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1.
Omer Ozturk Steven N. MacEachern 《Annals of the Institute of Statistical Mathematics》2004,56(4):701-720
We develop a method of randomizing units to treatments that relies on subjective judgement or on possible coarse modeling
to produce restrictions on the randomization. The procedure thus fits within the general framework of ranked set sampling.
However, instead of selecting a single unit from each set for full measurement, all units within a set are used. The units
within a set are assigned to different treatments. Such an assignment translates the positive dependence among units within
a set into a reduction in variation of contrasting features of the treatments.
A test for treatment versus control comparison, with controlled familywise error rate, is developed along with the associated
confidence intervals. The new procedure is shown to be superior to corresponding procedures based on completely randomized
or ranked set sample designs. The superiority appears both in asymptotic relative efficiency and in power for finite sample
sizes. Importantly, this test does not rely on perfect rankings; rather, the information in the data on the quality of rankings
is exploited to maintain the level of the test when rankings are imperfect. The asymptotic relative efficiency of the test
is not affected by estimation of the quality of rankings, and the finite sample performance is only mildly affected. 相似文献
2.
Tetsuya Okuyama Masaru Nakayama Yoshitsugu Tomokiyo Omer Van Der Biest 《Microscopy and microanalysis》2002,8(1):11-15
Lattice strains around a platelet oxygen precipitate in Si wafer is studied by energy filtering convergent-beam electron diffraction (CBED) and calculations based on the finite element method (FEM). Local lattice strains are measured from CBD patterns obtained with a probe size less than 2 nm in a specimen thicker than 450 nm. Strains measured are compressive along a direction normal to a plate of the precipitation and tensile along a direction parallel to the plate. Two-dimensional stress fields near the precipitate are obtained with FEM computer analyses by fitting the measured strains. It appears that shear stresses are concentrated at the end of the precipitate edge and the maximum shear stress at an interface between the precipitate and the Si-matrix is 1.9 GPa. It is demonstrated that a combination of the energy filtering CBED and FEM is very useful for the study of local strains near interfaces in semiconductor devices, in particular for the study of stress fields that are too steep for application of the conventional CBED technique. 相似文献
3.
Chemical effects on Kβ/Kα X-ray intensity ratios for some Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn compounds are studied experimentally. The X-ray spectra were measured by using a Si (Li) solid state detector with high resolution. The vacancies were produced by heavily filtered 241Am gamma rays. It is found that the Kβ/Kα X-ray intensity ratios measured with compounds deviated up to 43% from the corresponding values of the pure elements. The values for pure elements are compared with the other experimental and with theoretical values. 相似文献
4.
Turan K. Yazicilar Omer Andac Yunus Bekdemir Halil Kutuk Veysel T. Yilmaz William T. A. Harrison 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m21-m22
The title compound, alternatively named sodium 6‐nitro‐3H‐1,2,3‐benzoxathiazole 2,2‐dioxide monohydrate, Na+·C6H3N2O5S?·H2O, consists of chains of NaO7 units, with the seven donor‐O atoms coming from two water molecules and five p‐nitrobenzoxasulfamate anions. The seven‐coordinate geometry around the Na+ ion is described as monocapped trigonal prismatic, but with a large distortion from ideal geometry. Each triangular face is defined by one O atom each from a water molecule, a nitro group and a sulfonyl group. An O atom from a sulfonyl group caps one of the square faces of the trigonal prism in an unsymmetrical fashion. The water molecules and one sulfonyl O atom are involved in bridging adjacent units, as is the nitro group of the anion. The sulfamate ions adopt an antiparallel alignment between the NaO7 units and are connected to each other by C—H?O and π–π interactions. The three‐dimensional crystal structure is stabilized by a network of strong O—H?N hydrogen bonds. 相似文献
5.
Yildiray Topcu Omer Andac Veysel T. Yilmaz William T. A. Harrison 《Journal of Molecular Structure》2002,610(1-3):99-103
The synthesis, molecular and crystal structure of bis(triethanolamine)Mn(II) saccharinate, [Mn(tea)2](sac)2 are reported. The configuration of the tea ligands results in an unusual example of coordination number seven for the Mn(II) ion. The two triethanolamine (tea) ligands coordinate to the Mn(II) ion forming a monocapped trigonal prism geometry, in which one of the tea ligands behaves as a tridentate ligand, while the other one acts as a tetradentate donor. The free and coordinated hydroxyl hydrogens of the tea ligands are involved in hydrogen bonding with the amine nitrogen, carbonyl and sulfonyl oxygens of the neighbouring sac ions to form a three-dimensional infinite network. A weak π–π interaction between the phenyl rings of the sac ions also occurs. 相似文献
6.
