bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reply to discussion of ‘Empirical vs natural weighting in random effects meta‐analysis’
Authors: Shuster Jonathan J. , Hatton Randy C. , Hendeles Leslie , Winterstein Almut G. 
Published: May 2010

AbstractThree discussion papers raise interesting points, but at the end of the day, we continue to recommend that past meta‐analyses which have influenced public policy or clinical paradigms be reanalyzed by unweighted methods. For all future meta‐analyses that employ either (a) fixed effects where concomitant treatment and/or eligibility are diverse or (b) classical random effects weighted methods, unweighted methods should serve as the primary analysis. Other analyses would be reasonable as secondary approaches. Two commentaries suggest that weights are only random to the extent of estimation errors in the between study and within study variance components. We shall demonstrate that even if these components are known, there is still considerable random variability in the weights. In fact, methods that try to weight the estimates inversely proportional to the variance have a number of undesirable properties, including bias, incorrect standard errors, inconsistency (including coverage of confidence intervals), and counter‐intuitive properties that the expectation of the estimator changes both with the number of studies sampled and with constant multiples of sample size across all studies. These adverse properties do not exist for the unweighted approach. From the numerical example of phenylephrine 10 mg, despite the arguments of Waksman, the proper conclusion is that the collection of studies does not constitute evidence‐based support for efficacy in terms of lowering nasal airway resistance. In the final section, we present two compelling examples where questionable inferences were made, with potential major public implications. Copyright © 2010 John Wiley & Sons, Ltd.
A two‐component nonlinear mixed effects model for longitudinal data, with application to gastric emptying studies
Authors: Kim Inyoung , Cohen Noah D. , Roussel Allen , Wang Naisyin 
Published: May 2010

AbstractGastric emptying studies are of great interest in human and veterinary medical research to evaluate effects of medications or diets for promoting gastrointestinal motility and to examine unintended side‐effects of new or existing medications, diets, or procedures. Summarizing gastric emptying data is important to allow easier comparison between treatments or groups of subjects and comparisons of results among studies. The standard method for assessing gastric emptying is by using scintigraphy and summarizing the nonlinear emptying of the radioisotope. A popular model for fitting gastric emptying data is the power exponential model. This model can only describes a globally decreasing pattern and thus has the limitation of poorly describing localized intragastric events that can occur during emptying. Hence, we develop a new model for gastric emptying studies to improve population and individual inferences using a mixture of nonlinear mixed effects models. One mixture component is based on a power exponential model which captures globally decreasing patterns. The other is based on a locally extended power exponential model which captures both local bumping and rapid decay. We refer to this mixture model as a two‐component nonlinear mixed effects model. The parameters in our model have clear graphical interpretations that provide a more accurate representation and summary of the curves of gastric emptying pattern. Two methods are developed to fit our proposed model: one is the mixture of an Expectation Maximization algorithm and a global two‐stage method and the other is the mixture of an Expectation Maximization algorithm and the Monte Carlo Expectation Maximization algorithm. We compare our methods using simulation, showing that the two approaches are comparable to one another. For estimating the variance and covariance matrix, the second approach appears approximately more efficient and is also numerically more stable in some cases. Our new model and approaches are applicable for assessing gastric emptying in human and veterinary medical research and in many other biomedical fields such as pharmacokinetics, toxicokinetics, and physiological research. An example of gastric emptying data from equine medicine is used to demonstrate the advantage of our approaches. Copyright © 2010 John Wiley & Sons, Ltd.
Are joint ventures positive sum games? The relative effects of cooperative and noncooperative behavior
Authors: Kumar M. V. Shyam 
Published: May 2010

