bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of the
Vibrio vulnificus hupA
Gene by Temperature Alteration and Cyclic AMP Receptor Protein and Evaluation of Its Role in Virulence
Authors: Oh Man Hwan , Lee Sung Min , Lee Dong Hwan , Choi Sang Ho
Published: January 2009

Availability of free iron is extremely limited in the mammalian host, and the acquisition of iron in the host is essential for successful infection by pathogenic bacteria. Expression of many genes involved in acquiring iron is regulated in response to the level of iron availability, and iron regulation is mediated by Fur. In this study, cellular levels of
Vibrio vulnificus
HupA, a heme receptor protein, and the
hupA
transcript were found to increase in cells grown at 40°C compared to cells grown at 30°C. The results suggested that change in growth temperature, in addition to iron availability, is an environmental cue controlling the expression of the
hupA
gene. The influence of global regulatory proteins on the expression of
hupA
was examined, and the cyclic AMP receptor protein (CRP) was found to activate the expression of
hupA
at the transcriptional level. CRP exerts its effects by directly binding to DNA upstream of the
hupA
promoter P

hupA

, and a CRP binding site, centered at 174 bp upstream of the transcription start site, was identified by a DNase I protection assay. Finally, a
hupA
mutant showed reduced virulence in mice and in tissue cultures, in which growth of the
hupA
mutant was impaired, indicating that HupA of
V. vulnificus
is essential for survival and multiplication during infection.
Genetic Polymorphisms of Mannose-Binding Lectin Do Not Influence Placental Malaria but Are Associated with Preterm Deliveries
Authors: Thévenon Audrey D. , Leke Rose G. F. , Suguitan Amorsolo L. , Zhou James A. , Taylor Diane Wallace
Published: January 2009

During pregnancy,Plasmodium falciparum-infected erythrocytes (IE) sequester in the placenta where they induce pathology and increase the risk of low-birth-weight (LBW) babies. The innate immune mediator, mannose-binding lectin (MBL), enhances phagocytosis of pathogens. Since MBL is reported to bind to IE, we hypothesized that it might aid in clearance of IE from the placenta, thereby reducing the risk of LBW babies. To test this hypothesis, molecular genotyping was used to detect polymorphisms at codon 57 (A/C) in exon 1 ofMBL2in 401 pregnant Cameroonian women, with or without placental malaria, who had LBW and normal-weight babies. Polymorphisms in the promoter region at positions −550 (H/L), −221 (X/Y), and +4 (P/Q) were also determined, and plasma MBL levels were measured during pregnancy and at delivery. The expected correlation between genotype and plasma MBL levels was confirmed. However, asymptomatic infections were not associated with an increase in MBL levels in the peripheral blood, and MBL levels were similar in the placental and cord blood of women with or without placental malaria at delivery. There was no evidence that MBL levels at delivery were associated with malaria-related poor pregnancy outcomes. Women with the LXPA haplotype, however, were more likely to have LBW babies, but the risk was not related to malaria. These results do not support the hypothesis that MBL aids in the clearance of parasites from the placenta but suggest that Cameroonian women with LXPA are at risk of having LBW babies due to other causes.
Effect of Chlamydiaphage φCPG1 on the Course of Conjunctival Infection with “
Chlamydia caviae
” in Guinea Pigs
Authors: Rank Roger G. , Bowlin Anne K. , Cané Stefania , Shou Huizhong , Liu Zhi , Nagarajan Uma M. , Bavoil Patrik M.
Published: January 2009

Over the last several years, four different phages of chlamydiae, in addition to a phage associated with
Chlamydia psittaci
isolated from an ornithosis infection in ducks over 25 years ago, have been described and characterized. While these phages and their chlamydial host specificities have been characterized in vitro, there is virtually nothing known about the interaction of the phage with chlamydiae in their natural animal host. φCPG1 is a lytic phage specific for “
Chlamydia caviae
,” which is a natural parasite of the guinea pig. In this study, guinea pigs were inoculated in the conjunctiva with suspensions of φCPG1 and
C. caviae
and the effect on the development of pathology and on the course of chlamydial infection in the conjunctiva was determined. The presence of phage delayed the appearance of the peak level of chlamydiae in the animal and decreased the pathological response. Evidence for replication of the phage in
C. caviae
in the conjunctival tissue was observed. Modifying the ratio of phage to chlamydiae altered the course of infection and affected phage replication. There was no evidence for the phage increasing the virulence of
C. caviae
infection.
Role of Complement in Host Defense against Pneumococcal Otitis Media
Authors: Sabharwal Vishakha , Ram Sanjay , Figueira Marisol , Park In Ho , Pelton Stephen I.
Published: January 2009

