bluuebunny/crossref_metadata_2025 huggingface dataset:
Nasal Augmentation using Injectable Alginate and Mesenchymal Stem Cells in the Rabbit
Authors: Park Dong-Joon , Choi Jin Hyun , Kim Yoo-Jung , Kim Jin-Hyung , Kim Ki-Taek
Published: October 2006

Background

The goal of this study was to evaluate the use of the autogenous mesenchymal stem cells (MSCs) impregnated in an injectable alginate gel containing platelet-rich plasma (PRP) for nasal augmentation in rabbit model.

Methods

Bone marrow–derived MSCs were isolated and expanded from New Zealand white rabbits. At confluence, the cells were mixed with sodium alginate solution. PRP was prepared from the rabbits and it was immediately mixed into the alginate–cell mixture. The cell–PRP–alginate mix was injected into a subcutaneous nasal area. Eight weeks after injection changes in facial contour, newly formed nasal hump was analyzed and the amount of chondroitin sulfate in tissue was measured.

Results

Augmented nasal dorsa maintained their original shape until harvest. Immunohistochemical staining revealed that the deposited matrix was composed of type II collagen and that it was distributed abundantly and widely in the connective tissue of the tissue generated. The amount of chondroitin sulfate (main component of the proteoglycan in cartilage) produced was significantly higher when MSCs and PRP-alginate were used.

Conclusion

Injectable PRP-alginate gel containing autologous mesenchymal stem cells may offer a useful means of facial soft tissue augmentation.
Reconstruction of Skull Base Defects after Minimally Invasive Endoscopic Resection of Anterior Skull Base Neoplasms
Authors: Leong Jern-Lin , Citardi Martin J. , Batra Pete S.
Published: October 2006

Background

The endoscopic resection of the cribriform plate during minimally invasive endoscopic resection (MIER) of the anterior skull base neoplasms may result in large anterior skull base defects. The objective of this study is to describe techniques for the management of skull base defects after MIER.

Methods

Retrospective analysis was performed on patients undergoing MIER and skull base reconstruction between April 2000 and August 2005.

Results

Fourteen patients underwent endoscopic resection of anterior skull base tumors and reconstruction during the study period. The mean age was 57.4 years (range, 26–84 years). The sex distribution was eight men and six women. The specific indications for resection included 11 malignant and 3 benign neoplasms. Ten patients received adjuvant therapy, and in two instances this occurred before surgery. In all instances, the dura was exposed; however, only 10 cerebrospinal fluid (CSF) leaks were encountered intraoperatively. Reconstruction of the skull base was successfully performed, most commonly in a multilayer fashion, using an array of materials including cartilage, fat, acellular dermal graft, and mucosal free grafts. Lumbar drain placement was used in seven cases for an average of 5.6 days. No postoperative CSF leaks occurred. The mean follow-up was 18.0 months (range, 1–56 months).

Conclusion

This report describes methods for the reconstruction of the skull base after MIER. Reconstitution of the skull base barrier can be achieved through application of principles for surgical repair of CSF rhinorrhea.
Compressive Biomechanical Properties of Human Nasal Septal Cartilage
Authors: Richmon Jeremy D. , Sage August , Wong Van W. , Chen Albert C. , Sah Robert L. , Watson Deborah
Published: October 2006

Background

Nasal septal cartilage is frequently used in nasal reconstruction and is a common source of chondrocytes for cartilage tissue engineering. The biomechanical properties of septal cartilage have yet to be fully defined and this limits the ability to compare it to the various alternative tissue-implant materials or tissue-engineered neocartilage. Given the unique structure and orientation of the septum within the nose, we sought to investigate anisotropic behaviors of septal cartilage in compression and correlate this to the concentration of glycosaminoglycans (GAG) and collagen within the cartilage.

Methods

Human nasal septal cartilage specimens were tested in confined compression, with each sample analyzed in a medial orientation and also either a vertical or caudal-cephalic orientation, with the order of tests randomized. The equilibrium confined compression (aggregate) modulus, HA0 and the permeability, kp, at different offset compression levels were obtained for each compression test. After testing, the cartilage samples were solubilized, and the concentrations of GAG and collagen were obtained.

Results

Forty-nine compression tests (24 medial, 12 vertical, 13 caudal-cephalic) were run on cartilage specimens obtained from 21 patients. There was a significant effect of orientation on compression modulus, HA0, with the vertical (0.7 ± 0.12 MPa) and caudal-cephalic (0.66 ± 0.01 MPa) orientations being significantly stiffer (p = 0.05) than the medial orientation (0.44 ± 0.04 MPa). There was a trend of an orientation effect on k at 15% offset compression (p = 0.12) and a borderline significant effect of orientation on k at 30% offset compression (p = 0.05), demonstrating the M orientation to be more permeable than both the vertical and caudal–cephalic orientations. Both univariate and multivariate analysis did not demonstrate a significant effect of order of compression, age, gender, thickness, dry/wet weight, GAG, or collagen on either HA0, or kp values (p > 0.05).

