bluuebunny/crossref_metadata_2025 huggingface dataset:
Moderating Effects of Psychological Job Strain on the Relationship between Working Hours and Health: An Examination of White‐Collar Workers Employed by a Japanese Manufacturing Company
Authors: Tarumi Kimio , Hagihara Akihito , Morimoto Kanehisa
Published: October 2004

Moderating Effects of Psychological Job Strain on the Relationship between Working Hours and Health: An Examination of White‐Collar Workers Employed by a Japanese Manufacturing Company: Kimio Tarumi, et al. Section of Postgraduates Guidance, University of Occupational and Environmental Health—The effects of working hours on health were examined taking psychological job strain into account. White‐collar workers employed at the main office of a Japanese manufacturing company provided data for analysis done in 1997. The eligible subjects were 286 workers aged 20–39. Causal relationships between working hours, health, and psychological job strain were examined by covariance structure analyses. The main findings were as follows: Not only working hours but also sleeping hours and vacations affected the workers’ effort to deal with work as a work‐related hour factor. Decision authority and skill discretion of Karasek's psychological job strain items significantly constituted a discretion in the work factor, and this factor moderated the effects of the work‐related hour factor on health. The effects of psychological job strain, especially discretion, must always be taken into account in examinations of working hours and health.
Effects of Prednisolone and Complex of Vitamin B1, B2, B6 and B12 on Organophosphorus Compound‐Induced Delayed Neurotoxicity
Authors: Piao Fengyuan , Ma Ning , Yamamoto Hidetaka , Yamauchi Toru , Yokoyama Kazuhito
Published: October 2004

Effects of Complex of Prednisolone and Vitamin B1, B2, B6 and B12 on Organophosphorus Compound‐Induced Delayed Neurotoxicity: Fengyuan Piao, et al. Department of Public Health, School of Medicine, Mie University—Protective effects of prednisolone as a synthetic adrenal cortical hormone and complex of vitamin B1, B2, B6 and B12 on organophosphorus compound‐induced delayed neurotoxicity (OPIDN) caused by leptophos and tri‐ocresyl phosphate (TOCP) as organophosphates (OPs) were examined. Nine groups of hens (six for each) were used. Eight groups received intravenous injection of 30 mg/kg of leptophos or 40 mg/kg of TOCP (four groups in each). Among them, three groups which received leptophos were given (p.o.) predonisolone (2 mg/body), vitamin B complex (25 mg/body) or both 3 h after OPs injection and then every day for 15 d (one group for each); the same treatment was performed on three groups which received TOCP. The remaining one group served as controls. It was observed that delayed neuropathy induced by OPs could not be resisted completely by the treatment with prednisolone or vitamin B complex, but clinical signs of OPIDN and pathological changes in hens that received these two protective agents after OPs were less severe than those in hens that received only OPs. Of these groups, the improvement in clinical signs was best shown in hens that received the both two protective agents. In addition, improvement in clinical signs among the hens that did not deteriorate to paralysis was observed. In particular, those which developed mild ataxia recovered well. It is indicated that combining administration of prednisolone and vitamin B complex early before clinical signs are manifest is effective in alleviating neuropathy. It is also suggested that recovery or good prognosis will be expected, as long as progression of the clinical signs is prevented before paralysis develops in delayed neuropathy.
Liver Cancer Risk in Japanese Male Dentists: A Long‐Term Retrospective Cohort Study
Authors: Tanaka Hideo , Nishio Nobuhiro , Tokunaga Rikio , Tsukuma Hideaki
Published: October 2004

Liver Cancer Risk in Japanese Male Dentists: A Long‐Term Retrospective Cohort Study: Hideo Tanaka, et al. Department of Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases—It has been speculated that dentists are at high risk for occupational exposure to bloodborne viruses such as hepatitis B and hepatitis C viruses. To assess the risk of the development of liver cancer among Japanese male dentists, we conducted a retrospective cohort study on 3,314 dentists of the Osaka Dental Association who were members between 1964 and 1985, the year before HBV immunization became available. By linking to the Osaka Cancer Registry, we found that during the period of 1964–1997, 36 of the dentists were diagnosed with liver cancer over a mean follow‐up of 23.6 yr. The observed number of liver cancer cases was compared with the expected number, which was calculated by multiplying the number of person‐years at risk by the corresponding age‐ and calendar timespecific incidence rate from the Osaka Cancer Registry data. The male dentists had a significantly lower risk of developing liver cancer than the general population of Osaka (O/E=0.71, 95% CI=0.50–0.98). On subcategorical analysis by birth year or duration of follow‐up, there was no significantly increased risk of developing liver cancer among the dentists. Contrary to our expectation, our findings indicate that Japanese dentists were not at increased risk of developing liver cancer compared with the general population.
Physiological Effect of Vibrations on Tractor Drivers under Variable Ploughing Conditions
Authors: Muzammil Mohammad , Siddiqui Saad S. , Hasan Faisal
Published: October 2004

