bluuebunny/crossref_metadata_2025 huggingface dataset:
Open comedones overlying granuloma annulare in a photoexposed area
Authors: Sudy Emilio , Urbina Francisco , Espinoza Ximena
Published: August 2006

A 57‐year‐old, fair‐skinned female patient with lesions of granuloma annulare located on her forearms – with signs of actinic damage – is described. No response was observed after successive treatments with topical corticosteroids and oral pentoxifylline. Four years later, the patient developed open comedones on the rim of granuloma annulare lesions. The loss of elastic fibers seen in both granuloma annulare and solar elastosis is presumed to have induced the appearance of open comedones, because of a loss of supporting properties of the dermis inducing a distension of the infundibular canal of the sebaceous follicle, as seen in the Favre–Racouchot disease and actinic comedonal plaque. Concomitantly, the patient developed insulin‐dependent diabetes mellitus. Treatment with insulin resulted in the disappearance of open comedones and notably regression of lesions of granuloma annulare. Response to insulin therapy in our case supports the hypothesis that insulinopenia could participate in the development of granuloma annulare in some cases.
Evidence for a bystander role of neutrophils in the response to systemic 5‐aminolevulinic acid‐based photodynamic therapy
Authors: De Bruijn Henriëtte S. , Sluiter Wim , Van Der Ploeg‐van den Heuvel Angélique , Sterenborg Henricus J. C. M. , Robinson Dominic J.
Published: August 2006

Background/purpose: A significant increase in the number of circulating and tumour neutrophils immediately after therapy was observed while investigating the increase in response of tissues to aminolevulinic acid‐based photodynamic therapy (ALA‐PDT) using a twofold illumination scheme with a prolonged dark interval. The action of (tumour) neutrophils is an important therapeutic adjunct to the deposition of singlet oxygen within the treatment volume, for many photosensitizers. It is not known if those phagocytes contribute to the improved outcome of ALA‐PDT. In this study we investigated the role of neutrophils in the response to PDT using systemic ALA with and without light fractionation.

Methods: Rhabdomyosarcoma, transplanted in the thigh of female WAG/Rij rats were illuminated transdermally using 633 nm light following i.v. administration of 200 mg/kg ALA. The pharmacokinetics of protoporphyrin IX (PpIX) within the tumour tissue during therapy were determined to compare with that observed in other models for topical administration of ALA. PDT was performed under immunologically normal or neutropenic conditions using various illumination schemes. The number of neutrophils in tumour and in the circulation were determined as a function of time after treatment and compared with growth delay of each scheme.

Results: Fluorescence spectroscopy revealed similar pharmacokinetics of PpIX to those observed during and after topical ALA‐PDT. The number of neutrophils within the illuminated tumour and in the circulation increased significantly following therapy. This increase in the number of neutrophils was associated with an increase in the efficacy of therapy: the more effective the therapy the greater the increase in tumour and blood neutrophils. Administration of anti‐granulocyte serum treatment prevented the influx of neutrophils after ALA‐PDT, but did not lead to a significant decrease in the efficacy of the PDT treatment on the growth of the tumour for any illumination scheme investigated.

Conclusion: These results indicate that the magnitude of damage inflicted on the tumour by ALA‐PDT does not depend on the presence of neutrophils in the tumour or circulation and that the role of neutrophils in ALA‐PDT is much less important than in PDT using other photosensitizers. These data contribute to the understanding of the mechanism of response of tissue to systemic ALA‐PDT.
Clinicopathological analysis of osteosarcoma of jaw bones
Authors: Nissanka EH , Amaratunge EAPD , Tilakaratne WM
Published: August 2006

Objectives:  To identify clinicopathological characteristics and prognosis of osteosarcoma of the jaw bones (JOS) and to compare the data with results of similar studies. To study the effectiveness of different treatment modalities currently available for this malignancy.

Subjects and methods:  Nineteen cases of JOS diagnosed from 1993 to 2003 were retrieved from the departmental archives. These were categorized into histopathological subtypes and graded according to the severity of the malignancies and the data analyzed. Fourteen cases were followed up and the success rate with different treatment modalities assessed.

Results:  The mean age for JOS was 34.1 years. There were 11 mandibular lesions and eight maxillary lesions. Osteoblastic variant (53%) was the commonest histopathological subtype. High grade (grades III and IV) was more prevalent. All 14 followed up patients underwent surgical excision – five with adjuvant radiotherapy and six with adjuvant chemotherapy. Local recurrence was the commonest complication. Nine of the 14 were surviving with a survival rate of 64.2% for a median follow‐up period of 5.25 years.

Conclusions:  JOS is a distinct group of lesions with a better prognosis if diagnosed and treated early. It does not show any ethnic variability. Existing histopathological typing and grading may not indicate the prognosis of JOS. Adjuvant chemotherapy is a better treatment modality than adjuvant radiotherapy.
Histomorphometry and immunohistochemical features of grade I (WHO) oral radiomucositis
Authors: Bonan PRF , Kaminagakura E , Pires FR , Vargas PA , De Almeida OP
Published: August 2006

Aims:  The aims of this study were to describe the immunohistopathological and morphometric features of oral mucositis grade I (WHO).

