bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly diffusion‐sensitized MRI of brain: Dissociation of gray and white matter
Authors: Yoshiura Takashi , Wu Ona , Zaheer Atif , Reese Timothy G. , Sorensen A. Gregory
Published: September 2002

The brains of six healthy volunteers were scanned with a full tensor diffusion MRI technique to study the effect of a high b value on diffusion‐weighted images (DWIs). The b values ranged from 500 to 5000 s/mm2. Isotropic DWIs, trace apparent diffusion coefficient (ADC) maps, and fractional anisotropy (FA) maps were created for each b value. As the b value increased, ADC decreased in both the gray and white matter. Furthermore, ADC of the white matter became lower than that of the gray matter, and, as a result, the white matter became brighter than the gray matter in the isotropic DWIs. Quantitative analysis showed that these changes were due to nonmonoexponential diffusion signal decay of the brain tissue, which was more prominent in white matter than in gray matter. There was no significant change in relation to the b value in the FA maps. High b value appears to have a dissociating effect on gray and white matter in DWIs. Magn Reson Med 45:734–740, 2001. © 2001 Wiley‐Liss, Inc.
Analysis of partial volume effects in diffusion‐tensor MRI
Authors: Alexander Andrew L. , Hasan Khader M. , Lazar Mariana , Tsuruda Jay S. , Parker Dennis L.
Published: September 2002

The diffusion tensor is currently the accepted model of diffusion in biological tissues. The measured diffusion behavior may be more complex when two or more distinct tissues with different diffusion tensors occupy the same voxel. In this study, a partial volume model of MRI signal behavior for two diffusion‐tensor compartments is presented. Simulations using this model demonstrate that the conventional single diffusion tensor model could lead to highly variable and inaccurate measurements of diffusion behavior. The differences between the single and two‐tensor models depend on the orientations, fractions, and exchange between the two diffusion tensor compartments, as well as the diffusion‐tensor encoding technique and diffusion‐weighting that is used in the measurements. The current single compartment model's inaccuracies could cause diffusion‐based characterization of cerebral ischemia and white matter connectivity to be incorrect. A diffusion‐tensor MRI imaging experiment on a normal human brain revealed significant partial volume effects between oblique white matter regions when using very large voxels and large diffusion‐weighting (b ∼ 2.69 × 103 sec/mm2). However, the apparent partial volume effects in white matter decreased significantly when smaller voxel dimensions were used. For diffusion tensor studies obtained using typical diffusion‐weighting values (b ∼ 1 × 103 sec/mm2) partial volume effects are much more difficult to detect and resolve. More accurate measurements of multiple diffusion compartments may lead to improved confidence in diffusion measurements for clinical applications. Magn Reson Med 45:770–780, 2001. © 2001 Wiley‐Liss, Inc.
Three‐dimensional subzone‐based reconstruction algorithm for MR elastography
Authors: Van Houten Elijah E.W. , Miga Michael I. , Weaver John B. , Kennedy Francis E. , Paulsen Keith D.
Published: September 2002

Accurate characterization of harmonic tissue motion for realistic tissue geometries and property distributions requires knowledge of the full three‐dimensional displacement field because of the asymmetric nature of both the boundaries of the tissue domain and the location of internal mechanical heterogeneities. The implications of this for magnetic resonance elastography (MRE) are twofold. First, for MRE methods which require the measurement of a harmonic displacement field within the tissue region of interest, the presence of 3D motion effects reduces or eliminates the possibility that simpler, lower‐dimensional motion field images will capture the true dynamics of the entire stimulated tissue. Second, MRE techniques that exploit model‐based elastic property reconstruction methods will not be able to accurately match the observed displacements unless they are capable of accounting for 3D motion effects. These two factors are of key importance for MRE techniques based on linear elasticity models to reconstruct mechanical tissue property distributions in biological samples. This article demonstrates that 3D motion effects are present even in regular, symmetric phantom geometries and presents the development of a 3D reconstruction algorithm capable of discerning elastic property distributions in the presence of such effects. The algorithm allows for the accurate determination of tissue mechanical properties at resolutions equal to that of the MR displacement image in complex, asymmetric biological tissue geometries. Simulation studies in a realistic 3D breast geometry indicate that the process can accurately detect 1‐cm diameter hard inclusions with 2.5× elasticity contrast to the surrounding tissue. Magn Reson Med 45:827–837, 2001. © 2001 Wiley‐Liss, Inc.
Accurate multislice gradient echo T1 measurement in the presence of non‐ideal RF pulse shape and RF field nonuniformity
Authors: Parker Geoffrey J.M. , Barker Gareth J. , Tofts Paul S.
Published: September 2002

A methodology is presented for estimating T1 using a two‐point technique with a standard multislice gradient echo sequence. The method explicitly corrects for the shape of the RF pulse and for spatial variations in transmitted RF field intensity. Including these factors in the calculation of T1 gives a substantial improvement in accuracy and precision of two‐point gradient echo T1 measurements in the presence of RF nonuniformity and non‐ideal pulse profiles. The mean accuracy of the technique was found to be 1.4%. The mean precision was found to be 3.0%. The mean variation along the axis of a head coil was found to be 2.3%. Magn Reson Med 45:838–845, 2001. © 2001 Wiley‐Liss, Inc.
Adaptive sensitivity encoding incorporating temporal filtering (TSENSE)†
Authors: Kellman Peter , Epstein Frederick H. , McVeigh Elliot R.
Published: September 2002