Physiological Effect of Vibrations on Tractor Drivers under Variable Ploughing Conditions: Mohammad Muzammil, et al. Department of Mechanical Engineering, Ergonomics Laboratory, Faculty of Engineering & Technology, Aligarh Muslim University, India—The vibration conditions to which tractor operators are subjected are complex and varied with multi axis translation and rotational vibration inputs to different parts of the body. Working under such conditions may lead to human fatigue and other driving related hazards. The present research was carried out to study the operators under varying conditions of vibration while driving a tractor with and without farm equipment on different fields. Test runs were conducted in wet and dry fields to determine the levels of vibration generated at different engine speeds. On the basis of this study three levels of vibration namely 2.5, 3.5 and 5.0 m/s2 were selected. Five subjects, all males, with no experience in the field of tractor driving participated in the study. The data were analyzed on the basis of three factor repeated measure kind of experimental design. The results showed that the main effects of farm equipment and the vibration level were statistically significant but the effect of field type was found to be statistically non‐significant. The results of the study call upon the ergonomists to design and develop a tractor where the driver may be relieved of vibration induced stresses. Front loading of farm equipment is recommended for improved visibility and better working posture.
Charged‐particle Optics
Authors: Nolen Jerry A. , Portillo Mauricio
Published: October 2004

The emphasis of this article is on the common fundamentals and techniques on which the wide variety of different beam‐optical devices are based. It should give the reader the necessary background to understand the principles of the actual devices described elsewhere in more advanced treatments. Along with the qualitative description of the basic building blocks of charged particle beam optics, enough selected references to monographs and research reports are given to guide the interested reader towards more in‐depth studies. Relatively few references to original research papers are given, but extensive bibliographies are included in the listed review articles and textbooks. Topics introduced include: single‐particle motion of charged particles in electric and magnetic fields, sources of charged particles, beam handling and transport, magnetic and electric deflection systems, aberrations of charged particle optical systems, and the mathematics of matrix methods for charged particle optical simulation.
Lasers, Gas
Authors: Eden J. Gary , Eichler Jürgen
Published: October 2004

This article reviews the characteristics of gas lasers that are chiefly responsible for their effectiveness as both scientific and industrial tool. The basic principles common to operation of all gas lasers and a few of their general properties are discussed. The lasers are categorized according to the pumping mechanisms: electron‐impact excitation (copper and gold laser, Ar‐ and Kr‐ion lasers), excitation transfer (He–Ne laser, He–Cd laser, CO2laser), reactive collision lasers (excimer laser (ArF, KrF, XeCl, XeF, F2), chemical lasers (HF, COIL)), and other lasers in the far infrared, ultraviolet, and soft X‐ray region. Selected applications of pulsed and continuous gas lasers are presented in material processing, marking and laser evaporation, microlithography, photochemical processing, stereolithography, and medicine.
Lasers, Industrial Use of
Authors: Roessler David M. , Steen Wiliam M.
Published: October 2004

Lasers are capable of generating large and controllable quantities of optical energy and delivering it at intensities sufficient to produce permanent changes in materials. This new form of industrial energy has led to a wide range of laser‐based manufacturing processes, such as cutting, welding, surface treatment, bending, cleaning, rapid prototyping, direct casting, and so on. Although these form the focus of this section, it must be noted that there are many other industrial applications that are not covered here, ranging from communications and compact disc players to medicine and metrology. Although laser‐materials processing has developed and grown rapidly in the last few decades, it is still far from being a mature technology. New lasers continue to be developed as do new applications.
Diodes, Light‐emitting
Authors: Gardner Nathan F. , George Craford M. , Steranka Frank M.
Published: October 2004

A light‐emitting diode (LED) is a semiconductor device that emits monochromatic ultraviolet, visible, or infrared electromagnetic radiation when an electric current is passed through it. The semiconductor material is a compound or alloy of elements from columns III and V of the periodic table. Light‐emitting diodes are compact, mechanically rugged, energy efficient, are of low voltage, and have long operating lifetimes. For colored lighting applications, the efficiency of LEDs far exceeds that of filtered incandescent sources and they are becoming the dominant technology. LEDs are widely used as indicator lights, for backlighting small displays in electronic equipment, in exterior and interior lighting of automobiles, in large‐area full‐color displays, and for data communication. LEDs will be used for general white‐light illumination purposes to the extent that the energy efficiency improves and higher‐power, higher‐flux devices become available.
Optical Components and Systems
Authors: Litfin Gerd , Schuhmann Rainer
Published: October 2004

This article gives an overview of geometrical optics and includes the most important formulas as well as a few optical systems of general interest.

It describes the main optical components such as lenses, mirrors, plane plates, prisms, fibers, and thin films and their influence on light beams as light propagation and polarization. The principles of reflection and refraction are discussed as well as the optical imaging based on first‐order optics. The basic formulas are given.

The discussion on plano‐optics considers the spectral properties of filters and prisms, the change of image orientation by a single prism and prism systems, beam splitting, and polarization effects due to birefringence of crystal components. Total internal reflection can guide light in optical fibers. Different fiber types are described.

Besides single components as best‐form lenses and doublets, only multielement optical systems can meet the requirements of different imaging applications. Therefore, a selection of well‐known optical systems considering their main properties is described. This includes camera lenses, microscopes, and more sophisticated optical systems as well as a short side‐glance on the requirements of interferometers that cannot be described by the geometrical optics approach.