Material and Methods:  Ten samples of oral mucositis were biopsied and submitted to histopathological, morphometric and immunohistochemical analyses (CD68, Ki‐67 and p53). The samples were compared with the buccal mucosa of head and neck cancer patients before radiotherapy (NMCP), normal buccal mucosa (NM) and oral dysplasia (OD).

Results:  Epithelial thickness, area and perimeter were decreased in oral mucositis and inflammatory components, increased when compared with NMCP. CD68 immunoreactivity, near to the epithelium, was more evident in oral mucositis than in NMCP (P = 0.01). The Ki‐67 counts were higher in oral mucositis than in NM and NMCP (P = 0.001 and P = 0.043, respectively), but without any difference with OD (P = 0.284). The p53 staining was present in all cases of mucositis and oral dysplasia, but negative in NMCP and NM.

Conclusions:  Oral mucositis grade I (WHO) presented epithelial atypia and atrophy, increased inflammatory response, with relevant Ki‐67 count and positiveness for p53.
Subcutaneous administration of lactone form of simvastatin stimulates ectopic osteoinduction by rhBMP‐2
Authors: Sugiyama T , Nakagawa T , Sato C , Fujii T , Mine K , Shimizu K , Murata T , Tagawa T
Published: August 2006

Objective:  To evaluate the effects of various 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase inhibitors (statins) on ectopic osteoinduction by recombinant human bone morphogenetic protein‐2 (rhBMP‐2) using different administration methods.

Materials and methods:  Disks containing 5 μg of rhBMP‐2 and type I collagen were implanted into the calf muscles of 6‐week‐old male rats (n = 64). Either the lactone form of simvastatin (SV), open hydroxy‐acid form of simvastatin (SVA), cerivastatin (CVA), or vehicle (control) was then administered per orally (PO group) or subcutaneously (SC group) for 20 days. The disks were removed on day 21 after implantation, and ectopic induced bone formation was evaluated by radiographic, histologic, and biochemical analysis.

Results:  Both the projected and radiopaque area on X‐ray film, and the calcium content of the SV group in the SC group (SV–SC group) were significantly greater than those in the other SC and PO groups. Alkaline phosphatase activity and tartrate‐resistant acid phosphatase activity in the SV–SC group were significantly lower than those in the other SC and PO groups. Histologic examination revealed an increase of ectopic induced bone volume in the SV–SC group.

Conclusion:  Subcutaneous administration of SV stimulates ectopic osteoinduction by rhBMP‐2 through reduction of bone turnover.
Stimulated whole salivary flow rate and composition in menopausal women with oral dryness feeling
Authors: Agha‐Hosseini F , Mirzaii‐Dizgah I , Moghaddam PP , Akrad ZT
Published: August 2006

The aim of this study was to compare stimulated whole saliva flow rate and composition of menopausal women with/without oral dryness (OD) feeling. A case–control study was carried out in 42 selected menopausal women aged 52–73 years with or without OD feeling (21 as case and 21 as control) conducted at the Clinic of Oral Medicine, Tehran University of Medical Sciences. Paraffin‐stimulated saliva samples were obtained by expectoration. The stimulated whole saliva composition was measured by a spectrophotometer [magnesium (Mg+2), calcium (Ca+2), chloride (Cl−), inorganic phosphate (Pi) and total protein], flame‐photometry [sodium (Na+)] and ion selective electrode (ISE) [potassium (K+)] methods. No significant differences were found in stimulated whole saliva flow rate, Mg+2, Cl−, Pi, Na+, K+ and total protein concentrations between the two groups, but the mean calcium concentration was significantly higher in cases than in controls (P = 0.003). It seems that the level of salivary calcium concentration may be higher in menopausal women with OD feeling than in the control group.
Cochlear implantation in children: Implications for the primary care provider
Authors: Goller Yael
Published: August 2006

Purpose: To define hearing loss (HL), discuss the impact of HL on child development, and review the literature on cochlear implantation in children. The criteria for and the benefits and limitations of cochlear implantation in children, as well as the implications for the primary care provider with regard to children who have cochlear implants, are presented.

Data sources: Review of published literature on the topic.

Conclusions: A child’s future development depends greatly on speech and language skills. Any type of HL can impact and may even hinder speech and language acquisition. It is therefore crucial to enforce early identification of HL. For severe to profoundly hearing‐impaired children, cochlear implantation serves as an avenue for hearing and language development.

Implications for practice: Nurse practitioners ought to be up to date with criteria for and the benefits and risks of cochlear implantation. Health‐related issues, such as vaccination, otitis media, and meningitis, must be assessed for and managed promptly.
Multiple limbal haemangiosarcomas in a border collie dog: management by lamellar keratectomy/sclerectomy and strontium‐90 beta plesiotherapy
Authors: Donaldson D. , Sansom J. , Murphy S. , Scase T.
Published: August 2006

An eight‐year‐old, neutered, male border collie dog was presented with a six‐week history of left ocular discomfort and a raised, red mass at the lateral limbus. The right eye had been enucleated approximately 12 months previously following suspected trauma when the eye had become red and painful. The mass was excised using superficial keratectomy/sclerectomy and the surgery site was treated with strontium‐90 beta radiation. Histopathological findings were consistent with a diagnosis of haemangiosarcoma. Immunohistochemical staining showed uniform expression of CD31 in neoplastic cells, confirming their endothelial origin. Two further treatments with strontium‐90 beta radiation were applied to the surgical site at weekly intervals. Twenty‐six weeks after surgery, a second, raised, red limbal mass became apparent at the medial limbus of the left eye. Surgical excision and adjuvant strontium‐90 beta plesiotherapy were performed as described for the initial tumour. Routine histopathological analysis confirmed haemangiosarcoma at this site. Eighty‐six weeks following the initial presentation, no recurrence of ocular haemangiosarcoma was evident.
Surgical resection of a primary tracheal fibrosarcoma in a dog
Authors: Mahler S. P. , Mootoo N. F. A. , Reece J. L. M. , Cooper J. E.
Published: August 2006

