bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethnic group, acculturation, and psychiatric problems in young immigrants
Authors: Oppedal Brit , Røysamb Espen , Heyerdahl Sonja
Published: May 2005

Background:  The goal of this study was to investigate the effects of ethnic origin and acculturation factors on psychiatric problems among immigrant adolescents. One aim was to examine variations in psychiatric problems according to gender and immigrant generation level. Another aim was to explore ethnic group differences in psychiatric problems and acculturation risk and protective factors. Finally, we examined the potential mediating effect of acculturation in the relationship between ethnic origin and psychiatric symptoms.

Method:  Questionnaire data were collected from 1275 immigrant 10th graders with 11 different ethnic origins. Psychiatric problems were measured by the Strength and Difficulty Questionnaire. Acculturation risk factors involved perceived discrimination and ethnic identity crisis. Protective factors were family values, host and ethnic culture competence.

Results:  First‐generation girls and second‐generation boys were identified as particularly vulnerable to psychiatric problems. There was significant variation in psychiatric problems and acculturation between ethnic groups. There was substantial ethnic group‐level correlation between emotional and conduct problems, and between discrimination and peer problems. Otherwise, a differentiated pattern of high‐scoring ethnic groups emerged across the various symptom and acculturation indices. ANOVAs yielded unique effects on each symptom category of both ethnic group and the acculturation risk and protective factors, undermining the notion of a mediating effect of acculturation.

Conclusions:  There is a complex pattern of adaptation in cultural context and idiosyncratic relationships between distinct psychiatric symptom groups and socio‐cultural factors. Information about the differentiated vulnerability of gender, generation, and ethnic groups to psychiatric morbidity is important to identify groups at special risk, and to produce interventions that are tailored to their needs. Future studies should examine how cultural factors contribute both to resilience and to an increased vulnerability to psychiatric problems.
Annotation: Velo‐cardio‐facial syndrome
Authors: Murphy K.C.
Published: May 2005

Background:  Velo‐cardio‐facial syndrome (VCFS), the most frequent known interstitial deletion identified in man, is associated with chromosomal microdeletions in the q11 band of chromosome 22. Individuals with VCFS are reported to have a characteristic behavioural phenotype with high rates of behavioural, psychiatric, neuropsychological and linguistic disorders.

Methods:  A selective literature review was undertaken.

Results:  Children and adults with VCFS have high rates of behavioural, psychiatric and communication disorders. While VCFS children have high rates of ADHD, anxiety and affective disorders, adults have high rates of psychotic disorders, particularly schizophrenia. In addition, the presence of a chromosome 22q11 deletion is associated with specific neuropsychological and neuroanatomical abnormalities.

Conclusions:  People with VCFS have a characteristic behavioural phenotype with high rates of behavioural, psychiatric, neuropsychological and communication disorders. Early diagnosis and treatment within a multidisciplinary framework is of paramount importance for VCFS individuals as this will have a major effect in determining the long‐term outcome in affected individuals. Longitudinal studies of VCFS children are currently under way to identify precursor symptoms and areas of dysfunction which precede the later development of major psychiatric disorder. Identification of such prodromal features in VCFS may have enormous implications for the clinical management of major psychiatric disorder in VCFS and in the wider population.
No effect of MMR withdrawal on the incidence of autism: a total population study
Authors: Honda Hideo , Shimizu Yasuo , Rutter Michael
Published: May 2005

Background:  A causal relationship between the measles, mumps, and rubella (MMR) vaccine and occurrence of autism spectrum disorders (ASD) has been claimed, based on an increase in ASD in the USA and the UK after introduction of the MMR vaccine. However, the possibility that this increase is coincidental has not been eliminated. The unique circumstances of a Japanese MMR vaccination program provide an opportunity for comparison of ASD incidence before and after termination of the program.

Methods:  This study examined cumulative incidence of ASD up to age seven for children born from 1988 to 1996 in Kohoku Ward (population approximately 300,000), Yokohama, Japan. ASD cases included all cases of pervasive developmental disorders according to ICD‐10 guidelines.

Results:  The MMR vaccination rate in the city of Yokohama declined significantly in the birth cohorts of years 1988 through 1992, and not a single vaccination was administered in 1993 or thereafter. In contrast, cumulative incidence of ASD up to age seven increased significantly in the birth cohorts of years 1988 through 1996 and most notably rose dramatically beginning with the birth cohort of 1993.

Conclusions:  The significance of this finding is that MMR vaccination is most unlikely to be a main cause of ASD, that it cannot explain the rise over time in the incidence of ASD, and that withdrawal of MMR in countries where it is still being used cannot be expected to lead to a reduction in the incidence of ASD.
Long‐term results and survival rate of implants treated with guided bone regeneration: a 5‐year case series prospective study
Authors: Blanco Juan , Alonso Angel , Sanz Mariano
Published: May 2005

