bluuebunny/crossref_metadata_2025 huggingface dataset:
On witnessed models in fuzzy logic
Authors: Hájek Petr
Published: January 2007

Witnessed models of fuzzy predicate logic are models in which each quantified formula is witnessed, i.e. the truth value of a universally quantified formula is the minimum of the values of its instances and similarly for existential quantification (maximum). Systematic theory of known fuzzy logics endowed with this semantics is developed with special attention paid to problems of arithmetical complexity of sets of tautologies and of satisfiable formulas. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Small skew fields
Authors: Milliet Cédric
Published: January 2007

A small field of positive characteristic is commutative. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neumann problems for nonlinear hemivariational inequalities
Authors: Hu Shouchuan , Papageorgiou Nikolaos S.
Published: January 2007

In this paper we study nonlinear Neumann problems driven by the p ‐Laplacian and having a nonsmooth potential. Using techniques from the nonsmooth critical point theory, we prove two existence theorems and a multiplicity result. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lower limb nerve injuries in children
Authors: Senes Filippo M. , Campus Riccardo , Becchetti Flavio , Catena Nunzio
Published: January 2007

The aim of this paper is to emphasize the seriousness of pediatric peripheral nerve injuries of lower limbs and to stress the importance of early exploration of the injured nervous trunk in order to reduce the number of unfavorable outcomes. Among 136 traumatic peripheral nerve injuries in the children we treated, 31 nerve injuries of the lower limbs were observed. Causes of injury and time to recovery were evaluated. The sciatic nerve was involved in 19 cases, peroneal nerve in 11, root avulsions of the spinal cord in 1. We observed complete recovery in 12 cases and incomplete or no recovery at all in 19. The mean time to recovery in patients who underwent surgery was 18 months (range: 1–32). Considering the rate of spontaneous recovery of postinjection nerve injuries of the sciatic nerve and early onset of skeletal deformities, a closed nerve injury of the lower limb with no recovery within 3 months should always undergo surgery, even if complete functional outcome is not always guaranteed. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
ApproximateL(δ1,δ2,…,δt)‐coloring of trees and interval graphs
Authors: Bertossi Alan A. , Pinotti Cristina M.
Published: January 2007

Given a vector (δ1,δ2,…,δt) of nonincreasing positive integers, and an undirected graphG= (V,E), anL(δ1,δ2,…,δt)‐coloring ofGis a functionffrom the vertex setVto a set of nonnegative integers such that ∣f(u) −f(v)∣ ≥ δi, ifd(u,v) =i, 1 ≤i≤t, whered(u,v) is the distance (i.e., the minimum number of edges) between the verticesuandv. An optimalL(δ1,δ2,…,δt)‐coloring forGis one minimizing the largest integer used over all such colorings. Such a coloring problem has relevant applications in channel assignment for interference avoidance in wireless networks. This article presents efficient approximation algorithms forL(δ1,δ2,…,δt)‐coloring of two relevant classes of graphs—trees, and interval graphs. Specifically, based on the notion of strongly simplicial vertices,O(n(t+ δ1)) andO(nt2δ1) time algorithms are proposed to find α‐approximate colorings on interval graphs and trees, respectively, wherenis the number of vertices and α is a constant depending ontand δ1,…,δt. Moreover, anO(n) time algorithm is given for theL(δ1,δ2)‐coloring of unit interval graphs, which provides a 3‐approximation. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(3), 204–216 2007
Leonhard Euler: A brief appreciation
Authors: Assad Arjang A.
Published: January 2007

April 15, 2007, marks the 300th anniversary of Leonhard Euler's birth. This article pays tribute to the great mathematician who originated graph theory. We provide an overview of his life and his mathematical works, with particular emphasis on the historical development of the concept of Euler paths and cycles. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(3), 190–198 2007
Preconditioners for the discretized time‐harmonic Maxwell equations in mixed form
Authors: Greif Chen , Schötzau Dominik
Published: January 2007

We introduce a new preconditioning technique for iteratively solving linear systems arising from finite element discretization of the mixed formulation of the time‐harmonic Maxwell equations. The preconditioners are motivated by spectral equivalence properties of the discrete operators, but are augmentation free and Schur complement free. We provide a complete spectral analysis, and show that the eigenvalues of the preconditioned saddle point matrix are strongly clustered. The analytical observations are accompanied by numerical results that demonstrate the scalability of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd.
On multiscale FE analyses of heterogeneous structures: from homogenization to multigrid solvers
Authors: Miehe C. , Bayreuther C. G.
Published: January 2007

Heterogeneous structures like composites often need a fine‐scale resolution of micro‐effects which influence the macroscopic overall response. This is of particular relevance in the fully non‐linear range of large strains and inelastic material response of the constituents. Suitable solution methods introduce a multifield scenario of hierarchically superimposed states on different length scales. For big differences of micro‐ and macro‐scales, the argument of scale separation induces the application of homogenization methods. Such types of physical multiscale approaches can be treated by nested multilevel finite element analyses that discretize both the fine‐scale micro‐structure as well as the macroscopic boundary‐value problem. In contrast, small‐scale differences require full resolution of the heterogeneous structure. Effective solution methods for the resulting large‐scale problems with strongly oscillating properties are suitably designed geometric multigrid techniques, which may be considered as numerical multiscale approaches. In both scenarios, a key ingredient is the suitable formulation of scale bridging algorithms that govern the transfer between different scales. The paper outlines new mesh‐bridging techniques in a deformation‐driven context for fully non‐linear response, which exploit in a non‐trivial manner weak constraints on the average deformation in typical finite element patches. The framework is based on an incremental variational structure of finite inelasticity. The proposed new formulations provide variational‐based homogenization algorithms for physical multiscale scenarios and problem‐dependent optimal finite element grid transfers for numerical multiscale scenarios of heterogeneous materials. Copyright © 2007 John Wiley & Sons, Ltd.
Deposition of highly efficient microcrystalline silicon solar cells under conditions of low H2 dilution: the role of the transient depletion induced incubation layer
Authors: van den Donker M. N. , Rech B. , Finger F. , Houben L. , Kessels W. M. M. , van de Sanden M. C. M.
Published: January 2007

