bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium control of metamorphosis in polychaete larvae
Authors: Ilan Micha , Jensen Rebecca A. , Morse Daniel E.
Published: September 2005

The importance of Ca2+ in the control of metamorphosis of a marine invertebrate larva was investigated. An excess of [Ca2+] in the external medium induced metamorphosis of Phragmatopoma californica (polychaete) larvae in a concentration‐dependent manner. This effect is specific for calcium, and not simply the result of osmotic changes, as an excess of Mg2+ did not induce metamorphosis. Consistent with this finding, the calcium ionophore, A23187, also induced metamorphosis in a concentration‐dependent manner. Paradoxically, however, the aromatic compounds diltiazem, verapamil, D600, and nifedipine, known to block Ca2+ channels in other systems, also induced metamorphosis. When exposed to diltiazem for only 20 h and subsequently washed free of this compound, 95% of the larvae metamorphosed and developed normally. Previous studies have demonstrated that the induction of metamorphosis in Phragmatopoma californica is controlled by chemosensory recognition of an exogenous morphogen and mediated by an excitatory pathway that involves adenyl cyclase and cyclic AMP. Because cellular excitation and cyclic AMP‐dependent signal transduction generally involve the participation of calcium ion, the most parsimonious explanation for the results reported here include (1) direct control of the morphogenetic pathway by calcium ion, and (2) complexities of the calcium regulation of this process, or a functional similarity between the structurally related aromatic effectors tested and the natural inducer of metamorphosis. © 1993 wiley‐Liss, Inc.
Locations of the ectodermal and nonectodermal subdivisions of the epiblast at stages 3 and 4 of avian gastrulation and neurulation
Authors: Garcia‐Martinez Virginio , Alvarez Ignacio S. , Schoenwolf Gary C.
Published: September 2005

A prospective fate map of the avian epiblast at late gastrula and early neurula stages has been generated through the construction of quail/chick transplantation chimeras. This map shows the subdivisions of the prospective ectoderm, mesoderm, and endoderm, both within the epiblast prior to their ingression and within the primitive streak. The map demarcates the locations and extents of the prospective surface ectoderm, otic placodes, neural crest, and neural plate‐including its postnodal levels—in prospective ectoderm of the epiblast; prospective foregut, within the prospective endoderm of the epiblast and primitive streak; and prospective notochord, somites, intermediate mesoderm, lateral plate mesoderm, and extraembryonic mesoderm in the prospective mesoderm of the epiblast and/or primitive streak. Prospective cardiogenic cells are apparently absent from the primitive streak at these stages, and contributions of the epiblast to the heart are relatively scant and inconsistent with the expected timing and directions of migrations of prospective cardiogenic cells. Mapping of the primitive streak at earlier stages in another study (García‐Martinez and Schoenwolf: Developmental Biology, in press) reveals that the ingression of cardiogenic cells through the primitive streak occurs prior to late gastrula stages, suggesting that contributions of epiblast to the heart at later stages are artifactual. Tests of prospective potency, based on the projected locations of origin of various cell groups provided by the new prospective fate map, are underway. © 1993 wiley‐Liss, Inc.
Formation of distal structures from stumps of chick wing buds at stages 24–25 following the grafting of quail tissue from X‐irradiated distal limb buds
Authors: Watanabe A. , Ohsugi K. , Ide H.
Published: September 2005

To examine the regulatory activity of the proximal region of chick limb buds, distal halves of chick wing buds at stages 24–25 were removed, and the distal tips of X‐irradiated stage 21 quail limb buds with an apical ectodermal ridge (AER) were grafted onto the chick stumps. The host stumps formed only humerus after removal of the donor distal tips or with tip mesoderm alone. However, when distal tips with an AER were grafted onto the stumps, one or two cartilage elements of host origin were formed at the distal end of the humerus.

To examine whether the stump cells have changed to cells of a more distal, progress zone (PZ) cells, the chick stumps with quail tips were immunostained with antibody against AV‐1, which reacts with the anterior PZ region of chick limb buds and is specific for an antigen that is expressed under the control of the AER. Within two days of grafting, cells positive for the antigen reapperaed in the stump tissues.

These results suggest that the some of the stump cells may be converted to PZ cells and their positional values may change to those of more distal structures under the influence of the AER. © 1993 wiley‐Liss, Inc.
Tests of the ability of two‐cell mouse embryos to utilize selected precursors of phosphoenolpyruvic acid and pyruvic acid
Authors: Shirley Barbara
Published: September 2005

Phosphoenolpyruvic acid and pyruvic acid are among the few compounds that two‐cell mouse embryos have been found capable of using as energy sources; most of the compounds in the glycolytic pathway and Krebs cycle that have been tested have been found unusable. Because 3‐phosphoglyceric acid of the compound converted most directly to phosphoenolpyruvic acid in glycolysis, one objective of this study was to examine whether it could support development of two‐cell embryos as phosphoenolpyruvic acid can. An additional objective was to examine whether alanine or serine, two amino acids that in later stages of development are converted to pyruvic acid for entry into the Krebs cycle, could support development of two‐cell embryos as pyruvate does. Two‐cell embryos were obtained from the oviducts of mice (C57BL × CBA) and were cultured in medium that contained 3‐phosphoglyceric acid, alanine, or serine in lieu of the pyruvate, lactate, and glucose usually contained in the medium. The embryos failed to undergo cleavage but this was not attributable to only a single energy source having been provided; embryos developed in a medium that provided only pyruvate. The results suggest that mouse embryos at the two‐cell stage of development are either unable to transport 3‐phosphoglyceric acid, alanine, and/or serine or are unable to convert the compounds to chemically similar ones; phosphoenolpyruvic acid or pyruvic acid, which can be metabolized by two‐cell mouse embryos. The results offer additional evidence that compounds more than one step removed from pyruvate in metabolic pathways are not used by two‐cell mouse embryos and, furthermore, suggest that the embryos cannot use alanine even though it is but a single step removed from pyruvate. © 1993 wiley‐Liss, Inc.
Production of viable haploid Oreochromis mossambicus gynogens using UV‐irradiated sperm
Authors: Varadaraj K.
Published: September 2005

