bluuebunny/crossref_metadata_2025 huggingface dataset:
Co-stationarity of the ground model
Authors: Dobrinen Natasha , Friedman Sy-David
Published: December 2007

This paper investigates when it is possible for a partial ordering ℙ to force Pk(Λ)\V to be stationary in Vℙ. It follows from a result of Gitik that whenever ℙ adds a new real, then Pk(Λ)\V is stationary in Vℙ for each regular uncountable cardinal κ in Vℙ and all cardinals λ ≥ κ in Vℙ [4], However, a covering theorem of Magidor implies that when no new ω-sequences are added, large cardinals become necessary [7]. The following is equiconsistent with a proper class of ω1-Erdős cardinals: If ℙ is ℵ1-Cohen forcing, then Pk(Λ)\V is stationary in Vℙ, for all regular κ ≥ ℵ2and all λ ≩ κ. The following is equiconsistent with an ω1-Erdős cardinal: If ℙ is ℵ1-Cohen forcing, then is stationary in Vℙ. The following is equiconsistent with κ measurable cardinals: If ℙ is κ-Cohen forcing, then is stationary in Vℙ.
Lowness and nullsets
Authors: Downey Rod , Nies Andre , Weber Rebecca , Yu Liang
Published: December 2007

We prove that there exists a noncomputable c.e. real which is low for weak 2-randomness, a definition of randomness due to Kurtz, and that all reals which are low for weak 2-randomness are low for Martin-Löf randomness.
Menger's covering property and groupwise density
Authors: Tsaban Boaz , Zdomskyy Lyubomyr
Published: December 2007

We establish a surprising connection between Menger's classical covering property and Blass-Laflamme's modern combinatorial notion of groupwise density. This connection implies a short proof of the groupwise density bound on the additivity number for Menger's property.
Epsilon substitution method for -FIX
Authors: Arai Toshiyasu
Published: December 2007

In this paper we formulate epsilon substitution method for a theory -FIX for nonmonotonic inductive definitions. Then we give a termination proof of the H-processes based on Ackermann [1].
Predicate Logics of Constructive Arithmetical Theories
Authors: Visser Albert
Published: December 2007

In this paper, we show that the predicate logics of consistent extensions of Heyting's Arithmetic plus Church's Thesis with uniqueness condition are complete. Similarly, we show that the predicate logic of HA*. i.e. Heyting's Arithmetic plus the Completeness Principle (for HA*) is complete. These results extend the known results due to Valery Plisko. To prove the results we adapt Plisko's method to use Tennenbaum's Theorem to prove ‘categoricity of interpretations’ under certain assumptions.
Asymptotic classes of finite structures
Authors: Elwes Richard
Published: December 2007

In this paper we consider classes of finite structures where we have good control over the sizes of the definable sets. The motivating example is the class of finite fields: it was shown in [1] that for any formulain the language of rings, there are finitely many pairs (d,μ) ∈ω×Q>0so that in any finite fieldFand for any ā ∈Fmthe size |ø(Fn,ā)| is “approximately”μ|F|d. Essentially this is a generalisation of the classical Lang-Weil estimates from the category of varieties to that of the first-order-definable sets.
Δ3O-determinacy, comprehension and induction
Authors: Medsalem Medyahya Ould , Tanaka Kazuyuki
Published: December 2007

We show that each of and proves -Det and that neither nor can be dropped. We also show that neither nor proves -Det. Moreover, we prove that none of and is provable in
Sublocales in formal topology
Authors: Vickers Steven
Published: December 2007

The paper studies how the localic notion of sublocale transfers to formal topology. For any formal topology (not necessarily with positivity predicate) we define a sublocale to be a cover relation that includes that of the formal topology. The family of sublocales has set-indexed joins. For each set of base elements there are corresponding open and closed sublocales, boolean complements of each other. They generate a boolean algebra amongst the sublocales. In the case of an inductively generated formal topology, the collection of inductively generated sublocales has coframe structure.

Overt sublocales and weakly closed sublocales are described, and related via a new notion of “rest closed” sublocale to the binary positivity predicate. Overt, weakly closed sublocales of an inductively generated formal topology are in bijection with “lower powerpoints”, arising from the impredicative theory of the lower powerlocale.

Compact sublocales and fitted sublocales are described. Compact fitted sublocales of an inductively generated formal topology are in bijection with “upper powerpoints”, arising from the impredicative theory of the upper powerlocale.
Burgess’PVis Robinson’sQ
Authors: Ganea Mihai
Published: December 2007

In [2] John Burgess describes predicative versions of Frege's logic and poses the problem of finding their exact arithmetical strength. I prove here thatPV, the simplest such theory, is equivalent to Robinson's arithmetical theoryQ.
The Case of H.S.: The Ethics of Reporting Alcohol Dependence in a Bus Driver
Authors: Karol David E. , Schuermeyer Isabel N. , Brooker Craig A.
Published: December 2007

The physician's duty to preserve patient confidentiality is challenged when doing so may endanger third parties. We present the case of a bus driver whose alcohol dependence raised concerns of a risk not only to his own health and safety, but to public safety as well. We first examine the legal and ethical obligations to report his alcohol use to his employer and then stress the importance of weighing the potential harm of violating patient-physician confidentiality against the severity of risk to the general public.
Invisible Contributions in Families with Children and Adults with Intellectual Disabilities
Authors: Grant Gordon
Published: December 2007

