bluuebunny/crossref_metadata_2025 huggingface dataset:
A kiss is still a kiss?
Authors: Ward Richard , Vass Antony Andreas , Aggarwal Neeru , Garfield Cydonie , Cybyk Beau
Published: January 2005

This article explores descriptions of the sexuality and sexual expression of people with dementia residing in care. It is argued that accounts offered by care workers are mediated by their own perspectives and interests. Data from the study, alongside a review of existing research findings, suggest that gender has a crucial influence upon the interpretation and response to sexual expression in care settings. Interviews with care staff revealed that such expression is often deemed problematic. Factors maintaining the invisibility of the homosexual population in care are also discussed. It is concluded that there exists a need for greater consultation with residents regarding sexuality and for an exploration of the range of sexualities in care.
The identification of barriers to the recognition of, and response to, dementia in primary care using a modified focus group approach
Authors: Iliffe Steve , Wilcock Jane
Published: January 2005

This study reports upon the identification of barriers to the recognition of and response to dementia in primary care as perceived by general practitioners and highlights areas of information and training need. The study took a qualitative approach involving group work with 144 general practitioners in three purposively selected settings using adapted nominal group data collection methods. Six key themes were identified that explain the complexity of dementia diagnosis and management: (1) the pre-eminence of problem-solving over differential diagnosis as a working style; (2) the existence of gaps in support services; (3) problems of confidentiality; (4) the importance of ‘red flags’; (5) rules governing disclosure of diagnoses; and (6) heuristics for distinguishing dementia from normal ageing or other pathologies. In addition the practitioners identified principles governing medication use, issues around carers’ needs and implications for professional education.

The National Service Framework for Older People emphasizes the need for early detection and diagnosis of dementia in primary care. This study identified barriers to be overcome by targeted educational interventions and through service provision. There is an uneven geographical distribution of support and diagnostic services and a lack of awareness of how to access these, and this needs addressing. A stepwise educational method is recommended as opposed to promotion of a formal syllabus.
Processes and experiences of mutual support in professionally-led support groups for people with early-stage dementia
Authors: Mason Elisabeth , Clare Linda , Pistrang Nancy
Published: January 2005

Participation in a support group is increasingly offered to those diagnosed with early-stage dementia; however, empirical data about such groups for this population remain scarce. This study aimed to investigate the mutual support processes that occur in dementia support groups and how members perceive the groups. Eleven individuals from two support groups participated; three sessions of each group were videotaped and semi-structured interviews were conducted with individual members. Quantitative analysis of the videotapes indicated that only a minority of responses were classified as helping behaviours, and that facilitators played a highly active role in the group interactions. The interview data were analysed qualitatively; the themes identified related to aspects of the group that participants found helpful and unhelpful, and their perceptions of how the group operated. The findings have theoretical implications regarding the role of support groups in creating and maintaining social identities, as well as practical implications for how professionals might facilitate these groups.
End-of-life decision making in dementia
Authors: Caron Chantal D. , Griffith Jennifer , Arcand Marcel
Published: January 2005

Family caregivers are often required to make treatment decisions on behalf of institutionalized loved ones with advanced-stage dementia. Deciding on appropriate treatment is a complex process which can be difficult for families. This grounded theory study examined the concerns of family caregivers regarding their relative’s care and explored how end-of-life treatment decisions are made. Data were collected from in-depth interviews with 24 caregivers and analysed using constant comparison and dimensional analysis, resulting in a substantive theory of decision making. The role of decision maker from the perspective of family caregivers is described. The relative’s level of quality of life emerged as central to decision making. Four end-of-life phases were identified in which treatment intensity was influenced by the caregivers’ evaluation of quality of life. The results highlight the importance of including family caregivers’ experiences in working toward caregiver/medical team consensus around treatment decisions at the end of life in dementia.
Influence of copper addition on adhesive strength of Sn–3Ag–1·5Sb solder joints
Authors: Lee H.-T. , Chen M.-H. , Jao H.-M.
Published: January 2005

The present work investigates the effects of adding a small amount of Cu to Sn–3Ag–1·5Sb solders. The present results indicate that adding 0·5 and 1·0 wt-%Cu to Sn–3Ag–1·5Sb solders causes the liquidus temperature to decrease from its original value of 233·4°C to 231·6°C and to 231·4°C, respectively. Furthermore, it is noted that the addition of 1·0 wt-%Cu reduces the difference between the liquidus and solidus temperatures. It is shown that the added Cu reacts with the Sn content of the solder to form Cu6Sn5 particles in the β-Sn matrix, which are distributed non-uniformly since the Cu content is low. The experimental results also reveal that the growth rate of the solder joint interfacial intermetallic compound layers increases at higher levels of Cu addition. Finally, it is established that adding Cu to the Sn–3Ag–1·5Sb solder not only improves the adhesive strength of the solder joints, but also reduces the rate of degradation of the adhesive strength of the joints during thermal storage.
Effect of shielding gas composition on low temperature toughness of Al5083–O gas metal arc welds
Authors: Kuk J.-M. , Jang K.-C. , Lee D.-G. , Kim I.-S.
Published: January 2005

