bluuebunny/crossref_metadata_2025 huggingface dataset:
The mitochondrial uncoupler 2,4‐dinitrophenol attenuates tissue damage and improves mitochondrial homeostasis following transient focal cerebral ischemia
Authors: Korde Amit S. , Pettigrew L. Creed , Craddock Susan D. , Maragos William F.
Published: August 2005

Ischemic stroke is caused by acute neuronal degeneration provoked by interruption of cerebral blood flow. Although the mechanisms contributing to ischemic neuronal degeneration are myriad, mitochondrial dysfunction is now recognized as a pivotal event that can lead to either necrotic or apoptotic neuronal death. Lack of suitable ‘upstream’ targets to prevent loss of mitochondrial homeostasis has, so far, restricted the development of mechanistically based interventions to promote neuronal survival. Here, we show that the uncoupling agent 2,4 dinitrophenol (DNP) reduces infarct volume approximately 40% in a model of focal ischemia–reperfusion injury in the rat brain. The mechanism of protection involves an early decrease in mitochondrial reactive oxygen species formation and calcium uptake leading to improved mitochondrial function and a reduction in the release of cytochrome c into the cytoplasm. The observed effects of DNP were not associated with enhanced cerebral perfusion. These findings indicate that compounds with uncoupling properties may confer neuroprotection through a mechanism involving stabilization of mitochondrial function.
Apoptosis inducing factor mediates caspase‐independent 1‐methyl‐4‐phenylpyridinium toxicity in dopaminergic cells
Authors: Chu Charleen T. , Zhu Jian‐hui , Cao Guodong , Signore Armando , Wang Suping , Chen Jun
Published: August 2005

Parkinson's disease is a debilitating neurodegenerative disease characterized by loss of midbrain dopaminergic neurons. These neurons are particularly sensitive to the neurotoxin 1‐methyl‐4‐phenylpyridinium (MPP+), the active metabolite of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), which causes parkinsonian syndromes in humans, monkeys and rodents. Although apoptotic cell death has been implicated in MPTP/MPP+ toxicity, several recent studies have challenged the role of caspase‐dependent apoptosis in dopaminergic neurons. Using the midbrain‐derived MN9D dopaminergic cell line, we found that MPP+ treatment resulted in an active form of cell death that could not be prevented by caspase inhibitors or over‐expression of a dominant negative inhibitor of apoptotic protease activating factor 1/caspase‐9. Apoptosis inducing factor (AIF) is a mitochondrial protein that may mediate caspase‐independent forms of regulated cell death following its translocation to the nucleus. We found that MPP+ treatment elicited nuclear translocation of AIF accompanied by large‐scale DNA fragmentation. To establish the role of AIF in MPP+ toxicity, we constructed a DNA vector encoding a short hairpin sequence targeted against AIF. Reduction of AIF expression by RNA interference inhibited large‐scale DNA fragmentation and conferred significant protection against MPP+ toxicity. Studies of primary mouse midbrain cultures further supported a role for AIF in caspase‐independent cell death in MPP+‐treated dopaminergic neurons.
Enhanced caffeine‐induced Ca2+release in the 3xTg‐AD mouse model of Alzheimer's disease
Authors: Smith Ian F. , Hitt Brian , Green Kim N. , Oddo Salvatore , LaFerla Frank M.
Published: August 2005

Alzheimer's disease (AD) is the most prevalent form of dementia among the elderly and is a complex disorder that involves altered proteolysis, oxidative stress and disruption of ion homeostasis. Animal models have proven useful in studying the impact of mutant AD‐related genes on other cellular signaling pathways, such as Ca2+signaling. Along these lines, disturbances of intracellular Ca2+([Ca2+]i) homeostasis are an early event in the pathogenesis of AD. Here, we have employed microfluorimetric measurements of [Ca2+]ito investigate disturbances in Ca2+homeostasis in primary cortical neurons from a triple transgenic mouse model of Alzheimer's disease (3xTg‐AD). Application of caffeine to mutant presenilin‐1 knock‐in neurons (PS1KI) and 3xTg‐AD neurons evoked a peak rise of [Ca2+]ithat was significantly greater than those observed in non‐transgenic neurons, although all groups had similar decay rates of their Ca2+transient. This finding suggests that Ca2+stores are greater in both PS1KIand 3xTg‐AD neurons as calculated by the integral of the caffeine‐induced Ca2+transient signal. Western blot analysis failed to identify changes in the levels of several Ca2+binding proteins (SERCA‐2B, calbindin, calsenilin and calreticulin) implicated in the pathogenesis of AD. However, ryanodine receptor expression in both PS1KIand 3xTg‐AD cortex was significantly increased. Our results suggest that the enhanced Ca2+response to caffeine observed in both PS1KIand 3xTg‐AD neurons may not be attributable to an alteration of endoplasmic reticulum store size, but to the increased steady‐state levels of the ryanodine receptor.
Phosphorylation‐dependent interactions of α‐Actinin‐1/IQGAP1 with the AMPA receptor subunit GluR4
Authors: Nuriya Mutsuo , Oh Sekyung , Huganir Richard L.
Published: August 2005

