bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of polyisoprenylated methylated protein methyl esterase by polyunsaturated fatty acids and prostaglandins
Authors: Amissah Felix , Taylor Shalina , Duverna Randolph , Ayuk‐Takem Lambert T. , Lamango Nazarius S.
Published: September 2011

Polyisoprenylation is a set of secondary modifications involving proteins whose aberrant activities are implicated in cancers and degenerative disorders. The last step of the pathway involves an ester‐forming polyisoprenylated protein methyl transferase‐ and hydrolytic polyisoprenylated methylated protein methyl esterase (PMPMEase)‐catalyzed reactions. Omega‐3 and omega‐6 PUFAs have been linked with antitumorigeneis and tumorigenesis, respectively. PUFAs are structurally similar to the polyisoprenyl groups and may interfere with polyisoprenylated protein metabolism. It was hypothesized that PUFAs may be more potent inhibitors of PMPMEase than their more polar oxidative metabolites, the prostaglandins. As such, the relative effects of PUFAs and prostaglandins on PMPMEase could explain the association between cyclooxygenase‐2 (COX‐2) expression in tumors, the chemopreventive effects of the non‐steroidal anti‐inflammatory (NSAIDs) COX‐2 inhibitors and PUFAs. PUFAs such as AA, EPA, and DHA inhibited PMPMEase activity with Ki values of 0.12–3.7 µM. The most potent prostaglandin was 63‐fold less potent than AA. The PUFAs were also more effective at inducing neuroblastoma cell death at physiologically equivalent concentrations. The lost PMPMEase activity in AA‐treated degenerating cells was restored by incubating the lysates with COX‐1 or COX‐2. PUFAs may thus be physiological regulators of cell growth and could owe these effects to PMPMEase inhibition.

Practical applications: Some PUFAs have been widely reported to have anticancer benefits. However, the molecular mechanisms for these effects are not well understood. The findings in the current paper appear to suggest that inhibition of PMPMEase may underlie their effects. They also imply that the expression of COX‐2 in various tumors may serve to convert the PUFAs into significantly less inhibitory prostaglandins. From these findings, AA and the other PUFAs, rather than being substrates for the synthesis of tumorigenic agents may actually contribute in suppressing cell proliferation. This being congruent with the lower cancer risks associated with long term use of anti‐inflammatory agents, the practical implications will likely include the nutritional and/or therapeutic management of cancer with the goal of maintaining suitable levels of the fatty acids in tissues.
Optimization of antigorite heat pre‐treatment via kinetic modeling of the dehydroxylation reaction for CO2 mineralization
Authors: Balucan Reydick D. , Kennedy Eric M. , Mackie John F. , Dlugogorski Bogdan Z.
Published: September 2011

This contribution describes a predictive framework expedient to the thermal processing of serpentinites for the mineralization of CO2. We demonstrate the optimization of heat treatment of antigorite, providing a benchmark of an extreme case of activation among serpentine minerals. Antigorite was investigated non‐isothermally via thermogravimetry‐mass spectrometry and in situ X‐ray powder diffraction, its thermal reaction sequence elucidated, and reaction kinetics subsequently modeled. Based on the thermally induced structural changes, preferred content of residual hydroxyls in the dehydroxylated antigorite amounts to 10–40% of those present initially. This degree of dehydroxylation minimized the transformation of antigorite into new crystalline phases maximizing the amorphization of the new structure. The thermal reaction sequence provided both the explanation for the observed kinetic behavior and the basis for this optimization strategy. The optimal time for heat activation corresponds to ≤30 min, including the heat‐up period at a rate of 30 °C min–1 and an isothermal stage at 730 °C. This was successfully modeled using a three‐dimensional phase boundary reaction model (R3), with activation energy Ea of 160 kJ mol–1 and a frequency factor A of 5.7 ± 4.1 × 105 s–1 (5.7 × 105 s–1 for dynamic and 1.6 × 105 s–1 for static stage). This strategy translates to a fast and efficient thermal processing in an optimally sized calcining vessel. Furthermore, these results imply that activation of the more common serpentine minerals lizardite and chrysotile would be significantly faster as their dehydroxylation proceeds at lower temperatures than that of antigorite. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Ammonium salt‐based steelmaking slag carbonation: Precipitation of CaCO3 and ammonia losses assessment
Authors: Eloneva Sanni , Mannisto Pekka , Said Arshe , Fogelholm Carl‐Johan , Zevenhoven Ron
Published: September 2011

A mineral carbonation method based on steelmaking slags and ammonium salt solutions has been found to have economical and CO2 emission reduction potential. Although the aqueous solution of ammonium salt can be recycled, some of the solvent is likely to escape in a form of ammonia vapor within the outgoing gas flow during the carbonation step. In this study, the escape of ammonia vapor was investigated. The loss of NH3 was found to be quite insignificant and in addition, the total solution loss per step was very small. The CO2 content of the ingoing gas flow affected the rate of the CaCO3 precipitation; the smaller the CO2 content, the longer the duration of the carbonation reaction. However, the CO2 content did not seem to have a significant effect on the degree of CaCO3 precipitation, indicating that CO2 capture in a separate process step should not be needed. CaCO3 precipitated in a form of calcite, although two of the precipitates also contained aragonite. Furthermore, the precipitates were found to be of high quality with bright white color, and fine and powdery texture. Nonetheless, in order to obtain high‐quality CaCO3, the precipitate resulting from the carbonation step should be washed with an adequate amount of water. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Muscarinic receptor activation enables persistent firing in pyramidal neurons from superficial layers of dorsal perirhinal cortex
Authors: Navaroli Vicky L. , Zhao Yanjun , Boguszewski Pawel , Brown Thomas H.
Published: September 2011