Strategies to limit complement deposition onStreptococcus pneumoniaeare established as virulence features for invasive disease, but their role in respiratory tract infection requires further analysis. We evaluated complement C3 protein deposition on discordantS. pneumoniaeisolates of the same serotype (6A) and their capacity to cause nasopharyngeal (NP) colonization and experimental otitis media (EOM) in an animal model. We compared C3 binding to five 6A isolates from asymptomatic NP carriers with five 6A strains that caused invasive disease, and we observed less C3 (∼10-fold less fluorescence) binding to invasive isolates. We selected two high-level C3-binding carriage and two low-level C3-binding invasive 6A isolates for further study. In the EOM model, 11/12 (92%) ears challenged with a low-level C3-binding 6A strain became infected. Only 2/8 (25%) ears challenged with the discordant high-level C3-binding 6A isolate developed disease (P= 0.005). Results with the second discordant 6A isolate pair were comparable. Cobra venom factor (CoVF) treatment, which depletes C3 and consumes complement, restored virulence of the high-level C3-binding strain; 8/8 (100%) ears in CoVF-treated animals developed EOM compared to only 25% of ears in naïve animals (P= 0.007). These studies demonstrate the critical role for complement evasion in pneumococcal EOM. Colonization with carriage isolates that bound high levels of C3 caused EOM in fewer animals compared to low-level C3-binding invasive strains. Thus, limiting C3 deposition on the surface ofS. pneumoniaecorrelates with increased incidence of EOM following NP colonization and barotrauma in the animal model.
Sex differences in self-reported symptoms after aerobic exercise in non-injured athletes: implications for concussion management programmes
Authors: Gaetz M B , Iverson G L
Published: January 2009

Background:

After a concussion, when symptoms have decreased substantially at rest, it is recommended that athletes begin light aerobic exercise before progressing to sport specific exercise. The British Columbia Concussion Rehabilitation Programme (BC-CRP) uses a standardized cognitive and exercise test protocol designed to indicate when an athlete should progress to sport-specific exercise after a concussion.

Objective:

To document the effects of exercise on symptom reporting in healthy, uninjured, male and female amateur athletes.

Design:

Quasi-experimental, pretest–post-test, nonequivalent groups design.

Methods:

Before the exercise protocol, 45 female and 30 male young amateur athletes completed computerized cognitive testing, symptom ratings and balance testing. The 15-minute cycle ergometry protocol, conducted at 90 revolutions/minute, was as follows: 0–2 minutes at 0 W tension, 2–5 minutes at 50 W, 5–8 minutes at 100 W, 8–11 minutes at 150 W and 11–14 minutes at 200 W tension followed by a 1-minute cooling-down period. After exercise, participants completed symptom ratings, balance testing and perceived exertion ratings. Self-reported symptoms were assessed using an abbreviated version of the Post-Concussion Scale.

Results:

Significant increases in self-reported balance problems, numbness and tingling were seen for both genders after aerobic exercise. For women, emotional symptoms such as irritability, sadness, nervousness and feeling more emotional decreased significantly after aerobic exercise. Headache also decreased in the women, but no significant change was seen in the men.

Conclusions:

Sex differences exist for symptom reporting after aerobic exercise. Both genders report increases in somatic symptoms, but only women report decreases in emotional symptoms. The concept of being “asymptomatic” after exercise should be reconsidered to include expected mild increases and decreases in certain symptoms.
Contribution of frequency-augmented inward Ca2+current to myocardial contractility
Authors: Parilak Leonard D. , Taylor David G. , Song Yejia , Burkart Thomas , Shryock John C. , Curtis Anne B. , Knot Harm J.
Published: January 2009

The sarcoplasmic reticular Ca2+pump (SERCA) is thought to be the primary determinant of heart rate-dependent increases in myocardial contractile [Ca2+]iand force (force–frequency relationship (FFR)), an important mechanism to increase cardiac output. This report demonstrates a rate-dependent role for inward Ca2+current (ICa) in the human and rat FFR. Human action potential plateau height increased linearly with contractility when heart rate increased in vivo, as measured by monophasic action potential catheter and echocardiography. Rat rate-dependent developed force and cytosolic [Ca2+]itransients were quantified in isolated left ventricular papillary muscles, and ICaand action potential duration in cardiomyocytes. ICaand SERCA measurements better reflected [Ca2+]iand force transients than SERCA activity alone. These data support a direct and (or) indirect contribution to myocardial contractility by ICaat heart rates from approximately 1 to 3–4 Hz (60 to 180–240 bpm) in tandem with SERCA to sustain the typical ‘bell shape’ of the FFR across species.
Chronic treatment with angiotensin AT1receptor antagonists reduced serum but not bone TGF-β1levels in ovariectomized rats
Authors: Li Yong-Qi , Ji Hui , Shen Yang , Ding Li-Ju , Zhuang Pei , Yang Yu-Lin , Huang Qiu-Ju
Published: January 2009

Approximately 50% of hypertensive patients are postmenopausal women; therefore, any antihypertensive therapy must not adversely affect bone loss in this population. Recently, however, concern has been raised that use of angiotensin AT1receptor antagonists may increase the tendency to develop postmenopausal osteoporosis by decreasing transforming growth factor-β1(TGF-β1), which has been implicated in bone mass maintenance. In the present study, we selected telmisartan and valsartan as representatives of angiotensin AT1receptor antagonists and used ovariectomized (OVX) rats as a model of human postmenopausal osteoporosis. After 3 months treatment with telmisartan (5 mg/kg daily) or valsartan (10 mg/kg daily), OVX rats showed no signs of adverse effects on bone mineral density of the lumbar vertebrae (L1–L5) or the total femur, nor did treatment affect serum levels of osteocalcin and osteoclast-derived tartrate-resistant acid phosphatase (TRACP-5b). Bone TGF-β1content remained unchanged, although treatment with telmisartan and valsartan significantly reduced serum TGF-β1levels (p < 0.05). In conclusion, chronic treatment with angiotensin AT1receptor antagonists reduced serum but not bone TGF-β1levels and did not accelerate ovariectomy-induced bone loss in rats.
Animal models of catheter-induced intimal hyperplasia in type 1 and type 2 diabetes and the effects of pharmacologic intervention
Authors: McNamara D.B. , Murthy S.N. , Fonseca A.N. , Desouza C.V. , Kadowitz P.J. , Fonseca V.A.
Published: January 2009

