Journal articles on the topic 'A ring with stable range n'
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Yu, Hua-Ping, and Victor P. Camilo. "On strongly pi-regular rings of stable range one." Bulletin of the Australian Mathematical Society 51, no. 3 (June 1995): 433–37. http://dx.doi.org/10.1017/s0004972700014258.
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An associative ring R is said to have stable range one if for any a, b ∈ R satisfying aR + bR = R, there exists y ∈ R such that a + by is right (equivalently, left) invertible. Call a ring R strongly π-regular if for every element a ∈ R there exist a number n (depending on a) and an element x ∈ R such that an = an+1x. It is an open question whether all strongly π-regular rings have stable range one. The purpose of this note is to prove the following Theorem: If R is a strongly π-regular ring with the property that all powers of every nilpotent von Neumann regular element are von Neumann regular in R, then R has stable range one.
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Xiao, Guangshi, and Wenting Tong. "n-Clean Rings and Weakly Unit Stable Range Rings." Communications in Algebra 33, no. 5 (April 2005): 1501–17. http://dx.doi.org/10.1081/agb-200060531.
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Chen, Huanyin, and Fu-an Li. "Exchange Rings Satisfying the n-Stable Range Condition, II." Algebra Colloquium 10, no. 1 (June 2003): 1–8. http://dx.doi.org/10.1007/s100110300000.
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Vaserstein, Leonid N., and Ethel Wheland. "Factorization of invertible matrices over rings of stable rank one." Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics 48, no. 3 (June 1990): 455–60. http://dx.doi.org/10.1017/s1446788700029980.
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AbstractEvery invertible n-by-n matrix over a ring R satisfying the first Bass stable range condition is the product of n simple automorphisms, and there are invertible matrices which cannot be written as the products of a smaller number of simple automorphisms. This generalizes results of Ellers on division rings and local rings.
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SANYAL, BIPLAB, and ABHIJIT MOOKERJEE. "STUDY OF THE ELECTRONIC AND STRUCTURAL PROPERTIES OF ZnO CLUSTERS." International Journal of Modern Physics B 24, no. 17 (July 10, 2010): 3297–309. http://dx.doi.org/10.1142/s0217979210052209.
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We present a systematic first-principle study of the structures, energetics and electronic structure of (ZnO) n clusters in the size range 1 ≤ n≤ 12. We show that the planar ring structures are stable for n < 8, while spheroidal structures made out of rings of (ZnO) 3 and (ZnO) 2 are stable for n ≥ 8. We examine the binding energies and HOMO–LUMO gaps of the clusters and try to understand our results from simple physical ideas.
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Deoghare, Chetana Anand. "Thermally Stable Copolymers with Pendant “N-Arylimide” Groups Via Reversible Deactivation Radical Polymerization Technique." ECS Transactions 107, no. 1 (April 24, 2022): 18175–87. http://dx.doi.org/10.1149/10701.18175ecst.
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This paper reports the synthesis of copolymers of N-arylitaconimides (NAI) and methyl methacrylate (MMA) with random architecture via activator generated electron transfer atom transfer radical polymerization (AGET-ATRP) method, resulting in N-arylimide as pendant group.The AGET-ATRP is a versatile and famous reversible deactivation radical polymerization technique used to synthesize the well defined polymers. The structural characterizations of obtained copolymers were done using FT-IR, 1H-NMR spectroscopy and elemental analysis. The molecular weights of copolymers were in the range 8,000-20,000 g/ mol with a narrow polydispersity index i.e. 1.2-1.3. Thermal characterization of Poly(NAI-ran-MMA) copolymers were done using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG/ DTG). DSC scans show 60-117% enhancements in the glass transition temperature (Tg), as compared to Poly(methyl methacrylate). The rate of copolymerization, molecular weight and Tg were observed to increase with increase in electron releasing nature of the substituent on aromatic ring of the pendant group.
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Arulsamy, Navamoney, D. Scott Bohle, and Inna Perepichka. "Chemistry of the potassium, silver, and tetra(n-butyl)ammonium salts of sydnone N-oxide (Traube's anion)." Canadian Journal of Chemistry 85, no. 2 (February 1, 2007): 105–17. http://dx.doi.org/10.1139/v07-001.
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Traube's dianion, 4-methylcarboxysydnone-3-hydroxylate (2), and its monomethyl ester (1) are readily isolated as their di- and mono-potassium salts from the reaction of nitric oxide with dimethylmalonate and potassium methoxide in methanol. Metathesis reactions of 1 with silver nitrate and tetra(n-butyl)ammonium bromide yield the silver and tetra(n-butyl)ammonium salts of 4-methylcarboxysydnone-3-hydroxylate. In contrast to other known sydnone derivatives, the present sydnones are stable in both acidic and basic solutions. Single crystal X-ray diffraction data obtained for 2 and the silver salt (3) reveal planarity and delocalization of double bonds in the sydnone ring, indicating aromatic behavior. The tetra(n-butyl)ammonium salt (4) is soluble in a range of organic compounds. Cyclic voltammetric data measured for 4 in acetonitrile reveal an irreversible oxidation peak at +1.09 V vs. Fc–Fc+ couple suggesting that the sydnone derivatives can be oxidized with an appropriate oxidizing agent. Differential scanning calorimetry data reveal thermal stability at ambient conditions and exothermic decomposition at high temperatures (>229 °C). The sydnone derivatives are characterized by two strong electronic absorptions in the UV region and rich vibrational (IR and Raman) spectra in the 1800–1500 cm–1 region. Density functional theory (B3LYP/6-311+++G**) is applied to estimate the aromaticity of the sydnone ring and to assign the vibrational spectral data.Key words: sydnone, trans-diazeniumdiolate, N-oxide.
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Seino, Hiroshi, Osamu Haba, Amane Mochizuki, Masahiro Yoshioka, and Mitsuru Ueda. "Preparation and Properties of Polyisoimides as a Highly Dimensionally Stable Polyimide Precursor with Low Dielectric Constant." High Performance Polymers 9, no. 3 (September 1997): 333–44. http://dx.doi.org/10.1088/0954-0083/9/3/011.
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Fluorinated polyimides (PIs) with low dielectric constant and high dimensional stability have been developed using polyisoimides (PIIs) as a polyimide precursor. The PIIs were prepared by the ring-opening polyaddition of the dianhydrides pyromellitic dianhydride, biphenyltetracarboxylic dianhydride and 4, 4′-hexafluoropropylidenedi(phthalic anhydride) with the diamines 2, 2′-dimethylbenzidine and 2, 2′-bis(trifluoromethyl)benzidine, followed by treatment with trifluoroacetic anhydride/triethylamine or dicyclohexylcarbodiimide in N;N-dimethylacetamide. The PIIs were soluble in a wide range of solvents including dipolar aprotic solvents, cyclohexanone and tetrahydrofuran at room temperature, and easy to convert to corresponding PIs by high thermal treatment. The resulting PIs showed low dielectric constants of less than 3 at 1 MHz as well as low CTEs. Furthermore, during the isomerization reaction, migration of copper in the PI film was hardly observed.
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YAMAPI, R., and M. A. AZIZ-ALAOUI. "STABILITY OF THE CONTROLLED SYNCHRONIZATION MANIFOLD IN A RING OF MUTUALLY COUPLED CHAOTIC SYSTEMS." International Journal of Bifurcation and Chaos 18, no. 08 (August 2008): 2397–414. http://dx.doi.org/10.1142/s0218127408021774.
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The active control of the unstable synchronization manifold in a shift-invariant ring of N mutually coupled chaotic oscillators is investigated. After deriving the bifurcation structures and chaotic states in the single oscillator, we find the regime of coupling parameters leading to stable and unstable synchronization phenomena in the ring, using the Master stability function approach with the transverse Lyapunov exponents. The active control technique is applied on the mutually coupled chaotic systems to suppress unstable synchronization states. We derive the range of control gain parameters which leads to a successful control and the stability of the control design. The effects of the amplitude of the parametric perturbations on the stability boundaries of the controlled unstable synchronization process are also studied.
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Vuckovic, Gordana, Sladjana Tanaskovic, Mirjana Antonijevic-Nikolic, Vukosava Zivkovic-Radovanovic, and Gordana Gojgic-Cvijovic. "A study of novel cobalt(II) octaazamacrocyclic complexes with aminocarboxylates or their derivatives." Journal of the Serbian Chemical Society 74, no. 6 (2009): 629–40. http://dx.doi.org/10.2298/jsc0906629v.