Abstract: One of the key factors for attaining osseointegration is the presence of an adequate osseous volume. In patients with inadequate osseous width or height, a bone augmentation using the guided bone regeneration (GBR) concept may be applied either with a simultaneous or a staged approach. The aim of this multicenter prospective case series study was to evaluate the efficacy and predictability of the GBR technique (simultaneous approach) in patients with peri‐implant osseous defects, both dehiscences and fenestrations. Results 5 years post‐treatment (survival rates and marginal bone level) were assessed. A total of 19 consecutive patients with 26 peri‐implant osseous defects (20 dehiscences and six fenestrations) were treated during the period from September 1992 to June 1993 with a simultaneous GBR approach using non‐resorbable membranes combined with autogenous bone grafts or decalcified freeze‐dried bone allograft. The mean osseous augmentation was 94.8%. Marginal bone levels at re‐entry and 5 years after surgery were calculated from standardized periapical radiographs. One implant was lost 3 months after loading. Thus, the cumulative survival rate was 96.1% after 5 years. The mean marginal bone level after 5 years was 2.03 mm (SD=±0.5), without a difference between mesial and distal sites. This study demonstrates that implants with peri‐implant defects that are treated with GBR had similar survival rates and crestal bone levels compared with implants in native bone.
Treatment of peri‐implantitis by the Vector® system
Authors: Karring Eva S. , Stavropoulos Andreas , Ellegaard Birgit , Karring Thorkild
Published: May 2005

Aim: To compare the effectiveness of treatment of peri‐implantitis with a novel ultrasonic device, the Vector® system, with that of subgingival debridement with carbon fiber curettes.

Material and methods: The study, comprising 11 patients with at least two screw type implants with bleeding on probing (BOP), probing pocket depth (PPD)≥5 mm, and at least 1.5 mm radiographic bone loss and exposed implant threads, was carried out as a single blind randomized clinical trial. At baseline one randomly chosen implant in each patient was treated by the Vector® system (test) while the other implant (control) was treated by submucosal debridement with a carbon fiber curette. After 3 months, the same treatments were repeated. Plaque, BOP, and PPD were recorded on all implant surfaces at baseline, and after 3 and 6 months. Bone levels were recorded on radiographs taken prior to the start of the study, and after 6 months.

Results: Oral hygiene around both test and control implants was improved at 3 and 6 months compared with baseline. At 6 months, four of the Vector®‐treated sites, and only one site treated with curettes, had stopped to bleed. In neither the test nor the control group, were there any differences between baseline and 6 months regarding PPD and bone levels.

Conclusion: Although there was a greater reduction in the number of sites with BOP following treatment with the Vector® system than following instrumentation with carbon fiber curettes, there was no significant difference between the two methods.
Analysis of the crown fractures and crown‐root fractures due to dental trauma assisted by the Integrated Clinic from 1992 to 2002
Authors: Castro José Carlos Monteiro , Poi Wilson Roberto , Manfrin Thais Mara , Zina Lívia Guimarães
Published: May 2005

Abstract –  The purpose of this study was to analyze crown fractures and crown‐root fractures due to dentoalveolar trauma, treated in the Integrated Clinic comprehensive dental care at Araçatuba School of Dentistry (UNESP), from January 1992 to July 2002. The data were obtained from files of trauma cases. On the analysis period, 293 patients had crown fractures or crown‐root fractures, in 605 teeth. Sixty‐nine percent were males and 31% were females. Adolescents between 11 and 18 years old were the most prevalent group (41.6%) and the maxillary arch was the most commonly traumatized (83%). The most commonly affected tooth was the maxillary central incisor (58.3%). The most frequent causes were falls from bicycles (30.8%). It was concluded that the reality of the local service is similar to the published data.
Orthodontic movement of a horizontally fractured tooth: a case report
Authors: Erdemir Ali , Ungor Mete , Erdemir Ebru Olgun
Published: May 2005

Abstract –  Intra‐alveolar root fractures are relatively uncommon, and sometimes may be healed without treatment. Diagnosis of intra‐alveolar root fracture is frequently made by exclusion of clinical signs of other traumatic injury, and by radiographic examination with films taken at different tube angulations. This case report presents a horizontal root fractured tooth that was healed satisfactory without treatment and moved orthodontically after prolonged time from trauma.
Forced eruption after crown/root fracture with a simple and aesthetic method using the fractured crown
Authors: Emerich‐Poplatek Katarzyna , Sawicki Leszek , Bodal Maciej , Adamowicz‐Klepalska Barbara
Published: May 2005

Abstract –  Forced eruption offers a method of treatment of teeth fractured close to the alveolar crest. We introduce a modification of this common technique. The fractured fragment of a patient's crown is bonded to the adjacent teeth and used as anchorage, permiting the root extrusion while offering acceptable aesthetics. The bonded crown does not impede the eruption of the root so that the frequent occlusal adjustment of other methods is not required. The final result is acceptable and a low cost alternative to common techniques.
Structural resistance in immature teeth using root reinforcements in vitro
Authors: Carvalho C. A. T. , Valera M. C. , Oliveira L. D. , Camargo C. H. R.
Published: May 2005

Abstract –  The purpose of this study was to evaluate in vitro the efficacy of root reinforcements by light‐cured composite resin or zirconium fiber post in simulated immature non‐vital teeth. Fifty‐six bovine incisors teeth were used for this study. The crown of each tooth was removed in the medium third to obtain a standard length of 30 mm. The specimens were divided into four groups (n = 14): G1) the root canals were instrumented and enlarged to simulate immature non‐vital teeth and were reinforced with a light‐cured composite resin using a translucent curing post (Luminex system); (G2) the specimens were instrumented, enlarged and they received root reinforcement with zirconium fiber post; G3 (positive control): they received similar treatment to the G1 and G2 groups, but did not receive root reinforcement; G4 (negative control): the roots were not weakened and did not receive reinforcement. Every tooth was submitted to compressive force using an Instron testing machine with an angle of 45° at a speed of 1 mm min−1 until the fracture. The results showed a markedly increased resistance to fracture in the G1 and G2 (122.38 and 122.08 kgf, respectively). Among the results of G1 and G2 there was not any significant difference (P > 0.05) but they were significantly different from the control groups (P < 0.05). The conclusion is that the use of root reinforcements with zirconiun fiber post or composite resin can increase significantly the structural resistance of the weakened teeth, decreasing the risk of the fracture.
Active Control of Tip Clearance Flow in Axial Compressors
Authors: Bae Jin Woo , Breuer Kenneth S. , Tan Choon S.
Published: May 2005

