bluuebunny/crossref_metadata_2025 huggingface dataset:
Neil MacCormick's Second Thoughts on Legal Reasoning and Legal Theory. A Defence of the Original View
Authors: SCHIAVELLO ALDO
Published: May 2011

This paper offers a diachronic reconstruction of MacCormick's theory of law and legal argumentation: In particular, two related points will be highlighted in which the difference between the perspective upheld in Legal Reasoning and Legal Theory and the later writings is particularly marked. The first point concerns MacCormick's gradual break with legal positivism, and more specifically the thesis that the implicit pretension to justice of law proves legal positivism false in all its different versions. The second point concerns MacCormick's acceptance of the one‐right‐answer thesis and the consequent thinning of the differences between MacCormick's theory of legal reasoning and that of Ronald Dworkin and of Robert Alexy. The intent, however, is not only to describe this change in MacCormick's thought, but also to attempt a defence of the original view that we find in Legal Reasoning and Legal Theory.
Women and Budget Deficits*
Authors: Krogstrup Signe , Wälti Sébastien
Published: May 2011

If women have different economic preferences than men, then female economic and political empowerment is likely to change economic policy, and in turn perhaps macroeconomic outcomes. In this paper, we narrow the focus to fiscal policy, and we investigate whether female enfranchisement affects government budget deficits. In a difference‐in‐differences regression for Swiss cantonal panel data, we find that the inclusion of women in the electorate has reduced deficits by a statistically significant amount.
Estimation for High‐Dimensional Linear Mixed‐Effects Models Using ℓ1‐Penalization
Authors: SCHELLDORFER JÜRG , BÜHLMANN PETER , DE GEER SARA VAN
Published: May 2011

Abstract.  We propose an ℓ1‐penalized estimation procedure for high‐dimensional linear mixed‐effects models. The models are useful whenever there is a grouping structure among high‐dimensional observations, that is, for clustered data. We prove a consistency and an oracle optimality result and we develop an algorithm with provable numerical convergence. Furthermore, we demonstrate the performance of the method on simulated and a real high‐dimensional data set.
The Double Gaussian Approximation for High Frequency Data
Authors: MYKLAND PER A. , ZHANG LAN
Published: May 2011

Abstract  High frequency data have become an important feature of many areas of research. They permit the creation of estimators in highly non‐parametric classes of continuous‐time models. In the context of continuous semi‐martingale models, we here provide a locally parametric ‘double Gaussian’ approximation, to facilitate the analysis of estimators. As in Mykland and Zhang (Econometrica, 77, 2009, p. 1403), the error in the approximation can be offset with a postasymptotic likelihood correction. The current approximation is valid in large neighbourhoods, permitting a sharp analysis of estimators that use local behaviour over asymptotically increasing numbers of observations.
The association between chronic psychosocial stress, allostatic load, and vascular health in asymptomatic young men: A pilot study using a novel finger arterial stiffness index1
Authors: TANAKA GOHICHI , KATO YUICHI , MATSUMURA KENTA , HORIGUCHI MASAMI , OGASAWARA HARUKO , SAWADA YUKIHIRO
Published: May 2011

A novel index of finger arterial stiffness (FSI) was tested in terms of the relationship with risk markers for preclinical cardiovascular disease. In addition, we examined if the association between psychosocial factors and FSI was explained by allostatic load markers in 37 healthy young men aged 24.8 ± 4.0 years. The FSI was devised based on an exponential model of the finger arterial pressure‐volume relationship. The allostatic load index (ALI) as a cumulative risk marker was defined by the mean of standard scores for nine variables: resting systolic and diastolic blood pressure, waist/hip ratio, high‐density lipoprotein cholesterol (HDL‐C), total cholesterol/HDL‐C ratio, triglycerides, hemoglobin A1c, insulin resistance, and high sensitivity C‐reactive protein (CRP). Partial correlations controlling for age were significant for FSI with HDL‐C (r = −.36), CRP (r = .39), ALI (r = .40), unhealthy overall eating habits (r = .34), hostility using the Buss‐Perry Aggression Questionnaire (r = .38), and manageability in Sense of Coherence (r = −.38). In conclusion, FSI seems to be associated with vascular proinflammation as well as with overall physiological dysregulation and allostatic load. These associations were moderated by eating lifestyle and psychosocial stress.
Blunted as well as exaggerated cardiovascular reactivity to stress is associated with negative health outcomes1
Authors: PHILLIPS ANNA C.
Published: May 2011

The reactivity hypothesis implicates exaggerated cardiovascular reactions to acute psychological stress in the development of hypertension and other cardiovascular disease outcomes. However, exaggerated cardiovascular reactivity has also been suggested as a mediator between a variety of psychosocial and behavioral risk factors and cardiovascular disease. Recent data analyses from the West of Scotland Twenty‐07 study and our own group are discussed together, to show that blunted as well as exaggerated cardiovascular reactivity to stress may be associated with negative health outcomes. Blood pressure and heart rate were assessed at rest and during an acute mental arithmetic stress task. We show that depression and obesity are associated with blunted rather than exaggerated reactivity. These seemingly paradoxical results are discussed in terms of implications for the reactivity hypothesis.
Modulation of stress reactivity in brain and body by serotonin transporter promoter polymorphism1
Authors: OHIRA HIDEKI
Published: May 2011