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Four new air-stable mixed-ligand Co(II) complexes having the general formula [Co2(Y)tpmc]Z3?q(H2O/CH3CN) (HY = N-methylglycine/N,N-dimethylglycine, Z = - 4BF , qH2O=4 or 3; HY=S-norvaline/S-valine Z=-ClO4 , qCH3CN = 0.5; qH2O = 0.5; tpmc = N,N',N'',N'''-tetrakis(2-pyridylmethyl)- -1,4,8,11-tetraazacyclotetradecane) were prepared. The composition, some physical and chemical properties and their tentative geometries were evaluated based on elemental analysis (C, H, N), conductometric and magnetic measurements, spectroscopic data (UV/Vis, IR) and cyclic voltammetry. The data were compared with earlier described analogous complexes containing the macrocyclic ligand and aliphatic aminocarboxylates. It is assumed that all complexes are binuclear with an exo coordination mode of the octaazamacrocyclic pendant ligand in the boat conformation. In addition, two -N-(CH2)2-N- portions of the cyclam ring within the tpmc ligand and Co(II) ions in the high-spin state are most probably bridged via oxygen atoms from the anion of the aminocarboxylate/derivatives, whereas nitrogen atoms rest uncoordinated. In all cases, a combined chelate-bridged coordination is proposed as the most probable. The complexes were electrochemically stable in the potential range -1.0 to 1.0 V. They were also preliminary assayed toward some microorganisms together with the ligands, starting simple salts and solvents as test substances. In some cases, certain antimicrobial activity of the complexes was detected.
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Plotnikova, E. A., M. A. Grin, P. V. Ostroverkhov, I. V. Pantushenko, R. I. Yakubovskaya, and A. D. Kaprin. "Primary screening of substances-photosensibilizers of the bacteriochlorin range for photodynamic therapy of malignant neoplasms." Biomeditsinskaya Khimiya 64, no. 3 (2018): 283–89. http://dx.doi.org/10.18097/pbmc20186403283.
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This paper presents a primary screening of bacteriochlorin-type compounds with aminoamide, propyl and carbohydrate substituents aimed for development a new generation photosensitizers (PS) for photodynamic therapy of malignant tumors. Absorption and fluorescence spectral characteristics of the compounds, their storage stability in solutions under dark conditions and light exposure, photo-induced and dark cytotoxicity against human HEp2 tumor cells have been studied. It has been shown that the dyes with aminoamide substituents have an absorbtion maximum at 754±2 nm in the long wavelength region and they are not stable during storage (the specific fluorescence intensity decreased by 33-56% during 24 hours). The long wavelength region absorption of the propyl and carbohydrate substituted compounds varied in the range 780-831 nm, they were stable in solutions during storage and under light irradiation. Except the dye with a carbohydrate residue in the exocycle E, all PS exhibited the high photo-induced activity and low level of the dark cytotoxicity. The highest photo-induced cytotoxicity was observed for compounds with aminoamide substituents inthe macrocyclic ring (IC 50 values ranged from 17 nM to49 nM after 2 hour incubation with PS followed by exposure to the 10 J/cm 2 dose of red light). Taking into account the totality of the physico-chemical and biological properties, as well as manufacturability of production, O-propyloxime-N-propoxybacteriopurinimide methyl ester was chosen as the most promising candidate compound for further investigations.
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Yates, Edwin A., Bodo Philipp, Catherine Buckley, Steve Atkinson, Siri Ram Chhabra, R. Elizabeth Sockett, Morris Goldner, et al. "N-Acylhomoserine Lactones Undergo Lactonolysis in a pH-, Temperature-, and Acyl Chain Length-Dependent Manner during Growth of Yersinia pseudotuberculosis and Pseudomonas aeruginosa." Infection and Immunity 70, no. 10 (October 2002): 5635–46. http://dx.doi.org/10.1128/iai.70.10.5635-5646.2002.
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ABSTRACT In gram-negative bacterial pathogens, such as Pseudomonas aeruginosa and Yersinia pseudotuberculosis, cell-to-cell communication via the N-acylhomoserine lactone (AHL) signal molecules is involved in the cell population density-dependent control of genes associated with virulence. This phenomenon, termed quorum sensing, relies upon the accumulation of AHLs to a threshold concentration at which target structural genes are activated. By using biosensors capable of detecting a range of AHLs we observed that, in cultures of Y. pseudotuberculosis and P. aeruginosa, AHLs accumulate during the exponential phase but largely disappear during the stationary phase. When added to late-stationary-phase, cell-free culture supernatants of the respective pathogen, the major P. aeruginosa [N-butanoylhomoserine lactone (C4-HSL) and N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL)] and Y. pseudotuberculosis [N-(3-oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL)] AHLs were inactivated. Short-acyl-chain compounds (e.g., C4-HSL) were turned over more extensively than long-chain molecules (e.g., 3-oxo-C12-HSL). Little AHL inactivation occurred with cell extracts, and no evidence for inactivation by specific enzymes was apparent. This AHL turnover was discovered to be due to pH-dependent lactonolysis. By acidifying the growth media to pH 2.0, lactonolysis could be reversed. By using carbon-13 nuclear magnetic resonance spectroscopy, we found that the ring opening of homoserine lactone (HSL), N-propionyl HSL (C3-HSL), and C4-HSL increased as pH increased but diminished as the N-acyl chain was lengthened. At low pH levels, the lactone rings closed but not via a simple reversal of the ring opening reaction mechanism. Ring opening of C4-HSL, C6-HSL, 3-oxo-C6-HSL, and N-octanoylhomoserine lactone (C8-HSL), as determined by the reduction of pH in aqueous solutions with time, was also less rapid for AHLs with more electron-donating longer side chains. Raising the temperature from 22 to 37°C increased the rate of ring opening. Taken together, these data show that (i) to be functional under physiological conditions in mammalian tissue fluids, AHLs require an N-acyl side chain of at least four carbons in length and (ii) that the longer the acyl side chain the more stable the AHL signal molecule.
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Hargan, Kathryn E., Emily M. Stewart, Neal Michelutti, Christopher Grooms, Linda E. Kimpe, Mark L. Mallory, John P. Smol, and Jules M. Blais. "Sterols and stanols as novel tracers of waterbird population dynamics in freshwater ponds." Proceedings of the Royal Society B: Biological Sciences 285, no. 1877 (April 25, 2018): 20180631. http://dx.doi.org/10.1098/rspb.2018.0631.
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With the expansion of urban centres in the mid-twentieth century and the post-1970 decrease in pesticides, populations of double-crested cormorants ( Phalacrocorax auritus ) and ring-billed gulls ( Larus delawarensis ) around Lake Ontario (Canada and USA) have rapidly rebounded, possibly to unprecedented numbers. Along with the use of traditional palaeolimnological methods (e.g. stable isotopes, biological proxies), we now have the capacity to develop specific markers for directly tracking the presence of waterbirds on nesting islands. Here, we apply the use of lipophilic sterols and stanols from both plant and animal-faecal origins as a reliable technique, independent of traditional isotopic methods, for pinpointing waterbird arrival and population growth over decadal timescales. Sterol and stanol concentrations measured in the guano samples of waterbird species were highly variable within a species and between the three species of waterbirds examined. However, cholesterol was the dominant sterol in guano, and phytosterols were also high in ring-billed gull guano. This variability highlights a specialist piscivorous diet for cormorants compared to a generalist, omnivorous diet for gulls, which may now often include grain and invertebrates from agricultural fields. A ratio that includes cholesterol and sitosterol plus their aerobically reduced products (cholestanol, stigmastanol) best explained the present range of bird abundance across the islands and was significantly correlated to sedimentary δ 15 N. Overall, we demonstrate the use of sterols and stanols as a direct means for tracking the spatial and temporal presence of waterbirds on islands across Lake Ontario, and probably elsewhere.
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Pan, Like, Jianmin Han, Zhiyong Yang, Jialin Wang, Xiang Li, Zhiqiang Li, and Weijing Li. "Temperature Effects on the Friction and Wear Behaviors of SiCp/A356 Composite against Semimetallic Materials." Advances in Materials Science and Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/1824080.
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Due to the low density and high temperature resistance, the SiCp/A356 composites have great potential for weight reduction and braking performance using the brake disc used in trains and automobiles. But the friction coefficient and braking performance are not stable in the braking process because of temperature rising. In this paper, friction and wear behaviors of SiCp/A356 composite against semimetallic materials were investigated in a ring-on-disc configuration in the temperature range of 30°C to 300°C. Experiments were conducted at a constant sliding speed of 1.4 m/s and an applied load of 200 N. Worn surface, subsurface, and wear debris were also examined by using SEM and EDS techniques. The third body films (TBFs) lubricated wear transferred to the third body abrasive wear above 200°C, which was a transition temperature. The friction coefficient decreased and weight of semimetallic materials increased with the increase of temperature and the temperature had almost no effect on the weight loss of composites. The dominant wear mechanism of the composites was microploughing and slight adhesion below 200°C, while being controlled by cutting grooves, severe adhesion, and delamination above the 200°C.
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Reimchen, T. E., S. McGehee, and B. W. Glickman. "Tree ring growth and stable isotopes as potential indicators of historical seabird activities on forested islands in coastal British Columbia." Canadian Field-Naturalist 127, no. 2 (October 24, 2013): 146. http://dx.doi.org/10.22621/cfn.v127i2.1445.