Persistent‐firing neurons in the entorhinal cortex (EC) and the lateral nucleus of the amygdala (LA) continue to discharge long after the termination of the original, spike‐initiating current. An emerging theory proposes that endogenous persistent firing helps support a transient memory system. This study demonstrated that persistent‐firing neurons are also prevalent in rat perirhinal cortex (PR), which lies immediately adjacent to and is reciprocally connected with EC and LA. Several characteristics of persistent‐firing neurons in PR were similar to those previously reported in LA and EC. Persistent firing in PR was enabled by the application of carbachol, a nonselective cholinergic agonist, and it was induced by injecting a suprathreshold current or by stimulating suprathreshold excitatory synaptic inputs to the neuron. Once induced, persistent firing lasted for seconds to minutes. Persistent firing could always be terminated by a sufficiently large and prolonged hyperpolarizing current; it was prevented by antagonists of muscarinic cholinergic receptors (mAChRs); and it was blocked by flufenamic acid. The latter has been suggested to inhibit a Ca2+‐activated nonspecific cation conductance (GCAN) that normally furnishes the sustained depolarization during persistent firing. In many PR neurons, the discharge rate during persistent firing was a graded function of depolarizing and/or hyperpolarizing inputs. Persistent firing was not prevented by blocking fast excitatory and inhibitory synaptic transmission, demonstrating that it can be generated endogenously. We suggest that persistent‐firing neurons in PR, EC, LA, and certain other brain regions may cooperate in support of a transient‐memory system. © 2011 Wiley Periodicals, Inc.
Integration managers' value‐capturing roles and acquisition performance
Authors: Teerikangas Satu , Véry Philippe , Pisano Vincenzo
Published: September 2011

Although the significance of managing the acquisition process is acknowledged, little evidence exists as to the ways in which managerial action throughout this process impacts acquisition performance. In this article, the researchers draw attention to the central, yet largely neglected figure responsible for implementing mergers and acquisitions (M&A), namely “the integration manager.” Drawing from an extensive study of nine related, friendly acquisitions involving 166 interviews, the authors find that integration managers affect acquisition performance by capturing value derived from (a) the preacquisition phase, (b) the acquiring firm, and (c) the acquired firm. Through their in/;action, integration managers affect two sources of economic performance: the extent of additional value created and the extent of value leaked. The findings contribute to enriching our knowledge of managing the acquisition process and are a call for more actor‐based, micro‐level studies on the ways in which managing the acquisition process and the actors therein affect acquisition performance. © 2011 Wiley Periodicals, Inc
Lysophosphatidic acid receptor 2/3‐mediated IL‐8‐dependent angiogenesis in cervical cancer cells
Authors: Chen Ruey‐Jien , Chen Shee‐Uan , Chou Chia‐Hung , Lin Ming‐Chieh
Published: September 2011

The expression of lysophosphatidic acid (LPA)‐specific receptors in cervical cancer has not been clearly defined. In this study, we identified LPA1, LPA2 and LPA3 receptors' mRNA in SiHa, HeLa and CaSki cell lines by RT‐PCR. These receptors were not associated with tumor cell proliferation in vitro. We then used a xenograph animal model to evaluate the effects of these receptors on in vivo cervical cancer tumorigenicity. When SiHa cells with different receptor expression patterns were seeded on the backs of SCID mice, the resulting knockout of both LPA2 and LPA3 significantly attenuated tumor growth; this decrease in tumor growth was found to be linked with decreased angiogenesis (microvessel density), suggesting that LPA2 and LPA3 are crucial for in vivo tumor growth through an angiogenic mechanism. We further investigated this mechanism of LPA receptor 2/3‐mediated angiogenic capability by analyzing angiogenic factors in protein lysates from receptor knockout tumors, by detecting interleukin (IL‐8) mRNA expression after treating with siRNA, by evaluating the biological role of LPA‐enhanced IL‐8 via endothelial cell tube formation, monolayer permeability, migration and cell growth assays, and by IL‐8 knockout xenograft mice modeling. We found that the angiogenesis is mediated through IL‐8. Finally, we evaluated the regulation pathways involved in LPA‐induced IL‐8 expression. We found that LPA receptor 2/3‐mediated IL‐8 expression occurs through Gi/PI3K/AKT, Gi/PKC and IκB/NF‐κB signaling. In conclusion, we propose that LPA2 and LPA3 might play an important role in cervical cancer tumor growth through IL‐8‐dependent angiogenesis.
Split Inteins: Nature’s Protein Ligases
Authors: Shah Neel H. , Muir Tom W.
Published: September 2011

