A double-spike MC TIMS measurement procedure for low-amount Ca isotopic analysis of limited biological tissue samples.

The application of Ca isotopic analysis in biomedical studies has great potential to identify changes in Ca metabolism and bone metabolism. Reliable measurement of Ca isotope-amount ratios is challenging considering limited Ca amounts and significant procedural blank levels. In this study, Ca purification was performed using the DGA Resin, optimized for low procedural blanks and separation of Ca from matrix elements and isobaric interferences (Na, Mg, K, Ti, Fe, Ba), while maintaining quasi-quantitative recoveries which are sufficient since a 42Ca-48Ca double-spike (DS) was applied. Ca isotopic analysis was performed using multicollector thermal ionization mass spectrometry (MC TIMS). The obtained procedural Ca blank of ≤10 ng enables processing of limited Ca amounts down to 670 ng. Data reduction of the measured Ca isotope-amount ratios was performed using an in-house developed software solving the DS algorithm. Data quality was improved by extension of equilibration time of the sample-DS mixture and implementation of a normalization strategy for raw isotopic data. The reported δ(44Ca/40Ca)NIST SRM 915a of NIST SRM 915a processed as a sample was found to be 0.01 ‰ ± 0.08 ‰ (2 SD, n = 15). Ca isotope-amount ratios of the reference material NIST SRM 1400 (bone ash), NIST SRM 1486 (bone meal), GBW07601 (human hair), and IAPSO (seawater) were in good agreement within uncertainty with literature data. Novel data on additional reference materials for biological tissues (hair) is presented, which might indicate a potential fractionation of Ca incorporated into hair tissue when compared to the blood pool.

A fully automated simultaneous single-stage separation of Sr, Pb, and Nd using DGA Resin for the isotopic analysis of marine sediments.

A novel, fast and reliable sample preparation procedure for the simultaneous separation of Sr, Pb, and Nd has been developed for subsequent isotope ratio analysis of sediment digests. The method applying a fully automated, low-pressure chromatographic system separates all three analytes in a single-stage extraction step using self-packed columns filled with DGA Resin. The fully automated set-up allows the unattended processing of three isotopic systems from one sediment digest every 2 h, offering high sample throughput of up to 12 samples per day and reducing substantially laboratory manpower as compared to conventional manual methods. The developed separation method was validated using the marine sediment GBW-07313 as matrix-matched certified reference material and combines quantitative recoveries (>90% for Sr, >93% for Pb, and >91% for Nd) with low procedural blank levels following the sample separation (0.07 µg L-1 Sr, 0.03 µg L-1 Pb, and 0.57 µg L-1 Nd). The average δ values for Sr, Pb, and Nd of the separated reference standards were within the certified ranges (δ (87Sr/86Sr)NIST SRM 987 of -0.05(28) ‰, δ(208Pb/206Pb)NIST SRM 981 of -0.21(14) ‰, and δ(143Nd/144Nd)JNdi-1 of 0.00(7) ‰). The DGA Resin proved to be reusable for the separation of >10 sediment digests with no significant carry-over or memory effects, as well as no significant on-column fractionation of Sr, Pb, and Nd isotope ratios. Additional spike experiments of NIST SRM 987 with Pb, NIST SRM 981 with Sr, and JNdi-1 with Ce revealed no significant impact on the measured isotopic ratios, caused by potential small analyte peak overlaps during the separation of Sr and Pb, as well as Ce and Nd.

Long-term in vivo degradation behavior and near-implant distribution of resorbed elements for magnesium alloys WZ21 and ZX50.

UNLABELLED: We report on the long-term effects of degrading magnesium implants on bone tissue in a growing rat skeleton using continuous in vivo micro-Computed Tomography, histological staining and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Two different magnesium alloys-one rapidly degrading (ZX50) and one slowly degrading (WZ21)-were used to evaluate the bone response and distribution of released Mg and Y ions in the femur of male Sprague-Dawley rats. Regardless of whether the alloy degrades rapidly or slowly, we found that bone recovers restitutio ad integrum after complete degradation of the magnesium implant. The degradation of the Mg alloys generates a significant increase in Mg concentration in the cortical bone near the remaining implant parts, but the Mg accumulation disappears after the implant degrades completely. The degradation of the Y-containing alloy WZ21 leads to Y enrichment in adjacent bone tissues and in newly formed bone inside the medullary space. Locally high Y concentrations suggest migration not only of Y ions but also of Y-containing intermetallic particles. However, after the full degradation of the implant the Y-enrichment disappears almost completely. Hydrogen gas formation and ion release during implant degradation did not harm bone regeneration in our samples. STATEMENT OF SIGNIFICANCE: Magnesium is generally considered to be one of the most attractive base materials for biodegradable implants, and many magnesium alloys have been optimized to adjust implant degradation. Delayed degradation, however, generates prolonged presence in the organism with the risk of foreign body reactions. While most studies so far have only ranged from several weeks up to 12months, the present study provides data for complete implant degradation and bone regeneration until 24months, for two magnesium alloys (ZX50, WZ21) with different degradation characteristics. µCT monitoring, histological staining and LA-ICP-MS illustrate the distribution of the elements in the neighboring bony tissues during implant degradation, and reveal in particular high concentrations of the rare-earth element Yttrium.

