bluuebunny/crossref_metadata_2025 huggingface dataset:
Genomic imprinting: the influence of differential methylation in the two sexes
Authors: Biliya Shweta , Bulla Lee A
Published: May 2010

Genomic imprinting is an epigenetic form of gene regulation that entails differential sex-specific methylation of the alleles of a gene. Such methylation distinguishes male and female genomes and is inherited in a parent-of-origin-specific manner. Sex-specific imprints are established in the germline during gametogenesis and remain intact throughout embryonic and postnatal development. Reprogramming of methylation patterns in gametes is essential to sex-specific inheritance of imprinted genes and assures exclusive harboring of female- and male-specific imprinted patterns in maternal and paternal gametes, respectively. The consequences of genomic imprinting are manifested by its loss, which can lead to a variety of disorders, the most prominent ones being Prader–Willi and Angelman syndromes. Although a great deal of research has been carried out to examine various imprinting mechanisms, little is known about the establishment and regulation of imprinted genes. In the present paper, we describe several epigenetic mechanisms that have relevance in imprinting and that may have impact on embryonic development, fetal growth and animal cloning.
Induced pluripotent stem cells: what lies beyond the paradigm shift
Authors: Cox Jesse L , Rizzino Angie
Published: May 2010

The discovery that somatic cells can be reprogrammed to become induced pluripotent stem (iPS) cells has ushered in a new and exciting era in regenerative medicine. Since the seminal discovery of somatic cell reprogramming by Takahashi and Yamanaka in 2006, there has been remarkable progress in the characterization of iPS cells and the protocols used to generate them. The new information generated during the past year alone has vastly expanded our understanding of these cells. Accordingly, this review provides a basic overview of the different strategies used to generate iPS cells and focuses on recent developments in the field of iPS cells. In the final section, we discuss three broad, unanswered questions related to somatic cell reprogramming, which are just starting to be addressed.
Suppressive effects of genistein and daidzein on pituitary–thyroid axis in orchidectomized middle-aged rats
Authors: Šošić-Jurjević Branka , Filipović Branko , Ajdžanović Vladimir , Savin Svetlana , Nestorović Nataša , Milošević Verica , Sekulić Milka
Published: May 2010

High intake of soybean phytoestrogens, isoflavones genistein (G) and daidzein (D), has been associated with health benefits. However, isoflavones were reported to affect adversely thyroid function in the presence of other goitrogenic factors. As the thyroid gland becomes functionally impaired with age, we examined whether supplementary doses of G or D would affect morphology and function of pituitary–thyroid axis in middle-aged male rats. Sixteen-month-old orchidectomized Wistar rats were treated with 10 mg/kg of either G or D, while the control sham-operated and orchidectomized group received just the vehicle for three weeks. The animals were fed soy-free diet with increased iodine content, and killed 24 h after the last treatment. Their pituitaries and thyroids were excised and prepared for further immunohistochemical and morphometric investigation. The concentrations of thyroid-stimulating hormone (TSH), total T4and T3, in the serum were determined. In both isoflavone-treated groups, pituitary TSH-immunopositive cells had increased cellular volume and relative volume density ( P < 0.05), as well as increased serum TSH levels ( P < 0.05) in comparison to the controls; their thyroid tissue was characterized by increased volume of thyroglobulin-immunopositive epithelium ( P < 0.05), epithelial height and index of activation rate ( P < 0.05), while the volume of luminal colloid, and total serum T4and T3levels decreased ( P < 0.05) in comparison to the controls. In conclusion, this study provides the first direct evidence that both G and D can induce microfollicular changes in the thyroid tissue and reduce the level of thyroid hormones in Orx middle-aged male rats, a model of andropause. This reduction consequently led to a feedback stimulation of pituitary TSH cells. The detected stimulatory effect was higher in the daidzein-treated rats.
The challenge of hair cell regeneration
Authors: Groves Andrew K
Published: May 2010

Sensory hair cells of the inner ear are responsible for translating auditory or vestibular stimuli into electrical energy that can be perceived by the nervous system. Although hair cells are exquisitely mechanically sensitive, they can be easily damaged by excessive stimulation by ototoxic drugs and by the effects of aging. In mammals, auditory hair cells are never replaced, such that cumulative damage to the ear causes progressive and permanent deafness. In contrast, non-mammalian vertebrates are capable of replacing lost hair cells, which has led to efforts to understand the molecular and cellular basis of regenerative responses in different vertebrate species. In this review, we describe recent progress in understanding the limits to hair cell regeneration in mammals and discuss the obstacles that currently exist for therapeutic approaches to hair cell replacement.
Fluorescence monitoring of a photosensitizer and prediction of the therapeutic effect of photodynamic therapy for port wine stains
Authors: Wang Ying , Gu Ying , Liao Xiaohua , Chen Rong , Ding Huiying
Published: May 2010

