bluuebunny/crossref_metadata_2025 huggingface dataset:
An Application of Physics-Based and Artificial Neural Networks-Based Hybrid Temperature Prediction Schemes in a Hot Strip Mill
Authors: Geerdes Wouter M. , Alvarado Miguel Ángel Torres , Cabrera-Ríos Mauricio , Cavazos Alberto
Published: May 2008

In hot strip mills, estimation of rolling variables is of crucial importance to setting up the finishing mill and meeting dimensional control requirements. although the use of physics-based models is preferred by the specialists to keep the fundamental knowledge of the underlying phenomena, many times a purely empirical model, such as an artificial neural network, will provide better predictions although at the cost of losing such fundamental knowledge. This paper presents the application of physics-based and artificial neural networks-based hybrid models for scale breaker entry temperature prediction in a real hot strip mill. The idea behind combining these two types of models is to capitalize in what are often portrayed as their main advantages: (i) keeping the physics knowledge of the process and (ii) providing better predictions. Temperature prediction schemes with different hybrid levels between a pure heat transfer model and an artificial neural network alone were evaluated and compared showing promising results in this case study. Using an artificial neural network together with the heat transfer model helped to achieve better temperature predictions than using the heat transfer model alone in every instance, thereby proving the hybrid schemes attractive to the industry. In this work, three different hybrid schemes combining the knowledge imbedded in a heat transfer model and the prediction capabilities of an artificial neural network in temperature prediction in a hot strip mill were tried. The hybrid models came out quite competitive in this case study. The results support the use of empirical models to foster the prediction ability of physics-based models; that is, they make the case for their joint use as opposed to their exclusive use.
On Eccentric Tube Nosing
Authors: Nemat-Alla Mahmoud
Published: May 2008

Joining two tubes of different diameters has important concerns in many industries and engineering applications. An eccentric reducer is often used in such applications. Therefore, a simple and easy technique for manufacturing an eccentric reducer is of much importance. The simplest technique for producing the eccentric reducers is the tube nosing through eccentric conical dies. In this paper the finite element simulation is used to investigate the eccentric nosing of circular tubes through an eccentric conical die. Simulation is performed to investigate the plastic deformations of the deformed tube and all the possible modes of failure during the eccentric nosing process. Identification of unfavorable modes of failure in the tube nosing process lead to design modification guidelines, design of preform, and the die shape, for the eccentric nosing process. The results obtained confirmed that the modified design of the tube blank not only improves the quality of the nosed-tube product but also reduces nosing load and improves the limiting nosing ratio. Comparison with the experimental results shows that the nosing load and the modes of failure are successfully predicted by the finite element simulation. Also, a preform design for the tube blank that can produce an eccentric reducer with collar end that did not need a trimming process is introduced.
Nonlinear Feed Effect in Machining Chatter Analysis
Authors: Landers Robert G. , Ulsoy A. Galip
Published: May 2008

Regenerative chatter is a major limitation to the productivity and quality of machining operations due to the excessive rate of tool wear and scrap parts which are produced. Machining chatter analysis techniques examine the stability of the closed-loop model (force process and machine tool-part structure) of the machining operation to determine the stable process parameter space. Almost all chatter analysis techniques assume a linear force process and develop stability lobe diagrams (i.e., plots of the stable and unstable regions in the process parameter space) for a specific feed. It is well known that machining force processes inherently contain a nonlinear relationship between the force and the feed, which is typically described by a power law. In this paper, the linear chatter analysis technique developed by Budak and Altintas is extended to account for the force-feed nonlinearity. The analysis provides insight into the effect feed has on chatter in machining operations. Also, by directly including the force-feed nonlinearity in the chatter analysis, the need to calibrate the force process model at different feeds is alleviated. The analysis is developed for turning and face milling operations and is validated via time domain simulations for both operations and by experiments for a face milling operation. The analyses show excellent agreement with both the time domain simulations and the experiments. Further, several end milling experiments were conducted that illustrate the nonlinear effect feed has on chatter in machining operations.
Minimum Move-Vibration Control for Flexible Structures
Authors: Dhanda Abhishek , Franklin Gene
Published: May 2008

In the rest-to-rest motion of a flexible structure with limited torque or force, it is sometimes important to control the vibrations during the move trajectory as well as at the final time. In order to achieve this control, the duration of the move must be set to be longer than the theoretical minimum time. In this paper, three definitions of trajectory vibration performance are given and a new method for input design is described, which is based on switched control. An analytical expression is obtained for the solution for lightly damped fourth-order systems, which enables a very efficient control implementation of approximately time-optimal moves. The switched control approach is generalized for presenting simplified approximate solutions for the tracking problem and other optimal control problems with singular arcs.
Design, Modeling, and Motion Control of the Noncircular Turning Process for Camshaft Machining
Authors: Tsao Tsu-Chin , Sun Zongxuan , Hanson Reed D. , Babinski Alexanda
Published: May 2008

This paper presents the design, modeling, and motion control of the noncircular turning process for camshaft machining. The cam profile tracking performance requirements are first characterized to meet industry standards. Based on these requirements, a unique test fixture using state-of-the-art actuation and sensing technologies is designed for the noncircular turning process. Modeling of the electrohydraulic servo valve, actuator, and sensors is conducted based on their frequency responses. Digital motion control that achieves asymptotic cam profile tracking while maintaining system robust stability is designed and implemented on the turning test fixture. Spindle speed can be chosen depending on the required profile tracking accuracy with higher speed rendering higher machining rate for rough turning and lower speed rendering higher accuracy for finish turning. Experimental results of turning a variety of cam profiles show that the tracking error is less than 30μm for spindle speed at 300rpm and is less than 60μm for spindle speed at 600rpm or 1200rpm.
An Analysis Framework for Evaluating Dropout Compensation Strategies in Wireless Servo Systems
Authors: Kawka Paul A. , Alleyne Andrew G.
Published: May 2008

