bluuebunny/crossref_metadata_2025 huggingface dataset:
Capacity-Demand-Diagram Methods Based on Inelastic Design Spectrum
Authors: Chopra Anil K. , Goel Rakesh K.
Published: July 2003

An improved capacity-demand-diagram method that uses the well-known constant-ductility design spectrum for the demand diagram is developed and illustrated by examples. This method estimates the deformation of inelastic SDF systems consistent with the selected inelastic design spectrum, while retaining the attraction of graphical implementation of the ATC-40 Nonlinear Static Procedure. One version of the improved method is graphically similar to ATC-40 Procedure A whereas the second version is graphically similar to ATC-40 Procedure B. However, the improved procedures differ from ATC-40 procedures in one important sense. The demand diagram used is different: the constant-ductility demand diagram for inelastic systems in the improved procedure versus the elastic demand diagram in ATC-40 for equivalent linear systems. The improved method can be conveniently implemented numerically if its graphical features are not important to the user. Such a procedure, based on equations relating the yield strength reduction factor, Ry, and ductility factor, μ, for different period, Tn, ranges, has been presented, and illustrated by examples using three different Ry - μ - Tn relations.
Influence of Viscoelastic Dampers on the Seismic Response of a Lightly Reinforced Concrete Flat Slab Structure
Authors: Hayes John R. , Foutch Douglas A. , Wood Sharon L.
Published: July 2003

A 1/3-scale model of a section of a three-story lightly reinforced concrete flat slab structure was constructed. Researchers installed a viscoelastic damper (VED) seismic rehabilitation system on the model and subjected it to seismic simulations on a shaking table. Successive simulations were conducted with increasing base accelerations until the horizontal displacement limit of the shaking table was reached. The dampers were then removed, and the simulations were repeated until structural failure occurred. This paper summarizes the responses of the model. Brief comparisons of the responses of the model with and without VEDs installed are made. The VEDs improved energy dissipation characteristics and serviceability of the structure by reducing interstory displacements. Earthquake simulation responses indicated that the damper configuration that was employed in the experimental investigation permitted rotations of the VEDs, which lowered their energy dissipation efficiency. An alternate arrangement for the VEDs is proposed to alleviate this problem.
Development of Maximum Considered Earthquake Ground Motion Maps
Authors: Leyendecker Edgar V. , Hunt R. Joe , Frankel Arthur D. , Rukstales Kenneth S.
Published: July 2003

The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. The spectral response accelerations are obtained from maps prepared following the recommendations of the Building Seismic Safety Council's (BSSC) Seismic Design Procedures Group (SDPG). The SDPG-recommended maps, the Maximum Considered Earthquake (MCE) Ground Motion Maps, are based on the U.S. Geological Survey (USGS) probabilistic hazard maps with additional modifications incorporating deterministic ground motions in selected areas and the application of engineering judgement. The MCE ground motion maps included with the 1997 NEHRP Provisions also serve as the basis for the ground motion maps used in the seismic design portions of the 2000 International Building Code and the 2000 International Residential Code. Additionally the design maps prepared for the 1997 NEHRP Provisions, combined with selected USGS probabilistic maps, are used with the 1997 NEHRP Guidelines for the Seismic Rehabilitation of Buildings.
Model Code Design Force Provisions for Elements of Structures and Nonstructural Components
Authors: Drake Richard M. , Bragagnolo Leo J.
Published: July 2003

With the publication of the 1997 Uniform Building Code ( UBC) and the 1997 NEHRP Recommended Provisions for the Seismic Regulations for New Buildings and Other Structures, there has been a significant change in the earthquake design force provisions for buildings, structures, elements of structures and nonstructural components. Engineers and architects need to become informed regarding a variety of earthquake design force provisions, primarily those published in the UBC and those developed as part of the NEHRP Provisions. Both sources provide design force provisions for the building structural system and separate design force provisions for elements of structures and nonstructural components. This paper describes the development, evolution, and application of the earthquake design force provisions for elements of structures and nonstructural components.
New Provisions for the Seismic Design of Composite and Hybrid Structures
Authors: Deierlein Gregory G.
Published: July 2003

While there have been significant advances in the design and construction of composite steel-concrete building structures, their use in regions of high seismicity has been hindered by the lack of design criteria in building codes and specifications. This has prompted initiatives in the Building Seismic Safety Council and the American Institute of Steel Construction to develop seismic design provisions for composite structures. The 1997 edition of the AISC Seismic Provisions includes a new section with requirements for composite steel-concrete structures that are cross-referenced by the general seismic loading and design criteria in the 1997 NEHRP Provisions and the 2000 International Building Code (final draft). Intended to complement existing provisions for steel, reinforced concrete and composite structures in the AISC-LRFD Specification and the ACI 318 Building Code, these new provisions provide an important resource for seismic design of composite structural systems, members, and connections.
Yield Point Spectra for Seismic Design and Rehabilitation
Authors: Aschheim Mark , Black Edgar F.
Published: July 2003

A new spectral representation of seismic demand is described for use in the seismic design of new structures and in the evaluation and rehabilitation of existing structures. Yield Point Spectra (YPS) retain the intuitive appeal of the Capacity Spectrum Method (Freeman 1978) and join the Nonlinear Static Procedures of FEMA 273/274 (1997) and ATC 40 (1996) for use in estimating displacement demands. YPS also may be used to establish admissible combinations of strength and stiffness for the design of new structures to limit system ductility and drift to arbitrary values. Graphical procedures allow admissible design regions to be established to satisfy multiple performance objectives. YPS computed for 15 ground motions classified as Short Duration, Long Duration, or as containing near-fault Forward Directivity pulses are presented for bilinear and stiffness-degrading hysteretic models.
Isolated Buildings and the 1997 UBC Near-Source Factors
Authors: Hall John F. , Ryan Keri L.
Published: July 2003

