bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct roles of protein kinase R and toll‐like receptor 3 in the activation of astrocytes by viral stimuli
Authors: Carpentier Pamela A. , Williams Bryan R. , Miller Stephen D.
Published: November 2006

Impaired immune surveillance and constitutive immunosuppressive properties make the central nervous system (CNS) a particular challenge to immune defense, and require that CNS‐resident cells be capable of rapidly recognizing and responding to infection. We have previously shown that astrocytes respond to treatment with a TLR3 ligand, poly I:C, with the upregulation of innate immune functions. In the current study, we examine the activation of innate immune functions of astrocytes by Theiler's murine encephalomyelitis virus (TMEV), a picornavirus, which establishes a persistent infection in the CNS of susceptible strains of mice and leads to the development of an autoimmune demyelinating disease that resembles human multiple sclerosis. Astrocytes infected with TMEV are activated to produce type I interferons, the cytokine IL‐6, and chemokines CCL2 and CXCL10. We further examined the mechanisms that are responsible for the activation of astrocytes in response to direct viral infection and treatment with poly I:C. We found that the cytoplasmic dsRNA‐activated kinase PKR is important for innate immune responses to TMEV infection, but has no role in their induction by poly I:C delivered extracellularly. In contrast, we found that TLR3 has only a minor role in responses to TMEV infection, but is important for responses to poly I:C. These results highlight the differences between responses induced by direct, nonlytic virus infection and extracellular poly I:C. The activation of astrocytes through these different pathways has implications for the initiation and progression of viral encephalitis and demyelinating diseases such as multiple sclerosis. © 2006 Wiley‐Liss, Inc.
PKCϵ induces astrocytic differentiation of multipotential neural precursor cells
Authors: Steinhart Rivka , Kazimirsky Gila , Okhrimenko Hana , Ben‐Hur Tamir , Brodie Chaya
Published: November 2006

In this study, we examined the role of PKC in the differentiation of multipotential neural precursor cells (NPCs). We found that the NPCs expressed PKCα,β2,δ,ϵ,ζ and low levels of PKCγ. The PKC activator, PMA, selectively increased the number of astrocytes, whereas it decreased the generation of neurons and oligodendrocytes. Similarly, overexpression of PKCϵ increased the differentiation of astrocytes and a PKCϵKD mutant abolished PMA effect. PMA phosphorylates PKCϵ on serine 729. Using a PKCϵS729A mutant, we found that the phosphorylation of PKCϵ on serine 729 was essential for the differentiation of astrocytes induced by PMA. To delineate the mechanisms involved in PMA and PKCϵ effects, we examined the expression of Notch1, which has been associated with astrocytic differentiation. We found that PMA and PKCϵ induced a large increase in Notch1 expression and the PKCϵS729A mutant abolished PMA effect. Moreover, the PKCϵS729A mutant also inhibited the effect of CNTF on astrocytic differentiation and Notch 1 expression. Finally, Notch1 mediated the effect of PMA on astrocytic differentiation, since the γ‐secretase inhibitor L‐685,458, and Notch1 silencing abolished PMA effect. Our data suggest an important role of PKCϵ in astrocytic differentiation and implicate Notch1 as a possible mediator of this effect. © 2006 Wiley‐Liss, Inc.
Neogene aquifer properties specified through the interpretation of electrical sounding data, Salamiyeh region, central Syria
Authors: Asfahani Jamal
Published: November 2006

Twenty‐nine Schlumberger electrical soundings were carried out in the Salamiyeh region in Syria using a maximum current electrode separation of 1 km. Three soundings were made at existing boreholes for comparison. Aquifer parameters of hydraulic conductivity and transmissivity were obtained by analysing pumping test data from the existing boreholes. An empirical relationship between hydraulic conductivity determined from the pumping test and both resistivity and thickness of the Neogene aquifer has been established for these boreholes in order to calculate the geophysical hydraulic conductivity. A close agreement has been obtained between the computed hydraulic conductivity and that determined from the pumping test. The relationship established has, therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the hydraulic conductivity and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers. Copyright © 2006 John Wiley & Sons, Ltd.
Investigations on surface and subsurface drainage requirements at regional scale
Authors: Kumar Krishan , Singh J. , Gupta S. K.
Published: November 2006

