1,113 research outputs found
Variational treatment of electron-polyatomic molecule scattering calculations using adaptive overset grids
The Complex Kohn variational method for electron-polyatomic molecule
scattering is formulated using an overset grid representation of the scattering
wave function. The overset grid consists of a central grid and multiple dense,
atom-centered subgrids that allow the simultaneous spherical expansions of the
wave function about multiple centers. Scattering boundary conditions are
enforced by using a basis formed by the repeated application of the free
particle Green's function and potential, on the overset
grid in a "Born-Arnoldi" solution of the working equations. The theory is shown
to be equivalent to a specific Pad\'e approximant to the -matrix, and has
rapid convergence properties, both in the number of numerical basis functions
employed and the number of partial waves employed in the spherical expansions.
The method is demonstrated in calculations on methane and CF in the
static-exchange approximation, and compared in detail with calculations
performed with the numerical Schwinger variational approach based on single
center expansions. An efficient procedure for operating with the free-particle
Green's function and exchange operators (to which no approximation is made) is
also described
EcoBot-II: An artificial agent with a natural metabolism
In this paper we report the development of the robot EcoBot-II, which exhibits a primitive form of artificial symbiosis. Microbial Fuel Cells (MFCs) were used as the onboard energy supply, which consisted of bacterial cultures from sewage sludge and employed oxygen from free air for oxidation at the cathode. EcoBot-II was able to perform sensing, information processing, communication and actuation when fed (amongst other substrates) with flies. This is the first robot in the world, to utilise unrefined substrate, oxygen from free air and exhibit four different types of behaviour
Modeling the evolution space of breakage fusion bridge cycles with a stochastic folding process
Breakage-Fusion-Bridge cycles in cancer arise when a broken segment of DNA is duplicated and an end from each copy joined together. This structure then 'unfolds' into a new piece of palindromic DNA. This is one mechanism responsible for the localised amplicons observed in cancer genome data. The process has parallels with paper folding sequences that arise when a piece of paper is folded several times and then unfolded. Here we adapt such methods to study the breakage-fusion-bridge structures in detail. We firstly consider discrete representations of this space with 2-d trees to demonstrate that there are 2^(n(n-1)/2) qualitatively distinct evolutions involving n breakage-fusion-bridge cycles. Secondly we consider the stochastic nature of the fold positions, to determine evolution likelihoods, and also describe how amplicons become localised. Finally we highlight these methods by inferring the evolution of breakage-fusion-bridge cycles with data from primary tissue cancer samples
Current Knowledge of Occupational Therapists in Wyoming Regarding the Affordable Care Act: A Quantitative Pilot Study
There is little information and research addressing occupational therapistsâ knowledge level and ability to implement the Affordable Care Act (ACA). This leads to the following problem statements: occupational therapistsâ knowledge level of and ability to implement changes to practice is unknown; furthermore, it is unknown if there is a difference in knowledge level based on professional membership, years of practice, and area of practice; and it is also unknown which aspects or areas of the ACA occupational therapists would like to know more about, and if there is a difference based upon professional membership, years of practice or area of practice.
The researchers created a quantitative, mail-based survey to gain insight to the problem statements. The researchers obtained approval from University of North Dakotaâs Institutional Review Board (IRB) to administer this survey to occupational therapists licensed in Wyoming, and mailed the survey. The researchers utilized SPSSÂŽ version 22 to test correlational statistics and data. Independent samples t-tests and ANOVA were utilized to test significance and analyze possible correlations.
