bluuebunny/crossref_metadata_2025 huggingface dataset:
Miniemulsion copolymerizations of styrene and reactive alkyl methacrylate costabilizers
Authors: Kusdianto C.T. Lin , Yu F.E. , Chern C.S.
Published: July 2010

Miniemulsion copolymerizations of styrene (ST) and stearyl methacrylate (SMA) or lauryl methacrylate (LMA) were investigated. Miniemulsions comprising ST and various levels of SMA showed very good storage stability against the diffusional degradation of monomer droplets (Ostwald ripening), whereas miniemulsions comprising ST and various levels of LMA exhibited significant Ostwald ripening. In subsequent miniemulsion copolymerizations of ST and SMA, particle nucleation occurring in the continuous aqueous phase (homogeneous nucleation) plays an important role in the particle formation process in addition to monomer droplet nucleation. The final overall conversion and the individual conversions of ST and SMA all decrease with increasing SMA concentration. Furthermore, at a particular reaction time, the individual conversion of SMA is always greater than that of ST. Monomer droplet nucleation was retarded severely for the monomer pair ST/LMA, presumably due to the very strong Ostwald ripening effect. As a result, relatively slow rates of copolymerization of ST and LMA were attained compared with the ST/SMA counterpart. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Detection of low levels of long‐chain branching in polydisperse polyethylene materials
Authors: Karjala Teresa P. , Sammler Robert L. , Mangnus Marc A. , Hazlitt Lonnie G. , Johnson Mark S. , Wang Jian , Hagen Charles M. , Huang Joseph W. L. , Reichek Kenneth N.
Published: July 2010

Creep experiments have been applied to probe the zero‐shear viscosity, η0, of polyethylene chains directly and precisely in a constant‐stress rheometer at 190°C. Such experiments, when combined with precise measurements of the weight‐average molecular weight,Mw, calibrated relative to linear chains of high‐density polyethylene, are shown to provide a very sensitive approach to detect low levels (0.005 branches per 1000 carbons) of long‐chain branching (LCB). This detection limit is shown to be insensitive to whether the molecular weight distribution (MWD) breadth,Mw/Mn, rises from about two to ten. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Tailoring the polymeric nanoparticles for rubber reinforcement
Authors: Lin Chenchy J. , Wang Xiaorong
Published: July 2010

Polymeric nanoparticles with brush‐like polydiene as the shell and crosslinked polystyrene as the core are synthesized using anionic polymerization via a self‐assembly process of macromolecules in solutions. The microstructures of nanoparticles were designed to match those of the matrix polymer used for tire compounds. Desirable compound properties were obtained by tailoring the shell sizes of the nanoparticles. Depending on the core/shell structures of the nanopartilces, the addition of the nanosized particles may impart the compound ultimate physical properties. Well reinforced compounds with enhanced dynamical storage modulus (G′) without increasing their dependences on temperature and deformation strain can be obtained by the addition of the nanoparticle with lengthened shell chains. Improved tensile mechanical properties without increasing high‐temperature hysteresis were also attained by such reinforcement. Passenger and truck tire applications can be advantageously benefited from these properties with improved tire handling and cornering consistence without increasing the rolling resistance and the sacrifices of other performances. A miscibility study was conducted on various binary blends of nanoparticle and rubber matrix. The compatibility between the nanoparticle and the matrix rubber along with the core concentration were demonstrated to be responsible for the observed improved compound properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Poly(amidoamine) dendritic structures, bearing different end groups, as adhesion promoters for urea–formaldehyde wood adhesive system
Authors: Essawy Hisham A. , Mohamed Heba A.
Published: July 2010

A series of core‐shell poly(amidoamine) (PAMAM) dendritic compounds bearing different end groups such as OH, NH2, and NH3+−Cl up to the third generation were prepared via successive Michael addition of a nucleophilic core (ethylenediamine) to methylacrylate followed by amination steps using ethylenediamine for the amine‐terminated while ethanolamine for the hydroxyl‐terminated compounds, also the protonated ammonium salt terminated form was obtained by cationization of the amine‐terminated form using hydrochloric acid solution. The Surface activity and aggregation behavior of the corresponding aqueous solutions of the prepared generations with their different end groups were studied and confirmed by surface tension measurements using ring method technique. The prepared dendrimers showed high surface activity and the measurements revealed their ability to self aggregate in water at very low concentrations, critical aggregation concentrations (CACs). The CACs were found to decrease with increasing the generation number, which implies that molecular weight and structure play important rules in controlling the surface activity and CAC. The dendritic compounds proved to be effective as adhesion promoters for urea formaldehyde (UF) resins when applied as wood adhesive systems, which was ascribed in partial to the improved wetting over the substrate, a role that is fundamentally related to the huge number of function groups present at the interface. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Enhanced transdermal delivery of 5‐aminolevulinic acid and a dipeptide by iontophoresis
Authors: Krishnan Gayathri , Roberts Michael S. , Grice Jeffrey , Anissimov Yuri G. , Benson Heather A. E.
Published: July 2010

