bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the theories of reasoned action and planned behaviour
Authors: Sideridis Georgios D. , Kaissidis Aggelos , Padeliadu Susana
Published: May 2011

Background. Ajzen & Fishbein's (1977) theory of reasoned action and, later Ajzen's planned behaviour theory (Ajzen, 1988; Ajzen & Madden, 1986) have received great attention in the literature (e.g., Giles & Cairns, 1995). A number of researchers have attempted to explain several aspects of human behaviour (e.g., Bandura, 1997). A review of literature between 1990 and 1997 using the Psychlit and ERIC databases which pertained to the application of the theories of reasoned action and/or planned behaviour for the explanation of student study behaviour for an upcoming examination revealed one study (Clarry & Burns, 1991) in which little support for the use of the theory of planned behaviour was provided.

Aims. The purpose of the present study was to examine the appropriateness of the theories of reasoned action (Ajzen & Fishbein, 1977) and planned behaviour (Ajzen & Madden, 1986) to explain student study behaviour during final examinations as pertaining to achieving a high Grade Point Average (GPA).

Sample. This comprised 136 freshmen Greek students from an American undergraduate institution located in Greece.

Method. A structural equation modelling analysis using EQS 4.02 (Bentler, 1992) was used to evaluate the construct validity of the theories of reasoned action and planned behaviour. In this modelling, latent variables were a function of measured variables and direct and indirect relationships were postulated in a path‐analysis framework in order to explain both theories. Since the theory of reasoned action was nested within the theory of planned behaviour, a direct comparison between them was feasible.

Results. Ajzen & Fishbein's (1977) theoretical framework (reasoned action) was well supported, providing a Comparative Fit Index (CFI) of .947. The only modification between the original (Ajzen & Fishbein, 1977) and the final structural model was a direct path between motivation to comply and study behaviour. This structural model provided significant improvement over the original model providing a CFI of .976 and a non‐significant value. Further, inclusion of the perceived control constructs produced a model with acceptable fit also (CFI = .934).

Conclusion. It is concluded that both theories describe well the study behaviour of students although inclusion of perceived behavioural control was not fully supported by the data.
Cognitive vulnerability to depression: An exploration of dysfunctional attitudes and ruminative response styles in the United Arab Emirates
Authors: Thomas Justin , Altareb Belkeis
Published: May 2011

Background. There has been little exploration of Beck's cognitive theory of depression and Nolen‐Hoeksem's response styles theory within Arab populations.

Objectives. The study investigates the generalizability of these clinically influential models to Emirati citizens residing within United Arab Emirates (UAE).

Method. An opportunity sample of 450 undergraduate participants was assessed for dysfunctional attitudes using an Arabic/English 40‐item version of Weissman and Beck's Dysfunctional Attitudes Scale (DAS). Participants also completed Arabic/English versions of Nolen‐Hoeksema's ruminative response styles (RRS) scale and the Beck Depression Inventory–II (BDI‐II).

Results. Correlation and regression analyses showed depression to be associated with both RRS and dysfunctional attitudes.

Conclusion. The study supports the generalization of these clinically influential theories of depression within a UAE context.
Living with parents with obsessive–compulsive disorder: Children's lives and experiences
Authors: Griffiths Jennifer , Norris Emma , Stallard Paul , Matthews Shane
Published: May 2011

Background. It has been well documented that parental mental health problems can lead to adverse consequences for their children. However, few studies have examined the subjective experiences of these children. Several parental mental health problems have been studied, but obsessive–compulsive disorder (OCD) has primarily been considered in relation to adult relatives of the sufferer only.

Aims. This study aimed to explore the experiences of young people with a parent with OCD, including the impact of parental OCD and their understanding of it.

Method. Semi‐structured interviews were conducted with ten 13‐ to 19‐year‐olds with a parent with OCD. The data were analysed using inductive thematic analysis.

Results. Five themes were identified: ‘Control and boundaries’; ‘Doing what I can to help’; ‘Telling: embarrassment and pride’; ‘Do I have OCD?’; and ‘Getting the right help for me’.

Conclusions. Parental OCD presented challenges to participants and placed burden upon them, for which they did not receive adequate support. The issues raised by parental OCD seemed similar to other parental mental health problems, but the results suggested that the child's developmental stage may be a significant influence.
The Effect of Iso-Octane Addition on Combustion and Emission Characteristics of a HCCI Engine Fueled With n-Heptane
Authors: Dumitrescu Cosmin E. , Guo Hongsheng , Hosseini Vahid , Neill W. Stuart , Chippior Wallace L. , Connolly Trevor , Graham Lisa , Li Hailin
Published: May 2011