The polymorphism of the serotonin transporter gene in the promoter region (5HTTLPR) has been considered to link with vulnerability to depression and anxiety. This paper introduces a series of our studies showing that this genetic polymorphism can explain portions of individual differences in stress reactivity at multiple levels: brain functions, peripheral physiological responses, and behaviors. Specifically: (a) carriers of double short (S) alleles, compared with carriers of at least one long (L) allele, show greater activation in the hypothalamus and larger reactivity in blood catecholamine, cortisol, and an inflammatory cytokine to acute stress; (b) carriers of double S alleles are more sensitive to punishment, and thus show poorer performance in a decision‐making situation where they have to stick to a long‐term correct option regardless of short‐term punishment; and (c) carriers of double S alleles show greater activation of the amygdala and a correlation between amygdalar activity and an increase of natural killer cell proportion in blood when positive emotions are elicited. A possible model to explain the biological mechanisms underlying those phenomena is proposed and the ecological adaptive values of the 5HTTLPR genotypes are discussed.
VC Board Representation and Performance of US IPOs
Authors: Chahine Salim , Goergen Marc
Published: May 2011

Abstract: This paper studies the impact of five dimensions of venture capitalist (VC) power on the likelihood of the board representation of VCs in their portfolio firms at the initial public offering (IPO) as well as the effect of the latter on IPO performance. The dimensions of VC power are based onFinkelstein's (1992)four dimensions of power which are ownership power, structural power (i.e., the VC's rank within the firm's financial hierarchy), expert power (i.e., VC industry specialization), and prestige power (i.e., the number of IPOs the VC has been involved with so far). We add controlling power (i.e., how pivotal the VC is to the voted decision) to these four dimensions. We find that all five dimensions of power have a significantly positive impact on the likelihood of VC board membership. While controlling for the possible endogeneity of the latter, underpricing and the IPO premium are higher if there is VC board membership, which is consistent with both the grandstanding and management support hypotheses. Our results suggest that VCs improve IPO performance and that they do not just maintain a strong presence in better performing companies after the IPO.
Neuroprotective effects of granulocyte‐colony stimulating factor in a novel transgenic mouse model of SCA17
Authors: Chang Ya‐Chin , Lin Cheng‐Yueh , Hsu Chen‐Ming , Lin Hsin‐Chieh , Chen Yu‐Hsiang , Lee‐Chen Guey‐Jen , Su Ming‐Tsan , Ro Long‐Sun , Chen Chiung‐Mei , Hsieh‐Li Hsiu Mei
Published: May 2011

J. Neurochem. (2011) 118, 288–303.

Spinocerebellar ataxia type 17 (SCA17) is an autosomal dominant inherited disorder characterized by degeneration of spinocerebellar tracts and selected brainstem neurons owing to the expansion of a CAG repeat of the human TATA‐binding protein (hTBP) gene. To gain insight into the pathogenesis of this hTBP mutation, we generated transgenic mice with the mutant hTBP gene driven by the Purkinje specific protein (Pcp2/L7) gene promoter. Mice with the expanded hTBP allele developed ataxia within 2–5 months. Behavioral analysis of L7‐hTBP transgenic mice showed reduced fall latency in a rotarod assay. Purkinje cell degeneration was identified by immunostaining of calbindin and IP3R1. Reactive gliosis and neuroinflammation occurred in the transgenic cerebellum, accompanied by up‐regulation of GFAP and Iba1. The L7‐hTBP transgenic mice were thus confirmed to recapitulate the SCA17 phenotype and were used as a disease model to explore the potential of granulocyte‐colony stimulating factor in SCA17 treatment. Our results suggest that granulocyte‐colony stimulating factor has a neuroprotective effect in these transgenic mice, ameliorating their neurological and behavioral deficits. These data indicate that the expression of the mutant hTBP in Purkinje cells is sufficient to produce cell degeneration and an ataxia phenotype, and constitutes a good model for better analysis of the neurodegeneration in SCA17.
Cranial and appendicular ontogeny ofBactrosaurus johnsoni, a hadrosauroid dinosaur from the Late Cretaceous of northern China
Authors: PRIETO‐MÁRQUEZ ALBERT
Published: May 2011

Abstract: The juvenile anatomy of various cranial and appendicular elements of the hadrosauroid dinosaurBactrosaurus johnsoniis described in detail. Growth changes are documented from juvenile to adult stages for each skeletal element available. In the studied skull, ontogenetic trends consist of: development of features on the ventral surface of the frontal; reduction in the slope of the posteromedial process of the premaxilla; a posterior shift of the dorsal process of the maxilla; development of concavities on the medial surface of the prefrontal; increased robustness and development of the ventral flange of the jugal; decreased curvature of the long axis of the quadrate; increased ventral deflection of the dentary; and changes in the length/width proportions and depth of the anterior surface of the predentary. In the appendicular skeleton, the majority of ontogenetic variation from juvenile to adult occurs in the limb bones, including increased robustness of the deltopectoral crest of the humerus; relative shortening of the ulna; increased development of the fourth trochanter and mediolateral widening of the distal end of the femur; increased expansion of the cnemial crest of the tibia; and the increased prominence of articular protuberances and flanges of the metatarsals. A survey of the phylogenetically informative characters present inB. johnsoniindicates that several characters concerning the frontal, maxilla, jugal, quadrate, predentary, dentary, scapula, humerus and ilium are affected by ontogeny. Nevertheless, the majority of phylogenetic characters are not ontogenetically variable, suggesting that a substantial amount of the information provided by juvenile and subadult specimens for phylogenetic inference is reliable in basal hadrosauroids.
Adrenoceptor activity of muscarinic toxins identified from mamba venoms
Authors: Näreoja K , Kukkonen JP , Rondinelli S , Toivola DM , Meriluoto J , Näsman J
Published: May 2011

BACKGROUND AND PURPOSE Muscarinic toxins (MTs) are snake venom peptides named for their ability to interfere with ligand binding to muscarinic acetylcholine receptors (mAChRs). Recent data infer that these toxins may have other G‐protein‐coupled receptor targets than the mAChRs. The purpose of this study was to systematically investigate the interactions of MTs with the adrenoceptor family members.

