bluuebunny/crossref_metadata_2025 huggingface dataset:
𝑛-clusters for 1<𝑛<7
Authors: Noll Landon Curt , Bell David I.
Published: June 2010

An n-cluster is a set of n lattice points in

R

2

{{\mathbf {R}}^2}

with no 3 points collinear, no 4 points concyclic, and where all mutual distances are nonzero integers. The initial discoveries of n-clusters for

1
>
n
>
7

1 > n > 7

are reported. A progress report on small 6-clusters and the search for a 7-cluster is described. A question on the impact of the lattice point restriction is raised, and the definition of n-cluster is generalized to

R

m

{{\mathbf {R}}^m}

.
The serial test for congruential pseudorandom numbers generated by inversions
Authors: Niederreiter Harald
Published: June 2010

Two types of congruential pseudorandom number generators based on inversions were introduced recently. We analyze the statistical independence properties of these pseudorandom numbers by means of the serial test. The results show that these pseudorandom numbers perform satisfactorily under the serial test. The methods of proof rely heavily on bounds for character sums such as the Weil-Stepanov bound for character sums over finite fields.
On the lcm of the differences of eight primes
Authors: Morain François
Published: June 2010

Following C. A. Spiro, who has found eight primes for which
\[

lcm
⁡

(

p
j

−

p
i

)

1
≤
i
>
j
≤
8

=
5040
,

\operatorname {lcm}{({p_j} - {p_i})_{1 \leq i > j \leq 8}} = 5040,

\]
we show that for every set of eight odd primes

{

q
1

,
…
,

q
8

}

\{ {q_1}, \ldots ,{q_8}\}

, one has

5040

|

lcm
⁡
(

q
j

−

q
i

)

5040|\operatorname {lcm}({q_j} - {q_i})

. Moreover,

lcm
⁡
(

q
j

−

q
i

)
=
5040

\operatorname {lcm}({q_j} - {q_i}) = 5040

infinitely often, under the assumption of the 8-tuple conjecture.
A fast algorithm for rational interpolation via orthogonal polynomials
Authors: Eğecioğlu Ömer , Koç Çetin K.
Published: June 2010

A new algorithm for rational interpolation is proposed. Given the data set, the algorithm generates a set of orthogonal polynomials by the classical three-term recurrence relation and then uses Newton interpolation to find the numerator and the denominator polynomials of the rational interpolating function. The number of arithmetic operations of the algorithm to find a particular rational interpolant is

O
(

N
2

)

O({N^2})

, where

N
+
1

N + 1

is the number of data points. A variant of this algorithm that avoids Newton interpolation can be used to construct all rational interpolants using only

O
(

N
2

)

O({N^2})

arithmetic operations.
Computing greatest common divisors and factorizations in quadratic number fields
Authors: Kaltofen Erich , Rolletschek Heinrich
Published: June 2010

In a quadratic number field

Q

(

D

)

{\mathbf {Q}}(\sqrt D )

, D a squarefree integer, with class number 1, any algebraic integer can be decomposed uniquely into primes, but for only 21 domains Euclidean algorithms are known. It was shown by Cohn [5] that for

D
≤
−
19

D \leq - 19

even remainder sequences with possibly nondecreasing norms cannot determine the GCD of arbitrary inputs. We extend this result by showing that there does not even exist an input in these domains for which the GCD computation becomes possible by allowing nondecreasing norms or remainders whose norms are not as small as possible. We then provide two algorithms for computing the GCD of algebraic integers in quadratic number fields

Q

(

D

)

{\mathbf {Q}}(\sqrt D )

. The first applies only to complex quadratic number fields with class number 1, and is based on a short vector construction in a lattice. Its complexity is

O
(

S
3

)

O({S^3})

, where S is the number of bits needed to encode the input. The second algorithm allows us to compute GCD’s of algebraic integers in arbitrary number fields (ideal GCD’s if the class number is

>
1

> 1

). It requires only

O
(

S
2

)

O({S^2})

binary steps for fixed D, but works poorly if D is large. Finally, we prove that in any domain, the computation of the prime factorization of an algebraic integer can be reduced in polynomial time to the problem of factoring its norm into rational primes. Our reduction is based on a constructive version of a theorem by A. Thue.
New bound for the first case of Fermat’s last theorem
Authors: Tanner Jonathan W. , Wagstaff Samuel S.
Published: June 2010

We present an improvement to Gunderson’s function, which gives a lower bound for the exponent in a possible counterexample to the first case of Fermat’s "Last Theorem," assuming that the generalized Wieferich criterion is valid for the first n prime bases. The new function increases beyond

n
=
29

n = 29

, unlike Gunderson’s, and it increases more swiftly. Using the recent extension of the Wieferich criterion to

n
=
24

n = 24

by Granville and Monagan, the first case of Fermat’s "Last Theorem" is proved for all prime exponents below 156, 442, 236, 847, 241, 729.
Convergence of the nonconforming Wilson element for a class of nonlinear parabolic problems
Authors: Chou S. H. , Li Q.
Published: June 2010

This paper deals with the convergence properties of the nonconforming quadrilateral Wilson element for a class of nonlinear parabolic problems in two space dimensions. Optimal