Haploid and homozygous diploid mitotic gynogens of Oreochromis mossambicus were successfully produced using UV‐irradiated sperm. Optimum UV‐irradiation duration required for the production of 100% haploid was 10 min. Irradiation for more than 15 min caused loss of motility in sperm. Normal homozygous diploid mitotic gynogens were produced by heat shocking 70 min old activated haploid eggs. Haploids had 22 chromosomes, including a large subtelocentric chromosome; diploid mitotic gynogens had 44 chromosomes, including a pair of large subtelocentric chromosomes. Ratio of nuclear volume of haploid fish RBCs to diploid RBCs was 0.53:1, whereas that of relative DNA content was 0.4:1. Haploids were viable; however, they suffered from characteristic syndromes like poorly developed retina, twisted edematous body and curved tail. There was also a reduction in the number of vertebrae in the caudal region of haploids; only 4–5% eventually survived. These observations indicate that the syndrome characters and the lower rate of survival in haploid O. mossambicus may be more due to the absence of normal genes in pairs in homologous or heterologous chromosomes rather than due to the presence of lethal genes. © 1993 wiley‐Liss, Inc.
Tissue specificity of arthropod tropomyosin
Authors: Miyazaki Jun‐Ichi , Yahata Kensuke , Makioka Toshiki , Hirabayashi Tamio
Published: September 2005

In order to elucidate whether tropomyosin isoforms have different tissue‐specific functions, we examined tissue specificity of tropomyosin by two‐dimensional gel electrophoresis and immunoreplica tests using three arthropod species. These arthropods showed molecular heterogeneity and tissue specificity of tropomyosin in muscle and nonmuscle tissues. The beetle (Insecta) and centipede (Chilopoda) had three different isoforms. The scorpion (Arachnida) had six isoforms, two of which were nonmuscle‐specific. In addition to these isoforms, all the species contained nonmusclespecific isoforms of high electrophoretic mobilities and another isoform with a high electrophoretic mobility was found in the beetle heart and intestine. We summarized the results including the data from our previous studies on the horseshoe crab (Merostomata) and five crustaceans (Crustacea) and found that most isoforms were not shared by every tissue but detected in some particular tissues. In that sense, they were tissue specific, but each of them was not restricted to a single tissue. However, crustacean cardiac isoforms were contained exclusively in the hearts, and some of the nonmuscle isoforms were not found in other tissues; thus they were tissue specific in the strict sense. Considering our results and those on vertebrate tropomyosin together, we suggest that the existence of different isoforms alone does not imply straightforwardly different functions among the isoforms and that only strictly tissue‐specific isoforms can be assumed to have functions peculiar to their tissues. © 1993 wiley‐Liss, Inc.
Subcutaneous compliance and gravitational adaptation in snakes
Authors: Lillywhite Harvey B.
Published: September 2005

Previous studies have implicated morphological adaptations as important countermeasures to gravitational stresses on the circulatory systems of arboreal or climbing snakes. Such features include tight skin and relatively non‐compliant tissue compartments that oppose edema formation, but these traits have not been previously studied quantitatively. To provide information on this subject, interstitial fluid pressures were measured in eleven species of snakes using slit‐end catheters positioned in subcutaneous tissue located at the base of the tail. Interstitial pressures in all species were typically 0 to + 2 mm Hg in normally hydrated tissue, but varied widely when snakes were active or when the tail was curved at the site of measurement. Local compliance of the free fluid space was determined from measurements of pressure while saline was infused via the catheter tip. Such measurements varied from 0.18 μl/mm Hg inPhilodryas baroni, an arboreal species, to 2.3 μ/mm Hg inCrotalus adamanteus, a ground‐dwelling, terrestrial species. In general, compliance of the subcutaneous tissue space was greatest (P< 0.05) in non‐climbing and aquatic species of snakes that do not face problems of gravitational edema in dependent tissues. Presumably, the compliance measurements reflect adaptive structural differences related to requirements for counteracting gravitational stresses in the various species. © 1993 Wiley‐Liss, Inc.
D‐glucose transporter on mussel mantle cell membranes: Effect of sodium and phlorizin
Authors: Louzao M. C. , Vieytes M. R. , Botana L. M.
Published: September 2005

