bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the venous pole of the heart in the frog Xenopus laevis: A morphological study with special focus on the development of the venoatrial connections
Authors: Jahr Maike , Männer Jörg 
Published: March 2011

AbstractThe heart of lung‐breathing vertebrates normally shows an asymmetric arrangement of its venoatrial connections along the left‐right (L‐R) body axis. The systemic venous tributaries empty into the right atrium while the pulmonary venous tributaries empty into the left atrium. The ways by which this asymmetry evolves from the originally symmetrically arranged embryonic venous heart pole are poorly defined. Here we document the development of the venous heart pole in Xenopus laevis (stages 40–46). We show that, prior to the appearance of the mouth of the common pulmonary vein (MCPV), the systemic venous tributaries empty into a bilaterally symmetric chamber (sinus venosus) that is demarcated from the developing atriums by a circular ridge of tissue (sinu‐atrial ridge). A solitary MCPV appears during stage 41. From the time point of its first appearance onwards, the MCPV lies cranial to the sinu‐atrial ridge and to the left of the developing interatrial septum and body midline. L‐R lineage analysis shows that the interatrial septum and MCPV both derive from the left body half. The CPV, therefore, opens from the beginning into the future left atrium. The definitive venoatrial connections are established by the formation of a septal complex that divides the lumen of the venous heart pole into systemic and pulmonary venous flow pathways. This complex arises from the anlage of the interatrial septum and the left half of the sinu‐atrial ridge. Developmental Dynamics 240:1518–1527, 2011. © 2011 Wiley‐Liss, Inc.
DFT Study on Alkyl‐ and Haloborylene Complexes of Manganese and Rhenium: Structure and Bonding Energy Analysis in [(η5‐C5H5)(CO)2M(BR)] and [(η5‐C5H5)(CO)2M(BX)] (M = Mn, Re; R = Me, Et, iPr, tBu; X = F, Cl, Br, I)
Authors: Pandey Krishna K. , Braunschweig Holger , Dewhurst Rian D. 
Published: March 2011

AbstractElectronic, molecular structures, and bonding analysis of the terminal neutral alkylborylene and haloborylene complexes of manganese and rhenium [(η5‐C5H5)(CO)2M(BR)] and [(η5‐C5H5)(CO)2M(BX)] (M = Mn, Re; R = Me, Et, iPr, tBu; X = F, Cl, Br, I) were investigated at the DFT/BP86/TZ2P level of theory. The calculated geometry of the manganese alkylborylene complex [(η5‐C5H5)(CO)2Mn(BtBu)] is in excellent agreement with the experimentally derived structural data. Pauling bond order of the optimized structures shows that the M–B bonds in these complexes are almost M=B double bonds, which is also supported by the performed energy decomposition analysis. The orbital interactions between the metal and boron arise mainly from M←BR σ donation, while the π bonding contribution is relatively small (22.6–25.8 % of total orbital contributions). The M–B π bond orbitals are highly polarized towards the metal atom and the contributions of boron are very small. In the BX ligands, σ bonding, interaction energies, electrostatic interactions and bond dissociation energies are smaller than those in the BR ligands. The contributions of the electrostatic interactionsΔEelstat are significantly larger in all borylene complexes than the covalent bonding ΔEorb: the [M]=BR bonding in the alkylborylene and haloborylene complexes has a greater degree of ionic character (ca. 61.7 % for the complexes I–IV, ca. 65.7 % for the complexes V–VIII, 53.9–56.2 % for the complexes IX–XII and 58.5–60.4 % for the complexes XIII–XVI). The chloroborylene complexes [(η5‐C5H5)(CO)2M(BCl)] possess the highest electrostatic interactions, ΔEelstat of all haloborylene complexes [(η5‐C5H5)(CO)2M(BX)], whereas the iodoborylene complexes [(η5‐C5H5)(CO)2M(BI)] display the highest orbital interactions, ΔEorb. The dimerization of the terminal borylene complex [(η5‐C5H5)(CO)2Mn(BCl)] to [{(η5‐C5H5)(CO)2Mn}2(η:η:μ‐B2Cl2)] is a strongly exothermic process (21.04 kcal/mol below the starting monomers) and the energies are in favor of a dimerization reaction.
Synthesis, Spectroscopic and Structural Studies on Vanadium(V) Periodates
Authors: Hector Andrew L. , Levason William 
Published: March 2011

