bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Nanoparticles: A Versatile Method for the Reductive, One‐Pot Synthesis of Bare, Hydrophilic and Hydrophobic Magnetite Nanoparticles (Adv. Funct. Mater. 8/2011)
Authors: Yathindranath Vinith , Rebbouh Leila , Moore David F. , Miller Donald W. , van Lierop Johan , Hegmann Torsten 
Published: April 2011

AbstractA biocompatible, reliable, and particularly versatile synthesis of magnetic iron oxide nanoparticles (IONPs) is presented that uses iron(III) acetylacetonate Fe(acac)3 as an iron precursor and sodium borohydride as a reducing agent. Both the reaction temperature and the concentration of the reducing agent have considerable effects on the IONP size. These dependencies can be used to prepare IONPs ranging in size from 5 to 8 nm, as determined by transmission electron microscopy (TEM). Synthesis at room temperature or with higher sodium borohydride concentrations always resulted in smaller particle sizes. Powder X‐ray diffraction patterns show the presence of an iron oxide phase with a cubic unit cell and allow for the determination of the lattice parameters and average crystallite sizes for all synthesized IONPs. Transmission Mössbauer spectroscopy shows that the as‐synthesized IONPs are pure magnetite (Fe3O4) and is further used to elucidate the reaction pathway by analyzing iron intermediates formed prior to nanoparticle formation and precipitation. TEM and high‐resolution TEM reveal quasi‐spherical shapes and lattice fringes for most IONPs. With only minor modifications of the synthesis procedure, this versatile, one‐pot synthesis is proven to be suitable for the production of bare (uncoated) IONPs, IONPs with hydrophilic poly(ethylene glycol), L‐arginine, and L‐glutamic acid coatings, as well as IONPs with hydrophobic coatings such as oleic acid. All coated IONPs were characterized by FT‐IR spectroscopy. In addition, the bare IONPs could easily be modified post‐synthesis with a suitable capping agent using ultrasonication. To verify the biocompatibility of the IONPs, in vitro cytotoxicity studies were carried out on bare IONPs with intestinal (Caco2) and liver epithelial (HepG2) cell cultures using an 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay. Phase contrast microscopy after hematoxylin‐eosin staining showed the intact morphology of the Caco2 and HepG2 cells treated with IONPs.
Surface‐Plasmon Assisted Energy Conversion in Dye‐Sensitized Solar Cells
Authors: Ding Bo , Lee Bong Jae , Yang Mengjin , Jung Hyun Suk , Lee Jung‐Kun 
Published: April 2011

AbstractIn this study, the effect of plasmonic core‐shell structures, consisting of dielectric cores and metallic nanoshells, on energy conversion in dye‐sensitized solar cells (DSSCs) is investigated. The structure of the core‐shell particles is controlled to couple with visible light so that the visible component of the solar spectrum is amplified near the core‐shell particles. In core‐shell particle – TiO2 nanoparticle films, the local field intensity and light pathways are increased due to the surface plasmons and light scattering. This, in turn, enlarges the optical cross‐section of dye sensitizers coated onto the mixed films. When 22 vol% of core‐shell particles are added to a 5 μm thick TiO2 film, the energy conversion efficiency of DSSCs increases from 2.7% to 4.0%, in spite of a more than 20% decrease in the amount of dyes adsorbed on the composite films. The correlation between core‐shell particle content and energy conversion efficiency in DSSCs is explained by the balance among near‐field effects, light scattering efficiency, and surface area in the composite films.
Polyhydrated ionogen enhances postoperative sinonasal ciliated remucosalization
Authors: DePoortere David , Kofonow Jennifer M. , Chiu Alexander G. , Cohen Noam A. 
Published: April 2011