EXPERIMENTAL APPROACH We studied the interaction of four common MTs, MT1, MT3, MT7 and MTα, with cloned receptors expressed in insect cells by radioligand binding. Toxins showing modest to high‐affinity interactions with adrenoceptors were additionally tested for effects on functional receptor responses by way of inhibition of agonist‐induced Ca2+ increases.

KEY RESULTS All MTs behaved non‐competitively in radioligand displacement binding. MT1 displayed higher binding affinity for the human α2B‐adrenoceptor (IC50= 2.3 nM) as compared with muscarinic receptors (IC50≥ 100 nM). MT3 appeared to have a broad spectrum of targets showing high‐affinity binding (IC50= 1–10 nM) to M4 mAChR, α1A‐, α1D‐ and α2A‐adrenoceptors and lower affinity binding (IC50≥ 25 nM) to α1B‐ and α2C‐adrenoceptors and M1 mAChR. MT7 did not detectably bind to other receptors than M1, and MTα was specific for the α2B‐adrenoceptor. None of the toxins showed effects on β1‐ or β2‐adrenoceptors.

CONCLUSIONS AND IMPLICATIONS Some of the MTs previously found to interact predominantly with mAChRs were shown to bind with high affinity to selected adrenoceptor subtypes. This renders these peptide toxins useful for engineering selective ligands to target various adrenoceptors.
VS‐105: a novel vitamin D receptor modulator with cardiovascular protective effects
Authors: Wu‐Wong J Ruth , Kawai Megumi , Chen Yung‐wu , Nakane Masaki
Published: May 2011

BACKGROUND AND PURPOSE Vitamin D receptor (VDR) modulators (VDRMs) such as calcitriol, paricalcitol and doxercalciferol are commonly used to manage hyperparathyroidism secondary to chronic kidney disease (CKD). CKD patients experience extremely high risks of cardiovascular morbidity and mortality. Clinical observations show that VDRM therapy may be associated with cardio‐renal protective and survival benefits for CKD patients. However, hypercalcaemia remains a serious side effect for current VDRMs, which leads to the need for frequent dose titration and serum Ca (calcium) monitoring. Significant clinical benefits can be derived from a VDRM with cardiovascular protective effects without the hypercalcaemic liability.

EXPERIMENTAL APPROACH Male Sprague–Dawley rats were 5/6 nephrectomized and 6 weeks later, after they had established uraemia, elevated parathyroid hormone levels, endothelial dysfunction and left ventricular hypertrophy, the rats were treated with VS‐105, a novel VDRM. The effects of VS‐105 were also tested in cultured HL‐60 cells.

KEY RESULTS VS‐105 induced HL‐60 cell differentiation with an EC50 value at 11.8 nM. Treatment (i.p., 3× a week over a period of 2 weeks) of the 5/6 nephrectomized rats by VS‐105 (0.004–0.64 µg·kg−1) effectively suppressed serum parathyroid hormone without raising serum Ca or phosphate levels. Furthermore, 2 weeks of treatment with VS‐105 improved endothelium‐dependent aortic relaxation and attenuated left ventricular abnormalities in a dose range that did not affect serum Ca levels. Similar results were obtained when VS‐105 was administered i.p. or by oral gavage.

CONCLUSIONS AND IMPLICATIONS VS‐105 exhibits an overall therapeutic product profile that supports expanded use in CKD to realize the cardiovascular protective effects of VDR activation.
Skeletal lipidomics: regulation of bone metabolism by fatty acid amide family
Authors: Bab Itai , Smoum Reem , Bradshaw Heather , Mechoulam Raphael
Published: May 2011

There is increasing evidence demonstrating that fatty acid derivatives play a key regulatory role in a variety of tissues. However, the study of skeletal lipidomics is just emerging and global strategies, such as targeted lipidomics, have not been applied to bone tissue. Such strategies hold great promises as in the case of genomics and proteomics. A partial profile of endocannabinoids and endocannabinoid‐like compounds has demonstrated the presence of several long‐chain fatty acid amides (FAAs), some of which displaying potent effects on osteoblasts, the bone forming cells and osteoclasts, the bone resorbing cells. In the skeleton, the FAAs activate the CB1 cannabinoid receptor present in sympathetic nerve terminals as well as CB2 cannabinoid receptor, the Gi‐protein coupled receptor GPR55, and the transient receptor potential vanilloid type ion channel expressed by osteoblasts and/or osteoclasts. This review on the skeletal FAA system focuses on the production of FAAs in the skeleton and their net bone anabolic and anti‐catabolic activity resulting from the stimulation of bone formation and inhibition of bone resorption. As the FAA family holds great promise as a basis for the treatment of osteoporosis and other diseases involving bone, further studies should aim towards the complete profiling of these lipids and their receptors in bone tissue, followed by elucidation of their function and mechanism of action.

