bluuebunny/crossref_metadata_2025 huggingface dataset:
An Elementary Overview of the Selection of Materials for Service in Oxygen-enriched Environments
Authors: Davis Samuel Edgar
Published: January 2013

The process of selecting materials for use in oxygen or oxygen-enriched environments is one that continues to be investigated by many industries because of the importance to those industries of oxygen systems. There are several excellent resources available to assist oxygen systems design engineers and end-users, with the most comprehensive being the second edition of ASTM MNL-36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation and Maintenance. ASTM also makes available several standards for oxygen systems. However, the ASTM publications are extremely detailed and typically are designed for professionals who already possess a working knowledge of oxygen systems. No notable resource exists, whether an ASTM publication or that of some other organization, that can be used to educate engineers or technicians who have no prior knowledge of the nuances of oxygen system design and safety. This paper will fill the void for information needed by organizations that design or operate oxygen systems. The information in this paper is not new, but it provides a concise and easily understood summary of the selection of materials for oxygen systems. This paper will serve well as an employee's first introduction to oxygen system materials selection, and probably as the employee's first introduction to ASTM.
Development of a Liquid Oxygen Facility for Rocket Engine Testing
Authors: Mulkey H. W. , Lineberry D. M.
Published: January 2013

The Propulsion Research Center at the University of Alabama Huntsville has developed a liquid oxygen propellant feed system that has advanced into operational maturity. In support of safe system functional development, an oxygen compatibility and hazards assessment was completed in order to identify and minimize operational risks. The objective of this effort was to minimize potential risks that might have been overlooked in the initial design phase or resulted from a discontinuity between design and fabrication. The effort involved an internal review of the operating procedures and the system configuration, as well as an overall review by an oxygen safety engineering consultant. This paper outlines the review procedures applied to the oxygen propellant systems, summarizes the significant findings, and details configuration changes made to the system. The review process identified several areas in which reliance on procedural control, without compromising safe system operation, could be reduced or removed through design changes. Such changes were implemented so as to create a more fault tolerant system and minimize risks to test equipment, system hardware, and test personnel. Major upgrades included initiatives to manage the oxygen risk and mitigate specific oxygen ignition mechanisms. Oxygen compatible materials and facility configuration changes enabled safer experimentation in the demonstration testing of the cryogenic propellant facility. The findings presented in this paper represent the system changes made in an effort to increase safety and decrease the risk of fire in order to achieve a low probability of ignition and a low consequence of ignition.
Pressure Dependence of Aluminum Ignition in Gaseous Oxygen and Possible Ignition Mechanisms in Brazed Aluminum Heat Exchangers
Authors: Crayssac Frédéric , Rostaing Jean Christophe , Werlen Etienne , Sun Lianming , Houghton Patrick , Kleinberg William , Coste Frédéric
Published: January 2013

The ignition of aluminum foils in gaseous oxygen was experimentally tested using a diode laser as the energy source, which provided a well-controlled, accurate, and reproducible method of ignition. The tests were conducted under different conditions in terms of oxygen pressure, oxygen purity, aluminum thickness, and gas velocity. The aluminum foils tested were between 0.2 mm and 0.45 mm thick, a range typical of fins contained in brazed aluminum heat exchangers (BAHXs) used in air separation units (ASUs). The experimental apparatus was composed of a pressure vessel in which a single aluminum test sample was placed. The vessel contained an optical window that allowed a short laser pulse of known power to be applied to the aluminum sample. The energy dose was systematically varied in order to identify the threshold ignition energy, defined as the point at which the probability of aluminum combustion with propagation beyond the laser spot was 50 %. The experimental results show that O2 pressure has no significant effect on the ignition energy of aluminum over the pressure range tested (10 bar to 120 bar). This conclusion holds for both standard commercial grade purity O2 (99.8 %) and high purity O2 (99.99 %), as well as for gas velocities higher than typically encountered in ASU BAHXs. Heat conduction calculations indicate that aluminum ignition occurs when the laser spot temperature reaches the melting point of the passivating oxide layer (about 2200 K to 2300 K). The heat conduction model accurately explains the dependence of the ignition energy on the aluminum sample thickness. These test results have been used in assessing the risk of ignition of BAHXs used in high pressure oxygen service in ASUs.
Auto-Ignition and Combustion Properties of Iron/Steel Micro-Particles in Oxygen Atmospheres Heated by Rapid Compression
Authors: Leschevich Vladimir V. , Penyazkov Oleg G. , Rostaing Jean-Christophe
Published: January 2013

