bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuronal and glial alterations, increased anxiety, and cognitive impairment before hippocampal amyloid deposition in PDAPP mice, model of Alzheimer's disease
Authors: Beauquis Juan , Vinuesa Angeles , Pomilio Carlos , Pavía Patricio , Galván Verónica , Saravia Flavia 
Published: October 2013

ABSTRACTIn the context of Alzheimer's disease (AD), hippocampal alterations have been well described in advanced stages of the pathology, when amyloid deposition, inflammation and glial activation occur, but less attention has been directed to studying early brain and behavioral changes. Using an animal model of AD, the transgenic PDAPP‐J20 mouse at 5 months of age, when no amyloid plaques are present and low cerebral levels of amyloid peptides are detectable, we found structural, morphological, and cellular alterations in the hippocampus. Young transgenic mice showed a reduced hippocampal volume with less number of pyramidal and granular neurons, which additionally exhibited cell atrophy. The neurogenic capability in this zone, measured as DCX+ cells, was strongly diminished and associated to alterations in cell maturity. A decrease in presynaptic synaptophysin optical density was detected in mossy fibers reaching CA3 subfield but not in Golgi stained‐ CA1 dendritic spine density. Employing confocal microscopy and accurate stereological tools we also found a reduction in the number of GFAP+ cells, along with decreased astrocyte complexity, suggesting a potential detriment of neural support. According with untimely neuroglial alterations, young PDAPP mice failed in the novel location recognition test, that depends on hippocampal function. Moreover, multivariate statistical analysis of the behavioral outcome in the open‐field test evidenced an elevated anxiety score in Tg mice compared with age‐matched control mice. In line with this, the transgenic group showed a higher number of c‐Fos+ nuclei in central and basolateral amygdala, a result that supports the early involvement of the emotionality factor in AD pathology. Applying an integrative approach, this work focuses on early structural, morphological and functional changes and provides new and compelling evidence of behavioral alterations that precede manifest AD. © 2013 Wiley Periodicals, Inc.
Early age‐dependent impairments of context‐dependent extinction learning, object recognition, and object‐place learning occur in rats
Authors: Wiescholleck Valentina , Emma André Marion Agnès , Manahan‐Vaughan Denise 
Published: October 2013

ABSTRACTThe hippocampus is vulnerable to age‐dependent memory decline. Multiple forms of memory depend on adequate hippocampal function. Extinction learning comprises active inhibition of no longer relevant learned information concurrent with suppression of a previously learned reaction. It is highly dependent on context, and evidence exists that it requires hippocampal activation. In this study, we addressed whether context‐based extinction as well as hippocampus‐dependent tasks, such as object recognition and object‐place recognition, are equally affected by moderate aging. Young (7‐8 week old) and older (7‐8 month old) Wistar rats were used. For the extinction study, animals learned that a particular floor context indicated that they should turn into one specific arm (e.g., left) to receive a food reward. On the day after reaching the learning criterion of 80% correct choices, the floor context was changed, no reward was given and animals were expected to extinguish the learned response. Both, young and older rats managed this first extinction trial in the new context with older rats showing a faster extinction performance. One day later, animals were returned to the T‐maze with the original floor context and renewal effects were assessed. In this case, only young but not older rats showed the expected renewal effect (lower extinction ratio as compared to the day before). To assess general memory abilities, animals were tested in the standard object recognition and object‐place memory tasks. Evaluations were made at 5 min, 1 h and 7 day intervals. Object recognition memory was poor at short‐term and intermediate time‐points in older but not young rats. Object‐place memory performance was unaffected at 5 min, but impaired at 1 h in older but not young rats. Both groups were impaired at 7 days. These findings support that not only aspects of general memory, but also context‐dependent extinction learning, are affected by moderate aging. This may reflect less flexibility in revising hard‐wired knowledge or reduced adaptability to new learning challenges. © 2013 Wiley Periodicals, Inc.
First Total Synthesis of (−)‐Ligustiphenol
Authors: Luo Huan , Liu Yanfei , Liang Dong , Hao Zhiyou , Wang Yan , Zhang Chunlei , Zhang Qingjian , Yu Dequan 
Published: October 2013