We studied the kinetics of the glucose transporter in mussel mantle cells. The transport is sodium dependent, with a very low uptake of glucose when sodium is replaced with potassium, choline or sucrose. In the presence of phlorizin, a glucose transporter inhibitor, the uptake is greatly diminished, with a low glucose uptake which is probably due to passive diffusion. The Woolf‐Augustinsson‐Hofstee plot obtained with different concentrations of glucose, and the Hill coefficient obtained in studies about the effect of Na+ on glucose uptake, indicate that more than one sodium ion was involved in the transport of each molecule of glucose across the membrane in mussel mantle cells, or that positive cooperativity is occurring. The activity of the transporter is not affected by the sodium‐proton pump inhibitor amiloride. © 1993 Wiley‐Liss, Inc.
Cloning of a crustacean myosin heavy chain isoform: Exclusive expression in fast muscle
Authors: Cotton Julie L. S. , Mykles Donald L.
Published: September 2005

A clone of a fast isoform of myosin heavy chain (HC) gene was isolated from a cDNA

The sequence data for this cDNA has been submitted to GenBank; the accession number is U03091.

expression library made from mRNA purified from the deep abdominal flexor muscle of the lobster, Homarus americanus. The cDNA (1.5 kb) contained the 3′ untranslated region (UTR) and the coding sequence for the last 413 amino acid residues of the carboxyl terminus of the polypeptide. The deduced amino acid sequence showed high homology with that of myosin HCs from Drosophila (73% identity), nematode (57% identity), and vertebrates (49% identities). Hydropathy plots showed a 28‐amino acid periodicity that is consistent with the α‐helical coiled coil structure of the rod region of native myosin. Northern blot analysis and in situ hybridization showed that the fast myosin HC isoform was expressed only in fast fibers; the probes did not hybridize to mRNA from slow fibers. The message consisted of a single transcript of 6.6 kb. The intracellular localization of the fast myosin mRNA was not uniform. The mRNA was largely confined to the intermyofibrillar spaces and to the subsarcolemmal cytoplasm of the fiber periphery and large infoldings of the cell membrane. Within these regions the mRNA was concentrated in the cytoplasm immediately surrounding the nuclei. This constitutes the first report of the cloning and expression of a myosin HC gene from a crustacean species. © 1993 Wiley‐Liss, Inc.
Isolation, immunochemical detection, and observations of the instability of vitellogenin from four teleosts
Authors: Silversand Christer , Hyllner Sven Johan , Haux Carl
Published: September 2005

Vitellogenin was purified from plasma of estradiol‐17β‐treated cod (Gadus morhua) rainbow trout (Oncorhynchus mykiss), turbot (Scophthalmus maximus), and wolffish (Anarhichas lupus) by precipitation with EDTA:Mg2+, distilled water, and high‐performance ion‐exchange chromatography. Vitellogenin of high purity was obtained by precipitation followed by chromatography, as evaluated by an homologous antiserum developed for each species. The instability of vitellogenin demanded consistent low temperature and the use of protease inhibitor before blood sampling. When the necessary precautions were taken, vitellogenin from rainbow trout, turbot, and wolffish eluted as one regular peak during chromatography. Cod vitellogenin eluted as two peaks and these demonstrated identical migration patterns on SDS‐PAGE. The observed differences in stability between the four species suggest that isolation procedures should be modified according to the requirements for each species. Electrophoresis of plasma from treated fish revealed the presence of several smaller proteins, with a molecular mass around 50 kDa, that were considered to be vitelline envelope proteins. Other minor plasma proteins were immunoreactive to antisera, directed against vitellogenin and therefore judged to be fragments of degraded vitellogenin. © 1993 Wiley‐Liss, Inc.
Induction of metamorphosis in landlocked sea lampreys, Petromyzon marinus
Authors: Holmes John A. , Youson John H.
Published: September 2005

Landlocked larval sea lampreys (Petromyzon marinus) in three size‐groups were treated with two concentrations of potassium perchlorate (0.01 and 0.05% KC104; a goitrogen) for 117 days during the winter to determine if metamorphosis can be induced at a time when it will not occur spontaneously and whether a minimum size (length and weight) and physiological condition, measured as a condition factor (CF), are necessary for induction to occur. Metamorphosis was induced in all size‐groups with both concentrations of KC1O4 but not in control animals. Size‐group was the only factor that significantly influenced (P < 0.05) the incidence of metamorphosis, which was 22% (13/60) in the 65–95 mm group, 52% (31/60) in animals 110–119 mm long, and 98% (59/60) in animals >130 mm long. Metamorphosing animals were significantly larger (P < 0.05) in size (length and weight) and had significantly higher (P < 0.05) CFs than unmetamorphosed larvae. The mean (±SEM) CFs of metamorphosing animals in the three size‐groups were 1.22 ± 0.04 (65–95mm), 1.25 ± 0.02 (110–119 mm), and and 1.27 ± 0.02 (>130 mm) and the smallest animal to metamorphose was 84 mm and 0.71 g in size. Minimum size and CF criteria for spontaneous metamorphosis (120 mm, 3.0 g, 1.50 CF) in landlocked sea lampreys are not necessary prerequisites for inducing metamorphosis using KC1O4. The experimental production of metamorphosis in sea lampreys of various sizes creates a valuable tool for studying hormonal and genetic regulation of this developmental strategy in a vertebrate of ancient lineage. © 1993 Wiley‐Liss, Inc.
Sperm are stored in the ovary of Lacuna (Epheria) variegata (carpenter, 1864) (gastropoda: Littorinidae)
Authors: Buckland‐Nicks John , Darling Patricia
Published: September 2005