Computer simulations are employed to assess the effects of near-source ground motions on base-isolated buildings that meet the provisions of the 1997 Uniform Building Code. A six-story base-isolated building designed for Nv = 1.6 exhibits essentially elastic structural behavior when subjected to six actual ground motions containing strong near-source effects. However, two simulated records, one intended to represent the most severe motions from the 1994 Northridge earthquake and the other a strong motion from a hypothetical Mw7.0 thrust earthquake produce larger responses well into the nonlinear range. In addition, a 113 cm ground displacement pulse of three-second duration, which is close to the period of the isolated buildings, causes story drifts of nearly 5% for the Nv = 1.6 design and over 2% for a stronger Nv = 2 design. Such drifts are effectively reduced when supplemental dampers are added alongside the isolators. The original Nv = 1.6 design with supplemental damping in the amount of 20% of critical experiences only 1.3% drift for the same three-second ground displacement pulse.
Torsional Displacements in Base-Isolated Buildings
Authors: Jangid R. S. , Kelly J. M.
Published: July 2003

An analytical study of the effects of torsional coupling on the seismic response of a base-isolated building is presented. The isolated structure is modeled as a rigid deck supported on axially inextensible bearings. The governing equations of motion for the coupled lateral-torsional response of the system are derived. The eccentricity in the system is that specified by the Uniform Building Code (UBC). The displacement response of the isolated system with different combinations of building configuration, isolation damping, and the ratio of uncoupled torsional to lateral frequency of the system is investigated. The response of the isolated structure under a variety of near-fault and other earthquake ground motions is compared to that obtained by use of response spectrum analysis. In the response spectrum analysis the accuracy of several modal combination rules is evaluated. It is shown that torsional coupling can influence the response of the isolated structure, but if the layout of the isolation bearings is such that the torsional frequency is larger than the lateral frequency, the effect is reduced and the usual modal combination rules work well. It is also shown that in this case, the UBC static formula for the additional isolator displacements due to torsion is conservative.
Variations between Foundation-Level and Free-Field Earthquake Ground Motions
Authors: Stewart Jonathan P.
Published: July 2003

Strong motion data from sites having both an instrumented structure and free-field accelerograph are compiled to evaluate the conditions for which foundation recordings provide a reasonably unbiased estimate of free-field motion with minimal uncertainty. Variations between foundation and free-field spectral acceleration are found to correlate well with dimensionless parameters that strongly influence kinematic and inertial soil-structure interaction phenomena such as embedement ratio, dimensionless frequency (i.e., product of radial frequency and foundation radius normalized by soil shear wave velocity), and ratio of structure-to-soil stiffness. Low frequency components of spectral acceleration recorded on shallowly embedded foundations are found to provide good estimates of free-field motion. In contrast, foundation-level peak ground acceleration (both horizontal and vertical) and maximum horizontal velocity, are found to be de-amplified. Implications for ground motion selection procedures employed in attenuation relations are discussed, and specific recommendations are made as to how these procedures could be improved.
Probabilistic Earthquake Scenarios: Extending Risk Analysis Methodologies to Spatially Distributed Systems
Authors: Chang Stephanie E. , Shinozuka Masanobu , Moore James E.
Published: July 2003

This paper proposes a methodology by which probabilistic risk analysis methods can be extended to the assessment of urban lifeline systems. Probabilistic hazard information is commonly used for site-specific analysis. However, for such systems as highway networks, electric power grids, and regional health care delivery systems, the spatial correlation between earthquake ground motion across many sites is important in determining system functionality. The methodology developed in this paper first identifies a limited set of deterministic earthquake scenarios and evaluates infrastructure system-wide performance in each. It then assigns hazard-consistent probabilities to the scenarios in order to approximate the regional seismicity. The resulting probabilistic scenarios indicate the likelihood of exceeding various levels of system performance degradation. A demonstration for the Los Angeles study area highway network suggests that there is roughly a 50% probability of exceedance of Northridge-level disruption in 50 years. This methodology provides a means for selecting representative earthquake scenarios for response or mitigation planning.
Displacement-Based Seismic Design for Coupled Wall Systems
Authors: Munshi Javeed A. , Ghosh S. K.
Published: July 2003

This paper presents a displacement-based approach for the seismic design of coupled reinforced concrete shear walls in buildings. Two lateral load-resisting systems, one utilizing weakly coupled walls and the other using adequately coupled walls, are designed and analyzed for regions of high seismicity. The effect of beam-to-wall strength ratio on various response parameters is studied. The analysis results indicate that weakly coupled walls tend to develop excessive ductility demand and biased response under some critical ground motions. Walls that are adequately coupled produce displacement and ductility consistent with the design. Selecting an optimum value for the beam-to-wall strength ratio can minimize the ductility demand in the walls. The higher mode shear seems to decrease with an increase in the beam-to-wall strength ratio. Earthquakes that are capable of producing a large displacement pulse early during the ground shaking may adversely influence the subsequent response of the coupled wall system.
Empirical Study of Sediment-Filled Basin Response: The Case of Taipei City
Authors: Sokolov Vladimir Yu , Loh Chin-Hsiung , Wen Kuo-Liang
Published: July 2003