A number of different methods have been demonstrated which increase the speed of MR acquisition by decreasing the number of sequential phase encodes. The UNFOLD technique is based on time interleaving of k‐space lines in sequential images and exploits the property that the outer portion of the field‐of‐view is relatively static. The differences in spatial sensitivity of multiple receiver coils may be exploited using SENSE or SMASH techniques to eliminate the aliased component that results from undersampling k‐space. In this article, an adaptive method of sensitivity encoding is presented which incorporates both spatial and temporal filtering. Temporal filtering and spatial encoding may be combined by acquiring phase encodes in an interleaved manner. In this way the aliased components are alternating phase. The SENSE formulation is not altered by the phase of the alias artifact; however, for imperfect estimates of coil sensitivities the residual artifact will have alternating phase using this approach. This is the essence of combining temporal filtering (UNFOLD) with spatial sensitivity encoding (SENSE). Any residual artifact will be temporally frequency‐shifted to the band edge and thus may be further suppressed by temporal low‐pass filtering. By combining both temporal and spatial filtering a high degree of alias artifact rejection may be achieved with less stringent requirements on accuracy of coil sensitivity estimates and temporal low‐pass filter selectivity than would be required using each method individually. Experimental results that demonstrate the adaptive spatiotemporal filtering method (adaptive TSENSE) with acceleration factor R = 2, for real‐time nonbreath‐held cardiac MR imaging during exercise induced stress are presented. Magn Reson Med 45:846–852, 2001. Published 2001 Wiley‐Liss, Inc.
Lumbrical and interossei recording in severe carpal tunnel syndrome
Authors: Boonyapisit Kanokwan , Katirji Bashar , Shapiro Barbara E , Preston David C.
Published: September 2002

Patients with severe carpal tunnel syndrome (CTS) may occasionally have absent median motor and sensory responses; in these cases, it is not possible to accurately localize the median mononeuropathy to the wrist using standard electrodiagnostic tests. We prospectively investigated the use of comparing the median motor latency to the second lumbrical and the ulnar motor latency to the interossei muscles in 28 patient hands with severe CTS and absent median motor and sensory responses. We found a prolonged latency difference in 92.8%. Along with its use in mild CTS, study of the lumbrical‐interossei latency difference is helpful in patients with severe CTS with absent median motor and sensory responses. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 102–105, 2002
Magnetization transfer MRS
Authors: Leibfritz Dieter , Dreher Wolfgang
Published: September 2002

This review deals with magnetization transfer (MT) effects observed in in vivo NMR spectroscopy. The basic experimental methods of MT experiments, the underlying kinetic mechanisms as well as the evaluation of measured data by fits to two‐ or three‐pool models are described. Experimental results of both 31P and 1H in vivo MRS are reviewed showing the potential of MT experiments to characterize kinetic equilibrium reactions. This includes reactions where all involved components are MR visible, as well as situations where one indirectly measures pools of bound spins which cannot directly be observed in vivo. In particular, MT effects are described which have been observed in in vivo 1H NMR spectra measured on the animal or human brain or on skeletal muscle. Possible mechanisms for the strong MT effects observed for the signals of creatine/phosphocreatine, lactate, alcohol and other metabolites are discussed. It is also emphasized that MT effects caused by water suppression techniques may lead to systematic errors in the quantification of in vivo 1H NMR spectra. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

CIDNP

chemically induced nuclear polarization

NOE

nuclear Overhauser effect

SNR

signal‐to‐noise ratio

TRABI

train of bipolar pulses

2D EXSY

two‐dimensional exchange spectroscopy

MEGA

Mescher–Garwood water suppression

WEFT

water‐eliminated Fourier technique

rf

radio frequency

cw

continuous wave.
Relaxation times and microstructures
Authors: Fenrich F. R. E. , Beaulieu C. , Allen P. S.
Published: September 2002

A discussion is presented of the evaluation of multiple relaxation components from water protons in biological tissue. The principal focus is to draw attention to the way in which limitations in the raw NMR data, such as signal‐to‐noise ratio, data sampling density and acquisition window width, affect the precision and resolution in the processed multiple component solution of the return to thermal equilibrium. The second issue discussed is the interpretation of these multiple components in terms of microstructural compartments of the biological sample and, thirdly, we outline some of the successes in determining regional and pathological variations in microstructure in the human body in‐vivo, using the technique of multiple relaxation components. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

CNS

central nervous system

CPMG

Carr–Purcell–Meiboom–Gill sequence

RBC

red blood cells

NMR

nuclear magnetic resonance

NNLS

non‐negative least squares

PNS

peripheral nervous system

SNR

signal‐to‐noise ratio

TE

echo time.
MR spectroscopy quantitation: a review of time‐domain methods
Authors: Vanhamme Leentie , Sundin Tomas , Hecke Paul Van , Huffel Sabine Van
Published: September 2002

In this article an overview of time‐domain quantitation methods is given. Advantages of processing the data in the measurement domain are discussed. The basic underlying principles of the methods are outlined and from them the situations under which these algorithms perform well are derived. Also an overview of methods to preprocess the data is given. In that respect, signal‐to‐noise and/or resolution enhancement, the removal of unwanted components and corrections for model imperfections are discussed. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ARMA

autoregressive moving average

ATP

adenosine triphosphate

EM

expectation ‐ maximization

FIR

finite impulse response

IQML

iterative quadratic maximum likelihood method

ML

maximum likelihood

MP

matrix pencil

NLLS

nonlinear least squares

PCA

principal component analysis

SVD

singular value decomposition

TLS

total least squares.
Automatic quantitation of localized in vivo1H spectra with LCModel
Authors: Provencher Stephen W.
Published: September 2002

