bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid full‐brain fMRI with an accelerated multi shot 3D EPI sequence using both UNFOLD and GRAPPA
Authors: Afacan Onur , Hoge W. Scott , Janoos Firdaus , Brooks Dana H. , Morocz Istvan A 
Published: November 2011

AbstractThe desire to understand complex mental processes using functional MRI drives development of imaging techniques that scan the whole human brain at a high spatial and temporal resolution. In this work, an accelerated multishot three‐dimensional echo‐planar imaging sequence is proposed to increase the temporal resolution of these studies. A combination of two modern acceleration techniques, UNFOLD and GRAPPA is used in the secondary phase encoding direction to reduce the scan time effectively. The sequence (repetition time of 1.02 s) was compared with standard two‐dimensional echo‐planar imaging (3 s) and multishot three‐dimensional echo‐planar imaging (3 s) sequences with both block design and event‐related functional MRI paradigms. With the same experimental setup and imaging time, the temporal resolution improvement with our sequence yields similar activation regions in the block design functional MRI paradigm with slightly increased t‐scores. Moreover, additional information on the timing of rapid dynamic changes was extracted from accelerated images for the case of the event related complex mental paradigm. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Simultaneous Determination of Four Sesquiterpenoids in Atractylodes Macrocephala Rhizoma by GC‐FID: Optimisation of an Ultrasound‐assisted Extraction by Central Composite Design
Authors: Shi Yang‐Yang , Guan Shu‐Hong , Tang Ren‐Neng , Tao Si‐Jia , Guo De‐An 
Published: November 2011

ABSTRACTIntroductionAtractylodes Macrocephala Rhizoma (AMR) is a traditional Chinese medicine containing several sesquiterpenoids with a series of effects. These bioactive compounds may be used as chemical markers for the quality control of AMR. It is necessary to optimise the extraction method and conditions in order to improve extraction productivity.ObjectiveTo develop a simple and effective method for the extraction of sesquiterpenoids from AMR and then to simultaneously determine four sesquiterpenoids, selina‐4 (14), 7(11)‐dien‐8‐one (SA), atractylenolide II (AII), atractylenolide III (AIII) and atractylenolide VII (AVII), in AMR.MethodologyUltrasound‐assisted extraction (UAE) was optimised by central composite design (CCD) to obtain the maximum efficiency. The gas chromatography method was validated and applied for the quantification of four sesquiterpenoids.ResultsThe optimum values of factors were: particle size (120 mesh), extraction time (26 min), extraction temperature (39°C) and 31 mL of chloroform. The selectivity, linear range, limits of detection (LOD) and quantification (LOQ), accuracy, precision and repeatability of the method developed indicated its validity. The application of the method showed that the contents of four sesquiterpenoids in AMR were rather variable.ConclusionThe results indicated that the described GC method could be used for the quality control of AMR and its related preparations. Meanwhile, this research revealed that UAE under optimum conditions could be considered as a powerful tool for the extraction of phytochemicals from plants. Copyright © 2011 John Wiley & Sons, Ltd.
Ribonuclease A suggests how proteins self‐chaperone against amyloid fiber formation
Authors: Teng Poh K. , Anderson Natalie J. , Goldschmidt Lukasz , Sawaya Michael R. , Sambashivan Shilpa , Eisenberg David 
Published: November 2011

AbstractGenomic analyses have identified segments with high fiber‐forming propensity in many proteins not known to form amyloid. Proteins are often protected from entering the amyloid state by molecular chaperones that permit them to fold in isolation from identical molecules; but, how do proteins self‐chaperone their folding in the absence of chaperones? Here, we explore this question with the stable protein ribonuclease A (RNase A). We previously identified fiber‐forming segments of amyloid‐related proteins and demonstrated that insertion of these segments into the C‐terminal hinge loop of nonfiber‐forming RNase A can convert RNase A into the amyloid state through three‐dimensional domain‐swapping, where the inserted fiber‐forming segments interact to create a steric zipper spine. In this study, we convert RNase A into amyloid‐like fibers by increasing the loop length and hence conformational freedom of an endogenous fiber‐forming segment, SSTSAASS, in the N‐terminal hinge loop. This is accomplished by sandwiching SSTSAASS between inserted Gly residues. With these inserts, SSTSAASS is now able to form the steric zipper spine, allowing RNase A to form amyloid‐like fibers. We show that these fibers contain RNase A molecules retaining their enzymatic activity and therefore native‐like structure. Thus, RNase A appears to prevent fiber formation by limiting the conformational freedom of this fiber‐forming segment from entering a steric zipper. Our observations suggest that proteins have evolved to self‐chaperone by using similar protective mechanisms.
Optical anisotropy of a‐plane Al0.8In0.2N grown on an a‐plane GaN pseudosubstrate
Authors: Sakalauskas E. , Wieneke M. , Dadgar A. , Gobsch G. , Krost A. , Goldhahn R. 
Published: November 2011

