bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Thoughts About What Might Have Been
Authors: Beck Sarah R. , Riggs Kevin J.
Published: January 2015

Recent research has changed how developmental psychologists understand counterfactual thinking or thoughts of what might have been. Evidence suggests that counterfactual thinking develops over an extended period into at least middle childhood, depends on domain‐general processes including executive function and language, and dissociates from counterfactual emotions such as regret. In this article, we review the developmental evidence that forms a critical but often‐overlooked complement to the cognitive, social, and neuroscience literatures. We also highlight topics for further research, including spontaneous counterfactual thinking and counterfactual thinking in clinical settings.
Adult phenotype of Russell‐Silver syndrome: A molecular support for Barker‐Brenner's theory
Authors: Takenouchi Toshiki , Awazu Midori , Eggermann Thomas , Kosaki Kenjiro
Published: January 2015

Developmental Origins of Health and Disease theory stems from large‐scale epidemiologic observation. The presumed mechanism for this hypothesis includes epigenetic changes; however, it remains to be elucidated if individuals with intrauterine growth retardation and epigenetic changes confirmed at the molecular level are indeed susceptible to adult‐onset disease. Here we document three individuals with Russell‐Silver syndrome, a prototypic condition caused by hypomethylation of the differently methylated imprinting center region 1 (ICR1) between the IGF2 and H19 loci on chromosome 11p15. At follow‐up, the three patients developed adult‐onset diseases such as obesity, hypertension, and diabetes mellitus in their early 20s. The presence of molecularly confirmed epigenetic changes in these patients provides a biological basis for Barker‐Brenner's theory at an individual level.
“(MA)LINGERING ON THE DISABLED LIST”
Authors: Krautmann Anthony C. , Solow John L.
Published: January 2015

In this article, we examine two offsetting incentives that may affect a baseball player's willingness to play with injuries. We allow for the usual disincentive effects associated with long‐term contracts, while also incorporating the importance of the incentives associated with contract renewal. Our results are consistent with the previous work that showed those likely to retire at the end of their current contracts have an increased incentive to shirk. For those who expect to re‐sign a subsequent contract, however, we find that players tend to step up their effort as they approach the final year of their contract. (JEL L83)
Utility of Intracardiac Echocardiography for Catheter Ablation of Complex Cardiac Arrhythmias in a Medium‐Volume Training Center
Authors: Filgueiras‐Rama David , de Torres‐Alba Fernando , Castrejón‐Castrejón Sergio , Estrada Alejandro , Figueroa Jorge , Salvador‐Montañés Óscar , López Teresa , Moreno‐Yanguela Mar , López Sendón José L. , Merino José L.
Published: January 2015

Aims and Objectives

New electrophysiology tools like intracardiac echocardiography (ICE) might help to minimize and early detect complications during cardiac ablation procedures. The aim of the study was to assess the utility and vascular safety of ICE during catheter ablation of complex cardiac arrhythmias in a medium‐volume training center.

Methods

Prospective, observational study consisted of consecutive patients who underwent catheter‐based ablation of complex cardiac arrhythmias. All procedures were performed using three‐dimensional electro‐anatomical mapping and routine cannulation of right and left femoral veins. The ICE probe was initially positioned at the mid‐level of the right atrium and properly moved to monitor different steps of the procedure and identify complications. All procedure‐related vascular complications were registered.

Results

One hundred two patients (age 61.4 ± 13.1 years, 69 male) underwent 110 ablation procedures. Pulmonary vein isolation was the most common ablation substrate (55.4%). Ventricular tachycardia (17.2%) and left atrial flutter procedures (16.4%) were also common. The use of ICE enabled us to early initiate anticoagulation and to optimize the transseptal puncture. It also provided the capability to early detect life‐threatening complications such as tamponade (3.6%), along with important information during the procedure such as exact catheter location, lesion formation, and stability during radiofrequency delivery. Such benefits were not associated with a higher number of vascular complications.

Conclusion

The use of ICE during catheter‐based ablation of complex cardiac substrates provides technical features that may decrease complications and increase accuracy while applying radiofrequency, especially in training centers where fellows start to perform complex procedures.
Mating success at high temperature in highland‐ and lowland‐derived populations as well as in heat knock‐down selected Drosophila buzzatii
Authors: Sambucetti Pablo , Norry Fabian M.
Published: January 2015

Thermal‐stress selection can affect multiple fitness components including mating success. Reproductive success is one of the most inclusive measures of overall fitness, and mating success is a major component of reproduction. However, almost no attention has been spent to test how mating success can be affected by thermal‐stress selection. In this study, we examine the mating success in the cactophilic Drosophila buzzatii Patterson & Wheeler (Diptera: Drosophilidae) derived from two natural populations that nearly represent the ends of an altitudinal cline for heat knock‐down resistance. Furthermore, we extended the analysis using laboratory lines artificially selected for high and low heat knock‐down resistance. Mating success at high temperature was found to be higher in the lowland than the highland population after a heat pre‐treatment. Moreover, individuals selected for heat knock‐down resistance showed higher mating success at high temperature than did individuals selected for low knock‐down resistance. These results indicate that adaptation to thermal stress can confer an advantage on fitness‐related traits including mating success and highlight the benefits of earlier heat exposure as an adaptive plastic response affecting mating success under stress of higher temperature.
Capital in the Twenty‐First Century by Thomas Piketty
Authors: Jardat Rémi
Published: January 2015