Poor skin permeability limits the application of peptides to the skin. Enhanced skin permeation could facilitate the development of new therapies for dermatologic and cosmeceutical applications. The aim of this study was to investigate the application of iontophoresis to the delivery of small peptide model compounds (5‐aminolevulinic acid andL‐alanine‐L‐tryptophan) across human skin. Under the conditions tested, iontophoresis increased the in vitro permeability coefficient of ALA.HCl across human epidermis from 7 × 10−5cm/h with passive diffusion to 110 × 10−5cm/h with iontophoresis.D‐Glucose permeation elucidated the iontophoretic electrotransport of ALA.HCl to have contributions of both electrorepulsion and electroosmosis. TheL‐alanine‐L‐tryptophan permeability coefficient was increased from 1.5 × 10−5cm/h to 35 × 10−5cm/h with iontophoretic application. Iontophoretic delivery of the dipeptide increased markedly at lower pH because of an increase in electrorepulsive transport. The study demonstrates that iontophoresis can enhance epidermal permeation of a small peptide and peptide‐like drug by up to 15‐ and 22‐fold under the conditions tested. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 166–171, 2011.
Novel 3‐Carboxy‐ and 3‐Phosphonopyrazoline Amino Acids as Potent and Selective NMDA Receptor Antagonists: Design, Synthesis, and Pharmacological Characterization
Authors: Conti Paola , Pinto Andrea , Tamborini Lucia , Madsen Ulf , Nielsen Birgitte , Bräuner‐Osborne Hans , Hansen Kasper B. , Landucci Elisa , Pellegrini‐Giampietro Domenico E. , De Sarro Giovambattista , Donato Di Paola Eugenio , De Micheli Carlo
Published: July 2010

The design and synthesis of new N1‐substituted 3‐carboxy‐ and 3‐phosphonopyrazoline and pyrazole amino acids that target the glutamate binding site of NMDA receptors are described. An analysis of the stereochemical requirements for high‐affinity interaction with these receptors was performed. We identified two highly potent and selective competitive NMDA receptor antagonists, (5S,αR)‐1and (5S,αR)‐4, which exhibit good in vitro neuroprotective activity and in vivo anticonvulsant activity by i.p. administration, suggesting that these molecules may have potential use as therapeutic agents.
Characterization of ZnO nanorods grown on Si substrates coated with NiCl2
Authors: Wang Jie , Zhuang Huizhao , Li Junlin , Xu Peng
Published: July 2010

ZnO nanorods were synthesized on NiCl2‐coated Si substrates via a chemical vapor deposition (CVD) process. The as‐fabricated nanorods with diameters ranging from 150 nm to 200 nm and lengths up to several tens of micrometers grew preferentially arranged along [0001] direction, perpendicular to the (0002) plane. The clear lattice fringes in HRTEM image demonstrated the growth of good quality hexagonal single‐crystalline ZnO. Room temperature photoluminescence (PL) spectra illustrated that the ZnO nanorods exhibit strong UV emission peak and green emission peak, peak centers located at 388 nm and 506 nm. A possible growth mechanism based on the study of our X‐ray diffraction (XRD), electron microscopy and PL spectroscopy was proposed, emphasizing the effect of NiCl2 solution (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stent migration to the ileum—A potentially lethal complication after montgomery salivary bypass tube placement for hypopharyngeal stenosis after laryngectomy
Authors: Bitter Thomas , Pantel Mira , Dittmar Yves , Guntinas‐Lichius Orlando , Wittekindt Claus
Published: July 2010

Background

Montgomery salivary bypass tubes (MSBTs) have been used for decades in the treatment of stenoses and fistulae of the hypopharynx and the cervical esophagus. Generally, MSBT use is not associated with serious complications. Only a small number of cases with severe MSBT‐associated complications have been reported in the literature.

Methods and Results

We report for the first time an MSBT migration to the ileum in a laryngectomized patient who underwent surgical pharyngocutaneous fistula closure with MSBT placement. The MSBT was removed surgically via laparotomy. The patient died 15 days later due to sepsis associated with peritonitis.

Conclusion

To avoid potentially lethal complications associated with MSBT migration into the intestinal tract, we recommend secure fixation of the MSBT to a nasogastric tube. © 2010 Wiley Periodicals, Inc. Head Neck, 2012
Correlation of the expression of human kallikrein‐related peptidases 4 and 7 with the prognosis in oral squamous cell carcinoma
Authors: Zhao Hong , Dong Ying , Quan Jingjing , Smith Robert , Lam Alfred , Weinstein Stephen , Clements Judith , Johnson Newell W. , Gao Jin
Published: July 2010

Background

Very few articles have been written about the expression of kallikreins (KLK4 and KLK7) in oral cancers. Therefore, the purpose of this study was to examine and report on their prognostic potential.

Methods

Eighty archival blocks of primary oral cancers were sectioned and stained for KLK4 and KLK7 by immunohistochemistry. The percentage and the intensity of malignant keratinocyte staining were correlated with patient survival using Cox regression analysis.

Results

Both kallikreins were expressed strongly in the majority of tumor cells in 68 of 80 cases: these were mostly moderately or poorly differentiated neoplasms. Staining was particularly intense at the infiltrating front. Patients with intense staining had significantly shorter overall survival (p < .05).