AbstractThe first asymmetric total synthesis of (−)‐ligustiphenol is reported. The key step was conducted by exploiting a steric hindrance effect to control the formation of the adduct in a nucleophilic α‐Li‐phenolate addition reaction to the intermediate α‐oxo (−)‐menthyl ester. The synthesis is concise and feasible for the construction of analogous compounds and investigation of their biological activity.
Divergent Enantioselective Total Synthesis of Siphonarienal, Siphonarienone, and Pectinatone
Authors: Yadav Jhillu Singh , Chary D. Narasimha , Yadav Nagendra Nath , Sengupta Sandip , Subba Reddy Basi V. 
Published: October 2013

AbstractA divergent synthesis of siphonarienal, siphonarienone, and pectinatone has been achieved from a common precursor 4, which was synthesized by using an enzymatic desymmetrization approach. The major key steps involved were Grignard reaction, Wittig reaction, Evans' asymmetric alkylation, and base‐catalyzed cyclization.
From Blue Azulenes to Blue Heptalenes – New Strongly Polarized π‐Convertible Heptalenes
Authors: Landmesser Thomas , Linden Anthony , Hansen Hans‐Jürgen 
Published: October 2013

AbstractThe 1,5,6,8,10‐pentamethylheptalene‐4‐carboxaldehyde (4b) (together with its double‐bond‐shifted (DBS) isomer 4a) and methyl 4‐formyl‐1,6,8,10‐tetramethylheptalene‐5‐carboxylate (15b) were synthesized (Schemes 3 and 7, resp.). Aminoethenylation of 4a/4b with N,N‐dimethylformamide dimethyl acetal (=1,1‐dimethoxy‐N,N‐dimethylmethanamine=DMFDMA) led in DMF to 1‐[(1E)‐2‐(dimethylamino)ethenyl]‐5,6,8,10‐tetramethylheptalene‐2‐carboxaldehyde (18a; Scheme 9), whereas the stronger aminoethenylation agent N,N,N′,N′,N″,N″‐hexamethylmethanetriamine (=tris(dimethylamino)methane=TDMAM) gave an almost 1 : 1 mixture of 18a and 1‐[(1E)‐2‐(dimethylamino)ethenyl]‐5,6,8,10‐tetramethylheptalene‐4‐carboxaldehyde (20b; Scheme 11). Carboxylate 15b delivered with DMFDMA on heating in DMF the expected aminoethenylation product 19b (Scheme 10). The aminoethenylated heptalenecarboxaldehydes were treated with malononitrile in CH2Cl2 in the presence of TiCl4/pyridine to yield the corresponding malononitrile derivatives 23b, 24b, and 26a (Schemes 13 and 14). The photochemically induced DBS process of the heptalenecarboxaldehydes as ‘soft’ merocyanines and their malononitrile derivatives as ‘strong’ merocyanines of almost zwitterionic nature were studied in detail (Figs. 10–29) with the result that 1,4‐donor/acceptor substituted heptalenes are cleaner switchable than 1,2‐donor/acceptor‐substituted heptalenes.
Formation of 2‐(Phenylsulfonyl)resorcinols (=2‐(Phenylsulfonyl)benzene‐1,3‐diols) from Symmetrically Substituted Maleic Anhydrides (=Furan‐2,5‐diones)
Authors: Abou‐Hadeed Khaled , Hansen Hans‐Jürgen 
Published: October 2013

AbstractTreatment of symmetrically substituted maleic anhydrides (=furan‐2,5‐diones) 6 with lithium (phenylsulfonyl)methanide, followed by methylation of the adduct with MeI/K2CO3 in acetone, give the corresponding 4,5‐disubstituted 2‐methyl‐2‐(phenylsulfonyl)cyclopent‐4‐ene‐1,3‐diones 8 (Scheme 3). Reaction of the latter with lithium (phenylsulfonyl)methanide in THF (−78°) and then with 4 mol‐equiv. BuLi (−5° to r.t.) leads to 5,6‐disubstituted 4‐methyl‐2‐(phenylsulfonyl)benzene‐1,3‐diols 9 (Scheme 4).
Constructing Graphs with No Immersion of Large Complete Graphs
Authors: Collins Karen L. , Heenehan Megan E. 
Published: October 2013