Conclusion

This study provides new information on the compressive properties of septal cartilage along different axes of compression. The results demonstrate that human septal cartilage is anisotropic; the compressive stiffness is higher in the vertical and caudal–cephalic orientations than in the medial orientation. Additionally, the medial orientation tends to have the greatest permeability. The data obtained in this study provide a reference to which various craniofacial reconstruction materials and tissue-engineered neocartilage can be compared.
Concurrent Endoscopic Sinus Surgery and Rhinoplasty
Authors: Kircher Matthew L. , Dutton Jay M.
Published: October 2006

Background

Concerns over increased surgical risk and associated complications have been reported regarding concurrent endoscopic sinus surgery (ESS) and rhinoplasty procedures. The aim of this study was to evaluate the overall safety of these concurrent procedures in our experience.

Methods

A chart review was performed on 48 consecutive patients undergoing concurrent ESS and rhinoplasty between January 1998 and January 2005 with a mean follow-up of 12 months. The extent of surgical procedures, revisions required, and postoperative complications were documented.

Results

Thirty-one (65%) women and 17 (35%) men ranging in age from 16 to 56 years with a mean age of 37 years were included in this study. Forty-five patients (93.7%) underwent a primary rhinoplasty procedure, whereas the other three (6.3%) underwent a revision rhinoplasty. Four patients required minor rhinoplasty revision procedures for a rhinoplasty revision rate of 4/48 or 8.3%. Complications noted in three separate cases included partial nasal obstruction, pain near osteotomy site, and localized infection for a complication rate of 3/48 or 6.3%.

Conclusion

In this study, rhinoplasty revisions did not appear to be related to the fact that ESS was performed at the same time as rhinoplasty. In addition, the only complication possibly attributed to a combined approach was a postoperative infection that developed in an insulin-dependent diabetic patient who underwent a rhinoplasty for functional reasons. Consequently, we recommend screening patients with poor wound healing factors in addition to those with acute exacerbations of chronic rhinosinusitis or severe chronic rhinosinusitis before performing concurrent ESS and rhinoplasty. In our experience, complications noted during concurrent ESS and rhinoplasty were minor, indicating the overall safe nature of this combined procedure when performed in appropriate patients.
Expression of Leukotriene C4 Synthase and Plasminogen Activator Inhibitor 1 Gene Promoter Polymorphisms in Sinusitis
Authors: de Alarcón Alessandro , Steinke John W. , Caughey Robert , Barekzi Elizabeth , Hise Kathleen , Gross Charles W. , Han Joseph K. , Borish Larry
Published: October 2006

Background

Studies have described polymorphisms in genes involved with both leukotriene synthesis and remodeling. Leukotriene C4 synthase (LTC4S) is the critical terminal pathway enzyme involved in regulation of cysteinyl leukotriene (CysLT) synthesis. An A-to-C base exchange in the promoter region of the LTC4S gene influences its expression. The plasminogen activator inhibitor (PAI) 1 gene is associated with tissue fibrosis. The presence of either 4G or 5G residues in the promoter region has been associated with altered transcription. The role of these polymorphisms was investigated in patients with sinusitis and polyps. We performed a prospective study of patients undergoing endoscopic sinus surgery at a university hospital between 1996 and 2004.

Methods

Demographic data and sinus tissue were collected from patients. Patients were classified into four groups: controls, chronic hyperplastic eosinophilic sinusitis (CHES), aspirin exacerbated respiratory disease (AERD), and chronic inflammatory sinusitis (CIS). DNA was analyzed for the LTC4S and the PAI-1 promoter polymorphisms using standard PCR techniques.

Results

There were 133 patients with 76 women and 57 men (mean age, 42 years). Sixty-six people were in the control group, 16 people were in the CIS group, 51 people were in the CHES group, and 22 people were in the AERD group. The LTC4S allelic frequencies were controls, A = 0.81 and C = 0.19; CIS, A = 0.73 and C = 0.27; CHES, A = 0.69 and C = 0.31; AERD, A = 0.67 and C = 0.33. The C allele was more frequent in CHES versus controls (p = 0.04). The PAI-1 allele frequencies were controls, 5G = 0.55 and 4G = 0.45; CIS, 5G = 0.47 and 4G = 0.53; CHES, 5G = 0.56 and 4G = 0.44; AERD, 5G = 0.54 and 4G = 0.46. Increased expression of the 4G allele of the PAI-1 gene was observed in CIS; however, this genetic variance between the four groups was not statistically different (p > 0.05).

Conclusion

There appears to be a genetic component that contributes to nasal polyp formation in sinusitis. Although the LTC4S polymorphism has previously been associated with aspirin-sensitive asthma, this is the first demonstration that the polymorphism is associated with CHES and this is independent of aspirin sensitivity.
Measurement of Water Loss in Human Nasal Mucosa
Authors: Miwa Masato , Nakajima Noriyuki , Matsunaga Mayumi , Watanabe Kensuke
Published: October 2006

Background

Regulation of the barrier function in the nasal epithelium seems to be affected by the pathogenesis of allergic rhinitis. The measurement of transepidermal water loss has proven to be an important noninvasive method for assessing the efficiency of the skin as a protective barrier. Although the nasal mucosal epithelium also has such a protective function, the precise mechanism still is unknown.