This paper addresses the plasma deposition of highly efficient microcrystalline silicon (μc‐Si:H) p‐i‐n solar cells under conditions of high SiH4 utilization and low H2 dilution. It was established that the transient depletion of the initially present SiH4 source gas induces the formation of an amorphous incubation layer that prevents successful crystallite nucleation in the i‐layer and leads to poor solar cell performance. The effect of this transient depletion induced incubation layer on solar cells was made visible through dedicated solar cell deposition series and selected area electron diffraction measurements. Applying a gas flow procedure at plasma ignition it was succeeded to prepare state‐of‐the‐art μc‐Si:H material and solar cells under low hydrogen dilution conditions, highlighted by μc‐Si:H solar cells of up to 9·5% efficiency prepared using an undiluted source gas flow consisting solely of SiH4. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling the influence of the orientation and fibre reinforcement on the Negative Poisson's ratio in composite laminates
Authors: Hadi Harkati El , Bezazi Abderrezak , Scarpa Fabrizio , Alderson Kim , Alderson Andrew
Published: January 2007

The variation of through‐thickness Poisson's ratio with fibre type and orientation has been investigated using a specially developed Fortran program. Glass fibre/epoxy resin composites were always found to be conventional, but negative Poisson's ratio values of up to ν13 = –0.746 were produced over certain orientation angles for Kevlar and carbon reinforcements. This underlines the need for anisotropic pre‐preg material. A range of [±β /±θ ]s angles were investigated for carbon fibre laminates and it was found that auxetic behaviour could be generated for β up to 45°. All the findings of this work have extended the range of laminates which can be engineered to be auxetic either by material (i.e. Kevlar as well as carbon) or by orientation (i.e. by introducing further β layers other than the 0° and 90° previously investigated). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement and analysis of truck and rail shipping environment in India
Authors: Singh S. P. , Sandhu A. P. S. , Singh J. , Joneson E.
Published: January 2007

Free trade agreements have been on the rise in all regions of the world in the past decade. This has allowed for global distribution and marketing of products in an international market. Products once produced for domestic markets must now be able to compete in international markets without trade barriers. Increased international commerce and manufacturing have forced many packaging and logistics engineers to broaden their true understanding of the global distribution environment. India is a recent entrant on the global arena for manufacturing and services. While China's economic developments have dominated global headlines, India's own growth has been impressive as well, with a gross domestic product rising 5% per annum on average since 1990. India is hence primed to follow China as the next low‐cost manufacturing super power. With an increasing interest from multinational corporations in conducting commerce with India, there arises a great need to understand the conditions of the transportation infrastructure there to promote logistical understanding of the distribution environments. This paper provides a brief overview of the road and rail transportation environment in India. It also provides the results of a 2 year study that measured and analysed truck and rail transport vibration for the major freight distribution routes between New Delhi, Bangalore, Mumbai, Chennai, Hyderabad and Kolkatta. Copyright © 2007 John Wiley & Sons, Ltd.
Students' mental models of the environment
Authors: Shepardson Daniel P. , Wee Bryan , Priddy Michelle , Harbor Jon
Published: January 2007

What are students' mental models of the environment? In what ways, if any, do students' mental models vary by grade level or community setting? These two questions guided the research reported in this article. The Environments Task was administered to students from 25 different teacher‐classrooms. The student responses were first inductively analyzed in order to identify students' mental models of the environment. The second phase of analysis involved the statistical testing of the identified mental models. From this analysis four mental models emerged: Model 1, the environment as a place where animals/plants live—a natural place; Model 2, the environment as a place that supports life; Model 3, the environment as a place impacted or modified by human activity; and Model 4, the environment as a place where animals, plants, and humans live. The dominant mental model was Mental Model 1. Yet, a greater frequency of urban students than suburban and rural students held Mental Model 3. The implications to environmental science education are explored. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 327–348, 2007
By how much does increased nuchal translucency increase the risk of adverse pregnancy outcome in chromosomally normal fetuses? A study of 16 260 fetuses derived from an unselected pregnant population
Authors: Westin M. , Saltvedt S. , Almström H. , Grunewald C. , Valentin L.
Published: January 2007

Objective

In this study we aimed to estimate the magnitude of a possible increase in risk of adverse outcome in fetuses with normal karyotype and increased nuchal translucency (NT), and to determine how well NT measurements can distinguish between fetuses with normal and adverse outcome.

Methods

We studied 16 260 consecutive fetuses with normal karyotype derived from an unselected pregnant population. The following cut‐offs for increased risk of adverse outcome were chosen a priori: NT ≥ 95th percentile, ≥ 3 mm, ≥ 3.5 mm, and ≥ 4.5 mm. The positive and negative likelihood ratios (+LR, − LR) of the risk cut‐offs with regard to fetal malformation, miscarriage, perinatal death, termination of pregnancy and total adverse outcome were calculated, and receiver–operating characteristics (ROC) curves were drawn.

