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Riess, Christian, Michael Simon Josef Walter, Stefan Weiherer, Tiffany Haas, Sebastian Haas und Alexandru Salceanu. „Heating an electric car with a biofuel operated heater during cold seasons – design, application and test“. ACTA IMEKO 7, Nr. 4 (09.01.2019): 48. http://dx.doi.org/10.21014/acta_imeko.v7i4.578.
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The automotive industry is currently undergoing far-reaching structural changes. Automobile manufacturers are pursuing intensive scientific research and technological development in the field of alternative drive systems, such as electric powertrains. If electric car batteries are charged with regenerative generated electricity, their emission output is zero (from a well-to-wheel view). Furthermore, electric drives have very high efficiency. At cold temperatures, however, the battery power drops due to energy-intensive loads, such as the heating of the passenger compartment, and this consequently reduces the range dramatically. Therefore, the focus of this research work is external energy supply for the required heat capacity. The auxiliary energy may be generated by renewable energy technologies in order to further improve the CO<sub>2</sub> balance of electric vehicles. The paper deals with the design, application, and testing of a biofuel-operated heater to heat the passenger compartment of a battery-powered electric car (a Renault ZOE R240). The practical use of the heating system is analyzed in several test drives, performed during winter 2018. The results as well as the range extension of the electric car that can be achieved by substituting the on-board heating system by the fuel-operated heater are quantified herein.
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Li, Hao, Shuo Chen, Xiang Wu und Guojun Tan. „Model Predictive Control Method with Constant Switching Frequency to Reduce Common-Mode Voltage for PMSM Drives“. Journal of Electrical and Computer Engineering 2018 (08.10.2018): 1–12. http://dx.doi.org/10.1155/2018/1090452.
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A model predictive control method to reduce the common-mode voltage (MPC-RCMV) with constant switching frequency for PMSM drives is proposed in this paper. Four nonzero VVs are adopted in future control period and the switching sequence is designed to ensure the switching frequency is fixed and equal to the control frequency. By substituting the finite-control nonzero voltage vectors in the current predictive model, a current predictive error space vector diagram is obtained to determine the adopted four VVs. The duty ratio calculating method for the selected four VVs is studied. Compared with the conventional MPC-RCMV method, the current and torque ripples are greatly reduced and the switching frequency is fixed. The simulation and experiment results validate the effectiveness of the proposed method.
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Laleman, Wim, Joan Claria, Schalk Van der Merwe, Richard Moreau und Jonel Trebicka. „Systemic Inflammation and Acute-on-Chronic Liver Failure: Too Much, Not Enough“. Canadian Journal of Gastroenterology and Hepatology 2018 (01.08.2018): 1–10. http://dx.doi.org/10.1155/2018/1027152.
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ACLF is a specific, but complex and multifactorial form of acute decompensation of cirrhosis and is characterized by an extraordinary dynamic natural course, rapidly evolving organ failure, and high short-term mortality. Dysbalanced immune function is central to its pathogenesis and outcome with an initial excessive systemic inflammatory response that drives organ failure and mortality. Later in its course, immuno-exhaustion/immunoparalysis prevails predisposing the patient to secondary infectious events and reescalation in end-organ dysfunction and mortality. The management of patients with ACLF is still poorly defined. However, as its pathophysiology is gradually being unravelled, potential therapeutic targets emerge that warrant further study such as restoring or substituting albumin via plasma exchange or via albumin dialysis and evaluating usefulness of TLR4 antagonists, modulators of gut dysbiosis (pre- or probiotics), and FXR-agonists.
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Rogozin, Igor B., Frida Belinky, Vladimir Pavlenko, Svetlana A. Shabalina, David M. Kristensen und Eugene V. Koonin. „Evolutionary switches between two serine codon sets are driven by selection“. Proceedings of the National Academy of Sciences 113, Nr. 46 (31.10.2016): 13109–13. http://dx.doi.org/10.1073/pnas.1615832113.
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Serine is the only amino acid that is encoded by two disjoint codon sets so that a tandem substitution of two nucleotides is required to switch between the two sets. Previously published evidence suggests that, for the most evolutionarily conserved serines, the codon set switch occurs by simultaneous substitution of two nucleotides. Here we report a genome-wide reconstruction of the evolution of serine codons in triplets of closely related species from diverse prokaryotes and eukaryotes. The results indicate that the great majority of codon set switches proceed by two consecutive nucleotide substitutions, via a threonine or cysteine intermediate, and are driven by selection. These findings imply a strong pressure of purifying selection in protein evolution, which in the case of serine codon set switches occurs via an initial deleterious substitution quickly followed by a second, compensatory substitution. The result is frequent reversal of amino acid replacements and, at short evolutionary distances, pervasive homoplasy.
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Rubel, Robiul Islam, Md Jafor Iqball und Md Emdadul Hoque. „Analysis of a CNG Driven Three Wheeler Drive Shaft“. Applied Mechanics and Materials 860 (Dezember 2016): 93–98. http://dx.doi.org/10.4028/www.scientific.net/amm.860.93.
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CNG driven three wheeler vehicles is seen to carrying passenger around Bangladesh and vary favorable as public or private hired vehicle. Its drive shaft is a vital component for transmitting power from engine to wheel rotates at around 4000-5000 rpm. Most shafts undergo varying range of loads including bending, torsion and axial simultaneously. Therefore, the shaft fails frequently. But the problem of its replacement is difficult. It is imported from abroad; usually from the origin country of a specific model which makes its interchangeability exorbitant to the owner but also time consuming due to unavailability throughout the country. Substituting high cost unoriginal drive shaft by locally made shaft is an important criterion for lowering the maintenance cost. In this work an attempt has been made to estimate the deflection, stresses under subjected loads using FEA in ANSYS. The static structural analysis gives deflection and stresses. Modal analysis shows the nature of frequency and the maximum permissible rotating speed.
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Kodkin, Vladimir L., Aleksandr Sergeevich Anikin und Aleksandr A. Baldenkov. „The dynamics identification of asynchronous electric drives via frequency response“. International Journal of Power Electronics and Drive Systems (IJPEDS) 10, Nr. 1 (01.03.2019): 66. http://dx.doi.org/10.11591/ijpeds.v10.i1.pp66-73.
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<span>The article substantiates the necessity of identifying the dynamics of asynchronous electric drives with frequency control. It is proposed to use nonlinear transfer functions and the formula of a family of frequency responses of an electric drive, depending on the frequency of the stator voltage and slip. Experiments and simulations confirming theoretical conclusions are presented. The frequency responses of the drive of the stand calculated by the proposed method allowed to explain those problems of frequency control that were not explained by traditional methods - analytical, vector diagrams, substitution schemes, etc. This same technique allowed us to formulate a structural correction of the asynchronous electric drives. In contrast to the previously published research materials of asynchronous electric drives, a detailed qualitative analysis of the obtained nonlinear frequency responses and the interrelation of these characteristics with experimental results is shown for the first time in the article.</span>
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Rimmelzwaan, G. F., E. G. M. Berkhoff, N. J. Nieuwkoop, D. J. Smith, R. A. M. Fouchier und A. D. M. E. Osterhaus. „Full restoration of viral fitness by multiple compensatory co-mutations in the nucleoprotein of influenza A virus cytotoxic T-lymphocyte escape mutants“. Journal of General Virology 86, Nr. 6 (01.06.2005): 1801–5. http://dx.doi.org/10.1099/vir.0.80867-0.
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Amino acid substitutions have been identified in the influenza A virus nucleoprotein that are associated with escape from recognition by virus-specific cytotoxic T lymphocytes (CTLs). One of these is the arginine-to-glycine substitution at position 384 (R384G). This substitution alone, however, is detrimental to viral fitness, which is overcome in part by the functionally compensating co-mutation E375G. Here, the effect on viral fitness of four other co-mutations associated with R384G was investigated by using plasmid-driven rescue of mutant viruses. Whilst none of these alternative co-mutations alone compensated functionally for the detrimental effect of the R384G substitution, the M239V substitution improved viral fitness of viruses containing 375G and 384R. The nucleoprotein displays unexpected flexibility to overcome functional constraints imposed by CTL epitope sequences, allowing influenza viruses to escape from specific CTLs.
