2,964 research outputs found
A forgotten Roman marble base in the National Museum of Archaeology
A badly damaged Roman marble base now in Valletta, Malta, was first published in 1647 and then in 1787. It has been neglected since, mainly because there have been doubts about whether or not it is a genuine antiquity. This study argues for its authenticity, and contextualizes the relief sculpture that decorates three of its sides. The front carries a depiction of Sicilia, the personification of the Roman province of Sicily to which the Maltese Islands belonged. The image is set in context within the small group of known personifications of Sicilia elsewhere. Identical side panels each show a man with what is interpreted here as a turtle balanced on his knee, an apparently unique depiction of these creatures in Roman sculpture. It is suggested that turtles, now scarce in the Mediterranean, were once plentiful in the waters off both Malta and Sicily. In a secondary period, perhaps in the late eighteenth century, the base was badly mutilated during its conversion for use as a fountain. Whether it ever functioned as such is uncertain.peer-reviewe
Locomotor kinematics of the manus and pes in dinocephalian therapsids reconstructed from three-dimensional morphology of footprints from Gansfontein, South Africa
The Gansfontein paleosurface from the Late PermianAbrahamskraal Formation (Beaufort Group, TapinocephalusAssemblage Zone) near Fraserburg, South Africa, preserves several vertebratetrackways. Among the best-preserved trackways is a series of several footprintsthat have been attributed to a single dinocephalian therapsid walking acrossthe surface. This attribution is based on both the large size of the footprints(25 cm in breadth), and the reduction of digit I in the manus and pes. However,a curious feature of this trackway is that, in contrast to the straight digitsindicated by skeletal specimens of dinocephalians, the digit impressions from theprints are curved so that their tips point medially. To test hypotheses aboutthe locomotor kinematics of the dinocephalian manus and pes that produced thesecurved-digit prints, we constructed contour maps that depicted how the depth ofan impression varied within individual prints. In our initial analysis, we constructedthe maps by pouring milk into the prints in successive increments of 2 mm inheight, and tracing the perimeters of filled areas on translucent paper fixedto the paleosurface by tape. We have also used surface scanners to generatedepth profiles with finer scale resolution. These analyses indicated that thedistal tips of digit impressions are among the shallowest portions of theprints, a pattern consistent with outward rotation of the hand and foot duringstance. In addition, heel impressions are lacking in the prints, indicatingthat the animal that made them may have used digitigrade foot posture. Spacing betweenleft and right prints is small, less than the breadth of individual prints.However, the presence of foot rotation during stance suggests thatdinocephalians used sprawling, rather than parasagittal limb posture. Closespacing of footprints likely resulted from a combination of lateral bending ofthe body and significant cranio-caudal limb excursion, rather than increasedadduction of the limbs under the body.Fil: Blob, Richard W.. Clemson University; Estados UnidosFil: Wilson, Jeffrey A.. University of Michigan; Estados UnidosFil: Marsicano, Claudia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Panko, Laura J.. Northwestern University; Estados UnidosFil: Smith, Roger M.. Iziko South African Museum Cape Town; Sudáfrica77th Annual Meeting of the Society of Vertebrate PaleontologyCanadáSociety of Vertebrate Paleontolog
Molecular expression patterns in the synovium and their association with advanced symptomatic knee osteoarthritis
