bluuebunny/crossref_metadata_2025 huggingface dataset:
Submicrometer period silicon diffraction gratings by porous etching
Authors: Nagy N. , Volk J. , Hámori A. , Bársony I.
Published: June 2005

We have developed a new technique to manufacture diffraction gratings on porous silicon and on silicon interface. Using holography facilitate to adjust the periodic length of gratings in the submicron range. The holographically exposured and developed photoresist applied on the silicon surface provides the mask for the ion implantation. The sinusoidal grating between the substrate and the porous silicon layer is achieved after the anodic etch process. The PS layer can be removed by alkali etching. Sinusoidal one‐ and two‐dimensional diffraction gratings have been produced with 375 nm periodic length. Their AFM images are shown. The diffraction efficiencies were measured. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation technique for macroporous morphology superlattice
Authors: Zheng J. , Christophersen M. , Bergstrom P. L.
Published: June 2005

In this work, the investigators studied etching conditions for generating macro porous silicon with different morphologies in p‐type (111) substrates. Both crystal orientation dependent growth of macropores and electric current direction dependent growth of macropores have been achieved. A superlattice structure, which consists of several layers of macroporous silicon with different morphologies, has been demonstrated by modulating the etch conditions during the anodization process. The morphology superlattice structure is developed for an inlet particle filter of a micro gas chromatograph (µGC). It may offer a number of other new MEMS applications. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modification of cubic susceptibility tensor in birefringent porous silicon
Authors: Zabotnov Stanislav V. , Konorov Stanislav O. , Golovan Leonid A. , Fedotov Andrei B. , Timoshenko Victor Yu. , Zheltikov Aleksei M. , Kashkarov Pavel K.
Published: June 2005

Polarization‐sensitive third‐harmonic generation in birefringent (110) porous silicon layers reveals a modification in the cubic susceptibility tensor of silicon caused by strongly anisotropic pores. The ratio $ (\chi _{1111} ^{(3)} + \chi _{1122} ^{(3)} / \chi _{3333} ^{(3)}) $ of cubic susceptibility tensor components for the porous layers is shown to be 40% higher than this ratio for crystalline silicon. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Use of porous GaAs electrodes in photoelectrochemical cells
Authors: Cojocaru A. , Simashkevich A. , Sherban D. , Tiginyanu I. , Ursaki V. , Tsiulyanu I. , Usatyi I.
Published: June 2005

The photoelectrochemical properties of semiconductor‐electrolyte solar cells with carbon auxiliary electrode and colloidal aqueous solution of Na2SiO3 have been investigated. Bulk n‐type single crystalline and nanoporous GaAs material were used as semiconductor electrodes. Current–voltage characteristics under different illumination intensities and spectral distribution of the photosensitivity were studied. The photopotential was found to reach values as high as 0.46 V for bulk n‐GaAs. The introduction of porosity in GaAs shifts the maximum of the spectral distribution of photosensitivity towards the longwavelength region and increases the short circuit current by a factor of two. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pore filling of macropores prepared in p‐type silicon by copper deposition
Authors: Harraz F. A. , Kamada K. , Sasano J. , Izuo S. , Sakka T. , Ogata Y. H.
Published: June 2005

Copper deposition into ordered macroporous silicon prepared in p‐type substrates was investigated by immersion plating and electrochemical deposition in an aqueous solution containing Cu2+ ions. When the sample was immersed in 0.1 M CuSO4 solution at the open circuit potential, Cu crystallites are clearly observed at the top surface and inside the pores. The deposition of Cu oxidizes the substrate simultaneously to SiO2. On the other hand, the potentiostatic deposition in the dark revealed that Cu deposits preferentially at the pore bottom and propagates towards the top surface. Furthermore, when the substrate was illuminated under cathodic potential, the Cu deposition was enhanced mainly at the top‐surface and around the pore walls. The different deposition behavior was compared and discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbonic anhydrase adsorption in porous silicon studied with infrared ellipsometry
Authors: Arwin H. , Karlsson L. M. , Kozarcanin A. , Thompson D. W. , Tiwald T. , Woollam J. A.
Published: June 2005

The refractive index N = n + ik of the protein bovine carbonic anhydrase (BCA) adsorbed in porous silicon layers is determined using infrared spectroscopic ellipsometry. Five absorption bands in the amide region are resolved. The distribution of the protein inside the porous matrix is modelled and it is found that more BCA per internal surface area are adsorbed in the upper part of the porous layer than in the bottom part. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silicon – rare earth doped xerogel and glass composites
Authors: Balakrishnan S. , Gun'ko Yurii K. , Perova T. S. , Rafferty A. , Astrova E. V. , Moore R. A.
Published: June 2005

The development of components for photonics applications is growing exponentially. The sol–gel method is now recognised as a convenient and flexible way to deposit oxide or glass films on a variety of hosts, including porous silicon. In the present work we incorporated erbium and europium doped xerogel into porous silicon and developed new porous silicon – rare earth doped glass composites. Various characteris‐ation techniques including FTIR, Raman Spectroscopy, Thermal Gravimetric Analysis and Scanning Electron Microscopy were employed in this work. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic nanoparticles – porous silicon composite material
Authors: Balakrishnan S. , Gun'ko Yurii K. , Perova T. S. , Venkatesan M. , Astrova E. V. , Moore R. A.
Published: June 2005