This paper investigates the effects of iso-octane addition on the combustion and emission characteristics of a single-cylinder, variable compression ratio, homogeneous charge compression ignition (HCCI) engine fueled with n-heptane. The engine was operated with four fuel blends containing up to 50% iso-octane by liquid volume at 900 rpm, 50:1 air-to-fuel ratio, no exhaust gas recirculation, and an intake mixture temperature of 30°C. A detailed analysis of the regulated and unregulated emissions was performed including validation of the experimental results using a multizone model with detailed fuel chemistry. The results show that iso-octane addition reduced HCCI combustion efficiency and retarded the combustion phasing. The range of engine compression ratios where satisfactory HCCI combustion occurred was found to narrow with increasing iso-octane percentage in the fuel. NOx emissions increased with iso-octane addition at advanced combustion phasing, but the influence of iso-octane addition was negligible once CA50 (crank angle position at which 50% heat is released) was close to or after top dead center. The total unburned hydrocarbons (THC) in the exhaust consisted primarily of alkanes, alkenes, and oxygenated hydrocarbons. The percentage of alkanes, the dominant class of THC emissions, was found to be relatively constant. The alkanes were composed primarily of unburned fuel compounds, and iso-octane addition monotonically increased and decreased the iso-octane and n-heptane percentages in the THC emissions, respectively. The percentage of alkenes in the THC was not significantly affected by iso-octane addition. Iso-octane addition increased the percentage of oxygenated hydrocarbons. Small quantities of cycloalkanes and aromatics were detected when the iso-octane percentage was increased beyond 30%.
Exergoeconomic Analysis of an Advanced Zero Emission Plant
Authors: Petrakopoulou Fontina , Tsatsaronis George , Morosuk Tatiana
Published: May 2011

In this paper, an advanced zero emission plant using oxy-fuel combustion is presented and compared with a reference plant (a) without CO2 capture and (b) with CO2 capture via chemical absorption. A variation of the oxy-fuel plant with a lower CO2 capture percentage (85%) is also presented, in order to (1) evaluate the influence of CO2 capture on the overall performance and cost of the plant and (2) enable comparison at the plant-level with the conventional method for CO2 capture: chemical absorption with monoethanolamine. Selected results of an advanced exergetic analysis are also briefly presented to provide an overview of further development of evaluation methodologies, as well as deeper insight into power plant design. When compared with the reference case, the oxy-fuel plants with 100% and 85% CO2 captures suffer only a relatively small decrease in efficiency, essentially due to their more efficient combustion processes that make up for the additional thermodynamic inefficiencies and energy requirements. Investment cost estimates show that the membrane used for the oxygen production in the oxy-fuel plants is the most expensive component. If less expensive materials can be used for the mixed conducting membrane reactor used in the plants, the overall plant expenditures can be significantly reduced. Using the results of the exergoeconomic analysis, the components with the higher influence on the overall plant are revealed and possible changes to improve the plants are suggested. Design modifications that can lead to further decreases in the costs of electricity and CO2 capture, are discussed in detail. Overall, the calculated cost of electricity and the cost of avoided CO2 from the oxy-fuel plants are calculated to be competitive with those of chemical absorption.
Experimental results and numerical modeling of a high-performance large-scale cryopump. I. Test particle Monte Carlo simulation
Authors: Luo Xueli , Day Christian , Haas Horst , Varoutis Stylianos
Published: May 2011

For the torus of the nuclear fusion project ITER (originally the International Thermonuclear Experimental Reactor, but also Latin: the way), eight high-performance large-scale customized cryopumps must be designed and manufactured to accommodate the very high pumping speeds and throughputs of the fusion exhaust gas needed to maintain the plasma under stable vacuum conditions and comply with other criteria which cannot be met by standard commercial vacuum pumps. Under an earlier research and development program, a model pump of reduced scale based on active cryosorption on charcoal-coated panels at 4.5 K was manufactured and tested systematically. The present article focuses on the simulation of the true three-dimensional complex geometry of the model pump by the newly developed ProVac3D Monte Carlo code. It is shown for gas throughputs of up to 1000 sccm (∼1.69 Pa m3/s at T = 0° C) in the free molecular regime that the numerical simulation results are in good agreement with the pumping speeds measured. Meanwhile, the capture coefficient associated with the virtual region around the cryogenic panels and shields which holds for higher throughputs is calculated using this generic approach. This means that the test particle Monte Carlo simulations in free molecular flow can be used not only for the optimization of the pumping system but also for the supply of the input parameters necessary for the future direct simulation Monte Carlo in the full flow regime.
Model scandate cathodes investigated by thermionic-emission microscopy
Authors: Kordesch M. E. , Vaughn J. M. , Wan C. , Jamison K. D.
Published: May 2011

Model thermionic cathodes with different oxide coatings have been surveyed using a combination of photoelectron emission microscopy and thermionic electron emission microscopy. The model cathodes are imaged directly at operating temperatures and the electron yield is measured with a Faraday cup located in the image plane. Cathodes with combinations of Ba, Sc, BaO, Sc2O3, and pulsed-laser-deposited Sc2O3 on W substrates have been examined. BaO deposited on Sc2O3 is the most stable cathode combination. Measurement of the W–Sc2O3–BaO cathode shows that the electron yield enhancement produced by BaO and Sc2O3 is a two-step process which requires that the BaO be on top of the Sc2O3. BaO does not need to be in direct contact with the W substrate.
A survey of acute self-reported infections in pregnancy
Authors: Lain Samantha J , Roberts Christine L , Warning Julia , Vivian-Taylor Josephine , Ford Jane B
Published: May 2011

Objective

The objective of this study was to estimate the weekly prevalence of self-reported recently acquired infections in women at least 20 weeks pregnant.

Design

We conducted a cross-sectional survey of pregnant women in a hospital antenatal clinic in Sydney, Australia between August 2008 and April 2009. Women were asked to report whether they had onset of a new infection in the 7 days before completing the questionnaire, and were asked for details of symptoms and medication taken.

Results

737 women at least 20 weeks pregnant completed the survey (94% of women approached). Five per cent of the completed questionnaires reported the onset of an infection in the 7 days prior to survey completion. When symptoms were analysed, 3.5% of women were classified as having a moderate or severe infection in the past 7 days. The most common infection reported was a cold/upper respiratory tract infection followed by gastroenteritis. Women pregnant with their first child had a lower rate of self-reported infection than women who had other children (2.9% vs 7.2%).