This paper presents an approach for analyzing the performance of dropout compensation strategies for linear servo control systems operating over communication channels with losses. A loss of communication causes the normal control action to be replaced by an appropriately designed dropout compensation action. A linear matrix inequality based approach is given for examining H∞ and/or H2 performance of wireless feedback systems using dropout compensation where we assume a two-state Markov model for the communication network. To illustrate the analysis method, we introduce two specific data dropout compensation schemes: zero order hold and estimation. These two schemes are compared in simulation and experiment to validate the effectiveness of the performance analysis.
Process Feedback Control of the Noncircular Turning Process for Camshaft Machining
Authors: Sun Zongxuan , Tsao Tsu-Chin
Published: May 2008

This paper presents a frequency domain learning control scheme for a class of nonlinear systems and its application to the process feedback control of the noncircular turning process for camshaft machining. In frequency domain, periodic signals are represented by the Fourier expansions that are nonzero only at discrete frequency points. An input dependent system matrix can be used to describe the input-output relationship of a class of nonlinear systems with periodic input and output signals. A learning controller is designed based on the system matrix and the bound of unmodeled dynamics. Conditions to achieve asymptotic stability and tracking performance are derived. To further improve system robustness, a low pass filter is used to turn off the learning scheme at high frequencies. The learning control scheme is then applied to the process feedback control of camshaft machining using the noncircular turning process. A two level control structure is adopted. The first level is servo control that ensures precise tool slide motion. The second level is frequency domain learning control that compensates machined profile errors due to the effects of tool/workpiece geometry, tool wears, machine deformations, and spindle runout errors. Relationship between the servo control and learning control is discussed. Implementation of the process feedback control on a steel camshaft turning demonstrates improvement of the maximum cam profile errors from 80μm to within 20μm in five iterations.
Role of oxygen impurities in etching of silicon by atomic hydrogen
Authors: Veprek Stan , Wang Chunlin , Veprek-Heijman Maritza G. J.
Published: May 2008

In a pure-hydrogen glow discharge plasma, the etch rate of silicon increases with increasing temperature up to about ≥1100 Å/s at 60–80 °C and, upon a further increase of the temperature, etch rate strongly decreases, showing Arrhenius-like dependence with negative apparent activation energy of −1.5 kcal/mol. When the Si sample is at the floating potential, oxygen impurities of ≥10 at. ppm strongly decrease the etch rate. At more than 70 ppm of oxygen, the etching stops. Oxygen adsorbed on the Si surface can be removed by ion bombardment when negative potential is applied to the Si sample and the Si is then etched chemically by H atoms. The etching by atomic hydrogen is isotropic in an oxygen-free system. A controllable addition of a few ppm of oxygen in combination with negative bias of the Si sample results in highly anisotropic etching with thin oxide acting as side-wall passivation.
Experimental study of Cr∕Sc multilayer mirrors for the nitrogen Kα-emission line
Authors: Hardouin Aurélie , Delmotte Franck , Ravet Marie Françoise , Bridou Françoise , Jerome Arnaud , Varniere Françoise , Montcalm Claude , Hedacq Sébastien , Gullikson Eric , Aubert Pascal
Published: May 2008

The authors present an experimental study of Cr∕Sc multilayer mirrors optimized for the detection of the nitrogen Kα-emission line (λ=3.16nm) at a grazing incidence around 23°, for electron probe microanalysis applications. The multilayers were deposited onto silicon substrates using a dc magnetron sputtering system. They were characterized with grazing incidence copper Kα x-ray reflectometry and atomic force microscopy, as well as with at-wavelength reflectometry using synchrotron radiation. These various characterization methods pointed out that the interfacial roughness of these multilayers increases drastically with the number of bilayers. Growth parameters were then optimized, and it is shown that the structure and reflectivity of such multilayers can be considerably improved by optimizing the sputter gas pressure during the deposition process. Reflectivity higher than 37% were measured at 22.3° grazing angle for the nitrogen Kα-emission line.
On the gas species dependence of Pirani vacuum gauges
Authors: Jousten Karl
Published: May 2008

The dependence of the readings of four different Pirani vacuum gauges on nine different gas species was investigated. It was found that the gas species dependence varied from gauge to gauge so that in general only an approximate correction factor for a specific gas species can be given for this type of vacuum gauge. A Pirani gauge produced by microstructuring methods showed a broader measurement range than conventionally produced gauges. By comparing experimental with theoretical data, it was possible to give upper limits of the thermal accommodation coefficients of the nine gas species on the technical surfaces of oxidized tungsten and silicon within the gauges.
Development of a compact vacuum- and hydrogen-annealing machine for surface transformation of silicon and its applications to micro-optical devices
Authors: Kanamori Yoshiaki , Douzono Kenichi , Fujihira Shinya , Hane Kazuhiro
Published: May 2008

