bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecological adaptation of weed biodiversity to the allelopathic rank of the stubble of different wheat genotypes in a maize field
Authors: ZUO SHENGPENG , MA YONGQING , SHINOBU INANAGA
Published: July 2008

The objective of this study was to integrate allelopathic bioassay and point sampling methods to investigate the allelopathic rank of the stubble of different wheat genotypes and its effect on weed biodiversity in a maize field. The study consisted of 17 wheat stubble treatments derived from ten wheat genotypes planted individually (monoculture) or in pairs (mixed culture). The maize was planted in the plots immediately following the wheat harvest and the number of weed species, total weed number, weed density, weed height, and weed cover were determined 50 days later. The results indicate a significant rank effect of allelopathic potential in the stubble of the different wheat genotypes. There was a stronger allelopathic effect from the straw in the mixed‐culture treatments compared to the monoculture treatments. Acalypha australis and Setaria viridis were the dominant weed species in the maize fields. The regression analysis shows that the weed biodiversity indices were significantly related to the allelopathic rank. The allelopathic potential exhibited spatial heterogeneity in all the scales, which would trigger resource heterogeneity and change the microhabitat conditions. Therefore, weed biodiversity would respond spatially and biologically to the heterogeneous distribution of allelochemicals from the wheat stubble. The allelopathic rank of the wheat stubble would lead to changes in weed biodiversity by regulating the ecological niche of the weed population. The weeds showed resistance or an adaptive response to exterior pressure, including allelopathic pressure. This study on the effect of allelopathic potential on weed biodiversity provides a solid theoretical basis for sustainable weed management of agro‐ecosystems.
Tillage implement effects on herbicide efficacy and the yield of cotton grown under a sprinkler or drip irrigation system
Authors: PAPAGEORGIOU IOANNIS , ELEFTHEROHORINOS ILIAS , VASILAKOGLOU IOANNIS
Published: July 2008

Field experiments were conducted during 2003 and 2004 at four locations in northern Greece to evaluate the effects of tillage implements and herbicide treatments on the weed control and yield of cotton grown under a mobile sprinkler or drip irrigation system. The tillage implements consisted of three seedbed preparation tillage implements: a field cultivator with a double rolling basket, a disk harrow or a rotary harrow. The herbicide treatments consisted of a broadcast preplant‐incorporated (PPI) application of trifluralin or S‐metolachlor followed by pre‐emergence (PRE)‐applied prometryn, a PRE 38 cm band application of S‐metolachlor plus fluometuron or a broadcast PPI application of S‐metolachlor followed by early postemergence‐applied trifloxysulfuron‐sodium. In most cases, the PPI applications followed by the PRE application of prometryn resulted in the greatest control of black nightshade (Solanum nigrum L.), redroot pigweed (Amaranthus retroflexus L.), and common lambsquarters (Chenopodium album L.). The control of black nightshade and common lambsquarters was slightly reduced when the herbicides were incorporated by rotary harrow. The cotton yield was not affected in most cases by the tillage implements, while the drip irrigation system provided a greater or similar cotton yield as compared with the sprinklers. The PPI application of trifluralin followed by the PRE‐applied prometryn in the cotton grown under drip irrigation provided the greatest lint yield in most cases. Therefore, a drip irrigation system and disk harrow or field cultivator implement could be used as the first choice of cotton growers in integrated crop management production systems.
Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data
Authors: Balke Michael , Ribera Ignacio , Beutel Rolf , Viloria Angel , Garcia Mauricio , Vogler Alfried P
Published: July 2008

The family Meruidae has been established recently for the newly discovered species Meru phyllisae Spangler & Steiner, 2005 from Southern Venezuela. These beetles are morphologically highly distinct and at a body length of 0.8 mm represent the perhaps smallest individuals of Adephaga. Here, we use DNA sequence data to place this enigmatic taxon relative to other aquatic groups in this suborder. Meruidae was most closely associated with Noteridae, supporting a previous analysis of morphological structures which had suggested this sister relationship, albeit with weak support. While different alignment strategies did not affect the topology, the precise placement of Meruidae was affected by the choice of tree reconstruction method. Bayesian inference suggests a sister relationship of Meruidae + Noteridae, while parsimony analyses retrieve Meruidae + Notomicrus (a basal noterid genus), which combined are the sister group of all remaining Noteridae. Considering morphological evidence, the former placement appears more plausible.
A phylogenetic perspective on 160 years of troubled taxonomy of Niphargus (Crustacea: Amphipoda)
Authors: Fišer Cene , Sket Boris , Trontelj Peter
Published: July 2008

