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Background: Self-assessed health status (SAHS) and physical performance measures (in particular, walking speed) are strong predictors of health-related events. Nevertheless, the possible interaction between them in predicting major outcomes has not been clearly explored. Objective: The aim of the study is to evaluate the predictive and additive value for mortality of a SAHS measure and a walking speed test. Methods: Data are from 2,139 Mexican-Americans aged ≥65 years enrolled in the Hispanic Established Populations for Epidemiologic Studies of the Elderly, and followed for 5.8 years. At the baseline visit, participants were asked to answer to the question 'How is your health in general?' presented as a four-level Likert item (i.e., poor, fair, good, excellent). They were also asked to 'walk down and back as fast as it felt safe and comfortable' along an 8-ft track. Cox proportional hazard models, receiver operating characteristic (ROC) curve, and specificity/sensitivity analyses were performed to evaluate the predictive value of SAHS and walking speed for mortality. Results: The mean age of the sample was 72.1 years. Participants reporting 'poor' SAHS were more likely to die compared to those with 'excellent' SAHS, even after adjustment for potential confounders (HR 1.52, 95% CI 1.10-2.10). Similar results were obtained for participants with slow walking speed (<0.29 m/s; HR 1.68, 95% CI 1.27-2.24; reference group: walking speed ≥0.81 m/s). A statistically significant, but weak, correlation between SAHS and walking speed was observed (Pearson's r = 0.069, p = 0.001). No significant differences in areas under curves from ROC analyses were reported for the prediction of mortality when the SAHS and walking speed were tested (alone or in combination). Both tests presented high specificity (≥80%) for the prediction of mortality. Conclusion: SAHS and walking speed are not only significant and independent predictors of mortality in older Mexican-Americans, but also pre

Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using (31)p NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, P-31 NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.

Column-switching liquid chromatography followed by lowresolution ICPMS was evaluated as a tool for speciation analysis of metal-containing biomolecules. The strategy was applied on siderophores, strong iron chelators of low molecular weight (M-w < 1500). Prior to the LC-ICPMS analysis, reductive displacement of iron by gallium was performed using ascorbate as the reducing agent to increase the sensitivity. Different experimental conditions during the exchange reaction were tested using ferrichrysin and ferrichrome for evaluation. A reaction time of 30 min and a pH of 3.9 gave an exchange yield of 27 and 83% for ferrichrysin and ferrichrome, respectively. A gradient elution profile was also developed to separate gallium-chelated siderophores on a PGC column. Detection limits for standard solutions of ferrichrysin and ferrichrome in the low-nanomolar range were obtained by monitoring the gallium-69 isotope. The combined use of LC-ICPMS and LC-ESI-MS/MS was also evaluated as a tool to identify unknown metal complexes, here siderophores, in field soil solution samples.

Capillary electrophoresis (CE) has been combined with atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) for mass spectrometric (MS) detection. Separation conditions using potassium phosphate buffer and ammonium formate buffer have been compared for analysis of eleven pharmaceutical bases. The results showed improvements in separation efficiency and peak symmetry when phosphate buffer was used. The low flow in CE may enable utilization of these advances with MS detection. Compared with ESI, the APPI technique provided a cluster-free background. The enhanced signal-to-noise ratio in the total ion current (TIC) and the reduced spectral background indicated that the APPI process is less affected by non-volatile salts in the CE buffers. This results in a wider range of choice of CE buffers in CE/MS analysis when APPI is the ionization method.

Porous graphitic carbon has been successfully used for the separation of L-DOPA and four metabolites (dopamine, 3,4-dihydroxy-phenyl-acetic acid, homovanillic acid and 3-O-methyl-L-DOPA) and with a volatile mobile phase of relatively high percentage organic modifier (methanol-ammonium formate pH 2.9, 60∶40, v/v). The substances were analysed in plasma. Ultrafiltration was used to remove the proteins from the sample and a coupled column system to enrich and perform on-line sample clean up. Both precolumn and separation column of i. d. 0.2 mm were packed with porous graphitic carbon.