The authors developed a compact vacuum- and hydrogen-annealing machine to transform and smooth silicon surfaces for silicon microoptical devices. Two kinds of configurations, named sealing type and flowing type, were evaluated. The sealing type configuration was designed to anneal a sample inside a H2 gas environment contained within a quartz tube. On the other hand, the flowing type configuration was designed to anneal the sample using a flowing H2 gas environment. The machine sizes were 1.6 m in width, 0.55 m in depth, and 1.3 m in height. Control ranges of temperature and pressure were between 20 °C and 1300 °C and between 4.1×10−7 and 760 Torr, respectively. Using the flowing type configuration, the samples were successfully smoothed at conditions of H2 partial pressure of 50 Torr, temperature of 1230 °C, H2 gas flow rate of 1 slm, and annealing time of 11 min. By transforming the surface, microlenslike structures with the size of the order of several micrometers and a sinusoidal grating were also fabricated from cylindrical pillars and a lamellar grating, respectively. The authors measured the surface roughness on the samples before and after annealing, and it was obviously decreased after annealing for all of the measured samples.
Multiparameter investigation of the sputtering behavior of Ag∕Cu Alloys for low energy argon ion bombardment
Authors: Pierson K. W. , Hawes C. D. , Kollwitz J. T. , Padrón A. S.
Published: May 2008

The sputtering behavior of Ag∕Cu alloys due to low energy (100–1500eV) Ar+ bombardment as a function of component composition, sample temperature, ion current density, ion dose, and ion energy has been completed. The results indicate that the surface topography development is a strong function of temperature and depends to a lesser extent on ion energy, ion dose, and ion current density. The surface at low temperature coupled with low ion dose and/or low ion current density is flat and faceted with widely dispersed large cones. As the temperature is raised, the rate of Ag surface diffusion increases faster than that of Cu and Ag begins to coat the Cu grains thereby, decreasing the subsequent erosion of the Cu. Selective sputtering of the higher yield Ag and continuous Ag diffusion toward the surface results in a decrease in the Ag concentration in the near surface region as measured by energy dispersive spectroscopy. Auger electron spectroscopy (AES) depth profiles indicate significant diffusion of both Cu and Ag when the electron beam was used in spot mode. Angular distributions of sputtered material indicate that Ag is ejected more preferentially at large angles to the surface normal. The total sputter yield is a function of temperature, ion energy, and dose. These effects are related to the growth of surface topography and the subsequent recapture of ejected material on to the sides of surface features. A method of increasing the thermal conductivity between the sample and holder using graphite colloid was found to affect the surface topography growth and AES profiles. The results of these experiments have implications for depth profiling of multicomponent metallic alloys.
Finite element modeling and experimental validation of the sealing mechanism of the ConFlat® joint
Authors: Lutkiewicz P. , Rathjen Ch.
Published: May 2008

The sealing mechanism of flat copper gaskets and ConFlat (CF) flanges is studied. Finite element (FE) modeling was used and the results were validated through experiments. Only a part of the CF flange knife surface contributes to the sealing. A bilinear character of compression force and displacement evolution was numerically and experimentally identified and has been described by a phenomenological formula. The influence of the flange collar and gasket material properties on the sealing mechanism was studied. The plastic strain field produced by the knife in the gasket was compared to microhardness tests. The possibility of crack propagation was studied because of large plastic deformation (FE results) near the knife tip.
Evolution of epitaxial Ta2O5 and Ta2O films during thermal oxidation of epitaxial tantalum films on sapphire substrates
Authors: Gnanarajan S. , Lam S. K. H.
Published: May 2008

The evolution of the tantalum oxide structure during low pressure thermal oxidation of epitaxial Ta films on a sapphire substrate was investigated. Thin Ta films were deposited using magnetron sputtering on sapphire substrates at a temperature of 700°C. Thermal oxidation of these films in oxygen at a pressure of 1.0Pa at a temperature of 700°C produced epitaxial Ta2O and Ta2O5 films as determined by x-ray diffraction techniques. The epitaxial Ta2O film had a cubic structure with a (101) plane oriented in the substrate plane. The epitaxial Ta2O5 films had a twinned orthorhombic structure with a (201) plane oriented in the substrate plane.
IONIZATION BY QUANTIZED ELECTROMAGNETIC FIELDS: THE PHOTOELECTRIC EFFECT
Authors: ZENK HERIBERT
Published: May 2008

In this paper, we explain the photoelectric effect in a variant of the standard model of non relativistic quantum electrodynamics, which is in some aspects more closely related to the physical picture, than the one studied in [5]. Now, we can apply our results to an electron with more than one bound state and to a larger class of electron-photon interactions. We will specify a situation, where the second order of ionization probability is a weighted sum of single photon terms. Furthermore, we will see that Einstein's equality [Formula: see text] for the maximal kinetic energy E kin of the electron, energy hν of the photon and ionization gap △E is the crucial condition, for these single photon terms to be nonzero.
SELF-ORGANIZING BIRTH-AND-DEATH STOCHASTIC SYSTEMS IN CONTINUUM
Authors: KONDRATIEV YURI , MINLOS ROBERT , ZHIZHINA ELENA
Published: May 2008

We consider birth-and-death stochastic particle systems in continuum which are under a self-regulation mechanism controlling configurations of particles via a pairwise interaction between them. The latter is reflected in a potential perturbation of the free generator. We show that the ground state renormalization scheme in the considered model leads to an invariant measure, a renormalized generator and resulting equilibrium birth-and-death stochastic dynamics for the system. The proof is based on the Gibbs-type representation for related path space measure. This measure has OS-positivity property and is constructed via the cluster expansion method.
Mercaptoacetate inhibition of fatty acid β-oxidation attenuates the oral acceptance of fat in BALB/c mice
Authors: Matsumura Shigenobu , Saitou Katsuyoshi , Miyaki Takashi , Yoneda Takeshi , Mizushige Takafumi , Eguchi Ai , Shibakusa Tetsuro , Manabe Yasuko , Tsuzuki Satoshi , Inoue Kazuo , Fushiki Tohru
Published: May 2008