Sperm are stored in the ovary of Lacuna (Epheria) uariegata (Carpenter, 1864) between oocytes or oriented with follicle cells singly or in clumps. The sperm develop close associations with follicle cells and in some cases become embedded in invaginations of cell apices. Follicle cells are rich in rough endoplasmic reticulum and are generally considered to provide nutrients to developing oocytes. The storage of sperm in the ovary was previously unknown for any gonochoric gastropod. The existence of sperm storage in the ovary of L. variegata has implications for both the site of fertilization and for sperm capacitation in this genus. The subfamily Lacuninae represent a monophyletic clade comprising five genera. This clade was previously characterized partly by a long duct to the seminal receptacle in two genera and by the eventual loss of the seminal receptacle with sperm storage in the oviduct in three others, including Lacuna. Storage of sperm in the ovary is an important new character that will enable further distinction among species of this unusual clade. © 1993 Wiley‐Liss, Inc.
Organic solute permeability in erythrocytes of the little skate, Raja erinacea
Authors: Russell Rebecca L. , Cauble Ginger D. , Goldstein Leon
Published: September 2005

Neutral, organic molecules with seven or less major atoms permeate erythrocytes of the little skate (Raja erinacea.) Hypotonicity (80%) increased permeation up to 10‐fold. Under both isotonic and hypotonic conditions solute influx occurred with the same size limitation, indicating that the number of permeation sites, but not their size, increases with hypotonicity. The maximum average diameter of these neutral molecules that penetrate the cell membrane is about 5.6 to 6.2 Å. This is similar to that found previously for amino acid permeation, but unlike amino acids, the entry of most of the organic, neutral molecules into skate erythrocytes is not affected by Band 3 inhibitors. These results suggest that the neutral molecules tested may enter the erythrocytes via the same channel as amino acids, but do not interact with the sites blocked by Band 3 inhibitors, or through a separate channel of similar size which is also volume activated. © 1993 Wiley‐Liss, Inc.
Adeno‐associated virus‐mediated gene transfer of a secreted form of TRAIL inhibits tumor growth and occurrence in an experimental tumor model
Authors: Yoo Jinsang , Choi Seeyoung , Hwang Kyung‐Sun , Cho Won‐Kyung , Jung Cho‐Rok , Kwon Suk‐Tae , Im Dong‐Soo
Published: September 2005

Background

Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) induces cell death in various tumor cells, but relatively spares normal cells. Recombinant adeno‐associated virus (rAAV) vectors have a number of advantages including in vivo long‐term gene expression. Here, we assessed the biological activity of a novel, secreted form of TRAIL (sTRAIL) for cancer gene therapy using a rAAV2 vector.

Methods

A plasmid and rAAV2 vectors were constructed encoding sTRAIL composed of a leader sequence, the isoleucine zipper, and the active domain of TRAIL (aa 95–281). The functionality of sTRAIL was validated by cell viability, FACS analysis, caspase‐3 activity, and TUNEL staining. rAAV‐sTRAIL was injected intratumorally to nude mice bearing human A549 lung tumor cells. Nude mice received A549 tumor cells after intravenous delivery of rAAV‐sTRAIL. The antitumor effect was then evaluated by measuring tumor regression and occurrence in the experimental animal.

Results

sTRAIL was released from cells transfected with the sTRAIL expression construct or transduced with rAAV‐sTRAIL, and induced apoptosis in cancer cells, but spared normal fibroblast cells. Secreted sTRAIL formed oligomers including trimers with intersubunit disulfide. Purified sTRAIL exerted much lower cytotoxicity on primary human hepatocytes compared to recombinant TRAIL. Intratumoral delivery of rAAV‐sTRAIL significantly inhibited growth of A549 tumors established in nude mice. A number of apoptotic tumor cells were detected by TUNEL staining in mice treated with rAAV‐sTRAIL. Systemic pretreatment with rAAV‐sTRAIL significantly inhibited tumor formation in nude mice.

Conclusion

The results suggest that rAAV‐sTRAIL may be useful for local or systemic cancer gene therapy for treating TRAIL‐sensitive tumors. Copyright © 2005 John Wiley & Sons, Ltd.
Dynamic susceptibility contrast perfusion imaging of cerebral ischemia in nonhuman primates: Comparison of Gd‐DTPA and NMS60
Authors: Liu Yutong , D'Arceuil Helen , He Julian , Duggan Mike , Seri S. , Hashiguchi Yuji , Nakatani Akira , Gonzalez R. Gilberto , Pryor Johnny , de Crespigny Alex
Published: September 2005

Purpose

To study a new gadolinium (Gd) contrast agent—NMS60—for MR perfusion‐weighted imaging (PWI) of brain tissue.

Materials and Methods

NMS60 is a Gd3+ trimer with a molecular weight of 2158 Daltons, and a T2 relaxivity almost three times higher than that of Gd‐DTPA. Middle cerebral artery (MCA) occlusion was induced in nine nonhuman primates. The animals were scanned acutely and for up to six follow‐up time points. PWI peak, and time‐to‐peak maps were generated, and perfusion deficit volumes were measured from these maps. The values of peak, time‐to‐peak, and perfusion deficit volume were compared between NMS60 and GD‐DTPA.

Results

These results demonstrate that there was no significant difference in our calculated perfusion parameters between the two contrast agents.