Amongst the three drainage basins in Haryana (India), the inland drainage basin is most prone to surface stagnation, rise in groundwater table and soil salinization. In order to understand the surface and subsurface drainage requirements of this basin, a number of groundwater regime maps (groundwater table contour map, depth to groundwater table map, groundwater fluctuation map and groundwater quality map) were prepared to assess long‐term groundwater table behaviour in a part (comprising Rohtak and Jhajjar districts) of this basin for the period 1984–98. Groundwater movement was observed to occur towards the central part of the study area, a possible cause of waterlogging and degradation in groundwater quality. The groundwater levels during the past two and a half decades (1974–98) registered a rise varying from 1 to 19 m with an average rise of 21 cm yr−1. The rainfall data of Rohtak and Jhajjar districts for the period (1975–98) were analysed for different frequencies of exceedance to determine 1, 2 and 3 days of consecutive rainfall. The surface drainable surplus was calculated taking into account the water storage in the soil profile, infiltration rates and evaporation that varied from 30–35, 35–40 and 5 mm day−1 respectively. The drainable surplus for consecutive 1, 2 and 3 days' rainfall for a 5‐year return period was 161, 113 and 0 m3 s−1 respectively. The existing surface drainage system with a capacity of 170 m3 s−1 and with availability of dead storage, could handle 1 and 2 days' consecutive rainfall for a 5‐year return period when full initial storage of 30–35 cm (equivalent to 50% of the available moisture) is available in the soil profile. From the groundwater regime maps, it was also estimated that nearly 16% of the study area (57 932 ha) required treatment with subsurface drainage. Therefore, a groundwater model (SWAP) was used to predict the subsurface drainable surplus considering various inputs related to the water balance of the area. The subsurface drainable surplus over the simulated years ranged between 0.4 and 1.92 mm day−1. This range is quite close to the recommended range of the subsurface drainage coefficient for this region on the basis of field trials. The study of irrigation and drainage maps of the area revealed that there is a need to strengthen field surface drains and introduce subsurface drainage in the area. As such, the methodology proposed in this paper could be used to investigate drainage requirements on a regional scale. Copyright © 2006 John Wiley & Sons, Ltd.
The welfare effects of restricted hospital choice in the US medical care market
Authors: Ho Katherine
Published: November 2006

Managed care health insurers in the USA restrict their enrollees' choice of hospitals to within specific networks. This paper considers the implications of these restrictions. A three‐step econometric model is used to predict consumer preferences over health plans conditional on the hospitals they offer. The results indicate that consumers place a positive and significant weight on their expected utility from the hospital network when choosing plans. A welfare analysis, assuming fixed prices, implies that restricting consumers' choice of hospitals leads to a loss to society of approximately $1 billion per year across the 43 US markets considered. This figure may be outweighed by the price reductions generated by the restriction. Copyright © 2006 John Wiley & Sons, Ltd.
Frequent mutation of p16CDKN2A exon 1 during rat tongue carcinogenesis induced by 4‐nitroquinoline‐1‐oxide
Authors: Hong Yun , Yang Linglan , Li Chunyang , Xia Hongbin , Rhodus Nelson L. , Cheng Bin
Published: November 2006

In this study we explored the mutation types of p16CDKN2A exon 1 and the corresponding frequencies in experimental rat tongue carcinogenesis. Twenty barrier Sprague–Dawley (SD) rats were divided into the control (n = 5) and experimental group (n = 15), to which 4‐nitroquinoline‐1‐oxide (4‐NQO) in drinking water was administered. Two samples of normal, three samples of moderate/severe dysplasia and four samples of invasive squamous cell carcinoma lesions were selected following strict histopathological examination in double‐blind manner. The PCR products of p16CDKN2A exon 1 amplified from these tissues were sequenced. Point mutations of p16CDKN2A exon 1 were found in all of the precancerous and cancerous lesions. Half of the mutations were detected on guanine (G). Twenty mutations, including a missense mutation of the start codon resulting in alternative reading frame of p16CDKN2A exon 1, were also identified. These preliminary results suggested that mutation of p16CDKN2A exon 1 might be an early molecular event of rat tongue carcinogenesis induced by 4NQO and G was the mutation hotspot. © 2006 Wiley‐Liss, Inc.
Deoxycholic acid promotes the growth of colonic aberrant crypt foci
Authors: Flynn Christopher , Montrose David C. , Swank Daniel L. , Nakanishi Masako , Ilsley Jillian N.M. , Rosenberg Daniel W.
Published: November 2006

AKR/J mice are resistant to the tumorigenic properties of the colon carcinogen, azoxymethane (AOM). Following AOM exposure, limited numbers of preneoplastic lesions, referred to as aberrant crypt foci (ACF), are formed in the colon, and their progression to tumors rarely occurs. To determine whether genetic resistance can be overcome by exposure to a dietary tumor promoter, AOM‐exposed AKR/J mice were fed a diet containing 0.25% deoxycholic acid (DCA). DCA exposure was begun 1 wk prior to or 1 wk after tumor initiation with AOM. Mice placed on the DCA diet prior to AOM treatment developed a significantly higher multiplicity of ACF compared to AOM‐exposed mice fed a control diet (15.50 ± 0.96 vs. 6.17 ± 0.48, respectively; P < 0.05). When DCA exposure was begun after AOM treatment (post‐initiation), ACF formation was further enhanced (34.00 ± 1.22). Interestingly, increased numbers of ACF were associated with the presence of nuclear β‐catenin, assessed by immunohistochemistry. While ∼33% of ACF from mice exposed to DCA prior to AOM treatment contained positive nuclear β‐catenin staining, ∼77% of ACF from mice fed DCA after AOM were positive. Accumulation of nuclear β‐catenin was not associated with a loss of E‐cadherin from the plasma membrane, although loss of APC staining was a consistent feature of most AOM‐induced ACF, regardless of DCA exposure. These results demonstrate that exposure to DCA, an important digestive component, is sufficient to sensitize the resistant AKR/J colon to formation of high‐grade dysplasia, and that nuclear translocation of β‐catenin may play an important role in this process. © 2006 Wiley‐Liss, Inc.
Expression of secretory phospholipase A2 in colon tumor cells potentiates tumor growth
Authors: Belinsky Glenn S. , Rajan Thiruchandurai V. , Saria Elizabeth A. , Giardina Charles , Rosenberg Daniel W.
Published: November 2006