AbstractBackgroundMucosalization of the sinonasal cavity following surgery is critical for successful outcomes. Recently a novel anti‐protease compound, polyhydrated‐ionogen (PHI) with Mg2+/Br−, demonstrated improved dermal wound healing. We set out to investigate the effect of PHI Mg2+/Br− on sinus remucosalization following surgery.MethodsA total of 24 rabbits underwent bilateral medial‐wall maxillary mucosal stripping followed by placement of an indwelling irrigation catheter. In a randomized fashion 1 side received 3 cc normal saline (NS) daily, while the contralateral side received PHI Mg2+/Br−. Following a 14‐day therapeutic trial, remucosalization was assessed by hematoxylin and eosin (H&E) staining and immunohistochemistry for β‐tubulin, a marker of cilia. A semiquantitative grading of ciliated remucosalization was applied with a chi‐square test used to compare distributions for each treatment.ResultsH&E staining comparison demonstrated NS treated sinuses (n = 24) had substantial bare areas with predominant ciliation scores under 30%. The PHI Mg2+/Br−‐treated group (n = 24) achieved a statistically significant improvement in reciliation (>60%) when compared with NS (p < 0.01). These results were confirmed with Type IV β‐tubulin staining (p < 0.01).ConclusionPoor postsurgical sinonasal mucosa healing results in adverse clinical outcomes. In a rabbit model of sinonasal mucosal healing, daily irrigation for 14 days with PHI Mg2+/Br−‐enhanced ciliated remucosalization compared to saline. © 2011 ARS‐AAOA, LLC.
Oral corticosteroid therapy in chronic rhinosinusitis without polyposis: a systematic review
Authors: Lal Devyani , Hwang Peter H. 
Published: April 2011

AbstractBackgroundRecognition of inflammation in the pathophysiology of chronic rhinosinusitis (CRS) has caused corticosteroid therapy in CRS to gain favor. A systematic evaluation of oral steroid use in CRS without nasal polyps (CRSsNP) has not been previously conducted. The objective of the study was to assess evidence on oral steroid therapy in CRSsNP, via a systematic literature review.MethodsOvid and PubMed databases were searched for studies on oral steroid therapy in CRSsNP. Manuscripts were reviewed and graded by evidence‐based medicine (EBM) level.ResultsA total of 33 studies met inclusion criteria; 30 on CRSsNP and 3 on allergic fungal sinusitis (AFS). CRSsNP studies did not include any randomized controlled trial (RCT) or any clinical study employing systemic corticosteroids alone. They included 20 reviews/expert opinions (Level 5) with differing recommendations, and 4 treatment guidelines (Level 4) with weak recommendations on use. Three studies, 2 retrospective (Level 4) and 1 prospective study (Level 3), used oral steroids in combination with antibiotics and nasal steroids. The multidrug regimen improved symptoms, radiologic findings, short‐term relapses, nasal endoscopy, and cytokine pattern expression. An experimental study (Level 5) found oral steroids to reverse sinonasal tissue inflammation. Two studies in animal models (Level 5) found no benefit of adding systemic steroids to antibiotics. Three clinical AFS studies, 1 RCT (Level 1) and 2 prospective (Level 3), found oral steroids to benefit postoperative recurrence, endoscopy or computed tomography (CT).ConclusionNo study has employed systemic corticosteroids alone in treating CRSsNP. Evidence supporting oral steroid therapy in CRSsNP is mostly Level 4 or 5; there is lack of any RCT to support use. © 2011 ARS‐AAOA, LLC.
Periostin and osteopontin are overexpressed in chronically inflamed sinuses
Authors: Daines Steven Marc , Wang Yong , Orlandi Richard R. 
Published: April 2011

AbstractObjectiveIn chronic rhinosinusitis (CRS), the inflammation leads to a proliferative response in the extracellular matrix (ECM). Periostin and osteopontin are 2 ECM proteins which have received attention for their roles in tissue remodeling in inflammatory diseases of the upper and lower airways. Transforming growth factor beta‐1 (TGFβ1) is an inflammatory cytokine that has been implicated in fibrotic conditions affecting virtually every organ. In this study we seek to evaluate the differential expression of periostin, osteopontin, and TGFβ1 in the ethmoid sinus and nasal floor of patients with CRS. Furthermore, we seek to determine if a correlation exists between their differential expression in the nose and sinuses of patients with CRS.MethodsBiopsies from ethmoid sinus and nasal floor mucosa were taken from 15 patients undergoing functional endoscopic sinus surgery (FESS) for CRS. Complementary DNA (cDNA) microarray analysis demonstrated upregulation of periostin and osteopontin in the ethmoid sinus samples. Quantitative real‐time polymerase chain reaction (RT‐PCR) was performed for periostin, osteopontin, and TGFβ1. Statistical analysis was undertaken to examine correlations between the 3 genes of interest.ResultsRT‐PCR confirmed that periostin and osteopontin were overexpressed in the ethmoid samples compared to the nasal floor. The differential expression of both periostin and osteopontin showed significant correlation with TGFβ1.ConclusionPeriostin and osteopontin appear to be involved in ECM remodeling seen in CRS. TGFβ1 may be an upstream inducer of CRS‐related changes in ethmoid sinus mucosa. © 2011 ARS‐AAOA, LLC.
The efficacy of hemostatic techniques in the sheep model of carotid artery injury
Authors: Valentine Rowan , Boase Sam , Jervis‐Bardy Josh , Dones Cabral Jay‐Dee , Robinson Simon , Wormald Peter‐John 
Published: April 2011