LINKED ARTICLES This article is part of a themed issue on Cannabinoids in Biology and Medicine. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.163.issue‐7
Depletion and recovery of lymphoid subsets following morphine administration
Authors: Zhang EY , Xiong J , Parker BL , Chen AY , Fields PE , Ma X , Qiu J , Yankee TM
Published: May 2011

BACKGROUND AND PURPOSE Opioid use and abuse has been linked to significant immunosuppression, which has been attributed, in part, to drug‐induced depletion of lymphocytes. We sought to define the mechanisms by which lymphocyte populations are depleted and recover following morphine treatment in mice.

EXPERIMENTAL APPROACH Mice were implanted with morphine pellets and B‐ and T‐cell subsets in the bone marrow, thymus, spleen and lymph nodes were analysed at various time points. We also examined the effects of morphine on T‐cell development using an ex vivo assay.

KEY RESULTS The lymphocyte populations most susceptible to morphine‐induced depletion were the precursor cells undergoing selection. As the lymphocytes recovered, more lymphocyte precursors proliferated than in control mice. In addition, peripheral T‐cells displayed evidence that they had undergone homeostatic proliferation during the recovery phase of the experiments.

CONCLUSIONS AND IMPLICATIONS The recovery of lymphocytes following morphine‐induced depletion occurred in the presence of morphine and via increased proliferation of lymphoid precursors and homeostatic proliferation of T‐cells.

LINKED ARTICLE This article is commented on by Eisenstein, pp. 1826–1828 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476‐5381.2011.01513.x
Physical Activity Among South Asian Indian Immigrants: An Integrative Review
Authors: Daniel Manju , Wilbur JoEllen
Published: May 2011

ABSTRACT Objective(s):The aim of this research review was to portray the correlates of lifestyle physical activity (PA) behavior of healthy South Asian Indian (SAI) immigrants comprehensively by identifying, synthesizing, and critically analyzing the existing research literature.

Design and Sample:An integrative review methodology was used. The sample included 11 cross‐sectional and 4 qualitative studies.

Measures:The physical activity framework for SAI immigrants guided the development of data collection tools that included study measures of PA and background (current health, acculturation, discrimination, social support, environmental) and intrapersonal (motivation) correlates of PA.

Results:Regardless of the PA measure used, all studies reported low PA levels in at least 40% of the participants. The correlates of PA most often studied were sociodemographic variables, current health, and acculturation; female sex; poorer health; and less time since immigration. Few studies focused on social support, environmental factors, or included dynamic motivational factors.

Conclusions:Increased knowledge of the factors that impact lifestyle PA is needed so that public health nurses can develop targeted interventions to increase the lifestyle PA of SAI immigrants at risk for cardiovascular disease, diabetes, and central obesity.
Undermining of Nutrition and Exercise Decisions: Experiencing Negative Social Influence
Authors: Mackert Michael , Stanforth Dixie , Garcia Alexandra A.
Published: May 2011

ABSTRACT Objective:

The objective of this research was to assess social undermining (negative interpersonal influence) on health behaviors in a large sample of Internet users.

Design and Sample: This study used a cross‐sectional descriptive design with an online survey that yielded quantitative and qualitative data. A total of 6,923 individuals received invitations and 1,270 participants completed the survey (18.3% response rate). Respondents completing at least 1 qualitative question were retained for analysis (n=1,158). The sample had more females (75.9%) than males (24.1%) and an average age of 42.9 years (SD±12.4).

Measures: Participants described experiences and perceptions of undermining. Content analysis was used to identify themes, and responses were coded after establishing intercoder reliability (κ=.92). Coded responses were correlated with gender, body mass index, and satisfaction with weight.

Results: Many respondents reported that they were affected by undermining. The most common sources of undermining were family and significant others. Individuals satisfied with their current weight were more likely to resist undermining. Many suggested undermining might result from jealousy or others' guilt over their own decisions.

Conclusions: Undermining of healthy behaviors is an important issue for public health researchers and practitioners as it pertains to patient counseling and the development of strategies for resisting undermining.
Pachyonychia Congenita with Laryngeal Obstruction
Authors: Haber Richard M. , Drummond Derek
Published: May 2011

Abstract:  Pachyonychia congenita is a rare genodermatosis that can affect the larynx. Laryngeal obstruction is very unusual with only a few cases reported. A 2‐year‐old girl presented with typical clinical features of pachyonychia congenita shortly after birth. At age 9 months, following an upper respiratory infection, she developed stridor and hoarseness and was found to have severe laryngeal obstruction, which was felt to be secondary to pachyonychia congenita based on direct laryngoscopy and laryngeal biopsy. Leukokeratosis of her larynx was treated with CO2 laser on three occasions, with improvement in her respiratory distress after each treatment. This report is the first case of pachyonychia congenita with laryngeal obstruction in which the gene mutation has been established (a deletional mutation in K6a), confirming that laryngeal obstruction can occur in PC‐1.
Gianotti‐Crosti Syndrome After H1N1‐INFLUENZA Vaccine
Authors: KROESKOP ANNEBETH , LEWIS AMY B. , BARRIL FE A. F. , BARIBAULT KEITH E.
Published: May 2011

