, surveillance and control of veterinary diseases have been given priority only when those diseases have an impact on poverty alleviation or if they pose a significant zoonotic threat to the community. In some societies however, in Asia in particular, economic growth and increasing affluence has resulted in changing attitudes towards companion animal ownership and with this has come increasingly higher expectations and demands on veterinary surgeons for improved knowledge in canine and feline medicine and surgery. Yet despite expanding access to information technology, regionally pertinent information for veterinarians concerning the epidemiology, diagnosis and management of tropical diseases of these companion animals is scarce. The paper aims to redress this imbalance by providing, for the first time, a comprehensive review of the parasitic diseases of cats and dogs in the tropics. The first section discusses diseases and parasites of zoonotic importance; echinococcosis, toxocariasis, ancylostomiasis, the liver and intestinal flukes, gnathostomiasis, toxoplasmosis, leishmaniasis and American trypanosomiasis. In the second section the parasitic diseases of clinical importance for the animals themselves are considered, including babesiosis, dirofilariasis, hepatozoonosis, ectoparasitic diseases, angiostrongylosis and spirocercosis, with information provided on the diagnosis and treatment of these diseases.
Bovine protothecal mastitis: a review.
Authors: Rakesh Ranjan Rakesh Ranjan , Swarup D. Swarup D. , Patra R. C. , Nandi D. Nandi D.
Published: January 2007

Bovine mastitis is a multi-aetiological ailment that accounts for the immense economic losses due to fall in milk production and poor quality of milk as well as therapeutic expenditures. Bovine protothecal mastitis is caused by
Prototheca zopfii
and
P. wickerhamii
and has been reported in most of the countries of the world. Dirty environment and lack of hygiene in herd play a vital role in transmission of the malady. Faeces from infected cows transmit the organisms into environment. Age, stage of lactation, host's immune status and previous exposure to treatment as well as other ailments predispose the animal to the disease. Multiplication of the organisms in the mammary gland and regional lymph node results in damage of mammary parenchyma leading to fall in milk yield and, sometimes, drying of infected quarters. Organisms infrequently disseminate from the site of lesion to visceral organs. Though intense inflammatory reaction is not seen in protothecal mastitis, still induration, fibrotic hard udder, fall in milk yield with presence of clots in milk and increase in somatic cell count are commonly associated with algal mastitis. Diagnosis is usually accomplished by selective isolation and light microscopic demonstration of the organism, which can be further aided by carbohydrate and alcohol assimilation test, fluorescence microscopy, fine needle aspiration associated with electron microscopy or detection of antibodies by counter-flow electrophoresis. Poor sensitivity of the organism to the conventional antibiotics limits their use in treatment. Antifungals like nystatin, amphotericin, polymyxin, miconazole as well as levamisole tetramisole proved beneficial to some extent. Eradication of the pathogen from herd is a difficult and practically an impossible task, leaving only preventive measures as the resort for controlling the disease.
Nanotechnology potential in forest products  a US perspective.
Authors: Risbrudt C. D.
Published: January 2007

Nanotechnology has become recognized as a stimulus for innovation, involving new concepts across the standard scientific discipline lines, representing unexplored areas for discovery. Knowledge and innovation are being pursued in a substantially different manner, with substantial anticipated opportunities to be captured. Nanotechnology will enable many of the technological advances we need to achieve sustainable forestry in the US. This area of research holds much potential for significant improvements in forest products manufacturing processes and new and improved wood-based products.
Laser Spectroscopic Investigations of CaCl. II. Rotational Analysis of the B2Σ- X2Σ Transitions
Authors: L-E Berg  , L Klynning  , H Martin
Published: January 2007

Diatomic calcium chloride has been examined by means of laser excitation and fluorescence spectroscopy. A small resistance furnace and a c.w. Rhodamine 6G dye laser were used to produce the spectra. The absorption spectrum of CaCl was also recorded by using a 5 m Jarrel Ash spectrograph. The following rotational and vibrational constants of theB2Σ andX2Σ states have been derived (cm-1):

