Absence Of Loops Research Articles

Золотые касты со вставками из Косики

The article dwells on the finds in the burial of the Sarmatian skeptuchos of the 1st century BC near Kosika on the Lower Volga of the gold settings, decorated using the cloisonné technique and with inlays of emeralds and glass of different colors. Three of them with inlays in the cloisonné technique, which find parallels among jewelry from the Artyukhov Burial-mound and Asia Minor, are probably dating back to the 2nd century BC, and could originally decorate various objects. 18 other settings are characterized by the absence of loops on the rear or holes for stringing, which excludes their use as elements of necklaces or diadems. These settings find analogies among the finds from the tomb in the Burial-mound A in Karalar in Central Anatolia, in which the Galatian king Sinorix, the father of Deiotaros I (ca. 120–41/40 BC) and the grandfather of Deiotaros II the Younger (Philopator), died in the battle under Philippi in 42 BC, was possibly buried. Like by the settings from Karalar, a significant number of settings from Kosika are decorated with green inlays of emerald and beryl, which were widely used in jewelry of the Late Hellenistic and Early Imperial periods. Along with other unique items from the burial on the Lower Volga, gold settings with inlays, most likely used in the interior decoration of the grave or in the decoration of the bone handle of the ceremonial dagger, emphasize the belonging of the burial to the highest rank of the Sarmatian elite.

Clinical Outcomes of the Lund, Toronto, and Organ Care System Protocols for Normothermic Ex Vivo Lung Perfusion: A Systematic Review and Pursuit of Network Meta-Analysis

Purpose Ex Vivo Lung Perfusion (EVLP) is an excellent method to preserve and recondition donor lungs, thus increasing the lung donor pool. This systematic review summarizes studies comparing both primary graft dysfunction (PGD) and survival between EVLP and conventional lung transplantation (c-LTx), or between different EVLP protocols. The objective is to evaluate outcomes of the three main EVLP protocols: ‘Lund’, ‘Toronto’ and ‘Organ Care System’ (OCS), through a network meta-analysis (NMA). Methods A systematic search was performed in Pubmed, Embase, the Cochrane library and Web of Science. Studies performing EVLP on initially discarded donor lungs were independently assessed for eligibility by two researchers. Data on study design, participants, and EVLP methods were extracted, together with outcomes such as survival and PGD. The generated database was assessed on meeting the assumptions for NMA. Results Nine studies were included: two non-randomised clinical trials (n = 240), and four prospective (n = 1360) and three retrospective observational cohort studies (n = 540). The study protocols could be divided into: Toronto (5/9), Lund (3/9) and OCS (1/9). Most frequently reported outcomes were PGD grade 3 at 72 hours post-LTx, and one-month and one-year survival. All included studies compared EVLP to c-LTx, providing solely indirect evidence for comparison between protocols and thus no loops within the NMA model. In the absence of loops, consistency within the model cannot be statistically assessed. Thus, thorough examination for differences that could modify the treatment effect is required. Substantial variations were found in study design, type of LTx, and participant characteristics. It was therefore not feasible to construct a subset of studies that met the similarity and consistency assumptions of NMA. Conclusion Currently, no substantiated statistical comparison can be made between different EVLP protocols. Further attempts at NMA are dependent on the introduction of studies comparing multiple EVLP protocols, or an increase in randomised controlled trials performing EVLP on standard donor lungs. Alternatively, collaborative data management between EVLP centres would be a promising way to explore the effect of different protocols, and their individual components, on patient outcomes.