Furthermore, a section on optical bench systems summarizes the necessary support of optics by mechanical components. This includes bench profiles and structural systems using the micro bench.
Optical Instrumentation
Authors: Hoeschen Dietmar , Mirandé Werner
Published: October 2004

Optical instrumentation is based on phenomena caused by optical radiation. In this article, optical radiation is limited to a wavelength range between 200 nm and 50 µm. After a short survey about the historical development of optical instrumentation, phenomena resulting from the various characteristics of optical radiation, as for instance, a wave or a particle, are considered. Based on the wavelength character, optical instrumentation used for interferometry, colorimetry, spectroscopy, diffraction, imaging, and optical frequency standards is treated. The interaction of optical radiation with matter is used in refractometry, in polarimetry, for studying matter with ultrashort pulses of radiation, and for processing matter with radiation of high‐energy density. Finally, the particle character is considered to be used for fields such as radiometry and energy conversion.
Optical and Laser Scanning Technology
Authors: Beiser Leo
Published: October 2004

This article consolidates optical and laser scanning technology and its utilization. The dominant scanning devices and techniques are appraised, including the polygon and holographic scanners, galvanometer and resonant scanners, fast steering mirrors, acousto‐optic and electro‐optic deflectors, and new agile beam steering methods. Also addressed are their application, classification, architecture, symmetry factors, image rotation, duty cycle, scanned resolution, optical power transfer, and cross‐scan error reduction.

Two complementary fields are presented: (Active) Laser Scanning and (Passive) Remote Sensing. While scanning devices may appear interchangeable, significant distinctions relate to the filling of their optical apertures and the use of spectrally dispersive optics. Laser scanning, having a controlled intensity distribution, projects moving illumination on very small portions of an area with functionally coherent radiation, allowing the use of diffractive optics. In contrast, remote sensing transfers spectrally broad radiation scattered from a distant object field, imaged and collected through a scanning aperture that directs the sampled radiation to a fixed detector. The scanner, intimately associated with its objective lens, is developed as oriented within a conjugate optical imaging system. Active laser radiation is thereby transferred selectively to its image. In passive sensing, ray directions are reversed, representing the conjugate transfer of radiation from remote object points back to the detector.
Linear Optics
Authors: Dorsel Andreas
Published: October 2004

This article gives a condensed overview of the key areas of linear optics, addressing fundamental aspects of light propagation and their application. After first principles like the speed of light and the laws of reflection and refraction, as well as the Fresnel formulas for transmission and reflection, total internal reflection, and linear absorption, geometric optics is briefly covered with the basic descriptions of imaging using simple mirrors and lenses. As examples of simple optical instruments, the single‐lens eye, the magnifier and microscope, as well as astronomical and terrestrial telescopes are included. Subsequently, phase‐dependent phenomena like interference and diffraction are described, including examples of a few basic cases that can be used to address more complex cases. Anisotropic media and polarization effects are covered next, including brief notes on electro‐optic, magneto‐optic, and acousto‐optic effects. Finally, examples of recent developments are described as an outlook to contemporary optics work.
Spectrometers,X‐ray
Authors: Markert Thomas H. , Förster Eckhart
Published: October 2004

X‐ray spectrometers are used in many fields of pure and applied science as well as in industry. They are employed to investigate cosmic and laboratory high‐temperature plasmas where a high spectral resolution in the emission spectra is required. Commercial X‐ray spectrometers register X‐ray fluorescence of a sample under X‐ray irradiation or electron bombardment. In this case, registration of a wide spectral range with moderate resolution is performed to obtain the elemental composition of a sample.

The main experimental parameters of a spectrometer are its resolving power, sensitivity, and breadth of spectral coverage. Dispersive spectrometers that use X‐ray crystal diffraction to widen the incident spectrum have great advantages in spectral resolution. To raise their sensitivity, different X‐ray optics such as grazing incident mirrors, polycapillaries, bent gratings, or bent crystals are implemented. Nondispersive spectrometers that convert the energy of an incident X ray into a number of “particles” (electron–hole pairs, electron–ion pairs, phonons, etc.) have a moderate spectral resolution, good sensitivity, and wide breadth of spectral coverage. Recently developed microcalorimeters need a complex cryogenic system for the detector but have a competitive spectral resolution as dispersive spectrometers.
Spectroscopy, Ultrafast
Authors: Dantus Marcos , Gross Peter
Published: October 2004

Spectroscopy studies the interaction between light and matter. Ultrafast spectroscopy involves the study of this interaction using temporally short light pulses capable of probing directly the dynamics of the system rather than its energy levels. Rapid advances in laser technology over the past decades have resulted in the generation of pulses with femtosecond time duration (1fs = 10−15 s). These lasers are being used to interrogate solids, liquids, and gases to learn about the dynamics of matter (electrons, atoms, molecules) following laser excitation. The description given here explains how an ultrashort laser pulse excites a coherent superposition of energy levels, and how this excitation can be followed in time. To date, ultrafast spectroscopy has been used to measure processes in diverse fields, for example, to measure the time it takes to break or form a chemical bond; to measure the temporal response of molecules involved in photosynthesis, or vision; and to measure the flow of charge in semiconductors. Examples of these kinds of studies illustrate this presentation.
Spectrometers, Ultraviolet and Visible Light
Authors: Hardwick John L.
Published: October 2004

A wide variety of instruments exist for recording the intensity of light as a function of wavelength. In the visible and ultraviolet regions of the spectrum, these include dispersive spectrometers (based on gratings and prisms) and nondispersive spectrometers (usually interferometric in nature). A discussion of the main kinds of visible and ultraviolet spectrometers is given along with their advantages and drawbacks in terms of resolution, accuracy, efficiency, and ease of use. Considerations for choosing the design of an optical spectrometer are outlined, and the main aberrations associated with common optical designs are discussed.
Color Vision
Authors: Webster Michael A.
Published: October 2004