Niphargus is the largest genus of freshwater amphipods. Its systematics from the species to the family level has always been problematic. This study is the first comprehensive phylogenetic treatment of the chiefly subterranean group in 160 years of its taxonomic history. It includes 103 niphargid species plus outgroups, representing about one‐third of all nominal species. The samples originated mainly from type localities or adjacent sites and covered most of the morphological variability of the genus. Character sampling included nuclear 28S and mitochondrial 12S rDNA sequences, and 122 morphological characters. Quantitative morphological traits were coded using two alternative methods. The first one searches for gaps in the variability range of each character, while the second one uses absolute differences between the standardized raw data as weights. Different data sets yielded alternative topologies. All data support the monophyly of Niphargidae, while Niphargopsis— another niphargid genus — was consistently nested within Niphargus, loosing justification for its separate status. We predict a similar fate for all or most of the remaining six small niphargid genera, which were not yet scrutinized phylogenetically. Different topologies agreed in species composition of five large, well‐supported clades, although the hierarchic relationships between them remain unresolved. These clades reject all previously proposed taxonomic subdivisions of Niphargus, implying a high degree of morphological homoplasy that renders any morphology‐based groups questionable. The clade members are distributed within well‐established zoogeographical regions that do not exceed 1300 km across the longest diagonal. These results provide a framework for future studies on niphargid systematics, the evolution of endemism and cryptic diversity in subterranean environments, the mechanisms leading to exceptional morphological heterogeneity, historical biogeography, and applied ecological issues.
Multinational Corporations and Patterns of Local Knowledge Transfer in Costa Rican High‐Tech Industries
Authors: Giuliani Elisa
Published: July 2008

Over recent decades, governments in industrializing countries have promoted policies to attract foreign investors, anticipating the benefits of technology transfer to host economies. During the 1990s, Costa Rica adopted an industrialization strategy based on attracting high‐tech multinational companies (MNCs). Using an original survey of a sample of high‐tech MNC subsidiaries, this article shows that the new wave of efficiency‐seeking subsidiaries tend not to transfer knowledge to domestic firms even when they establish backward linkages with them. Instead, most of the knowledge transfer occurs between high‐tech foreign subsidiaries. This has clear policy implications for host country governments.
Bridging the Social and Digital Divides in Andhra Pradesh and Kerala: A Capabilities Approach
Authors: Thomas Jayan Jose , Parayil Govindan
Published: July 2008

Combining empirical evidence with Amartya Sen's concept of capabilities, this article argues that the digital divide is not merely a problem of access to ICTs. It is part of a larger developmental problem in which vast sections of the world's population are deprived of the capabilities to use ICTs, acquire information and convert information into useful knowledge. Fieldwork research including sample surveys conducted in rural locations in Kerala and Andhra Pradesh in India shows that these capabilities can only be created through large‐scale complementary interventions in economic and social development.
Possibilism: An Approach to Problem‐Solving Derived from the Life and Work of Albert O. Hirschman
Authors: Lepenies Philipp H.
Published: July 2008

Albert O. Hirschman is the author of seminal, but prima facie unconnected contributions to the social sciences (‘exit–voice’, ‘linkages’). Yet, his main originality lies in his general approach to problem‐solving which is hidden behind the complexity of hisoeuvre. This article intends to disentangle the intricacies of his work and to reveal his specific mode of investigation by making the multifaceted biographical influences on Hirschman's scholarly writings visible. Exhibiting the influence that decisive moments in his life had on his work not only allows us to identify and define his method of ‘possibilism’: it also shows that this approach remains a valid and useful multidisciplinary tool for unorthodox contemporary social analysis.
MUNICIPAL CONTRACTING OUT: GOVERNANCE CHOICES, MISALIGNMENT AND PERFORMANCE IN SWEDISH LOCAL GOVERNMENT
Authors: Johansson Tobias
Published: July 2008

In this paper we apply a Transaction Cost Theory framework to analyse the use and effects of contracting out in Swedish local government. During the last decade Swedish local authorities, like in many other countries, have, to a larger extent, started to contract external subcontractors to fulfil their responsibilities towards its citizens. It is not only in the traditional subcontracting sectors such as housing, infrastructure, and technical services that this trend is evident, but also in policy areas like education, social care, and elderly care. In fact, very little is known about the overall effects of, and the mechanisms underlying, governance choices. The overall results corroborate transaction cost reasoning. Supplier competition and specificity have anticipated effects on municipal de‐integration. Too little, but not too much, use of contracting out, in relation to theoretical predictions, worsens performance. The latter aspect is not fully in accordance with TCE‐propositions.
IDENTIFYING THE MODERATOR FACTORS OF FINANCIAL PERFORMANCE IN GREEK MUNICIPALITIES
Authors: Cohen Sandra
Published: July 2008

The use of financial ratios is a widespread method for assessing the financial performance of private sector companies. However, the application of an analogous exercise in the public sector is a less straightforward one. In the later case it is a multifaceted task that involves judgments about the interplay of complex social, organizational and financial factors. In this paper we use accrual end of the year financial statements data of Greek Municipalities for the period 2002–2004 to compute nine commonly used performance assessment financial ratios. We find corroborative evidence that factors, which are exogenous to the municipalities’ control, such as their wealth and size, have statistically significant impact on ratio values. Thus, as financial ratios are significantly influenced by socio‐economic factors like municipal wealth and size, cross sectional comparisons on the basis of these ratios should be made with caution and performed for municipalities that exhibit similarities in terms of size and wealth.
LINKING COMPREHENSIVE PERFORMANCE ASSESSMENT TO THE BALANCED SCORECARD: EVIDENCE FROM HERTFORDSHIRE COUNTY COUNCIL
Authors: Woods Margaret , Grubnic Suzana
Published: July 2008