Conclusions

These results can be used to inform future research examining acute infection as a trigger for pregnancy complications.
Whatever happened to medical politics?
Authors: Emmerich Nathan
Published: May 2011

This paper argues the case for coming to see ‘medical politics’ as a topic or subject within medical education. First, its absence is noted from the wide array of paramedical subjects (medical ethics, history of medicine, the medical humanities, etc) currently given attention in both the medical education literature and in specific curricula. Second the author suggests that ‘the political’ is implicitly recognisable in the historical roots of medical ethics education, specifically in certain of the London Medical Group's activities, and also that the medical profession, or indeed any profession, cannot be understood as an apolitical form of social organisation either in its institutional or scientific (epistemic) forms. Some brief suggestions for introductory and advanced topics in medical politics are discussed and the degree to which medical politics ought to be taken seriously and delivered as part of medical education is considered. Ultimately the author concludes that medical politics might be considered a useful subject within medical education, but it is perhaps best understood as a perspective or approach that can contribute to the development of a more expansive perspective within the extant paramedical subjects.
LOCAL DERIVATIONS ON ALGEBRAS OF MEASURABLE OPERATORS
Authors: ALBEVERIO S. , AYUPOV SH. A. , KUDAYBERGENOV K. K. , NURJANOV B. O.
Published: May 2011

The paper is devoted to local derivations on the algebra [Formula: see text] of τ-measurable operators affiliated with a von Neumann algebra [Formula: see text] and a faithful normal semi-finite trace τ. We prove that every local derivation on [Formula: see text] which is continuous in the measure topology, is in fact a derivation. In the particular case of type I von Neumann algebras, they all are inner derivations. It is proved that for type I finite von Neumann algebras without an abelian direct summand, and also for von Neumann algebras with the atomic lattice of projections, the continuity condition on local derivations in the above results is redundant. Finally we give necessary and sufficient conditions on a commutative von Neumann algebra [Formula: see text] for the algebra [Formula: see text] to admit local derivations which are not derivations.
EXISTENCE RESULT FOR MEAN FIELD EQUATION OF THE EQUILIBRIUM TURBULENCE IN THE SUPER CRITICAL CASE
Authors: ZHOU CHUNQIN
Published: May 2011

This paper is concerned with the mean field equation of the equilibrium turbulence on a compact Riemannian surface. The solution existence is shown in the super-critical case without any assumption on the topology and the geometry of the surface.
QUANTIZATION FOR THE PRESCRIBED Q-CURVATURE EQUATION ON OPEN DOMAINS
Authors: MARTINAZZI LUCA
Published: May 2011

We discuss compactness, blow-up and quantization phenomena for the prescribed Q-curvature equation (-Δ)m uk = Vke2muk on open domains of ℝ2m. Under natural integral assumptions we show that when blow-up occurs, up to a subsequence [Formula: see text] where Ω0 ⋐ Ω is open and contains the blow-up points, L ∈ ℕ and Λ1 ≔ (2m - 1)! vol (S2m) is the total Q-curvature of the round sphere S2m. Moreover, under suitable assumptions, the blow-up points are isolated. We do not assume that Vk is positive.
AN EFFECTIVE VERSION OF A THEOREM OF KAWAMATA ON THE ALBANESE MAP
Authors: JIANG ZHI
Published: May 2011

We study the Albanese map of smooth complex projective varieties with small plurigenera. We provide criteria for the Albanese map to be surjective and to be an algebraic fiber space. These criteria are optimal in some sense.
BALANCED MULTIPLE DESCRIPTION SUBBAND CODING
Authors: WANG NING , PENG LIZHONG
Published: May 2011

Multiple description coding is one of the source coding techniques used to alleviate the problems of packet loss in network. The objective is to encode a source into two (or more) bitstreams supporting two quality levels of decoding: A high-quality reconstruction decoded from the two bitstreams together, and two lower ones, but still acceptable, decoded from either of the two bitstreams individually. Most of the earlier works concentrated on the trade-off between redundancy and average side distortion, which is insufficient to evaluate the system performance. In this paper, we discuss the difference in quality between the two side reconstructions, which is defined as the balance eccentric modulus of the coding system. A scenario to design balanced multiple description coding system is presented. Application to the popular first-order autoregressive model yields encouraging results.
NONLINEAR WAVELET DENSITY ESTIMATION FOR TRUNCATED AND DEPENDENT OBSERVATIONS
Authors: CAI JUAN-JUAN , LIANG HAN-YING
Published: May 2011

In this paper, we provide an asymptotic expression for mean integrated squared error (MISE) of nonlinear wavelet density estimator for a truncation model. It is assumed that the lifetime observations form a stationary α-mixing sequence. Unlike for kernel estimator, the MISE expression of the nonlinear wavelet estimator is not affected by the presence of discontinuities in the curves. Also, we establish asymptotic normality of the nonlinear wavelet estimator.
APPLICATION OF THE DISCRETE WAVELET TRANSFORM FOR THE ROBUST DETECTION OF THE IMPULSIVE INCIDENCES: APPLICATION TO ARTERIAL BLOOD PRESSURE CHARACTERISTIC EVENTS DETECTION–DELINEATION
Authors: HOMAEINEZHAD MOHAMMAD R. , AGHAEE MOHAMMAD , TOOSI HAMID NAJJARAN , GHAFFARI ALI , RAHMANI REZA
Published: May 2011