Conclusion

This is the first observation on the patient survival influenced by kallikrein expression in oral carcinoma. The findings are consistent with those for carcinomas at other sites, in particular the prostate and ovary. KLK4 and/or KLK7 immunohistochemistry seems to have diagnostic and prognostic potential in this disease. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Supramolecular Bioconjugates for Protein and Small Drug Delivery
Authors: Salmaso Stefano , Bersani Sara , Scomparin Anna , Mastrotto Francesca , Caliceti Paolo
Published: July 2010

Supramolecular conjugation techniques have been developed to produce novel nanosized systems by assembling materials with diverse physicochemical and biological features. These techniques have been adapted to obtain innovative bioconjugates to deliver drugs with poor biopharmaceutical properties and nano‐devices with potential “theranostic” activity. Supramolecular drug delivery systems include polymer therapeutics such as drug–polymer bioconjugates, and colloidal carriers such as micelles, liposomes, polyplexes, and organic and inorganic nanoparticles. By virtue of their wide array of chemical composition and properties, polymers represent key elements for the construction of novel supramoelcular formulations.

Polymer bioconjugation is a fledged technique for fabrication of protein–polymer conjugates. PEGylation, in particular, produces derivatives with enhanced pharmacokinetic, immunological, and stability properties as compared to the parent protein. Over the years, new methods have been set up to obtain site‐directed polymer conjugation. In this review we report few grafting to and growing from PEGylation examples for the preparation of therapeutically effective protein bioconjugates.

Supramolecular formulations with unique properties can be also obtained by assembling functional polymers, targeting agents, physicochemical modifiers, and biomodulators. These systems may be designed for disease tissue disposition and cell recognition/penetration. Cyclodextrins, for example, have been functionalized with polyethylene glycol and folic acid to produce tumor‐targeted drug carriers. Interesting results have been obtained with this novel class of drug delivery systems. In addition, responsive polymers have been conjugated to gold nanoparticles to endow a new colloidal platform with triggerable cell disposition properties, which can be exploited either in biomedicine or diagnosis.
Hydroxyapatite/polyurethane scaffold incorporated with drug‐loaded ethyl cellulose microspheres for bone regeneration
Authors: Liu Haohuai , Zhang Li , Shi Pujiang , Zou Qin , Zuo Yi , Li Yubao
Published: July 2010

The purpose of this study is to explore and develop biodegradable scaffold for bone regeneration or tissue engineering with the capacity of controlled drug delivery. Ceftazidime as a model drug was encapsulated in ethyl cellulose (EC) microspheres, which were subsequently incorporated in a hydroxyapatite/polyurethane (HA/PU) composite scaffold to generate an antibiotic drug delivery system. HA/PU scaffolds had an interconnected pore network with an average porosity of about 83%. The presence of microspheres in the composite scaffolds was confirmed by scanning electron microscopy. The drug‐loaded EC microspheres were uniformly distributed in the HA/PU scaffold matrix and showed no significant effect on the pore structure of the scaffold. Incorporation of microspheres into scaffolds significantly reduced the initial burst release, and the system exhibited a sustained release of the model drug for up to 60 days. Moreover, the scaffold with drug‐loaded microspheres was proved to be an effective drug delivery system with good cytocompatibility and antibacterial properties. The novel drug‐loaded microsphere/scaffold composites developed in this study are promising to serve as vehicles for controlled drug delivery in bone regeneration or bone tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Hepatic expression profiling shows involvement of PKC epsilon, DGK eta, Tnfaip, and Rho kinase in type 2 diabetic nephropathy rats
Authors: Gupta Jeena , Gaikwad Anil Bhanudas , Tikoo Kulbhushan
Published: July 2010

Type 2 diabetes is associated with an increased risk for developing fatty liver disease, which results in an increased incidence of diabetic nephropathy. Hence, the present study was conceived to identify transcriptional changes in the liver that can provide molecular mediators for increased risk of developing nephropathy associated with type 2 diabetes. Type 2 diabetes was rendered in male SD rats using both high‐fat diet and low dose of streptozotocin (35 mg/kg, intraperitonially, i.p.). Hepatic gene expression profiling was performed in animals after development of diabetic nephropathy. The gene expression data were validated by RT‐PCR, protein expression, and immunohistochemistry. Gene expression profiling data revealed dramatic increase in expression of PKC epsilon, TNF‐alpha‐induced protein (four‐ to seven‐folds), and decrease in the expression of DGK eta in the liver of diabetic nephropathic rats. Furthermore, there was an increase in expression of genes regulating Rho signaling pathway, which was further confirmed by increase in Rho kinase activity. To the best of our knowledge, this is the first report which shows the involvement of PKC epsilon, DGK eta, Tnfaip, and Rho kinase in the liver of type 2 diabetic rats and its association with diabetic nephropathy. J. Cell. Biochem. 111: 944–954, 2010. © 2010 Wiley‐Liss, Inc.
Phase‐Field Simulation of Long‐Wavelength Line Edge Roughness in Diblock Copolymer Resists
Authors: Bosse August W.
Published: July 2010

We examine stochastic computer simulations of the Leibler‐Ohta‐Kawasaki (LOK) phase‐field model1, 2 and demonstrate that long‐wavelength line edge roughness (LER) and line width roughness (LWR) in a lamellar diblock copolymer resist depend monotonically on quench depth and noise strength, and that the LER and LWR spectra both exhibit a peak at k0–the characteristic wavenumber of mesophase separation in diblock copolymers. For k ⪅ k0, we find that the LER spectrum approximately scales like k−1.6. These observations are consistent with previous theoretical, computational, and experimental examinations LER and LWR in diblock copolymer melts, and thus the LOK phase‐field model should be considered a capable and appropriate framework for future examination of long‐wavelength LER and LWR in block copolymer resist systems.

magnified image
Validation of the Mexican–Spanish version of the EORTC QLQ‐C15‐PAL questionnaire for the evaluation of health‐related quality of life in patients on palliative care
Authors: Suárez‐del‐Real Yolanda , Allende‐Pérez Silvia , Alférez‐Mancera Araceli , Rodríguez Rosa Bertha , Jiménez‐Toxtle Silvia , Mohar Alejandro , Oñate‐Ocaña Luis F.
Published: July 2010

Background: Health‐related quality of life (HRQL) is an important outcome in oncology, particularly in the palliative care setting. The European Organization for Research and Treatment of Cancer (EORTC) QLQ‐C15‐PAL questionnaire is a brief version of QLQ‐C30. Our aim is to validate the Mexican–Spanish version of the QLQ‐C15‐PAL questionnaire to measure HRQL in patients with terminal cancer.

