bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of Ba1−xSrxTiO3-based active thin films with silicon-compatible materials and process science protocols to enable affordable on-the-move communications technologies
Authors: Cole M. W. , Nothwang W. D. , Demaree J. D. , Hirsch S.
Published: July 2005

Integration of Ba1−xSrxTiO3- (BST) based thin films with affordable Si substrates has a potentially significant commercial impact as the demand for high-frequency tunable devices intensifies. Utilizing a coplanar device design we have monolithically integrated, optimized, and fabricated a high-performance composite bilayer heterostructure, Si∕Ta2O5∕BST, whereby the base layer film Ta2O5 serves as a passive buffer layer to allow integration of BST active thin films with affordable Si substrates. Optimization of this design configuration was achieved by evaluating two heterostructure processing protocols: (1) a single-anneal and (2) a dual-anneal process protocol. The reliability susceptibility, i.e., the nonabrupt defect-laden bilayer film interface, of the single-anneal protocol deemed it inappropriate for the fabrication of this monolithic heterostructure design. In contrast, the defect-free, structurally abrupt bilayer and buffer layer film-substrate interfaces suggest the dual anneal process to be an excellent method for realizing monolithic integration of BST with affordable Si substrates. This work suggests that the coefficient of thermal expansion mismatch between the Ta2O5 buffer and the BST thin films in the coplanar device design serves to enhance the dielectric tunability of the device. Realization of this materials integration technology serves to promote broadscale implementation of affordable tunable microwave devices across a variety of advanced communications platforms.
Excitation of the half-cyclotron waves by the counterstreaming electron-positron beams
Authors: Shokri B. , Khorashadizadeh S. M.
Published: July 2005

The dispersion relation of the half-cyclotron waves excited by the interaction of the two counterstreaming electron-positron-plasma beams is obtained. Furthermore, obtaining the growth rate and the threshold for the instability development, the excitation of the half-cyclotron waves in a system of two rotating monoenergetic electron-positron counterstreaming beams flowing parallel to the external magnetic field is investigated.
Magnetic force microscopy investigation of domain structures in Fe–xat.% Ga single crystals (12<x<25)
Authors: Bai Feiming , Li Jiefang , Viehland D. , Wu D. , Lograsso T. A.
Published: July 2005

The domain structure of furnace-cooled (FC) and post-annealed (PA) Fe–xat.% Ga (x=12, 20, and 25) crystals has been investigated by magnetic force microscopy. For both FC and PA Fe–12at.% Ga, the domains were found to be well-aligned and oriented along the [100] direction. For Fe–20at.% Ga, although a preferred [100] orientation remained, a difference in morphology was found between FC and PA conditions—in the PA condition, clear dendritic domains were observed. For both FC and PA Fe–25at.% Ga, a much reduced [100] preferred domain orientation was found, the domain size was notably reduced, and dendrite formation was not observed.
The semiclassical regime of the chaotic quantum-classical transition
Authors: Greenbaum Benjamin D. , Habib Salman , Shizume Kosuke , Sundaram Bala
Published: July 2005

An analysis of the semiclassical regime of the quantum-classical transition is given for open, bounded, one-dimensional chaotic dynamical systems. Environmental fluctuations—characteristic of all realistic dynamical systems—suppress the development of a fine structure in classical phase space and damp nonlocal contributions to the semiclassical Wigner function, which would otherwise invalidate the approximation. This dual regularization of the singular nature of the semiclassical limit is demonstrated by a numerical investigation of the chaotic Duffing oscillator.
Substrate-bias-dependent dielectric breakdown in ultrathin-oxide p-metal-oxide-semiconductor field-effect transistors
Authors: Chiang Sinclair , Lu M. F. , Huang-Lu S. , Chien S. C. , Wang Tahui
Published: July 2005

An explanation of the breakdown behavior of ultrathin-gate-oxide (1.6nm) p-metal-oxide-semiconductor field-effect transistors under a reverse substrate bias is presented. A significant degradation in lifetime induced by a positive substrate bias and a decrease in the power-law exponent (n) were observed. The quantitative hydrogen-based model [J. Sune and E. Wu, Digest of Technical Papers, 2001 Symposium on VLSI Technology, Kyoto, Japan, 12–14 June 2001 (unpublished), p. 97] is used to explain this observation while taking the channel quantization effect into consideration. Using this model, the stress voltage dependence of time-dependent dielectric breakdown in our experiment fits well with simulation results. This indicates that the degradation is due to the channel hole quantization-enhanced dissipation energy of injected electrons at the anode interface.
Molecular-beam epitaxial growth and characteristics of highly uniform InAs∕GaAs quantum dot layers
Authors: Mi Zetian , Bhattacharya Pallab
Published: July 2005

We have investigated the molecular-beam epitaxial growth and structural and photoluminescence characteristics of self-organized InAs∕GaAs quantum dot bilayers, in which a first seed layer of stressor dots is followed by a GaAs barrier layer and a second layer of active dots. At room temperature, the peak emission wavelength is at ∼1.4μm. By optimizing the growth parameters for both dot layers and the GaAs barrier layer, we have measured photoluminescence linewidths of 10.6 and 17.5meV at 20 and 300K, respectively. The measurement and analysis of temperature-dependent photoluminescence data indicate that there is no observable carrier redistribution amongst the dots with an increase of temperature and there is a high degree of size uniformity. The photoluminescence linewidth of 17.5meV at 300K is almost identical to that measured in the emission from a single dot, indicating that the linewidth is determined by homogeneous broadening.
Broadband absolute absorption measurements of atmospheric continua with millimeter wave cavity ringdown spectroscopy
Authors: Meshkov Andrey I. , De Lucia Frank C.
Published: July 2005