Over the course of the last twenty years there has been a growing academic interest in performance management, particularly in respect of the evolution of new techniques and their resulting impact. One important theoretical development has been the emergence of multidimensional performance measurement models that are potentially applicable within the public sector. Empirically, academic researchers are increasingly supporting the use of such models as a way of improving public sector management and the effectiveness of service provision (Mayston, 1985; Pollitt, 1986; Bates and Brignall, 1993; and Massey, 1999). This paper seeks to add to the literature by using both theoretical and empirical evidence to argue that CPA, the external inspection tool used by the Audit Commission to evaluate local authority performance management, is a version of the Balanced Scorecard which, when adapted for internal use, may have beneficial effects. After demonstrating the parallels between the CPA framework and Kaplan and Norton's public sector Balanced Scorecard (BSC), we use a case study of the BSC based performance management system in Hertfordshire County Council to demonstrate the empirical linkages between a local scorecard and CPA. We conclude that CPA is based upon the BSC and has the potential to serve as a springboard for the evolution of local authority performance management systems.
Subsidizing Technological Innovations in the Presence of R&D Spillovers
Authors: Helm Carsten , Schöttner Anja
Published: July 2008

We analyze a situation where a principal wants to induce two firms to produce an output, for example electricity from renewable energy sources. Firms can undertake non-contractible investments to reduce production cost of the output. Part of these investments spills over and also reduces production cost of the other firm. Comparing a general price subsidy and an innovation tournament, we find that the principal’s expected cost of implementing a given expected output is always higher under the tournament, even though this scheme may lead to more innovation.
On the Competition of Asymmetric Agents
Authors: Harbring Christine , Lünser Gabriele K.
Published: July 2008

Rank-order tournaments are usually implemented in organizations to provide incentives for eliciting employees’ effort and/or to identify the agent with the higher ability, for example in promotion tournaments. We close a gap in the literature by experimentally analyzing a ceteris paribus variation of the prize spread - being the major design feature of tournaments - in a symmetric and an asymmetric setting. We find that effort significantly increases with the prize spread as predicted by standard theory. However, only for sufficiently large prize spreads weak players competing against strong players strain themselves all the more and sorting of agents is feasible.
Temporal profiling of changes in phosphatidylinositol 4,5‐bisphosphate, inositol 1,4,5‐trisphosphate and diacylglycerol allows comprehensive analysis of phospholipase C‐initiated signalling in single neurons1
Authors: Nelson Carl P. , Nahorski Stefan R. , Challiss R. A. John
Published: July 2008

Phosphatidylinositol 4,5‐bisphosphate (PIP2) fulfils vital signalling roles in an array of cellular processes, yet until recently it has not been possible selectively to visualize real‐time changes in PIP2 levels within living cells. Green fluorescent protein (GFP)‐labelled Tubby protein (GFP‐Tubby) enriches to the plasma membrane at rest and translocates to the cytosol following activation of endogenous Gαq/11‐coupled muscarinic acetylcholine receptors in both SH‐SY5Y human neuroblastoma cells and primary rat hippocampal neurons. GFP‐Tubby translocation is independent of changes in cytosolic inositol 1,4,5‐trisphosphate and instead reports dynamic changes in levels of plasma membrane PIP2. In contrast, enhanced GFP (eGFP)‐tagged pleckstrin homology domain of phospholipase C (PLCδ1) (eGFP‐PH) translocation reports increases in cytosolic inositol 1,4,5‐trisphosphate. Comparison of GFP‐Tubby, eGFP‐PH and the eGFP‐tagged C12 domain of protein kinase C‐γ [eGFP‐C1(2); to detect diacylglycerol] allowed a selective and comprehensive analysis of PLC‐initiated signalling in living cells. Manipulating intracellular Ca2+ concentrations in the nanomolar range established that GFP‐Tubby responses to a muscarinic agonist were sensitive to intracellular Ca2+ up to 100–200 nM in SH‐SY5Y cells, demonstrating the exquisite sensitivity of agonist‐mediated PLC activity within the range of physiological resting Ca2+ concentrations. We have also exploited GFP‐Tubby selectively to visualize, for the first time, real‐time changes in PIP2 in hippocampal neurons.
Intracellular signaling pathways involved in post‐mitotic dopaminergic PC12 cell death induced by 6‐hydroxydopamine
Authors: Rodriguez‐Blanco Jezabel , Martín Vanesa , Herrera Federico , García‐Santos Guillermo , Antolín Isaac , Rodriguez Carmen
Published: July 2008