AB0566 NAILFOLD EXTENT OF REDUCED CAPILLARY DENSITY IS ASSOCIATED WITH DIGITAL ULCERS AND WITH AN INCREASED RISK OF DIGITAL ULCERS IN SYSTEMIC SCLEROSIS

Background:A growing evidence supports the role of microvasculopathy as a primary pathogenic event in systemic sclerosis (SSc). The most commonly used imaging technique to identify microangiopathy in SSc is high magnification videocapillaroscopy (NVC), and reduced capillary density and/or capillary loss, which is a typical feature of “scleroderma microangiopathy”, easily identified by NVC, has been associated with digital ulcers (DUs). Different approaches have been proposed to measure capillary density or capillary loss. Some of these were qualitative methods, others semi-quantitative, others only concerned a limited nailfold area, without ever evaluating the overall density, which is more suitable for quantitative estimate.Objectives:To assess the association between the extent of different values of nailfold capillary density and the presence of DUs and to identify the risk of developing DUs, based on quantitative parameters.Methods:The study involved 54 SSc selected patients (47 women and 7 men, mean age 59.5 years, 50 with limited and 4 with diffuse). The study population came from an ongoing database, that includes clinical and laboratory data of patients with definite SSc. A videocapillaroscope (VideoCap® 3.0, DS Medica, Milan, Italy) with a 200x optical probe was used. During examination, eight fingers (fingers 2–5 of each hand), 4 fields per finger, according to the standard literature were assessed. For each patient, a total of 32 images were collected, then classified as having either “normal”, “non-specific” or the “scleroderma pattern” (SP). Capillary density was defined as the number of capillaries/mm in the distal row, regardless of its shape and morphology. Avascular areas were defined by the absence of loops within a width/area extending over more than 500 microns. For each patient, the SP images were further graded with no/slight reduction of the capillary density (7-9 loops/mm) (NOR), with a well-defined reduction of capillary density (6-4 loops/mm) (RED) and with loss of capillaries (<4) plus avascular areas (AA). Then, the overall percentages were calculated (the number with SP, the number with NOR, with RED and with AA, respect to 32), thus obtaining the quantitative measures. All data were analysed using the MedCalc® version 18.6; 64-bit (MedCalc Software, Mariakerke, Belgium).Results:A total of 1728 images were analyzed. Patients with DUs were 16/54 (29.6%). All patients had a SP, but only five patients showed a SP along the entire nailfold. A comparison between patients with or without DUs showed a significant difference both for the overall extent of AA (p=0.032), and particularly for the overall extent of RED (p<0.001). No significant difference was found regarding the overall extent of the SP (p=0.085). Factor significantly associated with DUs in multivariate analysis was the overall extent of RED (p=0.0286). The ROC curve was very effective at discriminating the capillary feature able to distinguish patients with DUs from patients without DUs. The discriminatory power of the overall extent of RED was very good, with an AUC of 0.948 (95 % CI 0.852 ± 0.990). Then, we calculated the cut-off values of the overall extent of RED for presence/absence of DUs with the highest combination of sensitivity and specificity. The resulting cut-off value (Yourden index of 0.825) was >68.7 (sensitivity 92.31 %; specificity 90.24 %) with a LR+ of 9.46.Conclusion:Our data strongly support that the capillary density between 4 and 6 loops/mm is the best capillaroscopic quantitative measure associated with DUs and able to discriminate the probability of having DUs. If all SSc-specific antibodies and/or other laboratory/clinical parameters are not yet available, the overall capillary density can allow physicians to assess SSc patients easily, regarding DUs and risk for developing DUs.Disclosure of Interests:None declared

A network model for determining decomposition, topology, and properties of the woody crown