Split inteins carry out a naturally occurring process known as protein trans‐splicing, where two protein fragments bind to form a catalytically competent enzyme, then catalyze their own excision and the ligation of their flanking sequences. In the past thirteen years since their discovery, chemists and biologists have utilized split inteins in exogenous contexts for a number of biotechnological applications centered around the formation of native peptide bonds. While many protein trans‐splicing technologies have emerged and flourished in recent years, several factors still limit their wide‐spread practical use. Here, we discuss the development, applications, and limitations of split intein‐based technologies and propose that further advancement in this field will require a more fundamental understanding of split intein structure and function.
Biomaterial testing for covered stent membranes: Evaluating thrombosis and restenosis potential
Authors: Weaver Jason D. , Ku David N.
Published: September 2011

Covered stents may be able to prevent both thrombosis and restenosis, but new mechanically suitable and biocompatible materials are needed before this treatment option can become a reality. Hydrophilic polyvinyl alcohol (PVA) cryogels have desirable mechanical properties for covered stent membranes and may be able to provide a physical barrier to restenosis with low thrombogenicity. An in vitro flow loop with porcine blood was used to compare thrombus formation on different blood‐contacting biomaterials. PVA cryogels were found to maintain blood flow with low thrombogenicity and were significantly less thrombogenic than polyester (p < 0.05). The ability to prevent hyperplasic in‐growth was evaluated using a modified Boyden chamber cellular migration assay. PVA cryogel membranes used as a physical barrier were found to nearly eliminate cellular migration (p < 0.05) without cellular toxicity. Overall, this article demonstrates pivotal feasibility results for a covered stent membrane material that could prevent restenosis by means of a hydrogel barrier with low thrombogenicity. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Longitudinal evaluation of FGF23 changes and mineral metabolism abnormalities in a mouse model of chronic kidney disease
Authors: Stubbs Jason R , He Nan , Idiculla Arun , Gillihan Ryan , Liu Shiguang , David Valentin , Hong Yan , Quarles L Darryl
Published: September 2011

Fibroblast growth factor 23 (FGF23) is a phosphaturic and vitamin D-regulatory hormone of putative bone origin that is elevated in patients with chronic kidney disease (CKD). The mechanisms responsible for elevations of FGF23 and its role in the pathogenesis of chronic kidney disease-mineral bone disorder (CKD-MBD) remain uncertain. We investigated the association between FGF23 serum levels and kidney disease progression, as well as the phenotypic features of CKD-MBD in a Col4a3 null mouse model of human autosomal-recessive Alport syndrome. These mice exhibited progressive renal failure, declining 1,25(OH)2D levels, increments in parathyroid hormone (PTH) and FGF23, late-onset hypocalcemia and hyperphosphatemia, high-turnover bone disease, and increased mortality. Serum levels of FGF23 increased in the earliest stages of renal damage, before elevations in blood urea nitrogen (BUN) and creatinine. FGF23 gene transcription in bone, however, did not increase until late-stage kidney disease, when serum FGF23 levels were exponentially elevated. Further evaluation of bone revealed trabecular osteocytes to be the primary cell source for FGF23 production in late-stage disease. Changes in FGF23 mirrored the rise in serum PTH and the decline in circulating 1,25(OH)2D. The rise in PTH and FGF23 in Col4a3 null mice coincided with an increase in the urinary fractional excretion of phosphorus and a progressive decline in sodium-phosphate cotransporter gene expression in the kidney. Our findings suggest elevations of FGF23 in CKD to be an early marker of renal injury that increases before BUN and serum creatinine. An increased production of FGF23 by bone may not be responsible for early increments in FGF23 in CKD but does appear to contribute to FGF23 levels in late-stage disease. Elevations in FGF23 and PTH coincide with an increase in urinary phosphate excretion that likely prevents the early onset of hyperphosphatemia in the face of increased bone turnover and a progressive decline in functional renal mass. © 2012 American Society for Bone and Mineral Research
Oxygen versus sulfur: Structure and reactivity of substituted arsine oxides and arsine sulfides
Authors: Orthaber Andreas , Sax Alexander F. , Francesconi Kevin A.
Published: September 2011

Although arsenic in its inorganic forms is a well know toxic agent, biotransformations in the environment and in the human body can produce organoarsenic compounds that are generally of much lower toxicity. Foremost among these products is a range of dimethylated arsine oxides and their analogous sulfides, which are crucial to the arsenic detoxification process. We have investigated the formation and interconversion of substituted and unsubstituted arsenicals (R22As(Z)R1, R2 = CH3, R1 = CH2CH2OH, CH2COOH; Z = S or O) with density functional theory (DFT)/B3LYP. Formation of isomers including a cyclic hydrogen bonded conformer is observed for the ethanol and acetate derivatives. Furthermore, investigating the reaction of arsine oxide with hydrogen sulfide revealed the formation of arsine sulfide via pentacoordinated trigonal bipyramidal intermediates. A tetragonal pyramidal transition state was located enabling exchange of equatorial and axial positions in the trigonal bipyramidal species. The reaction was proven exothermic for all studied substituents (ΔErxn −50 to −80 kJ/mol). This fundamental study shows that H2S easily leads to the formation of thio‐organoarsenicals. Conversion of arsine sulfides into their corresponding arsine oxides is experimentally accomplished with hydrogen peroxide, which could also be rationalized by means of ab initio calculations showing high exothermicity (ΔErxnca. −550 kJ/mol). Reactions are considered at different levels of theory (i.e., DFT, second and fourth order Møller–Plesset (MP) perturbation theory) including two solvation models for DFT, which show good agreement for resulting geometries and reaction energies. Hence, the widely used B3LYP/6‐31G** combination is a suitable method for the description of molecular organoarsenicals. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Sonographic diagnosis of a posttraumatic arteriocavernosal fistula resulting in high‐flow priapism
Authors: Keck Bastian , Lotter Gabriele , Wieland Wolf Ferdinand , Wullich Bernd , Uder Michael , Engehausen Dirk Gehrhard , Fritsche Hans Martin
Published: September 2011

