bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of integrins, tetraspanins, and ADAM proteins during the development of apoptotic bodies by spermatogenic cells
Authors: Kierszenbaum Abraham L. , Rosselot Carolina , Rivkin Eugene , Tres Laura L. 
Published: March 2006

AbstractWe have previously reported that Sertoli cell geometric changes induced by a Fas (CD95) agonist or by restricting Sertoli cell spreading can trigger spermatogenic cell detachment from Sertoli cell surfaces and initiate a programmed cell death sequence. Here, we have focused on ADAM proteins, tetraspanins CD9 and CD81, and the integrin β1 subunit, which is co‐expressed in testis with integrin α3 and integrin α6 subunits, to understand how these molecules may stabilize spermatogenic cell attachment to Sertoli cell surfaces. Like ADAM proteins, integrin β1, α3, and α6 subunits, and CD9 and CD81 transcripts are expressed in the fetal testis and throughout testicular maturation, as well as, in Sertoli‐spermatogenic cell co‐ cultures. Prespermatogonia (gonocytes) display CD9 and CD81 immunoreactive sites. Integrin α6 subunit transcripts have unusual developmental characteristics: fetal testis expresses the integrin α6B isoform exclusively. In contrast, the integrin α6B isoform co‐exists with the integrin α6A isoform in prepubertal testes and Sertoli‐spermatogenic cell co‐cultures. A blocking anti body targeting the extracellular domain (N‐terminal) of the integrin β1 subunit causes rapid contraction of Sertoli cells leading to the gradual detachment of associated spermatogenic cells. In contrast, predicted active site peptides targeting the disintegrin domain of ADAM 1, ADAM 2, ADAM 3 (cyritestin), ADAM 4, ADAM 5, ADAM 6, and ADAM 15 (metragidin) do not disturb significantly the attachment of spermatogenic cells to Sertoli cell surfaces. Spermatogenic cells dislodged from their attachment sites by the integrin β1 subunit blocking antibody display annexin V immunoreactivity, a sign of early apoptosis. Time‐lapse videomicroscopy demonstrates that the removal by apoptosis of a single member of a spermatogenic cell cohort inter‐connected by cytoplasmic bridges does not affect the remaining members of the cohort. During spermatogenic cell apoptosis, integrin β1, α3, and α6 subunits, and tetraspanins CD9 and C81 become displaced away from the developing apoptotic bodies. In contrast, the intermediate filament protein Sak57, a keratin 5 ortholog, concentrates in the developing apoptotic bodies. We propose that the redistribution of integrin–tetraspanin complexes during spermatogenic cell apoptosis may be evidence of a signaling cascade initiated by Sertoli cell geometric changes. As a result, Sertoli cell reduction in surface area may be a limiting factor of spermatogenic cell survival and in the developmental regulation of spermatogenic cell progenies in the intact seminiferous epithelium. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
The influence of the construction process on the deformation behaviour of diaphragm walls in soft clayey ground
Authors: Schäfer R. , Triantafyllidis Th. 
Published: March 2006

AbstractConventional numerical predictions of deep excavations normally neglect the construction process of the retaining structure and choose the earth pressure at rest as initial condition at the beginning of the simulation. The presented results of simulation and measurements during the construction process of the Taipei National Enterprise Center show, that such an assumption leads to an underestimation of the horizontal wall deflection, the surface ground settlements as well as the loading of the struts in case of normally to slightly over‐consolidated clayey soil deposits. The stepwise installation process of the individual diaphragm wall panels results in a substantial modification of the lateral effective stresses in the adjacent ground. Especially the pouring process of the panel and the fresh concrete pressure causes a partial mobilization of the passive earth pressure and a distinct stress level increase in the upper half of the wall. As a consequence of the increased stresses prior to the pit excavation, up to 15% greater ground and wall movements are predicted. Moreover, the increased stress level due to the installation process of the diaphragm wall leads to substantial higher strut loadings during the excavation of the pit. Copyright © 2006 John Wiley & Sons, Ltd.
A variable time transformation method for mixed‐integer optimal control problems
Authors: Gerdts Matthias 
Published: March 2006