We analyze the site response of the Taipei basin using the records obtained by the Taiwan Strong Ground Motion Instrumentation Program (TSMIP) network. Records of 66 earthquakes of M=2.6-6.5 with a hypocentral depth varying from 1 km to 118 km and hypocentral distances of up to 150 km are studied for 35 stations located within this triangle-shaped alluvium structure. The site response is obtained in terms of spectral ratios calculated by dividing of the site spectrum by the reference spectrum estimated for a hypothetical “very hard rock” site. The recently developed empirical source scaling and attenuation models for the Taiwan region are used for the reference spectra calculation. This approach allows us to evaluate the variability of spectral ratios due to uncertainties introduced by source and propagation path effects and variability in the site response itself. The characteristics of site response in the Taipei basin depend on the properties of soil deposits and, in general, may be described by 1-D models. However, there are some peculiarities of spectral ratios that show the influence of subsurface topography.
A Simplified Procedure to Assess the Seismic Response of Nonlinear Structures
Authors: Albanesi T. , Nuti C. , Vanzi I.
Published: July 2003

The paper presents an improvement of the iterative procedure proposed in the ATC 40 document to evaluate seismic response of nonlinear structures in terms of maximum displacement and acceleration, given the structural initial elastic period, the yielding acceleration and the hardening ratio in the plastic range. As a second issue the results of the procedure are compared with nonlinear step by step dynamic integration, with the bilinear and Takeda model, and with the assumptions of equal energy and equal displacement. Two case studies of existing reinforced concrete buildings are further examined. For the cases examined, the ATC 40 procedure is overall as or less precise than the simpler equal energy and equal displacement principles.
Seismic Fragility Curves for On-Grade Steel Tanks
Authors: O'Rourke Michael J. , So Pak
Published: July 2003

The study reported herein attempts to characterize the seismic behavior of cylindrical on-grade, steel liquid storage tanks subject to the ground shaking hazard. The behavior is quantified by fragility curves that resulted from an analysis of the reported performance of over 400 tanks in nine separate earthquake events. The damage states used herein to characterize damage (i.e., slight, moderate, etc.) are intended to mirror damage state descriptions in the HAZUS Earthquake Loss Estimation Methodology. The amount of ground shaking is quantified by the peak ground acceleration (PGA) at the site. The influence of the tank's height to diameter ratio, H/D, as well as the relative amount of stored contents, % Full, are investigated and were found to have had a significant effect upon tank seismic performance. Finally, the fragility curves developed herein are compared to corresponding relations currently available in the technical literature.
Direct Displacement-Based Design: Use of Inelastic vs. Elastic Design Spectra
Authors: Chopra Anil K. , Goel Rakesh K.
Published: July 2003

Direct displacement-based design requires a simplified procedure to estimate the seismic deformation of an inelastic SDF system, representing the first (elastic) mode of vibration of the structure. This step is usually accomplished by analysis of an “equivalent” linear system using elastic design spectra. In this paper, an equally simple procedure is developed that is based on the well-known concepts of inelastic design spectra. We demonstrate that the procedure provides the following: (1) accurate values of displacement and ductility demands, and (2) a structural design that satisfies the design criteria for allowable plastic rotation. In contrast, the existing procedure using elastic design spectra for equivalent linear systems in shown to underestimate significantly the displacement and ductility demands. The existing procedure is shown to be deficient in yet another sense; the acceptable value of the plastic rotation, leaving an erroneous impression that the allowable plastic rotation constraint has been satisfied.
Characterization of Near-Source Ground Motions with Earthquake Simulations
Authors: Aagaard Brad T. , Hall John F. , Heaton Thomas H.
Published: July 2003

We examine the characteristics of long-period near-source ground motions by conducting a sensitivity study with variations in six earthquake source parameters for both a strike-slip fault ( M 7.0-7.1) and a thrust fault ( M 6.6-7.0). The directivity of the ruptures creates large displacement and velocity pulses in the forward direction. The dynamic displacements close to the fault are comparable to the average slip. The ground motions exhibit the greatest sensitivity to the fault depth with moderate sensitivity to the rupture speed, peak slip rate, and average slip. For strike-slip faults and thrust faults with surface rupture, the maximum ground displacements and velocities occur in the region where the near-source factor from the 1997 Uniform Building Code is the largest. However, for a buried thrust fault the peak ground motions can occur up-dip from this region.
Drift Spectrum vs. Modal Analysis of Structural Response to Near-Fault Ground Motions
Authors: Chopra Anil K. , Chintanapakdee Chatpan
Published: July 2003

A new measure of earthquake demand, the drift spectrum has been developed as an adjunct to the response spectrum, a central concept in earthquake engineering, in calculating the internal deformations of a structure due to near-fault ground motions with pronounced coherent pulses in the velocity and displacement histories. Compared in this paper are certain aspects of the elastic structural response to near-fault and far-fault ground motions. It is demonstrated that (1) the difference between drift and response spectra are not unique to near-fault ground motions; these differences simply reflect higher-mode response, which is larger due to near-fault ground motions; (2) response spectrum analysis (RSA) using existing modal combination rules can provide an estimate of structural response that is accurate to a useful degree; (3) these modal combination rules are similarly accurate for near-fault and far-fault ground motions although the underlying assumptions are not satisfied by near-fault excitations; and (4) RSA is preferable over the drift spectrum in computing structural response because it represents standard engineering practice and is applicable to a wide variety of structures.
A Proposed Damage Model for RC Bridge Columns under Cyclic Loading
Authors: Hindi Riyadh A. , Sexsmith Robert G.
Published: July 2003