Results

The total rate of adverse outcome was 2.7%. + LR and − LR of NT ≥ 3.0 mm were: for lethal or severe malformation, + LR 15.0 (95% CI 7.0–28.6), − LR 0.89 (95% CI 0.81–0.95); for malformation of at least intermediate severity, + LR 8.1 (95% CI 4.3–14.0), − LR 0.95 (95% CI 0.92–0.97); for termination of pregnancy, + LR 41.6 (95% CI 17.1–86.6), − LR 0.67 (95% CI 0.41–0.85); for any adverse outcome, + LR 6.4 (95% CI 3.4–11), − LR 0.96 (95% CI 0.94–0.98). The odds for these adverse outcomes increased with increasing NT. NT ≥ 3 mm did not significantly increase the risk of miscarriage or perinatal death. Areas under ROC curves for NT were small, with 95% CI below or only slightly above 0.5.

Conclusion

Our likelihood ratios can be used to calculate the individual risk of unfavorable outcome, but NT screening cannot reliably distinguish between normal and adverse outcome in fetuses with normal karyotype. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Synthesis, structure and magnetic properties ofβ-MnO
2
nanorods
Authors: Kim HaeJin , Lee JinBae , Kim Young-Min , Jung Myung-Hwa , Jagličić Z. , Umek P. , Dolinšek J.
Published: January 2007

We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO2nanorods of 50–100 nm diameter and several µm length. Thorough structural characterization shows that the basic β-MnO2material is covered by a thin surface layer (∼2.5 nm) of α-Mn2O3phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO2nanorods. The relatively complicated temperature-dependent magnetism of the nanorods can be explained in terms of a superposition of bulk magnetic properties of spatially segregated β-MnO2and α-Mn2O3constituent phases and the soft ferromagnetism of the thin interface layer between these two phases.
An asymmetric Neumann problem with weights
Authors: Gossez J.-P. , Arias M. , Campos J. , Cuesta M.
Published: January 2007

We prove the existence of a first nonprincipal eigenvalue for an asymmetric Neumann problem with weights involving the

p

-Laplacian (cf. (1.2) below). As an application we obtain a first nontrivial curve in the corresponding Fučik spectrum (cf. (1.4) below). The case where one of the weights has meanvalue zero requires some special attention in connexion with the (PS) condition and with the mountain pass geometry.

Nous démontrons l'existence d'une première valeur propre non principale pour un problème de Neumann asymétrique avec poids faisant intervenir le

p

-laplacien (cf. (1.2) ci-dessous). Comme application nous obtenons une première courbe non triviale dans le spectre de Fučik correspondant (cf. (1.4) ci-dessous). Le cas où l'un des poids est de moyenne nulle demande une attention particulière en liaison avec la condition de Palais–Smale et avec la géométrie du col.
Clinical‐pathological study of the healing of wounds provoked on the dorso‐lingual mucosa in 186 albino rats
Authors: Camacho‐Alonso Fabio , López‐Jornet Pía
Published: January 2007

OBJECTIVE

To evaluate wound healing of incisions created in the upper aerodigestive tract.

STUDY DESIGN AND SETTING

In this prospective and blind study, 186 adult rats were assigned to six groups to create incisions in the tongue. In the first three groups, the wounds were made with a steel scalpel; no substance was applied to the wound in the first group, but N‐butyl‐2‐cyanoacrylate was applied in the second group, and trichloroacetic acid at 50 percent in the third group. In the fourth, fifth, and sixth groups, the wounds were caused by cryosurgery, electrocautery, and CO2 laser. Hemostasis, postoperative oral intake, and wound healing were measured. Statistical analysis was performed with analysis of variance.

RESULTS

The wounds to which N‐butyl‐2‐cyanoacrylate was applied showed no hemorrhaging and faster reepithelialization and resolution of the inflammatory response.

CONCLUSIONS

N‐butyl‐2‐cyanoacrylate is a good hemo‐static for managing wounds in the oral mucosa provoked by steel scalpel.

© 2007 American Academy of Otolaryngology‐Head and Neck Surgery Foundation. All rights reserved.
Propofol versus sevoflurane: Bleeding in endoscopic sinus surgery
Authors: Beule Achim G. , Wilhelmi Frank , Kühnel Thomas S. , Hansen Ernil , Lackner Karl J. , Hosemann Werner
Published: January 2007

OBJECTIVE

Reduction of intraoperative bleeding is desirable to improve intraoperative visibility and to avoid complications.

STUDY DESIGN

Prospective, controlled, randomized, double‐blinded study.

SETTING

Inclusion criteria were chronic rhinosinusitis with nasal polyps that involved all paranasal sinuses, Lund‐CT score ≤ 12, and double‐blind preoperative randomization of narcotics. Exclusion criteria included abnormal coagulation, perioperative blood pressure outside the range of 70 to 140 mmHg systolic and 50 to 90 mmHg diastolic and perioperative medication. Total blood loss (mL), blood loss per minute (mL/min), platelet function, and parameter for endoscopic vision were evaluated.

RESULTS

Forty‐six patients (22 sedated with sevoflurane/fentanyl, 24 sedated with propofol/fentanyl) completed the study. Total blood loss (300.1 ± 168.5 mL/276.9 ± 201.3 mL), blood loss per minute, and endoscopic vision showed no group difference. Platelet function was significantly impaired 45 minutes after onset of surgery in both groups, but more pronounced after propofol anesthesia.

