bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity measurement and compensation in spectral imaging
Authors: Ortyn William E. , Hall Brian E. , George Thaddeus C. , Frost Keith , Basiji David A. , Perry David J. , Zimmerman Cathleen A. , Coder David , Morrissey Philip J.
Published: September 2006

Background:

The ImageStream system combines advances in CCD technologies with a novel optical architecture for high sensitivity and multispectral imaging of cells in flow. The sensitivity and dynamic range as well as a methodology for spectral compensation of imagery is presented.

Methods:

Multicolored fluorescent beads were run on the ImageStream and a flow cytometer. Four single color fluorescent control samples of cells were run to quantify spectral overlap. An additional sample, labeled with all colors was run and compensated in six spectral channels.

Results:

Analysis of empirical data for sensitivity and dynamic range matched theoretical predictions. The ImageStream system demonstrated fluorescence sensitivity comparable to a PMT‐based flow cytometer. A methodology for addressing spectral overlap, individual pixel anomalies, and multiple imaging modalities was demonstrated for spectral compensation of K562 cells. Imagery is shown pre‐ and post‐compensation.

Conclusions:

Unlike intensity measurements made with conventional flow cytometers, object size impacts both dynamic range and fluorescence sensitivity in systems that utilize pixilated detection. Simultaneous imaging of alternate modalities can be employed to increase fluorescent sensitivity. Effective compensation of complex multimode imagery spanning six spectral bands is accomplished in a semi‐automated manner. © 2006 International Society for Analytical Cytology
Hyperspectral imaging system using acousto‐optic tunable filter for flow cytometry applications
Authors: Kasili Paul M. , Vo‐Dinh Tuan
Published: September 2006

A major advantage of flow cytometry is its flexible and open instrument configuration, which is highly suitable for systems integration. This flexibility permits the coupling of auxiliary instrumentation that may offer the measurement of parameters other than those typically measured by this multiparameter measurement technique. On the basis of this advantage, we explore the principle and application of hyperspectral imaging (HSI), which has the potential to be a useful add‐on feature to flow cytometry applications. Application of HSI to flow cytometry involves the acquisition of spatial information and rendering it in spectral form. In this work, we describe the development and application of an HSI system which provides both spectral and spatial information. Spectral information was generated by obtaining an entire spectrum of a single sample site within a wavelength region of interest, while spatial information was generated by recording a two‐dimensional (2D) image of an area of the sample of interest at one specific wavelength. HSI is a promising additional feature to flow cytometry since it can provide both spatial (image format) and spectral information in addition to the multiparameter information already available from flow cytometry measurements. © 2006 International Society for Analytical Cytology
Spectral analysis of the DNA targeting bisalkylaminoanthraquinone DRAQ5 in intact living cells
Authors: Njoh Kerenza L. , Patterson Laurence H. , Zloh Mire , Wiltshire Marie , Fisher Janet , Chappell Sally , Ameer‐Beg Simon , Bai Yanhong , Matthews Daniel , Errington Rachel J. , Smith Paul J.
Published: September 2006

Background:

We report on the potential DNA binding modes and spectral characteristics of the cell‐permeant far red fluorescent DNA dye, DRAQ5, in solution and bound within intact cells. Our aim was to determine the constraints for its use in flow cytometry and bioimaging.

Methods:

Solution characteristics and quantum yields were determined by spectroscopy. DRAQ5 binding to nuclear DNA was analyzed using fluorescence quenching of Hoechst 33342 dye, emission profiling by flow cytometry, and spectral confocal laser scanning microscopy of the complex DRAQ5 emission spectrum. Cell cycle profiling utilized an EGFP–cyclin B1 reporter as an independent marker of cell age. Molecular modeling was used to explore the modes of DNA binding.

Results:

DRAQ5 showed a low quantum yield in solution and a spectral shift upon DNA binding, but no significant fluorescence enhancement. DRAQ5 caused a reduction in the fluorescence intensity of Hoechst 33342 in live cells prelabeled with the UV excitable dye, consistent with molecular modeling that suggests AT preference and an engagement of the minor groove. In vivo spectral analysis of DRAQ5 demonstrated shifts to longer wavelengths upon binding with DNA. Analysis of spectral windows of the dual emission peaks at 681 and 707 nm in cells showed that cell cycle compartment recognition was independent of the far red–near IR emission wavelengths monitored.

Conclusions:

The study provides new clues to modes of DNA binding of the modified anthraquinone molecule in vivo, and its AT base‐pair selectivity. The combination of low quantum yield but high DNA affinity explains the favorable signal‐to‐noise profile of DRAQ5‐nuclear fluorescence. The robust nature of cell cycle reporting using DRAQ5, even when restricted spectral windows are selected, facilitates the analysis of encroaching spectral emissions from other fluorescent reporters, including GFP‐tagged proteins. © 2006 International Society for Analytical Cytology
Multispectral imaging in biology and medicine: Slices of life
Authors: Levenson Richard M. , Mansfield James R.
Published: September 2006