Control of compressor tip clearance flows is explored in a linear cascade using three types of fluidic actuators; normal synthetic jet (NSJ; unsteady jet normal to the mean flow with zero net mass flux), directed synthetic jet (DSJ; injection roughly aligned with the mean flow), and steady directed jet (SDJ), mounted on the casing wall. The effectiveness of each active control technique is determined in terms of its ability to achieve: (1) reduction of tip leakage flow rate, (2) mixing enhancement between tip leakage and core flow, and (3) increase in streamwise momentum of the flow in the endwall region. The measurements show that the NSJ provides mixing enhancement only, or both mixing enhancement and leakage flow reduction, depending on its pitchwise location. The DSJ and SDJ actuators provide streamwise momentum enhancement with a consequent reduction of clearance-related blockage. The blockage reduction associated with the use of NSJ is sensitive to actuator frequency, whereas that with the use of DSJ is not. For a given actuation amplitude, DSJ and SDJ are about twice as effective as NSJ in reducing clearance-related blockage. Further the DSJ and SDJ can eliminate clearance-related blockage with a time-averaged momentum flux roughly 16% of the momentum flux of the leakage flow. However, achieving an overall gain in efficiency appears to be hard; the decrease in loss is only about 30% of the expended flow power from the present SDJ actuator. Guidelines for improving the efficiency of the directed jet actuation are presented.
Numerical Study of Unsteady Flow in a Centrifugal Pump
Authors: Majidi Kitano
Published: May 2005

Computational fluid dynamics (CFD) analysis has been used to solve the unsteady three-dimensional viscous flow in the entire impeller and volute casing of a centrifugal pump. The results of the calculations are used to predict the impeller/volute interaction and to obtain the unsteady pressure distribution in the impeller and volute casing. The calculated unsteady pressure distribution is used to determine the unsteady blade loading. The calculations at the design point and at two off-design points are carried out with a multiple frame of reference and a sliding mesh technique is applied to consider the impeller/volute interaction. The results obtained show that the flow in the impeller and volute casing is periodically unsteady and confirm the circumferential distortion of the pressure distribution at the impeller outlet and in the volute casing. Due to the interaction between impeller blades and the tongue of the volute casing the flow is characterized by pressure fluctuations, which are strong at the impeller outlet and in the vicinity of the tongue. These pressure fluctuations are died away in the casing as the advancement angle increases. These reduced pressure fluctuations are spread to the discharge nozzle; the pressure fluctuations are also reflected to the impeller inlet and they affect the mass flow rate through the blade passages.
Parametric Effects on Heat Transfer of Impingement on Dimpled Surface
Authors: Kanokjaruvijit Koonlaya , Martinez-Botas Ricardo F.
Published: May 2005

Jet impingement on a dimpled surface is investigated experimentally for Reynolds numbers in the range 5000–11500, and jet-to-plate spacing from 1 to 12 jet-diameters. These include spatially resolved local Nusselt numbers with impingement both on the dimpled itself and on the flat portion between dimples. Two dimple geometries are considered: hemispherical dimples and double or cusp elliptical dimples. All experiments were carried under maximum crossflow that is the spent air exits along one way. At the narrow jet-to-plate spacing such as H/Dj=2, a vigorous recirculation occurred, which prevented the dimpled plate to enhance heat transfer. The effect of impinging jet positions meant that impinging onto dimples generated more and higher energetic vortices, and this led to better heat transfer performance. Cusped elliptical dimples increase the heat transfer compared to a flat plate less than the hemispherical geometry. The influence of dimple depth was also considered, the shallower dimple, d/Dd=0.15, improves significantly the heat transfer by 64% compared to that of the flat surface impingement at H/Dj=4; this result was 38% higher than that for a deeper dimple of d/Dd=0.25. The very significant increase in average heat transfer makes dimple surface impingement a candidate for cooling applications. Detailed pressure measurements will form a second part of this paper, however, plenum pressure measurements are illustrated here as well as a surface pressure measurement on both streamwise and spanwise directions.
The Unsteady Development of a Turbulent Wake Through a Downstream
Low-Pressure Turbine Blade Passage
Authors: Stieger R. D. , Hodson H. P.
Published: May 2005

This paper presents two-dimensional LDA measurements of the convection of a wake through a low-pressure turbine cascade. Previous studies have shown the wake convection to be kinematic, but have not provided details of the turbulent field. The spatial resolution of these measurements has facilitated the calculation of the production of turbulent kinetic energy, and this has revealed a mechanism for turbulence production as the wake convects through the blade row. The measured ensemble-averaged velocity field confirmed the previously reported kinematics of wake convection while the measurements of the turbulence quantities showed the wake fluid to be characterized by elevated levels of turbulent kinetic energy (TKE) and to have an anisotropic structure. Based on the measured mean and turbulence quantities, the production of turbulent kinetic energy was calculated. This highlighted a TKE production mechanism that resulted in increased levels of turbulence over the rear suction surface where boundary-layer transition occurs. The turbulence production mechanism within the blade row was also observed to produce more anisotropic turbulence. Production occurs when the principal stresses within the wake are aligned with the mean strains. This coincides with the maximum distortion of the wake within the blade passage and provides a mechanism for the production of turbulence outside of the boundary layer.
Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part II:
Heat Transfer Measurements
Authors: Christophel J. R. , Thole K. A. , Cunha F. J.
Published: May 2005