AbstractThe article discusses a variable time transformation method for the approximate solution of mixed‐integer non‐linear optimal control problems (MIOCP). Such optimal control problems enclose real‐valued and discrete‐valued controls. The method transforms MIOCP using a discretization into an optimal control problem with only real‐valued controls. The latter can be solved efficiently by direct shooting methods. Numerical results are obtained for a problem from automobile test‐driving that involves a discrete‐valued control for the gear shift of the car. The results are compared to those obtained by Branch&Bound and show a drastic reduction of computation time. This very good performance makes the suggested method applicable even for many discretization points. Copyright © 2006 John Wiley & Sons, Ltd.
Is proton cationization promoted by polyatomic primary ion bombardment during time‐of‐flight secondary ion mass spectrometry analysis of frozen aqueous solutions?
Authors: Conlan Xavier A. , Lockyer Nicholas P. , Vickerman John C. 
Published: March 2006

AbstractIon bombardment of pure water ice by Au+ monoatomic and Au and C polyatomic projectiles results in the emission of two series of water cluster ions—(H2O) and (H2O)nH+—with n ranging from 1 to >40. The cluster ion yields are very significantly higher under polyatomic ion bombardment than when using an Au+ primary ion. The yield of the protonated water species (H2O)nH+ is found to be enhanced by increasing ion fluence. C bombardment results in a very dramatic increase in the (H2O)nH+ yield and decrease in the yield of (H2O). Au also significantly increased the yield of protonated species relative to the non‐protonated but to a lesser extent than C. Bombardment by Au+ also increased the yield of protonated species but to a very much smaller extent. The hypothesis that the protonated species may enhance the yield of [M+H]+ from solute molecules in solution has been investigated using two amino acids, alanine and arginine, and a nucleic base, adenine. The data suggest that the protons produced by the sputtering of water ice are depleted in the presence of these solutes and concurrently the yields of solute‐related [M+H]+ and immonium secondary ions are greatly enhanced. These yield enhancements are analysed in the light of other possible contributors such as increased rates of sputtering under polyatomic beams and increased secondary ion yields as a consequence of solute dispersion. It is concluded that enhanced proton attachment is occurring in polyatomic sputtered frozen aqueous solutions. Copyright © 2006 John Wiley & Sons, Ltd.
Chemometric evaluation of time‐of‐flight secondary ion mass spectrometry data of minerals in the frame of future in situ analyses of cometary material by COSIMA onboard ROSETTA
Authors: Engrand Cecile , Kissel Jochen , Krueger Franz R. , Martin Philippe , Silén Johan , Thirkell Laurent , Thomas Roger , Varmuza Kurt 
Published: March 2006

AbstractChemometric data evaluation methods for time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) have been tested for the characterization and classification of minerals. Potential applications of these methods include the expected data from cometary material to be measured by the COSIMA instrument onboard the ESA mission ROSETTA in the year 2014. Samples of the minerals serpentine, enstatite, olivine, and talc have been used as proxies for minerals existing in extraterrestrial matter. High mass resolution TOF‐SIMS data allow the selection of peaks from inorganic ions relevant for minerals. Multivariate cluster analysis of peak intensity data by principal components analysis and the new method CORICO showed a good separation of the mineral classes. Classification by k nearest‐neighbor classification (KNN) or binary decision trees (CART method) results in more than 90% correct class assignments in a leave‐one‐out cross validation. Copyright © 2006 John Wiley & Sons, Ltd.
Improvement of 2,4‐dinitrophenylhydrazine derivatization method for carbon isotope analysis of atmospheric acetone
Authors: Wen Sheng , Yu Yingxin , Guo Songjun , Feng Yanli , Sheng Guoying , Wang Xinming , Bi Xinhui , Fu Jiamo , Jia Wanglu 
Published: March 2006

AbstractThrough simulation experiments of atmospheric sampling, a method via 2,4‐dinitrophenylhydrazine (DNPH) derivatization was developed to measure the carbon isotopic composition of atmospheric acetone. Using acetone and a DNPH reagent of known carbon isotopic compositions, the simulation experiments were performed to show that no carbon isotope fractionation occurred during the processes: the differences between the predicted and measured data of acetone‐DNPH derivatives were all less than 0.5‰. The results permitted the calculation of the carbon isotopic compositions of atmospheric acetone using a mass balance equation. In this method, the atmospheric acetone was collected by a DNPH‐coated silica cartridge, washed out as acetone‐DNPH derivatives, and then analyzed by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Using this method, the first available δ13C data of atmospheric acetone are presented. Copyright © 2006 John Wiley & Sons, Ltd.
Water extraction times for plant and soil materials used in stable isotope analysis
Authors: West Adam G. , Patrickson Shela J. , Ehleringer James R. 
Published: March 2006