AMPA (α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid) receptors play key roles in excitatory synaptic transmission and synaptic plasticity in the CNS. Although a variety of proteins has been characterized to interact with AMPA receptors and regulate their function, little is known about the regulation of the AMPA receptor subunit GluR4. To understand the molecular mechanisms of GluR4 functional regulation, the yeast two‐hybrid system was used to identify GluR4‐interacting molecules. α‐Actinin‐1 and IQGAP1 were identified to be GluR4‐specific binding partners. Both proteins interact specifically with GluR4 and co‐cluster with GluR4 individually in neurons. Mapping experiments revealed that α‐Actinin‐1 and IQGAP1 bind to the same region within the C‐terminus of GluR4 that contains a previously identified PKA phosphorylation site, Ser842, phosphorylation of which is regulated by synaptic activity. Interestingly, the phosphorylation of Ser842 differentially regulates interactions of GluR4 with α‐Actinin‐1 and IQGAP1; phosphorylation strongly inhibits interaction of GluR4 with α‐Actinin‐1 but has little effect on its interaction with IQGAP1. These results suggest that α‐Actinin‐1 and IQGAP1 regulate GluR4 functions via their specific associations with GluR4. In addition, our data indicate that activity‐dependent phosphorylation of GluR4 may regulate its synaptic targeting through phosphorylation‐dependent interactions with α‐Actinin‐1 and IQGAP1.
Characterization and evaluation of microsatellite loci in European hazelnut (Corylus avellana L.) and their transferability to other Corylus species
Authors: BOCCACCI P. , AKKAK A. , BASSIL N. V. , MEHLENBACHER S. A. , BOTTA R.
Published: August 2005

In this work, 18 microsatellite loci were developed in the European hazelnut (Corylus avellana L.) using three enriched genomic libraries. They were evaluated on a set of 20 accessions of this species on the basis of number of alleles (mean: 7.1), expected heterozygosity (mean: 0.67), power of discrimination (mean: 0.77) and polymorphism information content (mean: 0.64). Cross‐species transferability was evaluated using seven other Corylus species. All primer pairs amplified in all species, except for CaT‐C505 in Corylus ferox and CaT‐A114 in Corylus californica.
Development and multiplex PCR amplification of novel microsatellite markers in the White‐tailed Sea Eagle, Haliaeetus albicilla (Aves: Falconiformes, Accipitridae)
Authors: HAILER FRANK , GAUTSCHI BARBARA , HELANDER BJÖRN
Published: August 2005

We report the development of 14 novel polymorphic microsatellite markers cloned from the White‐tailed Sea Eagle, Haliaeetus albicilla, a formerly threatened raptor that has received much conservation attention throughout Eurasia. We also present a protocol for multiplex polymerase chain reaction (PCR) amplification of the loci. Among 40 unrelated H. albicilla individuals from southern Sweden, the markers produced two to eight alleles per locus, and average observed and expected heterozygosities were 0.463 and 0.468, respectively. We further present five microsatellite markers that appeared monomorphic in H. albicilla, but which may be of interest for use in other raptor species.
Development and characterization of microsatellite markers in Tectona grandis (Linn. f)
Authors: VERHAEGEN DANIEL , OFORI DANIEL , FOFANA INZA , POITEL MIREILLE , VAILLANT ALEXANDRE
Published: August 2005

Teak (Tectona grandis Linn. f) is a hardwood species of worldwide reputation. It occurs naturally in India, Thailand, Myanmar and Laos. Fifteen highly polymorphic microsatellite loci were developed from a genomic library enriched for AG/TC repeats. Primers to amplify these loci were tested on 265 individual trees from different teak populations. An average of 14.7 alleles per locus were detected and expected heterozygosity ranged from 0.223 to 0.879. These loci constitute a powerful tool in investigating the mating system, gene flow, parentage analysis and population dynamics for use in sustainable management of teak forests and for in situ conservation purposes.
Di‐ and trinucleotide repeat microsatellites for the parasitoid wasp, Aphidius transcaspicus
Authors: LOZIER J. D. , MILLS N. J. , RODERICK G. K.
Published: August 2005

The Mediterranean parasitoid Aphidius transcaspicus is currently under investigation as a potential biological control agent for the mealy plum aphid, Hyalopterus pruni, in California. To better understand the biology of this parasitoid, including the potential existence of distinct strains or geographic races, we have developed a set of nine di‐ and trinucleotide repeat microsatellite markers. These markers were examined for variability in individuals from throughout the geographic distribution of A. transcaspicus, and we found between three and 19 alleles per locus. These are the first loci developed for A. transcaspicus and they will be of value in studying the population structure of this potential biocontrol agent and for future diagnostics.
Polymorphic microsatellite DNA markers in Bactrocera cacuminata (Hering) (Diptera: Tephritidae)
Authors: SONG SIMON D. , MA JING , HUGHES JANE M.
Published: August 2005

Bactrocera cacuminata (Hering) is a nonpest member of the Bactrocera dorsalis complex offering a platform to check hypotheses extrapolated from the more studied pest species. Six polymorphic microsatellite loci were isolated from enriched genomic libraries constructed using a biotin/streptavidin capture protocol. Allele number varied between three and nine; the expected heterozygosity ranged between 0.29 and 0.81. No significant deviations from Hardy–Weinberg equilibrium or linkage disequilibrium were found. These microsatellite markers have potential to be used to examine population structure and mating systems in this tropical fruit fly.
Characterization of microsatellite loci in longnose dace (Rhinichthys cataractae) and interspecific amplification in five other Leuciscinae species
Authors: GIRARD PHILIPPE , ANGERS BERNARD
Published: August 2005

The longnose dace (Rhinichthys cataractae) appears as a relevant model to address environmental and ecological issues in an evolutionary perspective. Eleven microsatellite markers were characterized for this species. Eight of these loci were highly polymorphic for populations of this species. Between four to 10 loci were also successfully amplified in five closely related species. These markers are believed to be valuable tools for genetic analysis of populations of longnose dace and other Leuciscinae species.
Early Cambrian crustal shortening and a clockwise P–T–t path from the southern Prince Charles Mountains, East Antarctica: implications for the formation of Gondwana
Authors: BOGER S. D. , WILSON C. J. L.
Published: August 2005

Cambrian orogenesis (550–490 Ma) in the Lambert Province of the southern Prince Charles Mountains resulted in three successive stages of deformation. The earliest of these deformations resulted in the development of a layer‐parallel foliation (S1) that was folded into macro‐scale recumbent folds (F2). Subsequent deformation buckled the rocks into long‐wavelength (c. 20 km), SW‐ to NW‐trending antiformal closures (F3) mostly separated from each other by west to SW trending, steeply dipping, high‐strain zones. Metapelitic rocks from the region are divisible into two compositional types: a high‐Al, ‐Fe and ‐K type and a high‐Mg, ‐Ca and ‐Na type. In rocks of both composition, relic staurolite preceded the formation of upper amphibolite facies garnet + biotite + sillimanite ± muscovite mineral assemblages that record peak pressures and temperatures of c. 650–700 °C and 6–7 kbar. Subsequent decompression of c. 3 kbar is implied from texturally late plagioclase and a reduction in the modal abundance of garnet in the high‐Al, ‐Fe and ‐K metapelites, and from texturally late cordierite in the more magnesium rocks. This clockwise P–T–t path, with prograde heating followed by rapid decompression, is: (i) equivalent to that recorded in the same‐aged rocks at Prydz Bay located 600 km to the north, and (ii) similar to the modelled response of the crust to thickening following continent–continent collision. These results indicate that large areas of East Antarctica were thickened and rapidly exhumed, probably in response to collisional orogenesis during the Early Cambrian. This supports the inference that Early Cambrian orogenesis in the Prydz Bay–Prince Charles Mountains region of East Antarctica marks one of the fundamental lithospheric boundaries within Gondwana.
The Old‐Old‐Old
Authors: Steel Knight
Published: August 2005

Geriatricians have long distinguished aging from disease. Yet the separation of these two processes and these in turn from the effects of the environment is most difficult. Therefore, as the possibility of manipulating the aging process is considered, what the elder of tomorrow will look like can only be speculated about. Might it be possible to alter the effect of aging on one organ system and not others? Should we be stating that disease appears a certain number of years before the end of life rather than noting its onset from the moment of birth? If the phenomenon of aging can be manipulated, the distinction between aging and disease may become increasingly difficult except for conditions clearly caused by an infectious agent or an environmental toxin.
Plessy as “Passing”: Judicial Responses to Ambiguously Raced Bodies in Plessy v. Ferguson
Authors: Golub Mark
Published: August 2005

The Supreme Court's decision in Plessy v. Ferguson (1896) is infamous for its doctrine of “separate but equal,” which gave constitutional legitimacy to Jim Crow segregation laws. What is less-known about the case is that the appellant Homer Plessy was, by all appearances, a white man. In the language of the Court, his “one-eighth African blood” was “not discernible in him.” This article analyzes Plessy as a story of racial “passing.” The existence of growing interracial populations in the nineteenth century created difficulties for legislation designed to enforce the separation of the races. Courts were increasingly called upon to determine the racial identity of particular individuals. Seen as a judicial response to racial ambiguity, Plessy demonstrates the law's role not only in the treatment of racial groups, but also in the construction and maintenance of racial categories.
The Local Role in Homeland Security
Authors: Thacher David
Published: August 2005

There has been considerable discussion since September 11 of the enormous resource that local police potentially represent in the fight against terrorism. This article identifies limits to the local role in homeland security by analyzing a case study of Dearborn, Michigan. Partly because Dearborn is home to one of the largest concentrations of Arabs in the United States, its experience with homeland security highlights two kinds of burdens that cities incur when they engage in proactive surveillance to identify potential terrorists: damage to their reputation (since police surveillance implies that its objects are not trustworthy) and damage to police legitimacy (since new surveillance may undermine trust between police and the community). Because the benefits of efforts to identify terrorists typically accrue to jurisdictions other than the one that engages in it—unlike street crime, terrorism is a national or even international problem—local governments have little reason to pursue it. Instead, cities such as Dearborn have reason to emphasize what I call the “community protection” aspects of homeland security, such as target hardening and emergency response. This finding has more general implications for our understanding of the police role and the politics of policing, showing how both are shaped by the structural location police occupy in federalist systems of government.
Functional ability at age 75: is there an impact of physical inactivity from middle age to early old age?
Authors: Christensen U. , Støvring N. , Schultz‐Larsen K. , Schroll M. , Avlund K.
Published: August 2005

The aim of this study is to analyze the impact of physical inactivity from middle age to early old age on functional ability at age 75. Physical activity is measured both as cumulated activity from age 50 to 60 to 70 and at three separate points in time.

Three hundred eighty‐seven men and women born in 1914 and living in seven municipalities in the western part of the County of Copenhagen were followed for 25 years with examinations in 1964, 1974, 1984 and 1989. Analyses were conducted with physical inactivity as an independent variable (accumulated and separately for each point in time) and smoking, sex, school education, household composition, chronic disease at baseline and functional ability at age 70 as possible confounders. There was a strong association between physical inactivity at age 70 and disability at age 75. However, the analyses showed no effect of cumulated physical inactivity from age 50 to 60 to 70 on disability at age 75 when adjusting for functional ability at age 70. Physical inactivity is a risk factor for disability among old people. Thus, old people should be encouraged to take up and maintain physical training throughout the aging process.
The impact of cigarette/tobacco smoking on oral candidosis: an overview
Authors: Soysa NS , Ellepola ANB
Published: August 2005