An instrument for the measurement of continua effects in the millimeter and submillimeter (a.k.a. terahertz) spectral region for mixtures of gases is described. In addition to their scientific interest, these continua are important because they contribute more than 50% of the opacity in the atmospheric windows important in remote sensing and communications. The instrument is based upon a fast scanning cavity ringdown approach that makes possible the measurement of continua and broad line absorptions at ∼6000 distinct cavity frequencies from 170to260GHz in ∼3s. The instrument’s 10m Fabry–Perot cavity (Q∼5×106) is in a chamber whose temperature can be controlled between −80 and +100°C and whose pressure can be varied between ∼10−5Torr and 10atm. The 3s scan results in statistical uncertainty in the absorptions of ∼2×10−7cm−1 at each of the 6000 frequencies. From these data an uncertainty of less than 1% for the weakest atmospheric continua (the dry air continuum) can be determined. For comparison, the continuum parameters that might be considered for inclusion in atmospheric remote sensing retrievals vary over a range of 10% to more than 50%. This uncertainty significantly impacts quality and validity of atmospheric retrievals from a variety of remote sensing platforms. While much lower statistical uncertainties are achievable with modest additional observation times, it is much more important that the near simultaneous measurements at many frequencies produce a data set that contains, without the use of parameters from other experiments, all of the required experimental information. This approach significantly reduces systematic effects and makes possible more realistic assessment of uncertainties.
Magnetic switching of ferromagnetic thin films under thermal perturbation
Authors: Liu Di , Garcia-Cervera Carlos
Published: July 2005

In this paper, we study the magnetic switching of submicron-sized ferromagnetic thin films under thermal noise and external field. It is shown that the presence of the noise makes the switching easier with weaker external fields and induces more intermediate metastable states in the switching pathways. Different switching pathways are preferred at different temperatures. A quantitative relation between the temperature and the switching field for different metastable states is given through an adjusted Arrhenius formula near the critical field. Based on this, preferred switching pathways at different temperatures are obtained by comparing the energy barriers along different pathways.
An interpretation of electrostatic density shocks in space plasma
Authors: Shi Jian-Kui , Zhang Tielong , Torkar Klaus , Liu Zhen-Xing
Published: July 2005

A physical model of electrostatic shocks observed in space plasma is established by deriving the “Sagdeev potential” from the magnetohydrodynamic equations in a cylindrical coordinate system. The results show that the electrostatic density shock and its corresponding solitary electric-field structure can develop from an ion acoustic wave or an ion cyclotron wave if the Mach number and the initial electric field satisfy some conditions. Some features of the shock wave are discussed. The result can be used to interpret the electrostatic shock observed in geospace plasma.
Dust-acoustic soliton in electronegative complex plasmas with streaming positive ions
Authors: Wang Zheng-Xiong , Wang Xiaogang , Ren Li-Wen , Liu Jin-Yuan , Liu Yue
Published: July 2005

The Sagdeev potential approach is applied to investigate theoretically and numerically the dust acoustic soliton in electronegative dusty plasmas with streaming positive ions. The self-consistent dust charge variation is also taken into account. The lower and upper limits of Mach numbers are then derived. Moreover, it is found that both the positive ion streaming velocity and negative ion density can lower the two limits. The soliton profiles, involving the spatial potential, particle densities, dust surface potential, and space net charge distributions in various cases, are plotted and discussed.
Electrical characteristics of SiOxFy gate oxides formed by a plasma fluorination technique
Authors: Kim D. S. , Lee Jino , Char K.
Published: July 2005

The electrical characteristics of metal-oxide-semiconductor capacitors with ultrathin fluorinated SiO2 formed by a plasma fluorination technique have been studied and correlated with the chemical properties. Our study showed that the fluorination of conventional SiO2 results in a reduction of leakage current and a small amount of fluorine doping can increase the oxide capacitance. From the analysis of electrical properties and x-ray photoelectron spectroscopy, the increase and decrease of capacitance for small and large amounts of F doping were attributed to filling up the dangling bonds with fluorine at the surface and the formation of fluorine-rich oxyfluoride in the bulk, respectively. The reduction of leakage current can be explained by the removal of hopping states or trap states originating from the Si dangling bonds and Si–H bonds and the resulting higher-energy barrier for the tunneling process.
Outer factorizations in one and several variables
Authors: Dritschel Michael , Woerdeman Hugo
Published: July 2005

A multivariate version of Rosenblum’s Fejér-Riesz theorem on outer factorization of trigonometric polynomials with operator coefficients is considered. Due to a simplification of the proof of the single variable case, new necessary and sufficient conditions for the multivariable outer factorization problem are formulated and proved.
HTHquery: a method for detecting DNA-binding proteins with a helix-turn-helix structural motif
Authors: Ferrer-Costa C. , Shanahan H. P. , Jones S. , Thornton J. M.
Published: July 2005

Summary: HTHquery is a web-based service to determine if a protein structure has a helix-turn-helix structural motif which could bind to DNA. It is based on a similarity with a set of structural templates, the accessibility of a putative structural motif and a positive electrostatic potential in the neighbourhood of the putative motif. A set of scores are computed, based on each template, using a linear predictor. From the training set used, the predictor has a true positive rate of 83.5% and a false positive rate of 0.8%. The emphasis for the website is on providing a straightforward interface which can be easily used by a bench-based scientist.