Accumulated deposits of metal particles contaminating high-pressure oxygen piping systems represent a strongly reactive and highly adiabatic medium. They are prone to ignition following an initial thermal perturbation or heat confinement and then will apply an extremely high temperature pulse to adjacent surfaces, thus becoming a factor enhancing the severity of accidental fires. In order to investigate metal powder layers' ignitability and burning, a rapid compression machine was used for generating, at a given time-origin, heated oxygen atmospheres at programmed pressures of 0.5 to 28 MPa and temperatures of 550 to 1100 K. Critical conditions for auto-ignition were determined as a function of particle size for two commercial iron powders with particle sizes ranging from 1 to 5 μm and three real residual powders from industrial installations. A first major finding is that iron/steel particle deposits can be easily ignited in rapidly heated oxygen atmospheres at temperatures considerably lower than the iron melting point. Moreover, this critical temperature diminishes significantly with increasing oxygen pressure. The temperature of burning particles was measured with a time resolution of 4 μs by means of a novel photoemission technique. It was seen that the temperature can quickly rise up to 3100 K and then fall to 1850 ± 50 K. An extensive database is available for the development and validation of models describing fires in various piping elements with specified particulate contamination, to be used in order to identify circumstances for especially severe accidents.
Combustion Products of Bulk Aluminum Rods Burning in High-Pressure Oxygen
Authors: Plagens Owen , Lynn David , Castillo Martin , Paulos Todd , Steinberg Theodore
Published: January 2013

Characterization of the combustion products released during the burning of commonly used engineering metallic materials may aid in material selection and risk assessment for the design of oxygen systems. The characterization of combustion products in regard to size distribution and morphology gives useful information for systems addressing fire detection. Aluminum rods (3.2-mm-diameter cylinders) were vertically mounted inside a combustion chamber and ignited in pressurized oxygen by resistively heating an aluminum/palladium igniter wire attached to the bottom of the test sample. This paper describes the experimental work conducted to establish the particle-size distribution and morphology of the resultant combustion products collected after the burning was completed and subsequently analyzed. In general, the combustion products consisted of a re-solidified oxidized slag and many small hollow spheres of size ranging from about 500 nm to 1000 μm in diameter, surfaced with quenched dendritic and grain-like structures. The combustion products were characterized using optical and scanning electron microscopy.
Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres
Authors: Stoltzfus Joel M. , Jeffers Nathan , Gallus Timothy D.
Published: January 2013

The flammability in oxygen-enriched atmospheres of commercially pure (CP) titanium rods as a function of diameter and test gas pressure was determined. Test samples of varying diameters were ignited at the bottom and burned upward in 70 % O2/balance N2 and in 99.5+ % O2 at various pressures. The burning rate of each ignited sample was determined by observing the apparent regression rate of the melting interface (RRMI) of the burning samples. The burning rate or RRMI increased with decreasing test sample diameter and with increasing test gas pressure and oxygen concentration. The oxygen concentration had a much more marked affect on the burning rate than oxygen pressure.
Impacts of Hydrated Lime Injection on Electrostatic Precipitator Performance
Authors: Mastropietro Robert A.
Published: January 2013

Electrostatic precipitators (ESPs), which are particulate collectors, are now used as part of the flue gas scrubbing strategy. In these combined systems, hydrated lime is injected into the flue gas ahead of the ESP to either neutralize or adsorb a gaseous pollutant. Then the ESP must remove the combined fly ash from fuel combustion, plus the unreacted rea-gent and reaction products. The primary parameter in ESP performance is the particulate resistivity. Particulate resistivity is a measure of how well the particulate, when deposited on the ESP collecting electrodes, conducts electricity to ground. Variations in resistivity from optimum to extremely high can change ESP particulate emissions by significant amounts. When injecting hydrated lime into the flue gas, we must be very concerned with the impacts of injected lime and reaction products on combined particulate resistivity in the ESP. Resistivity will have a greater impact on ESP performance than all other parameters combined. This paper is a study of the impacts on resistivity from injecting hydrated lime to treat flue gas. Lime and some of its reaction products are known to be somewhat high in resistivity, and its addition to the fly ash could be a concern in performance modeling. The impact of typical lime injection rates will be analyzed for impacts on fly ash resistivity. In addition, the - paper will also discuss the impacts of these resistivity changes on ESP particulate emissions.
Lime Stabilization of Subgrade Soils for Structural Purposes: Past Evidence and Future Needs
Authors: Little Dallas N.
Published: January 2013

Stabilization of mechanically and volumetrically unstable clay soils is well supported in the literature, and stabilization of clay soils, and in particular highly plastic clay soils, has been a popular practice for decades. However, the basis for this popularity has largely been construction expediency provided by the physico-chemical changes that occur due to calcium ion saturation of the clay soil lattice and pozzolanic reactions between lime and (primarily) clay minerals and amorphous silicates. A more careful look at the improvement derived by lime stabilization of clay soils in terms of resilient modulus improvements especially at near saturation moisture contents, reduction in the rate of accumulation of plastic strains and the substantial improvements in volumetric stability makes it appropriate to take a closer look at the structural beneficiation of lime stabilization in mechanistic-empirical pavement design. The progression toward a more mechanistic design methodology, i.e., through the American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG), offers an opportunity to define research activities contemporary with MEPDG in order to take full advantage of structural and volumetric stability improvements that can be realized through lime stabilization. A short and directed review of the pertinent literature toward this direction, improvements in mechanical and volumetric stability that can be derived through lime stabilization, and research topics that need to be addressed in order to improve the utility of how lime stabilized layers are addressed in the MEPDG and other mechanistic pavement design approaches are presented.
Chromatic Processing in the Anterior Optic Tubercle of the Honey Bee Brain
Authors: Mota Theo , Gronenberg Wulfila , Giurfa Martin , Sandoz Jean-Christophe
Published: January 2013