For many years there has been an underlying pathology within the literature about families with children and adults with intellectual disabilities (Helff & Glidden, 1998). This literature has emphasized stress and burden, incapacity and dependency, leading to negative stereotyping of families in this context. Over the last 2 decades research has led to some important reconceptualizations of how families approach their caring, affording an improved understanding of how they deploy strengths and resources, and who benefits. This paper reviews this thinking, arguing that it provides a suitable context for understanding the scope and form of family caregiving contributions that are less visible, and therefore less recognized. An attempt is therefore made to chart invisible contributions. It is suggested that invisible contributions have implications for thinking about human and social capital (Putnam, 2000) as well as for practice in supporting families.
Cultural Predictors of Caregiving Burden of Chinese-Canadian Family Caregivers
Authors: Lai Daniel W.L.
Published: December 2007

The growth of research knowledge on culturally diverse family caregivers for the aging population lags behind the increase of culturally diverse populations in Canada. This study examines the effects of culture, as manifested through cultural variables, on the caregiving burden of family caregivers in a Chinese-Canadian community. A random sample of 339 Chinese-Canadian caregivers for elderly relatives completed a telephone survey. Results of hierarchical stepwise multiple regression analysis reported the predicting effects of culture-related variables on caregiving burden. The findings indicated that being an immigrant, having a Western or non-Western religion as compared to having no religion, and having a lower level of filial piety, predicted a higher level of caregiving burden. Chinese tradition does not exempt the caregivers from being burdened. Policies and practices should address the needs of family caregivers according to the intra-cultural variations identified in this study.
Anisotropic radio-wave scattering from englacial water regimes, Mýrdalsjökull, Iceland
Authors: Matsuoka Kenichi , Thorsteinsson Throstur , Björnsson Helgi , Waddington Edwin D.
Published: December 2007

Colinear-polarized 5 MHz radar profiling data were obtained on Mýrdalsjökull, a temperate glacier in Iceland. Radar transects, and therefore polarization planes, were aligned approximately parallel, transverse and oblique to the ice flow direction. Echoes from the shallower half to two-thirds of the ice were 10–20dB stronger on the oblique and longitudinal transects than those on the transverse transects. Anisotropy as a function of depth is clearly seen at the sites where the transects cross. Strong scattering on longitudinal transects apparently caused extinction of a radar-reflecting layer that was continuously profiled on the transverse transects. A radio-wave scattering model shows that scattering from a longitudinal water-filled conduit parallel to the glacier surface can explain the observed azimuthal variations of the echo. We conclude that low-frequency (~MHz) radio waves can help to characterize englacial water regimes.
Moving conventional workers compensation systems toward conflict resolution to provide better results
Authors: Posthuma Richard A.
Published: December 2007

Richard A. Posthuma, of El Paso, Texas, provides the fundamentals of installing best conflict resolution practices into a workers' comp scheme to yield lower costs and better employee relations
Structural Selection in G‐Quartet‐Based Hydrogels and Controlled Release of Bioactive Molecules
Authors: Sreenivasachary Nampally , Lehn Jean‐Marie
Published: December 2007

A guanosine‐5′‐hydrazide can entrap biologically interesting molecules such as acyclovir, vitamin C, and vancomycin into its hydrogel network. Controlled release of these molecules was monitored by 1H NMR spectroscopy. The hydrazide may potentially form mixed G–G quartets with analogous compounds containing a guanine group. 1H NMR spectroscopy was used to study the inclusion of various guanine derivatives into the hydrogel. The structural selectivity was found to depend strongly on both the shape and the charge of the additive and may arise from the strong cohesion of the supramolecular architecture of the gel and the resulting resistance to perturbation by foreign bodies. Hydrogels thus offer a promising medium for highly selective, controlled release of bioactive substances.
Regression with multiple regressor arrays
Authors: Plaehn Dave C. , Lundahl David S.
Published: December 2007

Extension of standard regression to the case of multiple regressor arrays is given via the Kronecker product. The method is illustrated using ordinary least squares regression (OLS) as well as the latent variable (LV) methods principal component regression (PCR) and partial least squares regression (PLS). Denoting the method applied to PLS as mrPLS, the latter was shown to explain as much or more variance for the first LV relative to the comparable L‐partial least squares regression (L‐PLS) model. The same relationship holds when mrPLS is compared to PLS or n‐way partial least squares (N‐PLS) and the response array is 2‐way or 3‐way, respectively, where the regressor array corresponding to the first mode of the response array is 2‐way and the second mode regressor array is an identity matrix. In a comparison with N‐PLS using fragrance data, mrPLS proved superior in a validation sense when model selection was used. Though the focus is on 2‐way regressor arrays, the method can be applied to n‐way regressors via N‐PLS. Copyright © 2007 John Wiley & Sons, Ltd.
Expression of calcium channel CaV1.3 in cat spinal cord: Light and electron microscopic immunohistochemical study
Authors: Zhang Mengliang , Møller Morten , Broman Jonas , Sukiasyan Natalya , Wienecke Jacob , Hultborn Hans
Published: December 2007