The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model in vitro spectra from individual metabolite solutions. Complete model spectra, rather than individual resonances, are used in order to incorporate maximum prior information into the analysis. A nearly model‐free constrained regularization method automatically accounts for the baseline and lineshape in vivo without imposing a restrictive parameterized form on them. LCModel is automatic (non‐interactive) with no subjective input. Approximately maximum‐likelihood estimates of the metabolite concentrations and their uncertainties (Cramér‐Rao lower bounds) are obtained. LCModel analyses of spectra from users with fields from 1.5 to 9.4 T and a wide range of sequences, particularly with short TE, are used here to illustrate the capabilities and limitations of LCModel and proton MRS. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

Ala

alanine

Asp

aspartate

Cr

creatine

GABA

γ‐aminobutyric acid

Glc

glucose

Gln

glutamine

Glu

glutamate

GPC

glycerophosphocholine

GSH

glutathione

Ins

myo‐inositol

Lac

lactate

NAA

N‐acetylaspartate

NAAG

N‐acetylaspartylglutamate

PC

phosphocholine

PCr

phosphocreatine

PE

phosphoethanolamine

Scyllo

scyllo‐inositol

S/N

signal‐to‐noise ratio

Tau

taurine.
Enteric neuroblasts require the phosphatidylinositol 3‐kinase pathway for GDNF‐stimulated proliferation
Authors: Focke Paul J. , Schiltz Craig A. , Jones Sharon E. , Watters Jyoti J. , Epstein Miles L.
Published: September 2002

The enteric nervous system (ENS) develops from neural crest cells that enter the gut, migrate, proliferate, and differentiate into neurons and glia. The growth factor glial‐derived neurotrophic factor (GDNF) stimulates the proliferation and survival of enteric crest‐derived cells. We investigated the intracellular signaling pathways activated by GDNF and their involvement in proliferation. We found that GDNF stimulates the phosphorylation of both the PI 3‐kinase downstream substrate Akt and the MAP kinase substrate ERK in cultures of immunoaffinity‐purified embryonic avian enteric crest‐derived cells. The selective PI 3‐kinase inhibitor LY‐294002 blocked GDNF‐stimulated Akt phosphorylation in purified crest cells, and reduced proliferation in cultures of dissociated quail gut. The ERK kinase (MEK) inhibitors PD 98059 and UO126 did not reduce GDNF‐stimulated proliferation, although PD 98059 blocked GDNF‐stimulated phosphorylation of ERK. We conclude that the PI 3‐kinase pathway is necessary for the GDNF‐stimulated proliferation of enteric neuroblasts. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 306–317, 2001
Prenatal diagnosis of a de novo supernumerary marker derived from chromosome 16
Authors: Hengstschläger Markus , Bettelheim Dieter , Drahonsky Regina , Deutinger Josef , Bernaschek Gerhard
Published: September 2002

Marker chromosomes are supernumerary chromosomes of unknown origin and are seldom found in prenatal diagnosis. Application of fluorescent in situ hybridization (FISH) allows the identification of the chromosomal origin of markers. Estimation of the risk of an abnormal phenotype outcome can be enabled by collecting data on phenotypes associated with markers of the same chromosomal origin. So far only very few cases of prenatal diagnosis of de novo supernumerary markers derived from chromosome 16 have been reported. Here the prenatal diagnosis of a de novo supernumerary marker chromosome 16 is described and the relevant literature discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Micellar effect on the reaction of chromium(VI) oxidation of D‐fructose in the presence and absence of picolinic acid in aqueous media: a kinetic study
Authors: Das Asim K. , Roy Aparna , Saha Bidyut , Mohanty Rajani K. , Das Mahua
Published: September 2002

The kinetics and mechanism of the Cr(VI) oxidation of D‐fructose in the presence and absence of picolinic acid (PA) in aqueous acid media were studied under the conditions [D‐fructose]T ≫[Cr(VI)]T at different temperatures. Under the kinetic conditions, the monomeric species of Cr(VI) was found to be kinetically active in the absence of PA whereas in the PA‐catalysed path, the Cr(VI)–PA complex was considered to be the active oxidant. In this path, the Cr(VI)–PA complex undergoes a nucleophilic attack by the substrate to form a ternary complex which subsequently experiences a redox decomposition through glycol splitting leading to the lactone of C5‐aldonic acid along with formaldehyde and the Cr(IV)–PA complex. The primary product formaldehyde undergoes further oxidation (in part) to form formic acid. Then the Cr(IV)–PA complex participates further in the oxidation of D‐fructose and ultimately is converted into the inert Cr(III)–PA complex. In the uncatalysed path, the Cr(VI)–substrate ester experiences an acid‐catalysed redox decomposition (2e transfer) in the rate‐determining step giving rise to the products. The uncatalysed path shows a second‐order dependence on [H+] whereas the PA catalysed path shows a fractional order in [H+]. Both paths show a first‐order dependence on [D‐fructose]T and [Cr(VI)]T. The PA‐catalysed path is first order in [PA]T. All these patterns remain unaltered in the presence of externally added surfactants. The effects of a cationic surfactant, N‐cetylpyridinium chloride (CPC), and an anionic surfactant, sodium dodecyl sulfate (SDS), on both the uncatalysed and PA‐catalysed paths were studied. CPC inhibits both the uncatalysed and PA‐catalysed paths whereas SDS catalyses the reactions. The observed micellar effects are explained by considering a distribution pattern of the reactants between the micellar and aqueous phases. The applicability of different kinetic models, e.g. the pseudo‐phase ion‐exchange model, the Menger–Portnoy model and the Piszkiewicz cooperative model, was tested to explain the observed micellar effects. The effect of [surfactant]T on the activation parameters was explored to rationalize the micellar effect. Copyright © 2001 John Wiley & Sons, Ltd.
Psychosocial interventions for cancer: review and analysis using a three‐tiered outcomes model
Authors: Owen Jason E. , Klapow Joshua C. , Hicken Bret , Tucker Diane C.
Published: September 2002