This paper defines a damage index based on the predicted hysteretic behavior of a concrete column. The model yields a damage index at a point in the time history for the element, based on the predicted monotonic response from the point in time to failure. The model takes into account the parameters that describe the hysteretic behavior: stiffness degradation, strength deterioration, and ultimate displacement reduction. Therefore, the damage model is accumulative and it combines energy, ductility, and low-cycle fatigue. The model is based on the work needed to fail a reinforced concrete column monotonically after it experiences a cyclic loading. The model modifies the ultimate displacement that the column can achieve, due to low-cycle fatigue in the longitudinal reinforcement using the Coffin-Manson rule in combination with Miner's hypothesis. The proposed model is applied to bridge columns tested by others, and compared to existing damage indices. The proposed model gives a realistic prediction of damage throughout the loading cycles for several test specimens investigated.
Comparative Study of the Inelastic Seismic Demand of Eastern and Western Canadian Sites
Authors: Tremblay Robert , Atkinson Gail M.
Published: July 2003

The damage potential of earthquake ground motions compatible with site-specific 2% in 50 year uniform hazard spectra is compared at two North American sites in areas of moderate seismic hazard: Montreal, in the east, and Vancouver, along the west coast. For Vancouver, crustal, subcrustal and Cascadia subduction ground motion earthquake ensembles are considered. Nonlinear dynamic analyses of bi-linear single-degree-of-freedom oscillators exhibiting various ductility levels and damage laws were performed to determine R factors required to prevent structural collapse for each site and each system. Then, inelastic response parameters were computed for the general design case, wherein a prescribed R factor is used for a given system irrespective of tectonic region or structural period. The results show that the R factors vary with the ductility level, the damage law, the structural period, and the tectonic region. Neglecting the latter two dependencies in design, as is current practice, may lead to significant discrepancies in the level of protection achieved for different structures in different regions.
A Simple Method for the Design of Optimal Damper Configurations in MDOF Structures
Authors: García Diego López
Published: July 2003

Existing methods for the design of optimal configurations of supplemental dampers are usually not simple enough to be used routinely and typically lead to different damper sizes at virtually every story. One exception is the Sequential Search Algorithm, which lets the designer control the number of different damper sizes. In this paper, a simplification to the Sequential Search Algorithm is proposed so that the resulting procedure, designated as Simplified Sequential Search Algorithm, can be easily integrated into conventional design procedures used by practicing engineers dealing with damper-added structures. In the case of linear viscous dampers, it was found that the efficiency of damper configurations given by the proposed Simplified Sequential Search Algorithm is comparable to the efficiency of damper configurations given by more sophisticated procedures. The applicability of the method is limited to those cases where the response of the structure with added dampers remains linear.
Anatomy of Plant Cells
Authors: Wetzstein Hazel Y. , He Yi
Published: July 2003

Introduction

Leaf Anatomy ofIn Vitro‐Grown Plants

Hyperhydricity

Anatomy of Somatic Embryogenic Cultures

Anatomy of Organogenic Cultures

Anatomy of Plant Protoplast

Anatomy of Cell Suspension Cultures

Anatomy of Callus Cultures

Bibliography
Animal Cell Types,
B
Cell Lineage
Authors: Walker K.B.
Published: July 2003

The B‐Cell Lineage: Introduction

B Cells In Vivo

B Cells In Vitro

Bibliography
Animal Cell Types, Liver Cells
Authors: Stacey G.
Published: July 2003

HepatocytesIn Vivo

HepatocytesIn Vitro

Hepatic Cell Lines

Conclusion

Bibliography
Bioreactors, Continuous Culture of Plant Cells
Authors: ten Hoopen H.J.G.
Published: July 2003

Introduction

Assumptions in Continuous Culture Theory and Their Pitfalls

The Practical Setup of a Continuous Culture

Mathematical Description of Continuous Culture

Applications of the Continuous Cultivation of Plant Cells

Nomenclature

Bibliography
Bryophyte In Vitro Cultures, Secondary Products
Authors: Becker Hans
Published: July 2003

Introduction

Culture Conditions

Product Formation

Biotransformations

Biosynthetic Studies

Bibliography
Disease Resistance in Transgenic Plants
Authors: Robison Mary , Pauls K. Peter
Published: July 2003

Introduction

The Plant Resistance Response

Resistance from
R
Genes

Resistance from Manipulation of Reactive Oxygen Species

Resistance from Cell Death

Resistance from Pathogenesis‐Related Proteins

Resistance from Phytoalexins

Resistance from Antimicrobial Peptides and Proteins

Pathogen‐Derived Resistance

Resistance from Novel Sources

Conclusions

Bibliography
Haploid Plant Production: Pollen/Anther/Ovule Culture
Authors: Veilleux Richard E.
Published: July 2003

Anther Culture

Microspore (Pollen) Culture

Ovule Culture

Conclusion

Bibliography
Measurement of Cell Viability
Authors: Butler M.
Published: July 2003

Introduction

Dye Exclusion

Vital Stains

Dual Fluorescent Staining

Release of Radioactive Chromium (51Cr)