AbstractThe optical properties of a‐plane Al1−xInxN grown by metal‐organic vapor phase epitaxy on an a‐plane GaN/r‐plane sapphire template are reported. X‐ray diffraction yielded an In content of ∼20%. The ordinary and extraordinary dielectric functions (DFs) were obtained by spectroscopic ellipsometry in the spectral range from 1 eV up to 6 eV at room temperature. By fitting the experimentally obtained complex DF, the inter‐band transitions EA and EB, which are allowed for configurations ${\bf E}\bot {\bf c}$ and ${\bf E}||{\bf c}$, respectively, were determined. A redshift of ∼200 meV is found for the transition EB with respect to transition EA attributed to the optical selection rules. Furthermore, the ordinary and extraordinary refractive indices in the transparent region (below the band gap) are represented in the analytical form. The AlInN alloy shows the positive birefringence and the difference between the extraordinary and ordinary refractive index ne − no is defined to be 0.068 at photon energy of 3 eV. Finally, the ordinary and extraordinary high‐energy dielectric constants were estimated.
Infrared photoluminescence of high In‐content InN/InGaN multiple‐quantum‐wells
Authors: Valdueza‐Felip Sirona , Rigutti Lorenzo , Naranjo Fernando B. , Lacroix Bertrand , Fernández Susana , Ruterana Pierre , Julien François H. , González‐Herráez Miguel , Monroy Eva 
Published: November 2011

AbstractWe report on the thermal evolution of the photoluminescence (PL) from high In‐content InN/In0.9Ga0.1N multiple‐quantum wells (MQWs) synthesized by plasma‐assisted molecular‐beam epitaxy on GaN‐on‐sapphire templates. The structural quality and the well/barrier thickness uniformity in the MQW structure are assessed by X‐ray diffraction and transmission electron microscopy measurements. PL results are compared with the luminescence from a 1‐µm‐thick InN reference sample. In both cases, the dominant low‐temperature (5 K) PL emission peaks at ∼0.73 eV with a full width at half maximum of ∼86 meV. The InN layer displays an S‐shape evolution of the emission peak energy with temperature, explained in terms of carrier localization. A carrier localization energy of ∼12 meV is estimated for the InN layer, in good agreement with the expected carrier concentration. In the case of the MQW structure, an enhancement of the carrier localization associated to the piezoelectric field results in an improved thermal stability of the PL intensity, reaching an internal quantum efficiency of ∼16%.
Infrared phonon modes and dielectric properties of La2Zr2O7: Comparing thin film to bulk material
Authors: Cheng Xuerui , Qi Zeming , Li Tingting , Zhang Guobin , Li Chengxiang , Zhou Hongjun , Wang Yuyin , Yin Min 
Published: November 2011

AbstractThe infrared phonon modes and dielectric constants of bulk and thin film of La2Zr2O7 are studies by infrared spectroscopy. The infrared response of the La2Zr2O7 bulk sample is determined by seven infrared phonon modes. The obtained static dielectric constant is 22.8 and the largest contribution is from the phonon modes at 213.7 and 352.7 cm−1. Compared to the bulk sample, the obtained dielectric constant of the La2Zr2O7 thin film shows an obvious decrease. The loss of the dielectric constant is due to the absence and weakness of some phonon modes in the thin film, even though it still preserves two important modes, mentioned above. The result indicates that the disorder in the La2Zr2O7 thin film has an important influence on the dielectric property.
High quality GaAs quantum nanostructures grown by droplet epitaxy on Ge and Ge‐on‐Si substrates
Authors: Bietti Sergio , Cavigli Lucia , Abbarchi Marco , Vinattieri Anna , Gurioli Massimo , Fedorov Alexey , Cecchi Stefano , Isa Fabio , Isella Giovanni , Sanguinetti Stefano 
Published: November 2011