Secretory phospholipase A2 (sPLA2‐IIA) has been shown to attenuate intestinal tumorigenesis in ApcMin mice, demonstrating that it is a tumor modifier. To further explore the actions of sPLA2‐IIA in tumorigenesis, sPLA2‐IIA was overexpressed in two cell lines where it is normally absent, the murine colon tumor cell line AJ02nm0, and human colon carcinoma cell line HCT‐116. Two allelic variants of sPLA2‐IIA were tested in this study; sPLA2‐IIAAKR and sPLA2‐IIASWR, which are derived from AKR/J and SWR/J mice, respectively, and differ by a single amino acid at position 63 in the calcium‐ and receptor‐binding domain. There was no change in cell‐doubling time for either allele when compared to vector controls. Furthermore, sodium butyrate and arachidonic acid (AA)‐induced cell death were unchanged in control and transfected cells. Addition of the sPLA2 substrate, palmitoyl‐arachidonoyl‐phosphatidic acid (PAPA), to AJ02nm0 cells resulted in a modest (12%–24%), but significant (P < 0.01), inhibition of growth that was dependent on sPLA2‐IIA expression. However, when AJ02nm0 and HCT‐116 cells were injected subcutaneously (sc) into nude mice, Pla2g2a expression resulted in a 2.5‐fold increase in tumor size. In addition, sPLA2‐IIA expressing HCT‐116 tumors were found to be more infiltrative than controls. We conclude that the ability of sPLA2‐IIA to slow tumor cell growth is dependent upon the availability of substrate, and that in some instances sPLA2‐IIA may actually enhance tumor growth. Mechanisms that may account for differences between the tumor explant model versus the ApcMin model of intestinal cancer are discussed. © 2006 Wiley‐Liss, Inc.
Adrenocortical oncocytoma in a child
Authors: Gumy‐Pause Fabienne , Bongiovanni Massimo , Wildhaber Barbara , Jenkins Jesse J. , Chardot Christophe , Ozsahin Hulya
Published: November 2006

Adrenocortical oncocytoma is a rare epithelial tumor only described in adults. We report the case of a 12‐year‐old female who presented a left adrenal mass with abdominal pain, fatigue, acne vulgaris, and elevation of the androstenedione and total testosterone. She had an adrenalectomy. A diagnosis of adrenocortical oncocytoma was made after detailed histological, immunohistochemical, and ultrastructural studies. Pediatr Blood Cancer 2008;50:718–721. © 2006 Wiley‐Liss, Inc.
Body composition, muscle strength deficits and mobility limitations in adult survivors of childhood acute lymphoblastic leukemia
Authors: Ness Kirsten K. , Baker K. Scott , Dengel Donald R. , Youngren Nancy , Sibley Shalamar , Mertens Ann C. , Gurney James G.
Published: November 2006

Background

Chronicity of muscle weakness from cancer and its treatment may be problematic, particularly in those treated for cancer during childhood. We compared body composition, muscle strength, and mobility between 75 adult survivors of childhood acute lymphoblastic leukemia (ALL) and expected values based on population normative data.

Methods

Subjects were young adults treated for childhood ALL between 1970 and 1986, selected randomly from participants in an ongoing study of cancer survivors. DeXA scans were performed to evaluate body composition, and myometry used to measure strength. Mobility was evaluated with the Timed Up and Go (TUG) and 2‐min walk (TMW). One sample t‐tests compared ALL survivors to population norms.

Results

Males had 4.5% and females had 2.3% more body fat than expected (expected males 21.5%, females 36.0%). Males were 76.7 Newtons and females were 58.6 Newtons weaker in quadriceps strength than expected (expected males 569.87 N, females 464.67 N). Males walked 100.88 m and females walked 85.38 m less on the TMW (expected values: males 304.23 m, females 276.26 m), and took longer to complete the TUG (males 5.82 vs. 2.84 sec, females 5.88 vs. 3.00 sec) than expected. Treatment with cranial radiation and current growth hormone (GH) deficiency were associated with lower body weakness among females.

Conclusions

Young adult survivors of childhood ALL have strength and mobility deficits. Decreased strength may reduce ability to participate in physical activity, perpetuating fitness deficits in survivors of childhood ALL. Pediatr Blood Cancer 2007;49:975–981. © 2006 Wiley‐Liss, Inc.
Dynamics of end‐grafted polystyrene brushes in theta solvents
Authors: Michailidou V. N. , Loppinet B. , Vo D. C. , Prucker O. , Rühe J. , Fytas G.
Published: November 2006

The dynamics of the concentration fluctuations in end‐grafted polystyrene brushes in a theta solvent (cyclohexane) are probed by evanescent wave dynamic light scattering at different wavevectors q and temperatures. When the solvent quality changes from marginal to poor, the relaxation function C(q, t) exhibits strong effects as compared with the smooth variation of the brush density profile. From a single exponential above 50 °C, C(q, t) becomes a two‐step decay function. The fast decay is still assigned to the cooperative diffusion albeit slower than in the good solvent regime whereas the slow nonexponential and nondiffusive process might relate to microsegragated and/or chain dynamics in the present polydisperse brush. The relaxation function of the present three brushes with different grafting density reveals similarities and disparities between wet brushes and semidilute polymer solutions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3590–3597, 2006
Relation between the adhesion strength and interfacial width for symmetric polystyrene bilayers
Authors: Akabori Kei‐Ichi , Baba Daisuke , Koguchi Kazuhiro , Tanaka Keiji , Nagamura Toshihiko
Published: November 2006

