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We report herein a new approach, which combines fast nucleophilic addition of H2S to an aldehyde group and the subsequent intramolecular thiolysis of dinitrophenyl ether, and can be used to develop efficient and effective H2S probes.

Combining metal–anion coordination and π–π stacking interactions, a zinc complex of a novel anthracene-based cyclophane was designed to recognise adenine nucleoside polyphosphates. This complex was found to show selective fluorescence enhancement for ATP, ADP, AMP and PPi in neutral aqueous solution. Among them, ADP induced the largest fluorescence change to the complex, while ATP showed the strongest binding affinity to the complex. This property was used to sense ATP in the presence of excess amounts of other phosphates such as ADP, AMP, PPi and Pi.

Unlike oil exploitation, most behavior of coal mine exploitation is out of the government’s control in contemporary China, but this is not enough to admit that officials can be absent from the accountability for a coal mine accident. Existing literatures to this puzzle pay more emphasis on the collusion among provincial officials, substrate officials and coal mine owners, but these researches neglect the facts that not all accidents involve in the provincial officials’ accountability. In this research we proposed an argument to probe into the puzzle on the basis of the institution of authoritarian regime, we found that the right division of coal mine safety regulation and its strategic decentralization under hierarchy can not only maintain the one party dictatorship, it also can avoid the political risk in the public goods supply of the regime, Then the provincial officials might be objects of the accountability as the result of this institution of risk aversion.

Hydrolysis of racemic cis-2-arylcyclopropanecarbonitriles catalyzed by Rhodococcus sp. AJ270 whole cells proceeded enantioselectively to afford the corresponding amide and acid with enantiomeric excess higher than 99%.

Enantioselective biotransformations of racemic trans -2-arylcyclopropanecarbonitriles catalyzed by Rhodococcus sp. AJ270 cells proceeded efficiently to give good to excellent optical yields of (−)-(1 R ,2 R )-2-arylcyclopropanecarboxamides and (+)-(1 S ,2 S )-2-arylcyclopropanecarboxylic acids, which were converted into optically active cyclopropylmethylamine and cyclopropylamine derivatives upon reduction and the Curtius rearrangement.

In this paper, a visible light excitable ESIPT probe was developed, which was found to be a very promising colorimetric and fluorescent sensor for rapid and selective detection of hydrogen sulfide in aqueous solution. The sensing mechanism and the application of this probe for hydrogen sulfide detection in biological serum and in simulated wastewater samples were investigated.

Introducing hydrogen bond donors to a receptor was found to be an effective approach to improve both its selectivity and binding affinity for pyrophosphate in water. The crystal structure of Zn3–ADP complex showed the improvements come from the combination of H-bonding and metal coordination in a manner similar to many metalloenzymes.

A novel NBD-phenoxo-bridged dinuclear Zn(II) complex is found to be an effective colorimetric sensor for pyrophosphate (PPi) in pure aqueous solution over a wide pH range. This sensor shows high binding affinity (K(a)≈ 3 × 10(8) M(-1)) and high selectivity for PPi, and can be also used to assay the activity of pyrophosphatase in real time.

Effective fluorescent sensing of oxalate in water is significant but still remains a challenge. By using indicator-displacement assays, a readily available macrocyclic copper(II) complex was found to show a sensitive off-on fluorescent sensing for oxalate with high selectivity and high binding affinity (10(7) M(-1)) in water at neutral pH.

This paper studied the efficiency of the oilfield water injection system by using the water injection system theory, fluid mechanics theory, and graph theory and optimization design technology. According to the actual conditions, the paper established the mathematical model of Wuliwan oilfield pipe network. Based on the actual data of production, energy distribution of oilfield water injection system was analyzed. Making the unit energy consumption of water injection lowest as the goal, solves through this mathematical model obtain the optimized pumping plan, thus the reasonably distribution of flooding energy, the enhancement pipe network system efficiency, reduces the system energy consumption. It supplies one scientific support for the Wuliwan oilfield to improve the level of flooding system management.