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We examined yearly rings from increment cores of conifers on two seabird nesting islands (one in the Lucy Islands and one in the Rankine Islands, British Columbia), to determine whether trees contained signatures of historical activity of seabirds. Ten conifers (primarily Sitka Spruce, Picea sitchensis), ranging from 56 cm to 127 cm diameter (average 90 cm) and ranging from 70 to 232 years in age (average 132 years of age), were cored across a 200-m gradient in densities of seabird burrows. At the site in the lucy Islands, annual growth was highest (8–14 mm) in the trees with the highest seabird burrow densities and highest in the earliest rings (~1930), which were followed by a fluctuating reduction down to ~2 mm/year in the year 2000, but with a secondary elevated growth period in the 1970s. Adjacent control trees without seabird burrows had a growth rate of ~2 mm/year throughout the same period. At the site in the Rankine Islands, growth rates were also variable and exhibited a 10–15 year non-synchronous periodicity, with the highest growths in the location with high seabird burrow density. Nitrogen isotope signatures (δ15N), which are greatly elevated in seabird guano, ranged from minus 3.9% to 17.4% among tree rings (n = 245 rings) and were positively correlated to percentage nitrogen in rings, average ring growth, and burrow densities. Using these methods, we infer from our tree ring data that seabird activity declined on the lucy Islands over a 70-year period and that the combination of growth, nitrogen isotopic signatures, and percentage nitrogen in tree rings as well a more detailed sampling grid of target and adjacent control trees will provide seabird biologists with additional tools for evaluating spatial and historical trends in seabird activity on forested islands.
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Schaefer, Ted, Jeremy P. Kunkel, Robert W. Schurko, and Guy M. Bernard. "A precise analysis of the 1H nuclear magnetic resonance spectrum of 2-phenyl-1,3-dithiane. Ring pucker, signs of long-range J(H,H), internal rotational barrier, and van der Waals shifts." Canadian Journal of Chemistry 72, no. 7 (July 1, 1994): 1722–27. http://dx.doi.org/10.1139/v94-217.
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The 1H nuclear magnetic resonance spectrum of 2-phenyl-1,3-dithiane, as a dilute solution in a CS2–C6D12–TMS solvent mixture at 300 K, is analyzed to yield 8 chemical shifts and 22 distinct coupling constants, nJ(H,H), n = 2–6. The coupling constant between H-2 and the para proton indicates, first, that the bisected conformer (phenyl plane perpendicular to the pseudo plane of the dithiane ring) is most stable and, second, that the apparent twofold barrier to rotation about the Csp2—Csp3 bond is 9.6 kJ/mol. The AM1, STO-3G, and STO-3G* computations confirm the twofoldedness of the barrier; the AM1 barrier is 9.4 kJ/mol. The empirical equation, [Formula: see text] reproduces the vicinal coupling constants of the CH2CH2CH2 fragments and implies puckering angles [Formula: see text] of 54°, 61°, and 64°, respectively. It is implied that 3J at [Formula: see text] is larger than at [Formula: see text] This results is discussed in terms of the latest theoretical approach to 3J in the HCCH fragment. The 4J(H,H) signs and magnitudes for the CH2CH2CH2 fragment agree reasonably well with theory. For the CH2SCH fragment, 4J(H,H) values are positive, in contrast to corresponding numbers in the propanic fragment, perhaps the first experimental values for certain rigid orientations about a heteroatom. INDO MO FPT computations on propane, dimethyl ether, and dimethyl sulfide confirm the experimental trend in 4J(H,H). 2J(H,H) and 5J(H,H) values are compared to those in related molecules. The striking differential shifts of the axial and equatorial protons are attributed to differential van der Waals interactions with the 3p lone-pair orbital on sulfur. A comparison of the ring proton chemical shifts with those in phenylcyclohexane and isopropylbenzene implies that C—S bonds are weaker net electron donors by hyperconjugation than are C—C bonds. It is also proposed that the ortho protons are deshielded by intramolecular van der Waals interactions with the 3p orbitals on the sulfur atoms.
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Corporaal, A., J. Kluska, H. Van Winckel, D. Bollen, D. Kamath, and M. Min. "Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc." Astronomy & Astrophysics 650 (June 2021): L13. http://dx.doi.org/10.1051/0004-6361/202141154.
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Context. The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system, IRAS 08544−4431. Aims. We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544−4431. The aim is to constrain different contributions to the total flux in the H-, K-, L-, and N-bands in the radial direction. Methods. The data obtained with the three current instruments on the Very Large Telescope Interferometer (VLTI), VLTI/PIONIER, VLTI/GRAVITY, and VLTI/MATISSE, range from the near-infrared, where the post-AGB star dominates, to the mid-infrared, where the disc dominates. We fitted the following two geometric models to the visibility data to reproduce the circumbinary disc: a ring with a Gaussian width and a flat disc model with a temperature gradient. The flux contributions from the disc, the primary star (modelled as a point source), and an over-resolved component were recovered along with the radial size of the emission, the temperature of the disc as a function of radius, and the spectral dependencies of the different components. Results. The trends of all visibility data were well reproduced with the geometric models. The near-infrared data were best fitted with a Gaussian ring model, while the mid-infrared data favoured a temperature gradient model. This implies that a vertical structure is present at the disc inner rim, which we attribute to a rounded puffed-up inner rim. The N-to-K size ratio is 2.8, referring to a continuous flat source, analogues to young stellar objects. Conclusions. By combining optical interferometric instruments operating at different wavelengths, we can resolve the complex structure of circumstellar discs and study the wavelength-dependent opacity profile. A detailed radial, vertical, and azimuthal structural analysis awaits a radiative transfer treatment in 3D to capture all non-radial complexity.
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Jumbri, Khairulazhar, Mohd Azlan Kassim, Normawati M. Yunus, Mohd Basyaruddin Abdul Rahman, Haslina Ahmad, and Roswanira Abdul Wahab. "Fluorescence and Molecular Simulation Studies on the Interaction between Imidazolium-Based Ionic Liquids and Calf Thymus DNA." Processes 8, no. 1 (December 20, 2019): 13. http://dx.doi.org/10.3390/pr8010013.
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This work presents a molecular level investigation on the nature and mode of binding between imidazolium-based ionic liquids (ILs) ([Cnbim]Br where n = 2, 4, 6) with calf thymus DNA. This investigation offers valuable insight into the mechanisms of interactions that can affect the structural features of DNA and possibly cause the alteration or inhibition of DNA function. To expedite analysis, the study resorted to using molecular docking and COnductor like Screening MOdel for Real Solvents (COSMO-RS) in conjunction with fluorescence spectroscopic data for confirmation and validation of computational results. Both the fluorescence and docking studies consistently revealed a weak interaction between the two molecules, which corresponded to the binding energy of a stable docking conformation in the range of −5.19 to −7.75 kcal mol−1. As predicted, the rod-like structure of imidazolium-based ILs prefers to bind to the double-helix DNA through a minor groove. Interestingly, the occurrence of T-shape π-π stacking was observed between the amine group in adenine that faces the aromatic ring of imidazole. In addition, data of COSMO-RS for the interaction of individual nucleic acid bases to imidazolium-based ILs affirmed that ILs showed a propensity to bind to different bases, the highest being guanine followed by cytosine, thymine, uracil, and adenine.
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Buchko, Garry W., Frank E. Hruska, and Krishan L. Sadana. "Synthesis and properties of DNA oligomers containing an O4-ethylated thymine. d(e4TpA), d(Ape4T), d(Ape4TpA), and d(Tpe4TpT)." Canadian Journal of Chemistry 68, no. 11 (November 1, 1990): 2011–21. http://dx.doi.org/10.1139/v90-308.
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Syntheses via the phosphotriester method are described for DNA oligonucleotides containing O4-ethylated thymine (e4Thy) and adenine (Ade) bases, d(e4TpA), d(Ape4T), and d(Ape4TpA), for their unmodified analogs, d(TpA), d(ApT), and d(ApTpA), and for d(Tpe4TpT). 1H NMR chemical shift data obtained from 10 to 70 °C at 300 and 500 MHz show that these molecules form right-handed minihelices at low temperature in aqueous solution; the presence of the O4-ethyl group does not seem to have a drastic effect on the stacking geometry of the thymine base. The presence of right-handed stacking is confirmed by circular dichroic data obtained over a similar temperature range. Coupling constants for the sugar ring indicate that the e4Tp unit of d(e4TpA) does not show the shift towards the 3′-endo (N) pucker noted for the corresponding unit of d(e4TpT). A prominent quasimolecular ion peak [M – H]− is observed for the modified and unmodified molecules in the spectra obtained by Fast Atom Bombardment mass spectrometry (FAB-MS) operating in the negative ion mode, indicating that the labile O4-ethyl group is sufficiently stable to withstand the ionization process used in this method. In addition, a number of fragment ion peaks such as [O4-ethylthymine – H]− are observed that reveal the potential of FAB-MS for characterizing DNA oligomers modified by alkylating agents. Keywords: oligonucleotides, O-alkylation, stereochemistry, NMR, mass spectrometry.
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Sukumar, Narayanasami. "A comparative analysis on x-ray structure of cobalamin binding proteins." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1514. http://dx.doi.org/10.1107/s205327331408485x.