Oxidative stress has been shown to mediate neuron damage in Parkinson’s disease (PD). In the present report, we intend to clarify the intracellular pathways mediating dopaminergic neuron death after oxidative stress production using post‐mitotic PC12 cells treated with the neurotoxin 6‐hydroxydopamine (6‐OHDA). The use of post‐mitotic cells is crucial, because one of the suggested intracellular pathways implicated in neuron death relates to the re‐entry of neurons (post‐mitotic cells) in the cell cycle. We find that 6‐OHDA sequentially increases intracellular oxidants, functional cell damage and caspase‐3 activation, leading to cell death after 12 h of incubation. Prevention of cell damage by different antioxidants supports the implication of oxidative stress in the observed neurotoxicity. Oxidative stress‐dependent phosphorylation of the MAPK JNK and oxidative stress‐independent PKB/Akt dephosphorylation are involved in 6‐OHDA neurotoxicity. Decrease in p21WAF1/CIP1and cyclin‐D1 expression, disappearance of the non‐phosphorylated band of retinoblastoma protein (pRb), and expression of proliferating cell nuclear antigen, not present in PC12 post‐mitotic cells, suggest a re‐entry of differentiated cells into cell cycle. Our results indicate that such a re‐entry is mediated by oxidative stress and is involved in 6‐OHDA‐induced cell death. We conclude that at least three intracellular pathways are involved in 6‐OHDA‐induced cell death in differentiated PC12 cells: JNK activation, cell cycle progression (both oxidative stress‐dependent), and Akt dephosphorylation (not related to the increase of oxidants); the three pathways are necessary for the cells to die, since blocking one of them is sufficient to keep the cells alive.
Mesenchymal stem cells therapy exerts neuroprotection in a progressive animal model of Parkinson’s disease
Authors: Park Hyun Jung , Lee Phil Hyu , Bang Oh Young , Lee Gwang , Ahn Young Hwan
Published: July 2008

Parkinson’s disease is a common progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra. We investigated whether cell therapy with human mesenchymal stem cells (hMSCs) had a protective effect on progressive dopaminergic neuronal loss in vitro and in vivo. In primary mesencephalic cultures, hMSCs treatment significantly decreased MG‐132‐induced dopaminergic neuronal loss with a significant reduction of caspase‐3 activity. In rats received systemic injection of MG‐132, hMSCs treatment in MG‐132‐treated rats dramatically reduced the decline in the number of tyrosine hydroxylase (TH)‐immunoreactive cells, showing an approximately 50% increase in the survival of TH‐immunoreactive cells in the substantia nigra compared with the MG‐132‐treated group. Additionally, hMSC treatment significantly decreased OX‐6 immunoreactivity and caspase‐3 activity. Histological analysis showed that the number of NuMA‐positive cells was 1.7% of total injected hMSCs and 35.7% of these cells were double‐stained with NuMA and TH. Adhesive‐removal test showed that hMSCs administration in MG‐132‐treated rats had a tendency to decrease in the mean removal time. This study demonstrates that hMSCs treatment had a protective effect on progressive loss of dopaminergic neurons induced by MG‐132 in vitro and in vivo. Complex mechanisms mediated by trophic effects of hMSCs and differentiation of hMSCs into functional TH‐immunoreactive neurons may work in the neuroprotective process.
Direct coloration of textiles with photochromic dyes. Part 2: The effect of solvents on the colour change of photochromic textiles†
Authors: Billah Shah M Reduwan , Christie Robert M , Morgan Keith M
Published: July 2008

Polyester, acrylic and nylon textile substrates dyed with two spirooxazine dyes, 1,3,3‐trimethyl‐spiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine (1a) and 6′‐piperidino‐1,3,3‐trimethyl spiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine (1b), exhibit significantly higher photochromic colour build‐up when wet compared with after drying. A study of this phenomenon, extended beyond water to the influence of a series of selected organic solvents on photochromic behaviour, using colour measurement of the photochromic textiles under controlled ultraviolet irradiation conditions, is reported. The results of molecular modelling calculations (AM1 in water and PM5 in water) have been used as a means of interpreting the observed effects, in conjunction with qualitative arguments based on solvation and fibre swelling.
Preserving Population Allele Frequencies in Ex Situ Conservation Programs
Authors: SAURA MARÍA , PÉREZ‐FIGUEROA ANDRÉS , FERNÁNDEZ JESÚS , TORO MIGUEL A. , CABALLERO ARMANDO
Published: July 2008

Abstract: Optimization of contributions of parents to progeny by minimizing the average coancestry of the progeny is an effective strategy for maintaining genetic diversity in ex situ conservation programs, but its application on the basis of molecular markers has the negative collateral effect of homogenizing the allelic frequencies at each locus. Because one of the objectives of a conservation program is to preserve the genetic composition of the original endangered population, we devised a method in which markers are used to maintain the allele frequency distribution at each locus as closely as possible to that of the native population. Contributions of parents were obtained so as to minimize changes in allele frequency for a set of molecular markers in a population of reduced size. We used computer simulations, under a range of scenarios, to assess the effectiveness of the method in comparison with methods in which contributions of minimum coancestry are sought, either making use of molecular markers or genealogical information. Our simulations indicated that the proposed method effectively maintained the original distribution of allele frequencies, particularly under strong linkage, and maintained acceptable levels of genetic diversity in the population. Nevertheless, contributions of minimum coancestry determined from pedigree information but ignoring the genealogy previous to the conservation program, was the most effective method for maintaining allelic frequencies in realistic situations.
Bayesian Reanalysis of the Challenger O‐Ring Data
Authors: Maranzano Coire J. , Krzysztofowicz Roman
Published: July 2008