There is an ever increasing range of shielding gases, which vary from the pure gases to complex mixtures based on argon, helium, oxygen, and carbon dioxide. The commercially available gas mixtures should be considered in terms of their suitability for ensuring arc and metal transfer stability, performance, and weld quality. The objective of the present paper is to study the toughness of Al5083–O aluminium alloy, to evaluate the variation of welding zone toughness as a function of the shielding gas composition and the testing temperature. To achieve these objectives, gas metal arc welding was performed with four different shielding gas compositions (100%Ar−0%He, 67%Ar+33%He, 50%Ar−50%He, and 33%Ar+67%He), and tests were carried out at four different temperatures, namely,+25°C (+77°F), −30°C (−22°F), −85°C (−121°F), and −196°C (−321°F). The welding zone was divided into four subzones for analysis, namely, weld metal, fusion line, heat affected zone, and base metal according to the notch position. Tensile and yield strengths did not show a great effect of testing temperature at +25°C to −85°C, but increased greatly at −196°C. Also, strain tended to increase as test temperature decreased. Shielding gas composition does not have a great influence on mechanical properties. The size and number of defects were least in the 33%Ar−67%He mixture. This shows that the higher the helium gas content, the lower the number of defects detected via radiographic inspection. In the impact test, the maximum load was lowest in the weld metal and highest in the base metal at room temperature, and the maximum load and displacement were higher and lower respectively at −196°C than those at other test temperatures, showing that the lower the test temperature, the higher the maximum load, without any special features related to the phase composition being observed in the load–deflection response. The absorbed energy of the weld metal notched specimens did not depend significantly on test temperature and shielding gas mixture. Conversely, the other specimens showed that as temperature was decreased, absorption energy increased slightly up to a maximum at −85°C, but then decreased markedly at −196°C.
Weld pool geometry during keyhole laser welding of thin steel sheets
Authors: Krasnoperov M. Y. , Pieters R. R. G. M. , Richardson I. M.
Published: January 2005

In industrial applications of laser welding it is often essential to obtain full penetration welds at high processing rates using minimal heat input. Keyhole welding meets these requirements when process parameters are kept close to the boundary where complete penetration switches to partial penetration welding. In the present work weld pool behaviour at the edge of the full penetration regime has been studied. Four types of keyhole penetration mode were observed. The first type is a completely developed keyhole through the material thickness and open in the root region, whereas the second type is closed at the root. The third mode is unstable and results in intermittent penetration involving periods of open and closed keyhole conditions interspersed with periods of lack of fusion. The fourth mode is a partial penetration mode. A possible explanation of the weld pool transient behaviour is presented based on three-dimensional reconstructions of the weld pools.
In situ sintering bonding of oxide dispersion strengthened superalloys using pulsed electric current sintering technique
Authors: Nishimoto K. , Saida K. , Tsuduki R.
Published: January 2005

The in situ sintering bonding of oxide dispersion strengthened superalloys MA956 and MA754 was carried out using a pulsed electric current sintering (PECS) technique. Insert layers consisting of MA956 and MA754 powders were positioned between the respective bonding alloys, and PECS bonding was then carried out at 1023–1415 K for 0–64.8 ks applying a bonding pressure of 40–70 MPa. The number of pores between particles in the bond layer diminished with holding time. The densification behaviour of the bond layer during the PECS bonding process could be expressed by a kinetic equation with the sequential rate determining steps of plastic flow (creep) and volume diffusion. Transmission electron microscopy observations revealed that oxide strengthening particles of Y2O3 were dispersed finely and uniformly not only inside the powder particles but also at the prior particle boundaries. The creep rupture lives of MA956 and MA754 joints bonded at 1323 K for 54.0 ks and 1373 K for 64.8 ks were about 70% of that of the base metal in the longitudinal direction. The heat conduction analysis suggested that the rapid densification in PECS bonding could be attributed to the promotion of sintering by the local Joule heat generation (local increase in temperature) at the necked region. It was deduced that the superior mechanical properties of PECS bonded joints resulted from the fine and uniform dispersion of strengthening oxides in the bond layer.
Interfacial structure and bond strength of ultrasonic brazed Al–304 stainless steel dissimilar joints
Authors: El-Sayed M. H. , Hafez K. M. , Naka M.
Published: January 2005

A filler alloy (Zn–14 at.-%Al) was used to join aluminium to 304 type stainless steel by ultrasonic brazing at 673 K for different ultrasound application times. Different reaction layers could be observed at the interface, containing Fe–Al, Fe–Zn, and Al–Zn solid solutions. As the amount of these solid solutions increased at the interface, there was a gradual improvement in the joint bond strength. The maximum bond strength of 146 MPa was obtained for the Al–304 joint brazed at 673 K for 3 s ultrasound application time. A critical remaining thickness of the filler alloy after ultrasonic application improves the interfacial joining. Extending the ultrasound application time beyond 3 s causes a bulk escape of the brazing alloy from the interface and leads to a direct interaction between aluminium and 304, which increases the possibility of forming intermetallics, and consequently decreases the joint bond strength.
Interlayer growth at interfaces of Ti/Al–1%Mn, Ti/Al–4·6%Mg and Ti/pure Al friction weld joints by post-weld heat treatment
Authors: Fuji A. , Ikeuchi K. , Sato Y. S. , Kokawa H.
Published: January 2005