Multispectral imaging (MSI) is currently in a period of transition from its role as an exotic technique to its being offered in one form or another by all the major microscopy manufacturers. This is because it provides solutions to some of the major challenges in fluorescence‐based imaging, namely ameliorating the consequences of the presence of autofluorescence and the need to easily accommodate relatively high levels of signal multiplexing. MSI, which spectrally characterizes and computationally eliminates autofluorescence, enhances the signal‐to‐background dramatically, revealing otherwise obscured targets. While this article concentrates on examples derived from liquid‐crystal tunable filter‐based technology, the intent is to showcase the advantages of multispectral imaging in general. Some technologies used to generate multispectral images are compatible with only particular optical configurations, such as point‐scanning laser confocal microscopy. Band‐sequential approaches, such as those afforded by liquid‐crystal tunable filters (LCTFs), can be conveniently coupled with a variety of imaging modalities, which, in addition to fluorescence microscopy, include brightfield (nonfluorescent) microscopy as well as small‐animal, noninvasive in‐vivo imaging. Brightfield microscopy is the chosen format for histopathology, which relies on immunohistochemistry to provide molecularly resolved clinical information. However, in contrast to fluorescent labels, multiple chromogens, if they spatially overlap, are much harder to separate and quantitate, unless MSI approaches are used. In‐vivo imaging is a rapidly growing field with applications in basic biology, drug discovery, and clinical medicine. The sensitivity of fluorescence‐based in‐vivo imaging, as with fluorescence microscopy, can be limited by the presence of significant autofluorescence, a limitation which can be overcome through the utilization of MSI. © 2006 International Society for Analytical Cytology
Laser microdissection in translational and clinical research
Authors: Ladanyi Andras , Sipos Ferenc , Szoke Dominika , Galamb Orsolya , Molnar Bela , Tulassay Zsolt
Published: September 2006

Laser microdissection (LMD) is now a well established method for isolating individual cells or subcellular structures from a heterogeneous cell population. In recent years, cell, DNA, RNA, and protein based techniques has been successfully coupled to LMD and important information has been gathered through the analysis of the genome, transcriptome, and more recently the proteome of individual microdissected cells.

The aims of this review are to summarize and compare the principles of different laser microdissection instruments and techniques, to discuss sample preparation procedures for microdissection, and to provide wide variety of examples of translational/clinical research applications of LMD. Novel techniques specifically developed for the improved isolation of stained cells, living cells, or rare cells are also discussed.

LMD has become an indispensable tool in the preparation of homogenous samples for sophisticated cell or molecular assays. Despite major technological advances, the labor requirements of LMD are still relatively high. However, understanding the advantages and disadvantages of LMD technology and associated sample preparation procedures may aid in the earlier introduction of this method into the routine clinical diagnostics. © 2006 International Society for Analytical Cytology
A new configuration of the Zeiss LSM 510 for simultaneous optical separation of green and red fluorescent protein pairs
Authors: Anderson Kurt I. , Sanderson Jeremy , Gerwig Silke , Peychl Jan
Published: September 2006

The power and simplicity of genetically encoded fluorophores (fluorescent proteins, FPs) have drawn many molecular biologists to light microscopy. First generation FPs suffered from overlapping excitation and emission spectra, which limited their use together in pairs (Patterson et al., J Cell Sci 2001;114 (Part 5):837–838). Image acquisition and processing techniques, collectively known as linear unmixing, have been developed to separate overlapping fluorescence signals encountered in the imaging of FP pairs and also in FRET. These specialized techniques are not without their potential drawbacks, including limitations on sensitivity and time‐resolution for live cell imaging, and the risk of artifact in the hands of nonspecialists. With the advent of a new generation of red‐shifted FPs (Shaner et al., Nat Biotechnol 2004;22:1567–1572; Verkhusha and Lukyanov, Nat Biotechnol 2004;22:289–296) careful selection of excitation sources and emission filters obviate the need for linear unmixing when simple two channel imaging of FPs is required. Here we introduce a new configuration of the Zeiss LSM 510 laser scanning confocal microscope, optimized for live cell imaging of green fluorescent protein (GFP) together with spectral variants such as mRFP1 and mCherry using standard photo‐multipliers. A 2 mW, 594 nm HeNe laser was chosen as the excitation source for the red FP. This wavelength efficiently excites the aforementioned red variants without limiting the detection range of GFP emission during simultaneous two‐channel imaging. Compared to excitation of GFP and mCherry at 488 and 543 nm, excitation at 488 and 594 nm approximately doubles the sensitivity of GFP detection and eliminates bleed‐through of GFP into the mCherry channel. However, sensitivity of mCherry detection is decreased by 30%, suggesting the need for red FPs having longer emission peaks. Practical advantages to the simultaneous optical separation of FPs with nonoverlapping emission spectra include simplicity, robustness, reduced risk of artifact, and increased sensitivity during live cell imaging. © 2006 International Society for Analytical Cytology
The Remarkable Solvent‐Dependent Crystallization of the Mono‐ and Bis(4‐pyrrol‐1‐ylbenzonitrile) Adducts of Bis(pentafluorophenyl)zinc
Authors: Martin Eddy , Hughes David L. , Lancaster Simon J.
Published: September 2006