Color vision in honey bees (Apis mellifera) has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level by means of electrophysiological intracellular recordings of single neurons. Few visual neurons have been so far characterized in the lateral protocerebrum of bees. Therefore, the possible implication of this region in chromatic processing remains unknown. We performedin vivocalcium imaging of interneurons in the anterior optic tubercle (AOTu) of honey bees upon visual stimulation of the compound eye to analyze chromatic response properties. Stimulation with distinct monochromatic lights (ultraviolet [UV], blue, and green) matching the sensitivity of the three photoreceptor types of the bee retina induced different signal amplitudes, temporal dynamics, and spatial activity patterns in the AOTu intertubercle network, thus revealing intricate chromatic processing properties. Green light strongly activated both the dorsal and ventral lobes of the AOTu's major unit; blue light activated the dorsal lobe more while UV light activated the ventral lobe more. Eye stimulation with mixtures of blue and green light induced suppression phenomena in which responses to the mixture were lower than those to the color components, thus concurring with color-opponent processing. These data provide evidence for a spatial segregation of color processing in the AOTu, which may serve for navigation purposes.
FoxP2 Regulates Neurogenesis during Embryonic Cortical Development
Authors: Tsui David , Vessey John P. , Tomita Hideaki , Kaplan David R. , Miller Freda D.
Published: January 2013

The transcription factor FoxP2 has been associated with the development of human speech but the underlying cellular function of FoxP2 is still unclear. Here we provide evidence that FoxP2 regulates genesis of some intermediate progenitors and neurons in the mammalian cortex, one of the key centers for human speech. Specifically, knockdown of FoxP2 in embryonic cortical precursors inhibits neurogenesis, at least in part by inhibiting the transition from radial glial precursors to neurogenic intermediate progenitors. Moreover, overexpression of human, but not mouse, FoxP2 enhances the genesis of intermediate progenitors and neurons. In contrast, expression of a human FoxP2 mutant that causes vocalization deficits decreases neurogenesis, suggesting that in the murine system human FoxP2 acts as a gain-of-function protein, while a human FoxP2 mutant acts as a dominant-inhibitory protein. These results support the idea that FoxP2 regulates the transition from neural precursors to transit-amplifying progenitors and ultimately neurons, and shed light upon the molecular changes that might contribute to evolution of the mammalian cortex.
No Consistent Relationship between Gamma Power and Peak Frequency in Macaque Primary Visual Cortex
Authors: Jia Xiaoxuan , Xing Dajun , Kohn Adam
Published: January 2013

Neural activity in the gamma frequency range (“gamma”) is elevated during active cognitive states. Gamma has been proposed to play an important role in cortical function, although this is debated. Understanding what function gamma might fulfill requires a better understanding of its properties and the mechanisms that generate it. Gamma is characterized by its spectral power and peak frequency, and variations in both parameters have been associated with changes in behavioral performance. Modeling studies suggest these properties are co-modulated, but this has not been established. To test the relationship between these properties, we measured local field potentials (LFPs) and neuronal spiking responses in primary visual cortex of anesthetized monkeys, for drifting sinusoidal gratings of different sizes, contrasts, orientations and masked with different levels of noise. We find that there is no fixed relationship between LFP gamma power and peak frequency, and neither is related to the strength of spiking activity. We propose a simple model that can account for the complex stimulus dependence we observe, and suggest that separate mechanisms determine gamma power and peak frequency.
Effects of Digesting Chondroitin Sulfate Proteoglycans on Plasticity in Cat Primary Visual Cortex
Authors: Vorobyov Vasily , Kwok Jessica C.F. , Fawcett James W. , Sengpiel Frank
Published: January 2013

Monocular deprivation (MD) during a critical period of postnatal development produces significant changes in the anatomy and physiology of the visual cortex, and the deprived eye becomes amblyopic. Extracellular matrix molecules have a major role in restricting plasticity such that the ability to recover from MD decreases with age. Chondroitin sulfate proteoglycans (CSPGs) act as barriers to cell migration and axon growth. Previous studies showing that degradation of CSPGs by the bacterial enzyme chondroitinase can restore plasticity in the adult rat visual cortex suggest a potential treatment for amblyopia.

Here MD was imposed in cats from the start of the critical period until 3.5 months of age. The deprived eye was reopened, the functional architecture of the visual cortex was assessed by optical imaging of intrinsic signals, and chondroitinase was injected into one hemisphere. Imaging was repeated 1 and 2 weeks postinjection, and visually evoked potentials (VEPs) and single-cell activity were recorded.

Immunohistochemistry showed that digestion of CSPGs had been successful. After 2 weeks of binocular exposure, some recovery of deprived-eye responses occurred when chondroitinase had been injected into the hemisphere contralateral to that eye; when injected into the ipsilateral hemisphere, no recovery was seen. Deprived-eye VEPs were no larger in the injected hemisphere than in the opposite hemisphere. The small number of neurons dominated by the deprived eye exhibited poor tuning characteristics.