Reversible addition fragmentation chain transfer (RAFT) synthesis and self-assembly of free-base porphyrin cored star polymers are reported. The polymerization, in the presence of a free-base porphyrin cored chain transfer agent (CTA-FBP), produced porphyrin star polymers with controlled molecular weights and narrow polydispersities for a number of monomers includingN,N-dimethylacrylamide (DMA) and styrene (St). Well-defined amphiphilic star block copolymers, P-(PS-PDMA)4and P-(PDMA-PS)4(P: porphyrin), were also prepared and used for self-assembly studies. In methanol, a selective solvent for PDMA, spherical micelles were observed for both block copolymers as characterized by TEM. UV-vis studies suggested star-like micelles were formed from P-(PS-PDMA)4, while P-(PDMA-PS)4aggregated into flower-like micelles. Spectrophotometric titrations indicated that the optical response of these two micelles to external ions was a function of micellar structures. These structure-related properties will be used for micelle studies and functional material development in the future.

Enantioselective biotransformations of racemic trans -2-arylcyclopropanecarbonitriles catalyzed by Rhodococcus sp. AJ270 cells proceeded efficiently to give good to excellent optical yields of (−)-(1 R ,2 R )-2-arylcyclopropanecarboxamides and (+)-(1 S ,2 S )-2-arylcyclopropanecarboxylic acids, which were converted into optically active cyclopropylmethylamine and cyclopropylamine derivatives upon reduction and the Curtius rearrangement.

To compare image quality and radiation dose estimates for coronary computed tomography angiography (CCTA) obtained with a prospectively gated transaxial (PGT) CT technique and a retrospectively gated helical (RGH) CT technique using a 256-slice multidetector CT (MDCT) scanner and establish an upper limit of heart rate to achieve reliable diagnostic image quality using PGT. 200 patients (135 males, 65 females) with suspected coronary artery disease (CAD) underwent CCTA on a 256-slice MDCT scanner. The PGT patients were enrolled prospectively from January to June, 2009. For each PGT patient, we found the paired ones in retrospective-gating patients database and randomly selected one patient in these match cases and built up the RGH group. Image quality for all coronary segments was assessed and compared between the two groups using a 4-point scale (1: non-diagnostic; 4: excellent). Effective radiation doses were also compared. The average heart rate ± standard deviation (HR ± SD) between the two groups was not significantly different (PGT: 64.6 ± 12.9 bpm, range 45-97 bpm; RGH: 66.7 ± 10.9 bpm, range 48-97 bpm, P = 0.22). A receiver-operating characteristic (ROC) analysis determined a cutoff HR of 75 bpm up to which diagnostic image quality could be achieved using the PGT technique (P0.001). There were no significant differences in assessable coronary segments between the two groups for HR ≤ 75 bpm (PGT: 99.9% [961 of 962 segments]; RGH: 99.8% [1038 of 1040 segments]; P = 1.0). At HR75 bpm, the performance of the PGT technique was affected, resulting in a moderate reduction of percentage assessable coronary segments using this approach (PGT: 95.5% [323 of 338 segments]; RGH: 98.5% [261 of 265 segments]; P = 0.04). The mean estimated effective radiation dose for the PGT group was 3.0 ± 0.7 mSv, representing reduction of 73% compared to that of the RGH group (11.1 ± 1.6 mSv) (P0.001). Prospectively-gated axial coronary computed tomography using a 256-slice multidetector CT scanner with a 270 ms tube rotation time enables a significant reduction in effective radiation dose while simultaneously providing image quality comparable to the retrospectively gated helical technique. Our experience demonstrates the applicability of this technique over a wider range of heart rates (up to 75 bpm) than previously reported.

Reactivities of five phosphonate esters each coordinated to a dinuclear Co(III) complex were investigated ([Co(2)(tacn)(2)(OH)(2){O(2)P(Me)OAr}](3+); tacn = 1,4,7-triazacyclononane; substituent = m-F, p-NO(2) (1a); p-NO(2) (1b); m-NO(2) (1c); p-Cl (1d); unsubstituted (1e)). Hydrolysis of the phosphonate esters in 1a to 1e is specific base catalyzed and takes place by intramolecular oxide attack on the bridging phosphonate. These data define a Brønsted beta(lg) of -1.12, considerably more negative than that of the hydrolysis of the uncomplexed phosphonates (-0.69). For 1b, the kinetic isotope effects in the leaving group are (18)k(lg) = 1.0228 and (15)k = 1.0014, at the nonbridging phosphoryl oxygens (18)k(nonbridge) = 0.9954, and at the nucleophilic oxygen(18)k(nuc) = 1.0105. The KIEs and the beta(lg) data point to a transition state for the alkaline hydrolysis of 1b that is similar to that of a phosphate monoester complex with the same leaving group, rather than the isoelectronic diester complex. The data from these model systems parallel the observation that in protein phosphatase-1, which has an active site that resembles the structures of these complexes, the catalyzed hydrolysis of aryl methylphosphonates and aryl phosphates are much more similar to one another than the uncomplexed hydrolysis reactions of the two substrates.