H
1

{H^1}

and

L
2

{L_2}

error estimates for the continuous time Galerkin approximations are derived. It is also shown for rectangular meshes that the gradient of the Wilson element solution possesses superconvergence, and that the

L
∞

{L_\infty }

error on the gradient is of order

h
log
⁡
(
1

/

h
)

h\log (1/h)

.
Chebyshev approximations for the natural logarithm of the Gamma function
Authors: Cody W. J. , Hillstrom K. E.
Published: June 2010

Rational Chebyshev approximations are given for the natural logarithm of the real gamma function for arguments in the intervals

[
0.5
,
1.5
]

[0.5,1.5]

,

[
1.5
,
4.0
]

[1.5,4.0]

and

[
4.0
,
12.0
]

[4.0,12.0]

. Maximal relative errors range down to

1
×

10

−
17

1 \times {10^{ - 17}}

.
Molecular Characterization of EG-VEGF-mediated Angiogenesis: Differential Effects on Microvascular and Macrovascular Endothelial Cells
Authors: Brouillet Sophie , Hoffmann Pascale , Benharouga Mohamed , Salomon Aude , Schaal Jean-Patrick , Feige Jean-Jacques , Alfaidy Nadia
Published: June 2010

Endocrine gland derived vascular endothelial growth factor (EG-VEGF) also called prokineticin (PK1), has been identified and linked to several biological processes including angiogenesis. EG-VEGF is abundantly expressed in the highest vascularized organ, the human placenta. Here we characterized its angiogenic effect using different experimental procedures. Immunohistochemistry was used to localize EG-VEGF receptors (PROKR1 and PROKR2) in placental and umbilical cord tissue. Primary microvascular placental endothelial cell (HPEC) and umbilical vein-derived macrovascular EC (HUVEC) were used to assess its effects on proliferation, migration, cell survival, pseudovascular organization, spheroid sprouting, permeability and paracellular transport. siRNA and neutralizing antibody strategies were used to differentiate PROKR1- from PROKR2-mediated effects. Our results show that 1) HPEC and HUVEC express both types of receptors 2) EG-VEGF stimulates HPEC's proliferation, migration and survival, but increases only survival in HUVECs. and 3) EG-VEGF was more potent than VEGF in stimulating HPEC sprout formation, pseudovascular organization, and it significantly increases HPEC permeability and paracellular transport. More importantly, we demonstrated that PROKR1 mediates EG-VEGF angiogenic effects, whereas PROKR2 mediates cellular permeability. Altogether, these data characterized angiogenic processes mediated by EG-VEGF, depicted a new angiogenic factor in the placenta, and suggest a novel view of the regulation of angiogenesis in placental pathologies.
The initial peopling of the Americas: A growing number of founding mitochondrial genomes from Beringia
Authors: Perego Ugo A. , Angerhofer Norman , Pala Maria , Olivieri Anna , Lancioni Hovirag , Kashani Baharak Hooshiar , Carossa Valeria , Ekins Jayne E. , Gómez-Carballa Alberto , Huber Gabriela , Zimmermann Bettina , Corach Daniel , Babudri Nora , Panara Fausto , Myres Natalie M. , Parson Walther , Semino Ornella , Salas Antonio , Woodward Scott R. , Achilli Alessandro , Torroni Antonio
Published: June 2010

Pan-American mitochondrial DNA (mtDNA) haplogroup C1 has been recently subdivided into three branches, two of which (C1b and C1c) are characterized by ages and geographical distributions that are indicative of an early arrival from Beringia with Paleo-Indians. In contrast, the estimated ages of C1d—the third subset of C1—looked too young to fit the above scenario. To define the origin of this enigmatic C1 branch, we completely sequenced 63 C1d mitochondrial genomes from a wide range of geographically diverse, mixed, and indigenous American populations. The revised phylogeny not only brings the age of C1d within the range of that of its two sister clades, but reveals that there were two C1d founder genomes for Paleo-Indians. Thus, the recognized maternal founding lineages of Native Americans are at least 15, indicating that the overall number of Beringian or Asian founder mitochondrial genomes will probably increase extensively when all Native American haplogroups reach the same level of phylogenetic and genomic resolution as obtained here for C1d.
Maternal‐effect gene Ces5/Ooep/Moep19/Floped is essential for oocyte cytoplasmic lattice formation and embryonic development at the maternal‐zygotic stage transition
Authors: Tashiro Fumi , Kanai‐Azuma Masami , Miyazaki Satsuki , Kato Masahiro , Tanaka Tomofumi , Toyoda Shuichi , Yamato Eiji , Kawakami Hayato , Miyazaki Tatsushi , Miyazaki Jun‐Ichi
Published: June 2010