The acquisition of resources and airspace of woody crown occur by way of axes supporting annexes. Regardless of age, size, or branching system (monopodial or sympodial), the woody crown shows branched leafy axes implementing an aerial network. We propose here to represent the woody crown through a network comprised of two components, the segments of woody axes named connectors (CO) delimited by nodes (NO) as the branching regions. CO may link NO of different categories (regular, initial, final, and emission) as defined by the relative position of the NO in a crown and how many CO the NO has. The woody crown network (WCN) is similar to a random network with the probability of NO having some CO following an exponential decay. The absence of loops and real hubs weakened the robustness of WCN against failure or attacks on NO. The quantities of NO and CO and the proportions between them were the features of decomposition, and the distances measured in some CO between types of NO captured the topological characteristics of WCN. By combining decomposition and topology, we disclosed some properties of WCN, such as navigability, vulnerability, symmetry, and complexity. Navigability and complexity increased, while vulnerability and symmetry decreased exponentially as the size (ΣNO) of WCN enlarged. The behavior of properties as a function of ΣNO exposed some limits to mitigate the inherent hydraulic resistance during WCN development. Decomposition, topology, and properties of WCN in trees of Cerrado vegetation were interrelated to other crown traits revealing the strategies for acquiring airspace.

THE OVERVIEW OF METHOD OF BALANCED RESOURSE RESERVATION AND MULTICAST ROUTING IN TELECOMMUNICATION NETWORK

The overview of a mathematical model for multicast routing supporting shared explicit reservation of link resource was presented, which is introduced by linear expressions that responsible for ensuring the connectivity of the calculated multicast routes, as well as the absence of loops in them. The novelty of the model consists in introducing conditions for preventing congestion of communication links when implementing a shared explicit reservation, in which a link resource is allocated to several flows simultaneously, but the list of these flows is strictly defined. The task of routing multicast flows supporting shared explicit reservation of link resource is formulated as an optimization problem of mixed integer linear programming. The use of the proposed model makes it possible to exploit the available link resource more efficiently (on average, from 15 to 25%) by ensuring the consistency of solutions for multicast routing tasks and organizing of the shared explicit reservation.

Managing Universities for the Entrepreneurial Society: Entrepreneurial Loops and Innovative Teaching Initiatives

Drawing upon the entrepreneurial spirals concept, this article examines how managerial practices influence entrepreneurial intent in traditional academic activities. The international inquiry analyses innovative teaching into six business schools in France, Canada and Morocco. At the complex interplay between individual goals and organizational objectives, three entrepreneurial loops are identified: converging, diverging and absence of loop. Findings suggest that university management remains a challenge as an appropriate balanced management is required for the changing university’s mission towards social and economic well-being. The conditions of successful academic entrepreneurial activities are outlined across three propositions.

Engineering the Mechanical Properties of Polymer Networks with Precise Doping of Primary Defects.

Polymer networks are extensively utilized across numerous applications ranging from commodity superabsorbent polymers and coatings to high-performance microelectronics and biomaterials. For many applications, desirable properties are known; however, achieving them has been challenging. Additionally, the accurate prediction of elastic modulus has been a long-standing difficulty owing to the presence of loops. By tuning the prepolymer formulation through precise doping of monomers, specific primary network defects can be programmed into an elastomeric scaffold, without alteration of their resulting chemistry. The addition of these monomers that respond mechanically as primary defects is used both to understand their impact on the resulting mechanical properties of the materials and as a method to engineer the mechanical properties. Indeed, these materials exhibit identical bulk and surface chemistry, yet vastly different mechanical properties. Further, we have adapted the real elastic network theory (RENT) to the case of primary defects in the absence of loops, thus providing new insights into the mechanism for material strength and failure in polymer networks arising from primary network defects, and to accurately predict the elastic modulus of the polymer system. The versatility of the approach we describe and the fundamental knowledge gained from this study can lead to new advancements in the development of novel materials with precisely defined and predictable chemical, physical, and mechanical properties.

Structural Mapping and Functional Characterization of Zebrafish Class B G-Protein Coupled Receptor (GPCR) with Dual Ligand Selectivity towards GLP-1 and Glucagon.