Objective: Osteoarthritis (OA) is a major source of knee pain. Mechanisms of OA knee pain are incompletely understood but include synovial pathology. We aimed to identify molecular expression patterns in the synovium associated with symptomatic knee OA.Design: Snap frozen synovia were from people undergoing total knee replacement (TKR) for advanced OA, or from post-mortem (PM) cases who had not sought help for knee pain. Associations with OA symptoms were determined using discovery and validation samples, each comprising TKR and post mortem (PM) cases matched for chondropathy (Symptomatic or Asymptomatic Chondropathy). Associations with OA were determined by comparing age matched TKR and PM control cases. Real-time quantitative PCR for 96 genes involved in inflammation and nerve sensitisation used TaqMan® Array Cards in discovery and validation samples, and protein expression for replicated genes was quantified using Luminex bead assay.Results: Eight genes were differentially expressed between asymptomatic and symptomatic chondropathy cases and replicated between discovery and validation samples (P3-fold change). Of these, matrix metalloprotease (MMP)-1 was also increased whereas interleukin-1 receptor 1 (IL1R1) and vascular endothelial growth factor (VEGF) were decreased at the protein level in the synovium of symptomatic compared to asymptomatic chondropathy cases. MMP1 protein expression was also increased in OA compared to PM controls.Conclusion: Associations of symptomatic OA may suggest roles of MMP1 expression and IL1R1 and VEGF pathways in OA pain. Better understanding of which inflammation-associated molecules mediate OA pain should inform refinement of existing therapies and development of new treatments
Complexity of Fetal Movement Detection Using a Single Doppler Ultrasound Transducer
The objective of this paper is to discuss the complexity of fetal movement detection encountered during development and implementation of an automated single Doppler ultrasonic transducer based instrument. The single transducer instrument was intended to better quantify the duration, velocity, and magnitude of fetal movements. A Corometrics Model 116 fetal heart rate monitor was modified, and a fetal movement detection algorithm (Russell Algorithm) was developed to detect fetal movements on one and two (data fusion) transducers. A Hewlett-Packard (HP) M-1350-A fetal monitor and the Russell Algorithm were used to detect and record fetal movements concurrently on sixty patients between the gestation ages of31 to 41 weeks. Using a computer-controlled SVHS PC-VCR, the instrumental detection of fetal movements was time-linked with real-time video ultrasound. This allowed the fetal movements to be scored by expert examiners on a second-per-second basis. A total of 52,478 seconds of fetal movements was scored using this system. Neither system could accurately define the entire duration, velocity, or magnitude of the fetal movements as detected by real-time ultrasound. The complexity of detecting fetal movements using only one transducer has many shortcomings, such as: the amplitude of the returning Doppler signal, the small area of the fetus monitored by a single transducer, the position of the fetus, the type and variety of fetal movements, and material size and shape
Complexity of Fetal Movement Detection Using a Single Doppler Ultrasound Transducer
The objective of this paper is to discuss the complexity of fetal movement detection encountered during development and implementation of an automated single Doppler ultrasonic transducer based instrument. The single transducer instrument was intended to better quantify the duration, velocity, and magnitude of fetal movements. A Corometrics Model 116 fetal heart rate monitor was modified, and a fetal movement detection algorithm (Russell Algorithm) was developed to detect fetal movements on one and two (data fusion) transducers. A Hewlett-Packard (HP) M-1350-A fetal monitor and the Russell Algorithm were used to detect and record fetal movements concurrently on sixty patients between the gestation ages of31 to 41 weeks. Using a computer-controlled SVHS PC-VCR, the instrumental detection of fetal movements was time-linked with real-time video ultrasound. This allowed the fetal movements to be scored by expert examiners on a second-per-second basis. A total of 52,478 seconds of fetal movements was scored using this system. Neither system could accurately define the entire duration, velocity, or magnitude of the fetal movements as detected by real-time ultrasound. The complexity of detecting fetal movements using only one transducer has many shortcomings, such as: the amplitude of the returning Doppler signal, the small area of the fetus monitored by a single transducer, the position of the fetus, the type and variety of fetal movements, and material size and shape
Tailored second line therapy in asthmatic children with the arginine-16 genotype
