Limit on nonlocality in any world in which communication complexity is not trivial

Bell proved that quantum entanglement enables two spacelike separated parties to exhibit classically impossible correlations. Even though these correlations are stronger than anything classically achievable, they cannot be harnessed to make instantaneous (faster than light) communication possible. Yet, Popescu and Rohrlich have shown that even stronger correlations can be defined, under which instantaneous communication remains impossible. This raises the question: Why are the correlations achievable by quantum mechanics not maximal among those that preserve causality? We give a partial answer to this question by showing that slightly stronger correlations would result in a world in which communication complexity becomes trivial.     

Negative and positive secondary ion mass spectra of organic acids

Organic compounds can be ionized by sputtering the solid sample. The resulting negative and positive secondary ions provide mass spectra which characterize both the molecular weights and the structures of the compounds. Ionization occurs either by direct ejection of charged species from the solid into vacuum or by electron or proton transfer. The sputtered secondary ions dissociate unimolecularly to give fragment ions. These reactions are identical to those which occur when the secondary ions are independently generated by chemical ionization, selected by mass and dissociated in a high energy gas phase collision. The negative ion SIMS spectra show molecular ions (M^?.) or (M-H)^? ions as the dominant high mass species together with fragments due to decarboxylation, dehydration and losses of other simple molecules. Stronger acids show larger (M-H)^?/M^?.abundance ratios. The positive ion spectra are complementary and also useful in characterizing molecular structures. Attachment of cations to organic molecules (cationization) occurs much more readily than anion attachment and this makes negative SIMS spectra simpler than these positive ion counterparts.     

Dissolution kinetics of K-alum crystals as judged from the measurements of surface undersaturations

The normal dissolution rates, the slopes and the average velocities of dissolution steps of etch pits on the (111) face of a K-alum crystal, originating from dislocations with Burgers vector 110, were measured in relation to the surface undersaturations. From the mutual relations, it was shown that the dissolution was controlled by both diffusion and surface kinetic processes, although the contribution of the latter process was smaller than in the case of growth. It was also demonstrated that the normal dissolution rate was always larger than the growth rate. This is attributed to the fact that the slopes of growth hillocks are invariably smaller than those of etch pits.     

Particle packed columns and monolithic columns in high-performance liquid chromatography-comparison and critical appraisal

The review highlights the fundamentals and the most prominent achievements in the field of high-performance liquid chromatography (HPLC) column development over a period of nearly 50 years. After a short introduction on the structure and function of HPLC columns, the first part treats the major steps and processes in the manufacture of a particle packed column: synthesis and control of particle morphology, sizing and size analysis, packing procedures and performance characterization. The next section is devoted to three subjects, which reflect the recent development and the main future directions of packed columns: minimum particle size of packing, totally porous vs. core/shell particles and column miniaturization. In the last section an analysis is given on an alternative to packed columns-monolithic columns, which have gained considerable attraction. The challenges are: improved packing design based on modeling and simulation for targeted applications, and enhanced robustness and reproducibility of monolithic columns. In the field of miniaturization, particularly in chip-based nano-LC systems, monoliths offer a great potential for the separation of complex mixtures e.g. in life science.     

Quantitative determination of BMS-378806 in human plasma and urine by high-performance liquid chromatography/tandem mass spectrometry

BMS-378806 is a human immunodeficiency virus (HIV) entry inhibitor that is being developed for the oral treatment of HIV infection. Human plasma and urine LC/MS/ MS methods have been developed and validated for the quantitation of BMS-378806. For human plasma method, methyl t-butyl ether was used to extract BMS-378806 from plasma in a 96-well format, and the organic layers were dried down and then reconstituted for the injection, while a dilute-and-shoot approach was used for human urine method in a 96-well format. Chromatographic separation was achieved isocratically on a Phenomenex C18 (2) Luna column (2 x 50 mm2, 5 microm). The mobile phase contained 60:40 v/v of 0.1% formic acid in water and ACN. Detection was by positive ion electrospray MS/MS. The standard curves ranged from 1.25 to 1000 ng/mL for the plasma assay and from 10 to 5000 ng/mL for the urine assay. The curves were fitted to a 1/x2 weighted quadratic regression model for both methods. The validation results demonstrated that both methods had satisfactory precision and accuracy across the calibration ranges. The methods were applied to the analysis of human plasma and urine samples from a single ascending dose clinical study to assess the pharmacokinetics of the drug. The pharmacokinetic analysis results indicated the absorption and disposition of the drug was rapid. The systemic exposure of BMS-378806 was generally dose proportional among the doses from 100 to 1200 mg, but not dose proportional to 1600 mg. There were modest increases in the systemic exposure when the drug was given with food or given as a solution formulation. Renal excretion was not a substantial elimination pathway of the drug. BMS378806 was safe and well tolerated over a dose range of 100-1600 mg administered as a single oral dose.     

The application of size exclusion chromatography to the analysis of biopolymers

High performance size exclusion chromatography (HPSEC), employing microparticulate, hydrophilic, surface-modified silicas or hydrophilic, cross-linked, organic polymers and buffered eluents, is an effective means of separating native and denatured proteins of molecular weights in the 10 000–500 000 range. HPSEC can be further used for molecular weight identification, and the fractionation and isolation of proteins.