Abstract:  Papular acrodermatitis of childhood, or Gianotti‐Crosti syndrome, is a symmetric papular or papulovesicular acral exanthem associated with several infectious agents and immunizations. We present a case of Gianotti‐Crosti syndrome appearing shortly after H1N1‐influenza vaccination. This has not been previously reported to our knowledge.
Relations of Early Goal‐Blockage Response and Gender to Subsequent Tantrum Behavior
Authors: Sullivan Margaret W. , Lewis Michael
Published: May 2011

Infants and their mothers participated in a longitudinal study of the sequelae of infant goal‐blockage responses. Four‐month‐old infants participated in a standard contingency learning and goal‐blockage procedure during which anger and sad facial expressions to the blockage were coded. When infants were 12 and 20 months old, mothers completed a questionnaire about their children’s tantrums. Tantrum scores increased with age and boys tended to show more tantrum behavior than girls. Anger expressed to goal blockage at 4 months was unrelated to tantrum behavior. There was a gender by sad expression interaction. Girls who expressed sadness in response to the goal blockage had lower total tantrum scores than boys; otherwise there was no difference. These results suggest that tantrums of infants who display sad, not anger expression, in response to goal blockage, are differentially influenced by children’s gender.
Red blood cell storage is associated with length of stay and renal complications after cardiac surgery
Authors: Sanders Julie , Patel Sanjiv , Cooper Jackie , Berryman Jennifer , Farrar Daniel , Mythen Michael , Montgomery Hugh E.
Published: May 2011

BACKGROUND: The association of red blood cell (RBC) storage on morbidity outcome after cardiac surgery is debated. We sought to clarify the association of the age of transfused blood on outcome in patients undergoing cardiac surgery.

STUDY DESIGN AND METHODS: Data were drawn from a prospective, observational cohort study of morbidity outcome in patients undergoing cardiac surgery. Blood transfusion data were obtained retrospectively via the Trust blood bank electronic records. Old blood was defined as more than 14 days old. The primary outcome measure was postoperative length of stay (PLOS). Secondary outcome measures included renal failure and morbidity as defined within the postoperative morbidity survey.

RESULTS: A total of 176 (39.6%) of 444 participants received a blood transfusion. Patients transfused with new blood had a reduced PLOS compared with patients receiving exclusively old or any old blood (old blood ± new blood; 7 days vs. 8 days, p = 0.04 and vs. 10 days, p = 0.002, respectively). In patients who only had 1 unit transfused, PLOS was longer in those receiving only old blood compared with those receiving only new blood (8 days vs. 6 days, p = 0.02) with a 3.8‐fold risk of longer stay. Compared with patients receiving exclusively new blood, patients receiving any old blood had a higher incidence of new renal complications (65.7% vs. 43.9%, p = 0.008). Each 1‐day increase in storage was associated with a 7% increase in risk of new renal complications.

CONCLUSION: Our data support previous suggestions of an association between transfusion of older RBCs and poorer outcome in cardiac surgery patients. Randomized controlled trials are required to determine the true causal nature of any such association.
Reexamination of the Role of SrMoO4 in the Enhancement of the Low‐Field Magnetoresistance of Sr2FeMoO6
Authors: Fang Tsang‐Tse , Lin Jung‐Cheng
Published: May 2011

Different ratios of the precursor phases of SrFeO3–x (SFO) and SrMoO4 (SMO) were used to prepare Sr2FeMoO6 (SFMO) by a solid‐state reaction. X‐ray diffraction was used to identify the phases. A residual SMO was observed to exist in the sample with an SFO/SMO ratio of 0.9:1. The sample with a residual SMO phase had higher resistivity, lower magnetization, but higher low‐field magnetoresistance (LFMR). High‐resolution transmission electron microscopy was used to identify the compositions and phases. Nanometer‐sized amorphous‐like clusters of SMO phase were located inside the grains rather than at grain boundaries; however, some boundaries were rich in the strontium ion. The possible mechanisms for the conduction and the increase of LFMR of SFMO are discussed.
Effect of Preforming Process and Starting Fused SiO2 Particle Size on Microstructure and Mechanical Properties of Pressurelessly Sintered BNp/SiO2 Ceramic Composites
Authors: Jia Dechang , Zhou Lizhong , Yang Zhihua , Duan Xiaoming , Zhou Yu
Published: May 2011

Hexagonal BN particles (BNp) reinforced fused SiO2 matrix composite (BNp/SiO2) was regarded as a very important candidate material for potential applications on wave transparent thermal protection parts. In this study, pressurelessly sintered 15 vol% BNp/SiO2 composites were prepared by cold isostatic pressing (CIP) and gel‐casting routes, respectively, using two kinds of fused silica powders with different particle sizes (5.82 and 3.24 μm in d50, respectively) as starting SiO2. It was demonstrated that the microstructure and mechanical properties of the composites were well dependent on the preforming techniques of green compacts. Gel‐casting preforming route has an overwhelming superiority over CIP route on the thermal stability of fused SiO2 matrix against α‐cristobalite crystallization, sinterability, and thus the mechanical properties. Using the finer fused silica (3.24 μm in d50) as the starting SiO2, the 15 vol% BNp/SiO2 composite sintered at 1375°C get a density of 2.05 g/cm3, the silica matrix primarily keep amorphous phase with uniformly dispersed nanosized α‐cristobalite crystallites (<5 nm in diameter). The bending strength, fracture toughness and Young's modulus all reach the highest values, 101.5 ± 4.3 MPa, 1.57 ± 0.04 MPa·m1/2 and 61.3 ± 2.4 GPa, respectively. Microstructure characteristics, chemical bond information and mechanical properties of the as‐prepared composites are correlated with their preforming routes, starting fused SiO2 particle size, sintering temperature, etc. based on X‐ray diffractometry, scanning electron microscope, transmission electron microscope, high resolution transmission electron microscope, and FT‐IR analysis.
Improving the High‐Temperature Oxidation Resistance of Ti3(SiAl)C2by Nb‐Doping
Authors: Zheng Li‐Li , Sun Lu‐Chao , Li Mei‐Shuan , Zhou Yan‐Chun
Published: May 2011