AbstractReactions of V2O5 or NH4VO3 with periodic acid under basic conditions followed by acidification result in precipitates of general formula M5V4I2O19(OH)·nH2O (M = Na, n = 10; M = K, n = 5; M = Rb, n = 4; M = Cs, n = 3; M = NH4, n = 11). These are amorphous, and attempts at crystallisation failed, but spectroscopic measurements and analysis show similar features and compositions throughout this series of compounds. V and I K‐edge extended X‐ray absorption fine structure (EXAFS) spectra show a polymeric structure containing edge‐linked octahedral periodate and square‐pyramidal vanadyl groups.
Numerical analysis of a synthetic jet using an automated adaptive method
Authors: Chila Ronald J. , Kaminski Deborah A. 
Published: March 2011

SUMMARYAn automated adaptive remeshing methodology is applied to a synthetic jet. A set of two‐dimensional, axisymmetric, time‐dependent Computational Fluid Dynamics analyses are performed. Grid independence is achieved via successive levels of adaptive refinement using a novel methodology. The method employs adaptive remeshing, performed in an automated fashion. Adaptation criteria are based upon the undivided differences in select field variables. Sensors are placed at strategic locations within the flow field, which are used to aid in judging grid independence. The resulting analytical predictions are compared to an experimental dataset. The automated methodology yields both a verified and validated set of analysis results for the synthetic jet. Copyright © 2011 John Wiley & Sons, Ltd.
Differentiation of induced pluripotent stem cells into functional oligodendrocytes
Authors: Czepiel Marcin , Balasubramaniyan Veerakumar , Schaafsma Wandert , Stancic Mirjana , Mikkers Harald , Huisman Christian , Boddeke Erik , Copray Sjef 
Published: March 2011

AbstractThe technology to generate autologous pluripotent stem cells (iPS cells) from almost any somatic cell type has brought various cell replacement therapies within clinical research. Besides the challenge to optimize iPS protocols to appropriate safety and GMP levels, procedures need to be developed to differentiate iPS cells into specific fully differentiated and functional cell types for implantation purposes. In this article, we describe a protocol to differentiate mouse iPS cells into oligodendrocytes with the aim to investigate the feasibility of IPS stem cell‐based therapy for demyelinating disorders, such as multiple sclerosis. Our protocol results in the generation of oligodendrocyte precursor cells (OPCs) that can develop into mature, myelinating oligodendrocytes in‐vitro (co‐culture with DRG neurons) as well as in‐vivo (after implantation in the demyelinated corpus callosum of cuprizone‐treated mice). We report the importance of complete purification of the iPS‐derived OPC suspension to prevent the contamination with teratoma‐forming iPS cells. © 2011 Wiley‐Liss, Inc.
Expression of the voltage‐ and Ca2+‐dependent BK potassium channel subunits BKβ1 and BKβ4 in rodent astrocytes
Authors: Seidel Katharina N. , Derst Christian , Salzmann Mikhail , HöLtje Markus , Priller Josef , Markgraf René , Heinemann Stefan H. , Heilmann Heike , Skatchkov Serguei N. , Eaton Misty J. , Veh RüDiger W. , Prüss Harald 
Published: March 2011

AbstractLarge‐conductance Ca2+‐activated (BK) potassium channels are centrally involved in neurovascular coupling, immunity, and neural transmission. The ability to be synergistically activated by membrane depolarization, different ligands and intracellular Ca2+ links intracellular signaling and membrane excitability. The diverse physiological functions of BK channels crucially depend on regulatory β subunits. Although first studies characterized the neuronal distribution of BKβ subunits in the rodent brain, it is largely unknown which β subunit proteins are expressed in astrocytes and thus mediate these regulatory effects. We therefore analyzed the expression of BKβ subunits in rat and mouse brain and glial cell cultures. A monospecific polyclonal antibody against the BKβ4 channel subunit was raised, affinity‐purified and extensively characterized. BKβ4 and to a lesser degree BKβ1 transcripts and protein were detected in several astrocytic populations and cultured cells. Particularly strong BKβ4 immunostaining was detected in astrocytic progenitors derived from the subventricular zone. The overlapping expression of BKα and BKβ4 in astrocytes implies a functional relationship and suggests that BKβ4 is an important accessory β subunit for astrocytic BK channels. In addition, BKβ4 might exert effects independent of the α subunit as functional heterologous co‐expression of Nav1.6 and BKβ4 resulted in reduced Nav1.6 sodium currents. Thus, BKβ4 expression in astrocytes likely participates in regulating astrocytic voltage gradients and maintaining K+ homeostasis, hence enabling astrocytes to fulfill their complex regulatory influence on proper brain function. © 2011 Wiley‐Liss, Inc.
Hepcidin directly inhibits transferrin receptor 1 expression in astrocytes via a cyclic AMP‐protein kinase a pathway
Authors: Du Fang , Qian Christopher , Ming Qian Zhong , Wu Xiao‐Mei , Xie Hui , Yung Wing‐Ho , Ke Ya 
Published: March 2011