B2Σ+X2Σ+Te16 856.684(4)0.0ωe367.196(6)370.201(1)ωexe1.524(2)1.3732(1)ωeye8.6(2) × 10-39.3 × 10-3ωeze-3.8(2) × 10-4-4.8(2) × 10-4Be0.154 704(1)0.152 233αe8.835(3) × 10-47.92 × 10-4De1.1409(4) × 10-71.068 × 10-7γe-6.531(7) × 10-21.38 × 10-3γD1.36(6) × 10-70.0αγ-4.0(6) × 10-40.0

The figures in parentheses stand for one standard deviation in the last digit for the computed quantity.
Characterization and predictive discovery of evolutionarily conserved mammalian alternative promoters
Authors: Baek Daehyun , Davis Colleen , Ewing Brent , Gordon David , Green Phil
Published: January 2007

Recent studies suggest that surprisingly many mammalian genes have alternative promoters (APs); however, their biological roles, and the characteristics that distinguish them from single promoters (SPs), remain poorly understood. We constructed a large data set of evolutionarily conserved promoters, and used it to identify sequence features, functional associations, and expression patterns that differ by promoter type. The four promoter categories CpG-rich APs, CpG-poor APs, CpG-rich SPs, and CpG-poor SPs each show characteristic strengths and patterns of sequence conservation, frequencies of putative transcription-related motifs, and tissue and developmental stage expression preferences. APs display substantially higher sequence conservation than SPs and CpG-poor promoters than CpG-rich promoters. Among CpG-poor promoters, APs and SPs show sharply contrasting developmental stage preferences and TATA box frequencies. We developed a discriminator to computationally predict promoter type, verified its accuracy through experimental tests that incorporate a novel method for deconvolving mixed sequence traces, and used it to find several new APs. The discriminator predicts that almost half of all mammalian genes have evolutionarily conserved APs. This high frequency of APs, together with the strong purifying selection maintaining them, implies a crucial role in expanding the expression diversity of the mammalian genome.
Spurious counts and spurious results on haematology analysers: a review. Part II: white blood cells, red blood cells, haemoglobin, red cell indices and reticulocytes
Authors: ZANDECKI M. , GENEVIEVE F. , GERARD J. , GODON A.
Published: January 2007

Haematology analysers provide quick and accurate results in most situations. However, spurious results, related either to platelets (part I of this report) or to other parameters from the cell blood count (CBC) may be observed in several instances. Spuriously low white blood cell (WBC) counts may be observed because of agglutination in the presence of ethylenediamine tetra‐acetic acid (EDTA). Cryoglobulins, lipids, insufficiently lysed red blood cells (RBC), erythroblasts and platelet aggregates are common situations increasing WBC counts. In most of these instances flagging and/or an abnormal WBC differential scattergram will alert the operator. Several situations lead to abnormal haemoglobin measurement or to abnormal RBC count, including lipids, agglutinins, cryoglobulins and elevated WBC counts. Mean (red) cell volume (MCV) may be also subject to spurious determination, because of agglutinins, excess of glucose or salts and technological considerations. In turn, abnormality related to one measured parameter will lead to abnormal calculated RBC indices: mean cell haemoglobin content (MCHC) is certainly the most important RBC indices to consider, as it is as important as flags generated by the haematology analysers (HA) in alerting the user to a spurious result. In many circumstances, several of the measured parameters from CBC may be altered, and the discovery of a spurious change on one parameter frequently means that the validity of other parameters should be considered. Sensitive flags now allow the identification of several spurious counts, but only the most sophisticated HA have optimal flagging and more simple HA, especially those without a WBC differential scattergram, do not possess the same sensitivity for detecting anomalous results. Reticulocytes are integrated now into the CBC in many HA, and several situations may lead to abnormal counts.
The −35 sequence location and the Fis–sigma factor interface determine σS selectivity of the proP (P2) promoter in Escherichia coli
Authors: Typas Athanasios , Stella Stefano , Johnson Reid C. , Hengge Regine
Published: January 2007