In a search for genes specifically expressed in mouse embryonic stem cells, we identified one we called Ces5. We found that it corresponded to the Ooep gene, which was recently reported to be expressed specifically in oocytes. Mouse Ces5/Ooep, also called Moep19 or Floped, encoded a 164‐amino acid protein, which was detected in the cytoplasm of developing and mature oocytes and in embryos throughout the preimplantation period. To examine its function, we carried out targeted disruption of this gene. The Ces5/Ooep‐null mice were grossly normal, but the females were infertile. Although the ovaries and ovulation appeared normal, the embryos from Ces5/Ooep‐null females mated with wild‐type males showed developmental arrest at the two‐ or four‐cell stage. In addition, their first cleavage was considerably delayed and often asymmetrical. Thus, Ces5/Ooep is a maternal‐effect gene. By electron microscopy, we found that the eggs from Ces5/Ooep‐null females lacked oocyte cytoplasmic lattices (CPLs), which have long been predicted to function as a storage form for components that are maternally contributed to the early embryo. Further analysis showed that CES5/OOEP was directly associated with the CPLs. These results indicate that CES5/OOEP is an essential component of the CPLs and is required for embryonic development at the maternal‐zygotic stage transition.
First 20 years with recombinant FVIIa (NovoSeven)
Authors: HEDNER U. , LEE C. A.
Published: June 2010

Summary.  This review describes the background for the development of recombinant FVIIa (rFVIIa; NovoSeven) for use in haemophilic patients with inhibitors. The first proof of principle for using pharmacological doses of FVIIa as a haemostatic agent was obtained by producing small amounts of pure plasma‐derived FVIIa, which showed encouraging effect in two patients with haemophilia A and inhibitors. To make pure FVIIa available for use in a larger number of patients, rFVIIa was produced that was approved for use in patients with inhibitors against coagulation factors (congenital haemophilia and acquired haemophilia) in 1996 (EU), 1999 (USA) and 2000 (Japan). The efficacy rate in severe bleedings and in major surgery including major orthopaedic surgery has been found to be around 90% in controlled studies, and no serious safety concerns have been demonstrated. The availability of rFVIIa has facilitated the performance of elective major surgery in haemophilia patients with inhibitors. Further steps along the vision of providing a treatment for inhibitor patients similar to non‐inhibitor patients have been the efficacy of rFVIIa in home‐treatment and recently the encouraging experience in prophylaxis. The concept of using pharmacological doses of rFVIIa as a haemostatic agent is a new one, which has caused difficulties in finding the correct dose. A step forward has been the demonstration that similar efficacy can be achieved after one single dose of 270 μg kg−1 instead of three injections of a dose of 90 μg kg−1. The higher clearance rate in children suggests that higher doses may be beneficial in children. The availability of rFVIIa has made advances in the understanding of coagulation processes possible. In a cell‐based in vitro model, it has been shown that rFVIIa binds to preactivated platelets if present in concentrations of 30 nm or higher. By doing so, it activates FX into FXa and enhances the thrombin generation on the activated platelet surface in the absence of FVIII/FIX. Through the increased thrombin generation, a firm, well‐structured fibrin haemostatic plug, which is resistant to premature lysis, is formed. By exploiting this mechanism of action, rFVIIa may also be effective in situations other than haemophilia, characterized by an impaired thrombin generation.
Electron back‐scattering diffraction (EBSD) measurements of antigorite lattice‐preferred orientations (LPO)
Authors: VAN DE MOORTÈLE B. , BEZACIER L. , TRULLENQUE G. , REYNARD B.
Published: June 2010

Lattice preferred orientations of serpentines induce a strong anisotropy of various properties in serpentine bearing‐rocks. Lattice preferred orientations had so far been obtained only by X‐ray diffraction techniques. We have applied electron back‐scattering diffraction to the measurement of the lattice preferred orientations of antigorite in a naturally deformed high‐pressure serpentinite. This technique is very sensitive to sample preparation that can lead to surface amorphization in the case of serpentine. A polishing procedure is described that avoids amorphization and allows accurate electron back‐scattering diffraction measurements with optimized experimental conditions in a variable pressure scanning electron microscope. Results indicate that deformation leads to lattice preferred orientations characterized by extremely strong c‐axis clustering perpendicular to the foliation, as expected for a layered silicate. In the foliation plane, a significant clustering of the a‐axis is observed and tentatively attributed to intracrystalline deformation mechanisms. These data suggest that antigorite deforms mostly by gliding along the basal plane of the layered phyllosilicate structure, but that gliding may occur along directions favouring a‐axis alignment. Electron back‐scattering diffraction appears to be a reliable method for determining phyllosilicate lattice preferred orientations in deformed rocks, with potential applications for determining anisotropy of properties like seismic velocities or thermal and electrical conductivities.
Comparative study of the retinal vessel anatomy of rhesus monkeys and humans
Authors: Kong Xiangmei , Wang Kaidi , Sun Xinghuai , Witt Rachel E
Published: June 2010

Abstract

Objectives:  This study aims to compare retinal vessel anatomy of normal rhesus monkeys and humans and to provide a basis from a structural perspective for the use of rhesus monkey as an experimental model in future studies of retinal vessels.

Methods:  The retinas of six normal rhesus monkey eyes and eight human eyecups following corneal transplantation were obtained and stained using adenosine diphosphatase methods. The distributions, orders, layers of the retinal vessels and the perifoveal vascular ring were compared.

Results:  With adenosine diphosphatase staining, distinct retinal vessels were fully discernable from the first order surrounding the optic disc to the fifth order. There were no statistically significant differences between rhesus monkeys and humans in the percentages of vessels surrounding the optic disc at the equator and the peripheral region. Vascular networks in both species were arranged in several layers around the optic disc, two anastomotic layers at the equator and one sparse layer peripherally. Capillaries at the macular area were quite dense and an intact perifoveal vascular ring was observed. No differences were observed between rhesus monkeys and humans in the percentage area of the vessels and the area, perimeter and diameter of the perifoveal vascular ring.