The interlayer growth at interfaces of Ti/Al–1%Mn and Ti/Al–4·6%Mg weld joints was studied by postweld heat treatment. The heating temperatures ranged from 676 to 873 K (400–600°C) and maximum heating time was 360 ks (100 h). The basic mechanism of interlayer growth for pure Ti/pure Al friction weld joint was also estimated. The interlayer growth rate of Ti/Al–4·6%Mg joint was much faster than for the Ti/ Al–1%Mn joint. The interlayer mainly consisted of (Al,Si)3Ti for the Ti/Al–1%Mn joint, and Al18Mg3Ti2 for the Ti/Al–4·6%Mg joint. While the interlayer grew from Al alloy substrate to the Ti side for the Ti/Al–1%Mn joint, it grew from the Ti substrate to the Al alloy side for the Ti/Al–4·6%Mg joint. The interlayer growth stopped for several hours on heating for 36 ks (10 h). Neither linear nor parabolic time-dependence relations could be exactly fit to the interlayer growth rate for both joints. The interlayer growth of Ti/Al–1%Mn was proportional to heating time raised to approximately 0·85. The crystal direction of Al3Ti interlayer growth of the Ti/Al joint was close to 〈001〉 and 〈111〉 directions obtained by OIM method. Nucleation and nuclei growth were observed at the interface of the Ti/Al joint. The nucleation and the nuclei growth are the reason for the phenomena (time dependence) described above.
Two-dimensional CFD modelling of flow round profiled FSW tooling
Authors: Colegrove P. A. , Shercliff H. R.
Published: January 2005

This paper describes the application of the computational fluid dynamics (CFD) code, FLUENT, to modelling the two-dimensional metal flow in friction stir welding (FSW). The primary goal is to assist in the development of new welding tools, though the models also improve the understanding of the deformation mechanism in FSW, and enable a first order visualisation of the flow round the probe. The paper describes a quantitative method of comparing the flow round different tool shapes. A novel ‘slip’ model was developed, where the interface conditions were governed by the local shear stresses. This revealed significant differences in behaviour when compared with the common assumption of material stick. The two-dimensional model has demonstrated the viability of the approach for investigating the flow round practical tool shapes, and gives confidence that the development of more computer intensive three-dimensional models will be justified.
Stray grain formation, thermomechanical stress and solidification cracking in single crystal nickel base superalloy welds
Authors: Park J.-W. , Vitek J. M. , Babu S. S. , David S. A.
Published: January 2005

In the present study, the effects of stray grain formation and thermomechanical stresses on solidification cracking in welds of single crystal Ni-base superalloys have been investigated. Welds were made in an asymmetric crystallographic orientation under three different processing conditions. As welding speed and power increased, stray grain formation became extensive, but only on one side of the weld. Solidification cracking also became more extensive and occurred mostly along the stray grain boundaries. The three welding processes have been simulated using the finite element method (FEM). The calculation results showed that thermomechanical stresses increase with welding speed and power, leading to increased susceptibility to cracking. These results agree well with experimental observations.
Transient liquid phase (TLP) bonding of TiAl using various insert foils
Authors: Duan H. , Koçak M. , Bohm K.-H. , Ventzke V.
Published: January 2005

TiAl intermetallic alloys have been joined using the diffusion brazing technique with Ti insert foil metal combined with Cu, Ni or Fe foils. Defect-free joints can be fabricated successfully, no matter which kind of foil combination is used as insert metal. The interface structures of the joints were also investigated and results showed various interface structures in the joined zones. A mechanism for the development of the interface structure is proposed. It is suggested that the formation process of the liquid phase was responsible for the resulting interface structures. Post-bond heat treatment (PBHT) had no obvious effect on the interface structure of the joints because of the low diffusion coefficient of Cu, Ni and Fe in the parent material. Microhardness results showed a slight decrease in the joint area as a result of PBHT.
Interfacial microstructures and temperatures in aluminium–copper electromagnetic pulse welds
Authors: Marya M. , Marya S.
Published: January 2005

Electromagnetic pulse welding can be categorised as a fast, precise, and contactless solid-state joining process. When applied to aluminium and copper, electromagnetic pulse welding opens the possibility of entirely suppressing, or at least minimising, the intermetallic phases of cracking susceptible microstructures. Metallographic examination of aluminium–copper electromagnetic pulse welds revealed that intermetallic-free joints were possible, but rare. When the collision velocity between the workpieces was high (beyond an estimated value of 170 m s−1), a hard copper rich intermetallic phase with the same composition as the equilibrium γ1-(Cu2Al) phase was detected. The presence of both this copper rich intermetallic phase and interfacial voids revealed that melting of the aluminium occurred. A simple analytical model to estimate weld interfacial temperatures was developed and applied to the electromagnetic pulse welding of aluminium with copper. The model not only demonstrated that melting (thus intermetallic phase formation) could have been expected at weld interfaces, but that the model could be extended to estimate appropriate ‘intermetallic-free’ welding conditions.
Isothermal solidification during transient liquid phase bonding of Inconel 738 superalloy
Authors: Ojo O. A. , Richards N. L. , Chaturvedi M. C.
Published: January 2005