Color provides important cues to both the nature and location of objects in our environment. Normal human color vision is trichromatic because it depends on sampling the light spectrum with three classes of cone photoreceptor maximally sensitive to short, medium, or long wavelengths. Most forms of color‐blindness are genetic and result from losses or alterations of the cone photopigments. Postreceptoral neurons sum the cone signals to form luminance‐sensitive channels and contrast them to form color‐opponent channels. Color opponency is suggested by both physiology and color appearance, though higher stages of color coding in the visual system remain unclear. Perceived color is strongly affected by adaptation to colors viewed previously and by induction from surrounding colors. These processes help normalize the response to color and contribute to color constancy for objects viewed in different lighting.
Colorimetry
Authors: Stockman Andrew
Published: October 2004

Colorimetry is concerned with the measurement and numerical specification of the color of visual stimuli. Color depends on the underlying biology of the human visual system, and in the first instance on the spectral properties of the three types of light‐sensitive cone photoreceptors in the eye. Color and color matches are trichromatic, meaning they can be specified by three variables that are linearly related to the outputs of the three cone types. The primary aim of colorimetry is to be able to specify those variables for lights of any spectral composition.
Lidar (Laser Radar)
Authors: Argall P. S. , Sica R. J.
Published: October 2004

Lidar is an active remote sensing technique similar in principle to radar, except that it utilizes light rather than radio waves. Lidar finds applications in many areas, including atmospheric and oceanic research, digital mapping, chemical and biological agent detection, speed measurement, and targeting. This chapter describes the principles of lidar and provides examples of the application of lidar in measuring the properties of the Earth's atmosphere.
Optical Metrology
Authors: deGroot Peter
Published: October 2004

The article reviews the optical measurement of shape, texture, geometric dimensions, and position of objects, with applications ranging from stage metrology to optical comparators. An emphasis is placed on mechanical and geometric metrology, as opposed to remote sensing. The underlying technologies rely therefore on interferometry, triangulation, and time of flight to determine distances and lengths, as well as those object features accessible to length measurement, including, for example, form and roughness.
Photonics
Authors: King Terence A.
Published: October 2004

Photonics concerns the generation, transmission, manipulation, and interactions of light and its applications in many varied areas in research, industry, and everyday life. This general overview of photonics draws special attention to the development of laser sources, semiconductor optics, fiber optics, and photonic techniques such as ultrafast pulse generation. The wide range of applications is reviewed with particular attention to information technology and optical communications, optical information storage, displays, sensors, and industrial applications. The rapidly growing field of applications in biophotonics and biomedical optics is also emphasized with new techniques of optical coherence tomography (OCT) and optical trapping.
Wave Optics
Authors: Dallas William J.
Published: October 2004

Narrowly interpreted, the term
wave optics
encompasses propagation, diffraction, interference, and thin films. Under a broader interpretation, wave optics includes those areas of optics governed by the electromagnetic wave equation. We begin with a brief review of the wave equation, which is built on the foundation of Maxwell's equations. Next is a translation of the wave equation into the propagation relations of linear systems theory. An interesting and useful aspect of propagation is the existence of helical light; light that twists as it travels. Another aspect of optical waves is its propagation from curved surfaces. We move on to interference and then diffraction. The hologram serves as an important example of interference, while the computer‐generated hologram is an example of control over diffraction. Talbot, or Fourier self‐imaging, is a stunning example of the richness of propagation from diffractive optical elements. Finally, we discuss the subject of phase retrieval from irradiance distributions on multiple surfaces.
Mass‐transfer coefficients in washcoated monoliths
Authors: Bhattacharya Madhuchhanda , Harold Michael P. , Balakotaiah Vemuri
Published: October 2004

The asymptotic mass‐transfer coefficients are determined in washcoated monoliths of various geometric shapes by solving the convection–diffusion equation in the fluid phase coupled with the diffusion–reaction equation in the washcoat. The dependency of the asymptotic Sherwood number (Sh∞) on washcoat properties (relative effective washcoat thickness λ, ratio of diffusivity of reactant in the fluid phase to that in the washcoat δ, and the catalyst loading ϕ) is examined. It is found that in the kinetic regime (ϕ → 0), Sh∞ approaches a new asymptote (Shw,∞) which depends on the flow as well as washcoat geometries. For δ → 0, Shw,∞ approaches Sh corresponding to flow geometry, whereas for δ → ∞ it approaches Sh of flow geometry. As can be expected, in the mass transfer controlled regime, Sh∞ approaches ShT,∞ (flow geometry), which is independent of washcoat properties. It is also found that the variation of Sh∞ with catalyst loading is not always monotonic when washcoat distribution around the channel perimeter is nonuniform. Numerical results, describing the variation of Sh∞ with washcoat properties, are presented for some commonly used channel geometries. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2939–2955, 2004
Simulation and optimal design of multiple‐bed pressure swing adsorption systems
Authors: Jiang Ling , Fox V. Grant , Biegler Lorenz T.
Published: October 2004