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Vitamin B12 (Cobalamin;Cbl;B12; Figure) is a water soluble vitamin and is an essential component for the growth and development of many eukaryotes and prokaryotes organisms. B12 coordinates a cobalt ion in the center of the ring through the four pyrrole nitrogen atoms, the fifth ligand is dimethylbenzimidazole (DMB) moiety and the sixth ligand can be methyl group, deoxyadenosyl, cyanide or OH-. The structurally diverse groups of B12 binding proteins involved in various important biological functions. B12 adopts either base-on or base-off conformation in B12 binding proteins (Figure). An in-depth analysis on these structures was carried out using PDB coordinates (www.pdb.org) of a carefully chosen database of B12 binding proteins to correlate the overall folding of the molecule with phylogeny, the B12 interactions, and with biological function. The chosen database can be divided into three distinct groups. The first group is B12 transport proteins in mammals and the second is B12 transport proteins in E.Coli. The third group can be broadly clarified as B12-dependent enzymes. Results: The molecular architecture of the B12 binding proteins is diverse. It varies from a two-domain to multi-domain proteins. An analysis on the environment around B12 molecule shows that hydrogen bonds or vander waals interactions are dominant interactions between B12 and protein. Both conventional hydrogen bonds (N-H....X and O-H....X) and weak C-H....X hydrogen bonds play important role in these interactions. The number of protein residues interacting with B12 varies widely from 2 to 18 residues, depending on the nature of biological function. The analysis clearly establishes that B12 is amazingly adoptive to wide range of environments, namely polar, non-polar or charged. The B12 uses its functional groups both at head, corrin ring and in tail region (phosphate or DMB groups) at optimum level to form stable complex with partner proteins. Details will be presented.
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Jørgensen, Christian Juncher, Jacob Mønster, Karsten Fuglsang, and Jesper Riis Christiansen. "Continuous methane concentration measurements at the Greenland ice sheet–atmosphere interface using a low-cost, low-power metal oxide sensor system." Atmospheric Measurement Techniques 13, no. 6 (June 22, 2020): 3319–28. http://dx.doi.org/10.5194/amt-13-3319-2020.
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Abstract. In this paper, the performance of a low-cost and low-power methane (CH4) sensing system prototype based on a metal oxide sensor (MOS) sensitive to CH4 is tested in a natural CH4-emitting environment at the Greenland ice sheet (GrIS). We investigate if the MOS could be used as a supplementary measurement technique for monitoring CH4 emissions from the GrIS with the scope of setting up a CH4 monitoring network along the GrIS. The performance of the MOS is evaluated on the basis of simultaneous measurements using a cavity ring-down spectroscopy (CRDS) reference instrument for CH4 over a field calibration period of approximately 100 h. Results from the field calibration period show that CH4 concentrations measured with the MOS are in very good agreement with the reference CRDS. The absolute concentration difference between the MOS and the CRDS reference values within the measured concentration range of approximately 2–100 ppm CH4 was generally lower than 5 ppm CH4, while the relative concentration deviations between the MOS and the CRDS were generally below 10 %. The calculated root-mean-square error (RMSE) for the entire field calibration period was 1.69 ppm (n=37 140). The results confirm that low-cost and low-power MOSs can be effectively used for atmospheric CH4 measurements under stable water vapor conditions. The primary scientific importance of the study is that it provides a clear example of how the application of low-cost technology can enhance our future understanding on the climatic feedbacks from the cryosphere to the atmosphere.
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Kubicki, M., T. W. Kindopp, M. V. Capparelli, and P. W. Codding. "Hydrogen-bond patterns in 1,4-dihydro-2,3-quinoxalinediones: ligands for the glycine modulatory site on the NMDA receptor." Acta Crystallographica Section B Structural Science 52, no. 3 (June 1, 1996): 487–99. http://dx.doi.org/10.1107/s0108768195011773.
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The crystal structures of five 1,4-dihydro-2,3-quinoxalinediones, antagonists of the NMDA modulatory glycine binding site on the excitary amino acid (EAA) receptor complex, have been determined: (I) 6,7-dinitro-1,4-dihydro-2,3-quinoxalinedione (DNQX); (II) 5,7-dinitro-1,4-dihydro-2,3-quinoxalinedione (MNQX); (III) 6-nitro-1,4-dihydro-2,3-quinoxalinedione hydrate; (IV) 6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione; (V) 5,7-dichloro-1,4-dihydro-2,3-quinoxalinedione dimethylformamide. The crystal structure of the most active compound (II) contains a unique intramolecular N—H...O(NO2) hydrogen bond, which may be important for activity, as semiempirical calculations show that this bond is stable over a wide range of dihedral angles between the planes of the molecule and of the nitro group. In the other compounds the intermolecular hydrogen bonds connect molecules into three-dimensional networks. In compounds (I), (III) and (IV) head-to-tail: π-stacking is found between molecules connected by a center of symmetry. The geometries of the hydrogen-bonded —NH—C=O fragments show evidence of π-cooperativity or resonance-assisted hydrogen bonding. Graph-set analysis of the hydrogen-bond patterns of quinoxalinedione derivatives shows a tendency to form two types of hydrogen-bonding motifs: a centrosymmetric dimeric ring and an infinite chain. Even though this pattern may be modified by the presence of additional hydrogen-bond acceptors and/or donors, as well as by solvent molecules, general similarities have been found. Comparison of all quinoxalinedione structures suggests that the hydrogen-bonding pattern necessary for the biological activity at the glycine binding site contains one donor and two acceptors.
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von Mehren, Margaret, Sujana Movva, Elizabeth A. Handorf, Priscilla Merriam, Jeffrey A. Morgan, Edwin Choy, Eric Daniel Tetzlaff, et al. "Outcomes in the dedifferentiated liposarcoma cohort of SAR-096, a phase II trial of ribociclib in combination with everolimus in advanced dedifferentiated liposarcoma (DDL), and leiomyosarcoma (LMS)." Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021): 11515. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.11515.
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11515 Background: Dedifferentiated liposarcoma (DDL) is characterized by ring chromosomes of chromosone12, which includes amplification of MDM2 and CDK4. Exposure to CDK4 inhibitors in Rb+ leiomyosarcoma (LMS) cell lines leads to decreased cell proliferation, and increased senescence, and G0/G1-phase arrest. When combined, ribociclib a CDK4 inhibitor and everolimus, an mTOR inhibitor show synergistic growth inhibition in multiple tumor models. We hypothesized that this combination could lead to increased disease control in patients with DDL. Methods: This study enrolled patients (pts) into one of two cohorts: DDL or Rb+ LMS. LMS pts were required to have 1 prior line of therapy; DDL pts required no prior therapy. There were no limits to prior therapies in either group. Measurable disease by RECIST 1.1 was also required. Ribociclib was given at 300 mg daily for 21/28 days and everolimus was given continuously at 2.5 mg daily in 28 day cycles. The primary endpoint was progression free rate at 16 weeks. A Simon two-stage design was utilized and if at least 8 out of 24 pts were progression free at 16 weeks, the treatment was declared promising for the cohort. Here in we present data on the DDL cohort. Results: To date, 21 DDS pts, median age of 63 (range 40-79), of which 43% (n = 9) female were treated. Median prior lines of therapy was 1 (range 0-6). Of 19 pts with complete data, 8 (42%) met the primary endpoint of non-progression at 16 weeks. Confirmed partial response was seen in 2 pts (10%). Median PFS was 16 weeks, and stable disease occurring as best response in 11 (55%) pts. Grade 3-4 toxicities were uncommon except for lymphopenia (24%) and neutropenia (33%); no episode of neutropenic fever were observed. There was one death on study secondary to myocardial infarction, considered possibly related to therapy. Results of optional tissue biopsies pre and on therapy obtained to assess pharmacodynamic changes in PTEN, pAKT, CDK4, Rb and pS6 will be presented. Conclusions: The combination of ribociclib and everolimus demonstrates activity in DDL with prolonged stable disease (>16 weeks) meeting the primary protocol endpoint. Notably partial responses were also observed. The combination was well tolerated with acceptable side effects. Updated outcomes will be presented. Clinical trial information: NCT03114527.
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Stojanovic, Ksenija, Branimir Jovancicevic, Dragomir Vitorovic, Yulia Golovko, Galina Pevneva, and Anatoly Golovko. "Evaluation of saturated and aromatic hydrocarbons oil-oil maturity correlation parameters (SE Pannonian Basin, Serbia)." Journal of the Serbian Chemical Society 72, no. 12 (2007): 1237–54. http://dx.doi.org/10.2298/jsc0712237s.
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Twenty three crude oils from the Serbian part of the Pannonian Basin (14 from the Vojvodina Province and 9 from the Drmno Depression) were investigated, aimed at an evaluation of oil-oil maturity correlation parameters based on the distribution and abundance of saturated biomarkers and alkylarene constituents. Factor and cluster analyses were used for this purpose. Factor analyses using varimax rotation were first run separately, i.e., of maturity parameters based on the abundance of (a) n-alkanes and isoprenoids, (b) steranes and triterpanes, (c) alkylnaphthalenes, and (d) alkylphenanthrenes. These analyses yielded 9 important "maturity factors". Eight of them, showing higher than 30 % of variance, were further involved in another factor analysis, as well as in cluster analysis using the Ward method. In this way, all maturity parameters based on saturated biomarkers and alkylarenes were evaluated and ranged, considering the fact that the observed factors represented their linear combinations. The results showed that in the correlation of crude oils from the Serbian part of the Pannonian Basin, the most important were maturity parameters based on isomerization reactions involving one methyl group in thermodynamically less stable ?-methylnaphthalenes, ethylnaphthalenes, dimethylnaphthalenes and methylphenanthrenes, and their change into more stable isomers with the methyl group in the ?-position in the aromatic ring. Processes constituting high loadings factor 2 and factor 3 parameters were also defined. Hierarchy between the "factors" and parameters were controlled, and approved, by cluster analysis using the Ward method. Finally, the investigated crude oils were correlated by factor and cluster analyses, using all the important "maturity factors". Differences in maturity were observed between the Vojvodina and Drmno Depression crude oils, as well as between oils originating from South Banat, North Banat and the Velebit oil field (Vojvodina locality).