AbstractHepcidin, an iron‐regulatory hormone, plays a central role in iron homeostasis in peripheral tissues. The widespread distribution of hepcidin in the brain implies that the hormone may be essential for brain iron homeostasis. Here, we investigated the effects of hepcidin on the expression of iron uptake proteins, including transferrin receptor 1 (TfR1) and divalent metal transporter1 (DMT1) and the release protein ferroportin1 (Fpn1) in the cultured astrocytes. The effects of hepcidin on iron uptake, including transferrin‐bound iron (Tf‐Fe) and non‐transferrin‐bound iron (NTBI), and iron release were also studied. Our results demonstrated that astrocytes, when treated with hepcidin peptide or infected with hepcidin expression adenovirus (ad‐hepcidin), showed a significant ability in reducing iron uptake (both Tf‐Fe and NTBI), and iron release, which were accompanied by decreased expressions of TfR1, DMT1, and Fpn1. Moreover, we found that the effect of hepcidin in reducing TfR1 expression, which is dependent on the cyclic AMP–protein kinase A pathway, was the primary and dominant event. In conclusion, our results demonstrated that hepcidin controlled iron uptake and release by regulating expression of iron transport proteins. The findings also implied the existence of a novel hepcidin‐receptor on the membrane of astrocytes. © 2011 Wiley‐Liss, Inc.
HIV‐1 gp120 enhances outward potassium current via CXCR4 and cAMP‐dependent protein kinase a signaling in cultured rat microglia
Authors: Xu Changshui , Liu Jianuo , Chen Lina , Liang Shangdong , Fujii Nobutaka , Tamamura Hirokazu , Xiong Huangui 
Published: March 2011

AbstractMicroglia are critical cells in mediating the pathophysiology of neurodegenerative disorders such as HIV‐associated neurocognitive disorders. We hypothesize that HIV‐1 glycoprotein 120 (gp120) activates microglia by enhancing outward K+ currents, resulting in microglia secretion of neurotoxins, consequent neuronal dysfunction, and death. To test this hypothesis, we studied the effects of gp120 on outward K+ current in cultured rat microglia. Application of gp120 enhanced outward K+ current in a dose‐dependent manner, which was blocked by voltage‐gated K+ (Kv) channel blockers. Western blot analysis revealed that gp120 produced an elevated expression of Kv channel proteins. Examination of activation and inactivation of outward K+ currents showed that gp120 shifted membrane potentials for activation and steady‐state inactivation. The gp120‐associated enhancement of outward K+ current was blocked by either a CXCR4 receptor antagonist T140 or a specific protein kinase A (PKA) inhibitor H89, suggesting the involvement of chemokine receptor CXCR4 and PKA in gp120‐mediated enhancement of outward K+ current. Biological significance of gp120‐induced enhancement of microglia outward K+ current was demonstrated by experimental results showing the neurotoxic activity of gp120‐stimulated microglia, evaluated by TUNEL staining and MTT assay, significantly attenuated by Kv channel blockers. Taken together, these results suggest that gp120 induces microglia neurotoxic activity by enhancing microglia outward K+ current and that microglia Kv channels may function as a potential target for the development of therapeutic strategies. © 2011 Wiley‐Liss, Inc.
Levodopa and the feedback process on set‐shifting in parkinson's disease
Authors: Au Wing Lok , Zhou Juan , Palmes Paulito , Sitoh Yih‐Yian , Tan Louis CS , Rajapakse Jagath C 
Published: March 2011