Methods

We studied the alteration of nasal mucosal water loss in the basal state and after the nontraumatic applications of physiological saline, hypertonic saline (10% NaCl), nasal barrier cream, and 10% glycerol on the mucosal surface of the inferior turbinate.

Results

We observed that nasal mucosal water loss was increased by hypertonic saline and decreased by nasal cream and glycerol.

Conclusion

For the first time, we showed the human nasal mucosal water loss both in the basal state and after topical application of various substances.
Physiological Change in Nasal Patency in Response to Changes in Posture, Temperature, and Humidity Measured by Acoustic Rhinometry
Authors: Lal Devyani , Gorges Melissa L. , Ungkhara Girapong , Reidy Patrick M. , Corey Jacquelynne P.
Published: October 2006

Background

Acoustic rhinometry has been used to assess nasal patency and to calculate nasal cavity volume. This study used acoustic rhinometry to assess changes in nasal patency after alterations in posture, unilateral mechanical obstruction, temperature, and humidity.

Methods

Eight healthy adult volunteer subjects underwent acoustic rhinometry during the following conditions: (1) sitting position (control), (2) supine position, (3) left lateral recumbent position, (4) nostril unilaterally mechanically blocked, (5) ice pack on neck, (6) drinking cold water, (7) drinking hot water, (8) nasal nebulizer, and (9) oxymetazoline decongestant.

Results

Two distinct patterns emerged based on the total nasal cavity volumes in response to the decongestant. Subjects with initial unilateral nasal cavity volumes near the mean had an expected increase in total volume after the topical decongestant administration. There were two subjects with initial volumes of 1 SD above the mean that had a paradoxical decrease in total volume in response to the decongestant. In all subjects, there was a significant decrease in the volume of each of the nasal cavities in response to ingestion of hot water at 1 minute. There was a significant decrease in the volume of the smaller of the two nasal cavities in response to nebulizer treatment and hot water ingestion at 5 minutes. Total nasal cavity volume changes were not significant for any of the variables.

Conclusion

Changes in nasal cavity volumes were detected by acoustic rhinometry after alterations in posture, unilateral mechanical obstruction, temperature, and humidity. Nebulizer treatment and hot water ingestion caused a significant decrease in nasal volume. The nose of a healthy patient was able to adapt to environmental and physiological changes to maintain a consistent total nasal volume within 15 minutes.
Collective Intelligence in Design
Authors: Hight Christopher , Perry Chris
Published: October 2006

In their introduction to this issue, Christopher Hight and Chris Perry define the idea of collective intelligence in its relationship to design practice and to broader technological and social formations. First they suggest a reformulation of practices around networked communication infrastructures as conduits for the new orchestrations of power that Antonio Negri and Michael Hardt detailed in their books Empire and Multitude. They then describe how such practices are often involved in the development of responsive sensing environments as new sites for manifesting the social organisations and communities made possible via telecommunications and the Internet. Lastly, they address how traditional boundaries of design disciplines and knowledge, from architecture to programming, are opening into complex co‐minglings of their respective isolated ‘intelligences’ into collectives capable of engaging these new sites, new briefs and new sorts of projects. Copyright © 2006 John Wiley & Sons, Ltd.
Collective Cognition: Neural Fabrics and Social Software
Authors: Tierney Therese
Published: October 2006

For decades, the MIT Media Lab has been a centre of innovative and highly influential research on emerging technologies, including responsive and interactive sensing systems, software programming and forms of artificial intelligence, and robotic design and communication systems for new forms of knowledge production and distribution. Therese Tierney writes about several aspects of the Media Lab's research, including the current work of John Maeda, as well as the work of collaborators such as CEB Reas and Ben Fry, who she argues are developing work in new and sophisticated directions. She positions this work within the larger thematic of collective intelligence by addressing the particularly social forms of practice and the necessary connection to intelligent software and sensing technologies. Copyright © 2006 John Wiley & Sons, Ltd.
The AADRL: Design, Collaboration and Convergence
Authors: Steele Brett
Published: October 2006

Brett Steele, former director of the Architectural Association's Design Research Laboratory (AADRL) and now director of the Architectural Association, reflects upon the DRL as a laboratory for the production of a different kind of student and teacher, and ultimately as a new model for architectural education. His ‘screenshots’ offer an informal image/text‐based window through which to browse the general atmosphere of that research endeavour. The DRL was also very active in employing outside specialists from a variety of disciplines including computer programming and robotics. These interests were situated within the DRL's much larger ambition of rethinking the very definition of research itself, not isolated in the purely reflective interests of history and criticism but based on the projective desires of innovation. Moreover, the organisation of these new laboratories of design life begin to resemble their objects of study. Copyright © 2006 John Wiley & Sons, Ltd.
Working with Wiki, by Design
Authors: Burrow Andrew , Burry Jane
Published: October 2006