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Pihura, Oksana, and Bohdan Zabavsky. "Commutative morphic rings of stable range 2." Proceedings of the International Geometry Center 8, no. 3-4 (February 13, 2020): 65–68. http://dx.doi.org/10.15673/tmgc.v8i3-4.1608.
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It is know that a left quasi-morphic ring R is a ring of stable range 1 if and only if dim R = 0.
In this paper it is shown that a commutative morphic ring R is a ring of stable range 2 if and only if dimR= 1.
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Zabavsky, Bohdan, and Oleh Romaniv. "A Bezout ring of stable range 2 which has square stable range 1." Communications in Algebra 47, no. 12 (June 6, 2019): 5392–97. http://dx.doi.org/10.1080/00927872.2019.1623239.
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Dmytruk, A. A., A. I. Gatalevych, and M. I. Kuchma. "Stable range conditions for abelian and duo rings." Matematychni Studii 57, no. 1 (March 31, 2022): 92–97. http://dx.doi.org/10.30970/ms.57.1.92-97.
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The article deals with the following question: when does the classical ring of quotientsof a duo ring exist and idempotents in the classical ring of quotients $Q_{Cl} (R)$ are thereidempotents in $R$? In the article we introduce the concepts of a ring of (von Neumann) regularrange 1, a ring of semihereditary range 1, a ring of regular range 1. We find relationshipsbetween the introduced classes of rings and known ones for abelian and duo rings.We proved that semihereditary local duo ring is a ring of semihereditary range 1. Also it was proved that a regular local Bezout duo ring is a ring of stable range 2. In particular, the following Theorem 1 is proved: For an abelian ring $R$ the following conditions are equivalent:$1.$\ $R$ is a ring of stable range 1; $2.$\ $R$ is a ring of von Neumann regular range 1.
The paper also introduces the concept of the Gelfand element and a ring of the Gelfand range 1 for the case of a duo ring. Weproved that the Hermite duo ring of the Gelfand range 1 is an elementary divisor ring (Theorem 3).
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Chen, Huanyin, and Miaosen Chen. "Unit1-stable range for ideals." International Journal of Mathematics and Mathematical Sciences 2004, no. 46 (2004): 2477–82. http://dx.doi.org/10.1155/s0161171204402361.
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We investigate necessary and sufficient conditions under which a ring satisfies unit1-stable range for an ideal. As an application, we prove thatRsatisfies unit1-stable range forIif and only ifQM2(R)satisfies unit1-stable range forQM2(I).
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Kelaidi, Charikleia, Dimitrios Kokkinidis, Maria Protopappa, Georgios Papaioannou, Ioannis Batsis, Chrysa Apostolou, Kostas Stamatopoulos, Anastasia Athanasiadou, Achilles Anagnostopoulos, and Chrysanthi Vadikoliou. "Extreme Thrombocytosis Under Azacitidine in Patients with Myelodysplastic Syndrome." Blood 120, no. 21 (November 16, 2012): 4961. http://dx.doi.org/10.1182/blood.v120.21.4961.4961.
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Abstract Abstract 4961 Background: Platelet increase under azacitidine in patients with myelodysplastic syndrome (MDS) has been acknowledged as an early predictive factor of response to treatment. However, extreme thrombocytosis under azacitidine has not been reported. Methods: We studied consecutive patients with MDS or MDS/myeloproliferative neoplasm (MDS/MPN) who had platelet counts near or over 1, 000 G/L under azacitidine. Results: Four patients, sex ratio 1:1, with median age of 65 years, had extreme thrombocytosis under azacitidine. Baseline characteristics were: WHO classification RAEB-2/CMML-1/CMML-2 in 2/1/1 patients, median platelet count 248 G/L (<400 G/L in all), normal karyotype/+8, −9/−7 in 2/1/1 patients, IPSS low/int-2/high in 1/2/1 patients. None had reticulinic fibrosis or ring sideroblasts>15% at baseline. A median number of 8 cycles of azacitidine was administered. Individual platelet counts reached 2, 960 G/L, 800 G/L, 1, 188 G/L and 2, 740 G/L. Thrombocytosis occured early after treatment onset or resumption (Figure 1). Histologic findings under treatment were: Increased cellularity (N=4), micromegakaryocytes and other signs of megakaryocytic dysplasia (N=4), reticulinic fibrosis grade I and II in 1 and 2 patients, respectively. JAK2 V617F mutation was detected in 1 patient (with maximum platelet count of 2, 900 G/L) and was undetectable in the remaining patients. None had a thrombotic or hemorrhagic event. Two patients had a concomitant increase of WBC count. Response to azacitidine was CR, PR and stable disease in 1/1/2 patients. Three patients received hydroxyurea (HU) in addition to azacitidine and one patient underwent hematopoietic stem cell transplantation (HCT). AML transformation occurred in 1 patient 25 months after azacitidine onset. Median overall survival after azacitidine onset was 25 months. Conclusion: Extreme thrombocytosis of the range of essential thrombocytosis, with megakaryocytic dysplasia and hyperplasia, was noted under azacitidine in 4 patients with MDS-MDS/MPN and normal baseline platelet count. Hypothetically, azacitidine may induce the expression of critical genes of megakaryopoiesis or platelet release in patients with rare mutations. Notably, JAK2 mutation was detected in only one patient. Alternatively, demethylation could unmask an underlying unclassified MDS/MPN similar to RARS-T. Disclosures: No relevant conflicts of interest to declare.
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Camarin Sanchez, Efrain Isaias, Ervin Saúl Enciso López, Benigno Rodriguez, Diana Alejandra Villegas Osorno, Omar Serrano Villamayor, Daniela Shveid Gerson, José Fabián Martínez-Herrera, et al. "Clinicopathological characteristics of patients with HER2-positive gastric and gastroesophageal junction cancer in a single tertiary hospital." Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021): e16105-e16105. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.e16105.
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e16105 Background: Gastric cancer (GC) and gastroesophageal junction cancer (GEJ) are the second most prevalent and lethal digestive malignancies worldwide. According to GLOBOCAN 2020, the incidence in Mexican population is 4.5% and represents 7% of all deaths. In GC and GEJ, the frequency of HER2 overexpression varies widely in the literature. Actually the blocking anti-HER2 is the standard therapy in GC and GEJ with overexpression HER2 according to the ToGa Trial. There are few studies that describe this population in mexican patients. Methods: We conducted a retrospective, observational analysis. Medical records of patients with GC or GEJ cancer from January 2015 to January 2021 were reviewed. A total of 91 patients were retrieved from the pathology database. Clinicalpathologic features collected were sex, age, pTNM stage (AJCC 8th edition), histology type, HER-2 status, metastases sites and treatment. The HER-2 determination was performed in all cases with immunohistochemistry (IHQ). Results: We found 10 patients with GC and GEJ with HER-2 overexpression by IHC, five patients with FISH positive and 2 of them with amplification by next generation sequence (FoundationOne). The median age was 56.9 years (27-68). There were more male patients (n = 8) than female patients (n = 2), with male/female ratio of 4:1. 8 patients had performance status (PS) 0 or 1, and the rest PS 2. The primary site was gastric carcinoma in 3 patients, and in 7 the tumor was located in GEJ. The clinical stage at diagnosis in 7 patients was metastatic, and 3 locally advanced. The most common sites of metastasis were lung (n = 5), liver (n = 4), and pleural, bone and central nervous system (each one with one patient). Intestinal-type GCs were most prevalent with 8 patients, and the rest were diffuse and signet ring cells. All patients received anti-HER2 blockade, 6 in the first line therapy, and 4 patients in the second line or more. Regarding the backbone regimen of the trastuzumab based therapy, fluoropyrimidine/platinum were the mainstay in 9 patients, and 1 with platinum and taxane scheme. Median number of cycles of trastuzumab was 8 (range, 4-24). The tumor responses were as follows: complete response (CR) 10%, partial response (PR) 30%, stable disease 50% and progressive disease 1 patient. The median progression-free survival was 6.6 months (1.3-23.1 months), and a median of overall survival was 21 months (6.4-51.5 months). The most frequently reported adverse events were diarrhoea in 3 patients (all grade 2), and mucositis in 1 patient. Cardiac adverse events were not reported. Conclusions: In our cohort, the prevalence of HER2 overexpression by IHC was 11%. In previous reports, the most important ToGa trial, 22% of the patients with metastatic GC and GEJ were HER2 positive. The PFS and OS in ToGa trial were 13.8 and 17.1 months respectively. By comparison our cohort the PFS and OS in ToGa trial were 6.6 and 21 months.