The major focus of this study is to describe the structure of a solution designed for robustly detecting and delineating the arterial blood pressure (ABP) signal events. To meet this end, first, the original ABP signal is pre-processed by application of à trous discrete wavelet transform (DWT) for extracting several dyadic scales. Then, a fixed sample size sliding window is moved on the appropriately selected scale and in each slid, six features namely as summation of the nonlinearly amplified Hilbert transform, summation of absolute first-order differentiation, summation of absolute second-order differentiation, curve length, area and variance of the excerpted segment are calculated. Then, all feature trends are normalized and utilized to construct a newly proposed principal components analyzed geometric index (PCAGI) (to be used as the segmentation decision statistic (DS)) by application of a linear orthonormal projection. After application of an adaptive-nonlinear transformation for making the DS baseline stationary, the histogram parameters of the enhanced DS are used to regulate the α-level Neyman–Pearson classifier for false alarm probability (FAP)-bounded delineation of the ABP events. In order to illustrate the capabilities of the presented algorithm, it was applied to all 18 subjects of the MIT-BIH Polysomnographic Database (359,000 beats) and the end-systolic and end-diastolic locations of the ABP signal as well as dicrotic notch pressure were extracted and values of sensitivity and positive predictivity Se = 99.86% and P+ = 99.95% were obtained for the detection of all ABP events. High robustness against measurement noises, acceptable detection-delineation accuracy of the ABP events in the presence of severe heart valvular and arrhythmic dysfunctions within a tolerable computational burden (processing time) and having no parameters dependency to the acquisition sampling frequency can be mentioned as the important merits and capabilities of the proposed PCAGI-based ABP events detection-segmentation algorithm.
CONSTRUCTION OF COMPACTLY SUPPORTED WAVELETS FROM TRIGONOMETRIC B-SPLINES
Authors: JENA M. K.
Published: May 2011

We construct a class of semiorthogonal wavelets by taking a normalized trigonometric B-spline of any order as the scaling function. The construction is based on generalized Euler–Frobenius polynomial and generalized autocorrelation function. We also show that the odd order normalized trigonometric B-spline satisfies convex hull property as well as partition of unity property. Moreover, we also present a subdivision algorithm for the convolution of normalized trigonometric B-splines. Several examples of wavelet are also provided.
Pharyngeal airway protective reflexes are triggered before the maximum volume of fluid that the hypopharynx can safely hold is exceeded
Authors: Dua Kulwinder , Surapaneni Sri Naveen , Kuribayashi Shiko , Hafeezullah Muhammad , Shaker Reza
Published: May 2011

Aerodigestive reflexes triggered by pharyngeal stimulation can protect the airways by clearing fluid from the pharynx. The objective of this study was to determine the relationship between the maximum capacity of fluid that can safely dwell in the hypopharynx [hypopharyngeal safe volume (HPSV)] before spilling into the larynx and the threshold volumes required to trigger pharyngoglottal closure reflex (PGCR), pharyngo-upper esophageal sphincter contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS). Twenty-five healthy volunteers (mean age 24 yr, 8 males) were studied in the semi-inclined supine position. PGCR, PUCR, and RPS were elicited using techniques of concurrent upper esophageal sphincter manometry and pharyngo-laryngoscopy. The hypopharynx was then anesthetized to abolish RPS. HPSV was determined by infusing water in the pharynx, and perfusion was stopped when the infusate reached the superior margin of the interarytenoid fold. The threshold volumes for triggering PGCR, PUCR, and RPS by slow and rapid injections before pharyngeal anesthesia were 0.18 ± 0.02 and 0.09 ± 0.02 ml; 0.20 ± 0.020 and 0.13 ± 0.04 ml; and 0.61 ± 0.04 and 0.4 ± 0.06 ml, respectively. All of the above volumes were significantly smaller than the HPSV (0.70 ± 0.06 ml, P < 0.01) except for the threshold volume to elicit RPS during slow perfusion, which was not significantly different ( P = 0.23). We conclude that pharyngeal aerodigestive reflexes are triggered by both slow and rapid pharyngeal perfusion of water at significantly smaller volumes than the maximum capacity of the hypopharynx to safely hold contents without spilling into the airway. These reflexes thereby aid in prevention of aspiration.
Immunocytochemical evidence for PDBu-induced activation of RhoA/ROCK in human internal anal sphincter smooth muscle cells
Authors: Singh Jagmohan , Maxwell Pinckney J. , Rattan Satish
Published: May 2011

Studies were performed to determine the unknown status of PKC and RhoA/ROCK in the phorbol 12,13-dibutyrate (PDBu)-stimulated state in the human internal anal sphincter (IAS) smooth muscle cells (SMCs). We determined the effects of PDBu (10−7M), the PKC activator, on PKCα and RhoA and ROCK II translocation in the human IAS SMCs. We used immunocytochemistry and fluorescence microcopy in the basal state, following PDBu, and before and after PKC inhibitor calphostin C (10−6M), cell-permeable RhoA inhibitor C3 exoenzyme (2.5 μg/ml), and ROCK inhibitor Y 27632 (10−6M). We also determined changes in the SMC lengths via computerized digital micrometry. In the basal state PKCα was distributed almost uniformly throughout the cell, whereas RhoA and ROCK II were located in the higher intensities toward the periphery. PDBu caused significant translocation of PKCα, RhoA, and ROCK II. PDBu-induced translocation of PKCα was attenuated by calphostin C and not by C3 exoenzyme and Y 27632. However, PDBu-induced translocation of RhoA was blocked by C3 exoenzyme, and that of ROCK II was attenuated by both C3 exoenzyme and Y 27632. Contraction of the human IAS SMCs caused by PDBu in parallel with RhoA/ROCK II translocation was attenuated by C3 exoenzyme and Y 27632 but not by calphostin C. In human IAS SMCs RhoA/ROCK compared with PKC are constitutively active, and contractility by PDBu is associated with RhoA/ROCK activation rather than PKC. The relative contribution of RhoA/ROCK vs. PKC in the pathophysiology and potential therapy for the IAS dysfunction remains to be determined.
Does physical inactivity cause nonalcoholic fatty liver disease?
Authors: Rector R. Scott , Thyfault John P.
Published: May 2011