The success of Piketty's book can be explained by several factors. A first factor is the contrast between his defense of a reasonably egalitarian and meritocratic vision of society, shared by European and American readers, and his convincing argument that that meritocracy system is under serious threat. The radically shocking nature of his arguments is coupled with the vast amount of empirical proof he has put forward to support them. Second, a remarkable clarity of expression underlies a simple theoretical approach to interpreting a panorama of data (allowing him to deliver a careful and well‐documented discussion of statistics, without sacrificing readability, something that is often sadly lacking in the cryptic mathematical computations that economists are typically known for). And, to illustrate his points, the author presents a variety of insightful literary references taken from nineteenth century romantic novels. Last but not least, his ambitious scope is noteworthy, dealing with cross‐country distributions of wealth and income, across broad swaths of time, through a cross‐disciplinary lens of economics, history and sociology.
Recruitment, distribution boundary and habitat temperature of an arcto‐boreal gadoid in a climatically changing environment: a case study on Northeast Arctic haddock (Melanogrammus aeglefinus)
Authors: Landa Camilla S. , Ottersen Geir , Sundby Svein , Dingsør Gjert E. , Stiansen Jan E.
Published: January 2015

Climate change is expected to have major effects on the distribution and abundance of fish. In spite of extensive research on the topic in high‐latitude marine ecosystems, the mechanistic understanding of how temperature impacts recruitment and distribution of arcto‐boreal fish stocks remains elusive. Exemplified by an arcto‐boreal gadoid in the Barents Sea, the Northeast Arctic (NEA) haddock (Melanogrammus aeglefinus), we investigate the effect of ecosystem temperature (here temperature from a fixed reference section) on abundance and distribution boundaries between 1981 and 2008. During this time interval there has been a trend of increasing temperature in the ecosystem. We compare the ecosystem temperature with the species habitat temperature ofNEAhaddock (i.e., ambient temperature of the population) – two temperature approaches representing the indirect and direct environmental impacts on fish, respectively. In addition to the temperature effects, density‐dependent effects on distribution boundaries are considered. The study is based on swept area density estimates and spatial temperature data collected annually in winter surveys. We found a positive relationship between ecosystem temperature and abundance, a connection related to both direct and indirect mechanisms with short‐term and long‐term pathways. Distribution boundaries are, on a year‐to‐year basis, more related to abundance than ecosystem temperature. The long‐term trends, however, indicate a north‐eastward shift in distribution boundaries, probably indirectly related to the coinciding ecosystem temperature increase. In spite of the gradual increase in ecosystem temperature, the abundance of 4‐ to 7‐ year oldNEAhaddock expanded into colder waters. Thus, our results show how different the two temperature approaches may be.
Aggression is associated with aerobic glycolysis in the honey bee brain1
Authors: Chandrasekaran S. , Rittschof C. C. , Djukovic D. , Gu H. , Raftery D. , Price N. D. , Robinson G. E.
Published: January 2015

Aerobic glycolysis involves increased glycolysis and decreased oxidative catabolism of glucose even in the presence of an ample oxygen supply. Aerobic glycolysis, a common metabolic pattern in cancer cells, was recently discovered in both the healthy and diseased human brain, but its functional significance is not understood. This metabolic pattern in the brain is surprising because it results in decreased efficiency of adenosine triphosphate (ATP) production in a tissue with high energetic demands. We report that highly aggressive honey bees (Apis mellifera) show a brain transcriptomic and metabolic state consistent with aerobic glycolysis, i.e. increased glycolysis in combination with decreased oxidative phosphorylation. Furthermore, exposure to alarm pheromone, which provokes aggression, causes a metabolic shift to aerobic glycolysis in the bee brain. We hypothesize that this metabolic state, which is associated with altered neurotransmitter levels, increased glycolytically derived ATP and a reduced cellular redox state, may lead to increased neuronal excitability and oxidative stress in the brain. Our analysis provides evidence for a robust, distinct and persistent brain metabolic response to aggression‐inducing social cues. This finding for the first time associates aerobic glycolysis with naturally occurring behavioral plasticity, which has important implications for understanding both healthy and diseased brain function.
The Diagnostic Validity of Citric Acid‐Free, High Dose 13C‐Urea Breath Test After Helicobacter pylori Eradication in Korea
Authors: Kwon Yong Hwan , Kim Nayoung , Lee Ju Yup , Choi Yoon Jin , Yoon Kichul , Hwang Jae Jin , Lee Hyun Joo , Lee AeRa , Jeong Yeon Sang , Oh Sooyeon , Yoon Hyuk , Shin Cheol Min , Park Young Soo , Lee Dong Ho
Published: January 2015

Background

The 13C‐urea breath test (13C‐UBT) is a noninvasive method for diagnosing Helicobacter pylori (H. pylori) infection. The aims of this study were to evaluate the diagnostic validity of the 13C‐UBT cutoff value and to identify influencing clinical factors responsible for aberrant results.

Methods

13C‐UBT (UBiTkit; Otsuka Pharmaceutical, cutoff value: 2.5‰) results in the range 2.0‰ to 10.0‰ after H. pylori eradication therapy were compared with the results of endoscopic biopsy results of the antrum and body. Factors considered to affect test results adversely were analyzed.