Polystyrene (PS) bilayers were prepared and were adhered at a temperature between the surface and bulk glass‐transition temperatures for a given time. Then, the interfacial adhesion strength (GL) was examined with a conventional lap‐shear measurement. GL first increased with increasing adhesion time and then reached a constant value. This result implied that the segments moved across the interface, to a certain depth, even at a temperature below the bulk glass‐transition temperature. To confirm this, the interfacial evolution for the PS/deuterated PS bilayers was examined with dynamic secondary‐ion mass spectrometry. The GL value was linearly proportional to the thickness of the interfacial adhesion layer. Finally, we propose a strategy for regulating the adhesion strength based on the chain‐end chemistry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3598–3604, 2006
Kondo effect in a three‐terminal quantum ring
Authors: Leturcq R. , Schmid L. , Ensslin K. , Driscoll D. C. , Gossard A. C.
Published: November 2006

The Kondo effect has been widely studied in semiconductor quantum dots, in particular due to the ability to study the system out‐of‐equilibrium. However, the information obtained from a quantum dot connected to two leads is not complete, and a better understanding of this regime can be achieved by connecting the system to a third lead. We have performed transport measurements on a three‐terminal quantum ring in the Kondo regime. With two leads strongly coupled to the ring, we have used the third weakly coupled lead as a tunnel probe in order to measure the Kondo density of states, and to study the decoherence of the Kondo state at large bias voltage. We also show that the three leads can be strongly coupled and all show a Kondo correlation with the ring, which is the first step towards observing a two‐channel Kondo effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Control and measurement of electron spins in semiconductor quantum dots
Authors: Kouwenhoven L. P. , Elzerman J. M. , Hanson R. , Willems van Beveren L. H. , Vandersypen L. M. K.
Published: November 2006

We present an overview of experimental steps taken towards using the spin of a single electron trapped in a semiconductor quantum dot as a spin qubit [Loss and DiVincenzo, Phys. Rev. A 57, 120 (1998)]. Fabrication and characterization of a double quantum dot containing two coupled spins has been achieved, as well as initialization and single‐shot read‐out of the spin state. The relaxation time T 1 of single‐spin and two‐spin states was found to be on the order of a millisecond, dominated by spin–orbit interactions. The time‐averaged dephasing time T 2*, due to fluctuations in the ensemble of nuclear spins in the host semiconductor, was determined to be on the order of several tens of nanosceconds. Coherent manipulation of single‐spin states can be performed using a microfabricated wire located close to the quantum dot, while two‐spin interactions rely on controlling the tunnel barrier connecting the respective quantum dots [Petta et al., Science 309, 2180 (2005)]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Single‐photon‐emitting diodes: a review
Authors: Bennett A. J. , Atkinson P. , See P. , Ward M. B. , Stevenson R. M. , Yuan Z. L. , Unitt D. C. , Ellis D. J. P. , Cooper K. , Ritchie D. A. , Shields A. J.
Published: November 2006

Compact and reliable sources of non‐classical light could find many applications in emerging technologies such as quantum cryptography, quantum imaging and also in fundamental tests of quantum physics. Single self‐assembled quantum dots have been widely studied for this reason, but the vast majority of reported work has been limited to optically excited sources. Here we discuss the progress made so far, and prospects for, electrically driven single‐photon‐emitting diodes (SPEDs). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron spin and nuclear spin manipulation in semiconductor nanosystems
Authors: Hirayama Yoshiro , Yusa Go , Sasaki Satoshi
Published: November 2006

Manipulations of electron spin and nuclear spin have been studied in AlGaAs/GaAs semiconductor nanosystems. Non‐local manipulation of electron spins has been realized by using the correlation effect between localized and mobile electron spins in a quantum dot‐ quantum wire coupled system. Interaction between electron and nuclear spins was exploited to achieve a coherent control of nuclear spins in a semiconductor point contact device. Using this device, we have demonstrated a fully coherent manipulation of any two states among the four spin levels of Ga and As nuclei. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherent population trapping in a single‐hole‐charged quantum dot
Authors: Imamoglu A.
Published: November 2006

Coherent population trapping in a single hole charged quantum dot could provide a powerful spectroscopic tool for understanding and controlling spin decoherence mechanisms. Measurement of the width of the transparency window as a function of magnetic field, temperature and gate voltage could be used to reveal the contributions of phonons, co‐tunneling and hyperfine interactions to hole decoherence. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lifting of spin blockade by hyperfine interaction in vertically coupled double quantum dots
Authors: Tarucha S. , Kitamura Yosuke , Kodera Tetsuo , Ono Keiji
Published: November 2006

The ability of the hyperfine interaction to lift spin blockade was studied for vertically coupled double quantum dots in two different regimes of potential detuning between the two dots. The double dot has a triplet state, which is a sufficiently long‐lived excited state to block current flow by the Pauli effect. This blockade is lifted by a spin flip transition to the singlet state, generating a leakage current. The singlet‐triplet separation or exchange energy decreases with increasing detuning. For small detuning, the leakage current shows a step when the Zeeman energy equals the exchange energy thus turning on the flip‐flop interaction. The threshold magnetic field gradually increases with decreasing detuning. It increases more abruptly near the resonance of two singlet states reflecting the increased exchange energy. For large detuning, the leakage current is caused by singlet‐triplet mixing due to the fluctuating nuclear field, and it decreases when the Zeeman energy exceeds the fluctuating nuclear field energy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (b) 243/14
Authors: Bougeard Dominique , Finley Jonathan , Grayson Matthew , Tornow Marc
Published: November 2006