AbstractBackgroundThe most dramatic complication in endonasal surgery is inadvertent injury to the internal carotid artery (ICA) with massive bleeding. Nasal packing is the favored technique for control; however, this often causes complete carotid occlusion or carotid stenosis, contributing to the morbidity and mortality of the patient. The aim of this study is to compare the efficacy of endoscopically applied hemostatic techniques that maintain vascular flow in an animal model of carotid artery injury.MethodsA total of 20 sheep underwent ICA dissection/isolation followed by the placement of the artery within a modified “sinus model otorhino neuro trainer” (SIMONT) model. A standardized 4‐mm carotid artery injury was created endoscopically. Randomization of sheep to receive 1 of 5 hemostatic techniques was performed (Floseal, oxidized regenerated cellulose, Chitosan gel, muscle patch, or the U‐Clip anastomotic device). Specific outcome measures were time to hemostasis, duration of time mean arterial pressure (MAP) was >55 mmHg, blood loss, and survival time.ResultsMuscle patch hemostasis and the U‐Clip anastomotic device were significantly more effective at achieving primary hemostasis rapidly, reducing total blood loss, and increasing survival time and time MAP was >55 mmHg more than Floseal, oxidized regenerated cellulose, and Chitosan gel (p < 0.05). Additionally, all muscle patch–treated and U‐Clip device–treated sheep achieved primary hemostasis and reached the endpoint of observation, while maintaining vascular patency. Floseal and oxidized regenerated cellulose failed to achieve hemostasis in any animal, with all animals exsanguinating prematurely.ConclusionIn the sheep model of endoscopic ICA injury, the muscle patch and U‐Clip anastomotic device significantly improved survival, reduced blood loss, and achieved primary hemostasis while maintaining vascular patency. © 2011 ARS‐AAOA, LLC.
Die Chemie und der Wurm: Caenorhabditis elegans als Plattform für das Zusammenführen von chemischer und biologischer Forschung
Authors: Hulme S. Elizabeth , Whitesides George M. 
Published: April 2011

AbstractDieser Aufsatz diskutiert die Nützlichkeit des Wurms Caenorhabditis elegans als Modellorganismus für Chemiker, die an der Untersuchung lebender Systeme interessiert sind. C. elegans, ein 1 mm langer Rundwurm, ist ein beliebter Modellorganismus in nahezu allen Gebieten der modernen Biologie. Der Wurm hat zahlreiche Eigenschaften, die ihn für die Biologie attraktiv machen: Er ist klein (<1000 Zellen), transparent und genetisch leicht zu manipulieren. Trotz seiner Schlichtheit weist der Wurm komplexe Phänotypen auf, die mit seiner Mehrzelligkeit zusammenhängen: Er hat differenzierte Zelltypen und Organe, er altert und hat eine wohldefinierte Lebenserwartung, er kann lernen und besitzt ein Erinnerungsvermögen. Der Aufsatz will verdeutlichen, dass diese Mischung aus Einfachheit und Komplexität den Wurm zu einem besonders nützlichen Werkzeug macht, um die Beziehungen zwischen Phänomenen auf molekularer Ebene und der Ebene des Gesamtorganismus zu erforschen (Altern, Verhalten, Kognition, Anfälligkeit für Krankheiten). Es werden vornehmlich solche Forschungsarbeiten vorgestellt, die chemisch relevant sind. Außerdem werden Instrumente und Arbeitstechniken – biologischer, chemischer und physikalischer Natur – vorgestellt, die uns zur Erforschung des Wurms zur Verfügung stehen.
A simple non‐minimum phase zero's predictor for open‐loop unstable processes
Authors: Nasution Anggi Arifin , Jeng Jyh‐Cheng , Huang Hsiao‐Ping 
Published: April 2011