We present a case of high‐flow priapism due to perineal trauma and subsequent arteriocavernosal fistula, which was diagnosed by sonography. Selective arterial embolization led to complete detumescence without compromising the patient's erectile function. Color Doppler sonography is an appropriate diagnostic tool to diagnose arteriocavernosal fistula. Selective arterial embolization is a safe and effective therapeutic option. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound, 2011;
Invasive implantation and intimate placental associations in a placentotrophic african lizard, Trachylepis ivensi (scincidae)
Authors: Blackburn Daniel G. , Flemming Alexander F.
Published: September 2011

In the viviparous lizard Trachylepis ivensi (Scincidae) of central Africa, reproducing females ovulate tiny ∼1 mm eggs and supply the nutrients for development by placental means. Histological study shows that this species has evolved an extraordinary placental pattern long thought to be confined to mammals, in which fetal tissues invade the uterine lining to contact maternal blood vessels. The vestigial shell membrane disappears very early in development, allowing the egg to absorb uterine secretions. The yolk is enveloped precocially by the trilaminar yolk sac and no isolated yolk mass or yolk cleft develops. Early placentas are formed from the chorion and choriovitelline membranes during the neurula through pharyngula stages. During implantation, cells of the chorionic ectoderm penetrate between uterine epithelial cells. The penetrating tissue undergoes hypertrophy and hyperplasia, giving rise to sheets of epithelial tissue that invade beneath the uterine epithelium, stripping it away. As a result, fetal epithelium entirely replaces the uterine epithelium, and lies in direct contact with maternal capillaries and connective tissue. Placentation is endotheliochorial and fundamentally different from that of all other viviparous reptiles known. Further, the pattern of fetal membrane development (with successive loss and re‐establishment of an extensive choriovitelline membrane) is unique among vertebrates. T. ivensi represents a new extreme in placental specializations of reptiles, and is the most striking case of convergence on the developmental features of viviparous mammals known. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc.
Spermatophoric reaction reappraised: Novel insights into the functioning of the loliginid spermatophore based on Doryteuthis plei (Mollusca: Cephalopoda)
Authors: Marian José Eduardo A.R.
Published: September 2011

During copulation, spermatophores produced by male coleoid cephalopods undergo the spermatophoric reaction, a complex process of evagination that culminates in the attachment of the spermatangium (everted spermatophore containing the sperm mass) on the female's body. To better understand this complicated phenomenon, the present study investigated the functional morphology of the spermatophore of the squid Doryteuthis plei applying in vitro analysis of the reaction, as well as light and electron microscopy investigation of spermatangia obtained either in vitro, or naturally attached on females. Hitherto unnoticed functional features of the loliginid spermatophore require a reappraisal of some important processes involved in the spermatophoric reaction. The most striking findings concern the attachment mechanism, which is not carried out solely by cement adhesive material, as previously believed, but rather by an autonomous, complex process performed by multiple structures during the spermatophoric reaction. During evagination, the ejaculatory apparatus provides anchorage on the targeted tissue, presumably due to the minute stellate particles present in the exposed spiral filament. Consequently, the ejaculatory apparatus maintains the attachment of the tip of the evaginating spermatophore until the cement body is extruded. Subsequently, the cement body passes through a complex structural rearrangement, which leads to the injection of both its viscid contents and pointed oral region onto the targeted tissue. The inner membrane at the oral region of the cement body contains numerous stellate particles attached at its inner side; eversion of this membrane exposes these sharp structures, which presumably adhere to the tissue and augment attachment. Several naturally attached spermatangia were found with their bases implanted at the deposition sites, and the possible mechanisms of perforation are discussed based on present evidence. The function of the complex squid spermatophore and its spermatophoric reaction is revisited in light of these findings. J. Morphol. 2012. © 2011 Wiley Periodicals, Inc.
In vivo MR quantification of superparamagnetic iron oxide nanoparticle leakage during low‐frequency‐ultrasound‐induced blood–brain barrier opening in swine
Authors: Liu Hao‐Li , Chen Pin‐Yuan , Yang Hung‐Wei , Wu Jia‐Shin , Tseng I‐Chou , Ma Yan‐Jung , Huang Chih‐Ying , Tsai Hong‐Chieh , Chen Shu‐Mei , Lu Yu‐Jen , Huang Chiung‐Yin , Hua Mu‐Yi , Ma Yunn‐Hwa , Yen Tzu‐Chen , Wei Kuo‐Chen
Published: September 2011

Purpose:

To verify that low‐frequency planar ultrasound can be used to disrupt the BBB in large animals, and the usefulness of MRI to quantitatively monitor the delivery of superparamagnetic iron oxide (SPIO) nanoparticles into the disrupted regions.