Diabetes is a complex disorder characterized by impaired insulin formation, release or action (insulin resistance), elevated blood glucose, and multiple long-term complications. It is a common endocrine disorder of humans and is associated with abnormalities of carbohydrate and lipid metabolism. There are two forms of diabetes, classified as type 1 and type 2. In type 1 diabetes, hyperglycemia is due to an absolute lack of insulin, whereas in type 2 diabetes, hyperglycemia is due to a relative lack of insulin and insulin resistance. More than 90% of people with diabetes have type 2 with varied degrees of insulin resistance. Insulin resistance is often associated with impaired insulin secretion, and hyperglycemia is a common feature in both types of diabetes, but failure to make a distinction between the types of diabetes in different animal models has led to confusion in the literature. This is particularly true in relation to cardiovascular disease in the presence of diabetes and especially the response to vascular injury, in which there are major differences between the two types of diabetes. Animal models do not completely mimic the clinical disease seen in humans. Animal models are at best analogies of the pathologic process they are designed to represent. The focus of this review is an analysis of intimal hyperplasia following catheter-induced vascular injury, including factors that may complicate comparisons between different animal models or between in vitro and in vivo studies. We examine the variables, pitfalls, and caveats that follow from the manner of induction of the injury and the diabetic state of the animal. The efficacy of selected antidiabetic drugs in inhibiting the development of the hyperplastic response is also discussed.
Sirt1 hyperexpression in SHR heart related to left ventricular hypertrophy
Authors: Li Ling , Zhao Lei , Yi-Ming Wuliya , Yu Yong-Sheng , Xia Chun-Yan , Duan Jun-Li , Su Ding-Feng
Published: January 2009

Sirt1 is a human homologue of the silent information regulator factor 2 (Sir2) and has an NAD+-dependent histone deacetylase activity. This protein is reported to have a pathogenetic role in muscle differentiation, diabetic nephropathy, and heart failure. In this study, we investigated the expression of sirt1 in spontaneously hypertensive rat (SHR) to obtain insight into the function of sirt1 in hypertensive cardiovascular hypertrophy. The gene and protein expression of sirt1 was increased in the heart in SHR compared with normotensive WKY rats. Sirt1 mRNA was not different in the aorta between SHR and WKY rats. Sirt1 mRNA expression in heart and aorta was not related to hemodynamic parameters in SHR. Hypertensive left ventricular hypertrophy was significantly and positively related to the expression of heart tissue sirt1 mRNA in SHR. Aortic hypertrophy, however, was not related to sirt1 mRNA in the aorta. The increased sirt1 protein expression was accompanied by severe cardiac hypertrophy in older SHR. These results suggest that the increase of sirt1 gene and protein expression in the heart was associated with cardiac hypertrophy.
Diethyl dithiocarbamic acid, a possible nuclear factor kappa B inhibitor, attenuates ischemic postconditioning-induced attenuation of cerebral ischemia–reperfusion injury in mice
Authors: Rehni Ashish K. , Bhateja Pradeep , Singh Nirmal
Published: January 2009

The present study was designed to pharmacologically investigate the possible role of nuclear factor kappa B (NF-κB) in the reversal of global cerebral injury induced by ischemia and reperfusion after ischemic postconditioning. Bilateral carotid artery occlusion for 17 min followed by reperfusion for 24 h was employed to produce ischemia- and reperfusion-induced cerebral injury in mice. Cerebral infarct size was measured by using triphenyltetrazolium chloride staining. Memory was evaluated using the Morris water maze test. The rotarod test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced a marked increase in cerebral infarct size, impairment of memory, and motor coordination. A set of 5 episodes of carotid artery occlusion for a period of 10 s and reperfusion of 10 s (ischemic postconditioning) significantly prevented ischemia–reperfusion-induced cerebral infarct size and behavioral deficits measured in terms of loss of memory and motor coordination. Diethyl dithiocarbamic acid sodium salt trihydrate (DDA) (100 mg/kg, i.p.), an inhibitor of NF-κB, given 30 min before ischemia attenuated the beneficial effects of ischemic postconditioning. It may be concluded that the beneficial effects of ischemic postconditioning on global cerebral ischemia- and reperfusion-induced cerebral injury and behavioral deficits may involve activation of the NF-κB-linked pathway.
Is there a role for T-type Ca2+channels in regulation of vasomotor tone in mesenteric arterioles?This article is part of a Special Issue on Information Transfer in the Microcirculation.
Authors: Jensen Lars Jørn , Holstein-Rathlou Niels-Henrik
Published: January 2009