An investigation was carried out on transient liquid phase brazing of IN-738 superalloy with Ni–Cr–B filler. Conventional models used to model the Transient Liquid Phase (TLP) bonding process assume that boride precipitation does not occur during the joining process. However, a significant deviation from this assumption was observed in all brazed samples as extensive intragranular and intergranular precipitation of chromium and boron rich particles was observed to occur within the base alloy in regions beside the braze/ base metal interface. Application of two diffusion models to the isothermal solidification stage was successful in reasonably predicting the time required to achieve complete isothermal solidification of the liquid insert, which is vital in preventing the formation of deleterious centreline eutectic. Diffusion analysis showed that the boron rich particles formed as a result of substantial solute diffusion into the base metal before equilibration of the liquid–solid phases.
Management of potential gas embolus during closure of an atrial septal defect in a three-year-old
Authors: Johnson Charles E , Faulkner Sherry C , Schmitz Michael L , Drummond-Webb Jonathan J
Published: January 2005

Gas embolism occurring in adult patients supported with cardiopulmonary bypass is usually associated with mechanical complications. Management of gas embolism is less often described for the pediatric or neonatal patient. Measures to counteract gas embolism must be undertaken immediately if a satisfactory outcome is to be achieved. Here, the management of a three-year-old female patient, who was undergoing repair of a secundum atrial septal defect when the aortic cannula became dislodged and air entered the aorta, is described. Immediate implementation of an air embolism protocol, including (among other maneuvers) removal of air from the circuit, retrograde cerebral perfusion via the superior vena cava, and induction of cerebral hypothermia, may have aided in an acceptable outcome.
Importance of internal mammary artery perfusion in cardiac ischemia and reperfusion
Authors: Ege Turan , Eskiocak Sevgi , Yuksel Volkan , Taskiran Ali , Duran Enver
Published: January 2005

Purpose: Our purpose was to investigate the changes in antioxidant defense systems due to internal mammary artery (IMA) perfusion during coronary artery bypass graft (CABG) operations in which proximal anastomoses were completed under partial bypass with the aid of a side-biting clamp.

Material and Method: Twenty-five patients to be studied were divided into two groups according to the criterion of whether during proximal anastomoses left internal mammary artery (LIMA) perfusion was applied ( n = 15, LIMA group) or not ( n = 10, non-LIMA group). The erythrocyte catalase (CAT), superoxide dismutase (SOD), serum lipid peroxidation (LPO) products and whole blood reduced glutathione (GSH) levels were measured in the blood samples taken from the coronary sinus before cardiopulmonary bypass (CPB) (t1), before declamping (t2), at the 5th min after declamping (t3), at the 5th (t4) and 15th (t5) min after removing the side-biting clamp.

Results: While erythrocyte CAT enzyme activity decreases in both groups after the basal measurements, no significant difference was detected between the groups. Although the GSH levels did not differ at t1, t2 and t3, they were found to be higher in the LIMA group at t4 ( p = 0.006) and t5 ( p = 0.021). The erythrocyte SOD enzyme activity decreased after the basal measurements in both groups, but this reduction was less in the LIMA group at t4 ( p= 0.034) and t5 ( p = 0.018) compared to the other group. LPO products rose in both groups when reperfusion started after declamping. The levels of LPO products were significantly higher at t4 and t5 in the non-LIMA group than the other group ( p = 0.011 and p = 0.008).

Conclusion: If proximal anastomoses of coronary grafts are completed under partial bypass, permitting LIMA perfusion during this procedure will be beneficial to antioxidant defense systems.
Learner proficiency and focus on form during collaborative dialogue
Authors: Leeser Michael J.
Published: January 2005

One of the challenges in content-based instruction in second language classrooms is how to focus on form in a way that is both effective and appropriate. The use of collaborative tasks that push learners to consciously reflect on their own language use (i.e., produce ‘language-related episodes’) while conveying meaning has been proposed as one way to accomplish this goal. Studies investigating the use of collaborative tasks that encourage learners to produce language-related episodes (LREs) have been shown to affect positively L2 development. However, little is known about how the proficiency of each dyad member affects how and how much dyads produce LREs during collaborative tasks. Therefore, the study reported in this article investigated how grouping learners by their relative proficiency (high-high, high-low, or low-low) affected the amount, type (lexical or grammatical) and outcome (correct, unresolved, or incorrect) of LREs produced during a passage reconstruction task, completed by twenty-one pairs of adult L2 Spanish learners from a content-based course. The findings revealed that the proficiency of the dyad members affected how much the dyads focused on form, the types of forms they focused on as well as how successful they were at resolving the language problems they encountered.
High Resolution Imaging as a Characterization Tool for Biological Crystals
Authors: STOJANOFF VIVIAN , CAPPELLE B , EPELBOIN Y , HARTWIG J , MORADELA A B , OTALORA F
Published: January 2005

Abstract:Biomolecular crystals consist of large unit cells that form a rather flexible medium that is able to accommodate a certain degree of lattice distortion, leading to several interesting issues ranging from structural to physical properties. Several techniques, from X‐ray diffraction to microscopy, have been adapted to study the structural and physical properties of biomolecular crystals systematically. The use of synchrotron‐based monochromatic X‐ray diffraction topography, with triple axis diffractometry and rocking curve measurements, to characterize biomolecular crystals is reviewed. Recent X‐ray diffraction images from gel and solution grown lysozyme crystals are presented. Defect structures in these crystals are discussed, together with reciprocal space mapping, and compared with results obtained from crystals grown in a low gravity environment.
Effects of Gravity on ZBLAN Glass Crystallization
Authors: TUCKER DENNIS S. , ETHRIDGE EDWIN C. , SMITH GUY A. , WORKMAN GARY
Published: January 2005

