bluuebunny/crossref_metadata_2025 huggingface dataset:
Reversible Markov processes on general spaces and spatial migration processes
Authors: Serfozo Richard F.
Published: September 2005

In this study, we characterize the equilibrium behavior of spatial migration processes that represent population migrations, or birth-death processes, in general spaces. These processes are reversible Markov jump processes on measure spaces. As a precursor, we present fundamental properties of reversible Markov jump processes on general spaces. A major result is a canonical formula for the stationary distribution of a reversible process. This involves the characterization of two-way communication in transitions, using certain Radon-Nikodým derivatives. Other results concern a Kolmogorov criterion for reversibility, time reversibility, and several methods of constructing or identifying reversible processes.
Ruin in the perturbed compound Poisson risk process under interest force
Authors: Cai Jun , Yang Hailiang
Published: September 2005

In this paper, we study ruin in a perturbed compound Poisson risk process under stochastic interest force and constant interest force. By using the technique of stochastic control, we show that the ruin probability in the perturbed risk model is always twice continuously differentiable provided that claim sizes have continuous density functions. In the perturbed risk model, ruin may be caused by a claim or by oscillation. We decompose the ruin probability into the sum of two ruin probabilities; one is the probability that ruin is caused by a claim and the other is the probability that ruin is caused by oscillation. Integrodifferential equations for these ruin probabilities are derived when the interest force is constant. When the claim sizes are exponentially distributed, explicit solutions of the ruin probabilities are derived from the integrodifferential equations. Numerical examples are given to illustrate the effects of diffusion volatility and interest force on the ruin probabilities.
On a general class of renewal risk process: analysis of the Gerber-Shiu function
Authors: Li Shuanming , Garrido José
Published: September 2005

We consider a compound renewal (Sparre Andersen) risk process with interclaim times that have a Kn distribution (i.e. the Laplace transform of their density function is a ratio of two polynomials of degree at most n ∈ N). The Laplace transform of the expected discounted penalty function at ruin is derived. This leads to a generalization of the defective renewal equations given by Willmot (1999) and Gerber and Shiu (2005). Finally, explicit results are given for rationally distributed claim severities.
Genetic Algorithm-Based Optimal Design of Plate Fins Following Minimum Entropy Generation Considerations
Authors: Jha R. K. , Chakraborty S
Published: September 2005

This paper deals with estimation of the optimal dimensions of arrays of plate fins cooled by forced convection. The optimization is achieved by minimizing the entropy generation rate using genetic algorithm-based evolutionary computing techniques. Results are presented for staggered plate fins configuration and continuous plate fins configuration. The effects of heat transfer and fluid friction on entropy generation rate are also reported.
Optimal Synthesis of the Adjustable Knock-Out Cam-Follower Mechanism of a Bolt Former
Authors: Hwang W. M. , Yu C. Z.
Published: September 2005

This paper presents a feasible method for improvements to the adjustable knock-out cam-follower mechanism of a bolt former. On the basis of the results of analysing an existing knock-out mechanism of a bolt former, the design requirements for a new mechanism are developed. In order to meet some specific requirements and that the displacement, velocity, and acceleration curves of the follower motion are continuous, the new cam profile consists of two circular arcs and a fifth-degree or sixth-degree polynomial segment. For the cam profile with a sixth-degree polynomial segment, besides the six specified boundary conditions, a variable condition is used as a design variable for the optimization design. The maximum strike velocity between the knock-out screw and knock-out pin for all knock-out strokes is minimized by using the golden section method. The kinematic characteristics of the new knock-out camfollower mechanism synthesized are better than those of the existing mechanism. The method presented is illustrated by an example.
Online Discretization of Continuous-Valued Attributes in Rule Induction
Authors: Pham D. T. , Afify A. A.
Published: September 2005

Machine learning algorithms designed for engineering applications must be able to handle numerical attributes, particularly attributes with real (or continuous) values. Many algorithms deal with continuous-valued attributes by discretizing them before starting the learning process. This paper describes a new approach for discretization of continuous-valued attributes during the learning process. Incorporating discretization within the learning process has the advantage of taking into account the bias inherent in the learning system as well as the interactions between the different attributes. Experiments have demonstrated that the proposed method, when used in conjunction with the SRI rule induction algorithm developed by the authors, improves the accuracy of the induced model.
Circular Couette Flow between Porous Cylinders
Authors: Djordjevic V. D.
Published: September 2005

Circular Couette flow between porous cylinders is treated in this paper. Exact solutions of Navier-Stokes equations for the flow in the gap between cylinders and of Darcy-Brinkman-Lapwood equations for the flow in porous rings are found analytically by matching velocities and stresses on the porous boundaries, without making any previous assumptions concerning the slip velocities. In the special case in which the inner cylinder is fully porous and stationary, and the outer cylinder is fully rigid and rotating, the torque exerted by the rotation of the outer cylinder on the inner one is found, and it is shown how the effective viscosity of the liquid can be determined in possible experiments.
Influence of Thermal Deformations in the Solid Laser Medium on the Emitted Radiation Parameters
Authors: Donţu O , Ganatsios S , Duminica D
Published: September 2005