The present special issue entitled Frontiers in Semiconductor Nanoscience has been prepared to honor Gerhard Abstreiter on the occasion of his 60th birthday and pay tribute to his long career, during which he has consistently operated at the frontiers in semiconductor physics and nanoscience. The twin issues in pss(a) and pss(b) consist of more than forty contributions from leading scientists in four of the general fields of semiconductor and nanostructure physics in which Gerhard has been most active: (i) quantum transport, (ii) optical properties and coherent phenomena, (iii) nano‐biological systems and (iv) novel materials and nanostructures. As discussed by Günther Bauer in his laudatio, Gerhard has consistently made highly significant contributions to each and every one of these fields throughout his career, often leading to new advances that have had a major impact in the fields of semiconductor nanostructures and condensed matter physics.

In addition to providing a fitting tribute to Gerhard's long scientific career, we hope that this issue will stimulate imaginative exploitation of these emerging and rapidly developing fields. We are sure that all contributors, colleagues and collaborators join us in wishing Gerhard a very happy birthday and look forward to working on future problems in the science of semiconductors and their nanostructures. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of Weibull small samples using Monte Carlo simulations
Authors: Lam R. , Spelt J. K.
Published: November 2006

The evaluation of the functional reliability of different designs is a common task and times to failure can be compared using the likelihood ratio test. In the microelectronics industry, as in many others, the high cost of testing places severe restrictions on the sample size. Moreover, the products in these tests are often new and do not have previous reliability histories. These factors make the selection of the Type I and Type II errors in comparison tests very difficult. This paper presents the Monte Carlo simulation results of Type II errors for the likelihood ratio test of comparison as a function of the Type I error and the (small) sample size. Our conclusions are summarized as follows: (1) the common microelectronics industry standard sample size of 32 is often insufficient to reach satisfactory conclusions; (2) small sample tests should only be used for prescreening for significant differences; and (3) when only small samples are available, the Type I and the Type II errors must be selected carefully to prevent misleading conclusions. Copyright © 2006 John Wiley & Sons, Ltd.
Cost‐penalized estimation and prediction evaluation for split‐plot designs
Authors: Liang Li , Anderson‐Cook Christine M. , Robinson Timothy J.
Published: November 2006

Comparisons between different designs have traditionally focused on balancing the quality of estimation or prediction relative to the overall size of the design. For split‐plot designs with two levels of randomization, the total number of observations may not accurately summarize the true cost of the experiment, because different costs are likely associated with setting up the whole and subplot levels. In this paper, we present several flexible measures for design assessment based onD‐,G‐ andV‐optimality criteria that take into account potentially different cost structures for the split‐plot designs. The new measures are illustrated with two examples: a 23factorial experiment for first‐order models, where all possible designs are considered, and selective designs for a three‐factor second‐order model. Copyright © 2006 John Wiley & Sons, Ltd.
Measuring process capability based on Cpmk with gauge measurement errors
Authors: Hsu B. M. , Shu M. H. , Pearn W. L.
Published: November 2006

Due to their effectiveness and simplicity of use, the process capability indices $C_{p}$, $C_{pk}$, and $C_{pm}$ have been popularly accepted in the manufacturing industry as management tools for evaluating and improving process quality. Combining the merits of those indices, a more advanced index, $C_{pmk}$, is proposed that takes into account process variation, process centering, and the proximity to the target value, and has been shown to be a very useful index for manufacturing processes with two‐sided specification limits. Most research works related to $C_{pmk}$ assume no gauge measurement errors. However, such an assumption inadequately reflects real situations even when highly advanced measurement instruments are employed. Conclusions drawn regarding process capability are therefore unreliable and misleading. In this paper, we conduct a sensitivity investigation for the process capability index $C_{pmk}$ in the presence of gauge measurement errors. We consider the use of capability testing of $C_{pmk}$ as a method for obtaining lower confidence bounds and critical values for true process capability when gauge measurement errors are unavoidable. The results show that using the estimator with sample data contaminated by measurement errors severely underestimates the true capability, resulting in an imperceptibly smaller test power. To measure the true process capability, three methods for the adjusted confidence bounds are presented and their performances are compared using computer simulation. Copyright © 2006 John Wiley & Sons, Ltd.
Monitoring capability indices using an EWMA approach
Authors: Castagliola Philippe , Vännman Kerstin
Published: November 2006

When performing a capability analysis it is recommended to first check that the process is stable, for example, by using control charts. However, there are occasions when a process cannot be stabilized, but it is nevertheless capable. Then the classical control charts fail to efficiently monitor the process position and variability. In this paper we propose a new strategy to solve this problem, where capability indices are monitored in place of the classical sample statistics such as the mean, median, standard deviation, or range. The proposed procedure uses the $C_p(u,v)$ family of capability indices proposed by Vännman combined with a logarithmic transformation and an EWMA approach. One important property of the procedure presented here is that the control limits used for the monitoring of capability indices only depend on the capability level assumed for the process. The experimental results presented in this paper demonstrates how this new approach efficiently monitors capable processes by detecting changes in the capability level. Copyright © 2006 John Wiley & Sons, Ltd.
Partial confounding and projective properties of Plackett–Burman designs
Authors: Kulahci Murat , Bisgaard Søren
Published: November 2006