Andrew Burrow and Jane Burry explain the use of online platforms, such as wiki, employed by the Spatial Information Architecture Laboratory (SIAL) at RMIT University in Melbourne. As they demonstrate, these platforms enable projects whose participants span the globe, in turn situating SIAL within an internationally distributed design research network incorporating diverse forms of expertise. This includes the academic research under way at SIAL, much of which is done collaboratively with various other design and research entities, as well as the international work of SIAL's director Mark Burry, who has been developing innovative design and fabrication methods for the completion of Gaudí's complex proposal for the Sagrada Família church. SIAL's wiki platform collapses geographic and temporal distance to allow geographically dispersed agents to collaborate in unprecedented ways, integrating widely diverse sets of knowledge into the design process. Copyright © 2006 John Wiley & Sons, Ltd.
Terminal nerve in the mouse‐eared bat (Myotis myotis): Ontogenetic aspects
Authors: Jastrow Holger , Oelschläger Helmut Hermann August
Published: October 2006

As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse‐eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid‐embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant smaller fiber bundles (sfb) originate from one or more smaller ganglia in the basal part of the rostral nasal septum. The fibers of the mfb and sfbs join in the posterior quarter of the nasal roof before reaching the central ganglion (M) located in the meninges medial to the olfactory bulb. From the mid‐fetal period onward, a thin TN fiber bundle with some intermingled perikarya connects M to the brain by penetrating its wall rostral to the olfactory tubercle. Additional smaller ganglia may occur in this region. The TN and its ganglia persist in postnatal and adult bats but the number of perikarya is reduced here. Moreover, the different potential functions of the TN are discussed briefly. Anat Rec Part A, 288A:1201–1215, 2006. © 2006 Wiley‐Liss, Inc.
Effects of task difficulty on use of advice
Authors: Gino Francesca , Moore Don A.
Published: October 2006

Although prior studies have found that people generally underweight advice from others, such discounting of advice is not universal. Two studies examined the impact of task difficulty on the use of advice. In both studies, the strategy participants used to weigh advice varied with task difficulty even when it should not have. In particular, the results show that people tend to overweight advice on difficult tasks and underweight advice on easy tasks. This pattern held regardless of whether advice was automatically provided or whether people had to seek it out. The paper discusses implications for the circumstances under which people will be open to influence by advisors. Copyright © 2006 John Wiley & Sons, Ltd.
Increased Enantioselectivity and Remarkable Acceleration of Lipase‐Catalyzed Transesterification by Using an Imidazolium PEG–Alkyl Sulfate Ionic Liquid
Authors: Itoh Toshiyuki , Matsushita Yuichi , Abe Yoshikazu , Han Shi‐hui , Wada Shohei , Hayase Shuichi , Kawatsura Motoi , Takai Shigeomi , Morimoto Minoru , Hirose Yoshihiko
Published: October 2006

Several types of imidazolium salt ionic liquids were prepared derived from poly(oxyethylene)alkyl sulfate and used as an additive or coating material for lipase‐catalyzed transesterification in an organic solvent. A remarkably increased enantioselectivity was obtained when the salt was added at 3–10 mol % versus substrate in the Burkholderia cepacia lipase (lipase PS‐C)‐catalyzed transesterification of 1‐phenylethanol by using vinyl acetate in diisopropyl ether or a hexane solvent system. In particular, a remarkable acceleration was accomplished by the ionic liquid coating with lipase PS in an iPr2O solvent system while maintaining excellent enantioselectivity; it reached approximately 500‐ to 1000‐fold acceleration for some substrates with excellent enantioselectivity. A similar acceleration was also observed for IL 1‐coated Candida rugosa lipase. MALDI‐TOF mass spectrometry experiments of the ionic‐liquid‐coated lipase PS suggest that ionic liquid binds with lipase protein.
Synthesis of Fluorine‐Containing N‐Benzyl‐1,2,3‐triazoles and N‐Methyl‐pyrazoles from Conjugated Alkynes.
Authors: Rama Rao V. V. V. N. S. , Lingaiah B. P. V. , Yadla R. , Shanthan Rao P. , Ravikumar K. , Swamy G. Y. S. K. , Narsimulu K.
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Highly Stereoselective Synthesis of TMS‐, Alkyl‐, or Aryl‐Substituted cis‐[3]Cumulenols via α‐Alkynylated Zirconacyclopentenes.
Authors: Liu Yuanhong , Gao Hongjun , Zhou Shaolin
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
3,3′‐Bimorpholine Derivatives as a New Class of Organocatalysts for Asymmetric Michael Addition.
Authors: Mosse Sarah , Laars Marju , Kriis Kadri , Kanger Tonis , Alexakis Alexandre
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Microwave‐Promoted One‐Pot Synthesis of 4H‐Thiopyrans from α,β‐Unsaturated Ketones via a Three‐Component Reaction.
Authors: Barthakur Madan G. , Chetia Apurba , Boruah Romesh C.
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of 1,3‐Selenazetidines and 4H‐1,3,5‐Oxadiazines Using Acyl Isoselenocyanates.
Authors: Koketsu Mamoru , Yamamura Yusuke , Ando Hiromune , Ishihara Hideharu
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Unlocking the Potential of Thiaheterohelicenes: Chemical Synthesis as the Key
Authors: Collins Shawn K. , Vachon Martin P.
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Ruthenium‐Catalyzed Ring‐Closing Metathesis: Recent Advances, Limitations and Opportunities
Authors: Conrad Jay C. , Fogg Deryn E.
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Simulations of the Dynamics of 18‐Crown‐6 and Its Complexes: From the Gas Phase to Aqueous Interfaces with Supercritical CO2 and a Room‐Temperature Ionic Liquid
Authors: Chaumont A. , Schurhammer R. , Vayssiere P. , Wipff G.
Published: October 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Fast‐response VHF pulsed 2 KW power amplifiers
Authors: Quine Richard W. , Eaton Gareth R. , Dillon Shane
Published: October 2006