In spinal neurons, plateau potentials serve to amplify neuronal input signals. To a large extent, the underlying persistent inward current is mediated by a subtype of the L‐type calcium channel (CaV1.3). In the present investigation, we have studied its distribution and cellular localization in the cat spinal cord by light and electron microscopic immunohistochemistry. The results show that CaV1.3‐like immunoreactivity is widely distributed in all segments of the spinal cord but that the distribution in the different laminae of the spinal gray matter varies, with the highest density of labeled neurons in lamina IX and the lowest in lamina II. The labeling intensity was highest in neuronal somata, but a certain length of the proximal dendrite was also labeled. Some neuronal groups exhibited a particularly dense labeling; these include the lateral motoneuronal group in the cervical and the lumbar enlargements and the phrenic nucleus in cervical, Clarke's nucleus in lower thoracic and upper lumbar, and Onuf's nucleus in upper sacral segments. At the ultrastructural level, CaV1.3‐immunoreactive products were found in neuronal somata and dendrites of different sizes. In the soma, they were predominantly associated with the rough endoplasmic reticulum but some also with the plasma membrane. In dendrites, they were associated with both intracellular organelles, including microtubules and microchondria, and the plasma membrane. These results indicate that significant proportions of the neurons in cat spinal cord, including projection neurons, interneurons, and motoneurons, are endowed with ion channels that subserve persistent inward currents and act to amplify synaptic input signals. J. Comp. Neurol. 507:1109–1127, 2008. © 2007 Wiley‐Liss, Inc.
Familiality and heritability of binge eating disorder: Results of a case‐control family study and a twin study
Authors: Javaras Kristin N. , Laird Nan M. , Reichborn‐Kjennerud Ted , Bulik Cynthia M. , Pope Harrison G. , Hudson James I.
Published: December 2007

Objective:

To estimate the familiality and heritability of binge eating disorder (BED).

Method:

We used a new ACE structural equation model to estimate heritability from a case‐control family study of BED conducted in the Boston area. The sample consisted of 150 overweight/obese probands with lifetime BED by DSM‐IV criteria, 150 overweight/obese probands without lifetime BED, and 888 of their first‐degree relatives. We compared our findings with those from a study of binge eating (in the absence of compensatory behaviors) among 7,831 Norwegian twins.

Results:

The prevalence of BED differed by sex and by age. In the case‐control family study, BED was found to aggregate in families, and heritability was estimated as 57% (CI: 30–77%). Including shared environment did not substantially improve the model's fit, nor did allowing sex‐specific heritability. Findings from the twin study were similar.

Conclusion:

BED appears to aggregate in families and have a significant genetic component. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord, 2008
An empirical study of the typology of bulimic symptoms in young Portuguese women
Authors: Pinheiro Andrea Poyastro , Bulik Cynthia M. , Sullivan Patrick F. , Machado Paulo P. P.
Published: December 2007

Objective:

To investigate whether clusters of bulimic symptoms exist in a community sample of young Portuguese women.

Method:

A total of 2028 females, aged 12–23 years, completed the Eating Disorder Examination Questionnaire (EDE‐Q). Latent class analysis was applied to the seven bulimic symptoms, age, and body mass index.

Results:

The selected 4‐class solution yielded a “healthy” class, reporting minimal binge eating and purging behaviors. A “binge eating” class, resembled binge eating disorder. A “purging” class had infrequent binge eating, but frequent compensatory behaviors. Finally, in a “classic bulimia nervosa” class, binge eating episodes were reported by 95% of participants, and compensatory behaviors were frequently endorsed. EDE ‐Q global and subscale scores differed across all latent classes.

Conclusion:

In the community, three natural patterns exist: binge eating plus compensatory behaviors, binge eating only, and purging in the absence of binge eating. These results have implications for future revisions of eating disorders nosology. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord, 2008
Implications of REACH for developing countries
Authors: Ackerman Frank , Stanton Elizabeth A. , Roach Brian , Andersson Anne‐Sofie
Published: December 2007

The new European Union (EU) chemicals regulation, the Registration, Evaluation and Authorisation of Chemicals, or REACH, went into effect in 2007. In the extensive advance discussion of the expected impacts of REACH, questions were raised about the effects of this new chemical policy on developing countries. In particular, will it harm the economies of the group of African, Caribbean and Pacific (ACP) countries that historically have been connected to Europe? We found, in brief, that there are only limited, isolated cases where REACH could be problematical for ACP exporters. Almost all ACP exports subject to REACH face insignificant obstacles from the new regulation. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Structural Aspects of the Growth Mechanism of Copper Nanoparticles Inside Apoferritin
Authors: Ceolín Marcelo , Gálvez Natividad , Sánchez Purificación , Fernández Belén , Domínguez‐Vera José M.
Published: December 2007