The clearance gap between a turbine blade tip and its associated shroud allows leakage flow across the tip from the pressure side to the suction side of the blade. Understanding how this leakage flow affects heat transfer is critical in extending the durability of a blade tip, which is subjected to effects of oxidation and erosion. This paper is the second of a two-part series that discusses the augmentation of tip heat transfer coefficients as a result of blowing from film-cooling holes placed along the pressure side of a blade and from dirt purge holes placed on the tip. For the experimental investigation, three scaled-up blades were used to form a two-passage, linear cascade in a low-speed wind tunnel. The rig was designed to simulate different tip gap sizes and film-coolant flow rates. Heat transfer coefficients were quantified by using a constant heat flux surface placed along the blade tip. Results indicate that increased film-coolant injection leads to increased augmentation levels of tip heat transfer coefficients, particularly at the entrance region to the gap. Despite increased heat transfer coefficients, an overall net heat flux reduction to the blade tip results from pressure-side cooling because of the increased adiabatic effectiveness levels. The area-averaged results of the net heat flux reduction for the tip indicate that there is (i) little dependence on coolant flows and (ii) more cooling benefit for a small tip gap relative to that of a large tip gap.
Nonlinear Vibration of Parametrically Excited, Viscoelastic, Axially Moving Strings
Authors: Mockensturm Eric M. , Guo Jianping
Published: May 2005

The dynamic response of parametrically excited, axially moving viscoelastic belts is investigated in this paper. Results are compared to previous work in which the partial, not material, time derivative was used in the viscoelastic constitutive relation. It is found that this added “steady state” dissipation greatly affects both the existence and amplitudes of nontrivial limit cycles. The discrepancy increases with increasing translation speed. To limit the comparison to the additional physics included in the model, the solution procedure of Zhang and Zu [1,2], who applied the method of multiple scales to the governing equations prior to discretization, is retained. The excitation here is provided by physically stretching the belt. In this case, viscoelastic behavior and excitation frequency also affects the amplitude of the tension fluctuations.
A Unified Formalism of Two-Dimensional Anisotropic Elasticity, Piezoelectricity and Unsymmetric Laminated Plates
Authors: Yin Wan-Lee
Published: May 2005

A unified formalism is presented for theoretical analysis of plane anisotropic elasticity and piezoelectricity, unsymmetric anisotropic plates, and other two-dimensional problems of continua with linear constitutive relations. Complex variables are used to reduce the governing differential equations to algebraic equations. The constitutive relation then yields an eigenrelation, which is easily solved explicitly for the material eigenvalues and eigenvectors. The latter have polynomial expressions in terms of the eigenvalues. When the eigenvectors are combined after multiplication by arbitrary analytic functions containing the corresponding eigenvalues, one obtains the two-dimensional general solution. Important results, including the orthogonality of the eigenvectors, the expressions of the pseudometrics and the intrinsic tensors, are established here for nondegenerate materials, including the case of all distinct eigenvalues. Green’s functions of the infinite domain, and of the semi-infinite domain with interior or edge singularities, are determined explicitly for the most general types of point loads and discontinuities (dislocations).
On the Use of Atmospheric Boundary Conditions for Axial-Flow
Compressor Stall Simulations
Authors: Vahdati M. , Sayma A. I. , Freeman C. , Imregun M.
Published: May 2005

This paper describes a novel way of prescribing computational fluid dynamics (CFD) boundary conditions for axial-flow compressors. The approach is based on extending the standard single passage computational domain by adding an intake upstream and a variable nozzle downstream. Such a route allows us to consider any point on a given speed characteristic by simply modifying the nozzle area, the actual boundary conditions being set to atmospheric ones in all cases. Using a fan blade, it is shown that the method not only allows going past the stall point but also captures the typical hysteresis loop behavior of compressors.
Normality Structures With Homogeneous Kinetic Rate
Laws
Authors: Yang Q. , Tham L. G. , Swoboda G.
Published: May 2005

In this paper, a homogeneous type of kinetic rate laws of local internal variables and its corresponding macroscopic behaviors, are explored within the framework of “normality structures” by Rice. Rice’s kinetic rate laws of local internal variables, with each rate being stress dependent only via its conjugate thermodynamic force, are corner stones of the normality structure. It is revealed in this paper that nonlinear phenomenological equations and Onsager reciprocal relations emerge naturally if each rate is a homogeneous function of degree q in its conjugate force. Furthermore, the nonlinear phenomenological coefficient matrix is identical to the Hessian matrix of the flow potential function in conjugate forces only scaled by q. It is further shown that the refined version of Griffith criterion proposed by Rice, (G−2γ)ȧ⩾0, can be derived from the normality structure with the homogeneous rate laws. Finally, some issues related to damage evolution laws have been discussed based on the remarkable properties.
Analysis of Doubly Clamped Nanotube Devices in the Finite Deformation Regime
Authors: Pugno N. , Ke C. H. , Espinosa H. D.
Published: May 2005