Availability: HTHquery is implemented using a set of Perl scripts and C program and can be accessed freely on the website http://www.ebi.ac.uk/thornton-srv/databases/HTHquery

Contact:  Hugh.Shanahan@physics.org
GeneCruiser: a web service for the annotation of microarray data
Authors: Liefeld Ted , Reich Michael , Gould Joshua , Zhang Peili , Tamayo Pablo , Mesirov Jill P.
Published: July 2005

Summary: GeneCruiser is a web service allowing users to annotate their genomic data by mapping microarray feature identifiers to gene identifiers from databases, such as UniGene, while providing links to web resources, such as the UCSC Genome Browser. It relies on a regularly updated database that retrieves and indexes the mappings between microarray probes and genomic databases. Genes are identified using the Life Sciences Identifier standard.

Availability: GeneCruiser is freely available in the following forms: Web service and Web application, http://www.genecruiser.org; GenePattern, GeneCruiser access has been integrated into our microarray analysis platform, GenePattern. http://www.genepattern.org

Contact:  liefeld@broad.mit.edu
Phylogeny of African complete genomes reveals a West African genotype A subtype of hepatitis B virus and relatedness between Somali and Asian A1 sequences
Authors: Hannoun Charles , Söderström Ann , Norkrans Gunnar , Lindh Magnus
Published: July 2005

Hepatitis B virus (HBV) is a major cause worldwide of liver disease, including hepatocellular carcinoma. There are eight known genotypes (A–H), of which genotype A has been divided into two subtypes: A2, prevalent in Europe, and A1, which is prevalent in sub-Saharan Africa, but also occurs in southern Asia. In this study, which includes 14 new complete genomes of non-European genotype A HBV, it was found that West African strains seem to constitute a new subgroup, A3. The high degree of genetic diversity within Africa indicates that genotype A originates from Africa. Based on a 2 % genetic distance between Asian and Somali sequences, it seems that the A1 subtype has spread from East Africa to southern Asia during the last 1000–2000 years. Moreover, it is proposed here that the A2 subtype originates from southern Africa and was imported to Europe around 500 years ago or later. The finding of T-1809/1812 close to the precore start codon and T-1862 and A-1888 in the precore region in HBV e antigen-positive children with signs of a mimimal immune response indicates that these substitutions are stable variants, rather than mutations emerging during infection in individual carriers.
Elimination of transmissible spongiform encephalopathy infectivity and decontamination of surgical instruments by using radio-frequency gas-plasma treatment
Authors: Baxter H. C. , Campbell G. A. , Whittaker A. G. , Jones A. C. , Aitken A. , Simpson A. H. , Casey M. , Bountiff L. , Gibbard L. , Baxter R. L.
Published: July 2005

It has now been established that transmissible spongiform encephalopathy (TSE) infectivity, which is highly resistant to conventional methods of deactivation, can be transmitted iatrogenically by contaminated stainless steel. It is important that new methods are evaluated for effective removal of protein residues from surgical instruments. Here, radio-frequency (RF) gas-plasma treatment was investigated as a method of removing both the protein debris and TSE infectivity. Stainless-steel spheres contaminated with the 263K strain of scrapie and a variety of used surgical instruments, which had been cleaned by a hospital sterile-services department, were examined both before and after treatment by RF gas plasma, using scanning electron microscopy and energy-dispersive X-ray spectroscopic analysis. Transmission of scrapie from the contaminated spheres was examined in hamsters by the peripheral route of infection. RF gas-plasma treatment effectively removed residual organic residues on reprocessed surgical instruments and gross contamination both from orthopaedic blades and from the experimentally contaminated spheres.In vivotesting showed that RF gas-plasma treatment of scrapie-infected spheres eliminated transmission of infectivity. The infectivity of the TSE agent adsorbed on metal spheres could be removed effectively by gas-plasma cleaning with argon/oxygen mixtures. This treatment can effectively remove ‘stubborn’ residual contamination on surgical instruments.
A novel homologue of Human herpesvirus 6 in chimpanzees
Authors: Lacoste Vincent , Verschoor Ernst J. , Nerrienet Eric , Gessain Antoine
Published: July 2005

Among the Betaherpesvirinae, human cytomegalovirus is the only virus to possess simian homologues. Indeed, intriguingly, no close simian homologue of the roseoloviruses Human herpesvirus 6 (HHV-6) and Human herpesvirus 7 (HHV-7), the other two human members of the Betaherpesvirinae, has been identified to date. Here, the first simian homologue of HHV-6 is described, which was identified in common chimpanzees and designated PanHV6. By using a degenerate consensus PCR method, three different gene fragments were amplified, corresponding to the DNA polymerase (U38), β-chemokine receptor (U12) and viral transactivator (U42) genes, with 94–96 % (nucleotide) and 95–97 % (amino acid) sequence identity to the corresponding genes of HHV-6B. Analysis of 77 predominantly wild-caught chimpanzees identified a unique PanHV6 strain in 21 animals, with no viral sequence variation between the different chimpanzee subspecies that were found to be infected. Characterization of this virus represents a great potential to gain a better understanding of the diseases associated with HHV-6.
Ovarian dynamics in relation to host quality in the Walnut‐infesting Fly, Rhagoletis juglandis
Authors: PAPAJ D. R.
Published: July 2005

Reproductive behaviour is routinely studied with a view towards characterizing how an animal responds to variation in resource abundance and quality. This characterization is less commonly made with respect to reproductive physiology.