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Karpukhina, Natalia, Robert V. Law und Robert G. Hill. „Solid State NMR Study of Calcium Fluoroaluminosilicate Glasses“. Advanced Materials Research 39-40 (April 2008): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.25.
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Fluorine containing calcium aluminosilicate glasses are widely used for a number of technological applications including dental cements, mould fluxes in steel making and in a variety of glass-ceramic systems. Despite of their importance these systems remain quite poorly understood with respect to their composition. To address this question a glass composition corresponding to the equimolar binary system anorthite−fluorite (Ca2Al2Si2O8−CaF2) was chosen as a base point for two series of compositions. One of the series is designed on the anorthite stoichiometry and considered as classically charge balanced. Another series starts from the fluorine free composition of the anorthite−lime (Ca2Al2Si2O8−CaO) stoichiometry and, therefore, is characterized by a disrupted network with at least one non-bridging oxygen (NBO) attached to silicon. A multinuclear 19F, 27Al, 29Si solid state NMR study of the glasses was undertaken. It is shown that in both series fluorine is predominantly coordinated by calcium, F−Ca(n), and in addition interacts with aluminium forming Al−F−Ca(n) complexes, where n denotes the number of first neighbouring calcium cations. Small amounts of high coordinated aluminium grows with increasing fluoride content in both glass series. However, the high coordinated aluminium may not be solely due to the formation of the Al−F−Ca(n) complexes. Glasses of the first series displayed systematic upfield shift of 29Si NMR resonance while substituting fluoride for oxide, starting from the fluorine free composition. This upfield shift is interpreted as the lack of cations in the network, due to formation of the F−Ca(n), which drives silicon network to polymerize toward a higher Qn structure. Contrary to the first series, the 29Si NMR resonance remains constant for fluorine containing compositions of the second series but differs downfield from the initial anorthite glass. The latter is explained by the excess of cations in the network due to addition of the fluorite resulting in formation of NBO on the silicon. Binding of fluorine with silicon is considered negligible in these systems. Thus, fluorine and calcium both define the degree of network polymerization and are considered as a cause for the changes in silicon and aluminium networks.
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Chappell, Helen F., Ravin Jugdaohsingh und Jonathan J. Powell. „Physiological silicon incorporation into bone mineral requires orthosilicic acid metabolism to SiO 4 4−“. Journal of The Royal Society Interface 17, Nr. 167 (Juni 2020): 20200145. http://dx.doi.org/10.1098/rsif.2020.0145.
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Under physiological conditions, the predominant form of bioavailable silicon (Si) is orthosilicic acid (OSA). In this study, given Si's recognized positive effect on bone growth and integrity, we examined the chemical form and position of this natural Si source in the inorganic bone mineral hydroxyapatite (HA). X-ray diffraction (XRD) of rat tibia bone mineral showed that the mineral phase was similar to that of phase-pure HA. However, theoretical XRD patterns revealed that at the levels found in bone, the ‘Si effect’ would be virtually undetectable. Thus we used first principles density functional theory calculations to explore the energetic and geometric consequences of substituting OSA into a large HA model. Formation energy analysis revealed that OSA is not favourable as a neutral interstitial substitution but can be incorporated as a silicate ion substituting for a phosphate ion, suggesting that incorporation will only occur under specific conditions at the bone-remodelling interface and that dietary forms of Si will be metabolized to simpler chemical forms, specifically SiO 4 4 − . Furthermore, we show that this substitution, at the low silicate concentrations found in the biological environment, is likely to be a driver of calcium phosphate crystallization from an amorphous to a fully mineralized state.
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Moutinho, Ana Filipa, Thomas Bataillon und Julien Y. Dutheil. „Variation of the adaptive substitution rate between species and within genomes“. Evolutionary Ecology 34, Nr. 3 (14.12.2019): 315–38. http://dx.doi.org/10.1007/s10682-019-10026-z.
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AbstractThe importance of adaptive mutations in molecular evolution is extensively debated. Recent developments in population genomics allow inferring rates of adaptive mutations by fitting a distribution of fitness effects to the observed patterns of polymorphism and divergence at sites under selection and sites assumed to evolve neutrally. Here, we summarize the current state-of-the-art of these methods and review the factors that affect the molecular rate of adaptation. Several studies have reported extensive cross-species variation in the proportion of adaptive amino-acid substitutions (α) and predicted that species with larger effective population sizes undergo less genetic drift and higher rates of adaptation. Disentangling the rates of positive and negative selection, however, revealed that mutations with deleterious effects are the main driver of this population size effect and that adaptive substitution rates vary comparatively little across species. Conversely, rates of adaptive substitution have been documented to vary substantially within genomes. On a genome-wide scale, gene density, recombination and mutation rate were observed to play a role in shaping molecular rates of adaptation, as predicted under models of linked selection. At the gene level, it has been reported that the gene functional category and the macromolecular structure substantially impact the rate of adaptive mutations. Here, we deliver a comprehensive review of methods used to infer the molecular adaptive rate, the potential drivers of adaptive evolution and how positive selection shapes molecular evolution within genes, across genes within species and between species.
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Hicks, Daniel L. „Consumption Volatility, Marketization, and Expenditure in an Emerging Market Economy“. American Economic Journal: Macroeconomics 7, Nr. 2 (01.04.2015): 95–123. http://dx.doi.org/10.1257/mac.20120222.
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In response to income fluctuations, households smooth consumption by substituting between market expenditure and time inputs. This paper provides evidence of this substitution in the context of food consumption over transitory and permanent income fluctuations in Mexico. Household time investments drive a wedge between consumption and expenditure, amplifying measured expenditure volatility. Volatility decompositions for Mexico and the United States suggest that the extent of bias in expenditure-based measures induced by changes in marketization is relatively larger in the Mexican setting. These findings imply that volatility comparisons between commodities or across countries are misleading when consumption measures ignore home production. (JEL D12, D91, E21, E32, O11, O12)
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Bridgford, Jessica L., Su Min Lee, Christine M. M. Lee, Paola Guglielmelli, Elisa Rumi, Daniela Pietra, Stephen Wilcox et al. „Novel drivers and modifiers of MPL-dependent oncogenic transformation identified by deep mutational scanning“. Blood 135, Nr. 4 (23.01.2020): 287–92. http://dx.doi.org/10.1182/blood.2019002561.
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Abstract The single transmembrane domain (TMD) of the human thrombopoietin receptor (TpoR/myeloproliferative leukemia [MPL] protein), encoded by exon 10 of the MPL gene, is a hotspot for somatic mutations associated with myeloproliferative neoplasms (MPNs). Approximately 6% and 14% of JAK2 V617F− essential thrombocythemia and primary myelofibrosis patients, respectively, have “canonical” MPL exon 10 driver mutations W515L/K/R/A or S505N, which generate constitutively active receptors and consequent loss of Tpo dependence. Other “noncanonical” MPL exon 10 mutations have also been identified in patients, both alone and in combination with canonical mutations, but, in almost all cases, their functional consequences and relevance to disease are unknown. Here, we used a deep mutational scanning approach to evaluate all possible single amino acid substitutions in the human TpoR TMD for their ability to confer cytokine-independent growth in Ba/F3 cells. We identified all currently recognized driver mutations and 7 novel mutations that cause constitutive TpoR activation, and a much larger number of second-site mutations that enhance S505N-driven activation. We found examples of both of these categories in published and previously unpublished MPL exon 10 sequencing data from MPN patients, demonstrating that some, if not all, of the new mutations reported here represent likely drivers or modifiers of myeloproliferative disease.