The survey was sent to 281 Wyoming occupational therapists, with a total of 139 (49.47%) occupational therapists returning the survey. More of the occupational therapists (63 of 139 or 45.32%) rated their general knowledge of the ACA as a two on a scale of one to five than in any other area. When asked about specific areas of the ACA and its relationship to occupational therapy most occupational therapists (37%-46% or 52-64 of 139) rated themselves as having no knowledge or as a one out of five on each area. Additionally, most occupational therapists (approximately 49% or 67 of 139) rated their research habits at a one, indicating that they do not research current changes in legislation regarding the ACA. Furthermore, with the correlational statistics completed, relationships between variables were detected. Relationships were found with knowledge level of the ACA and occupational therapists working in orthopedics and geriatrics. Furthermore, pediatric practitioners reported a lower need for knowledge about the ACA than those in any other area (p\u3c.001); however, occupational therapists practicing in SNFs (33 of 130) reported a greater need for knowledge than those in other areas (p=.0465)
The Combinatorics of Tandem Duplication
Tandem duplication is an evolutionary process whereby a segment of DNA is replicated and proximally inserted. The different configurations that can arise from this process give rise to some interesting combinatorial questions. Firstly, we introduce an algebraic formalism to represent this process as a word producing automaton. The number of words arising from n tandem duplications can then be recursively derived. Secondly, each single word accounts for multiple evolutions. With the aid of a bi-coloured 2d- tree, a Hasse diagram corresponding to a partially ordered set is constructed, from which we can count the number of evolutions corresponding to a given word. Thirdly, we implement some subtree prune and graft operations on this structure to show that the total number of possible evolutions arising from n tandem duplications is . The space of structures arising from tandem duplication thus grows at a super-exponential rate with leading order term
Foot Muscle Energy Reserves in Diabetic Patients Without and With Clinical Peripheral Neuropathy
Objective: To investigate changes in the foot muscle energy reserves in diabetic non-neuropathic and neuropathic patients. Research Design and Methods: We measured the phosphocreatinine (PCr)/inorganic phosphate (Pi) ratio, total P concentration, and the lipid/water ratio in the muscles in the metatarsal head region using MRI spectroscopy in healthy control subjects and non-neuropathic and neuropathic diabetic patients. Results: The PCr/Pi ratio was higher in the control subjects (3.23 0.43) followed by the non-neuropathic group (2.61 0.36), whereas it was lowest in the neuropathic group (0.60 1.02) (P < 0.0001). There were no differences in total P concentration and lipid/water ratio between the control and non-neuropathic groups, but both measurements were different in the neuropathic group (P < 0.0001). Conclusions: Resting foot muscle energy reserves are affected before the development of peripheral diabetic neuropathy and are associated with the endothelial dysfunction and inflammation
Synthesis, characterization and biological evaluation of a new photoactive hydrogel against Gram-positive and Gram-negative bacteria
In 2013, the World Health Organization reported that 884 million people lack access to clean potable water. Photodynamic antimicrobial chemotherapy (PACT) is a very promising alternative to conventional antibiotics for the efficient inactivation of pathogenic microorganisms. We report the synthesis, characterization and antibacterial activity of a polyacrylamide-based hydrogel (7), with a new photoactive phenothiazinium compound (6) immobilized on it, to be used as a novel water-sterilizing device. The hydrogel was characterized by IR and scanning electron microscopy and incorporation of the dye confirmed by UV-visible spectroscopy. Antibacterial tests using the recombinant bioluminescent Gram-positive Staphylococcus aureus RN4220 and Gram-negative Escherichia coli DH5Îą were performed to assess the ability of the hydrogel to inactivate bacterial strains in solution. The hydrogel is characterized by a non-ordered microporous structure and is able to generate reactive oxygen species. The hydrogel is able to inactivate planktonic cells of the S. aureus and E. coli (3.3 log and 2.3 log killing, respectively) after 25 min of irradiation with white light at 14.5 mW cmâ2. The contact surface does not influence the kill rates while the killing rate increased by increasing the total amount of the hydrogel (0.27 log drop to 1.65 log drop with 0.5 mg cmâ3 to 2.5 mg cmâ3 of total amount of dye). The hydrogel was found to be active for four cycles, suggesting the possibility of reuse and it was shown to be active against both Gram-positive and Gram-negative species with no leaching of the active molecule
A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow
Š 2016 Author(s). The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and tes ting novel interventions in diseased tissue
Distinct glucose-dependent stress responses revealed by translational profiling in pancreatic β-cells
In pancreatic β-cells, following an acute (within 1âh) increase in glucose concentration, there are rapid changes in the expression of a large subset of proteins. The change in the expression of many of these proteins is mediated by a post-transcriptional mechanism through either increases or decreases in the rate of translation from pre-existing transcripts. These proteins, whose synthesis is rapidly up- or down-regulated in response to glucose, are likely important in mounting the correct response to changes in plasma glucose concentrations. However, the vast majority of these proteins remain unidentified. Therefore, in order to identify these proteins, we analysed changes in the levels of mRNAs associated with polysomes (i.e. actively translating mRNAs) isolated from mouse insulinoma 6 cells incubated at either 0¡5 or 20âmM glucose for 1âh. Changes in the levels of polysomal mRNAs in response to glucose were analysed using affymetrix oligonucleotide microarrays (translational profiling). This work revealed that, in response to a change in glucose concentration, the abundance of 313 transcripts associated with polysomes changed by more than 1¡5-fold, of which the abundance of 37 changed by more than twofold. The majority of these transcripts encoded proteins associated with metabolism or gene expression. More detailed analysis showed that a number of mRNAs encoding proteins associated with the induction of oxidative stress, including thioredoxin-2 and thioredoxin-interacting protein were rapidly redistributed onto heavier polysomes at high glucose concentration, indicating an increase in their expression. At low glucose concentration, when the general rate of protein synthesis is low, a number of mRNAs encoding integrated stress response proteins, including ATF4 and CHOP10, associate with heavier polysomes, indicating that their expression is up-regulated. In conclusion, translational profiling has revealed that, at either low or at high glucose concentration, β-cells rapidly increase the synthesis of a specific subset of proteins that are likely important in maintaining β-cell integrity and survival during conditions of nutritional stress
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