AbstractIn 1989, Lescure and Meyniel proved, for , that every d‐chromatic graph contains an immersion of , and in 2003 Abu‐Khzam and Langston conjectured that this holds for all d. In 2010, DeVos, Kawarabayashi, Mohar, and Okamura proved this conjecture for . In each proof, the d‐chromatic assumption was not fully utilized, as the proofs only use the fact that a d‐critical graph has minimum degree at least . DeVos, Dvořák, Fox, McDonald, Mohar, and Scheide show the stronger conjecture that a graph with minimum degree has an immersion of fails for and with a finite number of examples for each value of d, and small chromatic number relative to d, but it is shown that a minimum degree of 200d does guarantee an immersion of .In this paper, we show that the stronger conjecture is false for and give infinite families of examples with minimum degree and chromatic number , , or that do not contain an immersion of . Our examples can be up to ‐edge‐connected. We show that two of Hajós' operations preserve immersions of . We conclude with some open questions, and the conjecture that a 2‐edge‐connected graph G with minimum degree and more than vertices of degree at least has an immersion of .
Copy number variation of chikungunya ECSA virus with disease symptoms among Indian patients
Authors: Dutta Sudip Kumar , Pal Tithi , Saha Bibhuti , Mandal Syamsundar , Tripathi Anusri 
Published: October 2013

ABSTRACTAfter a gap of three decades, from 2005 onwards, a series of Chikungunya virus (CHIKV) outbreaks occurred worldwide. This study was performed to detect CHIKV infection, its genotype among symptomatic Eastern Indian patients and to analyze any association between the presence of CHIKV genome in patient body with appearance of disease symptoms (n = 199). Plasma‐extracted viral RNA was reverse transcribed to cDNA and PCR‐amplified followed by agarose gel electrophoresis. Viral load among CHIKV‐positive patients was determined by real time RT‐PCR. CHIKV‐IgM in sera was detected by ELISA. Sequencing and phylogenetic analysis of plasma‐extracted PCR products was done. CHIKV genome and IgM were detected among 65.3% (n = 130) and 41.2% (n = 82) patients respectively. Joint swelling was significantly associated with CHIKV infection (P‐value: 0.0003). CHIKV PCR positive patients were grouped in two categories: Group‐I: viral load <104 copies/ml and Group‐II: viral load ≥104 copies/ml. Higher number of acute stage patients clustered in Group‐II. Fever and joint swelling were significantly more prevalent among Group‐II patients, whereas rash and diarrhoea among Group‐I patients (P‐value <0.05). Patient‐isolated CHIKV sequences clustered with CHIKV ECSA genotypes in the phylogenetic tree, with two types of CHIKV strains found to circulate among them—as indicated by their different nucleotide sequences. This is the first study detecting the presence of CHIKV ECSA genotype among Eastern Indian patients. Fever and joint swelling might have appeared first followed by rash, diarrhea during disease progression—as indicated by CHIK viral load in patients. Thus, viral load can be used as unique diagnostic and prognostic marker of Chikungunya disease pathogenesis. J. Med. Virol. 86:1386–1392, 2014. © 2013 Wiley Periodicals, Inc.
Eemian and Early Weichselian environments in southern Sweden: a multi‐proxy study of till‐covered organic deposits from the Småland peneplain
Authors: LEMDAHL GEOFFREY , BROSTRÖM ANNA , HEDENÄS LARS , ARVIDSSON KRISTINA , HOLMGREN SOFIA , GAILLARD MARIE‐JOSÉ , MÖLLER PER 
Published: October 2013

ABSTRACTBased on their luminescence and infinite radiocarbon ages, organic deposits beneath till at two sites on the Småland peneplain, southern Sweden (Nybygget and Stora Gäddevik), are concluded to have formed before the Middle Weichselian. Applied palaeoecological methods include analyses of pollen, diatoms, charcoal fragments, macroscopic remains of vascular plants and mosses, and insect remains. Pollen‐stratigraphical correlations with previously studied interglacial/interstadial sites in southern Sweden, Denmark and northern Germany suggest that the peat at Nybygget dates from the Brørup interstadial or the final stage of the Eemian interglacial, whereas the lake sediments at Stora Gäddevik probably were emplaced during the middle Eemian. We conclude that the peat was formed in a wetland characterized by both wood swamp and open mire vegetation, and surrounded by semi‐open woodlands dominated by pine, birch and hazel. The middle Eemian sequence at the Stora Gäddevik site provides evidence of a moderately nutrient‐rich to nutrient‐rich lake environment with relatively diverse aquatic vegetation. Regional vegetation, as reconstructed using the REVEALS model, was spruce woodland mixed with pine, alder and birch, but also included more open environments with hazel, oak, grasslands and sedge‐dominated wetlands. Water shield (Brasenia schreberi), now extinct in Europe, was identified in the Eemian lake deposits, from both pollen and macroscopic remains.
Apparent OSL ages of modern deposits from Fåbergstølsdalen, Norway: implications for sampling glacial sediments
Authors: KING G. E. , ROBINSON R. A. J. , FINCH A. A. 
Published: October 2013