New composite magnetite – porous silicon materials have been prepared. The materials have been studied using various characterisation techniques such as Raman, XRD, magnetic measurements and SEM. Self‐organisation of magnetic particles into linear micro‐assemblies on the porous silicon surface has been observed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laterally stacked porous silicon multilayers for subquart micron period UV gratings
Authors: Volk J. , Norbert N. , Bársony I.
Published: June 2005

A novel method was presented to prepare porous silicon Bragg grating structures. With this technique the grating period can be easily tuned in a wide range. In the porous silicon multilayer formation there is no theoretical limit for the period to be lowered to even below 100 nm. Both phase and mixed type (amplitude and phase) optical grating are demonstrated. Another unique feature of these structures is, that contrary to the case of commonly used porous silicon layers, here the pores are lying parallel to the wafer surface. This might be a valuable asset e.g. in microfluidic‐type sensor development. The paper discusses design and processing constraints. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Third harmonic generation in a periodic structure with simultaneous linear and nonlinear modulation
Authors: Huang Cheng‐ping , Zhu Yong‐yuan
Published: June 2005

A new scheme for third harmonic generation is proposed, where periodic structures with simultaneous linear and nonlinear modulation are employed. In the quasi‐phase‐matching conditions, the coupling equations are presented and analyzed, and efficient third harmonic generation can be achieved. The results suggest the availability of periodic structures in realizing multiple frequency conversion processes. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic and transport properties of the Co‐doped manganite La0.7Sr0.3Mn1–xCoxO3 (0 ≤ x ≤ 0.5)
Authors: Zhao B. C. , Song W. H. , Ma Y. Q. , Zhang R. L. , Yang J. , Sheng Z. G. , Lu W. J. , Dai J. M. , Sun Y. P.
Published: June 2005

The effect of Co doping on the magnetic and transport properties of La0.7Sr0.3Mn1–xCoxO3 (0 ≤ x ≤ 0.5) is investigated. The Co doping at Mn sites dilutes the double‐exchange interaction between Mn3+ and Mn4+ ions and changes the long‐range ferromagnetic (FM) order of La0.7Sr0.3MnO3 (LSMO) to the spin glass (SG) or cluster glass (CG) state for samples with x ≥ 0.1. For x ≥ 0.3, the paramagnetic (PM) metal to FM metal transition of LSMO disappears and the temperature dependence of resistivity ρ(T) follows semiconducting behavior in the whole measured temperature region with the resistivity increasing by orders of magnitude. An interesting result is that ρ(T) exhibits an obvious anomaly at T* ∼ 100 K, which is ascribed to the spin‐state transition of Co ions. For samples with x = 0.1 and 0.3, magnetoresistance (MR) effects are markedly enhanced in the low‐temperature region compared with undoped LSMO, which is suggested to originate from the appearance of spin‐dependent tunneling magnetoresistance. However, for samples with x = 0.5, the MR effect is suppressed over the entire temperature region measured and an obvious exchange anisotropy phenomenon, characterized by the shift of the hysteresis loop, is also observed, which is ascribed to the marked increase of the antiferromagnetic insulating phase. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Out‐of‐equilibrium nanocrystalline R1–s(Fe, M)5+2s alloys (R = Sm, Pr; M = Co, Si, Ga)
Authors: Bessais L. , Djéga‐Mariadassou C.
Published: June 2005

The out‐of‐equilibrium hexagonal P6/mmm R1–s(Fe, M)5+2s (R = Sm, Pr and M = Co, Si or Ga) intermetallics are obtained by controlled nanocrystallization. A model is presented to explain the structure of the hexagonal phases, which stoichiometry is consistent with Sm(Fe, M)9 and R(Fe, Ti, Co)10. The Curie temperatures increase versus Ga, Si, Co content. The analysis of the Mössbauer spectra leads to monotonous variation of the hyperfine parameters. The refinement of the Mössbauer spectra was performed on the basis of the correlation between Wigner–Seitz cell volumes obtained from X‐ray diffraction results and isomer shifts. The abundance of each magnetic site was calculated by the multinomial distribution law. For a given substituting Co, Si, Ga content, the sequence for the isomer shift in the hexagonal cell is 2e > 3g > 6l. With increasing M content, the isomer shift of the 3g site remains quasi‐constant. Those approaches lead to the location of Si, Ga, Co in 3g site, Ti in 6l site. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of temperature and in‐plane fields on vertical Bloch lines in the walls of the first kind of dumbbell domain
Authors: Liu Suping , Xu Jianping , Guo Gexin , Zhen Congmian , Nie Xiangfu
Published: June 2005

The stability of vertical Bloch lines (VBLs) in the domain walls of the first kind of dumbbell domains (IDs) in garnet bubble films as regards both temperature and in‐plane field is investigated experimentally. It is found that there exists a critical in‐plane field range [Hip(1)(T), Hip(2)(T)] for the VBLs' annihilation in the walls of IDs at various temperatures from room temperature to T0. When Hip ≤ Hip(1)(T), the number of VBLs in the domain walls of IDs is constant; when Hip(1)(T) < Hip < Hip(2)(T), the VBLs in the domain walls of IDs will annihilate gradually and the number of annihilations increases with increasing Hip; when Hip ≥ Hip(2)(T), the VBLs in the domain walls of IDs annihilate completely. Moreover, the range [Hip(1)(T), Hip(2)(T)] decreases with increasing temperature, while the values of Hip(1)(T) and Hip(2)(T) also decrease, and reach zero at T0′ and T0, respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some thoughts on quality
Authors: Constant Paul C.
Published: June 2005

A view of quality is given from inside an independent contract research organization (CRO) that undertakes regulated studies as well as unregulated studies and has as its primary focus on ‘the project’. Focusing on the project brings into play dependency, which means that the success of the project is dependent on the company's Board, its management, and its technical and support staffs. Dependency is a factor that needs to be considered when talking quality. Some project, company, and client dependencies are given. Quality assurance and quality control play important roles in quality operations, but there is more.