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Cox, Andrea L., Timothy Mosbruger, Qing Mao, Zhi Liu, Xiao-Hong Wang, Hung-Chih Yang, John Sidney et al. „Cellular immune selection with hepatitis C virus persistence in humans“. Journal of Experimental Medicine 201, Nr. 11 (06.06.2005): 1741–52. http://dx.doi.org/10.1084/jem.20050121.
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Hepatitis C virus (HCV) infection frequently persists despite substantial virus-specific cellular immune responses. To determine if immunologically driven sequence variation occurs with HCV persistence, we coordinately analyzed sequence evolution and CD8+ T cell responses to epitopes covering the entire HCV polyprotein in subjects who were followed prospectively from before infection to beyond the first year. There were no substitutions in T cell epitopes for a year after infection in a subject who cleared viremia. In contrast, in subjects with persistent viremia and detectable T cell responses, we observed substitutions in 69% of T cell epitopes, and every subject had a substitution in at least one epitope. In addition, amino acid substitutions occurred 13-fold more often within than outside T cell epitopes (P < 0.001, range 5–38). T lymphocyte recognition of 8 of 10 mutant peptides was markedly reduced compared with the initial sequence, indicating viral escape. Of 16 nonenvelope substitutions that occurred outside of known T cell epitopes, 8 represented conversion to consensus (P = 0.015). These findings reveal two distinct mechanisms of sequence evolution involved in HCV persistence: viral escape from CD8+ T cell responses and optimization of replicative capacity.
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Bansal, Saurabh, und James S. Dyer. „Planning for End-User Substitution in Agribusiness“. Operations Research 68, Nr. 4 (Juli 2020): 1000–1019. http://dx.doi.org/10.1287/opre.2019.1943.
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Saurabh Bansal and James S. Dyer study a common problem in the commercial agribusiness market, where farmers have a preference for a farm input such as a seed based on a fit with their geographical location but are also willing to accept a closely related substitute. Such consumer-driven choices may not be adequately represented by traditional models that maximize the profit of a firm that seeks to make substitutions while maximizing its profit. They use a set of recent results for evaluations of moments over polyhedra to determine the exact inventory levels a firm should keep of substitutable products. Using proprietary data from a large firm in this domain, they highlight the role of geographical and climate-related factors that affect product substitution in the agribusiness industry and identify specific regions in the United States where product substitution is a source of substantial revenue for firms.
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Malcorps, Wesley, Björn Kok, Mike van‘t Land, Maarten Fritz, Davy van Doren, Kurt Servin, Paul van der Heijden et al. „The Sustainability Conundrum of Fishmeal Substitution by Plant Ingredients in Shrimp Feeds“. Sustainability 11, Nr. 4 (25.02.2019): 1212. http://dx.doi.org/10.3390/su11041212.
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Aquaculture is central in meeting expanding global demands for shrimp consumption. Consequently, increasing feed use is mainly responsible for the overall environmental impact of aquaculture production. Significant amounts of fishmeal are included in shrimp diets, causing dependency on finite marine resources. Driven by economic incentives, terrestrial plant ingredients are widely viewed as sustainable alternatives. Incremental fishmeal substitution by plant ingredients in shrimp feed was modeled and effects on marine and terrestrial resources such as fish, land, freshwater, nitrogen, and phosphorus were assessed. We find that complete substitution of 20–30% fishmeal totals could lead to increasing demand for freshwater (up to 63%), land (up to 81%), and phosphorus (up to 83%), while other substitution rates lead to proportionally lower impacts. These findings suggest additional pressures on essential agricultural resources with associated socio-economic and environmental effects as a trade-off to pressures on finite marine resources. Even though the production of shrimp feed (or aquafeed in general) utilizes only a small percentage of the global crop production, the findings indicate that the sustainability of substituting fishmeal by plant ingredients should not be taken for granted, especially since aquaculture has been one of the fastest growing food sectors. Therefore, the importance of utilizing by-products and novel ingredients such as microbial biomass, algae, and insect meals in mitigating the use of marine and terrestrial resources is discussed.
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Xin, H., Q. Pang, D. L. Gao, L. Li, P. Zhang und J. Zhao. „Mn ions' site and valence in PbTiO3 based on the native vacancy defects“. Condensed Matter Physics 24, Nr. 2 (2021): 23705. http://dx.doi.org/10.5488/cmp.24.23705.
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Mn ions' doping site and valence were studied in PbTiO3 (PT) with the native vacancy defects by the first-principles calculations. Firstly, the native vacancy defects of Pb, O and Ti in PT were investigated and it was found that Pb vacancy is preferred to others. And then the growth of Mn doped PT should be preferred to Mn ion substituting for an A-site Pb ion with +3 valence when Pb is deficient under equilibrium conditions driven solely by minimization of the formation energy, and this could result in a larger lattice distortion of PT. In addition, when Mn enters the Pb site, the electronegativity of O becomes weaker which makes the domain movement easier in PT to improve the performance of PT, while Mn ion substitution for a B-site Ti ion is the opposite.
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Kulchania, Manoj. „Catering driven substitution in corporate payouts“. Journal of Corporate Finance 21 (Juni 2013): 180–95. http://dx.doi.org/10.1016/j.jcorpfin.2013.02.003.
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Angrist, Joshua D., Sydnee Caldwell und Jonathan V. Hall. „Uber versus Taxi: A Driver’s Eye View“. American Economic Journal: Applied Economics 13, Nr. 3 (01.07.2021): 272–308. http://dx.doi.org/10.1257/app.20190655.
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Rideshare drivers pay a proportion of their fares to a ride-hailing platform operator, a commission-based compensation model used by many service providers. To Uber drivers, this commission is known as the Uber fee. By contrast, traditional taxi drivers in most US cities make a fixed payment independent of their earnings, usually a weekly or daily medallion lease, keeping every fare dollar net of lease costs and other expenses. We assess these compensation models using an experiment that offered random samples of Boston Uber drivers opportunities to lease a virtual taxi medallion that eliminates the Uber fee. Some drivers were offered a negative fee. Drivers’ labor supply response to our offers reveals a large intertemporal substitution elasticity, on the order of 1.2, and higher for those who accept lease contracts. At the same time, our virtual lease program was undersubscribed: many drivers who would have benefited from buying an inexpensive lease chose to sit out. We use these results to compute the average compensation required to make drivers indifferent between rideshare and taxi-style compensation contracts. The results suggest that rideshare drivers gain considerably from the opportunity to drive without leasing. (JEL J22, J31, L84, L92)
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Zhang, Ming Zhe, Wei Wang, Dong Ning Su, Kang Min Zhong und Zhi Ming Sui. „Mechanical-Electronic-Hydraulic Integration: Light Load Linear Reciprocating Motion Device Having Variable Frequency, Displacement and Velocity“. Advanced Materials Research 279 (Juli 2011): 377–81. http://dx.doi.org/10.4028/www.scientific.net/amr.279.377.
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The light load linear reciprocating motion device driven by a small-size pneumatic cylinder is most economical, but its velocity and location precision is not good. When substituting the drive for small-size hydraulic cylinder, the significant shortcoming is environmental pollution. If the motion is achieved through rolling screw-nut mechanism driven by stepping motor, the space layout is very inconvenient. A light load linear reciprocating motion device integrating mechanical, electronic and hydraulic technology is designed. In this device, the motion is achieved through short-stroke rolling screw-nut mechanism driven by stepping motor, and then amplified by a splendid internal reflux area effect stroke amplifier. This device has the following noticeable advantages: (1) The location of output hydraulic cylinder is as convenient as common pneumatic or hydraulic cylinder. (2) The frequency, displacement and velocity of reciprocating motion can be altered convenient by programming. (3) Higher position precision. (4) The hydraulic fluid in the device is enclosed, so there is no environmental pollution causing by oil leakage and volatilization.