It is well known that some of the metal ions remain bound to apoferritin when incubating apoferritin with metal ions. In this study a structural insight, from X‐ray absorption spectroscopy (XAS) and small angle X‐ray scattering (SAXS) experiments, into the mechanism of inorganic core formation is presented. The results indicate that, in the case of CuII at pH 8, the metal ions bound to apoferritin are in fact CuII oxide/hydroxide. This CuII species does not react with the CuII‐specific TTMAPP, traditionally used to detect CuII, because TTMAPP is too large to penetrate the apoferritin channel and interact with the metal ions. EXAFS results suggest that the CuII precursor can be described as an amorphous network of oxygen/hydroxide‐coordinating polyhedra surrounding the copper ions. XAS results demonstrate that this CuII‐oxide/hydroxide species is completely converted into zero‐valent Cu nanoparticles when treated with NaBH4. Furthermore, a structural model for the final Cu0 nanoparticle is offered.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Development of a Korean version of the behavior rating scale for dementia (BRSD‐K)
Authors: Youn Jong Chul , Lee Dong Young , Lee Jung Hie , Kim Ki Woong , Jhoo Jin Hyeong , Choo Il Han , Paek Yong Su , Jeon Yong Ho , Seo Kwan Woo , Woo Jong Inn
Published: December 2007

Objective

The purpose of this study was to develop a Korean version of the behavior rating scale for dementia (BRSD‐K) for evaluating behavioral and psychological symptoms of dementia.

Methods

The BRSD‐K was administered to the informants of 268 subjects with dementia. Internal, inter‐rater and test–retest reliabilities were tested. To evaluate construct validity, exploratory factor analysis was performed. To evaluate concurrent validity, Pearson correlation coefficients between BRSD‐K scores and the corresponding scores of the Korean version of the neuropsychiatric inventory (NPI‐K) were calculated.

Results

BRSD‐K demonstrated substantially high levels of reliabilities. Factor analysis identified seven factors, i.e. depressive symptoms, irritability/aggression, psychotic symptoms, behavioral dysregulations, sleep disturbance, inertia, and appetite. Correlations between BRSD‐K and corresponding NPI‐K scores were statistically significant (p < 0.05).

Conclusions

BRSD‐K was found to be a reliable and valid instrument for evaluating BPSD. Copyright © 2007 John Wiley & Sons, Ltd.
Neural substrates of phonological and lexicosemantic representations in Alzheimer's disease
Authors: Peters Frederic , Majerus Steve , Collette Fabienne , Degueldre Christian , Fiore Guy Del , Laureys Steven , Moonen Gustave , Salmon Eric
Published: December 2007

The language profile of patients suffering from Alzheimer's disease (AD) is characterized not only by lexicosemantic impairments but also by phonological deficits, as shown by an increasing number of neuropsychological studies. This study explored the functional neural correlates underlying phonological and lexicosemantic processing in AD. Using H215O PET functional brain imaging, a group of mild to moderate AD patients and a group of age‐matched controls were asked to repeat four types of verbal stimuli: words, wordlike nonwords (WL+), non‐wordlike nonwords (WL−) and simple vowels. The comparison between the different conditions allowed us to determine brain activation preferentially associated with lexicosemantic or phonological levels of language representations. When repeating words, AD patients showed decreased activity in the left temporo‐parietal and inferior frontal regions relative to controls, consistent with distorted lexicosemantic representations. Brain activity was abnormally increased in the right superior temporal area during word repetition, a region more commonly associated with perceptual‐phonological processing. During repetition of WL+ and WL− nonwords, AD patients showed decreased activity in the middle part of the superior temporal gyrus, presumably associated with sublexical phonological information; at the same time, AD patients showed larger activation than controls in the inferior temporal gyrus, typically associated with lexicosemantic levels of representation. Overall, the results suggest that AD patients use altered pathways to process phonological and lexicosemantic information, possibly related to a progressive loss of specialization of phonological and lexicosemantic neural networks. Hum Brain Mapp 2009. © 2007 Wiley‐Liss, Inc.
Neuroendocrine pathways in benzodiazepine dependence: new targets for research and therapy
Authors: Heberlein Annemarie , Bleich Stefan , Kornhuber Johannes , Hillemacher Thomas
Published: December 2007

Benzodiazepines are known to modulate the activity of the hypothalamo‐pituitary‐adrenocortical (HPA) axis by antagonizing the effects of corticotropin‐releasing factor (CRH). Besides regulating the HPA axis CRH evolves properties of a neurotransmitter in the limbic system that is closely involved in the delivery of the emotional consequences of the stress response. At a superordinated level Neuropeptide Y (NPY) and Cholecystokinin (CCK) affect the release of CRH and modulate thereby the intensity of the physiological stress response. Benzodiazepine treatment interferes not only with the release of CRH but also with the release of NPY and CCK. Alterations in the intracortical ratio of NPY, CCK and CRH are correlated with behavioural changes like increased respectively decreased anxiety and subsequent alterations in the activity of the HPA axis. Recent research offers the possibility that the alterations of plasma levels of these neuropeptides are not only a secondary phenomenon due to drug intake, but that low levels of those neuropeptides that modulate anxiety and fear can possibly explain addiction to substances that counterbalance these deficits. Depending on the available results possible implications of NPY and CCK on benzodiazepine addiction and withdrawal symptoms are reviewed, thereby providing topics for further research. Copyright © 2007 John Wiley & Sons, Ltd.
Improved peripheral blood stem cell collection following plasma exchange in a patient with elevated viscosity and coagulopathy
Authors: Alex Jessie , Erickson Yasuko O. , Schlueter Annette J.
Published: December 2007

