bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation, characterization and luminescence properties of BiPO4:Eu nanophosphors
Authors: Zhou Xiaochun , Wang Xiaojun 
Published: September 2012

ABSTRACTA facile chemical method was employed to prepare fine BiPO4:Eu3+ phosphor particles calcined at the same temperature. Introducing lithium greatly affected the morphology of the samples and further affected the luminescence intensity. The samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. The XRD patterns of BiPO4:Eu3+ indicated a monoclinic phase. From the fluorescence spectra, the emission transition 5D0 → 7F1 is more prominent than the normal red emission transition 5D0 → 7F2. Based on the intensity ratios of 5D0 → 7F2 to 5D0 → 7F1 in the emission spectra, it can be concluded that introducing Li+ can improve the symmetry of the crystal lattice and modify the emission intensity. Sharp lines at 395 nm are the strongest of the f–f transitions and match well with near‐UV LED chips. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of amylose deposition on potato tuber starch granule architecture and dynamics as studied by lintnerization
Authors: Wikman Jeanette , Blennow Andreas , Bertoft Eric 
Published: September 2012

AbstractThe effect of amylose deposition on the amylopectin crystalline lamellar organization in potato starch granules was studied by mild acid, so‐called lintnerization, of potato tuber starch transgenically engineered to deposit different levels of amylose. The starch granules were subjected to lintnerization at different temperatures (25, 35, and 45°C) and to two levels of solubilization, ∼ 45 and 80%. The rate of the lintnerization increased with temperature but was suppressed by amylose. The molecular size of the lintner dextrins increased with temperature, but this effect was suppressed by the presence of amylose. At high temperatures and low‐amylose content, the degree of branches was high with the concomitant increase in size in the dextrins. A portion of the branches was resistant to debranching enzymes possibly due to specific structural formations. The effects of temperature suggested a unique granular architecture of potato starch, and a model showing the dependence of temperature on the dynamic arrangement of amylopectin and amylose in the crystalline and amorphous lamellae for the potato starch is suggested. © 2012 Wiley Periodicals, Inc.
Synthetic adhesive oligopeptides with rigid polyhydroxylated amino acids
Authors: Deshmukh Manjeet , Singh Shashi , Geyer Armin 
Published: September 2012

AbstractSynthetic oligopeptides containing polyhydroxylated bicyclic dipeptide (GlcTap) are investigated for their adhesion properties. The non‐natural amino acid building block composed of GlcTap is derived from glucuronic acid and mimics the hydroxyl‐amino acids of the natural proteins. Peptide oligomers of GlcTap flanked by the amino acids Tyr and Lys were synthesized and characterized. Solution structural studies performed by circular dichromism spectroscopy suggests that poly(LysGlcTapTyr) and poly(GlcTapTyr) adopts extended helical structures. Adhesion of these oligomers to the mica surface is shown by atomic force microscopy spectroscopy. Studies indicate that extended polyproline II polyhydroxylated peptide chains, which bear additional phenolic as well as cationic side chains, can mimic some of the adhesion properties of the natural protein models. Furthermore, obtained data suggest that poly(GlcTapTyr) and poly(LysGlcTapTyr) as outstanding adhesive compounds, which combine efficient synthetic accessibility with promising adhesive properties. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 273–281, 2013.
Review peptides and proteins wired into the electrical circuits: An SPM‐based approach
Authors: Sek Slawomir 
Published: September 2012

AbstractDevelopment of molecular scale electronics stimulates the search for new functional materials and compounds. One of the promising directions of further growth within this field is bioelectronics, which assumes the use of electron transfer (ET)‐mediating properties of bio‐related compounds. Because of the structural and functional versatility, peptides and proteins are particularly well suited to perform as single‐molecule‐based elements of circuits or sensing devices. In this review, it is demonstrated that purposely designed systems such as molecular junctions are excellent platforms for the studies of ET properties of peptides and proteins at nanoscale level. Using experimental approach based on scanning probe microscopy, individual molecules can be directly wired between two metallic contacts, and their conductance can be determined. ET behavior of the peptides and proteins can be analyzed in terms of their applicability as molecular wires, switches, diodes and elements of sensing devices. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 71–81, 2013.
Design, expression, and purification of de novo transmembrane “hairpin” peptides
Authors: Tulumello David V. , Johnson Rachel M. , Isupov Inga , Deber Charles M. 
Published: September 2012