AbstractWe report on the growth and optical characterization by macro and micro photoluminescence measurements of high optical quality GaAs quantum nanostructures grown by droplet epitaxy on Ge and Si substrates. The quantum nanostructures show optical performances comparable to those achievable with the most advanced realized on GaAs substrates.The adopted growth procedures show also the possibility to fabricate the active layer maintaining a low thermal budget compatible with back‐end integration of the fabricated materials on integrated circuits. We demonstrate the possibility to embed GaAs nanostructured devices such as intersubband detectors and single quantum emitters on Si substrates. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular characteristics of native sago starch and isolated fractions determined using asymmetrical flow field‐flow fractionation
Authors: Juna Shazia , Huber Anton ,   Member of EPNOE – European Polysaccharide Network of Excellence
Published: November 2011

AbstractThe apparent average molar masses (Mw,app), apparent average radii of gyration (Rg,app), of native sago starch and fractions were determined using asymmetrical flow field‐flow fractionation coupled with multi‐angle light scattering and refractive index detectors (AF4/MALS/RI). Amylose‐type (Fraction A) and amylopectin‐type (Fraction B) were chemically separated from native sago starch. Native sago starch and Fractions (A–B) were dissolved in 1M KSCN using a high pressure microwave vessel. The effect of varying cross flow rates at a fixed channel flow rate upon the Mw,app and Rg,app distributions of native sago starch and Fractions (A–B) were investigated. The average Mw,app values of native sago starch, Fraction (A) and Fraction (B) were 60 × 106, 1.5 × 106 and 60 × 106 g/mol, respectively, with average Rg,app values of 142, 75 and 127 nm, respectively. The sphere‐equivalent hydrodynamic radii (Rh) values for native sago starch and fractions were determined from AF4 experimental parameters.
Localized delay‐bounded and energy‐efficient data aggregation in wireless sensor and actor networks
Authors: Li Xu , Yan Shuo , Xu Chendong , Nayak Amiya , Stojmenovic Ivan 
Published: November 2011

ABSTRACTIn data aggregation, sensor measurements from the whole sensory field or a sub‐field are collected as a single report at an actor by using aggregate functions such as sum, average, maximum, minimum, count, deviation, and so on. We propose a localized delay‐bounded and energy‐efficient data aggregation (DEDA) protocol for request‐driven wireless sensor networks with IEEE 802.11 carrier sense multiple access with collision avoidance run at media access control layer. This protocol uses a novel two‐stage delay model, which measures end‐to‐end delay by using either hop count or degree sum along a routing path depending on traffic intensity. It models the network as a unit disk graph (UDG) and constructs a localized minimal spanning tree (LMST) sub‐graph. Using only edges from LMST, it builds a shortest‐path (thus energy‐efficient) tree rooted at the actor for data aggregation. The tree is used without modification if it generates acceptable delay, compared with a given delay bound. Otherwise, it is adjusted by replacing LMST sub‐paths with UDG edges. The adjustment is done locally on the fly, according to the desired progress value computed at each node. We further propose to integrate DEDA with a localized sensor activity scheduling algorithm and a localized connected dominating set algorithm, yielding two DEDA variants, to improve its energy efficiency and delay reliability. Through an extensive set of simulation, we evaluate the performance of DEDA with various network parameters. Our simulation results indicate that DEDA far outperforms the only existing competing protocol. Copyright © 2011 John Wiley & Sons, Ltd.
Right hand, left brain: genetic and evolutionary bases of cerebral asymmetries for language and manual action
Authors: Corballis Michael C. , Badzakova‐Trajkov Gjurgjica , Häberling Isabelle S. 
Published: November 2011