The P2 promoter of proP, encoding a transporter for proline and glycine betaine in Escherichia coli, is a unique paradigm, where master regulators of different growth stages, Fis and σS (RpoS), collaborate to achieve promoter activation. It is also the only case described where Fis functions as class II transcriptional activator (centred at −41). Here we show that the degenerate −35 sequence, and the location of the Fis binding site, which forces a suboptimal 16 bp spacing between the −35 and −10 elements, allow only σS but not σ70 to function at proP (P2). Moreover, the interface between Fis and σS seems better suited to σS, due to a single residue difference between σS and σ70. Nevertheless, Fis can activate RNA polymerase containing σ70 at a proP (P2) promoter variant, in which a typical σ70−35 recognition sequence has been introduced at a 17 bp distance from the −10 hexamer. In summary, we elucidate the rules that govern sigma factor selectivity in the presence of a class II activator, provide new insight into transcriptional activation by Fis from this position, and clarify, why the proP (P2) promoter is precisely activated during a short time window of the growth cycle, when Fis and σS are both present.
Portal circulation aneurysms: Two case reviews
Authors: Perret WL , De Silva A , Elzarka A , Schelleman A
Published: January 2007

Venous aneurysms of the superior mesenteric vein and portal vein are an uncommon occurrence and often an incidental finding. They can also be associated with hepatocellular disease and portal hypertension. We present CT and ultrasound findings of these entities. The management of venous aneurysms is generally conservative with serial imaging.
Inguinal endometriosis attaching to the round ligament
Authors: Hagiwara Y , Hatori M , Moriya T , Terada Y , Yaegashi N , Ehara S , Kokubun S
Published: January 2007

We report a case of endometriosis in the right inguinal region, attached to the right round ligament in a 28‐year‐old woman. At the age of 20, laparoscopic left ovarian cystectomy and pelvic adhesiolysis for endometriosis was carried out. She noticed a right tender groin mass 7 months previously, and the tumour size fluctuated with the menstrual cycle. A poorly circumscribed elastic hard mass, measuring 3 cm in diameter, was palpated in her right inguinal region. Magnetic resonance imaging showed a 2.5 cm × 2.5 cm mass in the right inguinal canal and a 5.4 cm × 6.8 cm mass was seen in the left ovary. The mass enlarged during menstruation. The groin mass was removed, in addition to carrying out laparoscopic ovarian cystectomy. At operation, the groin mass was found to be in continuity with the round ligament of extraperitoneal portion. Histological diagnosis of endometriosis was made in both ovarian and inguinal tumours. After surgery, the pain disappeared completely. Worth mentioning is that MRI clearly showed the change of tumour size depending on the menstrual cycle, which aided in arriving at the correct diagnosis of endometriosis in an unusual location.
Characterization of strength properties of thin polycrystalline silicon films for MEMS applications
Authors: Boroch R. , Wiaranowski J. , Mueller‐Fiedler R. , Ebert M. , Bagdahn J.
Published: January 2007

The aim of this work is to characterize the strength properties of polycrystalline silicon (polysilicon) with the use of tensile and bending test specimens. The strength of thin polysilicon films with different geometry, size and stress concentrations has been measured and correlated with the effective size of the specimen and its stress distribution.

The test results are evaluated using a probabilistic strength approach based on the weakest link theory with the use of STAU software. The use of statistic methods of strength prediction of polysilicon test structures with a complex geometry and loading based on test values for standard material tests specimen has been evaluated.
Specimen aligning techniques in tensile and fatigue tests for thin films
Authors: KIM S.‐W. , OH C.‐S. , LEE H.‐J.
Published: January 2007

Measurements of the mechanical properties of a thin film are strongly influenced by the test procedures. The aim of this paper is to introduce specimen aligning techniques for tensile and fatigue tests with thin films. The calculated modulus for polycrystalline silicon can vary from 100 to 160 GPa according to the alignment condition and reaches a peak at the best alignment as determined from an extensive pre‐tensile test. The ‘modulus alignment method’ is utilized to ensure the specimen alignment before doing tensile and fatigue tests based on the fact that the better the alignment, the higher the modulus. In addition to that, a closed loop control scheme is applied during a fatigue test to maintain the constant load. An S–N curve for polysilicon film is obtained and compared with the results of other researchers.
Tourniquet use in childhood: a harmless procedure?
Authors: SINICINA INGA , BISE KARL , HETTERICH REINHARD , PANKRATZ HELMUT
Published: January 2007

