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In this study, SnO 2 /TiO 2 thin films are fabricated on SiO 2 /Si and Corning glass 1737 substrates using a R.F. magnetron sputtering process. The gas sensing properties of these films under an oxygen atmosphere with and without UV irradiation are carefully examined. The surface structure, morphology, optical transmission characteristics, and chemical compositions of the films are analyzed by atomic force microscopy, scanning electron microscopy and PL spectrometry. It is found that the oxygen sensitivity of the films deposited on Corning glass 1737 substrates is significantly lower than that of the films grown on SiO 2 /Si substrates. Therefore, the results suggest that SiO 2 /Si is an appropriate substrate material for oxygen gas sensors fabricated using thin SnO 2 /TiO 2 films.

The role of small heat shock proteins (sHsps) in the cellular chaperone system was examined with application of the feedback control technique widely used in engineering for stabilizing a specific system. We proposed a dynamic feedback control model for the thermotolerance machinery of sHsps from the system biology perspective, and for the first time verified that a system stabilization feedback control scheme is involved in the chaperone protecting activity under heat shock conditions. In the dynamic model of the chaperone protection system, the defense mechanism of sHsps is a sigmoid function and the influence of environment temperatures is a bell-shaped function. The close fit of the system dynamic behaviors to the kinetic data suggests that our system stabilization control model matches the protective mechanism conveyed by sHsps. Furthermore, the temporal changes of the unfolded intermediates and the sHsp-substrate complexes can be predicted by the proposed dynamic stabilization model, which are not easily measured in biochemical experiments. The identified feedback control matrix can be viewed as a biochemical interaction for measuring the protective activity of sHsps qualitatively and quantitatively. Our work introduces an innovative approach for analysis and detecting the kinetics of sHsps to resist protein aggregation from the system stabilization point of view.

The aim of this study is to find the effects of oxygen flow rate during manufacturing on the sensitivity of SnO 2 (tin oxide) thin films to ethanol (C 2 H 5 OH). In this study, an RF sputtering process was employed to fabricate the SnO 2 thin films. The SnO 2 was deposited on gold electrode silicon microchips. A target composed of SnO 2 doped with 1 at.% Li was used with a working pressure of 3 mTorr. The RF power was fixed at 150 W. The reaction gas was a mixture of argon and oxygen. The total flow rate was constant at 50 sccm with the O 2 /Ar ratio varying from 0.2 to 0.8. An annealing heat treatment was employed at 400 °C for 1 h to stabilize the properties of the films. The sensitivity of the film to ethanol was tested by placing the micro-reactor device on a hot plate, heated to 300 °C, and measuring the variation of electrical resistivity of the film with and without the presence of ethanol. The results show that an O 2 /Ar flow ratio of 0.2 produces films with the highest ethanol sensitivity. Before heat treating, the ethanol sensitivity was 126. After heat treating at 400 °C for 1 h, the sensitivity decreased to 104.

Flow cytometry is widely applied in the determination of nuclear DNA content and ploidy level in many organisms. However, a difficulty with flow cytometry is the method's intrinsic inability to tolerate large particles that associate with the isolated nuclei. A suspension of plant nuclei can often contain a high level of crystalline calcium oxalate, which blocks the fluidics system of the flow cytometer. We designed a cotton column and added polyvinylpyrrolidone-40 to the buffer to remove phenolic impurities and cytoplasmic compounds from plant nuclei, making the suspension suitable for flow cytometry. This simple and highly efficient protocol enables isolation of intact nuclei from plant tissues containing high levels of polysaccharides, calcium oxalate crystals and other metabolites. Our protocol resulted in the isolation of intact nuclei from mature orchid leaves. This method can be used on recalcitrant tissues and is particularly effective on plants containing calcium oxalate crystals.

TiO2 thin films when irradiated by UV light with a wavelength of 365 nm is investigated. The results indicate that the annealed samples have higher oxygen sensitivities than the as-deposited samples. The sensitivity of the non-annealed samples increases from 0.70 to 1.15 under UV irradiation, while the sensitivity of the annealed samples increases from 7.17 to 10.60. Therefore, it is clear that UV irradiation causes the sensitivity of the SnO2/TiO2 thin films to increase significantly. Finally, it is found that the oxygen sensitivity of the SnO2/TiO2 thin films increases as the SnO2/TiO2 ratio is reduced.

