1,730 research outputs found
Monocationic μ-diborolyl triple-decker complexes [CpCo(μ-1,3-C 3B2Me5)M(ring)]+: Synthesis, structures, and electrochemistry
No full textCationic triple-decker complexes with a bridging diborolyl ligand, [CpCo(μ-1,3-C3B2Me5)M(ring)]+ (M(ring) = CoCp (2a), CoCp* (2b), RhCp (3a), RhCp* (3b), IrCp (4a), IrCp* (4b), Ru(C6H6) (5a), Ru(p-MeC 6H4Pri) (5b), Ru(C6Me6) (5c), Ru(η6-cycloheptatriene) (6)), were synthesized by reaction of CpCo(μ-1,3-C3B2Me5)Tl with [M(ring)Hal2]2. The structures of 2aBPh4, 2bPF6, 4aPF6, 5aOTf, and 5cPF6 were determined by X-ray diffraction. The electron-transfer ability of the complexes has been ascertained by electrochemical and spectroelectrochemical techniques. In general, they are able to shuttle reversibly in the sequence 2+/+/0/-, plausibly affording completely delocalized mixed-valence derivatives. DFT calculations revealed structural changes accompanying redox processes and satisfactorily predicted the potentials for the first reduction and first oxidation. © 2013 American Chemical Society
Gap junctions, dendrites and resonances : a recipe for tuning network dynamics
No full textGap junctions, also referred to as electrical synapses, are expressed along the entire central nervous system and are important in mediating various brain rhythms in both normal and pathological states. These connections can form between the dendritic trees of individual cells. Many dendrites express membrane channels that confer on them a form of sub-threshold resonant dynamics. To obtain insight into the modulatory role of gap junctions in tuning networks of resonant dendritic trees, we generalise the “sum-over-trips” formalism for calculating the response function of a single branching dendrite to a gap junctionally coupled network. Each cell in the network is modelled by a soma connected to an arbitrary structure of dendrites with resonant membrane. The network is treated as a single extended tree structure with dendro-dendritic gap junction coupling. We present the generalised “sum-over-trips” rules for constructing the network response function in terms of a set of coefficients defined at special branching, somatic and gap-junctional nodes. Applying this framework to a two-cell network, we construct compact closed form solutions for the network response function in the Laplace (frequency) domain and study how a preferred frequency in each soma depends on the location and strength of the gap junction
Computational convergence of the path integral for real dendritic morphologies
No full textNeurons are characterised by a morphological structure unique amongst biological cells, the core of which is the dendritic tree. The vast number of dendritic geometries, combined with heterogeneous properties of the cell membrane, continue to challenge scientists in predicting neuronal input-output relationships, even in the case of sub-threshold dendritic currents. The Green’s function obtained for a given dendritic geometry provides this functional relationship for passive or quasi-active dendrites and can be constructed by a sum-over-trips approach based on a path integral formalism. In this paper, we introduce a number of efficient algorithms for realisation of the sum-over-trips framework and investigate the convergence of these algorithms on different dendritic geometries. We demonstrate that the convergence of the trip sampling methods strongly depends on dendritic morphology as well as the biophysical properties of the cell membrane. For real morphologies, the number of trips to guarantee a small convergence error might become very large and strongly affect computational efficiency. As an alternative, we introduce a highly-efficient matrix method which can be applied to arbitrary branching structures
Stichotvorenie V. Krivulina‚ Čto rifmovalos'; (1990), refleksija krizisa neoficial'noj kul'tury.
No full textNel olume dedicato all'emblematico anno 1990 in Urss e ai prodromi culturali della Russia post-sovietica, si inserisce uno studio analitico di un testo di Viktor Krivulin, poeta e grande promotore della cultura non conformista sin dagli anni Settanta, che descrive la fine di una esperienza culturale indipendente nata dal rapporto dialettico e con quella ufficiale sovietica
Switching off: disruptive TMS reveals distinct contributions of the posterior middle temporal gyrus and angular gyrus to bilingual speech production
No full textThe role of the left temporoparietal cortex in speech production has been extensively studied during native language processing, proving crucial in controlled lexico-semantic retrieval under varying cognitive demands. Yet, its role in bilinguals, f luent in both native and second languages, remains poorly understood. Here, we employed continuous theta burst stimulation to disrupt neural activity in the left posterior middle-temporal gyrus (pMTG) and angular gyrus (AG) while Italian–Friulian bilinguals performed a cued picture-naming task. The task involved between-language (naming objects in Italian or Friulian) and within-language blocks (naming objects [“knife”] or associated actions [“cut”] in a single language) in which participants could either maintain (non-switch) or change (switch) instructions based on cues. During within-language blocks, cTBS over the pMTG entailed faster naming for high-demanding switch trials, while cTBS to the AG elicited slower latencies in low-demanding non-switch trials. No cTBS effects were observed in the between-language block. Our findings suggest a causal involvement of the left pMTG and AG in lexico-semantic processing across languages, with distinct contributions to controlled vs. “automatic” retrieval, respectively. However, they do not support the existence of shared control mechanisms within and between language(s) production. Altogether, these results inform neurobiological models of semantic control in bilinguals
Reduced intensity conditioning regimen followed by glycosylated G-CSF mobilized PBSCT in patients with solid tumors and malignant lymphomas