Pressure swing adsorption (PSA) is a very versatile technology for gas separation and purification. The widespread industrial application of PSA has called for an efficient set of simulation, design, and optimization methodologies. In previous work by Jiang and co‐workers, we used a Newton‐based approach to quickly converge the cyclic steady state and design constraints, and a simultaneous tailored approach with the state‐of‐art nonlinear optimization strategy to design optimal PSA processes. In this work we extend the simulation and optimization strategies to multiple bed systems. Both unibed and multibed frameworks are adopted to describe bed behaviors. The unibed framework models only one bed over a cycle and uses storage buffers to mimic the bed interactions. The multibed framework simultaneously solves all beds but only for a portion of the cycle. Challenges and implementation details of both frameworks are discussed. A five‐bed, 11‐step hydrocarbon separation process, which separates H2 from a mixture of H2, N2, CO2, CO, and CH4, is used for illustration. By manipulating valve constants, step times, flow rates, and bed geometry, the optimizer successfully maximizes H2 recovery, while meeting product purity and pressure specifications. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2904–2917, 2004
Time‐integrated pointers for enabling the analysis of detailed reaction mechanisms
Authors: Androulakis Ioannis P. , Grenda Jeffrey M. , Bozzelli Joseph W.
Published: October 2004

A procedure for deriving time‐integrated pointers to capture element transformations during numerical integration runs, on complex chemical mechanisms, is introduced. The principal advantage is that the resulting temporally integrated pointers allow derivation of importance criteria; and these weight the contribution of all species and reactions during the reaction interval. This approach quantifies the sources and sinks of reactions active over a period of time in terms of element flux. It provides identification of key reaction pathways and the derivation of a reduced skeletal representation at minimum computational cost, in the elementary mechanism analysis. We extend the analysis to more complex systems, such as burner‐stabilized flames, that are governed by both reaction and diffusion. Here, we illustrate how some reaction pathways are altered in the presence of diffusion. Finally a new coupling of mechanism generation and mechanism reduction, which significantly reduces the computational burden associated with automated kinetic mechanism generation, is presented. The concepts are demonstrated with examples involving high‐ and low‐temperature oxidation of hydrocarbons. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2956–2970, 2004
Monoliths as multiphase reactors: A review
Authors: Roy Shaibal , Bauer Tobias , Al‐Dahhan Muthanna , Lehner Peter , Turek Thomas
Published: October 2004

Monolith reactors are being studied as a replacement for conventional multiphase reactors such as trickle‐bed reactors, slurry reactors, and slurry bubble column reactors for gas–liquid–solid reactions. Reactors with monolith catalyst packing have been found to be hydrodynamically superior to existing industrial reactors. This review covers multiphase reactions carried out in monolith reactors by various researchers. It first defines the monolith reactor and looks into the geometrical aspects of monolith. The section dealing with hydrodynamics reviews pressure drop, phase holdup, flow distribution, and dispersion characteristics. This study also considers the tools used to characterize the hydrodynamic parameters and their typical values. Although the available literature is scarce, monoliths are considered to have superior mass transfer characteristics. This review lists the mass transfer correlations for each category (gas–liquid, gas–solid, liquid–solid). The last section discusses the reaction aspects of monolith reactors. The ultimate goal is to implement such reactors for multiphase reactions. This section also compares the performance of monolith reactors with conventional multiphase reactors and lists the various reactor models reported to predict the overall performance of monolith reactors. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2918–2938, 2004
Phenotypic manifestations of the OCTN2 V295X mutation: Sudden infant death and carnitine‐responsive cardiomyopathy in Roma families
Authors: Melegh Béla , Bene Judit , Mogyorósy Gábor , Havasi Viktória , Komlósi Katalin , Pajor László , Oláh Éva , Kispál Gyula , Sumegi Balázs , Méhes Károly
Published: October 2004

In two non‐consanguineous Hungarian Roma (Gypsy) children who presented with cardiomyopathy and decreased plasma carnitine levels, we identified homozygous deletion of 17081C of the SLC22A5 gene that results in a frameshift at R282D and leads ultimately to a premature stop codon (V295X) in the OCTN2 carnitine transporter. Carnitine treatment resulted in dramatic improvement of the cardiac symptoms, echocardiographic, and EKG findings in both cases. Family investigations revealed four sudden deaths, two of them corresponded to the classic SIDS phenotype. In postmortem tissue specimens available from three of them we could verify the homozygous mutation. In liver tissue reserved from two patients lipid droplet vacuolization could be observed; the lipid vacuoles were located mainly in the peripherolobular regions of the acini. In the heart tissue signs of generalized hypertrophy and lipid vacuoles were seen predominantly in the subendocardial areas in both cases; some aggregates of smaller lipid vacuoles were separated, apparently by membranes. Review of all OCTN2 deficiency cases reported so far revealed that this is the first presentation of histopathology in classic familial sudden infant death syndrome (SIDS) with an established SLC22A5 mutation. In addition to the two affected homozygous cardiomyopathic children and three homozygous sudden death patients, the genetic analysis in 25 relatives showed 14 carriers. The mutant gene derived from five non‐consanguineous grandparents, each of them having 6–14 brothers and sisters. This alone suggests a wide ancestral spread of the mutation in certain Roma subpopulations. © 2004 Wiley‐Liss, Inc.
Anforderungen an Umkehrdächer mit Trennlage: Erläuterungen zur Anwendung von EN ISO 6946
Authors: Leimer Hans‐Peter , Bednar Thomas , Dreyer Jürgen , Künzel Hartwig M. , Palier Pierre , Rode Carsten , Tejchmann‐Konarzewski Jacek
Published: October 2004