AbstractAre joint ventures (JVs) characterized mainly by cooperative behavior or noncooperative behavior? In this research, we address this question by examining the interrelationship between the values created for two partners when they announce a JV. We argue that, on average, if cooperative behavior and common benefits are more influential than noncooperative behavior and private benefits, there will be a positive association between the values created for the two partners. Conversely, if private benefits and noncooperative behavior are more influential, there will be a negative association as partners derive value at the expense of each other rather than by creating new opportunities through the JV. Using a sample of 344 JVs we find evidence of a positive association between the values created for the two partners after controlling for various factors. This suggests that the stock market perceives JVs to be positive sum games rather than zero sum games, and that value creation in JVs is mainly attributable to synergies rather than appropriation of resources. Our analysis also reveals other conditions under which cooperative behavior and noncooperative behavior become dominant, such as the strength of the resources of the two partners, product market competition, and JV experience. Copyright © 2010 John Wiley & Sons, Ltd.
Testing management theories: critical realist philosophy and research methods
Authors: Miller Kent D. , Tsang Eric W. K. 
Published: May 2010

AbstractThis study identifies the practical and philosophical difficulties associated with testing strategic management and organization theories. Working from a critical realist perspective, we affirm the importance of falsification and verification efforts for progress in theory development. We advocate a four‐step approach for advancing theory testing that prioritizes identifying and testing for the presence and effects of hypothesized causal mechanisms, rather than solely focusing on correlational methods to jointly test the set of effects composing a theoretical system. Going beyond prior critical realist writings, we provide practical guidance for deploying established research methods to test management theories. Copyright © 2010 John Wiley & Sons, Ltd.
Cancer‐Cell‐Specific Induction of Apoptosis Using Mesoporous Silica Nanoparticles as Drug‐Delivery Vectors
Authors: Rosenholm Jessica M. , Peuhu Emilia , Bate‐Eya Laurel Tabe , Eriksson John E. , Sahlgren Cecilia , Lindén Mika 
Published: May 2010

AbstractTargeted delivery of the chemotherapeutic agent methotrexate (MTX) to cancer cells using poly(ethyleneimine)‐functionalized mesoporous silica particles as drug‐delivery vectors is reported. Due to its high affinity for folate receptors, the expression of which is elevated in cancer cells, MTX serves as both a targeting ligand and a cytotoxic agent. Enhanced cancer‐cell apoptosis (programmed cell death) relative to free MTX is thus observed at particle concentrations where nonspecific MTX‐induced apoptosis is not observed in the nontargeted healthy cell line, while corresponding amounts of free drug affect both cell lines equally. The particles remain compartmentalized in endo‐/lysosomes during the time of observation (up to 72 h), while the drug is released from the particle only upon cell entry, thereby inducing selective apoptosis in the target cells. As MTX is mainly attached to the particle surface, an additional advantage is that the presented carrier design allows for adsorption (loading) of additional drugs into the pore network for therapies based on a combination of drugs.
Large luteinized follicular cyst of pregnancy
Authors: Mavromatidis G. , Sotiriadis A. , Dinas K. , Mamopoulos A. , Rousso D. 
Published: May 2010

AbstractA large (165 × 235 × 250 mm) solitary, unilocular cyst with a thin, smooth wall and homogeneous anechoic content was detected during a routine ultrasound scan at 24 weeks of gestation in an asymptomatic 39‐year‐old woman with a singleton pregnancy. The cyst was aseptate, lacked mural blood flow and was not associated with ascites. It was located in the central abdominal area above and anterior to the uterus. Gradually increasing abdominal discomfort developed, and a laparotomy was performed at 27 weeks; the cyst was removed after aspiration of 6.3 L of serous fluid and the ipsilateral ovary was preserved. Pathological examination indicated a large luteinized follicular cyst of pregnancy. A healthy male infant was delivered vaginally at term. A rapidly enlarging ovarian mass in pregnancy poses significant diagnostic problems. Large luteinized cysts of pregnancy are uncommon and thought to involve stimulation by human chorionic gonadotropin (hCG), or increased tissue sensitivity to hCG. A literature search identified four previous cases that had been detected prenatally. With one exception, the cysts appeared to enlarge during pregnancy, eventually becoming symptomatic, and two previous cases also required removal of the cyst before birth. Adverse pregnancy outcome was only reported in one of the previous cases. In summary, large luteinized cysts of pregnancy are an uncommon type of cystic mass particular to pregnancy, characterized by the combination of a benign appearance and a tendency to enlarge rapidly, eventually becoming symptomatic and most often necessitating surgery. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Time‐resolved laser‐induced fluorescence spectroscopy as a diagnostic instrument in head and neck carcinoma
Authors: Meier Jeremy D. , Xie Hongtao , Sun Yang , Sun Yinghua , Hatami Nisa , Poirier Brian , Marcu Laura , Farwell D. Gregory 
Published: May 2010