AbstractStable isotopic analysis of water for many ecological applications commonly requires extractions of water from dozens to hundreds of plant and soil samples. With recent advances in mass spectrometry, water extraction, rather than the isotopic analysis itself, is the bottleneck in sample processing. Using cryogenic vacuum distillation, we have created extraction timing curves to determine how much time (Tmin) is required to extract an unfractionated water sample. Our results indicated that Tmin values are 60 to 75 min for stems, 40 min for clay soils, 30 min for sandy soils and 20 to 30 min for leaves. While the extraction times reported here may allow for some reductions relative to times reported in the literature, the extraction process will continue to be a rate‐limiting step in plant water analyses. Ultimately, technological advances eliminating the need for extraction are required to greatly increase throughput rates in water isotope analysis for ecological research. Copyright © 2006 John Wiley & Sons, Ltd.
Quantification of benzo[a]pyrene diol epoxide DNA‐adducts by stable isotope dilution liquid chromatography/tandem mass spectrometry
Authors: Ruan Qian , Kim Hye‐Young H. , Jiang Hao , Penning Trevor M. , Harvey Ronald G. , Blair Ian A. 
Published: March 2006

AbstractPolycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants found in car exhausts, charbroiled food, and tobacco smoke. Three pathways for the metabolic activation of B[a]P to ultimate carcinogens have been proposed. The most widely accepted pathway involves cytochrome‐P450 (CYP) 1A1‐ and/or 1B1‐mediated formation of B[a]P‐7,8‐oxide, which undergoes epoxide hydrolase‐mediated metabolism to the proximate carcinogen B[a]P‐7,8‐dihydro‐7,8‐diol. Further CYP1A1‐ and/or CYP1B1‐mediated activation of the dihydrodiol results in the formation of 7,8‐dihydroxy‐9,10‐epoxy‐7,8,9,10‐tetrahydrobenzo[a]pyrene (B[a]PDE), the ultimate carcinogen. In previous studies, it was demonstrated that (+)‐anti‐B[a]PDE was the most potent tumorigen of the CYP‐derived B[a]PDE diastereomers. We have developed a stable isotope dilution, liquid chromatography multiple reaction monitoring/mass spectrometry (LC‐MRM/MS) assay for all eight (±)‐anti‐B[a]PDE‐derived dGuo and dAdo DNA‐adducts. The LC‐MRM/MS assay was rigorously validated and used to show that (+)‐anti‐trans‐B[a]PDE‐dGuo was the major adduct formed when naked DNA and human bronchoalveolar adenocarcinoma H358 cells were treated with (±)‐anti‐B[a]PDE. The preference for DNA‐adducts derived from (+)‐anti‐B[a]PDE was even more apparent in cellular DNA. Thus, the increased potency of (+)‐anti‐B[a]PDE as a tumorigen is most likely due its ability to preferentially form DNA‐adducts when compared with (−)‐anti‐B[a]PDE. Also, the adduct profile suggests that this occurs by binding of (+)‐anti‐B[a]PDE to DNA in a manner that facilitates covalent binding to dGuo rather than dAdo residues. Copyright © 2006 John Wiley & Sons, Ltd.
Ultra‐performance liquid chromatography coupled to linear ion trap mass spectrometry for the identification of drug metabolites in biological samples
Authors: Dear G. J. , James A. D. , Sarda S. 
Published: March 2006

AbstractThe coupling of ultra‐performance liquid chromatography, operating at elevated pressures, to a linear ion trap mass spectrometer provides a high‐performance system suitable for drug metabolite characterisation. This system demonstrates improved chromatographic efficiency and sensitivity and at the same time provides diagnostic MSndata often critical for metabolite structural assignment. The linear ion trap was capable of dealing with the high chromatographic efficiencies and hence narrow peak widths associated with 1.7 µm particle‐packed column separations. Polarity switching and data‐dependent MSndata were generated with ease, and applied to the identification of metabolites found in human plasma. Copyright © 2006 John Wiley & Sons, Ltd.
Expert models and modeling processes associated with a computer‐modeling tool
Authors: Zhang BaoHui , Liu Xiufeng , Krajcik Joseph S. 
Published: March 2006