Dieser Beitrag soll für unterschiedliche Regionen in Europa die Anwendung der Norm EN ISO 6946 im Hinblick auf Wärmeverluste beim Umkehrdach erläutern. In der Fassung dieser Norm von Oktober 2003 wird bei der Bestimmung des Wärmedurchgangskoeffizienten bei Umkehrdächern ein zusätzlicher, niederschlagsbedingter Wärmeverlust berücksichtigt. Die zusätzlichen Wärmeverluste eines Daches, die bedingt durch den Abfluß von erwärmten Niederschlägen unterhalb der Wärmedämmung entstehen, können somit rechnerisch erfaßt werden. Die Größe der Wärmeverluste ist abhängig von der Niederschlagsmenge und dem Anteil der Wassermenge, die direkt zwischen Dachabdichtung und Wärmedämmung abläuft. Diese Veröffentlichung soll die Anwendung der Norm für unterschiedliche Regionen in Europa erläutern. Hierzu werden ergänzend Klimadaten und Randbedingungen verschiedener Regionen dargestellt. Zudem werden bei Umkehrdächern mit Trennlage die Anforderungen an die Trennlage beschrieben. Hierbei werden die niederschlagsbedingten Wärmeverluste in der Folge soweit verringert, daß diese rechnerisch unberücksichtigt bleiben können.
Vorgehensweise zur gesundheitlichen Bewertung von VOC‐ und SVOC‐Emissionen aus Bauprodukten: Bewertungskonzept des Ausschusses zur gesundheitlichen Bewertung von Bauprodukten (AgBB)
Authors: Witten Jutta
Published: October 2004

Innenraumrelevante Bauprodukte können als bedeutsame Emissionsquellen von flüchtigen organischen Stoffen auftreten und dabei in erheblichen Maß die Qualität der Raumluft beeinflussen. Öffentlich rechtliche Anforderungen an Bauprodukte zum Gesundheitsschutz der Raumnutzer sind in der europäischen Bauproduktenrichtlinie (89/106/EWG) und durch Umsetzung in nationales Recht im Bauproduktengesetz bzw. den Landesbauordnungen verankert. Mit der europäischen Bauprodukten‐Richtlinie werden die notwendige Anforderungen an die Bereiche “Gesundheit, Hygiene und Umwelt” definiert, die im Grundlagendokument 3 der europäischen Kommission ausgeführt sind. Hierzu gehören besonders die Anforderungen Schadstoffemissionen aus Bauprodukten sowie Vermeidung und Begrenzung von flüchtigen organischen Verbindungen (VOC) in Innenräumen. Da für die Umsetzung dieser gesundheitsbezogenen Anforderungen eine offiziell anerkannte Vorgehensweise bisher nicht vorliegt, hat der Bund‐/Länderausschuss zur gesundheitlichen Bewertung von Bauprodukten (AgBB) Prüfkriterien zur gesundheitlichen Beurteilung von flüchtigen organischen Verbindungen (VOC‐ und SVOC‐Emissionen) aus Bauprodukten konkretisiert und veröffentlicht. Diese am Baurecht angelehnte Verfahrensweise stellt mit dem Ziel der Beschränkung von Emissionen von flüchtigen organischen Verbindungen aus Bauprodukten standardisierte Prüfnachweise sowie gesundheitlich relevante Bewertungsgrundlagen zur Verfügung. Vor dem Hintergrund bauaufsichtlicher Erfordernisse ermöglicht diese objektivierbare und besonders transparente Vorgehensweise zukünftig Verbrauchern, Architekten, Planern und auch Bauproduktherstellern innenraumrelevante Bauprodukte bereits im Vorfeld nach ihrer Schadstoff‐ und Emissionsrelevanz zu erkennen und zielgerecht einzusetzen.
Modellierung des Single Burning Item Tests
Authors: Hofmann Anja
Published: October 2004

Im Rahmen der Vereinheitlichung der Normen in Europa wurde der Single Burning Item (SBI) Test als neuer europäischer Brandtest für Bauprodukte für das mittlere Beanspruchungsniveau entwickelt. In diesem Test wird ein Entstehungsbrand in einer Zimmerecke nachgestellt, der durch einen einzelnen brennenden Gegenstand, z.B. durch einen brennenden Papierkorb, ausgelöst wird. Der SBI‐Test wurde von der Bundesanstalt für Materialforschung und ‐prüfung (BAM) und der TU Berlin mit numerischen Modellen untersucht und diese anhand von Experimenten validiert. Es zeigt sich ein signifikanter Einfluß der Belüftung des Brandraums und der Umgebungstemperatur auf die Temperatur‐ und Strömungsverhältnisse im Brandraum. In DIN EN 13823 sind jedoch für beide Parameter nicht feste Werte, sondern Bereiche angegeben. Neue Experimente, in der die einzelnen Parameter Belüftung, Umgebungstemperatur und möglicherweise auch Luftfeuchte der Umgebungsluft gezielt variiert werden, wären zur weiteren Klärung notwendig. Die vorhandenen Daten und die numerischen Ergebnisse geben Anlaß zu der Frage, ob die Bereiche, in denen die Belüftung und die Umgebungstemperatur variiert werden dürfen, in der Norm zu weit gefaßt sind.
High‐Temperature Synthesis of Stable Ordered Mesoporous Silica Materials by Using Fluorocarbon–Hydrocarbon Surfactant Mixtures
Authors: Li Defeng , Han Yu , Song Jiangwei , Zhao Lan , Xu Xianzhu , Di Yan , Xiao Feng‐Shou
Published: October 2004