Treatment of a toluene solution of Zn(C6F5)2 with p‐C4H4N–C6H4CN yields (p‐C4H4N–C6H4CN)2Zn(C6F5)2, which has been structurally characterised following recrystallization from 1,2‐difluorobenzene by single‐crystal X‐ray diffraction and possesses the expected distorted tetrahedral molecular geometry. However, crystallization from dichloromethane yields a trigonal planar complex with only one p‐C4H4N–C6H4CN ligand. The three‐coordinate complex forms an intermolecular dimer in the solid state through a cooperative combination of zinc–arene, offset homoaromatic and dipole–dipole interactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Equilibrium modeling of removal of cadmium ions by olive stones
Authors: Calero de Hoces Mónica , Hernáinz Bermúdez de Castro Francisco , Blázquez García Gabriel , Tenorio Rivas Germán
Published: September 2006

This article addresses the equilibrium for cadmium biosorption using olive stones as a sorbent material over a range of temperatures between 25 and 80° C. Three models frequently used in the literature—Langmuir, Freundlich, and Redlich–Peterson—were examined to describe these equilibrium data. The experimental results fit Langmuir's model for the majority of temperatures tested. The maximal biosorption capacity, qm, increases with temperature, rising from 4.52 mg/g at 25° C to 9.72 mg/g at 80° C. Also, the affinity of olive stones for cadmium, represented by parameter b in Langmuir's model, increases when the temperature is raised from 25 to 80° C. Finally, the shape of Langmuir's model, represented by the dimensionless parameter KR, shows that cadmium biosorption with olive stones works well at the temperatures and initial cadmium concentrations tested in this study. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Interaction between cladding and structural frame observed in a full‐scale steel building test
Authors: Okazaki Taichiro , Nakashima Masayoshi , Suita Keiichiro , Matusmiya Tomohiro
Published: September 2006

Interaction between the external wall cladding and the seismic load resisting frame was examined in a full‐scale cyclic loading test of a three‐storey steel building structure. The building specimen had Autoclaved Lightweight Concrete (ALC, also designated as Autoclaved Aerated Concrete) panels installed and anchored to the structural frame as external wall cladding, using a standard Japanese method developed following the 1995 Kobe earthquake. ALC panelling is among the most widely used material for claddings in Japan. In the test, the ALC panel cladding contributed little to the stiffness and strength of the overall structure, even under a very large storey drift of 0.04 rad. No visible damage was noted in the ALC panels other than minor cracks and spalling of the bottom of the panels in the first storey. Consequently, in a Japanese steel building with properly installed ALC panel cladding, the structural frame is likely to be little affected by its cladding, and the ALC panels are capable of accommodating the maximum storey drift generally considered in structural design without sustaining discernible damage. Copyright © 2006 John Wiley & Sons, Ltd.
Seismic interaction in electrical substation equipment connected by non‐linear rigid bus conductors
Authors: Song Junho , Kiureghian Armen Der , Sackman Jerome L.
Published: September 2006

An important element within the power transmission lifeline is the electrical substation that typically consists of a complex set of equipment items interconnected through conductor buses or cables. If the connections are not sufficiently flexible, significant dynamic interaction may occur between the connected equipment items during a seismic event, which may result in damage and loss of the equipment. This paper investigates the interaction effect between electrical substation equipment items connected by non‐linear rigid bus conductors. The equipment items are modelled as single‐degree‐of‐freedom oscillators by use of appropriate shape functions. The hysteretic behaviours of rigid bus connectors are described by differential equation models fitted to experimental data. An efficient non‐linear random vibration method is used to quantify the seismic interaction effect of the connected equipment items. Based on the developed analytical models and method, the effect of interaction in the connected equipment system is investigated through extensive parametric studies. The results lead to practical charts and guidelines for the seismic design of interconnected electrical substation equipment. Copyright © 2006 John Wiley & Sons, Ltd.
Damage‐based design with no repairs for multiple events and its sensitivity to seismicity model
Authors: Das S. , Gupta V. K. , Srimahavishnu V.
Published: September 2006

Conventional design methodology for the earthquake‐resistant structures is based on the concept of ensuring ‘no collapse’ during the most severe earthquake event. This methodology does not envisage the possibility of continuous damage accumulation during several not‐so‐severe earthquake events, as may be the case in the areas of moderate to high seismicity, particularly when it is economically infeasible to carry out repairs after damaging events. As a result, the structure may collapse or may necessitate large scale repairs much before the design life of the structure is over. This study considers the use of design force ratio (DFR) spectrum for taking an informed decision on the extent to which yield strength levels should be raised to avoid such a scenario. DFR spectrum gives the ratios by which the yield strength levels of single‐degree‐of‐freedom oscillators of different initial periods should be increased in order to limit the total damage caused by all earthquake events during the lifetime to a specified level. The DFR spectra are compared for three different seismicity models in case of elasto‐plastic oscillators: one corresponding to the exponential distribution for return periods of large events and the other two corresponding to the lognormal and Weibull distributions. It is shown through numerical study for a hypothetical seismic region that the use of simple exponential model may be acceptable only for small values of the seismic gap length. For moderately large to large seismic gap lengths, it may be conservative to use the lognormal model, while the Weibull model may be assumed for very large seismic gap lengths. Copyright © 2006 John Wiley & Sons, Ltd.
Simplified seismic analysis of asymmetric building systems
Authors: Lin Jui‐Liang , Tsai Keh‐Chyuan
Published: September 2006