Evaluation strategies for isotope ratio measurements of single particles by LA-MC-ICPMS.

Data evaluation is a crucial step when it comes to the determination of accurate and precise isotope ratios computed from transient signals measured by multi-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) coupled to, for example, laser ablation (LA). In the present study, the applicability of different data evaluation strategies (i.e. 'point-by-point', 'integration' and 'linear regression slope' method) for the computation of (235)U/(238)U isotope ratios measured in single particles by LA-MC-ICPMS was investigated. The analyzed uranium oxide particles (i.e. 9073-01-B, CRM U010 and NUSIMEP-7 test samples), having sizes down to the sub-micrometre range, are certified with respect to their (235)U/(238)U isotopic signature, which enabled evaluation of the applied strategies with respect to precision and accuracy. The different strategies were also compared with respect to their expanded uncertainties. Even though the 'point-by-point' method proved to be superior, the other methods are advantageous, as they take weighted signal intensities into account. For the first time, the use of a 'finite mixture model' is presented for the determination of an unknown number of different U isotopic compositions of single particles present on the same planchet. The model uses an algorithm that determines the number of isotopic signatures by attributing individual data points to computed clusters. The (235)U/(238)U isotope ratios are then determined by means of the slopes of linear regressions estimated for each cluster. The model was successfully applied for the accurate determination of different (235)U/(238)U isotope ratios of particles deposited on the NUSIMEP-7 test samples.

Preventive healthcare use among males with multiple sclerosis.

OBJECTIVES: To understand preventive healthcare use by males with multiple sclerosis (MS). STUDY DESIGN: Cross-sectional survey with secondary comparative data. METHODS: Primary survey data were collected from male veterans with MS (n = 1142) and compared with national surveillance data for a general veteran population (n = 31,500) and a general population (n = 68,357). Analyses compared use by group and identified variables associated with service use by male veterans with MS. RESULTS: More veterans with MS had a cholesterol check (93%) than the general veteran population (89%, P < 0.001) and the general population (78%, P < 0.001). More veterans with MS had received annual influenza vaccination (69%) than the general veteran population (58%, P < 0.001) and the general population (42%, P < 0.001). More veterans with MS (81%) had ever received pneumonia vaccination than the general veteran population (67%) and the general population (51%) (P < 0.001). Colon screening was received by 55% of veterans with MS, 49% of the general veteran population (P < 0.001), and 39% of the general population (P < 0.0001). Fewer veterans with MS (34%) had received a prostate-specific antigen (PSA) test and digital rectal examination than the general veteran population (46%, P < 0.001) and the general population (36%, not significant). In males with MS, variables independently associated with cholesterol checks were: white race [odds ratio (OR) = 3.75] and living in the south (OR = 1.95); variables independently associated with influenza vaccination were increased age (OR = 1.03) and being a non-smoker (OR = 0.55); increased age was independently associated with colon screening (OR = 1.02); variables independently associated with PSA testing were increased age (OR = 1.08) and being employed (OR = 3.31), and being unemployed was independently associated with pneumonia vaccination (OR = 0.16). CONCLUSIONS: More males with MS received several recommended preventive health services (e.g. cholesterol and colon screening, influenza and pneumonia vaccination) than males without MS. The Veterans Health Administration is meeting many prevention needs in males with MS, but there is room for improvement in areas such as reducing disparities in PSA screening and increasing respiratory vaccinations to meet national targets.

Determination of (90)Sr in soil samples using inductively coupled plasma mass spectrometry equipped with dynamic reaction cell (ICP-DRC-MS).