Results

Among patients with a positive 13C‐UBT result (2.5‰ to 10.0‰, n = 223) or a negative 13C‐UBT result (2.0‰ to < 2.5‰, n = 66) after H. pylori eradication, 73 patients (34.0%) were false positive, and one (1.5%) was false negative as determined by endoscopic biopsy. The sensitivity, specificity, false‐positive rate, and false‐negative rate for a cutoff value of 2.5‰ were 99.3%, 47.1%, 52.9%, and 0.7%, respectively, and positive and negative predictive values of the 13C‐UBT were 67.3% and 98.5%, respectively. Multivariate analysis showed that a history of two or more previous H. pylori eradication therapies (OR = 2.455, 95%CI = 1.299–4.641) and moderate to severe gastric intestinal metaplasia (OR = 3.359, 95%CI = 1.572–7.178) were associated with a false‐positive 13C‐UBT result.

Conclusion

The 13C‐UBT cutoff value currently used has poor specificity for confirming H. pylori status after eradication, and this lack of specificity is exacerbated in patients that have undergone multiple prior eradication therapies and in patients with moderate to severe gastric intestinal metaplasia. In addition, the citric‐free 13C‐UBT would increase a false‐positive 13C‐UBT result.
Metallothionein gene expression is altered in oral cancer and may predict metastasis and patient outcomes
Authors: Brazão‐Silva Marco T , Rodrigues Maria Fernandes S , Eisenberg Ana Lúcia A , Dias Fernando L , de Castro Luciana M , Nunes Fábio D , Faria Paulo R , Cardoso Sérgio V , Loyola Adriano M , de Sousa Suzana C O M
Published: January 2015

Aims

Metallothioneins (MTs) are proteins associated with the carcinogenesis and prognosis of various tumours. Previous studies have shown their potential as biomarkers in oral squamous cell carcinoma (OSCC). Aiming to understand more clearly the function of MTs in OSCC we evaluated, for the first time, the gene expression profile of MTs in this neoplasm.

Materials and results

Tissue samples from 35 cases of tongue and/or floor of mouth OSCC, paired with their corresponding non‐neoplastic oral mucosa (NNOM), were retrieved (2007–09). All tissues were analysed for the following genes using TaqMan® reverse transcription–quantitative polymerase chain reaction (RT–qPCR) assays: MT1A, MT1B, MT1E, MT1F, MT1G, MT1H, MT1X, MT2A, MT3 and MT4. The expression of MT1B and MT1H was seldom detected in both OSCC and NNOM. A significant loss of MT1A, MT1X, MT3 and MT4 expression and gain of MT1F expression was observed in OSCC, compared to NNOM. Cases with MT1G down‐regulation exhibited the worst prognoses. The up‐regulation of MT1X was restricted to non‐metastatic cases, whereas up‐regulation of MT3 was related to cases with lymph node metastasis.

Conclusions

Metallothionein mRNA expression is altered significantly in oral squamous cell carcinomas. The expression of MT1G, MT1X and MT3 may aid in the prognostic discrimination of OSCC cases.
Three‐Dimensional Modeling of Glass Lens Molding
Authors: Sarhadi Ali , Hattel Jesper H. , Hansen Hans N.
Published: January 2015

The required accuracy for the final dimensions of the molded lenses in wafer‐based precision glass molding as well as the need for elimination of costly experimental trial and error calls for numerical simulations. This study deals with 3D thermo‐mechanical modeling of the wafer‐based precision glass lens molding process. First, a comprehensive 3D thermo‐mechanical model of glass is implemented into aFORTRANuser subroutine (UMAT) in theFEprogramABAQUS, and the developedFEmodel is validated with both a well‐known sandwich seal test and experimental results of precision molding of several glass rings. Afterward, 3D thermo‐mechanical modeling of the wafer‐based glass lens manufacturing is performed to suggest a proper molding program (i.e., the proper set of process parameters including preset force‐time and temperature‐time histories) for molding a wafer to a desired dimension and quality. Moreover, the effect of some important process parameters such as cooling rate and pressing temperature on the final size and residual stress inside the wafer is evaluated. Finally, it is noted that the suggested molding program minimizes the costly empirical efforts and raises the process efficiency.
Safety evaluation of aflatoxin B1 in peanut oil after ultraviolet irradiation detoxification in a photodegradation reactor
Authors: Diao Enjie , Shen Xiangzhen , Zhang Zheng , Ji Ning , Ma Wenwen , Dong Haizhou
Published: January 2015

The high incidence of aflatoxin B1 (AFB1) in peanut oil has caused wide public concern in the world. Many studies have verified that ultraviolet (UV) irradiation can degrade AFB1 in foods. A new photodegradation reactor has been developed to study the photodegradation efficiency of AFB1 in peanut oil, and the safety of peanut oil was evaluated after UV irradiation detoxification based on the mutagenicity of Salmonella typhimurium tester strains and cytotoxicity of HepG2 cells. The results showed that AFB1 in peanut oil could be decomposed efficiently using the photodegradation reactor. AFB1 was decreased from 51.96 ± 4.24 to 7.23 ± 0.59 μg kg−1 in 10 min and reduced by 86.08% compared with that of the negative control. The residual AFB1 in peanut oil was far less than the limit level set by Chinese government (20 μg kg−1). The Ames test and cell viability assay revealed that 10 min of UV irradiation reduced significantly the toxicity of AFB1 in peanut oil. All the results suggest that the deleterious effects of AFB1 can be highly reduced by UV irradiation in the photodegradation reactor, and the reactor can be applied in a large scale in detoxification of AFB1 in peanut oil in the oil industry.
Earlier menarcheal age in Spanish girls is related with an increase in body mass index between pre‐pubertal school age and adolescence
Authors: Gavela‐Pérez T. , Garcés C. , Navarro‐Sánchez P. , López Villanueva L. , Soriano‐Guillén L.
Published: January 2015

Background

Higher body mass index (BMI) has been associated with earlier pubertal development.