Conclusion

The two agents were found to be equally effective for PWI for acute and chronic stroke in primates. Along with its previously demonstrated advantage for T1‐enhanced imaging, the current results show that NMS60 is a viable contrast agent for use in stroke patients. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Contrast‐enhanced MRI of ductal carcinoma in situ: Characteristics of a new intensity‐modulated parametric mapping technique correlated with histopathologic findings
Authors: Mariano Michelle N. , van den Bosch Maurice A.A.J. , Daniel Bruce L. , Nowels Kent W. , Birdwell Robyn L. , Fong Kathy J. , Desmond Pam S. , Plevritis Sylvia , Stables Lara A. , Zakhour Marowan , Herfkens Robert J. , Ikeda Debra M.
Published: September 2005

Purpose

To identify morphologic and dynamic enhancement magnetic resonance imaging (MRI) features of pure ductal carcinoma in situ (DCIS) by using a new intensity‐modulated parametric mapping technique, and to correlate the MRI features with histopathologic findings.

Materials and Methods

Fourteen patients with pure DCIS on pathology underwent conventional mammography and contrast‐enhanced (CE) MRI using the intensity‐modulated parametric mapping technique. The MR images were reviewed and the lesions were categorized according to morphologic and kinetic criteria from the ACR BI‐RADS‐MRI Lexicon, with BI‐RADS 4 and 5 lesions classified as suspicious.

Results

With the use of a kinetic curve shape analysis, MRI classified seven of 14 lesions (50%) as suspicious, including four with initial‐rapid/late‐washout and three with initial‐rapid/late‐plateau. Using morphologic criteria, MRI classified 10/14 (71%) as suspicious, with the most prominent morphologic feature being a regional enhancement pattern. Using the intensity modulated parametric mapping technique, MRI classified 12/14 cases (86%) as suspicious. Parametric mapping identified all intermediate‐ and high‐grade DCIS lesions.

Conclusion

The intensity‐modulated parametric mapping technique for breast MRI resulted in the highest detectionrate for the DCIS cases. Furthermore, the parametric mapping technique identified all intermediate‐ and high‐grade DCIS lesions, suggesting that a negative MRI using the parametric mapping technique may exclude intermediate‐ and high‐grade DCIS. This finding has potential clinical implications. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Split treatment of photodamaged skin with KTP 532 nm laser with 10 mm handpiece versus IPL: A cheek‐to‐cheek comparison
Authors: Butler E. George , McClellan Scott D. , Ross E. Victor
Published: September 2005

Background and Objectives

The treatment of photodamaged skin with potassium‐titanyl‐phosphate (KTP) laser and intense pulsed light (IPL) has been reported in several studies. Each device has strengths and weaknesses; however, patient and device variability have made it difficult to ascertain the optimal device for photorejuvenation. The objective of this study was to obtain a head‐to‐head comparison of IPL and KTP laser for photorejuvenation. Each patient received one KTP laser treatment on one side of the face and one IPL treatment on the other side.

Study Design/Materials and Methods

Seventeen patients with skin types I–IV were accepted into the study based on existence of dyschromias (pigmented and vascular) and/or discrete telangiectases. After performance of test spots on each patient to determine optimal settings for both devices, patients were treated with both devices in a split face manner. Evaluations and photographs were performed 1 week and 1 month after treatment. Patient and observer evaluations of results were recorded, as well as time to perform each treatment, and patient feedback with regard to pain and edema. No anesthesia was used in these treatments. Photographs were reviewed by a panel of blinded observers to assess changes in red and brown dyschromias.

Results

One month average improvement (evaluator) for IPL side was (mean) 38.16%/35.08% for vascular/pigment lesions versus 41.99%/30.21% for KTP side. Patient self‐evaluated global improvement at 1 month was (mean) 65.59% for IPL side versus 60.88% for KTP side. A majority of patients found the KTP to be slightly more painful with a mean pain rating of 5.27 of 10 versus 4.4 of 10 for IPL. A majority of patients experienced subjectively greater post‐procedure swelling on the KTP side. Time to conduct treatment was an average of 10.0 minutes for IPL, 8.7 minutes for KTP.

Conclusions

Both large spot KTP and IPL achieved marked improvement in vascular and pigmented lesions in one session. The KTP laser caused slightly more discomfort and edema than the IPL. On the other hand, the KTP laser was faster, and more ergonomically flexible. Lasers Surg. Med. 38:124–128, 2006. © 2005 Wiley‐Liss, Inc.
Spectral problems for operator matrices
Authors: Bátkai A. , Binding P. , Dijksma A. , Hryniv R. , Langer H.
Published: September 2005

We study spectral properties of 2 × 2 block operator matrices whose entries are unbounded operators between Banach spaces and with domains consisting of vectors satisfying certain relations between their components. We investigate closability in the product space, essential spectra and generation of holomorphic semigroups. Application is given to several models governed by ordinary and partial differential equations, for example containing delays, floating singularities or eigenvalue dependent boundary conditions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Taylor coefficients of a pseudo‐exponential potential and the reflection coefficient of the corresponding canonical system
Authors: Gohberg I. , Kaashoek M. A. , Sakhnovich A. L.
Published: September 2005

We study the connections between the Taylor coefficients at zero of a pseudo‐exponential potential of a canonical system and the reflection coefficient of the system determined by this potential. This connection is expressed explicitly. The main result of this paper provides a characterization of a pseudo‐exponential potential in terms of its Taylor coefficients at zero. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prüfer angle asymptotics for Atkinson's semi‐definite Sturm–Liouville eigenvalue problem
Authors: Binding Paul , Volkmer Hans
Published: September 2005