In the Walnut‐infesting Fly, Rhagoletis juglandis, ovarian development is cued by the presence of the host fruit resource. In this study, I examined how ovarian development was affected by two host characteristics that relate to competition in the juvenile stages: fruit size and presence of conspecific larvae.

Large fruit promoted egg maturation more than small fruit, and uninfested fruit promoted maturation more than larval‐infested fruit. Both effects were reproduced with artificial models of fruit.

The functional significance of these effects and ramifications for individual‐level dynamics in oviposition behaviour are discussed.
Female‐biased mortality in experimentally parasitized Alpine SwiftApus melbanestlings
Authors: BIZE P. , ROULIN A. , TELLA J. L. , RICHNER H.
Published: July 2005

Sex‐biased mortality in adult vertebrates is often attributed to lower immunocompetence and higher parasite susceptibility of males. Although sex‐specific mortality has also been reported during growth, the importance of sex‐specific immunocompetence and parasite susceptibility in explaining male‐biased mortality remains ambiguous in growing individuals because of potentially confounding sources of mortality such as sexual dimorphism.

Here, we investigated sex‐specific susceptibility to the blood‐sucking louse flyCrataerina melbaeand sex differences in cell‐mediated immunity in a bird species that is sexually monomorphic both in size and plumage coloration at the nestling stage, the Alpine Swift,Apus melba.

For this purpose, we manipulated ectoparasite loads by adding or removing flies to randomly chosen nests in two years, and injected nestlings with mitogenic phytohaemagglutinin (PHA) in another year.

There were no significant differences between male and female offspring in immune response towards PHA, parasite load, and parasite‐induced decrease in growth rate. Secondary sex ratios were however biased toward males in parasitized broods, and this was explained by a greater mortality of females in parasitized than deparasitized broods.

Our findings are in contrast to the widely accepted hypothesis that males suffer a greater cost of parasitism. We discuss alternative hypotheses accounting for female‐specific mortality.
Ex vitro composite plants: an inexpensive, rapid method for root biology
Authors: Collier Ray , Fuchs Beth , Walter Nathalie , Kevin Lutke William , Taylor Christopher G.
Published: July 2005

Plant transformation technology is frequently the rate‐limiting step in gene function analysis in non‐model plants. An important tool for root biologists is the Agrobacterium rhizogenes‐derived composite plant, which has made possible genetic analyses in a wide variety of transformation recalcitrant dicotyledonous plants. The novel, rapid and inexpensive ex vitro method for producing composite plants described in this report represents a significant advance over existing composite plant induction protocols, which rely on expensive and time‐consuming in vitro conditions. The utility of the new system is validated by expression and RNAi silencing of GFP in transgenic roots of composite plants, and is bolstered further by experimental disruption, via RNAi silencing, of endogenous plant resistance to the plant parasitic nematode Meloidogyne incognita in transgenic roots of Lycopersicon esculentum cv. Motelle composite plants. Critical parameters of the method are described and discussed herein.
Molecular tailoring of farnesylation for plant drought tolerance and yield protection
Authors: Wang Yang , Ying Jifeng , Kuzma Monika , Chalifoux Maryse , Sample Angela , McArthur Charlene , Uchacz Tina , Sarvas Carlene , Wan Jiangxin , Dennis David T. , McCourt Peter , Huang Yafan
Published: July 2005

Protecting crop yield under drought stress is a major challenge for modern agriculture. One biotechnological target for improving plant drought tolerance is the genetic manipulation of the stress response to the hormone abscisic acid (ABA). Previous genetic studies have implicated the involvement of the β‐subunit of Arabidopsis farnesyltransferase (ERA1) in the regulation of ABA sensing and drought tolerance. Here we show that molecular manipulation of protein farnesylation in Arabidopsis, through downregulation of either the α‐ or β‐subunit of farnesyltransferase enhances the plant's response to ABA and drought tolerance. To test the effectiveness of tailoring farnesylation in a crop plant, transgenic Brassica napus carrying an ERA1 antisense construct driven by a drought‐inducible rd29A promoter was examined. In comparison with the non‐transgenic control, transgenic canola showed enhanced ABA sensitivity, as well as significant reduction in stomatal conductance and water transpiration under drought stress conditions. The antisense downregulation of canola farnesyltransferase for drought tolerance is a conditional and reversible process, which depends on the amount of available water in the soil. Furthermore, transgenic plants were more resistant to water deficit‐induced seed abortion during flowering. Results from three consecutive years of field trial studies suggest that with adequate water, transgenic canola plants produced the same amount of seed as the parental control. However, under moderate drought stress conditions at flowering, the seed yields of transgenic canola were significantly higher than the control. Using protein farnesyltransferase as an effective target, these results represent a successful demonstration of engineered drought tolerance and yield protection in a crop plant under laboratory and field conditions.
Arabidopsis CUL3A and CUL3B genes are essential for normal embryogenesis
Authors: Thomann Alexis , Brukhin Vladimir , Dieterle Monika , Gheyeselinck Jacqueline , Vantard Marylin , Grossniklaus Ueli , Genschik Pascal
Published: July 2005