These results suggest that despite structural effects of chondroitinase in adult cat V1, plasticity was not sufficiently restored to enable significant functional recovery of the deprived eye.
Signals for Previous Goal Choice Persist in the Dorsomedial, but Not Dorsolateral Striatum of Rats
Authors: Kim Hoseok , Lee Daeyeol , Jung Min Whan
Published: January 2013

The cortico-basal ganglia network has been proposed to consist of parallel loops serving distinct functions. However, it is still uncertain how the content of processed information varies across different loops and how it is related to the functions of each loop. We investigated this issue by comparing neuronal activity in the dorsolateral (sensorimotor) and dorsomedial (associative) striatum, which have been linked to habitual and goal-directed action selection, respectively, in rats performing a dynamic foraging task. Both regions conveyed significant neural signals for the animal's goal choice and its outcome. Moreover, both regions conveyed similar levels of neural signals for action value before the animal's goal choice and chosen value after the outcome of the animal's choice was revealed. However, a striking difference was found in the persistence of neural signals for the animal's chosen action. Signals for the animal's goal choice persisted in the dorsomedial striatum until the outcome of the animal's next goal choice was revealed, whereas they dissipated rapidly in the dorsolateral striatum. These persistent choice signals might be used for causally linking temporally discontiguous responses and their outcomes in the dorsomedial striatum, thereby contributing to its role in goal-directed action selection.
Genetic Analysis of Synaptotagmin C2 Domain Specificity in Regulating Spontaneous and Evoked Neurotransmitter Release
Authors: Lee Jihye , Guan Zhuo , Akbergenova Yulia , Littleton J. Troy
Published: January 2013

Synaptic vesicle fusion mediates communication between neurons and is triggered by rapid influx of Ca2+. The Ca2+-triggering step for fusion is regulated by the synaptic vesicle transmembrane protein Synaptotagmin 1 (Syt1). Syt1 contains two cytoplasmic C2 domains, termed C2A and C2B, which coordinate Ca2+binding. Although C2A and C2B share similar topology, binding of Ca2+ions to the C2B domain has been suggested as the only critical trigger for evoked vesicle release. If and how C2A domain function is coordinated with C2B remain unclear. In this study, we generated a panel of Syt1 chimeric constructs inDrosophilato delineate the unique and shared functions of each C2 domain in regulation of synaptic vesicle fusion. Expression of Syt 1 transgenes containing only individual C2 domains, or dual C2A-C2A or C2B-C2B chimeras, failed to restore Syt1 function in asyt1−/−null mutant background, indicating both C2A and C2B are specifically required to support fast synchronous release. Mutations that disrupted Ca2+binding to both C2 domains failed to rescue evoked release, but supported synaptic vesicle docking and endocytosis, indicating that these functions of Syt1 are Ca2+-independent. The dual C2 domain Ca2+-binding mutant also enhanced spontaneous fusion while dramatically increasing evoked release when coexpressed with native Syt1. Together, these data indicate that synaptic transmission can be regulated by Syt1 multimerization and that both C2 domains of Syt1 are uniquely required for modulating Ca2+-independent spontaneous fusion and Ca2+-dependent synchronous release.
Periadolescent Exposure to the NMDA Receptor Antagonist MK-801 Impairs the Functional Maturation of Local GABAergic Circuits in the Adult Prefrontal Cortex
Authors: Thomases Daniel R. , Cass Daryn K. , Tseng Kuei Y.
Published: January 2013

A developmental disruption of prefrontal cortical inhibitory circuits is thought to contribute to the adolescent onset of cognitive deficits observed in schizophrenia. However, the developmental mechanisms underlying such a disruption remain elusive. The goal of this study is to examine how repeated exposure to the NMDA receptor antagonist dizocilpine maleate (MK-801) during periadolescence [from postnatal day 35 (P35) to P40] impacts the normative development of local prefrontal network response in rats.In vivoelectrophysiological analyses revealed that MK-801 administration during periadolescence elicits an enduring disinhibited prefrontal local field potential (LFP) response to ventral hippocampal stimulation at 20 Hz (beta) and 40 Hz (gamma) in adulthood (P65–P85). Such a disinhibition was not observed when MK-801 was given during adulthood, indicating that the periadolescent transition is indeed a sensitive period for the functional maturation of prefrontal inhibitory control. Accordingly, the pattern of prefrontal LFP disinhibition induced by periadolescent MK-801 treatment resembles that observed in the normal P30–P40 prefrontal cortex (PFC). Additional pharmacological manipulations revealed that these developmentally immature prefrontal responses can be mimicked by single microinfusion of the GABAAreceptor antagonist picrotoxin into the normal adult PFC. Importantly, acute administration of the GABAA-positive allosteric modulator Indiplon into the PFC reversed the prefrontal disinhibitory state induced by periadolescent MK-801 to normal levels. Together, these results indicate a critical role of NMDA receptors in regulating the periadolescent maturation of GABAergic networks in the PFC and that pharmacologically induced augmentation of local GABAA-receptor-mediated transmission is sufficient to overcome the disinhibitory prefrontal state associated with the periadolescent MK-801 exposure.
Sustained Activation of ERK1/2 MAPK in Oligodendrocytes and Schwann Cells Enhances Myelin Growth and Stimulates Oligodendrocyte Progenitor Expansion
Authors: Ishii Akihiro , Furusho Miki , Bansal Rashmi
Published: January 2013