Abstract: The effects of gravity on the crystallization of ZrF4‐BaF2‐LaF3‐AlF3‐NaF glasses have been studied using the NASA KC‐135 and a sounding rocket. Fibers and cylinders of ZBLAN glass were heated to the crystallization temperature in unit and reduced gravity. When processed in unit gravity the glass crystallized, but when processed in reduced gravity, crystallization was suppressed. A possible explanation involving shear thinning is presented to explain these results.
Numerical Simulation and Experimental Validation of the Dynamics of Multiple Bubble Merger During Pool Boiling Under Microgravity Conditions
Authors: ABARAJITH H S , DHIR V K , WARRIER G , SON G
Published: January 2005

Abstract:Numerical simulation and experimental validation of the growth and departure of multiple merging bubbles and associated heat transfer on a horizontal heated surface during pool boiling under variable gravity conditions have been performed. A finite difference scheme is used to solve the equations governing mass, momentum, and energy in the vapor liquid phases. The vapor‐liquid interface is captured by a level set method that is modified to include the influence of phase change at the liquid‐vapor interface. Water is used as test liquid. The effects of reduced gravity condition and orientation of the bubbles on the bubble diameter, interfacial structure, bubble merger time, and departure time, as well as local heat fluxes, are studied. In the experiments, multiple vapor bubbles are produced on artificial cavities in the 2‐10 micrometer diameter range, microfabricated on the polished silicon wafer with given spacing. The wafer was heated electrically from the back with miniature strain gage type heating elements in order to control the nucleation superheat. The experiments conducted in normal Earth gravity and in the low gravity environment of KC‐135 aircraft are used to validate the numerical simulations.

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The Formation of Spikes in the Displacement of Miscible Fluids
Authors: RASHIDNIA N , BALASUBRAMANIAM R , SCHROER R T
Published: January 2005

Abstract: We report on experiments in which a more viscous fluid displaces a less viscous one in a vertical cylindrical tube. These experiments were performed using silicone oils in a vertical pipette of small diameter. The more viscous fluid also had a slightly larger density than the less viscous fluid. In the initial configuration, the fluids were at rest, and the interface was nominally flat. A dye was added to the more viscous fluid for ease of observation of the interface between the fluids. The flow was initiated by pumping the more viscous fluid into the less viscous one. The displacement velocity was such that the Reynolds number was smaller than unity and the Peclet number for mass transfer between the fluids was large compared to unity. For upward displacement of the more viscous fluid from an initially stable configuration, an axisymmetric finger was observed under all conditions. However, a needle‐shaped spike was seen to propagate from the main finger in many cases, similar to that observed by Petitjeans and Maxworthy for the displacement of a more viscous fluid by a less viscous one.
Surfactant Effect on the Buoyancy‐Driven Motion of Bubbles and Drops in a Tube
Authors: ALMATROUSHI EISA , BORHAN ALI
Published: January 2005

Abstract: The effect of surfactants on the buoyancy‐driven motion of bubbles and drops in a vertical tube is experimentally examined. The terminal velocities of fluid particles are measured and their steady shapes are quantitatively characterized in systems with various bulk‐phase concentrations of surfactant. In the case of air bubbles, the presence of surfactant retards the motion of small bubbles due to the development of adverse Marangoni stresses, whereas it enhances the motion of large bubbles by allowing them to deform away from the tube wall more easily. For viscous drops, the surfactant‐enhanced regime of particle motion becomes more pronounced in the sense that the terminal velocity becomes more sensitive to surfactant concentration, whereas the surfactant effect in the surfactant‐retarded regime becomes weaker.
Density‐Driven Instabilities of Variable‐Viscosity Miscible Fluids in a Capillary Tube
Authors: MEIBURG ECKART , VANAPARTHY SURYA H. , PAYR MATTHIAS D. , WILHELM DIRK
Published: January 2005

Abstract: A linear stability analysis is presented for variable‐viscosity miscible fluids in an unstable configuration; that is, a heavier fluid placed above a lighter one in a vertically oriented capillary tube. The initial interface thickness is treated as a parameter to the problem. The analysis is based on the three‐dimensional Stokes equations, coupled to a convection‐diffusion equation for the concentration field, in cylindrical coordinates. When both fluids have identical viscosities, the dispersion relations show that for all values of the governing parameters the three‐dimensional mode with an azimuthal wave number of one represents the most unstable disturbance. The stability results also indicate the existence of a critical Rayleigh number of about 920, below which all perturbations are stable. For the variable viscosity case, the growth rate does not depend on which of the two fluids is more viscous. For every parameter combination the maximum of the eigenfunctions tends to shift toward the less viscous fluid. With increasing mobility ratio, the instability is damped uniformly. We observe a crossover of the most unstable mode from azimuthal to axisymmetric perturbations for Rayleigh numbers greater than 105 and high mobility ratios. Hence, the damping influence is much stronger on the three‐dimensional mode than the corresponding axisymmetric mode for large Rayleigh numbers. For a fixed mobility ratio, similar to the constant viscosity case, the growth rates are seen to reach a plateau for Rayleigh numbers in excess of 106. At higher mobility ratios, interestingly, the largest growth rates and unstable wave numbers are obtained for intermediate interface thicknesses. This demonstrates that, for variable viscosities, thicker interfaces can be more unstable than their thinner counterparts, which is in contrast to the constant viscosity result where growth rate was seen to decline monotonically with increasing interface thickness.
Insulin Sensitivity and β-Cell Function in Protease Inhibitor-Treated and -Naive Human Immunodeficiency Virus-Infected Children
Authors: Bitnun Ari , Sochett Etienne , Dick Paul T. , To Teresa , Jefferies Craig , Babyn Paul , Forbes Jack , Read Stanley , King Susan M.
Published: January 2005