Tetrazolium Assay

Colony‐Forming Assay

Lactate Dehydrogenase Determination

Intracellular Energy Charge

Rate of Protein Synthesis

Rate of DNA Synthesis

Bibliography
Plant Cell Cultures, Secondary Product Accumulation
Authors: Pras Niesko
Published: July 2003

Introduction

Manipulation of Culture Conditions

Cell Selection

Induction of Differentiation in Plant Cell Cultures

Bioconversion

Genetic Approaches

Conclusions

Bibliography
Protein Processing, Endocytosis and Intracellular Sorting of Growth Factors
Authors: Sorkin Alexander
Published: July 2003

Introduction

Endocytosis of Growth Factor Receptors

Receptor Recruitment into Clathrin‐Coated Pits

Molecular Mechanisms of Internalization

Pathway Through Endosomal Compartments

Kinetics of Intracellular Trafficking: Recycling Versus Degradation

Mechanism of Receptor Sorting in Endosomes

Other Types of Signaling Receptors

Perspectives

Acknowledgments

Bibliography
Transformation of Plants
Authors: Siemens Johannes , Pickardt Thomas
Published: July 2003

Introduction

Agrobacterium‐Meditated Gene Transfer

Direct Gene Transfer into Protoplasts

Direct Gene Transfer—Biolistic Approach

Direct Gene Transfer Across the Cell Wall Without Carrier Particles

In Planta Transformation—Unusual Methods for a Tiny Plant

Viral Transformation Vectors

Conclusions and Remaining Problems

Acknowledgment

Bibliography
Beneficial Effects of AlN as Sintering Aid on Microstructure and Mechanical Properties of Hot‐pressed ZrB2
Authors: Monteverde F. , Bellosi A.
Published: July 2003

Higher density of ZrB2 ceramics than with the pure material is achieved when 4.6 % of aluminum nitride are added before hot‐pressing as a sintering aid. AlN supports densification and prevents grain coarsening, mainly by virtue of its ability to remove the boron oxide layer that otherwise covers ZrB2 particles. The new material (see Figure for an SEM image of a polished section) has outstanding mechanical properties, e.g. strength values of 600 and 200 MPa at 25 and 1500 °C.
Friction Stir Welding – Recent Developments in Tool and Process Technologies
Authors: Thomas W.M. , Johnson K.I. , Wiesner C.S.
Published: July 2003

Improved weld integrity, reduced upper‐plate thinning, and higher welding speeds are some striking results of progress recently made in the field of friction‐stir welding through improvements of tools and processes. One technique, labelled Re‐Stir™, in particular, appears promising since it generates essentially symmetrical welds (see Figure for a cross‐section of the notch) and is potentially suitable for welding of dissimilar materials.
Preparation of the Intermediate Layers on CoNiCrMo‐Alloys Using Alkaline Treatment for Improving the Bonding of Bioceramic Coating
Authors: Wang T. , Dorner‐Reisel A. , Müller E.
Published: July 2003

Can alkaline pretreatment improve the bond between metallic implants and hydroxyapatite bioceramic coatings? Very much so, but it affords proper choice of the base. Treatment with 10 M NaOH did not result in a crystalline coating on CoNiCrMo whereas saturated Ca(OH)2solution produces a stable, homogeneous coating of Ca2Co2O5as a bridge compound. The Figure shows two examples of metallic knee prosthesis parts made of CoNiCrMo and CoCrMo, resp. for use in such implants.
Non‐syndromic hemihyperplasia in a male and his mother
Authors: Slavotinek Anne M. , Collins Michael T. , Muenke Maximilian
Published: July 2003

We present two family members with non‐syndromic hemihyperplasia (HHP), which developed in adolescence. We have reviewed reported familial cases of HHP and conclude that presentation is similar to sporadi cases and that all affected family members have been related through a maternal relative. Published 2003 Wiley‐Liss, Inc.
Turner phenotype in a girl with a 45,X/46,XX/47,XX,+18 mosaicism
Authors: Lorda‐Sanchez Isabel , Trujillo Maria Jose , Gomez‐Garre Pilar , de Alba Marta Rodríguez , Gonzalez‐Gonzalez Cristina , García‐Hoyos Maria , Ayuso Carmen , Ramos Carmen
Published: July 2003

We report a girl with Turner syndrome phenotype, whose karyotype on amniocyte culture was 45,X, while cytogenetic analysis on peripheral blood lymphocytes showed the presence of a mosaic chromosome constitution with three different cell lines: 45,X[5]/46,XX[3]/47,XX,+18 [35]. No signs of trisomy 18 were observed and a follow up during childhood revealed normal psychomotor development. Parental origin and mechanism of formation were studied using high polymorphic microsatellites and Quantitative Fluorescent PCR. The 18‐trisomic cells showed one paternal allele and two maternal homozygous alleles at different loci of chromosome 18, suggesting a maternal M‐II meiotic or a postzygotic error. A biparental origin of the X‐alleles in the trisomic cells were determined, being the paternal allele retained in the 45,X cells. The possible mechanism of formation implying meiotic and/or mitotic errors is discussed. © 2003 Wiley‐Liss, Inc.
Gorlin syndrome with ulcerative colitis in a Japanese girl
Authors: Fujii Katsunori , Miyashita Toshiyuki , Omata Taku , Kobayashi Kazuhiko , Takanashi Jun‐ichi , Kouchi Katsunori , Yamada Masao , Kohno Yoichi
Published: July 2003

We present the case of a 14‐year‐old Japanese girl who had both Gorlin syndrome and ulcerative colitis. She had complained of blood stools for 6 months and severe scoliosis from her infancy. Physical examination revealed multiple nevi, palmar and plantar pits, jaw cysts, and calcification of the falx cerebri, leading to the diagnosis of Gorlin syndrome. Total colonoscopy revealed an edematous and spotty bleeding mucosa extending from the anus to the transverse colon. Histological examination was also compatible with ulcerative colitis. Thus, we diagnosed her as having Gorlin syndrome with ulcerative colitis. Gene analysis revealed a mutation, 1247InsT, in the human patched gene (PTCH), resulting in the truncation of PTCH protein. Since Gorlin syndrome and ulcerative colitis are rare disorders in childhood, this association is interesting, suggesting a correlation between the hedgehog signaling and intestinal disorders. © 2003 Wiley‐Liss, Inc.
An acceptor splice site mutation in HOXD13 results in variable hand, but consistent foot malformations
Authors: Kan Shih‐hsin , Johnson David , Giele Henk , Wilkie Andrew O.M.
Published: July 2003

HOXD13 is the most 5′ of the HOXD cluster of homeobox genes in chromosome band 2q31.1. Heterozygous expansions of a polyalanine tract in HOXD13 are typically associated with synpolydactyly characterized by insertional digit duplication associated with syndactyly. We screened for mutations of HOXD13 in patients with a variety of limb malformations and identified a novel heterozygous mutation (758‐2delA) in a three‐generation family without the typical synpolydactyly phenotype in the hands, but with bilateral partial duplication of the 2nd metatarsals within the first web space of the feet. This mutation locates in the acceptor splice site of exon 2 and is predicted to cause failure of normal splicing of HOXD13. The foot abnormality in this family is similar to that described in two families by Goodman et al. [1998: Am. J. Hum. Genet. 63: 992–1000] in which different deletions of HOXD13 were reported. These findings together lend support to a distinct phenotype resulting from haploinsufficiency of HOXD13. © 2003 Wiley‐Liss, Inc.
De novo paracentric inversion (X)(q26q28) with features mimicking Prader–Willi syndrome
Authors: Florez Luisa , Anderson Mary , Lacassie Yves
Published: July 2003

Different genetic and non‐genetic disorders, including several chromosomal abnormalities, may mimic Prader–Willi syndrome (PWS). We report on an 11‐year‐old girl with features reminiscent of PWS due to an unreported de novo paracentric inversion Xq26q28. Microdeletion 15q11‐q13 and maternal uniparental disomy 15 were ruled out. The importance of chromosomal studies in addition to molecular analysis on patients with features suggestive of PWS is stressed. © 2003 Wiley‐Liss, Inc.
Myoclonus in a patient with a deletion of the ε‐sarcoglycan locus on chromosome 7q21
Authors: DeBerardinis Ralph J. , Conforto Danielle , Russell Karen , Kaplan Jennifer , Kollros Peter R. , Zackai Elaine H. , Emanuel Beverly S.
Published: July 2003

Autosomal dominant myoclonus‐dystonia syndrome (MDS) is characterized by myoclonic and/or dystonic movements with onset as early as infancy. In most families, MDS is caused by mutations in the gene SGCE, which encodes ε‐sarcoglycan and is located on chromosome 7q21. Data from several sources, including multi‐generation pedigrees revealing parent‐of‐origin effects on MDS penetrance, suggest that SGCE is maternally imprinted. We present a 32‐month‐old patient with an interstitial deletion affecting chromosome 7q21, and a phenotype including myoclonus, microcephaly, short stature, dysmorphic face and language delay. We used fluorescence in situ hybridization (FISH) to estimate the size of our patient's deletion (9.0–15 Mbp) and to confirm absence of SGCE on the affected chromosome. Polymerase chain reaction (PCR) analysis of polymorphic markers in the region revealed that the paternally inherited chromosome contained the deletion, consistent with a model of maternal SGCE imprinting. Our patient is the first case of MDS caused by complete deletion of SGCE, and represents a new contiguous gene disorder. The case underscores the need to consider chromosomal deletions in patients whose phenotypes are more complex than the classic presentation of a known disease. © 2003 Wiley‐Liss, Inc.
A novel 5q35.3 subtelomeric deletion syndrome
Authors: Rauch Anita , Beese Maike , Mayatepek Ertan , Dörr Helmut‐Günther , Wenzel Dieter , Reis André , Trautmann Udo
Published: July 2003

We observed a novel 3.5 Mb 5q subtelomeric deletion in a 3‐year‐old girl with developmental delay, hypotonia and multiple minor anomalies. Comparison of her phenotype with the few published patients with terminal 5q35 deletions revealed several overlapping features, but also showed remarkable differences such as shortness of stature versus macrosomia. After the report of 5q35.3 microdeletions in Sotos syndrome we integrated the published BACs into the public draft sequence and exactly mapped the deletion size in our patient by FISH analysis with 15 BAC probes. We demonstrated that the deletion in our patient is immediately adjacent to the reported Sotos syndrome deletion site. Subtracting the symptoms of Sotos syndrome from the published patients with larger 5q35.3 deletions allowed us to delineate a distinct phenotype of prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia and delay of reaching motor milestones, but speech development within normal limits, wide fontanels, failure to thrive with postnatal short stature, and multiple minor anomalies such as mildly bell‐shaped chest, minor congenital heart disease, and a distinct facial gestalt, associated with the novel 3.5 Mb cryptic deletion. We further showed in our patient that the deletion of the LCT4 synthase gene results in a reduction of cysteinyl leukotriene synthesis to about 65% compared to normal values. The prenatal nuchal lymphedema associated with this deletion syndrome my be related to the deletion of the FLT4 gene causing autosomal dominant primary lymphedema and contributes to the differential diagnosis of increased fetal nuchal translucency. © 2003 Wiley‐Liss, Inc.
Das Ribosom unter der Lupe
Authors: Wilson Daniel N. , Nierhaus Knud H.
Published: July 2003