The paper reviews the uncoupled modal response history analysis (UMRHA) and modal pushover analysis (MPA) procedure in the analysis of asymmetric structures. From the pushover curves in ADRS format, showing the relationships of base shear versus roof translation and base torque versus roof rotation, a bifurcating characteristic of the pushover curves of an asymmetric structure is observed. A two‐degree‐of‐freedom (2DOF) modal stick is constructed using lump mass eccentrically placed at the end of beam which is connected with the column by a rotational spring. By converting the equation of motion of a whole structure into 2DOF modal equations, all of the elastic properties in the 2DOF modal sticks can be determined accurately. A mathematical proof is carried out to demonstrate that the 2DOF modal stick is consistent with the single‐degree‐of‐freedom (SDOF) modal stick at elastic state. The bifurcating characteristic of modal pushover curves and the interaction of modal translation and rotation can be considered rationally by this 2DOF modal stick. In order to verify the effectiveness of this proposed 2DOF modal stick, a two‐storey asymmetric building structure was analysed by the UMRHA procedure incorporating this novel 2DOF modal sticks (2DMPA) and conventional SDOF modal sticks (SDMPA), respectively. The analytical results are compared with those obtained by nonlinear response history analysis (RHA). It is illustrated that the accuracy of the rotational response histories obtained by 2DMPA is much better than those obtained by SDMPA. Consequently, the estimations of translational response histories on flexible side (FS) and stiff side (SS) of the building structure are also improved. Copyright © 2006 John Wiley & Sons, Ltd.
Non‐avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China
Authors: Xing Xu , Norell Mark A.
Published: September 2006

Over the past 10 years, numerous dinosaur specimens covering several major dinosaurian clades have been recovered from the Lower Cretaceous Jehol Group of western Liaoning. Among ornithischians from the Jehol Group, ornithopod fossils shed new light on the evolution of this largest ornithischian group; ankylosaurian discoveries add morphological diversity relevant to the highly specialized ankylosaurian body‐plan and ceratopsian occurrences offer a chance to study patterns of morphological change at the base of the Ceratopsia. The most significant discoveries are exceptionally well‐preserved theropod specimens covering most major coelurosaurian groups. Most theropod taxa from the Jehol Biota are the earliest, most basal members of coelurosaurian sub‐clades and provide substantial new information important for the reconstruction of coelurosaurian phylogeny and understanding the character evolution. The examination of character distributions along the coelurosaurian lineages reveals that the major structural modifications seen in birds were acquired sequentially and hierarchically early in coelurosaurian evolution. Most significantly, the Liaoning theropod discoveries advanced our understanding of two long‐debated evolutionary issues: the origin and early evolution of feathers and the origin of avian flight. The known distribution of the feather‐like integumentary structures and true feathers along the coelurosaurian lineages suggests that: (1) simple, filamentous integuments represent a primitive morph in feather evolution; (2) pennaceous feathers evolved early in maniraptoran evolution; and (3) feathers with aerodynamic features originated before the origin of birds. The presence of flight feathers on the metatarsus represents a new morph that is not known previously, but it has implications for understanding the origin of avian flight. The discovery of four‐winged dinosaurs was suggested to provide strong evidence supporting the ‘tree‐down’ hypothesis for the origin of avian flight, though in‐depth analysis and more data are needed to confirm this. A brief analysis of the fossil preservation and faunal composition reveals several interesting characteristics: (1) Volcanic activity might have contributed to the exceptional preservation of dinosaurian skeletons and in particular their soft tissues; (2) Different from most other dinosaur faunas, the Jehol dinosaur fauna has a low ornithischian specific diversity relative to a high theropod specific diversity; and (3) the Liaoning theropods show a strong tendency toward secondary herbivory. The faunal composition suggests a complex biogeographic history for this fauna and provides negative evidence for the hypothesis that eastern Asia was isolated from the Middle Jurassic through late Early Cretaceous times. Copyright © 2006 John Wiley & Sons, Ltd.
The mammal fauna in the Early Cretaceous Jehol Biota: implications for diversity and biology of Mesozoic mammals
Authors: Jin Meng , Yaoming Hu , Chuankui Li , Yuanqing Wang
Published: September 2006