Methods: Consecutive patients with biopsy proven cancer were included in the study. All were treated in a cancer center in Mexico and were referred for palliative care because of far‐advanced, recurrent or metastatic cancer. QLQ‐C15‐PAL questionnaire was applied in the first visit to the Unit and palliative care was offered to all patients depending on their specific necessities.

Results: Eighty‐three patients were enrolled in this study (mean age, 61.2 years). Compliance rates were high; all patients completed to the questionnaire in <20 min and the instrument was well‐received. Five missing values in five different items were found. QLQ‐C15 scales distinguished between other clinically distinct groups of patients. Multi‐trait scaling analysis demonstrated good convergent and discriminant validity. Cronbach's α coefficients were >0.7 in three of four multi‐item scales (0.67 in the fourth). Test–retest scores were consistent in some scales, while improve or worsen in others. Better Global health, Dyspnea, Insomnia, Fatigue and Appetite scales were associated with longer survival.

Conclusion: The Mexican–Spanish version of the EORTC QLQ‐C15‐PAL questionnaire is reliable and valid for HRQL measurement in patients with terminal cancer, and is appropriate for use in clinical trials of Mexican patients. Copyright © 2010 John Wiley & Sons, Ltd.
The interaction of ammonia and xenon with the imidazole glycerol phosphate synthase from Thermotoga maritima as detected by NMR spectroscopy
Authors: Liebold Christoph , List Felix , Kalbitzer Hans Robert , Sterner Reinhard , Brunner Eike
Published: July 2010

The imidazole glycerol phosphate (ImGP) synthase from the hyperthermophilic bacterium Thermotoga maritima is a 1:1 complex of the glutaminase subunit HisH and the cyclase subunit HisF. It has been proposed that ammonia generated by HisH is transported through a channel to the active site of HisF, which generates intermediates of histidine (ImGP) and de novo biosynthesis of 5‐aminoimidazole‐4‐carboxamideribotide. Solution NMR spectroscopy of ammonium chloride‐titrated samples was used to study the interaction of NH3 with amino acids inside this channel. Although numerous residues showed 15N chemical shift changes, most of these changes were caused by nonspecific ionic strength effects. However, several interactions appeared to be specific. Remarkably, the amino acid residue Thr 78—which is located in the central channel—shows a large chemical shift change upon titration with ammonium chloride. This result and the reduced catalytic activity of the Thr78Met mutant indicate a special role of this residue in ammonia channeling. To detect and further characterize internal cavities in HisF, which might for example contribute to ammonia channeling, the interaction of HisF with the noble gas xenon was analyzed by solution NMR spectroscopy using 1H‐15N HSQC experiments. The results indicate that HisF contains three distinct internal cavities, which could be identified by xenon‐induced chemical shift changes of the neighboring amino acid residues. Two of these cavities are located at the active site at opposite ends of the substrate N′‐[(5′‐phosphoribulosyl)formimino]‐5‐aminoimidazole‐4‐carboxamide‐ribonucleotide (PRFAR) binding groove. The third cavity is located in the interior of the central β‐barrel of HisF and overlaps with the putative ammonia transport channel.
1,2,3,6‐tetra‐O‐galloyl‐β‐D‐allopyranose gallotannin isolated, from Euphorbia jolkini, attenuates LPS‐induced nitric oxide production in macrophages
Authors: Park Seung‐Bin , Kim Mi‐Sun , Lee Hee Sang , Lee Seung Ho , Kim Sang‐Hyun
Published: July 2010

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including vasodilatation and macrophage‐mediated immunity. Macrophages express inducible NO synthase (iNOS) and produce NO after lipopolysaccharide (LPS) stimulation. Gallotannins are water‐soluble polyphenols with wide‐ranging biological activities. Various chemical structures of gallotannins occurring in medicinal and food plants that are used worldwide showed several remarkable biological and pharmacological activities. In the present study, we examined the inhibitory effects of gallotannin 1,2,3,6‐tetra‐O‐galloyl‐β‐D‐allopyranose (GT24) isolated from Euphorbia jolkini on the LPS‐induced NO production and underlying mechanisms of action. GT24 dose‐dependently decreased LPS‐induced NO production and iNOS expression in J774A.1 macrophages. In addition, GT24 inhibited LPS‐induced activation of nuclear factor (NF)‐κB as indicated by inhibition of degradation of I‐κBα, nuclear translocation of NF‐κB, and NF‐κB dependent gene reporter assay. Our results suggest that GT24 possesses an inhibitory effect on the LPS‐induced inflammatory reaction. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of E. laciniata (L) Ointment on Mild and Moderate Carpal Tunnel Syndrome: A Double‐blind, Randomized Clinical Trial
Authors: Eftekharsadat Bina , Kazem Shakouri Seyed , Shimia Mohammad , Rahbar Mohammad , Ghojazadeh Morteza , Reza Rashidi Mohammad , Hadi Faraji Mohammad
Published: July 2010

