89 research outputs found
Runge-Kutta and Block by Block Methods to Solve Non- Linear Volterra Integral Equation Of The Second Kind
In this paper, we discussedRunge-Kutta method (R.KM) and Block-by-Block method (B by BM) for used to solve (NVIE) of the second kind with continuous kernel. Numerical examples are presented and results are compared with the analytical solution to demonstrate the validity and applicability of this methods
Dicarbonyldichlorido(N,N,N′,N′-tetramethylethylenediamine)ruthenium(II)
In the title compound, [RuCl2(C6H16N2)(CO)2], the geometry around the RuII atom is a distorted RuC2N2Cl2 octahedron, with pairs of C and Cl atoms trans to each other and the N atoms of the bidentate ligand in a cis conformation. The five-membered chelate ring is puckered on the C—C bond
Water-stable zirconium-based metal-organic framework material with high-surface area and gas-storage capacities.
We designed, synthesized, and characterized a new Zr-based metal-organic framework material, NU-1100, with a pore volume of 1.53 ccg(-1) and Brunauer-Emmett-Teller (BET) surface area of 4020 m(2) g(-1) ; to our knowledge, currently the highest published for Zr-based MOFs. CH4 /CO2 /H2 adsorption isotherms were obtained over a broad range of pressures and temperatures and are in excellent agreement with the computational predictions. The total hydrogen adsorption at 65 bar and 77 K is 0.092 g g(-1) , which corresponds to 43 g L(-1) . The volumetric and gravimetric methane-storage capacities at 65 bar and 298 K are approximately 180 vSTP /v and 0.27 g g(-1) , respectively.OKF, JTH and RQS thank DOE ARPA-E and the Stanford Global Climate and Energy Project for support of work relevant to methane and CO2, respectively. TY acknowledges support by the U. S. Department of Energy through BES Grant No. DE-FG02-08ER46522. WB acknowledges support from the Foundation for Polish Science through the “Kolumb” Program. DFJ acknowledges the Royal Society (UK) for a University Research Fellowship. This material is based upon work supported by the National Science Foundation (grant CHE-1048773).This is the accepted manuscript. The final version is available as 'Water-Stable Zirconium-Based Metal–Organic Framework Material with High-Surface Area and Gas-Storage Capacities' from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/chem.201402895/abstract
Using Orthogonal Locality Preserving Projections to Find Dominant Features for Classifying Retinal Blood Vessels
Long-term Impact of Mode of Delivery on Stress Urinary Incontinence and Urgency Urinary Incontinence: A Systematic Review and Meta-analysis
Context: Stress urinary incontinence (SUI) and urgency urinary incontinence (UUI) are associated with physical and psychological morbidity, and large societal costs. The long-term effects of delivery modes on each kind of incontinence remain uncertain.Objective: To investigate the long-term impact of delivery mode on SUI and UUI.Evidence acquisition: We searched Medline, Scopus, CINAHL, and relevant major conference abstracts up to October 31, 2014, including any observational study with adjusted analyses or any randomized trial addressing the association between delivery mode and SUI or UUI >= 1 yr after delivery. Two reviewers extracted data, including incidence/prevalence of SUI and UUI by delivery modes, and assessed risk of bias.Evidence synthesis: Pooled estimates from 15 eligible studies demonstrated an increased risk of SUI after vaginal delivery versus cesarean section (adjusted odds ratio [aOR]: 1.85; 95% confidence interval [CI], 1.56-2.19; I-2 = 57%; risk difference: 8.2%). Metaregression demonstrated a larger effect of vaginal delivery among younger women (p = 0.005). Four studies suggested no difference in the risk of SUI between spontaneous vaginal and instrumental delivery (aOR: 1.11; 95% CI, 0.84-1.45; I-2 = 50%). Eight studies suggested an elevated risk of UUI after vaginal delivery versus cesarean section (aOR: 1.30; 95% CI, 1.02-1.65; I-2 = 37%; risk difference: 2.6%).Conclusions: Compared with cesarean section, vaginal delivery is associated with an almost twofold increase in the risk of long-term SUI, with an absolute increase of 8%, and an effect that is largest in younger women. There is also an increased risk of UUI, with an absolute increase of approximately 3%.Patient summary: In this systematic review we looked for the long-term effects of childbirth on urinary leakage. We found that vaginal delivery is associated with an almost twofold increase in the risk of developing leakage with exertion, compared with cesarean section, with a smaller effect on leakage in association with urgency. (C) 2016 European Association of Urology. Published by Elsevier B.V
Structures of tetrasilylmethane derivatives (XMe2Si)2C(SiMe3)2 (X = H, Cl, Br) in the gas phase, and their dynamic structures in solution
The structures of the molecules (XMe2Si)2C(SiMe3)2, where X = H, Cl, Br, have been determined by gas electron diffraction (GED) using the SARACEN method of restraints, with all analogues existing in the gas phase as mixtures of C1- and C2-symmetric conformers. Variable temperature 1H and 29Si solution-phase NMR studies, as well as 13C NMR and 1H/29Si NMR shift correlation and 1H NMR saturation transfer experiments for the chlorine and bromine analogues, are reported. At low temperatures in solution there appear to be two C1 conformers and two C2 conformers, agreeing with the isolated-molecule calculations used to guide the electron diffraction refinements. For (HMe2Si)2C(SiMe3)2 the calculations indicated six conformers close in energy, and these were modeled in the GED refinement
The geometry of SiOCN and SiNCO linkages. The crystal structures of (Me3Si)2(Ph2MeSi)CSiMe2OCN and (PhMe2Si)3CSiMe2NCO
Single crystal X-ray diffraction studies have been carried out on the title compounds (in the case of the cyanate as its methylcyclohexane solvate). The geometry of the SiNCO fragment in the isocyanate (PhMe2Si)2CSiMe2NCO (<SiNC = 155.7(5), <NCO = 175.9(7)°, d(Si-N) = 1.739(5), d(N-C) = 1.135(8), d(C-C) 1.174(8) Å) is very similar to that in the much less crowded compounds H3SiNCO and ClCH2Me2SiNCO, but in all three compounds the Si-N-C angle of 180° in H3SiNCO is Me3SiNCO. In the light of the results the validity of recent calculations indicating and Si-N-C angle of 180° in H3SiNCO is questioned. In the case of the cyanate (Me3Si)2(Ph2MeSi)CSiMe2OCN, disorder results in considerable uncertainty in the geometry of the SiOCN linkage, but the values for the O-C-N and Si-O-C angles, 175(1)° and ca. 124 ± 6°, respectively, are consistent with those predicted by the corresponding calculations on H3SiOCN
A versatile bulky bidentate ligand for both main group and transition metals. Derivatives of lithium potassium magnesium chromium manganese and cobalt containing the C(SiMe3)2(SiMe2C5H4N-2)
The compound HC(SiMe3)2(SiMe2C5H4N-2), 1, reacts with methyllithium in THF to give a good yield of the lithium derivative which has been isolated as a molecular THF adduct 2. This reacts (a) with KOtBu to give 3, which crystallizes in a solvent-free ionic lattice, (b) with MgBr2 to give the Grignard reagent 4, and (c) with CrCl2 to give Cr{C(SiMe3)2(SiMe2C5H4N-2)}2, 5, along with the halide-bridged Grignard reagent analogue 6, which crystallizes in a lattice containing alternate THF-free molecules (6a) and molecules (6b) with coordinated THF. The reactions of 2 with MnCl2 and CoBr2 give the halide-bridged ate complexes 7, and 8, respectively
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