Eleven species belonging to five major groups of mammals (multituberculates, eutriconodontans, ‘symmetrodontans’, metatherians and eutherians) have been described from the Jehol Biota, Liaoning, China. These fossils came from three horizons of the Yixian Formation: Lujiatun (lowest), Jianshangou and Dawahgzhangzi (highest) beds. Ages and correlations of these beds are still in debate, but are generally accepted as Early Cretaceous. Biostratigraphic distributions of some Jehol mammals corroborate the Early Cretaceous age of the biota. Many species are represented by skulls and articulated skeletons, although in most cases a species is known only from a single holotype that is squashed. These fossils furnish a wealth of morphological data for Mesozoic mammals, from which large character data sets have been amassed to generate competing higher‐level phylogenetic hypotheses of mammals. The Early Cretaceous divergence of eutherians is first documented as skull and skeletal fossils. The Jehol mammals indicate a diverse mammal fauna in which species range from 25 g to 14 000 g in body masses, have insectivorous, omnivorous and carnivorous diets (as reflected by their dentitions and by stomach content), and acquire scansorial, possibly arboreal and terrestrial habits (as inferred from articulated skeletons). The well‐preserved material helps to clarify some anatomical uncertainties in the study of early mammals, such as an ossified Meckel's cartilage as the occupant for the internal groove on the lower jaw of some Mesozoic species and a dental formula I3‐C1‐P3‐M4/i2‐c1‐p2‐3‐m5 for gobiconodontids as suggested by dentitions of several Jehol eutriconodontans. Evidence from cranial specimens of Jehol eutriconodontans also disfavours the brain‐expansion model for the detachment of middle ear ossicles from the dentary during evolution of mammals. Copyright © 2006 John Wiley & Sons, Ltd.
Metallurgical characterization, galvanic corrosion, and ionic release of orthodontic brackets coupled with Ni‐Ti archwires
Authors: Darabara Myrsini S. , Bourithis Lefteris I. , Zinelis Spiros , Papadimitriou George D.
Published: September 2006

In orthodontics, a combination of metallic alloys is placed into the oral cavity during medical treatment and thus the corrosion resistance and ionic release of these appliances is of vital importance. The aim of this study is to investigate the elemental composition, microstructure, hardness, corrosion properties, and ionic release of commercially available orthodontic brackets and Copper Ni‐Ti archwires. Following the assessment of the elemental composition of the orthodontic wire (Copper Ni‐Ti™) and the six different brackets (Micro Loc, Equilibrium, OptiMESHXRT, Gemini, Orthos2, and Rematitan), cyclic polarization curves were obtained for each material to estimate the susceptibility of each alloy to pitting corrosion in 1M lactic acid. Galvanic corrosion between the orthodontic wire and each bracket took place in 1M lactic acid for 28 days at 37°C and then the ionic concentration of Nickel and Chromium was studied. The orthodontic wire is made up from a Ni‐Ti alloy with copper additions, while the orthodontic brackets are manufactured by different stainless steel grades or titanium alloys. All tested wires and brackets with the exception of Gemini are not susceptible to pitting corrosion. In galvanic corrosion, following exposure for 28 days, the lowest potential difference (∼250 mV) appears for the orthodontic wire Copper Ni‐Ti and the bracket made up from pure titanium (Rematitan) or from the stainless steel AISI 316 grade (Micro Loc). Following completion of the galvanic corrosion experiments, measurable quantities of chromium and nickel ions were found in the residual lactic acid solution. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Biocompatibility of resin‐based dental materials applied as liners in deep cavities prepared in human teeth
Authors: de Souza Costa Carlos Alberto , Teixeira Hilcia Mezzalira , Nascimento Alexandre Batista Lopes do , Hebling Josimeri
Published: September 2006

Background: Since only a few data have been published concerning the effects of resinous dental materials on the pulp–dentin complex, the aim of this study was to evaluate the biocompatibility of resin‐based materials applied as liners in deep cavities prepared in human teeth. Methods: After preparing class V cavities, the following dental materials were applied on the axial walls: group 1, Vitrebond™ (VIT; 3M ESPE); group 2, Ultra‐Blend® Plus™ (UBP; Untradent); and group 3, Clearfil™ SE Bond (CSEB; Kuraray). In group 4 (control), the hard‐setting calcium hydroxide cement Dycal (CH; Caulk/Dentsply) was used. The teeth extracted at 7 days or between 30 and 85 days after the clinical procedures were processed for histological evaluation. Results: For all the experimental and control groups, most of specimens exhibited no pulpal response or slight inflammatory reaction associated with slight tissue disorganization at 7‐day period. Moderate inflammatory pulpal response occurred only in one tooth (RDT = 262 μm) of group 3 in which transdentinal diffusion of resin components was observed. Conclusion: The resin‐based dental cements VIT and UBP as well as the bonding agent CSEB presented acceptable biocompatibility when applied in deep cavities prepared in sound human teeth. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Influence of contamination on bonding to zirconia ceramic
Authors: Yang Bin , Scharnberg Michael , Wolfart Stefan , Quaas Anne C. , Ludwig Klaus , Adelung Rainer , Kern Matthias
Published: September 2006