Screening experiments are typically used when attempting to identify a few active factors in a larger pool of potentially significant factors. In general, two‐level regular factorial designs are used, but Plackett–Burman (PB) designs provide a useful alternative. Although PB designs are run‐efficient, they confound the main effects with fractions of strings of two‐factor interactions, making the analysis difficult. However, recent discoveries regarding the projective properties of PB designs suggest that if only a few factors are active, the original design can be reduced to a full factorial, with additional trials frequently forming attractive patterns. In this paper, we show that there is a close relationship between the partial confounding in certain PB designs and their projective properties. With the aid of examples, we demonstrate how this relationship may help experimenters better appreciate the use of PB designs. Copyright © 2006 John Wiley & Sons, Ltd.
Reliability Analysis of a conveyor system using hybrid data
Authors: Gupta Suprakash , Bhattacharya Jayanta
Published: November 2006

The quantification of a fault tree is difficult without an exact probability value for all of the basic events of the tree. To overcome this difficulty in this paper, we propose a methodology which employs ‘hybrid data’ as a tool to analyse the fault tree. The proposed methodology estimates the failure probability of basic events using the statistical analysis of field recorded failures. Under these circumstances, where there is an absence of past failure records, the method follows a fuzzy set based theoretical evaluation based on the subjective judgement of experts for the failure interval. The proposed methodology has been applied to a conveyor system. The results of the analysis reveal the effectiveness of the proposed methodology and the instrumental role played by the experience of experts in providing reliability oriented information. Copyright © 2006 John Wiley & Sons, Ltd.
Strategies to avoid false negative findings in residue analysis using liquid chromatography coupled to time‐of‐flight mass spectrometry
Authors: Kaufmann Anton , Butcher Patrick
Published: November 2006

Liquid chromatography coupled to orthogonal acceleration time‐of‐flight mass spectrometry (LC/TOF) provides an attractive alternative to liquid chromatography coupled to triple quadrupole mass spectrometry (LC/MS/MS) in the field of multiresidue analysis. The sensitivity and selectivity of LC/TOF approach those of LC/MS/MS. TOF provides accurate mass information and a significantly higher mass resolution than quadrupole analyzers. The available mass resolution of commercial TOF instruments ranging from 10 000 to 18 000 full width at half maximum (FWHM) is not, however, sufficient to completely exclude the problem of isobaric interferences (co‐elution of analyte ions with matrix compounds of very similar mass). Due to the required data storage capacity, TOF raw data is commonly centroided before being electronically stored. However, centroiding can lead to a loss of data quality. The co‐elution of a low intensity analyte peak with an isobaric, high intensity matrix compound can cause problems. Some centroiding algorithms might not be capable of deconvoluting such partially merged signals, leading to incorrect centroids.

Co‐elution of isobaric compounds has been deliberately simulated by injecting diluted binary mixtures of isobaric model substances at various relative intensities. Depending on the mass differences between the two isobaric compounds and the resolution provided by the TOF instrument, significant deviations in exact mass measurements and signal intensities were observed. The extraction of a reconstructed ion chromatogram based on very narrow mass windows can even result in the complete loss of the analyte signal. Guidelines have been proposed to avoid such problems. The use of sub‐2 µm HPLC packing materials is recommended to improve chromatographic resolution and to reduce the risk of co‐elution. The width of the extraction mass windows for reconstructed ion chromatograms should be defined according to the resolution of the TOF instrument. Alternative approaches include the spiking of the sample with appropriate analyte concentrations. Furthermore, enhanced software, capable of deconvoluting partially merged mass peaks, may become available. Copyright © 2006 John Wiley & Sons, Ltd.
Impact of heavy metals and PCBs on marine picoplankton
Authors: Caroppo Carmela , Stabili Loredana , Aresta Michele , Corinaldesi Cinzia , Danovaro Roberto
Published: November 2006

Synergistic/antagonistic effects of multiple contaminants in marine environments are almost completely unexplored. In the present study, we investigated the effects of heavy metals (Zn and Pb) and PCBs on picoplankton abundance, biomass, cell size distribution, and bacterial C production. Natural picoplankton assemblages were exposed to heavy metals (Zn or Pb), organic contaminants (PCBs, Aroclor 1260), and to a mixture of different contaminants. The results of the present study indicate that Zn addition stimulated heterotrophic growth, whereas Pb has a negative impact on heterotrophic picoplankton, particularly significant in the first 24 h. Heavy metals had no effects on the autotrophic component. The addition of Aroclor 1260 had a significant impact on abundance, biomass, and cell size of autotrophic and heterotrophic picoplankton, and reduced significantly bacterial secondary production. Three weeks after PCB treatment, heterotrophic bacteria displayed a clear resilience, both in terms of abundance and biomass, reaching values comparable to those of the controls, but not in terms of bacterial C production. Our results indicate that picoplankton can be sensitive indicators of impact determined by heavy metals and PCBs in coastal marine systems. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 541–551, 2006.
Effect of methyl tert‐butyl ether in standard tests for mutagenicity and environmental toxicity
Authors: Vosahlikova Miluse , Cajthaml Tomas , Demnerova Katerina , Pazlarova Jarmila
Published: November 2006