This study describes a three‐tiered measurement model for psychosocial interventions with cancer patients and compares this model to extant measurement strategies. Progress has been made toward demonstrating that psychosocial interventions reduce depression, anxiety, functional impairment, and symptoms. However, Chambless and Hollon (1998) note that the literature on psychosocial interventions for cancer fails to meet criteria for establishing treatment ‘efficacy’ and does not address issues of cost‐effectiveness. The lack of a timely model of clinical outcomes may be hindering demonstration of efficacy and wider implementation of these interventions. Outcomes assessed by 65 interventions were classified as Global Health Outcomes (medical endpoints, health‐related quality of life (HRQOL), or resource utilization), Dimensions of HRQOL (distress, symptoms, functional ability, or interpersonal well‐being), or Mechanisms of Action (evaluation of psychological or physiological processes). A total of 28% of reviewed studies assessed Global Outcomes, 82% assessed Dimensions of HRQOL, and 49% assessed Mechanisms of Action. While most studies assessed patients' symptoms and distress, measurements of resource utilization, HRQOL, and interpersonal HRQOL were under‐reported. A greater emphasis on treatment costs, quality of life, and mediating/moderating processes associated with improvement in outcomes could inform decisions regarding allocation of health‐care resources and lead to more widely available and efficient interventions for patients. Copyright © 2001 John Wiley & Sons, Ltd.
Supportive groups for siblings of pediatric oncology patients: impact on anxiety
Authors: Houtzager B.A. , Grootenhuis M.A. , Last B.F.
Published: September 2002

Childhood cancer can have a substantial emotional impact on the siblings of the sick child. In order to help these siblings adjust to the illness, supportive groups were started in 1994 at our medical center. The program is based on a model of psychosocial support; the aim of the group is to enhance control strategies and, thus, to reduce anxiety. It consists of five sessions and is offered to siblings aged 7–18. The study objective is to evaluate the effect of group participation on sibling anxiety. The State Trait Anxiety Inventory for Children was administered to 24 siblings before and after group participation.

Results showed that siblings experience less anxiety after participating in the group. Before group participation, a majority of the siblings were more anxious compared with normal peers. The sibling's age and sex, whether the ill child is in treatment, survival perspective, and time since diagnosis were not related to anxiety reduction. The continuation of the group is supported by its positive impact on siblings. Results must nevertheless be interpreted cautiously, considering the small number of siblings participating in the study, the lack of a control group and the restriction to one outcome measure. Copyright © 2001 John Wiley & Sons, Ltd.
Parental coping with the diagnosis of childhood cancer: gender effects, dissimilarity within couples, and quality of life
Authors: Goldbeck Lutz
Published: September 2002

Objective: Considering coping as dynamic process within the family, effects of gender and diagnosis are investigated. Dissimilarity within couples in coping with childhood cancer is studied longitudinally in its effects on quality of life of mothers, fathers, and the sick children.

Methods: A total of 108 parents out of 54 complete families participated in a prospective study. Twenty‐five families had a child newly diagnosed with cancer, 29 families had a child newly diagnosed with juvenile diabetes or epilepsy. The Coping Health Inventory for Parents, the Trier Coping Scales, and the Ulm Quality‐of‐Life Inventory for Parents were employed 1–2 weeks after diagnosis and again 10–12 weeks after diagnosis.

Results: In face of childhood cancer, parents develop more rumination, defense, and information seeking, and less social support seeking strategies compared to the control group. Mothers report more frequent and more effective coping compared with fathers, but mothers and fathers do not differ in their self‐reported quality of life. No convergence within couples could be demonstrated in most of the corresponding coping styles. The strongest correlation between mothers and fathers appeared in the religious coping style (r=0.60, p<0.001). Coping dissimilarity within couples in social support seeking and religion is correlated with an improvement of parental quality of life. Parental dissimilarity in information seeking is correlated with a decrease in the child's quality of life.

Conclusion: Coping dissimilarities between fathers and mothers have differential effects on the family members. For this reason, psychosocial interventions should support dis‐synchrony when it appears adaptive, and they should help parents to overcome those differences that negatively affect their child. Copyright © 2001 John Wiley & Sons, Ltd.
Increased serum insulin associated with increased risk of prostate cancer recurrence
Authors: Lehrer Steven , Diamond Edward J. , Stagger Sharodka , Stone Nelson N. , Stock Richard G.
Published: September 2002

BACKGROUND

In the present study, we assessed the relationship of serum insulin levels and risk of recurrence in men with localized prostate cancer because of the relationship of insulin to the development of prostate cancer, and because insulin is a growth factor.