Objective

The aim of this longitudinal study was to determine menarcheal age in a Spanish cohort and to assess its association with anthropometric variables at birth, childhood and adolescence. We also analyse whether the tracking of weight between different ages could affect the timing of menarche.

Methods

The sample population included 195 randomly selected 6–8‐year‐old girls who participated in the baseline of the Four Provinces Study and in the follow‐up of this study at 13–16 years old. Anthropometrical variables were measured and BMI and BMI z‐score were calculated. Information regarding birth weight and menarche was obtained by means of self‐report questionnaire.

Results

Correlation analysis showed a significant negative association of age at menarche with weight, BMI and BMI z‐score in the baseline and follow‐up groups but not with weight at birth. Fat mass at adolescence is related to a significantly earlier menarcheal age. When comparing weight categories, earliest menarcheal age is associated with an increase of BMI between 6–8‐year‐old and 13–16‐year‐old girls.

Conclusion

In our study, high weight in girls is associated with the earliest age at menarche. This becomes a major influence when weight gain occurs between pre‐pubertal school age and adolescence.
Analysis of a dynamic lot‐sizing problem with production capacity constraint
Authors: Zhang Zhicong , Yan Xiaohui , Li Shuai
Published: January 2015

We study a capacitated dynamic lot‐sizing problem with special cost structure involving setup cost, freight cost, production cost, and inventory holding cost. We investigate two cases of the problem categorized by whether the maximal production capacity in one period is an integral multiple of the capacity of a container and reveal the special structure of an optimal solution for each case. In the case where the maximal production capacity is an integral multiple of a container's capacity, the T‐period problem is solved using polynomial effort by a network algorithm. For the other case, the problem is transformed into a shortest path problem, and a network‐based algorithm combining dynamic programming is proposed to solve it in polynomial time. Numerical examples are presented to illustrate application of the algorithms to solve the two cases of the problem.
A study on the use of heuristics to solve a bilevel programming problem
Authors: Angelo Jaqueline S. , Barbosa Helio J. C.
Published: January 2015

The bilevel programming problem is characterized as an optimization problem that has another optimization problem in its constraints. The leader in the upper level and the follower in the lower level are hierarchically related where the leader's decisions affect both the follower's payoff function and allowable actions, and vice versa. One difficulty that arises in solving bilevel problems is that unless a solution is optimal for the lower level problem, it cannot be feasible for the overall problem. This suggests that approximate methods could not be used for solving the lower level problem, as they do not guarantee that the optimal solution is actually found. However, from the practical point of view near‐optimal solutions are often acceptable, especially when the lower level problem is too costly to be exactly solved thus rendering the use of exact methods impractical. In this paper, we study the impact of using an approximate method in the lower level problem, discussing how near‐optimal solutions on the lower level can affect the upper level objective function values. This study considers a bilevel production‐distribution planning problem that is solved by two intelligent heuristics hierarchically related: ant colony optimization for solving the upper level problem, and differential evolution method to solve the lower level problem.
Neuronal cells and neurotrophins in odontogenesis
Authors: Luukko Keijo
Published: January 2015

There is evidence from lower animals that in addition to oral ectoderm and cranial neural crest, tooth formation depends on neuronal cells. To analyze the possible neural influence on mammalian tooth formation, peripheral nerve fibers and neuronal cells were localized in the area of the developing rat first molar tooth germ. Moreover, to study whether factors needed for neuronal development might be involved in the regulation of tooth formation and innervation, expression of NGF‐related neurotrophic factors and their receptors were localized by in situ hybridization. The data suggest that although peripheral nerve fibers appear not to be required for odontogenesis, neuronal cells associated with the embryonic rat tooth may participate in the regulation of tooth formation. Localization of neurotrophins and their receptors suggests that besides their apparent roles in the regulation of tooth innervation, they may serve non‐neuronal, organogenetic functions during tooth formation. Moreover, it is possible that neuronal characteristics of the dental mesenchymal cells and the presence of neuronal cells in the tooth germs may explain the specific ability of neural crest‐derived, but no other mesenchymal, cells to contribute to mammalian tooth formation.
A novel approach for inhibiting growth factor signalling in murine tooth development: Inhibition of FGF's
Authors: Tucker A. S. , Markham H. J. , Green P. , Doherty P. , Sharpe P. T.
Published: January 2015