The purpose of this study was to investigate the influences of contaminations and cleaning methods on bonding to dental zirconia ceramic. After saliva immersion and using silicone disclosing agent, airborne‐particle abraded ceramic specimens were cleaned with isopropanol (AL), acetone (AC), 37% phosphoric acid (PA), additional airborne‐particle abrasion (AA), or only with water rinsing (SS). Airborne‐particle abraded specimens without contaminations (CL) were used as control group. For chemical analysis specimens of all groups were examined with X‐ray photoelectron spectroscopy (XPS). Plexiglas tubes filled with composite resin were bonded to ceramic specimens using a phosphate‐monomer containing composite luting resin. After 3‐day water storage, tensile bond strengths (TBS) were tested. XPS analysis of group SS showed the presence of saliva and silicone (Si) contamination on the surface. The ratios of carbon/zirconium and oxygen/zirconium for groups PA and AA were comparable to those ratios obtained for group CL, indicating the removal of the organic saliva contamination. Airborne‐particle abrasion and acetone completely removed Si contamination from ceramic surfaces. Isopropanol had little cleaning effect on the two contaminants. TBS (median ± standard deviation) in MPa of the groups SS (11.6 ± 3.1), AL (10.0 ± 2.9), and AC (13.0 ± 2.8) were statistically lower than those of groups PA (33.6 ± 5.5), AA (40.1 ± 3.6), and CL (47.0 ± 8.1) (p < 0.001), while no differences were found in TBS between groups AA and CL (p > 0.5). Contamination significantly reduced bond strengths to zirconia ceramic. Airborne‐particle abrasion was the most effective cleaning method. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
A biodegradable copolymer for the slow release of growth hormone expedites scarring in diabetic rats
Authors: García‐Esteo Francisco , Pascual Gemma , Gallardo Alberto , San‐Román Julio , Buján Julia , Bellón Juan Manuel
Published: September 2006

In many diseases wound healing is impaired. This study was designed to establish whether the healing process in diabetes could be improved using a site‐specific polymer delivery system containing hGH. The system was first optimized in in vitro experiments performed on cultured fibroblasts taken from healthy and diabetic rats and then tested in an incisional wound model created in the diabetic Wistar rat. In the in vitro experiments using cultured fibroblasts, cell viability, growth, and proliferation were determined, along with polymer degradation, hormone release rates and the expression of TGFβ1 in the culture medium. For the in vivo experiments, polymer discs with/without GH were inserted through 3 cm incisions made on the backs of the animals. Wound specimens were obtained 7 and 30 days after surgery to evaluate inflammatory/apoptotic cells, metalloprotease expression and neoangiogenesis using microscopy and immunohistochemical techniques. The local administration of GH using a polymer delivery system did not affect the normal wound healing process. Conversely, when used in diabetic animals, epidermal and dermal repair was expedited. Our findings indicate that GH induces cell proliferation, enhances CD4+ infiltration; increases extracellular matrix protein deposition; stimulates angiogenesis; and diminishes apoptosis at the diabetic wound site. These effects give rise to a comparable wound healing process to that observed in healthy animals. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Deep rolling of titanium rods for application in modular total hip arthroplasty
Authors: Schuh Alexander , Zeller Christian , Holzwarth Ulrich , Kachler Werner , Wilcke Gerhard , Zeiler Günther , Eigenmann Bernd , Bigoney Jean
Published: September 2006

Compressive residual stresses are commonly introduced into the near‐surface regions of morse taper junctions of modular hip endoprostheses to prolong fatigue life. An increasing number of publications report that contamination of shot‐peened surfaces can lead to enhanced corrosion and third body wear. This study evaluates deep rolling of titanium alloy rods as a possible alternative to shot peening. Ten rods of Ti6Al7Nb alloy with a diameter of 15 mm were deep rolled with various rolling parameters. The resulting surface topography and residual contamination was analyzed using a scanning electron microscope (SEM). The near‐surface residual stress states after deep rolling were characterized by means of X‐ray diffraction. The roughness of the surfaces before deep rolling was about Rz = 14 μm, and after deep rolling surface roughness values of Rz 0.4–7.5 μm were achieved. The results of the SEM and EDAX analyses of the sample surface showed no evidence of surface contamination by particles or abrasion products caused by any process. At a pressure of 300 bar, compressive stress reached the maximum of −1150 MPa at a depth of 0.1 mm. Deep rolling thus allows a smooth and particle‐free surface to be obtained and therefore shows promise as a surface treatment for mating surfaces of morse tapers in modular hip endoprostheses. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
An fMRI study of somatosensory‐implicated acupuncture points in stable somatosensory stroke patients
Authors: Li Geng , Jack Clifford R. , Yang Edward S.
Published: September 2006

Purpose

To assess differences in brain responses between stroke patients and controls to tactile and electrical acupuncture stimulation using functional MRI (fMRI).

Materials and Methods

A total of 12 male, clinically stable stroke patients with left side somatosensory deficits, and 12 age‐matched male control subjects were studied. fMRI was performed with two different paradigms; namely, tactile stimuli and electrical stimulation at acupuncture points LI4 and LI11 on the affected side of the body. fMRI data were analyzed using SPM99.

Results

Tactile stimulation in both patients and controls produced significant activation in primary and secondary sensory and motor cortical areas and cerebellum. Greater activation was present in patients than controls in the somatosensory cortex with both the tactile task and the acupuncture point (acupoint) stimulation. Activation was greater during the tactile task than the acupuncture stimulation in patients and normal controls.

Conclusion

Differences observed between patients and controls on both tasks may indicate compensatory over recruitment of neocortical areas involved in somatosensory perception in the stroke patients. The observed differences between patients and controls on the acupoint stimulation task may also indicate that stimulation of acupoints used therapeutically to enhance recovery from stroke, selectively activates areas thought to be involved in mediating recovery from stroke via functional plasticity. fMRI of acupoint stimulation may illustrate the functional substrate of the therapeutically beneficial effect of acupuncture in stroke rehabilitation. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Delayed hyperenhancement patterns in occlusive and reperfused myocardial infarcts during different healing stages
Authors: Wang Yi , Sun Wei , Cao Guang , Meng Liang , Song Laifeng , Du Xiangke
Published: September 2006

Purpose

To investigate delayed hyperenhancement during different healing stages of myocardial infarct with and without reperfusion in a pig model.