Conclusions:  The distributions, orders, layers and the perifoveal vascular ring of the retinal vessels of rhesus monkey are quite similar to those of humans. The data suggest that from an anatomical perspective, the rhesus monkey is a good animal model for the study of human retinal vessels, particularly the macular capillaries.
Air pollution impedes plant‐to‐plant communication by volatiles
Authors: Blande James D. , Holopainen Jarmo K. , Li Tao
Published: June 2010

Ecology Letters (2010) 13: 1172–1181

Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore‐induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between‐plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone‐rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore‐induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80‐ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus.
Planning changes to health library services on the basis of impact assessment
Authors: Urquhart Christine , Thomas Rhian , Ovens Jason , Lucking Wendy , Villa Jane
Published: June 2010

Background:  Various methods of impact assessment for health library services exist, including a toolkit developed for the UK. The Knowledge, Resource and Information service (KRIS) for health promotion, health service commissioning and public health (Bristol area, UK) commissioned an independent team at Aberystwyth University to provide an impact assessment and evaluation of their services and to provide evidence for future planning.

Objective:  The review aimed to provide an action plan for KRIS through assessing the impact of the current service, extent of satisfaction with existing services and views on desirable improvements.

Methods:  Existing impact toolkit guidance was used, with an adapted impact questionnaire, which was distributed by the KRIS staff to 244 users (response rate 62.3%) in early 2009. The independent team analysed the questionnaire data and presented the findings.

Results:  Users valued the service (93% considered that relevant information was obtained). The most frequent impacts on work were advice to patients, clients or carers, and advice to colleagues. Literature searching and current awareness services saved staff time. Many users were seeking health promotion materials.

Conclusion:  The adapted questionnaire worked well in demonstrating the service impacts achieved by KRIS, as well as indicating desirable improvements in service delivery.
Celebrating the role of health information
Authors: Grant Maria J.
Published: June 2010

This inaugural virtual issue of the Health Information and Libraries Journal (HILJ) celebrates the contribution of health information in informing health and social care library and information provision. It has been drawn together to reflect the 2010 biennial Health Libraries Group conference theme of Keeping Information Centre Stage Amid Changing Scenery and includes a series of eleven key papers published in the journal over the last two years. This virtual issue mirrors the usual format of a journal issue with a review article, original articles and regular features on Learning and Teaching in Action, Using Evidence in Practice and International Perspectives and Initiatives. All papers included in this virtual issue of Health Information and Libraries Journal are available free online.
Operations research/management science contributions to peace studies
Authors: Bartolucci Valentina , Gallo Giorgio
Published: June 2010

The discourse on ethics in operations research/management science (OR/MS) has many aspects. Among them there is the ethical responsibility the OR/MS community faces in a world in which the widespread presence of structural violence makes the construction of a peaceful and sustainable social order a very challenging task, and puts at risk the very survival of human kind. In this paper we want to emphasize the role of the systemic approach, which is proper of OR/MS, with respect to the issue of peace, and in particular within the Peace Studies area.
Interproximal periodontal defect model in dogs: a pilot study
Authors: Jung U‐W , Chang Y‐Y , Um Y‐J , Kim C‐S , Cho K‐S , Choi S‐H
Published: June 2010

Oral Diseases (2010) 17, 26–32

Objective:  This study aimed to evaluate the validity of a surgically created interproximal periodontal defect in dogs.

Materials and methods:  Surgery was performed in the interproximal area between the maxillary second and third premolars in two beagle dogs. Following an incision and reflection of the gingival flap, a 3‐mm wide and 5‐mm high defect was prepared surgically at the interproximal area. A thorough root planing was performed and the flap was coronally positioned and sutured. The contra‐lateral area was served as the control with no surgical intervention. After 8 weeks of healing, the animals were killed and the defect was analysed histometrically and radiographically.

Results:  The interproximal periodontal defect resembled a naturally occurring defect and mimicked a clinical situation. After healing, the defect showed limited bone (0.89 ± 0.02 mm) and cementum regeneration (1.50 ± 0.48 mm).

Conclusions:  Within the limitations of this pilot study, the interproximal periodontal defect showed limited bone and cementum regeneration. Thus, it can be considered as a standardized, reproducible defect model for testing new biomaterials.
Surface three-dimensional velocity map imaging: A new technique for the study of photodesorption dynamics
Authors: Ji Yuanyuan , Koehler Sven P. K. , Auerbach Daniel J. , Wodtke Alec M.
Published: June 2010