In this paper, a nonlinear theory applicable to the design of nanotube based devices is presented. The role of finite kinematics for a doubly clamped nanotube device is investigated. In particular, we analyze the continuous deformation and instability (pull in) of a clamped-clamped nanotube suspended over an electrode from which a potential differential is imposed. The transformation of an applied voltage into a nanomechanical deformation indeed represents a key step toward the design of innovative nanodevices. Likewise, accurate prediction of pull-in/pull-out voltages is highly needed. We show that an energy-based method can be conveniently used to predict the structural behavior and instability corresponding to the ON/OFF states of the device at the so-called pull-in voltage. The analysis reveals that finite kinematics effects can result in a significant increase of the pull-in voltage. This increase results from a ropelike behavior of the nanotube as a consequence of the stretching imposed by the actuation.
Analytical Solution for Shear Horizontal Wave Propagation in Piezoelectric Coupled Media by Interdigital Transducer
Authors: Wang Q. , Quek S. T. , Varadan V. K.
Published: May 2005

An analytical solution for the shear horizontal wave propagation excited by interdigital transducer in a piezoelectric coupled semi-infinite medium is developed. This solution is an extension of earlier work on wave propagation in a piezoelectric coupled plate with finitely long interdigital transducer by fully taking account of piezoelectric effects in analysis. In the current analysis, the mathematical model for a semi-infinite metal substrate bonded by a layer of interdigital transducer with infinite length is first derived. The theoretical solutions are obtained in terms of elliptic integration of the first kind and of the standard integral representation for Legendre polynomial. The essential hypothesis for the derivation of the analysis is investigated. Based on the solution for infinitely long interdigital transducer, an analytical solution for the wave propagation in this semi-infinite piezoelectric medium excited by a finitely long interdigital transducer is obtained through Fourier transform. This theoretical research can be applied to health monitoring of structures by interdigital transducer. It could also be used as a framework for the design of interdigital transducer in wave excitation of smart structures.
Interaction Between Interfacial Cavity/Crack and Internal Crack—Part II: Simulation
Authors: Prasad P. B. N. , Hasebe Norio , Wang X. F.
Published: May 2005

This paper discusses the interaction of an interfacial cavity/crack with an internal crack in a bimaterial plane under uniform loading at infinity. The point dislocation solution is used to simulate internal crack by using the distributed dislocation technique. The resulting singular integral equation is solved numerically and the stress intensity factor variations are plotted for some cases of internal crack interacting with interfacial cavity/crack.
The
zrfA
and
zrfB
Genes of
Aspergillus fumigatus
Encode the Zinc Transporter Proteins of a Zinc Uptake System Induced in an Acid, Zinc-Depleted Environment
Authors: Vicentefranqueira Rocío , Moreno Miguel Ángel , Leal Fernando , Calera José Antonio
Published: May 2005

Zinc is an essential micronutrient that cells must obtain from the environment in order to develop their normal growth. Previous work performed at our laboratory showed that the synthesis of immunodominant antigens from
Aspergillus
spp., including
A. fumigatus
, was up-regulated by a low environmental concentration of zinc. These results suggested that a tightly regulated system for the fungus to grow under zinc-limiting conditions must underlie the ability of
A. fumigatus
to acquire zinc in such environments. In this work, we show that
zrfA
and
zrfB
are two of the genes that encode membrane zinc transporters from
A. fumigatus
in this system. Expression of these genes is differentially down-regulated by increasing concentrations of zinc in the medium. Thus, the transcription of
zrfB
is turned off at a concentration 50-fold higher than that for
zrfA
transcription. In addition, phenotypic analyses of single
zrfA
Δ and
zrfB
Δ mutants and a double
zrfAzrfB
Δ mutant revealed that the deletion of
zrfB
causes a greater defect in growth than the single deletion of
zrfA
. Deletion of both genes has a dramatic effect on growth under acid, zinc-limiting conditions. Interestingly, in neutral or slightly alkaline zinc-depleted medium, the transcriptional expression of both genes is down-regulated to such an extent that even in the absence of a supplement of zinc, the expression of
zrfA
and
zrfB
is strongly reduced. This fact correlates with the growth observed in alkaline medium, in which even a
zrfAzrfB
Δ double mutant was able to grow in a similar way to the wild-type under extremely zinc-limiting conditions. In sum, the zinc transport proteins encoded by
zrfA
and
zrfB
are members of a zinc uptake system of
A. fumigatus
that operates mainly under acid, zinc-limiting conditions.
A Two-Hybrid Screen of the Yeast Proteome for Hsp90 Interactors Uncovers a Novel Hsp90 Chaperone Requirement in the Activity of a Stress-Activated Mitogen-Activated Protein Kinase, Slt2p (Mpk1p)
Authors: Millson Stefan H. , Truman Andrew W. , King Victoria , Prodromou Chrisostomos , Pearl Laurence H. , Piper Peter W.
Published: May 2005