The paper presents some remarks about the way in which the thermal deformation in the solid active laser medium influences the radial distribution of the emitted laser beam intensity, implicitly the processing parameters.
Centre-Line Deviation as a Measure of Camber in Steel Slabs During Unrestricted Horizontal Rolling
Authors: Montague R. J. , Watton J , Brown K. J.
Published: September 2005

A theoretical analysis of slab motion during camber evolution in unrestricted horizontal rolling is presented. The analysis shows that a linear relationship exists between centre-line deviation (CLD) curvature and outgoing camber, which is a function of ingoing and outgoing slab thickness and ingoing slab camber.
Integrated Design Methodology for High-Precision/Speed Servomechanisms
Authors: Kim M-S , Chung S-C
Published: September 2005

An integrated design method for a high-precision/speed servomechanism including interactions of mechanical and electrical subsystems is proposed in this article. On the basis of the multiobjective optimization method, a non-linear optimal design procedure of the mechanical subsystem is performed simultaneously through the design process of the electrical subsystem satisfying the desired performance. Mechanical and electrical constraints have been formulated according to design requirements. Both mechanical and electrical parameters are considered as design variables. Validity of the integrated design problem is verified on the different application areas. Parametric studies of the design variables have also been conducted in this article. Case studies show that the integrated design method for an x-y positioning system satisfies the desired high-precision/speed performance.
Torques for Electromechanical Integrating Toroidal Drive
Authors: Xu L , Huang J
Published: September 2005

In this study, an electromechanical integrating toroidal drive is proposed and its operating principle is introduced. The equations of electromechanical coupled force and the rotor torque for the drive are given by means of electromagnetic theory and mechanical principle. The influenced factors of the rotor torque are analysed and their influences are obtained. There are periodic changes in the rotor torque and the change mainly depends on the tooth number of planet. The changes of the rotor torque along with mechanical and electric parameters of the drive and the limit-driving torque of the drive are presented. The limit driving torque is influenced by rotating angle of the planet and other factors. The minimum limit value decides the load-carrying ability of the drive. The equal-limit torque conditions between planet-worm and planet-stator are discussed. In order to obtain the equal-limit torque, a deterministic relation should be met among the current of the worm, the magnetic induction intensity of the permanent magnet stator, and the airgap thickness.
Experimental and Numerical Investigations on the Air-Pumping Phenomenon in High-Speed Spur and Helical Gears
Authors: Diab Y , Ville F , Houjoh H , Sainsot P , Velex P
Published: September 2005

An approximate hydrodynamic model of the air-lubricant pumping by spur and helical gears, which makes it possible to predict the compression-expansion process by the meshing teeth, is presented. The simulated pressure patterns correlate well with the experimental evidence obtained from a specific test rig for both spur and helical gears. Finally, it is shown that this pumping phenomenon can generate significant power losses, especially for high-speed applications.
The Limaçon of Pascal: Mechanical Generation and Utilization for Fluid Processing
Authors: Sultan I. A.
Published: September 2005

The limaçon of Pascal is a plane curve that possesses some characteristics which qualify it for fluid processing applications. However, the curve has not yet attracted enough attention, neither from industry nor from the mechanical engineering research community, despite the few attempts that have been conducted over the past century. The work presented here is intended to explore various mechanical linkages that can be employed to produce the limaçon and the aspects of these linkages. Mathematical analysis will show that machines based on the limaçon curve possess sinusoidal volumetric relationships and hence, simplified pressure and torque equations can be obtained in closed forms. The concepts discussed here will be demonstrated by using a compressor as a sample application.
Surface Tension Effects on Liquid Flow in Small Plastic Tubes When Gas Bubbles are Present
Authors: Myers M. R. , Cave H. M. , Krumdieck S. P.
Published: September 2005

Two-phase intermittent gas and liquid slug flow in small diameter glass and plastic tubes was studied. Two distinct flow regimes and the transition phenomena were identified. A modified Hagen-Poiseuille relation was derived to describe the extremely high pressure drop due to the surface tension effects of pinned slug flow.
A Numerical Study of the U-Turn Bend in Return Channel Systems for Multistage Centrifugal Compressors
Authors: Oh J. M. , Engeda A , Chung M. K.
Published: September 2005