METHODS

Participants in our study were found through urology and radiation oncology clinics, and all eligible patients were asked to take part. All patients were asymptomatic and had been initially diagnosed on the basis of rising PSA or abnormal physical examination. Histological confirmation of diagnosis was obtained for all subjects. Serum insulin levels were determined by chemoluminescent assay with a standard, commercially available instrument (Immulite Diagnostic Products Corporation, Los Angeles, CA). Patients were divided into three risk groups: Low risk: serum PSA ≤ 10, stage ≤ T2a, or Gleason grade ≤ 6; Medium risk: serum PSA 10–15, Gleason 7 or stage ≤ T2b; High risk: Gleason > 7, tumor in seminal vesicle biopsy, serum PSA > 15 or stage T2c or T3.

RESULTS

Men, 112 in number, with prostate cancer were studied. There was a significant increase in serum insulin with risk group (P = 0.002, one‐way ANOVA). Tukey's multiple range test showed that the insulin levels of high risk patients were significantly higher than the insulin levels of medium and low risk patients (P = 0.05) but the insulin levels of medium and low risk patients were not significantly different from one another.

CONCLUSIONS

Urologists are actively seeking additional biomarkers of prostate cancer aggressiveness. Many prostate cancers are quite indolent and may never cause a problem, but it is now impossible to identify such tumors with certainty. Further studies of serum insulin levels in prostate cancer as a biomarker might, therefore, be worthwhile. With more and better biomarkers, many older men might be spared the rigors of radiation therapy and/or surgery, and their complications. Also, new prostate cancer therapies might be directed toward inhibiting the mitogenic effects of insulin. Prostate 50: 1–3, 2002. © 2002 Wiley‐Liss, Inc.
Mechanism of estrogens‐induced increases in intracellular Ca2+ in PC3 human prostate cancer cells
Authors: Huang Jong‐Khing , Jan Chung‐Ren
Published: September 2002

BACKGROUND

The effect of estrogens (diethylstilbestrol [DES], 17β‐estradiol) on intracellular Ca2+ concentrations ([Ca2+]i) in hormone‐insensitive PC3 human prostate cancer cells was examined.

METHODS

[Ca2+]i changes in suspended cells were measured by using the Ca2+‐sensitive fluorescent dye fura‐2.

RESULTS

Estrogens (1–20 μM) increased [Ca2+]i concentration‐dependently with DES being more potent. Ca2+ removal inhibited 50 ± 10% of the signal. In Ca2+‐free medium, pretreatment with 20 μM estrogens abolished the [Ca2+]i increases induced by 2 μM carbonylcyanide m‐chlorophenylhydrazone (CCCP, a mitochondrial uncoupler) and 1 μM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), but pretreatment with CCCP and thapsigargin did not alter DES‐induced Ca2+ release and partly inhibited 17β‐estradiol‐induced Ca2+ release. Addition of 3 mM Ca2+ increased [Ca2+]i in cells pretreated with 1– 20 μM estrogens in Ca2+‐free medium. Pretreatment with 1 μM U73122 to block phospholipase C‐coupled inositol 1,4,5‐trisphosphate formation did not alter estrogens‐induced Ca2+ release. The effect of 20 μM estrogen on [Ca2+]i was not affected by pretreatment with 0.1 μM estrogens.

CONCLUSIONS

Estrogen induced significant Ca2+ release and Ca2+ influx in an inositol 1,4,5‐trisphosphate‐independent manner in PC3 cells. These effects of estrogens on Ca2+ signaling appear to be nongenomic. Prostate 47:141–148, 2001. © 2001 Wiley‐Liss, Inc.
Mxi1, a Myc antagonist, suppresses proliferation of DU145 human prostate cells
Authors: Taj Mary M. , Tawil Rana J. , Engstrom Lars D. , Zeng Zhi , Hwang Clara , Sanda Martin G. , Wechsler Daniel S.
Published: September 2002

BACKGROUND

Mxi1, an antagonist of c‐Myc, maps to human chromosome 10q24‐q25, a region altered in a substantial fraction of prostate tumors. Mice deficient for Mxi1 exhibit significant prostate hyperplasia. We studied the ability of Mxi1 to act as a growth suppressor in prostate tumor cells.

METHODS

We infected DU145 prostate carcinoma cells with an Mxi1‐expressing adenovirus (AdMxi1) in vitro, and measured Mxi1 expression, cell proliferation, soft agar colony formation, and cell cycle distribution. To explore mechanisms of Mxi1‐induced growth arrest, we performed gene expression analysis.

RESULTS

AdMxi1 infection resulted in reduced cell proliferation, reduced soft agar colony formation, and a higher proportion of cells in the G2/M phase of the cell cycle. This G2/M growth arrest was associated with elevated levels of cyclin B, and reduced levels of c‐MYC and MDM2.