Myelin is a biologically active membrane receiving and processing signals from axons. Although much is known about its structure and molecular composition, the intracellular signal transduction pathways, active during specific phases of myelinogenesis for regulating myelin formation, remain poorly understood. Recent genetic loss-of-function studies have suggested a key role of extracelluar signal-regulated kinases-1 and -2 (ERK1/2), downstream mediators of mitogen-activated protein kinases (MAPKs), in promoting CNS and PNS myelination. In contrast, other studies, largelyin vitro, have suggested that activation of ERK1/2 pathway can be detrimental for glial cell function and myelination. Given these conflicting reports, we investigated the effects of cell-autonomous activation of ERK1/2 in glial cells during developmental myelination in the intact CNS and PNS. Two lines of transgenic mice with sustained activation of ERK1/2 in oligodendrocyte progenitors (OPCs), oligodendrocytes, and Schwann cells were generated. Consistent with our loss-of-function studies, gain of ERK1/2 function in oligodendrocyte-lineage cells significantly increased myelin thickness, independent of oligodendrocyte differentiation or initiation of myelination. Additionally, increased activation of ERK1/2 in OPCs during early development resulted in transient hyperproliferation and overproduction of OPCs but generation of normal numbers of myelinating oligodendrocytes. Thus, thesein vivostudies suggest a beneficial biphasic requirement of ERK1/2 during developmental myelination in the CNS, deployed first during early stages of the oligodendrocyte lineage for promoting OPC expansion and then redeployed later in myelinating oligodendrocytes for promoting myelin growth. Furthermore, Schwann cells with activated ERK1/2 hypermyelinate PNS axons, suggesting that ERK1/2 signaling is a conserved mechanism that promotes both CNS and PNS developmental myelination.
Determinants of Perceived Immigrant Job Threat in the American States
Authors: Wallace Michael , Figueroa Rodrigo
Published: January 2013

In the United States, the 2000s were marked by record numbers of immigrants and heightened levels of pro- and anti-immigrant agitation. As a result, research investigating anti-immigrant prejudice in the United States and other societies has surged. In this article, the authors investigate the determinants of perceived immigrant job threat in the fifty U.S. states in 2005. They draw upon three theoretical perspectives that dominate the study of prejudice—group threat theory, contact theory, and cultural theory—but move beyond these established theories to adduce three new perspectives, which they label economic competition, labor market deregulation, and globalization. The authors find support for all six perspectives. The three new perspectives augment, rather than supplant, the traditional theories. The authors find that levels of perceived immigrant job threat tend to increase in settings where there is economic stagnation, where labor unions are growing weaker, where the minimum wage is low, and where corporate restructuring has taken place.
Antitumoral drug loaded in TEOS nanoparticles
Authors: Araújo Ana Paula V. , Lunardi Claure N. , Gomes Anderson J.
Published: January 2013

Methotrexate (MTX), is a potent immunomodulating drug and widely used in the treatment of cancer, psoriasis and others disease. Despite its efficacy, the use of MTX is greatly limited due to its toxicity. To solve this problem, we prepared nanoparticles of tetraethyl orthosilicate (NP-TEOS) containing the compound methotrexate (MTX), by the sol-gel method. This drug delivery system (DDS) showed a loading efficiency of 39.7%. Size distribution studies were performed with dynamic light scattering and scanning electron microscopy revealing that these particles were spherical in shape, with a mean diameter between 140-430 nm and a low polydispersity (0.12 – 0.26). Also the particles displayed a low tendency toward aggregation which was confirmed by the low zeta potential -61.4 mV. Profile release showed a slow release loaded with MTX (PBS buffer pH = 7.4). The slow release can be attributed to the low porosity of the NP-TEOS and the extremely low diffusivity of MTX in aqueous media. B16-F10 cells were used to assay the toxicity and uptake of NP-TEOS showing to be nontoxic without MTX making a good candidate for DDS.
Pseudotetraploid Clone with Structural Chromosomal Rearrangements in a Chondromyxoid Fibroma: A Case Report
Authors: Liu Jinglan , Ownbey Robert T. , Boc Steven F. , Pezanowski Donna M. , Patel Dilipkumar M. , Sadri Soorena , Vincent Gregory A. , de ChadaréVian Jean-Pierre
Published: January 2013

Chondromyxoid fibroma is a rare benign tumor accounting for 1–2% of primary bone tumors. Most of the patients are young males in the 2nd and 3rd decades of life. Metaphyses of long bones are predominantly affected. The histology of this tumor is well established, but its genetic mechanism remains poorly characterized. To our knowledge, only 22 abnormal cytogenetic analyses have been reported, and all contained diploidy or near-diploidy karyograms as their primary event, and inv(6)(p25)(q13) and rearrangements involving regions 6p23-25, 6q12-15, and 6q23-27 constituted a recurrent observation. In this report, a pseudotetraploidy tumor clone with multiple numerical and structural aberrations involving 6p23 as well as other chromosomal loci was identified in a chondromyxoid fibroma from the metaphysis of the left fibula of an 18-year-old male, which has not been reported. The finding may relate to the atypical-looking large cells often seen in this benign tumor.
Endoscopic resection of colloid cyst in normal-sized ventricular system
Authors: Margetis Konstantinos , Souweidane Mark M.
Published: January 2013

Endoscopic resection of colloid cyst in patients with normal-sized ventricular system is challenging, because the limited intraventricular space increases the risk of injuring eloquent nervous structures and critical blood vessels. The utilization of frameless stereotaxy and tissue shaving device facilitates the procedure. An important operative step is the ventricular insufflation that allows for an endoscope introduction without causing inadvertent injury to the caudate nucleus. The attached clip shows the basic operative steps of the procedure. In this clip the solid colloid cyst contents necessitated an en-block colloid cyst resection, in lieu of initially aspirating the cyst contents and subsequently removing the cyst walls.