We report a case of improved CD34+ cell yields from peripheral blood stem cell (PBSC) collection following therapeutic plasma exchange (TPE) in a patient with elevated viscosity and coagulopathy. The patient was a 46‐year‐old male diagnosed with IgM lambda multiple myeloma that was largely unresponsive to standard chemotherapy. He had coagulopathy due to lymphoproliferative disease‐associated acquired von Willebrand Factor (vWF) deficiency. The patient underwent two rounds of PBSC collections over 3 consecutive weeks (five total collections) prior to planned tandem transplant for multiple myeloma. Both rounds resulted in poor collections due to processing difficulties. It was decided to perform three TPEs daily immediately prior to attempting additional PBSC collections, to treat the patient's elevated viscosity and thereby potentially improve the efficiency of collections. Immediately following the three TPEs, two additional PBSC collections resulted in sufficient CD34+ cells to proceed to transplant. Lower IgM and/or viscosity levels present after the three TPEs likely permitted successful collection of stem cells. J. Clin. Apheresis, 2007. © 2007 Wiley‐Liss, Inc.
Unsuspected gallbladder cancer diagnosed during or after laparoscopic cholecystectomy
Authors: Kwon A‐Hon , Imamura Atsushi , Kitade Hiroaki , Kamiyama Yasuo
Published: December 2007

Background

The long‐term prognosis of laparoscopic cholecystectomy (LC) for patients with unsuspected gallbladder carcinoma (GBC) remains unclear. We investigated retrospectively the role of examination of frozen sections and the prognosis of patients with unsuspected GBC detected during or after LC.

Methods

LC was performed on 1,793 consecutive patients. If a suspicious lesion was found, intraoperative frozen section examination was performed.

Results

Of all these patients, 38 (2.1%) were histopathologically diagnosed as having a GBC during (28) or after LC (10). The tumor stages of the 28 diagnosed during LC were: pT1a (17), pT1b (2), pT2 (8), and pT3 (1). The sensitivity and specificity of intraoperative frozen section examination were 90 and 100%, respectively. On the other hand, those 10 cases diagnosed after LC had pT1a (1) and pT2 (9) tumors. Survival rates were not significantly affected by whether the patient was diagnosed with GBC during or after LC.

Conclusions

The survival with unsuspected GBC was related to stage and it was confirmed that a carefully performed LC is adequate treatment for Stage 1A and B cancer. The LC procedure does not adversely affect the prognosis of unsuspected GBC, regardless of whether it is detected during or after LC. J. Surg. Oncol. 2008;97:241–245. © 2007 Wiley‐Liss, Inc.
Highlighting the role of the hydroxyl position on the alkyl spacer of hydroxypropyl‐β‐cyclodextrin for enantioseparation in capillary electrophoresis
Authors: Jiang Zhengjin , Thorogate Richard , Smith Norman William
Published: December 2007

This work investigates the resolving power of 2,3‐dihydroxypropyl‐β‐CD (2,3‐DHP‐β‐CD) and 3‐hydroxypropyl‐β‐CD (3‐HP‐β‐CD) as chiral mobile phase additives (CMPAs) using CE. The effects of experimental parameters (CD concentration, buffer pH, and buffer concentration) on enantiorecognition were investigated. More than 20 basic chiral drugs were resolved with satisfactory enantioselectivity. Comparison with 2‐hydroxypropyl‐β‐CD (2‐HP‐β‐CD) showed that one or both of the two new chiral selectors show enhanced enantiorecognition for several molecules with bulky substitutes, such as Zopiclone and Mianserin, however, 2‐HP‐β‐CD has higher enantiorecognition for most of the analytes. Further studies on the structures of analytes and CMPAs showed that the OH moiety on the propyl spacer plays an important role in the separation of some chiral drugs.
A new approach for the simulation of skeletal muscles using the tool of statistical mechanics
Authors: Böl M. , Reese S.
Published: December 2007

The structure of a skeletal muscle is dominated by its hierarchical architecture in which thousands of muscle fibres are arranged within a connective tissue network. The single muscle fibres consist of many force‐producing cells, known as sarcomeres. These micro biological engines are part of a motor unit and contribute to the contraction of the whole muscle. There are a lot of questions concerning the optimisation of muscle strength and agility. Standard experimental investigations are not sufficient to answer these questions because they do not supply enough information. Additionally, these methods are limited because not enough material for testing is accessible. To overcome these problems, numerical testing tools can be an adequate alternative. From the mechanical point of view the material behaviour of muscles is highly non‐linear. They undergo large deformations in space, thereby changing their shape significantly, so that geometrical nonlinearity has to be considered. Many authors use continuum‐based approaches in combination with the finite element method to describe such material behaviour. However, models of this kind require realistic constitutive relations between stress and strain which are difficult to determine in an inhomogeneous material. Furthermore, biomechanical information cannot be fully exploited in these models.