In this study, a fluorescence method was established to obtain the local concentration of a photosensitizer (PS) based on the realtime fluorescence measurement of skin with port wine stain (PWS) during photodynamic therapy (PDT). This algorithm corrected for the distortions of PS fluorescence spectra imposed by the absorption of melanin and hemoglobin in skin and other factors, which yields a semi-quantitative measurement of PS concentration. Based on this information, a therapeutic effect correlation index (TECI) was proposed as the area under the PS concentration–time curve during PDT. The correlation between TECI and PDT treatment outcome was analyzed from 31 PWS patients. The measured PS fluorescence spectra showed that under the same PS dose, there were clear variations in the concentrations of the PS during PDT. Statistical analysis showed that TECI has a positive correlation with PDT outcome. Patients with a higher TECI value had a better treatment outcome. These results suggest that fluorescence spectroscopy can be used in situ to monitor skin PS concentration during PDT and to provide a valuable diagnostic tool to predict PDT outcome.
Model-derived assessment of cerebrovascular resistance and cerebral blood flow following traumatic brain injury
Authors: Daley Michael L , Narayanan Nithya , Leffler Charles W
Published: May 2010

The published guidelines point out the need for the development of methods that individualize patient cerebral perfusion management and minimize secondary ischemic complications associated with traumatic brain injury. A laboratory method has been developed to determine model-derived assessments of cerebrovascular resistance (mCVR) and cerebral blood flow (mCBF) from cerebrovascular pressure transmission, and the dynamic relationship between arterial blood pressure (ABP) and intracranial pressure (ICP). The aim of this two-fold study is to (1) evaluate relative changes in the model-derived parameters of mCVR and mCBF with the corresponding changes in the pial arteriolar vascular parameters of pial arteriolar resistance (PAR) and relative pial arteriolar blood flow (rPABF); and (2) examine the efficacy of the proposed modeling methodology for continuous assessment of the state of cerebrovascular regulation by evaluating relative changes in the model-derived parameters of CBF and cerebrovascular resistance in relation to changes of cerebral perfusion pressure prior to and following fluid percussion brain injury. Changes of ABP, ICP, PAR, relative arteriolar blood flow (rPABF) and the corresponding model-derived parameters of mCBF and mCVR induced by acute hypertensive challenge were evaluated before and following fluid percussion injury in piglets equipped with cranial windows. Before fluid percussion, hypertensive challenge resulted in a significant increase of PAR and mCVR, whereas both rPABF and mCBF remained constant. Following fluid percussion, hypertensive challenge resulted in a significant decrease of PAR and mCVR and consistent with impaired cerebrovascular regulation. Hypertensive challenge significantly increased both rPABF and mCBF, which approximately doubled with increased CPP with correlation values of r = 0.96 ( P < 0.01) and r = 0.97 ( P ≤ 0.01), respectively. The assessment of model-derived cerebrovascular resistance and CBF with changes of CPP provides a means to monitor continuously the state of cerebrovascular regulation.
No association between alleles of the bradykinin receptor-B2 gene and acute mountain sickness
Authors: Wang Pei , Koehle Michael S , Rupert Jim L
Published: May 2010

The pathophysiological mechanism(s) of the development of acute mountain sickness (AMS) is still unclear. Although the chance of developing AMS and the severity of the condition are influenced by ascent rate and altitude attained, previous history is a reliable predictor of subsequent affliction, and some individuals and families are clearly predisposed, suggesting a genetic component to susceptibility. As the vasodilator bradykinin may be involved in acclimatization to altitude, we hypothesized that variants in genes encoding components of this pathway might play a role in AMS susceptibility. We tested this by looking for associations between two functional polymorphisms (the in/del polymorphism +9/−9 [rs5810761] and the single-nucleotide polymorphism C − 58T [rs1799722]) of BDKRB2 (the gene encoding the bradykinin receptor B2) and susceptibility to AMS in an altitude-exposed Nepalese population. Lowland attendees ( n = 233) at a religious festival at 4380 m in the Nepalese Himalaya were recruited and assessed for AMS by clinical evaluation and Lake Louise score (LLS). Those with a clinical diagnosis of AMS and an LLS ≥3 were designated AMS+ ( n = 100) and those without a diagnosis of AMS and with an LLS <3 were categorized as AMS− ( n = 117). DNA was prepared from buccal cells, genotyped for the two polymorphisms and allele frequencies compared between the two cohorts. No association was found between alleles at either polymorphism and susceptibility to AMS ( P > 0.50), although C − 58T heterozygotes were significantly more common ( P < 0.001, χ2 = 49.6) in the subjects than would be predicted if the population was in Hardy–Weinberg equilibrium. The results of our association study do not support the hypothesis that variants in BDKRB2 influence altitude tolerance in a lowland Nepalese population; however, the deviation from Hardy–Weinberg equilibrium observed for the C − 58T polymorphism could be explained by self-selection for altitude tolerance in the festival attendees.
Effects of epigallocatechin-3-gallate on behavioral impairments induced by psychological stress in rats
Authors: Chen Wei-Qiang , Zhao Xiao-Ling , Wang Dong-Lan , Li Shu-Tian , Hou Yue , Hong Yan , Cheng Yi-Yong
Published: May 2010