CONCLUSION

Under conditions of balanced circulatory parameter, equal blood loss and endoscopic vision can be achieved with both tested anesthetic regimens. During extended operations demonstrated thrombocyte impairment by propofol may become clinically relevant.

© 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
Endoscopic versus external repair of orbital blowout fractures
Authors: Jin Hong‐Ryul , Yeon Je‐Yeob , Shin See‐Ok , Choi Young‐Seok , Lee Dong‐Wook
Published: January 2007

OBJECTIVES

This study evaluates the usefulness of endoscopic repair compared to external repair in the treatment of blowout fracture (BOF) of the orbit.

STUDY DESIGN AND SETTING

This retrospective study comprised 100 patients who had had surgical repair of orbital BOF since 1992. Forty‐eight of the 100 had undergone endoscopic repair, 48 patients had had external repair, and four patients underwent surgery that combined the two approaches. The two basic approaches were evaluated and compared with respect to technique, results and complications.

RESULTS

Endoscopically, transnasal and transantral approaches had been used for reduction and support of fractured medial and inferior walls, respectively. In the external approach, various transorbital incisions were made and the fractured wall was repaired with alloplastic or autologous materials. Complete or partial resolution of preoperative diplopia was achieved in 94% of the endoscopic group and 83% of the external group (NS). Enophthalmos was improved in 89% of the endoscopic group and 76% of the external group (NS). Though the endoscopic group had no significant complications, the external group had ectropions, significant facial scars, extrusion of inserted Medpor, and intra‐orbital hematoma.

CONCLUSIONS

Endoscopic repair appears to be a safe and effective technique for the treatment of BOF of the orbit.

© 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
Eighteenth Century Travelogues as Models for ‘Rethinking Europe’
Authors: ANDERSEN FRITS
Published: January 2007

Travelogues on expeditions in the 1760s to Tahiti and Yemen among other places are part of the early reshaping of Europe. They display the features of a historical threshold or ‘Sattelzeit’ between the classical and the modern world. But these travelogues also demonstrate another paradigmatic shift with important impact on the conditions for thinking of Europe in present day literary history. Some travelogues inaugurate in their rhetorical practice and anthropological content a problematic cultural relativism and aestheticism in relation to the world outside Europe. Other texts express doubts and contradictions, hesitating without being relativistic, focusing on cultural processes and concrete specifics rather than on essences, and adopting a pluridimensional perspective on the customs the traveller is confronted with. While the former track leads to the dead-end of reductive schematism of 19th century Orientalism, the latter may serve as a relevant model for rethinking Europe as part of a globalised world today. In what follows, the travel writing on Tahiti by James Cook, Bougainville and Diderot, Carsten Niebuhr's travelogue from his expedition to Yemen, Flaubert's Voyage en É:gypte, and Gauguin's NoaNoa, are analysed.
Delivering multidisciplinary public health in action – the Cardiff Food Strategy case study
Authors: Fairchild Ruth M , Morgan Maria Z
Published: January 2007

Background

There is an increasing awareness that the provision of healthy food relies on the co-ordinated efforts of a number of diverse disciplines, not merely those traditionally linked with food. This paper documents the development of a food and health strategy, commissioned by the health alliance for the city of Cardiff, and focuses on the areas of sustainability, education and training as well as nutrition, food provision and food safety.

Objective

The aim of the strategy was to increase the uptake of a healthy, safe and sustainable diet for all those living in Cardiff.

Method

The methodology included a rapid appraisal of food initiatives operating within the city, establishing a food and health strategy working group and the production of strategy documentation. Multi-agency collaboration and consultation were key components of the approach.

Results

As the strategy developed, seven action areas became apparent, including education and training, public sector procurement and rewarding excellence. These action areas were incorporated into seven ‘action tables’, which constitute the core of the strategy. The food and health strategy document was ratified by the Local Health Alliance board in August 2004. But, far greater benefits were realised as a consequence of setting up the strategy working group. Long before the document was written, the strategy process was operating as ‘multidisciplinary public health in action’.

Conclusion

The network that comprised the food and health strategy working group was already able to commence delivery of a more integrated approach to food and health within Cardiff.
Impact of nutrients on insulin-like growth factor-I, insulin-like growth factor binding protein-3 and their ratio in African American and white males
Authors: McGreevy Katharine M , Hoel Brian D , Lipsitz Stuart R , Hoel David G
Published: January 2007

Objective

Higher levels of insulin-like growth factor-I (IGF-I) and lower levels of IGF binding protein-3 (IGFBP-3) have been associated with an increased risk of prostate cancer. Nutrition is known to partially regulate IGF levels and it is possible that nutritional factors mediate the impact of IGF levels on prostate cancer risk.

Design

A cross-sectional analysis of the impact of nutritional factors measured by a dietary questionnaire on plasma levels of IGF-I, IGFBP-3 and their molar ratio. Multiple linear regression analysis was used to test for effects of nutrients on IGF levels.

Setting

Prostate cancer screening at the Hollings Cancer Center in Charleston, South Carolina.

Subjects

Ninety-five African American and 138 white males aged 33–83 years attending the screening.

Results

In whites, intakes of total, saturated and monounsaturated fats were positively associated with an increase in the molar ratio, while there was no association in African Americans. In African Americans, we found that increasing intake of calcium and dairy servings was positively associated with IGF-I levels. Increased vegetable intake was positively associated with IGFBP-3 in African Americans, while there was no effect in whites. A higher percentage of alcohol in the total diet was significantly associated with a decrease in the molar ratio and an increase in IGFBP-3 in both groups.