The authors describe the application of a combination of velocity map imaging and time-of-flight (TOF) techniques to obtain three-dimensional velocity distributions for surface photodesorption. They have established a systematic alignment procedure to achieve correct and reproducible experimental conditions. It includes four steps: (1) optimization of the velocity map imaging ion optics’ voltages to achieve optimum velocity map imaging conditions; (2) alignment of the surface normal with the symmetry axis (ion flight axis) of the ion optics; (3) determination of TOF distance between the surface and the ionizing laser beam; (4) alignment of the position of the ionizing laser beam with respect to the ion optics. They applied this set of alignment procedures and then measured Br(P23/2) (Br) and Br(P21/2) (Br∗) atoms photodesorbing from a single crystal of KBr after exposure to 193 nm light. They analyzed the velocity flux and energy flux distributions for motion normal to the surface. The Br∗ normal energy distribution shows two clearly resolved peaks at approximately 0.017 and 0.39 eV, respectively. The former is slightly faster than expected for thermal desorption at the surface temperature and the latter is hyperthermal. The Br normal energy distribution shows a single broad peak that is likely composed of two hyperthermal components. The capability that surface three-dimensional velocity map imaging provides for measuring state-specific velocity distributions in all three dimensions separately and simultaneously for the products of surface photodesorption or surface reactions holds great promise to contribute to our understanding of these processes.
Electrical, optical, and structural studies of shallow-buried Au-polymethylmethacrylate composite films formed by very low energy ion implantation
Authors: Teixeira F. S. , Salvadori M. C. , Cattani M. , Brown I. G.
Published: June 2010

The authors present here a summary of their investigations of ultrathin films formed by gold nanoclusters embedded in polymethylmethacrylate polymer. The clusters are formed from the self-organization of subplantated gold ions in the polymer. The source of the low energy ion stream used for the subplantation is a unidirectionally drifting gold plasma created by a magnetically filtered vacuum arc plasma gun. The material properties change according to subplantation dose, including nanocluster sizes and agglomeration state and, consequently also the material electrical behavior and optical activity. They have investigated the composite experimentally and by computer simulation in order to better understand the self-organization and the properties of the material. They present here the results of conductivity measurements and percolation behavior, dynamic TRIM simulations, surface plasmon resonance activity, transmission electron microscopy, small angle x-ray scattering, atomic force microscopy, and scanning tunneling microscopy.
Disposition of the axial ligand in the physical vapor deposition of organometallic complexes
Authors: Kuck Stefan , Prostak Matthias , Funk Markus , Bröring Martin , Hoffmann Germar , Wiesendanger Roland
Published: June 2010

Axial ligands play an important role in the stabilization, functionality, and synthesis of many planar organometallic complexes. Axial ligands are often weakly bound and can easily be activated in catalytic reactions. Thermal activation and following dissociation processes have to be considered whenever sublimation procedures are used for the preparation of well-defined molecular samples under vacuum conditions. When the disposition of the axial ligand is unresolved, this potentially hampers a correct interpretation of experimental data. Here, the authors systematically address the axial ligand (X) in the system of FeIII-TriPhenylCorroles (FeTPC)-X with X=NO, 1/2 O, Cl, and (Et2O)2 adsorbed on Cu(111) in a scanning tunneling microscopy study. The authors discuss undesired side effects due to released axial ligands which are coadsorbed on a surface. NO is identified like the most appropriate axial ligand for in situ preparation of uncoordinated FeTPC whereas the adsorption of axially coordinated FeTPC was not observed.
Surface analysis of polyimide bombarded by charged water droplets
Authors: Hiraoka Kenzo , Sakai Yuji , Iijima Yoshitoki
Published: June 2010

500 eV Ar+ ion impact and the electrospray droplet impact (EDI), in which the charged electrospray water droplets are introduced in vacuum, accelerated and allowed to impact the sample, are applied for etching of polyimide (PI). After the bombardment, x-ray photoelectron spectroscopy (XPS) was applied to the surface analysis. Although oxygen and nitrogen are selectively etched by Ar+ ion impact, the XPS spectra did not change with prolonged charged water droplets irradiation, i.e., EDI is capable of shallow surface etching for PI with little damage of the sample after irradiation.
Properties of thin N-type Yb0.14Co4Sb12 and P-type Ce0.09Fe0.67Co3.33Sb12 skutterudite layers prepared by laser ablation
Authors: Zeipl Radek , Walachová Jarmila , Lorinčík Jan , Leshkov Sergey , Josieková Monika , Jelínek Miroslav , Kocourek Tomáš , Jurek Karel , Navrátil Jiří , Beneš Ludvík , Plecháček Tomáš
Published: June 2010

The properties of thin thermoelectric layers (about 60 nm in thickness) prepared by pulsed laser deposition are presented. Hot pressed targets were made from “middle” temperature range thermoelectric bulk materials with the potential high figure of merit ZT. P-type and N-type layers were prepared from Yb0.19Co4Sb12 and Ce0.1Fe0.7Co3.3Sb12 targets, respectively. The thin films were deposited on quartz glass substrates using KrF excimer laser. The individual layers were prepared by applying different laser beam energy densities (2 or 3 J cm−2) at several substrate temperatures (200, 250, or 300 °C). Crystallinity and composition of the layers were examined by x-ray diffraction and wavelength dispersive analysis, respectively. Homogeneity of Yb across a surface of the Yb filled film was explored by secondary ion mass spectrometry. The thermoelectric properties, the Seebeck coefficient, the electrical resistivity, and the power factor, for the best prepared P and N layer are presented in the temperature range from 300 to 500 K.
Fabrication of plastic biochips
Authors: Saaem Ishtiaq , Ma Kuo-Sheng , Alam S. Munir , Tian Jingdong
Published: June 2010