CONCLUSIONS

The ability of AdMxi1 to suppress prostate tumor cell proliferation supports a role for Mxi1 loss in the pathogenesis of a subset of human prostate cancers. Prostate 47:194–204, 2001. © 2001 Wiley‐Liss, Inc.
Development of a water‐soluble preparation of emamectin benzoate and its preventative effect against the wilting of pot‐grown pine trees inoculated with the pine wood nematode, Bursaphelenchus xylophilus
Authors: Takai Kazuya , Soejima Tomoyuki , Suzuki Toshio , Kawazu Kazuyoshi
Published: September 2002

Water‐soluble preparations have been investigated to develop a trunk injection agent based on the poorly water‐soluble anti‐nematode emamectin benzoate. Following tests on the phytotoxicity of some solvents and solubilizers and demonstration of the ability of some solubilizers to dissolve emamectin benzoate in water, acetone + methanol was selected as the solvent and Polysorbate 80 as the solubilizer. This water‐soluble preparation of emamectin benzoate prevented the wilting of pot‐grown 4‐year‐old trees of the Japanese black pine, Pinus thunbergii, artificially inoculated with the pine wood nematode, Bursaphelenchus xylophilus, at a dose of 20 g emamectin benzoate per cubic metre of pine tree.

© 2001 Society of Chemical Industry
Incidence and inheritance of resistance to METI‐acaricides in European strains of the two‐spotted spider mite (Tetranychus urticae) (Acari: Tetranychidae)
Authors: Devine Gregor J , Barber Mat , Denholm Ian
Published: September 2002

A strain of Tetranychus urticae (Koch; Acari: Tetranychidae), collected from hops (Humulus humuli L; Cannabaceae) in England with a short history of tebufenpyrad use, exhibited resistance to four METI (mitochondrial electron transport inhibitor)‐acaricides; tebufenpyrad, pyridaben, fenazaquin and fenpyroximate. Resistance factors for these compounds in a micro‐immersion assay were 46, 346, 168 and 77 respectively, and corresponded to those exhibited by a Japanese METI‐acaricide‐resistant reference strain. Levels of resistance remained stable without further selection, and selection with tebufenpyrad did not increase them. The UK strain was also resistant (c 6‐fold) to bifenthrin. Crosses of homozygous, diploid females with hemizygous, haploid males showed that, in the UK strain, METI‐acaricide resistance was paternally and maternally inherited, and was an incompletely dominant trait. Another tebufenpyrad‐resistant strain from the UK, originating from a chrysanthemum nursery (Chrysanthemum foeniculaceum Giseke; Asteraceae) was collected eight months later at a site c 210 km distant from the first. These are the first published incidences of METI‐acaricide resistance in Europe and implications for the future use of these compounds are discussed.

© 2000 Society of Chemical Industry
Reliability methods in earthquake engineering
Authors: Pinto Paolo Emilio
Published: September 2002

Methods for seismic reliability assessment are selectively reviewed, on the basis of their capability of providing, in their present form or in their foreseable state of development, a realistic measure of the total risk. Realism starts with description of the seismic input, which must be related to the main parameters of earthquake generation and wave propagation. It then involves structural models, which must be sufficiently accurate to incorporate physical measures of structural performance, to describe the actual sources of uncertainty, and to detect all important modes of failure. Finally, realism implies a degree of complexity of the method and computation which are acceptable to advanced engineering practice. As regards the input, it is argued that properly selected recorded accelerograms (and, in the future, possibly, synthetic accelerograms) satisfy the requirement of realism to a much higher degree than random processes and samples. The consequence of the use of accelerograms is that, whatever risk evaluation method is adopted, simulation is always necessary, in order to take account of sample‐to‐sample variability. Three main categories of method are distinguished: simulation‐based, FORM‐based (First Order Reliability Methods), and response‐surface‐based, although the boundaries between the three are often blurred. A number of different proposals for implementation exist in the literature within each category. A subjective selection has been made of two or three of these proposals for each category, as a means of describing the general approach in more detail and for discussing their essential limitations. The opinion is offered that the subject area of seismic risk assessment still presents great opportunities for development, both of a fundamental and an applied nature. It is encouraging to note that large efforts are being made internationally on both aspects, and that the profession is showing increasing consciousness of the importance of the approach and a willingness to introduce it into common engineering practice.
Multilayered antimicrobial polyethylene films applied to the packaging of ground beef
Authors: Ha Jung‐Uk , Kim Young‐Min , Lee Dong‐Sun
Published: September 2002

A natural antimicrobial agent, grapefruit seed extract (GFSE), was incorporated in a 0.5% or 1.0% concentration on the food‐contact surface of multilayered polyethylene (PE) film by a co‐extrusion or solution‐coating process. The fabricated films were tested in their antimicrobial activity against several food spoilage microorganisms, and then applied to the packaging of ground beef. During the storage of the packaged beef at 3°C, changes in microbial counts, pH, TBA value and meat colour were monitored in order to see the effect of the packaging film on meat quality changes. Coating the PE film with GFSE with the aid of a polyamide binder resulted in a more effective level of antimicrobial activity on the agar plate medium than did its incorporation by a co‐extrusion process. The film co‐extruded with a 1.0% GFSE layer showed antimicrobial activity only against Micrococcus flavus ATCC 10240, while the film coated with 1.0% GFSE showed activity against several microorganisms, such as Escherichia coli IFO 3301, Staphylococcus aureus IFO 3060 and Bacillus subtilis IFO 12113. Both types of GFSE‐incorporated multilayer PE films contributed to a reduction of the growth rates of aerobic and coliform bacteria on the ground beef, when compared to plain PE film. The film coated with a higher concentration (1.0%) of GFSE had a more pronounced effect than did the other films in inhibiting spoilage bacterial growth. They could also slow down chemical changes of the packaged beef. The GFSE‐coated film was more effective in preserving beef quality, but the level of GFSE addition did not affect the quality changes of the beef. Copyright © 2001 John Wiley & Sons, Ltd.
Theoretical study on quantum dynamics of bose system interacting with photon field
Authors: Nagao Hidemi , Nakano Masayoshi , Nishikawa Kiyoshi , Yamaguchi Kizashi
Published: September 2002