A (TiNb)3(SiAl)C2solid solution was designed and synthesized to improve the high‐temperature oxidation resistance of Ti3(SiAl)C2. After doping with Nb, the oxidation resistance of Ti3(SiAl)C2is improved. Its oxidation kinetics follows parabolic behavior up to 1300°C. The oxide scale formed on (TiNb)3(SiAl)C2is thinner and smaller in grain size than that on Ti3(SiAl)C2under the same oxidation condition. The beneficial effect of Nb doping on the oxidation resistance of Ti3(SiAl)C2mainly results from the decreased concentration of oxygen vacancies and titanium interstitials in the rutile form of TiO2, and the inhibited generation of excessive voids in the oxide scale.
X‐Ray Photoelectron Spectroscopy Study on the Interaction of Yttrium–Aluminum Oxide with Fluorine‐Based Plasma
Authors: Kim Dae‐Min , Lee Sang‐Ho , Alexander William B. , Kim Kyeong‐Beom , Oh Yoon‐Suk , Lee Sung‐Min
Published: May 2011

We have prepared oxides having various yttrium to aluminum ratios and exposed them to fluorine‐based plasma. The etch rate of the aluminum oxide decreased abruptly with the addition of yttrium oxide and then slowly with further addition. The yttrium oxide had a more fluorinated surface than the aluminum oxide, indicating that the etch rate was not determined by the surface fluorination, contrary to the etching of Si‐based materials. From the X‐ray photoelectron spectroscopy (XPS) analysis of a multication YAlO3 single crystal, a similar tendency was observed, showing a higher ratio of Y–F to Y–O bonding than the ratio of Al–F to Al–O. Angle resolved XPS and depth profiling analysis revealed the presence of a fluorinated layer of a few nanometer thick under a roughly 1 nm carboneous top layer. The etching behavior and surface chemical status of these oxides were discussed in terms of thermodynamic aspects of aluminum and yttrium fluoride.
Self‐administered symphysis–fundus measurements analyzed with a novel statistical method for detection of intrauterine growth restriction: a clinical evaluation
Authors: BERGMAN EVA , AXELSSON OVE , PETZOLD MAX , SONESSON CHRISTIAN , KIELER HELLE
Published: May 2011

Objective. To assess the ability of self‐administered symphysis–fundus measurements used with the Shiryaev–Roberts statistical method (SR method) to identify growth‐restricted (IUGR) fetuses and compare it with the traditional SF method (symphysis–fundus measurements used with a population‐based reference curve). Design. Longitudinal study. Setting. Pregnant women attending primary antenatal care centres. Population. From a population of 1 888 women with singleton ultrasound‐dated pregnancies, we analyzed data from 1 122 women. Methods. Weekly self‐administered SF measurements from gestational week 25 until delivery were analyzed according to the SR method. Neonatal morbidity and small for gestational age (SGA) were used as proxies for IUGR. Small for gestational age was defined as a birthweight less than two standard deviations (SD) and <10th percentile. We assessed the sensitivity of the SR and the SF methods to detect neonatal morbidity and SGA. Main Outcome Measures. Birth‐related mortality, respiratory distress, hypoglycemia, Apgar score ≤6 at five minutes, pH ≤7.00 in the umbilical artery, neonatal care, preterm delivery, operative delivery for fetal distress and SGA. Results. For the SR method, the sensitivity for neonatal morbidity was between 6.0 and 36.4%, for SGA <2SD 36.8%, and for SGA <10th percentile 20.9%. The SF method had a sensitivity between 6.0 and 13.8% for neonatal morbidity, 52.3% for SGA <2SD and 28.6% for SGA <10th percentile. Conclusions. The SR and the SF methods had low sensitivities for neonatal morbidity.
Resorption of deproteinized bovine bone mineral in a porcine calvaria augmentation model
Authors: Busenlechner Dieter , Tangl Stefan , Arnhart Christoph , Redl Heinz , Schuh Christian , Watzek Georg , Gruber Reinhard
Published: May 2011

Objectives: The original aim of the study was to determine the osteoconductive capacity of deproteinized bovine bone mineral (DBBM) of different particle sizes underneath acrylic hemispheres in vivo. However, the model failed and allowed us to report on the resorption of DBBM.

Material and methods: Acrylic hemispheres were filled with and without a DBBM at a small particle size of 125–250 μm and at the regular particle size of 250–1000 μm. The hemispheres were positioned on the calvaria of eight minipigs. Histological and histomorphometric analysis was performed after 12 weeks.

Results: We found that the acrylic hemispheres were displaced and a dense fibrous capsule sequestered the augmented area. Histology showed severe resorption activity and the presence of multinucleated cells on the surface of DBBM particles in areas adjacent to the fibrous capsule. Histomorphometric analysis revealed that only less than half of the originally augmented area, which was approximately 30 mm2, remained after 12 weeks. The amount of residual DBBM (median 0.9 and 3.49 mm2) and bone (median 7.22 and 7.51 mm2) in the augmented area was similar in the small and the regular particle size group.