AbstractObjective: To study the interaction between levodopa and the feedback process on set‐shifting in Parkinson's disease (PD). Methods: Functional magnetic resonance imaging (fMRI) studies were performed on 13 PD subjects and 17 age‐matched healthy controls while they performed a modified card‐sorting task. Experimental time periods were defined based on the types of feedback provided. PD subjects underwent the fMRI experiment twice, once during “off” medication (PDoff) and again after levodopa replacement (PDon). Results: Compared with normal subjects, the cognitive processing times were prolonged in PDoff but not in PDon subjects during learning through positive outcomes. The ability to set‐shift through negative outcomes was not affected in PD subjects, even when “off” medication. Intergroup comparisons showed the lateral prefrontal cortex was deactivated in PDoff subjects during positive feedback learning, especially following internal feedback cues. The cortical activations were increased in the posterior brain regions in PDoff subjects following external feedback learning, especially when negative feedback cues were provided. Levodopa replacement did not completely restore the activation patterns in PD subjects to normal although activations in the corticostriatal loops were restored. Conclusion: PD subjects showed differential ability to set‐shift, depending on the dopamine status as well as the types of feedback cues provided. PD subjects had difficulty performing set‐shift tasks through positive outcomes when “off” medication, and showed improvement after levodopa replacement. The ability to set‐shift through negative feedback was not affected in PD subjects even when “off” medication, possibly due to compensatory changes outside the nigrostriatal dopaminergic pathway. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Effects of attentional load on early visual processing depend on stimulus timing
Authors: Rauss Karsten , Pourtois Gilles , Vuilleumier Patrik , Schwartz Sophie 
Published: March 2011

AbstractA growing number of studies suggest that early visual processing is not only affected by low‐level perceptual attributes but also by higher order cognitive factors such as attention or emotion. Using high‐density electroencephalography, we recently demonstrated that attentional load of a task at fixation reduces the response of primary visual cortex to irrelevant peripheral stimuli, as indexed by the C1 component. In the latter study, peripheral stimuli were always presented during intervals without task‐relevant stimuli. Here, we use a similar paradigm but present central task stimuli and irrelevant peripheral stimuli simultaneously while keeping all other stimulus characteristics constant. Results show that rather than to suppress responses to peripheral stimulation, high attentional load elicits higher C1 amplitudes under these conditions. These findings suggest that stimulus timing can profoundly alter the effects of attentional load on the earliest stages of processing in human visual cortex. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Inconsistency and uncertainty of the human visual area loci following surface‐based registration: Probability and Entropy Maps
Authors: Yamamoto Hiroki , Fukunaga Masaki , Takahashi Shigeko , Mano Hiroaki , Tanaka Chuzo , Umeda Masahiro , Ejima Yoshimichi 
Published: March 2011

AbstractHere we created two different multisubject maps (16 subjects) to characterize interindividual variability in the positions of human visual areas (V1, dorsal and ventral parts of V2/3, V3A, V3B, V7, LOc, MT+, and hV4 [or V4v and V8]), which were localized using fMRI and coregistered using a surface‐based method. The first is a probability map representing the degree of alignment inconsistency for each area, in which each point in space is associated with the probability affiliated with a given area. The second, a novel map termed an entropy map in which each point is associated with Shannon entropy computed from the probabilities, represents the degree of uncertainty regarding the area that resides there, and is maximal when all areas are equally probable. The overall average probability and entropy values were about 0.27 and 1.15 bits, respectively, with dependencies on the visual areas. The probability and entropy maps generated here will benefit any application which requires predictions of areas that are most likely present at an anatomical point and know the uncertainty associated with such predictions. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Staying responsive to the world: Modality‐specific and ‐nonspecific contributions to speeded auditory, tactile, and visual stimulus detection
Authors: Langner Robert , Kellermann Thilo , Eickhoff Simon B. , Boers Frank , Chatterjee Anjan , Willmes Klaus , Sturm Walter 
Published: March 2011