The isomerization of beta-glucose-1-phosphate (betaG1P) to beta-glucose-6-phosphate (G6P) catalyzed by beta-phosphoglucomutase (betaPGM) has been examined using steady- and presteady-state kinetic analysis. In the presence of low concentrations of beta-glucose-1,6-bisphosphate (betaG16BP), the reaction proceeds through a Ping Pong Bi Bi mechanism with substrate inhibition (kcat = 65 s(-1), K(betaG1P) = 15 microM, K(betaG16BP) = 0.7 microM, Ki = 122 microM). If alphaG16BP is used as a cofactor, more complex kinetic behavior is observed, but the nonlinear progress curves can be fit to reveal further catalytic parameters (kcat = 74 s(-1), K(betaG1P) = 15 microM, K(betaG16BP) = 0.8 microM, Ki = 122 microM, K(alphaG16BP) = 91 microM for productive binding, K(alphaG16BP) = 21 microM for unproductive binding). These data reveal that variations in the substrate structure affect transition-state affinity (approximately 140,000-fold in terms of rate acceleration) substantially more than ground-state binding (110-fold in terms of binding affinity). When fluoride and magnesium ions are present, time-dependent inhibition of the betaPGM is observed. The concentration dependence of the parameters obtained from fitting these progress curves shows that a betaG1P x MgF3(-) x betaPGM inhibitory complex is formed under the reaction conditions. The overall stability constant for this complex is approximately 2 x 10(-16) M(5) and suggests an affinity of the MgF3(-) moiety to this transition-state analogue (TSA) of < or = 70 nM. The detailed kinetic analysis shows how a special type of TSA that does not exist in solution is assembled in the active site of an enzyme. Further experiments show that under the conditions of previous structural studies, phosphorylated glucose only persists when bound to the enzyme as the TSA. The preference for TSA formation when fluoride is present, and the hydrolysis of substrates when it is not, rules out the formation of a stable pentavalent phosphorane intermediate in the active site of betaPGM.

In order to improve capability of passive measurements, a novel approach is presented, which increase the medium wave and long wave infrared radiant information in the traditional bearings-only measurements equation. We explain the proposed mathematics model and modified covariance extend kalman filter algorithm in much detail in the full paper. Then the proposed model is used to estimate the position and velocity of aerial target by its angular information and infrared radiant information. Finally we give a simulation example. The results show that the passive measurements model proposed by us not only relax restriction of airplane motion, but also enhance the pace and precision of location, which looks promising for making passive measurements of position and velocity of target.

We report the results of protein folding (2I9M, C34, N36, 2KES, 2KHK) by the method of accelerated molecular dynamics (aMD) at room temperature with the implicit solvent model. Starting from the linear structures, these proteins successfully fold to the native structure in a 100-ns aMD simulation. In contrast, they are failed under the traditional MD simulation in the same simulation time. Then we find that the lowest root mean square deviations of helix structures from the native structures are 0.36 A, 0.63 A, 0.52 A, 1.1 A and 0.78 A. What is more, native contacts, cluster and free energy analyses show that the results of the aMD method are in accordance with the experiment very well. All analyses show that the aMD can accelerate the simulation process, thus we may apply it to the field of computer aided drug designs.