A versatile surface functionalization procedure based on rf magnetron sputtering of silica was performed on poly(methylmethacrylate), polycarbonate, polypropylene, and cyclic olefin copolymers (Topas 6015). The hybrid thermoplastic surfaces were characterized by x-ray photoelectron spectrometer analysis and contact angle measurements. The authors then used these hybrid materials to perform a sandwich assay targeting an HIV-1 antibody using fluorescent detection and biotinylated peptides immobilized using the bioaffinity of biotin-neutravidin. They found a limit of detection similar to arrays on glass surfaces and believed that this plastic biochip platform may be used for the development of disposable immunosensing and diagnostic applications.
Novel nanoporous carbon materials for adsorption gibberellic acid from solution
Authors: Li Jin , Xia Jin-Tong , Zhang Jun-Hua , Liang Tao
Published: June 2010

Gibberellic acid (GA) is one kind of ubiquitous phytohormones that regulates various developmental processes of the plant growth. Monitoring and controlling the phytohormone is very important to ensure the efficient growth of crops to bring a high yield and quality production in agriculture or horticulture. Since the content of phytohormone in a plant is very low, and easily decomposed by heat, light, and oxygen, it is of considerable interest to the phytohormone research to prepare some specific absorbants for adsorption of phytohormone molecules from the solution. Here, novel nanoporous carbon with tailored pore structure has been synthesized, by dynamic carbonization with silica gel networks as a template, which was formed in sol-gel polycondensation using tetraethoxy silane as a silica precursor and sucrose as a carbon source. The pore structures of this kind of nanoporous carbon can be tunable to a high pore volume of 1.26 cm3/g and a large specific area of 1744 m2/g, which provides an adsorption capacity about 6.8 mg/g to the GA in a solution within 9 h reaction time, and it is over three to four times higher than those to protein and starch in the same solution. This indicated that the prepared nanoporous carbon materials have potential application as a novel absorbent in the separation and purification of GA from the solution for monitoring assay.
Design and fabrication of optical thin films for remote sensing instruments
Authors: Hsiao C. N. , Chen H. P. , Chiu P. K. , Cho W. H. , Lin Y. W. , Chen F. Z. , Tsai D. P.
Published: June 2010

Optical thin films designed for multispectral band-pass filters and a primary Ag mirror were deposited on radiation-resistant glass by ion-beam-assisted deposition. The filters and mirror are for use in the optical payload of a remote sensing instrument. The optical parameters of the films and mirror were optimized by using admittance loci analysis. The simulation shows that the band-pass filters can achieve average transmittances of 95% in the blue (B1), green (B2), red (B3), near-infrared (B4), and panchromatic (400–900 nm) spectral ranges and an average reflectance of 99% for the primary Ag mirror in the visible spectrum. The corresponding properties of the films were investigated by in situ optical monitoring, spectrometry, and high-resolution transmission electron microscopy. It was found that the average transmittances are above 85% for all five band-pass filters, with a rejection transmittance below 1% in the spectral range of 350–1100 nm. The average reflectance of the primary Ag mirror (with a protective coating) is above 98%. Interference coatings were added to the basic protected silver design to enhance the reflectance in the visible spectral range. Furthermore, to investigate the optical stability of optical thin films for aerospace applications, a space environment was simulated by using a Co60 gamma (γ) radiation source (total doses of 35 krad and 1 Mrad). The experimental results indicate that both the dielectric thin film stacks and radiation-protected glass are resistant to γ radiation in the simulated space environment.
Smoking and ulcer perforation
Authors: Svanes C , Søreide J A , Skarstein A , Fevang B T , Bakke P , Vollset S E , Svanes K , Søreide O
Published: June 2010

Background—The use of ulcerogenic drugs is the only well documented risk factor for peptic ulcer perforation, but accounts for only a quarter of the events. Smoking is a well known risk factor for uncomplicated ulcer disease, and patients with ulcer bleeding have increased death rates from smoking related disorders.

Aim—To assess the role of smoking in ulcer perforation.

Subjects—A total of 168 consecutive patients with gastroduodenal ulcer perforation and 4469 control subjects from a population based health survey.

Methods—The association between ulcer perforation and smoking habits was analysed by logistic regression while adjusting for age and sex.

Results—Current smoking increased the risk for ulcer perforation 10-fold in the age group 15–74 years (OR 9.7, 95% CI 5.9 to 15.8) and there was a highly significant dose-response relationship (p<0.001). The results were similar in men (OR 9.3, 95% CI 4.9 to 17) and women (OR 11.6, 95% CI 5.3 to 25), and for gastric (OR 10.5, 95% CI 4.5 to 25) and duodenal (OR 8.6, 95% CI 4.9 to 15.4) ulcer perforation. No increase in risk was found in previous smokers (OR 0.8, 95% CI 0.2 to 2.2).

Conclusion—Our findings suggest that smoking is a causal factor for ulcer perforation and accounts for a major part of ulcer perforations in the population aged less than 75 years.
Gastric ulcer healing in the rat: kinetics and localisation of de novo procollagen synthesis
Authors: Shahin M , Gillessen A , Pohle T , Weber C , Schuppan D , Herbst H , Domschke W
Published: June 2010

Background and aims—To gain further insight into the role of the extracellular matrix during healing of peptic ulcers, sequential changes of procollagen expression were studied over 30 days of ulcer healing.