Smoking is associated with a variety of changes in the oral cavity. Cigarette smoke has effects on saliva, oral commensal bacteria and fungi, mainly Candida, which causes oral candidosis, the most common opportunistic fungal infection in man. How cigarette smoke affects oral Candida is still controversial. This brief overview is an attempt to address the clinical findings on the relationship between smoking and oral candidosis and possible mechanisms of pathogenicity.
Paraneoplastic pemphigus: a case report and review of literature
Authors: Tilakaratne WM , Dissanayake M
Published: August 2005

Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease frequently associated with lymphoproliferative disorders. The rare combination of the disease with other malignancies such as different types of carcinomas, sarcomas, melanoma and skin tumours has also been reported. Most patients develop very severe oral ulceration and conjunctival ulceration with or without genital ulceration resembling the features of Steven's Johnson's syndrome or most severe forms of drug eruptions. The possibility of PNP should be borne in mind when a patient presents with extensive oral ulceration if clinical, histopathological and results of direct immunofluorescence are not pathognomonic for a specific diagnosis. The issue becomes even more important as some patients with PNP have no diagnosed malignancy at the time of presentation. We document a case of PNP in a 29‐year‐old female who suffers from non‐Hodgkin's lymphoma.
Aggrecanase analysis of synovial fluid of temporomandibular joint disorders
Authors: Yoshida K , Takatsuka S , Tanaka A , Hatada E , Nakamura H , Nakagawa K , Okada Y
Published: August 2005

Objectives:  To determine whether or not aggrecanase in synovial fluid can be used as a biochemical marker in the diagnosis of temporomandibular joint disorder (TMJD).

Materials and methods:  Forty‐four samples of synovial fluid were obtained from 35 patients with internal derangement or osteoarthritis and 15 control samples from 10 asymptomatic volunteers. Aggrecanase in the synovial fluid was examined by immunoblotting.

Result:  The incidence of aggrecanase expression in TMJD group were significantly higher than that in the normal control group (P < 0.05). Those with severe OA and anterior disc displacement without reduction showed significantly high expression of aggrecanase compared with other disease subgroups (P < 0.05).

Conclusion:  These findings suggested that aggrecanase could be a potential biochemical marker for cartilage degeneration in the TMJD.
Adenosine deaminase and 5′‐nucleotidase activities in saliva from patients with oral and laryngeal cancer
Authors: Saracoglu U , Guven O , Durak I
Published: August 2005

Objective:  The aim of this study was to evaluate saliva's activities of adenosine deaminase (ADA) and 5′‐nucleotidase (5′‐NT) enzymes and their utility as diagnostic and therapeutic markers in oral and laryngeal cancer.

Materials and methods:  Pre‐ and post‐operative saliva's activities of ADA and 5′‐NT enzymes were measured in patients with squamous cell oral (n = 10) and laryngeal cancer (n = 17) and compared with control saliva samples (n = 19).

Results:  The ADA was found to be lower in saliva of the patients with oral cancer compared with the laryngeal cancer and controls. However, no significant differences were found between pre‐ and post‐operative values for both enzymes in the patient groups. We also could not find statistically significant differences between saliva's activities of 5′‐NT in patients and control subjects.

Conclusions:  Low activity of ADA observed in saliva of the patients with oral cancer has been suggested as a compensatory mechanism against rapid purine and DNA metabolism in cancer cells. The current study does not support the hypothesis that saliva's activities of these enzymes may be used as additional diagnostic and prognostic cancer markers.
3-D Numerical Simulation of Blood Flow Through Models of the Human Aorta
Authors: Morris L. , Delassus P. , Callanan A. , Walsh M. , Wallis F. , Grace P. , McGloughlin T.
Published: August 2005

A Spiral Computerized Tomography (CT) scan of the aorta were obtained from a single subject and three model variations were examined. Computational fluid dynamics modeling of all three models showed variations in the velocity contours along the aortic arch with differences in the boundary layer growth and recirculation regions. Further downstream, all three models showed very similar velocity profiles during maximum velocity with differences occurring in the decelerating part of the pulse. Flow patterns obtained from transient 3-D computational fluid dynamics are influenced by different reconstruction methods and the pulsatility of the flow. Caution is required when analyzing models based on CT scans.
A Method for Measurement of Joint Kinematics in Vivo by Registration of 3-D Geometric Models With Cine Phase Contrast Magnetic Resonance Imaging Data
Authors: Barrance Peter J. , Williams Glenn N. , Novotny John E. , Buchanan Thomas S.
Published: August 2005

A new method is presented for measuring joint kinematics by optimally matching modeled trajectories of geometric surface models of bones with cine phase contrast (cine-PC) magnetic resonance imaging data. The incorporation of the geometric bone models (GBMs) allows computation of kinematics based on coordinate systems placed relative to full 3-D anatomy, as well as quantification of changes in articular contact locations and relative velocities during dynamic motion. These capabilities are additional to those of cine-PC based techniques that have been used previously to measure joint kinematics during activity. Cine-PC magnitude and velocity data are collected on a fixed image plane prescribed through a repetitively moved skeletal joint. The intersection of each GBM with a simulated image plane is calculated as the model moves along a computed trajectory, and cine-PC velocity data are sampled from the regions of the velocity images within the area of this intersection. From the sampled velocity data, the instantaneous linear and angular velocities of a coordinate system fixed to the GBM are estimated, and integration of the linear and angular velocities is used to predict updated trajectories. A moving validation phantom that produces motions and velocity data similar to those observed in an experiment on human knee kinematics was designed. This phantom was used to assess cine-PC rigid body tracking performance by comparing the kinematics of the phantom measured by this method to similar measurements made using a magnetic tracking system. Average differences between the two methods were measured as 2.82 mm rms for anterior∕posterior tibial position, and 2.63 deg rms for axial rotation. An inter-trial repeatability study of human knee kinematics using the new method produced rms differences in anterior∕posterior tibial position and axial rotation of 1.44 mm and 2.35 deg. The performance of the method is concluded to be sufficient for the effective study of kinematic changes caused to knees by soft tissue injuries.
Preclinical Testing of Femoral Hip Components: An Experimental Investigation With Four Prostheses
Authors: Britton John R. , Prendergast Patrick J.
Published: August 2005