ObjectiveThe objectives of this study were to 1) determine differences in lifetime fluorescence between normal and malignant tissue of the upper aerodigestive tract, and 2) evaluate the potential of time‐resolved laser‐induced fluorescence spectroscopy (TR‐LIFS) as a diagnostic instrument for head and neck squamous cell carcinoma (HNSCC).Study DesignCross‐sectional study.SettingUniversity‐based medical center.Subjects and MethodsNine patients with suspected HNSCC were included. In the operating room, a nitrogen pulse laser (337 nm, 700‐picosecond pulse width) was used to induce tissue autofluorescence of normal tissue and suspected malignant lesions. Spectral intensities and time‐domain measurements were obtained and compared with the histopathology at each site. A total of 53 sites were measured. The fluorescence parameters that provided the most discrimination were determined.ResultsDifferences in spectral intensities allowed for discrimination between malignant and normal tissue. The spectral intensity of malignant tissue was lower than that of normal tissue, and a shift of peak intensity to a longer wavelength was observed in the normalized spectrum of malignant tissue in the range of 360 to approximately 660 nm. Multiple time‐resolved fluorescence parameters provided the best diagnostic discrimination between normal tissue and carcinoma, including average lifetimes (i.e., at 390 nm: 1.7 ± 0.06 ns [not significant] for normal and 1.3 ± 0.06 ns for tumor, P = 0.0025) and the second‐order Laguerre expansion coefficient (LEC‐2) (i.e., at 460 nm: 0.135 ± 0.001 for normal and 0.155 ± 0.007 for tumor, P < 0.05).ConclusionThese findings highlight some of the differences in lifetime fluorescence between normal and malignant tissue. TR‐LIFS has potential as a noninvasive diagnostic technique for HNSCC.
Lymphatic malformations: Current cellular and clinical investigations
Authors: Perkins Jonathan A. , Manning Scott C. , Tempero Richard M. , Cunningham Michael J. , Edmonds Joseph L. , Hoffer Fredric A. , Egbert Mark A. 
Published: May 2010

ObjectiveSummarize current knowledge of lymphatic malformation development, biology, and clinical outcome measures.MethodsPanel presentation of lymphatic malformation biology and measurement of head and neck malformation treatment outcomes.ResultsCharacterization of lymphatic malformation endothelial and stromal cells may lead to biologically based treatment. Traditionally, lymphatic malformation treatment outcomes have been measured according to reduction of malformation size. Currently, methods to measure functional outcomes following lymphatic malformation treatment are lacking. This is particularly apparent when the malformation directly involves the upper aerodigestive tract.ConclusionsThe etiology and pathogenesis of head and neck lymphatic malformations are poorly understood, but understanding is improving through ongoing investigation. Reduction of lymphatic malformation size is generally possible, but further work is necessary to optimize methods for measuring therapeutic outcomes in problematic areas.
Outcome of surgical closure of nasal septal perforation
Authors: Wong S , Raghavan U 
Published: May 2010