This study was conducted to explore the effects of epigallocatechin-3-gallate (EGCG) on cognitive performances in psychological stress rats. An animal model of psychological stress was developed by restraint stress for three weeks. Male Wistar rats were randomly assigned to four groups as follows: normal control group, stress control group and two stress groups with green tea polyphenols (GTPs) and EGCG modulation, respectively. The changes of behavioral performances of rats were examined by the open-field test and step-through test. Results showed that behavioral performances of stress control group were changed abnormally, and they were improved in GTPs and EGCG modulation groups. In addition, plasma levels of cortisol, dopamine, norepinephrine, 5-hydroxytryptamine, interleukin-6 and interleukin-2 were detected. Stress control group had increased contents of cortisol, interleukin-6 and interleukin-2, and meanwhile had declined levels of 5-hydroxytryptamine and catecholamines. These changes in GTPs and EGCG modulation groups were similar to that of the normal control group. The expressions of metallothioneins in the hippocampus were detected by reverse transcription polymerase chain reaction. In contrast with the normal control group, their expressions in all the three stress groups were enhanced clearly. The results suggested that GTPs and EGCG modulation could improve the cognitive impairments induced by psychological stress. The related mechanisms may be involved with the changes of catecholamines, 5-hydroxytryptamine, cytokines and expressions of metallothioneins.
Characterization of porcine pregnane X receptor, farnesoid X receptor and their splice variants
Authors: Gray Matthew A , Pollock Callie B , Schook Lawrence B , Squires E James
Published: May 2010

The pregnane X receptor (PXR; NR1I2) and the farnesoid X receptor (FXR; NR1H4) regulate the expression of many major metabolic enzymes. With the pig being used as a model for humans in metabolic and toxicological studies and also an important food animal, we characterized the transactivation profile of the porcine orthologs of these receptors, pgPXR and pgFXR. We compared the transactivation profiles of these receptors and their splice variants to their human orthologs using mostly endogenous ligands. Five alternatively spliced variants were identified for pgFXR as part of this study, while five alternatively spliced variants of pgPXR had been previously described. Insertions and deletions within these splice variants generated truncated proteins or proteins with altered tertiary structures, resulting in altered transactivation. Realtime polymerase chain reaction analyses showed that the pgPXR variants were present in liver cDNA samples from 3.33% to 7.92% of the total pgPXR, while the pgFXR variants were present from 1.92% to 9.26% of the total pgFXR. pgFXR was fairly evenly expressed in seven different tissues. In a luciferase reporter assay, wild-type pgPXR (pgPXR-WT) and human PXR (hPXR) responded to 12 common ligands, with similar levels of activation occurring for six of these. Wild-type pgFXR (pgFXR-WT) significantly responded to three ligands, two of which also activated hFXR. 3-Methylindole (skatole) was identified as a novel inverse agonist for pgPXR-WT and pgFXR-WT as well as porcine constitutive androstane receptor. None of the pgPXR splice variants (SVs) were active in the luciferase reporter assay on their own; pgFXR-SV1 was activated by chenodeoxycholic acid to a similar degree as pgFXR-WT. When co-transfected with their corresponding wild-type proteins, pgPXR-SV1 and pgFXR-SV1 significantly increased receptor transactivation. In conclusion, pgPXR-WT and pgFXR-WT both responded to ligands that activated their human orthologs, and some of the alternatively spliced variants significantly altered pgPXR and pgFXR transactivation at in vivo expression levels.
Human embryonic stem cell-derived cardiomyocytes: demonstration of a portion of cardiac cells with fairly mature electrical phenotype
Authors: Pekkanen-Mattila Mari , Chapman Hugh , Kerkelä Erja , Suuronen Riitta , Skottman Heli , Koivisto Ari-Pekka , Aalto-Setälä Katriina
Published: May 2010

Cardiomyocytes (CMs) derived from human embryonic stem cells (hESC) provide a promising tool for the pharmaceutical industry. In this study the electrical properties and maturation of hESC-CM derived using two differentiation methods were compared and the suitability of hESC-CMs as a cell model for the assessment of drug-induced repolarization delay was evaluated. CMs were differentiated either in END-2 co-culture or by spontaneous differentiation. Action potentials (APs) were recorded from cells in spontaneously beating areas using the whole-cell patch-clamp technique. The hESC-CMs exhibited predominantly a ventricular-like phenotype with heterogeneous properties. Heterogeneity was indicative of the spectrum of hESC-CM maturation from embryonic-like with AP upstroke velocities <30 V/s and maximum diastolic potential (MDP) of close to −60 mV to more mature with values >150 V/s and −80 mV, respectively. The mean MDP was −70 mV and a significant difference was observed between the two differentiation methods (−66 versus −75 mV, P < 0.001). The age of the CMs did not correlate with phenotype maturation. The addition of the hERG blocker E-4031 and the sodium channel modulator veratridine significantly prolonged the AP duration. Furthermore, proarrhythmic indices were induced. In conclusion, the main observation was the heterogeneity in electrical properties of the hESC-CMs and this was observed with both differentiation methods. One-third of the hESC-CMs exhibited fairly mature electrophysiological properties, suggesting that mature CMs could be obtained from hESCs. However, improved differentiation methods are needed to produce homogeneous mature human CMs for pharmaceutical and toxicological applications.
Potent inhibition of peroxynitrite-induced DNA strand breakage and hydroxyl radical formation by dimethyl sulfoxide at very low concentrations
Authors: Jia Zhenquan , Zhu Hong , Li Yunbo , Misra Hara P
Published: May 2010