We investigated the effect of β-oxidation inhibition on the fat ingestive behavior of BALB/c mice. Intraperitoneal administration to mice of mercaptoacetate, an inhibitor of fatty acid oxidation, significantly suppressed intake of corn oil but not intake of sucrose solution or laboratory chow. To further examine the effect of mercaptoacetate on the acceptability of corn oil in the oral cavity, we examined short-term licking behavior. Mercaptoacetate significantly and specifically decreased the number of licks of corn oil within a 60-s period but did not affect those of a sucrose solution, a monosodium glutamate solution, or mineral oil. In contrast, the administration of 2-deoxyglucose, an inhibitor of glucose metabolism, did not affect the intake or short-term licking counts of any of the tasted solutions. These findings suggest that fat metabolism is involved in the mechanism underlying the oral acceptance of fat as an energy source.
Grading of Classical Testicular Microlithiasis Has No Effect on the Prevalence of Associated Testicular Tumors
Authors: Sanli Oner , Kadioglu Alev , Atar Murat , Acar Omer , Nane Isme , Kadioglu Ates
Published: May 2008

Aim: To evaluate the role of further grading of classical testicular microlithiasis (CTM) on the prevalence of associated testicular tumors. Methods: Patients diagnosed with CTM using scrotal ultrasound over a 5-year period from a referral radiology clinic were included in this study. Patients with CTM were categorized as group 1 (grade I; 5–10 microliths/image), group 2 (grade II 10–20 microliths/image), and group 3 (grade III > 20 microliths/image). Other pathological findings were also recorded. The prevalence of testicular cancer was compared statistically between groups using the χ2 test. Results: Seventy-eight of 4,310 (1.8%) patients were found to have CTM. Of these, 17 (21.7%) had ultrasonographically detected testicular cancer. In patients without CTM (n = 4,232), 58 (1.1%) testicular cancers were found. This accounted to a 19.7-fold increase in the detection rate of testicular cancer in patients with CTM compared to patients without CTM. The rates of testicular cancer detected in groups 2 and 3 were 25 (6/24) and 26.6% (4/15), respectively (p > 0.05), while it was 17.9% (7/39) in group 1. Conclusions: CTM is an uncommon incidental finding in patients undergoing testicular ultrasonography, and grading of CTM plays no role in the prevalence of testicular cancer.
Decreased Incidence of Appendix Testis in Cryptorchidism with Intraoperative Survey
Authors: Józsa Tamás , Csízy István , Kutasy Balázs , Cserni Tamás , Flaskó Tibor
Published: May 2008

Objective: Several authors have investigated the background of the process of testicular descent, but the role of the appendix testis has not been studied. The human appendix testis was found to express both estrogen and androgen receptors. We determined and compared the occurrence of testicular appendices intraoperatively in descended and undescended testes. Methods: The number of appendix testis was evaluated retrospectively in 208 boys who underwent uni- or bilateral orchiopexy, hydrocele or hernia repair and the testis was visible during operation. Results: The incidence of appendix testis was 76% (78 in 103) in descended and 24% (30 in 125) in undescended testes. Mean age at orchiopexy was lower in patients without appendix testis (39 months) compared to those patients who were found with appendix (61 months). Conclusion: The incidence of appendix testis was significantly lower (p < 0.05) in undescended testes, suggesting that the appendix testis might play a role in the process of testicular descent.
XELOX Followed by XELIRI or the Reverse Sequence in Advanced Colorectal Cancer
Authors: Sakar B. , Gumus M. , Basaran M. , Argon A. , Ustuner Z. , Ustaoglu M.A. , Saglam S. , Guney N. , Tenekeci A.N. , Aykan N.F.
Published: May 2008

Background: Capecitabine has demonstrated high efficacy as first-line treatment for metastatic colorectal cancer (mCRC). In this non-randomized pilot study, we investigated the efficacy and safety of sequentially administered XELOX and XELIRI regimens or the reverse sequence in patients with advanced colorectal cancer. Patients and Methods: Entry criteria were histologically confirmed mCRC, ECOG performance status (PS) ≤2 and adequate bone marrow, renal and hepatic function. All patients consecutively received XELOX followed by XELIRI at disease progression or vice versa. Results: In multivariate analysis, independent prognostic factors with worse overall survival were: lower PS (p = 0.0001), multiple metastatic sites (p = 0.016) and high tumor grade. Higher serum levels of alkaline phosphatase and worse ECOG PS were associated with a shorter progression-free survival. Grade 3/4 mucositis, nausea/vomiting, grade 3/4 alopecia and grade 3 diarrhea were more frequent with XELIRI, whereas major toxicity events with XELOX were grade 3 neutropenia, thrombocytopenia and grade 2/3 neurotoxicity. Conclusion: Capecitabine appears to be an acceptable alternative to continuous-infusion fluorouracil (FU)/leucovorin (LV) in combination therapy and offers an effective, but more convenient alternative to continuous infusion FU/LV in the first-line treatment of patients with mCRC.
Endogenous retroviral LTR DNA sequences as markers for individual human chromosomes
Authors: Nakamura N. , Sugino H. , Takahara K. , Jin C. , Fukushige S. , Matsubara K.
Published: May 2008