Conclusions

Our results confirm previous findings of nutritional determinants of IGF levels. Additionally, we found the impact of several nutrients on IGF levels to be different in whites and African Americans, which warrants further investigation.
The role of breakfast in nutrient intake of urban schoolchildren
Authors: Chitra Uma , Reddy C Radha
Published: January 2007

Objectives

To ascertain the breakfast habits of 10–15-year-old schoolchildren and to assess the quality of this meal as well as its relationship to the food consumption pattern for the full day.

Design

Cross-sectional survey.

Subjects and setting

Eight hundred and two schoolchildren, boys and girls, aged 10–15 years, belonging to different urban schools located in Secunderabad, Andhra Pradesh, India.

Method

The breakfast eating patterns of the children were studied and their impact on growth was assessed, using dietary recalls and anthropometric measurements.

Results

Only 42.8% of the children ate breakfast regularly. Over half of the children skipped breakfast, ranging from daily to once in two weeks. The energy and protein composition of breakfasts eaten by the children indicated that those who did not skip breakfast met one-quarter to one-third of their total daily energy and protein requirements. Mean nutrient intakes calculated from 24-hour recalls revealed that the children's diets were inadequate compared with the recommended values for energy and protein. The inadequate energy intake was reflected in a high incidence of malnutrition in both boys and girls; 40.3% of the boys and 32.1% of the girls studied were found to be underweight. Protein intake was also inadequate among boys and girls, although a higher percentage of children met their protein requirements.

Conclusions

Over half of the schoolchildren studied skipped breakfast frequently, the main reason being getting up late. Children who consumed breakfast had higher daily intakes of energy and protein than children who skipped breakfast. These data confirm the importance of breakfast to overall dietary quality and adequacy in school-aged children.
Medikamentöse Therapie des Morbus Parkinson
Authors: Waldvogel
Published: January 2007

Unser konzeptuelles Verständnis der Parkinson’schen Erkrankung hat sich in den letzten Jahren stark gewandelt. Wir verstehen heute unter Parkinson nicht nur eine Erkrankung des motorischen Systems, sondern auch eine Erkrankung mit nicht-motorischen Symptomen, deren Bedeutung für die Lebensqualität des Patienten und der Angehörigen enorm ist. Nach Jahren der Erkrankung kommen obligat Komplikationen der Therapie hinzu. Nach dem Vorliegen nicht-motorischer Symptome und Therapiekomplikationen soll aktiv gefragt werden, da sie oft weder von den Patienten noch den Angehörigen spontan mitgeteilt werden, sei es aus Scham, sei es, dass sie nicht als mit dem Parkinson assoziierte Probleme erkannt werden. Eine zufriedenstellende Therapie der Parkinson’schen Erkrankung setzt das Erkennen und Behandeln aller Symptome voraus, weshalb im folgenden Artikel auch auf die nicht-motorischen Probleme und Therapiekomplikationen eingegangen werden soll.
Chirurgische Therapie des Morbus Parkinson
Authors: Kaelin-Lang  , Stibal
Published: January 2007

In den letzten Jahren haben chirurgische Eingriffe bei M. Parkinson eine Renaissance erlebt. Hauptgrund ist die so genannte «tiefe Hirnstimulation», die fast überall die früher üblichen stereotaktischen Läsionen verdrängt hat. Anstatt Gewebe irreversibel zu zerstören, wird bei der «tiefen Hirnstimulation» eine spezifische Region der Basalganglien mit einer Elektrode elektrisch stimuliert. Insbesondere die bilaterale Stimulation des Nucleus subthalamicus hat sich als chirurgische Therapie der Wahl bei M. Parkinson etabliert. Aber auch die «tiefe Hirnstimulation» des Globus pallidus oder des Thalamus ist bei einzelnen Patienten weiterhin indiziert. Die tiefe Hirnstimulation ist eine sehr effiziente Methode zur symptomatischen Behandlung der motorischen Komplikationen des M. Parkinson, die unter medikamentöser Therapie nicht mehr befriedigend eingestellt werden können. Insbesondere Dyskinesien, Bradykinesie, Tremor und Rigor können gut behandelt werden und die medikamentöse Therapie oft reduziert werden. Wie weit die Besserung dieser motorischen Symptome langfristig die Lebensqualität verbessert ist aber noch ungenügend belegt. Bei Patienten mit schweren kognitiven und psychiatrischen Symptomen oder mit schweren axialen Symptomen wie Schluckstörungen ist ein Eingriff gut abzuwägen, da sich diese Symptome postoperativ verschlechtern können.
Rehabilitation von Parkinsonpatienten
Authors: Baronti
Published: January 2007

Die meisten Parkinsonpatienten profitieren von einer sorgfältig individualisierten medikamentösen Therapie, bei einigen kann die Möglichkeit einer funktionellen neurochirurgischen Intervention zusätzlich diskutiert werden. Trotzdem sollte sich das Management von M. Parkinson nicht auf diese zwei Optionen – deren Resultate noch unbefriedigend bleiben – beschränken: eine Kombination interdisziplinärer Interventionen ist dringend zu empfehlen. Neben dem Hausarzt und dem Neurologen können Physio-, Ergo- und Logotherapeuten signifikant zur Selbstständigkeit und Lebensqualität der Betroffenen beitragen; zudem ist die psychosoziale Unterstützung des betreuenden Umfeldes in einigen Fällen unumgänglich. Die Beratung durch spezialisierte Pflegepersonen kann die Auswirkung im Alltag von Begleitsymptomen wie Inkontinenz, symptomatische Orthostase oder Speichelfluss lindern. Trotz (noch) fehlender wissenschaftlicher Untermauerung weisen viele Studien auf die Wirksamkeit dieser Maßnahmen, die bereits zu den Standards of Care von M. Parkinson gehören, hin. Rehabilitatorische Interventionen können pharmako-resistente Symptome und medikamentöse Nebenwirkungen günstig beeinflussen; zudem sind sie bei sekundären Parkinsonsyndromen die einzige Möglichkeit, das Fortschreiten der Behinderung zu verlangsamen. Rehabilitationsmethoden, welche die neurophysiologischen Erkenntnisse über die Krankheit berücksichtigen und den Patienten Strategien zur Bewältigung des Alltags vermitteln, sollten bevorzugt werden.
Chorea
Authors: Vieregge
Published: January 2007