Dimethyl sulfoxide (DMSO) is frequently used as a solvent for many water-insoluble drugs in biological studies at concentrations often up to 1%. However, little is known about its effects on oxidatively generated DNA damage at very low concentrations (0.005–0.5%). This study was undertaken to investigate the effects of DMSO on peroxynitrite-induced DNA strand breaks, a critical event leading to peroxynitrite-elicited cytotoxicity. Incubation of φX-174 plasmid DNA, with 3-morpholinosydnonimine (SIN-1), a peroxynitrite generator, led to the formation of DNA strand breaks in a concentration- and time-dependent manner. The presence of DMSO at concentrations of 0.005–0.5% was found to significantly inhibit SIN-1-induced DNA strand breaks in a concentration-dependent manner. However, DMSO at the above concentrations showed no affect on SIN-1-mediated oxygen consumption, indicating that DMSO did not affect the auto-oxidation of SIN-1 to form peroxynitrite. It is observed that incubation of the plasmid DNA with authentic peroxynitrite resulted in significant formation of DNA strand breaks, which could also be dramatically inhibited by the presence of DMSO at 0.005–0.5%. Electron paramagnetic resonance spectroscopy, using 5,5-dimethylpyrroline- N-oxide (DMPO) as a spin trap demonstrated the formation of DMPO-hydroxyl radical adduct from the SIN-1 and authentic peroxynitrite. DMSO at the concentrations ranging from 0.01% to 0.5% significantly inhibited the adduct signal. Taken together, these studies demonstrate, for the first time, that DMSO at extremely low concentrations (0.005–0.5%) can potently inhibit peroxynitrite-mediated DNA strand breakage and hydroxyl radical formation. The results of this study suggest that, where DMSO is applied as a solvent, caution should be observed when evaluating the actions of drugs in experiments involving DNA damage.
An empirical approach to estimating the effect of e-health on medical expenditure
Authors: Akematsu Yuji , Tsuji Masatsugu
Published: May 2010

We studied the e-health system used in Nishi-aizu Town in Fukushima Prefecture in Japan. The system allows elderly people at home to transmit vital signs data to the Town's health centre, where nurses provide advice based on the data. Our hypothesis was that the e-health system in Nishi-aizu Town reduced the need to visit clinics. We attempted to prove this by a regression analysis, in which days for treatment were compared between users and non-users of e-health. The results showed that days for treatment of e-health users were shorter than those of non-users by 1.6 days per year. Thus the total reduction in expenditure as a result of fewer hospital visits (emergency and elective) was about 16,000 yen per year. In a previous study, we proved that in Nishi-aizu Town the medical expenditure of e-health users was smaller than those of non-users by 15,688 yen. The results of the present study therefore coincide with those of the previous one and show that the reduction of medical expenditure is principally caused by the reduction of days for treatment.
An international, case-based, distance-learning collaboration between the UK and Somaliland using a real-time clinical education website
Authors: Finlayson Alexander ET , Baraco Abdirazak , Cronin Nathalie , Johnson Oliver , Little Simon , Nuur Abdirahman , Tanasie Dragos , Leather Andy
Published: May 2010

We established a medical education website to deliver real-time, clinical case-based education to sites in Somaliland from the UK. The website was based on a web 2.0 social networking concept in order to recreate, as nearly as possible, the clinical bedside teaching experience. A survey showed that medical students in Somaliland had sufficient computer access to exploit the website. Teaching began in December 2008 and the teaching programme has developed into a regular weekly teaching session involving up to seven different student groups in Somaliland at different locations. As well as north-south teaching, the website has been employed to support a study module in London. Small groups of UK-based medical students have been partnered with intern tutors in Somaliland. Forty UK students have taken part in this teaching, which is now in its second year. Feedback from those involved has demonstrated that a collaboration in which both north–south and south–north teaching occurs can strengthen partnerships in which both parties contribute and benefit.
Automated weight monitoring in chronic heart failure: the excluded majority
Authors: Johnston Glenis , Weatherburn Gwyn
Published: May 2010

We interviewed nurses and patients with heart failure who were participating in a research trial of home telemonitoring in which weight data were monitored automatically by a call centre. A total of 35 interviews were conducted and the transcripts were analysed thematically. The results indicated that nurses disagreed about the role of weight monitoring and the practicalities of telemonitoring in their daily practice, indicating that the process was idiosyncratic to each user. The lack of personal feedback and nursing contact discouraged patients from weight monitoring, suggesting that a feedback mechanism may have to be adapted to suit patients. There were other factors which created barriers to acceptance by patients and staff. Home telemonitoring for heart failure cannot be evaluated effectively using the standard approach commonly employed. New studies are required.
A pilot trial of tele-ophthalmology services in north Wales
Authors: Kulshrestha Manoj , Lewis Delyth , Williams Chris , Axford Alan
Published: May 2010

We identified the need for a tele-ophthalmology service at the Tywyn hospital in Wales. During a two-year period, 22 emergency patients were managed by telemedicine, thereby reducing the need for ambulance transfer. We expect that there will be increased use of tele-ophthalmology in north Wales as the technology improves and the equipment becomes easier to use.
Use of digital images in the assessment and treatment of pressure ulcers in patients with spinal injuries in community settings
Authors: Sarhan Firas , Weatherburn Gwyn , Graham Allison , Thiyagarajan Chinnaya
Published: May 2010

