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Search Results: 1 - 10 of 327633 matches for " Russell S. Minns "
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Probing the structure and dynamics of molecular clusters using rotational wavepackets
Gediminas Galinis,Cephise Cacho,Richard T. Chapman,Andrew M. Ellis,Marius Lewerenz,Luis G. Mendoza Luna,Russell S. Minns,Mirjana Mladenovic,Arnaud Rouzée,Emma Springate,I. C. Edmond Turcu,Mark J. Watkins,Klaus von Haeften
Physics , 2014, DOI: 10.1103/PhysRevLett.113.043004
Abstract: The chemical and physical properties of molecular clusters can heavily depend on their size, which makes them very attractive for the design of new materials with tailored properties. Deriving the structure and dynamics of clusters is therefore of major interest in science. Weakly bound clusters can be studied using conventional spectroscopic techniques, but the number of lines observed is often too small for a comprehensive structural analysis. Impulsive alignment generates rotational wavepackets, which provides simultaneous information on structure and dynamics, as has been demonstrated successfully for isolated molecules. Here, we apply this technique for the firsttime to clusters comprising of a molecule and a single helium atom. By forcing the population of high rotational levels in intense laser fields we demonstrate the generation of rich rotational line spectra for this system, establishing the highly delocalised structure and the coherence of rotational wavepacket propagation. Our findings enable studies of clusters of different sizes and complexity as well as incipient superfluidity effects using wavepacket methods.
Carpal tunnel syndrome and the "double crush" hypothesis: a review and implications for chiropractic
Brent S Russell
Chiropractic & Manual Therapies , 2008, DOI: 10.1186/1746-1340-16-2
Abstract: Upton and McComas [1] formalized the hypothesis of the "double crush" syndrome (DCS). They suggested that compression of an axon at one location makes it more sensitive to effects of compression in another location, because of impaired axoplasmic flow. Hypothetically, two lesions with little or no independent clinical ramifications, when combined, lead to appearance or magnification of symptoms [2]. Two areas of compression affecting the same axons do not, alone, meet the criteria of the hypothesis. By definition, a first lesion must render axons more susceptible to effects of a second, leading to more than just the combined, independent effects of two lesions [2]. Upton and McComas [1] used the double crush hypothesis to explain why patients with carpal tunnel syndrome (CTS) sometimes feel pain in the forearm, elbow, upper arm, shoulder, chest, and upper back. They also used it to explain failed attempts at surgical repairs when neither surgery nor CTS diagnosis appeared faulty. They claimed that most patients with CTS not only have compressive lesions at the wrist, but also show evidence of damage to cervical nerve roots.The double crush concept has gained some popularity among chiropractors because it seems to provide a rationale for adjusting the cervical spine when treating CTS. An example of this emphasis on spinal care, implicitly grounded in the double crush hypothesis, can be found on the Web: "90% of all carpal tunnel patients are misdiagnosed. Only 10% of all carpal tunnel patients have the problem in their wrists. Most often the problem exists in the cervical spine with compression or irritation of the nerve root." [3]. Although the chiropractor making this claim may believe it, nothing in the scientific literature supports it. Other doctors of chiropractic accept that median nerve compression commonly occurs in the carpal tunnel but believe that neck problems also contribute to the syndrome. Although it seems that many of my chiropractic colleagues and
The Identification of Protein Kinase C Iota as a Regulator of the Mammalian Heat Shock Response Using Functional Genomic Screens
Frank Boellmann,Russell S. Thomas
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011850
Abstract: The heat shock response is widely used as a surrogate of the general protein quality control system within the cell. This system plays a significant role in aging and many protein folding diseases as well as the responses to other physical and chemical stressors.