No full textThe aim of this pilot study was to exploit the graft-versus-tumor potential of allogeneic transplants while improving safety of the procedure. Twelve patients with advanced hematological malignancies and solid tumors underwent a low intensity conditioning regimen (fludarabine and cyclophosphamide) followed by an allogeneic peripheral blood stem cell transplantation. The median time to achieve an absolute neutrophil count of more than 0.5 x 10(9)/l and an untransfused platelet count of more than 20 x 10(9)/l was 15 and 14 days, respectively. The main extra-hematological toxicities were mucositis and infections. Acute graft-versus-host (GVHD) disease was experienced by 62% of evaluable patients (grade II/B or III/C 80%) responsive to steroids. Extensive chronic GVHD was observed in 62% of patients. Non-relapse transplant-related mortality by day +30 was observed in three patients (25%). Eight out of 12 patients were full donor chimeric by day +100. One patient showed a mixed chimerism at day +37 when he died from progressive disease. One patient was in complete remission (CR) before allogeneic transplantation, and after transplantation four patients achieved CR and four experienced progressive disease. Our study confirms that a low intensity conditioning regimen for allogeneic stem cell transplantation is feasible and effective in heavily pretreated patients
Modeling of InAs-InSb nanowires grown by Au-assisted chemical beam epitaxy
No full textInteresting phenomena during the Au-assisted chemical beam epitaxy of InAs-InSb nanowire heterostructures have been observed and interpreted within the framework of a theoretical model. An unusual, non-monotonous diameter dependence of the InSb nanowire growth rate is demonstrated experimentally within a range of deposition conditions. Such a behavior is explained by competition between the Gibbs-Thomson effect and different diffusion-induced material fluxes. Theoretical fits to the experimental data obtained at different flux pressures of In and Sb precursors allow us to deduce some important kinetic coefficients. Furthermore, we discuss why the InAs nanowire stem forms in the wurtzite phase while the upper InSb part has a pure zinc blende crystal structure. It is hypothesized that the 30 degrees angular rotation of nanowire when passing from InAs to the InSb part is driven by the lowest surface energy of (1(1) over bar 00) wurtzite and (110) zinc blende facets.ICM
Editorial for special issue on neurodynamics
No full text“Neurodynamics” is an interdisciplinary area of mathematics where dynamical systems theory (deterministic and stochastic) is the primary tool for elucidating the fundamental mechanisms responsible for the behaviour of neural systems (whether biological or synthetic). A meeting on this topic was held at the International Centre for Mathematical Sciences in Edinburgh from March 5–7 in 2012. In this special issue, we have invited seven of the main contributors to this event to expand on their presentations and highlight the use of mathematics in understanding the dynamics of neural systems
Development of Movement Skills in Children with the Down Syndrome on Classes in Adaptive Physical Training
No full textAnnually in Ekaterinburg and the Sverdlovsk region, 40–50 children are born each year with this genetic anomaly. The problem of development and correction of motor disorders in children with Down’s syndrome remains topical. The developed method of adaptive physical education, based on the game method of TEACCH, will help children with Down syndrome improve motor skills, emotional and volitional sphere, which in the future will contribute to successful socialization in society.Ежегодно в Екатеринбурге и Свердловской области рождаются 40–50 детей с синдромом Дауна. Актуальной остается проблема развития и коррекции нарушений двигательной сферы детей с данной генетической мутацией. Разработанная методика адаптивного физического воспитания, основанная на игровом методе TEACCH, поможет детям с синдромом Дауна улучшить двигательные навыки и эмоционально-волевую сферу, что в будущем будет способствовать их успешной социализации
A revision of the Calicotylinae Monticelli, 1903 (Monogenea: Monocotylidae)
No full textA total of 153 elasmobranchs (46 species), either freshly collected from the Gulf of Mexico, USA and Tasmania, Australia or museum specimens collected from various localities worldwide, were examined for calicotyline (Monocotylidae) monogeneans. Thirty-five elasmobranchs, representing 17 species, were infected with Calicotyle spp. which we identified as the following previously described species: C. asterii (Szidat, 1970) Timofeeva, 1985, C. kroyeri Diesing, 1850, C. macrocotyle Cordero, 1944, C. similis (Szidat, 1972) Timofeeva, 1985, C. splendens (Szidat, 1970) Timofeeva, 1985, C. stossichi Braun, 1899 and C urolophi Chisholm, Beverley-Burton and Last, 1991. The Calicotylinae, which comprises the genera Calicotyle and Dictyocotyle, is revised based on supplementary material as well as deposited type-material. We consider 14 of the 17 nominal Calicotyle spp. to be valid. C. rosinae Kusnetzova, 1970 is synonymised with C. macrocotyle, C. sjegi Kusnetzova, 1970 is considered a species inquirenda and C. inermis Woolcock, 1936 a species incertae sedis. Additional data and illustrations to show the morphological features of the hamuli and male copulatory organ, the form of the intestinal caeca, vaginae and ovary and the distribution of the vitellarium are provided for all valid species. The distribution of the 14 hooklets in the adult haptor of Dictyocotyle coeliaca Nybelin, 1941 is illustrated for the first time. We provide new host and locality records for C. asterii, C. kroyeri, C. macrocotyle and C. stossichi and new locality records for C. similis and C. splendens. A key to species of the Calicotylinae is also included. Host-specificity, geographical distribution and the need for information regarding the development of individuals from juvenile to adult are discussed
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