The human genome carries multiple copies of sequences related to endogenous retroviral genomes that include long terminal repeat (LTR) sequences. We used the LTR of one such viral genome, called HERV-A, as a probe in Southern analysis to examine the distribution profiles of the hybridizing DNA in the genomes of twelve human × rodent hybrid cell lines carrying one or a few human chromosomes, and in the DNA samples prepared from six sorted, individual chromosomes. The HERV-A sequence was found to be widely distributed among different chromosomes and the Southern patterns for chromosomes 5, the X, and the Y, each obtained in duplicate from independently prepared cell lines or sorted chromosomes, were matched. Chromosome-specific Southern profiles can be used to monitor chromosomes in hybrid cells or to characterize chromosome aberrations, such as deletions.
The gene for human growth hormone-releasing factor (GHRF) maps to or near chromosome 20p12
Authors: Rao V.V.N.G. , Löffler C. , Schnittger S. , Hansmann I.
Published: May 2008

Growth hormone-releasing factor (GHRF), a hypothalamic releasing factor also named somatocrinin, influences the secretion and synthesis of growth hormone. Human GHRF is encoded by a single gene which was assigned to chromosome 20 by dot-blot analysis of DNA from dual laser sorted chromosomes. Using a radioactive cDNA probe, we localized the GHRF gene to chromosome 20p12 or near band 20p12.
Assignment of the porcine aminopeptidase N (PEPN) gene to chromosome 7cen→q21
Authors: Poulsen P.H. , Thomsen P.D. , Olsen J.
Published: May 2008

The porcine aminopeptidase N (PEPN) gene was shown to be syntenic with the porcine major histocompatibility complex (SLA) using Southern blot analysis of a pig × mouse hybrid cell panel. Regional localization of the PEPN gene to 7cen→q21 was performed by in situ hybridization. The results suggest that synteny of the genes for mannose phosphate isomerase and PEPN is conserved in pig and man.
Achiasmatic giant sex chromosomes in the vole Microtus cabrerae(Rodentia, Microtidae)
Authors: Jiménez R. , Carnero A. , Burgos M. , Sánchez A. , Díaz de la Guardia R.
Published: May 2008

Conventional and microspread preparations of Microtus cabrerae spermatocytes were made to investigate the chromosomes of this species. Three different types of Y chromosomes, varying in size of the heterochromatic block, were observed; they were alike, however, in regard to synapsis, which was consistently absent. Our results suggest that the heterochromatic blocks are not involved in the lack of synapsis and that asynapsis is a cytological feature common to all species of the family Microtidae. In addition, the co-aligned configuration of the ends of the sex-chromosome axes of this species and the lack of silver-stainable threads or filaments connecting them suggest the existence of two mechanisms for association of the sex chromosomes during prophase I and metaphase I: attachment of the ends of both sex chromosome axes to the nuclear envelope and heterochromatin “stickiness.”
Longitudinal differentiation of the human Yq heterochromatin as revealed by the restriction enzyme TaqI
Authors: Fernández-Piqueras J. , Ludefia P. , De Cabo S.F. , Velázquez M. , Sentís C.
Published: May 2008

The restriction endonuclease TaqI cleaves DNA at TCGA sites which are very common in human satellite DNAs. However, this enzyme was not used successfully up to now to digest constitutive heterochromatin of human chromosomes, where those highly repetitive DNAs are preferentially located. In this work, we show that TaqI is able to cut and extract DNA from the major heterochromatic regions on chromosomes 1, 9, 15, and 16 which appear as unstained gaps. Yq heterochromatin displays moderate digestion along its entire length but a middle region can be distinguished which is usually more affected. Complete digestion of Yq heterochromatin can be achieved when this block has been previously undercondensed by treating cell cultures with the cytidine analog, 5-azacytidine. Thus, it may be deduced that some factors related to chromatin organization might be involved in the action of TaqI. These results come to reinforce previous data about heterogeneity of Yq heterochromatin, and allow us to subdivide it into three different regions according to their differential response to Taql digestion.
Isolation and regional localization of 25 anonymous DNA probes on a chromosome 13 hybrid panel
Authors: Houwen R.H.J. , Pautler S.E. , Barwell J.A. , Arden K. , Buchanan J.A. , James C.D. , Cavenee W.K. , Buys C.H.C.M. , Cowell J.K. , Cox D.W.
Published: May 2008

Clones were isolated from two flow-sorted chromosome 13 libraries. Twenty-five clones were localized to various regions of chromosome 13, using a well-characterized panel of rodent × human hybrid cell lines. Eight DNA markers were localized to 13q14.2→q22, where the gene for Wilson disease, a recessive disorder of copper metabolism, was previously assigned. The new markers will be useful for the diagnosis of pre-symptomatic sibs of Wilson disease patients. We isolated six DNA clones proximal to the retinoblastoma gene, a region in which a translocation associated with rhabdomyosarcoma has been observed. Probes for both of these regions will be useful for the cloning of the genes involved in these diseases.
Oligonucleotide-primed in situ DNA synthesis (PRINS): a method for chromosome mapping, banding, and investigation of sequence organization
Authors: Gosden J. , Hanratty D. , Starling J. , Fantes J. , Mitchell A. , Porteous D.
Published: May 2008