This paper concerns the effects of methanol extract of Eremostachys laciniata on mild and moderate Carpal Tunnel Syndrome (CTS). Forty patients, including sixty hands affected by CTS, were randomly categorized in two different groups. Group A and Group B were treated with E. laciniata extract and placebo as the ointment, respectively. Tests, including the palmar prehension (pound), grip power (kg), visual analog scale (VAS) and electrodiagnostic study, were performed on all patients before and after the trial. During the trial, all patients receive Sodium Diclofenac (25 mg twice a day) orally. In addition, they utilized a night wrist splint. After four weeks of treatment, the state of mean palmer prehension in both groups improved yet, the statistics show that group A prevailed by (p = 0.01). Grip power increased in both groups as well, but this increase was not significant within‐groups (p = 0.18 and p = 0.54 in group A and B, respectively) or between‐groups (p = 0.053). Although the VSA decreased in both groups, group A prevailed again by (p < 0.001). After four weeks, no significant electrodiagnostic change was detected between the two groups. According to this study, the methanol extract of E. laciniata can be effective in treatment of mild and moderate CTS in combination with the wrist night splint, especially in alleviating the severity of the syndrome and increasing the palmer prehension power. Copyright © 2010 John Wiley & Sons, Ltd.
Novel method for producing amorphous rice flours by milling without adding water
Authors: Katsuno Keiji , Nishioka Akihiro , Koda Tomonori , Miyata Ken , Murasawa Go , Nakaura Yoshiko , Inouchi Naoyoshi
Published: July 2010

The present study investigated a novel milling method for producing amorphous rice starch without adding water. A new type of milling machine was developed (termed the shear and heat milling machine (SHMM)), which is capable of applying mechanical shear and heat during the milling process. The SHMM consisted of a pair of rice mortars attached to a servomotor and a ring heater. The heater was installed on the upper mortar; the temperature of the upper mortar was monitored and controlled by a thermal controller. Wide‐angle X‐ray diffraction (WAXD) analysis was used to determine the crystallinities of starch in rice flour samples produced using the SHMM at different milling temperatures. The WAXD data for milled rice flour that had been heated exhibited no diffraction peaks. This experimental result demonstrates that the developed SHMM produces amorphous rice starch easily by milling with heating without the addition of water. The milling conditions such as the shear and heat applied can be used to control the crystallinity of starch in rice.
Repeated cocaine exposure decreases dopamine D2‐like receptor modulation of Ca2+homeostasis in rat nucleus accumbens neurons
Authors: Perez Mariela F. , Ford Kerstin A. , Goussakov Ivan , Stutzmann Grace E. , Hu Xiu‐Ti
Published: July 2010

The nucleus accumbens (NAc) is a limbic structure in the forebrain that plays a critical role in cognitive function and addiction. Dopamine modulates activity of medium spiny neurons (MSNs) in the NAc. Both dopamine D1‐like and D2‐like receptors (including D1R or D1,5R and D2R or D2,3,4R, respectively) are thought to play critical roles in cocaine addiction. Our previous studies demonstrated that repeated cocaine exposure (which alters dopamine transmission) decreases excitability of NAc MSNs in cocaine‐sensitized, withdrawn rats. This decrease is characterized by a reduction in voltage‐sensitive Na+currents and high voltage‐activated Ca2+currents, along with increased voltage‐gated K+currents. These changes are associated with enhanced activity in the D1R/cAMP/PKA/protein phosphatase 1 pathway and diminished calcineurin function. Although D1R‐mediated signaling is enhanced by repeated cocaine exposure, little is known whether and how the D2R is implicated in the cocaine‐induced NAc dysfunction. Here, we performed a combined electrophysiological, biochemical, and neuroimaging study that reveals the cocaine‐induced dysregulation of Ca2+homeostasis with involvement of D2R. Our novel findings reveal that D2R stimulation reduced Ca2+influx preferentially via the L‐type Ca2+channels and evoked intracellular Ca2+release, likely via inhibiting the cAMP/PKA cascade, in the NAc MSNs of drug‐free rats. However, repeated cocaine exposure abolished the D2R effects on modulating Ca2+homeostasis with enhanced PKA activity and led to a decrease in whole‐cell Ca2+influx. These adaptations, which persisted for 21 days during cocaine abstinence, may contribute to the mechanism of cocaine withdrawal. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Multiparametric assessment of acute and subacute ischemic neuronal damage: A small animal positron emission tomography study with rat photochemically induced thrombosis model
Authors: Fukumoto Dai , Hosoya Teruyo , Nishiyama Shingo , Harada Norihiro , Iwata Hiroshi , Yamamoto Shigeyuki , Tsukada Hideo
Published: July 2010