Quality needs to be a built‐in aspect, which here is termed ‘quality inherency’, and not an add‐on. Quality should be seen as a quality permeation system powered from the top management position; and as a quality operational system that comprises all technical and business processes, their sub‐processes and interfaces, or linkages. Quality needs to be functional and regularly improved and maintained. Eight major activities are discussed that are needed to achieve quality inherency. Ten processes, their sub‐processes and linkages are presented in a systems diagram as well as summarized in words. The article describes what success means to the client, the research organization's management, the project team member, and the project leader and ends with conclusions. Copyright © 2005 John Wiley & Sons, Ltd.
How to set up and manage quality control and quality assurance
Authors: Visschedijk Myriam , Hendriks Rik , Nuyts Katrien
Published: June 2005

This document provides a general introduction to clarify the differences between quality control (QC) and quality assurance (QA). In addition it serves as a starting point for implementing a quality system approach within an organization. The paper offers practical guidance to the implementation of quality and the importance of QC in its relationship to QA. It can be used in conjunction with the various quality regulations or guidelines. Appendix A provides a table of examples of various activities, which will help guide the user to apply a quality system with both QC and QA aspects. It is important to note, however, that the items listed in the table are only examples and should not be regarded as the only way to set up a QC/QA system. Appendix A is based on the Good Laboratory Practice (GLP) quality system. In conclusion, QC is part of effective project management while QA assesses the effectiveness of the quality systems associated with the overall process. Copyright © 2005 John Wiley & Sons, Ltd.
Who said training in computerized systems validation is boring?
Authors: Brooks Marc , Wetlesen Kjeld
Published: June 2005

This case study describes how ALTANA Pharma provides modular and role‐based training in computerized systems validation. The training is fun while providing all necessary information with hands‐on experience. This is achieved by using many different kinds of exercises to support the learning experience of the presentations in a creative way. Copyright © 2005 John Wiley & Sons, Ltd.
Comments on computational chemistry: From diatomic molecules to large biochemical systems
Authors: Clementi Enrico , Corongiu Giorgina
Published: June 2005

Comments are presented on a few aspects of computational chemistry, considering its evolution and eventual future developments. We also discuss in some detail two topics: first, a new quantum chemical approach that proposes the combination of Hartree–Fock and Heitler–London approximations at the ab initio and at the semi‐empirical level and, second, a sketch for a computational approach aimed at simulations of biological systems with cellular complexity, following an introductory excursion through Newton and Langevin molecular dynamics, microdynamics, and cellular automata. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Experimental investigation of decoherence in maximally entangled mixed states
Authors: Kawamura Minaru , Morimoto Takuji , Kumaya Takashi , Sawae Ryuichi , Takarabe Kenichi , Manmoto Yoshinori
Published: June 2005

Decoherence of the bipartite entangled mixed state in a five‐qubit system has been studied experimentally with liquid‐state nuclear magnetic resonance (NMR). The experimental results indicate that when only two qubits of the five qubits are partially initialized, the decoherence process of the bipartite entangled mixed state is not quantized, as the entanglability is weak. In contrast, when all five qubits are initialized, the decoherence process is quantized, which is understood to indicate that the entanglability is actually strong. From these results, it is conceivable that the entropy of the deviation density matrix is a crucial factor in measuring the entanglement in the liquid‐state NMR quantum computer. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Simulations of metal nanowires
Authors: Elizondo S. L. , Mintmire J. W.
Published: June 2005

First‐principles calculations of the electronic structure of silver infinite nanotubes, chains, and nanowires are reported. For the purpose of this study, the focus is on two specific types of silver nanostructure. We have calculated the electronic structures for the silver (2,3) and the silver (3,4) extended nanostructures. For the (2,3) structure, we modeled the single‐walled tube, and for the (3,4) structure, we modeled the hollow single‐walled tube, as well as the tube with a linear chain inserted along the tube axis. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Convergence radii of five intermolecular perturbation theories applied to the interaction between two hydrogen atoms
Authors: Adams William H.
Published: June 2005

For H2 at infinite separation R we show that the convergence radii can be calculated exactly for two perturbation theories and to high precision for three others. The key in each case is to calculate the lowest energy wave functions belonging to the two possible localizations of the electrons. By focusing on the localization of the electrons the two‐electron eigenproblems are reduced to the solution of 2 one‐electron problems. The wave functions and energies calculated at R = ∞ are used to calculate approximately radii at finite separations. For two theories the dependence of the approximate radii on R is consistent with accurate published results. For two of the perturbation theories a very simple extrapolation procedure is shown to give radii with useful accuracy at R as small as 8 bohr. For the fifth case there are no accurate values known to which our approximate ones may be compared. Why the extrapolation procedure work is explained by a formal analysis based on the assumption of sufficiently large R. Understanding why our method works suggests how radii may be calculated for symmetry‐adapted perturbation theories applied to systems more complex than H2. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Nonlinear response of a deformed oscillator
Authors: Récamier J. , Mochán W. L. , Maytorena J.
Published: June 2005