The largest peripheral blood pressure drop occurs in terminal arterioles (<40 µm lumen diameter). L-type voltage-dependent Ca2+channels (VDCCs) are considered the primary pathway for Ca2+influx during physiologic activation of vascular smooth muscle cells (VSMC). Recent evidence suggests that T-type VDCCs are expressed in renal afferent and efferent arterioles, mesenteric arterioles, and skeletal muscle arterioles. T-type channels are small-conductance, low voltage-activated, fast-inactivating channels. Thus, their role in supplying Ca2+for contraction of VSMC has been disputed. However, T-type channels display non-inactivating window currents, which may play a role in sustained Ca2+entry. Here, we review the possible role of T-type channels in vasomotor tone regulation in rat mesenteric terminal arterioles. The CaV3.1 channel was immunolocalized in VSMC, whereas the CaV3.2 channel was predominantly expressed in endothelial cells. Voltage-dependent Ca2+entry was inhibited by the new specific T-type blockers R(–)-efonidipine and NNC 55-0396. The effect of NNC 55-0396 persisted in depolarized arterioles, suggesting an unusually high activation threshold of mesenteric T-type channels. T-type channels were not necessary for conduction of vasoconstriction, but appear to be important for local electromechanical coupling in VSMC. The first direct demonstration of endothelial T-type channels warrants new investigations of their role in vascular biology.
Role of spleen in integrated control of splanchnic vascular tone: physiology and pathophysiologyThis article is part of a Special Issue on Information Transfer in the Microcirculation.
Authors: Hamza Shereen M. , Kaufman Susan
Published: January 2009

Aside from its established immunologic and hematologic functions, the spleen also plays an important role in cardiovascular regulation. This occurs through changes in intrasplenic microvascular tone, as well as through splenic neurohormonal modulation of the renal and mesenteric vascular beds. Splenic regulation of blood volume occurs predominantly through fluid extravasation from the splenic circulation into lymphatic reservoirs; this is controlled by direct modulation of splenic pre- and postcapillary resistance by established physiologic agents such as atrial natriuretic peptide (ANP), nitric oxide (NO), and adrenomedullin (ADM). In addition to physiologic fluid regulation, splenic extravasation is a key factor in the inability to maintain adequate intravascular volume in septic shock. The spleen also controls renal microvascular tone through reflex activation of the splenic afferent and renal sympathetic nerves. This splenorenal reflex not only contributes to the physiologic regulation of blood pressure, but also contributes to the cardiovascular dysregulation associated with both septic shock and portal hypertension. In septic shock, the splenorenal reflex protectively limits splenic extravasation and potentially promotes renal sodium and water reabsorption and release of the vasoconstrictor angiotensin II; this function is eventually overwhelmed as shock progresses. In portal hypertension, on the other hand, the splenorenal reflex-mediated reduction in renal vascular conductance exacerbates sodium and water retention in the kidneys and may eventually contribute to renal dysfunction. Preliminary evidence suggests that the spleen also may play a role in the hemodynamic complications of portal hypertension via neurohormonal modulation of the mesenteric vascular bed. Lastly, the spleen itself may be a source of a vasoactive factor.
Current perspective on differential communication in small resistance arteriesThis article is part of a Special Issue on Information Transfer in the Microcirculation.
Authors: Tran Cam Ha T. , Welsh Donald G.
Published: January 2009

Blood flow is controlled by an integrated network of resistance arteries that are coupled in series and parallel with one another. To dramatically alter tissue perfusion as required during periods of high metabolic demand, arterial networks must dilate in a coordinated manner. Gap junctions facilitate arterial coordination by enabling electrical stimuli to conduct among endothelial and (or) smooth muscle cells. The goal of this review was to provide an introduction to the field of vascular communication, the process of intercellular conduction, and the manner in which key properties influence charge flow. After a brief historical introduction, we establish the idea that electrical stimuli conduct differentially among neighbouring endothelial and smooth muscle cells. Highlighting recent studies that have synergistically combined computational and experimental approaches, this perspective explores how specific structural, electrical, and gap junctional properties enable electrical phenomenon to conduct differentially. To close, the concept of differential communication is functionally integrated into a mechanistic understanding of blood flow control.
CHIRAL PARAMETRIZATION OF QCD VECTOR FIELD IN SU(3)
Authors: NOVOZHILOV VICTOR , NOVOZHILOV YURI
Published: January 2009

The chiral parametrization of gluons in SU(3) QCD is proposed extending an approach developed earlier for SU(2) case. A color chiral field is introduced, gluons are chirally rotated, and vector component of rotated gluons is defined on condition that no new color variables appeared with the chiral field. This condition associates such a vector component with SU(3)/U(2) coset plus a U(2) field. The topological action in SU(3) QCD is derived. It is expressed in terms of axial vector component of rotated gluons. The vector field in CP2 sector is studied in new variables of chiral parametrization.
CORRELATION OF ENERGY DENSITY IN DECONFINING SU(2) YANG–MILLS THERMODYNAMICS
Authors: KELLER JOCHEN , HOFMANN RALF , GIACOSA FRANCESCO
Published: January 2009

We compute the two-point correlation of the energy density for the massless mode in deconfining SU(2) Yang–Mills thermodynamics and point towards a possible application for the physics of cold, dilute, and stable clouds of atomic hydrogen within the Milky Way.
CENTRALITY, SYSTEM SIZE AND ENERGY DEPENDENCE OF CHARGED PARTICLE PSEUDORAPIDITY DISTRIBUTION
Authors: WEI DE-MING , SHAO FENG-LAN , SONG JUN , WANG YUN-FEI
Published: January 2009