While physical activity represents a key element in the prevention and management of many chronic diseases, we and others believe that physical inactivity is a primary cause of obesity and associated metabolic disorders. Unfortunately, accumulating evidence suggests that we have engineered physical activity out of our normal daily living activity. One such consequence of our sedentary and excessive lifestyle is nonalcoholic fatty liver disease (NAFLD), which is now considered the most common cause of chronic liver disease in Westernized societies. In this review, we will present evidence that physical inactivity, low aerobic fitness, and overnutrition, either separately or in combination, are an underlying cause of NAFLD.
Synergistic Antitumor Activity of Gemcitabine and ABT-737 In Vitro and In Vivo through Disrupting the Interaction of USP9X and Mcl-1
Authors: Zhang Chong , Cai Tian-yu , Zhu Hong , Yang Liu-qing , Jiang Hai , Dong Xiao-wu , Hu Yong-zhou , Lin Neng-ming , He Qiao-jun , Yang Bo
Published: May 2011

The Bcl-2 antagonist ABT-737 targets Bcl-2/Bcl-xL, but not Mcl-1, which may confer resistance to this agent in various cancers with high levels of Mcl-1. Here, we showed that the combination of gemcitabine and ABT-737 exhibited synergistic cytotoxicity and induced significant apoptosis in multiple cancer types, including lung, renal, bladder, and prostate cancers. The enhanced apoptosis induced by gemcitabine plus ABT-737 was accompanied by the greater extent of mitochondrial depolarization, caspases-3 activation, and PARP cleavage in 95-D and 5637 cell lines. Importantly, in ABT-737–resistant cancer cells, the interaction between USP9X and Mcl-1, which was increased by ABT-737 treatment, could be disrupted by gemcitabine, thus resulting in enhanced ubiquitination and the subsequent degradation of Mcl-1 and ultimately in the synergism of these two drugs. Moreover, the increased anticancer efficacy of gemcitabine combined with ABT-737 was further validated in a human lung cancer 95-D xenograft model in nude mice. Taken together, our data first showed the synergistic anticancer capabilities achieved by combining gemcitabine and ABT-737 and, second, opened new opportunities to use antiapoptotic Bcl-2 family members, which drive tumor cell resistance in current anticancer therapies, therapeutically. Mol Cancer Ther; 10(7); 1264–75. ©2011 AACR.
The SCPP Gene Family and the Complexity of Hard Tissues in Vertebrates
Authors: Kawasaki Kazuhiko
Published: May 2011

Diverse hard tissues constituted a tooth-like skeletal element in extinct jawless vertebrates. Today, similar tissues are found in our teeth. These tissues mineralize in the extracellular matrix and involve various macromolecules. Among these molecules are secretory calcium-binding phosphoproteins (SCPPs) coded by genes that arose by duplication. Although the repertoire of SCPPs may vary in different lineages, some SCPPs are unusually acidic and are thought to participate in the mineralization of a collagenous matrix, principally either bone or dentin. Other SCPPs are rich in Pro and Gln (P/Q) and are employed to form the tooth surface. In tetrapods, the tooth surface is usually covered with enamel which develops in a matrix comprised of P/Q-rich SCPPs. By contrast, the tooth surface tissue in teleosts is called enameloid and it forms in a dentin-like collagenous matrix. Despite the difference in their matrix, both enamel and enameloid mature into hypermineralized inorganic tissues. Notably, some P/Q-rich SCPP genes are primarily expressed at this stage and their proteins localize between the tooth surface and overlying dental epithelium. Moreover, an orthologous gene is used for maturation of these 2 different tissues. These findings suggest distinct roles of acidic and P/Q-rich SCPPs during the evolution of hard tissues. Acidic SCPPs initially regulated the mineralization of bone, dentin, or a similar ancient collagenous tissue through interaction with calcium ions. P/Q-rich SCPPs arose next and originally assembled a structure or a space that facilitated the hypermineralization of dentin or a dentin-like tissue. Subsequently, some P/Q-rich SCPPs were coopted for the mineralizing enamel matrix. More recently, however, many SCPP genes were lost in toothless birds and mammals. Thus, it appears that, in vertebrates, the phenotypic complexity of hard tissues correlates with gain and loss of SCPP genes.
Crystallization Pathways in Bone
Authors: Mahamid Julia , Addadi Lia , Weiner Steve
Published: May 2011