A rapid method is reported for the determination of (90)Sr in contaminated soil samples in the vicinity of the Chernobyl Nuclear Power Plant by ICP-DRC-MS. Sample preparation and measurement procedures focus on overcoming the isobaric interference of (90)Zr, which is present in soils at concentrations higher by more than six orders of magnitude than (90)Sr. Zirconium was separated from strontium in two steps to reduce the interference by (90)Zr(+) ions by a factor of more than 10(7): (i) by ion exchange using a Sr-specific resin and (ii) by reaction with oxygen as reaction gas in a dynamic reaction cell (DRC) of a quadrupole ICP-MS. The relative abundance sensitivity of the ICP-MS was studied systematically and the peak tailing originating from (88)Sr on mass 90 u was found to be about 3 x 10(-9). Detection limits of 4 fg g(-1) (0.02 Bq g(-1)) were achieved when measuring Sr solutions containing no Zr. In digested uncontaminated soil samples after matrix separation as well as in a solution of 5 microg g(-1) Sr and 50 ng g(-1) Zr a detection limit of 0.2 pg g(-1) soil (1 Bq g(-1) soil) was determined. (90)Sr concentrations in three soil samples collected in the vicinity of the Chernobyl Nuclear Power Plant were 4.66+/-0.27, 13.48+/-0.68 and 12.9+/-1.5 pg g(-1) corresponding to specific activities of 23.7+/-1.3, 68.6+/-3.5 and 65.6+/-7.8 Bq g(-1), respectively. The ICP-DRC-MS results were compared to the activities measured earlier by radiometry. Although the ICP-DRC-MS is inferior to commonly used radiometric methods with respect to the achievable minimum detectable activity it represents a time- and cost-effective alternative technique for fast monitoring of high-level (90)Sr contamination in environmental or nuclear industrial samples down to activities of about 1 Bq g(-1).

Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS.

This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, The Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH4NO3 extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%.

Adherence to immunosuppression: a prospective diary study.

Immunosuppression adherence among kidney transplant recipients is essential for graft survival. However, nonadherence is common, jeopardizing graft survival. Besides skipping dosages, little is known about other forms of medication nonadherence and their underlying reasons. This study sought to examine patients' extent of medication adherence over time and reasons for nonadherence. Thirty-nine new kidney transplant recipients were asked to complete a month-long medication-taking diary that included reporting medication nonadherence such as skipped medications, medications taken early or late, taking dosages greater or less than prescribed, and the reason for each occurrence of nonadherence. Of the 20 (51%) patients who completed the diary, 11 (55%) reported at least 1 form of nonadherence. Eleven patients reported taking their immunosuppression at least 1 hour later than the prescribed time, 1 patient reported skipping medication, but no patients reported changing the dosage on their own. Immunosuppression was taken on average 1.5 hours after the prescribed time. Of those patients who took their medications late, there were on average 3.1 occasions of taking it late. The most common reasons for this behavior included health care-related issues, followed by oversleeping, being away from home, work-related barriers, and forgetting. The majority of kidney transplant recipients took medications later than prescribed during 1 month. Future research should determine the clinical impact on graft function of late administration of immunosuppression. Interventions should be designed to better assist kidney recipients with taking medications on time, especially when they are away from home.

Fungal trehalose phosphorylase: kinetic mechanism, pH-dependence of the reaction and some structural properties of the enzyme from Schizophyllum commune.

Initial-velocity measurements for the phospholysis and synthesis of alpha,alpha-trehalose catalysed by trehalose phosphorylase from Schizophyllum commune and product and dead-end inhibitor studies show that this enzyme has an ordered Bi Bi kinetic mechanism, in which phosphate binds before alpha,alpha-trehalose, and alpha-D-glucose is released before alpha-D-glucose 1-phosphate. The free-energy profile for the enzymic reaction at physiological reactant concentrations displays its largest barriers for steps involved in reverse glucosyl transfer to D-glucose, and reveals the direction of phospholysis to be favoured thermodynamically. The pH dependence of kinetic parameters for all substrates and the dissociation constant of D-glucal, a competitive dead-end inhibitor against D-glucose (K(i)=0.3 mM at pH 6.6 and 30 degrees C), were determined. Maximum velocities and catalytic efficiencies for the forward and reverse reactions decrease at high and low pH, giving apparent pK values of 7.2--7.8 and 5.5--6.0 for two groups whose correct protonation state is required for catalysis. The pH dependences of k(cat)/K are interpreted in terms of monoanionic phosphate and alpha-D-glucose 1-phosphate being the substrates, and of the pK value seen at high pH corresponding to the phosphate group in solution or bound to the enzyme. The K(i) value for the inhibitor decreases outside the optimum pH range for catalysis, indicating that binding of D-glucal is tighter with incorrectly ionized forms of the complex between the enzyme and alpha-D-glucose 1-phosphate. Each molecule of trehalose phosphorylase contains one Mg(2+) that is non-dissociable in the presence of metal chelators. Measurements of the (26)Mg(2+)/(24)Mg(2+) ratio in the solvent and on the enzyme by using inductively coupled plasma MS show that exchange of metal ion between protein and solution does not occur at measurable rates. Tryptic peptide mass mapping reveals close structural similarity between trehalose phosphorylases from basidiomycete fungi.