A pulsed power amplifier operating at a nominal 250 MHz with 2 kW (+63 dBm) output was designed to meet the specifications for an application in a pulsed EPR (electron paramagnetic resonance) spectrometer and was built by Tomco Technologies of Adelaide, South Australia. Key design features were pulse fidelity for short (e.g., 40 ns) RF pulses, output noise blanking after the pulse, and output power linear with input power from very low levels up to 2 kW output. A summary of the specifications, design, and performance of the amplifier is presented. The 2 kW RF amplifier tested has approximately 12 ns rise times and 15 ns fall times, permitting the formation of approximately 40 ns RF pulses. It has negligible amplitude droop over microsecond‐long pulses and negligible phase change over microsecond long pulses. There was observable but small phase change during the rise and fall times of the pulse. Even for input pulses as short as 16 ns, the output pulse peaks at more than half of the rated power output. Application to measuring the free induction decays of triaryl methyl radicals in aqueous solution was demonstrated. © 2006 Wiley Periodicals, Inc. Concepts Magn Reson 29B: 185–190, 2006.
Why do citizens want to keep refugees out? Threats, fairness and hostile norms in the treatment of asylum seekers
Authors: Louis Winnifred R. , Duck Julie M. , Terry Deborah J. , Schuller Regina A. , Lalonde Richard N.
Published: October 2006

A social identity framework was employed to understand why people support the exclusionary treatment of refugee claimants (‘asylum seekers’) in Australia. Over and above individual difference effects of social dominance orientation and individuals' instrumental threat perceptions, insecure intergroup relations between citizens and asylum seekers were proposed to motivate exclusionary attitudes and behaviour. In addition, perceived procedural and distributive fairness were proposed to mediate the effects of social identity predictors on intergroup competitiveness, serving to legitimise citizens' exclusionary behaviours. Support for these propositions was obtained in a longitudinal study of Australians' social attitudes and behaviour. Small and inconsistent individual‐level effects were noted. In contrast, after controlling for these variables, hostile Australian norms, perceived legitimacy of citizen status, and threatening socio‐structural relations were strongly and consistently linked to intentions to support the harsh treatment of asylum seekers, and exclusionary attitudes and action at Time 2. Moreover, perceived procedural and distributive justice significantly mediated these relationships. The roles of fairness and intergroup socio‐structural perceptions in social attitudes and actions are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Convergent data sharpening for the identification and tracking of spatial temporal centers of lightning activity
Authors: Woolford Douglas G. , Braun W. John
Published: October 2006

This study presents an exploratory analysis of Ontario lightning and fire ignition data. Our main goal is to relate forest fire ignitions to lightning stroke occurrences. However, due to the sheer volume of the lightning data, as well as accuracy and missing data issues, changes to the data are required prior to any such investigation. Planning to employ cluster‐based point‐process methods in future lightning‐caused fire ignition models, we wish to cluster the lightning strokes in space‐time.

The data used is © 1992, 1994, 1997, Queen's Printer for Ontario, Canada, and was referenced under agreement with the Ontario Ministry of Natural Resources.

We propose a mode‐seeking clustering algorithm that is based on a convergent form of ‘data sharpening’ methods. Data sharpening is based on local constant regression and was introduced as a bias‐reduction method in kernel density estimation. Data sharpening nudges observations closer to their nearest local mode(s) at each iteration. We propose to iterate the algorithm until convergence, showing that the data will converge to either local or global modes.

The usefulness of the algorithm in the lightning context is threefold: first, the lightning data can be reduced to corresponding local spatial‐temporal modes; second, slight modifications result in a noise‐reduction method that can be applied to estimate short‐term spatial track(s) of lightning storm system(s); third, the sharpened data provide a means for a bootstrap‐based simulation of spatial lightning strike patterns. Numerical examples and comments on the algorithm's appropriateness related to the lightning application appear throughout. The study concludes by noting some of the further work to be done. Copyright © 2006 John Wiley & Sons, Ltd.
Consolidations and closures: an empirical analysis of exits from the hospital industry
Authors: D. Harrison Teresa
Published: October 2006

This paper investigates the pre‐exit characteristics of hospital mergers, acquisitions, and closures. We estimate competing risk hazard models using an 18‐year national data set that spans the wave of closures in the 1980s and of mergers in the 1990s. Evidence shows that weak productivity of the hospital is a strong determinant for closures while competitive pressures are more influential in the decision to consolidate. Thus, increased market power, relative to cost reductions, appears to play a larger role in the merger decision. Our results also provide insight into possible correlations between mergers and closures. Copyright © 2006 John Wiley & Sons, Ltd.
Macrophage behavior on multilayered DNA‐coatings in vitro
Authors: Van den Beucken J.J.J.P. , Walboomers X.F. , Vos M.R.J. , Sommerdijk N.A.J.M. , Nolte R.J.M. , Jansen J.A.
Published: October 2006