AbstractThis paper proposes a Smith‐type predictive compensator for open‐loop unstable processes that have non‐minimum phase zero. It has been well‐recognized that this type of predictor reported in the literature encounters internally unstable problem when applied to an open‐loop unstable process. To satisfy the internal stability, the proposed predictor utilizes the partial internal model principle. And, the controller is designed by internal mode control principal to have H2 optimal performance. Simulation examples are presented to illustrate that the proposed control scheme can give satisfactory performance and robustness. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
An Adamantane‐Based Building Block for DNA Networks
Authors: Pathak Richa , Marx Andreas 
Published: April 2011

AbstractDNA governs the storage and transfer of genetic information through generations in all living systems with the exception of some viruses. Its physicochemical nature and the Watson–Crick base pairing properties allow molecular constructions at nanometer length, thereby enabling the design of desired structural motifs, which can self‐assemble to form large supramolecular arrays and scaffolds. The tailor‐made DNAs have been an interesting material for such designed nanoscale constructions. However, the synthesis of specific structures with a desired molecular function is still in its infancy and therefore has to be further explored. To add a new dimension to this approach, we have synthesized a rigid three‐way branched adamantane motif, which is capable of forming highly stable DNA networks. The moiety generated could serve as a useful building block for DNA‐based nanoconstructions.
Growing muscle has different sarcolemmal properties from adult muscle: A proposal with scientific and clinical implications
Authors: Grounds Miranda D. , Shavlakadze Thea 
Published: April 2011

AbstractWe hypothesise that the sarcolemma of an actively growing myofibre has different properties to the sarcolemma of a mature adult myofibre. Such fundamentally different properties have clinical consequences for the onset, and potential therapeutic targets, of various skeletal muscle diseases that first manifest either during childhood (e.g. Duchenne muscular dystrophy, DMD) or after cessation of the main growth phase (e.g. dysferlinopathies). These characteristics are also relevant to the selection of both tissue culture and in vivo models employed to study such myopathies and the molecular regulation of adult myofibres. During growth, multinucleated myofibres increase enormously in size and volume with dramatic increases in length (up to ∼600 mm). This is in striking contrast with most mononucleated cells such as fibroblasts, that remain at a relatively small size (∼10–20 µm diameter). The consequences of a dynamic, expanding sarcolemma during growth, compared with that of an adult myofibre of a fixed length, are discussed with respect to various aspects of muscle biology.
Synthesis of β‐Pyrrolic‐Modified Porphyrins and Their Incorporation into DNA
Authors: Stephenson Adam W. I. , Partridge Ashton C. , Filichev Vyacheslav V. 
Published: April 2011

AbstractA synthetic methodology for the synthesis of various β‐pyrrolic‐functionalised porphyrins and their covalent attachment to 2′‐deoxyuridine and DNA is described. Palladium(0)‐catalysed Sonogashira and copper(I)‐catalysed Huisgen 1,3‐dipolar cycloaddition reactions were used to insert porphyrins into the structure of 2′‐deoxyuridine and DNA. Insertion of a porphyrin into the middle of single‐stranded CT oligonucleotides possessing a 5′‐terminal run of four cytosines was shown to trigger the formation of pH‐ and temperature‐dependent i‐motif structures. Porphyrin insertion also led to the aggregation of single‐stranded purine–pyrimidine sequences, which could be dissociated by heating at 90 °C for 5 min. Parallel triplexes and anti‐parallel duplexes were formed in the presence of the appropriate complementary strand(s). Depending on the modification, porphyrins were placed in the major and minor grooves of duplexes and were used as bulged intercalating insertions in duplexes and triplexes. In general, the thermal stabilisation of parallel triplexes possessing porphyrin‐modified triplex‐forming oligonucleotide (TFO) strands was observed, whereas anti‐parallel duplexes were destabilised. These results are compared and discussed on the basis of the results of molecular modelling calculations.
Enantioselective Copper‐Catalysed Propargylic Substitution: Synthetic Scope Study and Application in Formal Total Syntheses of (+)‐Anisomycin and (−)‐Cytoxazone
Authors: Detz Remko J. , Abiri Zohar , le Griel Remi , Hiemstra Henk , van Maarseveen Jan H. 
Published: April 2011