AbstractMost people are right‐handed and left‐cerebrally dominant for language. This pattern of asymmetry, as well as departures from it, have been reasonably accommodated in terms of a postulated gene with two alleles, one disposing to this common pattern and the other leaving the direction of handedness and language asymmetry to chance. There are some leads as to the location of the gene or genes concerned, but no clear resolution; one possibility is that the chance factor is achieved by epigenetic cancelling of the lateralizing gene rather than through a chance allele. Neurological evidence suggests that the neural basis of manual praxis, including pantomime and tool use, is more closely associated with cerebral asymmetry for language than with handedness, and is homologous with the so‐called “mirror system” in the primate brain, which is specialized for manual grasping. The evidence reviewed supports the theory that language itself evolved within the praxic system, and became lateralized in humans, and perhaps to a lesser extent in our common ancestry with the great apes.WIREs Cogn Sci2012, 3:1–17. doi: 10.1002/wcs.158This article is categorized under:Psychology > Brain Function and Dysfunction
Self‐incompatibility in Petunia: a self/nonself‐recognition mechanism employing S‐locus F‐box proteins and S‐RNase to prevent inbreeding
Authors: Wang Ning , Kao Teh‐Hui 
Published: November 2011

AbstractMany flowering plants producing bisexual flowers have adopted self‐incompatibility (SI), a reproductive strategy which allows pistils to distinguish between self and nonself pollen, and to only permit nonself pollen to effect fertilization. To date, three different SI mechanisms have been identified, and this article focuses on the S‐RNase‐based mechanism using Petunia (Solanaceae) as a model. The genetic basis of this type of SI was established nearly a century ago; the polymorphic S‐locus specifies the genetic identity of pollen and the pistil. Molecular genetic studies carried out since the late 1980s have led to the identification of the polymorphic genes at the S‐locus that control self/nonself‐recognition between pollen and the pistil. The S‐RNase gene, which controls pistil specificity, was identified first, and subsequent sequencing of the S‐locus region containing S‐RNase led to the identification of the S‐locus F‐box (SLF) gene (now named SLF1). A transgenic approach was used to show that S2‐SLF1 (SLF1 of S2‐halotype) of Petunia inflata controls pollen specificity. The S‐locus contains additional pollen‐expressed F‐box genes that show sequence similarity with SLF1, and initially they were thought not to be involved in pollen specificity. However, further studies of SLF1 suggested that it is not the only pollen specificity gene. Indeed, it has recently been shown that two previously identified SLF‐like genes in P. inflata (now named SLF2 and SLF3) and a yet unknown number of additional SLF‐like genes (named SLF4, SLF5, etc.) collaboratively function to control pollen specificity. The significance and implications of this new finding are discussed. WIREs Dev Biol 2012, 1:267–275. doi: 10.1002/wdev.10This article is categorized under:

Plant Development > Fertilization, Embryogenesis, and Seed Development
Neural crest specification: tissues, signals, and transcription factors
Authors: Rogers C.D. , Jayasena C.S. , Nie S. , Bronner M.E. 
Published: November 2011

AbstractThe neural crest is a transient population of multipotent and migratory cells unique to vertebrate embryos. Initially derived from the borders of the neural plate, these cells undergo an epithelial to mesenchymal transition to leave the central nervous system, migrate extensively in the periphery, and differentiate into numerous diverse derivatives. These include but are not limited to craniofacial cartilage, pigment cells, and peripheral neurons and glia. Attractive for their similarities to stem cells and metastatic cancer cells, neural crest cells are a popular model system for studying cell/tissue interactions and signaling factors that influence cell fate decisions and lineage transitions. In this review, we discuss the mechanisms required for neural crest formation in various vertebrate species, focusing on the importance of signaling factors from adjacent tissues and conserved gene regulatory interactions, which are required for induction and specification of the ectodermal tissue that will become neural crest. WIREs Dev Biol 2012, 1:52–68. doi: 10.1002/wdev.8This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Gene Networks and Genomics
Signaling Pathways > Cell Fate Signaling
Early Embryonic Development > Development to the Basic Body Plan
Quality control in tRNA charging
Authors: Jakubowski Hieronim 
Published: November 2011