Highly ordered hexagonal mesoporous silica materials (JLU‐20) with uniform pore sizes have been successfully synthesized at high temperature (150–220 °C) by using fluorocarbon–hydrocarbon surfactant mixtures. The fluorocarbon–hydrocarbon surfactant mixtures combine the advantages of both stable fluorocarbon surfactants and ordered hydrocarbon surfactants, giving ordered and stable mixed micelles at high temperature (150–220 °C). Mesoporous JLU‐20 shows extraordinary stability towards hydrothermal treatment (100 % steam at 800 °C for 2 h or boiling water for 80 h), thermal treatment (calcination at 1000 °C for 4 h), and toward mechanical treatment (compressed at 740 MPa). Transmission electron microscopy images of JLU‐20 show well‐ordered hexagonal arrays of mesopores with one‐dimensional (1D) channels and further confirm that JLU‐20 has a two‐dimensional (2D) hexagonal (P6 mm) mesostructure. 29Si HR MAS NMR spectra of as‐synthesized JLU‐20 shows that JLU‐20 is primarily made up of fully condensed Q4 silica units (δ=−112 ppm) with a small contribution from incompletely cross‐linked Q3 (δ=−102 ppm) as deduced from the very high Q4/Q3 ratio of 6.5, indicating that the mesoporous walls of JLU‐20 are fully condensed. Such unique structural features should be directly attributed to the high‐temperature synthesis, which is responsible for the observed high thermal, hydrothermal, and mechanical stability of the mesoporous silica materials with well‐ordered hexagonal symmetry. Furthermore, the concept of “high‐temperature synthesis” is successfully extended to the preparation of three‐dimensional (3D) cubic mesoporous silica materials by the assistance of a fluorocarbon surfactant as a co‐template. The obtained material, designated JLU‐21, has a well‐ordered cubic Im3m mesostructure with fully condensed pore walls and shows unusually high hydrothermal stability, as compared with conventional cubic mesoporous silica materials such as SBA‐16.
Structure and Dynamics of Homoleptic Beryllocenes: A Solid‐State 9Be and 13C NMR Study
Authors: Hung Ivan , Macdonald Charles L. B. , Schurko Robert W.
Published: October 2004

The correlation between anisotropic 9Be NMR (quadrupolar and chemical shielding) interactions and the structure and dynamics in [Cp2Be], [${{\rm Cp}{{\ast \hfill \atop 2\hfill}}}$Be], and [(C5Me4H)2Be] is examined by solid‐state 9Be NMR spectroscopy, as well as by ab initio and hybrid density functional theory calculations. The 9Be quadrupole coupling constants in the three compounds correspond well to the relative degrees of spherical ground‐state electronic symmetry of the environment about beryllium. Theoretical computations of NMR interaction tensors are in excellent agreement with experimental values and aid in understanding the origins of NMR interaction tensors and their correlation to molecular symmetry. Variable‐temperature (VT) 9Be and 13C NMR experiments reveal a highly fluxional structure in the condensed phase of [Cp2Be]. In particular, the pathway by which the Cp rings of [Cp2Be] ‘invert’ coordination modes is examined in detail using hybrid density functional theory in order to inspect variations of the 9Be NMR interaction tensors. The activation energy for the ‘inversion’ process is found to be 36.9 kJ mol−1 from chemical exchange analysis of 13C VT CP/MAS NMR spectra. The low‐temperature (ca. −100 °C) X‐ray crystal structures of all three compounds have been collected and refined, and are in agreement with previously reported structures. In addition, the structure of the same Cp2Be crystal was determined at 20 °C and displays features consistent with increased intramolecular motion, supporting observations by 9Be VT NMR spectroscopy.
New Types of Soluble Polymer‐Supported Bisphosphine Ligands with a Cyclobutane Backbone for Pd‐Catalyzed Enantioselective Allylic Substitution Reactions
Authors: Zhao Dongbo , Sun Jie , Ding Kuiling
Published: October 2004

A highly efficient and practical optical resolution of anti head‐to‐head racemic coumarin dimer 7 has been achieved by molecular complexation with TADDOL, (−)‐8, through a hydrogen bonding interaction to afford the corresponding two enantiomers, (−)‐ and (+)‐7, in 70 and 75 % yields, respectively, with >99 % ee. Starting from enantiopure (−)‐7, a new type of C2‐symmetric bisphosphine ligand (S,S,S,S)‐3 with a cyclobutane backbone has been synthesized in good yield by facile transformations. The asymmetric induction efficiency of these chiral bisphosphine ligands in Pd‐catalyzed asymmetric allylic substitution reactions was evaluated. Under the experimental conditions, the allylic substitution products could be obtained in excellent yields (up to 99 %) and enantioselectivities (up to 98.9 % ee). By taking advantage of the high enantioselectivity of this catalytic reaction and the easily derivable carboxylate groups on the cyclobutane backbone of ligand (S,S,S,S)‐3, a new type of analogous ligand (S,S,S,S)‐4 as well as the MeO‐PEG‐supported soluble ligand (S,S,S,S)‐5 (PEG=polyethylene glycol) have also been synthesized and utilized in asymmetric allylic substitution reactions. In particular, the MeO‐PEG supported (S,S,S,S)‐5 b had a synergistic effect on the enantioselectivity of the reaction compared with its nonsupported precursor (S,S,S,S)‐4 c, affording the corresponding allylation products 14 a and 14 b with excellent enantioselectivities (94.6 and 97.2 % ee, respectively). Moreover, the Pd complex of (S,S,S,S)‐5 b could easily be recovered and recycled several times without significant loss of enantioselectivity and activity in the allylic substitution reactions.
By What Mechanisms Are Metal Cyclobutadiene Complexes Formed from Alkynes?
Authors: Veiros Luís F. , Dazinger Georg , Kirchner Karl , Calhorda Maria José , Schmid Roland
Published: October 2004