Conclusion: The model represents a pathologic situation of excess resorption of DBBM and bone in an augmented area. The underlying cellular mechanisms remain to be uncovered.

To cite this article: Busenlechner D, Tangl S, Arnhart C, Redl H, Schuh C, Watzek G, Gruber R. Resorption of deproteinized bovine bone mineral in a porcine calvaria augmentation model. Clin. Oral Impl. Res. 23, 2012; 95–99. doi: 10.1111/j.1600‐0501.2011.02198.x
Three ways of understanding development as a teacher
Authors: Stenfors‐Hayes T. , Hult H. , Dahlgren L. O.
Published: May 2011

The demands on faculty in terms of teaching are increasing, but until recently there has been little discussion of how faculty perceive that development as a teacher can be achieved or what approaches they use or suggest themselves. The aim of this study is to explore how teachers in dentistry and medicine understand development as teachers. For this study, 20 teachers were interviewed. The interviews were analysed using a phenomenographic approach. Three different ways of understanding development were identified: 1) Development as a dental or medical clinician/expert as the teacher role is seen as a tacit part of the role of the clinician. 2) Experience and professional and personal maturation, related to personal and professional development and confidence in ones clinical role. 3) Knowledge in education and systematic teacher training as in this category, being a teacher is seen as a separate role from that of being a clinician. The differences in these three ways of understanding development as a teacher are shown in their different aims of development, what kind of knowledge that may be used and what methods they suggested. The way teachers understand what it means to develop as a teacher will affect their motivation for engaging in development activities, which activities they choose and their own aims of development. This means that awareness of teachers’ understanding of development is central when developing support or faculty development activities for teachers.
Predator diversity effects cascade across an ecosystem boundary
Authors: Wesner Jeff Scott
Published: May 2011

Food webs in different ecosystems are often connected through spatial resource subsidies. As a result, biodiversity effects in one ecosystem may cascade to adjacent ecosystems. I tested the hypothesis that aquatic predator diversity effects cascade to terrestrial food webs by altering a prey subsidy (biomass and trophic structure of emerging aquatic insects) entering terrestrial food webs, in turn altering the distribution of a terrestrial consumer (spider) that feeds on emerging aquatic insects. Fish presence, but not diversity, altered the trophic structure of emerging aquatic insects by strongly reducing the biomass of emerging predators (dragonflies) relative to non‐feeding taxa (chironomid midges). Fish diversity reduced emerging insect biomass through enhanced effects on the most common prey taxa: predatory dragonflies Pantala flavescens and non‐feeding chironomids. Terrestrial spiders (Tetragnathidae) primarily captured emerging chironomids, which were reduced in the high richness (3 spp.) treatment relative to the 1 and 2 species treatments. As a result, terrestrial spider abundance was lower above pools with high fish richness (3 species) than pools with 1 and 2 species. Synergistic predation effects were mostly limited to the high richness treatment, in which fish occupied each level of vertical microhabitat in the water‐column (benthic, middle, surface). This study demonstrates that predator diversity effects are not limited to the habitat of the predator, but can propagate to adjacent ecosystems, and demonstrates the utility of using simple predator functional traits (foraging domain) to more accurately predict the direction of predator diversity effects.
Hierarchical spatial structure of stream fish colonization and extinction
Authors: Hitt Nathaniel P. , Roberts James H.
Published: May 2011

Spatial variation in extinction and colonization is expected to influence community composition over time. In stream fish communities, local species richness (alpha diversity) and species turnover (beta diversity) are thought to be regulated by high extinction rates in headwater streams and high colonization rates in downstream areas. We evaluated the spatiotemporal structure of fish communities in streams originally surveyed by Burton and Odum 1945 (Ecology 26: 182–194) in Virginia, USA and explored the effects of species traits on extinction and colonization dynamics. We documented dramatic changes in fish community structure at both the site and stream scales. Of the 34 fish species observed, 20 (59%) were present in both time periods, but 11 (32%) colonized the study area and three (9%) were extirpated over time. Within streams, alpha diversity increased in two of three streams but beta diversity decreased dramatically in all streams due to fish community homogenization caused by colonization of common species and extirpation of rare species. Among streams, however, fish communities differentiated over time. Regression trees indicated that reproductive life‐history traits such as spawning mound construction, associations with mound‐building species, and high fecundity were important predictors of species persistence or colonization. Conversely, native fishes not associated with mound‐building exhibited the highest rates of extirpation from streams. Our results demonstrate that stream fish colonization and extinction dynamics exhibit hierarchical spatial structure and suggest that mound‐building fishes serve as keystone species for colonization of headwater streams.
Drought changes plant chemistry and causes contrasting responses in lepidopteran herbivores
Authors: Gutbrodt Bettina , Mody Karsten , Dorn Silvia
Published: May 2011