We conducted a retrospective review of the digital images in the clinical records of 50 patients with pressure ulcers. Ten nurses independently assessed one image from each patient. There was a total of 414 responses from the nurses about the stage and location of the ulcers (83% response rate). The average agreement about the stage and location of the ulcers was 85%. The overall agreement declined as the stage of the ulcer increased. The average agreement regarding the wound descriptors was: necrosis 85%, granulation tissue 81%, ischaemia 83%, cellulitis /infection 69%, erythema 68%. Almost all nurses felt the need to change the current management of the wound (460 responses, or 92%). The nurses judged that most digital images were of good quality (17%) or very good quality (79%). The present study suggests that a high percentage of assessments for patients currently travelling to specialist clinics could be performed in the community using digital images and telemedicine.
Environmental aspects of health care in the Grampian NHS region and the place of telehealth
Authors: Wootton Richard , Tait Alex , Croft Amanda
Published: May 2010

Detailed information about the composition of the carbon footprint of the NHS in the Grampian health region, and in Scotland generally, is not available at present. Based on the limited information available, our best guess is that travel emissions in Grampian are substantial, perhaps 49,000 tonnes CO2 per year. This is equivalent to 233 million km of car travel per year. A well-established telemedicine network in the Grampian region, which saves over 2000 patient journeys a year from community hospitals, avoids about 260,000 km travel per year, or about 59 tonnes CO2 per year. Therefore using telehealth as it has been used historically (primarily to facilitate hospital-to-hospital interactions) seems unlikely to have a major environmental impact – although of course there may be other good reasons for persevering with conventional telehealth. On the other hand, telehealth might be useful in reducing staff travel and to a lesser extent, visitor travel. It looks particularly promising for reducing outpatient travel, where substantial carbon savings might be made by reconfiguring the way that certain services are provided.
Optimization, refinement and reduction of murine in vivo experiments to assess therapeutic approaches for haemophilia A
Authors: Baumgartner B , Jaki T , Wolfsegger M J , Eder B , Schiviz A , Schwarz H P , Muchitsch E M
Published: May 2010

The tail cut bleeding model (CUT) is routinely used in factor VIII-deficient mice to assess pharmacodynamic effects of therapeutic strategies for haemophilia A. Results from this model are highly variable, many modifications to the model are reported and at times the animals’ wellbeing may be compromised by recording survival as an endpoint. We therefore investigated if the ferric chloride carotid occlusion model (COM) used for thrombosis research can be applied to enhance data quality and animal welfare in haemophilia A research. Relative dose effects and relative dose variations were calculated for the CUT and COM. The requisite sample sizes were estimated and the importance of survival rates to assess rebleeds during recovery was evaluated by correlating initial blood loss to mortality. Relative dose effects increased with higher doses in both models. The COM was more sensitive at lower doses than the CUT, had up to 82% less variation across doses and clearly showed superior accuracy. Only 5% of the sample size required for the CUT would be needed to establish non-inferiority between a specific therapeutic dose in haemophilia A mice and healthy wild-type animals. A strong statistically significant correlation was found between initial blood loss and mortality within 24 h. Our findings clearly suggest that the COM is a valid tool for assessing haemophilia A treatment in vivo. The highly reproducible data means that significantly fewer animals are required and a more humane endpoint can be used by directly assessing clot stability instead of survival rate.
Statement from the Editor Regarding “New Perspectives on Customer ‘Death’ Using a Generalization of the Pareto/NBD Model”
Authors: Shugan Steven M.
Published: May 2010

In the original version of the paper “New Perspectives on Customer ‘Death’ Using a Generalization of the Pareto/NBD Model” by Kinshuk Jerath, Peter S. Fader, and Bruce G. S. Hardie (Marketing Science, Articles in Advance, May 27, 2010, DOI: 10.1287/mksc.1100.0568), some issues were brought to the attention of the journal by the authors after online publication in Articles in Advance. The accepting editor-in-chief, Steven M. Shugan, has chosen to retract the original published paper, allowing the authors the opportunity to resubmit a new paper that fully resolves those issues to the satisfaction of the authors and the journal.
Pricing, Frills, and Customer Ratings
Authors: Kuksov Dmitri , Xie Ying
Published: May 2010

This paper explores whether and how a firm should adapt its strategy in view of consumer use of prior customer ratings. Specifically, we consider optimal pricing and whether the firm should offer an unexpected frill to early customers to enhance their product experiences. We show that if price history is unobserved by consumers, a forward-looking firm should always modify its strategy from single-period optimal one, but it may be optimal to do so by lowering price, by lowering price and offering frills, or by raising price and offering frills, depending on the market growth rate. Specifically, the last strategy becomes optimal when market growth rate is high enough. The results are similar when the price history is observed by consumers, except that no deviation from single-period profit maximization choices is optimal when market growth is low enough. We also analyze whether the firm should prefer that the price information be stated in or left out of consumer reviews. In addition, in considering the effects of consumer heterogeneity, we conclude that the optimal firm's effort to affect ratings is higher when the idiosyncratic part of consumer uncertainty is larger.
The Effects of Online User Reviews on Movie Box Office Performance: Accounting for Sequential Rollout and Aggregation Across Local Markets
Authors: Chintagunta Pradeep K. , Gopinath Shyam , Venkataraman Sriram
Published: May 2010