ABSTRACTThe application of optically stimulated luminescence (OSL) dating within glacial settings can be limited where sediments have not had their OSL signal fully reset by sunlight exposure. Heterogeneous bleaching can result in age overestimations, and although it is recognized that certain depositional settings are more likely to have experienced sufficient sunlight exposure to bleach the OSL signal, no comprehensive study has empirically investigated the processes of sediment bleaching, or the variability in bleaching between deposits of the same type and within the same glacial catchment. A suite of modern glacial and glaciofluvial sediments from Fåbergstølsdalen, southern Norway, have been analysed to explore the controls that sedimentary processes and depositional setting have on bleaching of the OSL signal of quartz. There is considerable variability in the residual OSL ages of similar modern deposits, which reflects high sensitivity of the OSL signal to sediment source, sedimentary process, transport distance and depositional setting. Overdispersion values are greatest for the sediments which have been most heterogeneously bleached and these sediments have the lowest residual ages. Sampling strategies that incorporate sufficient consideration of the depositional framework of sample settings can minimize the effects of unbleached residuals on OSL age determinations.
Deeply rooted glaciotectonism in western Denmark: geological composition, structural characteristics and the origin of Varde hill‐island
Authors: HØYER A.‐S. , JØRGENSEN F. , PIOTROWSKI J. A. , JAKOBSEN P. R. 
Published: October 2013

ABSTRACTWe investigate a hill‐island in western Denmark, a major cupola‐hill‐type thrust complex generated by ice‐marginal glaciotectonism. The study uses a unique dataset of densely spaced airborne electromagnetic data, high‐resolution seismic data and borehole information to document the complexity of deeply rooted thrust sheets comprising Miocene to middle Pleistocene deposits. The deformation spans at least 150 m of sediment thickness, placing this complex among the largest glaciotectonic features on record. The main stages of formation of the hill‐island were (1) erosion of Miocene deposits by subglacial tunnel valleys and infill of these valleys in the pre‐Elsterian and Elsterian time, (2) two phases of glaciotectonic thrusting during the Saalian glaciation, (3) erosion by the Saalian ice sheet removing a significant part of the thrust complex and (4) periglacial and postglacial erosion of the hill‐island excavating the glaciotectonic elements. Palaeoglaciological calculations suggest that the Saalian ice sheet that caused the thrusting was thick, had a steep profile, rested on a permafrost wedge and moved slowly, which contrasts with the highly mobile, thin ice lobes of the Last Glaciation.
Moving forward on gait measurement: Toward a more refined approach
Authors: Lord Sue , Galna Brook , Rochester Lynn 
Published: October 2013

ABSTRACTGait is emerging as a powerful measurement tool in neurodegenerative disorders to identify markers of incipient pathology, inform diagnostic algorithms and disease progression, and measure the efficacy of interventions. However, it is unclear which of the many gait outcomes is most appropriate for each of these purposes. In this review, we summarise key topics relating to gait measurement. We draw on literature from Parkinson's disease, ageing, and neurodegenerative disease to address the issue of variable selection with the goal of moving toward a structured approach to measurement. Findings from this review identify a wide range of spatiotemporal and dynamic characteristics; however, their suitability differs according to the aim of measurement. Gait speed is useful as a global characteristic of performance but may not capture the nature of underlying pathology. Inconsistent application, reporting, and interpretation of gait outcomes currently preclude a prescriptive approach. Conceptual models of gait may facilitate a reasoned approach to outcome selection. We also recommend harmonisation of protocols, longitudinal cohort studies, and use of novel technologies and methods of analysis to provide a complete picture of gait. Gait characteristics are “fit for purpose” when selected according to a clear rationale and in accordance with their clinimetric properties. Evidence supports the use of gait as a biomarker of disease and to complement diagnosis and inform disease management. A structured approach to measurement is urgently required to fully realise the contribution gait can make to our understanding of neurodegenerative disease. © 2013 International Parkinson and Movement Disorder Society
Dynamic control of posture across locomotor tasks
Authors: Earhart Gammon M. 
Published: October 2013