Mit Chorea (griechisch: «Tanz») bezeichnet der Neurologe unwillkürliche, unregelmäßige, kurzzeitige, nichtrepetitive und zufällig verteilte Muskelkontraktionen mit Bewegungseffekt. Sie treten abrupt auf und können alle Körperregionen erfassen, sich aber auch von einer Körperregion zur anderen ausbreiten. Wichtigste Form der Chorea ist die hereditäre Chorea Huntington, die im Längsschnitt nahezu immer ein gemischt neurologisch-psychiatrisches Gepräge hat. Chorea ist auch Symptom weiterer neurodegenerativer oder anderer seltener und dann meist erblicher (Stoffwechsel-)Erkrankungen. Sie tritt zudem symptomatisch bei unterschiedlichen Grundkrankheiten auf. Chorea ist in diesen Fällen medikamentös meist befriedigend zu kontrollieren.
Morbus Wilson
Authors: Günther  , Hermann  , Kühn  , Wagner
Published: January 2007

Der Morbus Wilson ist eine autosomal-rezessiv vererbte Kupferspeichererkrankung. Eine defekte biliäre Kupferexkretion führt zur Ablagerung des Metalls in Leber, Gehirn und anderen Organen mit vielgestaltiger Manifestation. Die Einteilung der Verlaufsformen orientiert sich an der variablen hepatischen und extrapyramidal-motorischen Symptomatik. Die Diagnostik erfolgt interdisziplinär und zielt auf den Nachweis des gestörten Kupfermetabolismus ab. Neben laborchemischen Untersuchungen, einer augenärztlichen Vorstellung und Leberbiopsie können bildgebende Verfahren, neurophysiologische Methoden sowie ein Radiokupfertest hilfreich sein. Für die Prognose sind rechtzeitige Diagnosestellung, konsequente medikamentöse Behandlung, die abhängig vom Stadium mit einem Chelatbildner oder Zinkpräparat erfolgen kann und eine regelmäßige Therapiekontrolle entscheidend. Für medikamentös nicht beherrschbare Fälle stellt die Lebertransplantation eine Therapiealternative dar.
Neuroendokrine Tumoren des Gastrointestinaltraktes
Authors: Arnold
Published: January 2007

Neuroendokrine Tumoren (NET) des Gastrointestinaltraktes sind selten auftretende Erkrankungen. Sie bilden 0.5–1% aller malignen Tumoren des Menschen. NET des Gastrointestinaltraktes werden nach ihrer endokrinen Aktivität in klinisch funktionelle oder nicht-funktionelle Tumoren eingeteilt. Eine weitere Einteilung erfolgt nach ihrer Lokalisation und embryologischen Abstammung in Vorder-, Mittel- und Hinterdarm-Tumoren. Klinisch pathologisch werden NET des Gastrointestinaltraktes nach der WHO-Klassifikation aus dem Jahre 2000 eingeteilt, deren Klassifikationskriterien auf der Tumorgrösse, Angioinvasion und dem Proliferationsmarker Ki-67 beruhen. NET des Gastrointestinaltraktes werden oft erst in fortgeschrittenen Tumorstadien aufgrund ihrer Symptomarmut diagnostiziert bzw. bei Auftreten von Beschwerden im Rahmen eines Hypersekretionssyndromes. Die Diagnostik stützt sich bei den endokrin aktiven Tumoren auf den Nachweis der unkontrolliert sezernierten Hormone sowie den von den meisten Tumoren gebildeten Tumormarker Chromogranin A im Serum. Weiterhin stehen Schnittbildverfahren zum Nachweis von Organmetastasen sowie endoskopische Verfahren einschliesslich der Endosonographie zum Nachweis des Primärtumors zur Verfügung. Einen besondereren Stellenwert besitzt die Somatostatin-Rezeptor Szintigraphie, die mit hoher Sensitivität Primärtumoren und Metastasen nachweisen kann. Primärziel der Therapie ist die Kuration durch chirurgische Verfahren. Da viele Tumoren jedoch erst in fortgeschrittenen Stadien diagnostiziert werden, stehen medikamentöse Therapiemassnahmen im Vordergrund. Hierzu zählen insbesondere biologische Therapieverfahren mit Somatostatinanaloga und/oder α-Interferon. Zur symptomatischen medikamentösen Therapie stehen weiterhin Diazoxid beim Insulinom sowie Protonenpumpenhemmer beim Gastrinom zur Verfügung. Als weitere Therapieoption kommen chemotherapeutische Massnahmen sowie Verfahren zur Tumorreduktion in Frage. Zuletzt hat die Radioligandentherapie mit 90Y-DOTA Octreotid bzw. 177Lu-DOTA Octreotate für Aufsehen gesorgt. Dieses Verfahren wird derzeit jedoch noch in Studien erprobt. Insgesamt sollte die Behandlung von NET des Gastrointestinaltraktes interdisziplinär zwischen Internisten, Chirurgen und Nuklearmedizinern individuell festgelegt werden. Der folgende Beitrag gibt einen Überblick über Epidemiologie, Klinik, Diagnostik und Therapie von NET des Gastrointestinaltraktes.
Gastrointestinale Stromatumoren (GIST)
Authors: Hohenberger
Published: January 2007