On the use of resampling tests for evaluating statistical significance of binding-site co-occurrence
David S Huen, Steven Russell
BMC Bioinformatics , 2010, DOI: 10.1186/1471-2105-11-359
Abstract: We have investigated two resampling approaches for evaluating the statistical significance of binding-site co-occurrence. The permutation test approach was found to yield overly favourable p-values while the independent resampling approach had the opposite effect and is of little use in practical terms. We have developed a new, pragmatically-devised hybrid approach that, when applied to the experimental results of an Polycomb/Trithorax study, yielded p-values consistent with the findings of that study. We extended our investigations to the FL method developed by Haiminen et al, which derives its null distribution from all binding sites within a dataset, and show that the p-value computed for a pair of factors by this method can depend on which other factors are included in that dataset. Both our hybrid method and the FL method appeared to yield plausible estimates of the statistical significance of co-occurrences although our hybrid method was more conservative when applied to the Polycomb/Trithorax dataset.A high-performance parallelized implementation of the hybrid method is available.We propose a new resampling-based co-occurrence significance test and demonstrate that it performs as well as or better than existing methods on a large experimentally-derived dataset. We believe it can be usefully applied to data from high-throughput genome-wide techniques such as ChIP-chip or DamID. The Cooccur package, which implements our approach, accompanies this paper.A large number of proteins are known to bind DNA in a location-specific manner. These include transcription factors, replication factors and chromatin components. It is widely accepted that individual proteins do not usually act in isolation but form multi-protein effector complexes on DNA. When the binding sites of the individual proteins within a complex are determined by genome-wide high-throughput assays, these complexes are revealed as regions where the binding sites of multiple proteins are clustered. When
Provably Bounded-Optimal Agents
S. J. Russell,D. Subramanian
Computer Science , 1995,
Abstract: Since its inception, artificial intelligence has relied upon a theoretical foundation centered around perfect rationality as the desired property of intelligent systems. We argue, as others have done, that this foundation is inadequate because it imposes fundamentally unsatisfiable requirements. As a result, there has arisen a wide gap between theory and practice in AI, hindering progress in the field. We propose instead a property called bounded optimality. Roughly speaking, an agent is bounded-optimal if its program is a solution to the constrained optimization problem presented by its architecture and the task environment. We show how to construct agents with this property for a simple class of machine architectures in a broad class of real-time environments. We illustrate these results using a simple model of an automated mail sorting facility. We also define a weaker property, asymptotic bounded optimality (ABO), that generalizes the notion of optimality in classical complexity theory. We then construct universal ABO programs, i.e., programs that are ABO no matter what real-time constraints are applied. Universal ABO programs can be used as building blocks for more complex systems. We conclude with a discussion of the prospects for bounded optimality as a theoretical basis for AI, and relate it to similar trends in philosophy, economics, and game theory.
Corneal Epithelium Expresses a Variant of P2X7 Receptor in Health and Disease
Courtney Mankus, Celeste Rich, Martin Minns, Vickery Trinkaus-Randall
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028541
Abstract: Improper wound repair of the corneal epithelium can alter refraction of light resulting in impaired vision. We have shown that ATP is released after injury, activates purinergic receptor signaling pathways and plays a major role in wound closure. In many cells or tissues, ATP activates P2X7 receptors leading to cation fluxes and cytotoxicity. The corneal epithelium is an excellent model to study the expression of both the full-length P2X7 form (defined as the canonical receptor) and its truncated forms. When Ca2+ mobilization is induced by BzATP, a P2X7 agonist, it is attenuated in the presence of extracellular Mg2+ or Zn2+, negligible in the absence of extracellular Ca2+, and inhibited by the competitive P2X7 receptor inhibitor, A438079. BzATP enhanced phosphorylation of ERK. Together these responses indicate the presence of a canonical or full-length P2X7 receptor. In addition BzATP enhanced epithelial cell migration, and transfection with siRNA to the P2X7 receptor reduced cell migration. Furthermore, sustained activation did not induce dye uptake indicating the presence of truncated or variant forms that lack the ability to form large pores. Reverse transcription-polymerase chain reaction and Northern blot analysis revealed a P2X7 splice variant. Western blots identified a full-length and truncated form, and the expression pattern changed as cultures progressed from monolayer to stratified. Cross-linking gels demonstrated the presence of homo- and heterotrimers. We examined epithelium from age matched diabetic and non-diabetic corneas patients and detected a 4-fold increase in P2X7 mRNA from diabetic corneal epithelium compared to non-diabetic controls and an increased trend in expression of P2X7variant mRNA. Taken together, these data indicate that corneal epithelial cells express full-length and truncated forms of P2X7, which ultimately allows P2X7 to function as a multifaceted receptor that can mediate cell proliferation and migration or cell death.
The application of data mining techniques for the regionalisation of hydrological variables
M. J. Hall,A. W. Minns,A. K. M. Ashrafuzzaman
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2002,