Atkinson's semi‐definite Sturm–Liouville problem consists of the differential equation –(y ′/s )′ + qy = λry , with s , q , r integrable on [a , b ], q real‐valued, s, r ≥ 0, and separated boundary conditions at a, b . The asymptotic behavior of the associated Prüfer angle is determined as λ → ±∞. This leads to existence theorems for eigenvalues λn with prescribed oscillation number n and their asymptotics. In general, λn grows faster than n 2, and the order of the corresponding characteristic function is less than ½. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some disconjugacy criteria for differential equations with oscillatory coefficients
Authors: Clark Stephen , Hinton Don
Published: September 2005

We determine conditions on the coefficients of both second and fourth order differential operators which give disconjugacy. The conditions exploit the change of sign of the coefficients to show how the change of sign enhances disconjugacy. An application is given to the stability of solutions of equations with periodic coefficients. Focal point and other boundary conditions are considered as well, and sufficient conditions are given which imply the nonexistence of nontrivial solutions of the differential equations satisfying the boundary conditions. Some open problems are stated for the minimization of certain nonlinear functionals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elliptic equations and products of positive definite matrices
Authors: Conley Charles H. , Pucci Patrizia , Serrin James
Published: September 2005

We present necessary and sufficient conditions under which the symmetrized product of two n ×n positive definite Hermitian matrices is still a positive definite matrix (Part I, Sections 2 and 3). These results are then applied to prove the validity of the strong maximum principle, as well as of the compact support principle, for nonnegative C 1 distribution solutions of general quasilinear inequalities, possibly not elliptic at points where the gradient variable is either zero or large (Part III, Sections 9 and 10).

In Part II (Sections 4–8) we consider the general problem of finding bounds for the least and greatest eigenvalues of the product of two (not necessarily definite) Hermitian matrices. In particular, we refine earlier results of Strang for this problem. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simple proofs of various fixed point and existence theorems based on exterior calculus
Authors: Mawhin J.
Published: September 2005

Using an unpublished result of Tartar about some integrals depending upon a parameter, we give quite elementary proofs of various fixed point theorems and of the fundamental theorems of algebra for complex numbers and quaternions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Forced oscillation of second order superlinear differential equations
Authors: Gong Sun Yuan , Wong James S. W.
Published: September 2005

In this paper, we establish some new criteria for the oscillation of second order forced nonlinear differential equations (r (t )x ′(t ))′ + p (t )x ′(t ) + q (t )f (x (t )) = e (t ) in both cases when q (t ) < 0 and q (t ) changes its sign. Our results are sharper than those of Agarwal and Grace [1], Cakmak and Tiryaki [2], Ou and Wong [17] for the second order case. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Poly(ethylene glycol) Surface Coated Magnetic Particles
Authors: Flesch Christophe , Unterfinger Yves , Bourgeat‐Lami Elodie , Duguet Etienne , Delaite Christelle , Dumas Philippe
Published: September 2005

Summary: A methacrylate‐functionalized poly(ethylene glycol) macromonomer was copolymerized at the surface of methacrylate‐derivatized maghemite nanoparticles. After silylation of the magnetic core with methacryloxypropyltrimethoxysilane, two grafting procedures based on either a direct copolymerization reaction in water or an inverse emulsion polymerization were compared. A direct copolymerization led to low polymer surface amounts, whereas an inverse emulsion process allowed nanocomposite particles containing up to 90 wt.‐% polymer to be obtained.

TEM picture of maghemite‐PEG hybrid particles.

magnified image

TEM picture of maghemite‐PEG hybrid particles.
Residual Stresses in Amorphous Polymers
Authors: Grassia Luigi , D'Amore Alberto
Published: September 2005

The origin of internal stresses in a polymeric component, subjected to an arbitrary cooling, will be described. The differential volume relaxation arising as a result of the different thermal history suffered by each body point was considered as the primary source of stresses build up. A numerical routine was developed accounting for the simultaneous stress relaxation processes and implemented within an Ansys® environment. The volume relaxation kinetics was modelled by using the four‐parameter TNM (Tool‐Narayanaswamy‐Mohynian) phenomenological theory using the PVT (Pressure–Volume‐Temperature) data obtained on a polystyrene sample. The numerical algorithm translates the specific volume theoretical predictions at each body point as applied non‐mechanical loads acting on the component. Thermorheological complexity emerged due to coupling of volume and stress relaxation phenomena A linear dependence of Poisson's ratio on the tensile relaxation modulus was postulated. A quantitative predictions of time dependent stress distribution was realized for two specific test cases.
Extension‐Enhanced Conductivity of Liquid Crystalline Polymer Nano‐Composites
Authors: Zhou Hong , Forest M. Gregory , Zheng Xiaoyu , Wang Qi , Lipton Robert
Published: September 2005

Our aim here is to predict elongational flow‐induced enhancements in thermal or electrical conductivity of liquid crystal polymer (LCP) nano‐composites. To do so, we combine two classical mathematical asymptotic analyses: slender longwave hydro‐thermo‐dynamics for fibers and exact analysis of pure elongation of LCPs in solvents for bulk phases without boundary effects; and homogenization theory for effective properties of low volume‐fraction spheroidal inclusions. Two implications follow: elongational flow dominates fiber free surface and thermal effects on electrical and thermal conductivity enhancements; and, there appears to be no sacrifice in enhancements by producing much higher radius, bulk fibers.
Effect of the Organoclay Structure on Morphology and Rheological Response of PBT Nanocomposites
Authors: Scarfato P. , Scatteia L. , Costa G. , Acierno D.
Published: September 2005