AbstractHolding the premise that the development of expertise is a continuous process, this study concerns expert models and modeling processes associated with a modeling tool called Model‐It. Five advanced Ph.D. students in environmental engineering and public health used Model‐It to create and test models of water quality. Using “think aloud” technique and video recording, we captured their computer screen modeling activities and thinking processes. We also interviewed them the day following their modeling sessions to further probe the rationale of their modeling practices. We analyzed both the audio–video transcripts and the experts' models. We found the experts' modeling processes followed the linear sequence built in the modeling program with few instances of moving back and forth. They specified their goals up front and spent a long time thinking through an entire model before acting. They specified relationships with accurate and convincing evidence. Factors (i.e., variables) in expert models were clustered, and represented by specialized technical terms. Based on the above findings, we made suggestions for improving model‐based science teaching and learning using Model‐It. © 2006 Wiley Periodicals, Inc. Sci Ed 90:579–2604, 2006
Dimensions that shape teacher–scientist collaborations for teacher enhancement
Authors: Drayton Brian , Falk Joni 
Published: March 2006

AbstractPartnerships of teachers with scientists are thought to be important for many aspects of science education reform, but it is not always clear how to make such partnerships productive. Between 1994 and 1997, high school teachers were partnered with scientists, to design yearlong ecological research projects in which the teachers were learning for their own sake, rather than to create new curriculum. In these partnerships the relationships with the scientists took many forms. We found that negotiations around five dimensions seemed particularly important: (1) Whose question was being investigated? (2) Was the focus primarily on data collection or data analysis? (3) Was the research based on the ecologist's area of expertise, or the teachers' interest? (4) Was the focus primarily on the teachers' learning on their students' classroom learning? (5) Was the research intended for an external audience, or primarily for the teachers' own benefit? Three case studies are presented, showing how these dimensions shaped the negotiations of more successful and less successful collaborations. Implications for inquiry‐based pedagogy, and cultural issues arising in scientist‐teacher collaborations, are discussed. © 2006 Wiley Periodicals, Inc. Sci Ed, 90:734–761, 2006
The Berry-Esseen bound for character ratios
Authors: Shao Qi-Man , Su Zhong-Gen 
Published: March 2006

Letλ\lambdabe a partition ofnnchosen from the Plancherel measure of the symmetric groupSnS_n, letχλ(12)\chi ^\lambda (12)be the irreducible character of the symmetric group parameterized byλ\lambdaevaluated on the transposition(12)(12), and letdim⁡(λ)\dim (\lambda )be the dimension of the irreducible representation parameterized byλ\lambda. Fulman recently obtained the convergence rate ofO(n−s)O(n^{-s})for any0>s>120> s>\frac 12in the central limit theorem for character ratios(n−1)2χλ(12)dim⁡(λ){(n-1) \over \sqrt {2} } \, {\chi ^\lambda (12) \over \dim (\lambda )}by developing a connection between martingale and character ratios, and he conjectures that the correct speed isO(n−1/2)O(n^{-1/2}). In this paper we confirm the conjecture via a refinement of Stein’s method for exchangeable pairs.
On a conjecture about MRA Riesz wavelet bases
Authors: Han Bin 
Published: March 2006

Let

ϕ
\phi

be a compactly supported refinable function in

L
2

(

R

)

L_2(\mathbb {R})

such that the shifts of

ϕ
\phi

are stable and

ϕ
^

(
2
ξ
)
=

a
^

(
ξ
)

ϕ
^

(
ξ
)

\hat \phi (2\xi )=\hat a(\xi )\hat \phi (\xi )

for a

2
π

2\pi

-periodic trigonometric polynomial

a
^

\hat a

. A wavelet function

ψ
\psi

can be derived from

ϕ
\phi

by

ψ
^

(
2
ξ
)
:=

e

−
i
ξ

a
^

(
ξ
+
π
)

¯

ϕ
^

(
ξ
)

\hat \psi (2\xi ):=e^{-i\xi }\overline {\hat a(\xi +\pi )} \hat \phi (\xi )

. If

ϕ
\phi

is an orthogonal refinable function, then it is well known that

ψ
\psi

generates an orthonormal wavelet basis in

L
2

(

R

)

L_2(\mathbb {R})

. Recently, it has been shown in the literature that if

ϕ
\phi

is a

B
B

-spline or pseudo-spline refinable function, then

ψ
\psi

always generates a Riesz wavelet basis in

L
2

(

R

)

L_2(\mathbb {R})

. It was an open problem whether

ψ
\psi

can always generate a Riesz wavelet basis in

L
2

(

R

)

L_2(\mathbb {R})

for any compactly supported refinable function in

L
2

(

R

)

L_2(\mathbb {R})

with stable shifts. In this paper, we settle this problem by proving that for a family of arbitrarily smooth refinable functions with stable shifts, the derived wavelet function

ψ
\psi

does not generate a Riesz wavelet basis in

L
2

(

R

)

L_2(\mathbb {R})