We analyze the response of a single anharmonic diatomic molecule to a monochromatic time dependent electric field ω(t) and evaluate the temporal evolution of the dipole moment, phase space trajectories, and several transition probabilities as a function of the intensity of the field. We define deformed boson operators A† = f()a†, A = af() in terms of the usual harmonic oscillator creation and annihilation operators a, a†, = a†a and choose the number operator function f() such that the energy spectrum of a harmonic oscillator‐type Hamiltonian written in terms of the deformed operators yields an energy spectrum similar to that of a Morse potential. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Many‐body projector orbitals for electronic structure theory of strongly correlated electrons
Authors: Eriksson O. , Wills J. M. , Colarieti‐Tosti M. , Lebègue S. , Grechnev A.
Published: June 2005

We describe a technique to evaluate projector functions to be used, e.g., in self‐interaction corrected versions of the Kohn–Sham equation (or in the LSDA+U method). The projector functions reproduce by construction the expectation values of spin and orbital moments (or any other property one is interested in) for the atomic many‐body state. We therefore refer to these projector functions as many‐body projector orbitals (MBPO). We describe how, once these projector states have been calculated, one can use them in any electronic structure method for a solid or molecule, to calculate ground‐state properties of materials with strongly correlated states. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Teratogenic compounds of Veratrum californicum (Durand). V. Comparison of cyclopian effects of steroidal alkaloids from the plant and structurally related compounds from other sources
Authors: Keeler Richard F. , Binns Wayne
Published: June 2005

Cyclopamine, and its glycoside alkaloid X, along with jervine and veratrosine, induced cyclopian malformations in offspring born to ewes ingesting these compounds on the fourteenth day of gestation. Other steroidal alkaloids with somewhat similar structures and various other steroidal compounds including certain hormones and steroidal sapogenins did not induce the malformation.
The effect of carbon monoxide on glucose metabolism and growth of rat embryos
Authors: Robkin M. A. , Cockroft D. L.
Published: June 2005

Rat embryos at days 11–12 of gestation cultured for 18 hours in vitro respond to reduced oxygen or to elevated levels of CO. Glucose consumption and lactate production increase while the growth rate decreases. The ratio of lactate produced to glucose consumed increases to values characteristic of earlier, more anaerobic, embryos. It is suggested that most of the energy consumed by the embryo goes to support growth and that the change in glucose metabolism results in a decrease in available energy which decreases the growth rate. The response to reduced oxygen levels is more marked than the response to elevated levels of carbon monoxide and we interpret the result to imply that oxygen transport in these embryos is primarily via solution rather than via combination with hemoglobin.
Campomelic syndrome–possible role of intrauterine viral infection
Authors: Krous Henry F. , Turbeville David F. , Altshuler Geoffrey P.
Published: June 2005

Two infants whose malformations fulfilled the clinical, radiographic and pathologic criteria of campomelic syndrome, were additionally found to have features suggestive of intrauterine viral infection. The presence of hydrocephalus and hydromyelia in both neonates and focal proliferative villitis in the placenta of one suggests that intrauterine viral infection may play a role in the pathogenesis of campomelic syndrome.
Prenatal ethanol exposure in mice: Teratogenic effects
Authors: Randall Carrie L. , Taylor W. Jape
Published: June 2005

C57BL/6J mice were fed a liquid diet in which 17, 25, or 30% of the calories were derived from ethanol from the fifth through the tenth day of gestation. Control mice were fed lab chow or pair‐fed identical diets, except that sucrose substituted isocalorically for ethanol. At term the fetuses were removed and. following fixation, examined by microdissection. The incidence of fetal resorptions and congenital malformations increased in a dose‐related manner. Anomalies included skeletal, neurological, urogenital, and cardiovascular systems. These data indicate that in mice, an alcohol diet which is adequate in vitamins and protein results in increased fetal wastage and birth defects.
The failure of glutamic acid to protect the rat embryo against the action of trypan blue
Authors: Beaudoin Allan R.
Published: June 2005

The effect of L‐glutamic acid on the embryolethal and terato‐genic action of trypan blue was investigated in Wistar albino rats. L‐glutamic acid was either incorporated into the diet, from gestation day 2 to day 20, or suspended in sesame oil and administered by gavage, from gestation day 6 to day 10. The day of finding sperm in the vaginal smear was designated day 0 of pregnancy. A teratogenic dose of trypan blue was injected at day 8 of pregnancy, either intraperitoneally (14 mg/kg maternal body weight) or subcutaneously (160 mg/kg). The amount of glutamic acid consumed, after the injection of trypan blue, ranged from 600 to 1,500 mg/rat/day. Pregnancy was terminated at day 20, and the fetuses were recovered and examined. Glutamic acid failed consistently to protect the rat embryo against the lethal and teratogenic action of trypan blue. These results are in contrast to those obtained in mice. The administration of sesame oil alone was found to cause embryonic death, but not malformations.
The effect of 6‐Aminonicotinamide on energy metabolism in rat embryo neural tube
Authors: McCandless David W. , Scott William J.
Published: June 2005