A pivotal factor to consider in the development of biomaterials and biomaterial coatings is the inflammatory response to these materials. The insertion of implants is followed by protein adsorption and subsequent interactions with cellular components of the biological surroundings, in which macrophages play a dominant role through the production of a myriad of signaling molecules. In view of this, the aims of the present study were to evaluate (i) gross protein adsorption to, and (ii) in vitro behavior of macrophages on novel biomaterial coatings, composed of poly‐D‐lysine (PDL) or poly(allylamine hydrochloride) (PAH) and DNA, and to compare these coatings with negative (noncoated glass) and positive controls (noncoated glass + LPS‐stimulation). The results demonstrate that multilayered DNA‐coatings do not affect gross protein adsorption compared to noncoated controls. Cell culture experiments showed that the attachment to, and viability and morphology of two types of macrophages cultured on multilayered DNA‐coatings is comparable to noncoated controls. Still, macrophages repeatedly showed decreased secretion levels of the proinflammatory cytokine TNF‐α on multilayered DNA‐coatings, whereas no differences were observed in the secretion of IL‐1β, IL‐10, and TGF‐β1. Appropriate animal studies are required to elucidate if these in vitro indications have clinical effects on the inflammatory and wound healing processes around implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Prolyl‐hydroxylase inhibition and HIF activation in osteoblasts promotes an adipocytic phenotype
Authors: Irwin R. , LaPres J.J. , Kinser S. , McCabe L.R.
Published: October 2006

Bone is a dynamic environment where cells sense and adapt to changes in nutrient and oxygen availability. Conditions associated with hypoxia in bone are also associated with bone loss. In vitro hypoxia (2% oxygen) alters gene expression in osteoblasts and osteocytes and induces cellular changes including the upregulation of hypoxia inducible factor (HIF) levels. Our studies show that osteoblasts respond to hypoxia (2% oxygen) by enhancing expression of genes associated with adipocyte/lipogenesis phenotype (C/EBPβ, PPARγ2, and aP2) and by suppressing expression of genes associated with osteoblast differentiation (alkaline phosphatase, AP). Hypoxia increased HIF protein levels, hypoxic response element (HRE) binding, and HRE‐reporter activity. We also demonstrate that prolyl‐hydroxylases 2 and 3 (PHD2, PHD3), one of the major factors coordinating HIF degradation under normoxic but not hypoxic conditions, are induced in osteoblasts under hypoxic conditions. To further determine the contribution of PHDs and upregulated HIF activity in modulating osteoblast phenotype, we treated osteoblasts with a PHD inhibitor, dimethyloxaloylglycine (DMOG), and maintained cells under normoxic conditions. Similar to hypoxic conditions, HRE reporter activity was increased and adipogenic gene expression was increased while osteoblastic genes were suppressed. Taken together, our findings indicate a role for PHDs and HIFs in the regulation of osteoblast phenotype. J. Cell. Biochem. 100: 762–772, 2007. © 2006 Wiley‐Liss, Inc.
p53 modulation of the DNA damage response
Authors: Helton E. Scott , Chen Xinbin
Published: October 2006

The tumor suppressor p53 plays a central role in the DNA damage response. After exposure to genotoxic stress, p53 can both positively and negatively regulate cell fate. Initially, p53 promotes cell survival by inducing cell cycle arrest, DNA repair, and other pro‐survival pathways. However, when cells accumulate DNA damage or demonstrate aberrant growth, p53 can direct the elimination of damaged cells. In this review, we will discuss the transcriptional‐dependent and ‐independent roles of p53 in regulating the DNA damage response. J. Cell. Biochem. 100: 883–896, 2007. © 2006 Wiley‐Liss, Inc.
Calcium signaling in non‐excitable cells: Ca2+release and influx are independent events linked to two plasma membrane Ca2+entry channels
Authors: Chakrabarti Ranjana , Chakrabarti Rabindranath
Published: October 2006