A qualitative numerical study of the flow in the U-turn bend of return channel systems for multistage centrifugal compressors is presented. Calculations have been carried out using the flow analysis program FLUENT. The flow in the U-turn bend is highly three-dimensional and complex. The main cause for this is the circumferential variation of the velocity profile at the inlet of the bend. The circumferential variation of the velocity profile is an unavoidable result from the wake/jet flow at the exit of the impeller. In this article, first the effect of the wake/jet flow coming into the U-turn bend is studied. It is shown that the wake/jet flow develops to form the secondary flow in the U-turn bend. The secondary flow, with the high streamline curvature of the flow in the bend, makes the flow inside the bend highly complex. This complex flow is hard to predict with conventional turbulence models that have been developed on the basis of near homogeneity of flows. Comparing the present result with a study that successfully predicted the loss and flow behaviour in the bend, a discussion is presented on the turbulence and the turbulence models. Also, the loss mechanisms in the U-turn bend are discussed in detail.
Validation of EHL Contact Predictions under Time Varying Load
Authors: Venner C. H. , Wijnant Y. H.
Published: September 2005

In this paper, it is investigated how accurately current models predict the response of an elasto-hydrodynamically lubricated contact to time varying load conditions. For two patterns of time varying load, under conditions of pure rolling, the results obtained experimentally on a ball on disk interferometry apparatus by Sakamoto et al. (Behaviour of point contact EHL films under pulsating loads. Proceedings of the 30th Leeds-Lyon Symposium on Tribology, Elseviers Tribology Series, Vol. 43, pp. 391-399) are compared with the results of numerical simulations using the dynamic contact model of Wijnant (Contact dynamics in the field of elastohydro-dynamic lubrication. PhD Thesis, University of Twente, Enschede, The Netherlands, 1998 ISBN 90-36512239), Wijnant and Venner (Contact dynamics in starved elastohydrodynamic lubrication. Proceedings of the 25th Leeds-Lyon Symposium on Tribology, Elsevier Tribology Series, Vol. 36, pp. 705-716). The observed film changes are explained and related to the piezoviscous behaviour of the lubricant. Results for two different viscosity pressure relations are presented. It is shown that the details of the viscosity pressure relation have little effect on the local phenomena observed. The agreement between experimental and theoretical results is excellent in terms of the location and width of induced film thickness changes. The accuracy of the amplitude of the predicted changes is less. A amore accurate amplitude prediction requires more precise knowledge of the dynamic parameters, which describe the load system used in the experiments.
EHL Film Thickness Computations at Low Speeds: Risk of Artificial Trends as a Result of Poor Accuracy and Implications for Mixed Lubrication Modelling
Authors: Venner C. H.
Published: September 2005

When numerical and experimental results are compared to validate elasto-hydrodynamic lubrication (EHL) models, it is of utmost importance that grid-converged results are used. In particular at low speeds and high loads, solutions obtained using grids that are not sufficiently dense will exhibit an artificial trend that does not represent the behaviour of the continuous modelling equations. As it coincides with a trend observed in experiments this may lead to the erroneous conclusion that the theoretical model on which the numerical simulations are based is accurate. This risk is illustrated in detail. It is further shown that EHL models based on the Reynolds equation in a steady state circular contact predicts a positive film thickness as long as the grid used in the calculations is sufficiently dense. This has significant implications for the validity of results obtained using mixed lubrication models based on a Reynolds model and a film thickness threshold.
Influence of Journal Misalignment Caused by Shaft Deformation under Rotational Load on Performance of Journal Bearing
Authors: Sun Jun , Gui Changlin , Li Zhiyuan , Li Zhen
Published: September 2005

A method to analyse lubrication performance of journal bearing considering journal misalignment caused by shaft deformation under rotating load in a shaft-bearing system was established and validated by special experiments on a developed experimental rig of journal bearing. The experimental results show that the proposed analytical formulation and method can meet the researching requirements. Oil film pressure, end leakage flowrate, and friction coefficient of journal bearing at variant journal misalignment caused by shaft deformation under rotating load were calculated. The results show that journal misalignment makes obvious difference to distribution of film pressure and film thickness. The maximum film pressure increases markedly. The minimum film thickness reduces. End leakage flowrate increases. Friction coefficient of journal slightly changes. Therefore, in order to make the calculation of journal bearing more realistic and to achieve more reasonable design in shaft-bearing system, the influence of shaft deformation under load should be considered in lubrication analysis of journal bearing in a shaft-bearing system.
Comparison of Stopping Modes for Pod-Driven Ships by Simulation Based on Model Testing
Authors: Woodward M D , Atlar M , Clarke D
Published: September 2005

Conventionally, the stopping of a ship is achieved by direct reversal of propeller rotation. However, the introduction of azimuthing pods presents other options. The following study examines the various modes that may be employed to stop a pod-driven ship. A continuous function is derived describing the hydrodynamic forces on both the propeller and the pod body for any load condition and helm angle, including fluid damping and added mass effects. The proposed function is validated through comparison with comprehensive open water model tests. Next, a time domain simulation algorithm is proposed to examine the dynamic effects including the mass inertia on both the propeller shaft and slewing stock. Finally, a simulation study for the proposed stopping modes is performed using a known design as a case study. Results and discussion are presented.
Information System for Structural Integrity of Ships
Authors: Kawamura Y , Sumi Y
Published: September 2005