Cu is the key material for both on-chip and inter-chip interconnections. It is the major interconnect material in packaging level, especially in through wafer electrical interconnection (TWEI). Barrier layer is necessary as Cu is easy to diffuse into Si, SiO 2 and other dielectrics. Comparing with traditional Ta and Ti based barrier layers, electroless plating NiMoP film has many advantages, such as seedless, low cost, lower resistivity, etc. Electroless plating NiMoP was investigated on SiO 2 /Si. The plating solution was made up in house. Nickel sulfate and sodium molybdate were the sources of nickel and molybdenum. The effects of [MoO 4 2-]/[Ni2+] on the deposition rate of NiMoP and the film composition, electricity property, surface morphology & crystal structure were investigated. The deposition rate of NiMoP would be stable when the ratio of [MoO 4 2-]/[Ni2+] is higher than 0.08. The atom percentage of Mo in NiMoP film increases with the increasing of [MoO 4 2-]/[Ni2+] initially and then reaches a saturation amount at about 10at%, while the concentration of P decreases with the increasing [MoO 4 2-]/[Ni2+]. The resistivity of NiMoP film can be as low as 70.2 ??cm. The optimized deposition condition for a low resistivity NiMoP barrier is with the pH value of 9.0-10.0, plating temperature in the range of 85-90°C and [MoO 4 2-]/[Ni2+] of around 0.043. With Auger analysis, the deposited NiMoP film can be the effective diffusion barrier layers after 400°C annealing. A demonstration of 3D interconnection with electroless NiMoP barrier layer has been fabricated.

A novel fabrication process for electroless plating NiMoP barrier layer on SiO2 was presented for 3D packaging with silicon vertical interconnects. The NiMoP film was deposited electrolessly by using a silane coupling agent as an adhesion and catalyzed layer. In addition, a potential NiMoP barrier/seed layer was successfully formed via electroless plating atop SiO2 after Pd activation. The composition and the electrical resisitivity of NiMoP were investigated by scanning electron microscope (SEM) and four-point probe. The barrier layer and seed layer functions of NiMoP were verified by direct Cu electroplating and Auger electron microscope (AES).

Through wafer via fabrication has been one of the key technologies for 3-D packaging and microsystem packaging. Four different through wafer via fabrication technologies and applications are reviewed, such as laser drilling, deep reactive ion etching (DRIE), photo assisted electro chemical etching (PAECE) and KOH etching. Especially, KOH etching is widely used in bulk micromachining of microelectromechanical system (MEMS) fabrication and featured with anisotropic etching of silicon. Through wafer via technology based on double-sided KOH etching is presented, which needs double-sided alignment exposure. A SiO/sub 2/ layer is deposited by PECVD for insulation layer and then TiW/Cu sputtering and Cu electroplating are used to deposit conductive layers. In order to reroute the metal layer of silicon wafer with vias, photosensitive dry film and liquid photoresist exposure are tested.

Biotransformations of differently configured 2,2-dimethyl-3-substitued-cyclopropanecarbonitriles were studied using a nitrile hydratase/amidase-containing Rhodococcus sp. AJ270 whole-cell catalyst under very mild conditions. Although all of the cis-3-aryl-2,2-dimethylcyclopropanecarbonitriles appeared inert toward the biocatalyst, a number of racemic trans-isomers efficiently underwent a highly enantioselective hydrolysis to produce (+)-(1R,3R)-3-aryl-2,2-dimethylcyclopropanecarboxylic acids and (-)-(1S,3S)-3-aryl-2,2-dimethylcyclopropanecarboxamides in high yields with excellent enantiomeric excesses in most cases. The overall enantioselectivity of the biotransformations of nitriles originated from the combined effects of 1R-enantioselective nitrile hydratase and amidase, with the later being a dominant factor. The influence of the substrates on both reaction efficiency and enantioselectivity was discussed in terms of steric and electronic effects. Coupled with chemical transformations, biotransformations of nitriles provided convenient syntheses of optically pure geminally dimethyl-substituted cyclopropanecarboxylic acids and amides, including chrysanthemic acids, in both enantiomeric forms.

Rhodococcus sp. AJ270, a powerful and versatile nitrile hydratase/amidase containing microbial whole-cell system, catalyzed the enantioselective hydrolysis of both racemic trans- and cis-2-arylcyclopropanecarbonitriles to afford the corresponding amides and acids with enantiomeric excesses as high as >99%. The reaction rate and enantioselectivity observed for both nitrile hydratase and amidase were also strongly dependent upon the nature of the substituent and substitution pattern on the benzene ring of the substrates. The application of and the advantages of biotransformation of nitriles were demonstrated by preparing (1S,2R)-2-phenylcyclopropylamine and (1R,2R)-2-phenylcyclopropylmethylamine through facile and straightforward chemical manipulations of (1S,2S)-2-phenylcyclopropanecarboxylic acid and (1R,2R)-2-phenylcyclopropanecarboxamide, respectively.