The regulatory mechanism of Ca2+influx into the cytosol from the extracellular space in non‐excitable cells is not clear. The “capacitative calcium entry” (CCE) hypothesis suggested that Ca2+influx is triggered by the IP3‐mediated emptying of the intracellular Ca2+stores. However, there is no clear evidence for CCE and its mechanism remains elusive. In the present work, we have provided the reported evidences to show that inhibition of IP3‐dependent Ca2+release does not affect Ca2+influx, and the experimental protocols used to demonstrate CCE can stimulate Ca2+influx by means other than emptying of the Ca2+stores. In addition, we have presented the reports showing that IP3‐mediated Ca2+release is linked to a Ca2+entry from the extracellular space, which does not increase cytosolic [Ca2+] prior to Ca2+release. Based on these and other reports, we have provided a model of Ca2+signaling in non‐excitable cells, in which IP3‐mediated emptying of the intracellular Ca2+store triggers entry of Ca2+directly into the store, through a plasma membrane TRPC channel. Thus, emptying and direct refilling of the Ca2+stores are repeated in the presence of IP3, giving rise to the transient phase of oscillatory Ca2+release. Direct Ca2+entry into the store is regulated by its filling status in a negative and positive manner through a Ca2+‐binding protein and Stim1/Orai complex, respectively. The sustained phase of Ca2+influx is triggered by diacylglycerol (DAG) through the activation of another TRPC channel, independent of Ca2+release. The plasma membrane IP3receptor (IP3R) plays an essential role in Ca2+influx, by interacting with the DAG‐activated TRPC, without the requirement of binding to IP3. J. Cell. Biochem. 99: 1503–1516, 2006. © 2006 Wiley‐Liss, Inc.
Improved myocardial tagging contrast in cine balanced SSFP images
Authors: Ibrahim El‐Sayed H. , Stuber Matthias , Schär Michael , Osman Nael F.
Published: October 2006

Purpose

To improve the tag persistence throughout the whole cardiac cycle by providing a constant tag‐contrast throughout all the cardiac phases when using balanced steady‐state free precession (bSSFP) imaging.

Materials and Methods

The flip angles of the imaging radiofrequency pulses were optimized to compensate for the tagging contrast‐to‐noise ratio (Tag‐CNR) fading at later cardiac phases in bSSFP imaging. Complementary spatial modulation of magnetization (CSPAMM) tagging was implemented to improve the Tag‐CNR. Numerical simulations were performed to examine the behavior of the Tag‐CNR with the proposed method, and to compare the resulting Tag‐CNR with that obtained from the more commonly used spoiled gradient echo (SPGR) imaging. A gel phantom, as well as five healthy human volunteers, were scanned on a 1.5T scanner using bSSFP imaging with and without the proposed technique. The phantom was also scanned with SPGR imaging.

Results

With the proposed technique, the Tag‐CNR remained almost constant during the whole cardiac cycle. Using bSSFP imaging, the Tag‐CNR was about double that of SPGR.

Conclusion

The tag persistence was significantly improved when the proposed method was applied, with better Tag‐CNR during the diastolic cardiac phase. The improved Tag‐CNR will support automated tagging analysis and quantification methods. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Strengths and weaknesses of dark‐lumen MR colonography: Clinical relevance of polyps smaller than 5 mm in diameter at the moment of their detection
Authors: Ajaj Waleed , Ruehm Stefan G. , Gerken Guido , Goyen Mathias
Published: October 2006

Purpose

To assess the clinical relevance of dark‐lumen MR colonography (MRC) for the detection of colorectal lesions using conventional colonoscopy (CC) and histopathologic examinations as reference standard.

Materials and Methods

A total of 72 patients underwent MRC and CC. MRC was performed using a contrast‐enhanced high spatial resolution T1 weighted 3D volumetric interpolated breathhold examination (VIBE)‐sequence. All removed colorectal lesions were evaluated by an experienced pathologist.

Results

CC confirmed 65 polyps less than 5 mm in diameter. Non of those lesions could be detected using MRC. Just two (4%) of the 49 removed lesions smaller than 5 mm showed signs of dysplasia. Additionally, CC confirmed 25 polyps between 6–15 mm in diameter (MRC 22). All those 25 lesions were removed in CC. Only four (16%) of those polyps showed signs of dysplasia and malignancy (11, 13, 13 and 15 mm).

Conclusion

Dark‐lumen MRC failed to detect all polyps smaller than 5 mm in diameter which are generally not clinically relevant at the moment of their detection and thus can be kept under surveillance. However, MRC as a non‐invasive imaging modality is a promising alternative to CC in the detection of clinically relevant polyps larger than 5 mm in diameter. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Whole‐body magnetization transfer contrast imaging
Authors: Boss Andreas , Martirosian Petros , Küper Klaus , Fierlbeck Gerhard , Claussen Claus D. , Schick Fritz
Published: October 2006

Purpose

To demonstrate the feasibility of whole‐body magnetization transfer (MT) contrast imaging.

Materials and Methods

Whole‐body MT imaging was performed on eight healthy volunteers and five patients (mean age = 40.5 ± 17.8 years) with diagnoses of dermatomyositis (N = 1), B‐symptoms with suspicion of paraneoplastic disease (N = 1), metastatic malignant melanoma (N = 1), and multiple sclerosis (MS) (N = 2). Measurements were carried out on a 1.5‐Tesla whole‐body MR scanner capable of parallel signal reception. A three‐dimensional (3D) gradient‐echo sequence (TR = 17 msec, TE = 4.8 msec, flip angle = 10°) was applied in combination with a Gaussian off‐resonance MT preparation pulse acting at an off‐resonance of 1.500 Hz with a 500° effective flip angle. Whole‐body images were constructed from five different body regions.