The processes that cause the failure of sheathless electrospray ionization (ESI) emitters, based on different kinds of gold coatings on fused-silica capillaries, are described and explained. The methods chosen for this study include electrochemical method, Addresses: Nyholm L, Uppsala Univ, Dept Analyt Chem, Box 531, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Analyt Chem, SE-75121 Uppsala, Sweden. Uppsala Univ, Dept Mat Sci, SE-75121 Uppsala, Sweden. Linkoping Univ, Dept Phys & Measurement Technol, Div Ap

The processes that cause the failure of sheathless electrospray ionization (ESI) emitters, based on different kinds of gold coatings on fused-silica capillaries, are described and explained. The methods chosen for this study include electrochemical methods, ICPMS analysis of the electrolytes used, SEM studies, and electrospray experiments. Generally, the failure occurs by loss of the conductive coating. It is shown that emitters with sputter-coated gold lose their coatings because of mechanical stress caused by the gas evolution accompanying water oxidation or reduction. Emitters with gold coatings on top of adhesion layers of chromium and nickel alloy withstand this mechanical stress and have excellent durability when operating as cathodes. When operating as anodes, the adhesion layer is electrochemically dissolved through the gold film, and the gold film then flakes off. It is shown that the conductive coating behaves as a cathode even in the positive electrospray mode when the magnitude of a superimposed reductive electrophoretic current exceeds that of the oxidative electrospray current. Fairy-dust coatings developed in our laboratory (see Barnidge, D. R., et al. Anal. Chem. 1999, 71, 4115-4118) by gluing gold dust onto the emitter, are unaffected by the mechanical stress due to gas evolution. When oxidized, the fairy-dust coatings show an increased surface roughness and decreased conductivities due to the formation of gold oxide. The resistance of this oxide layer is however negligible in comparison with that of the gas phase in ESI. Furthermore, since no flaking and only negligible electrochemical etching of gold was found, practically unlimited emitter lifetimes may be achieved with fairy-dust coatings.

When optimizing a capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS) system, consideration has to be given not only to the separation but also to the electrospray stability. Methods developed for CE/UV analysis of drugs and pe, Addresses: Markides K, Univ Uppsala, Dept Analyt Chem, POB 531, S-75121 Uppsala, Sweden. Univ Uppsala, Dept Analyt Chem, S-75121 Uppsala, Sweden. AstraZeneca R&D, S-15185 Sodertalje, Sweden.

The chemical and physical properties of the wood chips entering the Kraft pulping process are of high interest for many different reasons. The most important one is the possibility to establish an effective and dynamic forward process control. The same is, Addresses: Axrup L, Korsnas AB, SE-80181 Gavle, Sweden. Korsnas AB, SE-80181 Gavle, Sweden. Univ Uppsala, Dept Analyt Chem, S-75121 Uppsala, Sweden.

A strategy for the optimization of liquid chromatography (LC)-electrospray ionization mass spectrometry methods is proposed. The optimization aims at good chromatographic quality and a high signal-to-noise ratio for the analyte. The three-step strategy co, Addresses: Danielsson R, Univ Uppsala, Inst Chem, Dept Analyt Chem, Box 531, S-75121 Uppsala, Sweden. Univ Uppsala, Inst Chem, Dept Analyt Chem, S-75121 Uppsala, Sweden.

The spontaneous degradation of racemic o-carboranylalanine [3-(1,2-dicarbacloso-dodecaboran(12)-1-yl)-2-aminopropanoic acid], a carborane analogue of the amino acid phenylalanine, to the corresponding diastereomeric, racemic pairs of nido-carboranylalani, Addresses: Svantesson E, Uppsala Univ, Inst Chem, Dept Analyt Chem, Uppsala, Sweden. Uppsala Univ, Inst Chem, Dept Analyt Chem, Uppsala, Sweden. Uppsala Univ, Inst Chem, Dept Organ Chem, Uppsala, Sweden.

Some examples of recent development of the synthesis of compounds labelled with short-lived beta(+)-emitting radionuclides will be discussed with an emphasis on the importance of time in selecting a synthetic strategy. Furthermore the use of such labelle, Addresses: Langstrom B, Univ Uppsala, PET Ctr, S-75185 Uppsala, Sweden. Univ Uppsala, PET Ctr, S-75185 Uppsala, Sweden. Univ Uppsala, Dept Organ Chem, S-75185 Uppsala, Sweden. Univ Uppsala, Dept Analyt Chem, S-75185 Uppsala, Sweden.

Some examples of recent development of the synthesis of compounds labelled with short-lived beta(+)-emitting radionuclides will be discussed with an emphasis on the importance of time in selecting a synthetic strategy. Furthermore the use of such labelled compounds to monitor certain processes in areas within the held of analytical chemistry and in various applications in drug development will be presented.