Existing standards for the preclinical testing of femoral hip implants have been successful in the objective of guaranteeing the implant’s fatigue strength. There is a need for an experimental test which could ensure prostheses were not susceptible to aseptic loosening. In this study we measure the relative movement between the prosthesis and the bone of four different cemented femoral component designs in in vitro tests. The aim is to determine if differences can be distinguished and whether the differences correlate with clinical performance. The four designs are the Charnley (DePuy International Ltd., UK), the Exeter (Stryker Osteonics Howmedica Corp., USA), the Lubinus SPII (Waldemar-Link GmbH, Germany), and the Müller Curved (JRI Ltd, UK). Five tests were carried out for each femoral component type, giving a total of 20 tests, and their permanent relative displacement (termed migration) and recoverable (i.e., elastic) relative displacement (termed inducible displacement) monitored over one million loading cycles. Considerable variation occurred in the tests. Nonetheless, most femoral components migrated medially, posteriorly, and distally. Most also rotated into varus. Translations of the Charnley (64microns) and Lubinus (67microns) implants were less than the Müller (72microns) and Exeter (94microns) implants, but this difference is not statistically significant. Most of the femoral components had rapid early migration followed by slower steady-state migration. With regard to the steady state inducible displacements of the prostheses, those of the Charnley, Exeter, and Lubinus decreased or were stable with respect to time, whilst those of the Müller typically increased with respect to time. It is concluded that migration is not a suitable basis for in vitro comparison of prosthesis designs. However, inducible displacement trends provide a clinically comparable performance ranking.
Correlation of HSP70 Expression and Cell Viability Following Thermal Stimulation of Bovine Aortic Endothelial Cells
Authors: Rylander Marissa Nichole , Diller Kenneth R. , Wang Sihong , Aggarwal Shanti J.
Published: August 2005

Thermal preconditioning protocols for cardiac cells were identified which produce elevated HSP70 levels while maintaining high cell viability. Bovine aortic endothelial cells were heated with a water bath at temperatures ranging from 44to50°C for periods of 1-30min. Thermal stimulation protocols were determined which induce HSP70 expression levels ranging from 2.3 to 3.6 times the control while maintaining cell viabilities greater than 90%. An Arrhenius injury model fit to the cell damage data yielded values of A=1.4×1066s−1 and Ea=4.1×105J∕mol. Knowledge of the injury parameters and HSP70 kinetics will enhance dosimetry guideline development for thermal stimulation of heat shock proteins expression in cardiac tissue.
Community Structure of Corals and Reef Fishes at Multiple Scales
Authors: Connolly Sean R. , Hughes Terry P. , Bellwood David R. , Karlson Ronald H.
Published: August 2005

Distributions of numerical abundance and resource use among species are fundamental aspects of community structure. Here we characterize these patterns for tropical reef fishes and corals across a 10,000-kilometer biodiversity gradient. Numerical abundance and resource-use distributions have similar shapes, but they emerge at markedly different scales. These results are consistent with a controversial null hypothesis regarding community structure, according to which abundance distributions arise from the interplay of multiple stochastic environmental and demographic factors. Our findings underscore the importance of robust conservation strategies that are appropriately scaled to the broad suite of environmental processes that help sustain biodiversity.
Molecular Mechanism for Switching of
P. falciparum
Invasion Pathways into Human Erythrocytes
Authors: Stubbs Janine , Simpson Ken M. , Triglia Tony , Plouffe David , Tonkin Christopher J. , Duraisingh Manoj T. , Maier Alexander G. , Winzeler Elizabeth A. , Cowman Alan F.
Published: August 2005

The malaria parasite,
Plasmodium falciparum
, exploits multiple ligand-receptor interactions, called invasion pathways, to invade the host erythrocyte. Strains of
P. falciparum
vary in their dependency on sialated red cell receptors for invasion. We show that switching from sialic acid–dependent to –independent invasion is reversible and depends on parasite ligand use. Expression of
P. falciparum
reticulocyte–binding like homolog 4 (PfRh4) correlates with sialic acid–independent invasion, and PfRh4 is essential for switching invasion pathways. Differential activation of PfRh4 represents a previously unknown mechanism to switch invasion pathways and provides
P. falciparum
with exquisite adaptability in the face of erythrocyte receptor polymorphisms and host immune responses.
Nuclear Reprogramming of Somatic Cells After Fusion with Human Embryonic Stem Cells
Authors: Cowan Chad A. , Atienza Jocelyn , Melton Douglas A. , Eggan Kevin
Published: August 2005

We have explored the use of embryonic stem cells as an alternative to oocytes for reprogramming human somatic nuclei. Human embryonic stem (hES) cells were fused with human fibroblasts, resulting in hybrid cells that maintain a stable tetraploid DNA content and have morphology, growth rate, and antigen expression patterns characteristic of hES cells. Differentiation of hybrid cells in vitro and in vivo yielded cell types from each embryonic germ layer. Analysis of genome-wide transcriptional activity, reporter gene activation, allele-specific gene expression, and DNA methylation showed that the somatic genome was reprogrammed to an embryonic state. These results establish that hES cells can reprogram the transcriptional state of somatic nuclei and provide a system for investigating the underlying mechanisms.
TUNNEL DIODE/TRANSISTOR DIFFERENTIAL COMPARATOR
Authors: LIU QINGMIN , SUTAR SURAJIT , SEABAUGH ALAN
Published: August 2005