A Bayesian forecasting model is developed to quantify uncertainty about the postflight state of a field‐joint primary O‐ring (not damaged or damaged), given the O‐ring temperature at the time of launch of the space shuttle Challenger in 1986. The crux of this problem is the enormous extrapolation that must be performed: 23 previous shuttle flights were launched at temperatures between 53 °F and 81 °F, but the next launch is planned at 31 °F. The fundamental advantage of the Bayesian model is its theoretic structure, which remains correct over the entire sample space of the predictor and that affords flexibility of implementation. A novel approach to extrapolating the input elements based on expert judgment is presented; it recognizes that extrapolation is equivalent to changing the conditioning of the model elements. The prior probability of O‐ring damage can be assessed subjectively by experts following a nominal‐interacting process in a group setting. The Bayesian model can output several posterior probabilities of O‐ring damage, each conditional on the given temperature and on a different strength of the temperature effect hypothesis. A lower bound on, or a value of, the posterior probability can be selected for decision making consistently with expert judgment, which encapsulates engineering information, knowledge, and experience. The Bayesian forecasting model is posed as a replacement for the logistic regression and the nonparametric approach advocated in earlier analyses of the Challenger O‐ring data. A comparison demonstrates the inherent deficiency of the generalized linear models for risk analyses that require (1) forecasting an event conditional on a predictor value outside the sampling interval, and (2) combining empirical evidence with expert judgment.
Slogans and graffiti: Postmemory among youth in the Italo–Slovenian borderland
Authors: MIKLAVCIC ALESSANDRA
Published: July 2008

In this article, I look at the ways in which contested memories, imagined communities, and social ressentiment are embraced and filtered by Slovenian and Italian youth as postmemory and transformed into symbolic weapons that exclude, make demands, or simply provoke. Drawing on fieldwork conducted in the Italo–Slovenian border area of Trieste, I analyze two settings in which these symbols are used: a soccer match between Slovenia and Italy played in the summer of 2002 at which a mysterious banner provoked diplomatic tensions and the everyday graffiti war waged on the walls of the city of Trieste. [political symbols, memories, youth, Italy, Slovenia, soccer match, graffiti]
Abnormal connexin43 in arrhythmogenic right ventricular cardiomyopathy caused by plakophilin‐2 mutations
Authors: Fidler Lee M. , Wilson Gregory J. , Liu Fanfan , Cui Xuezhi , Scherer Stephen W. , Taylor Glenn P. , Hamilton Robert M.
Published: July 2008

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disorder of cardiomyocyte intercalated disk proteins causing sudden death. Heterozygous mutations of the desmosomal protein plakophilin‐2 (PKP‐2) are the commonest genetic cause of ARVC. Abnormal gap junction connexin43 expression has been reported in autosomal dominant forms of ARVC (Naxos and Carvajal disease) caused by homozygous mutations of desmosomal plakoglobin and desmoplakin. In tissue culture, suppression of PKP‐2 results in decreased expression of connexin43. We sought to characterize the expression and localization of connexin43 in patients with ARVC secondary to heterozygous PKP‐2 mutations. Complete PKP‐2 gene sequencing of 27 ARVC patients was utilized to identify mutant genotypes. Endomyocardial biopsies of identified carriers were then assessed by immunofluorescence to visualize intercalated disk proteins. N‐cadherin was targeted to highlight intercalated disks, followed by counterstaining for PKP‐2 or connexin43 using confocal double immunofluorescence microscopy. Immunofluorescence was quantified using an Adobe® Photoshop protocol, and colocalization coefficients were determined. PKP‐2 siRNA experiments were performed in mouse cardiomyocyte (HL1) cell culture with Western blot analysis to assess connexin43 expression following PKP‐2 suppression. Missense and frameshift mutations of the PKP‐2 gene were found in four patients with biopsy material available for analysis. Immunofluorescent studies showed PKP‐2 localization to the intercalated disk despite mutations, but associated with decreased connexin43 expression and abnormal colocalization. PKP‐2 siRNA in HL1 culture confirmed decreased connexin43 expression. Reduced connexin43 expression and localization to the intercalated disk occurs in heterozygous human PKP‐2 mutations, potentially explaining the delayed conduction and propensity to develop arrhythmias seen in this disease.
Features of cardiomyocyte proliferation and its potential for cardiac regeneration
Authors: van Amerongen Machteld J. , Engel Felix B.
Published: July 2008

The human heart does not regenerate. Instead, following injury, human hearts scar. The loss of contractile tissue contributes significantly to morbidity and mortality. In contrast to humans, zebrafish and newts faithfully regenerate their hearts. Interestingly, regeneration is in both cases based on cardiomyocyte proliferation. In addition, mammalian cardiomyocytes proliferate during foetal development. Their proliferation reaches its maximum around chamber formation, stops shortly after birth, and subsequent heart growth is mostly achieved by an increase in cardiomyocyte size (hypertrophy). The underlying mechanisms that regulate cell cycle arrest and the switch from proliferation to hypertrophy are unclear. In this review, we highlight features of dividing cardiomyocytes, summarize the attempts to induce mammalian cardiomyocyte proliferation, critically discuss methods commonly used for its detection, and explore the potential and problems of inducing cardiomyocyte proliferation to improve function in diseased hearts.
Sonic hedgehog regulates angiogenesis and myogenesis during post‐natal skeletal muscle regeneration
Authors: Straface Giuseppe , Aprahamian Tamar , Flex Andrea , Gaetani Eleonora , Biscetti Federico , Smith Roy C. , Pecorini Giovanni , Pola Enrico , Angelini Flavia , Stigliano Egidio , Castellot Jr. John J. , Losordo Douglas W. , Pola Roberto
Published: July 2008