A four‐year‐old, entire male Rottweiler was presented with a history of respiratory distress. A tracheal mass was diagnosed on thoracic radiographs and tracheoscopy. Surgical excision of three tracheal rings incorporating the tumour was performed. The mass was found to be a low‐grade fibrosarcoma. Twenty‐four months later, the owner reported that there was no recurrence of respiratory distress and the dog appeared to be doing well clinically. This case of primary tracheal fibrosarcoma suggests that this type of tumour should be listed in the differential diagnoses for tracheal neoplasia in dogs and that surgical treatment alone may be curative.
Clinical approach to renal neoplasia in budgerigars (Melopsittacus undulatus)
Authors: Simova‐Curd S. , Nitzl D. , Mayer J. , Hatt J.‐M.
Published: August 2006

Renal neoplasia in budgerigars (Melopsittacus undulatus) is seen regularly in general practice and is of interest to many practicing veterinary surgeons. This review article provides an overview of the current knowledge and the most recent reports in avian literature regarding renal tumours in budgerigars, with the emphasis on clinical diagnosis and treatment. The high prevalence of renal neoplasia in budgerigar is discussed, with notes on the most commonly diagnosed tumours, possibility of metastases, sex and age predisposition. The possibility of ultrasonography and radiography in the diagnosis of this pathological condition are compared as well as the possible role of blood and urine analyses. Two studies are described, both of which investigate the possible involvement of a retrovirus as the aetiological agent.
Human LineageSpecific Amplification, Selection, and Neuronal Expression of DUF1220 Domains
Authors: Popesco Magdalena C. , MacLaren Erik J. , Hopkins Janet , Dumas Laura , Cox Michael , Meltesen Lynne , McGavran Loris , Wyckoff Gerald J. , Sikela James M.
Published: August 2006

Extreme gene duplication is a major source of evolutionary novelty. A genome-wide survey of gene copy number variation among human and great ape lineages revealed that the most striking human lineage–specific amplification was due to an unknown gene,
MGC8902
, which is predicted to encode multiple copies of a protein domain of unknown function (DUF1220). Sequences encoding these domains are virtually all primate-specific, show signs of positive selection, and are increasingly amplified generally as a function of a species' evolutionary proximity to humans, where the greatest number of copies (212) is found. DUF1220 domains are highly expressed in brain regions associated with higher cognitive function, and in brain show neuron-specific expression preferentially in cell bodies and dendrites.
A Role for the Macaque Anterior Cingulate Gyrus in Social Valuation
Authors: Rudebeck P. H. , Buckley M. J. , Walton M. E. , Rushworth M. F. S.
Published: August 2006

Complex human social interaction is disrupted when the frontal lobe is damaged in disease, and in extreme cases patients are described as having acquired sociopathy. We compared, in macaques, the effects of lesions in subdivisions of the anterior cingulate and the orbitofrontal cortices believed to be anatomically homologous to those damaged in such patients. We show that the anterior cingulate gyrus in male macaques is critical for normal patterns of social interest in other individual male or female macaques. Conversely, the orbitofrontal cortex lesion had a marked effect only on responses to mildly fear-inducing stimuli. These results suggest that damage to the anterior cingulate gyrus may be the cause of changes in social interaction seen after frontal lobe damage.
50-Ma Initiation of Hawaiian-Emperor Bend Records Major Change in Pacific Plate Motion
Authors: Sharp Warren D. , Clague David A.
Published: August 2006

The Hawaiian-Emperor bend has played a prominent yet controversial role in deciphering past Pacific plate motions and the tempo of plate motion change. New ages for volcanoes of the central and southern Emperor chain define large changes in volcanic migration rate with little associated change in the chain's trend, which suggests that the bend did not form by slowing of the Hawaiian hot spot. Initiation of the bend near Kimmei seamount about 50 million years ago (MA) was coincident with realignment of Pacific spreading centers and early magmatism in western Pacific arcs, consistent with formation of the bend by changed Pacific plate motion.
Fluorous Nanodroplets Structurally Confined in an Organopalladium Sphere
Authors: Sato Sota , Iida Junya , Suzuki Kosuke , Kawano Masaki , Ozeki Tomoji , Fujita Makoto
Published: August 2006

The distinct properties of fluorous phases are practically useful for separation, purification, and reaction control in organic synthesis. Here, we report the formation of a liquid-like fluorous droplet, composed of 24 perfluoroalkyl chains confined in the interior of a 5-nanometer-sized, roughly spherical shell that spontaneously assembled in solution from 12 palladium ions and 24 bridging ligands. Crystallographic analysis confirmed the rigid shell framework and amorphous interior. Perfluoroalkanes can dissolve in this well-defined fluorous phase, whereas they can hardly dissolve in a surrounding polar organic solution, and their solubility (up to ∼eight perfluoroalkane molecules per spherical complex) can be finely controlled by tuning the length of perfluoroalkyl chains tethered to the shell.
Exploiting the Reversibility of Natural Product Glycosyltransferase-Catalyzed Reactions
Authors: Zhang Changsheng , Griffith Byron R. , Fu Qiang , Albermann Christoph , Fu Xun , Lee In-Kyoung , Li Lingjun , Thorson Jon S.
Published: August 2006