Gastrointestinale Stromatumoren (GIST) sind durch eine aktivierende Mutation im c-kit Rezeptor (CD117) gekennzeichnete, abdominale Sarkomentität. Die R0-Resektion des Primärtumors, der regelhaft keine Lymphknotenmetastasen aufweist, mit tumorfreien Rändern ist Ziel der Primärbehandlung. Die metastatische Tumorausbreitung erfolgt fast ausschliesslich peritoneal und hepatisch. Bei Tumoren im metastasierten Stadium ist eine Behandlung mit dem Tyrosinkinase-Inhibitor Imatinib-mesylat (Glivec®) indiziert und mit Ansprechraten über 70% sehr effektiv. Eine systemische Chemotherapie oder Strahlentherapie ist unwirksam. Patienten, die zur Resektion eines GIST einer multiviszeralen Operation bedürfen, erleiden rasch ein Tumorrezidiv, und können von einer präoperativen Therapie mit Imatinib-mesylat profitieren. Primärtumoren werden in vier Risikogruppen hinsichtlich ihres malignen Potenzials eingeteilt. Für Patienten der Hochrisikogruppe werden derzeit international Studien zum Nutzen einer adjuvanten Therapie vorgenommen. Patienten mit initial metastasiertem oder lokal fortgeschrittenem GIST, die unter Imatinib eine Tumorremission erzielen, sollen im Hinblick auf eine Resektion des Residualtumors evaluiert werden. In Einzelfällen kann es sinnvoll sein, singuläre, progrediente Metastasen zu resezieren, vor allem wenn weitere medikamentös kontrollierte Metastasen vorliegen.
A new theory on tidal currents rotation
Authors: Carbajal Noel , Gaviño Juan H.
Published: January 2007

Applying the linearized equations of motion, projection on the complex plane and a representation of the velocity vector and the forcing sea surface elevation gradient in function of the eigenvectors of the homogeneous system, we developed a theory that explains essential properties of tidal currents. We found the existence of a fundamental vector which we call sense of rotation s. The ellipticity, until now defined as a scalar quantity, results from the theory as a vector ɛ, normalized from s. ɛ is a measure of the eccentricity and sense of rotation of tidal ellipses and has some properties that are similar to those of the angular velocity. We derived an expression for the major and minor semi‐axis in function of physical properties and characteristics of amphidromic systems. These and other results of the theory allow the analysis of important aspects of tidal currents.
Thermal infrared reflectance and emission spectroscopy of quartzofeldspathic glasses
Authors: Byrnes Jeffrey M. , Ramsey Michael S. , King Penelope L. , Lee Rachel J.
Published: January 2007

This investigation seeks to better understand the thermal infrared (TIR) spectral characteristics of naturally‐occurring amorphous materials through laboratory synthesis and analysis of glasses. Because spectra of glass phases differ markedly from their mineral counterparts, examination of glasses is important to accurately determine the composition of amorphous surface materials using remote sensing datasets. Quantitatively characterizing TIR (5–25 μm) spectral changes that accompany structural changes between glasses and mineral crystals provides the means to understand natural glasses on Earth and Mars. A suite of glasses with compositions analogous to common terrestrial volcanic glasses was created and analyzed using TIR reflectance and emission techniques. Documented spectral characteristics provide a basis for comparison with TIR spectra of other amorphous materials (glasses, clays, etc.). Our results provide the means to better detect and characterize glasses associated with terrestrial volcanoes, as well as contribute toward understanding the nature of amorphous silicates detected on Mars.
Atomic oxygen photoionization rates computed with high resolution cross sections and solar fluxes
Authors: Meier R. R. , McLaughlin Brendan M. , Warren H. P. , Bishop James
Published: January 2007

Accurate knowledge of photoionization rates is fundamental for the study and understanding of gases in the solar system. Past calculations of the photoionization rates of atmospheric gases lack the spectral resolution to accommodate highly structured autoionization features in the photoionization cross section. A new theoretical model of the atomic oxygen photoionization cross section combined with a new solar minimum spectral irradiance model enables calculations at very high spectral resolution (0.001 nm). Our analysis of unattenuated photoionization rates reveals no strong coincidences among myriad bright solar emission lines and autoionization lines in the cross section. However, deeper in the terrestrial atmosphere, opacity effects are significant and the need for high spectral accuracy becomes increasingly important. In our solar minimum example, factor of 3 errors occur when the lower thermospheric photoionization rate of atomic oxygen is computed at 1 nm spectral resolution for both the cross section and solar flux.
Differences between the abilities of tegaserod and motilin receptor agonists to stimulate gastric motilityin vitro
Authors: Jarvie E M , North Laidler V J , Corcoran S , Bassil A , Sanger G J
Published: January 2007

Background and purpose:

Motilin or 5‐HT4receptor agonists stimulate gastrointestinal motility. Differences in activity are suggested but direct comparisons are few. A method was devised to directly compare the gastric prokinetic activities of motilin, the motilin receptor agonist, erythromycin, and the 5‐HT4receptor agonist, tegaserod.