Many biomineralization processes involve the sequestering of ions by cells and their translocation through the cells to the final deposition site. In many invertebrate crystallization pathways the cells deposit an initial highly disordered mineral phase with intracellular vesicles, and this mineral is subsequently transported into the final deposition site outside the cell. As this initial mineral phase is metastable, it can easily dissolve or crystallize during sample preparation and examination. A cryogenic electron microscopy study of the forming fin bone of a zebra fish strain with continuously growing fins shows that the cells responsible for bone tissue formation do have mineral-bearing intracellular vesicles and that the mineral phase is a highly disordered calcium phosphate. We also show that globules of disordered calcium phosphate are present in the extracellular collageneous matrix and that they are not membrane bound. Close to the mineralization front these globules appear to penetrate into the collagen fibrils where they crystallize to form mature bone. This crystallization pathway is similar to pathways observed in invertebrates, and it differs from the matrix vesicle pathway documented for a variety of vertebrate mineralizing tissues as the extracellular mineral globules are not membrane bound.
Osteopontin and Wound Healing in Bone
Authors: McKee Marc D. , Pedraza Claudio E. , Kaartinen Mari T.
Published: May 2011

Bone wound healing after surgical drilling/cutting initially involves a typical inflammatory response with a leukocyte-rich cell infiltrate whose professional phagocytes (neutrophils and macrophages) clear the wound site of various bacterial (if present), particulate, and insoluble components arising from the original wounding event. As part of this process, in a surgical model of bone repair in rats, osteopontin (OPN) secreted by macrophages – with its known mineral-binding properties arising from abundant calcium-binding phosphorylations and overall net negative charge – binds to the newly exposed mineralized surfaces of particulate bone debris and the osseous wound margins created by the drilling, as shown by high-resolution immunogold labeling and transmission electron microscopy. For bone debris powder, OPN serves as an opsonin for clearance by macrophage phagocytosis, as demonstrated in vitro by phagocytosis assays using cultured J774.A1 murine macrophages and OPN-coated microbeads. Macrophage-secreted OPN binding to the bone wound margins contributes to cement line (plane) formation with subsequent OPN additions to the cement line coming from osteoblast lineage cells arriving at this site to effect bone repair upon further osteoblast differentiation, and extracellular matrix deposition and mineralization. Such interfacial OPN is thought to contribute to the cell adhesion, cell signaling, and matrix mineralization events required to effectively integrate the new bone into the preexisting bone at the margins of the drill site.
Characterization of Oxidative Stress Status during Diabetic Bone Healing
Authors: Waddington Rachel J. , Alraies Amr , Colombo John S. , Sloan Alastair J. , Okazaki Joji , Moseley Ryan
Published: May 2011

Early events associated with bone healing in patients with type 2 diabetes mellitus appear to be delayed. Hyperglycaemia and an associated increase in oxidative stress are cited as potential factors leading to a change in cellular behaviour. Using an in vivo model monitoring bone formation around implants placed into rat mandibles, we have previously identified that the onset of cell proliferation and osteoblast differentiation are delayed and subsequently prolonged compared with normal bone. This study used the same implant model to characterize oxidative stress biomarkers and primary antioxidant enzyme profiles during diabetic bone healing in vivo. Implants were placed into the sockets of incisors extracted from the mandibles of normal Wistar and diabetic Goto-Kakizaki rats for 3 and 9 weeks after implant insertion. Histochemical analysis confirmed a delay in bone healing around implants in diabetic animals. Immunohistochemical localization of peri-cellular staining for protein carbonyl groups, as a biomarker of oxidized protein content, was slightly higher in diabetic granulation tissue compared with normal tissue. However, no differences were observed in the staining patterns of advanced glycation end products. Minimal differences were observed in the number of cells positive for cytoplasmic superoxide dismutase (SOD)1 or mitochondrial SOD2. Significantly, catalase was absent in diabetic tissues. The results suggest that the oxidative environment in healing bone is differentially affected by hyperglycaemia, particularly in relation to catalase. The significance of these observations for diabetic bone healing is discussed.
Dental Enamel Structure Is Altered by Expression of Dominant Negative RhoA in Ameloblasts
Authors: Li Yong , Pugach Megan K. , Kuehl Melissa A. , Peng Li , Bouchard Jessica , Hwang Soon Y. , Gibson Carolyn W.
Published: May 2011

Using in vitrotooth germ cultures and analysis by confocal microscopy, ameloblasts treated with sodium fluoride were found to have elevated amounts of filamentous actin. Because this response is reduced by inhibitors of the Rho/ROCK signaling pathway, we generated mice that express dominant negative RhoA (RhoADN) in ameloblasts for in vivo analysis. Expression of the EGFP-RhoADN fusion protein was evaluated by RT-PCR and immunohistochemistry, and teeth were analyzed by scanning electron microscopy. The 3 strains expressed at either low (TgEGFP-RhoADN-8), intermediate (TgEGFP-RhoADN-2), or high (TgEGFP-RhoADN-13) levels, and the molar teeth from the 3 strains had enamel hypoplasia and surface defects. We conclude that RhoADN expressed in ameloblasts interferes with normal enamel development through the pathway that is induced by sodium fluoride.
Restless Legs Syndrome in Multiple Sclerosis
Authors: Aydar Gülay , Kurt Semiha , Karaer Unaldi Hatice , Erkorkmaz Unal
Published: May 2011