GLP-1 and glucagon regulate glucose metabolism through a network of metabolic pathways initiated upon binding to their specific receptors that belong to class B G-protein coupled receptors (GPCRs). The therapeutic potential of glucagon is currently being evaluated, while GLP-1 is already used in the treatment of type 2 diabetes and obesity. Development of a second generation of GLP-1 based therapeutics depends on a molecular and structural understanding of the interactions between the GLP-1 receptor (GLP-1R) and its ligand GLP-1. There is considerable sequence conservation between GLP-1 and glucagon and between the hGLP-1R and human glucagon receptor (hGCGR), yet each receptor recognizes only its own specific ligand. Glucagon receptors in fish and frogs also exhibit ligand selectivity only towards glucagon and not GLP-1. Based on competitive binding experiments and assays of increase in intracellular cAMP, we demonstrate here that a GPCR in zebrafish (Danio rerio) exhibits dual ligand selectivity towards GLP-1 and glucagon, a characteristic not found in mammals. Further, many structural features found in hGLP-1R and hGCGR are also found in this zebrafish GPCR (zfGPCR). We show this by mapping of its sequence and structural features onto the hGLP-1R and hGCGR based on their partial and complementary crystal structures. Thus, we propose that zfGPCR represents a dual GLP-1R/GCGR. The main differences between the three receptors are in their stalk regions that connect their N-terminal extracellular domains (NECDs) with their transmembrane domains and the absence of loop 3 in the NECD in zfGLP-1R/GCGR. These observations suggest that the interactions between GLP-1 and glucagon with loop 3 and the stalk regions may induce different conformational changes in hGLP-1R and hGCGR upon ligand binding and activation that lead to selective recognition of their native ligands.

FRI0498 A Quantitative Videocapillaroscopic Study about the Relationship of Avascular Areas with the Clinical Characteristics and Disease Severity in Patients with Systemic Sclerosis

BackgroundSeveral studies have been carried out in systemic sclerosis (SSc) in order to correlate the microvascular damage with the clinical features and/or organ involvement, most of them by using the...

Nicking Single DNA Molecules to Study Initiation of Mismatch Repair

In E. coli the error rate of replication (10-6) is lowered another thousand-fold by the MutS, MutL and MutH system of proteins responsible for directing repair of base insertions, deletions, and mismatches. We provide here a study using magnetic trapping of single DNA molecules to analyze the interactions between these proteins and DNA containing a single indel mutation. MutS, albeit at relatively high concentrations, can be observed to stabilize small thermal loops of DNA on an indel-containing substrate, and this in an ATP-dependent manner; addition of MutL reduces the concentration of MutS required for looping to be observed. Loop size distributes roughly according to a J-factor distribution, and decreases as force increases, consistent with thermal loop stabilization by MutSL complexes. The reaction is allowed to proceed to the stage of DNA incision by the addition of MutH. With the further addition of T4 DNA ligase the steady-state rate of incision can be studied as a function of different parameters including DNA supercoiling, extending force, length of substrate DNA, or relative positioning between indel and incision sites. We compare these results to biophysical models for the protein-DNA interactions involved as well as stochastic simulations of the incision reaction occurring on linear DNA with a centrally-located indel and two symmetric proximal incision sites. Experimental results indicate that DNA incision can occur even in the absence of looping, and comparison to simulations supports the view that communication from DNA mismatch to DNA incision site takes place via thermal diffusion.

Watching Genes Loop the Loop

Watching Genes Loop the Loop

Variation in Male and Female Genitalia Among Ten Species of North AmericanAnthocoris(Hemiptera: Heteroptera: Anthocoridae)

AbstractWe compared morphology of internal reproductive anatomy and genitalia among 10 species of North American Anthocoris (Hemiptera: Heteroptera: Anthocoridae). Reproductive structures of males, including internal reproductive organs (testes, seminal vesicles, ejaculatory bulb, phallus), the paramere, and the endosoma, were found to vary in size, shape, and appearance among the 10 species, although with similarities among species within some groupings. All species except Anthocoris bakeri Poppius have two testicular follicles per testis; A. bakeri has five to seven follicles per testis. In seven of the 10 species, a longitudinal groove was found to be present on the paramere; we believe this groove functions to guide the male's intromittent organ as it enters the female during copulation. Variation among species in morphology of the male's inflated endosoma included differences in length, presence or absence of looping, and in presence of spinulate, dentate, or tuberculate projections. The summary presented here is the first description of the endosoma for any species of Anthocoris. We observed substantial variation among species in length of the female's copulatory tube (i.e., the organ which receives the male's intromittent organ), although again with some similarities among certain groupings of species. Variation in length of the female's copulatory tube parallels variation in length of the male's endosoma, which suggests that morphology of genitalia within this genus has coevolved between sexes.