In this paper the effect of different organoclays on the structure and the rheological properties of poly(butyleneterephtalate)–clay nanocomposites produced by melt compounding was investigated. The study was carried out using as nanometric fillers four commercial montmorillonites, treated with different organic modifiers and having similar interlayer spacing and organo‐modifier concentration. Each organoclay was melt compounded with PBT (at 3%, 6% and 9% by weight of clay) using a twin screw extruder. Using the same processing conditions, hybrid samples containing the unmodified silicate were also prepared for comparison purposes. All the obtained nanocomposite samples were submitted to physico‐chemical (XRD, TEM and FT‐IR), and rheological measurements in order to evidence the role of polymer‐clay affinity on the morphology and on the viscoelastic response of the materials. The results have pointed out that, with the used processing conditions, all nanocomposites exhibit a mixed intercalated/exfoliated structure; nevertheless, the clay dispersion homogeneity and the exfoliation level reached in the samples are higher for Nanofil 919 and Dellite 43B fillers, the organic modifiers of which may favorably interact with PBT matrix.
Fabrication and Characterization of Sensitive Polymer (Nano)Composites
Authors: Loffredo Fausta , Quercia Luigi , Massera Ettore , Di Francia Girolamo
Published: September 2005

We report on the fabrication process of a polymer sensing device based on a thin film composite obtained by spinning or casting a carbon fillers/thermoplastic polymer dispersion on a glass substrates. In this work we produce thin composite films characterized by different grade of dispersion of carbon black in polymer matrix (Poly(methyl‐methacrylate), Poly(2 hydroxy‐ethyl‐methacrylate) and atactic poly(styrene)). We discuss, in particular the effect of the polymer and filler characteristics on the thin film morphology. Device material response towards different analytes will be also discussed. Size distribution of filler in polymer suspension and deposition method type strongly influence homogeneity and conductivity of corresponding polymer composite films and finally their sensor properties.
Practical and Theoretic Analysis of Resin Flow in Vacuum Assisted Resin Transfer Molding Processes
Authors: Tuccillo F. , Antonucci V. , Calabrò A.M. , Giordano M. , Nicolais L.
Published: September 2005

In this study, the non‐isothermal resin infiltration during the VARTM process has been analyzed and characterized.

In particular, the resin flow through the fibers has been described by the Darcy law and introducing the degree of saturation, the percent of void effectively occupied by the resin within a control volume, as variable in order to account for the moving boundary nature of the problem.

Some preliminary tests to measure the advancement of a reference substance, pure water, between the reinforcement fibers with embedded optic fibers sensors, show the capability of a new sensorial technology, based on use of non intrusive fiber optic COTS components, assembled into an original way. These sensors will be used for real time monitoring of the resin flow during the experimental infusion tests and for in‐situ demonstration of the capability and the reliability of the model, in the aim to assure a “process repeatability”.

Due the effectiveness lack of repeatability of VARTM, the Authors propose an approach to extract a parameter during the process, meaning a “Deviation” of modelized output (MOD Modelized Output Deviation). This parameter, obtained by use of optic fibers technology, may improve the standard quality of the production, analyzing and correcting with feed‐back capability the efficiency of the moulded manufactured devices.
Non‐Conventional Curing of Organic‐Inorganic Hybrids
Authors: Leonelli Cristina , Messori Massimo , Pilati Francesco , Veronesi Paolo
Published: September 2005

Infrared and microwave curing of organic–inorganic hybrid materials was studied, in order to achieve the maximum conversion without detrimental effects due to the overheating or to the long‐time permanence at high temperature.

Partially cured poly(ethylene oxide)/silica hybrids were prepared by hydrolysis and subsequent condensation of precursors for 30 minutes isothermal heat treatment at 70°C. The conversion after the preliminary treatment is still low and requires an additional heating to complete the reaction. Three different thermal treatments were investigated: conventional heating, infrared heating and microwave heating.

DSC characterisation of the obtained samples evidenced a drastic reduction of the treatment time when microwaves were used, requiring only a few seconds, compared to the hours‐lasting conventional treatments.
Fracture Behaviour and Deformation Mechanisms of Polyimide/Silica Hybrids
Authors: Ragosta Giuseppe , Musto Pellegrino , Abbate Mario , Russo Pietro , Scarinzi Gennaro
Published: September 2005

Films of particulate polyimide‐silica hybrids were produced by a sol‐gel process and were examined in terms of morphological structure and fracture properties at different temperatures, varying from 20 to 250 °C.