The maintenance of ship structures is very important to avoid serious casualties such as oil spill from tankers. For this reason, it is necessary to detect and evaluate the state of the damages properly. In this paper, a new concept of an information system for structural integrity of ships is proposed in order to improve the safety and to assess the condition of structural strength in service. In this system, all information of damages in a certain ship obtained from hull surveys is managed in an information database, allowing assessments to be made at any time in the ship's life of the present structural integrity status or provisions to be made for the future. By using the proposed concept it becomes possible to provide a valuable tool for repair management and planning. One of the advantages of this concept is that reasonable and advanced assessment of an aged ship is readily achievable by using the information about damages and the three-dimensional structural data stored in the database. Based on the proposed concept, a prototype system for the evaluation of corrosion damages is developed by using the STEP (standard for the exchange of product model data) technologies with the proposal of a data model of the information system. Also, a method for the import of ship structural data into the database is studied for practical development of the system. Moreover, a framework for the generation of analysis models for strength of aged ships is proposed, by which labour saving is possible using a generating analysis model. The validity of the effectiveness of the proposed concept is shown with some examples.
Geometric Considerations for the Design of Production-Friendly High-Speed Ship Hull Forms
Authors: Boyd S W , Day A H , Winkle I E
Published: September 2005

This study examines the feasibility of designing high-speed ships with hull-form geometry suitable for planked construction, with the aim of reducing the hull construction cost. An algorithm is developed for placing prismatic planks on to a three-dimensional hull form to represent a planked construction. A number of well-known hull forms are examined using the algorithm developed in order to assess their suitability for this construction technique. It is shown that typical round-bilged forms are unsuitable for planked construction, since an undesirably large proportion of the material strength will be used in forming the structure. A conceptual design for a simplified hull form is developed which contains significantly reduced levels of double curvature, and this design is shown to be suitable for planked construction, as well as offering the potential for advantages in conventional plated construction. It is further shown that the hydrodynamic resistance of this conceptual design is comparable with a more traditional form.
Experience with mouse hepatitis virus sanitation in three transplantable murine tumour lines
Authors: Dagnæs-Hansen F , Horsman M R
Published: September 2005

Transmission of viral infection by tumour lines or other biological materials may have confounding effects on research. Many research organizations require screening for viral agents of all cell lines, tumours, sera and other biologicals before implantation or inoculation into animal models. Screening for viral contamination is done by the mouse antibody production (MAP) test, by cell culture, or alternatively by direct detection of the viral agents by polymerase chain reaction (PCR). The description of procedures for sanitation of infected cell lines or tumours is sparse. The present report describes the procedures used for sanitation of three transplantable murine tumour lines, which were transplanted in vivo in a mouse hepatitis virus (MHV)-infected colony of mice at the Department of Experimental Clinical Oncology (DECO). The tumours were frozen and serially transplanted three times in a quarantine colony of syngenic mice. Serological examination of the mice transplanted with tumours as well as their cage mates in the quarantine colony did not detect any antibodies against MHV. After repeated serial transplantation in seronegative animals, tumour material was frozen and thawed tumours were later used for transplantation into the newly established virus-free colony of mice at DECO. PCR-based detection of MHV did not reveal any contamination of the tumour examined by this technique, indicating that this murine tumour apparently did not transmit MHV or that MHV was eliminated from the tissue so fast after the infection that it could not be transmitted by the tumour tissue. It is concluded that MHV infection of mice with transplantable murine tumours does not necessarily cause the tumours to be contaminated.
The role of hair in swimming of laboratory mice: implications for behavioural studies in animals with abnormal hair
Authors: Kalueff A V , Tuohimaa P
Published: September 2005

Animal swimming tests, such as the forced swim test, are extensively used in biomedical research to study rodent behaviour. Hair and skin exposed to water may be an important factor affecting the performance in this test. Since various hair and skin abnormalities are not uncommon in genetically modified or drug-treated laboratory animals, this test may be inappropriate for these animals. Because on occasions it is necessary to screen their swimming behaviour, in the present study we aimed to assess the role of hair in swimming of laboratory rodents in the forced swim test, widely used in behavioural research. For this, we shaved laboratory mice (129S1 strain) and compared their swimming patterns with those of unshaven controls. Overall, shaving mice did not affect their swimming behaviours in the 5 min forced swim test. Our results indicate that hair condition is not an important factor in the forced swim test for this mouse strain, and suggest that this test may have wider utility for behavioural analyses of mice with abnormal hair.
Monitoring a mouse colony for Helicobacter bilis using a Helicobacter-genus-specific nested PCR
Authors: Jacobsen K , Mahabir E , Brielmeier M , Wilhelm P , Seidel K E , Schmidt J
Published: September 2005