We investigate the quantum dynamics of two‐boson and two‐level systems interacting with a one‐mode photon field. The time evolution of the population for each state is calculated in terms of the Jaynes–Cummings model. We find the collapses and revivals of the order parameter for the Bose–Einstein condensation. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 401–408, 2001
QM/MM distortion energies in di‐ and oligosaccharides complexed with proteins*
Authors: French Alfred D. , Johnson Glenn P. , Kelterer Anne‐Marie , Dowd Michael K. , Cramer Christopher J.
Published: September 2002

To investigate whether linkages between monosaccharide residues are unusually distorted by their interactions with proteins, ϕ and ψ values for fragments of cellulose and starch were taken from the Protein Data Bank. These experimental conformations were then plotted on energy surfaces that were calculated with a hybrid of HF/6‐31G* and MM3(96) energies. Energy values corresponding to each crystallographic conformation were then pooled. Nearly 70% of the 210 structures had energies of 1 kcal mol−1 or less. A cumulative frequency analysis showed that most points fell on a curve that had an exponential decrease in the number of observed structures as the energy increased. This is analogous to a Boltzmann distribution but at higher temperature. This analysis showed that more than 90% of the linkages were not unusually distorted, and the distribution was similar to that found for small‐molecule crystals of carbohydrates. However, above 2 kcal mol−1, the observed points deviated from the curve. Most of these high‐energy observations were from linkages being broken by enzymatic attack, but others were not, and some scissile linkages were not unusually distorted. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 416–425, 2001*
Reactive scattering within a time‐dependent discrete variable representation
Authors: Billing G. D.
Published: September 2002

We have formulated a theory in which the quantum corrections to classical mechanics are easy to introduce. The method is based upon a time‐dependent discrete variable representation (DVR) of the wavefunction with grid points defined by the Hermite part of a basis set, the so‐called Gauss–Hermite basis set. The formulation introduces a set of grid points which follow the classical trajectory in space. With enough trajectories (DVR points), the method approaches the exact quantum formulation. With just a single grid point in a given degree of freedom, we have a classical mechanical description. © 2001 John Wiley & Sons, Inc. Int J Quant Chem, 2001
Quantum‐phase and information‐entropy dynamics of dimers interacting with a single‐mode coherent field: The difference between one‐ and two‐exciton models
Authors: Nakano M. , Yamaguchi K.
Published: September 2002

We develop a numerically exact approach to the quantum‐phase and information‐entropy dynamics of a molecular aggregate interacting with quantized fields. It is well known that a peculiar quantum nature, i.e., collapses and revivals, is observed in monomer and noninteracting aggregate models. In this article, we investigate the intermolecular interaction effects on the collapse‐revival behavior using several dimer models (composed of two‐state monomers with different intermolecular distances) interacting with a single‐mode coherent photon field. The intermolecular interaction is taken into account by using the dipole‐dipole interaction. Also, one‐ and two‐exciton dimer models are considered in order to elucidate the exciton contributions to collapse‐revival behavior. This quantum behavior is analyzed from the viewpoint of the dynamics of Pegg–Barnett photon‐phase and information‐entropy of dimers, which closely relate to the time evolution of quantum coherency between the ground and the excited dimer states and the degree of the entanglement between dimer and photon, respectively. It is found that the intermolecular interaction and the two‐exciton generation provide remarkable changes in the collapse‐revival behavior through their significant influence on the quantum‐phase dynamics and the photon‐dimer entanglement. From the dimer entropy dynamics, intermediate intermolecular interaction is found to cause the momentary decrease in the photon‐dimer correlation in the early time region. This feature leads to the enhancement of off‐diagonal density (quantum coherency) between two dimers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
A new approach to data reduction and evaluation in high‐resolution time‐of‐flight mass spectrometry using a time‐to‐digital convertor data‐recording system
Authors: Raznikov Valeri V. , Pikhtelev Alexander R. , Dodonov Alexander F. , Raznikova Marina O.
Published: September 2002

A new effective and robust approach to the detection of incompletely resolved peaks, and evaluation of their parameters in high‐resolution time‐of‐flight mass spectra for time‐to‐digital convertor (TDC) data acquisition mode, is described. The method is based on fast construction of a smoothed continuous curve that approximates the initial data (transformed to a constant relative width of time intervals for ion counting) with respect to precision of measurements. The first derivative of this curve is used for correction of skewness of the peak shape as far as possible. A contribution of the second derivative is subtracted from the smoothed curve for better resolution of partially resolved peaks. The comparison of local maxima of this resulting final curve with those for the initial smoothed curve allows reliable detection of the peaks and to test whether or not they are spoiled by overlapping. Ion counting performed by TDC gives an opportunity to estimate standard deviations of peak locations and their intensities. These values proved to be close to theoretically minimal standard deviations for these parameters for single fully resolved peaks. Thus, estimates of the main parameters of mass peaks by the described method are close to statistically efficient estimators for these parameters. Copyright © 2001 John Wiley & Sons, Ltd.
Characterisation of dissolved combined amino acids in marine waters
Authors: Sommerville Kay , Preston Tom
Published: September 2002