Growth factors belonging to the FGF and TGF‐β families, together with other secreted factors such as Sonic hedgehog, have been shown to be spatially and temporally regulated during tooth development. Providing evidence of the functions of these molecules has, however, proved difficult. We have developed a novel strategy for investigating the role of secreted molecules in tooth development using soluble forms of membrane bound receptors to sequester ligands. Chimeric fusion proteins of receptor extracellular domains were cloned into the eukaryotic expression vector pIG‐1 and transfected into COS cells. Fusion proteins secreted by the COS cells were purified using Protein A Sepharose. A soluble form of the FGF receptor FGF‐1IIIc, which preferentially binds FGF‐2 and FGF‐4, was produced using this technique and added to mouse mandible cultures. Addition of the soluble receptors to E13 cultures resulted in down‐regulation of Sonic hedgehog expression in molar enamel knots, consistent with inhibition of FGF‐4 signalling.
TGF‐β1 is essential for the homeostasis of the dentin‐pulp complex
Authors: D'Souza Rena N. , Cavender Adriana , Dickinson Douglas , Roberts Anita , Letterio John
Published: January 2015

Among the complex network of cytokines that influence odontoblast function during development and repair, TGF‐β1 is unique in its dual abilities to function as a potent immunosuppressant and as an inducer of extracellular matrix production. These properties underscore the importance of this molecule in maintaining the homeostasis of the dentin‐pulp complex after injury. The purpose of this paper is to describe new findings of our phenotypic analysis of dentition in mice in which the TGF‐β1 gene has been disrupted. The major phenotype of TGF‐β1 (−/−) offspring is one of diffuse immune system activation with progressive inflammation, wasting and death. Our studies of adult TGF‐β1 (−/−) dentition show widespread pulpal and periapical inflammation and necroses. In addition, the coronal surfaces of occluding molars show marked attrition. To determine whether the phenotypic changes in TGF‐β1 (−/−) dentition are directly linked to the loss of TGF‐β1 rather than the inflammatory process itself, we studied adult dentition in TGF‐β1 (−/−) mice backcrossed into immunodeficient backgrounds. Results of our histopathologic and radiographic analyses show that teeth of TGF‐β1 (−/−) immunodeficient mice retain vitality in pulpal and periapical regions but show excessive wear of occlusal surfaces.
Dentin phosphoprotein sequence motifs and molecular modeling: conformational adaptations to mineral crystals
Authors: Dahlin Stefan , Ångström Jonas , Linde Anders
Published: January 2015

Molecular modeling has been used to investigate structural features of oligopeptides derived from possible primary structure motifs in highly phosphorylated dentin phosphoprotein (PP‐H), the predominant non‐collagenous protein in dentin. It contains a large number of aspartate (Asp) and phosphoserine (Pse) residues, the latter proposedly crucial for the PP‐H function as a mineral nucleator. In this work, computer fitting and subsequent structural adaptation of model peptides, built exclusively from Asp and Pse, to the known crystal structures of hydroxyapatite (HAP) and octacalcium phosphate (OCP) were performed. The results show that, when considering conformational energies of fitted single strand oligopeptides, either crystal will serve. Within a narrow range, fitting to OCP was slightly favored, except for oligo(Pse‐Pse‐Asp‐Asp), which showed a slightly better fit to HAP. Energy differences between crystal‐adapted and non‐adapted freely minimized peptides showed that oligo(Pse‐Asp) docked to either HAP or OCP were the energetically most favored adaptations. Fitting of minimized triple anti‐parallel β‐strands of oligo(Pse‐Asp) or oligo(Pse‐Pse‐Asp), motifs found in published sequences of rat, mouse, and bovine PP‐H. revealed that a (001) crystal face of HAP, but most likely not OCP, may be formed by these β‐sheet models. The former motif is more advantageous in this respect.
Dentin‐specific proteins in MDPC‐23 cell line
Authors: Hanks Carl T. , Fang Danan , Sun Zhilin , Edwards Chris A. , Butler William. T.
Published: January 2015

Only four established odontoblast‐like cell lines have been reported in the literature (1–6). Of the four, only two synthesize dentin‐specific proteins. These studies report that the cell line MO6‐G3 synthesizes phosphophoryn (DPP), dentin sialoprotein (DSP) and dentin matrix protein‐1 (DMP‐1), while MDPC‐23 synthesizes DSP, but not DMP‐1. The objective of the present study was to determine whether polyclonal antibodies to rat DSP and DPP would label odontoblasts on microscopic sections of day‐19 fetal mouse incisor odontoblasts as well as cultured cells of the MDPC‐23 cell line. The spontaneously immortalized MDPC‐23 cell line was derived from fetal mouse molar papillae, made continuous by the 3T6 method and cloned by dilution. These cultures have been passaged 77 times after cloning, form multilayered nodules, and have high alkaline phosphatase activity. The data show positive reactivity in odontoblasts in 19‐d mouse fetal incisors as well as in cultures of MDPC‐23 cells by fluorescence and confocal microscopy. In addition, these cultures were characterized by phase microscopy and scanning and transmission electron microscopy. These findings suggest that MDPC‐23 cells are of the odontoblast lineage.
Demonstration of putative Ca‐binding domains in dentin matrix of rat incisors after daily injections of 1‐hydroxyethylidene‐1,1‐bisphosphonate (HEBP)
Authors: Takano Yoshiro , Sakai Hideo , Baba Otto , Sakamoto Yujiro , Terashima Tatsuo , Ohya Keiichi , Kurosaki Norimasa
Published: January 2015