Although Helicobacter infections of laboratory mice are usually subclinical, they may interfere with in vivo experiments and thus may lead to misinterpretation of data. As such, it is important to provide a means to unequivocally identify infections with murine Helicobacter spp. In the present study, a nested polymerase chain reaction (PCR) was established and shown to be 10 to 100 times more sensitive than the single-step PCR commonly used for routine diagnosis of Helicobacter spp. Experimental infection of Helicobacter-free mice demonstrated that faeces, caecum, colon and rectum but not liver are equally suitable for the detection of H. bilis. However, use of faecal pellets is advantageous since detection of H. bilis is possible one week after infection and analysis of faeces instead of tissues avoids euthanasia of animals. Furthermore, it generates representative data for all animals housed in the same cage and analysis can be repeatedly performed. Use of samples from breeding pairs but not offspring provides representative information about the Helicobacter status of a mouse colony. Both C3H/HeJ and C57BL/6 mice appear to be susceptible to H. bilis and persistent infection was observed during the 20-week experimental period. Analysis of pooled faecal pellets by nested PCR seems to be the most sensitive approach for H. bilis monitoring of the given breeding colony.
A novel model for the investigation of orthotopically growing primary and secondary bone tumours using intravital microscopy
Authors: Klenke F M , Merkle T , Fellenberg J , Abdollahi A , Huber P E , Gebhard M M , Ewerbeck V , Sckell A
Published: September 2005

Here is reported the development of an experimental model using intravital microscopy as a tool to orthotopically investigate malignant bone tumours. Although up to 85% of the most frequently occurring malignant solid tumours, such as lung and prostate carcinomas, metastasize into the bone, and despite the knowledge that a tumour's course may be altered by its surrounding tissue, there is no adequate experimental model available enabling the investigation of orthotopically grown bone tumours in vivo. Intravital microscopy is an internationally accepted experimental method, used in various acute and chronic animal models, that enables qualitative and quantitative analysis of the angiogenesis, microcirculation, growth behaviour, etc. of various benign and malignant tissues. Non-invasive investigations of up to several weeks are possible. Additionally, tissue samples can be taken after termination of the in vivo experiments for further ex vivo investigation (histology, immunohistochemistry, molecular biology, etc.), elucidating the mechanisms that underlie the in vivo observations. Severe combined immunodeficient mice were fitted with a cranial window preparation where the calvaria served as the site for orthotopic implantation of the solid human tumours Saos-2 osteosarcoma (primary) and A 549 lung carcinoma and PC-3 prostate carcinoma (secondary). In all preparations, the take rate was 100%. Histological assessment confirmed the data obtained in vivo, showing typical tumour growth with infiltration of the surrounding osseous and soft tissues. This novel model serves as a valuable tool in understanding the biology of primary and secondary bone tumours in physiological and pathophysiological situations, with implications for the most areas of tumour therapy such as chemotherapy, radiation and antiangiogenesis.
Germfree status of mice obtained by embryo transfer in an isolator environment
Authors: Inzunza José , Midtvedt Tore , Fartoo Mona , Norin Elisabeth , Österlund Ewa , Persson Anna-Karin , Ährlund-Richter Lars
Published: September 2005

The technique of embryo transfer has been evaluated for the purpose of changing the mouse stocks to a germfree (GF) status. Our results show reproducible and quality-assured conversion of animals to those which are negative for the presence of microorganisms. Rapid and easy access to GF mice is advantageous for studies of selected microflora and their cross-talks with the host, when applying, e.g. genomic, proteomic and metabolic methodology.

The study involved embryo transfer in an isolator environment, thereby allowing implantation of cleansed embryos into GF recipients under well-controlled conditions. The recipient females gave birth normally and took care of the offspring as if they were their own pups, thus enhancing the survival rate. Access to full technical resources required to maintain GF isolators are, however, a prerequisite. In this study, we used stainless steel isolators designed by Gustafsson (1959), on which a stereomicroscope was mounted to facilitate embryo transfer inside the isolator.

The use of embryo transfer and isolator techniques will facilitate the availability of various mouse mutant models under different gnotobiotic conditions, GF, monoxenic or polyxenic animals, to enable comparison with conventional animals for physiological and pathophysiological studies.
Optimization of the MB49 mouse bladder cancer model for adenoviral gene therapy
Authors: Loskog A , Ninalga C , Hedlund T , Alimohammadi M , Malmström P-U , Tötterman T H
Published: September 2005

Bladder cancer is regarded as a promising candidate for innovative therapies in the field of immune and gene therapy. In this paper, we present the subcutaneous, metastatic and a novel orthotopic model of murine MB49 bladder cancer in C57BL/6 mice. We further show the potential of using adenoviral vectors together with different transduction enhancers to augment in vivo gene delivery. Finally, we present candidate genes for tumour detection, therapy or targeting.

The MB49 tumour grew rapidly in mice. The subcutaneous model allowed for tumour detection within a week and the possibility to monitor growth rate on a day-by-day basis. Injection of MB49 cells intravenously into the tail vein gave rise to lung metastases within 16 days, while instillation of tumour cells into pretreated bladders led to a survival time of 20–40 days. Adenoviral vectors can be used as a vehicle for gene transfer to the bladder. By far, the most potent transduction enhancer was Clorpactin, also known as oxychlorosene. Last, we show that MB49 cells express tumour-associated antigens like bladder cancer-4, prostate stem cell antigen and six-transmembrane epithelial antigen of the prostate.