Cullin (CUL)‐dependent ubiquitin ligases form a class of structurally related multisubunit enzymes that control the rapid and selective degradation of important regulatory proteins involved in cell cycle progression and development, among others. The CUL3‐BTB ligases belong to this class of enzymes and despite recent findings on their molecular composition, our knowledge on their functions and substrates remains still very limited. In contrast to budding and fission yeast, CUL3 is an essential gene in metazoans. The model plant Arabidopsis thaliana encodes two related CUL3 genes, called CUL3A and CUL3B. We recently reported that cul3a loss‐of‐function mutants are viable but exhibit a mild flowering and light sensitivity phenotype. We investigated the spatial and temporal expression of the two CUL3 genes in reproductive tissues and found that their expression patterns are largely overlapping suggesting possible functional redundancy. Thus, we investigated the consequences on plant development of combined Arabidopsis cul3a cul3b loss‐of‐function mutations. Homozygous cul3b mutant plants developed normally and were fully fertile. However, the disruption of both the CUL3A and CUL3B genes reduced gametophytic transmission and caused embryo lethality. The observed embryo abortion was found to be under maternal control. Arrest of embryogenesis occurred at multiple stages of embryo development, but predominantly at the heart stage. At the cytological level, CUL3 loss‐of‐function mutations affected both embryo pattern formation and endosperm development.
Unilateral macular oedema secondary to retinal venous congestion without occlusion in patients with diabetes mellitus
Authors: Larsen Michael
Published: July 2005

Objective:  To identify fundus characteristics associated with intraocular and intra‐individual variations in the distribution of macular oedema in patients with diabetes.

Methods:  A review was carried out of fundus photographs and fluorescein angiograms from 226 diabetes patients who received photocoagulation treatment for macular oedema. Cases with strictly unilateral clinically significant macular oedema were identified.

Results:  Strictly unilateral macular oedema was identified in five patients with non‐proliferative diabetic retinopathy, three of whom demonstrated angiographic leakage confined to a single venous drainage unit, and two of whom demonstrated leakage confined to two adjacent venous drainage units opposing one another on either side of the temporal circulatory watershed. Involved drainage units were delimited by arteriovenous crossings displaying signs of venous compression. Affected eyes had more frequent and more severe crossing signs involving macular drainage than fellow eyes. Although all patients had been examined regularly, no patient had had branch retinal vein occlusion and no patient developed such occlusion during 5 years of follow‐up.

Conclusion:  In the present study, unilateral macular oedema in patients with diabetes was associated with angiographic leakage from venous drainage units where compression signs indicated a higher than normal likelihood of upstream congestion being present. Presumably, a modest increase in venous pressure induced macular oedema because of an underlying abnormal vascular vulnerability induced by diabetes.
Scaling the structure−function relationship for clinical perimetry
Authors: Harwerth Ronald S. , Carter‐Dawson Louvenia , Smith Earl L. , Crawford Morris L. J.
Published: July 2005

Purpose:  The full ranges of glaucomatous visual field defects and retinal ganglion cell losses extend over several orders of magnitude and therefore an interpretation of the structure−function relationship for clinical perimetry requires scaling of both variables. However, the most appropriate scale has not been determined. The present study was undertaken to compare linear and logarithmic transformations, which have been proposed for correlating the perimetric defects and neural losses of glaucoma.

Methods:  Perimetry, by behavioural testing, and retinal histology data were obtained from rhesus monkeys with significant visual field defects caused by experimental glaucoma. Ganglion cell densities were measured in histologic sections of retina that corresponded to specific perimetry test locations for the treated and control eyes. The linear (percentage) and logarithmic (decibel) relationships for sensitivity loss as a function of ganglion cell loss were analysed.

Results:  With decibel scaling, visual sensitivity losses and ganglion cell densities were linearly correlated with high coefficients of determination (r2), although the parameters of the functions varied with eccentricity. The structure−function relationships expressed as linear percentage‐loss functions were less systematic in two respects. Firstly, the relationship exhibited considerable scatter in the data for small losses in visual sensitivity and, secondly, visual sensitivity losses became saturated with larger losses in ganglion cell density. The parameters of the percentage‐loss functions also varied with eccentricity, but the variation was less than for the decibel‐loss functions.

Conclusions:  Linear scaling of perimetric defects and ganglion cell losses might potentially improve the structure−function relationship for visual defects associated with small amounts of cell loss, but the usefulness of the relationship is limited because of the high variability in that range. With log−log co‐ordinates, the structure−function relationship for clinical perimetry is relatively more accurate and precise for cell losses greater than about 3 dB. The comparatively greater accuracy and precision of decibel loss functions are a likely consequence of the logarithmic scale of stimulus intensities for perimetry measurements and because the relationship between visual sensitivity and the number of neural detectors is a form of probability summation.
Colour contrast sensitivity with different intraocular lens materials in the right and left eyes in same day surgery
Authors: Friström Björn , Lundh Björn L.
Published: July 2005

Purpose:  To study possible differences in colour contrast sensitivity between different intraocular lens (IOL) materials with consecutive same day cataract surgery performed in the right and left eyes.