Abstract: Flood quantile estimation for ungauged catchment areas continues to be a routine problem faced by the practising Engineering Hydrologist, yet the hydrometric networks in many countries are reducing rather than expanding. The result is an increasing reliance on methods for regionalising hydrological variables. Among the most widely applied techniques is the Method of Residuals, an iterative method of classifying catchment areas by their geographical proximity based upon the application of Multiple Linear Regression Analysis (MLRA). Alternative classification techniques, such as cluster analysis, have also been applied but not on a routine basis. However, hydrological regionalisation can also be regarded as a problem in data mining — a search for useful knowledge and models embedded within large data sets. In particular, Artificial Neural Networks (ANNs) can be applied both to classify catchments according to their geomorphological and climatic characteristics and to relate flow quantiles to those characteristics. This approach has been applied to three data sets from the south-west of England and Wales; to England, Wales and Scotland (EWS); and to the islands of Java and Sumatra in Indonesia. The results demonstrated that hydrologically plausible clusters can be obtained under contrasting conditions of climate. The four classes of catchment found in the EWS data set were found to be compatible with the three classes identified in the earlier study of a smaller data set from south-west England and Wales. Relationships for the parameters of the at-site distribution of annual floods can be developed that are superior to those based upon MLRA in terms of root mean square errors of validation data sets. Indeed, the results from Java and Sumatra demonstrate a clear advantage in reduced root mean square error of the dependent flow variable through recognising the presence of three classes of catchment. Wider evaluation of this methodology is recommended. Keywords: regionalisation, floods, catchment characteristics, data mining, artificial neural networks
The Equation of the Universe (According to the Theory of Relation)  [PDF]
Russell Bagdoo
Journal of Modern Physics (JMP) , 2019, DOI: 10.4236/jmp.2019.103022
Abstract: A new equation is found in which the concept of matter-space-time is mathematically connected; gravitation and electromagnetism are also bound by space-time. A mechanism is described showing how velocity, time, distance, matter, and energy are correlated. We are led to ascertain that gravity and electricity are two distinct manifestations of a single underlying process: electro-gravitation. The force of gravitation arises of electromagnetism—inherently much stronger—divided by the cosmological space-time. The radius of space-time belongs to the family of electromagnetic waves: the wavelength is the radius (1026 m) of the universe and the period (1017 s) is its cosmological age. For the first time, the cosmological time, considered as a real physical object, is integrated into a “cosmological equation” which makes coherent what we know regarding the time (its origin, its flow …), the matter, and space. It sets up a mathematical model allowing us to interpret dark energy (or cosmological constant) as being both “negative” and “tired” energy. After an introduction with a brief history of unifications and the presentation of two roughly equal ratios arising out from Dirac’s large-number hypotheses which relate to the ratio of electric force to gravitational force and the ratio of the age of the universe to the atomic time unit associated with atomic processes, we present in §2 this new equation of quantum cosmology which operates the reconciliation between the macrocosm and the microcosm. In §3 and §4, we discuss the irreversible cosmological time resulting from the equation, as well as the role of the mass (heavy) relative to the gravitational constant G. In §5 we discuss the links that the equation establishes between gravitation (structure of condensation) and electromagnetism (structure of expansion), between relativity and quantum theory. We apply the formula to Planck’s time. We speak of the new essential variable? ?\"\", and briefly of a new principle, the principle of compensation. In §6 we discuss the negative energy solutions banned by physics, and we deplore that half of the universe escapes us. We present the electro-gravitation in §7, from the equation which represents a super hydrogen atom. In § 8 we show that the global mass (gravitational) is variable: it increases during the expansion while the mass of the elementary
Scenario for the Origin of Matter (According to the Theory of Relation)  [PDF]
Russell Bagdoo
Journal of Modern Physics (JMP) , 2019, DOI: 10.4236/jmp.2019.102013
Abstract: Where did matter in the universe come from? Where does the mass of matter come from? Particle physicists have used the knowledge acquired in matter and space to imagine a standard scenario to provide satisfactory answers to these major questions. The dominant thought to explain the absence of antimatter in nature is that we had an initially symmetrical universe made of matter and antimatter and that a dissymmetry would have sufficed for more matter having constituted our world than antimatter. This dissymmetry would arise from an anomaly in the number of neutrinos resulting from nuclear reactions which suggest the existence of a new type of titanic neutrino who would exceed the possibilities of the standard model and would justify the absence of antimatter in the macrocosm. We believe that another scenario could better explain why we observe only matter. It involves the validation of the negative energy solution of the Dirac equation, itself derived from the Einstein energy equation. The theory of Relation describes a negative energy ocean with the creation of real particle/antiparticle pairs. The origin of the masses of the particles would come from this ocean. A physical mechanism would allow their separation in the opposite direction and, therefore, the matter would be enriched at the expense of the ocean. The matter would be favored without resorting to negation or annihilation of negative energy, without the need for a CP (the behavioral difference between particle and antiparticle) violation that would be responsible for matter/antimatter asymmetry in the universe. And without the savior contribution of an undetectable obese neutrino: his search appears to us more a desperate act towards an “ultra-massive catastrophe” than a real effort to try to discover what really happened.
The Use of Epidermal Growth Factor Receptor Monoclonal Antibodies in Squamous Cell Carcinoma of the Head and Neck
Jeffery S. Russell,A. Dimitrios Colevas
Chemotherapy Research and Practice , 2012, DOI: 10.1155/2012/761518
Abstract: Targeting of the EGF receptor (EGFR) has become a standard of care in several tumor types. In squamous cell carcinoma of the head and neck, monoclonal antibodies directed against EGFR have become a regular component of therapy for curative as well as palliative treatment strategies. These agents have anti-tumor efficacy as a single modality and have demonstrated synergistic tumor killing when combined with radiation and/or chemotherapy. While cetuximab has been the primary anti-EGFR monoclonal antibody used in the US, variant anti-EGFR monoclonal antibodies have been used in several clinical studies and shown benefit with improved toxicity profiles. Next generation anti-EGFR monoclonal antibodies may demonstrate multi-target epitope recognition, enhanced immune cell stimulation, or conjugation with radioisotopes in order to improve clinical outcomes. Identification of the specific patient subset that would optimally benefit from anti-EGFR monoclonal antibodies remains an elusive goal.
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