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Fukuoka, Hajime, Toshiharu Yakushi und Michio Homma. „Concerted Effects of Amino Acid Substitutions in Conserved Charged Residues and Other Residues in the Cytoplasmic Domain of PomA, a Stator Component of Na+-Driven Flagella“. Journal of Bacteriology 186, Nr. 20 (15.10.2004): 6749–58. http://dx.doi.org/10.1128/jb.186.20.6749-6758.2004.
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ABSTRACT PomA is a membrane protein that is one of the essential components of the sodium-driven flagellar motor in Vibrio species. The cytoplasmic charged residues of Escherichia coli MotA, which is a PomA homolog, are believed to be required for the interaction of MotA with the C-terminal region of FliG. It was previously shown that a PomA variant with neutral substitutions in the conserved charged residues (R88A, K89A, E96Q, E97Q, and E99Q; AAQQQ) was functional. In the present study, five other conserved charged residues were replaced with neutral amino acids in the AAQQQ PomA protein. These additional substitutions did not affect the function of PomA. However, strains expressing the AAQQQ PomA variant with either an L131F or a T132M substitution, neither of which affected motor function alone, exhibited a temperature-sensitive (TS) motility phenotype. The double substitutions R88A or E96Q together with L131F were sufficient for the TS phenotype. The motility of the PomA TS mutants immediately ceased upon a temperature shift from 20 to 42°C and was restored to the original level approximately 10 min after the temperature was returned to 20°C. It is believed that PomA forms a channel complex with PomB. The complex formation of TS PomA and PomB did not seem to be affected by temperature. Suppressor mutations of the TS phenotype were mapped in the cytoplasmic boundaries of the transmembrane segments of PomA. We suggest that the cytoplasmic surface of PomA is changed by the amino acid substitutions and that the interaction of this surface with the FliG C-terminal region is temperature sensitive.
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Zhou, Yancong, und Junqing Sun. „Inventory Decisions in a Product-Updated System with Component Substitution and Product Substitution“. Discrete Dynamics in Nature and Society 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/136074.
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Substitution behaviors happen frequently when demands are uncertain in a production inventory system, and it has attracted enough attention from firms. Related researches can be clearly classified into firm-driven substitution and customer-driven substitution. However, if production inventory is stock-out when a firm updates its product, the firm may use a new generation product to satisfy the customer’s demand of old generation product or use updated component to substitute old component to satisfy production demand. Obviously, two cases of substitution exist simultaneously in the product-updated system when an emergent shortage happens. In this paper, we consider a component order problem with component substitution and product substitution simultaneously in a product-updated system, where the case of firm-driven substitution or customer-driven substitution can be reached by setting different values for two system parameters. Firstly, we formulate the problem into a two-stage dynamic programming. Secondly, we give the optimal decisions about assembled quantities of different types of products. Next, we prove that the expected profit function is jointly concave in order quantities and decrease the feasible domain by determining some bounds for decision variables. Finally, some management insights about component substitution and product substitution are investigated by theoretical analysis method.
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Diez, A. B., V. L. Alvarez, D. F. García und H. Lόpez. „The Implementation of AC-Drives in Substitution of DC-Drives in the Steel Industry“. IFAC Proceedings Volumes 22, Nr. 11 (September 1989): 155–60. http://dx.doi.org/10.1016/s1474-6670(17)53103-1.
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Jianhong, Wang. „Dynamic Programming in Data Driven Model Predictive Control?“ WSEAS TRANSACTIONS ON SYSTEMS 20 (21.07.2021): 170–77. http://dx.doi.org/10.37394/23202.2021.20.19.
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In this short note, one data driven model predictive control is studied to design the optimal control sequence. The idea of data driven means the actual output value in cost function for model predictive control is identi_ed through input-output observed data in case of unknown but bounded noise and martingale di_erence sequence. After substituting the identi_ed actual output in cost function, the total cost function in model predictive control is reformulated as the other standard form, so that dynamic programming can be applied directly. As dynamic programming is only used in optimization theory, so to extend its advantage in control theory, dynamic programming algorithm is proposed to construct the optimal control sequence. Furthermore, stability analysis for data drive model predictive control is also given based on dynamic programming strategy. Generally, the goal of this short note is to bridge the dynamic programming, system identi_cation and model predictive control. Finally, one simulation example is used to prove the e_ciency of our proposed theory
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Song, Zehua, Jérôme Clain, Bogdan I. Iorga, Zhou Yi, Nicholas Fisher und Brigitte Meunier. „Saccharomyces cerevisiae-Based Mutational Analysis of thebc1Complex QoSite Residue 279 To Study the Trade-Off between Atovaquone Resistance and Function“. Antimicrobial Agents and Chemotherapy 59, Nr. 7 (27.04.2015): 4053–58. http://dx.doi.org/10.1128/aac.00710-15.
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ABSTRACTThebc1complex is central to mitochondrial bioenergetics and the target of the antimalarial drug atovaquone that binds in the quinol oxidation (Qo) site of the complex. Structural analysis has shown that the Qosite residue Y279 (Y268 inPlasmodium falciparum) is key for atovaquone binding. Consequently, atovaquone resistance can be acquired by mutation of that residue. In addition to the probability of amino acid substitution, the level of atovaquone resistance and the loss ofbc1complex activity that are associated with the novel amino acid would restrict the nature of resistance-driven mutations occurring on atovaquone exposure in native parasite populations. Using the yeast model, we characterized the effect of all the amino acid replacements resulting from a single nucleotide substitution at codon 279: Y279C, Y279D, Y279F, Y279H, Y279N, and Y279S (Y279C, D, F, H, N, and S). Two residue changes that required a double nucleotide substitution, Y279A and W, were added to the series. We found that mutations Y279A, C, and S conferred high atovaquone resistance but decreased the catalytic activity. Y279F had wild-type enzymatic activity and sensitivity to atovaquone, while the other substitutions caused a dramatic respiratory defect. The results obtained with the yeast model were examined in regard to atomic structure and compared to the reported data on the evolution of acquired atovaquone resistance inP. falciparum.
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Yao, Jiansheng, und Shirley Gillam. „Mutational Analysis, Using a Full-Length Rubella Virus cDNA Clone, of Rubella Virus E1 Transmembrane and Cytoplasmic Domains Required for Virus Release“. Journal of Virology 73, Nr. 6 (01.06.1999): 4622–30. http://dx.doi.org/10.1128/jvi.73.6.4622-4630.1999.
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ABSTRACT We report on the construction of a full-length cDNA clone, pBRM33, derived from wild-type rubella virus M33 strain. The RNA transcripts synthesized in vitro from pBRM33 are highly infectious, and the viruses produced retain the phenotypic characteristics of the parental M33 virus in growth rate and plaque size. This cDNA clone was used to study the role of E1 transmembrane and cytoplasmic domains in virus assembly by site-directed mutagenesis. Three different alanine substitutions were introduced in the transmembrane domain of E1. These included substitution of leucine 464, cysteine 466, cysteine 467, and both cysteines 466 and 467 to alanine. In the E1 cytoplasmic domain, cysteine 470 and leucine 471 were altered to alanine. We found that these mutations did not significantly affect viral RNA replication, viral structural protein synthesis and transport, or E2/E1 heterodimer formation. Except for the substitution of cysteine 470, these mutations did, however, lead to a reduction in virus release. Substitution of cysteine 467 in the transmembrane region and of leucine 471 in the cytoplasmic domain dramatically reduced virus yield, resulting in the production of only 1 and 10% of the parental virus yield, respectively, in a parallel infection. These data show that E1 transmembrane and cytoplasmic domains play an important role in late stages of virus assembly, possibly during virus budding, consistent with earlier studies indicating that the E1 cytoplasmic domain may interact with nucleocapsids and that this interaction drives virus budding.