Previous pediatric studies have failed to demonstrate a clear association between protease inhibitor (PI) therapy and abnormal glucose homeostasis in HIV-infected children. To define more precisely the impact of PI therapy on glucose homeostasis in this population, we performed the insulin-modified frequent-sampling iv glucose tolerance test on 33 PI-treated and 15 PI-naive HIV-infected children. Other investigations included fasting serum lipids; glucose, insulin, and C-peptide; single-slice abdominal computed tomography; and, in a subset of PI-treated children, an oral glucose tolerance test.

There were no differences between the two groups with respect to fasting serum insulin or C-peptide, homeostatic model assessment insulin resistance, or quantitative insulin sensitivity check index. The mean insulin sensitivity index of PI-treated and PI-naive children was 6.93 ± 6.37 and 10.58 ± 12.93 × 10−4min−1 [μU/ml]−1, respectively (P = 0.17). The mean disposition index for the two groups was 1840 ± 1575 and 3708 ± 3005 × 10−4min−1 (P = 0.013), respectively. After adjusting for potential confounding variables using multiple regression analysis, the insulin sensitivity index and disposition index of PI-treated children were significantly lower than that of PI-naive children (P = 0.01 for both). In PI-treated but not PI-naive children, insulin sensitivity correlated inversely with visceral adipose tissue area (r = −0.43, P = 0.01) and visceral to sc adipose tissue ratio (r = −0.49, P = 0.004). Mildly impaired glucose tolerance was noted in four of 21 PI-treated subjects tested.

Our results demonstrate not only that PI therapy reduces insulin sensitivity in HIV-infected children but also that it impairs the β-cell response to this reduction in insulin sensitivity and, in a subset of children, leads to the development of impaired glucose tolerance. The presence of insulin resistance, dyslipidemia, and the significant correlation of reduced insulin sensitivity with increased visceral adipose tissue content suggest that PI-containing highly active antiretroviral therapy is associated with the emergence of early features of a metabolic syndrome-like phenotype.
Mechanical Stretch Up-Regulates the Human Oxytocin Receptor in Primary Human Uterine Myocytes
Authors: Terzidou Vasso , Sooranna Suren R. , Kim Louise U. , Thornton Steve , Bennett Phillip R. , Johnson Mark R.
Published: January 2005

Oxytocin receptor (OTR) expression is increased before the onset of labor in all models of parturition. However, the mechanisms responsible for the increase in OTR expression are uncertain. Animal data suggest that uterine stretch increases OTR mRNA expression. In primary cultures of human uterine smooth muscle cells obtained from nonpregnant (NP) women and pregnant women before (NL) and after (L) the onset of labor, we investigated the effect of stretch on the expression of OTR mRNA and DNA binding of activator protein-1 (AP-1), CCAAT/enhancer binding protein (C/EBP)β, and nuclear factor-κB transcription factors. OTR expression was least in NL, intermediate in NP, and greatest in L cells. Stretch of NL cells resulted in up-regulation of OTR mRNA expression associated with increased OTR gene promoter activity. Stretch of NP and L cells did not affect OTR mRNA expression. The increased promoter activity was associated with increased DNA binding of C/EBP and AP-1 but not nuclear factor-κB transcription factors. Overexpression of C/EBP, but not AP-1, increased OTR promoter activity. We conclude that stretch of NL cells results in increased OTR mRNA expression probably through increased C/EBPβ DNA binding. These data suggest that stretch contributes to the massive increase in OTR expression before the onset of human labor.
Androgen Insensitivity Syndrome: Somatic Mosaicism of the Androgen Receptor in Seven Families and Consequences for Sex Assignment and Genetic Counseling
Authors: Köhler Birgit , Lumbroso Serge , Leger Juliane , Audran Francoise , Grau Enric Sarret , Kurtz Francois , Pinto Graziella , Salerno Mariacarolina , Semitcheva Tatiana , Czernichow Paul , Sultan Charles
Published: January 2005