Dissolved combined amino acids (DCAA) are important constituents of the dissolved organic nitrogen (DON) pool in marine environments, although little is known about their sources, dynamics and sinks. The DCAA pool consists of various compounds including proteins and peptides, proteins linked to sugars and amino acids adsorbed to humic and fulvic acids, clays and other materials. The proportions of each of these components and the extent to which they are used by microplankton living within the photic zone are not known. An investigation was carried out, using 15N isotope dilution techniques, to determine the concentration and composition of dissolved amino acid pools in the marine environment. A near‐shore seawater sample was collected and split into fractions to determine the concentrations of dissolved free amino acids (DFAA), DCAA and a <3 kDa dissolved peptide fraction (DPEP; obtained by ultrafiltration). DCAA and DPEP fractions were hydrolysed to yield free amino acids and all samples were analysed by gas chromatography/mass spectrometry (GC/MS) as isobutyloxycarbonyl/tert‐butyldimethylsilyl derivatives. The DFAA was the smallest fraction representing ∼1% of total dissolved amino acids. The majority of DCAA was contained in the low molecular weight DPEP fraction (90%) and was probably as a result of release from phytoplankton and degradation by heterotrophic bacteria. Copyright © 2001 John Wiley & Sons, Ltd.
Diurnal fluxes and the isotopomer ratios of N2O in a temperate grassland following urine amendment
Authors: Yamulki S. , Toyoda S. , Yoshida N. , Veldkamp E. , Grant B. , Bol R.
Published: September 2002

There is an urgent need to provide an accurate, up‐to‐date estimate of N2O fluxes in order that national policies can be developed to reduce emissions of N2O from soils. There are only limited data on temporal and diurnal patterns of N2O fluxes to the atmosphere, mainly due to constraints in the measurement techniques. In this paper we present the first terrestrial source values of N2O isotopomers and have measured and quantified the temporal and diurnal variability in N2O fluxes following urine addition to a grassland system in the UK. The experiment was carried out over a 2‐week period on an artificially drained grassland system at the Institute of Grassland and Environmental Research (IGER), North Wyke, UK. Duplicate samples of urine, each of 2 L, were collected from dairy cows and applied to chambers (of area 0.16 m2). The N2O diurnal fluxes from urine and control (no urine) plots were measured by an automatic closed chamber technique. The isotopomers of N2O were obtained by analysing the gas samples collected during a peak emission phase. Soil and meteorological data were also collected. The results showed strong diurnal variations in N2O fluxes with minimum fluxes generally occurring between 7:00 and 14:00 hrs. The total cumulative flux of N2O for the whole experimental period was higher by a factor of >2 compared with estimates based on the daytime (between 10.00–16.00 hrs) measurements only. Therefore, measurements of N2O fluxes based on daily single exposure and expressed on a 24‐h basis could impose a considerable bias and inaccuracy to the emission estimates, depending on when it was taken. The measured site preference values (difference between the centre (δ15Nα) and the end (δ15Nβ) N atom of the N2O molecule) for soil‐emitted N2O measured during our study were always lower than the tropospheric value. This work confirms that the enhanced tropospheric N2O site preference value could be the result of the back injection from the stratosphere. The intramolecular isotope ratios of nitrogen (δ15N) and oxygen (δ18O) and the site preference of the emitted N2O indicated that there was a shift of processes during the measurement period. Copyright © 2001 John Wiley & Sons, Ltd.
Selective self‐ion/molecule reactions in both external and internal source ion trap mass spectrometers
Authors: Wu Hui‐Fen , Ho Ming‐Yi
Published: September 2002

Novel results on the selective self‐ion/molecule reactions (SSIMR) in both external and internal source ion trap mass spectrometers are demonstrated. Selective self‐ion/molecule reaction product ions were produced between the oxygenated and nitrogenated crown ethers. For the oxygenated crown ethers, self‐ion/molecule reactions lead to the formation of the protonated ions, adduct ions of fragments ([M + F]+) and [M + H3O]+, while the nitrogenated crown ethers produce [M + H]+, [M + CH]+ and [M + C2H3]+ ions. Copyright © 2001 John Wiley & Sons, Ltd.
New aspects in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry: a universal solvent‐free sample preparation
Authors: Trimpin S. , Rouhanipour A. , Az R. , Räder H. J. , Müllen K.
Published: September 2002

A method of solvent‐free sample preparation is shown to be of universal applicability for matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). Results obtained were compared with those of traditional solvent‐based sample preparation for MALDI‐MS in order to demonstrate their similarities with respect to accuracy, sensitivity and resolution for polymers such as polystyrene and poly(methyl methacrylate) in a mass range from 2 to 100 kDa. The results revealed that there is fundamentally no difference in the quality of the obtained mass spectra, and we conclude that the mechanism of desorption and ionization remains unchanged. However, the solvent‐free sample preparation turned out to have some advantages over the traditional method in certain cases: quick and easy applicability is shown for polyetherimide avoiding time‐consuming optimization procedures. In particular, industrial pigments that are insoluble in common solvents were characterized without interfering signals from fragments. The method even showed improvements with respect to reproducibility and mass discrimination effects in comparison to traditional sample preparation. Additionally, this contribution provides new insight regarding the analyte/matrix preorganization for the desorption step which now appears to be independent of crystallinity. Copyright © 2001 John Wiley & Sons, Ltd.