Factors influencing participation of African American elders in exercise behavior.

This study was designed to examine factors influencing exercise behavior of older African American adults. Using the Transtheoretical Stages of Change Model and focus group methodology, 103 participants were assigned to gender and stage specific groups of 5 to 12 each. The focus group discussion guide was developed to explore the meaning of health and exercise, and factors that influence exercise behavior for each stage of the model. Responses varied by stage and gender. Men and women alike described health as the ability to remain active and participate in desired activities. The meaning of exercise varied, by stage, from the ability to perform household chores to engaging in aerobic activities. Many factors such as health, social support, efficacy, and motivation influenced the desire and ability to exercise. Women were more likely than men to identify family responsibility as a barrier to participation in exercise activities. Participants identified strategies to recruit and retain African American elders in exercise programs. Findings of the study have implications for health professionals designing exercise health promotion programs for older African American adults in community settings.

Sources of attrition in a church-based exercise program for older African-Americans.

Among 123 older African Americans recruited into a church-based exercise program, 43% had dropped out within four months. Compared to those who did not drop out, drop outs had lower levels of education, energy to do activities, energy to exercise, and self-ratings of health, all based on measures taken before the class. Over half of those who dropped out cited non-exercise related health problems, and 17% caregiver responsibilities. Of those who dropped out, half said they would continue to exercise and 32% said they intended to start within the next six months.

Concentrations of selected trace elements in human milk and in infant formulas determined by magnetic sector field inductively coupled plasma-mass spectrometry.

Magnetic sector field inductively coupled plasma-mass spectrometry (ICP-MS) was applied to the reliable determination of the 8 essential trace elements cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), selenium (Se), and vanadium (V) as well as the 7 nonessential and toxic elements silver (Ag), aluminum (Al), arsenic (As), gold (Au), platinum (Pt), scandium (Sc), and titanum (Ti) in 27 transitory and mature human milk samples and in 4 selected infant formulas. This advanced instrumentation can separate spectral overlaps from the analyte signal hampering significantly the determination of many trace elements by conventional ICP-MS. Moreover, superior detection limits in the picogram per liter range can be obtained with such magnetic sector field instruments. Therefore, this is the first study to report, the concentrations of the elements Ag, Au, Pt, Sc, Ti, and V in human milk and in infant formulas. Concentrations of Ag (median: 0.41 microg/L; range: < 0.13-42 microg/L) and Au (median: 0.29 microg/L; range 0.10-2.06 microg/L) showed large variations in human milk that might be associated with dental fillings and jewelry. Pt concentrations were very low with most of the samples below the method detection limit of 0.01 microg/L. Human milk concentrations of Co (median: 0.19 microg/L), Fe (380 microg/L), Mn (6.3 microg/L), Ni (0.79 microg/L), and Se (17 microg/L) were at the low end of the corresponding reference ranges. Concentrations of Cr (24.3 microg/L) in human milk were five times higher than the high end of the reference range. For Al (67 microg/L), As (6.7 microg/L), and V (0.18 microg/L), most of the samples had concentrations well within the reference ranges. All elemental concentrations in infant formulas (except for Cr) were approximately one order of magnitude higher than in human milk.

Comparative performance study of ICP mass spectrometers by means of U "isotopic measurements".