In order to clarify the initial process of dentin mineralization, the inhibitory effect of 1‐hydroxyethylidene‐1,1‐bisphosphonate (HEBP) on dentin mineralization was investigated. Rats (100 g) were subcutaneously injected with HEBP (8 mg P/kg) for 7 or 14 d, and the incisors were processed for Ca histochemistry and/or electron microscopy. HEBP‐treated incisors demonstrated ladder‐like alternate rows of mineralized and non‐mineralized dentin at the apical end. GBHA revealed moderate Ca reactions in the non‐mineralized circumpulpal dentin matrix where electron microscopy revealed rich distribution of fine mesh‐like electron‐dense material. Non‐mineralized mantle dentin matrix was negative for Ca but contained numerous matrix vesicles (MVs) filled with crystalline and/or amorphous mineral deposits. Mineralization of circumpulpal dentin occurred independently of MV‐rich mantle dentin layer in affected specimens. Our data provide histochemical evidence of possible Ca‐binding property of the circumpulpal dentin matrix and its absence in the mantle dentin where MV‐mediated mineralization occurs. In the mantle dentin, HEBP does not interfere with crystal growth in MVs but inhibits its outgrowth after membrane rupture. It is proposed that circumpulpal dentin matrix has a potential to mineralize independently of MV‐mediated mineralization of mantle dentin, although MVs determine the initial site and timing of dentin mineralization.
Formation of reparative acellular extrinsic fiber cementum in relation to implant materials installed in rat periodontium
Authors: Beertsen Wouter , van den Bos Theo , Niehof Anneke , Everts Vincent
Published: January 2015

The aim of the present study was to determine the nature of the cells associated with the formation of reparative acellular extrinsic fiber cementum (AEFC). Calcifying collagen membranes, hydroxyapatite particles and/or non‐resorbable ePTFE membranes were implanted in lesions made in the periodontium of the rat mandibular incisor. The incisor was prevented from erupting further, and the animals were killed after 1–8 wk. In the first week, next to cells with a fibroblastic phenotype, epithelial cells (ECs) migrating out of the reduced enamel epithelium were among the cells colonizing the wounds. From 2 wk on, the ECs showed regressive changes and disappeared. Along mineralized implant surfaces, a basophilic layer enriched in osteopontin (but without detectable amelogenin) was deposited. After 3 wk (when ECs were no longer present) the healing tissue transformed into a well‐organized PDL‐like tissue, and AEFC started to develop. Along the non‐mineralizing ePTFE membranes, AEFC did not form except in regions where small calcified bodies were present. It is concluded that reparative AEFC layers are formed only along calcified surfaces. The cells associated with this reparative activity are periodontal ligament cells with a fibroblastic phenotype.
Evolution of patterns and processes in teeth and tooth‐related tissues in non‐mammalian vertebrates
Authors: Huysseune Ann , Sire Jean‐Yves
Published: January 2015

The evolutionary links that exist between odontodes and organs that are phylogenetically related to them (teeth and scales) suggest the use of comparative approaches to study these structures. Part one of this review briefly introduces current ideas on how the pattern of odontodes and odontode‐derived tissues has been established during evolution to yield the diversity of odontode‐related organs currently observed in nature in the cranial and postcranial skeleton. This introductory survey is used to highlight aspects of the developmental processes underlying the formation of some of these organs and the resemblance their development bears to odontogenesis. Part two provides a concise survey of the diversity of tooth structure in the different classes of extant vertebrates, in particular with reference to enamel/enameloid and dentine structure, and tooth attachment. Against this background, the current state of knowledge is reviewed with regard to developmental mechanisms involved in non‐mammalian odontogenesis. Common structure and similarities in development demonstrate that teeth and odontode derivatives should not be considered subjects of separate lines of research. On the contrary, results acquired in one of these fields are relevant to the other and may disclose model species that are relevant to studies on mammalian odontogenesis.
Activity of alkaline and acid phosphatases in dental epithelial cells and enameloid during odontogenesis in two teleost fish, Oreochromis niloticus and Tilapia buttikoferi
Authors: Sasagawa Ichiro
Published: January 2015

The dental epithelial cells and enameloid at the stages of enameloid matrix formation, mineralization and maturation in the teleosts Oreochromis niloticus and Tilapia buttikoferi were investigated by means of enzyme histochemistry in order to identify their functions associated with the structural modification. No marked enzyme activities were found in the inner dental epithelial cells in the stage of enameloid matrix formation, although the outer dental epithelial cells often exhibited moderate alkaline phosphatase (ALPase) activity. In the stages of enameloid mineralization and maturation, the inner dental epithelial cells, which possessed a ruffled border at the distal ends, showed intense ALPase activity at their lateral and proximal cell membranes. At the same time, many acid phosphatase (ACPase)‐positive vesicles and granules were localized at the distal cytoplasm of the inner dental epithelial cells. The outer dental epithelial cells, which contained well‐developed labyrinthine canalicular spaces, showed neither marked ALPase nor ACPase activity. It is postulated that the dental epithelial cells in these two teleosts are mainly involved in the removal of the organic matrix from the enameloid, and in material transport to the enameloid during the later half of odontogenesis.
Exigences des créanciers et des actionnaires en matière d’information dans les entreprises à capital ouvert par rapport aux entreprises à capital fermé observations européennes
Authors: PEEK ERIK , CUIJPERS RICK , BUIJNK WILLEM
Published: January 2015