AbstractWhile our understanding of the folding and structure of water‐soluble proteins has progressed to the point where they can be artificially designed and produced from first principles, there has been only limited work toward the de novo design of membrane proteins. Such studies have been hindered in large part due to the practical challenges in the production and characterization of multispanning transmembrane (TM) proteins that arise from their highly hydrophobic character. In this work, we used molecular biology cloning techniques to produce a library of partially randomized Ala‐ and Ile‐rich de novo helix–loop–helix (hairpin) TM constructs as models for tertiary TM–TM folding. From this plasmid DNA library, we selected sequences corresponding to hairpins with 0, 1, or 2 putative TM segments. While purification protocols could be adapted for application with a broad range of designed protein hairpins, bacterial expression of constructs with multiple predicted TM segments was limited as it is with native membrane proteins. Examples of the peptide hairpins obtained were characterized by circular dichroism spectroscopy, tryptophan fluorescence, and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS‐PAGE). We found that hairpins composed of two TM segments display characteristic behavior on detergent solubilization, such as an increase in helical structure (vs. that in aqueous buffer), and sequence‐dependent migration rates in SDS‐PAGE analysis—features that may serve as structural hallmarks to verify dual TM topology in hairpin sequences. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 546–556, 2012.
Quantifying the branching frequency of virtual filamentous microbes using fractal analysis
Authors: Barry David J. 
Published: September 2012

AbstractThe productivity of an industrial fermentation process involving a filamentous microbe is heavily dependent on the morphological form adopted by the organism. The development of systems capable of rapidly and accurately characterizing morphology within a given process represents a significant challenge, as the complex phenotypes that are manifested are not easily quantified. Conventional parameters employed in these analyses are often of limited value, as they reveal little about the branching behavior of the organism; an important consideration given the demonstrated link between branching frequency and metabolite production. In this study, the influence of branching behavior on the spatial distribution of mycelia grown in silico is examined through fractal analysis. It is demonstrated that fractal dimension, quantified based on the frequency distribution of parameterized boundary curves, and lacunarity act as robust estimators of branching behavior. The analysis can, in theory, be applied to any morphological form, providing universally applicable process parameters for more complete data acquisition. Biotechnol. Bioeng. 2013; 110: 437–447. © 2012 Wiley Periodicals, Inc.
Dynamic transcription factor activity profiling in 2D and 3D cell cultures
Authors: Bellis Abigail D. , Bernabé Beatriz Peñalver , Weiss Michael S. , Shin Seungjin , Weng Stanley , Broadbelt Linda J. , Shea Lonnie D. 
Published: September 2012

AbstractLive‐cell assays to measure cellular function performed within 3D cultures have the potential to elucidate the underlying processes behind disease progression and tissue formation. Cells cultured in 3D interact and remodel their microenvironment and can develop into complex structures. We have developed a transcription factor (TF) activity array that uses bioluminescence imaging (BLI) of lentiviral delivered luminescent reporter constructs that allows for the non‐invasive imaging of TF activity in both 2D and 3D culture. Imaging can be applied repeatedly throughout culture to capture dynamic TF activity, though appropriate normalization is necessary. We investigated in‐well normalization using Gaussia or Renilla luciferase, and external well normalization using firefly luciferase. Gaussia and Renilla luciferase were each unable to provide consistent normalization for long‐term measurement of TF activity. However, external well normalization provided low variability and accounted for changes in cellular dynamics. Using external normalization, dynamic TF activities were quantified for five TFs. The array captured expected changes in TF activity to stimuli, however the array also provided dynamic profiles within 2D and 3D that have not been previously characterized. The development of the technology to dynamically track TF activity within cells cultured in both 2D and 3D can provide greater understanding of complex cellular processes. Biotechnol. Bioeng. 2013; 110: 563–572. © 2012 Wiley Periodicals, Inc.
Towards a universal method for protein refolding: The trimeric beta barrel membrane Omp2a as a test case
Authors: Roussel Guillaume , Perpète Eric A. , Matagne André , Tinti Emmanuel , Michaux Catherine 
Published: September 2012