Androgen insensitivity syndrome (AIS) is caused by numerous mutations of the androgen receptor (AR) gene. The phenotype may range from partial AIS (PAIS) with ambiguous genitalia to complete AIS (CAIS) with female genitalia. In 70% of the cases, AR mutations are transmitted in an X-linked recessive manner through the carrier mothers, but in 30%, the mutations arise de novo. When de novo mutations occur after the zygotic stage, they result in somatic mosaicisms, which are an important consideration for both virilization in later life—because both mutant and wild-type receptors are expressed—and genetic counseling. We report here six patients with AIS due to somatic mutations of the AR and one mother with somatic mosaicism who transmitted the mutation twice. Of the four patients with PAIS, three presented spontaneous or induced virilization at birth or puberty. These cases underline the crucial role of the remnant wild-type AR for virilization because the same mutations, when they are inherited, lead to CAIS. We also report two novel mutations of the AR, with somatic mosaicism, detected in patients with CAIS. Thus, the remnant wild-type receptor does not always lead to virilization. In one of these patients, a high ratio of wild-type to mutant AR expression was found in the gonads and genital skin fibroblasts. Although no prenatal virilization occurred, the possibility of virilization at puberty could not be excluded, and early gonadectomy was performed. A seventh patient had a CAIS with a novel germline AR mutation. The mutation was inherited from the mother, in whom mosaicism was detected in blood and who transmitted the mutation to a second, XX, offspring. The detection of somatic AR mutations is particularly important for the clinical management and genetic counseling of patients with AIS. Before definite sex assignment, a testosterone treatment trial should be performed in all patients with PAIS, but it becomes crucial when an AR mosaicism has been detected. In patients with CAIS or severe PAIS raised as female, there is no consensus about when (early childhood or puberty) gonadectomy should be performed. When somatic AR mutations are detected, however, gonadectomy should be performed earlier because of the risk of virilization during puberty. When a germline de novo mutation is identified in the index case, the risk of transmission to a second child due to a possible germ cell mosaicism in the mother cannot be excluded. However, given the high number of AR de novo mutations and the rarity of such reports, this risk appears to be very low.
Variation of the McKusick-Kaufman Gene and Studies of Relationships with Common Forms of Obesity
Authors: Andersen Kirstine L. , Echwald Søren M. , Larsen Lesli H. , Hamid Yasmin H. , Glümer Charlotte , Jørgensen Torben , Borch-Johnsen Knut , Andersen Teis , Sørensen Thorkild I. A. , Hansen Torben , Pedersen Oluf
Published: January 2005

Obesity is a prominent feature of the Bardet-Biedl syndrome (BBS), one subset of which, BBS6, is due to mutations in the chaperonin-like gene termed the McKusick-Kaufman syndrome (MKKS) gene. We tested whether variation in MKKS contributes to common and probably polygenic forms of obesity by performing mutation analysis of the coding region in 60 Danish white men with juvenile-onset obesity. Five variants were identified, including two synonymous mutations (Pro39Pro and Ile178Ile) and three nonsynonymous variants (Ala242Ser, Arg517Cys, and Gly532Val). Furthermore, the rare Ala242Ser was identified in two families and showed partial cosegregation with obesity. The Pro39Pro, Ile178Ile, and Arg517Cys variants are in complete linkage disequilibrium and defined a prevalent haplotype. In a case-control study, the Arg517Cys polymorphism allele prevalence was 11.4% [95% confidence interval (CI), 9.7–13.0] among 744 men with juvenile-onset obesity and 9.3% (CI, 7.9–10.7) among 867 control subjects (P = 0.048). However, among middle-aged men the allelic prevalence was 9.7% (CI, 7.9–11.4) among 523 obese men and 12.2% (CI, 10.8–13.6) among 1051 lean men (P = 0.037). In conclusion, it is unlikely that MKKS variants play a major role in the pathogenesis of nonsyndromic obesity, although in rare cases the A242S allele may contribute to obesity.
The Increase of Leukocytes as a New Putative Marker of Low-Grade Chronic Inflammation and Early Cardiovascular Risk in Polycystic Ovary Syndrome
Authors: Orio Francesco , Palomba Stefano , Cascella Teresa , Di Biase Sebastiano , Manguso Francesco , Tauchmanovà Libuse , Nardo Luciano G. , Labella Donato , Savastano Silvia , Russo Tiziana , Zullo Fulvio , Colao Annamaria , Lombardi Gaetano
Published: January 2005

White blood cell (WBC) count is a known risk factor for atherosclerotic vascular disease in adult women. Polycystic ovary syndrome (PCOS) is potentially a risk factor for atherosclerosis and cardiovascular disease. The aim of the present study was to investigate leukocyte count in PCOS. One hundred and fifty PCOS women matched for age and body mass index with 150 healthy women were enrolled. WBC count, C-reactive protein, and a complete anthropometrical, metabolic, and hormonal evaluation were performed in both groups. Serum insulin, glucose level, and lipid profile were also measured in each subject. WBC count was significantly higher (P < 0.0001) in PCOS with (interquartile range in parentheses) 7260 (393) cells/mm3, compared with controls with 5220 (210) cells/mm3. C-reactive protein levels were significantly increased (P < 0.0001) in PCOS with 2 (1) mg/liter compared with healthy women with 0.7 (0.8) mg/liter. In both groups, there was a significant (P < 0.0001) linear correlation between WBC count and homeostasis model assessment score (PCOS, r = 0.94; controls, r = 0.91). Multiple linear regression analysis showed that other hormone levels are not predictors of leukocyte count both in PCOS and control women. In conclusion, our data demonstrate that PCOS women have an increased WBC count that correlates with homeostasis model assessment values.
Coexistence of Intracellular and Membrane-Bound Progesterone Receptors in Human Testis
Authors: Shah Chirag , Modi Deepak , Sachdeva Geetanjali , Gadkar Sushama , Puri Chander
Published: January 2005