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Zabavsky, Bohdan. "Rings of dyadic range 1." Journal of Algebra and Its Applications 18, no. 11 (August 19, 2019): 1950206. http://dx.doi.org/10.1142/s0219498819502062.
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In this paper, we introduced the concept of a ring of a right (left) dyadic range 1. We proved that a Bezout ring of right (left) dyadic range 1 is a ring of stable range 2. And we proved that a commutative Bezout ring is an elementary divisor ring if and only if it is a ring of dyadic range 1.
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Ravenel, Douglas C., and W. Stephen Wilson. "The Hopf Ring for P(n)." Canadian Journal of Mathematics 48, no. 5 (October 1, 1996): 1044–63. http://dx.doi.org/10.4153/cjm-1996-054-2.
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AbstractWe show that , the E-homology of the Ω-spectrum for P(n), is an E* free Hopf ring for E a complex oriented theory with In sent to 0. This covers the cases and . The generators of the Hopf ring are those necessary for the stable result. The motivation for this paper is to show that P(n) satisfies all of the conditions for the machinery of unstable cohomology operations set up in [BJW95]. This can then be used to produce splittings analogous to those for BP done in [Wil75]
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Moyo, Tamara K., Justin M. Watts, Barry S. Skikne, Jason H. Mendler, Virginia M. Klimek, Sheau-Chiann Chen, Run Fan, et al. "Preliminary Results from a Phase II Study of the Combination of Pevonedistat and Azacitidine in the Treatment of MDS and MDS/MPN after Failure of DNA Methyltransferase Inhibition." Blood 134, Supplement_1 (November 13, 2019): 4236. http://dx.doi.org/10.1182/blood-2019-130003.
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After failure of DNA methyltransferase inhibition (DNMTi) there is no standard of care therapy for high-risk myelodysplastic syndromes (MDS), and median survival for higher risk disease is less than 6 months (Prebet et al, JCO 2011; Jabbour et al, Cancer 2015). Pevonedistat, a first in human small molecule inhibitor of the NEDD8 activating enzyme (NAE), downregulates Cullin ring ligases (CRL) which interferes with the shuttling and degradation of proteins in the proteasome and leads to accumulation of CRL substrates. Combining pevonedistat (Pev) with azacitidine (AZA) resulted in synergistic cell killing in in vitro and xenograft models of acute myeloid leukemia (AML) (Smith et al, Blood 2011), elicited favorable response rates in treatment naïve elderly or unfit AML patients (Swords et al Blood 2018), and is currently under study in treatment-naïve MDS. The study presented herein (NCT03238248) investigates the utility of adding pevonedistat to azacitidine (PevAz) after DNMTi failure in MDS and MDS/MPN overlap syndromes. Methods: In this on-going single-arm phase II study, MDS and MDS/MPN patients were eligible if they were refractory to DNMTi treatment, progressing after at least 2 cycles of therapy; had failed to achieve a complete remission (CR) after at least 4 cycles of DNMTi therapy; or had relapsed after an initial response to DNMTi therapy. Enrolled subjects received AZA 75mg/m2 sc/iv daily on days 1-5 and Pev 20mg/m2 iv on days 1, 3 and 5 of each 28-day cycle. Survival is the primary endpoint and is assessed at regularly scheduled study visits and every 3 months after ending protocol-directed therapy. Hematologic and bone marrow response rates are secondary endpoints. Responses to treatment are determined by the MDS International Working Group (IWG) response criteria (Cheson et al, Blood 2006) or for MDS/MPN, by the modified MDS/MPN IWG response criteria (Savona et al, Blood 2015). Results: As of the data cutoff on 15 MAR 2019, 23 subjects (21 with MDS, 2 with MDS/MPN) had enrolled and initiated treatment. Subjects had previously been treated with AZA (n=11/23), decitabine (n=11/23), and ASTX727 (n=4/23); some subjects had been treated with more than one DNMTi prior to enrollment. Median number of cycles of any prior DNMTi therapy was 7 (range 2-35). 65% of subjects were female. Median age at enrollment was 67 years (range 51 - 85). 65% had Intermediate-2 or High risk disease by IPSS at time of enrollment. Median number of PevAz cycles completed prior to the data cutoff was 4 (range 1-19). One subject had not reached the first response assessment at the time of the data cutoff and data was unavailable for one subject. The overall response rate including complete and partial remission, hematologic improvement and clinical benefit (CB) was 42.9% (9/21), and CR rate (including 1 CR + 4 marrow CR) was 23.8% (5/21) with a median duration of response (DOR) of 8.7m (range 2.8m-15.7m). An additional 38.1% (8/21) had stable disease as best response (Table 1). The most common Grade >2 adverse events (any attribution) include thrombocytopenia (39%), anemia (35%), leukopenia (26%), neutropenia (22%), infections (17%), and febrile neutropenia (13%). Six subjects experienced Grade ≤ 2 elevations in AST/ALT and 4 had Grade ≤ 2 elevation in bilirubin, whereas only one subject experienced Grade > 2 LFT abnormality (increase in ALT). There was one death on study due to intracerebral hemorrhage related to a previously undiagnosed metastatic carcinoma. PevAz treatment was discontinued in other subjects due to disease progression (n=7), adverse event (n=1), lack of response (n=1), or to pursue allogeneic stem cell transplant after achieving a satisfactory response to PevAz (n=3). Ten subjects were continuing PevAz therapy on study as of the data cutoff. Summary: PevAz was well-tolerated in MDS and MDS/MPN patients who had previously failed DNMTi, with the most common adverse events of cytopenias, which are a common feature of these diseases. 5/21 subjects achieved CR/mCR with meaningful DOR, and the ORR of 42.9% exceeded expectations for MDS patients with previous failure of DNMTi therapy; both MDS/MPN patients responded with CR and CB. For these patients whose treatment options are limited and prognosis very poor, these preliminary data are especially encouraging and warrant further investigation. This therapy combination is being tested in a phase 3 study in treatment naïve high risk MDS, CMML and low-blast AML. Disclosures Watts: Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Research Funding. Strickland:Astellas Pharma: Consultancy; Sunesis Pharmaceuticals: Research Funding; AbbVie: Consultancy; Jazz: Consultancy; Kite: Consultancy; Pfizer: Consultancy. Byrne:Karyopharm: Research Funding. Bradley:AbbVie: Other: Advisory Board. Savona:Sunesis: Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Patents & Royalties.
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Daher, May, Juliana Elisa Hidalgo Lopez, Jasleen K. Randhawa, Kausar Jabeen Jabbar, Naveen Pemmaraju, Gautam Borthakur, Tapan M. Kadia, et al. "Updated Phase II Study of Targeted Subcutaneous (SC) Bortezomib for Patients with Low- or Intermediate-1 (Int-1)-Risk Myelodysplastic Syndrome (MDS) with Evidence of NF-κb Activation." Blood 128, no. 22 (December 2, 2016): 3191. http://dx.doi.org/10.1182/blood.v128.22.3191.3191.