The arginine-16 beta-2 receptor genotype confers increased susceptibility to exacerbations in asthmatic children taking regular long acting beta-2 agonists. We therefore evaluated using montelukast as an alternative to salmeterol as tailored second line asthma controller therapy in children expressing this susceptible genotype. 62 persistent asthmatic children with the homozygous arginine-16 genotype were randomized to receive salmeterol 50ug bid or montelukast 5/10mg od as add on to inhaled fluticasone for 1 year. School absences (the primary outcome) were reduced with montelukast arm compared to salmeterol: difference in score = 0.40 (95%CI 0.07-0.87) p=0.005. Albuterol use was also reduced with montelukast compared with salmeterol: difference in score = 0.47 (95%CI 0.16-0.79) p<0.0001. Greater improvements occurred in both symptom and quality of life scores with montelukast vs salmeterol, while there was no difference in FEV1. Montelukast may be suitable as tailored second line controller therapy instead of salmeterol in asthmatic children expressing the susceptible arginine-16 genotype - moving towards a personalised medicine approach to management
Coupled-Cluster Approach to Electron Correlations in the Two-Dimensional Hubbard Model
We have studied electron correlations in the doped two-dimensional (2D)
Hubbard model by using the coupled-cluster method (CCM) to investigate whether
or not the method can be applied to correct the independent particle
approximations actually used in ab-initio band calculations. The double
excitation version of the CCM, implemented using the approximate coupled pair
(ACP) method, account for most of the correlation energies of the 2D Hubbard
model in the weak () and the intermediate regions (). The error is always less than 1% there. The ACP approximation gets
less accurate for large () and/or near half-filling.
Further incorporation of electron correlation effects is necessary in this
region. The accuracy does not depend on the system size and the gap between the
lowest unoccupied level and the highest occupied level due to the finite size
effect. Hence, the CCM may be favorably applied to ab-initio band calculations
on metals as well as semiconductors and insulators.Comment: RevTeX3.0, 4 pages, 4 figure
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Adsorption of aspartic acid on Ni{100}: a combined experimental and theoretical study
Understanding the interaction of amino acids with metal surfaces is essential for the rational design of chiral modifiers able to confer enantioselectivity to metal catalysts. We present here an investigation of the adsorption of aspartic acid (Asp) on the Ni{100} surface, using a combination of synchrotron X-Ray Photoelectron Spectroscopy (XPS) and Near-Edge X-ray Absorption Fine Structure (NEXAFS), and Density Functional Theory (DFT) simulations. Based on the combined analysis of the experimental and simulated data, we can identify the dominant mode of adsorption as a pentadentate configuration with three O atoms at the bridge sites of the surfaces, and the remaining oxygen atom and the amino nitrogen are located on atop sites. From temperature-programmed XPS measurements it was found that Asp starts decomposing above 400 K, which is significantly higher than typical decomposition temperatures of smaller organic molecules on Ni surfaces. Our results offer valuable insights for understanding the role of Asp as a chiral modifier of nickel catalyst surfaces for enantioselective hydrogenation reactions
MSH2–MSH6 stimulates DNA polymerase η, suggesting a role for A:T mutations in antibody genes
Activation-induced cytidine deaminase deaminates cytosine to uracil (dU) in DNA, which leads to mutations at C:G basepairs in immunoglobulin genes during somatic hypermutation. The mechanism that generates mutations at A:T basepairs, however, remains unclear. It appears to require the MSH2–MSH6 mismatch repair heterodimer and DNA polymerase (pol) η, as mutations of A:T are decreased in mice and humans lacking these proteins. Here, we demonstrate that these proteins interact physically and functionally. First, we show that MSH2–MSH6 binds to a U:G mismatch but not to other DNA intermediates produced during base excision repair of dUs, including an abasic site and a deoxyribose phosphate group. Second, MSH2 binds to pol η in solution, and endogenous MSH2 associates with the pol in cell extracts. Third, MSH2–MSH6 stimulates the catalytic activity of pol η in vitro. These observations suggest that the interaction between MSH2–MSH6 and DNA pol η stimulates synthesis of mutations at bases located downstream of the initial dU lesion, including A:T pairs
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