Our objective in this paper is to measure the impact (valence, volume, and variance) of national online user reviews on designated market area (DMA)-level local geographic box office performance of movies. We account for three complications with analyses that use national-level aggregate box office data: (i) aggregation across heterogeneous markets (spatial aggregation), (ii) serial correlation as a result of sequential release of movies (endogenous rollout), and (iii) serial correlation as a result of other unobserved components that could affect inferences regarding the impact of user reviews. We use daily box office ticket sales data for 148 movies released in the United States during a 16-month period (out of the 874 movies released) along with user review data from the Yahoo! Movies website. The analysis also controls for other possible box office drivers. Our identification strategy rests on our ability to identify plausible instruments for user ratings by exploiting the sequential release of movies across markets—because user reviews can only come from markets where the movie has previously been released, exogenous variables from previous markets would be appropriate instruments in subsequent markets.

In contrast with previous studies that have found that the main driver of box office performance is the volume of reviews, we find that it is the valence that seems to matter and not the volume. Furthermore, ignoring the endogenous rollout decision does not seem to have a big impact on the results from our DMA-level analysis. When we carry out our analysis with aggregated national data, we obtain the same results as those from previous studies, i.e., that volume matters but not the valence. Using various market-level controls in the national data model, we attempt to identify the source of this difference.

By conducting our empirical analysis at the DMA level and accounting for prerelease advertising, we can classify DMAs based on their responsiveness to firm-initiated marketing effort (advertising) and consumer-generated marketing (online word of mouth). A unique feature of our study is that it allows marketing managers to assess a DMA's responsiveness along these two dimensions. The substantive insights can help studios and distributors evaluate their future product rollout strategies. Although our empirical analysis is conducted using motion picture industry data, our approach to addressing the endogeneity of reviews is generalizable to other industry settings where products are sequentially rolled out.
Current Issues Insurgical Education and Recommendations for Future Training
Authors: Fleming JC , Black IM
Published: May 2010

The surgical model of training in the UK has traditionally been viewed as a 'cumulative experience through mentorship and apprenticeship', drawing on a traditional apprenticeship, hospital-based education model such as that proposed by Halsted over a century ago. The European Working Time Directive (EWTD), Modernising Medical Careers (MMC) and the Intercollegiate Surgical Curriculum Programme (ISCP) have recently driven radical changes to this training model. These influences have resulted in significant changes in postgraduate specialty training, 'inducing educators to consider other possible changes in training that may better prepare trainees for the 21st-century world of practice'.
Getting Published in Medical Journals
Authors: Whitaker Matthew , Taylor Irving
Published: May 2010

Having a healthy list of publications on your CV has always been important for surgeons and trainees but the process of getting a paper published can be daunting, particularly if you have not done it before. This guide is intended to give some simple and useful advice on all aspects of the publishing process: what to write about, how to prepare a paper, where to submit and what to do next.
CCHDS and the Faculty of Dental Surgery
Authors: Altman Keith
Published: May 2010

The Central Committee for Hospital Dental Services (CCHDS) is an autonomous committee of the British Dental Association (BDA). It represents dental staff working in hospitals and dental public health on wider issues affecting NHS staff. An executive subcommittee supports the CCHDS.
Prestigious Medical Student Prize Awarded in the College
Authors: Jamjoom Aimun AB
Published: May 2010

The annual Professor Harold Ellis Medical Student Prize was held in the Royal College of Surgeons on 9 October 2009, with aspiring surgeons from around the country competing for the coveted award. This is the third year the prize has been held and its standing as one of the most sought-after medical student prizes is increasing by the year.
Impact of 'Two-Week Wait' Referrals for Suspected Bone or Soft Tissue Sarcoma
Authors: Barwick TW , Murray S , Gerrand C
Published: May 2010

The two-week wait (2ww) process has been in force since 2000 as part of the reform of cancer services in the NHS to ensure timely specialist review of patients with suspected cancer. In addition, more recently implemented waiting time standards dictate that for an urgent GP referral under the 2ww the time to diagnosis (decision to treat) should be less than 1 month (31-day rule) and from December 2005 the total time allowable from referral to treatment has been no more than two months (62-day rule). The Department of Health (DH) guidelines for referral under the 2ww have been unaltered since their inception (Figure 1).
Touchstone: an e-portfolio to support a modern dental workforce
Authors: O'Sullivan Julia
Published: May 2010

The Faculty of General Dental Practice (UK) is in the final stages of developing Touchstone, an innovative online portfolio. Touchstone will be rolled out to members through the FGDP(UK) divisions in the autumn before a national launch in January 2011. Touchstone's core functionality is to provide a central place for recording and evaluating all continuing professional development (CPD) activity and evidence. It has simple yet sophisticated ways to update, cross-reference and present this information.
Left Out: A Study to Determine Bimanual Dexterity in Practising Surgeons
Authors: Yadav R , O'Regan DJ
Published: May 2010

[T]hey be the best physicians, which being learned incline to the traditions of experience, or being empirics incline to the methods of learning.