Glycosyltransferases (GTs), an essential class of ubiquitous enzymes, are generally perceived as unidirectional catalysts. In contrast, we report that four glycosyltransferases from two distinct natural product biosynthetic pathways—calicheamicin and vancomycin—readily catalyze reversible reactions, allowing sugars and aglycons to be exchanged with ease. As proof of the broader applicability of these new reactions, more than 70 differentially glycosylated calicheamicin and vancomycin variants are reported. This study suggests the reversibility of GT-catalyzed reactions may be general and useful for generating exotic nucleotide sugars, establishing in vitro GT activity in complex systems, and enhancing natural product diversity.
Chemically Induced Fast Solid-State Transitions of ω-VOPO
4
in Vanadium Phosphate Catalysts
Authors: Conte Marco , Budroni Gerolamo , Bartley Jonathan K. , Taylor Stuart H. , Carley Albert F. , Schmidt Andi , Murphy Damien M. , Girgsdies Frank , Ressler Thorsten , Schlögl Robert , Hutchings Graham J.
Published: August 2006

Vanadium phosphates are important catalysts for the oxidation of alkanes, and commercial catalysts comprise a complex range of V
4+
and V
5+
phosphates. We used three complementary in situ characterization methodologies—powder x-ray diffraction and laser Raman and electron paramagnetic resonance spectroscopies—to show that the metastable phase ω-VOPO
4
is very sensitive to many of the reactants and products of butane oxidation. A rapid transformation from ω-VOPO
4
to δ-VOPO
4
occurs on exposure to butane at the reaction temperature, and hence the metastable ω-VOPO
4
may play a role in the formation of commercial catalysts.
Response to Comment on "A Well-Preserved
Archaeopteryx
Specimen with Theropod Features"
Authors: Mayr Gerald , Peters D. Stefan
Published: August 2006

We agree that statistical support for our proposed phylogeny is weak, but the monophyly of Aves favored by most current researchers is also weakly supported. In the absence of unambiguous apomorphies of a clade including
Archaeopteryx
and
Confuciusornis
but not deinonychosaurs, we do not believe that the statistical comparisons made by Corfe and Butler challenge our hypothesis regarding the ancestry of birds.
DISSIPATIVE SOLITONS AND COMPLEX CURRENTS IN ACTIVE LATTICES
Authors: CHETVERIKOV A. P. , EBELING W. , VELARDE M. G.
Published: August 2006

We first summarize features of free, forced and stochastic harmonic oscillations and, following an idea first proposed by Lord Rayleigh in 1883, we discuss the possibility of maintaining them in the presence of dissipation. We describe how phonons appear in a harmonic (linear) lattice and then use the Toda exponential interaction to illustrate solitonic excitations (cnoidal waves) in a one-dimensional nonlinear lattice. We discuss properties such as specific heat (at constant length/volume) and the dynamic structure factor, both over a broad range of temperature values. By considering the interacting Toda particles to be Brownian units capable of pumping energy from a surrounding heat bath taken as a reservoir we show that solitons can be excited and sustained in the presence of dissipation. Thus the original Toda lattice is converted into an active lattice using Lord Rayleigh's method. Finally, by endowing the Toda–Brownian particles with electric charge (i.e. making them positive ions) and adding free electrons to the system we study the electric currents that arise. We show that, following instability of the base linear Ohm(Drude) conduction state, the active electric Toda lattice is able to maintain a form of high-T supercurrent, whose characteristics we then discuss.
COMPUTATIONAL STUDIES OF DISCRETE BREATHERS — FROM BASICS TO COMPETING LENGTH SCALES
Authors: FLACH SERGEJ , GORBACH ANDREY
Published: August 2006

This work provides a description of the main computational tools for the study of discrete breathers. It starts with the observation of breathers through simple numerical runs, the study uses targeted initial conditions, and discrete breather impact on transient processes and thermal equilibrium. We briefly describe a set of numerical methods to obtain breathers up to machine precision. In the final part of this work we apply the discussed methods to study the competing length scales for breathers with purely anharmonic interactions — favoring superexponential localization — and long range interactions, which favor algebraic decay in space. As a result, we observe and explain the presence of three different spatial tail characteristics of the considered localized excitations.
THE MATHEMATICS OF THE IMAGING TECHNIQUES OF MEG, CT, PET AND SPECT
Authors: FOKAS A. S. , MARINAKIS V.
Published: August 2006

The imaging techniques of magnetoencephalography (MEG), computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT) are reviewed, and the analytical solutions of the relevant inverse problems are presented. The numerical implementation of the exact formulas yield accurate reconstructions for both realistic phantoms as well as real data.
SELF-ORGANIZATION AND NONEQUILIBRIUM AGGREGATION PHENOMENA IN COLLOIDAL MATTER: WHY MICROGRAVITY MATTERS
Authors: BASIOS VASILEIOS
Published: August 2006

The relevance of self-organization, nonlinear phenomena and nonequilibrium behavior in a wide range of problems in space science and microgravity research, calls for a concerted approach using the tools of statistical physics, thermodynamics, nonlinear dynamics, mathematical modeling and numerical simulation, in synergy with experimentally oriented work.