. Our proof is based on some necessary and sufficient conditions on the

2
π

2\pi

-periodic functions

a
^

\hat a

and

b
^

\hat b

in

C

∞

(

R

)

C^{\infty }(\mathbb {R})

such that the wavelet function

ψ
\psi

, defined by

ψ
^

(
2
ξ
)
:=

b
^

(
ξ
)

ϕ
^

(
ξ
)

\hat \psi (2\xi ):=\hat b(\xi )\hat \phi (\xi )

, generates a Riesz wavelet basis in

L
2

(

R

)

L_2(\mathbb {R})

.
On the local structure of rank-one convex hulls
Authors: Székelyhidi László 
Published: March 2006

In this note we prove that ifKKis a compact set ofm×nm\times nmatrices containing an isolated pointXXwith no rank-one connection into the convex hull ofK∖{X}K\setminus \{X\}, then the rank-one convex hull separates as\[Krc=(K∖{X})rc∪{X}.K^{rc}=\bigl (K\setminus \{X\}\bigr )^{rc}\cup \{X\}.\]This is an extension of a result of P. Pedregal, which holds for2×22\times 2matrices.
On the invariant translation approximation property for discrete groups
Authors: Zacharias Joachim 
Published: March 2006

Recently J. Roe considered the question of whether for a discrete group the reduced group

C
∗

C^*

-algebra

C
r
∗

(
Γ
)

C_r^*(\Gamma )

is the fixed point algebra of

{
Ad
(

ρ
t

)
∣
t
∈
Γ
}

\{\text {Ad}(\rho _t) \mid t \in \Gamma \}

acting on the uniform Roe algebra

U

C
r
∗

(
Γ
)

UC_r^*(\Gamma )

.

Γ
\Gamma

is said to have the invariant translation approximation property in this case. We consider a slight generalization of this property which, for exact

Γ
\Gamma

, is equivalent to the operator space approximation property of

C
r
∗

(
Γ
)

C_r^*(\Gamma )

. We also give a new characterization of exactness and a short proof of the equivalence of exactness of

Γ
\Gamma

and exactness of

C
r
∗

(
Γ
)

C_r^*(\Gamma )

for discrete groups.
A hyperfinite inequality for free entropy dimension
Authors: Jung Kenley 
Published: March 2006

If

X
,
Y

X, Y

, and

Z
Z

are finite sets of selfadjoint elements in a tracial von Neumann algebra and

X
X

generates a hyperfinite von Neumann algebra, then

δ
0

(
X
∪
Y
∪
Z
)
≤

δ
0

(
X
∪
Y
)
+

δ
0

(
X
∪
Z
)
−

δ
0

(
X
)
.

\delta _0(X \cup Y \cup Z) \leq \delta _0(X \cup Y) + \delta _0(X \cup Z)- \delta _0(X).
CASPAR: a hierarchical bayesian approach to predict survival times in cancer from gene expression data
Authors: Kaderali Lars , Zander Thomas , Faigle Ulrich , Wolf Jürgen , Schultze Joachim L. , Schrader Rainer 
Published: March 2006

AbstractMotivation: DNA microarrays allow the simultaneous measurement of thousands of gene expression levels in any given patient sample. Gene expression data have been shown to correlate with survival in several cancers, however, analysis of the data is difficult, since typically at most a few hundred patients are available, resulting in severely underdetermined regression or classification models.Several approaches exist to classify patients in different risk classes, however, relatively little has been done with respect to the prediction of actual survival times. We introduce CASPAR, a novel method to predict true survival times for the individual patient based on microarray measurements. CASPAR is based on a multivariate Cox regression model that is embedded in a Bayesian framework. A hierarchical prior distribution on the regression parameters is specifically designed to deal with high dimensionality (large number of genes) and low sample size settings, that are typical for microarray measurements. This enables CASPAR to automatically select small, most informative subsets of genes for prediction.Results: Validity of the method is demonstrated on two publicly available datasets on diffuse large B-cell lymphoma (DLBCL) and on adenocarcinoma of the lung. The method successfully identifies long and short survivors, with high sensitivity and specificity. We compare our method with two alternative methods from the literature, demonstrating superior results of our approach. In addition, we show that CASPAR can further refine predictions made using clinical scoring systems such as the International Prognostic Index (IPI) for DLBCL and clinical staging for lung cancer, thus providing an additional tool for the clinician. An analysis of the genes identified confirms previously published results, and furthermore, new candidate genes correlated with survival are identified.Availability: The software is available upon request from the authors.Contact: kaderali@zpr.uni-koeln.deSupplementary information: