bluuebunny/crossref_metadata_2025 huggingface dataset:
The environmental accident at ‘Schweizerhalle’ and respiratory diseases in children: A time series analysis
Authors: Helfenstein Ulrich , Ackermann‐Liebrich Ursula , Braun‐Fahrländer Charlotte , Wanner Hans Urs
Published: April 2007

During an investigation concerned with the relationship between air pollution and respiratory diseases in children, the ‘Schweizerhalle’ accident occurred when unknown amounts of pollutants were discharged into the environment. In that investigation, two series of medical data were collected during one year: (a) The daily relative number of preschool children, exhibiting diseases of the respiratory tract, who either came to the outpatients' clinic of the Children's Hospital or were reported by paediatricians in Basle; (b) The daily number of respiratory symptoms per child, observed in a group of randomly selected preschool children. The purpose of the present time series analysis is the assessment of possible change in these series after the environmental accident. The nature of the change is studied by complementary approaches. First, a forecast arising from models identified in the preaccident period is compared with the actual data. Thereafter, intervention models which adequately and parsimoniously represent the change are identified. Finally, an identification of a change‐point is performed.
A time series construction of an alert threshold with application to S. Bovismorbificans in France
Authors: Watier Laurence , Richardson Sylvia , Hubert Bruno
Published: April 2007

Epidemiological surveillance can be used to initiate preventive measures and Salmonella infection is a prime example of application. It is important that any unusual increase of reported cases should be detected as rapidly as possible. Reliable forecasts based on a suitable model of the temporal structure of a pathological indicator are necessary for the elaboration of an alert threshold. We first discuss the specific problems associated with the identification and the estimation of the temporal structure of indicators of infectious diseases when they present both epidemic peaks and an underlying stationary structure. Then we consider how an alert threshold can be defined. Our application concerns infections caused by S. bovismorbificans in France for which an alert threshold is constructed and tested both retrospectively and prospectively.
On the estimation of total variability in assay validation
Authors: Chow Shein‐Chung , Tse Siu‐Keung
Published: April 2007

In the pharmaceutical industry, an assay method is considered validated if the accuracy and precision for an assay meet some acceptable limits. This paper discusses the assessment of assay precision in terms of the estimation of total variability of an assay from a one‐way random effects model which is often considered in assay validation. We propose a general class of estimators that includes the analysis of variance estimator and the maximum likelihood estimator. We derive the optimal estimator, in terms of smallest mean squared error, within this class and consider an approximate version of this optimal estimator. We report on a Monte Carlo simulation to study its finite sample performance. We also present two examples to illustrate the use of the proposed methodology.
Interpretation of interaction in factorial analysis of variance design
Authors: Ottenbacher Kenneth J.
Published: April 2007

The validity of statistical conclusions in medical research depends on proper analysis and interpretation of collected data. One potential area of invalidity is the inappropriate post hoc analysis of statistically significant interactions in the analysis of variance of factorial designs. This paper examines the statistical explanations included in 83 studies published in three leading medical journals where the findings indicated significant interaction effects. Only 24 per cent of the reported statistically significant interactions had an accompanying correct interpretation. The most common form of misinterpretation involved a comparison of individual cell means within a row or column of one factor used in the design. This interpretation did not conform to the factorial ANOVA model with interaction. This misinterpretation occurs when the correct omnibus test of a hypothesis is followed by an incorrect post hoc analysis and/or an inaccurate assessment of the original statistical result.
Analysis of clinical trials by treatment actually received: Is it really an option?
Authors: Lee Young Jack , Ellenberg Jonas H. , Hirtz Deborah G. , Nelson Karin B.
Published: April 2007

The primary analysis of a randomized clinical trial should compare patients in their randomly assigned treatment groups (intention to treat analysis). When a substantial number of subjects fail to take a prescribed medication or are switched to a different study medication, it is tempting to consider treatment comparisons using only those subjects with treatment as actually received rather than as prescribed. There are several arguments against this approach: the prognostic balance brought about by randomization is likely to be disturbed; sample size will be reduced; and the validity of the statistical test procedures will be undermined. Further, results of analysis by treatment actually received may suffer from a bias introduced by using compliance, a factor often related to outcome independently of the treatment received, to determine the groups for comparison. The extent and nature of this bias will be related to the definition of compliance in an as treated analysis, a definition which could be unintentionally self‐serving.

We have investigated the problem of the definition of actual treatment in the context of a recent clinical trial. We used several definitions to classify patients as having received or not received treatment as prescribed. These definitions, when used in as treated analyses, provided results that were at times inconsistent or counter‐intuitive, and which neither helped to confirm nor further explain the intention to treat analysis.
The analysis of categorical data from cross‐over trials using a latent variable model
Authors: Kenward Michael G. , Jones Byron
Published: April 2007

A latent variable model for categorical data is described. The nuisance parameters in the model can be eliminated from the analysis through the use of a conditional likelihood and this leads to an analysis based on a log‐linear model. It is shown how the structure of a cross‐over trial allows considerable simplification in the formulation of this model and routine application of well‐known statistical packages. The method is illustrated by data from a three‐period cross‐over trial on the relief of primary dysmenorrhea using the GLIM and SAS packages.
The healthy responder phenomenon in non‐randomized clinical trials
Authors: Hallstrom Alfred P. , Greene H. Leon , Huther Melissa L. ,   AND THE CAST INVESTIGATORS
Published: April 2007

An example from the Cardiac Arrhythmia Suppression Trial (CAST) illustrates what we term the ‘healthy responder’ phenomenon. The hypothesis is that patients who respond to a given treatment are healthier than patients who do not respond. In observational studies this results in an apparent but not real benefit for the treatment. The unique design of CAST, namely, titration before randomization, allows illustration of this phenomenon since we can view the study as both a non‐randomized as well as a randomized trial of therapy. We conclude that, in demonstration of a drug effect, randomized trials are essential.
Analysis of failure time data with ordinal categories of response
Authors: Berridge Damon M. , Whitehead John
Published: April 2007

When failure times are observed, additional information concerning the type of failure is often recorded. A method which simultaneously models the failure times and additional information in the form of ordinal categories is discussed. An application to clinical trial data, in which the failure times are times of onset of headache, and the headaches are classified into the ordinal categories mild, moderate and severe, illustrates how this method may be used and how the final model can be interpreted. The continuation ratio model, which is used in this method, is described in detail.
The detection of artefacts in eeg series
Authors: Dunstan F. D. J. , Marshall R. W.
Published: April 2007

In a clinical trial of an anticonvulsant drug, series of electroencephalogram readings are sometimes obtained. These may contain artefacts, that is patches of atypical values which must be identified and either removed or compensated for before a full analysis can be carried out. Methods for identifying such artefacts are discussed. These include non‐parametric methods and also parametric ones combining the ideas of autoregressive modelling and of influence in regression. These methods are described and illustrated on typical data sets.
Subacute sclerosing panencephalitis in England and Wales: Transient effects and risk estimates
Authors: Farrington C. P.
Published: April 2007

Data on cases of subacute sclerosing panencephalitis (SSPE) with onset in 1970‐89 show a marked increase in the interval from initial measles attack to onset of SSPE by year of onset. It is shown that this increase is a transient effect resulting from the decline in measles incidence following the introduction of mass vaccination in 1968. The risk of SSPE after measles is estimated to be 4.0 × 10−5 (18 × 10−5 after measles under one year of age) and the risk after vaccination to be no greater than 0.14 × 10−5, thus confirming that vaccination is effective in reducing the incidence of SSPE. The paper makes use of methods developed to estimate the incubation period of AIDS.
Estimation of relative risk functions
Authors: Bithell J. F.
Published: April 2007

The risk associated with different levels of a quantitative factor X is often measured relative to the level corresponding to X = 0. There are situations, however, where there is no natural zero for X, for example where the risk factor is the age of an individual. In this case it is more natural to measure risk relative to an overall average for the study population. To use the whole population in this way also raises the possibility of regarding X as truly continuous, rather than as a grouped variable. This gives rise to the concept of a relative risk function. Methods for estimating such functions are discussed, concentrating for the most part on the discrete case. The extension to higher dimensions permits the investigation of joint effects of several factors, while the problem of controlling for confounding variables can be handled by fitting multiplicative risk models. Relating the latter to the log‐linear model permits the estimation of adjusted relative risk functions. The method is illustrated using data on childhood cancer. The continuous case can in principle be handled in a similar way using density estimation techniques.
A decade of progress in statistical methodology for clinical trials
Authors: Simon Richard
Published: April 2007

Clinical trials played a dominant and expanding role in the evaluation of new treatments during the decade of the 1980s. There were major improvements in the quality of clinical trials in many medical fields. There were also important developments in the methodology of designing, monitoring, conducting, analysing, reporting and interpreting clinical trials. This paper attempts to review some of these developments. A comprehensive review is beyond the abilities of any one individual. Consequently, this paper attempts to offer a broad stroke description of this area and to highlight specific topics of importance based on my particular experience. An extensive, but non‐comprehensive bibliography is included to provide entry points to the literature of methodologic developments for clinical trials in the 1980s.
Survival analysis 1982–1991: The second decade of the proportional hazards regression model
Authors: Andersen Per Kraghersen
Published: April 2007

A short review of the Cox regression model and its development from publication to 1982 is given. I discuss how the model is used and presented in medical journals and how improvement may be achieved. Finally, some extensions of the model are outlined.
Sampling design of multiwave studies with an application to the Massachusetts health care panel study
Authors: Chappell Rick
Published: April 2007

A technique is presented which provides guidance on the spacing of follow‐up waves in a multiwave study. Only information from the baseline wave is needed, as well as rough parameter estimates for the survival distribution. The computations use the expected Fisher information; a new method for its calculation is given. An analysis of the effects of simplifying assumptions, such as presuming that a distributional parameter is known, shows that gross discrepancies may result. Data from the Massachusetts Health Care Panel Study (MHCPS) are used for a demonstration. The MHCPS example shows that this technique can prevent large inefficiencies in multiwave experimental design.
Semi‐parametric and non‐parametric methods for the analysis of repeated measurements with applications to clinical trials
Authors: Davis Charles S.
Published: April 2007