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Cherniy, Sergey Grigoryevich, Aleksandr Sergeevich Sobolev und Pavel Andreevich Erofeev. „Developing simulation models for precise adjustment and debugging of ship frequency inverters“. Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2020, Nr. 4 (18.11.2020): 95–104. http://dx.doi.org/10.24143/2073-1574-2020-4-95-104.
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The paper describes a variable frequency drive which consists of two elements: an electric drive (synchronous or asynchronous electric drives, that is, drives powered by alternating current are used in capacity of it), and a frequency converter able to control the amplitude and frequency of the voltage supplied to the drive. It becomes possible to control the speed of rotation of the electric motor and the torque on its shaft. The most optimal energy efficiency when using compressor units is achieved under the operating mode when its average daily load factor makes at least 85%. Under the mentioned operating mode fluctuations during the compressed air consumption will be minimal, and the most stable operation of the compressor at its rated nominal power is ensured. In practice, no more than 15% of all the industrial compressors are operated in such operating mode. For 85% of the compressor units the question of improving energy efficiency by regulating its capacity remains open. The method of capacity regulation by using a frequency converter is currently the most optimal and perfect, because adjusting the parameters of the electric drive in this way, the most accurate regulation of the compressed air pressure is provided, which allows reducing the energy consumption in the compressed air injection process, as well as extending the service life of the equipment used. There has been considered a device with frequency control of a compressor unit, debugging of which was carried out on the basis of a mathematical model, which allows choosing the most optimal parameters for frequency control of an electric drive of a compressor unit in order to increase energy efficiency. The analysis of all the advantages and disadvantages of frequency regulation is being carried out, as well as a comparative analysis for selecting the optimal frequency converter in terms of the import substitution
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Ávila-Torres, Yenny, Lázaro Huerta und Noráh Barba-Behrens. „XPS-Characterization of Heterometallic Coordination Compounds with Optically Active Ligands“. Journal of Chemistry 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/370637.
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The heterometallic optical complexes [Cu2Co(S,S(+)cpse)3(H2O)3]·4H2O (1) and [Cu2Ni(S,S(+)cpse)3(H2O)3]·10H2O (2) were obtained from the mononuclear copper(II) compound by the addition of nickel(II) or cobalt(II) chlorides, where (H2cpse) is the acetyl amino alcohol derivative N-[2-hydroxy-1(R)-methyl-2(R)-phenylethyl]-N-methylglycine. In comparison with the homotrinuclear copper(II) compound [Cu3(S,S(+)cpse)3(H2O)3]·8H2O reported previously, the substitution of a copper(II) atom by one cobalt(II) ion gave place to a heterotrinuclear compound1, which presents ferromagnetic-antiferromagnetic behaviour. When substituting a copper(II) by a nickel(II) ion, the trinuclear compound2showed an antiferromagnetic coupling. The magnetic behaviour of the heterotrinuclear compounds is driven by the nature of the metal ion which was introduced in the copper(II) triangular array. The ligand and its coordination compounds were characterized by IR, UV-Vis-NIR. Their chemical was confirmed by photoelectron spectroscopy (XPS).
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Fares, Aline Fusco, Sebastiao N. Martins-Filho, Quan Li, Andrew Seto, Erin L. Stewart, Tong Zhang, Sally CM Lau et al. „Genomic analysis of driver-negative lung adenocarcinoma (LA) in lifetime never smokers.“ Journal of Clinical Oncology 38, Nr. 15_suppl (20.05.2020): 3571. http://dx.doi.org/10.1200/jco.2020.38.15_suppl.3571.
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3571 Background: Genomic events giving rise to driver negative LA in never smokers remain elusive. Here we report results of whole exome sequencing (WES) and targeted RNA sequencing in NS who had no mutation drivers found on routine clinical testing by targeted next generation sequencing (NGS). Methods: The cohort of never smokers with EGFR/ALK negative LA by clinical biomarker testing at Princess Margaret Cancer Centre, were first subjected to various clinical NGS profiling platforms (table). Where tissue was available, those negative for potential drivers in the clinical NGS then underwent WES (mean coverage > 200x) and Oncomine comprehensive v.3 RNA sequencing. We analyzed mutational signatures (MS) of the driver negative cohort based on the COSMIC catalog and assessed the median tumor mutation burden (mTMB mut/Mb -Megabase) in cases without a smoking MS, to avoid confounders. Results: Of 159 never smokers profiled with clinical NGS, potential drivers were found in 86 (54%): 75 (87%) with mutations in known LA driver genes and 11 (13%) with fusions. Among the remaining never smokers that tested negative by clinical NGS, 35 (48%) had available tissue for further testing. The Oncomine panel identified 9 cases (25%) with fusions or MET exon14 mutation (n = 7). Within the driver negative group, 24 (92%) underwent WES. Three tumors had WES base substitution patterns that were consistent with a smoking-related MS (MS4). Twenty-one patients exhibited signatures found common across all cancer types (MS 5), associated with DNA mismatch repair (MS 6, MS 20) or APOBEC over-activation (MS 2, MS13). In the driver-negative group, we identified 7 pts with somatic mutations in the KMT2 family (4 KMT2C, 4 KMT2A, 1 KMT2D), known for putative tumor suppressors and histone methyltransferases. mTMB on the driver negative group was 1.92, while one outlier with APOBEC MS and KMT2C/A mutations had a TMB of 16.8. Conclusions: Never smokers with driver negative LA are a heterogeneous group, with different MS and a wide TMB range. Mutations on KMT2 family are frequently found in driver negative LA in never smokers and warrant further investigations. [Table: see text]
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Caves, Kevin W. „Quantifying price-driven wireless substitution in telephony“. Telecommunications Policy 35, Nr. 11 (Dezember 2011): 984–98. http://dx.doi.org/10.1016/j.telpol.2011.08.001.
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PINTUS, PATRICK A. „EXPECTATIONS-DRIVEN FLUCTUATIONS WHEN FACTOR UTILIZATION IS VARIABLE“. Macroeconomic Dynamics 8, Nr. 1 (30.01.2004): 3–26. http://dx.doi.org/10.1017/s1365100504020255.
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The present paper studies the influence of variable labor utilization on local indeterminacy and expectations-driven fluctuations, in one-sector models with (nearly) constant returns to scale. It is shown that, in comparison to the configuration of constant input utilization, considering variable utilization reduces the actual possibilities of factor substitution and, consequently, the range of input substitution elasticities that are compatible with endogenous fluctuations. In particular, local indeterminacy and expectations-driven fluctuations occur only if utilization rates are sufficiently inelastic, whereas local determinacy prevails when utilization is highly elastic. However, accounting for the fact that variable utilization reduces theeffectiveelasticity of capital/labor substitution leads us to argue that expectations-driven fluctuations are more plausible because they require larger elasticities ofapparentinput substitution. In contrast with the recent literature, the analysis does not rely on significantly increasing returns to scale in production. Accordingly, the results are not at variance with recent empirical studies emphasizing the importance of variable utilization and denying the evidence of large increasing returns.
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Dragomir, Ionut, Adnan Akbar, John W. Cassidy, Nirmesh Patel, Harry W. Clifford und Gianmarco Contino. „Identifying Cancer Drivers Using DRIVE: A Feature-Based Machine Learning Model for a Pan-Cancer Assessment of Somatic Missense Mutations“. Cancers 13, Nr. 11 (03.06.2021): 2779. http://dx.doi.org/10.3390/cancers13112779.