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Abstract Introduction MDS has been linked to constitutive activation of genes involved in the nuclear factor-kappaB (NF-κB) pathway [Wei et al. Leukemia 2013; Braun et al. Blood 2006]. Hence, NF-kB is an attractive therapeutic target in this disease. Bortezomib is a proteosome inhibitor with inhibitory activity against NF-κB. We designed a phase II trial of SC bortezomib in patients with low- to intermediate (low/int-1)-risk MDS and evidence of NF-κB activation to determine its therapeutic activity in these patients. Methods In this single-arm phase II study in low/int-1-risk MDS patients, bortezomib was administered at 1.3 mg/m2 SC on days 1, 4, 8, and 11 in a 21-day cycle for a maximum of 2 years of therapy. Eligibility criteria included age ≥18 years, adequate performance status and organ function, and having received at least 1 prior therapy. Patients with grade 2 or greater peripheral neuropathy at baseline were excluded. Patients were prescreened prospectively for enrollment by assessing cellular levels of the phosphorylated NF-κB subunit p65 (pp65) in their marrow. This was performed by immunofluorescence with phospho-Ser276 in bone marrow aspirate smears in the Department of Hematopathology (CLIA regulations). Patients were eligible if at least 5% of all nucleated marrow cells were positive for pp65 staining. pp65 levels were assessed again on day 21 of cycles 1 and 2 and then as clinically indicated. Responses were assessed according to IWG [Cheson et al. Blood 2000; Cheson et al, Blood 2006]. The study could accrue a maximum of 40 patients if there were at least a 95% chance of at least a 15% ORR. Results Beginning 9/2013, we enrolled 15 patients with a median age of 71 years (range 56 - 87). Median marrow blast percentage was 1.9% (range 0 - 5%). Eleven patients (73%) had diploid cytogenetics, 2 had del(20q), 1 had Y-, and 1 had del(5q). All had lower-risk MDS by IPSS (low 33.3%, int-1 66.7%). All were transfusion dependent (6 both platelets and red cells (PRBCs), 1 only platelets, 8 only PRBCs). Hypomethylating agents had failed in 12 of the patients. At a median follow-up interval of 22 weeks, the ORR was 20%; 3 patients had hematologic improvement with a mean duration of response of 14.3 weeks (range 4-21). Eight patients had stable disease, and 4 had progression. No correlation between clinical response and molecular or cytogenetic data was observed. Eventually, all patients were taken off study: 7 due to increasing transfusion requirements, 2 worsening cytopenia, 1 lack of response, 1 increased blasts, and 1 grade 2 neuropathy; 2 withdrew by choice, and 1 patient died from causes unrelated to the study. Four patients experienced ≥ 1 grade 3 toxicity. No grade 4 toxicity was observed. Seven patients experienced grade 1 (n=4) or grade 2 (n=3) neuropathy. Morphologic review (n=14) in the responders group (n=3) showed reduction in ring sideroblasts (RS) in 2 patients (60 to 47% and 43% to 30%). Two patients, including 1 of those with reduced RS, had improvement of dysplasia (from severe trilineage dysplasia to moderate bilineage dysplasia). No changes in cytogenetic studies were found in the responder group. Among nonresponders (n=11), 3 had new acquired cytogenetic abnormalities, 3 had worsening dysplasia, and 2 had increase in blast count (1% to 3% and 1% to 4%). Two had no morphologic changes during treatment. One showed improvement in dysplasia and blast count (2% to 0%) and no changes in cytogenetics. Interestingly, 3 nonresponders showed RS reduction during treatment (18% to 1%, 85% to 45%, and 6% to 0%). The median pp65 level at baseline was 30.87% (range 7 - 70%). The pp65 level decreased in 7 of the 15 patients (46.7%), in 6 of them by the end of cycle 1. Interestingly, the 3 responders were among the 7 patients who had a decrease in pp65 level. Eventual loss of response in these patients was accompanied by return to a higher pp65 level. In nonresponders, the pp65 level increased in 7, decreased in 2, and remained unchanged in 1; for 1, the sample was suboptimal. Conclusions In previously treated lower-risk MDS patients, SC Bortezomib was well tolerated and resulted in hematologic improvement and decrease in RS. NF-κB activation, measured by pp65 level, can be a useful biomarker to select patients with lower-risk MDS who could benefit from therapies that target this pathway. The NF-κB pattern of expression suggests an inverse relationship between treatment response and NF-κB level, with associated improvement in bone marrow morphology. Disclosures Konopleva: Calithera: Research Funding; Cellectis: Research Funding. Cortes:ARIAD: Consultancy, Research Funding; Bristol-Myers Squib: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding.
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Tang, Yongxing, Chunlin He, Gregory H. Imler, Damon A. Parrish, and Jean'ne M. Shreeve. "Ring closure of polynitroazoles via an N,N′-alkylene bridge: towards high thermally stable energetic compounds." Journal of Materials Chemistry A 6, no. 18 (2018): 8382–87. http://dx.doi.org/10.1039/c8ta02704h.
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Chen, H. V., and A. Y. M. Chin. "A note on regular rings with stable range one." International Journal of Mathematics and Mathematical Sciences 31, no. 7 (2002): 449–50. http://dx.doi.org/10.1155/s0161171202109021.
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Zabavs’kyi, B. V., and B. M. Kuznits’ka. "A Stable Range of Class Full Matrices over Elementary Divisor Ring." Ukrainian Mathematical Journal 66, no. 5 (October 2014): 792–95. http://dx.doi.org/10.1007/s11253-014-0973-0.
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Serbinovskiy, Mikhail Yu, Natal'ya A. Vasil'yeva, and Olga V. Popova. "ON COMPLEXATION IN PROCESS OF CHEMICAL COPPER PLATING FROM SOLUTIONS CONTAINING POLYVINYLPYRROLIDONE." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 2 (April 7, 2017): 26. http://dx.doi.org/10.6060/tcct.2017602.5478.
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A formation of multifunctional composite coatings with a copper matrix by chemical vapor deposition is an effective method of modifying the surface of metals and non-metals and the increase in the deposition rate of coatings. It is important that the copper complex compounds are formed during chemical vapor deposition coatings and are included in the coatings composition. During the work by methods of thermogravimetric analysis and IR spectroscopy the composite coatings with copper matrix obtained from solutions containing copper sulphate and polyvinylpyrrolidone were studied. The results of thermogravimetry and IR spectroscopy of these components were presented. Samples of composite coatings for IR spectroscopy were obtained as a suspension of the coatings in vaseline oil. Deposited coating was scraped off from the substrate, and then was triturated in an agate mortar with vaseline oil until they formed a stable not stratified suspension. These suspensions were analyzed. The samples for thermogravimetry containing copper sulfate and polyvinylpyrrolidone were obtained by mixing these components. The following proofs of interaction in polyvinylpyrrolidone - copper sulphate system with forming a complex of polyvinylpyrrolidone - copper and includings of this complex into the coating were obtained. The differences of thermogravimetric curves of the mixture CuSO4 5H2O and polyvinylpyrrolidone were established. They are softening temperature increasing in the polymer material on 30 ... 35 °С towards to the softening temperature of polyvinylpyrrolidone, the appearance of the endothermic process, probably associated with the interaction of the polyvinylpyrrolidone with the copper, and the increase in the thermal stability of the polymer component of the system on 50-60 °С, which can be also with the result of complexation of polyvinylpyrrolidone - copper. The estimated structure of this complex, which reflects the results of the IR-spectrogram of the composite coatings analysis was presented. The IR spectra have absorption bands with wave numbers corresponding to the stretching vibrations of C-H bonds in the aromatic ring of polyvinylpyrrolidone, the stretching vibrations of the group – CH2 - and C-N bonds, which are also typical for the polyvinylpyrrolidone. This indicates the presence of polyvinylpyrrolidone in the coating or in its complex compound. In the spectra of the coatings the absorption bands in the range of 1750-1250 cm-1 are presented, which correspond to the stretching vibrations of C=O in the aromatic part of polyvinylpyrrolidone compound, in particular, in the group -CONHR, but they are shifted on about 50 cm-1 with respect to the same bands in the spectra of polyvinylpyrrolidone solution. Such shift is typical for the complex compounds of polyvinylpyrrolidone - copper which caused the C=O bond deformation, which occurs during the formation of additional bond of oxygen and copper atoms: C=O ∙∙∙ Cu, and indicates the presence of such complexes in a coating.Forcitation:Serbinovskiy M.Yu., Vasil'yeva N.A., Popova O.V. On complexation in process of chemical copper plating from solutions containing polyvinylpyrrolidone. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 2. P. 26-32.
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Blaschette, Armand, Karin Linoh, Dietrich Koch, and Ludger Ernst. "Polysulfonylamine, XV [1] Synthese von N,N,N′,N′-Tetramesyl-dicarbonsäurediamiden. Cyclisierung von N,N,N′,N′-Tetramesyl-bernsteinsäurediamid zu γ-DimesyIamino-Δβγ-butenolid / Polysulfonylamines, XV [1]. Synthesis of N,N,N′,N′-Tetramesyl Dicarboxylic Diamides. Cyclization of N,N,N′,N′-Tetramesyl Succinic Diamide to γ-Dimesylamino-Δβγ-butenolide." Zeitschrift für Naturforschung B 44, no. 4 (April 1, 1989): 465–74. http://dx.doi.org/10.1515/znb-1989-0415.
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N, N, N′, N′ -Tetramesyl dicarboxylic diamides Ms2NC(O)-Q-C(O)NMs2 [Q = (CH2)n with n = 0 (2a), 2 (2b), 3 (2c), 4 (2d); Q = o-phenylene (2e)] were prepared by reacting AgNMs2 (1) with the appropriate dicarboxylic dichlorides in acetonitrile at room temperature (2a, 2 c-2e) or at 0 °C (2b), respectively. Under similar conditions, malonic dichloride undergoes an elimination, forming AgCl, HNMs2 and probably polymeric C3O2. At 20 °C in CH3CN, the succinic acid derivative 2b eliminates one mole of HNMs2 and, by ring closure, yields γ-dimesylamino-Δβγ- butenolide (4a), the first example of a stable γ-amino-Δβγ-butenolide. Treatment of 4a with aqueous NaOH results in the formation of NaNMs2 and sodium succinate. Crystalline 4a is thermally stable at 100 °C; no signs of an isomerization 4a → γ-dimesylamino-Δαγ-butenolide could be detected. Unlike the structurally related α-angelicalactone (4c), whose bromination affords the saturated dibromolactone 9 as a mixture of cis- and mws-isom ers, 4a adds bromine (20 °C, CHCl3) under ring cleavage to form BrC(O)CH2CHBrC(O)NMs2 (7). The new compounds 2, 4a and 7 as well as the stereoisomers of 9 were characterized by spectroscopic (1H and 13C NMR, MS, IR) and analytical methods. In order to obtain reference values for the chemical shifts of 7, the following new compounds were prepared: CH3(CH2)2C(O)NMs2 (10c, from 1 and butvryl chloride); CH3CH2CHBrC(O)NMs2 (12c, from 1 and 2-bromobutyryl bromide); C2H5OC(O)CH 2CHBrC(O)NMs2 (13, from 7 with ethanol and from 4a by simultaneous reaction with bromine and ethanol).