Sonic hedgehog (Shh) is a morphogen‐regulating crucial epithelial‐mesenchymal interactions during embryonic development, but its signalling pathway is considered generally silent in post‐natal life. In this study, we demonstrate that Shh is de novo expressed after injury and during regeneration of the adult skeletal muscle. Shh expression is followed by significant up‐regulation of its receptor and target gene Ptc1 in injured and regenerating muscles. The reactivation of the Shh signalling pathway has an important regulatory role on injury‐induced angiogenesis, as inhibition of Shh function results in impaired up‐regulation of prototypical angiogenic agents, such as vascular endothelial growth factor (VEGF) and stromal‐derived factor (SDF)‐1alpha, decreased muscle blood flow and reduced capillary density after injury. In addition, Shh reactivation plays a regulatory role on myogenesis, as its inhibition impairs the activation of the myogenic regulatory factors Myf‐5 and MyoD, decreases the up‐regulation of insulin‐like growth factor (IGF)‐1 and reduces the number of myogenic satellite cells at injured site. Finally, Shh inhibition results in muscle fibrosis, increased inflammatory reaction and compromised motor functional recovery after injury. These data demonstrate that the Shh pathway is functionally important for adult skeletal muscle regeneration and displays pleiotropic angiogenic and myogenic potentials in post‐natal life. These findings might constitute the foundation for new therapeutic approaches for muscular diseases in humans.
A pilot study of research utilization practices and critical thinking dispositions of Alberta dental hygienists
Authors: Cobban SJ , Profetto‐McGrath J
Published: July 2008

Abstract:  In order to test interventions for increasing uptake of research findings into dental hygiene practice, we must first identify factors that influence research use. There has been little work on this topic in dental hygiene, but much in other disciplines that can provide exemplars of how others have approached the study of this phenomenon.

Objectives:  A pilot study was conducted to determine if protocols used to study research utilization (RU) behaviours and critical thinking dispositions (CTD) in nursing could also be applied to dental hygiene.

Methods:  A cross‐sectional survey design was used with a random sample of 640 practicing dental hygienists in Alberta, Canada. Three questionnaires were included: one to capture measures of RU including direct, indirect and symbolic RU; the California Critical Thinking Dispositions Inventory (CCTDI) and a demographics questionnaire.

Results:  Mean responses for the three types of RU were highest for indirect at 3.52 (SD 0.720), followed by direct at 3.13 (SD 0.903) and symbolic 2.86 (SD 0.959). The majority (74.8%) scored between 280 and 350 on the CCTDI (maximum 420). Cronbach’s alpha reliability for the RU measures and four of the seven sub‐scales were over .7, indicating internal consistency reliability.

Conclusions:  The instruments proved reliable for this population, but other challenges, including a low response rate, were identified during the process of using the RU questionnaire in the context of dental hygiene practice. Pilot testing identified the need for improvements to the presentation of scales to reduce cognitive load and improve the response rate.
Dental beliefs, patients’ specific attitudes towards dentists and dental hygienists: a comparative study
Authors: Öhrn K , Hakeberg M , Abrahamsson KH
Published: July 2008

Abstract:  Interpersonal relationships are important for communication, oral health education and patients’ satisfaction with dental care. To assess patients’ attitudes towards dental caregivers, a Swedish version of the revised Dental Belief Survey (DBS‐R) and a comparable and partly new instrument the Dental Hygienist Belief Survey (DHBS) have been evaluated. The aim of the present study was to investigate if patients’ attitudes towards dental hygienists (DH) and dentists (D) differ with regard to the separate items in DBS‐R and DHBS. The study was a comparative cross‐sectional study with 364 patients (students, general patients and patients with periodontal disease). All patients completed the DBS‐R and DHBS surveys. The overall pattern in the results showed that participants in general had a less negative attitude towards DH when compared with that towards D. This was most pronounced among students and least pronounced among patients with periodontal disease. No statistically significant difference could be found in items with regard to feelings of shame and guilt in dental care situations, indicating that these items were rated on a more negative level also for DH. The conclusion is that participants had a less negative attitude towards DH with the exception of situations which may give rise to feelings of shame and guilt, an important finding for future dental hygiene care.
The Bass technique using a specially designed toothbrush
Authors: Battaglia A
Published: July 2008

Abstract:  Background:  Reducing the plaque index (PI) is still the main objective in the prevention of gingivitis and periodontitis.

Aim:  This experiment evaluated the efficiency of a new manual toothbrush shape from two perspectives: allowing the maximum exploitation of the bristle surface in all directions of the dental arches and simplifying the Bass technique handling and movements in domestic oral care.

Patients and method:  The distinct shape was obtained by distancing the bristle surface from the surface of the toothbrush handle in the direction of the bristles, maintaining the two surfaces on parallel planes. This modification facilitates brushing with the Bass technique, since rotation of the new toothbrush handle on its axis allows the bristle surface to cover a greater area. Sixteen patients between the ages of 23 and 49 years with at least 28 dental elements were divided randomly into two groups. On the first day, they underwent professional plaque removal and were provided with pairs of toothbrushes to test. They were evaluated 30 days later using the Full Mouth Plaque Score determined by two dental hygienists who were unaware of the instructions given concerning the method, quadrants and toothbrushes used for the experiment.