The reason behind the ubiquity of such concepts is that in many instances of relevance in space science one witnesses an interplay between molecular and macroscopic-level entities and processes, such as nucleation in phase transitions or aggregation and self-assembly in materials science and biology. These phenomena are fundamentally dynamic in nature. We present two minimal models one dealing with issues of complex behavior at the microscopic level and the second referring to the strong nonlinear nature of macroscopic evolution, relevant to soft-condensed matter under observation both on the ground and in microgravity conditions.

These investigations open the way to a whole class of unexpected situations whose proper characterization and control can only be expected in the framework of nonequilibrium physics and complexity theory.
ON THE EXTENSIVITY OF THE ENTROPY SqFOR N ≤ 3 SPECIALLY CORRELATED BINARY SUBSYSTEMS
Authors: SATO YUZURU , TSALLIS CONSTANTINO
Published: August 2006

Many natural and artificial systems whose range of interaction is long enough are known to exhibit (quasi)stationary states that defy the standard, Boltzmann–Gibbs statistical mechanical prescriptions. For handling such anomalous systems (or at least some classes of them), nonextensive statistical mechanics has been proposed based on the entropy [Formula: see text], with [Formula: see text] (Boltzmann–Gibbs entropy). Special collective correlations can be mathematically constructed such that the strictly additive entropy is now Sqfor an adequate value of q ≠ 1, whereas Boltzmann–Gibbs entropy is nonadditive. Since important classes of systems exist for which the strict additivity of Boltzmann–Gibbs entropy is replaced by asymptotic additivity (i.e. extensivity), a variety of classes are expected to exist for which the strict additivity of Sq(q ≠ 1) is similarly replaced by asymptotic additivity (i.e. extensivity). All probabilistically well defined systems whose adequate entropy is S1are called extensive (or normal). They correspond to a number Weffof effectively occupied states which grows exponentially with the number N of elements (or subsystems). Those whose adequate entropy is Sq(q ≠ 1) are currently called nonextensive (or anomalous). They correspond to Weffgrowing like a power of N. To illustrate this scenario, recently addressed [Tsallis, 2004] we provide in this paper details about systems composed by N = 2, 3 two-state subsystems.
SOLITARY WAVE INTERACTIONS WITH CONTINUOUS WAVES
Authors: KOMINIS Y. , HIZANIDIS K.
Published: August 2006

Solitary wave propagation under interaction with continuous waves is studied in the context of the Nonlinear Schrödinger Equation. An analytical approach, based on the conserved quantities of the wave evolution, is used to study transverse velocity variations for the case of nonzero transverse wavenumber difference between the solitary and continuous waves. The method is applicable for any number of transverse dimensions and any kind of nonlinearity. Moreover, the presence of a coherent continuous background is shown to be responsible for the creation of solitary rings and spirals, under interaction with solitary structures with nonzero topological charge. Numerical simulations for specific cases were used to confirm the analytical results.
DYNAMICS OF TWO RESISTIVELY COUPLED DUFFING-TYPE ELECTRICAL OSCILLATORS
Authors: KYPRIANIDIS I. M. , VOLOS CH. , STOUBOULOS I. N. , HADJIDEMETRIOU J.
Published: August 2006

Duffing-type electrical oscillator is a second-order nonlinear electric circuit driven by a sinusoidal voltage source. The nonlinear element is a nonlinear inductor. We have studied the dynamics of two resistively coupled oscillators of this type in two cases. The first, when the oscillators are identical having chaotic dynamics, and the second, when the oscillators are in different dynamic states (periodic and chaotic, respectively). In the first case, chaotic synchronization is observed, while in the second case control of the chaotic behavior is achieved.
THE PLANAR PHOTOGRAVITATIONAL HILL PROBLEM
Authors: PAPADAKIS K. E.
Published: August 2006

In the planar photogravitational Hill problem (PHP) three equivalent forms of the equations of motion are presented: the physical equations of motion and two more forms of the regularized equations of the problem. Using the Levi–Civita coordinate transformation as well as the corresponding time transformation, we first obtain a simple regularized polynomial Hamiltonian of the dynamical system, and second the regularized equations of motion without using a regularized Hamiltonian. The relation between the physical and the regularized variables are also given. Zero velocity curves and surfaces, Poincaré sections, families of symmetric periodic orbits as well as their stability are given in physical and regularized variables when the larger primary body (the sun) does not radiate and when it does. It is found that for large deviations of its value from the gravitational case, the radiation factor can have a strong effect on the structure of the families. Finally we present the stability regions in both cases with and without radiation using the maximal Lyapunov exponent (LE), working in the regularized equations of motion of the problem since through these the calculation of the stability is more rapid and accurate than using the physical equations of motion.
A NONINTEGRABILITY CRITERION FOR ADIABATIC SYSTEMS
Authors: VOYATZI DESPINA , MELETLIDOU EFI
Published: August 2006