AbstractIt has recently been reported that 2‐methyl‐2,4‐pentanediol (MPD) can modulate the protein‐binding properties of sodium dodecyl sulfate (SDS), turning it into a non‐denaturing detergent. Indeed both alpha (the lysozyme) and beta (the carbonic anhydrase II) soluble enzymes, as well as a beta membrane protein (PagP) have been successfully refolded into their native form by using this amphiphatic alcohol. In order to support the universal character of our MPD‐based technique, we have extended its transferability to the Omp2a trimeric membrane porin. The far‐UV circular dichroism signature of Omp2a refolded with our original procedure is identical to that obtained by classical techniques, clearly indicating a proper refolding. Moreover, we show that the optimal SDS/MPD ratio for refolding Omp2a is similar to what has been observed for other types of proteins. While the protocol allows refolding at higher protein concentration (up to 4 mg/mL) and ionic strength (up to 1 M NaCl) than other refolding methods, it is also more efficient at basic pH values and medium temperature (20–40°C). Finally, the key role of the cosolvent was highlighted by a thorough study of the efficiency of MPD analogues, and a high variability was observed, as they can be able or unable to induce refolding at low or high salt concentrations. Biotechnol. Bioeng. 2013; 110: 417–423. © 2012 Wiley Periodicals, Inc.
Combination of FASP and fully automated 2D‐LC‐MS/MS allows in‐depth proteomic characterization of mouse zymogen granules
Authors: Sun Xionghua , Jiang Xiaogang 
Published: September 2012

ABSTRACTZymogen granule (ZG) constituents play important roles in pancreatic injury and disease. In previous studies, proteomic analyses with rat zymogen granules were separated by two‐dimensional gel electrophoresis or one‐dimensional SDS–PAGE, followed by in‐gel tryptic digestion. In order to overcome the disadvantage of in‐gel digestion and to carry out further in‐depth proteomic analysis of the zymogen granules, in this study, by combining a filter‐aided sample preparation method and fully automated 2D‐LC‐MS/MS technique, 800 ZG proteins were identified with at least two unique peptides for each protein, 75% of which have not been previously reported. The identified proteins revealed broad diversity in protein identity and function. This is the largest dataset of ZG proteome, and also the first dataset of the mouse ZG proteome, which may help elucidate on the molecular architecture of ZGs and their functions. Copyright © 2012 John Wiley & Sons, Ltd.
BDNF Val66Met polymorphism interacts with sex to influence bimanual motor control in healthy humans
Authors: Smolders Ruud , Rijpkema Mark , Franke Barbara , Fernández Guillén 
Published: September 2012

AbstractBrain‐derived neurotrophic factor (BDNF) plays a critical role in brain development. A common single nucleotide polymorphism in the gene encoding BDNF (rs6265, Val66Met) affects BDNF release and has been associated with altered learning and memory performance, and with structural changes in brain morphology and corpus callosum integrity. BDNF Val66Met has more recently been shown to influence motor learning and performance. Some of the BDNF effects seem to be modulated by an individual's sex, but currently the relationship between BDNF and sex in the motor domain remains elusive. Here, we investigate the relationship between BDNF Val66Met genotype and an individual's sex in the motor system. Seventy‐six healthy, previously genotyped, individuals performed a task in which the participant drew lines at different angles of varying difficulty. Subjects controlled the horizontal and vertical movement of the line on a computer screen by rotating two cylinders. We used this bimanual motor control task to measure contributions from both current motor function and the pre‐existing interhemispheric connectivity. We report that BDNF genotype interacts with sex to influence the motor performance of healthy participants in this bimanual motor control task. We further report that the BDNF genotype by sex interaction was present in the more difficult trials only, which is in line with earlier findings that genetic effects may become apparent only when a system is challenged. Our results emphasize the importance of taking sex into account when investigating the role of BDNF genotype in the motor system.
Cellular basis for singing motor pattern generation in the field cricket (Gryllus bimaculatus DeGeer)
Authors: Schöneich Stefan , Hedwig Berthold 
Published: September 2012

