A natural-product-inspired photonic logic gate based on photoinduced electron-transfer-generated dual-channel fluorescence

[structure: see text] Modified 1-benzylisoquinoline N-oxides can operate as molecular logic gates. The combination of dual-channel fluorescence emissions and the preferred interaction for selected chemical inputs allows one to design multifunction and self-reprogrammable molecular logic gates.     

Measurements of F2 and xF(nu)(3) - xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe Data in a Physics Model-Independent Way

We report on the extraction of the structure functions F2 and DeltaxF(3) = xF(nu)(3)-xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe differential cross sections. The extraction is performed in a physics model-independent (PMI) way. This first measurement of DeltaxF(3), which is useful in testing models of heavy charm production, is higher than current theoretical predictions. The ratio of the F2 (PMI) values measured in nu(mu) and mu scattering is in agreement (within 5%) with the predictions of next-to-leading-order parton distribution functions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data.     

Variational Evaluation of the HSSH FIR Transitions: The Anomalous K-Doubling

The roto-torsional energy levels of HSSH and DSSD up to J = 20 are evaluated variationally with a Hamiltonian expressed in terms of internal coordinates. The kinetic and potential parameters are derived from ab initio calculations with full optimization of the geometry. The calculated levels are employed for the determination of the centrifugal distortion constants. HSSH is a near-prolate symmetric rotor. The most stable C(2) conformer, calculated with MP4(SDQ)/cc-pVQZ, exhibits a 90.55 degrees dihedral angle. For J = 0, the lowest energies of HSSH and DSSD are 413.4876 cm(-1) (n = 1), 798.0304 cm(-1) (n = 2) and 1151.5773 cm(-1) (n = 3), and 304.3185 cm(-1) (n = 1), 594.2919 cm(-1) (n = 2), and 869.3508 cm(-1) (n = 3), respectively. For J = 60, the ab initio calculations allow the reproduction of the anomalous type-K doubling predicted with perturbation theory. Copyright 2000 Academic Press.     

Improved branching ratio measurement for the decay K(0)(L) --> &mgr;(+)&mgr;(-)

We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K(0)(L)-->&mgr;(+)&mgr;(-) with respect to the CP-violating mode K(0)(L)-->pi(+)pi(-). This experiment detected over 6200 candidate &mgr;(+)&mgr;(-) events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio gamma(K(0)(L)-->&mgr;(+)&mgr;(-))/gamma(K(0)(L)-->pi(+)pi(-)) = (3. 474+/-0.057)x10(-6) leads to a branching fraction B(K(0)(L)-->&mgr;(+)&mgr;(-)) = (7.18+/-0.17)x10(-9), which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3.     

Phosphoryl chloride induced ring contraction of 1,4-benzodiazepinones to chloromethylquinazolines

A ring contraction of 1,4-benzodiazepin-2-one to 2-chloromethylquinazoline in phosphoryl chloride is described. The intermediacy of an aziridinoquinazoline is proposed.     

Structural and electronic study of neutral,positive, and negative small rhodium clusters [Rhn,Rh, and Rh]

We have carried out a systematic study for the determination of the structure and the fundamental state of neutral and ionic small rhodium clusters [Rh_n, Rh, Rh (n = 5–10)] using ab initio Hartree‐Fock methods with a LANL2DZ basis set. A range of spin multiplicities is studied for each cluster. We present the bond lengths and angles and geometric configuration adopted for the clusters in its minimum energy conformation showing the differences when the clusters have different number of unpaired electrons. In addition, we report the vertical ionization potential and the adiabatic potential calculated by the Koopman's theorem. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2541–2547, 2010     

SPE and LC-MS/MS determination of 14 illicit drugs in surface waters from the Natural Park of L’Albufera (València, Spain)

A simple and robust method using solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 14 drugs of abuse and their metabolites (cocainics, amphetamine-like compounds, cannabinoids, and opiates) in surface waters has been developed. Seven SPE adsorbents (Oasis HLB, Oasis MCX, Oasis Wax, Supelselect HLB, Strata-X, Strata-XCW), amount of sorbent bed, water volume, and pH were investigated. The highest recoveries, as well as the simplest protocol, were obtained for Oasis HLB cartridges (6 mL/200 mg) using 250 mL of water. The proposed method was linear in a concentration range from 0.03–6 to 300–60,000 ng/L depending on the compound, with correlation coefficients higher than 0.998. Matrix effects have been studied in surface water samples, and several isotope-labeled internal standards have been evaluated as a way to compensate the signal suppression observed. Limits of detection (LODs) and quantification (LOQs) ranged from 0.01 to 1.54 ng/L and from 0.03 to 5.13 ng/L, respectively. Recoveries were 71–102% at the LOQ level and 77–104 at 50 ng/L. The intra-day and intermediate precisions were from 1% to 8% and from 2% to 11%, respectively. The present work reports for the first time the occurrence of drugs of abuse residues in surface water samples from the Natural Park of L’Albufera (Valencia, Spain). Codeine, cocaine, benzoylecgonine, ecgonine methylester, amphetamine, 3,4-methylendioxy methamphetamine, morphine, and methadone were quantified with median values of 11.10, 0.02, 5.59, 0.08, 0.21, 0.75 and 0.14 ng/L respectively, and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol was detected in one sample at levels <LOQ.     

Determination of multiresidue pesticides in green tea by using a modified QuEChERS extraction and ion-trap gas chromatography/mass spectrometry

The pesticide residues in exported and imported tea products must not exceed the maximum residue limits (MRLs) regulated by the import countries. Tea is a complex matrix that obfuscates the determination of pesticide residues. Many available methods for multiresidue pesticide analysis of tea are time-consuming and require many cleanup steps. The objective of this study was to develop a simple multiresidue method by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ion-trap GC/MS/MS, which can identify, confirm, and quantify pesticides in complex matrixes. A tea product was homogenized with water, and the pesticides were extracted with acetonitrile containing 1% acetic acid. The extract was subjected to centrifugation, initial cleanup with dispersive SPE (dSPE), solvent exchange, and final cleanup with dSPE. Diethyl-d10-parathion and triphenyl phosphate were used as the internal standard and surrogate, respectively. The final extract was injected into an ITQ 700 gas chromatograph/mass spectrometer. Quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient of > 0.9930 for the 22 pesticides selected for the study. The recoveries of the 22 pesticides ranged from 78 to 115%, except those for diazinon (130%) and malathion (122%), with an average RSD of 8.7%. The LOD values of all of the pesticides, except for terbufos, were below the MRLs set by the European Union and Japan.     

Evaluation of the performance of single‐walled carbon nanohorns in capillary electrophoresis

This paper describes for the first time the use of single‐walled carbon nanohorns (SWNHs) as pseudostationary and stationary phases for EKC and CEC, respectively, taking advantage of their characteristic features, such as conical‐end termination, formation of spherical assemblies dahlia‐flower like superstructure and easy functionalization. The use of SWNHs as pseudostationary phase for EKC required the study of their dispersion in different surfactants as well as their compatibility with the electrophoretic system. The carboxylation and subsequent immobilization of carboxylated SWNHs in fused‐silica capillary to obtain useful, reproducible and stable stationary phases for CEC has also been investigated, with promising results. The electrophoretic separations obtained for water‐soluble vitamins in both modalities (EKC and CEC) have been systematically compared with those obtained with single‐walled carbon nanotubes.