Techniques applicable for the analysis of longitudinal data when the response variable is non‐normal are not nearly as comprehensive as for normally‐distributed outcomes. However, there have been several recent developments. Semi‐parametric and non‐parametric methodology for the analysis of repeated measurements is reviewed. The commonly encountered design in which, for each subject, one assesses a univariate response variable at multiple fixed time points, is considered. The types of outcomes considered include binary, ordered categorical, and continuous (but extremely non‐normal) response variables. All of the methods considered allow for incomplete data due to the occurrence of missing observations. In addition, discrete and/or continuous covariates, which may be time‐dependent, are accommodated by some of the approaches. The methods are demonstrated using data from three clinical trials.
Application of the McNemar test to non‐independent matched pair data
Authors: Eliasziw Michael , Donner Allan
Published: April 2007

McNemar's one degree of freedom chi‐square test for the equality of proportions appears frequently in the analysis of pairs of matched, binary outcome data (Y1i, Y2i). An assumption underlying this test is that the responses from pair to pair are mutually independent. In certain applications, however, the pairs may represent repeated measurements on the same experimental unit, and hence this assumption is violated. In this paper we suggest an adjustment to the McNemar test to account for the repeated measures clustering effect and we report on a Monte Carlo simulation that evaluates the effectiveness of this approach.
Smoothing reference centile curves: The lms method and penalized likelihood
Authors: Cole T. J. , Green P. J.
Published: April 2007

Reference centile curves show the distribution of a measurement as it changes according to some covariate, often age. The LMS method summarizes the changing distribution by three curves representing the median, coefficient of variation and skewness, the latter expressed as a Box‐Cox power. Using penalized likelihood the three curves can be fitted as cubic splines by non‐linear regression, and the extent of smoothing required can be expressed in terms of smoothing parameters or equivalent degrees of freedom. The method is illustrated with data on triceps skinfold in Gambian girls and women, and body weight in U.S.A. girls.
Optimal checking procedures for monitoring laboratory analyses
Authors: McShane Lisa M. , Turnbull Bruce W.
Published: April 2007

Many clinical, environmental, and epidemiologic studies rely heavily upon biochemical data, and the quality of these data is of paramount importance to the validity of study conclusions. Traditionally, far more attention has been given to the analysis of study data than has been given to monitoring the quality of the data. In this paper we draw an analogy between monitoring a laboratory system and an industrial production process and discuss the limitations of industrial quality control plans when applied in a laboratory setting. We derive methods for computing optimal checking schedules for laboratory analyses. These schedules formalize traditional laboratory practices of periodic checking and provide guidelines for the frequency and placement of checks within a finite batch of analyses. When laboratory system failure can be reasonably approximated by an exponential or geometric distribution, optimal checking schedules are relatively easy to compute. For more complex failure distributions, we present a dynamic programming approach. We describe an application to the measurement of selenium status in plasma samples using an electrothermal atomic absorption spectrophotometry procedure.
Sample size determination for group sequential clinical trials with immediate response
Authors: Kim Kyungmann , Demets David L.
Published: April 2007

The use function approach to group sequential methods has been explored previously. Any group sequential design requires specifying the frequency and times of repeated analyses, but only the use function approach allows deviations from those specified in the design, without affecting the type I error in the analysis. This paper illustrates how the use function provides a simple and flexible design procedure and how the initially projected maximum sample size can be calculated for randomized clinical trials in which responses are known relatively soon after patient entry and for which there is an early stopping rule built into the study protocol. Also the consequence of using the proposed design procedure is investigated in terms of the operating characteristics of the subsequent group sequential analyses.
Study duration for group sequential clinical trials with censored survival data adjusting for stratification
Authors: Kim Kyungmann
Published: April 2007

The study duration in a clinical trial with censored survival data is the sum of the accrual duration, which determines the sample size in a traditional sense, and the follow‐up duration, which more or less controls the number of events to be observed. We propose a design procedure for determining the study duration or for calculating the power in a group sequential clinical trial with censored survival data and possibly unequal patient allocation between treatments, adjusting for stratified randomization. The group sequential method is based on the use function approach. We describe a clinical trial recently activated by the Eastern Cooperative Oncology Group for an illustration of the proposed procedure.
A goodness‐of‐fit approach to inference procedures for the kappa statistic: Confidence interval construction, significance‐testing and sample size estimation
Authors: Donner Allan , Eliasziw Michael
Published: April 2007

We propose a new procedure for constructing a confidence interval about the kappa statistic in the case of two raters and a dichotomous outcome. The procedure is based on a chi‐square goodness‐of‐fit test as applied to a model frequently used for clustered binary data. The procedure provides coverage levels that are accurate in samples of smaller size than those required for other procedures. The procedure also has use for significance‐testing and the planning of corresponding sample size requirements.
Analysis of aberrations in public health surveillance data: Estimating variances on correlated samples
Authors: Kafadar Karen , Stroup Donna F.
Published: April 2007

The detection of unusual patterns in health data presents an important challenge to health workers interested in early identification of epidemics or important risk factors. A useful procedure for detection of aberrations is the ratio of a current report to some historic baseline. This work addresses the problem of finding the variance of such a ratio when the surveillance reports are correlated. Results show that, when estimating this variance or the variance of the sample mean from a series of observations with an estimated correlation structure, bootstrap and jackknife estimates may be overly optimistic. The delta method or a classical method may be more useful when such model dependence is inappropriate.
The epidemic dynamics of HIV‐1 in Italy: Modelling the interaction between intravenous drug users and heterosexual population
Authors: Arcà Massimo , Perucci Carlo A. , Spadea Teresa
Published: April 2007

Data gathered through the Latium HIV Surveillance System were used in conjunction with a compartmental mathematical model to describe the transmission dynamics of HIV‐1 in Italy. In the Latium region, as in the rest of Italy, fewer than 1 in 5 cumulative cases of AIDS are attributable to male homosexual transmission, while 55–60 per cent of the cases have been observed among intravenous drug users (IVDUs). Moreover, the number of non‐drug‐using heterosexual cases is increasing (14 per cent of cumulative cases). Anonymous notification of positive HIV‐1 tests, mandatory in Latium since 1985, were used to produce a time series of new HIV‐1 diagnoses; just over 400 new cases of infection per quarter were diagnosed from mid 1989 to mid 1990, with no evidence of increasing incidence. A minimum of 6009 and a maximum of 10,000 individuals with HIV‐1 as of the end of 1989 were estimated, 80 per cent of adult cases occurring among IVDUs. The model included two main subgroups: IVDUs and non‐drug‐using heterosexuals, both with behavioural heterogeneities. Sharing of needles among IVDUs and heterosexual contact were considered as possible ways of transmitting HIV‐1. A mathematical framework was developed to reproduce different mixing patterns within and between subgroups. A scenario analysis of the model showed incident cases of HIV‐1 among IVDUs peaking early, then declining dramatically and stabilising at low values, with a stable‐state prevalence higher than 0.75. Heterosexual interaction with IVDUs resulted in a significant, but non‐self‐sustaining, virus spread in the general population, affecting females more than males. The extent of this spread is associated with the assortativeness of the sexual mixing pattern adopted. The qualitative features of the Italian epidemic are well represented by the model, which highlights the role of IVDUs as an infection reservoir. However, the need emerges for more accurate information on the key parameters influencing the transmission dynamics of HIV‐1.
Repeated measures in clinical trials: Analysis using mean summary statistics and its implications for design
Authors: Frison Lars , Pocock Stuart J.
Published: April 2007

This paper explores the use of simple summary statistics for analysing repeated measurements in randomized clinical trials with two treatments. Quite often the data for each patient may be effectively summarized by a pre‐treatment mean and a post‐treatment mean. Analysis of covariance is the method of choice and its superiority over analysis of post‐treatment means or analysis of mean changes is quantified, as regards both reduced variance and avoidance of bias, using a simple model for the covariance structure between time points. Quantitative consideration is also given to practical issues in the design of repeated measures studies: the merits of having more than one pre‐treatment measurement are demonstrated, and methods for determining sample sizes in repeated measures designs are provided. Several examples from clinical trials are presented, and broad practical recommendations are made. The examples support the value of the compound symmetry assumption as a realistic simplification in quantitative planning of repeated measures trials. The analysis using summary statistics makes no such assumption. However, allowance in design for alternative non‐equal correlation structures can and should be made when necessary.
Prediction of short‐term survival with an application in primary biliary cirrhosis
Authors: Hughes Michael D. , Raskino Claire L. , Pocock Stuart J. , Biagini Maria Rosa , Burroughs Andrew K.
Published: April 2007

Many long‐term follow‐up studies for survival accumulate repeated measurements of prognostic factors. Survival models which include only covariate values at baseline do not use all available information, and do not relate to survival predictions for times other than at that baseline. Time‐dependent covariate models (which update covariate values as measurements occur through time) might be used, though limitations of software for estimating the underlying hazard functions and difficulty in relating hazard function changes to survival prediction present serious drawbacks. By dividing each patient's follow‐up into successive intervals of equal length (using a length of interest for prediction) and with measurements available at the start of each, we describe how an analysis taking person‐intervals as the observation units can be undertaken using readily available software to produce short‐term survival models. We show that this approach is related to both the baseline and time‐dependent covariate models. The method is illustrated using data from a long‐term study of patients with primary biliary cirrhosis, where interest is in short‐term survival predictions to aid the decision when to undertake liver transplantation.
Importance of good nonlinear analysis
Authors: Krawinkler Helmut
Published: April 2007

Nonlinear analysis is becoming a popular tool for performance evaluation of structural systems at the life safety and collapse prevention levels. The challenge is to develop analytical tools and component models that make it possible to conduct such analysis with a sufficient degree of confidence. An exact replication of reality is desirable but not critical because of many sources of uncertainty, such as ground motion intensity and frequency content, and modeling uncertainties, which cannot be eliminated by the most accurate analysis. As summarized in this paper, there are several options to nonlinear analysis, and the simplest one that gets close to reality is usually the best one. Observation of behavior during the analysis (whether pushover or time history) is perhaps more important than a rigorous quantitative evaluation based on maximum recorded force or deformation values. In the author's opinion, the main objective of nonlinear analysis is to understand behavior rather than fulfill code‐specified limit values. This paper presents arguments why this is a critical issue, even though it is understood that reality in engineering practice usually dictates priority to fulfilling code specified limits. Copyright © 2006 John Wiley & Sons, Ltd.
LATBSDC alternative design case study—concrete shear wall only beyond 240‐foot LABC code limit: optimized behavior
Authors: Youssef Nabih , Wilkerson Ryan , Fischer Kurt
Published: April 2007

The resurgence of high‐rise construction has presented a challenge for the structural engineering community to bridge the gap between the requirements of prescriptive building code procedures and optimal structural system design. In response, the Los Angeles Tall Building Structural Design Council has formulated an alternate design procedure that provides a tool for the engineer to use to optimize the design the lateral force resisting system for high‐rise buildings with the goal of achieving a design that would yield a performance at least equivalent to the prescriptive methods contained within the building code. Using the alternate procedures, a case study was performed for a sample high‐rise building and compared to the same building design by prescriptive code procedures. The comparison was aimed at determining whether it could be concluded that an equivalent performance was obtained and what the required structural elements are for the two approaches. Lastly, a discussion of the benefits and drawbacks alternative design process itself is presented. Copyright © 2006 John Wiley & Sons, Ltd.
RF MEMS technology
Authors: Kim Hyeon Cheol , Chun Kukjin
Published: April 2007

Recently, to meet the demands of multimode/multiband functions for the next generation communication systems, RF MEMS technology is being developed for the reconfigurable transceiver system. In this article, RF MEMS devices such as switches, high‐Q inductors, and high‐Q resonators are reviewed for their operating principles and device structures, as well as the reliability and commercial issues. Single pole single throw (SPST)‐type MEMS switches show characteristics superior to solid‐state switches in the aspects of insertion loss, isolation, and linearity. Single pole multithrow (SPMT) switches will enable ultra small‐sized cellular phones, but insertion loss and coupling between channels should be improved. For a high‐Q inductor, out‐of‐plane inductors show improved results, and an inductor with a Q‐factor of 75 at 1GHz has been fabricated by using the internal stress of a MoCr film. The MEMS inductor improves the performance of a voltage controlled oscillator (VCO), but proper hermetic packaging and standard libraries are also necessary for mass production. The MEMS resonator can operate up to 1.4 GHz and can be used as an oscillator for the timing device as well as component of the filter circuit. The SiTime Company recently has started delivery of a product with performance similar to the quartz oscillator, in which they solved the reliability issues by modifying the annealing and vacuum packaging. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Fast calculation method for fine‐tuned design of need‐based collateralized debt obligation (CDO)
Authors: Nakae Tatsuya , Baba Kenji , Moritsu Toshiyuki , Komoda Norihisa
Published: April 2007

In this paper we propose a speed‐up method for need‐based collateralized debt obligation (CDO) that meets the investor needs of the attributes of the CDO. We note the fact that the computing time to derive the best portfolio is proportional to the number of generated contract conditions that constitute the portfolio. Our method reduces the number of portfolios that can never be the best portfolios by skipping the generation of redundant contract conditions of Super Senior (SS) debt and Equity debt, which is the main cause for the increase of the generated contract conditions. A comparative experiment indicates that the proposed method makes it possible to double the types of tranches or to raise the calculation accuracy nearly 6‐fold, keeping the urgency of the calculation. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Low cross talk design and simple fabrication process of electrostatic vertical comb‐drive actuators for positioning application
Authors: Zickar Michael , Mita Makoto , Ataka Manabu , Fujita Hiroyuki
Published: April 2007

In this paper, different types of vertical electrostatic comb‐drive actuators are proposed. The aim of design is to minimize the cross talk between vertical and lateral motions with a relatively simple fabrication process, namely, with only two ICP‐RIE steps from the front side with layered masks. Three designs are analyzed by MEMCAD, a finite‐element modeling package, combined with a micromachining process simulator. After optimization based on the calculation, all types were fabricated and tested. The experimental results are qualitatively in good agreement with the calculations. Because of the excess undercutting in our ICP‐RIE machine, the supports were softer than designed. The displacement was larger than expected. According to obtained results, we can expect to generate a vertical force of 0.5 µN per tooth at around 50 V. The measured cross talk between vertical motion and the horizontal motion was 20%. The resonant frequency of a typical device is 9 kHz and the displacement is 1.5 µm at 50 V. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
High‐sensitivity surface micromachinable accelerometer using a ferroelectric substrate and its characterization
Authors: Aoyagi Seiji , Isono Yuichi
Published: April 2007

The present study reports the fabrication and characterization of a high‐sensitivity surface micromachinable accelerometer using a ferroelectric material having a large dielectric constant, such as bulk PZT (εr= 2600). The measurement principle is the detection of capacitance change with respect to the dielectric mass movement in the fringe electrical field. Considering the practical fabrication, a ferroelectric material is used for the substrate instead of the suspended proof mass. Since capacitance is increased not mechanically but electrically, high sensitivity can be expected while maintaining mechanical stiffness, which has the advantage of preventing touch down of the proof mass and widening the allowable measuring range of acceleration. A fabricated sensor is characterized. A high sensitivity of several sub‐pF/g is confirmed, which is hundreds of times higher compared to that of a sensor fabricated using the Parylene polymer (εr= 3.15). This sensitivity is an order higher compared to those of other reported capacitive microaccelerometers, which have comparable proof mass sizes and comparable detectable acceleration ranges to the newly fabricated sensor. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Novel fabrication method for long silicon microneedles with three‐dimensional sharp tips and complicated shank shapes by isotropic dry etching
Authors: Izumi Hayato , Aoyagi Seiji
Published: April 2007

This paper proposes a novel fabrication method for long solid microneedles made of silicon, which have a three‐dimensional sharp tip, by using isotropic dry etching. Since the fabrication is done in a direction parallel to the surface of the silicon substrate, there is no limit for the needle length. Also, the shank shape of this needle is freely designed three‐dimensionally by defining the mask on the silicon surface. For example, a jagged or harpoon shape is possible by using the proposed method, which may be effective for some medical applications. First, several three‐dimensional, complicated‐shaped needles with sharp tip angles were fabricated by changing the mask pattern. Second, a penetration experiment with them on an artificial skin was carried out, and easy penetration comparable with a conventional metal solid needle was confirmed. For an example of lancet application for diabetics, one of the needles was inserted into a human skin, and bleeding was confirmed. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Cellular automaton simulation of micropowder blasting with mask erosion
Authors: Yagyu Hiromasa , Tabata Osamu
Published: April 2007

Development of a two‐dimensional (2D) micropowder blasting simulator for microfabrication of a glass substrate with a patterned polymer mask is reported. In order to investigate the effect of mask erosion on a processed glass profile, a cellular automaton simulation in which erosion of the glass and the polymer mask were taken into account was applied to the micropowder blasting process for the first time. From a comparison of the simulation result with the processed glass profile in the experiment, it was demonstrated that the processed glass profile with the mask erosion could be simulated using our simulator. Furthermore, it was confirmed that the processed profile in the glass depended on the mask profile and the ratio of the deformation wear and the cutting wear of a mask. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Syntheses and Crystal Structures of Hydrated Ternary Cerium Sulfates: Mixed‐valence K5Ce2(SO4)6·H2O and K2Ce(SO4)3·H2O
Authors: Casari Barbara M. , Langer Vratislav
Published: April 2007

A new chemical and structural interpretation of K5Ce2(SO4)6·H2O (I) and a redetermination of the structure of K2Ce(SO4)3·H2O (II) is presented. The mixed‐valent compound I crystallizes in the space group C2/c with a = 17.7321(3), b = 7.0599(1), c = 19.4628(4) Å, β = 112.373(1)° and Z = 4. Compound I has been discussed earlier with space group Cc. In the structure of I, there are pairs of edge sharing cerium polyhedra connected by sulfate oxygen atoms in the μ3 bonding mode. These cerium dimers are linked through edge and corner sharing sulfate bridges, forming layers. The layers are joined by potassium ions which together with the water molecules are placed between the layers. No irregularity in the distribution of the CeIII and CeIV to cause the lost of a crystallographic center of symmetry was detected. We suggest that the charge exerted by the extra f1 electron for every cerium dimer is delocalized over the Ce1–O2–Ce2 moiety in a non‐bonding mode. As a result, the oxidations state of each cerium ion is a mean value between III and IV at each atomic position. Compound II crystallizes in the space group C2 with a = 20.6149(2), b = 7.0742(1), c = 17.8570(1) Å, β = 122.720(1)° and Z = 8. The hydrogen atoms have been located and the absolute structure has been established. Neither hydrogen atom positions nor anisotropic displacement parameters were given in the previous reports. In compound II, the cerium polyhedra are connected by edge and corner sharing sulfate groups forming a three‐dimensional network. This network contains Z‐shaped channels hosting the charge compensating potassium ions.
Synthesis and Spectroscopic Characterization of New Lead(II) Thiosaccharinates. Molecular Structure of Bis(thiosaccharinato)tetrakis(pyridine)dilead(II) and Thiosaccharinato‐bis(1,10‐phenantroline)lead(II) Thiosaccharinate
Authors: Pérez Diego R. , Tarulli Susana H. , Quinzani Oscar V. , Dristas Jorge , Faccio Ricardo , Suescun Leopoldo , Mombrú Alvaro W.
Published: April 2007

Four new lead(II) thiosaccharinate complexes: [Pb(tsac)2H2O] (1) (tsac: thiosaccharinate anion), [Pb2(tsac)4(py)4] (2) (py: pyridine), [Pb(tsac)(o‐phen)2](tsac)·CH3CN (3) (o‐phen: 1,10‐phenantroline), and [Pb(tsac)2(bipy)] (4) (bipy: 2,2′‐bipyridine) were prepared. The infrared and electronic spectra as well as the thermal analysis of all the compounds were recorded and discussed. The thiosaccharinate anion acts in three different coordination forms, one of then reported for the first time. The crystal structures of complexes 2 and 3 have been determined by single crystal X‐ray diffractometry. In complex 2, two monomeric moieties are joined together forming a symmetric bis‐μ‐sulphur bridged dimer by interaction of two lead(II) atoms through the exocyclic sulphur atoms of two thiosaccharinate ligands. The seven‐fold coordination sphere of each lead atom is completed by two pyridine nitrogen atoms and by another sulfur and two nitrogen atoms of the thiosaccharinate anions. In complex 3, the lead(II) atom is coordinated by four nitrogen atoms of two 1,10‐phenantroline molecules and by the sulfur and nitrogen atoms of one thiosaccharinate ion. The second anion has an electrostatic interaction with the nucleus.
Über den Phosphandiyl‐Transfer von invers‐polarisierten Phosphaalkenen R1P=C(NMe2)2 (R1 = tBu, Cy, Ph, H) auf Phospheniumkomplexe [(η5‐C5H5)(CO)2M=P(R2)R3] (R2 = R3 = Ph; R2 = tBu, R3 = H; R2 = Ph, R3 = N(SiMe3)2)
Authors: Weber L. , Noveski G. , Stammler H.‐G. , Neumann B.
Published: April 2007

Phosphanediyl Transfer from Inversely Polarized Phosphaalkenes R1P=C(NMe2)2 (R1 = tBu, Cy, Ph, H) onto Phosphenium Complexes [(η5‐C5H5)(CO)2M=P(R2)R3] (R2 = R3 = Ph; R2 = tBu, R3 = H; R2 = Ph, R3 = N(SiMe3)2)

Reaction of the freshly prepared phosphenium tungsten complex [(η5‐C5H5)(CO)2W=PPh2] (3) with the inversely polarized phosphaalkenes RP=C(NMe2)2 (1) (a: R = tBu; b: Cy; c: Ph) led to the η2‐diphosphanyl complexes $\rm [(\eta^{5}-C_{5}H_{5})(CO)_{2}\overline {W-P(R)-P}Ph_{2}]$ (9a‐c) which were isolated by column chromatography as yellow crystals in 24‐30 % yield. Similarly, phosphenium complexes [(η5‐C5H5)(CO)2M=P(H)tBu] (M = W (6); Mo (8)) were converted into $\rm [(\eta^{5}-C_{5}H_{5})(CO)_{2}\overline {MP({\it t}Bu)P}(H){\it t}Bu]$ (M = W (11); Mo (12)) by the formal abstraction of the phosphanediyl [PtBu] from 1a. Treatment of [(η5‐C5H5)(CO)2W=P(Ph)N(SiMe3)2] (4) with HP=C(NMe2)2 (1d) gave rise to the formation of yellow crystalline $\rm [(\eta^{5}-C_{5}H_{5})(CO)_{2}\overline {W-P(H)-P} (Ph)N(SiMe_{3})_{2}]$ (10). The products were characterized by elemental analyses and spectra (IR, 1H, 13C‐, 31P‐NMR, MS). The molecular structure of compound 10 was elucidated by an X‐ray diffraction analysis.
The Structure of Tris(trifluoromethyl)tellurium Fluoride Dimethylformamide, $\rm [Te(CF_{3})_{3} \times DMF(\mu-F)]{\infty}$
Authors: Kirij Natalya V. , Yagupolskii Yurii L. , Tyrra Wieland , Pantenburg Ingo , Naumann Dieter
Published: April 2007

$\rm [Te(CF_{3})_{3} \times DMF(\mu-F)]{\infty}$ represents the first structurally characterized example of a trifluoromethyl main group element compound with more than 8‐N (where N is the main group number) perfluoroalkyl groups and also the first fluoro(triorgano)tellurium derivative. Its polymeric nature is caused by asymmetric bridging fluorine atoms forming infinite chains.
Vitamin B13 Complexes of Nickel(II) and Copper(II) with Ethanolamine: Syntheses, Crystal Structures, Spectroscopic and Thermal Studies
Authors: Yeşsilel Okan Zafer , Şahin Ertan
Published: April 2007

Fac‐bis(ethanolamine)orotatonickel(II), [Ni(HOr)(ea)2] and mer‐bis(ethanolamine)orotatocopper(II) dihydrate, [Cu(HOr)(ea)2]· 2H2O were synthesized and characterized by elemental analysis, FT‐IR, UV‐Vis Spectroscopy and thermal analysis. In addition, their solid‐state structures were determined by single crystal X‐ray diffraction studies. Both the fac‐[Ni(HOr)(ea)2] (1) and mer‐[Cu(HOr)(ea)2]·2H2O (2) complexes are isomorphous and crystallize in the triclinic space group $P {\bar 1}$. The Ni2+ and Cu2+ ions are coordinated by two neutral ea ligands and one orotate dianion in a distorted octahedral fashion. The ea ligand acts as a bidentate donor through the amine N and hydroxyl O atoms, while orotate dianion is coordinated through deprotonated N3 pyrimidine atom and carboxylate oxygen atom as a bidentate ligand. Thermal decompositions of the complexes are studied in over the range 20–600 °C on heating in a static air atmosphere.
Structural and Spectroscopic Studies of Halocuprate(I) and Haloargentate(I) Complexes [M2XnX′4−n]2−
Authors: Bowmaker Graham A. , Bruce Michael I. , Skelton Brian W. , Somers Neil , White Allan H.
Published: April 2007

The complexes [Cu2Br4]2−, [Cu2I4]2−, [Cu2I2Br2]2−, [Cu2I3Cl]2−, [Ag2Cl4]2− have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph3PNPPh3]+ = PNP+) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)2MX]2− with three‐coordinate metal atoms that have been observed in [M2X4]2− complexes with other large organic cations. In [Cu2I2Br2]2− the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu2I3Cl]2−, obtained in an attempt to prepare [Cu2I2Cl2]2−, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag2Cl4]2− the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag2Cl4]2− complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu2X4]2− complexes.
Isolation and identification oftrans‐3,5‐dimethoxystilbene from high quality tall oil fatty acids by liquid chromatography and mass spectrometry
Authors: Min David B. S. , Chang Stephen S.
Published: April 2007

trans‐3,5‐Dimethoxystilbene has been isolated from high quality tall oil fatty acids (unsaponifiables 1.5% maximum, rosin acids 1.5% maximum), using liquid column chromatography and low temperature solvent fractional crystallization. The structure of this compound was determined with the aid of IR, mass and NMR spectrometry. Thetrans‐3,5‐dimethyoxystilbene was found to be responsible for the development of a red color during the epoxidation of the tall oil fatty acids.
Some practical aspects connected with the presence of calcium in soybean oils
Authors: Letan A. , Yaron A.
Published: April 2007

Presence of calcium in crude and degummed soybean oils prevents complete elimination of phosphatides by hydration and enhances the formation of heavy precipitates. They block industrial centrifuges at the later stages of the refining processes. Industrially extracted degummed soybean oils contain appreciable amounts of calcium (ca. 100 ppm) and its source was traced to the processed soybeans. Various pre‐extraction treatments of the soybeans in industry augment the calcium content in the oils, since crude Soxhlet‐extracted soybean oils contained only 15 ppm calcium. Additions at the alkali‐refining stages of EDTA or of polyphosphate, to stabilize aqueous suspensions which also contain calcium salts, are suggested as a partial remedy to the frequent blocking of the centrifuges.
Projection and prospects for rapeseed and mustard seed
Authors: Ohlson Ragnar
Published: April 2007

Rapeseed is number five among the oilseeds of the world. During the last 10 years the crop has increased more in per cent than any other oilseed crop. In the FAO prospects an annual rate of increase of 4.7% is foreseen. The fatty acid composition will change during the next years so that erucic acid will be practically removed. The content of glucosinolates will also be reduced dramatically, and consequently the meal will be accepted much more readily.
Crystallization of hydrogenated sunflower‐cottonseed oil
Authors: Rivarola G. , Segura J. A. , Añón M. C. , Calvelo A.
Published: April 2007

Crystal structures formed during solidification of hydrogenated cottonseed oil, sunflowerseed oil and their blends were analyzed by using an X‐ray diffraction technique, differential scanning calorimetry (DSC) and polarized light microscopy. Temperatures and times of crystallization under conditions which tend to produce β′ type structures were determined in terms of refrigeration parameters. Microscopy with polarized light also helped clarify some aspects of the tridimensional network of crystals that contribute to the consistency of products made from hydrogenated oils.
Reaction of methyltrans‐2,3‐epoxyoctadecanoate with phenyl isocyanate: Synthesis of fatty 3‐phenyl‐2‐oxazolidones
Authors: Ansari M. H. , Ahmad M.
Published: April 2007

Reaction of methyltrans‐2,3‐epoxyoctadecanoate (I) with phenyl isocyanate in dimethylformamide (DMF) in the presence of anhydrous AlCl3 as catalyst has yielded 3‐phenyl‐4‐pentadecylmethyleneoxazolid‐2,5‐dione (II) and 4(5)‐carbomethoxy‐5 (4)‐pentadecyl‐3‐phenyl‐cis‐2‐oxazolidone (III). The products have been characterized with the help of spectral data and microanalyses.
Preparation and characterization of double‐chain destructible surfactants and derived vesicles
Authors: Jaeger David A. , Golich Timothy G.
Published: April 2007

Double‐chain destructible surfactants 1 and 2 were prepared, and vesicles derived from them were characterized. The hydrolyses of 1 and 2 to nonsurfactant compounds were demonstrated, and the application of 1 and 2 in preparative chemistry and in pH‐controlled delivery is discussed.
Reductive ozonolysis of soybean oil: Laboratory optimization of process variables
Authors: Throckmorton P. E. , Pryde E. H.
Published: April 2007

Statistically designed experiments were carried out to determine the effect of reaction variables in the reductive ozonolysis of soybean oil to azelaaldehydic glyceride methyl acetal. Yields of this acetal were essentially quantitiative under optimum conditions, which include a 1:1 mixture of acetic acid and butanol as solvent, a solvent‐oil ratio of 1.5:1, and hydrogenation at 150 psig and 50 C with palladiumon‐charcoal catalyst.