Random walks on complex trees

We study the properties of random walks on complex trees. We observe that the absence of loops is reflected in physical observables showing large differences with respect to their looped counterparts. First, both the vertex discovery rate and the mean topological displacement from the origin present a considerable slowing down in the tree case. Second, the mean first passage time (MFPT) displays a logarithmic degree dependence, in contrast to the inverse degree shape exhibited in looped networks. This deviation can be ascribed to the dominance of source-target topological distance in trees. To show this, we study the distance dependence of a symmetrized MFPT and derive its logarithmic profile, obtaining good agreement with simulation results. These unique properties shed light on the recently reported anomalies observed in diffusive dynamical systems on trees.

Cooperation in the noisy case: Prisoner’s dilemma game on two types of regular random graphs

We have studied an evolutionary prisoner's dilemma game with players located on two types of random regular graphs with a degree of 4. The analysis is focused on the effects of payoffs and noise (temperature) on the maintenance of cooperation. When varying the noise level and/or the highest payoff, the system exhibits a second-order phase transition from a mixed state of cooperators and defectors to an absorbing state where only defectors remain alive. For the random regular graph (and Bethe lattice) the behavior of the system is similar to those found previously on the square lattice with nearest neighbor interactions, although the measure of cooperation is enhanced by the absence of loops in the connectivity structure. For low noise the optimal connectivity structure is built up from randomly connected triangles.

Hopping on the Bethe lattice: Exact results for densities of states and dynamical mean-field theory

We derive an operator identity which relates tight-binding Hamiltonians with arbitrary hopping on the Bethe lattice to the Hamiltonian with nearest-neighbor hopping. This provides an exact expression for the density of states (DOS) of a non-interacting quantum-mechanical particle for any hopping. We present analytic results for the DOS corresponding to hopping between nearest and next-nearest neighbors, and also for exponentially decreasing hopping amplitudes. Conversely it is possible to construct a hopping Hamiltonian on the Bethe lattice for any given DOS. These methods are based only on the so-called distance regularity of the infinite Bethe lattice, and not on the absence of loops. Results are also obtained for the triangular Husimi cactus, a recursive lattice with loops. Furthermore we derive the exact self-consistency equations arising in the context of dynamical mean-field theory, which serve as a starting point for studies of Hubbard-type models with frustration.

IMPROVED RESULTS ON POISSON PROCESS APPROXIMATION IN JACKSON NETWORKS

Melamed (1979) proved that for an open migration process, a necessary and sufficient condition for the equilibrium flow along a link to be Poissonian is the absence of loops: no customer can travel along the link more than once. Barbour and Brown (1996) quantified the statement by allowing the customers a small probability of travelling along the link more than once and proved Poisson process approximation theorems analogous to Melamed's Theorem. Amongst the three bounds presented in Barbour and Brown (1996), the one in terms of the Wasserstein metric is of particular interest since it reveals more insightful information about the closeness between the process of flows and an approximating Poisson process, and it is small when the parameter of the system is small, except a logarithmic factor in terms of time in which the flows are considered. The bound was later improved by Brown, Weinberg and Xia (2000) who showed that the logarithmic factor in terms of time can be lifted at the cost of an extra parameter being introduced into the bound. In this paper, we present a new bound which simplifies and sharpens the bounds in the above-mentioned two papers and compare the performance of these bounds for a simple open migration process.