AbstractFaithful translation of the genetic code during protein synthesis is fundamental to the growth, development, and function of living organisms. Aminoacyl‐tRNA synthetases (AARSs), which define the genetic code by correctly pairing amino acids with their cognate tRNAs, are responsible for ‘quality control’ in the flow of information from a gene to a protein. When differences in binding energies of amino acids to an AARS are inadequate, editing is used to achieve high selectivity. Editing occurs at the synthetic active site by hydrolysis of noncognate aminoacyl‐adenylates (pretransfer editing) and at a dedicated editing site located in a separate domain by deacylation of mischarged aminoacyl‐tRNA (posttransfer editing). Access of nonprotein amino acids, such as homocysteine or ornithine, to the genetic code is prevented by the editing function of AARSs, which functionally partitions amino acids present in living cells into protein and nonprotein amino acids. Continuous editing is part of the tRNA aminoacylation process in living organisms from bacteria to human beings. Preventing mistranslation by the clearance of misactivated amino acids is crucial to cellular homeostasis and has a role in etiology of disease. Although there is a strong selective pressure to minimize mistranslation, some organisms possess error‐prone AARSs that cause mistranslation. Elevated levels of mistranslation and the synthesis of statistical proteins can be beneficial for pathogens by increasing phenotypic variation essential for the evasion of host defenses. WIREs RNA 2012, 3:295–310. doi: 10.1002/wrna.122This article is categorized under:

RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution
Translation > Translation Mechanisms
RNA Processing > tRNA Processing
RNA in Disease and Development > RNA in Disease
Long‐Term Outcome in Patients with Primary Hyperparathyroidism who Underwent Minimally Invasive Parathyroidectomy
Authors: Venkat Raghunandan , Kouniavsky Guennadi , Tufano Ralph P. , Schneider Eric B. , Dackiw Alan P. B. , Zeiger Martha A. 
Published: November 2011

AbstractBackgroundMinimally invasive parathyroidectomy (MIP) has become a well‐accepted treatment for selected patients with primary hyperparathyroidism (PHPT). However, few studies have evaluated long‐term outcomes for this operative approach. We therefore chose to examine both the long‐term symptom resolution and biochemical cure following MIP for PHPT.MethodsA total of 460 PHPT patients who underwent a MIP between 2004 and 2009 were successfully mailed a questionnaire that assessed preoperative and postoperative Parathyroidectomy Assessment of Symptoms (PAS) scores, most recent calcium and parathyroid hormone (PTH) levels, and information about any reoperation for PHPT. Long‐term evaluation of symptomatic and biochemical cure was performed.ResultsA total of 200 patients (43.5%) responded to our correspondence. The mean age of the patients was 58.7 ± 11.9 years, 74.5% were female, and 78.5% were Caucasian. The mean follow‐up was 37 ± 19 months. The mean PAS scores fell by 117 ± 14 at long‐term follow‐up after MIP (P < 0.0001). All 13 symptoms comprising the PAS score diminished, of which ten did so significantly (P < 0.01). There was a significant drop in the mean serum calcium (preop. 11.1 mg/dl, postop. 9.6 mg/dl; P < 0.0001) and PTH (preop. 130.9 pg/ml, postop. 45.7 pg/ml; P < 0.0001) at long‐term follow‐up. Five patients (2.5%) developed recurrent disease (calcium > 10.5 mg/dl), and one (0.5%) underwent a reoperation for persistent disease and was subsequently cured.ConclusionsThis study demonstrates that MIP has long‐term benefits in terms of excellent symptom resolution and a high biochemical cure rate (97%) in selected patients who have PHPT, preoperative localization with sestamibi scans, and assessment of intraoperative PTH level.
Neighborhood Disorder and Children's Antisocial Behavior: The Protective Effect of Family Support Among Mexican American and African American Families
Authors: Schofield Thomas J. , Conger Rand D. , Conger Katherine J. , Martin Monica J. , Brody Gene , Simons Ronald , Cutrona Carolyn 
Published: November 2011

AbstractUsing data from a sample of 673 Mexican Origin families, the current investigation examined the degree to which family supportiveness acted as a protective buffer between neighborhood disorder and antisocial behavior during late childhood (i.e. intent to use controlled substances, externalizing, and association with deviant peers). Children's perceptions of neighborhood disorder fully mediated associations between census and observer measures of neighborhood disorder and their antisocial behavior. Family support buffered children from the higher rates of antisocial behavior generally associated with living in disorderly neighborhoods. An additional goal of the current study was to replicate these findings in a second sample of 897 African American families, and that replication was successful. These findings suggest that family support may play a protective role for children living in dangerous or disadvantaged neighborhoods. They also suggest that neighborhood interventions should consider several points of entry including structural changes, resident perceptions of their neighborhood and family support.