Materials and Methods:

Two groups of swine subjected to craniotomy were sonicated with burst lengths of 30 or 100 ms, and one group of experiment was also performed to confirm the ability of 28‐kHz sonication to open the BBB transcranially. SPIO nanoparticles were administered to the animals after BBB disruption. Procedures were monitored by MRI; SPIO concentrations were estimated by relaxivity mapping.

Results:

Sonication for 30 ms created shallow disruptions near the probe tip; 100‐ms sonications after craniotomy can create larger and more penetrating openings, increasing SPIO leakage ∼3.6‐fold than 30‐ms sonications. However, this was accompanied by off‐target effects possibly caused by ultrasonic wave reflection. SPIO concentrations estimated from transverse relaxation rate maps correlated well with direct measurements of SPIO concentration by optical emission spectrometry. We have also shown that transcranial low‐frequency 28‐kHz sonication can induce secure BBB opening from longitudinal MR image follow up to 7 days.

Conclusion:

This study provides valuable information regarding the use low‐frequency ultrasound for BBB disruption and suggest that SPIO nanoparticles has the potential to serve as a thernostic agent in MRI‐guided ultrasound‐enhanced brain drug delivery. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
Correspondence of human visual areas identified using functional and anatomical MRI in vivo at 7 T
Authors: Sánchez‐Panchuelo Rosa M. , Francis Susan T. , Schluppeck Denis , Bowtell Richard W.
Published: September 2011

Purpose:

To study the correspondence of anatomically and functionally defined visual areas (primary visual cortex, V1, and motion selective area V5/human MT+) by using structural magnetic resonance imaging (MRI) and functional MRI (fMRI) in vivo at 7 T.

Materials and Methods:

Four subjects participated in this study. High‐resolution (≈0.4 mm isotropic) anatomical MRI was used to identify cortical regions based on their distinct cortical lamination. The optimal contrast for identifying heavily myelinated layers within gray matter was quantitatively assessed by comparing T1‐weighted magnetization‐prepared rapid gradient echo (MPRAGE) and T2*‐weighted, 3D fast‐low angle shot (FLASH) imaging. Retinotopic mapping was performed using GE‐based fMRI at 1.5 mm isotropic resolution to identify functional areas.

Results:

T2*‐weighted FLASH imaging was found to provide a significantly higher contrast‐to‐noise ratio, allowing visualization of the stria of Gennari in every slice of a volume covering the occipital cortex in each of the four subjects in this study. The independently derived boundary of V1, identified in the same subjects using retinotopic mapping by fMRI, closely matched the border of anatomically defined striate cortex in the human brain. Evidence of banding was also found within the functionally defined V5 area; however, we did not find a good correlation of this area, or the functionally identified subregion (MT), with the banded area.

Conclusion:

High‐resolution T2*‐weighted images acquired at 7 T can be used to identify myelinated bands within cortical gray matter in reasonable measurement times. Regions where a myelinated band was identified show a high degree of overlap with the functionally defined V1 area. J. Magn. Reson. Imaging 2012;287‐299. © 2011 Wiley Periodicals, Inc.
Perisynaptic aggrecan‐based extracellular matrix coats in the human lateral geniculate body devoid of perineuronal nets
Authors: Lendvai D. , Morawski M. , Brückner G. , Négyessy L. , Baksa G. , Glasz T. , Patonay L. , Matthews R.T. , Arendt T. , Alpár A.
Published: September 2011

The extracellular matrix surrounds different neuronal compartments in the mature nervous system. In a variety of vertebrates, most brain regions are loaded with a distinct type of extracellular matrix around the somatodendritic part of neurons, termed perineuronal nets. The present study reports that chondrotin sulfate proteoglycan‐based matrix is structured differently in the human lateral geniculate body. Using various chondrotin sulfate proteoglycan‐based extracellular matrix antibodies, we show that perisomatic matrix labeling is rather weak or absent, whereas dendrites are contacted by axonal coats appearing as small, oval structures. Confocal laser scanning microscopy and electron microscopy demonstrated that these typical structures are associated with synaptic loci on dendrites. Using multiple labelings, we show that different chondrotin sulfate proteoglycan components of the extracellular matrix do not associate exclusively with neuronal structures but possibly associate with glial structures as well. Finally, we confirm and extend previous findings in primates that intensity differences of various extracellular matrix markers between magno‐ and parvocellular layers reflect functional segregation between these layers in the human lateral geniculate body. © 2011 Wiley Periodicals, Inc.
Neuroprotection by hypoxic preconditioning involves upregulation of hypoxia‐inducible factor‐1 in a prenatal model of acute hypoxia
Authors: Giusti Sebastián , Fiszer de Plazas Sara
Published: September 2011