The present approach is crucially based on the use of the finite element method. The material behaviour of the muscle is split into a so‐called active and a passive part. To describe the passive part special unit cells consisting of one tetrahedral element and six truss elements have been derived. Embedded into these unit cells are further truss elements which represent bundles of muscle fibres. Depending on the discretisation it is possible to simulate the material behaviour of e.g. artery walls characterised by oriented fibres or soft tissue including only non‐oriented fibres. In summary, the present concept has the advantage that a three‐dimensional model is developed which allows us take into account many physiological processes at the micro level.
Nanocrystalline apatites in biological systems: characterisation, structure and properties
Authors: Rey C. , Combes C. , Drouet C. , Lebugle A. , Sfihi H. , Barroug A.
Published: December 2007

Nanocrystalline apatitic calcium phosphates play a crucial role in calcified tissues and biomaterials. One of the most interesting characteristics of biomimetic apatite nanocrystals is the existence of a surface hydrated layer essentially related to their formation process in solution. This hydrated layer shows specific spectroscopic characteristics. It seems to exist in its nascent state only in wet samples and is altered on drying. This surface‐hydrated layer progressively disappears as the stable apatite domains develop. The surface ions can be rapidly and reversibly exchanged in solution, mainly with selected bivalent species. The exchange reactions clearly reveal the existence of two domains: the relatively inert apatite core and the very reactive surface‐hydrated domains. The structure of the hydrated layer has been shown to be reversibly affected by the constituting ions. Such a surface layer in bone apatite nanocrystals could participate actively in homeostasis and probably other regulation processes. The specificity of biomimetic apatite nanocrystals also opens interesting possibilities in materials science. The mobility of the mineral ions on the crystal surface, for example, allows strong bonding and interactions either with other crystals or with different substrates. Inter‐crystalline interactions have been described as a “crystal fusion” process in vivo and they could be involved in the setting reaction of biomimetic calcium phosphate cements. Ceramic‐like materials using the surface interaction capabilities of the nanocrystals can be produced at very low temperature (below 200 °C). The surface‐hydrated layer could also be involved in interactions with macromolecules and polymeric materials or in the coating of implants. The ion exchange and adsorption capabilities of the nanocrystals could probably be used for drug release, offering a range of possible behaviours.
Chemistry, ultrastructure and porosity of monophasic and biphasic bone forming materials derived from marine algae
Authors: Spassova E. , Gintenreiter S. , Halwax E. , Moser D. , Schopper C. , Ewers R.
Published: December 2007

The research on bioceramics during the last decades has proved that the bioactivity of inorganic bone grafts depends fundamentally on an optimal combination of chemistry and structural porosity. This study presents a comparison of a resorbable monophasic hydroxyapatite (HA) and several newly developed resorbable biphasic hydroxyapatite – ß‐tricalcium phosphate (HA/TCP) composites both derived from naturally grown red marine algae with respect to the phase composition, microstructure and porosity. The highly porous three dimensional mineral scaffold of the native alga is maintained in the final products all investigated materials and possesses a pronounced interconnecting microporous structure. There are generally high values of specific porosity calculated for all tested materials: 1.07 cm3/g for pure phycogenic HA and between 0.65 cm3/g and 1.04 cm3/g for phycogenic biphasic HA/TCP composites with various HA/TCP ratios. The ultrastructure of the phycogenic HA/TCP composites changes significantly with the building and the increase of the ß‐TCP phase due to the bigger polyedric ß‐TCP crystals compared to the finer polycrystalline HA. Despite these structural changes the interconnected porous scaffold is kept throughout the production process. In all investigated materials the porosity is mainly based on pores with pore sizes between 1 and 10 μm in diameter, which is given by the structure of the natural alga. The specific chemistry combined with the structural porosity is decisive for the high in‐vivo bioactivity of the studied materials.
Fixation of porous calcium phosphate with expanded bone marrow cells using an autologous plasma clot
Authors: Schildhauer T.A. , Seybold D. , Geßmann J. , Muhr G. , Köller M.
Published: December 2007

Multipotent human mesenchymal stromal cells (hMSCs) are currently the most promising cell type for regenerative medicine and tissue engineering. For clinical applications with special focus on fracture repair a method to deliver in vitro‐expanded bone marrow cells to the fracture site is presented. Autologous blood plasma clotting was used to fix expanded cells and synthetic tricalcium phosphate particles. A jelly‐like but solid composite matrix was obtained which could easily be handled by the surgeon. The majority of embedded cells remained viable after the plasma gelation process, as was determined by fluorescence microscopy. Experimental cell culture over a period of 15 days showed proliferating mesenchymal stromal cells within the plasma clot.
Development of an universal affinity fusion tag (Poly‐DOPA) for immobilizing recombinant proteins on biomaterials
Authors: Jennissen H. P. , Laub M.
Published: December 2007

The covalent and non‐covalent immobilization of growth factors such as recombinant human bone morphogenetic protein 2 (rhBMP‐2) on metals and bone replacement materials in bioactive form is a recent development. Up to now the immobilization technology usually involved the chemical modification and activation of the biomaterial surface followed by attachment of the bioactive protein. Here we suggest an alternative method in which an affinity tag fused to an active protein will allow immobilization without additional chemistry. For biomaterials such as minerals, metals (titanium, steel, CoCrMo), glass ceramics, teflon and possibly bone and teeth ideal adhesion molecules would be the foot proteins (Mefps) of the mussel M. edulis which contain the rare amino acid dihydroxy phenylalanine (DOPA). Recently it could be shown by Messersmith's group that a single DOPA‐molecule can be non‐covalently bound to titanium dioxide surface with a dissociation energy of 22.2 kcal/mol (Lee, H.; Scherer, N. F.; Messersmith, P. B. Proc. Natl. Acad. Sci. U. S. A 2006, 103, 12999–13003).We therefore propose the DOPA‐tag as a general and versatile affinity tag for the immobilization of proteins on biomaterials.
Biomaterials 2006 — International Symposium — Essen, September 5–8, 2006
Authors: Jennisen H.P.
Published: December 2007

In the international symposium „Biomaterials 2006”︁ the German Society of Biomaterials (DGBM), the organizers of the XIXth „Aachen Colloquium on Biomaterials”︁ and the organizers of the 9th „International Essen Symposium on Biomaterials and Biomechanics: Fundamentals and Clinical Applications”︁ pooled forces thus bundling the potentials of the state of North Rhine‐Westphalia in the area of biomaterials to a nationwide and international initiative.