The video can be found here: http://youtu.be/zzYYZEsd-uk.
Endoscopic treatment of a third ventricle choroid plexus cyst
Authors: de Lara Danielle , Ditzel Filho Leo F. S. , Muto Jun , Prevedello Daniel M.
Published: January 2013

Choroid plexus cysts are frequent benign intraventricular lesions that infrequently cause symptoms, usually in the form of obstructive hydrocephalus. These instances are even less common in the adult population. When warranted, treatment seeks to reestablish cerebrospinal fluid flow and does not necessarily require resection of the cyst itself. Hence, endoscopic exploration of the ventricles with subsequent cyst ablation is the current treatment of choice for these lesions.

Herein we present the case of a 25-year-old female patient with a 3-week history of intermittent headaches. Investigation with computerized tomography (CT) of the head detected supratentorial hydrocephalus, with enlargement of the lateral and third ventricles. Magnetic resonance imaging revealed a homogeneous cystic lesion in the third ventricle. A right-sided, pre-coronal burr hole was carried out, followed by endoscopic exploration of the ventricular system. A third-ventriclostomy was performed. With the aid of the 30-degrees endoscope, a cyst arising from the choroid plexus was visualized along the posterior portion of the third ventricle, obstructing the aqueduct opening. The cyst was cauterized until significant reduction of its dimensions was achieved and the aqueduct opening was liberated. Postoperative recovery was without incident and resolution of the hydrocephalus was confirmed by CT imaging. The patient reports complete improvement of her headaches and has been uneventfully followed since surgery.

The video can be found here: http://youtu.be/XBtj_SqY07Q.
Microsurgical resection of giant intraventricular meningioma
Authors: Liu James K.
Published: January 2013

Intraventricular meningiomas are rare tumors, accounting for approximately 0.5 to 3% of all intracranial meningiomas. The majority arise in the atrium of the lateral ventricle. The surgical management of these tumors remains a considerable challenge because of their deep location and proximity to critical structures. Complete resection, if safely possible, should be the goal of surgery since this results in the best rates of local control. Although various approaches exist to access the lateral ventricular system, selection of the optimal approach should be individualized to the patient based upon the location of the tumor within the ventricle, the tumor size, the origin of the vascular supply to the tumor, and the relationship to neighboring neurovascular structures at risk. In this operative video manuscript, the author demonstrates an illustrative step-by-step technique for microsurgical resection of a giant intraventricular meningioma of the left atrium via a transcortical parieto-occipital approach. The patient illustrated in this video presented with a large recurrent meningioma (> 5 cm) approximately 10 years after the initial resection. The tumor had grown around a pre-existing shunt catheter and resulted in loculated hydrocephalus. A complete resection and shunt revision were both performed at the same sitting. The operative technique and surgical nuances, including the surgical approach, intradural tumor removal, closure, and management of hydrocephalus are illustrated in this video atlas.

The video can be found here: http://youtu.be/vpdmZ1ccWSM.
Development and Characterization of Biodegradable Composite Films Based on Gelatin Derived from Beef, Pork and Fish Sources
Authors: Nur Hanani Zainal , Beatty Eddie , Roos Yrjo , Morris Mick , Kerry Joseph
Published: January 2013

The objectives of this study were to develop composite films using various gelatin sources with corn oil (CO) incorporation (55.18%) and to investigate the mechanical and physical properties of these films as potential packaging films. There were increases (p < 0.05) in the tensile strength (TS) and puncture strength (PS) of films when the concentration of gelatin increased. The mechanical properties of these films were also improved when compared with films produced without CO. Conversely, the water barrier properties of composite films decreased (p < 0.05) when the concentration of gelatin in composite films increased. Comparing with pure gelatin films, water and oxygen barrier properties of gelatin films decreased when manufactured with the inclusion of CO.
Health Insurance, Socio-Economic Position and Racial Disparities in Preventive Dental Visits in South Africa
Authors: Ayo-Yusuf Imade , Ayo-Yusuf Olalekan , Olutola Bukola
Published: January 2013