AbstractObjective:To assess success rates and symptom control after surgical treatment of nasal septal perforation.Method:A prospective study was undertaken of 28 consecutive patients with symptomatic nasal septal perforation treated surgically by one surgeon between 2005 and 2007. All patients underwent an open rhinoplasty approach with bilateral superior and inferior nasal mucosal advancement flaps and acellular porcine collagen placed in between. Symptom severity was assessed pre- and post-operatively using a validated visual analogue score. The nasal valve angle was assessed pre- and post-operatively by two independent assessors.Results:Patients comprised 12 women and 16 men, with a mean age of 45 years (range: 21–76). The mean follow up was 16 months (range: 6–24). The mean vertical and horizontal diameters of the perforations were 22 mm (range: 10–35) and 27 mm (range: 10–37), respectively. Twenty-seven (96 per cent) patients had complete closure of nasal septal perforation. There were statistically significant differences between the pre- and post-operative mean visual analogue scale scores for epistaxis (p < 0.001), crusting (p < 0.001), whistling (p < 0.001) and nasal obstruction (p < 0.001). Epistaxis, crusting and whistling resolved in all patients, and 92 per cent reported improvement in nasal blockage.Conclusion:Closure of nasal septal perforation using an open rhinoplasty approach with nasal mucosal advancement flaps and a porcine collagen sandwich is a pertinent and reliable technique for the management of nasal septal perforation.
Maxillary sinusitis of dental origin due to oroantral fistula, treated by endoscopic sinus surgery and primary fistula closure
Authors: Hajiioannou J , Koudounarakis E , Alexopoulos K , Kotsani A , Kyrmizakis D E 
Published: May 2010

AbstractAim:To present the current treatment approach for oroantral fistula causing maxillary sinusitis.Design:Case series. Four cases of oroantral fistula (diameters: 6, 9, 11 and 13 mm) due to chronic maxillary sinusitis were treated by excision of all diseased oroantral fistula tissue, followed by endoscopic creation of a large middle antrostomy and closure of the fistula using buccal flaps. A synthetic surgical glue and local alveolar bone were used.Results:Patients were followed up for six months to three years; all were considered cured.Conclusion:Most surgeons use buccal or palatal flaps, combined with the Caldwell–Luc procedure, to treat chronic odontogenic sinusitis and to repair fistulae more than 5 mm in diameter. This study supports the hypothesis that an endoscopic technique could be successfully used in patients with oroantral fistula causing chronic maxillary sinusitis of dental origin, instead of the Caldwell–Luc procedure, at least in patients with a small to medium-sized oroantral fistula.
Tracheoesophageal fistula secondary to chemical trauma: is there a place for planned conservative management?
Authors: Biswas D , Majumdar S , Ray J , Bull P 
Published: May 2010

AbstractObjective:We present a unique case in which closure of a large tracheoesophageal fistula was achieved with planned conservative management.Method:The literature was reviewed for other documented cases of spontaneous closure of traumatic tracheoesophageal fistula.Results:Acquired tracheoesophageal fistula may result secondary to a chemical burn from an alkaline disc battery impacted in the oesophagus, particularly when the presentation, and thus diagnosis, are delayed. This condition is rare. The majority of such cases occur in children, and are conventionally managed with surgical repair. We found only three previously reported cases in which conservative management was attempted.Conclusion:Non-interventional management should be tried initially for the management of paediatric acquired tracheoesophageal fistula, to permit closure by secondary intention.
Long-term stenting for chronic frontal sinus disease: case series and literature review
Authors: Hunter B , Silva S , Youngs R , Saeed A , Varadarajan V 
Published: May 2010

AbstractObjective:The frontal sinus outflow tract consists anatomically of narrow channels prone to stenosis. Following both endonasal and external approach surgery, up to 30 per cent of patients suffer post-operative re-stenosis of the frontal sinus outflow tract, with recurrent frontal sinus disease. This paper proposes the surgical placement of a long-term frontal sinus stent to maintain fronto-nasal patency, as an alternative to more aggressive surgical procedures such as frontal sinus obliteration and modified Lothrop procedures.Design:We present a series of three patients with frontal sinus disease and significant co-morbidity, the latter making extensive surgery a significant health risk. We also review the relevant literature and discuss the use of long-term frontal sinus stenting.Results:These three cases were successfully treated with long-term frontal sinus stenting. Stents remained in situ for a period ranging from 48 to over 60 months.Conclusion:Due to the relatively high failure rates for both endonasal and external frontal sinus surgery, with a high post-operative incidence of frontal sinus outflow tract re-stenosis, long-term stenting is a useful option in carefully selected patients.
Potential distribution around a charged dust grain in an electronegative plasma
Authors: SHUKLA P. K. , STENFLO L. 
Published: May 2010