Results:  The results showed that the modifications to the manual toothbrushes produced greater PI control compared with the traditionally shaped toothbrushes.

Conclusion:  Although oral hygiene testing at home usually provides subjective information, in this experiment, the data provided a positive, objective result.
Dental hygiene regulation: a global perspective
Authors: Johnson PM
Published: July 2008

Abstract: Occupational regulation of health personnel is important to professional associations and their members, the public that relies on their services and the regulatory agencies responsible for their conduct. There is increasing interest in ensuring that dental hygiene regulation fosters the continuing evolution of the profession and its contribution to oral health. The keynote address for the 2007 Regulatory Forum on Dental Hygiene, this paper discusses the rationale for and issues pertaining to occupational regulation, outlines the evolvement of dental hygiene and identifies regulatory options for the profession. Professional regulation exists to ensure public safety, health and welfare. However, negative political‐economic side effects coupled with environmental pressures have resulted in increased scrutiny for health professionals. One such profession is dental hygiene. Its evolution has been dramatic, in particular over the past few decades, as illustrated by its rapidly increasing numbers and broader distribution globally, gradual shift to the baccalaureate as the entry‐level educational requirement and increase in postgraduate programs and expanding scope of practice and increased professional autonomy. Regulatory changes have been more gradual. Regulation is mandatory for the vast majority of dental hygienists. Of the options available, the practice act – the most rigorous type, is predominant. Globally, regulation tends to be administered directly by the government (n = 9 countries) more so than indirectly through a dental board (n = 4) or self‐regulation (n = 3). Whether regulated directly or indirectly, dental hygienists increasingly are seeking a greater role in shaping their professional future. Self‐regulation, its responsibilities, misperceptions and challenges, is examined as an option.
The effect of the Vector® scaler system on human teeth: a systematic review
Authors: Slot DE , Koster TJG , Paraskevas S , Van der Weijden GA
Published: July 2008

Abstract:  Aim:  To review the available literature, considering the effect of instrumentation with the Vector® ultrasonic scaler on human teeth in vitro and in vivo compared to conventional ultrasonic instruments and/or hand instrumentation. The assessed effects are calculus removal, time of instrumentation, root surface aspects, cell attachment, patients’ perception, bleeding upon probing, pocket depth, clinical attachment loss and microbiological effects.

Materials and methods:  MEDLINE–PubMed and the Cochrane Central register of controlled trials (CENTRAL) were searched up through January 2008 to identify appropriate studies.

Results:  Independent screening of the titles and abstracts of 270 MEDLINE–PubMed and 15 Cochrane papers resulted in 15 suitable publications. The studies differed in design and outcome, so this review summarizes the outcomes in a descriptive manner. Comparisons are presented against conventional ultrasonic system and scaling and root planing.

Conclusion:  The Vector® ultrasonic scaler provided comparable clinical and microbiological periodontal healing results as scaling and root planing and conventional ultrasonic system in moderately deep pockets. The Vector® ultrasonic scaler may be used as a gentle root debridement device for supportive periodontal therapy, as an alternative to other conventional ultrasonic system. The operator should however consider the extra time needed for instrumentation.
Early Bone Tissue Responses to Turned and Oxidized Implants in the Rabbit Tibia
Authors: Burgos Patricia Miranda , Rasmusson Lars , Meirelles Luiz , Sennerby Lars
Published: July 2008

Background: Previous studies have shown the formation of more bone contacts with a moderately rough and porous titanium surface, created by anodic oxidation, as compared with nonmodified turned titanium control surfaces. The mechanisms leading to a stronger bone response to oxidized titanium are not well understood.

Purpose: The aim of the study was to describe the early events of bone integration of titanium implants with oxidized and turned surfaces.

Materials and Methods: Nine adult New Zealand White rabbits and 18 implants were used in the study. One oxidized and one turned threaded titanium implants, which had been placed in the right tibial metaphysis, were analyzed in the present study. The implants were retrieved after 7, 14, and 28 days for light microscopic examination and histomorphometric measurements in ground sections.

Results: Integration of oxidized implants was seen to occur as direct bone formation on the surface, while the integration of turned implants was a result of bone ingrowth from preexisting bone and bone marrow. For oxidized implants, an almost acellular, darkly stained layer was seen after 7 to 14 days, which later became populated with osteoblasts. The presence of osteoid seams indicated appositional bone growth from the substrate toward the surrounding tissues. The bone contact values were higher for oxidized implants, and the bone area values were higher for turned implants.

Conclusions: The present study confirms the idea that implant surface modification alters the bone tissue response to titanium. The early bone formation following surgery occurs directly on the moderately rough oxidized surface, while turned titanium surfaces are integrated by the ingrowth of bone from the adjacent bone marrow and preexisting bone tissues.
Immunology, Microbiology, and Virology Following Placement of NobelPerfect™ Scalloped Dental Implants: Analysis of a Case Series
Authors: Nowzari Hessam , Yi Klaus , Chee Winston , Rich Sandra K.
Published: July 2008

Background: Cytokine–microbiology–virology monitoring after implant placement may help to develop profiles of variables that can help to explain interaction between the immune system and alveolar bone. Descriptive information at the molecular and cellular levels after implant placement is important in the emerging field of osteoimmunology and may help to formulate hypotheses and intervention strategies in periodontology and implantology.