The molecular pathways underlying the neuroprotective effects of preconditioning are promising, potentially drugable targets to promote cell survival. However, these pathways are complex and are not yet fully understood. In this study we have established a paradigm of hypoxic preconditioning based on a chick embryo model of normobaric acute hypoxia previously developed by our group. With this model, we analyzed the role of hypoxia‐inducible factor‐1α (HIF‐1α) stabilization during preconditioning in HIF‐1 signaling after the hypoxic injury and in the development of a neuroprotective effect against the insult. To this end, we used a pharmacological approach, based on the in vivo administration of positive (Fe2+, ascorbate) and negative (CoCl2) modulators of the activity of HIF‐prolyl hydroxylases (PHDs), the main regulators of HIF‐1. We have found that preconditioning has a reinforcing effect on HIF‐1 accumulation during the subsequent hypoxic injury. In addition, we have also demonstrated that HIF‐1 induction during hypoxic preconditioning is necessary to obtain an enhancement in HIF‐1 accumulation and to develop a tolerance against a subsequent hypoxic injury. We provide in vivo evidence that administration of Fe2+ and ascorbate modulates HIF accumulation, suggesting that PHDs might be targets for neuroprotection in the CNS. © 2011 Wiley Periodicals, Inc.
Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin
Authors: Izquierdo‐Román Alondra , Vogt William C. , Hyacinth Leeanna , Rylander Christopher G.
Published: September 2011

Background and Objectives

Mechanical tissue optical clearing permits light delivery deeper into turbid tissue, which may improve current optical diagnostics and laser‐based therapeutic techniques. We investigated the effects of localized compression on brightfield imaging through ex vivo porcine skin by evaluating resolution and contrast of a target positioned beneath native, mechanically compressed, or chemically cleared specimens. We also evaluated the effects of indentation on dynamic tissue thickness and light transmission.

Study Design/Methods

A 5 mm diameter, hemispherically tipped, manual load transducer was used to compress specimens using 2–44 N for 60 seconds. Chemically cleared specimens were immersed for 1 hour in glycerol or dimethyl sulfoxide. A USAF 1951 resolution target was positioned beneath specimens and imaged using brightfield microscopy. Resolution and contrast of target features were analyzed. In separate experiments, a mechanical test instrument was used to compress and hold specimens at a final thickness while measuring applied load and light transmission.

Results

Image intensity profiles showed that while uncompressed skin did not allow resolution of any target, localized compression allowed maximum resolution up to a line width of 173 ± 21 µm. Mechanical clearing achieved up to four times higher maximum resolution and 2–3 times higher contrast sensitivity than chemical immersion. Resolving capability was highly correlated with compressive tissue strain. Light transmission increased during tissue compression, but also increased while holding final thickness constant.

Conclusion

Localized compression is an effective technique for increasing resolution and contrast of target features through tissue and may improve light‐based diagnostics. Thickness reduction and other mechanisms appear to contribute to this effect. Lasers Surg. Med. © 2011 Wiley‐Liss, Inc.
An efficient finite–discrete element method for quasi‐static nonlinear soil–structure interaction problems
Authors: Dang Hoang K. , Meguid Mohamed A.
Published: September 2011

An efficient finite–discrete element method applicable for the analysis of quasi‐static nonlinear soil–structure interaction problems involving large deformations in three‐dimensional space was presented in this paper. The present method differs from previous approaches in that the use of very fine mesh and small time steps was not needed to stabilize the calculation. The domain involving the large displacement was modeled using discrete elements, whereas the rest of the domain was modeled using finite elements. Forces acting on the discrete and finite elements were related by introducing interface elements at the boundary of the two domains. To improve the stability of the developed method, we used explicit time integration with different damping schemes applied to each domain to relax the system and to reach stability condition. With appropriate damping schemes, a relatively coarse finite element mesh can be used, resulting in significant savings in the computation time. The proposed algorithm was validated using three different benchmark problems, and the numerical results were compared with existing analytical and numerical solutions. The algorithm performance in solving practical soil–structure interaction problems was also investigated by simulating a large‐scale soft ground tunneling problem involving soil loss near an existing lining. Copyright © 2011 John Wiley & Sons, Ltd.
Column generation algorithm for sensor coverage scheduling under bandwidth constraints
Authors: Rossi André , Singh Alok , Sevaux Marc
Published: September 2011

This article addresses three problems that arise in coverage scheduling for wireless sensor networks subject to bandwidth constraints. The first problem focuses on minimizing the total breach under a lifetime constraint, where a breach occurs when some targets are not covered by active sensors. The second problem aims at maximizing the network lifetime under a breach constraint. Finally, the problem of computing the possible trade‐offs between breach and lifetime offered by the sensor network is also addressed. An exact approach based on a column generation algorithm is proposed for solving these problems, and a heuristic is also derived from it and briefly presented. The use of a genetic algorithm within the column generation scheme appears to significantly decrease computation time. © 2011 Wiley Periodicals, Inc. NETWORKS, 2012
THE INFLUENCE OF E‐GOVERNMENT ON ADMINISTRATIVE DISCRETION: THE CASE OF LOCAL GOVERNMENTS IN EGYPT
Authors: Reddick Christopher G. , Abdelsalam Hisham M. , Elkadi Hatem
Published: September 2011

One important but often understudied area of research in public administration is the effect of e‐government on administrative discretion. This article examines e‐government factors that influence administrative discretion through a survey of local governments. The focus of this study is on Egyptian local governments, which are using e‐government to modernise public service delivery. Through a survey of administrative officials in these governments, this study found evidence that e‐government factors of collaboration and organisational change influenced administrative discretion. Other common factors noted in the literature such as size of the local government and demand by citizens for e‐government did not register an effect on administrative discretion. The results of this study imply that local governments should do more to enhance e‐government to reduce administrative discretion, especially in the area of increasing collaboration. Copyright © 2011 John Wiley & Sons, Ltd.
Primary cilia and coordination of receptor tyrosine kinase (RTK) signalling
Authors: Christensen Søren T , Clement Christian A , Satir Peter , Pedersen Lotte B
Published: September 2011