We evaluated sequential changes in rat brain function up to 14 days after focal ischemic insult with a small animal positron emission tomography (PET). Unilateral focal ischemic cerebral damage was induced by left middle cerebral artery occlusion with a photochemically induced thrombosis (PIT) method. PET scans were conducted with [11C](R)‐PK11195 ([11C](R)‐PK) for peripheral benzodiazepine receptor (PBR), [11C]flumazenil ([11C]FMZ) for central benzodiazepine receptor (CBR), and [18F]fluoro‐2‐deoxy‐D‐glucose ([18F]FDG) for glucose metabolism at before (as “Normal”) and after PIT. At 1 and 3 days after PIT, [18F]FDG indicated lower uptake in the infarct area. Interestingly, unexpectedly high‐[18F]FDG uptake was observed in the peri‐infarct area surrounding the infarct area at day 7. The high‐[18F]FDG uptake region completely overlapped with the high‐[11C](R)‐PK uptake region at day 7, which resulted in the underestimation of neuronal damage. Immunohistochemical data also suggested that the high‐[18F]FDG uptake peak at day 7 was caused by inflammation including microglial cell activation. In contrast, imaging with [11C]FMZ indicated cortical neuronal damage on days 7 and 14 without any disturbance by microglial formation. These results indicated that [18F]FDG might not be a suitable ligand for ischemic neuronal damage detection from acute to subacute phases. Synapse, 2010. © 2010 Wiley‐Liss, Inc.
Dendritic morphology of neurons in medial prefrontal cortex, hippocampus, and nucleus accumbens in adult SH rats
Authors: Sánchez Fremioth , Gómez‐Villalobos María de Jesús , Juarez Ismael , Quevedo Lucía , Flores Gonzalo
Published: July 2010

We have studied, in spontaneously hypertensive (SH) rats at different ages (2, 4, and 8 months old), the dendritic morphological changes of the pyramidal neurons of the medial prefrontal cortex (mPFC) and hippocampus and medium spiny neurons of the nucleus accumbens (NAcc) induced by the chronic effect of high‐blood pressure. As control animals, we used Wistar‐Kioto (WK) rats. Blood pressure was measured every 2 months to confirm the increase in arterial blood pressure. Spontaneous locomotor activity was assessed, and then brains were removed to study the dendritic morphology by the Golgi‐Cox stain method followed by Sholl analysis. SH animals at 4 and 8 months of age showed decreased spine density in pyramidal neurons from the mPFC and in medium spiny cells from the NAcc. At 8 months of age as well the pyramidal neurons from the hippocampus exhibited a reduction in the number of dendritic spines. An increase in locomotion in a novel environment at all ages in the SH rats was observed. Our results indicate that high‐blood pressure alters the neuronal dendrite morphology of the mPFC, hippocampus, and NAcc. The increased locomotion behavior supports the idea that dopaminergic transmission is altered in the SH rats. This could enhance our understanding of the consequences of chronic high‐blood pressure on brain structure, which may implicate cognitive impairment in hypertensive patients. Synapse, 2010. © 2010 Wiley‐Liss, Inc.
Nuclear quality control of RNA polymerase II transcripts
Authors: Schmid Manfred , Jensen Torben Heick
Published: July 2010

Eukaryotic RNA polymerase II produces an astounding diversity of transcripts. These may need to be 5′ capped, spliced, polyadenylated, and packaged with proteins before their export to the cytoplasm. Unscheduled accumulation of any RNA species can interfere with normal RNA metabolism and poses a serious hazard to cells. Yet, given the amount of primary transcripts and the complexity of the RNA maturation process, production of aberrant RNA species is unavoidable. Cells, therefore, employ nuclear RNA quality control mechanisms to rapidly degrade, actively retain, or transcriptionally silence unwanted RNAs. Pathways that monitor mRNA production are best understood and similar pathways are employed to destroy transcriptional noise. Finally, related mechanisms also contribute to gene regulation during normal growth. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms
Becoming National: Classroom Language Socialization and Political Identities in the Age of Globalization
Authors: Friedman Debra A.
Published: July 2010

Although schools have long been recognized as primary sites for creating citizens of the modern nation-state, in recent years traditional assimilationist and exclusionist notions of national identity have been challenged by competing values of multiculturalism, hybridity, and transnationalism. This article surveys recent language socialization research that has examined classrooms as sites for socializing novices into political identities associated with membership in a national or transnational community. It explores five broad themes: (a) socialization into the national language, (b) socialization of immigrants, (c) socialization into new forms of national identity, (d) socialization of minority political identities within nation-states, and (e) socialization and transnational identities. The survey concludes with a review of the contributions of a language socialization approach to the study of these issues as well as suggested directions for future research.
Language Socialization in the Workplace
Authors: Roberts Celia
Published: July 2010

This survey article looks first at the changing demands of the workplace in a globalized economy. The new work order creates a new word order, and the workforce has become a “wordforce” (Heller, in press) with new genres of language and communication. These changes have taken place at a time when global flows of people, from less wealthy and secure societies to more wealthy and secure ones, have created multilingual workplaces. Both sets of changes challenge the traditional notion of second language socialization, and this is the focus of the next section. The workplace represents a complex, dynamic setting where migrants experience a double socialization: into the hybrid discourses of the workplace, which all newcomers experience, and into the specific language and cultural practices that realize these discourses. The new language requirements of the workplace produce for migrant workers and professionals a “linguistic penalty” (Roberts & Campbell, 2006) since the communicative demands of the selection process may be greater than those of the job itself. The last section of the article is concerned with language socialization in multilingual settings where language socialization into the dominant language is only part of the story. There is a contrast between the low status multilingualism of migrant workers, and staff in globalized and international organizations who are being socialized into new lingua franca interaction. The article concludes with an example of how the complex linguistic and technical environment of a high-tech multilingual company produces radically different conditions for language socialization which challenge how this notion can be used in the 21st century.
Homelessness among older people and service responses
Authors: Crane Maureen , Warnes Anthony M
Published: July 2010