Aims: Multiple sclerosis (MS) is a demyelinating neurodegenerative inflammatory autoimmune disease. Restless legs syndrome (RLS) is characterized as a strong urge to move the legs to stop abnormal sensations there. In this study, we aimed to investigate whether or not the increased RLS frequency seen in MS could be associated with depression and fatigue. Methods: The study involved 98 patients with definite MS and 129 healthy volunteers. The Beck Depression Inventory and Fatigue Severity Scale were used to assess all participants. The patients and the healthy volunteers were examined for RLS according to the criteria of the International Restless Legs Syndrome Study Group. Results: When the factors related to RLS in MS were evaluated, there were significant relationships found among age, type of MS, pyramidal symptoms, intestinal and bladder symptoms, number of lesions in MR, depression, and fatigue. Risk factors for RLS were also seen more frequently in the MS group than in the healthy volunteers. Conclusion: RLS was seen 2.55 times more frequently in patients with MS than in the control group. This was due to the existence of numerous factors rather than a single factor – including depression and fatigue.
The Corticotropin-Releasing Hormone Network and the Hypothalamic-Pituitary-Adrenal Axis: Molecular and Cellular Mechanisms Involved
Authors: Bonfiglio Juan José , Inda Carolina , Refojo Damián , Holsboer Florian , Arzt Eduardo , Silberstein Susana
Published: May 2011

Corticotropin-releasing hormone (CRH) plays a key role in adjusting the basal and stress-activated hypothalamic-pituitary-adrenal axis (HPA). CRH is also widely distributed in extrahypothalamic circuits, where it acts as a neuroregulator to integrate the complex neuroendocrine, autonomic, and behavioral adaptive response to stress. Hyperactive and/or dysregulated CRH circuits are involved in neuroendocrinological disturbances and stress-related mood disorders such as anxiety and depression. This review describes the main physiological features of the CRH network and summarizes recent relevant information concerning the molecular mechanism of CRH action obtained from signal transduction studies using cells and wild-type and transgenic mice lines. Special focus is placed on the MAPK signaling pathways triggered by CRH through the CRH receptor 1 that plays an essential role in CRH action in pituitary corticotrophs and in specific brain structures. Recent findings underpin the concept of specific CRH-signaling pathways restricted to specific anatomical areas. Understanding CRH action at molecular levels will not only provide insight into the precise CRH mechanism of action, but will also be instrumental in identifying novel targets for pharmacological intervention in neuroendocrine tissues and specific brain areas involved in CRH-related disorders.
A Novel Retrograde Laser Extraction Technique Using a Transatrial Approach
Authors: Rodriguez Yasser , Garisto Juan D. , Carrillo Roger G.
Published: May 2011

Background—

The use of percutaneous lead extraction techniques in a patient with extracardiac or protruding atrial leads could have disastrous consequences. Traditionally, the management of these patients has included a median sternotomy. We describe a minimally invasive technique that involves a transatrial, retrograde laser lead extraction using a video-assisted thoracoscopic approach.

Methods and Results—

Between January 2004 and June 2009, 14 patients with severed leads at the clavicle and extracardiac leads or lead-caused erosions of the atrial wall were identified through chest radiograph and CT scan. There were 9 men and 5 women aged 19 to 91 years (mean age, 69.71±20.67 years). Ten devices were pacemakers, and 4 were defibrillators. Indications for extraction were 12 infections and 2 malfunctions. Mean ejection fraction was 42±17.67% (range, 10% to 65%). Time of implanted leads was 93.69±51.88 months (range, 33 to 213 months). Laser sheaths size were 12 F (7.1%), 14 F (85.7%), and 16 F (7.1%). A right-side thoracoscopy was performed under general anesthesia. A retrograde laser sheath maneuver was performed, freeing the lead from any adhesions. The lead was removed and the incision closed. One patient experienced a pleural effusion. There was no mortality, and all patients were alive and well at 1-month follow-up.

Conclusions—

Transatrial, retrograde laser lead extraction is a safe and effective procedure. This procedure may provide an excellent alternative to open sternotomy.
Common Variants in Epithelial Sodium Channel Genes Contribute to Salt Sensitivity of Blood Pressure
Authors: Zhao Qi , Gu Dongfeng , Hixson James E. , Liu De-Pei , Rao Dabeeru C. , Jaquish Cashell E. , Kelly Tanika N. , Lu Fanghong , Ma Jixiang , Mu Jianjun , Shimmin Lawrence C. , Chen Jichun , Mei Hao , Hamm L. Lee , He Jiang ,   for the Genetic Epidemiology Network of Salt Sensitivity Collaborative Research Group
Published: May 2011

Background—

Rare mutations of the epithelial sodium channel (ENaC) lead to mendelian forms of salt-sensitive hypertension or salt-wasting hypotension. We aimed to examine the association between common variants in the ENaC genes and salt sensitivity of blood pressure (BP).

Methods and Results—

A total of 1906 Han Chinese participated in the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) study, which includes a 7-day low-sodium intake (51.3 mmol sodium/d) followed by a 7-day high-sodium intake (307.8 mmol sodium/d). Nine BP measurements were obtained at baseline and each intervention period using a random-zero sphygmomanometer. Single-nucleotide polymorphisms, both tagging and functional, from the 3 ENaC subunits, α, β, and γ (
SCNN1A, SCNN1B
, and
SCNN1G
), were genotyped. Multiple common single-nucleotide polymorphisms in
SCNN1G
were significantly associated with BP response to low-sodium intervention (rs4073930,
P
=1.7×10
−5
; rs4073291,
P
=1.1×10
−5
; rs7404408,
P
=1.9×10
−5
; rs5735,
P
=3.0×10
−4
; rs4299163,
P
=0.004; and rs4499238,
P
=0.002) even after correcting for multiple testing. For example, under an additive model, the minor allele G of SNP rs4073291 was associated with 1.33 mm Hg lower systolic BP reduction during low-sodium intervention.