A new tunnel diode/transistor circuit topology is reported, which both increases speed and reduces power in differential comparators. This circuit topology is of special interest for use in direct digital synthesis applications. The circuit topology can be extended to provide performance improvements in high speed logic and signal processing applications. The circuits are designed based on InP/GaAsSb double heterojunction bipolar transistors and AlAs/InGaAs/AlAs resonant tunneling diodes. A self-aligned and scalable fabrication approach using nitride sidewalls and chemical mechanical polishing is outlined.
NOISE AND THZ RECTIFICATION CHARACTERISTICS OF ZERO-BIAS QUANTUM TUNNELING SB-HETEROSTRUCTURE DIODES
Authors: LUUKANEN ARTTU , GROSSMAN ERICH N. , MOYER HARRIS P. , SCHULMAN JOEL N.
Published: August 2005

The Sb -heterostructure quantum tunneling diode, fabricated from epitaxial layers of InAs and AlGaSb , is a recently proposed device for direct detection and mixing in the submillimeter wavelength range. These diodes exhibit especially high curvature in the current-voltage characteristic that produces the rectification or mixing without bias. Operation without bias is a highly desirable feature as the device does not suffer from large 1/f noise, a major shortcoming in other devices such as Schottky barrier diodes or resistive room temperature bolometers. In this paper we present the noise characteristics of the diode as a function of the bias voltage. At room temperature and zero bias, the device demonstrates a Johnson noise limited intrinsic noise equivalent power of 1 pW/Hz1/2. In addition to the noise measurements, we present the detection characteristics of the diode at a frequency of 2.5 THz. The measured THz laser response deviates from conventional theoretical prediction based on pure rectification. The reasons for the discrepancy will be discussed.
ELECTRICAL EFFECTS OF DNA MOLECULES ON SILICON FIELD EFFECT TRANSISTOR
Authors: XUAN G. , KOLODZEY J. , KAPOOR V. , GONYE G.
Published: August 2005

Much research has been devoted to the field of DNA detection for biotechnology and medical diagnostics. Conventionally, this has involved lab-scale large instruments such as fluorescent microscope, with DNA binding and tagging. Recently, however, the possibility of label-free, rapid, sensitive and miniaturized DNA detection electronically has attracted increasing interest in the field. To investigate the feasibility of DNA detection by the semiconductor field effect without tagging or binding agents, we studied the effects of DNA molecules directly on the gate oxide of field effect transistors (FET). DNA solution was deposited onto the gate region of conventional silicon FET devices without gate metal, and current-voltage measurements were performed. Our work showed that the presence of DNA molecules in an aqueous solution on the gate decreased channel current I ds and increased threshold voltage. With increasing concentration in the solution, the threshold voltage increased monotonically. We observed that the channel current was reduced systematically during the hybridization of complementary DNA strands. The mechanism that induced the threshold voltage shift is attributed to the negative charges the DNA molecules carry and to changes in work function (Fermi Energy). Our results showed the possibility that field effect transistors may provide a vehicle for a label-free, miniaturized and semiconductor-based DNA detector.
ANALYSIS OF OPERATIONAL TRANSCONDUCTANCE AMPLIFIER FOR APPLICATION IN GHz FREQUENCY RANGE
Authors: GHORI A. , GHOSH P.
Published: August 2005

Operational Transconductance Amplifier (OTA) is an excellent current mode device suited very well for VLSI implementation. In this contribution we report realization of OTA using Silicon-On-Insulator (SOI) structure based MOSFETs and compared them to OTA designed with bulk MOSFET. SOI based OTA outperformed bulk MOSFET OTA giving close to 10 GHz improvement in high frequency f T . A band-pass filter was implemented with SOI based OTA with a center frequency of 7 GHz and a bandwidth of 480 kHz.
High Speed 0.9 μm Lateral p-i-n Photodetectors Fabricated in a Standard Commercial GaAs VLSI Process
Authors: GIZIEWICZ WOJCIECH P. , FONSTAD CLIFTON G. , PRASAD SHEILA
Published: August 2005

Lateral detectors fabricated in an unmodified commercial GaAs VLSI process are presented. The detectors exhibit previously observed characteristic sensitivity and capacitance properties. High speed measurements indicate a bandwidth in excess of 4 GHz.
SELF-GUIDING IN LOW-INDEX-CONTRAST PLANAR PHOTONIC CRYSTALS
Authors: CHEN CAIHUA , LU ZHAOLIN , SHI SHOUYUAN , PRATHER DENNIS W.
Published: August 2005

This paper presents a new lateral confinement mechanism based on the self-collimation effect in planar photonic crystals (PhCs). In this mechanism, planar PhCs with approximately flat equifrequency contours (EFCs) are utilized for laterally confining the light and total internal reflection (TIR) is used for the vertical confinement. Since this mechanism relies on dispersion engineering, no photonic band gap nor defect modes are required. Using this approach, it is possible to engineer flat EFCs completely below the light cone using relatively low-index-contrast material systems. Therefore, in this work we first engineer a low-index-contrast planar PhC with approximately flat EFCs in the first band, which is always below the light cone. Then, we investigate the lateral divergence of self-guided beams in this structure using the plane wave method (PWM). It is found that light with a narrow band frequency in the first band can be very well self-confined laterally.
THICK GaN LAYER GROWN BY Ga VAPOR TRANSPORT TECHNIQUE
Authors: WU HUAQIANG , KONKAPAKA PHANIKUMAR , MAKAROV YURI , SPENCER MICHAEL G.
Published: August 2005