Biomaterial development is the motor of progress in implantology. In the past decades, where bulk behaviour, biocompatibility, stability and texturing of biomaterials were key areas of research and progress, one may speak of the era of „dumb materials”︁. At the turn of the century the concept, that the future of implants lies in their surface, gained acceptance and with that the evolution of „smart biomaterials”︁ (Anderson et al. 2004) began. Biocoating and functionalization of surfaces were developed with the aim of the surface directing the specific behaviour of contacting tissue cells and/or attracting precursor cells by the release of chemotactic substances. Today new functionalities are emerging such as responsive or on‐demand surfaces, allowing an on‐and‐off switching. A new focus was put on areas which have been little noticed such as ischemia and reperfusion damage due to the implantation process. Similarly nano and micro particles either therapeutically applied as delivery devices or due to wear and causing adverse reactions were discussed.

„Biomaterials 2006”︁ was an exceptional, very successful meeting with scientists from 18 countries and 140 submitted abstracts and presentations (see Jennissen, H.P. (2006) BIOmaterialien 7, 107–254) from nearly every facet of biomaterials. The present volume represents a selection of 14 key papers from the meeting which give a fine impression of the trends experienced at „Biomaterials 2006”︁ and the developments to come.
Fyn is a novel target of (−)‐epigallocatechin gallate in the inhibition of JB6 Cl41 cell transformation
Authors: He Zhiwei , Tang Faqing , Ermakova Svetlana , Li Ming , Zhao Qing , Cho Yong‐Yeon , Ma Wei‐Ya , Choi Hong‐Seok , Bode Ann M. , Yang Chung S. , Dong Zigang
Published: December 2007

The cancer preventive action of (−)‐epigallocatechin gallate (EGCG), found in green tea, is strongly supported by epidemiology and laboratory research data. However, the mechanism by which EGCG inhibits carcinogenesis and cell transformation is not clear. In this study, we report that EGCG suppressed epidermal growth factor (EGF)‐induced cell transformation in JB6 cells. We also found that EGCG inhibited EGF‐induced Fyn kinase activity and phosphorylation in vitro and in vivo. Fyn was implicated in the process because EGF‐induced JB6 cell transformation was inhibited by small interfering RNA (siRNA)‐Fyn‐JB6 cells. With an in vitro protein‐binding assay, we found that EGCG directly bound with the GST‐Fyn‐SH2 domain but not the GST‐Fyn‐SH3 domain. The Kd value for EGCG binding to the Fyn SH2 domain was 0.367 ± 0.122 µM and Bmax was 1.35 ± 0.128 nmol/mg. Compared with control JB6 Cl41 cells, EGF‐induced phosphorylation of p38 MAP kinase (p38 MAPK) (Thr180/Tyr182), ATF‐2 (Thr71) and signal transducer and activator of transcription 1 (STAT1) (Thr727) was decreased in siRNA‐Fyn‐JB6 cells. EGCG could inhibit the phosphorylation of p38 MAPK, ATF‐2, and STAT1. The DNA binding ability of AP‐1, STAT1, and ATF‐2 was also decreased in siRNA‐Fyn‐JB6 cells. Overall, these results demonstrated that EGCG interacted with Fyn and inhibited Fyn kinase activity and thereby regulated EGF‐induced cell transformation. Inhibition of Fyn kinase activity is a novel and important mechanism that may be involved in EGCG‐induced inhibition of cell transformation. © 2007 Wiley‐Liss, Inc.
Electrostatic interactions effect in the aminolysis of some β‐lactams in the presence of poly(ethyleneimine):structure‐reactivity
Authors: Arcelli Antonio , Porzi Gianni , Rinaldi Samuele , Sandri Monica
Published: December 2007

The aminolysis reaction of a series of β‐lactams in the presence of poly(ethyleneimine) (PEI) at 30°C and pH = 8.40 has been studied. The substrates investigated follow a pseudo first order rate, except two β‐lactams which show a two step consecutive reaction. Increasing the polyelectrolyte concentration, Michaelis–Menten type kinetics are been observed and for four substrates a more complex rate behaviour was verified owing to the polyelectrolyte inhibition effect. Both the binding constant K1 between polyelelectrolyte and β‐lactam and the first order rate constant of the reactive complex decomposition kcat were calculated. The substituent effect at C‐6′ or C‐7′ position of β‐lactam on the aminolysis rate does not correlate with the σI value (Taft plot). Most probably, steric and electronic effects are important, but the electrostatic ones are determining factors for the relevant acceleration attributable to both the binding phenomena and the increased reactivity of the substrate–polyelectrolyte complex. The comparison between poly(ethyleneimine) and Human Serum Albumin (HSA) is also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Facile preparation of core‐crosslinked micelles from azide‐containing thermoresponsive double hydrophilic diblock copolymer via click chemistry
Authors: Jiang Xiaoze , Zhang Jingyan , Zhou Yueming , Xu Jian , Liu Shiyong
Published: December 2007