Les auteurs se demandent si l’importance de l’information comptable dans l’établissement de contrats et la communication avec les actionnaires et les créanciers a une incidence sur la rapidité de publication de l’information sur les résultats (c’est‐à‐dire sur l’actualité de cette information), dans les états financiers à vocation générale diffusés dans le public. Pour opérationnaliser la relation entre les exigences relatives à l’actualité de l’information et l’importance de l’information comptable pour les actionnaires et les créanciers, les auteurs comparent l’actualité de l’information sur les résultats (l’asymétrie de cette information) dans les entreprises à capital ouvert par rapport aux entreprises à capital fermé. Ils attribuent les écarts dans l’actualité de l’information entre les entreprises à capital ouvert et les entreprises à capital fermé aux exigences des actionnaires, dans les pays où les institutions assurent une solide protection aux investisseurs. De façon analogue, ils attribuent ces écarts aux exigences des créanciers, dans les pays où les institutions assurent une solide protection aux créanciers. Leur analyse des entreprises à capital ouvert et à capital fermé dans 13 pays de l’Europe occidentale semble indiquer que les créanciers et les actionnaires ont des exigences différentes relativement à l’actualité de l’information. Les auteurs constatent notamment que l’écart entre les entreprises à capital ouvert et les entreprises à capital fermé en ce qui a trait à l’asymétrie de l’actualité de l’information n’est pas associéà la mesure dans laquelle un pays protège les investisseurs, mais qu’il affiche une relation positive avec la mesure dans laquelle un pays protège les créanciers. Les résultats de l’étude tendent également à démontrer que les actionnaires réclament la symétrie plutôt que l’asymétrie de l’actualité de l’information. Ces observations débouchent sur une conclusion importante : les états financiers à vocation générale sont sensibles aux exigences d’information des créanciers, ce qui contraste avec l’hypothèse selon laquelle ces créanciers — essentiellement privés — s’intéresseraient aux rapports à vocation spéciale.
Annoncer ou ne pas annoncer? Causes et conséquences de l’abandon des annonces de résultats trimestriels prévisionnels
Authors: HOUSTON JOEL F. , LEV BARUCH , TUCKER JENNIFER WU
Published: January 2015

Depuis quelques années, les annonces de résultats trimestriels prévisionnels font l’objet de sévères critiques, leurs détracteurs affirmant qu’elles incitent à la gestion à courte vue et à d’autres péchés. C’est pourquoi les institutions influentes enjoignent aux dirigeants de cesser la publication de résultats trimestriels prévisionnels. Les auteurs examinent empiriquement les causes de cet abandon de la publication de résultats trimestriels prévisionnels et constatent que la piètre performance opérationnelle — bénéfices à la baisse, résultats inférieurs aux prévisions des analystes et rentabilité prévue plus faible — est le principal motif pour lequel les entreprises abandonnent les annonces de résultats trimestriels prévisionnels. Dans les entreprises qui ont abandonné ces annonces, les auteurs n’observent pas de croissance appréciable de l’investissement à long terme après que les dirigeants se soient libérés de la myopie des investisseurs. Contrairement à l’affirmation selon laquelle les entreprises publieraient davantage d’autres informations à caractère prévisionnel en remplacement des annonces de résultats trimestriels et prévisionnels, les auteurs constatent que les entreprises se dérobent. Ils observent également une détérioration de l’environnement informationnel des entreprises qui cessent la publication de résultats trimestriels prévisionnels, détérioration qui se manifeste par un plus grand nombre d’erreurs dans les prévisions des analystes et une plus grande dispersion des prévisions et par une diminution de l’intérêt des analystes. Ces constatations révèlent, dans leur ensemble, que les entreprises qui abandonnent les annonces de résultats trimestriels prévisionnels sont principalement des entreprises en difficulté, et que la décision d’abandon n’est avantageuse ni pour les entreprises qui la prennent ni pour leurs investisseurs.
Quand les analystes ajustent‐ils leurs évaluations en fonction du biais des annonces de résultats prévisionnels ? Conséquences de la feuille de route des entreprises en ce qui a trait à la publication de résultats prévisionnels et enjeux motivant les analystes
Authors: TAN HUN‐TONG , LIBBY ROBERT , HUNTON JAMES E.
Published: January 2015

Les études précédentes indiquent que les analystes n’ajustent pas totalement leurs évaluations en fonction du biais général à la baisse des annonces de résultats prévisionnels faites par les directions d’entreprises. Les auteurs rapportent les résultats de deux expériences visant à déterminer comment la feuille de route des entreprises en ce qui a trait à la publication de résultats prévisionnels et les enjeux motivant les analystes expliquent de concert la mesure dans laquelle ces derniers ajustent leurs évaluations en fonction du biais des annonces de résultats prévisionnels. Ces résultats d’expérience semblent indiquer que les analystes pour qui l’enjeu est celui de l’exactitude ajustent leurs évaluations selon la feuille de route de la direction en ce qui a trait à la publication de résultats prévisionnels biaisés à la baisse lorsque le biais est relativement modeste (un cent), mais que les analystes pour qui l’enjeu est celui de leur relation avec la direction s’en abstiennent. Au surplus, la différence dans l’ajustement est plus importante lorsque la feuille de route de l’entreprise en matière de biais est irrégulière que lorsqu’elle est régulière. Aussi, lorsque le biais des annonces de résultats prévisionnels est plus important que moins (deux cents par rapport à un cent), les analystes pour qui l’enjeu est celui de la relation avec la direction procèdent à un ajustement partiel, paraissant ainsi rechercher un équilibre entre exactitude et volonté de plaire à la direction. Ces constatations ont des répercussions pour les investisseurs, les autorités de réglementation et l’interprétation des études précédentes.
Audits des Cinq Grands et fraude comptable
Authors: LENNOX CLIVE , PIZTTMAN JEFFREY A.
Published: January 2015