The Hsp90 chaperone cycle catalyzes the final activation step of several important eukaryotic proteins (Hsp90 “clients”). Although largely a functional form of Hsp90, an Hsp90-Gal4p DNA binding domain fusion (Hsp90-BD) displays no strong interactions in the yeast two-hybrid system, consistent with a general transience of most Hsp90-client associations. Strong in vivo interactions are though detected when the E33A mutation is introduced into this bait, a mutation that should arrest Hsp90-client complexes at a stage where the client is stabilized, yet prevented from attaining its active form. This E33A mutation stabilized the two-hybrid interactions of the Hsp90-BD fusion with ∼3% of the
Saccharomyces cerevisiae
proteome in a screen of the 6,000 yeast proteins expressed as fusions to the Gal4p activation domain (AD). Among the detected interactors were the two stress-activated mitogen-activated protein (MAP) kinases of yeast, Hog1p and Slt2p (Mpk1p). Column retention experiments using wild-type and mutant forms of Hsp90 and Slt2p MAP kinase, as well as quantitative measurements of the effects of stress on the two-hybrid interaction of mutant Hsp90-BD and AD-Slt2p fusions, revealed that Hsp90 binds exclusively to the dually Thr/Tyr-phosphorylated, stress-activated form of Slt2p [(Y-P,T-P)Slt2p] and also to the MAP kinase domain within this (Y-P,T-P)Slt2p. Phenotypic analysis of a yeast mutant that expresses a mutant Hsp90 (T22I
hsp82
) revealed that Hsp90 function is essential for this (Y-P,T-P)Slt2p to activate one of its downstream targets, the Rlm1p transcription factor. The interaction between Hsp90 and (Y-P,T-P)Slt2p, characterized in this study, is probably essential in this Hsp90 facilitation of the Rlm1p activation by Slt2p.
Mannosyl-Diinositolphospho-Ceramide, the Major Yeast Plasma Membrane Sphingolipid, Governs Toxicity of
Kluyveromyces lactis
Zymocin
Authors: Zink Sabrina , Mehlgarten Constance , Kitamoto Hiroko K. , Nagase Junko , Jablonowski Daniel , Dickson Robert C. , Stark Michael J. R. , Schaffrath Raffael
Published: May 2005

Kluyveromyces lactis
zymocin, a trimeric (αβγ) protein toxin complex, inhibits proliferation of
Saccharomyces cerevisiae
cells. Here we present an analysis of
kti6
mutants, which resist exogenous zymocin but are sensitive to intracellular expression of its inhibitory γ-toxin subunit, suggesting that
KTI6
encodes a factor needed for toxin entry into the cell. Consistent with altered cell surface properties,
kti6
cells resist hygromycin B, syringomycin E, and nystatin, antibiotics that require intact membrane potentials or provoke membrane disruption.
KTI6
is allelic to
IPT1
, coding for mannosyl-diinositolphospho-ceramide [M(IP)
2
C] synthase, which produces M(IP)
2
C, the major plasma membrane sphingolipid.
kti6
membranes lack M(IP)
2
C and sphingolipid mutants that have reduced levels of M(IP)
2
C precursors, including the sphingolipid building block ceramide survive zymocin. In addition,
kti6/ipt1
cells allow zymocin docking but prevent import of its toxic γ-subunit. Genetic analysis indicates that Kti6 is likely to act upstream of lipid raft proton pump Kti10/Pma1, a previously identified zymocin sensitivity factor. In sum, M(IP)
2
C operates in a plasma membrane step that follows recognition of cell wall chitin by zymocin but precedes the involvement of elongator, the potential toxin target.
A Hydrophobin of the Chestnut Blight Fungus,
Cryphonectria parasitica
, Is Required for Stromal Pustule Eruption
Authors: Kazmierczak Pam , Kim Dae Hyuk , Turina Massimo , Van Alfen Neal K.
Published: May 2005

Hydrophobins are abundant small hydrophobic proteins that are present on the surfaces of many filamentous fungi. The chestnut blight pathogen
Cryphonectria parasitica
was shown to produce a class II hydrophobin, cryparin. Cryparin is the most abundant protein produced by this fungus when grown in liquid culture. When the fungus is growing on chestnut trees, cryparin is found only in the fungal fruiting body walls. Deletion of the gene encoding cryparin resulted in a culture phenotype typical of hydrophobin deletion mutants of other fungi, i.e., easily wettable (nonhydrophobic) hyphae. When grown on the natural substrate of the fungus, however, cryparin-null mutation strains were unable to normally produce its fungal fruiting bodies. Although the stromal pustules showed normal development initially, they were unable to erupt through the bark of the tree. The hydrophobin cryparin thus plays an essential role in the fitness of this important plant pathogen by facilitating the eruption of the fungal fruiting bodies through the bark of its host tree.
AUTOMATED DIAGNOSIS OF BRAIN TUMOURS ASTROCYTOMAS USING PROBABILISTIC NEURAL NETWORK CLUSTERING AND SUPPORT VECTOR MACHINES
Authors: GLOTSOS DIMITRIS , TOHKA JUSSI , RAVAZOULA PANAGIOTA , CAVOURAS DIONISIS , NIKIFORIDIS GEORGE
Published: May 2005

A computer-aided diagnosis system was developed for assisting brain astrocytomas malignancy grading. Microscopy images from 140 astrocytic biopsies were digitized and cell nuclei were automatically segmented using a Probabilistic Neural Network pixel-based clustering algorithm. A decision tree classification scheme was constructed to discriminate low, intermediate and high-grade tumours by analyzing nuclear features extracted from segmented nuclei with a Support Vector Machine classifier. Nuclei were segmented with an average accuracy of 86.5%. Low, intermediate, and high-grade tumours were identified with 95%, 88.3%, and 91% accuracies respectively. The proposed algorithm could be used as a second opinion tool for the histopathologists.
A NEURAL NETWORK MODEL FOR TRACE CONDITIONING
Authors: YAMAZAKI TADASHI , TANAKA SHIGERU
Published: May 2005

