BACKGROUND Absolute quantification of protein biomarkers such as serum apolipoprotein A1 by both immunoassays and LC-MS can provide misleading results. RESULTS Recombinant ApoA-1 internal standard was prepared using stable isotope labeling by amino acids in cell culture with [(13)C6(15)N2]-lysine and [(13)C9(15)N1]-tyrosine in human cells. A stable isotope dilution LC-MS method for serum ApoA...

Stable isotope ratios of carbon and nitrogen in bone have become increasingly frequent inclusions in archaeological reports over the past few decades. The majority of such studies has been done in North America, where the use of marine foods and the introduction of maize have been monitored. Similar questions have been addressed in Mesoamerica and South America. In Europe, stable isotope ratios...

We use twisted stable maps to answer the following question. Let E ⊂ P2 be a smooth cubic. How many rational degree d curves pass through a general points of E , have b specified tangencies with E and c unspecified tangencies, and pass through 3d − 1 − a − 2b − c general points of P2? The answer is given as a generalization of Kontsevich’s recursion. We also investigate more general enumerative...

We present new radial velocities for 306 bright (R < 16) galaxies in a 77 deg 2 region of the Shapley supercluster measured with the FLAIR-II spectrograph on the UK Schmidt Telescope. The galaxies we measured were uniformly distributed over the survey area in contrast to previous samples which were concentrated in several rich Abell clusters. Most of the galaxies (230) were members of the Shapl...

Many problems of theoretical and practical interest can be formulated as Constraint Satisfaction Problems (CSPs). Solving a general CSP is known to be NP-complete; however, distributed models may take advantage of dividing the problem into a set of simpler interconnected sub-problems which can be more easily solved. In this work, we present a distributed model for solving large-scale CSPs. Our ...

This review is intended principally to be a reasonably comprehensive bibliography. It covers papers by workers in stable isotope geochemistry in the United States that have been published or presented at national meetings since the last quadrennial report. The titles of the papers in the bibliography are in most cases indicative of the general content, so only the highlights are described below...

Picarro WS-CRDS-based analyzers are the first instruments to combine simple, turnkey operation with sensitivity and precision better than or equal to the IRMS (isotope ratio mass spectrometer) systems traditionally used in stable isotope labs. This opens the door for widespread exploitation of stable isotope studies in fields such as carbon/water cycle research, GHG (greenhouse gas) monitoring,...

abstract: â in this study, the change in the crystalline structure of gas hydrate was predicted for ternary mixture of methane-ethane-water. for this purpose, the tangent plane distance (tpd) minimization method was used. first, the calculations were performed for the binary mixtures of methane-water and ethane-water as the gas and liquid phases. the results show that for a binary mixture of th...

this study is aimed at identifying and comparing the factors impacting on happy, stable marriages lasting more than 20 years and the factors influencing divorcing couples. using purposeful sampling, the sampling process continued until theoretical saturation. the obtained data were analyzed on the basis of grounded theory. the results indicate that a journey toward a thriving or dissolving marr...