Methyl tert‐butyl ether (MTBE) is a synthetic compound that is used as a technological solution to problems created by air pollution from vehicle emissions. An important source of MTBE in the environment is leakage from underground storage tanks at gasoline stations or accidents during gasoline transport. The aim of this study was to evaluate the risk of MTBE leakage for the environment using the Microtox® (Vibrio fischeri) toxicity test, Lactuca sativa seed germination test, and Ames bacterial mutagenicity test with Salmonella typhimurium his− strains TA98, TA100, YG1041, and YG1042, using both standard plate and preincubation protocols. The result of Microtox® expressed as EC50 was 33 mg (MTBE)/L. The effect of all tested MTBE concentration (0.05, 0.50, and 1.00% v/v) on Lactuca sativa roots elongation was negative and proved its toxicity. The highest tested concentration of MTBE that could be tested in Ames test was 3 mg (MTBE)/plate, because of cytotoxicity. No mutagenic response was observed at this or lower concentrations in any of the four strains used. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 599–605, 2006.
Kinetics of acyl migration in monoglycerides and dependence on acyl chainlength
Authors: Boswinkel G. , Derksen J. T. P. , van't Riet K. , Cuperus F. P.
Published: November 2006

The chemical rearrangement reaction of β‐ into α‐monoglycerides is described. Four monoglycerides with different fatty acid chainlength have been investigated, and the equilibrium constant and the reaction velocity constants characterizing the reaction of the chemical rearrangement were estimated with a mathematical model. A 1∶6.5 mixture of α/β‐monoglycerides appeared to rearrage to a mixture of 1∶1 α/β‐monoglycerides within 24 h. Furthermore, the reaction velocity of the rearrangement reaction of β‐ to α‐monoglycerides depended on the fatty acyl chainlength in the monoglyceride.
Supercritical fluid extraction of meat lipids: An alternative approach to the identification of irradiated meats
Authors: Hampson James W. , Jones Kerby C. , Foglia Thomas A. , Kohout Karen M.
Published: November 2006

Ionizing radiation is currently under study as an alternative method for extending the shelf life of meats and meat products. Accordingly, methods are needed to determine if a meat or meat product has been exposed to ionizing radiation. In this study, a method is described for the isolation and analysis of volatile hydrocarbons formed in meat lipids after exposure to ionizing radiation. The method is based on supercritical fluid extraction of the hydrocarbons from meat lipids and subsequent identification and quantitation of individual hydrocarbons by gas chromatography (GC) with a mass selection detector (MSD). Supercritical carbon dioxide at 175 bar and 40°C extracted the hydrocarbon fraction from total meat lipids within 20 min. The presence of radiolytic hydrocarbons, as determined by GC/MSD, was then correlated to the degree of irradiation of the meat from 0 to 10 kGy. Besides being faster, this method has the advantage of reduced solvent consumption when compared to current methods for determining if a meat or meat product has been irradiated.
Purification and characterization of a lipase fromNeurospora sp. TT‐241
Authors: Lin Shuen‐fuh , Lee Jane‐Chyi , Chiou Chien‐Ming
Published: November 2006

An extracellular lipase, which is produced by theNeurospora sp. TT‐241 strain, grown on wheat bran at 30°C for 4 d, was purified 370‐fold with an overall yield of 16%. The molecular weight was determined to be 55 kDa by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The optimal pH at 30°C and optimal temperature at pH 6.5 were 7 and 45°C, respectively. The lipase was stable in the pH range of 5 to 8, and it was temperature‐sensitive. It was active on a wide range of natural substrates of either vegetable or animal origins and towardp‐nitrophenyl esters, greatly favoring those containing C4 acyl groups. It cleaved all of the ester bonds of triolein; however, the 1‐ or 3‐ester bond was the preferred target. A complete inhibition by diisopropyl fluorophosphate suggested the presence of a serine residue at the active site. Partial inhibition was shown by either Hg2+ or chloramine T. Enzyme activity persisted in nonionic surfactants, a water‐miscible solvent (dimethylsulfoxide), and a water‐immiscible solvent (hexane).
Droplet composition affects the rate of oxidation of emulsified ethyl linoleate
Authors: Coupland J. N. , Zhu Z. , Wan H. , McClements D. J. , Nawar W. W. , Chinachoti P.
Published: November 2006

Our objective was to study the influence of droplet composition on the rate of lipid oxidation in emulsions. A series of oil‐in‐water emulsions stabilized by a nonionic surfactant (Tween 20) was studied. These emulsions had the same total oil concentration (5 wt%) and initial droplet diameter (0.3 μm), but contained droplets with different ratios of ethyl linoleate (substrate) andn‐tetradecane (inert diluent). Lipid oxidation was measured as a function of time by three different methods: gas‐chromatographic determination of residual substrate; ultraviolet‐visible spectrophotometric determination of conjugated dienes; and measurement of aqueous thiobarbituric acid‐reactive substances. All three methods showed similar trends for emulsions of similar composition. The progress of lipid oxidation in the emulsions was dependent on the concentration of ethyl linoleate in the emulsion droplets. At low concentrations (1% oil as substrate), oxidation proceeded at a relatively slow and constant rate. At intermediate concentrations (20%), the oxidation rate was rapid initially and then slowed down with time. At high concentrations (100%), the oxidation rate was slow at first, and then increased with time. An explanation of our results is proposed in terms of the distribution of substrate molecules between the droplet interior and interface, and the ingress of aqueous radicals into the emulsion droplets.
Characteristic properties of cutting fluid additives derived from half esters of dimer acids
Authors: Watanabe S. , Nakagawa H. , Ohmori Y. , Fujita T. , Sakamoto M. , Haga T.
Published: November 2006