6‐Aminonicotinamide (6‐AN) is a potent metabolic inhibitor which produces central nervous system malformations when administered to pregnant rats. Since the antimetabolite interferes with energy yielding pathways, the present study was undertaken to determine the effect of maternally administered 6‐AN on energy metabolism of the neural tube in developing embryos. On day 9 of gestation, pregnant rats were injected with 2 mg/kg 6‐AN, and embryos removed 12 or 24 hours later. Glucose, glycogen, lactate, ATP, PCr, and GABA were measured in neural tube sections using fluorometric techniques. Only ATP and PCr showed changes as compared to appropriate controls. These two metabolites were increased 29% and 37%, respectively, by 6‐AN administration. The mechanism of these alterations in metabolites is unclear, but may be related to decreased metabolic demand.
Comparative studies on acetazolamide teratogenesis in pregnant rats, rabbits, and rhesus monkeys
Authors: Scott W. J. , Hirsch K. S. , DeSesso J. M. , Wilson J. G.
Published: June 2005

Acetazolamide produces a characteristic forelimb reduction deformity when administered to pregnant rodents. Past studies indicated that non‐rodent species (rabbit and monkey) are resistant to this effect. The present studies confirmed this fact and demonstrated that transport of acetazolamide into the rabbit embryo was similar to that in sensitive rat embryos. In monkeys, however, the concentrations of acetazolamide within maternal plasma and embryo were much lower than in rats. Carbonic anhydrase activity was also measured since inhibition of this enzyme is the primary pharmacologic effect of acetazolamide. Again the rabbit embryo had carbonic anhydrase specific activity levels similar to that of the rat. Monkey embryos, on the other hand, contained negligible levels of enzyme activity during the presumed sensitive period of development. Thus the resistance of monkey embryos to acetazolamide teratogenesis may be due to low carbonic anhydrase activity and/or the small amount of drug reaching the embryo. No basis for the resistance of rabbit embryos to acetazolamide teratogenesis was uncovered.
Splayleg: A spontaneous limb defect in rabbits. Genetics, gross anatomy, and microscopy
Authors: Joosten Harrie F. P. , Wirtz Peter , Verbeek Herman O. F. , Hoekstra Arend
Published: June 2005

A limb defect in rabbits known as splayleg arose in a closed breeding colony of Dutch rabbits. Since the causes of this postural deformity are not fully understood, an effort was made to clarify the mode of inheritance and the etiology of the disease.

Pedigree analysis and genetic mating tests showed that, in contrast to published reports, the disease is not determined by a single recessive gene with complete expressivity. The underlying genetic system is composed of one recessive gene with reduced expressivity or of more genes with the probable involvement of environmental factors.

Femurs of abnormal limbs displayed endotorsion of the shaft and anteversion of the neck as the main features. Endotorsion of the femur was associated with exotorsion of the tibia. Dislocation of the hip was not observed. There was no abnormal laxity of the joint capsule or the ligamentum teres. Only minor differences in the acetabulum between control and splayleg rabbits were observed.

Enzyme histochemistry and electron microscopy of the gluteus medius, adductor longus‐ and magnus, sartorius, gracilis, and semitendinosus muscles and the femoral, peroneal, and tibial nerves did not reveal any qualitative differences between splayleg and control rabbits. A study on muscle fiber diameter showed that fibers of splayleg animals were in general smaller, pa ticularly in the semitendinosus. Atypical mitochondria of muscles were observed in all rabbits, but more frequently in splayleg animals.

A hypothesis is presented in which imbalanced development of the neural, muscular and skeletal systems of the limb is the primary defect. This results in torsion of the femur. It depends on the degree of femoral torsion and the capacity of the young rabbit for compensation by exorotation of the limb in the hip whether a persistant splayleg posture will develop.
Pathogenicity of influenza A virus in ependymal organ culture
Authors: Kohn D. F. , Chinookoswong N. , Magill L. S.
Published: June 2005

Ependymal organ culture was used as a model to study the effect of influenza A virus on the ciliated ependyma of the rat. One‐square‐millimeter portions of cerebellum from newborn rats were harvested in roller tubes containing Ham's F‐12 medium, calf serum, and glutamine. Ciliary activity was monitored by stereomicroscopy and, after vigorous ciliary motion was established, tubes were inoculated with 0.1 ml of an inoculum containing 35 plaque‐forming units (PFU) of neurotropic influenza A virus (WSN strain). Explants were examined by scanning electron microscopy (SEM) at 2 and 7 days and by transmission electron microscopy (TEM) at 7 days. When compared to noninfected controls, SEM showed that at 2 days the density of microvilli and cilia was decreased in influenza A virus‐infected explants. At 7 days the ependymal cells were nearly denuded of cilia and microvilli, and macrophagelike cells were frequently resting upon the ependymal surface. TEM showed numerous viral particles, both budding from the cell surface and located extracellularly near the cell surface.
A genetic factor controlling morphogenesis of the laryngotracheo‐esophageal complex in the mouse
Authors: Essien Francine B. , Maderious Alan
Published: June 2005