The fracture toughness characteristics were studied by the “Essential Work of Fracture” method using double edge‐notched specimens of different ligament lengths. The results showed that the fracture toughness, expressed through the essential (we) and non‐essential work of fracture (βwp) parameters increased when submicron silica particles were dispersed in the polyimide matrix. In particular, it was found that both we and βwp increased with temperature to a larger extent than the parent polyimide. This enhancement in the fracture toughness was attributed to extensive cavitations and shear yielding originating at the particle interface and within the matrix.
Impact of cognitive task on the posture of elderly subjects with Alzheimer's disease compared to healthy elderly subjects
Authors: Manckoundia Patrick , Pfitzenmeyer Pierre , d'Athis Philippe , Dubost Véronique , Mourey France
Published: September 2005

The aims of this study were to analyze the effects of cognitive task on static posture in Alzheimer's disease (AD) and in healthy elderly (HE) subjects and to evaluate whether those effects were greater in AD subjects than in HE subjects. We performed a posturographic analysis on 13 subjects with mild AD (mean age, 79.7 ± 5.1 years, Mini‐Mental State Examination scores between 18 and 23) and on 17 HE subjects (mean age, 78.5 ± 4.4 years). After watching a video sequence, the subjects were asked to maintain a stable upright posture while standing on a force platform. Then, the postural sway was measured during the following two conditions: (1) quiet standing and (2) both standing and answering questions about the video sequence. We were interested in the center of pressure (CoP) area and path. For each group, the single task was compared to the dual task for the CoP area and path. We also compared the variability of both CoP area (variation of the CoP area between the single and the dual task) and path (variation of the CoP path between the single and the dual task) between the two groups. We showed that there was no significant difference between the single and the dual task in HE subjects concerning the CoP area and path, in contrast to the AD group, and that variability of both the CoP area and path were significantly greater in the AD subjects than in the HE subjects. This finding may contribute to the risk of falls in AD patients. © 2005 Movement Disorder Society
Undersampling k‐space using fast progressive 3D trajectories
Authors: Spiniak Juan , Guesalaga Andres , Mir Roberto , Guarini Marcelo , Irarrazaval Pablo
Published: September 2005

In 3D MRI, sampling k‐space with traditional trajectories can be excessively time‐consuming. Fast imaging trajectories are used in an attempt to efficiently cover the k‐space and reduce the scan time without significantly affecting the image quality. In many applications, further reductions in scan time can be achieved via undersampling of the k‐space; however, no clearly optimal method exists. In most 3D trajectories the k‐space is divided into regions that are sampled with shots that share a common geometry (e.g., spirals). A different approach is to design trajectories that gradually but uniformly cover the k‐space. In the current work, successive shots progressively add sampled regions to the 3D frequency space. By cutting the sequence short, a natural undersampled method is obtained. This can be particularly efficient because in these types of trajectories the contribution of new information by later shots is less significant. In this work the performance of progressive trajectories for different degrees of undersampling is assessed with trajectories based on missile guidance (MG) ideas. The results show that the approach can be efficient in terms of reducing the scan time, and performs better than the stack of spirals (SOS) technique, particularly under nonideal conditions. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Quantitation and localization of blood‐to‐brain influx by magnetic resonance imaging and quantitative autoradiography in a model of transient focal ischemia
Authors: Knight Robert A. , Nagaraja Tavarekere N. , Ewing James R. , Nagesh Vijaya , Whitton Polly A. , Bershad Eric , Fagan Susan C. , Fenstermacher Joseph D.
Published: September 2005

The ability of gadolinium‐diethylenetriaminepentaacetic acid (Gd‐DTPA) enhanced MRI to localize and quantitate blood–brain barrier (BBB) opening was evaluated against quantitative autoradiographic (QAR) imaging of 14C‐α‐aminoisobutyric acid (AIB) distribution. The blood‐to‐brain transfer constant (Ki) for Gd‐DTPA was determined by MRI in rats after 3 h of focal cerebral ischemia plus 2.5 h of reperfusion (n = 9), and that of AIB was determined by QAR shortly thereafter. Tissue regions of interest (ROIs) for Gd‐DTPA leakage were identified by ISODATA segmentation of pre‐ and post‐Gd‐DTPA Look–Locker (L‐L) T1 maps. Patlak plots were constructed using time course of blood and tissue T1 changes induced by Gd for estimating Ki. Among the nine rats, 14 sizable regions of AIB uptake were found; 13 were also identified by ISODATA segmentation. Although the 13 MRI‐ROIs spatially approximated those of AIB uptake, the segmentation sometimes missed small areas of lesser AIB uptake that did not extend through more than 60% of the 2.0‐mm‐thick slice. Mean Ki's of AIB were highly correlated with those of Gd‐DTPA across the 13 regions; the group means (±SD) were similar for the two tracers (7.1 ± 3.3 × 10−3 and 6.8 ± 3.5 × 10−3 ml.g−1 · min−1, respectively). In most instances, Gd‐DTPA MRI accurately localized areas of BBB opening. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Low density polyethylene and grafted lignin polyblends using epoxy‐functionalized compatibilizer: mechanical and thermal properties
Authors: Sailaja RRN
Published: September 2005

Lignin was graft copolymerized with methyl methacrylate using manganic pyrophosphate as initiator. This modified lignin was then blended (up to 50 wt%) with low density polyethylene (LDPE) using a small quantity of poly[ethylene‐co‐(glycidyl methacrylate)] (PEGMA) compatibilizer. The mechanical properties of the blend were substantially improved by using modified lignin in contrast to untreated lignin. Differential scanning calorimetry studies showed loss of crystallinity of the LDPE phase owing to the interaction between the blend components. Thermogravimetric analysis showed higher thermal stability of modified lignin in the domain of blend processing. This suggested that there is scope for useful utilization of lignin, which could also lead to the development of eco‐friendly products. Copyright © 2005 Society of Chemical Industry