Materials and Methods

Twelve pigs were studied. Six pigs were subjected to permanent right coronary artery (RCA) occlusion, and the other six were subjected to transient 90‐minute RCA occlusion. In vivo MRI including first‐pass perfusion and myocardial delayed enhancement (MDE) was performed at four, eight, 12, and 24 hours, and eight days after the artery occlusion. The MDE scan was repeated four times, two to 32 minutes after contrast administration.

Results

For all six pigs without reperfusion, the four‐hour MRI showed transmural perfusion defect and no delayed hyperenhancement; from eight hours on, delayed hyperenhancement appeared and its spatial extent gradually increased until it became transmural hyperenhancement at eight days. However, in all six pigs with reperfusion, hyperenhancement was present at every stage from four hours to eight days. Pathology confirmed the existence of infarct at various stages of healing irrespective of reperfusion status.

Conclusion

Occlusive hyperacute infarct did not exhibit any delayed hyperenhancement, which indicates that perfusion plays an important role in delayed enhancement at the hyperacute stage. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Spontaneous detorsion of the ovary: Can it be diagnosed by MRI?
Authors: Ghossain Michel A. , Hachem Kamal , Aoun Noël J. , Haddad‐Zebouni Soha , Mansour Fersan , Suidan Joseph S. , Abboud Joseph
Published: September 2006

Purpose

To determine whether recent progress in imaging has made it possible to diagnose spontaneous detorsion, which is an accepted concept in the gynecological literature but until now has been a presumptive diagnosis that could not be confirmed because of the lack of imaging proof.

Materials and Methods

We searched for patients who had a diagnosis of spontaneous detorsion on MRI between January 2000 and January 2003, and selected only patients who met a selection of strict criteria, including mainly enlargement and hyperintensity of ovarian stroma on T2‐weighted (T2W) images, clinical findings compatible with torsion and detorsion, and return of the stroma to normal size on follow‐up examinations. Other signs of torsion, such as tubal thickening, were appreciated but not mandatory. Clinical follow‐up for at least three years was available.

Results

Four patients met the study criteria. No stabilizing procedure was performed in the ovaries. One patient recurred and lost her ovary.

Conclusion

The diagnosis of torsion followed by spontaneous detorsion was made with high probability in a selected number of patients. The clinical management of such patients remains a matter of debate. Laparoscopy with oophoropexy would be useful for young patients in whom close follow‐up cannot be achieved. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Automated perfusion‐weighted MRI using localized arterial input functions
Authors: Lorenz Cory , Benner Thomas , Chen Poe Jou , Lopez Chloe Joan , Ay Hakan , Zhu Ming Wang , Menezes Nina M. , Aronen Hannu , Karonen Jari , Liu Yawu , Nuutinen Juho , Sorensen A. Gregory
Published: September 2006

Purpose

To investigate the utility of an automated perfusion‐weighted MRI (PWI) method for estimating cerebral blood flow (CBF) based on localized arterial input functions (AIFs) as compared to the standard method of manual global AIF selection, which is prone to deconvolution errors due to the effects of delay and dispersion of the contrast bolus.

Materials and Methods

Analysis was performed on spin‐ and gradient‐echo EPI images from 36 stroke patients. A local AIF algorithm created an AIF for every voxel in the brain by searching out voxels with the lowest delay and dispersion, and then interpolating and spatially smoothing them for continuity. A generalized linear model (GLM) for predicting tissue outcome, and MTT lesion volumes were used to quantify the performance of the localized AIF method in comparison with global methods using ipsilateral and contralateral AIFs.

Results

The algorithm found local AIFs in each case without error and generated a higher area under the receiver operating characteristic (ROC) curve compared to both global‐AIF methods. Similarly, the local MTT lesion volumes had the least mean squared error (MSE).

Conclusion

Automated CBF calculation using local AIFs is feasible and appears to produce more useful CBF maps. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Separation and quantitation of fructose‐6‐phosphate and fructose‐1,6‐diphosphate by LC‐ESI‐MS for the evaluation of fructose‐1,6‐biphosphatase activity
Authors: Mancini Francesca , Fiori Jessica , Cavrini Vanni , Andrisano Vincenza
Published: September 2006