Oligonucleotides were annealed to complementary sequences in fixed human metaphase chromosomes and extended with DNA polymerase. The newly synthesized fragments were labeled by incorporating bio-11-dUTP instead of TTP, and the sites of synthesis were detected by immunocytochemistry, using fluorochromes as the reporter molecules. We have obtained clear localization with oligonucleotides from alphoid (centromeric sequences), simple sequence (satellite) DNAs, a variety of Alu-dispersed repeated sequences, and oligonucleotides derived from the Tetrahymena and Trypanosoma telomere-specific sequences. The simple sequence and alphoid oligonucleotides gave results at least comparable to those obtained using the whole molecule as a probe for in situ hybridiza tion, whereas the Alu oligonucleotides produced a diversity of results which depended on the absolute length and location of the oligonucleotide within the Alu sequence. The telomere-specific oligomers also produced a variety of results. The G-rich Trypanosoma oligomer and its complementary C-rich sequence produced strong telomeric signals and some interstitial signals on mouse chromosomes, but only weak telomeric signals on human chromosomes. The G-rich Tetrahymena oligomer produced detectable telomeric signals on human chromosomes. The technique appears to be a valuable extension of present tools for mapping and examining the organization of DNA sequences within chromosomes.
Rapid localization of membrane skeletal protein 4.1 (EL1) to human chromosome 1p33→p34.2 by nonradioactive in situ hybridization
Authors: Tang C.-J.C. , Tang T.K.
Published: May 2008

Hereditary elliptocytosis (HE) is a heterogeneous group of red-cell disorders. One class of HE patients was shown to have a mutated erythrocyte membrane skeletal protein 4.1 gene. We have recently shown that human protein 4.1 contains multiple isoforms with novel sizes, functions, and tissue-specific expression. Here, we report the subregional localization of this gene to human chromosome 1p33→p34.2, based on the fractional length, by nonradioactive in situ hybridization.
The most frequently lost allelic site in human renal cell carcinoma (D3F15S2) on the short arm of chromosome 3 has homologous sequences on rat chromosome 8
Authors: Erlandsson R. , Szpirer J. , Islam M.Q. , Boldog F. , Klein G. , Ingvarsson S.
Published: May 2008

It has previously been shown that human chromosome 3 has banding homology to rat chromosome 8. We have previously isolated a cDNA from the D3F15S2 region and des ignated the gene as RIK. In the present study, we localized the homolog of this gene to rat chromosome 8.
Localization of the gene encoding insulin-degrading enzyme to human chromosome 10, bands q23→q25
Authors: Espinosa III R. , Lemons R.S. , Perlman R.K. , Kuo W.-L. , Rosner M.R. , Le Beau M.M.
Published: May 2008

Insulin-degrading enzyme (IDE) is a cytosolic proteinase involved in the cellular processing of insulin. Using somatic cell hybrid analysis and in situ chromosomal hybridization, we have localized the gene encoding IDE to human chromosome 10, bands q23→q25. The murine Ide gene was previously mapped to Chromosome 19; together, these results suggest that the IDE gene is a member of a conserved syntenic group on human chromosome 10, bands q23→q25 and mouse Chromosome 19.
Synapsis and obligate recombination between the sex chromosomes of male laboratory mice carrying the Y* rearrangement
Authors: Hale D.W. , Hunt P.A. , Tucker P.K. , Eicher E.M.
Published: May 2008

The synaptic and recombinational behavior of the sex chromosomes in male laboratory mice carrying the Y* rearrangement was analyzed by light and electron microscopy. Examination of zygotene and pachytene X-Y* configurations revealed a surprising paucity of the staggered pairing configuration predicted from the distal position of the X pseudoautosomal region and the subcentromeric position of the Y* pseudoautosomal region. When paired at pachynema, the X and Y* chromosomes usually assumed configurations similar to those of typical sex bivalents from normal male laboratory mice. The X and Y* chromosomes were present as univalents in more than half of the early- and mid-pachytene nuclei, presumably as a result of steric difficulties associated with homologous alignment of the pseudoautosomal regions. When paired at diakinesis and metaphase I, the X and Y* chromosomes exhibited an asymmetrical chiasmatic association indicative of recombination within the staggered synaptic configuration. Both pairing disruption and recombinational failure apparently contribute to diakinesis/metaphase I sex-chromosome univalency, as most cells at these stages possessed X and Y* univalents lacking evidence of prior recombination. Recombinant X or Y* chromosomes were detected in all metaphase II complements examined, thus substantiating the hypothesis that X-Y recombination is a prerequisite for the normal progression of male meiosis.
Microtubule-associated proteins during mouse spermatogenesis: localization of a protein immunologically related to brain MAP1B protein in the synaptonemal complex
Authors: Gil-Alberdi L. , Del Mazo J.
Published: May 2008

Monospecific polyclonal antibodies against MAP1A protein and an immunologically related brain MAP1B polypeptide were used to visualize mouse synaptonemal complexes (SCs) with immunofluorescence microscopy. Anti-MAPI A antibody recognized SCs uniformly. However, when anti-MAP1B antibody was used, a dashed pattern of staining was observed along the SCs in both autosomes and pachytene XY bivalents. After purification of SCs, immunoblots of the electrophoresed proteins revealed a polypeptide of 220 kDal, which was recognized by anti-MAP1B antibody, and two proteins of 180 kDal and 160 kDal, which were recognized by anti-MAP1A antibody. High-molecular-weight polypeptides immunologically related to microtubule-associated proteins were localized in the cell nucleus. The function of these nuclear proteins is unknown. The distribution of fluorescent signal corresponding to the 220-kDal protein during meiosis and spermiogenesis and its localization in the nuclear matrix suggest the participation of preexisting nucleoskeletal proteins in the molecular organization of the SC and its dynamics during meiotic prophase.
Chromosomal localization of the human gene for palmitoyl-CoA ligase (FACL1)
Authors: Stanczak H. , Stanczak J.J. , Singh I.
Published: May 2008