Fast zwanzig Jahre lang haben Kristallographen nach der Struktur der Ribosomen gesucht, der größten und kompliziertesten RNA‐Protein‐Komplexe in der Zelle. Wie alle Ribosomen setzt sich auch das Ribosom einer kleinen Bakterienzelle aus einer großen und kleinen Untereinheit zusammen. Das bakterielle Ribosom umfasst drei RNA‐Moleküle mit mehr als 4000 Ribonucleotiden und 54 unterschiedlichen Proteinen. Herausragendes Ereignis der letzten Jahren war das Erreichen der atomaren Auflösung der großen und kleinen Untereinheit sowie das einer 5.5‐Å‐Struktur des vollständigen 70S‐Ribosoms von Thermus thermophilus. Damit war es möglich, Kristalle der Untereinheiten mit kleinen Liganden zu tränken, was unser Verständnis der zentralen Funktionen des Ribosoms revolutioniert hat. Zusammen mit den Vorzügen kryoelektronenmikroskopischer Studien von Translationskomplexen entstand eine Sammlung von Momentaufnahmen ribosomaler Funktionen, aus denen ein filmähnlicher Ablauf der Translation abgeleitet werden konnte. Analysen jüngeren Datums von Heferibosomen lassen eine erstaunliche strukturelle Deckung mit den Ribosomen der Prokaryoten erkennen. Dieser Aufsatz soll ein bakterielles Ribosom durch einen Translationszyklus begleiten, wobei insbesondere solche Merkmale hervorgehoben werden, die sich in den Ribosomen aller Organismen wiederfinden.
The Ribosome through the Looking Glass
Authors: Wilson Daniel N. , Nierhaus Knud H.
Published: July 2003

For almost 20 years crystallographers have sought to solve the structure of the ribosome, the largest and most complicated RNA–protein complex in the cell. All ribosomes are composed of a large and small subunit which for the humble bacterial ribosome comprise more than 4000 ribonucleotides, 54 different proteins, and have a molecular mass totaling over 2.5 million Daltons. The past few years have seen the resolution of structures at the atomic level for both large and small subunits and of the complete 70S ribosome from Thermus thermophilus at a resolution of 5.5‐Å. Soaking of small ligands (such as antibiotics, substrate analogues, and small translational factors) into the crystals of the subunits has revolutionized our understanding of the central functions of the ribosome. Coupled with the power of cryo‐electron microscopic studies of translation complexes, a collection of snap‐shots is accumulating, which can be assembled to create a likely motion picture of the bacterial ribosome during translation. Recent analyses show yeast ribosomes have a remarkable structural similarity to bacterial ribosomes. This Review aims to follow the bacterial ribosome through each sequential “frame” of the translation cycle, emphasizing at each point the features that are found in all organisms.
Cover Picture: Serine Octamer Reactions: Indicators of Prebiotic Relevance (Angew. Chem. Int. Ed. 30/2003)
Authors: Takats Zoltan , Nanita Sergio C. , Cooks R. Graham
Published: July 2003

In the beginning the origin of life involved a series of homochiral chemical reactions. Some of these may have involved serine and its homochiral octamer, as shown. Many of these reactions occur in a chirally selective fashion. The chiral exchange reactions favor the enantiomers present in modern life (L‐amino acids, D‐sugars). More information on the homochiral serine octamer and its role in the prebiotic mechanisms that led to the origin of life are given by R. G. Cooks et al. on page 3521 ff.
Somatotopic mapping of chordotonal organ neurons in a primitive ensiferan, the New Zealand tree weta Hemideina femorata: I. femoral chordotonal organ
Authors: Nishino Hiroshi
Published: July 2003

The femoral chordotonal organ (FCO) in orthopteran insects comprises several hundred sensory neurons, making it one of the most complex insect proprioceptors. The sensory neurons are suspended from the proximal femur, connecting distally to ligaments and to a needle‐like apodeme extending from the proximal tibia. They monitor the position and movement of the tibia. To address how this complexity depends on evolutionary status and function, the morphology of the FCO neurons in the primitive orthopteran Hemideina femorata was investigated by staining small populations of identified afferents. As in crickets, the FCOs in all legs of the weta comprise partly fused ventral and dorsal scoloparia, with the former containing two groups of somata, the ventral group (VG) and the dorsal group (DG). However, the dendrites of the DG insert into thin connective tissue attached to the ventral side of the dorsal ligament, forming a “third scoloparium.” The VG afferents terminate mainly in the motor association neuropils, whereas afferents from the dorsal scoloparium neurons terminate exclusively in the vibratory neuropil as do the afferents from the subgenual organ, a substrate vibration detector. Several afferents originating in the DG have extensive terminations in the motor association‐, vibratory‐, and auditory‐processing neuropils, indicating lesser functional specialization than in the other groups. The evolutionary development of the FCO is discussed from a comparative viewpoint. J. Comp. Neurol. 464:312–326, 2003. © 2003 Wiley‐Liss, Inc.
Somatotopic mapping of chordotonal organ neurons in a primitive ensiferan, the New Zealand tree weta Hemideina femorata: II. complex tibial organ
Authors: Nishino Hiroshi , Field Laurence H.
Published: July 2003