A new autosomal, recessive lethal mutation in the mouse causes failure of division of the embryonic foregut into totally separate digestive and respiratory ducts. The newborn homozygote has a cleft that extends between the laryngotracheal and esophageal tubes, allowing excessive air to pass into the stomach and subsequently into the peritoneal cavity. This mutation has been designated lec (laryngotracheo‐esophageal cleft). The common region shared by the respiratory and digestive tubes has features characteristic of both structures. Development of cartilage around the laryngotracheo‐esophageal complex is also affected in the mutant.
Unusual cardiac malformations in splenogonadal fusion‐peromelia syndrome: Relationship to normal development
Authors: Loomis Karl F. , Moore G. William , Hutchins Grover M.
Published: June 2005

A male newborn infant, studied at autopsy, showed continuous splenogonadal fusion and severe peromelia associated with an unusual, possibly unique, cardiac malformation complex. The cardiac lesions included multiple right ventricular diverticula, tricuspid atresia, mitral to semilunar valve discontinuity, and absent muscular outflow tract septum. Tabulation of the time of appearance of relevant anatomic features in 351 normal human embryos of Carnegie stages 9 through 23 showed that the teratogenic influence in the present case probably occurred by stages 16–17. The nature and distribution of lesions observed suggest that proliferating undifferentiated mesenchme was the target of the unknown injury.
Toxic and teratologic effects of caffeine on explanted early chick embryos
Authors: Lee H. , Nagele R. G. , Pietrolungo J. F.
Published: June 2005

The toxic and teratologic effects of caffeine on chick embryos ex‐planted at stages 4–7 and cultured for 19–22 hours were investigated. Caffeine, at 200–300 μg/ml, significantly increased the incidence of neural tube defects regardless of the developmental stage at treatment. Concentrations of 500 μg/ml or higher inhibited morphogenesis of nearly all organ primordia. In general, the effects of caffeine were concentration dependent and younger embryos were more susceptible to treatment than their older counterparts. Microscopic studies confirmed that the developing neuroepithelium was most sensitive to treatment. Caffeine, at concentrations sufficient to inhibit neural tube closure, caused no apparent alteration in the ultrastructure of cellular components except that apical microfilament bundles were thinner and less conspicuous than usual. Furthermore, caffeine (400 μg/ml) selectively inhibited uplifting of neural folds (and hence, closure of the neural tube) in embryos explanted at stage 8 and cultured for 4–6 and 16 hours. Affected neuroepithelial cells lacked the typical bottle‐shaped characteristic and folded apical surfaces. Overall results of this study suggest that caffeine causes neural tube defects, at least in part, through its inhibitory action on the contractile activity of apical microfilament bundles in developing neuroepithelial cells.
Ontogeny of suckling behavior in rats prenatally exposed to alcohol
Authors: Chen Jaw‐Sy , Driscoll Cynthia D. , Riley Edward P.
Published: June 2005

The effect of prenatal alcohol exposure on nipple attachment behavior was studied at a number of ages in rat pups whose mothers consumed liquid diets containing 35% or 0% ethanol‐derived calories (EDC) or standard lab chow during pregnancy. In the first experiment, nondeprived pups were tested in groups of three (one from each of the prenatal treatment groups) for nipple attachment to an anesthetized lab chow dam. The second experiment examined the influence of the type of test dam (35% EDC, 0%EDC, or lab chow) on nipple attachment behavior. Finally, experiment three evaluated the possibility that the data from the preceeding experiments were the result of either testing the offspring in triads or alcohol‐induced alterations in maternal behavior. Rat pups from all three groups reared by their biological mothers and a group of 35% EDC offspring fosterd at birth to lab chow surrogate mothers were tested alone rather than in triads. The data from all three experiments clearly indicated an age‐related pattern of nipple attachment behavior; the latency to attach was shortest in 6‐ to 12‐day‐old pups and increased rapidly from 13 to 21 days of age. Prenatal exposure to alcohol significantly increased the latency to attach to the nipple and the rank order of attachment at the younger ages (three to nine days of age) but not in the older animals. Also, the prenatal effect of alcohol was independent of the type of dam to which testing was conducted, the social interaction involved in testing triads, or fostering procedures. These results suggest that prenatal alcohol exposure can interfere with the development of normal suckling behavior, which might influence normal growth.
The pathogenesis of brain abnormalities in the fetal alcohol syndrome: An integrating hypothesis
Authors: Kennedy L. A.
Published: June 2005

The most obvious characteristics of the fetal alcohol syndrome are a cluster of minor, physical malformations that are rather nonspecific and that vary greatly in the frequency and severity of expression. The most common characteristrics are general body and organ growth deficits, including microcephaly. The most debilitating characteristics, however, are central nervous system (CNS) dysfunctions, such as behavioral and intellectual impairments, which appear to be closely related to the growth deficits. The mechanisms whereby alcohol exerts its deleterious effects on intrauterine growth and development are being intensively investigated. Because of its pharmacological properties, maternal consumption of alcohol is associated with widespread effects throughout the maternal‐placental‐fetal organism, many of which can secondarily alter the in utero environment. Both direct and indirect mechanisms are discussed with respect to their contribution to alcoholrelated effects on embryofetal growth and development. It is suggested that impairment in the protein synthetic machinery, resulting in cellular growth restriction at critical periods of development is the common mechanism underlying alcohol's teratogenicity. Because the development of the CNS is so prolonged and complex compared to other organ systems, it is exquisitely vulnerable to derangement throughout pregnancy.
The influence of deoxycytidine monophosphate (dCMP) on the cytotoxicity of hydroxyurea in the embryonic spinal cord of the mouse
Authors: Herken R.
Published: June 2005