Using a novel Ga vapor transport technique, thick gallium nitride layers have been deposited on a 3-6 μm GaN film grown on sapphire substrate via hydride vapor phase epitaxy (HVPE). GaN powder was successfully used as a stable Ga source material for the growth. A growth rate of greater than 200 μm/hr was achieved by optimizing the growth temperature and the reactant gas flow rates. This growth rate is as high as that achieved by HVPE. The GaN layers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Atomic Force Microscopy (AFM).
SELECTIVE DRY ETCHING OF GaN OVER AlGaN IN BCL3/SF6 MIXTURES
Authors: BUTTARI D. , CHINI A. , CHAKRABORTY A. , MCCARTHY L. , XING H. , PALACIOS T. , SHEN L. , KELLER S. , MISHRA U. K.
Published: August 2005

Inductively coupled plasma (ICP) etching of GaN with high selectivity over Al .22 Ga .78 N in BCl 3/ SF 6 mixtures has been studied. Selectivity and surface morphology were investigated over a wide range of pressures (3.75–37.5mTorr), RF powers (30–120 W), ICP powers (100–400 W), and SF 6/ BCl 3 ratios (0.1–0.7). Higher pressures, lower dc biases, and higher SF 6/ BCl 3 ratios increased the GaN to AlGaN selectivity. Selectivities up to 25 were measured by laser interferometry. A root mean square (rms) surface roughness of 0.67 nm was measured by atomic force microscopy (AFM) after removal of 0.5 μm from a GaN template (process selectivity: 15, as-grown rms surface roughness: 0.56 nm). A degradation in surface morphology, with the gradual formation of pits, was observed for selectivities above 10.
TRAP BEHAVIOR IN AlGaN/GaN HEMTs BY POST-GATE-ANNEALING
Authors: KIM HYEONGNAM , LEE JAESUN , LU WU
Published: August 2005

Trapping effects are investigated to examine the post-gate annealing effects on AlGaN/GaN high-mobility electron transistors (HEMTs) using pulsed I-V and transient measurements. In the unannealed devices, shallow traps are identified, which have an activation of 38 meV at a drain bias of 7 V. The time constant of these traps is determined to be ~0.5 μs. Devices annealed at 400°C for 10 minutes have a significantly smaller number of traps. However, a small number of traps with a longer time constant of 9.2 μs are created or activated during post-gate annealing. 20-minute annealing at 400°C leads to the increase of the number of traps with emission time constants of 21.6 μs and 1.25 ms. The breakdown voltage improvement by post-gate annealing is attributed to the removal or significant reduction of the shallow level traps.
UNSTRAINED InAlN/GaN HEMT STRUCTURE
Authors: NEUBURGER M. , ZIMMERMANN T. , KOHN E. , DADGAR A. , SCHULZE F. , KRTSCHIL A. , GÜNTHER M. , WITTE H. , BLÄSING J. , KROST A. , DAUMILLER I. , KUNZE M.
Published: August 2005

InAlN has been investigated as barrier layer material for GaN -HEMT structures, potentially offering higher sheet charge densities [1] and higher breakdown fields [2]. Lattice matched growth of the barrier layer can be achieved with 17 % In content, avoiding piezo polarization. In this configuration the sheet charge density is only induced by spontaneous polarization. First experimental results of unpassivated undoped samples realized on 111- Si substrate exceed a DC output current density of 1.8 A/mm for a gate length of 0.5 μm. Small signal measurements yield a f t = 26 GHz and f max = 14 GHz , still limited by the residual conductivity of the Si -substrate. A saturated output power at 2 GHz in class A bias point yielded a density of 4.1 W/mm at V DS = 24 V .
DEPENDENCE OF ELECTRON MOBILITY ON EPI CHANNEL DOPING IN GaN MOSFETS
Authors: RUAN J. , MATOCHA K. , HUANG W. , CHOW T. P.
Published: August 2005

The field-effect mobility and Hall mobility of electrons in lateral, accumulation-mode GaN MOSFETs have been comparatively studied. The devices were fabricated on three different samples, Sample A consisting of 70 nm n-type ( N D = 5×1017 cm -3) GaN and Sample B 0.5 μm unintentionally doped ( N D < 1×1016 cm -3) GaN , both on 2 μm undoped Al 0.35 Ga 0.65 N grown on the n +- SiC substrates and Sample C 3 μm unintentionally doped GaN on the sapphire substrate. The maximal field-effect mobilities are 120 cm2/V-s, 90 cm2/V-s and 53 cm2/V-s respectively in the three samples. The Hall mobility is also measured for Samples A & B and reaches a maximal value of 160 cm2/V-s.
FABRICATION OF SELF-ALIGNED T-GATE AlGaN/GaN HIGH ELECTRON MOBILITY TRANSISTORS
Authors: LEE JAESUN , LIU DONGMIN , KIM HYEONGNAM , SCHUETTE MICHAEL L. , LU WU , FLYNN JEFFREY S. , BRANDES GEORGE R.
Published: August 2005

Self-aligned AlGaN/GaN high electron mobility transistors (HEMTs) are fabricated and the direct current and radio frequency small signal performance of self-aligned devices is characterized in comparison with non-self-aligned devices. An ultra-thin Ti/Al/Ti/Au ohmic metal scheme is used for gate to source and drain self-alignment. To suppress the gate leakage current, the ohmic contact annealing of self-aligned devices is performed in a furnace. The self-aligned devices with 0.25 μm gate-length and 100 μm gate-width exhibit good pinch-off characteristics. The maximum drain current at a gate bias of 1 V is 620 mA/mm for self-aligned HEMTs, and 400 mA/mm for non-self-aligned devices, respectively. A maximum extrinsic transconductance of 146 mS/mm is measured in self-aligned devices, while non-self-aligned HEMTs show only a peak g m of 92 mS/mm. The self-aligned devices exhibit an extrinsic f T of 39 GHz and an f MAX of 130 GHz, whereas non-self-aligned HEMTs show an f T of 15 GHz and an f MAX of 35 GHz.
A NEW FIELD-PLATED GaN HEMT STRUCTURE WITH IMPROVED POWER AND NOISE PERFORMANCE
Authors: XU HONGTAO , SANABRIA CHRISTOPHER , CHINI ALESSANDRO , WEI YUN , HEIKMAN STEN , KELLER STACIA , MISHRA UMESH K. , YORK ROBERT A.
Published: August 2005