Methods:  Central colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes. Thirty‐four patients with cataract were studied. The patients were randomized to one of three groups: group 1 received a Clariflex (silicone) lens in one eye and an Akreos Fit (hydrophilic acrylic) lens in the other; group 2 received an Akreos lens in one eye and a Sensar AR40e (hydrophobic acrylic) lens in the other, and group 3 received a Clariflex lens in one eye and an AR40e lens in the other. Surgery was performed in both eyes on the same day. A postoperative questionnaire was distributed, asking the patients to describe any differences experienced between their two eyes.

Results:  There were no significant differences between the three different IOLs in any colour axis. There were no complications of importance during surgery. Thirty‐two of the 34 patients answered the questionnaire. Twenty‐one patients experienced some difference between their two eyes in distance vision and 23 noticed differences in near vision. For distance vision, nine reported better vision in the eye with the Akreos IOL, eight in the eye with the Clariflex IOL lens and four in the eye with the AR40e IOL. For near vision, 12 preferred the Akreos lens, eight the Clariflex lens and three the AR40e lens.

Conclusion:  There were no significant differences between the three different IOLs in any colour axis.
Surveys for asymptomatic persistence of Sphaeropsis sapinea on or in stems of red pine seedlings from seven Great Lakes region nurseries
Authors: Stanosz G. R. , Smith D. R. , Albers J. S.
Published: July 2005

The fungus Sphaeropsis sapinea persists on or in stems of asymptomatic red pine (Pinus resinosa) nursery seedlings, and proliferates to cause collar rot and mortality after planting. In the spring of 2002, seven nurseries were surveyed to determine the potential range in frequency of asymptomatic persistence: three operated by Wisconsin Department of Natural Resources (DNR), two by Minnesota DNR, one by Michigan DNR, and one by USDA Forest Service (in Michigan). At each nursery five groups of 20 asymptomatic red pine seedlings were collected near an inoculum source (red pine windbreak), if present, and five groups of 20 asymptomatic seedlings were collected away from such a source (1400 seedlings total). A segment of the lower stem/root collar from each seedling was surface disinfested and incubated on tannic acid agar. Transfers were made from resulting colonies and the pathogen identified from pycnidia and conidia produced in culture. The pathogen was identified from asymptomatic seedlings collected in all Wisconsin and Minnesota nurseries, but was never detected from seedlings from the Michigan DNR or USDA Forest Service nurseries. Frequencies of detection were greater (as high as 88%) from asymptomatic seedlings near red pine windbreaks including diseased trees than from seedlings distant from such windbreaks. A subset of isolates from asymptomatic seedlings was characterized using inter‐simple sequence repeat–polymerase chain reaction analysis. Most isolates were the A group of S. sapinea, but B group isolates (recently named Diplodia scrobiculata) were also obtained from one nursery. One Minnesota nursery was more extensively sampled in 2003, with 17–44 groups of five asymptomatic red pine seedlings collected in four separate fields (525 seedlings total). The mean frequency of detection of the pathogen in these four fields ranged from 40 to 71%. Persistence of S. sapinea on or in asymptomatic seedlings continues to be problematic, not only because of the potential for subsequent seedling mortality, but also as a means by which a pathogen may be widely distributed.
Differentiating the two closely related species, Phellinus weirii and P. sulphurascens
Authors: Lim Y. W. , Yeung Y. C. A. , Sturrock R. , Leal I. , Breuil C.
Published: July 2005

Phellinus weirii s.l., an aggressive root rot pathogen, causes extensive wood losses and lowers the productivity of western red cedar (WRC, Thuja plicata), Douglas fir (Pseudotsuga menziesii) and other conifers. This fungus has been recognized as a cedar form (P. weirii s.s.) and a non‐cedar form (P. sulphurascens). Differentiating the two species is difficult because their fruiting bodies and cultural morphologies are very similar. However, differences in growth rate and colony morphology were observed when they were grown on malt extract agar with WRC feeder strips. In addition, different restriction fragment length polymorphism patterns were obtained using (i) the internal transcribed spacer (ITS) region cut with the restriction enzyme RsaI, and (ii) the partial large subunit ribosomal DNA region cut with AgeI and NciI. Furthermore, a new specific primer set was designed from the ITS region of P. weirii s.s. and was used to differentiate it from P. sulphurascens and other decay fungi that are frequently found in coniferous trees. These species‐specific primers will facilitate the detection of P. weirii in standing trees well before visible signs of infection are apparent.
Multi‐seasonal field release and spermatization trials of transgenic hypovirulent strains of Cryphonectria parasitica containing cDNA copies of hypovirus CHV1‐EP713
Authors: Root C. , Balbalian C. , Bierman R. , Geletka L. M. , Anagnostakis S. , Double M. , MacDonald W. , Nuss D. L.
Published: July 2005