Les auteurs examinent le lien entre les audits des Cinq Grands et l’incidence des fraudes comptables présumées de sociétés ouvertes des États‐Unis entre 1981 et 2001. Selon bon nombre de commentateurs, les défaillances retentissantes de l’information financière qui ont menéà des réformes radicales de la gouvernance d’entreprise soulèvent de sérieux doutes quant à savoir si les grands cabinets d’expertise comptable continuent d’offrir des audits d’une qualité relativement élevée, en particulier depuis quelques années. Toutefois, dans des échantillons non appariés et appariés, les auteurs relèvent des données solides et robustes permettant de conclure que la publication d’information financière frauduleuse est moins probable en la présence d’un auditeur des Cinq Grands. Fait important, les tests des séries chronologiques laissent supposer qu’il existe un lien caractérisé entre les Cinq Grands et l’incidence plus faible de la fraude comptable, y compris dans les cinq dernières années de la période d’échantillonnage, au cours desquelles le nombre de fraudes a monté en flèche. De plus, les auteurs recueillent des preuves que ce lien est de nature causale et n’est pas un simple facteur endogène dans le choix de l’auditeur.
Indication de la performance de l’entreprise au moyen de la présentation des états financiers: une analyse faisant appel aux éléments exceptionnels
Authors: RIEDL EDWARD J. , SRINIVASAN SURAJ
Published: January 2015

Les auteurs se demandent si le fait pour les directions d’entreprises de présenter des éléments exceptionnels dans les états financiers reflète la performance économique ou révèle l’opportunisme. Ils comparent plus précisément les éléments exceptionnels présentés sous la forme d’un poste distinct de l’état des résultats (présentation en résultats) à ceux qui sont intégrés à un autre poste et présentés uniquement dans les notes complémentaires (présentation par voie de notes). L’étude est motivée par l’intérêt des normalisateurs pour l’information relative à la performance et la présentation des états financiers, ainsi que par les études antérieures relatives aux choix du mode de présentation par les directions d’entreprises, dans d’autres contextes. Les résultats empiriques révèlent que les éléments exceptionnels qui sont présentés en résultats sont moins persistants que ceux qui sont présentés par voie de notes. Ces observations demeurent les mêmes, peu importe les différentes spécifications adoptées. Dans l’ensemble, les constatations des auteurs confirment que les directions d’entreprises qui préfèrent la présentation en résultats à la présentation par voie de notes ont pour but d’aider les utilisateurs à repérer les éléments exceptionnels les plus susceptibles d’être différents des autres éléments des résultats, c’est‐à‐dire que leurs motifs sont plus informationnels qu’opportunistes.
Creditors’ and Shareholders’ Reporting Demands in Public Versus Private Firms: Evidence from Europe
Authors: PEEK ERIK , CUIJPERS RICK , BUIJINK WILLEM
Published: January 2015

In this study we investigate whether the importance of accounting information in contracting and communication with shareholders and creditors affects earnings timeliness in publicly disclosed general‐purpose financial statements. To operationalize the relationship between timeliness demands and the importance of accounting information to shareholders and creditors, we compare the (asymmetry in) earnings timeliness of public firms with that of private firms. We attribute public versus private firm differences in timeliness to shareholders’ demands when a country’s institutions provide strong investor protection. Similarly, we attribute these differences to creditors’ demands when the institutions provide strong creditor protection. Our analysis of public and private firms in 13 Western European countries suggests that creditors and shareholders have different timeliness demands. In particular, we find that the public versus private firm difference in asymmetric timeliness is not associated with a country’s degree of investor protection but positively associated with a country’s degree of creditor protection. The results further suggest that shareholders demand symmetric rather than asymmetric timeliness. An important implication of our study is that general‐purpose financial statements are responsive to creditors’ reporting demands, which contrasts with the idea that these — primarily private — creditors would use special‐purpose reports.
To Guide or Not to Guide? Causes and Consequences of Stopping Quarterly Earnings Guidance
Authors: HOUSTON JOEL F. , LEV BARUCH , TUCKER JENNIFER WU
Published: January 2015

In recent years, quarterly earnings guidance has been harshly criticized for inducing “managerial short‐termism” and other ills. Managers are, therefore, urged by influential institutions to cease guidance. We examine empirically the causes of such guidance cessation and find that poor operating performance — decreased earnings, missing analyst forecasts, and lower anticipated profitability — is the major reason firms stop quarterly guidance. After guidance cessation, we do not find an appreciable increase in long‐term investment once managers free themselves from investors’ myopia. Contrary to the claim that firms would provide more alternative, forward‐looking disclosures in lieu of the guidance, we find that such disclosures are curtailed. We also find a deterioration in the information environment of guidance stoppers in the form of increased analyst forecast errors and forecast dispersion and a decrease in analyst coverage. Taken together, our evidence indicates that guidance stoppers are primarily troubled firms and stopping guidance does not benefit either the stoppers or their investors.