Given the possibility for efficient genetic modification of the bladder and the presence of known tumour antigens, the MB49 models can be used in innovative ways to explore immunogene therapy.
Running wheel choice by Syrian hamsters
Authors: Reebs S G , St-Onge P
Published: September 2005

The present study investigated the preference of male and female Syrian hamsters, Mesocricetus auratus, for different types of running wheels. Hamsters were placed individually in sets of multiple cages linked by tunnels, each cage with a different running wheel. The number of wheel revolutions in each cage was tallied daily over 40 days. The hamsters did not express a preference when offered a choice of a running surface made of metal rods spaced 9 mm apart and a similar running surface covered in plastic mesh to prevent the possible slippage of feet between the rods. The hamsters did express a clear preference for larger wheels (35 versus 23cm diameter), and for completely circular wheels over truncated ones. They neither favoured nor rejected wheels with small obstacles along the running surface. In all experiments, preferences were more strongly expressed by males than by females. Running wheels for hamsters may be improved by enlarging their diameter (to the standards often used for rats, if practically possible) and by ensuring good footing on the running surface (a space no larger than 9 mm between evenly spaced rods seems sufficient to achieve this, at least in large wheels and for hamsters older than 55 days). Installing obstacles along the running surface does not appear to make the wheel more interesting to hamsters.
Identification and analysis of U5 snRNA variants in Drosophila
Authors: CHEN LI , LULLO DENNIS J. , MA ENBO , CELNIKER SUSAN E. , RIO DONALD C. , DOUDNA JENNIFER A.
Published: September 2005

Distinct isoforms of spliceosomal RNAs may be involved in regulating pre-messenger RNA splicing in eukaryotic cells. During a large-scale effort to identify small noncoding RNAs in Drosophila, we isolated a U5 snRNA-like molecule containing a 5′ segment identical to that of the canonical (major) U5 snRNA but with a variant Sm binding site and a distinct 3′ hairpin sequence. Based on this finding, another six similar U5 snRNA-like sequences were identified within the Drosophila genome by sequence similarity to the invariant loop in the 5′ half of U5. Interestingly, although all of these variants are expressed in vivo, each shows a distinct temporal expression profile during Drosophila development, and one is expressed primarily in fly heads. The presence of these U5 snRNA variants within RNP particles suggests their role in splicing and implies a possible connection to regulation of developmental and tissue-specific gene expression.
Nonsense-mediated mRNA decay factors act in concert to regulate common mRNA targets
Authors: REHWINKEL JAN , LETUNIC IVICA , RAES JEROEN , BORK PEER , IZAURRALDE ELISA
Published: September 2005

Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that degrades mRNAs containing nonsense codons, and regulates the expression of naturally occurring transcripts. While NMD is not essential in yeast or nematodes, UPF1, a key NMD effector, is essential in mice. Here we show that NMD components are required for cell proliferation in Drosophila. This raises the question of whether NMD effectors diverged functionally during evolution. To address this question, we examined expression profiles in Drosophila cells depleted of all known metazoan NMD components. We show that UPF1, UPF2, UPF3, SMG1, SMG5, and SMG6 regulate in concert the expression of a cohort of genes with functions in a wide range of cellular activities, including cell cycle progression. Only a few transcripts were regulated exclusively by individual factors, suggesting that these proteins act mainly in the NMD pathway and their role in mRNA decay has not diverged substantially. Finally, the vast majority of NMD targets in Drosophila are not orthologs of targets previously identified in yeast or human cells. Thus phenotypic differences observed across species following inhibition of NMD can be largely attributed to changes in the repertoire of regulated genes.
Detecting protein-induced folding of the U4 snRNA kink-turn by single-molecule multiparameter FRET measurements
Authors: WOŹNIAK ANNA K. , NOTTROTT STEPHANIE , KÜHN-HÖLSKEN EVA , SCHRÖDER GUNNAR F. , GRUBMÜLLER HELMUT , LÜHRMANN REINHARD , SEIDEL CLAUS A.M. , OESTERHELT FILIPP
Published: September 2005

The kink-turn (k-turn), a new RNA structural motif found in the spliceosome and the ribosome, serves as a specific protein recognition element and as a structural building block. While the structure of the spliceosomal U4 snRNA k-turn/15.5K complex is known from a crystal structure, it is unclear whether the k-turn also exists in this folded conformation in the free U4 snRNA. Thus, we investigated the U4 snRNA k-turn by single-molecule FRET measurements in the absence and presence of the 15.5K protein and its dependence on the Na+ and Mg2+ ion concentration. We show that the unfolded U4 snRNA k-turn introduces a kink of 85° ± 15° in an RNA double helix. While Na+ and Mg2+ ions induce this more open conformation of the k-turn, binding of the 15.5K protein was found to induce the tightly kinked conformation in the RNA that increases the kink to 52° ± 15°. By comparison of the measured FRET distances with a computer-modeled structure, we show that this strong kink is due to the k-turn motif adopting its folded conformation. Thus, in the free U4 snRNA, the k-turn exists only in an unfolded conformation, and its folding is induced by binding of the 15.5K protein.
Pharmaceutical Prescribing for Children
Authors: Randall Christine
Published: September 2005