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Sporadic cancer develops from the accrual of somatic mutations. Out of all small-scale somatic aberrations in coding regions, 95% are base substitutions, with 90% being missense mutations. While multiple studies focused on the importance of this mutation type, a machine learning method based on the number of protein–protein interactions (PPIs) has not been fully explored. This study aims to develop an improved computational method for driver identification, validation and evaluation (DRIVE), which is compared to other methods for assessing its performance. DRIVE aims at distinguishing between driver and passenger mutations using a feature-based learning approach comprising two levels of biological classification for a pan-cancer assessment of somatic mutations. Gene-level features include the maximum number of protein–protein interactions, the biological process and the type of post-translational modifications (PTMs) while mutation-level features are based on pathogenicity scores. Multiple supervised classification algorithms were trained on Genomics Evidence Neoplasia Information Exchange (GENIE) project data and then tested on an independent dataset from The Cancer Genome Atlas (TCGA) study. Finally, the most powerful classifier using DRIVE was evaluated on a benchmark dataset, which showed a better overall performance compared to other state-of-the-art methodologies, however, considerable care must be taken due to the reduced size of the dataset. DRIVE outlines the outstanding potential that multiple levels of a feature-based learning model will play in the future of oncology-based precision medicine.
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Emlaw, Johnathon R., Christian J. G. Tessier, Gregory D. McCluskey, Melissa S. McNulty, Yusuf Sheikh, Kelly M. Burkett, Maria Musgaard und Corrie J. B. daCosta. „A single historical substitution drives an increase in acetylcholine receptor complexity“. Proceedings of the National Academy of Sciences 118, Nr. 7 (12.02.2021): e2018731118. http://dx.doi.org/10.1073/pnas.2018731118.
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Human adult muscle-type acetylcholine receptors are heteropentameric ion channels formed from four different, but evolutionarily related, subunits. These subunits assemble with a precise stoichiometry and arrangement such that two chemically distinct agonist-binding sites are formed between specific subunit pairs. How this subunit complexity evolved and became entrenched is unclear. Here we show that a single historical amino acid substitution is able to constrain the subunit stoichiometry of functional acetylcholine receptors. Using a combination of ancestral sequence reconstruction, single-channel electrophysiology, and concatenated subunits, we reveal that an ancestral β-subunit can not only replace the extant β-subunit but can also supplant the neighboring δ-subunit. By forward evolving the ancestral β-subunit with a single amino acid substitution, we restore the requirement for a δ-subunit for functional channels. These findings reveal that a single historical substitution necessitates an increase in acetylcholine receptor complexity and, more generally, that simple stepwise mutations can drive subunit entrenchment in this model heteromeric protein.
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Hoekstra, David Arthur, Louise M. Carlson und Kelvin P. Lee. „Rewiring of the Protein Kinase C Beta 2 (PKC βII) and Bcr/Abl Signal Transduction Pathways“. Blood 118, Nr. 21 (18.11.2011): 1673. http://dx.doi.org/10.1182/blood.v118.21.1673.1673.
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Abstract Abstract 1673 Chronic myeloid leukemia (CML) accounts for 20% of adult leukemias, and is characterized by the presence of the bcr-abl fusion gene. This gene leads to the production of a constitutively active Abl tyrosine kinase, which promiscuously phosphorylates/activates a variety of intracellular signal transduction pathways. The presence of constitutively active Abl is essential for CML blast survival even in advanced disease, and underlies the success that the Bcr/Abl kinase inhibitor imatinib has had. However, resistance to imatinib occurs in a significant number of accelerated phase or blast crisis patients and is a significant clinical obstacle. Instead of trying to inhibit Bcr/Abl signaling, we propose a previously unexplored approach to ‘rewire’ kinase signaling pathways to activate a “suicide” prodrug that would not normally be activated by Bcr/Abl. We have previously shown that direct activation of PKCβII by Phorbol 12-myristate 13-acetate (PMA) drives dendritic cell differentiation in both normal and leukemic progenitors, as well as induces apoptosis and growth arrest. PKCβII is a member of the PKC family of serine/threonine kinases and is kept in an inactive state in the cytosol by interactions between its pseudosubstrate and kinase domains; upon activation, the pseudosubstrate domain releases the kinase domain, and PKCβII translocates to the plasma membrane. Substitution of an alanine at position 25 in the pseudosubstrate domain for a phosphomimetic glutamic acid leads to the constitutive activation of PKCβII. Similarly, we hypothesized that substituting the alanine at position 25 for a phosphorylatable tyrosine (A25Y) along with the corresponding Bcr/Abl kinase target motif (Ala-X-X-Ile-Tyr-X-X-Phe/Pro) into the pseudosubstrate domain of PKCβII, would allow the Bcr/Abl tyrosine kinase to activate the PKCβII signaling pathway. Bcr/Abl mediated activation of PKCβII would then lead to the induction of apoptosis, growth inhibition, and differentiation. Using confocal microscopy, we show that following transfection WT-PKCβII is cytoplasmically located in media alone and addition of PMA leads to translocation to the plasma membrane, indicating activation in both Bcr/Abl+ K562 cells, and Bcr/Abl− KG1a cells. However when A25Y-PKCβII constructs are transfected in, A25Y-PKCβII is found at the plasma membrane in K562, but not in KG1a cells in media alone. These observations were then quantified using ImageStream technology, which allows for simultaneous acquisition of both flow cytometric data, and high resolution fluorescent images. Using this technology, we show that A25Y-PKCβII is activated in media alone in K562 cells, and only upon addition of PMA in KG1a cells. Additionally, when Bcr/Abl was stably transfected in KG1a cells, A25Y-PKCβII was able to translocate to the plasma membrane in media alone, indicating activation by Bcr/Abl. Upon activation and translocation to the plasma membrane, PKCβII is rapidly degraded; accordingly, we show that expression of WT PKCβII decreases only by 20% over 72 hours post transfection, whereas expression of A25Y-PKCβII results in an average decrease of 90% over the same 72 hour time course. To test whether activation of A25Y-PKCβII leads to apoptosis and growth arrest, Bcr/Abl+ K562, and Bcr/Abl− KG1a cells were transfected with either WT and A25Y-PKCβII and measured for apoptosis with AnnexinV using Flow Cytometry. We found that A25Y-PKCβII induced a maximum of a 4-fold increase of apoptosis when compared to WT PKCβII in K562 cells; however there was no increase observed in KG1a cells. This work demonstrates that rewiring PKCβII to be inducible by Bcr/Abl is feasible, and that activation of PKCβII by Bcr/Abl induces characteristic translocation to the plasma membrane, and induction of apoptosis. Future work will address whether induction of DC differentiation is maintained in Bcr/Abl activated PKCβII cells, as well as the molecular kinetics of this activation. Disclosures: No relevant conflicts of interest to declare.
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Semykina, Irina, und Alexandra Tarnetskaya. „The Design of Control System for Gearless Synchronous Drum-Motor of the Underground Mine Belt Conveyor“. E3S Web of Conferences 105 (2019): 03004. http://dx.doi.org/10.1051/e3sconf/201910503004.
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Regarding the current tendency of replacing the geared electric drives with gearless drum motor and substitution of the obsolete induction motors with energy-efficient synchronous motors, the authors consider the difficulties of the high-power permanent magnet synchronous motor and present its model with parameters corresponding to the real belt conveyor electric drive parameters. This paper describes the questions of the vector control system simulation for the synchronous gearless drum-motor of an underground belt conveyor. The control of permanent magnet synchronous motor is realized having regard to rotor angle and random traffic flow. The mechanical system of an underground belt conveyor is represented by the multimass system with the viscoelastic bar. As a conclusion, the article presents the results of the direct torque control system simulation in the speed adjustment mode.
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Burskaia, Valentina, Sergey Naumenko, Mikhail Schelkunov, Daria Bedulina, Tatyana Neretina, Alexey Kondrashov, Lev Yampolsky und Georgii A. Bazykin. „Excessive Parallelism in Protein Evolution of Lake Baikal Amphipod Species Flock“. Genome Biology and Evolution 12, Nr. 9 (11.07.2020): 1493–503. http://dx.doi.org/10.1093/gbe/evaa138.