Tourniquet ischemia is widely used in limb surgery in every age group. In adults, tourniquet‐related deep vein thrombosis and pulmonary embolism are recognized complications of tourniquet use. In healthy children, tourniquet‐associated alterations of blood clotting physiology are assumed to have no clinical impact. Antithrombotic prophylaxis is, therefore, recommended only in the presence of pertinent risk factors such as extensive surgery, congenital thrombophilia, prolonged immobilization, and indwelling central venous line, however, it is not practiced in obese, otherwise healthy children. We describe the first case of fatal pulmonary thromboembolism in an obese 12‐year and 3‐month old boy (body mass index 27.6 kg.m−2) following tourniquet‐deflation after minor surgery on the lower extremity.
Increased forearm blood flow in longstanding Type 1 diabetic patients without microvascular complications
Authors: Van Gurp P. J. , Lenders J. W. M. , Tack C. J.
Published: January 2007

Aims  According to the ‘haemodynamic hypothesis’, chronic hyperglycaemia induces an increase in tissue perfusion that predisposes to microangiopathy. We hypothesized that patients with longstanding diabetes mellitus (DM), who have not developed microvascular complications, would have normal tissue perfusion.

Methods  In six Type 1 diabetic patients (age 43.4 ± 1.1 years; DM duration 25.3 ± 2.6 years.; HbA1c 8.5 ± 0.7%), who had no evidence of microvascular complications, and six age‐ and gender‐matched healthy volunteers (Control) we measured haemodynamic parameters including forearm blood flow (FBF; plethysmography) and sympathetic tone, an important regulator of blood flow, by the combination of plasma sampling (catecholamine levels), microneurography and power spectral analysis of blood pressure and heart rate.

Results  FBF was increased in the diabetic compared with control subjects (4.8 ± 1.2 vs. 2.2 ± 0.3 ml/dl per min, P < 0.05) and forearm vascular resistance (FVR) was decreased (25 ± 6 and 43 ± 3 arbitrary units, P < 0.05). Heart rate was higher in diabetic subjects (77 ± 10 vs. 57 ± 2 beats/min, P < 0.05). All parameters of sympathetic tone were similar in diabetic and control subjects.

Conclusions  In patients with Type 1 diabetes, without signs of microvascular complications and with diabetes duration of > 20 years, skeletal muscle blood flow was increased while sympathetic tone was normal. These results suggest that increased blood flow does not inevitably lead to microvascular complications and challenge the hypothesis that it has a causative role in the pathophysiology of complications.
Can we identify adolescents at high risk for nephropathy before the development of microalbuminuria?
Authors: Dunger D. B. , Schwarze C. P. , Cooper J. D. , Widmer B. , Neil H. A. W. , Shield J. , Edge J. A. , Jones T. W. , Daneman D. , Dalton R. N.
Published: January 2007

Aims  To determine whether higher than average albumin excretion during early puberty identifies subjects who will subsequently develop microalbuminuria (MA) and clinical proteinuria.

Methods  Longitudinal data from the Oxford Regional Prospective Study of Childhood Diabetes (ORPS; n = 554, median duration of follow‐up 10 years; range 3.0–16.7) with assessment of albumin/creatinine ratios in three early morning urine samples collected annually. An albumin excretion phenotype was derived from longitudinal data, for each individual, defining deviation from the mean of regression models, including covariates gender, age, duration of diabetes and age at assessment. Tracking of the phenotypes was confirmed in a second independent cohort from Perth, Australia.

Results  The albumin excretion phenotype showed reasonable correlation between age 11–15 years and age 16–18 years in both cohorts, indicative of good ‘tracking’. In the ORPS cohort, tertiles of the albumin excretion phenotype at aged 11–15 years were predictive of subsequent risk for the development of MA. All of the subjects developing clinical proteinuria had an albumin excretion phenotype in the upper tertile or an HbA1c > 9% at aged 11–15 years.