AbstractSustained responsiveness to external stimulation is fundamental to many time‐critical interactions with the outside world. We used functional magnetic resonance imaging during speeded stimulus detection to identify convergent and divergent neural correlates of maintaining the readiness to respond to auditory, tactile, and visual stimuli. In addition, using a multimodal condition, we investigated the effect of making stimulus modality unpredictable. Relative to sensorimotor control tasks, all three unimodal detection tasks elicited stronger activity in the right temporo‐parietal junction, inferior frontal cortex, anterior insula, dorsal premotor cortex, and anterior cingulate cortex as well as bilateral mid‐cingulum, midbrain, brainstem, and medial cerebellum. The multimodal detection condition additionally activated left dorsal premotor cortex and bilateral precuneus. Modality‐specific modulations were confined to respective sensory areas: we found activity increases in relevant, and decreases in irrelevant sensory cortices. Our findings corroborate the modality independence of a predominantly right‐lateralized core network for maintaining an alert (i.e., highly responsive) state and extend previous results to the somatosensory modality. Monitoring multiple sensory channels appears to induce additional processing, possibly related to stimulus‐driven shifts of intermodal attention. The results further suggest that directing attention to a given sensory modality selectively enhances and suppresses sensory processing—even in simple detection tasks, which do not require inter‐ or intra‐modal selection. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Different structural correlates for verbal memory impairment in temporal lobe epilepsy with and without mesial temporal lobe sclerosis
Authors: Mueller Susanne G. , Laxer Kenneth D. , Scanlon Cathy , Garcia Paul , McMullen William J. , Loring David W. , Meador Kimford J. , Weiner Michael W. 
Published: March 2011

AbstractObjectives: Memory impairment is one of the most prominent cognitive deficits in temporal lobe epilepsy (TLE). The overall goal of this study was to explore the contribution of cortical and hippocampal (subfield) damage to impairment of auditory immediate recall (AIMrecall), auditory delayed recall (ADMrecall), and auditory delayed recognition (ADMrecog) of the Wechsler Memory Scale III (WMS‐III) in TLE with (TLE–MTS) and without hippocampal sclerosis (TLE‐no). It was hypothesized that volume loss in different subfields determines memory impairment in TLE–MTS and temporal neocortical thinning in TLE‐no. Methods: T1 whole brain and T2‐weighted hippocampal magnetic resonance imaging and WMS‐III were acquired in 22 controls, 18 TLE–MTS, and 25 TLE‐no. Hippocampal subfields were determined on the T2 image. Free surfer was used to obtain cortical thickness averages of temporal, frontal, and parietal cortical regions of interest (ROI). MANOVA and stepwise regression analysis were used to identify hippocampal subfields and cortical ROI significantly contributing to AIMrecall, ADMrecall, and ADMrecog. Results: In TLE–MTS, AIMrecall was associated with cornu ammonis 3 (CA3) and dentate (CA3&DG) and pars opercularis, ADMrecall with CA1 and pars triangularis, and ADMrecog with CA1. In TLE‐no, AIMrecall was associated with CA3&DG and fusiform gyrus (FUSI), and ADMrecall and ADMrecog were associated with FUSI. Conclusion: The study provided the evidence for different structural correlates of the verbal memory impairment in TLE–MTS and TLE‐no. In TLE–MTS, the memory impairment was mainly associated by subfield‐specific hippocampal and inferior frontal cortical damage. In TLE‐no, the impairment was associated by mesial–temporal cortical and to a lesser degree hippocampal damage. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
High‐risk human papillomavirus and cervical lymph node metastasis in patients with oropharyngeal cancer
Authors: Joo Young‐Hoon , Jung Chan‐Kwon , Sun Dong‐Il , Park Jun‐Ook , Cho Kwang‐Jae , Kim Min‐Sik 
Published: March 2011

AbstractBackgroundThe purpose of this study was to determine the role of high‐risk human papillomavirus (HPV) in lymph node metastasis and the depth of invasion in oropharyngeal cancer.MethodsThe study included patients with 90 oral carcinomas and 66 oropharyngeal carcinomas. High‐risk HPV in situ hybridization was performed to detect HPV infection.ResultsThe positive rate of high‐risk HPV in situ hybridization was 15.4% (24 of 156). There was a significant difference in the fraction of positive high‐risk HPV between oral (6.7%) and oropharyngeal (27.3%) cancers (p < .000). Significant correlations were found between positive high‐risk HPV and cervical lymph node metastasis, tumor depth of invasion in patients with oropharyngeal cancer (p = .002, p = .016, respectively). There was a statistically significant association between high‐risk HPV positivity and the disease‐specific survival in patients with oropharyngeal cancer (p = .035).ConclusionHigh‐risk HPV infection was significantly related to cervical lymph node metastasis and depth of invasion in patients with oropharyngeal cancer. © 2011 Wiley Periodicals, Inc. Head Neck, 2012