An LC‐ESI‐MS method was developed for the identification and quantification of fructose‐1,6‐biphosphate (F1,6BP) and fructose‐6‐phosphate (F6P), respectively the substrate and the product of the enzymatic reaction catalysed by fructose‐1,6‐bisphosphatase (F1,6BPase). F1,6BPase, expressed predominantly in liver and kidney, is one of the rate‐limiting enzymes of hepatic gluconeogenesis and has become a target for the development of new drugs for type 2 diabetes. The two sugar phosphates were separated on a Phenomenex Luna NH2 column (150 mm×2.0 mm id) using the following mobile phase: 5 mM triethylamine acetate buffer/ACN (80 : 20) v/v in a linear pH gradient (from pH = 9 to 10 in 15 min) at the flow rate of 0.3 mL/min. The detection was performed with an IT mass spectrometer in negative polarity (full scan 100–450 m/z) and in SIM mode on the generated anions at m/z = 339 (F1,6BP) and m/z = 259 (F6P). Under the optimised final conditions, the method was validated for accuracy, specificity, precision (inter‐ and intradays RSD comprised between 1.0 and 6.3% over the range of concentrations used), linearity (50–400 μM), LODs (0.44 μM) and LOQs (1.47 μM), and the method was applied to F6P determination in the F1,6BPase catalysed hydrolysis of F1,6BP.
Low cost, robust, in‐house hardware for heart cutting two‐dimensional gas chromatography
Authors: Apps Peter
Published: September 2006

Natural materials are so complex that no single column can separate all of the components. Heart cutting 2‐D GC (GC‐GC) using a Deans switch provides maximum separation, but the requisite gas flow configurations have earned a reputation for being fiddly and time consuming to set up and tune, unless electronic gas controls and costly software are employed. A design for a vented Deans switch is presented that can be assembled in‐house from standard commercial components. A vent to atmosphere replaces the balancing resistor, which solves the problem of balancing the pressures and flows, and requires no compensation for changes in gas viscosity and back‐pressure during temperature programming. First and second dimension columns can both be run at optimum flow rates, even if they are of different diameters. Analyte detectability is preserved by cutting only the target fraction from the first column and transferring the whole of it to the second column. Cryotrapping the selected fraction allows cuts of any width, and transfer of analytes to the second column as sharp bands. I have applied the vented Deans switch–cold trap to the identification of flavour and fragrance compounds from South African plants and foods; cuts are very repeatable, and the detectability of trace components is enhanced. Its capabilities are demonstrated by examples from analyses of essential oils and flavour extracts.
Clinical variability in type I familial amyloid polyneuropathy (Val30Met): Comparison between late‐ and early‐onset cases in Portugal
Authors: Conceição Isabel , De Carvalho Mamede
Published: September 2006

We compared early‐ with late‐onset cases in 86 patients with familial amyloidotic polyneuropathy type I (FAP). Among these patients, 43 presented before age 50 (early‐onset) and 43 after this age (late‐onset). Sex and geographical distribution were similar, although a family history of the disorder was more frequent in early‐onset cases. In late‐onset disease, autonomic dysfunction was less frequent, but organ involvement and severe neuropathic pain were more frequent. Neurophysiological measurements were similar. FAP is a cause of neuropathy in elderly patients, in particular in those presenting with neuropathic pain. Muscle Nerve, 2006
Myeloid dendritic cells in inclusion‐body myositis and polymyositis
Authors: Greenberg Steven A. , Pinkus Geraldine S. , Amato Anthony A. , Pinkus Jack L.
Published: September 2006

Dendritic cells (DCs), immune system cells central to the development of immunity, have not previously been reported in muscle in inclusion‐body myositis (IBM). We performed immunohistochemical studies on muscle biopsy specimens from 50 patients using monoclonal antibodies that distinguish two classes of DCs, myeloid DC and plasmacytoid DC. In 17 of 20 IBM and 9 of 10 polymyositis (PM) specimens, myeloid DCs were present in substantial numbers, frequently surrounded and sometimes invading otherwise intact myofibers, and were part of dense collections of cells that included T cells. Dermatomyositis muscle had more plasmacytoid DCs than myeloid DCs, whereas IBM and PM had greater numbers of myeloid DCs. The stellate morphology of myeloid DCs in dense collections of cells that included T cells suggests local intramuscular antigen presentation in IBM and PM. Muscle Nerve, 2006
Rigidity and spasms from autoimmune encephalomyelopathies: Stiff‐person syndrome
Authors: Espay Alberto J. , Chen Robert
Published: September 2006

Stiff‐person syndrome (SPS) is a disorder characterized by progressive muscle rigidity with superimposed painful muscle spasms and gait impairment due to continuous motor activity. Evidence has accumulated in favor of SPS representing an autoimmune, predominantly encephalomyelopathic disorder resulting from B‐cell–mediated clonal production of autoantibodies against presynaptic inhibitory epitopes on the enzyme glutamic acid decarboxylase (GAD) and the synaptic membrane protein amphiphysin. Recognition of the clinical spectrum of SPS is important, particularly the upper‐limb, cervical, and cranial nerve involvement that occurs in paraneoplastic variants. The correlation between antibody levels and severity of disease offers evidence for a pathogenic role for the anti‐GAD and anti‐amphiphysin autoantibodies. The scarcity of neuropathological correlates stand in sharp contrast with the severity of the disability in affected individuals and suggests that functional impairment of inhibitory circuits without structural damage is sufficient to develop the full clinical spectrum of SPS. The rarity of this condition limits the feasibility of controlled clinical trials in the treatment of SPS, but the available evidence suggest that drugs that increase cortical and spinal inhibition such as benzodiazepines and drugs that provide immune modulation such as intravenous immunoglobulin, plasmapheresis, and prednisone are effective treatments. Muscle Nerve, 2006