Drought events are predicted to increase due to climate change, yet consequences for plant–insect interactions are only partially understood. Drought‐mediated interactions between herbivores and their host plants are affected by a combination of factors, including characteristics of the affected plant, its associated herbivore and of the prevailing drought. Studying the effect of these factors in combination may provide important insight into plant and herbivore responses to drought. We studied drought effects on plant resistance to two leaf‐chewing herbivores by considering differing growth conditions, plant chemistry and insect responses in concert. We exposed Alliaria petiolata plants from several wild populations to different intensities of intermittent drought stress and quantified drought‐mediated changes in plant chemistry. Simultaneously, we assessed behavior (feeding preference) and performance of two lepidopteran herbivores: Pieris brassicae, a specialist, and Spodoptera littoralis, a generalist. Drought led to lowest concentrations of secondary defense compounds in severely stressed plants, without affecting total nitrogen content. Additionally, drought evoked opposite patterns in feeding preferences (plant palatability) between the herbivore species. Pieris brassicae consumed most of well‐watered plants, while S. littoralis preferred severely drought‐stressed plants. Hence, feeding preferences of S. littoralis reflected changes in plant secondary chemistry. Contrary to their feeding preference, P. brassicae performed better on drought‐stressed than on well‐watered plants, with faster development and higher attained pupal mass (plant suitability). Spodoptera littoralis showed retarded development in all treatments. In conclusion, drought caused plant secondary defense compounds to decrease consistently across all studied plant populations, which evoked contrasting feeding preferences of two herbivore species of the same feeding guild. These results suggest herbivore specificity as a possible explanation for herbivore responses to drought and emphasize the importance of herbivore characteristics such as feeding specialization in understanding and predicting consequences of future drought events.
Central nervous system processing of emotions in children with faecal incontinence
Authors: Becker A , Rubly M , El Khatib D , Becker N , von Gontard A
Published: May 2011

Aim:  Faecal incontinence (FI) is a common disorder involving both the enteric (ENS) and central nervous systems (CNS). The aim of the study is to analyze neurophysiologically the central processing of emotions in children with FI, healthy controls and children with Attention‐deficit hyperactivity disorder (ADHD).

Methods:  Fourteen children with FI and constipation, nine with non‐retentive FI, 15 controls and 13 children with ADHD were examined. The methods included a physical exam, sonography, Child Behavior Checklist, a psychiatric interview and intelligence test. Acoustic evoked potentials were recorded according to standardized methodology. For the event‐related potentials, 80 neutral, 40 positive and 40 negative pictures from the International Affective Picture System (IAPS), and 40 pictures depicting faeces were presented.

Results:  Children with FI had significantly more intense responses for most stimuli over the frontal, central and parietal regions compared to controls. Stool pictures did not evoke stronger responses than other stimuli. Children with constipation elicited stronger responses. Children with ADHD did not differ from controls. Acoustic evoked potentials were comparable in all groups.

Conclusions:  Children with FI have increased responses in the processing of emotions. These can be interpreted as a neurobiological vulnerability, possibly due to the association of the ENS and CNS.
Analysis of New Bone Formation Induced by Periosteal Distraction in a Rat Calvarium Model
Authors: Saulacic Nikola , Schaller Benoit , Iizuka Tateyuki , Buser Daniel , Hug Cladius , Bosshardt Dieter D.
Published: May 2011

Background: A controlled, gradual distraction of the periosteum is expected to result in the formation of new bone.

Purpose: This study was designed to estimate the possibility of new bone formation by periosteal distraction in a rat calvarium model.

Material and Methods: Sixteen animals were subjected to a 7‐day latency period and distraction rate at 0.4 mm/24 hours for 10 days. Two experimental groups with seven rats each were killed at 10 and 20 days of consolidation period and analyzed by means of microcomputed tomography, histologically and histomorphometry.

Results: In the central regions underneath the disk device, signs of both bone apposition and bone resorption were observed. Peripheral to the disc, new bone was consistently observed. This new bone was up to two and three times thicker than the original bone after a 10‐ and 20‐day consolidation period, respectively. Signs of ongoing woven bone formation indicated that the stimulus for new bone formation was still present. There were no statistically significant differences regarding bone density, bone volume, and total bone height between the two groups.

Conclusion: The periosteal distraction model in the rat calvarium can stimulate the formation of considerable amounts of new bone.
One‐Year Results of a Clinical and Radiological Prospective Multicenter Study on NEOSS® Dental Implants
Authors: Dahlin Christer , Widmark Göran , Bergkvist Göran , Fürst Björn , Widbom Tor , Kashani Hossein
Published: May 2011

Background: NEOSS® (Neoss Ltd., Harrogate, UK) dental implant system was introduced on the clinical arena in 2003. It is important that novel implant systems are systematically evaluated in a multicenter setting.

Purpose: The aim of this study was to follow a large number of consecutively treated patients, with NEOSS dental implant system, both clinically and radiographically. The current report constitutes the 1‐year data of a planned 5‐year study.

Materials and Methods: The study included a total of 177 patients treated with 590 NEOSS implants at 13 clinics in Sweden. The material was composed of 72 males and 105 females treated for single, partial, and total edentulism. Clinical, radiographic, and subjective evaluations were performed.

Results: Out of 590 implants, 13 early failures have been reported, corresponding to a 1‐year cumulative survival rate (CSR) of 97.8%. Evaluation of function and esthetics at the 1‐year visit resulted in 100% success for function and 98% success for the esthetic outcome. The mean marginal bone loss was 0.6 mm (SD 1.1) after 1 year in clinical function. No adverse effects of the NEOSS dental implants were reported, and complications were few and similar to those reported for implant treatment in general.

Conclusion: The CSR in the present study was 97.8%. No adverse effects of the NEOSS implants were reported, and complications during the study period were few and similar to those reported to for other well‐documented implants system. Based on the present data, we conclude that NEOSS dental implant is a safe and predictable implant system. However, the high number of dropouts in the radiological evaluation must be considered when interpreting the data.