Double hydrophilic diblock copolymer, poly(N,N‐dimethylacrylamide)‐b‐poly(N‐isopropylacrylamide‐co‐3‐azidopropylacrylamide) (PDMA‐b‐P(NIPAM‐co‐AzPAM), containing azide moieties in one of the blocks was synthesized via consecutive reversible addition‐fragmentation chain transfer polymerization. The obtained diblock copolymer molecularly dissolves in aqueous solution at room temperature, and can further supramolecularly self‐assemble into core‐shell nanoparticles consisting of thermoresponsive P(NIPAM‐co‐AzPAM) cores and water‐soluble PDMA coronas above the lower critical solution temperature of P(NIPAM‐co‐AzPAM) block. As the micelle cores contain reactive azide residues, core crosslinking can be facilely achieved upon addition of difunctional propargyl ether via click chemistry. In an alternate approach in which the PDMA‐b‐P(NIPAM‐co‐AzPAM) diblock copolymer was dissolved in a common organic solvent (DMF), the core‐crosslinked (CCL) micelles can be fabricated via “click” crosslinking upon addition of propargyl ether and subsequent dialysis against water. CCL micelles prepared by the latter approach typically possess larger sizes and broader size distributions, compared with that obtained by the former one. In both cases, the obtained (CCL) micelles possess thermoresponsive cores, and the swelling/shrinking of which can be finely tuned with temperature, rendering them as excellent candidates as intelligent drug nanocarriers. Because of the high efficiency and quite mild conditions of click reactions, we expect that this strategy can be generalized for the structural fixation of other self‐assembled nanostructures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 860–871, 2008
Reaction parameters in the RAFT mediated dispersion polymerization of styrene
Authors: Saikia Prakash J. , Lee Jung Min , Lee Kangseok , Choe Soonja
Published: December 2007

Monodisperse polystyrene (PS) particles were prepared by a living radical dispersion polymerization with a reversible addition‐fragmentation chain transfer (RAFT) agent in an ethanol medium. In the presence of RAFT agent, the effects of various reaction parameters on the characteristics of PS particles were systematically investigated. When no RAFT agent was involved, the number‐average molecular weight (Mn) of the PS particles increased from 17,800 to 30,000 g/mol, but the weight‐average diameter (Dw) decreased from 2.54 to 2.06 μm with the increase of poly(N‐vinylpyrrolidone) content from 4.0 to 16.0 wt %. No correlation between the Mn and the coefficient of variation (CV) was observed. However, when the RAFT concentration varied from 0 to 2.0 wt %, all of the conversion, Mn, Dw, CV, and polydispersity index (Mw/Mn) decreased. This indicates that the RAFT agent alters the inverse behavior between the molecular weight (MW) and particle size shown in the conventional dispersion polymerization. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 872–885, 2008
Using apparent molecular weight from SEC in controlled/living polymerization and kinetics of polymerization
Authors: Guillaneuf Yohann , Castignolles Patrice
Published: December 2007

Apparent molecular weights from size exclusion chromatography, that is molecular weights relative to standards of a nature different to that of the polymer sample being studied, are frequently used. We use calculations corresponding to realistic cases to provide guidelines for situations when, and to what extent, apparent molecular weights (MWs) can be meaningful. In controlled polymerization, we show how, without due care, use of apparent MW, could lead to the incorrect conclusion that the reaction was not controlled, whereas the true MWs would be close to theoretical values. We show here that the quality of the eluent as a solvent for the standard and the polymer sample is a good indication of the accuracy and the significance of the apparent polydispersity index. Accurate Mark–Houwink–Sakurada parameters are of limited availability, but the data about solvent quality available in handbooks or available from static light scattering measurements. Apparent Mn is of no use in controlled polymerization if simple simulations as performed in this work do not validate their use. The determination of transfer constants by the Mayo plot can be performed using apparent Mn without introducing any significant error, contrary to apparent weight‐average molecular weight Mw or apparent ln number distribution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 897–911, 2008
Study on the viscoelastic properties of the epoxy surface by means of nanodynamic mechanical analysis
Authors: Zhang Yang‐Fei , Bai Shu‐Lin , Yang Da‐Yong , Zhang Zhong , Kao‐Walter Sharon
Published: December 2007

The viscoelastic properties of the epoxy surface have been investigated by nanodynamic mechanical analysis (nano‐DMA). Both a Berkovich tip and a conospherical tip were used under the condition of different forces (i.e., different penetration depths) in the frequency range of 10–200 Hz. Loss tangent and storage modulus are characteristics that describe the viscoelastic properties. The effect of force frequency, penetration depth, and tip shape on the viscoelastic properties is studied and discussed according to the features of microstructures and mobility of molecular chains. The experimental results show important variations when the penetration depth is shallow (<30 nm). As the depth becomes deeper, the results tend to be stable and become almost constant over 120 nm. The two kinds of indenter tip can cause a slight difference of the storage modulus. A “master curve” of the storage modulus as a function of force frequency is established. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 281–288, 2008