The mechanism of formation of an η4‐cyclobutadiene complex from a metallacycle, generated by oxidative coupling of two acetylenes with the fragments CpRuCl, [CpRu(PH3)]+, CpCo, and CpRh, was investigated by means of DFT/B3LYP calculations. Two distinct pathways can be envisaged. 1) A multistep reaction, which can be denoted the Vollhardt mechanism, proceeding via a cyclopropenyl carbene and a tetrahedrane‐type intermediate. 2) A one‐step transformation involving the formation of a third MC bond with rearrangement of the metallacyclic ring. Although path 2 is definitely favored over path 1, both pathways are energetically prohibitive unless substituents are present on the acetylene. For the CpRuCl system with HCCR the barrier varies with R in the series H≈Ph>Me≫SiMe3. On going from H to SiMe3, the barrier for path 2 drops from 41.1 to 26.8 kcal mol−1. This latter value is already reachable, in agreement with experiment. Whereas the reaction mechanisms involving the fragments CpCo, CpRh, and CpRuCl are very similar (but not identical owing to the additional ligand in CpRuCl), those of [CpRu(PH3)]+ reveal a modification with serious consequences. In both paths 1 and 2, the originally planar metallacycle experiences first a bending distortion induced by the σ‐donor strength of P (in contrast to Cl), which compensates the loss of electrons from the ring brought about by bending. The bent metallacycle is already electronically asymmetric and thus the further course of the reaction is facilitated.
Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H2O)4 in [Zn(OAc)2(μ‐bpe)]⋅2 H2O: X‐ray and Neutron Diffraction Studies
Authors: Ng Meng Tack , Deivaraj Theivanayagam C. , Klooster Wim T. , McIntyre Garry J. , Vittal Jagadese J.
Published: October 2004

The reaction of 4,4′‐bipyridylethane (bpe) and 4,4′‐dipyridyl disulfide (dpds) with Zn(OAc)2⋅2 H2O has led to the formation of two coordination polymers, [Zn(OAc)2(μ‐bpe)]⋅2 H2O (1) and [Zn(OAc)2(μ‐dpds)] (2). Both the compounds have zigzag coordination polymeric structures as revealed by X‐ray crystallography. However, the presence of two lattice water molecules in 1 results in an interesting difference between the crystal structures. In 1, the carboxylate carbonyl oxygen atoms of the Zn(OAc)2 groups from two different adjacent zigzag polymers and four lattice water molecules form 24‐membered hydrogen‐bonded rings (graph set notation, R66(24)). One of the two bpe ligands associated with each ZnII center passes through the center of this ring to form a two‐dimensional hydrogen‐bonded coordination polymeric structure. In the solid state, the adjacent 24‐membered hydrogen‐bonded rings further fuse together through OH⋅⋅⋅O hydrogen bonds among four waters to form cyclic (H2O)4. This results in a one‐dimensional hydrogen‐bonded ribbon‐like polymer comprising fused alternating 24‐ and eight‐membered OH⋅⋅⋅O hydrogen‐bonded rings. One of the bpe ligands passes through the center of the larger ring to produce an unexpected single self‐penetrating three‐dimensional hydrogen‐bonded network with polyrotaxane‐like association. A neutron diffraction study provides a detailed description of the hydrogen bonds involved.
Illuminating Zinc in Biological Systems
Authors: Lim Nathaniel C. , Freake Hedley C. , Brückner Christian
Published: October 2004

Zinc is the second most abundant transition metal in the human body, fulfilling a multitude of biological roles, but the mechanisms underlying its physiology are poorly understood. The lack of knowledge is, in part, due to the hitherto limited techniques available to track zinc in biological systems. The recent emergence of a number of zinc‐specific molecular sensors has provided a new tool to image zinc in live cells and tissue samples. This contribution highlights the concepts behind using zinc‐specific fluorescent molecular sensors to gain information about zinc action in biological samples, and provides representative examples of images recorded.
A New Class of Non‐Racemic Chiral Macrocycles: A Conformational and Synthetic Study
Authors: Gibson Susan E. , Mainolfi Nello , Kalindjian S. Barret , Wright Paul T. , White Andrew J. P.
Published: October 2004

Amino alcohols have been used to introduce non‐racemic chirality into macrocycles using a modular approach that relies on a Heck macrocyclisation reaction. A wide variety of macrocycles have been synthesised, and their structures studied using X‐ray crystallography and molecular modelling. A fragmentation reaction encountered during the use of (S)‐1,1‐dimethylvalinol revealed that carboxylic acids generate acylals under reaction conditions often used for Heck reactions.