Progesterone and progesterone receptors (PR) play a crucial role in female reproduction, but their roles in male reproductive physiology are largely unknown. Our previous studies demonstrated the presence of a specific membrane-bound PR in mature human spermatozoa that is known to regulate important sperm functions. The present study was undertaken to determine whether there exist PR in human testis and to investigate their molecular characteristics and expression profiles. PR mRNA and protein were detected in the spermatogenic cells, Sertoli cells, and occasionally the Leydig cells. PR protein was localized in nucleus and cytoplasm of spermatogonia, primary and secondary spermatocytes, and round spermatids in a stage-specific manner. Intense PR localization was observed in stages IV and V, whereas it was low at stages I, II, and III of spermatogenesis. RT-PCR studies revealed the presence of transcripts for PR in human testis and spermatogenic cells. In accordance with the reported molecular sizes of the known isoforms of PR, two mRNA transcripts of 3.8 and 2.8 kb for PR in adult human testis and spermatogenic cell RNA were detected by Northern blot hybridization. Western blot analysis of testicular and spermatogenic cell lysates revealed two bands of 120 and 90 kDa, corresponding to the conventional PR. In these tissue lysates, an additional band of approximately 55 kDa was detected that was also observed as a single band in sperm lysates, indicating that this smaller protein may correspond to the membrane-bound PR. The membrane-bound PR protein was demonstrated on the spermatogenic cells when probed with progesterone-bound fluorescein conjugate. The results of the present study demonstrate the existence of both intracellular PR-B and PR-A mRNA and protein in the spermatogenic cells of the human testis. A membrane-bound PR was also localized in these cells. The varying levels of intracellular PR during different stages of spermatogenesis and the presence of the membrane-bound PR imply the significance of progesterone in male reproductive events such as regulation of spermatogenesis.
Cytochrome P450 Oxidoreductase Gene Mutations and Antley-Bixler Syndrome with Abnormal Genitalia and/or Impaired Steroidogenesis: Molecular and Clinical Studies in 10 Patients
Authors: Fukami Maki , Horikawa Reiko , Nagai Toshiro , Tanaka Toshiaki , Naiki Yasuhiro , Sato Naoko , Okuyama Torayuki , Nakai Hideo , Soneda Shun , Tachibana Katsuhiko , Matsuo Nobutake , Sato Seiji , Homma Keiko , Nishimura Gen , Hasegawa Tomonobu , Ogata Tsutomu
Published: January 2005

We report on molecular and clinical findings in 10 Japanese patients (four males and six females) from eight families (two pairs of siblings and six isolated cases) with Antley-Bixler syndrome accompanied by abnormal genitalia and/or impaired steroidogenesis. Direct sequencing was performed for all the 15 exons of cytochrome P450 oxidoreductase gene (POR), showing two missense mutations (R457H and Y578C), a 24-bp deletion mutation resulting in loss of nine amino acids and creation of one amino acid (L612_W620delinsR), a single bp insertion mutation leading to frameshift (I444fsX449), and a silent mutation (G5G). R457H has previously been shown to be a pathologic mutation, and computerized modeling analyses indicated that the 15A>G for G5G could disturb an exonic splicing enhancer motif, and the remaining three mutations should affect protein conformations. Six patients were compound heterozygotes, and three patients were R457H homozygotes; no mutation was identified on one allele of the remaining one patient. Clinical findings included various degrees of skeletal features, such as brachycephaly, radiohumeral synostosis, and digital joint contractures in patients of both sexes, normal-to-poor masculinization during fetal and pubertal periods in male patients, virilization during fetal life and poor pubertal development without worsening of virilization in female patients, and relatively large height gain and delayed bone age from the pubertal period in patients of both sexes, together with maternal virilization during pregnancy. Blood cholesterol was grossly normal, and endocrine studies revealed defective CYP17A1 and CYP21A2 activities. The results suggest that Antley-Bixler syndrome with abnormal genitalia and/or impaired steroidogenesis is caused by POR mutations, and that clinical features are variable and primarily explained by impaired activities of POR-dependent CYP51A1, CYP17A1, CYP21A2, and CYP19A1.
Localization and Quantification of Cyclic Changes in the Expression of Endocrine Gland Vascular Endothelial Growth Factor in the Human Corpus Luteum
Authors: Fraser Hamish M. , Bell Julie , Wilson Helen , Taylor Paul D. , Morgan Kevin , Anderson Richard A. , Duncan W. Colin
Published: January 2005

Angiogenesis is essential for normal growth and function of the corpus luteum. The roles of various angiogenic factors in these events are being elucidated. Endocrine gland vascular endothelial growth factor (EG-VEGF) has recently been described in the human ovary. To define the localization of EG-VEGF mRNA in the corpus luteum and determine changes in its expression, dated human corpora lutea were studied at the early, mid-, and late luteal phases. Quantitative RT-PCR was employed to determine changes in EG-VEGF mRNA and compare expression to its related factor prokineticin-2 and the established angiogenic factor, VEGF. In situ hybridization was used to localize sites of production of EG-VEGF. To investigate whether expression of EG-VEGF was under the influence of LH or progesterone, luteinized granulosa cells were stimulated with human chorionic gonadotropin in the presence or absence of a progesterone synthesis inhibitor. EG-VEGF mRNA increased throughout the luteal phase, whereas there was no change in VEGF mRNA. The relative abundance of RNAs based upon PCR signal intensity showed that VEGF and EG-VEGF were highly expressed, whereas expression of prokineticin-2 was low. EG-VEGF mRNA was localized predominantly to granulosa-derived cells of the corpus luteum. Human chorionic gonadotropin stimulated both VEGF and EG-VEGF mRNA in vitro, but the level of expression was not influenced by progesterone. These results establish that in the human corpus luteum EG-VEGF is principally derived from granulosa lutein cells and that its synthesis is highest during the mid- to late luteal phase.