On day 10 of pregnancy NMRI mice received an intraperitoneal injection of either 500 mg/kg hydroxyurea (HU) or 500 mg/kg HU plus 500, 700, 800, or 900 mg/kg deoxycytidine monophosphate (dCMP). Three hours after application of the substances, the animals received 5 μCi/g 3Hthymidine i.p. One hour later the animals were sacrificed and the embryos were removed. Autoradiographs of the embryos served to determine the percentage of necroses, labelled necroses, mitoses, labelled mitoses, and labelled neuroepithelial cells of the spinal cord. Optimal inhibition of HU effects was achieved by application of 700 mg/kg dCMP. The cytotoxic effects of HU on neuroepithelial cells could be partially but not completely inhibited by simultaneous application of dCMP. The duration of HU‐induced DNA synthesis inhibition was shortened after simultaneous dCMP application. A strong increase of the labelling index and shortening of the G2‐phase duration of neuroepithelial cells after simultaneous application of HU and dCMP was striking as compared to the results obtained from untreated or HU‐treated animals.
Ultrastructural changes in the neural tube of 10‐day‐old mouse embryos exposed to colchicine and hydroxyurea
Authors: Herken Rainer
Published: June 2005

The ultrastructural changes in the neural tube of 10‐day‐old mouse embryos were investigated between 1.5 hr and 4 hr after application of either 1 mg/kg colchicine (Col) or 500 mg/kg hydroxyurea (HU) or simultaneous application of both substances. During the investigated period, the shape of the nuclei of the neuroepithelial cells had changed from elongated to round after Col application. The chromatin in the nuclei was condensed and arranged in clusters. A breakdown of polysomes into ribosomes and an enlargement of the rough ER was observed in the cytoplasm. At the luminal surface, bleb‐like cytoplasmic processes of the neuroepithelial cells containing monoribosomes protruded into the lumen. No cell necroses were visible in the neural tube after Col application. A condensation of chromatin in the nuclei of some neuroepithelial cells was visible 1.5 hr after HU application. Shortly thereafter, cell necroses appeared in the neural tube and 4 hr after HU application the entire spinal cord was strongly damaged. After simultaneous application of Col and HU, the ultrastructural changes in the neuroepithelial cells of the neural tube did not differ from the results obtained after Col application alone. In contrast to the results obtained after HU application alone, no necroses occurred after simultaneous application of Col and HU.
Effects of streptozotocin‐induced diabetes on fetal development of the rat
Authors: Giavini E. , Broccia M. L. , Prati M. , Roversi G. D. , Vismara C.
Published: June 2005

The purpose of this study was to determine whether or not in rats with experimentally induced diabetes there is an increased frequency of congenital malformations; data in the literature are not consistent on this point. Virgin CD females rats were injected with 40–50 mg/kg streptozotocin (Stz) before mating (SIBM group) or on the first day of pregnancy (SI1). Both SIBM and SI1 females were divided into two groups according to their blood glucose levels: severaly diabetic (SD, > 300 mg%) and mildly diabetic (MD, 120–250 mg%). Food and water consumption by the control and MD groups were the same, but the SD females developed polyphagia, polyuria, and polydypsia, which continued to increase throughout pregnancy, as did the blood glucose levels. All the MD females mated and carried to term. In SD females both frequency of mating and fertility were only slightly lower than in the controls. All the females were killed on the 21st day of pregnancy. Pre‐ and postimplantation losses were the same for diabetic and control rats, but SIBM‐SD females ovulated less than other groups. Weights of fetuses of SD dams were lower and blood sugar levels higher than those of the other groups. The placentas of SD rats were significantly heavier and there was cystic degeneration of spongiosa. The incidence of major malformations was minimal ( ∼ 2%) in fetuses of SD females and there were none at all in controls or MD females. In conclusion, our data are in agreement with those of other investigators who have found that rats with experimentally induced diabetes have smaller fetuses and increased placental weight. But our data do not show any increase in incidences of malformations or of fetal loss, which have been reported by some groups. One basis for this disagreement might be the differences in the composition of the diets, especially in mineral salt content. We are currently investigating this possibility.
Anomalous neural differentiation induced by 5‐bromo‐2′‐deoxyuridine during organogenesis in the rat
Authors: Biggers William J. , Barnea Eytan R. , Sanyal Mrinal K.
Published: June 2005