Utilizing the three-fireball picture within the quark combination model, we study systematically the charged particle pseudorapidity distributions in both Au + Au and Cu + Cu collision systems as a function of collision centrality and energy, [Formula: see text], 62.4, 130 and 200 GeV, in the full pseudorapidity range. We find that: (i) the contribution from leading particles to dN ch /dη distributions increases with the decrease of the collision centrality and energy respectively; (ii) the number of leading particles is almost independent of the collision energy, but it does depend on the nucleon participants N part ; (iii) if Cu + Cu and Au + Au collisions at the same collision energy are selected to have the same N part , the resulting charged particle dN/dη distributions are nearly identical, in both the midrapidity particle density and the width of the distribution; this is true for both 62.4 GeV and 200 GeV data; (iv) the limiting fragmentation phenomenon is reproduced. We predict the total multiplicity and pseudorapidity distribution for the charged particles in Pb + Pb collisions at [Formula: see text]. Finally, we give a qualitative analysis of N ch /〈N part /2〉 and dN ch /dη/〈N part /2〉|η≈0 as a function of [Formula: see text] and N part from the RHIC to the LHC.
HYBRID STATES FROM CONSTITUENT GLUE MODEL
Authors: IDDIR FARIDA , SEMLALA LAHOUARI
Published: January 2009

The hybrid meson is one of the most interesting new hadron species beyond the naive quark model. It acquire great attention both from the theoretical and experimental efforts. Many good candidates have been claimed to be observed, but there is no absolute confirmation about the existence of hybrid mesons. In the present work we propose new calculations of the masses and decay widths of the hybrid mesons in the context of constituent gluon model.
PROSPECTS FOR HIGGS BOSON SEARCHES AT THE LHC
Authors: JAKOBS KARL , SCHUMACHER MARKUS
Published: January 2009

The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of experiments at the CERN Large Hadron Collider (LHC). The experiments ATLAS and CMS have been designed to be able to discover a Standard Model Higgs boson over the full mass range as well as Higgs bosons in extended models. In this paper, the prospects for Higgs boson searches at the LHC are reviewed. In addition, the potential for the measurement of Higgs boson parameters is discussed.
GENERATION OF MULTIPHOTON POLARIZATION-ENTANGLED CLUSTER STATES AND THE CORRESPONDING OPEN-DESTINATION TELEPORTATION
Authors: CHANG DI , HUANG YONG-CHANG
Published: January 2009

We propose a method to generate multiphoton polarization-entangled cluster states of any number photons by using the fusion operations of two-photon cluster states and a kind of local operation, and then analyze the process of open-destination teleportation of a single photon state using the generated states. Apart from theoretical deductions, we also give the experimentally schematic diagram, which requires only BBOs, Polarization Beam Splitters, half-wave plates, single photon resources as well as some other linear optical elements. The equipment and techniques used here are all feasible under current technology.
THERMAL HYSTERESIS IN RESISTIVITY AND MAGNETIZATION OF PrCa(Sr)MnO
Authors: MOLLAH S.
Published: January 2009

Thermal hysteresis in resistivity and magnetization of Pr 0.65 Ca 0.35-x Sr x MnO 3(x = 0–0.35) manganites has been systematically studied to establish the interplay of their charge and spin-ordering. The increasing Sr concentration (x) transforms the charge-ordered (CO)/antiferromagnetic (AFM) insulating system (for x = 0) into a mixed-phased one (for x = 0.1) with sharp metal–insulator (MI) transition and finally leads to a ferromagnetic (FM) metallic (for x = 0.35) system. It has been found that the interplay of charge and spin-ordering is higher in mixed-phased state and the thermal hysteresis loop area is bigger. It increases with the increase of sharpness of MI transition. Interplay of charge and spin-ordering decreases with the increase of either CO/AFM insulating or FM metallic phase and is almost absent in completely CO/AFM insulating (with x = 0) or FM metallic (with x = 0.35) states bringing about zero thermal hysteresis loop.
THE MULTISCALE MODEL COMBINING ELASTIC THEORY WITH AB INITIO CALCULATIONS FOR METAL–CERAMIC INTERFACES
Authors: ZHANG YING , YAO YUGUI
Published: January 2009

The generalized two-dimensional Peierls–Nabarro (PN) model7 for studying interfaces is developed further, where an exact generalized stacking fault energy γ-surface obtained from ab initio calculations acts as an input function for the generalized PN model. Using the multiscale modeling techniques, which combines elastic theory with ab initio calculations, the structure and energy of the Al/MgO (100) interface are studied, and the effectiveness of this method is demonstrated.
OPERATOR JOSEPHSON EQUATION FOR A JOSEPHSON JUNCTION CONNECTED INTO A MESOSCOPIC LC CIRCUIT
Authors: WANG JI-SUO , LIANG BAO-LONG , FAN HONG-YI
Published: January 2009

We find that when a single Josephson junction is inserted into a mesoscopic LC circuit, the operator Josephson equation is modified accompanying with the modification of Farady equation describing the inductance. By virtue of the entangled state representation and using the appropriate phase operator in bosonic form we derive the modified equations.
THE NONLINEARIZATION OF A (2+1)-DIMENSIONAL SOLITON EQUATION
Authors: LIU QIANG , DU DIAN-LOU
Published: January 2009