Primary cilia are microtubule‐based sensory organelles that coordinate signalling pathways in cell‐cycle control, migration, differentiation and other cellular processes critical during development and for tissue homeostasis. Accordingly, defects in assembly or function of primary cilia lead to a plethora of developmental disorders and pathological conditions now known as ciliopathies. In this review, we summarize the current status of the role of primary cilia in coordinating receptor tyrosine kinase (RTK) signalling pathways. Further, we present potential mechanisms of signalling crosstalk and networking in the primary cilium and discuss how defects in ciliary RTK signalling are linked to human diseases and disorders. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Enhanced Sample Preparation for Quantitation of Microcystins by Matrix‐Assisted Laser Desorption/Ionisation–Time of Flight Mass Spectrometry
Authors: Puddick Jonathan , Prinsep Michèle R. , Wood Susanna A. , Craig Cary S. , Hamilton David P.
Published: September 2011

Introduction

Microcystins (MCs) are a group of cyanotoxins which pose a serious health threat when present in aquatic systems. Quantitative analysis of MCs by matrix‐assisted laser desorption/ionisation–time of flight (MALDI–TOF) mass spectrometry has potential for the processing of large numbers of samples quickly and economically. The existing method uses an expensive internal standard and protocols that are incompatible with automated sample preparation and data acquisition.

Objective

To produce a MALDI–TOF sample preparation technique for the quantitation of MCs that not only maintains reproducibility and sensitivity, but is also compatible with an automated work‐flow.

Methodology

Seven different MALDI–TOF sample preparations were assessed for signal reproducibility (coefficient of variation) and sensitivity (method detection limit) using a cost‐effective internal standard (angiotensin I). The best preparation was then assessed for its quantitative performance using three different MC congeners ([Dha7] MC‐LR, MC‐RR and MC‐YR).

Results

The sensitivity of six of the preparations was acceptable, as was the reproducibility for two thin‐layer preparations performed on a polished steel target. Both thin‐layer preparations could be used with a MALDI‐TOF mass spectrometer that automatically acquires data, and one could be used in an automated sample preparation work‐flow. Further investigation using the thin‐layer spot preparation demonstrated that linear quantification of three different MC congeners was possible.

Conclusion

The study demonstrates that with different sample preparation methods and modern instrumentation, large numbers of samples can be analysed rapidly for MCs at low cost. Copyright © 2011 John Wiley & Sons, Ltd.
Orientation, mechanical, and optical properties of poly (lactic acid) nanoclay composite films
Authors: Tabatabaei Seyed H. , Ajji Abdellah
Published: September 2011

In this study, the orientation, mechanical as well as the optical properties of multilayer films of nanoclay filled poly (lactic acid) (PLA) as the core layer and polyethylene (PE) as the skin layer obtained from the film blowing process were investigated. The effect of nanoclay content in the range of 1–7.5 wt% was considered. The orientation of the polymers crystal unit cells, alignment of clay platelets as well as the extent of intercalation and exfoliation were studied using wide angle X‐ray diffraction (WAXD). The measurement of d‐spacing of the 001 plane (normal to platelets plane) of the clay tactoids indicated intercalation of the silicate layers in the PLA nanocomposite multilayer films. The Young modulus and tear resistance along the machine and transverse directions (MD and TD, respectively) improved significantly with the presence of the nanoparticles and percentage of nanofiller studied. The haze of the nanocomposite films decreased with clay concentration up to 5 wt% and increased by further addition of the nanoclay. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Properties of PET/clay nanocomposite films
Authors: Ghasemi Hesam , Carreau Pierre J. , Kamal Musa R. , Tabatabaei Seyed H.
Published: September 2011

Polyethylene terephthalate (PET) nanocomposite films were prepared by cast extrusion followed by uniaxial stretching, using chill rolls. Transmission electron microscopy (TEM) and wide angle X‐ray diffraction (WAXD) showed that the clay layers were aligned in the machine direction (MD) in the PET/clay nanocomposite (PCN) films. Differential scanning calorimetry (DSC) showed that PCN films have higher crystallinity than the neat PET films, possibly due to the nucleating role of the silicate layers. The PCN films became hazier as the clay content increased, but the film transparency remained in the acceptable range. Oxygen permeability of the PCN films decreased by 23% compared to the neat PET film. This is comparable with predictions of models proposed in the literature. Silicate incorporation brought about 20% increase in the tensile modulus, while the puncture and tear propagation resistance were reduced, due to brittleness of the PCN films. The measured modulus (1.7 GPa) was somewhat smaller than the values predicted using the Pseudoinclusion model (2.1 GPa). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Are Conservatives Less Likely to be Prosocial than Liberals? From Games to Ideology, Political Preferences and Votingg
Authors: Van Lange Paul A. M. , Bekkers René , Chirumbolo Antonio , Leone Luigi
Published: September 2011