Experimental approach:

Gastric prokinetic‐like activity was assessed by measuring the ability to facilitate cholinergically‐mediated contractions evoked by electrical field stimulation (EFS) in rabbit isolated stomach. Comparisons were made between potency, maximal activity and duration of responses.

Key results:

Rabbit motilin (r.motilin) 0.003–0.3μM, [Nle13]motilin 0.003–0.3μM, erythromycin 0.3–10μM and tegaserod 0.1–10μM caused concentration – dependent potentiation of EFS‐evoked contractions. The potency ranking was r.motilin = [Nle13]motilin > tegaserod > erythromycin. The Emaxranking was r.motilin = [Nle13]motilin = erythromycin > tegaserod. Responses to r.motilin and [Nle13]motilin faded rapidly (t1/29 and 11 min, respectively) whereas those to erythromycin and tegaserod were maintained longer (t1/224 and 28 min). The difference did not appear to be due to peptide degradation. A second application of [Nle13]motilin was excitatory after 60 min contact and fade of the initial response (responses to 0.03 and 0.1μM [Nle13]motilin were not different from those caused by the first application).

Conclusions and implications:

Prokinetic‐like activities of the 5‐HT4agonist tegaserod and the motilin receptor agonists were compared by measuring changes in cholinergically‐mediated contractions. This novel approach highlighted important differences between classes (greater Emaxof motilin, compared with tegaserod) and for the first time, within each class (short t1/2for motilin, compared with erythromycin).

British Journal of Pharmacology(2007)150, 455–462. doi:10.1038/sj.bjp.0707118
Water adsorption in ion-bearing nanopores
Authors: Lakatos G. , Patey G. N.
Published: January 2007

Grand canonical Monte Carlo simulations are used to examine the adsorption of water into cylindrical nanopores containing single ions. The isotherms for water adsorbing into nanopores with radii of 0.44, 0.54, 0.64, and 0.74nm and containing Na+, K+, Ca2+, Cl−, or F− at 298K are computed. In all cases the nanopores are found to fill at reservoir chemical potentials below the chemical potential of saturated water vapor at 298K. The threshold chemical potential is found to be sensitive to both the size of the channel and the ion species, with the anion-bearing pores filling at lower chemical potentials. Additionally, the filling threshold chemical potential is found to decrease as the radius of the pores is decreased. Pores with K+ and Cl− are compared, and the Cl− pores are found to exhibit higher water densities in the filled states and a more energetically favorable water structure while yielding lower per particle entropies. Sample simulation configurations are also examined and indicate that at low chemical potentials, the adsorbed water forms a cluster around the ion. Finally, the influence of the choice of water model on the adsorption isotherms is examined.
Dependence of nanomechanical modification of polymers on plasma-induced cross-linking
Authors: Tajima S. , Komvopoulos K.
Published: January 2007

The nanomechanical properties of low-density polyethylene (LDPE) modified by inductively coupled, radio-frequency Ar plasma were investigated by surface force microscopy. The polymer surface was modified under plasma conditions of different ion energy fluences and radiation intensities obtained by varying the sample distance from the plasma power source. Nanoindentation results of the surface stiffness versus maximum penetration depth did not reveal discernible differences between untreated and plasma-treated LDPE, presumably due to the small thickness of the modified surface layer that resulted in a substrate effect. On the contrary, nanoscratching experiments demonstrated a significant increase in the surface shear resistance of plasma-modified LDPE due to chain cross-linking. These experiments revealed an enhancement of cross-linking with increasing ion energy fluence and radiation intensity, and a tip size effect on the friction force and dominant friction mechanisms (adhesion, plowing, and microcutting). In addition, LDPE samples with a LiF crystal shield were exposed to identical plasma conditions to determine the role of vacuum ultraviolet (VUV) and ultraviolet (UV) radiation in the cross-linking process. The cross-linked layer of plasma-treated LDPE exhibited much higher shear strength than that of VUV/UV-treated LDPE. Plasma-induced surface modification of the nanomechanical properties of LDPE is interpreted in the context of molecular models of the untreated and cross-linked polymer surfaces derived from experimental findings.
Admittance spectroscopy of CdTe∕CdS solar cells subjected to varied nitric-phosphoric etching conditions
Authors: Proskuryakov Y. Y. , Durose K. , Taele B. M. , Welch G. P. , Oelting S.
Published: January 2007

In this work we investigate the electric and structural properties of CdTe∕CdS solar cells subjected to a nitric-phosphoric (NP) acid etching procedure, employed for the formation of a Te-rich layer before back contacting. The etching time is used as the only variable parameter in the study, while admittance spectroscopy is employed for the characterization of the cells’ electric properties as well as for the analysis of the defect energy levels. Particular attention was also given to the characteristics of unetched devices and it is shown that despite the larger height of back-contact barrier such samples show well defined admittance spectra, as well as allow for extraction of as much as five defect levels in the range of 0.08–0.9eV above the valence band. In contrast, admittance characteristics of the etched samples show a decrease of the number of the detectable trap levels with increasing etching time. (Hence it is usual for only one or two trap levels to be reported in the literature for finished devices.) The latter leads to the anomalous Arrhenius energy plots as well as the breakdown of low-frequency capacitance characteristics for samples etched with times larger than 30s. The observed effects are attributed to physical thinning of the cells, the etching out of grain boundaries, and the tellurium enrichment of the CdTe surface by NP etching. We also perform analysis of the back-contact barrier height as extracted from dark I-V measurements at different temperatures. The dependence of this barrier height on NP etching time is compared with that of conversion efficiency, from which conclusions are drawn about both positive and negative effects of the nitric-phosphoric etch.