Conclusions  Identification of adolescents at risk of diabetic nephropathy using an albumin excretion phenotype is feasible. When combined with elevated HbA1c, it may identify subjects for trial of early intervention with angiotensin‐converting enzyme inhibitors/angiotensin‐II receptor antagonists and statins to improve long‐term prognosis in these subjects where sustained improvement in glycaemic control may be difficult to achieve.
Middle cerebral artery dolichoectasia in a young woman with a previous stroke
Authors: Puca A. , Marchese E. , Esposito G. , Calcagni M. L. , Di Lazzaro V.
Published: January 2007

We observed a 32‐year‐old female who had suffered from a left hemisphere ischemic stroke with right hemiparesis at the age of seven. At that time, a CT scan demonstrated a left ischemic lesion in nucleo‐capsular region and a cerebral angiogram documented a complete occlusion of the supraclinoid segment of the internal carotid artery. When we observed the patient neurological examination demonstrated a moderate right brachio‐crural hemiparesis. A brain MRI showed an old ischemic lesion involving the left nucleo‐capsular and ‘flow voids’ suggestive for a vascular malformation in the left sylvian region. A cerebral rotational angiogram with 3‐D reconstructions demonstrated a dolichoectatic left middle cerebral artery with an unusual ‘corkscrew’ aspect. Middle cerebral artery dolichoectasia is a rare pathological condition that may manifest with a stroke. The patients with intracranial arterial dolichoectasia (IADE) are most often hypertensive elderly men, and, to the best of our knowledge, an ischemic stroke associated with IADE has never been reported in children.
The state of political priority for safe motherhood in Nigeria
Authors: Shiffman J , Okonofua FE
Published: January 2007

Achieving the ambitious maternal mortality reduction aims of the Millennium Development Goals will require more than generating sufficient donor support and carrying out appropriate medical interventions. It also will necessitate convincing governments in developing countries to give the cause political priority. The generation of political priority, however, is a subject that has received minimal research attention. In this article, we assess the state of political priority for maternal mortality reduction in Nigeria, which has more maternal deaths in childbirth than any country except India. We also identify challenges that advocates face in promoting priority. We find that after decades of neglect, a policy window has opened for safe motherhood in Nigeria, giving hope for future maternal mortality reduction. However, priority is as yet in its infancy, as advocates have yet to coalesce into a potent political force pushing the government to action. The case of Nigeria suggests that there is an urgent need for safe motherhood policy communities in countries with high maternal mortality to transform their moral and technical authority into political power, pushing policy‐makers to action. We offer a number of suggestions on how they may do so.
Pentraxin 3 in plasma and vaginal fluid in women with preterm delivery*
Authors: Assi F , Fruscio R , Bonardi C , Ghidini A , Allavena P , Mantovani A , Locatelli A
Published: January 2007

Objective  To investigate the role of pentraxin 3 (PTX3), an acute‐phase protein produced by cells of innate immunity in response to inflammatory signals, in spontaneous preterm delivery (PTD).

Design  Cohort study.

Setting  Department of Obstetrics and Gynecology of the University of Milano‐Bicocca.

Population  Forty‐six pregnant women with preterm rupture of membranes (n= 33) or preterm labour with intact membranes (n= 13) delivering at <34 weeks of gestation and 34 women with uncomplicated pregnancies (control group).

Methods  We compared plasma and vaginal PTX3 levels between study group and controls, and in women with versus women without clinical or histologic evidence of intrauterine infection using statistical analysis.

Main outcome measures  Peak PTX3 concentration.

Results  Peak PTX3 concentration in plasma samples of study group was significantly higher than that in controls (1175, 0–9630 versus 650, 0–1450 pg/ml; P= 0.0003) but not in vaginal swabs (1660, 0–6604 versus 457, 0–4649 pg/ml; P= 0.386). PTX3 levels in plasma were significantly higher in women with placenta vasculopathy compared with that in women with no placental lesions (2910, 0–9630 versus 636, 0–5692 pg/ml; P= 0.04). Peak plasma and vaginal PTX3 concentrations were not significantly different in women with versus women without intrauterine infection (1168, 0–7110 versus 845, 0–9630 pg/ml, P= 0.34 and 1975, 471–6604 versus 1919, 0–4150 pg/ml, P= 0.38, respectively).

Conclusions  Spontaneous PTD is associated with a significant increase of maternal plasma concentrations of PTX3. PTX3 seems to be a marker of placenta vasculopathy rather than intrauterine infection.