AbstractThe potential distribution around a charged dust grain in an electronegative plasma is obtained by using the appropriate dielectric susceptibilities for the Boltzmann distributed electrons and negative ions, and for the inertial positive ions that are streaming from the bulk plasma into the electronegative plasma sheath. The existence of oscillatory ion wakefields is shown. Positive ions are trapped/focused in the ion wakefields, and subsequently the negative dust particles are attracted to each other, forming ordered dust structures.
A closed-form algorithm for the least-squares trilateration problem
Authors: Zhou Yu 
Published: May 2010

SUMMARYTrilateration is the most adopted external reference-based localization technique for mobile robots, given the correspondence of external references. The nonlinear least-squares trilateration formulation provides an optimal position estimate from a general number (greater than or equal to the dimension of the environment) of reference points and corresponding distance measurements. This paper presents a novel closed-form solution to the nonlinear least-squares trilateration problem. The performance of the proposed algorithm in dealing with erroneous inputs of reference points and distance measurements has been analyzed through representative examples. The proposed trilateration algorithm has low computational complexity, high operational robustness, and reduced systematic error and uncertainty in position estimation. The effectiveness of the proposed algorithm has been further verified through an experimental test.
Fragmented authority from Ancien Régime to modernity: a quantitative analysis
Authors: DINCECCO MARK 
Published: May 2010

Abstract:This paper performs a systematic analysis that examines institutional fragmentation in terms of customs tariffs within states west of the Rhine from 1700 to 1815 and between states east of the Rhine from 1815 to 1871. Internal customs zones are measured in two ways: physical size and urban population. Both methods use 175 sample cities as described by De Vries (1984) in England, France, the Netherlands, and Spain as the basic unit of account. The results indicate that customs zones west of the Rhine were small prior to the French Revolution but grew dramatically from 1789 onwards. They thus provide definitive evidence of divided authority in Ancien Régime Europe. The measurement of external customs zones uses 117 sample cities in the German and Italian territories. The findings indicate a remarkable degree of institutional consolidation between states east of the Rhine over the 1800s.
Firms as social actors
Authors: ADELSTEIN RICHARD 
Published: May 2010

Abstract:This essay asks what firms are, whether they are ‘real’ social actors, and whether their actions can be traced without remainder to the actions of living people or whether there is some irreducible aspect of their existence or operation that must be attributed to the organization itself. It describes firms as ongoing, multilateral relational contracts from whose operation – that is, from performance over time by specific individuals in the roles and relationships defined by the contract – emerge the firm's idiosyncratic routines and capabilities. It emphasizes the role of entrepreneurs in the creation of firms and the close dependence of organizational capabilities on human performance, and argues that this account is consistent with a reasonable individualism that allows for social outcomes to be determined by the actions and interaction of individuals. It then proposes that firms are nonethelessinstitutional factsand thus ontologically subjective but epistemically objective components of reality, and concludes with directions for future work.
Stabilizing capping motif for β-hairpins and sheets
Authors: Kier Brandon L. , Shu Irene , Eidenschink Lisa A. , Andersen Niels H. 
Published: May 2010

Although much has been learned about the design of models of β-sheets during the last decade, modest fold stabilities in water and terminal fraying remain a feature of most β-hairpin peptides. In the case of hairpin capping, nature did not provide guidance for solving the problem. Some observations from prior turn capping designs, with further optimization, have provided a generally applicable, “unnatural” beta cap motif (alkanoyl-Trp at the N terminus and Trp-Thr-Gly at the C terminus) that provides a net contribution of 6 + kJ/mol to β-hairpin stability, surpassing all other interactions that stabilize β-hairpins including the covalent disulfide bond. The motif, made up entirely of natural residues, is specific to the termini of antiparallel β-strands and reduces fraying at the ends of hairpins and other β-sheet models. Utilizing this motif, 10- to 22-residue peptide scaffolds of defined stereochemistry that are greater than 98% folded in water have been prepared. The β-cap can also be used to staple together short antiparallel β-strands connected by a long flexible loop.