Do political preferences reflect individual differences in interpersonal orientations? Are conservatives less other–regarding than liberals? On the basis of past theorising, we hypothesised that, relative to individuals with prosocial orientations, those with individualistic and competitive orientations should be more likely to endorse conservative political preferences and vote for conservative parties. This hypothesis was supported in three independent studies conducted in Italy (Studies 1 and 2) and the Netherlands (Study 3). Consistent with hypotheses, a cross–sectional study revealed that individualists and competitors endorsed stronger conservative political preferences than did prosocials; moreover, this effect was independent of the association between need for structure and conservative political preferences (Study 1). The predicted association of social value orientation and voting was observed in both a four–week (Study 2) and an eight–month (Study 3) longitudinal study. Taken together, the findings provide novel support for the claim that interpersonal orientations, as measured with experimental games rooted in game theory, are important to understanding differences in ideology at the societal level. Copyright © 2011 John Wiley & Sons, Ltd.
The competencies initiative in American professional psychology: Implications for school psychology preparation
Authors: Daly Edward J. , Doll Beth , Schulte Ann C. , Fenning Pamela
Published: September 2011

In the past decade, American professional psychology has taken significant steps toward a unified statement of the competencies that define the practice of psychology, regardless of specialty. The purpose of this article is to explain the current competency initiative in professional psychology and examine its implications and potential impact on graduate training in school psychology. A brief overview of competency‐based training and the current competencies initiative in psychology is presented. Two significant challenges to implement competency‐based training are then discussed. The first challenge has to do with conceptualizations of training and practice across accreditation agencies. As a part of the discussion, two recently published competency documents from the Assessment of Competencies Benchmark Workgroup of the American Psychological Association and the National Association of School Psychologists are compared in a content analysis. The second challenge discussed is the difficulties associated with operationalizing and measuring competencies. Specifically, the empirical and consequential bases for existing assessment methods are examined. In spite of current pressure by accrediting agencies to implement a competency‐based training model, based on the challenges examined in this article, significant work remains if school psychology trainers want to assure that competency‐based training is done well. © 2011 Wiley Periodicals, Inc.
Polyhedral oligomeric silsesquioxane‐based fluoroether‐containing terpolymers: Synthesis, characterization and their water and oil repellency evaluation for cotton fabric
Authors: Gao Yu , He Chuanglong , Qing Feng‐Ling
Published: September 2011

A series of polyhedral oligomeric silsesquioxane (POSS) based hybrid copolymers poly(POSS‐co‐methyl methacrylate −co‐ 4‐vinylbenzyl fluoroether carboxylate) (P(POSS‐MMA‐VBFC)) were prepared via radical polymerization and characterized by nuclear magnetic resonance, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, X‐ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The thermal properties of these polymers (Td > 250 °C) were improved by the introduction of POSS cage. The cotton fabrics coated with the polymers possessed excellent water and oil repellency. The water and salad oil contact angle could be achieved from 133° to 159° and from 127° to 141° respectively as the content of POSS in the polymer increased from 0 to 7.1 wt %. Moreover, the cotton fabric coated with the terpolymer was less flammable than the uncoated one. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Branched cationic polyurethane prepared by polyaddition of chloromethylated five‐membered cyclic carbonate and diethylenetriamine in molten salts
Authors: Ochiai Bungo , Koda Kazuhiro , Endo Takeshi
Published: September 2011

A branched cationic polymer was synthesized by polyaddition of 4‐chloromethyl‐1,3‐dioxolan‐2‐one and diethylenetriamine in molten salts. The polyaddition proceeded through nucleophilic addition of the primary amino group to the cyclic carbonate structure and quarternization of the secondary amino group with the chloromethyl group. The resulting cationic polymer was a good and recyclable catalyst for the reaction of carbon dioxide and epoxides owing to the ammonium structure. The complexation with DNA was confirmed by dynamic light scattering and zeta potential measurements, and it suggests the potential application as a carrier for drug delivery system. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
(Salan)CrCl, an effective catalyst for the copolymerization and terpolymerization of epoxides and carbon dioxide
Authors: Darensbourg Donald J. , Poland Ross R. , Strickland Amanda L.
Published: September 2011

The selective transformation of CO2 and epoxides to afford completely alternating copolymers remains a topic of much interest for the potential utilization of carbon dioxide in chemical synthesis. The use of salicylaldimine (salen)‐metal complexes and their saturated (salan)‐metal versions have proven to be the most effective and robust single‐site catalyst for these processes. Herein, we report on mechanistic aspects of the copolymerization of alicyclic and aliphatic epoxides with CO2 in toluene solution and in neat epoxides in the presence of a (salan)CrCl/onium salt catalyst system. The activation barriers for both cyclohexene oxide(CHO)/CO2 and propylene oxide(PO)/CO2 were shown to be significantly higher in toluene solution than those previously reported for reactions carried out under solventless conditions. Terpolymerization of CHO/vinylcyclohexene oxide/CO2 was shown via Fineman‐Ross analysis at 60 °C to proceed with little monomer selectivity, for example, rCHO = 1.03 and rVCHO = 0.847. On the other hand, terpolymerization of CHO/PO/CO2 occurred at 25 °C with a propensity for incorporation of PO in the polymer. However, at 40 °C, Fineman‐Ross analysis revealed rCHO and rPO values of 0.869 and 1.49, thereby affording a terpolymer with a more equal distribution of monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012