AbstractA copper catalyst with a chiral pyridine‐2,6‐bisoxazoline (pybox) ligand was used to convert a variety of propargylic esters with different side chains (R=Ar, Bn, alkyl) into their amine counterparts in very high yields and with good enantioselectivities (up to 90 % enantiomeric excess (ee)). Different amine nucleophiles were applied in the reactions and the highest enantioselectivities were obtained for aniline and its analogues. Interestingly, some carbon nucleophiles could also be used and with indoles excellent ee values were obtained (up to 98 % ee). The versatility of the propargylic amines obtained was demonstrated by their further elaboration to formal total syntheses of the antibiotic (+)‐anisomycin and the cytokine modulator (−)‐cytoxazone.
Virus‐Sized DNA Nanoparticles for Gene Delivery Based on Micelles of Cationic Calixarenes
Authors: Rodik Roman V. , Klymchenko Andrey S. , Jain Namrata , Miroshnichenko Stanislav I. , Richert Ludovic , Kalchenko Vitaly I. , Mély Yves 
Published: April 2011

AbstractMacrocyclic amphiphilic molecules based on calix[4]arenes are highly attractive for controlled supramolecular assembly of DNA into small nanoparticles, since they present a unique conical architecture and can bear multiple charged groups. In the present work, we synthesized new amphiphilic calixarenes bearing cationic groups at the upper rim and alkyl chains at the lower rim. Their self‐assembly in aqueous solution was characterized by fluorescent probes, fluorescence correlation spectroscopy, dynamic light scattering, gel electrophoresis and atomic force microscopy. We found that calixarenes bearing long alkyl chains (octyl) self‐assemble into micelles of 6 nm diameter at low critical micellar concentration and present the unique ability to condense DNA into small nanoparticles of about 50 nm diameter. In contrast, the short‐chain (propyl) analogues that cannot form micelles at low concentrations failed to condense DNA, giving large polydisperse DNA complexes. Thus, formation of small DNA nanoparticles is hierarchical, requiring assembly of calixarenes into micellar building blocks that further co‐assemble with DNA into small virus‐sized particles. The latter showed much better gene transfection efficiency in cell cultures relative to the large DNA complexes with the short‐chain analogues, which indicates that gene delivery of calixarene/DNA complexes depends strongly on their structure. Moreover, all cationic calixarenes studied showed low cytotoxicity. Thus, this work presents a two‐step hierarchical assembly of small DNA nanoparticles for gene delivery based on amphiphilic cone‐shaped cationic calixarenes.
Antioxidant property and production of exopolysaccharide from Armillaria mellea in submerged cultures: Effect of culture aeration rate
Authors: Lung Ming Y. , Hsieh Chih W. 
Published: April 2011

AbstractEffects of culture aeration rate on production and antioxidant property of exopolysaccharide (EPS) by Armillaria mellea were investigated in a 5‐L stirred‐tank bioreactor where an optimal biomass aeration rate of 1.2 vvm with 0.22 g/g cell yield and 0.6 vvm EPS formation rate with 7.66 mg/g product yield were achieved. A two‐stage aeration process to maximize the biomass and EPS productions proceeded with a 1.55‐fold enhancement (from 4.28 to 6.65 g/L) in biomass formation and a 2.68‐fold enhancement (from 86.9 to 233.2 mg/L) in the EPS production, as compared with those from the aeration rate of 0.3 vvm. The molecular weights of EPS in cultures of different aeration rates are closely correlated with their protein/polysaccharide ratios (R2=0.830) and EC50 (EC50, the effective concentration where the antioxidant property is 50%) values in antioxidant activity (R2=0.960), reducing power (R2=0.894) and chelating ability (R2=0.954). EPS from the two‐stage aeration rate culture shows a strong antioxidant property by the conjugated diene method, reducing power and chelating ability on ions. Therefore, we present results to regulate and to optimize A. mellea cultures to efficiently produce biomass and EPS. The fermented EPS has the potential to be used as for antioxidant‐related functional foods and pharmaceutical industries.
Depression of cortical activity in humans by mild hypercapnia
Authors: Thesen Thomas , Leontiev Oleg , Song Tao , Dehghani Nima , Hagler Donald J , Huang Mingxiong , Buxton Richard , Halgren Eric 
Published: April 2011

AbstractThe effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event‐related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level‐dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH‐modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.