Field-plated structures can dramatically improve power capacity of GaN HEMT devices. In this paper, two different field-plated GaN HEMT structures will be demonstrated and compared to each other. The results show that a new GaN HEMT structure improves both power and noise performance without additional processing or costs.
NOISE CHARACTERISTICS OF FIELD-PLATED GAN HEMTS
Authors: WU Y.-F. , MOORE M. , WISLEDER T. , CHAVARKAR P. M. , PARIKH P. , SAXLER A.
Published: August 2005

Investigation into field-plated GaN HEMTs has revealed that, although addition of the field plate reduces cutoff frequencies, noise figure actually improves. An analysis is presented to explain this phenomenon, which is related to the trade-off between gate-drain capacitance and gate conductance.
HIGH POWER, DRIFT-FREE 4H-SiC PIN DIODES
Authors: DAS MRINAL K. , SUMAKERIS JOSEPH J. , HULL BRETT A. , RICHMOND JIM , KRISHNASWAMI SUMI , POWELL ADRIAN R.
Published: August 2005

The path to commercializing a 4H - SiC power PiN diode has faced many difficult challenges. In this work, we report a 50 A, 10 kV 4H - SiC PiN diode technology where good crystalline quality and high carrier lifetime of the material has enabled a high yielding process with V F as low as 3.9 V @ 100 A/cm2. These 10 kV diodes demonstrate pulsed current handling capability up to 328 A which represents over 3 MW of pulsed power. Furthermore, incorporation of two independent basal plane dislocation reduction reduction processes (LBPD 1 and LBPD 2) have produced a large number of devices that exhibit a high degree of forward voltage stability. The more benign LBPD 2 process yields wafers with better reverse blocking capability resulting in a total yield (forward, 10 kV blocking, and drift) of >20% for 8.7 mm × 8.7 mm power PiN diode chips—the largest SiC chip reported to date.
Analysis of the Semileptonic Decay $D^0 \to \overline{K}^0 \pi^- \mu^+ \nu$
Authors:   On behalf of the FOCUS-E831 collaboration., Segoni Ilaria
Published: August 2005

Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay [Formula: see text]. Using a model that includes a [Formula: see text] S -wave component, we measure the form factor ratios to be rv = 1.706 ± 0.677 ± 0.342 and r2 = 0.912 ± 0.370 ± 0.104 and the S -wave amplitude to be A = 0.347 ± 0.222 ± 0.053 GeV -1. Finally, we measure the vector semileptonic branching ratio [Formula: see text].
Search for b → dγ decays
Authors:   for the Belle Collaboration., Mohapatra Debabrata
Published: August 2005

We report search results for flavor-changing neutral current process b → dγ with a data sample containing 275 million B meson pairs accumulated at ϒ(4S) resonance. We studied the exclusive decays B+ → ρ+γ, B0 → ρ0γ and B0 → ωγ, and find no significant signal. We set an upper limit for combined branching fraction [Formula: see text] at 90% confidence level.
B LIFETIME MEASUREMENTS FROM DØ
Authors:   On behalf of the DØ Collaboration., DE LA CRUZ BURELO EDUARD
Published: August 2005

We present the more recent measurements of the B hadrons lifetimes and its ratios, performed using 250 pb-1 of the Run II data collected with the DØ detector at Tevatron.
Evidence for $B^{(*)}_s$ Production at the ϒ(5S)
Authors:   Representing the CLEO Collaboration., Sia R.
Published: August 2005

Based on data collected by the CLEO III detector at CESR, we started a series of investigations to open the mysteries of the ϒ(5 S ) resonance decay properties. Bs mesons are expected to decay predominantly into Ds meson, while the lighter B mesons decay into Ds only about 10% of the time. We exploit this difference to present the first evidence of a substantial production of Bs mesons at the ϒ(5 S ) resonance. We make here a preliminary model dependent estimate of the ratio of [Formula: see text] to the total [Formula: see text] quark pair production at the ϒ(5 S ) energy to be (21 ± 3 ± 9)%.
STUDIES OF $\Xi^0_c$ PRODUCTION AND DECAYS AT BABAR
Authors: ZIEGLER VERONIQUE
Published: August 2005

The production of [Formula: see text]'s from [Formula: see text] continuum and from B decays is studied using 116 fb-1 of data collected by the BABAR detector. A measurement of the ratio of the branching fractions of the [Formula: see text] decaying into Ξ-π+ and Ω-K+ final states is presented.
Search for rare and forbidden decays of D0 → ℓ+ℓ-
Authors:   for the BABAR Collaboration., Chen Chunhui
Published: August 2005

We report on a search for the flavor-changing neutral current decays D0 → e+e- and D0 → μ+μ-, and the lepton-flavor violating decay D0 → e±μ∓. The measurement is based on 122 fb-1 of data collected by the BABAR detector at the PEP-II asymmetric e+e- collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90% confidence level, are 1.2 × 10-6 for D0 → e+e-, 1.3 × 10-6 for D0 → μ+μ-, and 8.1 × 10-7 for D0 → e±μ∓.