This paper reviews the limited evidence on the causes of homelessness in old age and on the circumstances and problems of older homeless people, and it describes the few services dedicated to the group. Health care and social care professionals rarely encounter homelessness among the many problems of older people that present to them, but in many developed countries there is evidence that the number of older homeless people has recently been growing. Some among them have been homeless intermittently or continuously for years, but many became homeless for the first time in later life. The reasons for becoming homeless and the problems and needs of the group are exceptionally diverse. Many have been estranged from their family or have no living relatives, and they have a high prevalence of health problems and functional limitations. Although services for homeless people in general have improved since the early 1990s, few have targeted the needs of older people.
Birefringence parameter available for quantitative analysis of human zona hardness
Authors: Iwayama Hiroshi , Hochi Shinichi , Yamashita Masanori
Published: July 2010

This study was designed to investigate whether a non-invasive birefringence parameter, determined using the Oosight™ imaging system, is useful for estimating the hardness of human zona pellucida (ZP). The value for retardance (R) × thickness (T), but not R or T alone, of ZP was positively correlated (r = 0.92, p < 0.0001) with its hardness estimated by the time required for a 0.1% protease solution to solubilize ZP at 37 °C. In a model experiment to induce ZP puncture by Fluorinert™ fluid microinjection (sham-hatching), the R × T value at the punctured site was positively correlated (r = 0.78, p < 0.01) with the hardness of the ZP as estimated by the maximum expansion rate. The R × T values of ZP in in vitro fertilization-derived embryos (21.6 ± 7.5) and intracytoplasmic sperm injection-derived embryos (20.8 ± 6.3) were significantly higher than that in unfertilized metaphase II oocytes (16.6 ± 6.1; p < 0.05). The R × T value after in vitro hatching of viable blastocysts (10.8 ± 6.2) was significantly lower than that of unexpanded morulae and early blastocysts (19.0 ± 4.0; p < 0.05), while the value of expanding blastocysts (15.3 ± 4.1) was intermediate. In conclusion, hardness of human ZP can be estimated non-invasively by birefringence-based microscopic observation.
Stability of the MgSiO3 analog NaMgF3 and its implication for mantle structure in super‐Earths
Authors: Grocholski B. , Shim S.‐H. , Prakapenka V. B.
Published: July 2010

First‐principles calculations on MgSiO3 suggested a breakdown into MgO + SiO2 at pressure above 1000 GPa with an extremely large negative Clapeyron slope, isolating the lowermost mantles of larger super‐Earths (∼10M⊕) from convection. Similar calculations predicted the same type of breakdown in NaMgF3 to NaF + MgF2 at 40 GPa, allowing for experimental examination. We found that NaMgF3 is stable to at least 70 GPa and 2500 K. In our measurements on MgF2 (an SiO2 analog), we found a previously unidentified phase (“phase X”) between the stability fields of pyrite‐type and cotunnite‐type (49–53 GPa and 1500–2500 K). A very small density increase (1%) at the pyrite‐type → phase X transition would extend the stability of NaMgF3 relative to the breakdown products. Furthermore, because phase X appears to have a cation coordination number intermediate between pyrite‐type (6) and cotunnite‐type (9), entropy change (ΔS) would be smaller at the breakdown boundary, making the Clapeyron slope (dP/dT = ΔS/ΔV) much smaller than the prediction. If similar trend occurs in MgSiO3 and SiO2, the breakdown of MgSiO3 may occur at higher pressure and have much smaller negative Clapeyron slope than the prediction, allowing for large‐scale convection in the mantles of super‐Earth exoplanets.
Insight into protein–protein interactions from analytical ultracentrifugation
Authors: Harding Stephen E. , Rowe Arthur J.
Published: July 2010

Analytical ultracentrifugation is a free solution technique with no supplementary immobilization, columns or membranes required, and can be used to study self-association and hetero-interactions, stoichiometry, reversibility and interaction strength across a very large dynamic range (dissociation constants from 10−12 M to 10−1 M). In the present paper, we review some of the advances that have been made in the two different types of sedimentation experiment – sedimentation equilibrium and sedimentation velocity – for the analysis of protein–protein interactions and indicate how major complications such as thermodynamic and hydrodynamic non-ideality can be dealt with.
Evaluating the utility of cardiomyocytes from human pluripotent stem cells for drug screening
Authors: Dick Emily , Rajamohan Divya , Ronksley Jonathon , Denning Chris
Published: July 2010