Based on a 2 × 2 eigenvalue problem, a new (2+1)-dimensional soliton equation is proposed. Moreover, we obtain a finite-dimensional Hamiltonian system. Then we verify it is completely integrable in the Liouville sense. In the end, we introduce a set of Hk polynomial integrable, by which we can separate the solition equation into three compantiable Hamiltonian systems of ordinary differential equation.
STRUCTURE AND TRANSPORT PROPERTIES OF Pr1-xSr1+xCoO4
Authors: LI M. , HUANG S. L. , LV Z. M. , ZHANG J. L. , WU H. Y. , WANG X. M. , PANG Z. Q. , RUAN K. Q.
Published: January 2009

Powder X-ray diffraction, Raman scattering and infrared spectra at different doping (x = 0 ~ 0.5) on polycrystalline Pr 1-x Sr 1+x CoO 4 were performed. With increasing x, the shift of Raman scattering spectra is due to the enhancement of electron–phonon interaction along the c-axis. The contrary variation of infrared in wavenumber comes from the weakening electron–phonon interactions in the ab plane. There is a dramatic variation in resistivity as x increases, which is also caused by increasing carrier concentration and is related to the band shift. For Pr 1-x Sr 1+x CoO 4, both A1g bands shift to low frequency and reach a minimum when x = 0.3 and the resistivity of Pr 0.7 Sr 1.3 CoO 4 is the smallest at room temperature.
OPTICAL NONLINEARITY OF CdSe AND CdSe-C60 QUANTUM DOT
Authors: SONG HAO , ZHAI YUE-YING , ZHOU ZHANG-KAI , HAO ZHONG-HUA , ZHOU LI
Published: January 2009

The third-order optical nonlinear properties of CdSe quantum dots (QDs) and CdSe - C 60 QDs are investigated by Z-scan technique with picosecond pulses at the wavelength of 800 nm. The value of the nonlinear absorption coefficient β of CdSe - C 60 QDs is measured to be 2.9 cm/GW, which is about two times larger than that of CdSe QDs. The nonlinear refraction index γ of CdSe - C 60 QDs is -2.8 × 10-3 cm 2/ GW , which is about seven times larger than that of CdSe QDs. Presence of C 60 contributes to the larger optical nonlinearity of CdSe - C 60 QDs comparing with CdSe QDs.
SOME EXPANDING SEMI-DIRECT SUMS OF LIE ALGEBRA $\bar{G}$ AND ITS APPLICATION
Authors: CHANG HUI , CHANG SHUANGLING , ZHANG YU
Published: January 2009

Based on the fundamental special Lie algebra [Formula: see text], some semi-direct sums are presented. Then, a new semi-direct sum Lie algebra [Formula: see text] is constructed. The method presented in this paper can be used to obtain other higher-dimensional Lie algebra. Making use of the above Lie algebra, three integrable couplings of the new Bargmann type lattice hierarchy are obtained.
INFLUENCES OF SPRING CONSTANTS AND GENERATIONS ON THE PHONON SPECTRA OF FIBONACCI CHAIN
Authors: HU XUBO , YANG XIANGBO
Published: January 2009

In the frame work of the nearest-neighbor harmonic spring model, we calculate the phonon spectra by means of the transfer matrix method and investigate the influences of the spring constants, the periodicity, the degree of defect for a periodic chain and the length of a chain on the phonon spectra of Fibonacci chain. It is found that for a certain generation chain the range of the phonon spectra enlarges from the low- to high-frequency zone with the increment of the parameter λ, and when the structure of a chain is certain, the spectra range decreases and more and more phonon states with higher frequencies disappear with the increment of generation. Consequently, when the chain tends to be infinite, there only exist very few phonon states with low-frequency. On the other hand, for a certain Fibonacci chain, phonon states with high-frequency can be formed only when λ is larger than the corresponding critical value.
REGION SIMILARITY RELATIONSHIP BETWEEN WATERSHED AND PENALIZED FUZZY HOPFIELD NEURAL NETWORK ALGORITHMS FOR BRAIN IMAGE SEGMENTATION
Authors: KUO WEN-FENG , LIN CHI-YUAN , SUN YUNG-NIEN
Published: January 2009

A robust image segmentation method that combines the watershed segmentation and penalized fuzzy Hopfield neural network (PFHNN) algorithms to minimize undesirable over-segmentation is described in this paper. This method incorporates spatial graph representation derived from the watershed segmented regions and cluster analysis information obtained from the PFHNN algorithm to achieve efficient image segmentation. The proposed scheme employs the Markov random field (MRF) model on the region adjacency graph (RAG) to improve the quality of watershed segmentation. Here, the fusion criterion is according to the correlation coefficient, which uses inter-region similarities to determine the merging of regions. Analysis of the performance of the proposed technique is presented through quantitative and qualitative validation experiments on benchmark images, and significant and promising segmentation results are presented using brain phantom simulated data.
FUSING GLOBAL AND LOCAL COMPLETE LINEAR DISCRIMINANT FEATURES BY FUZZY INTEGRAL FOR FACE RECOGNITION
Authors: ZHANG CHENGYUAN , RUAN QIUQI , JIN YI
Published: January 2009