Three indigenous field strains of the chestnut blight fungus, Cryphonectria parasitica collected in 1996 from a test site in the Meshomasic State Forest, Connecticut, USA, were engineered to contain a chromosomally integrated full‐length infectious cDNA copy of the severe, virulence‐attenuating hypovirus CHV1‐EP713. These transgenic hypovirulent strains were introduced into the test site after it had been clear‐cut, as sprayed conidia in multiple applications over 4 years, beginning in 1997. Evidence was obtained for cytoplasmic transmission of cDNA‐derived hypovirus RNA and for recovery of transgenic strains from canker tissue of the spray‐treated trees. However, there was no indication of spread of transgenic strains or cDNA‐derived viral RNA to the control plot or outside the treatment plot. A single transgenic C. parasitica isolate was identified from a total of 156 isolates recovered from 1330 insects representing five insect orders. Only 2.6% of the 1082 C. parasitica bark isolates recovered during the course of this study were vegetatively compatible with the untransformed input strains. Transgenic ascospore progeny were produced by 40% of the perithecia collected in 1999 and by only 7.3% of the perithecia collected in 2000. A concurrent field release study performed in the Monongahela National Forest in West Virginia in 1998 and 1999 with transgenic hypovirulent strains constructed with the same CHV1‐EP713 cDNA‐containing plasmid identified seasonal application dates and delivery methods that resulted in very high levels of transgenic ascospore production. Results of the combined field release studies are discussed in terms of requirements for improved formulations and delivery methods and the importance of balancing ecological fitness and virulence attenuation.
Visual loss due to central serous chorioretinopathy during corticosteroid treatment for giant cell arteritis
Authors: Bevis Timothy , Ratnakaram Ramakrishna , Smith M Fran , Bhatti M Tariq
Published: July 2005

Abstract

Giant cell arteritis (GCA) can be a devastating disease resulting in blindness if not promptly diagnosed and treated. The only proven treatment for GCA is systemic corticosteroids; however, there are many side‐effects associated with this therapy including ocular side‐effects such as ocular hypertension, cataract formation and central serous chorioretinopathy. To raise physician awareness, a patient with biopsy‐proven GCA is reported who lost vision during corticosteroid therapy because of central serous chorioretinopathy.
Survey of eye practitioners’ attitudes towards diagnostic tests and therapies for dry eye disease
Authors: Turner Angus W , Layton Christopher J , Bron Anthony J
Published: July 2005

Abstract

Background:  There is a wide variation in the use of diagnostic tests for dry eye disease. The purpose of this study was to survey the attitudes of eye practitioners towards both tests and therapies available for dry eye disease.

Method:  An anonymous, web‐based questionnaire was used, containing both quantitative and qualitative sections. 

Results:  Thirty‐eight respondents, evenly distributed in experience, confirmed the wide variation of diagnostic tests in use. History and staining techniques were significantly preferred to tests of tear flow (P < 0.05). ‘Evidence’ was the most valued test characteristic, and was regarded as significantly more important than ‘comfort’ or ‘cost’ (P < 0.003). However, ‘evidence’ was not valued significantly higher than ‘ease of use’ or ‘time taken to perform’. Overall, there was poor satisfaction with diagnostic and therapeutic options in dry eye, for both quantitative and qualitative measures.

Conclusion:  This is the first qualitative study of attitudes towards dry eye disease. Attitudes towards the adequacy of diagnostic tests vary considerably. As evidence supporting a diagnostic test's validity is the most highly valued test characteristic, a systematic review of the topic is justified.
Centripetal lens epithelial cell migration: a prospective study of the Alcon SA60AT intraocular lens
Authors: Assaad Nagi N , Cheung Leanne M , Lim Charmaine , Francis Ian C , Coroneo Minas T , Alexander Stella L , Schumacher R Steve
Published: July 2005

Abstract

Purpose:  To evaluate prospectively the incidence and severity of centripetal lens epithelial cell migration (CLECM) onto the anterior surface of the Alcon SA60AT intraocular lens (IOL).

Methods:  One hundred and four consecutive cases of SA60AT IOL implantations were prospectively evaluated. At the 1‐month postoperative visit, best corrected visual acuity (BCVA) was obtained. Following maximal pupillary dilatation, the extent of CLECM was assessed using a simplified grading scale (0–4). The centrality of the lens within the capsular bag was recorded. Patients with the highest grade of CLECM were recalled for reassessment at a minimum of 3 months.

Results:  Centripetal lens epithelial cell migration data were obtained on 99 patients. Of these, 94% demonstrated CLECM  of  varying  severity  at  1 month  postoperatively.  The severity was low grade in 54% of patients (29% grade 1, 24% grade 2), and high grade in 40% of patients (16% grade 3, 24% grade 4). BCVA results were good (91.9% 6/6 or better) and did not correlate with CLECM grade. Operative capsulorhexis size did not correlate with the severity of CLECM. The lens was well‐centred in 91 of 92 patients in whom lens position was assessed. Twenty‐three patients with grade 4 CLECM at 1 month were brought back for reassessment (3.5–13 months postoperatively) and 18 of these demonstrated complete regression of CLECM (to grade 0).

Conclusions:  There is a high incidence and severity of CLECM 1 month postoperatively using the Alcon SA60AT IOL. There was no significant correlation between CLECM grade and either BCVA at 1 month, capsulorhexis size or lens centration. CLECM appears to be a frequent, benign and transient event with this lens.
Bioavailability of vitamin B12 using a small‐volume nebulizer ophthalmic drug delivery system
Authors: Kahn Monte
Published: July 2005

Abstract

Background:  To determine the intraocular bioavailability of a novel embodiment for vitamin B12 delivered to the ocular surface by a piezo‐electric ultrasonic nebulizer.