Francis Bacon, The Advancement of Learning
Trends in Consultant Posts Advertised and SPRS Completing Training in General Surgery
Authors: Kirkby-Bott J , Nelson M
Published: May 2010

In the past ten years the NHS has seen radical changes to workforce strategies as well as the introduction of a new training system. Although national training numbers (NTNs), also known as Calman training, did not come with the guarantee of a consultant post, the latter was the only post for which Calman training was intended. In addition, it was the almost universal aim of Calman trainees to reach consultant status.
Decision time
Authors: Black John
Published: May 2010

By the time you read this the general election will be over and we will know (or perhaps not know) the political direction in which the country will be heading. It is encouraging that two of the three main parties should they be elected have committed themselves publicly to finding ways around the European Working Time Regulations (EWTR). This is in large part due to the campaign waged by the College on behalf of surgeons.
Influence of boundary conditions on photon diffusion through an interface between two turbid media with different refractive indices
Authors: Shendeleva Margarita L.
Published: May 2010

The photon migration in two semi-infinite highly scattering media with different refractive indices is studied in the diffusion approximation for two sets of boundary conditions at the interface. In commonly used boundary conditions, the ratio of the intensity (fluence rate) to the squared refractive index is assumed continuous across an interface and the normal component of flux is required to be continuous. However, a more rigorous approach shows that the boundary condition for the intensity may be different. As was shown by
Aronson [J. Opt. Soc. Am. A
12, 2532 (1995)]
, the ratio of the intensity to the squared refractive index undergoes a jump across an interface that is proportional to the diffuse flux. A diffusion model with an instantaneous point source that can be solved analytically for both sets of boundary conditions is considered. The analytical solutions are derived and compared with the results of Monte Carlo simulations that take into account the reflections and refractions at the interface according to Fresnel’s formulas. It is shown that the analytical solutions with the Aronson boundary condition for intensity match the Monte Carlo results better than the solutions with a continuous ratio of the intensity to the squared refractive index.
Mueller matrix interpolation in polarization optics
Authors: Devlaminck V.
Published: May 2010

The question of the physical significance of the Mueller matrix average is addressed by means of an analysis of interpolation processes. We draw a comparison between two interpolation processes. The first one is related to the classical Euclidean metrics and the second one is based on the log-Euclidean metrics. Both the associated interpolation procedures are depicted with their underlying physical models. Addressing the question of the physical meaning of the log-Euclidean process of interpolation is founded on a very similar approach to the layered-medium interpretation proposed by
Jones [J. Opt. Soc. Am.
38, 671 (1948)]
in the seventh paper of his series. Based on the analysis of their respective properties, we eventually show that the choice between both these interpolation processes may depend on what statistical situation is considered or what underlying physical model is assumed.
Measurement and modeling of 2D hexagonal resonant-grating filter performance
Authors: Fehrembach A.-L. , Gauthier-Lafaye O. , Yu K. ChanShin , Monmayrant A. , Bonnefont S. , Daran E. , Arguel P. , Lozes-Dupuy F. , Sentenac A.
Published: May 2010

We report the measurement of a polarization-independent guided-mode resonant filter with a Q factor of
∼2200
functioning near normal incidence in the near infrared
(850 nm)
. Besides this remarkable performance, we provide a detailed optical and structural characterization of the component, which points out the origins of the limitation of the experimental performance. We conclude that the defaults in question can be corrected by improving the lithography process, and we are confident that even greater performance will be obtained in future realizations.
Mesh-Free Solution of Two-Dimensional Edge Crack Problems under Thermo-Mechanical Load
Authors: Pant Mohit , Singh I. V. , Mishra B. K. , Bhasin Vivek , Sharma Kamal , Khan I. A.
Published: May 2010

In this work, a mesh-free approach known as element free Galerkin method (EFGM) has been used to obtain the solution of two-dimensional edge crack problems in linear elastic fracture mechanics subjected to thermo-mechanical loads. The diffraction criterion has been modified with multiple crack weight technique to characterize the presence of all cracks in the domain of the influence of a node. The effect of crack orientation has been studied for two edge cracks lying on the same face as well as on opposite faces under plane stress conditions. The values of mode-I and mode-II stress intensity factors have been evaluated by domain based interaction integral approach. The results obtained by EFGM are compared with those obtained by finite element method.
Phase Change and Mechanical Behaviors of TixCoCrFeNiCu1−yAly High Entropy Alloys
Authors: Zhang Y. , Chen G. L. , Gan C. L.
Published: May 2010

The alloying effects of the Al, Ti, Cu, and Co in a typical TixCoCrFeNiCu1−yAly high entropy alloy (HEA) were systematically studied. The phase change of the HEAs is closely related to the atomic packing efficiency of the phases. The high entropy of the alloy will largely lower the Gibbs free energy when the enthalpy of the alloys are not changed too much, and the high entropy phase can be an equilibrium stable one. The HEAs can have ultrahigh fracture strength at room temperature and high temperature, e.g., yield strength of 1400 MPa at 500°C.
Efflorescence: Evaluation of Published Test Methods for Brick and Efforts to Develop a Masonry Assembly Test Method
Authors: Chin Ian R. , Behie Bill
Published: May 2010