The influence of 5‐bromo‐2′‐deoxyuridine (BrdU) on rat embryo development and neurogenesis was investigated using a rat conceptus culture system during organogenesis (pregnancy days 10–13). The embryos and visceral yolk sacs of conceptuses cultured with BrdU were examined for overall growth, morphological anomalies, incorporation of radiolabeled BrdU into DNA, and neurotransmitter enzyme activities in embryos. In addition, neural tubes from cultured whole embryos were isolated and mechanically dissociated into fragments and cultured again to assess neural cell differentiation into neuron‐like cells. BrdU was found to incorporate differentially into embryonic and visceral yolk sac DNA with simultaneous stage‐specific retardation and anomalous organogenesis in proportion to the increasing concentrations used. Neural tube differentiation of cultured embryos was markedly altered, and there were morphologically distinct neural anomalies. The neurite outgrowth from neuroblast cells (type 1) of explanted spinal neural tube fragments from BrdU‐treated embryos was markedly reduced in length and number compared to those from similar areas of embryos grown without BrdU. In contrast, BrdU at the same doses did not affect differentiation of a number of neural tissue‐related enzymes. These results indicate that BrdU incorporation into DNA of primordial embryonic cells significantly affects neurogenesis and differentiation of neurites from neuroblasts, which is a specific neural cytodifferentiation characteristic of neuronal cells.
Subcellular effects of experimental oligohydramnios on the developing rat limb
Authors: Houben Jean‐Jacques , Huygens R.
Published: June 2005

In the rat, the development of the limb bud can be impaired by amniotic puncture. Selective haemorrhages are observed within 1 hour of the treatment. An ultrastructural analysis was undertaken to uncover the cytological changes associated with these haemorrhages. The earliest effect of oligohydramnios is the appearance of a periendothelial oedema which separates the mesodermal cellular processes from the endothelial basal lamina. The loosening of the latter and the distortion of the endothelial cells occur almost simultaneously. Subsequent damage of the mesodermal cells ensues, the ectoderm and the preskeletal condensations remaining unaffected. Only general damage of the embryo affecting all tissues will lead to the complete necrosis of the limb bud and even to foetal death. The great variability of skeletal defects observed in amniocentesis syndrome can be accounted for by the higher resistance of the differentiating cells to a decrease in blood supply.
Steroid contraceptive use and pregnancy outcome
Authors: Pardthaisong Tieng , Gray Ronald H. , McDaniel Edwin B. , Chandacham Arida
Published: June 2005

Contraceptive use in relation to pregnancy outcome was studied in 8,816 births in Chiang Mai, northern Thailand, by examination of newborn infants and interviews with their mothers. Four thousand twenty‐three women used no contraception before the index pregnancy, 1,229 used the injectable contraceptive Depo Provera (DMPA), and 3,038 used oral contraceptives prior to or during pregnancy. No differences were observed between these groups with respect to still births, multiple pregnancies, and birthweight. Women who used oral contraceptives had unexpectedly low rates of major defects and may have been affected by self‐selection bias, whereas the noncontraceptors had rates similar to other populations. There was a significantly increased association of polysyndactyly among infants of DMPA users relative to the other groups, which was most pronounced in offspring of women under age 30 years, and persisted after exclusion of subjects with a family history or infants with multiple abnormalities. However, in five out of the ten polysyndactyly, cases, the last injection of DMPA occurred more than 9 months before conception, and only three cases had definite gestational exposure. The association of chromosomal anomalies was also significantly increased in infants of mothers who used DMPA. The unrelated nature of these defects, the lack of confirmation from other studies, the distant preconceptional exposure to DMPA in many cases, and chance effects due to multiple statistical comparisons make a causal association unlikely. Other birth defects that had been previously reported in some publications to be associated with progestational steroid exposure, such as neural tube defects, heart malformations, and limb reduction defects, were not found in this study. Further research should evaluate in detail the type and incidence of syndactyly or chromosomal aberrations in exposed groups and appropriate control populations.
Evaluation of the bioeffects of prenatal ultrasound exposure in the cynomolgus macaque (Macaca fascicularis): I. Neonatal/infant observations
Authors: Tarantal A. F. , Hendrickx A. G.
Published: June 2005

The frequency of use of ultrasonography for evaluating the developing embryo/fetus has continued to rise although the possible risks from exposure still remain uncertain. The cynomolgus macaque (Macaca fascicularis) is currently being used in our laboratory as a model to assess these risks. In utero exposure was performed utilizing a commercial real‐time mechanical sector scanner with a 7.5 MHz scanhead (ATL, MK 600). Maximum acoustic power output for this unit is as follows: I(SPTA) = 12.0 mW/cm2, I(SPPA) = 98 W/cm2, and Im = 137 W/cm2. Animals exposed to ultrasound (N = 16) were scanned five times weekly on gestational days (GD) 21–35±2 for 10 minutes/exam (m/e), three times weekly on GD 36–60±2 for 10 m/e, and once weekly on GD 61–150±2 for 20 m/e. Controls (N = 14) were “scanned” with the unit placed on standby. Assessment of simian Apgar scores at 1, 5, and 10 minutes of life revealed higher scores for treated animals at 10 minutes (P⩽0.045); greater scores in muscle tone (P±0.013) and color (P±0.016) were observed. Evaluation of morphometrics at birth including weight, biparietal diameter, occipitofrontal diameter, head circumference, hand and foot lengths, humerus and femur lengths, arm circumference, chest circumference, tail length, skinfold thickness, and crown‐rump length (CRL) indicated a significant reduction in only two parameters, birth weight (P±0.027) and CRL (P±0.033). Hematologic analysis at 2±1, 9±1, and 16±1 days of life revealed a significant difference in white blood cell counts (WBCs). Treated animals displayed lower WBCs with reductions in numbers of segmented neutrophils and monocytes at all ages observed. Hematologic differences were not significant by 5–6 months of age. No abortions, gross malformations, or stillbirths were observed in the exposed animals.