ABSTRACTSuccessful locomotion depends on postural control to establish and maintain appropriate postural orientation of body segments relative to one another and to the environment and to ensure dynamic stability of the moving body. This article provides a framework for considering dynamic postural control, highlighting the importance of coordination, consistency, and challenges to postural control posed by various locomotor tasks, such as turning and backward walking. The impacts of aging and various movement disorders on postural control are discussed broadly in an effort to provide a general overview of the field and recommendations for assessment of dynamic postural control across different populations in both clinical and research settings. Suggestions for future research on dynamic postural control during locomotion also are provided and include discussion of opportunities afforded by new and developing technologies, the need for long‐term monitoring of locomotor performance in everyday activities, gaps in our knowledge of how targeted intervention approaches modify dynamic postural control, and the relative paucity of literature regarding dynamic postural control in movement disorder populations other than Parkinson's disease. © 2013 International Parkinson and Movement Disorder Society
Effects of exercise on mobility in people with Parkinson's disease
Authors: van der Kolk Nicolien M. , King Laurie A. 
Published: October 2013

ABSTRACTParkinson's disease is a prevalent neurodegenerative disorder for which only symptomatic treatment exists. Gait and balance disturbance is common in Parkinson's disease and is a major contributor to increased disability and decreased health‐related quality of life and survival. Balance and gait deficits in Parkinson's disease are notoriously difficult to treat and are not significantly helped by pharmacological or surgical treatment. The last two decades have seen a dramatic increase in the research and clinical interest in using exercise as a treatment for mobility problems in people with Parkinson's disease. With exciting advances in basic science research suggesting neurochemical and neuroplastic changes after exercise, an increasing number of high‐quality studies are documenting particular aspects of mobility improving after exercise. Exercise has the potential to help both motor (gait, balance, strength) and nonmotor (depression, apathy, fatigue, constipation) aspects of Parkinson's disease as well as secondary complications of immobility (cardiovascular, osteoporosis). This perspective article focuses primarily on recent evidence on the effects of exercise in improving mobility while highlighting the importance of targeted exercise intervention for maximizing the benefits of exercise. Suggestions for exercise guidelines, adherence issues, and directions for future research are provided. © 2013 International Parkinson and Movement Disorder Society
Higher‐level gait disorders: An open frontier
Authors: Nutt John G. 
Published: October 2013

ABSTRACTThe term higher‐level gait disorders (HLGD) defines a category of balance and gait disorders that are not explained by deficits in strength, tone, sensation, or coordination. HLGD are characterized by various combinations of disequilibrium and impaired locomotion. A plethora of new imaging techniques are beginning to determine the neural circuits that are the basis of these disorders. Although a variety of neurodegenerative and other pathologies can produce HLGD, the most common cause appears to be microvascular disease that causes white‐matter lesions and thereby disrupts balance/locomotor circuits. © 2013 International Parkinson and Movement Disorder Society
Clinical syndromes: Parkinsonian gait
Authors: Ebersbach Georg , Moreau Caroline , Gandor Florin , Defebvre Luc , Devos David 
Published: October 2013

ABSTRACTDisturbances of gait manifest in almost all cases of Parkinson's disease (PD), often leading to loss of mobility and increased mortality. In this review a clinically oriented approach to gait disorders in different stages of PD is presented. In addition, interactions between motor behavior and mental processing will be discussed. Analyzing the clinical features of gait can be helpful to differentiate PD from atypical forms of parkinsonism. Bedside tests to distinguish parkinsonian gait disorders are reviewed. There is still an unmet need to effectively treat complex gait disturbances, which are frequently not responsive to dopamine replacement medication. We thus present current approaches for the management of dopa‐refractory gait disorders. © 2013 International Parkinson and Movement Disorder Society
Deep brain stimulation for gait and postural symptoms in Parkinson's disease
Authors: Pötter‐Nerger Monika , Volkmann Jens 
Published: October 2013

ABSTRACTIn patients with Parkinson's disease, gait and balance difficulties have emerged as some of the main therapeutic concerns. During earlier stages of the disease, the dopamine‐responsive aspects of gait disorder can be treated initially with dopaminergic drugs or deep brain stimulation. However, certain temporal aspects of parkinsonian gait disorder remain therapeutically resistant in both the short term and the long term. In this review, we summarize the effects of deep brain stimulation on gait and postural symptoms in the five currently available targets (subthalamic nucleus, globus pallidus, ventralis intermedius thalamic nucleus, pedunculopontine nucleus, and substantia nigra) and describe programming strategies for patients who are mainly disabled by gait problems. © 2013 International Parkinson and Movement Disorder Society