The test method determining the efflorescence potential of brick is found in ASTM C67-08, Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile. This test method is based upon the “wick tests” performed at the National Bureau of Standards in 1930 to determine the tendency for 684 brick to effloresce. Both Britain and Russia have also published efflorescence test methods for brick. From 1995 through 2006, Task Group C15.02.26 on Efflorescence, a subcommittee of ASTM C15.02 on Brick and Structural Clay Tile, evaluated the effectiveness of the ASTM C67-08 efflorescence test method. C15.02 is a subcommittee of committee C15 on Manufactured Masonry Units. The performance results for the ASTM, British, Russian and a modified ASTM C67-08 test on a standard brick were compared. This evaluation revealed that the ASTM C67-08 and the Russian efflorescence test methods were equally effective in predicting efflorescence potential of brick. The British test method was shown not to be effective in predicting efflorescence potential of brick. The efflorescence that developed on the types of brick rated as “effloresced” was more extensive and intense on the brick tested by the ASTM C67-08 method than the brick tested by the Russian method. In 1998, Task Group C15.05.15 on Efflorescence of Masonry Assemblies of ASTM subcommittee C15.05 on Masonry Assemblies prepared ASTM C1400-07, Standard Guide for Reduction of Efflorescence Potential in New Masonry Walls. C15.05 is a subcommittee of committee C15 on Manufactured Masonry Units. Subsequently, Task Group C15.05.15 began testing to obtain information to develop a test method to predict efflorescence potential in new masonry assemblies. The testing is ongoing. The various test methods evaluated to date include the following: (1) Open top plastic box with brick test specimen inserted in each face and filling of the box with a slurry of the test mortar ingredients; (2) open top brick masonry box constructed with the brick and mortar test specimens and filling of the box with water; (3) brick masonry wallettes constructed with the brick and mortar test specimens and placed in 1-in.-deep water and exposed to moving air from a fan; and (4) masonry cubes made from ground-up brick test specimens and mortar test specimens and placed in 1-in.-deep water and exposed to moving air from a fan. This paper presents the results of the evaluation of the ASTM C67-08 efflorescence test method by Task Group C15.02.26 and of the efforts made to date by Task Group C15.05.15 to develop an efflorescence test method for masonry assemblages.
Sediment Volume Tests for Expansive Soil Identification and Classification
Authors: Prakash K. , Sridharan A.
Published: May 2010

Equilibrium sediment volume tests are conducted on field soils to classify them based on their degree of expansivity and/or to predict the liquid limit of soils. The present technical paper examines different equilibrium sediment volume tests, critically evaluating each of them. It discusses the settling behavior of fine-grained soils during the soil sediment formation to evolve a rationale for conducting the latest version of equilibrium sediment volume test. Probable limitations of equilibrium sediment volume test and the possible solution to overcome the same have also been indicated.
Modeling the Effects of Temperature and Loading Rate on Fatigue Property of Asphalt Binder
Authors: Wen Haifang , Shen Shihui , Ma Zhanpeng , Wang Jingan
Published: May 2010

Fatigue cracking is one of three major distresses for asphalt pavement. Asphalt binder is a very important component of asphaltic mixture. The fatigue performance of asphalt binder also greatly affects that of asphaltic mixture. Asphalt binder’s fatigue characteristics are affected by external conditions, such as temperature and loading rate. It is warranted to study the effects of these external conditions on fatigue of asphalt binder and take them into account. New fatigue tests and properties have been proposed to characterize the fatigue behavior of asphalt binders, such as monotonic constant shear-rate tests. This study investigated the effects of temperature and shear rate on fatigue properties of asphalt binder. Two asphalt binders were tested with a range of temperature and shear rates. It was found that time-temperature superposition principle also applies to critical strain energy density and shear strength of asphalt binders. The values of shift factors for building the master curves of critical strain energy and shear strength are comparable.
DATEV-INTERACT - eine Businessapplikation für Microsoft Surface
Authors: Hanke Marion , Toussaint Claude
Published: May 2010

Wie kann man die Möglichkeiten eines interaktiven Multi-Touch-Tisches optimal nutzen? Mit dieser zentralen Frage setzt sich designaffairs in den verschiedensten Projekten auseinander. Für die DATEV eG entwickelte die Münchner Agentur eine Microsoft Surface Anwendung, die den Steuerberater beim Mandantengespräch unterstützt. Im Folgenden werden die Erkenntnisse aus der Konzeption und Realisierung dieser Anwendung beschrieben und diskutiert.
User Centered Product Innovation
Authors: Hofer Ron , Götzfried Stefanie
Published: May 2010

Mythen umgeben die meisten großen Erfindungen. Fast immer findet man darin den Heureka-Moment: Newton musste erst ein Apfel auf den Kopf fallen, damit er die Gravitationstheorie beschreiben konnte. Die Entwicklung erfolgreicher Innovationen gestaltet sich weitaus nüchterner. Was macht Sie aus, die Innovation, wenn es nicht die magische Idee ist? In diesem Beitrag wird User Centered Product Innovation als eine Möglichkeit vorgestellt, im Wettlauf der Innovationen, Konzepte zu identifizieren, die sich an die (zukünftigen) Bedürfnisse der (zukünftigen) Nutzergruppen richten. Die Darstellung des Methodenspektrums des noch jungen Feldes zeigt, welche kreativen Wege zur Sondierung neuer Innovationsfelder bereits beschritten werden, welche Unterschiede sich zum klassischen User Research im Usability Engineering ergeben und in welchen Bereichen noch Bedarf zur Weiterentwicklung dieses Ansatzes besteht.