We have localized the gene (FACL1) encoding human long chain fatty acid-coenzyme A ligase, E.C.6.2.1.3, also known as palmitoyl-CoA ligase. Using in-situ hybridization, we have mapped this gene to chromosome region 3ql 3 in the human karyotype.
Regional localization of the human platelet-derived endothelial cell growth factor (ECGF1) gene to chromosome 22q13
Authors: Stenman G. , Sahlin P. , Dumanski JP. , Hagiwara K. , Ishikawa F. , Miyazono K. , Collins VP. , Heldin C.-H.
Published: May 2008

Using in situ hybridization and a panel of human × rodent somatic cell hybrids, which discriminates between four different regions of human chromosome 22, we have localized the gene for human platelet-derived endothelial cell growth factor (ECGFl) to 22q13, placing ECGFl distal to the PDGFB locus at 22q12.3→q13.1.
Cytogenetics and karyosystematics of South American oryzomyine rodents (Cricetidae: Sigmodontinae)
Authors: Barros M.A. , Reig O.A. , Perez-Zapata A.
Published: May 2008

Bone marrow chromosomes were studied in South American water rats of the genus Nectomys from Venezuela, Trinidad, and Argentina. Specimens of N. squamipes from western and southern Venezuela showed a 2n = 52–53 karyotype, whereas a 2n = 56–57 karyotype was found in specimens from northeastern Argentina. In both cases, odd karyotypes can be explained by the presence of a supernumerary chromosome. In contrast, water rats from northeastern Venezuela and Trinidad showed a strikingly reduced 2n = 16–17 polymorphic chromosome complement. Six different karyomorphs were found among the latter, which may have resulted from a combination of pericentric inversions in two pairs of autosomes and a cen-tromeric fusion in another autosomal pair. It is proposed that the new 2n = 16–17 cytotypes belong to a species of its own, for which the name N. palmipes is suggested.
Assignment of the chromosomal locus of the human 30-kDal Rh (Rhesus) blood group-antigen-related protein (Rh30A) to chromosome region 1p36.13→p34
Authors: MacGeoch C. , Mitchell C.J. , Carritt B. , Avent N.D. , Ridgwell K. , Tanner M.J.A. , Spurr N.K.
Published: May 2008

Using a panel of somatic cell hybrids, we have localised the 30-kDal Rhesus blood group-antigen-related protein to human chromosome 1 in the region p36.13→p34. This confirms the localisation of this protein described previously using cytogenetic and linkage analyses.
Regional localization of the owl monkey MYB and OMLA gene loci
Authors: Ma N.S-F.
Published: May 2008

Regional mapping of the MYB and OMLA gene loci to their respective sites on owl monkey chromosome 9q of karyotype VI support the proposed homology of this primate
Karyology of the Savi pine vole, Microtus savii (De Sélys-Longchamps, 1838) (Rodentia, Arvicolidae): G-, C-, DA/DAPI-, and AluI-bands
Authors: Galleni L. , Stanyon R. , Tellini A. , Giordano G. , Santini L.
Published: May 2008

Specimens of the Savi pine vole (Microtus savii) were collected from three localities in central (Pisa and Viterbo) and southern Italy (Rosarno, Calabria) and were karyotyped using G-, C-, DA/DAPI-, and AluI-banding. All karyotypes had 2n = 54 chromosomes and seemingly identical autosomal banding. The sex chromosomes of the southern Italian specimens, M. savii brachycercus, showed additional large blocks of heterochromatin. In the northern specimens, M. savii savii, the X chromosome is metacentric, whereas in the southern specimens of M. savii brachycercus the X chromosome is a much larger submetacentric chromosome, and the Y chromosome is more than twice the size of the Y in the northern specimens. DA/DAPI staining reveals three levels of fluorescent intensity in the sex chromosomes of the Calabrian specimens. The sex chromosomes of M. savii brachycercus also have the only AluI bands seen in either chromosome set. These data suggest a heterogeneous origin and composition of the C-band regions of these chromosomes. Preliminary data suggest that fertility is reduced in crosses between the two karyomorphs.
Karyotypes and systematics of Asian high-mountain voles, genus Alticola (Rodentia, Arvicolidae)
Authors: Hielscher K. , Stubbe A. , Zernahle K. , Samjaa R.
Published: May 2008

Six species/subspecies of Asian high-mountain voles, genus Alticola, were studied cytogenetically via conventional staining and C- and G-banding. The karyotypes are very similar. The standard karyotype, as in A. strelzovi strelzovi, consists of 56 chromosomes. These are split into 25 acrocentric pairs, one large subtelocentric pair, one small metacentric pair, a large acrocentric X chromosome, and a small Y chromosome, which varies in shape. Constitutive heterochromatin is almost entirely restricted to small centromeric regions. A small submetacentric pair of autosomes in both subspecies of A. semicanus and a medium-sized Y chromosome in A. argentatus severtzovi are of importance in systematics. The data suggest that A. barakshin, A. semicanus, and A. argentatus are separate species.
Linkage map of eight human chromosome 11q markers, including DRD2, spanning 60 cM
Authors: Gelernter J. , Pakstis A.J. , Grandy D. , Litt M. , Retief A.E. , Kennedy J.L. , Hing-Loh A. , Schoolfield G. , Civelli O. , Kidd K.K.
Published: May 2008