We studied the dynamics of a neural network that has both recurrent excitatory and random inhibitory connections. Neurons started to become active when a relatively weak transient excitatory signal was presented and the activity was sustained due to the recurrent excitatory connections. The sustained activity stopped when a strong transient signal was presented or when neurons were disinhibited. The random inhibitory connections modulated the activity patterns of neurons so that the patterns evolved without recurrence with time. Hence, a time passage between the onsets of the two transient signals was represented by the sequence of activity patterns. We then applied this model to represent the trace eyeblink conditioning, which is mediated by the hippocampus. We assumed this model as CA3 of the hippocampus and considered an output neuron corresponding to a neuron in CA1. The activity pattern of the output neuron was similar to that of CA1 neurons during trace eyeblink conditioning, which was experimentally observed.
PHASE DYNAMICS OF COMPLEX-VALUED NEURAL NETWORKS AND ITS APPLICATION TO TRAFFIC SIGNAL CONTROL
Authors: NISHIKAWA IKUKO , IRITANI TAKESHI , SAKAKIBARA KAZUTOSHI , KUROE YASUAKI
Published: May 2005

Complex-valued Hopfield networks which possess the energy function are analyzed. The dynamics of the network with certain forms of an activation function is decomposable into the dynamics of the amplitude and phase of each neuron. Then the phase dynamics is described as a coupled system of phase oscillators with a pair-wise sinusoidal interaction. Therefore its phase synchronization mechanism is useful for the area-wide offset control of the traffic signals. The computer simulations show the effectiveness under the various traffic conditions.
THE ROLE OF GLOBAL AND FEATURE BASED INFORMATION IN GENDER CLASSIFICATION OF FACES: A COMPARISON OF HUMAN PERFORMANCE AND COMPUTATIONAL MODELS
Authors: BUCHALA SAMARASENA , DAVEY NEIL , FRANK RAY J. , LOOMES MARTIN , GALE TIM M.
Published: May 2005

Most computational models for gender classification use global information (the full face image) giving equal weight to the whole face area irrespective of the importance of the internal features. Here, we use a global and feature based representation of face images that includes both global and featural information. We use dimensionality reduction techniques and a support vector machine classifier and show that this method performs better than either global or feature based representations alone. We also present results of human subjects performance on gender classification task and evaluate how the different dimensionality reduction techniques compare with human subjects performance. The results support the psychological plausibility of the global and feature based representation.
DYNAMICS OF BETTING BEHAVIOR UNDER FLAT REWARD CONDITION
Authors: ONZO AYAKO , MOGI KEN
Published: May 2005

One of the missions of the cognitive process of animals, including humans, is to make reasonable judgments and decisions in the presence of uncertainty. The balance between exploration and exploitation investigated in the reinforcement-learning paradigm is one of the key factors in this process. Recently, following the pioneering work in behavioral economics, growing attention has been directed to human behaviors exhibiting deviations from the simple maximization of external reward. Here we study the dynamics of betting behavior in a simple game, where the probability of reward and the magnitude of reward are designed to give a "zero" expected net reward ("flat reward condition"). No matter how the subject behaves, there is on average no change in one's resources, and therefore every possible sequence of action has the same value. Even in such a situation, the subjects are found to behave not in a random manner, but in ways showing characteristic tendencies, reflecting the dynamics of brain's reward system. Our results suggest that brain's reward system is characterized by a rich and complex dynamics only loosely coupled with external reward structure.
MODELS OF HOPFIELD-TYPE QUATERNION NEURAL NETWORKS AND THEIR ENERGY FUNCTIONS
Authors: YOSHIDA MITSUO , KUROE YASUAKI , MORI TAKEHIRO
Published: May 2005

Recently models of neural networks that can directly deal with complex numbers, complex-valued neural networks, have been proposed and several studies on their abilities of information processing have been done. Furthermore models of neural networks that can deal with quaternion numbers, which is the extension of complex numbers, have also been proposed. However they are all multilayer quaternion neural networks. This paper proposes models of fully connected recurrent quaternion neural networks, Hopfield-type quaternion neural networks. Since quaternion numbers are non-commutative on multiplication, some different models can be considered. We investigate dynamics of these proposed models from the point of view of the existence of an energy function and derive their conditions for existence.
RARE t-QUARK DECAYS $t\to c\,l_j^{+}l_k^{-}$, $t\to c\,\tilde\nu_j\nu_k$ IN THE MINIMAL FOUR-COLOR SYMMETRY MODEL
Authors: POPOV P. YU. , SMIRNOV A. D.
Published: May 2005

The rare t-quark decays [Formula: see text], [Formula: see text] via the scalar leptoquark doublets are investigated in the minimal four-color symmetry model with the Higgs mechanism of the quark–lepton mass splitting. The partial widths of these decays are calculated and the total width of the charged lepton mode [Formula: see text] and the total width of the neutrino mode [Formula: see text] are found. The corresponding branching ratios are shown to be [Formula: see text] for the scalar leptoquark masses mS = 180–250 GeV and for the appropriate values (sin β≈ 0.2) of the mixing angle of the model. The search for such decays at LHC may be of interest.
HIGHLIGHTS FROM FIVE YEARS AT THE B FACTORIES
Authors: HOU WEI-SHU
Published: May 2005

The highlights and conflicts at the B factories are briefly reviewed. CP violation was established in 2001 in B0→J/ψKS and related modes, which has now become a precision measurement of CP violation in [Formula: see text] mixing. However, the situation for the B0→π+π- and charmless b→s modes, which also probe CP violation in the decay amplitude, are not quite settled yet. They could be hinting at the presence of both strong (CP conserving) and new physics (CP violating) phases. We critically assess the developments and discuss some related discrepancies and highlights, such as observation of direct CP violation, and make a projection towards the next few years.
HAMILTONIAN ANALYSIS OF n-DIMENSIONAL PALATINI GRAVITY WITH MATTER
Authors: HAN MUXIN , MA YONGGE , DING YOU , QIN LI
Published: May 2005