This study sought to determine the contributions of socio-economic position and health insurance enrollment in explaining racial disparities in preventive dental visits (PDVs) among South Africans. Data on the dentate adult population participating in the last South African Demographic and Health Survey conducted during 2003–2004 (n = 6,312) was used. Main outcome measure: Reporting making routine yearly PDVs as a preventive measure. Education, material wealth index and nutritional status indicated socio-economic position. Multi-level logistic regression analysis was conducted to determine the predictors of PDVs. A variant of Blinder-Oaxaca decomposition analysis was also conducted. Health insurance coverage was most common among Whites (70%) and least common among black Africans (10.1%) in South Africa. Similarly, a yearly PDV was most frequently reported by Whites (27.8%) and least frequently reported among black Africans (3.1%). Lower education and lower material wealth were associated with lower odds of making PDVs. There was significant interaction between location (urban/rural) and education (p = 0.010). The racial and socio-economic differences in PDVs observed in urban areas were not observed in rural areas. In the general dentate population, having health insurance significantly increased the odds of making PDVs (OR = 4.32; 3.04–6.14) and accounted for 40.3% of the White/non-White gap in the probability of making PDVs. Overall, socio-economic position and health insurance enrollments together accounted for 55.9% (95% CI = 44.9–67.8) of the White/non-White gap in PDVs. Interventions directed at improving both socio-economic position and insurance coverage of non-White South Africans are likely to significantly reduce racial disparities in PDVs.
Semi-Synthesis of Labeled Proteins for Spectroscopic Applications
Authors: De Rosa Lucia , Russomanno Anna , Romanelli Alessandra , D'Andrea Luca
Published: January 2013

Since the introduction of SPPS by Merrifield in the 60s, peptide chemists have considered the possibility of preparing large proteins. The introduction of native chemical ligation in the 90s and then of expressed protein ligation have opened the way to the preparation of synthetic proteins without size limitations. This review focuses on semi-synthetic strategies useful to prepare proteins decorated with spectroscopic probes, like fluorescent labels and stable isotopes, and their biophysical applications. We show that expressed protein ligation, combining the advantages of organic chemistry with the easy and size limitless recombinant protein expression, is an excellent strategy for the chemical synthesis of labeled proteins, enabling a single protein to be functionalized at one or even more distinct positions with different probes.
Effects of Spray-Drying and Choice of Solid Carriers on Concentrations of Labrasol® and Transcutol® in Solid Self-Microemulsifying Drug Delivery Systems (SMEDDS)
Authors: Li Liang , Yi Tao , Lam Christopher
Published: January 2013

Solid self-microemulsifying drug delivery systems (SMEDDS) have been used increasingly for improving the bioavailability of hydrophobic drugs. Labrasol® and Transcutol® are used widely as surfactant and solubilizer in the formulation of solid SMEDDS. We investigated the effects of spray-drying and the use of different solid carriers on concentrations of Labrasol® and Transcutol® in solid SMEDDS with scutellarin as the formulated drug. Liquid and gas chromatography tandem mass spectrometry (LC-MS and GC-MS) methods were developed for measuring low concentrations of Labrasol® and Transcutol®. In the preparation of solid SMEDDS, lactose, hydroxypropylmethyl cellulose (HPMC) and microcrystalline cellulose (MCC) were used as solid carriers. Judging from the retention ratios of Labrasol® and Transcutol®, the droplet size of solid SMEDDS increased after spray-drying of liquid SMEDDS, and concentrations of these excipients decreased after the solidifying procedure. In such reduction, Lactose and HPMC were found to preserve Labrasol® and Transcutol® better than MCC during spray-drying, and the resultant droplet sizes were smaller than that of MCC. Labrasol® and Transcutol® showed good thermal stability at 60 °C degree for 10 days. It can be concluded that spray-drying could increase the droplet size of solid SMEDDS and decreased the concentration of Labrasol® and Transcutol® therein, while water-soluble solid carriers could preserve Labrasol® and Transcutol® better than insoluble carriers in the solid SMEDDS.
Contributions of green light to plant growth and development
Authors: Wang Yihai , Folta Kevin M.
Published: January 2013

Light passing through or reflected from adjacent foliage provides a developing plant with information that is used to guide specific genetic and physiological processes. Changes in gene expression underlie adaptation to, or avoidance of, the light‐compromised environment. These changes have been well described and are mostly attributed to a decrease in the red light to far‐red light ratio and/or a reduction in blue light fluence rate. In most cases, these changes rely on the integration of red/far‐red/blue light signals, leading to changes in phytohormone levels. Studies over the last decade have described distinct responses to green light and/or a shift of the blue‐green, or red‐green ratio. Responses to green light are typically low‐light responses, suggesting that they may contribute to the adaptation to growth under foliage or within close proximity to other plants. This review summarizes the growth responses in artificially manipulated light environments with an emphasis on the roles of green wavebands. The information may be extended to understanding the influence of green light in shade avoidance responses as well as other plant developmental and physiological processes.
Gravitropism and mechanical signaling in plants
Authors: Toyota Masatsugu , Gilroy Simon
Published: January 2013