In the present paper we investigate the nonintegrability of adiabatic one degree of freedom Hamiltonian systems, with the additional assumption that the frozen system possesses an unstable fixed point with two asymmetric homoclinic loops. We prove a criterion for the nonexistence of an integral for such systems, and therefore we prove the nonexistence of a quantity which is conserved in an arbitrarily high order on ε. A specific application is given in the asymmetric quartic oscillator with adiabatic time dependence.
Software for simulating calcium-triggered exocytotic processes
Authors: Carrera Germán , Gil Amparo , Segura Javier , Soria Bernat
Published: August 2006

We describe a software package for the simulation of exocytotic events from readily releasable pools of secretory vesicles in neuroendocrine cells and presynaptic terminals. The visual package Ca3D_Exolab simulates the entry of Ca2+ through the calcium channels, the kinetic reactions of calcium with buffers, the diffusion of calcium and mobile buffers, and the kinetic reactions of calcium with the secretory vesicles. The location of both channels and secretory vesicles can be set by using a graphical interface. Calcium and buffer concentrations at different depths from the cellular membrane and capacitance time courses are obtained as outputs. The software package also provides a descriptive statistical data analysis of the different output data.
Selective labeling and isolation of functional classes of interstitial cells of Cajal of human and murine small intestine
Authors: Chen Hui , Redelman Doug , Ro Seungil , Ward Sean M. , Ördög Tamás , Sanders Kenton M.
Published: August 2006

Specific functions of interstitial cells of Cajal (ICC) have been linked to distinct classes that differ by morphology and distribution. In the small intestine, slow wave-generating ICC are located in the myenteric region (ICC-MY), whereas ICC that mediate neuromuscular neurotransmission occur either throughout the circular muscle layer (intramuscular ICC, ICC-IM) or in association with the deep muscular plexus (ICC-DMP). Selective isolation of ICC to characterize specific properties has been difficult. Recently, neurokinin-1 receptors have been detected in murine ICC-DMP and neurons but not in ICC-MY. Here we identified and isolated ICC-DMP/IM by receptor-mediated internalization of fluorescent substance P and Kit immunofluorescence. Specificity of labeling was verified by confocal microscopy. Mouse and human ICC-DMP/IM were detected in suspension by fluorescent microscopy and harvested for RT-PCR with micropipettes. The isolated cells expressed Kit but not markers for neurons, smooth muscle, or antigen-presenting cells. ICC-DMP expressed neurokinin-1 receptor, M2 and M3 muscarinic receptors, P2Y1 and P2Y4 purinergic receptors, VIP receptor 2, soluble guanylate cyclase-1 subunits, and protein kinase G. L- or T-type Ca2+ channels were not detected in these cells. ICC-MY and ICC-DMP were simultaneously detected and enumerated by flow cytometry and sorted to purity by fluorescence-activated cell sorting. In summary, functional classes of ICC have distinct molecular identities that can be used to selectively identify and harvest these cells with, for example, receptor-mediated uptake of substance P and Kit immunofluorescence. ICC-DMP express neurotransmitter receptors and signaling intermediate molecules that are consistent with their role in neuromuscular neurotransmission.
Mechanism of shortened action potential duration in Na+-Ca2+ exchanger knockout mice
Authors: Pott Christian , Ren Xiaoyan , Tran Diana X. , Yang Ming-Jim , Henderson Scott , Jordan Maria C. , Roos Kenneth P. , Garfinkel Alan , Philipson Kenneth D. , Goldhaber Joshua I.
Published: August 2006

In cardiac-specific Na+-Ca2+ exchanger (NCX) knockout (KO) mice, the ventricular action potential (AP) is shortened. The shortening of the AP, as well as a decrease of the L-type Ca2+ current ( ICa), provides a critical mechanism for the maintenance of Ca2+ homeostasis and contractility in the absence of NCX (Pott C, Philipson KD, Goldhaber JI. Excitation-contraction coupling in Na+-Ca2+ exchanger knockout mice: reduced transsarcolemmal Ca2+ flux. Circ Res 97: 1288–1295, 2005). To investigate the mechanism that underlies the accelerated AP repolarization, we recorded the transient outward current ( Ito) in patch-clamped myocytes isolated from wild-type (WT) and NCX KO mice. Peak Ito was increased by 78% and decay kinetics were slowed in KO vs. WT. Consistent with increased Ito, ECGs from KO mice exhibited shortened QT intervals. Expression of the Ito-generating K+ channel subunit Kv4.2 and the K+ channel interacting protein was increased in KO. We used a computer model of the murine AP (Bondarenko VE, Szigeti GP, Bett GC, Kim SJ, and Rasmusson RL. Computer model of action potential of mouse ventricular myocytes. Am J Physiol Heart Circ Physiol 287: 1378–1403, 2004) to determine the relative contributions of increased Ito, reduced ICa, and reduced NCX current ( INCX) on the shape and kinetics of the AP. Reduction of ICa and elimination of INCX had relatively small effects on the duration of the AP in the computer model. In contrast, AP repolarization was substantially accelerated when Ito was increased in the computer model. Thus, the increase in Ito, and not the reduction of ICa or INCX, is likely to be the major mechanism of AP shortening in KO myocytes. The upregulation of Ito may comprise an important regulatory mechanism to limit Ca2+ influx via a reduction of AP duration, thus preventing Ca2+ overload in situations of reduced myocyte Ca2+ extrusion capacity.
Bcl-2 family members and apoptosis, taken to heart
Authors: Gustafsson Åsa B. , Gottlieb Roberta A.
Published: August 2006