Materials and methods—Procollagens α1(I), α1(III), and α1(IV) RNA and their polypeptides were assessed in acetic acid induced rat gastric ulcers by in situ hybridisation and immunohistochemistry.

Results—Three days after ulcer induction, intense hybridisation signals were obtained with all probes, with procollagen α1(I) showing the highest transcript levels. Procollagen gene expression remained elevated up to day 15, but was reduced to initial low levels on day 30. Immunohistochemical staining documented increased deposition of the three procollagen types parallel to their respective transcript levels, again with type I showing the earliest and the most prominent deposits. The highest procollagen transcript levels were found in the intact submucosa surrounding the ulcer margins, followed by the muscularis propria and the serosa, with the lamina propria exhibiting the lowest transcript levels.

Conclusion—The procollagens studied are regulated differentially at the transcriptional and post-transcriptional levels. The early onset and long duration of procollagen expression as well as the involvement of all layers of the gastric wall points to their central structural and functional role in gastric ulcer healing.
K-ras mutations in patients with early colorectal cancers
Authors: Andreyev H J N , Tilsed J V T , Cunningham D , Sampson S A , Norman A R , Schneider H J , Clarke P A
Published: June 2010

Background—Published data are contradictory about the importance of K-ras mutations in advanced tumours and are not available for early cancers.

Aims—To establish whether specific K-ras mutations are prognostic markers in early stage colorectal adenocarcinoma.

Methods—The presence of K-ras exon 1 mutations were correlated with tumour recurrence in two groups of patients: group 1 was a consecutive series of patients with resected colorectal adenocarcinoma at low risk of recurrence; group 2 were patients referred for chemotherapy after relapse of previously resected early stage tumours. K-ras mutations were detected by direct sequencing of whole tissue samples in all patients and in some, the leading edge and centre of the tumour were also microdissected out individually and sequenced.

Results—Mutations were present in 26 (26.5%) of 98 patients in group 1; 14 patients developed a recurrence, four (28.5%) of whom had a K-ras mutation. Seventy nine patients have not developed tumour recurrence, 22 (28%) of whom had a mutation (p=0.84). K-ras mutations were present in five of 14 patients in group 2. Microdissection did not increase the number of mutations detected.

Conclusions—Individual K-ras genotypes are distributed homogeneously throughout early stage colorectal adenocarcinomas, but detection of a mutation has no apparent prognostic value.
Elevated calcium and activation of trypsinogen in rat pancreatic acini
Authors: Frick T W , Fernández-del-Castillo C , Bimmler D , Warshaw A L
Published: June 2010

Background—Acute pancreatitis associated with hypercalcaemia has been described in humans and experimental animals. It has been demonstrated that calcium dose dependently accelerates trypsinogen activation, and it is generally believed that ectopic activation of digestive enzymes is an early event in the pathophysiology of acute pancreatitis.

Aims and methods—Trypsinogen activation peptide (TAP) was measured in isolated rat pancreatic acini exposed to elevated extracellular calcium in order to investigate the association between calcium and trypsinogen activation in living cells. TAP was determined in the culture medium either before (extracellular compartment) or after (intracellular compartment) cell homogenisation.

Results—Neither secretory stimulation nor elevated calcium alone caused an increase in TAP levels. Maximal cerulein or carbachol stimulation superimposed on high medium calcium, however, significantly increased intracellular trypsinogen activation twofold. This increase was inhibited by eitherNG-monomethyl-l-arginine (l-NMMA) or verapamil. Acinar cell morphology and function remained intact as demonstrated by electron microscopy and secretagogue dose-response studies.

Conclusions—These results support the hypothesis that increased intracellular trypsinogen activation is an early step in the pathogenesis of hypercalcaemia induced pancreatitis. The model may have a bearing on other types of pancreatitis as elevated cytosolic calcium is thought to be an early event in the pathogenesis of acute pancreatitis in general.
Hirschsprung’s disease: genetic mutations in mice and men
Authors: ROBERTSON K , MASON I , HALL S
Published: June 2010

Hirschsprung’s disease is a neuronal dysplasia of the hindgut, characterised by a loss of neurones, which affects about 1 in 5000 live births.1 Genetic factors have been implicated in the aetiology of this disease in about 20% of cases and a dominant pattern of inheritance has been revealed in several families.2
3The pathogenesis of the aganglionosis is often attributed to a failure of migration of neural crest cells, although this has not been proven.

Recently, mutations in a developmentally regulated receptor tyrosine kinase gene, ret, and mutations in the endothelin receptor-B gene (ENDR-B) have both been linked to familial Hirschsprung’s disease in humans.4-6 Moreover, certain mutant mouse strains—namely piebald lethal and lethal spotted—exhibit striking similarities to the human condition. The mutation which gives rise to piebald lethal has now been found to be in the ENDR-B gene,7 and the mutation associated with lethal spotted occurs in the gene for endothelin-3 (ET-3), a ligand for ENDR-B.8

Two transgenic mouse lines have been developed which also reflect the human disease: ret-k−, which has aloss of function mutation of the retgene,9 and ENDR-B null.10 In addition, the introduction of a Lac-Z reporter gene into neural crest cells of aganglionic mice has made it possible to study directly the fate of enteric neuroblasts which are affected by “Hirschsprung’s-like” mutations.11 Here, we review the possible roles of RET and endothelin in the normal development of the enteric nervous system, and the significance of their mutated forms in the pathogenesis of familial aganglionosis.