Ibrahim Isildak Murat Yolcu Omer Isildak Nadir Demirel Giray Topal Halil Hosgoren 《Mikrochimica acta》2004,144(1-3):177-181
Two diaza-crown ether compounds were synthesized and evaluated as Ag+-selective carriers in polyvinylchloride (PVC) membrane electrodes of solid-state type. The all-solid-state PVC membrane electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 exhibited a super-Nernstian response (75±10mV per decade) over the concentration range of 1×10–1 to 7×10–6M of Ag+ ion and a detection limit of 3×10–6M, at a wide range of pH (pH 4–7). The response time of the electrode was fast (less than 10s), and it can be used for three months without any significant deviation in potential. The proposed all-solid-state PVC membrane electrodes revealed high selectivity toward Ag+ ion with respect to alkali, alkaline earth, heavy and transition metal ions. A flow-through cell of all-solid-state PVC membrane Ag+-selective electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 has also been prepared and applied for flow-injection analysis of Ag+ ion in solution. 相似文献
7.
Veysel T. Yilmaz Serkan Guney Omer Andac William T. A. Harrison 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):m427-m430
The title complexes [M(sac)2(mpy)2] [sac is saccharinate (C7H4NO3S) and mpy is 2‐pyridylmethanol (C6H7NO)], with M = ZnII and CdII, are isostructural and consist of neutral molecules. The ZnII or CdII cations are octahedrally coordinated by the two neutral mpy and two anionic sac ligands. The mpy ligand acts as a bidentate donor through the amine N and hydroxyl O atoms. The sac ligands exhibit an ambidentate coordination behaviour; one is N‐coordinated and the other is O‐coordinated within the same coordination octahedron. The crystal packing is determined by C—H?O‐type hydrogen bonding, as well as by weak py–py and sac–sac aromatic π–π‐stacking interactions. 相似文献
8.
Molybdenum(VI) oxide, ammonium molybdate and molybdic acid reacted in molten sodium nitrite—potassium nitrite eutectic to form orthomolybdate, nitrogen dioxide and nitric oxide (with nitrate as a secondary product), a more polymerised polymolybdate being formed as an intermediate product. Tungsten(VI) oxide reacted similarly but less rapidly. Molybdenum and tungsten metals reacted to form the orthoxyanion and nitrogen, the latter metal reacting considerably faster and forming smaller amounts of nitric oxide and nitrous oxide. Reaction temperatures and stoichiometries are given and reaction pathways suggested. 相似文献
9.
Muhammad Zaman Muhammad Hammad Butt Waqar Siddique Muhammad Omer Iqbal Naveed Nisar Asma Mumtaz Hafiza Yusra Nazeer Abdulrahman Alshammari Muhammad Shahid Riaz 《Molecules (Basel, Switzerland)》2022,27(23)
Tenofovir alafenamide (TAF) is an antiretroviral (ARV) drug that is used for the management and prevention of human immunodeficiency virus (HIV). The clinical availability of ARV delivery systems that provide long-lasting protection against HIV transmission is lacking. There is a dire need to formulate nanocarrier systems that can help in revolutionizing the way to fight against HIV/AIDS. Here, we aimed to synthesize a polymer using chitosan and polyethylene glycol (PEG) by the PEGylation of chitosan at the hydroxyl group. After successful modification and confirmation by FTIR, XRD, and SEM, TAF-loaded PEGylated chitosan nanoparticles were prepared and analyzed for their particle size, zeta potential, morphology, crystallinity, chemical interactions, entrapment efficacy, drug loading, in vitro drug release, and release kinetic modeling. The fabricated nanoparticles were found to be in a nanosized range (219.6 nm), with ~90% entrapment efficacy, ~14% drug loading, and a spherical uniform distribution. The FTIR analysis confirmed the successful synthesis of PEGylated chitosan and nanoparticles. The in vitro analysis showed ~60% of the drug was released from the PEGylated polymeric reservoir system within 48 h at pH 7.4. The drug release kinetics were depicted by the Korsmeyer–Peppas release model with thermodynamically nonspontaneous drug release. Conclusively, PEGylated chitosan has the potential to deliver TAF from a nanocarrier system, and in the future, cytotoxicity and in vivo studies can be performed to further authenticate the synthesized polymer. 相似文献
10.
New tandospirone analogues containing a 1-[3-(trifluoromethyl)phenyl]piperazine (TFMPP) moiety have been synthesized by hydroarylation reactions with Pd(OAc)2. The perhydroisoindole derivatives were obtained by the reaction of reduced starting material with aryl-(heteroaryl) iodides under the same conditions. Spiro-1,3-indandionolylpyrrolidine derivatives having an array of stereocenters are reported. 相似文献