Loss of myocardial cells via apoptosis has been observed in many cardiovascular diseases and has been shown to contribute to the initiation and progression of heart failure. The Bcl-2 family members are important regulators of the mitochondrial pathway of apoptosis. These proteins decide whether the mitochondria should initiate the cell death program and release proapoptotic factors such as cytochrome c. The Bcl-2 proteins consist of anti- and proapoptotic members and play a key role in regulating apoptosis in the myocardium. The antiapoptotic proteins have been demonstrated to protect against various cardiac pathologies, whereas the antiapoptotic proteins have been reported to contribute to heart disease. This review summarizes the current understanding of the role of Bcl-2 proteins in the heart.
Mitochondrial function in vivo evaluated by NADH fluorescence: from animal models to human studies
Authors: Mayevsky Avraham , Rogatsky Gennady G.
Published: August 2006

Normal mitochondrial function is a critical factor in maintaining cellular homeostasis in various organs of the body. Due to the involvement of mitochondrial dysfunction in many pathological states, the real-time in vivo monitoring of the mitochondrial metabolic state is crucially important. This type of monitoring in animal models as well as in patients provides real-time data that can help interpret experimental results or optimize patient treatment. The goals of the present review are the following: 1) to provide an historical overview of NADH fluorescence monitoring and its physiological significance; 2) to present the solid scientific ground underlying NADH fluorescence measurements based on published materials; 3) to provide the reader with basic information on the methodologies used in the past and the current state of the art fluorometers; and 4) to clarify the various factors affecting monitored signals, including artifacts. The large numbers of publications by different groups testify to the valuable information gathered in various experimental conditions. The monitoring of NADH levels in the tissue provides the most important information on the metabolic state of the mitochondria in terms of energy production and intracellular oxygen levels. Although NADH signals are not calibrated in absolute units, their trend monitoring is important for the interpretation of physiological or pathological situations. To understand tissue function better, the multiparametric approach has been developed where NADH serves as the key parameter. The development of new light sources in UV and visible spectra has led to the development of small compact units applicable in clinical conditions for better diagnosis of patients.
Effects of a Cannabinoid Agonist on Spinal Nociceptive Neurons in a Rodent Model of Neuropathic Pain
Authors: Liu Cheng , Walker J. Michael
Published: August 2006

The effects of the synthetic cannabinoid WIN 55,212–2 on heat-evoked firing of spinal wide dynamic range (WDR) neurons were examined in a rodent model of neuropathic pain. Fifty-eight WDR neurons (1 cell/animal) were recorded from the ipsilateral spinal dorsal horns of rats with chronic constriction injury (CCI) and sham-operated controls. Relative to sham-operated controls, neurons recorded in CCI rats showed elevations in spontaneous firing, noxious heat-evoked responses, and afterdischarge firing as well as increases in receptive field size. WIN 55,212–2 (0.0625, 0.125, and 0.25 mg/kg, intravenous) dose-dependently suppressed heat-evoked activity and decreased the receptive field areas of dorsal horn WDR neurons in both nerve injured and control rats with a greater inhibition in CCI rats. At the dose of 0.125 mg/kg iv, WIN 55,212–2 reversed the hyperalgesia produced by nerve injury. The effect of intravenous administration of WIN 55,212–2 appears to be centrally mediated because administration of the drug directly to the ligated nerve did not suppress the heat-evoked neuronal activity in CCI rats. Pretreatment with the cannabinoid CB1receptor antagonists SR141716A or AM251, but not the CB2antagonist SR144528, blocked the effects. These results provide a neural basis for reports of potent suppression by cannabinoids of the abnormal sensory responses that result from nerve injury.
Mechanisms Underlying Type I mGluR-Induced Activation of Lobster Gastric Mill Neurons
Authors: Levi Rafael , Selverston Allen I.
Published: August 2006

In addition to ionotropic effects, glutamate and acetylcholine have metabotropic modulatory effects on many neurons. Here we show that in the stomatogastric ganglion of the lobster, glutamate, one of the main ionotropic neurotransmitters, modulates the excitability of gastric mill neurons. The neurons in this well-studied system produce rhythmic output to a subset of lobster foregut muscles. Recently, metabotropic glutamate receptor (mGluR) agonists were suggested as modulators of the rhythmic output, in addition to the previously described muscarinic modulation by acetylcholine. However, the cellular mechanisms responsible for these effects on the pattern are not known. Using intracellular recording methods and calcium imaging, we show that glutamate has an excitatory effect on specific neurons in the stomatogastric ganglion, which is mediated by mGluRs. Responses to the application of mGluR type I agonists are transient oscillations in the system, probably arising from network interactions. We show that the excitatory effect is sensitive to phospholipase-C and IP3and is G-protein dependent. The G-protein dependency was demonstrated by GDPβS and GTPγS injection into identified neurons. The depolarizations and oscillations were accompanied by an increase of intracellular Ca2+levels and correlated Ca2+oscillations. By using cyclopiazonic acid, an endoreticular Ca2+uptake inhibitor, we show that some internal calcium release may augment the response, but is not crucial for its production. Interestingly, although Ca2+concentration increase is typically associated with the phosphoinositide pathway, in the lobster, the Ca2+concentration increase—either voltage dependent or independent—cannot account for the observed depolarization.
Locally-Adaptive and Memetic Evolutionary Pattern Search Algorithms
Authors: Hart William E.
Published: August 2006