Most ensiferan insects possess sets of highly specialized chordotonal organs in the proximal tibiae to detect conspecific auditory/vibratory signals or approach of predators. To date, most auditory/vibratory afferents have been classified according to their physiological properties and axonal projection morphology, but not to somatotopic origins. Hence, the functional specialization of identified receptor cells in the tibial organs remains uncertain. To address this question from an anatomical aspect, we investigated the structure of the weta, Hemideina femorata, tibial organs (the most elaborated tibial chordotonal organs among ensiferans) and their central projections by staining small numbers of receptor afferents from identified tibial organs. These organs comprise the “complex tibial organ,” including the subgenual organ (primary vibration detector) and its posterior complement, the accessory organ, and the crista acustica (primary auditory organ) and its proximal complement, the intermediate organ. Unlike reports of a membranous organ structure for homologs in other ensiferans, weta tibial organs contain receptor cells embedded in thick solid masses. Primary afferents project ipsilaterally to the medial ventral association center of thoracic ganglia, where axon terminals are arrayed topographically in different areas specific to each organ, except for almost complete overlap of afferents originating from the distal part of the crista acustica and from the intermediate organ. In contrast to somatotopic reflection of sensilla position on limbs, as known for mechanoreceptor hairs, the somatotopic projection map of the insect ear reveals topographic association with acoustic tracheae or tibial cuticular attachment sites, which in turn must reflect determinants of response sensitivity (e.g., frequency or threshold). J. Comp. Neurol. 464:327–342, 2003. © 2003 Wiley‐Liss, Inc.
Spontaneous regeneration of the corticospinal tract after transection in young rats: Collagen type IV deposition and astrocytic scar in the lesion site are not the cause but the effect of failure of regeneration
Authors: Iseda Tsutomu , Nishio Takeshi , Kawaguchi Saburo , Kawasaki Takayuki , Wakisaka Shinichiro
Published: July 2003

In young rats the corticospinal tract regenerated after a single transection of the spinal cord with a sharp blade, but regeneration failed if the transection was repeated to make a more traumatic injury. To identify cells and associated molecules that promote or impede regeneration, we compared expression of collagen type IV, glial fibrillary acidic protein (GFAP), and vimentin immunoreactivity (IR) at the lesion sites in combination with anterograde axonal tracing between animals with two types of transection. Axonal regeneration occurred as early as 18 hours after transection; regenerating axons penetrated vessel‐like structures with collagen type IV‐IR at the lesion site, while reactive astrocytes coexpressing GFAP‐ and vimentin‐IR appeared in the lesioned white matter. In contrast, when regeneration failed astrocytes were absent near the lesion. By 7 days sheet‐like structures with collagen type IV‐IR and astrocytic scar appeared in the lesioned white matter and persisted until the end of the observation period (31 days). On the basis of their spatiotemporal appearance, collagen type IV‐IR sheet‐like structures and the astrocytic scar follow, rather than cause, the failure of regeneration. The major sign, and perhaps cause, of failure of axonal regeneration is likely the prolonged disappearance of astrocytes around the lesion site in the early postinjury period. J. Comp. Neurol. 464:343–355, 2003. © 2003 Wiley‐Liss, Inc.
Increased expression of insulin‐like growth factor I augments the progressive phase of synaptogenesis without preventing synapse elimination in the hypoglossal nucleus
Authors: O'Kusky John Robert , Ye Ping , D'Ercole A. Joseph
Published: July 2003

The in vivo actions of insulin‐like growth factor I (IGF‐I) on synaptogenesis in the hypoglossal nucleus were investigated in transgenic mice that overexpress IGF‐I in the brain postnatally and in normal nontransgenic littermate controls. In a previous study using these mice, we found that IGF‐I increases the total volume of the hypoglossal nucleus by increasing the volume of neuropil rather than by increasing total neuron number; therefore, the progressive and regressive phases of synaptogenesis could be evaluated without the confounding effects of altered neuron number. The volume of the hypoglossal nucleus was significantly increased by 28% to 59% in transgenic mice after postnatal day (P) 7, whereas the total number of hypoglossal neurons did not differ significantly from controls. The numerical density of neurons was significantly decreased by 21% to 38% after P7, and the density of myelinated axons was significantly increased by 19%. Although the numerical density of synapses did not differ between groups at any age, the total number of synapses in transgenic mice was increased by 42% to 52% after P14. Total synapse number in controls increased from P7 (7.9 million) to peak values at P21 (36.0 million), followed by a significant decrease (33%) at P130 (24.2 million). In transgenic mice, total synapses increased from 8.2 million on P7 to 51.1 million on P21, followed by a significant decrease (28%) to 36.7 million at P130. Our results demonstrated that IGF‐I can stimulate a persistent increase in the number of hypoglossal synapses, thereby augmenting the progressive phase of synaptogenesis without preventing synapse elimination during the regressive phase. J. Comp. Neurol. 464:382–391, 2003. © 2003 Wiley‐Liss, Inc.