AbstractThe singing behavior of male crickets allows analyzing a central pattern generator (CPG) that was shaped by sexual selection for reliable production of species‐specific communication signals. After localizing the essential ganglia for singing in Gryllus bimaculatus, we now studied the calling song CPG at the cellular level. Fictive singing was initiated by pharmacological brain stimulation. The motor pattern underlying syllables and chirps was recorded as alternating spike bursts of wing‐opener and wing‐closer motoneurons in a truncated wing nerve; it precisely reflected the natural calling song. During fictive singing, we intracellularly recorded and stained interneurons in thoracic and abdominal ganglia and tested their impact on the song pattern by intracellular current injections. We identified three interneurons of the metathoracic and first unfused abdominal ganglion that rhythmically de‐ and hyperpolarized in phase with the syllable pattern and spiked strictly before the wing‐opener motoneurons. Depolarizing current injection in two of these opener interneurons caused additional rhythmic singing activity, which reliably reset the ongoing chirp rhythm. The closely intermeshing arborizations of the singing interneurons revealed the dorsal midline neuropiles of the metathoracic and three most anterior abdominal neuromeres as the anatomical location of singing pattern generation. In the same neuropiles, we also recorded several closer interneurons that rhythmically hyper‐ and depolarized in the syllable rhythm and spiked strictly before the wing‐closer motoneurons. Some of them received pronounced inhibition at the beginning of each chirp. Hyperpolarizing current injection in the dendrite revealed postinhibitory rebound depolarization as one functional mechanism of central pattern generation in singing crickets.
Structural Investigations on the Anti‐HIV G‐Quadruplex‐Forming Oligonucleotide TGGGAG and Its Analogues: Evidence for the Presence of an A‐Tetrad
Authors: Virgilio Antonella , Esposito Veronica , Citarella Giuseppe , Mayol Luciano , Galeone Aldo 
Published: September 2012

AbstractSeveral anti‐HIV aptamers adopt DNA quadruplex structures. Among these, “Hotoda's aptamer” (base sequence TGGGAG) was one of the first to be discovered. Although it has been the topic of some recent research, no detailed structural investigations have been reported. Here we report structural investigations on this aptamer and analogues with related sequences, by using UV, CD, and NMR spectroscopy as well as electrophoretic techniques. The addition of a 3′‐end thymine has allowed us to obtain a single, investigable quadruplex structure. Data clearly point to the presence of an A‐tetrad. Furthermore, the effects of the incorporation of an 8‐methyl‐2′‐deoxyguanosine at the 5′‐end of the G‐run were investigated.
Porcine model of intracoronary pulverization of stent struts by rotablation atherectomy
Authors: Quang Thuy Tran , Hatem Raja , Rousseau Guy , Dube Bruno , Samson Caroline , Schampaert Erick , Charron Thierry 
Published: September 2012

ObjectiveTo evaluate the feasibility and safety of rotablation atherectomy in a suboptimally expanded stent.MethodsSeven pigs underwent suboptimal stent expansion in the left anterior descending coronary. Pulverization of the stent struts was performed by rotablation atherectomy with two different burr sizes. Two types of control porcine models were used: pigs with fully expanded stents and pigs without stents. Continuous electrocardiogram readings as well as microscopic and radiologic analysis of cardiac tissue were performed.ResultsRotablation atherectomy reduces the suboptimally expanded stent by (26.95 ± 5.03)%. Ninety‐five percent of the metal microparticles, imbedded in the suboptimally expanded stent group cardiac tissue, are less than 15 μm. Transient vasospasm and ST segments elevations were observed during rotablation atherectomy, which returned to basal conditions at the end of the intervention.ConclusionOur study demonstrated the feasibility and safety of using rotablation atherectomy to pulverize stent struts in a suboptimally expanded stent. © 2012 Wiley Periodicals, Inc.
Investigation of Promoted Cu/ZnO/Al2O3 Methanol Steam Reforming Nanocatalysts by Full Factorial Design
Authors: Sharifi Pajaie H. , Taghizadeh M. 
Published: September 2012