We consider the Palatini formalism of gravity with cosmological constant Λ coupled to a scalar field ϕ in n dimensions. The n-dimensional Einstein equations with Λ can be derived by the variation of the coupled Palatini action provided n>2. The Hamiltonian analysis of the coupled action is carried out by a 1+(n-1) decomposition of the spacetime. It turns out that both Palatini action and Hilbert action lead to the same geometric dynamics in the presence of Λ and ϕ while the n-dimensional Palatini action could not give a dynamical formalism of connection directly.
Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude
Authors: Fulco C. S. , Kambis K. W. , Friedlander A. L. , Rock P. B. , Muza S. R. , Cymerman A.
Published: May 2005

Carbohydrate supplementation (CHOS) typically improves prolonged time-trial (TT) performance at sea level (SL). This study determined whether CHOS also improves TT performance at high altitude (ALT; 4,300 M) despite increased hypoxemia and while in negative energy balance (∼1,250 kcal/day). Two groups of fasting, fitness-matched men performed a 720-kJ cycle TT at SL and while living at ALT on days 3 (ALT3) and 10 (ALT10). Eight men drank a 10% carbohydrate solution (0.175 g/kg body wt) and eight drank a placebo (PLA; double blind) at the start of and every 15 min of the TT. Blood glucose during each TT was higher ( P < 0.05) for CHOS than for PLA. At SL, TT duration (∼59 min) and watts (∼218 or ∼61% of peak watts; %SL Wpeak) were similar for both groups. At ALT, the TT was longer for both groups ( P < 0.01) but was shorter for CHOS than for PLA on ALT3 (means ± SE: 80 ± 7 vs. 105 ± 9 min; P < 0.01) and ALT10 (77 ± 7 vs. 90 ± 5 min; P < 0.01). At ALT, %SL Wpeak was reduced ( P < 0.01) with the reduction on ALT3 being larger for PLA (to 33 ± 3%) than for CHOS (to 43 ± 2%; P < 0.05). On ALT3, O2 saturation fell similarly from 84 ± 2% at rest to 73 ± 1% during the TT for both groups ( P < 0.05), and on ALT10 O2 saturation fell more ( P < 0.02) for CHOS (91 ± 1 to 76 ± 2%) than for PLA (90 ± 1 to 81 ± 1%). %SL Wpeak and O2 saturation were inversely related during the TT for both groups at ALT ( r ≥ −0.76; P ≤ 0.03). It was concluded that, despite hypoxemia exacerbated by exercise, CHOS greatly improved TT performance at ALT in which there was a negative energy balance.
A historical review of the South African social welfare system and social work practitioners’ views on its current status
Authors: Brown Marquessa , Neku R. J.
Published: May 2005

English

The article addresses the plight of South Africa's poorest Black majority and the government's efforts to alleviate poverty. Qualitative findings associated with social work practitioners' perspectives on the success of the efforts and the use of a developmental practice approach for the reduction of poverty are discussed.

French

L'article s'intéresse au triste sort de la majorité noire la plus pauvre en Afrique du sud et aux efforts gouvernementaux en vue d'enrayer cette pauvreté. Il discute des résultats qualitatifs associés aux perspectives des praticiens en travail social sur le succès des efforts entrepris pour réduire la pauvreté et pour utiliser une approche développementale en pratique sociale.

Spanish

El artículo señala la difícil situación de los pobres en Sud Africa y los esfuerzos del gobierno para aliviar la pobreza. En él se discuten los hallazgos cualitativos, asociados con la perspectiva de los practicantes del trabajo social, sobre el desarrollo de los esfuerzos para aliviar la pobreza y la utilización de una práctica de desarrollo para aproximarse a la reducción e la pobreza.
Numerical Simulation of PU Foaming Flow in a Refrigerator Cabinet
Authors: Kim Young Bae , Kim Kyung Do , Hong Sang Eui , Kim Jong Goo , Park Man Ho , Kim Ju Hyun , Kweon Jae Keun
Published: May 2005

We have developed a numerical method for unsteady three-dimensional (3D) simulation of rigid polyurethane (PU) foaming flow in a refrigerator cabinet in this study. The governing equation for the compressible foaming flow is approximated with the Navier-Stokes equation, which means the foaming flow is assumed to be Newtonian. Numerical methods of simulation for unsteady compressible PU foaming flow with a free surface have been designed using a finite volume method (FVM) and the semi-implicit method for pressure-linked equations (SIMPLE) scheme as a pressure correction method. The formulation of numerical methods is developed on the basis of hexahedral meshes. Air in a refrigerator cabinet is neglected in the numerical method, and the free surface is traced with the volume of fluid (VOF) method. Viscosity and density of foam are assumed to be uniform in space and time-dependent, which are obtained with experimental methods. Results of numerical simulation for filling pattern and a finally filled position have been compared with the experimental results in a plate mold and a simple refrigerator cabinet. Simulation results of foaming fronts and finally filled position show good agreement with the experimental results. Numerical simulation of PU foaming flow is a useful tool to design a new refrigerator model and predict foam quality related to distance of foaming flow, air trapping, and location of finally filled position.