Addition of Missing Loops and Domains to Protein Models by X-Ray Solution Scattering

Inherent flexibility and conformational heterogeneity in proteins can often result in the absence of loops and even entire domains in structures determined by x-ray crystallographic or NMR methods. X-ray solution scattering offers the possibility of obtaining complementary information regarding the structures of these disordered protein regions. Methods are presented for adding missing loops or domains by fixing a known structure and building the unknown regions to fit the experimental scattering data obtained from the entire particle. Simulated annealing was used to minimize a scoring function containing the discrepancy between the experimental and calculated patterns and the relevant penalty terms. In low-resolution models where interface location between known and unknown parts is not available, a gas of dummy residues represents the missing domain. In high-resolution models where the interface is known, loops or domains are represented as interconnected chains (or ensembles of residues with spring forces between the C α atoms), attached to known position(s) in the available structure. Native-like folds of missing fragments can be obtained by imposing residue-specific constraints. After validation in simulated examples, the methods have been applied to add missing loops or domains to several proteins where partial structures were available.

Electrical and thermal behavior of non-ferrous noble metal electrodes exposed to MRI fields

MRI is a valuable tool in invasive epilepsy surgery evaluation. However, its use is limited due to concerns that under those conditions it may injure the brain. This study investigates the thermal and electrical behavior of electrodes exposed to MRI fields, using a phantom brain implanted with depth and grid electrodes.Voltages and temperatures were measured during various MRI scan sequences at electrodes whose numbers and orientations were varied in a pre-specified manner. Maximum SAR recorded during the scans was 1.5 W/kg. Temperature changes and DC voltages were negligible. Peak-to-peak voltage induction depended on the position, number of electrodes, MRI modality and sequence. Voltages exceeded 40 V at 63.6 MHz, only when electrode wires formed loops, reaching peak values of 72 V at RF. Estimated charge densities due to leakage currents were well within the safety limit for neural tissue, which is 30 μC/cm2, even at the highest voltages.Although in the absence of loops, voltages and charge densities recorded in this study were, under most conditions within safe limits for brain tissue, their dependence on: a) the physical dimensions of electrode arrays; b) their position/orientation in reference to each other and to the plane of the magnetic field, and c) the MR sequence and slice thickness, may make these observations and conclusions not generalizable and thus not directly applicable to other conditions with regard to safety risks assessment.

Topology of the fittest transportation network.

The presence or absence of loops in the emergent transportation networks, that are characterized by a minimum overall cost, is shown to depend on the convexity of the cost function for the local transportation of material. Our results are directly applicable to a variety of situations across disciplines.

Protein-RNA interactions in the U5 snRNP of Saccharomyces cerevisiae.

We present here the first insights into the organization of proteins on the RNA in the U5 snRNP of Saccharomyces cerevisiae. Photo-crosslinking with uniformly labeled U5 RNA in snRNPs reconstituted in vitro revealed five contacting proteins, Prp8p, Snu114p, p30, p16, and p10, contact by the three smaller proteins requiring an intact Sm site. Site-specific crosslinking showed that Snu114p contacts the 5' side of internal loop 1, whereas Prp8p interacts with five different regions of the 5' stem-loop, but not with the Sm site or 3' stem-loop. Both internal loops in the 5' domain are essential for Prp8p to associate with the snRNP, but the conserved loop 1 is not, although this is the region to which Prp8p crosslinks most strongly. The extensive contacts between Prp8p and the 5' stem-loop of U5 RNA support the hypothesis that, in spliceosomes, Prp8p stabilizes loop 1-exon interactions. Moreover, data showing that Prp8p contacts the exons even in the absence of loop 1 indicate that Prp8p may be the principal anchoring factor for exons in the spliceosome. This and the close proximity of the spliceosomal translocase, Snu114p, to U5 loop 1 and Prp8p support and extend the proposal that Snu114p mimics U5 loop 1 during a translocation event in the spliceosome.