Two new linear tri-nickel(II) complexes with an infinite polymeric chain, [Ni 3 (μ 3 -dpa) 4 (C 4 O 4 Me)](BF4) 1 and [Ni 3 (μ 3 -dpa)4(N3)](PF6) 2, [dpa - = di(α-pyridyl)amido anion], have been synthesized and their structures were determined by X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group C 2/c, with a = 19.9078(3), b = 13.2986(2), c = 37.6622(5) A, β = 94.091(1)°, Z = 8. Compound 2 crystallizes in the monoclinic system, space group P 2 1 /n, with a = 13.323(4), b = 23.217(3), c = 17.528(5) A, β = 94.42(3)°, Z = 4. The two complexes are described as one-dimensional systems with the (C 4 O 4 Me) - , 1, or N 3 - , 2, serving as a μ-(1,3) bridged ligand at the two axial sites of each [Ni 3 (μ 3 -dpa) 4 ] 2 + fragment. The Ni-Ni distances of 2.400(1) and 2.402(1) in 1 and 2.389(2), 2.385(2) in 2 are obviously shorter than those of 2.4325(7), 2.4356(7) in the monomeric complex [Ni 3 (μ 3 -dpa) 4 (N 3 ) 2 ] 3. The magnetic properties of complexes 2 and 3 were studied by susceptibility measurements vs temperature. The Χ M vs T plots of both complexes show a strong antiferromagnetic behavior. The simulated J 1 3 values are -95 cm - 1 and -97 cm - 1 for 2 and 3, respectively.

Nuclear DNA contents were estimated by flow cytometry in 18 Phalaenopsis Blume species and Doritis pulcherrima Lindl. DNA amounts differed 6.07-fold, from 2.74 pg/diploid nuclear DNA content (2C) in P. sanderiana Rchb.f. to 16.61 pg/2C in P. parishii Rchb.f. Nuclear DNA contents of P. aphrodite Rchb.f. clones, W01-38 (2n = 2x = 38), W01-41 (2n = 3x = 57), and W01-22 (2n = 4x = 76), displayed a linear relationship with their chromosome numbers, indicating the accuracy of flow cytometry. Our results also suggest that the 2C-values of the Phalaenopsis sp. correlate with their chromosome sizes. The comparative analyses of DNA contents may provide information to molecular geneticists and systematists for genome analysis in Phalaenopsis. Endoreduplication was found in various tissues of P. equestris at different levels. The highest degree of endoreduplication in P. equestris was detected in leaves.

The linear pentanuclear chromium complexes [CrII5(μ5-tpda)4Cl2] (1), [CrII5(μ5-tpda)4(NCS)2] (2), [CrIIICrII4(μ5-tpda)4F2](BF4) (3), and [CrIIICrII4(μ5-tpda)4F(OTf)](OTf) (4), with four all-syn tri(α-pyridyl)diamido dianion (tpda2–) ligands, have been prepared and structurally characterized. Compounds 1 and 2 possess a delocalized Cr(II)–Cr(II)–Cr(II)–Cr(II)–Cr(II) five-centred metal–metal bond of order 1.5. In both 1 and 2 two values for CrII–CrII bond lengths are found both; the outer ones connected with axial ligands are 2.284(1) and 2.285(2) A, and the inner ones are 2.2405(8) and 2.246(1) A, for 1 and 2, respectively. When compound 1 reacts with 2 equiv. of AgBF4 or Ag(OTf), a oxidation reaction takes place and one of the terminal chromium(II) ions is oxidized to produce [CrIIICrII4(μ5-tpda)4F2]BF4 (3) or [CrIIICrII4(μ5-tpda)4F(OTf)](OTf) (4). Two short Cr–Cr distances [1.969(2) and 2.138(2) A for 3, 1.846(1) and 1.922(1) A for 4] are found, with the presence of two quadruple bonds among four adjacent CrII ions. The fifth CrIII ion, which is separated from the neighboring CrII ion by 2.487(2) A for 3 and 2.610(1) A for 4, is simply a square pyramidal unit with no metal–metal bonding interaction.

Three novel oligo-α-pyridylamino ligands, tripyridyldi-amine (H2tpda), tetrapyridyltriamine (H3teptra), pentapyridyltetramine (H4peptea) are synthesized; the crystal structures of their metal complexes with the all-anti configuration of the chelating ligands are reported.