This review focuses on recent advances in our understanding of the genetic basis of the lesions which have been implicated in congenital forms of Hirschsprung’s disease. Disruption of these genes in the mouse, either by transgenic “knockout” approaches or in mutant mouse lines, offers the prospect of greater understanding of both the cellular and developmental bases of the human disease.
Endoscopic papillary balloon dilatation may preserve sphincter of Oddi function after common bile duct stone management: evaluation from the viewpoint of endoscopic manometry
Authors: Sato H , Kodama T , Takaaki J , Tatsumi Y , Maeda T , Fujita S , Fukui Y , Ogasawara H , Mitsufuji S
Published: June 2010

Background—Endoscopic papillary balloon dilatation (EPBD) has been reported as a safe and effective alternative to endoscopic sphincterotomy in the management of common bile duct (CBD) stones; its effect on papillary function has yet to be elucidated.

Aim—To investigate sphincter of Oddi (SO) motility before and after EPBD to determine its effect on SO function.

Patients and methods—The papillary function of 10 patients with CBD stones was studied using endoscopic manometry before and one week after EPBD. The manometric studies were repeated one month after EPBD in seven patients.

Results—One week after EPBD, CBD pressure, SO peak pressure, SO basal pressure, and SO frequency decreased significantly. One month after EPBD, however, all parameters increased although the increases in SO basal pressure and CBD pressure were not significant. There was no significant difference in values of any parameter before and one month after EPBD. No serious complications occurred.

Conclusion—These data suggest at least partial recovery of papillary function one month after the procedure. EPBD seems to preserve papillary function in treatment of CBD stones; a longer term follow up study with SO manometry should be performed to clarify the effect of EPBD on SO function.
Influencing the practice and outcome in acute upper gastrointestinal haemorrhage
Authors: Rockall T A , Logan R F A , Devlin H B , Northfield T C
Published: June 2010

Aims—To assess changes in practice and outcome in acute upper gastrointestinal haemorrhage following the feedback of data, the reemphasis of national guidelines, and specific recommendations following an initial survey.

Design—A prospective, multicentre, audit cycle. Forty five hospitals from three health regions participed in two phases of the audit cycle.

Patients—Phase I: 2332 patients with acute upper gastrointestinal haemorrhage; phase II: 1625 patients with upper gastrointestinal haemorrhage.

Methods—Patients were evaluated with respect to management (with reference to the recommendations in the national guidelines), mortality, and length of hospital stay.

Results—Following the distribution of data from the first phase of the National Audit and the formulation of specific recommendations for improving practice, the proportion of hospitals with local guidelines or protocols for the management of upper gastrointestinal haemorrhage rose from 71% (32/45) to 91% (41/45); 12 of the 32 hospitals with guidelines during the first phase revised their guidelines following the initial survey. There was a small but significant increase in the proportion of all patients who underwent endoscopy (from 81% to 86%), the proportion who underwent endoscopy within 24 hours of admission (from 50% to 56%), and the use of central venous pressure monitoring in patients with organ failure requiring blood transfusion or those with profound shock (from 30% to 43%). There was, however, no change in the use of high dependency beds or joint medical/surgical management in high risk cases. There was no significant change in crude or risk standardised mortality (13.4% in the first phase and 14.4% in the second phase).

Conclusions—Although many of the participating hospitals have made efforts to improve practice by producing or updating guidelines or protocols, there has been only a small demonstrable change in some areas of practice during the National Audit. The failure to detect any improvement in mortality may reflect this lack of change of practice, but may also reflect the fact that a large proportion of the deaths in this unselected study are not preventable; only a very large study could hope to demonstrate a significant change out of the context of a clinical trial.
Antisecretory factor suppresses intestinal inflammation and hypersecretion
Authors: Johansson E , Jennische E , Lange S , Lönnroth I
Published: June 2010

Background—Antisecretory factor (AF) is a recently identified regulatory protein which inhibits the intestinal fluid secretion induced by cholera toxin.

Aims—To test the effect of AF on: (a) inflammation and hypersecretion induced by toxin A fromClostridium difficile; and (b) morphological changes and hypersecretion induced by okadaic acid (the blue mussel toxin) in rat intestinal mucosa.

Methods—Morphological changes and fluid accumulation were observed in intestinal loops challenged with 1 μg of toxin A or 3  μg of okadaic acid administered before or after injection of 0.1  μg of recombinant AF (rAF).

Results—The cytotoxic and inflammatory reaction caused by toxin A was abolished after treatment with rAF given either intraveneously or intraluminally prior to the toxin or one hour after the toxin. The intestinal fluid response induced by toxin A and okadaic acid was reduced 55–80% by rAF. However, the characteristic increase in goblet cells at the tips of villi in the okadaic acid treated mucosa was not inhibited by rAF.

Conclusion—Results suggest that AF might be involved in protection against inflammation and in counteracting dehydration caused by enterotoxins. Both effects are probably mediated via the enteric nervous system.