A number of half esters were prepared from the reaction of alcohols with dimer acids and screened for anti‐rust properties and antimicrobial activity in spent coolants of water‐based cutting fluids. Aqueous solutions of triethanolamine salts with lower‐alcohol half esters of dimer acid showed good anti‐rust properties for water‐based cutting fluids.
Syntheses of long‐chain quaternary ammonium salts from fatty alcohols by microwave irradiation
Authors: Jiang Yu‐Lin , Hu Yu‐Qiao , Pang Jun , Yuan Yun‐Cheng
Published: November 2006

The phase‐transfer catalysts, long‐chain quaternary ammonium salts, were rapidly synthesized from fatty alcohols by the reactions with hydrogen halides in the presence of trialkyl amines under microwave irradiation. The catalysts could be widely applied in a variety of quick and new organic reactions, whether by conventional heating or under microwave irradiation. The reaction efficiencies under microwave irradiation were higher than those obtained with conventional heating.
Surface‐tension properties of some polydispersed alkyl‐substituted polyoxyethylated phenylsulfonamides
Authors: Hampson J. W. , Cornell D. G.
Published: November 2006

Twenty‐nine laboratory‐prepared polydisperse nonionic surfactants, derived from polyoxyethylatedN‐alkylphenylsulfonamides [RϕSO2 N(R′) (EO)nH], have been characterized. EO is ethyoxylation;R is hydrogen,n‐butyl ort‐butyl;R′ is hexyl, octyl, or decyl; and (EO)n is varied from (EO)4 to (EO)20. Surface tension in aqueous solution was studied. The critical micelle concentration, surface excess, minimum area per molecule, effectiveness of surface‐tension reduction, and free energy of micelle formation were calculated from the surface‐tension measurements. The critical micelle concentrations for the derivatives in whichR′‐hexyl were considerably higher than the corresponding derivatives whereR′ is octyl or decyl. The greatest surface‐tension reduction was found in theR′=n‐octyl derivatives whereR ist‐butyl with (EO)9 orn‐butyl with (EO)11.
Pushing the frontiers of multicultural training in community psychology
Authors: Weinstein Rhona S.
Published: November 2006

Suarez‐Balcazar, Durlak, and Smith (1994) have provided the field with important baseline information regarding multicultural training practices in community psychology. This report can serve as a catalyst in our quest to place an understanding of human diversity, in particular, ethnic‐cultural diversity, at the heart of community psychology. To do so, we need to move beyond the teaching of culturally sensitive research and practice to a reconceptualization of the knowledge base and methods of community psychology, to an examination of the conflicts engendered by the inclusion of multiple voices, and to the implementation of institutional arrangements that can support such a challenging task in constructive ways.
Purification and characterization of deep sea sharkCentrophorus squamosus liver oil 1‐O‐aklylglycerol ether lipids
Authors: Bordier Catherine G. , Sellier Nicole , Foucault Alain P. , Le Goffic François
Published: November 2006

The 1‐O‐alkylglycerol composition of the liver oil of the deep sea sharkCentrophorus squamosus, a species which provides edible flesh, has been determined. After various fractionations of the oil, the unsaponifiable fraction was characterized by means of gas chromatography/mass spectrometry, electron impact, and positive‐ion chemical ionization. The oil is composed of 60% unsaponifiable matter, containing 45% squalene, 4.5% cholesterol, and 10% of linear saturated and monounsaturated glycerol ethers with 14–18 carbon atoms. After a first separtion by chromatography on silicic acid, monounsaturated glycerol ethers have been separated from the saturated homologues, in particular from 1‐O‐octadecylglycerol (batyl alcohol) and 1‐O‐hexadecylglycerol (chimyl alcohol)via urea complexation. This newer application of the urea method, already used in the past to extract saturated from polyunsaturated fatty acids, allowed the purification of the main components of the complex unsaturated glycerol ether fraction, namely, 1‐O‐octadecen‐9′ylglycerol (selachyl alcohol) and 1‐O‐hexadecen‐9′ylglycerol.
Microscale preparation of natural and labeled oxysterols
Authors: Krut Louis H. , Schonfeld Gustav , Ostlund Richard E.
Published: November 2006

The preparation of cholesterol and radiocholesterol oxidation products on a microscale is difficult. Cholesterol generally resists oxidation unless it is well dispersed under controlled conditions. A method was developed to reliably produce 7α‐ and 7β‐hydroxycholesterol and 7‐ketocholesterol. Small changes in pH, metal ions present, or in the colloidal dispersion, resulted in production of completely different oxysterols. Attempts to oxidize aged radiocholesterol were not successful even after purification by several thin‐layer chromatographic steps, and this appeared to be due to a time‐related change in the radioactive material. Fresh radiocholesterol oxidized readily.