AbstractA Cu/ZnO/Al2O3 nanocatalyst was applied for hydrogen production via steam reforming of methanol in a fixed‐bed reactor. Modified forms of the catalyst were prepared by adding small amounts of Ba, Zr, and Ce oxides. The catalysts were characterized by means of N2 adsorption‐desorption, X‐ray diffraction, and scanning electron microscope techniques. Full factorial design was used to optimize the required number of experiments and evaluate the catalytic activity in a fixed‐bed reactor. The oxide additives reduced the production of carbon monoxide and increased the selectivity of carbon dioxide as well as the yield of hydrogen production. Among the studied catalysts, the Cu/ZnO/Al2O3/CeO2/ZrO2 catalyst presented the best performance.
Independent Association Between Obstructive Sleep Apnea and Noncalcified Coronary Plaque Demonstrated by Noninvasive Coronary Computed Tomography Angiography
Authors: Sharma Sunil , Gebregziabher Mulugeta , Parker Adrian T. , Abro Joseph A. , Armstrong Andrew M. , Schoepf U. Joseph 
Published: September 2012

AbstractBackground:Coronary artery atherosclerosis has been associated with obstructive sleep apnea (OSA). However, the type and severity of plaque formation have not been characterized. This study evaluated the association of coronary noncalcified plaques and severity of stenosis in patients with OSA.Hypothesis:Methods:This study was a retrospective analysis of 81 patients, 49 with OSA and 32 without OSA, who had undergone multidetector‐row helical computed tomography scanning. The board‐certified radiologist was blinded to the diagnosis of OSA and reviewed the scans for plaque characterization, severity of stenosis, and number of vessels involved.Results:Of the 81 patients reviewed, the mean apnea‐hypopnea index in the OSA group was 42.2 vs 7.5 in the non‐OSA group. The groups did not significantly differ in the distribution of comorbid conditions. We found that among the patients with OSA, 63% had noncalcified/mixed plaques, as opposed to 16% in the non‐OSA group (P < 0.0001), with unadjusted odds ratio of 9.3 (3.0, 28.4). After adjustment for other risk factors such as age, sex, race, hypercholesterolemia, and history of smoking, the association remained strong, with an odds ratio of 7.0 (1.9, 26.5; P < 0.05).Conclusions:Our study finds that the frequency of noncalcified/mixed plaques is much higher in patients with OSA than in non‐OSA patients. Patients with OSA also have more severe stenosis and a higher number of vessels involved. This study adds to a growing body of data regarding our understanding of the association of OSA and atherosclerosis.Dr. Sharma, Dr. Schoepf, Mr. Parker, Mr. Abro, and Mr. Armstrong contributed to data collection and analysis, drafting of the manuscript, and final approval. Dr. Gebregziabher contributed to data analysis, drafting of the manuscript, and final approval. Dr. Sharma had access to and takes responsibility for the integrity of the data and the accuracy of the data analysis.The authors of this manuscript have certified that they comply with the principles of ethical publishing (Shewan LG, Coats AJ. Ethics in the authorship and publishing of scientific articles. Int J Cardiol. 2010;144:1‐2.).The authors have no funding, financial relationships, or conflicts of interest to disclose.
Photoluminescent hierarchical Zno micro‐flower and its surface wettability
Authors: Ji X. B. , Lu W. C. , Ma H. P. 
Published: September 2012

AbstractThe flower‐like ZnO with micro‐nano hierarchical structure is successfully obtained by a simple hydrothermal synthesis, using sodium dodecyl benzene sulfonate (SDBS) as a structure direct agent. The resulted ZnO micro‐flowers are very uniform in morphology with particle sizes around 1 µm. A number of techniques, including X‐ray diffraction (XRD), field emission scan electron microscopy (FESEM), energy‐dispersive spectroscopy (EDS), fourier transform infrared (FTIR) spectra and thermogravimetry analysis (TGA), are used to characterize the obtained ZnO. The self‐assemble of ZnO nano‐sheets under the direction of SDBS leads to the formation of ZnO micro‐flowers. The room temperature photoluminescence property of the obtained flower‐like ZnO exhibits a broad visible light emission. The surface of as‐made ZnO shows a very hydrophilic property, while the special micro‐nano hierarchical structure enables the ZnO micro‐flower a superhydrophobic surface after modification of fluoroalkylsilane.