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Bodach, Alexander, Thomas Bernert, Michael Fischer, Morten Brix Ley, and Claudia Weidenthaler. "Polymorphism of dimethylaminoborane N(CH3)2-BH2." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, no. 2 (March 26, 2021): 299–306. http://dx.doi.org/10.1107/s2052520621001979.
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Dehydrocoupling of the adduct of dimethylamine and borane, NH(CH3)2-BH3 leads to dimethylaminoborane with formal composition N(CH3)2-BH2. The structure of this product depends on the conditions of the synthesis; it may crystallize either as a dimer in a triclinic space group forming a four-membered ring [N(CH3)2-BH2]2 or as a trimer forming a six-membered ring [N(CH3)2-BH2]3 in an orthorhombic space group. Due to the denser packing, the six-membered ring in the trimer structure should be energetically more stable than the four-membered ring. The triclinic structure is stable at low temperatures. Heating the triclinic phase above 290 K leads to a second-order phase transition to a new monoclinic polymorph. While the crystal structures of the triclinic and orthorhombic phases were already known in the literature, the monoclinic crystal structure was determined from powder diffraction data in this study. Monoclinic dimethylaminoborane crystallizes in space group C2/m with the boron and nitrogen atoms located on the mirror plane, Wyckoff position 4i, while the carbon and hydrogen atoms are on the general position 8j.
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GILLESPIE, JAMES. "AC-GORENSTEIN RINGS AND THEIR STABLE MODULE CATEGORIES." Journal of the Australian Mathematical Society 107, no. 02 (October 29, 2018): 181–98. http://dx.doi.org/10.1017/s1446788718000290.
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We introduce what is meant by an AC-Gorenstein ring. It is a generalized notion of Gorenstein ring that is compatible with the Gorenstein AC-injective and Gorenstein AC-projective modules of Bravo–Gillespie–Hovey. It is also compatible with the notion of $n$ -coherent rings introduced by Bravo–Perez. So a $0$ -coherent AC-Gorenstein ring is precisely a usual Gorenstein ring in the sense of Iwanaga, while a $1$ -coherent AC-Gorenstein ring is precisely a Ding–Chen ring. We show that any AC-Gorenstein ring admits a stable module category that is compactly generated and is the homotopy category of two Quillen equivalent abelian model category structures. One is projective with cofibrant objects that are Gorenstein AC-projective modules while the other is an injective model structure with fibrant objects that are Gorenstein AC-injectives.
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Heshmat, H., and O. Pinkus. "Experimental Study of Stable High-Speed Oil Rings." Journal of Tribology 107, no. 1 (January 1, 1985): 14–22. http://dx.doi.org/10.1115/1.3260996.
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An experimental investigation was conducted on the behavior of oil rings for bearing sizes ranging from 75 mm (3 in.) to 305 mm (12 in.) in diameter. The characteristics of rings through several regimes of operation were determined up to journal speeds at which the ring becomes unstable and oil delivery ceases. Emphasis is placed on the fact that, of the oil lifted up by the ring, only a small portion is actually delivered to the bearing clearance so that in most cases the bearings run under starved conditions. A parametric study of ring weight, size, shape, tooth depth and orientation, as well as ring material yielded an optimum ring configuration from the standpoint of maximum oil delivery to the bearing. In addition, a stabilizer in the shape of an anchored spring leaf whose free end projects into the film between ring and journal surfaces was designed and shown to contribute substantially to raising the amount of oil delivered and to extending the range of stable ring operation.
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Harris, John C. "On Certain Stable Wedge Summands of B(𝓩/p)n+." Canadian Journal of Mathematics 44, no. 1 (February 1, 1992): 104–18. http://dx.doi.org/10.4153/cjm-1992-006-8.
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AbstractCampbell and Selick have given a natural decomposition of the cohomology of an elementary abelian p-group over the Steenrod algebra. We study the corresponding stable wedge summands of the classifying space B(𝓩/p)n+using representation theory and explicit idempotents in the group ring 𝓕p[GLn(𝓩/p)].
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Glover, Stephen A., Adam A. Rosser, Avat (Arman) Taherpour, and Ben W. Greatrex. "Formation and HERON Reactivity of Cyclic N,N-Dialkoxyamides." Australian Journal of Chemistry 67, no. 3 (2014): 507. http://dx.doi.org/10.1071/ch13557.
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Cyclic N,N-dialkoxyamides have been made, for the first time, by hypervalent iodine oxidation of β- and γ-hydroxyhydroxamic esters 17, 19, and 21. The fused γ-lactam products, N-butoxy- and N-benzyloxybenzisoxazolones (22a and 22b), are stable while alicyclic γ-lactam and δ-lactam products, 24 and 25, although observable by NMR spectroscopy and ESI-MS are unstable at room temperature, undergoing HERON reactions. The γ-lactam 24 undergoes exclusive ring opening to give a butyl ester-functionalised alkoxynitrene 28. The δ-lactam 25, instead, undergoes a HERON ring contraction to give butyrolactone (27). The structures of model γ- and δ-lactams 6, 7, and 8 have been determined at the B3LYP/6-31G(d) level of theory and the γ-lactams are much more twisted than the acyclic N,N-dimethoxyacetamide (5) resulting in a computed amidicity for 6 of only 25 % that of N,N-dimethylacetamide (3). The HERON reactions of N,N-dimethoxyacetamide (5) and alicyclic models 6 and 8 have been modelled computationally. The facile ring opening of 6 (EA = 113 kJ mol–1) and ring contraction of 8 (EA = 145 kJ mol–1) are predicted well, when compared with the HERON rearrangement of 5 (EA = 178 kJ mol–1).
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Ishida, Masatoshi, Kensuke Nakahara, Ryuichi Sakashita, Tomoya Ishizuka, Motonori Watanabe, Hidemitsu Uno, Atsuhiro Osuka, and Hiroyuki Furuta. "N-confused phlorin: a stable dihydroporphyrin isomer containing a confused pyrrole ring." Journal of Porphyrins and Phthalocyanines 18, no. 10n11 (October 2014): 909–18. http://dx.doi.org/10.1142/s1088424614500692.
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Synthesis of bona fide N -confused phlorin derivatives through simple chemical reduction of N -confused porphyrin precursors using sodium borohydride, p-toluenesulfonyl hydrazide, etc. is described. Spectroscopic, X-ray diffraction analyses and DFT-assisted calculations of these species support the nonaromatic phlorin electronic structure.
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Sinchuk, S. "Injective stability for unitary K1, revisited." Journal of K-Theory 11, no. 2 (March 6, 2013): 233–42. http://dx.doi.org/10.1017/is013001028jkt211.
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AbstractWe prove the injective stability theorem for unitary K1 under the usual stable range condition on the ground ring. This improves the stability theorem of A. Bak, V. Petrov and G. Tang where a stronger Λ-stable range condition was used.
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LAM, T. Y. "A CRASH COURSE ON STABLE RANGE, CANCELLATION, SUBSTITUTION AND EXCHANGE." Journal of Algebra and Its Applications 03, no. 03 (September 2004): 301–43. http://dx.doi.org/10.1142/s0219498804000897.
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The themes of cancellation, internal cancellation, substitution and exchange have led to a lot of interesting research in the theory of modules over commutative and noncommutative rings. This article provides a quick and relatively self-contained introduction to the voluminous work in this area, using the notion of the stable range of rings as a unifying tool. With only a small number of exceptions, all theorems stated here are proved in full, modulo basic facts in the theory of modules and rings available in standard textbooks on ring theory.
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Möhrle, H., and R. Nießen. "Reaktionen von Isochinolinium-Salzen mit Hydroxylamin-Derivaten, 1. Mitteilung. N-(Nitrophenyl)-substituierte Verbindungen/Reactions of Isoquinolinium Salts with Hydroxylamine Derivatives, 1st Communication. N-(Nitrophenyl) Substituted Compounds." Zeitschrift für Naturforschung B 54, no. 2 (February 1, 1999): 225–33. http://dx.doi.org/10.1515/znb-1999-0211.
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N-(Nitrophenyl) substituted isoquinolinium salts reacted with nucleophiles of the hydroxylamine type to different products depending on the electron withdrawing strength of the substituent. Mononitro compound 8 produced only the cyclic hydroxylamine 9a, the trinitroderivative 5 solely the ring cleaved oximes. The dinitro substance 1 held an intermediate position and gave rise to a labile cyclic hydroxylamine and a more stable ring opened Z-enamine; hydroxylamine ethers generated cyclic products which showed in dimethylsulfoxide ring chain isomerism with the tautomers.
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Bardini, Carla, and Yu Chen. "Homomorphisms of two-dimensional linear groups over a ring of stable range one." Journal of Algebra 303, no. 1 (September 2006): 30–41. http://dx.doi.org/10.1016/j.jalgebra.2006.06.031.
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Sau, Samaresh Chandra, Pradip Kumar Hota, Swadhin K. Mandal, Michele Soleilhavoup, and Guy Bertrand. "Stable abnormal N-heterocyclic carbenes and their applications." Chemical Society Reviews 49, no. 4 (2020): 1233–52. http://dx.doi.org/10.1039/c9cs00866g.
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