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Abstract Repeated emergence of similar adaptations is often explained by parallel evolution of underlying genes. However, evidence of parallel evolution at amino acid level is limited. When the analyzed species are highly divergent, this can be due to epistatic interactions underlying the dynamic nature of the amino acid preferences: The same amino acid substitution may have different phenotypic effects on different genetic backgrounds. Distantly related species also often inhabit radically different environments, which makes the emergence of parallel adaptations less likely. Here, we hypothesize that parallel molecular adaptations are more prevalent between closely related species. We analyze the rate of parallel evolution in genome-size sets of orthologous genes in three groups of species with widely ranging levels of divergence: 46 species of the relatively recent lake Baikal amphipod radiation, a species flock of very closely related cichlids, and a set of significantly more divergent vertebrates. Strikingly, in genes of amphipods, the rate of parallel substitutions at nonsynonymous sites exceeded that at synonymous sites, suggesting rampant selection driving parallel adaptation. At sites of parallel substitutions, the intraspecies polymorphism is low, suggesting that parallelism has been driven by positive selection and is therefore adaptive. By contrast, in cichlids, the rate of nonsynonymous parallel evolution was similar to that at synonymous sites, whereas in vertebrates, this rate was lower than that at synonymous sites, indicating that in these groups of species, parallel substitutions are mainly fixed by drift.
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Rosa, P. F. S., J. Kang, Yongkang Luo, N. Wakeham, E. D. Bauer, F. Ronning, Z. Fisk, R. M. Fernandes und J. D. Thompson. „Competing magnetic orders in the superconducting state of heavy-fermion CeRhIn5“. Proceedings of the National Academy of Sciences 114, Nr. 21 (09.05.2017): 5384–88. http://dx.doi.org/10.1073/pnas.1703016114.
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Applied pressure drives the heavy-fermion antiferromagnet CeRhIn5 toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that 5% magnetic substitution at the Ce site in CeRhIn5, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of Ce0.95Nd0.05CoIn5. Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.
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Dvorkin, Jack. „Diagenesis-driven pore fluid discrimination“. Leading Edge 38, Nr. 5 (Mai 2019): 366–73. http://dx.doi.org/10.1190/tle38050366.1.
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In order to determine a direct hydrocarbon indicator in an oil field formed by low- to medium-porosity fast sandstone, we examine wireline data from four wells. Fluid substitution indicates that the sensitivity of the acoustic impedance and Poisson's ratio to oil-to-brine changes is very small. It appears, however, that due to diagenetic processes, the porosity in the brine-filled strata is noticeably smaller than that in the oil-saturated intervals. This porosity difference makes the impedance in the presence of oil noticeably smaller than that where brine is present. The respective impedance cutoff can serve as a discriminator for fluid detection in the seismically derived acoustic impedance volumes. The lesson learned is that merely relying on a rock-physics tool, such as fluid substitution, may not necessarily provide a fluid-detection recipe. Instead, we need to examine a plethora of natural events that may affect rock properties and then translate these effects into seismically detectable variables.
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Zeppetella, Luca, Elisa Gebennini, Andrea Grassi und Bianca Rimini. „Optimal production scheduling with customer-driven demand substitution“. International Journal of Production Research 55, Nr. 6 (23.08.2016): 1692–706. http://dx.doi.org/10.1080/00207543.2016.1223895.
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Yücel, Eda, Fikri Karaesmen, F. Sibel Salman und Metin Türkay. „Optimizing product assortment under customer-driven demand substitution“. European Journal of Operational Research 199, Nr. 3 (Dezember 2009): 759–68. http://dx.doi.org/10.1016/j.ejor.2008.08.004.
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Yakushi, Toshiharu, Shingo Maki und Michio Homma. „Interaction of PomB with the Third Transmembrane Segment of PomA in the Na+-Driven Polar Flagellum of Vibrio alginolyticus“. Journal of Bacteriology 186, Nr. 16 (15.08.2004): 5281–91. http://dx.doi.org/10.1128/jb.186.16.5281-5291.2004.
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ABSTRACT The marine bacterium Vibrio alginolyticus has four motor components, PomA, PomB, MotX, and MotY, responsible for its Na+-driven flagellar rotation. PomA and PomB are integral inner membrane proteins having four and one transmembrane segments (TMs), respectively, which are thought to form an ion channel complex. First, site-directed Cys mutagenesis was systematically performed from Asp-24 to Glu-41 of PomB, and the resulting mutant proteins were examined for susceptibility to a sulfhydryl reagent. Secondly, the Cys substitutions at the periplasmic boundaries of the PomB TM (Ser-38) and PomA TMs (Gly-23, Ser-34, Asp-170, and Ala-178) were combined. Cross-linked products were detected for the combination of PomB-S38C and PomA-D170C mutant proteins. The Cys substitutions in the periplasmic boundaries of PomA TM3 (from Met-169 to Asp-171) and the PomB TM (from Leu-37 to Ser-40) were combined to construct a series of double mutants. Most double mutations reduced the motility, whereas each single Cys substitution slightly affected it. Although the motility of the strain carrying PomA-D170C and PomB-S38C was significantly inhibited, it was recovered by reducing reagent. The strain with this combination showed a lower affinity for Na+ than the wild-type combination. PomA-D148C and PomB-P16C, which are located at the cytoplasmic boundaries of PomA TM3 and the PomB TM, also formed the cross-linked product. From these lines of evidence, we infer that TM3 of PomA and the TM of PomB are in close proximity over their entire length and that cooperation between these two TMs is required for coupling of Na+ conduction to flagellar rotation.
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Dmitrievskii, Vladimir, Vladimir Prakht und Vadim Kazakbaev. „Design Optimization of a Permanent-Magnet Flux-Switching Generator for Direct-Drive Wind Turbines“. Energies 12, Nr. 19 (24.09.2019): 3636. http://dx.doi.org/10.3390/en12193636.
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Due to the increasing need for direct-drive wind turbines, a large number of papers are dedicated to the optimization of low-speed wind generators. A permanent-magnet flux-switching machine can be a valuable option to use in such applications. This paper describes the optimization procedure of a direct-drive flux-switching wind generator. The average losses, the required converter power, and the cost of permanents magnets were chosen as the optimization objectives. To reduce the calculation efforts during the optimization, a method to construct the substituting load profiles is proposed. Two-mode and three-mode substituting profiles were constructed on the basis of the nine-mode initial profile. The losses calculated under the two-mode, three-mode, and nine-mode profiles accurately coincided, which supported the use of the low-mode substituting profiles instead of the initial one. During the optimization, the average losses decreased by 30%, which corresponded to an increase in the average efficiency by almost 6%. The required converter power was decreased by 10%. The total active material mass, cogging torque, and torque ripple were also slightly decreased.
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Gaymard, Sandrine, und Jean-Claude Etoundi. „Admit One’s Driving Offences or Attribute Them to Others: An Exploratory Study Among a Sample of Cameroonian Drivers“. Mediterranean Journal of Social Sciences 9, Nr. 4 (01.07.2018): 157–65. http://dx.doi.org/10.2478/mjss-2018-0125.
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Abstract In the field of social thinking the question of norms give rise to several publications. Moreover there exists no study in this theoretical framework concerning Cameroon drivers’ relationship with the rule. In order to understand this, a group of 50 motorists filled out a characterization questionnaire on driving, purposely oriented to the use of the mobile. The instructions to the drivers were to fill it out for themselves (standard condition) and for other drivers (substitution condition). The results confirm the role of the substitution instructions in bringing to light inadmissible offences with standard instructions. It can be concluded that the Cameroon drivers are well aware of the rule and that they tend to attribute the greatest transgressions to other drivers.
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Buckler, Edward S., Anthony Ippolito und Timothy P. Holtsford. „The Evolution of Ribosomal DNA Divergent Paralogues and Phylogenetic Implications“. Genetics 145, Nr. 3 (01.03.1997): 821–32. http://dx.doi.org/10.1093/genetics/145.3.821.