Results

In all subjects, whole‐body MT contrast images were obtained within less than 20 minutes of measuring time. The images showed sufficient diagnostic image quality to assess the patients' pathologies. The MT ratios (MTRs, in percent units) for the volunteers were as follows: white matter (WM) 51.1 ± 1.0, gray matter (GM) 42.2 ± 1.3, skeletal muscle (mean value of four muscle groups) 50.3 ± 2.1, liver 39.4 ± 3.2, spleen 31.8 ± 2.6, renal cortex 30.4 ± 1.9, and renal medulla 25.6 ± 1.3. The MTRs for the pathologies were as follows: skeletal muscle in dermatomyositis ∼30, metastases in malignant melanoma 30.7–36.0, uterus myoma 49.3, and MS lesions 30–40.

Conclusion

Our preliminary data indicate that MT contrast in whole‐body MRI is feasible, and may be useful for rapid whole‐body assessment of diseases that exhibit high contrast in MT imaging, such as MS and muscular disorders. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Model‐based registration for dynamic cardiac perfusion MRI
Authors: Adluru Ganesh , DiBella Edward V.R. , Schabel Matthias C.
Published: October 2006

Purpose

To assess the accuracy of a model‐based approach for registration of myocardial dynamic contrast‐enhanced (DCE)‐MRI corrupted by respiratory motion.

Materials and Methods

Ten patients were scanned for myocardial perfusion on 3T or 1.5T scanners, and short‐ and long‐axis slices were acquired. Interframe registration was done using an iterative model‐based method in conjunction with a mean square difference metric. The method was tested by comparing the absolute motion before and after registration, as determined from manually registered images. Regional flow indices of myocardium calculated from the manually registered data were compared with those obtained with the model‐based registration technique.

Results

The mean absolute motion of the heart for the short‐axis data sets over all the time frames decreased from 5.3 ± 5.2 mm (3.3 ± 3.1 pixels) to 0.8 ± 1.3 mm (0.5 ± 0.7 pixels) in the vertical direction, and from 3.0 ± 3.7 mm (1.7 ± 2.1 pixels) to 0.9 ± 1.2 mm (0.5 ± 0.7 pixels) in the horizontal direction. A mean absolute improvement of 77% over all the data sets was observed in the estimation of the regional perfusion flow indices of the tissue as compared to those obtained from manual registration. Similar results were obtained with two‐chamber‐view long‐axis data sets.

Conclusion

The model‐based registration method for DCE cardiac data is comparable to manual registration and offers a unique registration method that reduces errors in the quantification of myocardial perfusion parameters as compared to those obtained from manual registration. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Trends in daily rainfall in the Iberian Peninsula from 1951 to 2002
Authors: Rodrigo F. S. , Trigo Ricardo M.
Published: October 2006

An analysis of 22 sites of daily precipitation records over the period 1951–2002 for the Iberian Peninsula is presented. Annual and seasonal total precipitation (P), number of wet days (N), precipitation intensity (I), the 95th percentile (P95), and percentage of rain falling on days with rainfall above the 95th percentile (%) are investigated. The annual and seasonal trends for these variables and for all 22 rain gauges are analysed, using the Mann–Kendall statistic, and a linear regression model. Moreover, a t‐test is applied to the difference between the means of two subperiods, respectively 1951–1976 and 1977–2002. Principal results indicate a decreasing trend in P, I, and P95 for several northern and southern stations in winter; P, I, and P95 in some southern stations in spring, I and P95 in some southern stations in summer, and I in some northern and southern stations in autumn. The general behaviour is a decrease in the daily intensity of rainfall, while the number of wet days does not reveal pronounced changes. This pattern is valid for both annual and seasonal values of the indices. The decreasing trend found for I in winter and annual series for some localities may be related to the predominance of the positive phase of the North Atlantic Oscillation (NAO), but it is necessary to find other mechanisms for those stations and seasons not linked directly to NAO. Copyright © 2006 Royal Meteorological Society.
An evaluation of statistical models for downscaling precipitation and their ability to capture long‐term trends
Authors: Benestad R. E. , Hanssen‐Bauer I. , Førland E. J.
Published: October 2006

Large‐scale changes in the sea‐level pressure do not necessary reflect changes in the atmospheric moisture budget, and hence may not give a good representation of changes in precipitation as a result of a global warming. Statistical models that use both sea‐level pressure and large‐scale precipitation as predictors are evaluated for a number of locations in Fennoscandia. The statistical models in most cases were capable of capturing 60–80% of the year‐to‐year seasonal variations in precipitation, and a correlation analysis over independent data indicated predictive correlation scores in the range 0.2–0.5. A comparison between statistical models based on large‐scale precipitation, sea‐level pressure, and a mixture of these, indicated similar skills in terms of variance and predictive skill of inter‐annual variations. Analyses of their ability to capture recent precipitation trends reveal potential problems regarding reconstructing long‐term changes in the past. One explanation for the statistical models not giving similar past trend values as given by the station observations may be partly because the precipitation trends during the most recent 50 years are not well defined since the interval is not sufficiently long. This is supported by the fact that trend analysis for station observations based on two different data products, and different trend analysis strategies, do not correspond well with each other. An analysis for possible non‐stationarities between large and local spatial scales does not indicate any significant presence of non‐stationarities. Copyright © 2006 Royal Meteorological Society