This paper, the second in a series to be published in Primary Dental Care, addresses the issues of prescribing analgesics for children and the control of pain. It is crucial to remember that in infants and children, as in adults, pain, anxiety and fear are often associated. All concerned with the care of children have a duty to anticipate and avoid, as well as to relieve pain.1
Description of a System Designed to Assist Primary Dental Care Clinicians in Decision-Making with Regard to Specialist Periodontal Referrals and Report of Two Clinical Audits using the System
Authors: Snoad Richard
Published: September 2005

Introduction

Identifying which patients are at risk of significant periodontal breakdown and may need specialist care is a process fraught with problems. This paper summarises factors that should be considered by referring clinicians, describes a system to assist them, and presents the results of two sequential audits carried out in general dental practice using the system.

Aims, Materials and Methods

The author aims to present the system and the results of two sequential audits, carried out in the same eight general dental practices by 23 general dental practitioners (GDPs) after training from a specialist in periodontics. The system is based on the use of the Basic Periodontal Examination (BPE), a constant pressure periodontal probe, and a computer screen that prompts the clinician who is performing periodontal screening. A series of risk factors, including smoking, presence of relevant systemic disease and age, is used to modulate the score. Patients are then classified into one of three complexity groups. Those in the Complexity 3 group are deemed to be potentially at risk of significant periodontal breakdown and in need of referral for specialist advice and/or care, in accordance with the published British Society of Periodontology guidelines. In each audit a random sample of the records of ten dentate patients over the age of 20 years, who attended for recall or new examinations by each of the 23 GDPs over a calendar month, were assessed to see whether or not BPE scores had been recorded and whether or not those classified as Complexity 3 (and in need of referral) had been correctly identified and referred.

Results

In both audits the total random sample of patient records was 225 (ten for 22 dentists and five for the remaining dentist who only worked for a short time during the months of the audit). In the first audit cycle 139 (62%) of the random sample of records included a BPE score and 11 (8%) of the patients concerned were identified as Complexity 3 and referred for specialist advice and/or treatment. All 11 accepted the referral and when examined by the specialist in periodontics were confirmed as Complexity 3. In the second audit cycle, which took place seven months later, 179 (80%) of the random sample of patient records included a BPE score and 14 patients were assessed by their GDPs as being Complexity 3. All 14 accepted a referral and were deemed to be Complexity 3 when they were subsequently examined by the specialist in periodontics.

Conclusion

Although the full potential of the system was not investigated during the two audits, these preliminary results suggest that it may assist referring clinicians in identifying which patients to refer and encourage clinicians to perform periodontal screening.
Developing the First Dental Care Pathway: The Oral Health Assessment
Authors: Hally Jennifer D , Pitts Nigel B
Published: September 2005

In this paper the authors define the concept of care pathways and explain what they are and how they have been applied in various areas of healthcare. The authors discuss the benefits of the care pathway approach and outline the first national dental NHS (clinical) care pathway and its link to National Institute for Clinical Excellence (NICE) guidance on dental recall intervals.

The authors go on to explain that as a result of one of the key recommendations of Options for Change, the concept of care pathways will be extended to the primary dental services of the NHS. The first care pathway will be the Oral Health Assessment (OHA). The authors describe the development of, and rationale for, the OHA and provide details of its planned introduction.

The authors conclude that the OHA should act as the initial interface between the primary care team and the dental patient. In so doing it should enable a change in the focus of care, from treatment-based to more prevention-led, personalised care appropriate to the specific needs of individual patients.
Launch of Key Skills in Primary Dental Care
Authors: Eaton Kenneth A
Published: September 2005

On the morning of Tuesday, 21st June 2005 an audience of approximately 150 attended the launch of the Faculty of General Dental Practice (UK)'s Key Skills in Primary Dental Care e-learning programme. This package consists of seven modules each of which deals with a skill that is fundamental to the safe practice of clinical dentistry, not just in primary care, as the title suggests, but all areas including primary and secondary care. The package is available as a series of seven CD-ROMs or online at a protected website.

The seven key skills are:

• Infection control.

• Legislation and good practice guidelines.

• Clinical record keeping.

• Team training.

• Radiography.

• Risk management and communication.

• Medical emergencies.

The launch consisted of a series of short presentations followed by a question and answer session.
Pharmaceutical Prescribing for Children
Authors: Randall Christine , Palmer Nikolaus OA
Published: September 2005

This paper is the first in a series which will review the current literature and evidence upon which primary care dentists should base their decisions to prescribe medication for children. As such it will offer guidance and suggest current best practice. The series has been edited by Dr Nikolaus Palmer.