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Although nuclear ribosomal DNA (rDNA) repeats evolve together through concerted evolution, some genomes contain a considerable diversity of paralogous rDNA. This diversity includes not only multiple functional loci but also putative pseudogenes and recombinants. We examined the occurrence of divergent paralogues and recombinants in Gossypium, Nicotiana, Tripsacum, Winteraceae, and Zea ribosomal internal transcribed spacer (ITS) sequences. Some of the divergent paralogues are probably rDNA pseudogenes, since they have low predicted secondary structure stability, high substitution rates, and many deamination-driven substitutions at methylation sites. Under standard PCR conditions, the low stability paralogues amplified well, while many high-stability paralogues amplified poorly. Under highly denaturing PCR conditions (i.e., with dimethylsulfoxide), both low- and high-stability paralogues amplified well. We also found recombination between divergent paralogues. For phylogenetics, divergent ribosomal paralogues can aid in reconstructing ancestral states and thus serveas good outgroups. Divergent paralogues can also provide companion rDNA phylogenies. However, phylogeneticists must discriminate among families of divergent paralogues and recombinants or suffer from muddled and inaccurate organismal phylogenies.
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Weiß, Clemens L., Verena J. Schuenemann, Jane Devos, Gautam Shirsekar, Ella Reiter, Billie A. Gould, John R. Stinchcombe, Johannes Krause und Hernán A. Burbano. „Temporal patterns of damage and decay kinetics of DNA retrieved from plant herbarium specimens“. Royal Society Open Science 3, Nr. 6 (Juni 2016): 160239. http://dx.doi.org/10.1098/rsos.160239.
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Herbaria archive a record of changes of worldwide plant biodiversity harbouring millions of specimens that contain DNA suitable for genome sequencing. To profit from this resource, it is fundamental to understand in detail the process of DNA degradation in herbarium specimens. We investigated patterns of DNA fragmentation and nucleotide misincorporation by analysing 86 herbarium samples spanning the last 300 years using Illumina shotgun sequencing. We found an exponential decay relationship between DNA fragmentation and time, and estimated a per nucleotide fragmentation rate of 1.66 × 10 −4 per year, which is six times faster than the rate estimated for ancient bones. Additionally, we found that strand breaks occur specially before purines, and that depurination-driven DNA breakage occurs constantly through time and can to a great extent explain decreasing fragment length over time. Similar to what has been found analysing ancient DNA from bones, we found a strong correlation between the deamination-driven accumulation of cytosine to thymine substitutions and time, which reinforces the importance of substitution patterns to authenticate the ancient/historical nature of DNA fragments. Accurate estimations of DNA degradation through time will allow informed decisions about laboratory and computational procedures to take advantage of the vast collection of worldwide herbarium specimens.
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Brzezicki, Wojciech, Filomena Forte, Canio Noce, Mario Cuoco und Andrzej M. Oleś. „Tuning Crystal Field Potential by Orbital Dilution in Strongly Correlated d4 Oxides“. Journal of Superconductivity and Novel Magnetism 33, Nr. 8 (30.12.2019): 2375–81. http://dx.doi.org/10.1007/s10948-019-05386-0.
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AbstractWe investigate the interplay between Coulomb-driven orbital order and octahedral distortions in strongly correlated Mott insulators due to orbital dilution, i.e., doping by metal ions without an orbital degree of freedom. In particular, we focus on layered transition metal oxides and study the effective spin–orbital exchange due to d3 substitution at d4 sites. The structure of the d3 − d4 spin–orbital coupling between the impurity and the host in the presence of octahedral rotations favors a distinct type of orbital polarization pointing towards the impurity and outside the impurity–host plane. This yields an effective lattice potential that generally competes with that associated with flat octahedra and, in turn, can drive an inversion of the crystal field interaction.
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Kumar, Dinesh, und Komal Sethi. „A Key Driven Robust Substitution Technique with Enhanced Capacity“. International Journal of Engineering Trends and Technology 23, Nr. 7 (25.05.2015): 341–45. http://dx.doi.org/10.14445/22315381/ijett-v23p264.
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Bodrikov, I. V., Yu A. Kurskii, A. A. Chiyanov, N. V. Borisova und A. Yu Subbotin. „Sterically driven allyl substitution in alkenes with electrophilic iodine“. Doklady Chemistry 450, Nr. 2 (Juni 2013): 162–64. http://dx.doi.org/10.1134/s0012500813060049.
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Vagadia, Megha, Ashish Ravalia, Savan Katba, P. S. Solanki, Komal Bapna, Manish Kumar, R. J. Choudhary, D. M. Phase und D. G. Kuberkar. „Co-substitution driven electronic structure modifications in Zn1−xCoxO“. Journal of Alloys and Compounds 610 (Oktober 2014): 113–17. http://dx.doi.org/10.1016/j.jallcom.2014.04.213.
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Tabachnikova, T. V., und Y. N. Erashova. „A simulation model of electric actuator unit of electric centrifugal pump with a submersible individual compensation installation“. E3S Web of Conferences 124 (2019): 05071. http://dx.doi.org/10.1051/e3sconf/201912405071.
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The substitution scheme and the system of differential equations for electrotechnical complex of producing well are given. The mathematical and simulation models of electric drive of electric centrifugal pump installation with submersible individual compensating installation are developed. The scheme of inclusion and practical realization of individual compensating installation consisting of the static capacitor battery with non-standard nominal voltage which is connected directly to the stator clips of submersible electric motor in a well is proposed. The simulation model of electric actuator of the electric centrifugal pump allows one to simulate the operation mode of electric actuator in steady-state and transient modes, as well as the group start of electric drives of electrical complex of the producing well. The optimal level of outgoing line voltage, energy parameters and the optimal parameters of individual, node and centralized compensating installations, as well as the rational voltage level of the main substation were determined from simulation.
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Ibeh, Neke, Jean Claude Nshogozabahizi und Stéphane Aris-Brosou. „Both Epistasis and Diversifying Selection Drive the Structural Evolution of the Ebola Virus Glycoprotein Mucin-Like Domain“. Journal of Virology 90, Nr. 11 (23.03.2016): 5475–84. http://dx.doi.org/10.1128/jvi.00322-16.
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ABSTRACTThroughout the last 3 decades, Ebola virus (EBOV) outbreaks have been confined to isolated areas within Central Africa; however, the 2014 variant reached unprecedented transmission and mortality rates. While the outbreak was still under way, it was reported that the variant leading up to this outbreak evolved faster than previous EBOV variants, but evidence for diversifying selection was undetermined. Here, we test this selection hypothesis and show that while previous EBOV outbreaks were preceded by bursts of diversification, evidence for site-specific diversifying selection during the emergence of the 2014 EBOV clade is weak. However, we show strong evidence supporting an interplay between selection and correlated evolution (epistasis), particularly in the mucin-like domain (MLD) of the EBOV glycoprotein. By reconstructing ancestral structures of the MLD, we further propose a structural mechanism explaining how the substitutions that accumulated between 1918 and 1969 distorted the MLD, while more recent epistatic substitutions restored part of the structure, with the most recent substitution being adaptive. We suggest that it is this complex interplay between weak selection, epistasis, and structural constraints that has shaped the evolution of the 2014 EBOV variant.IMPORTANCEThe role that selection plays in the emergence of viral epidemics remains debated, particularly in the context of the 2014 EBOV outbreak. Most critically, should such evidence exist, it is generally unclear how this relates to function and increased virulence. Here, we show that the viral lineage leading up to the 2014 outbreak underwent a complex interplay between selection and correlated evolution (epistasis) in a protein region that is critical for immune evasion. We then reconstructed the three-dimensional structure of this domain and showed that the initial mutations in this lineage deformed the structure, while subsequent mutations restored part of the structure. Along this mutational path, the first and last mutations were adaptive, while the intervening ones were epistatic. Altogether, we provide a mechanistic model that explains how selection and epistasis acted on the structural constraints that materialized during the 2014 EBOV outbreak.