Mechanical stress is a critical signal affecting morphogenesis and growth and is caused by a large variety of environmental stimuli such as touch, wind, and gravity in addition to endogenous forces generated by growth. On the basis of studies dating from the early 19th century, the plant mechanical sensors and response components related to gravity can be divided into two types in terms of their temporal character: sensors of the transient stress of reorientation (phasic signaling) and sensors capable of monitoring and responding to the extended, continuous gravitropic signal for the duration of the tropic growth response (tonic signaling). In the case of transient stress, changes in the concentrations of ions in the cytoplasm play a central role in mechanosensing and are likely a key component of initial gravisensing. Potential candidates for mechanosensitive channels have been identified in Arabidopsis thaliana and may provide clues to these rapid, ionic gravisensing mechanisms. Continuous mechanical stress, on the other hand, may be sensed by other mechanisms in addition to the rapidly adapting mechnaosensitive channels of the phasic system. Sustaining such long‐term responses may be through a network of biochemical signaling cascades that would therefore need to be maintained for the many hours of the growth response once they are triggered. However, classical physiological analyses and recent simulation studies also suggest involvement of the cytoskeleton in sensing/responding to long‐term mechanoresponse independently of the biochemical signaling cascades triggered by initial graviperception events.
Characterization of the mechanical properties of qPlus sensors
Authors: Berger Jan , Švec Martin , Müller Martin , Ledinský Martin , Fejfar Antonín , Jelínek Pavel , Majzik Zsolt
Published: January 2013

In this paper we present a comparison of three different methods that can be used for estimating the stiffness of qPlus sensors. The first method is based on continuum theory of elasticity. The second (Cleveland’s method) uses the change in the eigenfrequency that is induced by the loading of small masses. Finally, the stiffness is obtained by analysis of the thermal noise spectrum. We show that all three methods give very similar results. Surprisingly, neither the gold wire nor the gluing give rise to significant changes of the stiffness in the case of our home-built sensors. Furthermore we describe a fast and cost-effective way to perform Cleveland’s method. This method is based on gluing small pieces of a tungsten wire; the mass is obtained from the volume of the wire, which is measured by optical microscopy. To facilitate detection of oscillation eigenfrequencies under ambient conditions, we designed and built a device for testing qPlus sensors.
MONOGRAFIJA „NUO URVINIO ŽMOGAUS IKI ŠIUOLAIKINIO MEGALOPOLIO“
Authors: Bardauskienė Dalia
Published: January 2013

"Book ‘Monografija „Nuo urvinio žmogaus iki šiuolaikinio megalopolio“’ review."Journal of Architecture and Urbanism, 36(4), pp. 307
KRAŠTOVAIZDŽIO ARCHITEKTĄ ANTANĄ TAURĄ (1912–1988) PRISIMENANT
Authors: Deveikienė Vaiva , Deveikis Steponas
Published: January 2013

"Kraštovaizdžio architektą Antaną Taurą (1912–1988) prisimenant" Journal of Architecture and Urbanism, 36(4), pp. 304-306
WAY SEARCH TO RESEARCH: FROM ACADEMIC EXERCISES IN ARCHITECTURE TO SCIENTIFIC INVESTIGATIONS INTO ACTUAL PROBLEMS / KELIAS Į MOKSLO TYRIMŲ ERDVĘ ARCHITEKTŪROJE: NUO AKADEMINIŲ EKSPERIMENTŲ IKI AKTUALIŲ PROBLEMŲ TYRIMŲ
Authors: Stauskis Gintaras , Eckardt Frank
Published: January 2013

An interest in doctoral studies reflects the overall status of the scientist in the country in general and the role of science in the architect profession in particular. The article analyses the basic channels of how the students of architecture search for and find the ways to transfer themselves from the study area into an academic research environment. In order to figure out general trends and to outline the differences and similarities of doctoral studies that could further facilitate cooperation, the paper presents the thematic outputs of doctoral programmes in architecture schools in Vilnius, Riga, Venice, Jelgava and Weimar. With reference to the example of the Faculty of Architecture, VGTU, the trends towards developing research activities are analysed taking into account three interconnected branches of architecture: urban design, building architecture and landscape architecture. The cooperation and coordination of academic and research activities in wider European space is taking place upon common interest based on the specificities of each school and priorities of the chosen region. The awareness of global and regional processes in architectural research is an important point for the present and coming generations of researchers in Europe as they are building their careers on the basis of investigation into the options of the local applications of global competences in a cross-professional and inter-disciplinary way.

Santrauka

Straipsnio autoriai nagrinėja, kaip studentai iš akademinių studijų atranda kelius į tyrimų erdvę. Remiantis kelių Europos mokyklų patirtimi ir jų pateiktais duomenimis analizuojama magistrantų ir doktarantų skaičiaus kaita, priklausomai nuo bendro urbanistikos, kraštovaizdžio ir pastatų architektūros specialybes studijuojančiųjų skaičiaus. Nors skirtingų mokyklų rodikliai ir skiriasi, aiškėja, kad mokyklos, kuriose yra didesnis studijuojančiųjų skaičius, geriau suformuoja akademinius srautus, turi daugiau studentų antrosios ir trečiosios pakopų studijose ir pasiekia geresnių doktorantūros rezultatų. Autorių nuomone, intensyvesnis architektus rengiančių Europos mokyklų ir pačių tyrėjų bendradarbiavimas yra viena iš svarbiausių priemonių, leidžiančių pasiekti geresnių rezultatų. Jaunųjų mokslininkų konferencijos, tokios kaip VGTU Architektūros fakulteto kasmet organizuojama jaunųjų mokslininkų konferencija „K. Šešelgio skaitymai“, ir ta proga išleidžiamas mokslo žurnalo „Mokslas – Lietuvos ateitis“ numeris sudaro puikias sąlygas doktorantams ir kitiems tyrėjams bendrauti ir keistis akademiniais laimėjimais.