Abstrac

Recent convergence analyses of evolutionary pattern search algorithms (EPSAs) have shown that these methods have a weak stationary point convergence theory for a broad class of unconstrained and linearly constrained problems. This paper describes how the convergence theory for EPSAs can be adapted to allow each individual in a population to have its own mutation step length (similar to the design of evolutionary programing and evolution strategies algorithms). These are called locally-adaptive EPSAs (LA-EPSAs) since each individual's mutation step length is independently adapted in different local neighborhoods. The paper also describes a variety of standard formulations of evolutionary algorithms that can be used for LA-EPSAs. Further, it is shown how this convergence theory can be applied to memetic EPSAs, which use local search to re.ne points within each iteration.
Women’s Choices Within Market Constraints: Re-Visioning Access to and Participation in the Superintendency
Authors: Mahitivanichcha Kanya , Rorrer Andrea K.
Published: August 2006

Purpose: In this article, the authors highlight three constraints—structural time crisis (Schor, 1991) ideal worker norms (Williams, 2000), and labor and occupational queues (Reskin & Roos, 1990; Strober, 1992)—on the decisions and choices of women seeking to advance to and hold positions in the superintendency.

Proposed Conceptual Argument: The authors contribute to and extend the extant body of work by integrating a conceptual framework that emerges from feminist economics theory and feminist organizational theory. The authors use this framework to analyze the current access and representation of women in the superintendency.

Conclusions: What exists today is an institutionalized, systemic pattern in the market that is robust and resistant to change. However, this discussion contributes to our understanding of women’s experiences in advancing to administrative positions generally, and the superintendency particularly, and advances the way we organize administration and administrative work to be more representative of women and eliminate constraints on women’s choices.
“A Job Too Big for One”: Multiple Principals and Other Nontraditional Approaches to School Leadership
Authors: Grubb W. Norton , Flessa Joseph J.
Published: August 2006

Background: Current federal, state, and local school accountability measures as well as policy initiatives that call for improved leadership have placed increasing demands on principals. Many districts face shortages of appropriate candidates for the job; popularly, this shortage is explained by the fact that simply too few hero-principals exist for all openings available, particularly in high-needs districts. An alternative to finding the perfect—and rare—candidate for an increasingly untenable position is to restructure the job itself.

Purpose: This article examines 10 schools that have adopted alternative structures: schools with two principals, three principals, and rotating principals and a school with the principal’s duties distributed among teachers. These 10 sites provide examples of alternative ways of organizing school leadership with varying benefits and challenges.

Research Methods: Data collection at the 10 schools included site visits conducted by a team of researchers, interviews with principals, teacher leaders, and district supervisors. Observational and interview protocols were adapted from the Northwestern University Distributed Leadership Study. These protocols focus on uncovering not only how school site leaders explain their decisions but also on providing evidence of what those decisions are. Interview and observational data were organized into thematic codes to permit cross-case comparison.

Findings: We observed the idiosyncratic ways in which schools and districts approached the policy dilemmas associated with attempts to change the default administrative structure of principal and assistant principal. Some schools with coprincipals, for example, thrived; others struggled. Where local school sites participated actively with the policy-making process that produced these arrangements, the alternative seemed viable. Where alternatives were imposed without school input, implementation floundered. The findings analyze the origins of the reforms, school site roles, costs and benefits, the role of the district, and the long-term stability of the approach.

Implications: In this article, we describe the experiences of 10 schools that have experimented with alternative arrangements for school site leadership. These experiences offer schools, districts, school boards, and researchers a series of questions to consider as they contemplate reforming the principalship itself rather than (or in addition to) preparing and searching for competent principals.
Researchers at the Gate: Factors Influencing Districts’ Right of Entry Decisions
Authors: Melnick Steven A. , Henk William A.
Published: August 2006

Background: The No Child Left Behind legislation creates an increased need for new school-based empirical studies whose implementation will depend largely on researchers’ access to various school populations and records. Access decisions are typically made by superintendents, or their designees, functioning as gatekeepers who control right of entry. Understanding the factors driving these decisions could enhance the desirability of proposals and increase access rates for quantitative and qualitative researchers alike.

Purpose: The purpose of this research was to query districts about four key access factors including (a) researcher trustworthiness, (b) associated risks, (c) costs and benefits, and (d) potential contribution to the field.

Research Method: This study used a series of interviews followed by a systematic survey. Participants: Ten superintendents were interviewed followed by a survey of 310 districts in Connecticut, Illinois, and Pennsylvania.

Findings: Although trustworthiness was expected to supercede other factors, districts reported greater interest in elements of risk and in research having widespread educational value. Costs and material benefits (e.g., equipment, credit, and compensation) were not highly emphasized nor relatively important. Professional development, planning, and instructional benefits mattered more.

Implications for Research and Practice: Given the increasing emphasis on scientifically based research for school decision-making and program reform, the present study is notable for two reasons. First, it provides researchers with insights into the decision-making process involved in granting permission to conduct research in the schools. Second, it can help to improve the quality of proposals received by school districts, thereby increasing the likelihood of positive right-of-entry decisions and resulting in better informed decisions.