Conclusions—

This large dietary sodium intervention study indicates that common variants of ENaC subunits may contribute to the variation of BP response to dietary sodium intake. Future studies are warranted to confirm these findings in an independent population and to identify functional variants for salt sensitivity.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00721721.
Changes in Ion Channel Gene Expression Underlying Heart Failure-Induced Sinoatrial Node Dysfunction
Authors: Yanni Joseph , Tellez James O. , Mączewski Michal , Mackiewicz Urszula , Beresewicz Andrzej , Billeter Rudi , Dobrzynski Halina , Boyett M.R.
Published: May 2011

Background—

Heart failure (HF) causes a decline in the function of the pacemaker of the heart—the sinoatrial node (SAN). The aim of the study was to investigate HF-induced changes in the expression of the ion channels and related proteins underlying the pacemaker activity of the SAN.

Methods and Results—

HF was induced in rats by the ligation of the proximal left coronary artery. HF animals showed an increase in the left ventricular (LV) diastolic pressure (317%) and a decrease in the LV systolic pressure (19%) compared with sham-operated animals. They also showed SAN dysfunction wherein the intrinsic heart rate was reduced (16%) and the corrected SAN recovery time was increased (56%). Quantitative polymerase chain reaction was used to measure gene expression. Of the 91 genes studied during HF, 58% changed in the SAN, although only 1% changed in the atrial muscle. For example, there was an increase in the expression of ERG, K
v
LQT1, K
ir
2.4, TASK1, TWIK1, TWIK2, calsequestrin 2, and the A1 adenosine receptor in the SAN that could explain the slowing of the intrinsic heart rate. In addition, there was an increase in Na
+
-H
+
exchanger, and this could be the stimulus for the remodeling of the SAN.

Conclusions—

SAN dysfunction is associated with HF and is the result of an extensive remodeling of ion channels; gap junction channels; Ca
2+
-, Na
+
-, and H
+
-handling proteins; and receptors in the SAN.
Effects of Neural Progenitor Cells on Sensorimotor Recovery and Endogenous Repair Mechanisms After Photothrombotic Stroke
Authors: Minnerup Jens , Kim Jeong Beom , Schmidt Antje , Diederich Kai , Bauer Henrike , Schilling Matthias , Strecker Jan-Kolja , Ringelstein E. Bernd , Sommer Clemens , Schöler Hans R. , Schäbitz Wolf-Rüdiger
Published: May 2011

Background and Purpose—

Intravenous neural progenitor cell (NPC) treatment was shown to improve functional recovery after experimental stroke. The underlying mechanisms, however, are not completely understood so far. Here, we investigated the effects of systemic NPC transplantation on endogenous neurogenesis and dendritic plasticity of host neurons.

Methods—

Twenty-four hours after photothrombotic ischemia, adult rats received either 5 million NPC or placebo intravenously. Behavioral tests were performed weekly up to 4 weeks after ischemia. Endogenous neurogenesis, dendritic length, and dendritic branching of cortical pyramid cells and microglial activation were quantified.

Results—

NPC treatment led to a significantly improved sensorimotor function measured by the adhesive removal test. The dendritic length and the amount of branch points were significantly increased after NPC transplantation, whereas endogenous neurogenesis was decreased compared to placebo therapy. Decreased endogenous neurogenesis was associated with an increased number of activated microglial cells.

Conclusions—

Our findings suggest that an increased dendritic plasticity might be the structural basis of NPC-induced functional recovery. The decreased endogenous neurogenesis after NPC treatment seems to be mediated by microglial activation.
Clinical Relevance of Improved Microbleed Detection by Susceptibility-Weighted Magnetic Resonance Imaging
Authors: Goos Jeroen D.C. , van der Flier Wiesje M. , Knol Dirk L. , Pouwels Petra J.W. , Scheltens Philip , Barkhof Frederik , Wattjes Mike P.
Published: May 2011

Background and Purpose—

Susceptibility-weighted imaging (SWI) has been shown to be more sensitive in detecting cerebral microbleeds (MBs) than is conventional T2*-weighted gradient-recalled echo imaging (GRE). However, the clinical relevance of this improved detection in terms of associations with clinical measures and risk factors is unclear. We sought to determine whether associations of MBs with clinical characteristics, risk factors, white-matter hyperintensities, and lacunes were different on GRE versus SWI in memory clinic patients.

Methods—

One hundred forty-one patients presenting at our memory clinic were included and underwent clinical evaluation and a magnetic resonance imaging protocol including both GRE and SWI. Images were analyzed for numbers and locations of MBs and white-matter hyperintensities. In a subset of patients, apolipoprotein E status was determined. Negative binomial regression was used to assess clinical and radiologic associations with MB number.

Results—

MB prevalence was 23% on GRE and 40% on SWI. A total of 219 and 284 MBs were detected on GRE and SWI, respectively. Within groups with MBs, the median MB count was 1 (range, 1 to 144) on GRE and 2 (range, 1 to 129) on SWI (
P
<0.001). The increase in the number of MBs on SWI was equally distributed among brain regions. Strengths of the associations with age, sex, white-matter hyperintensities, and presence of lacunes with higher MB numbers were comparable for GRE and SWI (all
P
<0.05); no differential independent associations were detected.

Conclusions—

SWI detected more MBs in more patients, irrespective of MB location. However, this enhanced detection had no improved clinical relevance in terms of associations with vascular risk factors or radiologic markers of small-vessel disease.