Methods:  The semisolid embodiment contained 0.02% (w/w) vitamin B12 in 1 g of ointment, which was immiscible and insoluble in 5 mL sterilized warm water. To confirm in vitro functionality, nebulized mist particles of the embodiment were collected and analysed for vitamin B12 content. The in vivo arm of the study was designed as randomization of 23 patients who were scheduled to undergo cataract surgery in hospital. Fourteen patients were treated with nebulized vitamin B12, five patients had one drop of 0.02% vitamin B12 instilled in the conjunctival cul de sac, and four control patients had no medication. Twelve hours after the vitamin was delivered, the patients underwent the cataract procedure and a sample of aqueous humour was collected from each. High performance liquid chromatography was used for detection of vitamin B12 in all samples.

Results:  The in vitro analysis of mist particles showed increasing concentrations of vitamin B12. In the patient tests, analysis of the aqueous humour samples showed that none of the controls or those receiving eye drops had detectable vitamin B12 in the aqueous humour. However, 4 of 14 in the nebulizer group had vitamin B12 detected in the aqueous humour in the amount of 10−7 mol.

Conclusions:  The small‐volume nebulizer system might provide another method of ophthalmic drug delivery.
A tribute to Dr Medduma B Kappagoda
Authors: Francis Ian C
Published: July 2005

Abstract

Dr Medduma B Kappagoda (‘Kappa’) was a dynamic, unique ophthalmologist. His knowledge and comprehension of ophthalmology were outstanding. He is best remembered for his love of and care for people of all backgrounds, his teaching and his sense of humour.
Cavernous haemangioma in the orbital apex: stereotactic‐guided transcranial cryoextraction
Authors: Papalkar Daya , Francis Ian C , Stoodley Marcus , Kaines Andrew , Sharma Shanel , Kalapesi Freny B , Wilcsek Geoffrey A
Published: July 2005

Abstract

A 55‐year‐old Caucasian woman presented with an orbital cavernous haemangioma superior to the optic nerve in the orbital apex. Preoperative imaging demonstrated a mass involving the superomedial and superolateral quadrants of the posterior orbit. A stereotactic fronto‐orbital approach was performed by the neurosurgical team, and cryoextraction of the lesion was accomplished by the ocular plastic surgical team.
Anterior chamber‐associated immune deviation: a review of the anatomical evidence for the afferent arm of this unusual experimental model of ocular immune responses
Authors: Camelo Serge , Kezic Jelena , McMenamin Paul G
Published: July 2005

Abstract

Anterior chamber‐associated immune deviation (ACAID) is an animal model of tolerance induced experimentally by the injection of antigen into the anterior chamber of the eye. The unusual deviant immune response has both afferent and efferent arms and it is the former that is the focus of this review. The paradigm states that antigen injected into the anterior chamber of the eye is internalized by intraocular antigen presenting cells (APCs) which then migrate largely to the spleen to induce the differentiation of regulatory T cell populations which in turn form the basis of the modified efferent arm to the deviant immune response. However, the migration routes of ocular APCs or free antigen to the secondary lymphoid organs remain unclear. In this review we will discuss the evidence for different possible afferent routes by which antigen (either free or cell‐associated) leaves the eye and the pattern of distribution to secondary lymphoid organs.
Use of intravitreal triamcinolone in the management of birdshot retinochoroidopathy associated with cystoid macular oedema: a case study over a three‐year period
Authors: Shah Anup , Branley Michael
Published: July 2005

Abstract

Birdshot retinochoroidopathy is a bilateral, chronic posterior uveitis of likely autoimmune aetiology characterized by multiple depigmented choroidal lesions scattered throughout the post‐equatorial retina. It has been managed with variable results using systemic immunosuppression. Herein, a case is described in which the patient, aware of the side‐effects of systemic immunosuppression, refused this form of treatment and was successfully managed over a 3‐year period with intravitreal triamcinolone. She developed the ocular complications of cataract and increased intraocular pressures, but maintained good vision while avoiding any systemic side‐effects.
Balance of pro‐apoptotic transforming growth factor‐β and anti‐apoptotic insulin effects in the control of cell death in the postnatal mouse retina
Authors: Duenker N. , Valenciano A. I. , Franke A. , Hernández‐Sánchez C. , Dressel R. , Behrendt M. , De Pablo F. , Krieglstein K. , De La Rosa E. J.
Published: July 2005

Transforming growth factor (TGF)‐β and insulin display opposite effects in regulating programmed cell death during vertebrate retina development; the former induces apoptosis while the latter prevents it. In the present study we investigated coordinated actions of TGF‐β and insulin in an organotypic culture system of early postnatal mouse retina. Addition of exogenous TGF‐β resulted in a significant increase in cell death whereas exogenous insulin attenuated apoptosis and was capable of blocking TGF‐β‐induced apoptosis. This effect appeared to be modulated via insulin‐induced transcriptional down‐regulation of TGF‐β receptor II levels. The analysis of downstream signalling molecules also revealed opposite effects of both factors; insulin provided survival signalling by increasing the level of anti‐apoptotic Bcl‐2 protein expression and phosphorylation and down‐regulating caspase 3 activity whereas pro‐apoptotic TGF‐β signalling reduced Bcl‐2 mRNA levels and Bcl‐2 phosphorylation and induced the expression of TGF‐induced immediate‐early gene (TIEG), a Krüppel‐like zinc‐finger transcription factor, mimicking TGF‐β activity.