This first paper deals with general principles. A second paper on prescribing for children with regard to pain and analgesia also appears in this edition of Primary Dental Care. Future papers will address prescribing for children with relation to:

• Fungal and viral infections.

• The management of paediatric patients with cardiac problems.

• The management of immunocompromised patients.

• Sedatives and hypnotics.

• Dental trauma.

• Emergency drugs.

• Fluorides and fluoride supplements.
Mass-Producing the Individual: Mary C. Jarrett, Elmer E. Southard, and the Industrial Origins of Psychiatric Social Work
Authors: Gabriel Joseph M
Published: September 2005

SUMMARY : This article examines the origins of psychiatric social work in the United States between 1912 and 1930. It argues that the establishment of the field needs to be understood in terms of Mary C. Jarrett and Elmer E. Southard's efforts to apply psychiatric techniques to the mental health problems of industrial employees. It further argues that Jarrett and Southard worked to develop a treatment approach to the mental health problems of industrial workers that they termed "individualization," and that despite their assumptions about the future of psychiatric social work the field was never established as an important part of industrial management.
Taking a Medical History in Childhood Illness: Representations of Parents in Pediatric Texts since 1850
Authors: Gillis Jonathan
Published: September 2005

SUMMARY: The pediatric clinical encounter is initiated when a sick child is pre- sented to a physician and the physician takes a history from the parent. This article casts the physician's construction of that encounter in a central role in the history of the theory and practice of children's medicine. The focus is on what physicians have written about the conduct of such encounters, and specifically on their attitudes to and instructions for the taking of a history. This analysis reveals that medical writings on the taking of a medical history provide a window into how pediatric writers wanted their discipline to be conducted, what they identified as the normative principles of pediatric practice, and how they portrayed parents. The texts show a striking continuity in the ambivalence expressed by practitioner authors about the parental role in the clinical assessment of sick children. What emerges is both a regret that the physician must be dependent on parental history for clinical assessment, and a message that any doctor dealing with children should both value the parental history and distrust it. Because history taking is a fundamental, core medical activity, these normative principles and representations of parents were dispersed easily, widely, and unconsciously within pediatric practice. They also provide a link to the wider contexts of physicians' involvement in child rearing, the influence of psychiatry, and the fundamental gender structure of the clinical encounter.
Pinel in the Maghreb: Liberation, Confinement, and Psychiatric Reform in French North Africa
Authors: Keller Richard C. (Richard Charles)
Published: September 2005

For early twentieth century French psychiatrists, the colonies of Algeria, Tunisia, and Morocco appeared as crucial sites for innovation. Citing Pinel's liberation of the insane during the French Revolution as a precedent, colonial psychiatrists preached of their capacity to advance France's "civilizing mission" by delivering the insane from their suffering. Yet colonial renovation programs also drew them to scrutinize the failings of their own common practices. Psychiatrists saw their field in a state of crisis, marked by overcrowded asylums and outdated therapeutic concepts. Attempts to modernize colonial terrains thus also aimed at re creating a discipline that had fallen into decline.
Glimpses of a Hidden Burden: Hydatid Disease in Eighteenth-Century Scotland
Authors: Risse Guenter B.
Published: September 2005

SUMMARY : "Hydatids" or watery cysts have been observed in animals and humans since ancient times, giving rise to frequent speculation as to their nature and origin. This essay focuses on an extremely rare clinical case managed at the Edinburgh Infirmary in 1785 by James Gregory, professor of the theory of medicine. Following the death of the patient, an autopsy disclosed lesions characteristic of a condition eventually labeled "echinococcosis of the liver," today one of the most common parasitic diseases in sheep raising regions of the world. The essay reviews the obscure nature of this endemic disease in Gregory's time, and the difficulties confronting scientists and clinicians keen to unravel its secrets.
The Making of "Truth Serum," 1920-1940
Authors: Winter Alison
Published: September 2005

This essay reconstructs a social and cultural history of "truth serum" in America during the 1920s and 1930s, identifying the intellectual ingredients of the idea of a physiological "truth technique," and examining why it seemed to meet an urgent need. It argues that truth serum had the patina of modern science but produced a phenomenon that could be understood and evaluated by everyman. It therefore offered the public a technique with the benefits of expertise but without its attendant costs to lay authority. The paper also argues that truth serum helped develop an account of memory as a permanent record of experience, accessible through altered states of mind. This view contributed to the production of a public understanding of memory that both diverged from previous claims about memory and recall, and ran counter to the direction of current psychological research. It thus helped lay the groundwork for claims about memory permanence and scientific recall techniques later in the twentieth century.
Transnational Maleness: The Italian Immigrant in Hell Drivers
Authors: Girelli Elisabetta
Published: September 2005

This essay explores the representation and function of the Italian man in the 1950s "tough-guy" film Hell Drivers, focusing on the dynamic interaction between Italianness and Britishness in the film's construction of a new antihero.