The pulsed laser facility for SEU sensitivity mapping is utilized to study the SEU sensitive regions of a 0.18 μm CMOS SRAM cell. Combined with the device layout micrograph, SEU sensitivity maps of the SRAM cell are obtained. TCAD simulation work is performed to examine the SEU sensitivity characteristics of the SRAM cell. The laser mapping experiment results are discussed and compared with the electron micrograph information of the SRAM cell and the TCAD simulation results. The results present that the test technique is reliable and of high mapping precision for the deep submicron technology device.

The catalysis of phosphoryl transfer by metal ions has been intensively studied in both biological and artificial systems, but the status of the transient pentacoordinate phosphoryl species (as transition state or intermediate) is the subject of considerable debate. We report that dinuclear metal ion complexes that incorporate second sphere hydrogen bond donors not only promote the cleavage of RNA fragments just as efficiently as the activated analogue HPNPP but also provide the first examples of metal ion catalyzed phosphate diester isomerization close to neutral pH. This observation implies that the reaction catalyzed by these complexes involves the formation of a phosphorane intermediate that is sufficiently long-lived to pseudorotate.

The activity of a Zn(II) complex of a tetradentate, tripodal ligand for catalyzing phosphodiester cleavage is enhanced 750-fold by introducing three hydrogen bond donors to the ligand. Inhibition studies show that the Zn-aqua complex is the kinetically active form and that it binds the transition state with a formal dissociation constant of 3 x 108 M-1. The effect of these ligand modifications on the transition-state affinity is comparable to the rate acceleration provided by the metal ion itself. Overall, this mononuclear complex is more active than the most reactive dinuclear Zn(II) complexes reported to date.

A simple and readily available mononuclear zinc complex, which appends two anthracene groups, was unexpectedly found to show high selectivity for ADP with a unique increased fluorescence response in neutral aqueous solution.

A robust and copper-free clicked quantum dot–DNA sensor for sensitive and ratiometric detection of specific DNA and protein targets at the pM level is reported., We report herein the successful preparation of a compact and functional CdSe–ZnS core–shell quantum dot (QD)–DNA conjugate via highly efficient copper-free “click chemistry” (CFCC) between a dihydro-lipoic acid–polyethylene glycol–azide (DHLA–PEG–N3) capped QD and a cyclooctyne modified DNA. This represents an excellent balance between the requirements of high sensitivity, robustness and specificity for the QD-FRET (Förster resonance energy transfer) based sensor as confirmed by a detailed FRET analysis on the QD–DNA conjugate, yielding a relatively short donor–acceptor distance of ∼5.8 nm. We show that this CFCC clicked QD–DNA conjugate is not only able to retain the native fluorescence quantum yield (QY) of the parent DHLA–PEG–N3 capped QD, but also well-suited for robust and specific biosensing; it can directly quantitate, at the pM level, both labelled and unlabelled complementary DNA probes with a good SNP (single-nucleotide polymorphism) discrimination ability in complex media, e.g. 10% human serum via target-binding induced FRET changes between the QD donor and the dye acceptor. Furthermore, this sensor has also been successfully exploited for the detection, at the pM level, of a specific protein target (thrombin) via the encoded anti-thrombin aptamer sequence in the QD–DNA conjugate.

A novel merocyanine-based chemodosimeter was developed to detect fluoride ions in aqueous solution. This chemodosimeter was found to be a highly selective and sensitive colorimetric and fluorescent sensor for fluoride, and moreover, it shows a fast response within a few minutes to fluoride, thus providing a new and very promising sensor for rapid detection of fluoride in aqueous solution.

Few methods currently exist for controlling vesicle-vesicle adhesion. We now report a new system, based upon a multivalent guest and an amphiphilic receptor with a photo-isomerisable anchor that can be incorporated into lipid vesicles of different sizes. Large unilamellar vesicles containing our receptor were found to aggregate upon addition of the multivalent guest, independently of photoswitching between the two conformations of the anchor. However, for giant vesicles immobilised on a platinum wire, guest-mediated adhesion only occurred upon photo-isomerisation of the anchor. This behaviour was attributed to the dynamics introduced into the system through the conformational changes caused by irradiation.

Introducing ligand based hydrogen bond donors to increase the activity of a mononuclear Zn(II) complex for catalysing phosphate ester cleavage can be a more effective strategy than making the dinuclear analogue.