We have constructed a linkage map of eight RFLP markers located on chromosome 11 q in the region of the dopamine D2 receptor gene (DRD2) recognized by probe hD2Gl. Abnormalities in dopaminergic neurotransmission mediated by this receptor have been implicated in several psychiatric disorders. The map was generated using six large reference families (from 294 to 419 individuals per locus), which are largely independent of the CEPH families, primarily using the LINKMAP and ILINK programs of the LINKAGE package of Lathrop and Lalouel. The most likely order and recombination frequencies are: cen-DllS146-INT2-D11S36-(DllS84, STMY)-DRD2-D11S29-PBGD-qter 0.001 0.213 0.123 0.001 0.158 0.035 0.093 The relative order of Dl 1S84-STMY, DRD2-D11S29, and D11S146-INT2 could not be resolved reliably. There were no significant sex differences in recombination frequency. We introduce here a version of LINKMAP adapted to run under distributed parallel processing (LINDA-LINKMAP). Using pairwise analyses, we have also placed D11S421 proximal to this group.
Regional mapping of the gene for autosomal dominant spinocerebellar ataxia (SCA1) by localizing the closely linked D6S89 locus to 6p24.2→p23.05
Authors: Volz A. , Fonatsch C. , Ziegler A.
Published: May 2008

The locus for one subtype of autosomal dominant spinocerebellar ataxias (SCA1) is closely linked (within 1–2 cM) to D6S89, which contains a highly polymorphic dinucleotide repeat sequence. D6S89 has been mapped previously to 6p24→p21.3, between the HLA and F13A1 loci. Mutant cell lines were used to correlate the absence or presence of D6S89 with cytogenetically detectable interstitial 6p deletions. The results allowed us to map D6S89 to the 6p24.2→p23.05 region. The close linkage of SCA1 to D6S89 indicates that this locus is most likely located in the 6p24→p23 segment.
Unusual distribution of Zfy and Zfx sequences on the sex chromosomes of the wood lemming, a species exhibiting XY sex reversal
Authors: Lau Y.-F.C. , Yang-Feng T.L. , Elder B. , Fredga K. , Wiberg U.H.
Published: May 2008

Sex reversal occurs naturally in the wood lemming (Myopus schisticolor) due to the presence in populations of this species of a variant (mutated) X chromosome, designated X*. Thus, X*Y animals develop into females, whereas XY animals develop into normal males. Chromosome mapping by in situ hybridization of DNA sequences homologous to the human ZFY gene localized the wood lemming Zfx sequences to region p12→p11 on both the wild-type X and the mutated X* chromosomes, at or proximal to a presumed breakpoint (Xp12) involved in the generation of the X* chromosome from the normal X, and Zfy sequences along the entire short arm of the Y chromosome. Differences between Zfx and Zfx* were readily detected by Southern blot analysis. However, both the Zfx and Zfx* genes expressed similarly sized transcripts in all adult somatic tissues investigated. Although the precise molecular difference between the Zfx and Zfx* genes is still unknown, their chromosomal location suggests that either Zfx or some other closely linked gene(s) on the X chromosome may be a major X-linked sex-determining gene, Tdx, which in the X* chromosome fails to interact properly with the Y-linked testis-determining gene, Tdy, thus causing X*Y embryos to develop into females. At least 15 copies of wood lemming Zfy sequences are distributed along the short arm of the Y chromosome. Northern hybridization analyses of adult tissues and somatic cell lines indicated that these Zfy repeats were transcriptionally inactive. Normally, 3-kb Zfy (ZFY) transcripts are readily detected in mouse and human testes, especially in the germ cells. It has therefore been postulated that expression of the Zfy (ZFY) gene may be important for spermatogenesis. Whether the lack of sufficient Zfy transcripts in the testis of the adult wood lemming has any impact on spermatogenesis in this species is still to be elucidated by further studies.
Genetic linkage analysis places locus DXS250 between locus DXYS1 and locus DXS3 in Xq21.3
Authors: Epting S. , Schwartz C.
Published: May 2008

The locus DXS250, which is linked to the Allan-Herndon type of X-linked mental retardation, maps between DXS3 and DXYS1 in a panel of 40 families established by the Centre d’Etude du Polymorphisme Humain, Paris.
Heterosynapsis and axial equalization of the sex chromosomes of the northern bobwhite quail
Authors: Hogan K.M. , Jarrell G.H. , Ryder E.J. , Greenbaum I.F.
Published: May 2008

The pairing behavior of the Z and W chromosomes in the female northern bobwhite quail (Colinus virginianus) was analyzed by electron microscopy of silver-stained synaptonemal complexes (SCs). After autosomal pairing was completed, synapsis of the sex chromosomes initiated at the short-arm end of the W chromosome and one end of the Z chromosome. Synapsis then progressed unidirectionally, producing a sex bivalent in which the entire length of the W axis was paired with an equivalent length of the Z axis. Progressive contraction and asymmetrical twisting of the Z axis ultimately resulted in a fully paired configuration with aligned axial ends. Further contraction of the Z axis reduced the extent of asymmetrical twisting such that only the nonaligned centromeric regions distinguished the SC of the ZW bivalent from SCs of similar-sized autosomes in late-pachytene nuclei. Quantitative analyses indicated that the length of the Z axis shortened significantly during the adjustment process, whereas no significant difference occurred in the length of the W axis. The nonalignment of the centromeric regions during transitional stages of ZW synapsis indicates that direct heterosynapsis of nonhomologous segments, followed by axial equalization of the length inequality, is responsible for the length adjustment during synapsis in the sex chromosomes of the bobwhite quail.