Face recognition becomes very difficult in a complex environment, and the combination of multiple classifiers is a good solution to this problem. A novel face recognition algorithm GLCFDA-FI is proposed in this paper, which fuses the complementary information extracted by complete linear discriminant analysis from the global and local features of a face to improve the performance. The Choquet fuzzy integral is used as the fusing tool due to its suitable properties for information aggregation. Experiments are carried out on the CAS-PEAL-R1 database, the Harvard database and the FERET database to demonstrate the effectiveness of the proposed method. Results also indicate that the proposed method GLCFDA-FI outperforms five other commonly used algorithms — namely, Fisherfaces, null space-based linear discriminant analysis (NLDA), cascaded-LDA, kernel-Fisher discriminant analysis (KFDA), and null-space based KFDA (NKFDA).
RECOGNIZING OVERLAPPED HUMAN ACTIVITIES FROM A SEQUENCE OF PRIMITIVE ACTIONS VIA DELETED INTERPOLATION
Authors: KITANI KRIS M. , SATO YOICHI , SUGIMOTO AKIHIRO
Published: January 2009

The high-level recognition of human activity requires a priori hierarchical domain knowledge as well as a means of reasoning based on that knowledge. Based on insights from perceptual psychology, the problem of human action recognition is approached on the understanding that activities are hierarchical, temporally constrained and at times temporally overlapped. A hierarchical Bayesian network (HBN) based on a stochastic context-free grammar (SCFG) is implemented to address the hierarchical nature of human activity recognition. Then it is shown how the HBN is applied to different substrings in a sequence of primitive action symbols via deleted interpolation (DI) to recognize temporally overlapped activities. Results from the analysis of action sequences based on video surveillance data show the validity of the approach.
INTEGRATION OF n-GRAM LANGUAGE MODELS IN MULTIPLE CLASSIFIER SYSTEMS FOR OFFLINE HANDWRITTEN TEXT LINE RECOGNITION
Authors: BERTOLAMI ROMAN , BUNKE HORST
Published: January 2009

Current multiple classifier systems for unconstrained handwritten text recognition do not provide a straightforward way to utilize language model information. In this paper, we describe a generic method to integrate a statistical n-gram language model into the combination of multiple offline handwritten text line recognizers. The proposed method first builds a word transition network and then rescores this network with an n-gram language model. Experimental evaluation conducted on a large dataset of offline handwritten text lines shows that the proposed approach improves the recognition accuracy over a reference system as well as over the original combination method that does not include a language model.
Statistical Analysis and Process Variation-Aware Routing and Skew Assignment for FPGAs
Authors: Sivaswamy Satish , Bazargan Kia
Published: January 2009

With constant scaling of process technologies, chip design is becoming increasingly difficult due to process variations. The FPGA community has only recently started focusing on the effects of variations. In this work we present a statistical analysis to compare the effects of variations on designs mapped to FPGAs and ASICs. We also present CAD and architecture techniques to mitigate the impact of variations. First we present a variation-aware router that optimizes statistical criticality. We then propose a modification to the clock network to deliver programmable skews to different flip-flops. Finally, we combine the two techniques and the result is a 9x reduction in yield loss that translates to a 12% improvement in timing yield. When the desired timing yield is set to 99%, our combined statistical routing and skew assignment technique results in a delay improvement of about 10% over a purely deterministic approach.
A Synthesizable Datapath-Oriented Embedded FPGA Fabric for Silicon Debug Applications
Authors: Wilton Steven J.E. , Ho Chun Hok , Quinton Bradley , Leong Philip H.W. , Luk Wayne
Published: January 2009

We present an architecture for a synthesizable datapath-oriented FPGA core that can be used to provide post-fabrication flexibility to an SoC. Our architecture is optimized for bus-based operations and employs a directional routing architecture, which allows it to be synthesized using standard ASIC design tools and flows. The primary motivation for this architecture is to provide an efficient mechanism to support on-chip debugging. The fabric can also be used to implement other datapath-oriented circuits such as those needed in signal processing and computation-intensive applications. We evaluate our architecture using a set of benchmark circuits and compare it to previous fabrics in terms of area, speed, and power.
Evaluation of American Sign Language Generation by Native ASL Signers
Authors: Huenerfauth Matt , Zhao Liming , Gu Erdan , Allbeck Jan
Published: January 2009

There are many important factors in the design of evaluation studies for systems that generate animations of American Sign Language (ASL) sentences, and techniques for evaluating natural language generation of written texts are not easily adapted to ASL. When conducting user-based evaluations, several cultural and linguistic characteristics of members of the American Deaf community must be taken into account so as to ensure the accuracy of evaluations involving these users. This article describes an implementation and user-based evaluation (by native ASL signers) of a prototype ASL natural language generation system that produces sentences containing classifier predicates, which are frequent and complex spatial phenomena that previous ASL generators have not produced. Native signers preferred the system's output to Signed English animations -- scoring it higher in grammaticality, understandability, and naturalness of movement. They were also more successful at a comprehension task after viewing the system's classifier predicate animations.
Goal Crossing with Mice and Trackballs for People with Motor Impairments
Authors: Wobbrock Jacob O. , Gajos Krzysztof Z.
Published: January 2009