Purpose: The purpose of this study was to determine the presence or absence of selected cytokines in association with periodontopathogens and human cytomegalovirus (HCMV) after placement of dental implants.

Materials and Methods: Charts of seven consecutive patients with 19 NobelPerfect™ (Nobel Biocare, Yorba Linda, CA, USA) implants were reviewed for crevicular fluid sample outcomes. Anaerobic culture determined periodontopathogens 2 to 5 days, 3 and 6 months postimplant insertion. At 3, 6, and 12 months, real‐time reverse transcriptase–polymerase chain reaction (RT–PCR) was performed to detect active HCMV, interleukin‐1beta (IL‐1β), tumor necrosis factor‐alpha (TNF‐α), and interferon‐gamma (INF‐γ).

Results: Four of five, and six of seven patients harbored no periodontopathogens at 3‐ or 6‐month intervals, respectively. In spite of absence of a bacterial challenge, IL‐1β and TNF‐α activity was significant. INF‐γ was not detected, and HCMV was present at one time interval only.

Conclusions: TNF‐α is produced mainly in the early stages of acute inflammation, and high levels of this cytokine at 3 and 6 months postimplant placement may be related to a repetitive acute‐phase inflammatory response. Lack of INF‐γ and a high cytokine presence without significant corresponding periopathogens or viruses raise a concern that inflammation and, thus, inflammatory bone destruction, is possible outside of these variables. Inflammation and bone loss around this same group of scalloped implants, reported by our previous study, may have been initiated by local factors, such as particular implant design features.
Esthetic Templates for Complex Restorative Cases: Rationale and Management
Authors: KOIS DEAN E. , SCHMIDT KYLE K. , RAIGRODSKI ARIEL J.
Published: July 2008

Complex restorative cases require difficult clinical decisions regarding the final esthetic outcome in which the operator must visualize the definitive restorative position of the teeth. These critical decisions need to be made before treatment is rendered. Communicating these decisions to the patient and the treatment team are crucial prior to achieving clinical success. The esthetic template is the conduit for providing excellent communication. The selection of the appropriate esthetic template is based on four sequential decisions: (1) dentofacial analysis, (2) blueprint development, (3) matrix management, and (4) template application. When utilizing an esthetic template, the clinician must know where the teeth should be placed based on a dentofacial analysis. The dentofacial analysis must then be communicated to the laboratory, and then a blueprint is developed from the diagnostic casts. A matrix is then fabricated from the blueprint and then related back to the existing dentition. The esthetic template is an invaluable communicator that can be utilized in office, with the patient at home, or even within the multidisciplinary treatment team. Clearly, the effective use of esthetic templates demonstrates a reversible way to visualize difficult esthetic decisions before any irreversible procedures are completed. Esthetic templates are a physical means of communication that provide the patient, technician, and multidisciplinary team an instrument to predictably manage complex restorative cases. The purpose of this article is to present a rationale for esthetic template selection and management of several techniques for complex restorative cases.

CLINICAL SIGNIFICANCE

Complex restorative cases require difficult clinical decisions regarding the final esthetic outcome in which the operator must visualize the definitive restorative position of the teeth. The use of an esthetic template commensurate with a rationale for selection enables the operator, patient, and entire interdisciplinary team to visualize the final esthetic outcome.
Abusive Supervision and Contextual Performance: The Mediating Role of Emotional Exhaustion and the Moderating Role of Work Unit Structure
Authors: Aryee Samuel , Sun Li-Yun , Chen Zhen Xiong George , Debrah Yaw A.
Published: July 2008

This study examined the processes linking abusive supervision to employee contextual performance by focusing on the mediating influence of emotional exhaustion and the moderating influence of work unit structure. Data were obtained from 285 subordinate–supervisor dyads from three manufacturing companies in north-eastern China. The results revealed that: (i) emotional exhaustion mediated the relationships between abusive supervision and the contextual performance dimensions of interpersonal facilitation and job dedication; and (ii) work unit structure moderated these relationships such that the relationships were stronger in mechanistic than in organic work unit structures.
Government-Oriented Corporate Public Relation Strategies in Transitional China
Authors: He Yuanqiong , Tian Zhilong
Published: July 2008

This study proposes an initial and a revised model of government-oriented public relation (PR) strategies based on the results of two content analyses of website news regarding the PR activities of 76 firms in general and six well-known firms in China in more depth. With the perspective of resource dependence theory, this model reveals that firms in China employ six types of formal PR strategies, including visitation, philanthropy, participation, publicity, party involvement and political propaganda, to manage their dependence on government for resources. Further, the implementation of such strategies involves a four-step process: organizing PR activities with economic, social and political significance; obtaining the involvement and recognition of the government; building firms' resource, moral and cultural legitimacy in the government's eyes; and interacting with the government on the issues of firms' dependence to influence government policies relative to firms. We also explore the differences that exist among firms with different ownership structures in the use of these PR strategies, the level of government involved and the issues pursued.