Functional cardiomyocytes can now be derived routinely from hPSCs (human pluripotent stem cells), which collectively include embryonic and induced pluripotent stem cells. This technology presents new opportunities to develop pharmacologically relevant in vitro screens to detect cardiotoxicity, with a view to improving patient safety while reducing the economic burden to industry arising from high drug attrition rates. In the present article, we consider the need for human cardiomyocytes in drug-screening campaigns and review the strategies used to differentiate hPSCs towards the cardiac lineage. During early stages of differentiation, hPSC-cardiomyocytes display gene expression profiles, ultra-structures, ion channel functionality and pharmacological responses reminiscent of an embryonic phenotype, but maturation during extended time in culture has been demonstrated convincingly. Notably, hPSC-cardiomyocytes have been shown to respond in a highly predictable manner to over 40 compounds that have a known pharmacological effect on the human heart. This suggests that further development and validation of the hPSC-cardiomyocyte model as a tool for assessing cardiotoxicity is warranted.
Identification and characterization of small-molecule ligands that maintain pluripotency of human embryonic stem cells
Authors: Burton Peter , Adams David R. , Abraham Achamma , Allcock Robert W. , Jiang Zhong , McCahill Angela , Gilmour Jane , McAbney John , Kane Nicole M. , Baillie George S. , McKenzie Fergus R. , Baker Andrew H. , Houslay Miles D. , Mountford Joanne C. , Milligan Graeme
Published: July 2010

hESCs (human embryonic stem cells) offer great potential for pharmaceutical research and development and, potentially, for therapeutic use. However, improvements in cell culture are urgently required to allow the scalable production of large numbers of cells that maintain pluripotency. Supplementing feeder-free conditions with either EHNA [erythro-9-(2-hydroxy-3-nonyl)adenine] or readily synthesized analogues of this compound maintains hESC pluripotency in the absence of exogenous cytokines. When the hESC lines SA121 or SA461 were maintained in feeder-free conditions with EHNA they displayed no reduction in stem-cell-associated markers such as Nanog, Oct4 (octamer-binding protein 4) and SSEA4 (stage-specific embryonic antigen 4) when compared with cells maintained in full feeder-free conditions that included exogenously added bFGF (basic fibroblast growth factor). Spontaneous differentiation was reversibly suppressed by the addition of EHNA, but EHNA did not limit efficient spontaneous or directed differentiation following its removal. We conclude that EHNA or related compounds offers a viable alternative to exogenous cytokine addition in maintaining hESC cultures in a pluripotent state and might be a particularly useful replacement for bFGF for large-scale or GMP (good manufacturing practice)-compliant processes.
Biogenesis of the signal recognition particle
Authors: Leung Eileen , Brown Jeremy D.
Published: July 2010

Assembly of ribonucleoprotein complexes is a facilitated quality-controlled process that typically includes modification to the RNA component from precursor to mature form. The SRP (signal recognition particle) is a cytosolic ribonucleoprotein that catalyses protein targeting to the endoplasmic reticulum. Assembly of SRP is largely nucleolar, and most of its protein components are required to generate a stable complex. A pre-SRP is exported from the nucleus to the cytoplasm where the final protein, Srp54p, is incorporated. Although this outline of the SRP assembly pathway has been determined, factors that facilitate this and/or function in quality control of the RNA are poorly understood. In the present paper, the SRP assembly pathway is summarized, and evidence for the involvement of both the Rex1p and nuclear exosome nucleases and the TRAMP (Trf4–Air2–Mtr4p polyadenylation) adenylase in quality control of SRP RNA is discussed. The RNA component of SRP is transcribed by RNA polymerase III, and both La, which binds all newly transcribed RNAs generated by this enzyme, and the nuclear Lsm complex are implicated in SRP RNA metabolism.
The evolution of spliced leader trans-splicing in nematodes
Authors: Pettitt Jonathan , Harrison Neale , Stansfield Ian , Connolly Bernadette , Müller Berndt
Published: July 2010

Spliced leader trans-splicing occurs in many primitive eukaryotes including nematodes. Most of our knowledge of trans-splicing in nematodes stems from the model organism Caenorhabditis elegans and relatives, and from work with Ascaris. Our investigation of spliced leader trans-splicing in distantly related Dorylaimia nematodes indicates that spliced-leader trans-splicing arose before the nematode phylum and suggests that the spliced leader RNA gene complements in extant nematodes have evolved from a common ancestor with a diverse set of spliced leader RNA genes.
Functions of microRNAs in Drosophila development
Authors: Jones Christopher I. , Newbury Sarah F.
Published: July 2010

Control of mRNA translation and degradation has been shown to be key in the development of complex organisms. The core mRNA degradation machinery is highly conserved in eukaryotes and relies on processive degradation enzymes gaining access to the mRNA. Control of mRNA stability in eukaryotes is also intimately linked to the regulation of translation. A key question in the control of mRNA turnover concerns the mechanisms whereby particular mRNAs are specifically degraded in response to cellular factors. Recently, microRNAs have been shown to bind specifically to mRNAs and regulate their expression via repression of translation and/or degradation. To understand the molecular mechanisms during microRNA repression of mRNAs, it is necessary to identify their biologically relevant targets. However, computational methods have so far proved unreliable, therefore verification of biologically important targets at present requires experimental analysis. The present review aims to outline the mechanisms of mRNA degradation and then focus on the role of microRNAs as factors affecting particular Drosophila developmental processes via their post-transcriptional effects on mRNA degradation and translation. Examples of experimentally verified targets of microRNAs in Drosophila are summarized.
What are natural antisense transcripts good for?
Authors: Werner Andreas , Swan Daniel
Published: July 2010

NATs (natural antisense transcripts) are important regulators of eukaryotic gene expression. Interference between the expression of protein-coding sense transcripts and the corresponding NAT is well documented. In the present review, we focus on an additional, higher-order role of NATs that is currently emerging. The recent discovery of endogenous siRNAs (short interfering RNAs), as well as NAT-induced transcriptional gene silencing, are key to the proposed novel function of NATs.