Prior research shows that people with motor impairments face considerable challenges when using conventional mice and trackballs. One challenge is positioning the mouse cursor within confined target areas; another is executing a precise click without slipping. These problems can make mouse pointing in graphical user interfaces very difficult for some people. This article explores goal crossing as an alternative strategy for more accessible target acquisition. In goal crossing, targets are boundaries that are simply crossed by the mouse cursor. Thus, goal crossing avoids the two aforementioned problems. To date, however, researchers have not examined the feasibility of goal crossing for people with motor difficulties. We therefore present a study comparing area pointing and goal crossing. Our performance results indicate that although Fitts' throughput for able-bodied users is higher for area pointing than for goal crossing (4.72 vs. 3.61 bits/s), the opposite is true for users with motor impairments (2.34 vs. 2.88 bits/s). However, error rates are higher for goal crossing than for area pointing under a strict definition of crossing errors (6.23% vs. 1.94%). We also present path analyses and an examination of submovement velocity, acceleration, and jerk (the change in acceleration over time). These results show marked differences between crossing and pointing and almost categorically favor crossing. An important finding is that crossing reduces jerk for both participant groups, indicating more fluid, stable motion. To help realize the potential of goal crossing for computer access, we offer design concepts for crossing widgets that address the occlusion problem, which occurs when one crossing goal obscures another in persistent mouse-cursor interfaces. This work provides the motivation and initial steps for further exploration of goal crossing on the desktop, and may help researchers and designers to radically reshape user interfaces to provide accessible goal crossing, thereby lowering barriers to access.
The Field Evaluation of a Mobile Digital Image Communication Application Designed for People with Aphasia
Authors: Allen Meghan , McGrenere Joanna , Purves Barbara
Published: January 2009

PhotoTalk is an application for a mobile device that allows people with aphasia to capture and manage digital photographs to support face-to-face communication. Unlike any other augmentative and alternative communication device for people with aphasia, PhotoTalk focuses solely on image capture and organization and is designed to be used independently. Our project used a streamlined process with three phases: (1) a rapid participatory design and development phase with two speech-language pathologists acting as representative users, (2) an informal usability study with five aphasic participants, which caught usability problems and provided preliminary feedback on the usefulness of PhotoTalk, and (3) a one-month field evaluation with two aphasic participants followed by a one-month secondary field evaluation with one aphasic participant, which showed that they all used it regularly and relatively independently, although not always for its intended communicative purpose. Our field evaluations demonstrated PhotoTalk's promise in terms of its usability and usefulness ineveryday communication.
Sibylle, An Assistive Communication System Adapting to the Context and Its User
Authors: Wandmacher Tonio , Antoine Jean-Yves , Poirier Franck , Départe Jean-Paul
Published: January 2009

In this article, we describe the latest version of Sibylle, an AAC system that permits persons who have severe physical disabilities to enter text with any computer application, as well as to compose messages to be read out through speech synthesis. The system consists of a virtual keyboard comprising a set of keypads that allow for the entering of characters or full words by a single-switch selection process. It also includes a sophisticated word prediction component which dynamically calculates the most appropriate words for a given context. This component is auto-adaptive, that is, it learns with every text the user enters. It thus adapts its predictions to the user's language and the current topic of communication as well. So far, the system works for French, German and English. Earlier versions of Sibylle have been used since 2001 in a rehabilitation center (Kerpape, France).
Sampled 3D models for CH applications
Authors: Cignoni Paolo , Scopigno Roberto
Published: January 2009

Any application of three-dimensional computer graphics in the Cultural Heritage (CH) field requires availability of a digital model of the artifact(s) treated. Detailed and accurate digital 3D models can be produced with 3D scanning devices, which allow conversion of reality into digital form in a cost and time-effective manner. We present the capabilities of this technology and the main issues which are preventing its wider use in contemporary applications, highlighting some open problems and a few promising new approaches for 3D model construction. We also briefly review some CH applications which could boost the diffusion and evolution of 3D scanning technology.
Access to recorded interviews
Authors: Jong Franciska De , Oard Douglas W. , Heeren Willemijn , Ordelman Roeland
Published: January 2009

Recorded interviews form a rich basis for scholarly inquiry. Examples include oral histories, community memory projects, and interviews conducted for broadcast media. Emerging technologies offer the potential to radically transform the way in which recorded interviews are made accessible, but this vision will demand substantial investments from a broad range of research communities. This article reviews the present state of practice for making recorded interviews available and the state-of-the-art for key component technologies. A large number of important research issues are identified, and from that set of issues, a coherent research agenda is proposed.
Research between natural and cultural history information
Authors: Lampe Karl-Heinz , Riede Klaus , Doerr Martin
Published: January 2009

This article describes an approach to transdisciplinary information integration employing a core ontology. Information is modeled here with an ontology based on the CIDOC-Conceptual Reference Model (ISO 21127). When instantiated with some realistic examples taken from the field of biodiversity (collecting, determination, type creation, expedition, and observation events), the formal specification of semantic concepts makes scientific activities commonly understandable. Ontologies not only allow one to describe the results of scientific activities, such as a description of a biological species, but they can help to clarify the path by which the goal was reached. In particular, they provide a high-level uniform representation of transdisciplinary research activities and results. Ontologies as knowledge representation tools will therefore have strong impact on methodological questions and research strategies for different domains such as biology, archaeology, art history, and socio-economy. They can be regarded as semantic glue between and within scientific and scholarly domains as demonstrated in a series of examples. Following this approach, some requirements for research and development of integrated IT environments between memory instutions are derived.
The preservation, emulation, migration, and virtualization of live electronics for performing arts
Authors: Bonardi Alain , Barthélemy Jérome
Published: January 2009

Centers for electronic music creation now face strong difficulties to reperform important works considered as belonging to their repertoire. They realize the fragility of works based on electronic modules, subject to technology changes. Sustainability can be achieved in four different ways that are examined in this article: preservation, emulation, migration and virtualization. We discuss these issues, showing the first steps towards solutions at Ircam in the framework of the European project Caspar.