The performance of four commercially available ICPMS instruments of three different types was compared by means of uranium "isotopic measurements". Examined were two quadrupole sector (different generation, different manufacturer), one single detector double focusing magnetic sector and one multiple collector double focusing magnetic sector instruments. The same samples of the IRMM-072 series were used under routine conditions to measure the 233U/235U and the 233U/238U ratios which, in these samples, vary over almost three orders of magnitude from approximately 1 to approximately 2 x 10(-3). Within expanded (k = 2) uncertainties, good agreement was observed between the certified values and the data internally corrected for mass-discrimination effects. The magnitude of the evaluated uncertainties was different for each type of instrument. With the multiple collector instrument, expanded uncertainties varied from +/- 0.04% to +/- 0.24% for the 233U/235U ratio, and from +/- 0.08% to +/- 0.27% for the 233U/238U ratio. They were approximately 1 to 5 times larger with the single detector magnetic sector instrument, and approximately 10 to 25 times larger with both quadrupole sector instruments. With the multiple collector instrument, repeatability of the measurements seemed to be limited by the difficulty of correcting properly for instrumental background, whereas with the single detector magnetic sector instrument the counting statistics was the only limitation (on smallest ratios). Apparent mass-discrimination was clearly found to be larger but more reproducible (and hence easier to correct for) in the case of magnetic sector instruments than for both quadrupole sector instruments. If space charge effects were the main source of mass-discrimination for all instruments, these results are in contradiction with the hypothesis of the size of mass-discrimination decreasing with the acceleration voltage. With the single detector magnetic sector instrument in particular (when operated by changing the ion energy only), our results pointed at more than only one major source of mass-discrimination, with variable size depending on the ratios measured.

Simultaneous multi-element analysis of trace elements in soil samples by means of high-resolution inductively coupled plasma sector field mass spectrometry (SF-ICP-MS).

The potential of SF-ICP-MS for trace element analysis in complex environmental matrices such as soil solutions was investigated. Spectral interferences found in mass spectra of soil matrices are presented in detail. Furthermore, the influences of single components of the soil matrix on the signal intensity of selected elements were studied. Detection limits of different elements are presented with respect to the composition of the matrix. A fast and accurate method for quasi-simultaneous determination of Al, Si, P, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Sr, Mo, Cd, Sn, Hg and Pb in aqueous soil extracts was established.

SI-traceable certification of Cu, Cr, Cd and Pb in sediment and fly ash candidate reference materials.

Many fields in environmental analytical chemistry deal with very low limits and thresholds as set by governmental legislations or transnational regulations. The need for the accuracy, comparability and traceability of analytical measurements in environmental analytical chemistry has significantly increased and total uncertainties are even asked for by accreditation bodies of environmental laboratories. This paper addresses achieving these goals to guarantee accuracy, quality control, quality assurance or validation of a method by means of certified reference materials. The assessment of analytical results in certified reference materials must be as accurate as possible and every single step has to be fully evaluated. This paper presents the SI-traceable certification of Cu, Cr, Cd and Pb contents in geological and environmentally relevant matrices (three sediments and one fly ash sample). Certification was achieved using isotope dilution (ID) ICPMS as a primary method of measurement. In order to reduce significantly the number of analytical steps and intermediate samples a multiple spiking approach was developed. The full methodology is documented and total uncertainty budgets are calculated for all certified values. A non-element specific sample digestion process was optimised. All wet chemical digestion methods examined resulted in a more or less pronounced amount of precipitate. It is demonstrated that these precipitates originate mainly from secondary formation of fluorides (essentially CaF2) and that their formation takes place after isotopic equilibration. The contribution to the total uncertainty of the final values resulting from the formation of such precipitates was in general < 0.1% for all investigated elements. Other sources of uncertainty scrutinised included the moisture content determination, procedural blank determination, cross-contamination from the different spike materials, correction for spectral interferences, instrumental background and deadtime effects, as well as the use of either certified values or IUPAC data in the IDMS equation. The average elemental content in the sediment samples was 30-130 micrograms g-1 for Pb, 0.5-3 micrograms g-1 for Cd and 50-70 micrograms g-1 for Cu. Cr was measured in one sample and was about 60 micrograms g-1. The concentrations in the fly ash sample were up to 2 orders of magnitude higher. Expanded uncertainty for the investigated elements was about 3% (coverae factor k = 2) except for Cr, (measured by high resolution ICPMS), for which the expanded uncertainty was about 7% (k = 2).

Nursing home admission for African Americans with Alzheimer's disease.

BACKGROUND: For African Americans with Alzheimer's disease (AD), little is known about the time to, and risk factors for, nursing home admission (NHA). Using Consortium To Establish a Registry for Alzheimer's Disease (CERAD) data, this study provides information on NHA for African Americans. METHODS: This longitudinal study followed subjects (N=122) for as long as 7 years and used survival analysis methodology and variable values at baseline and at follow-up to identify NHA risk factors. Studied were sociodemographic variables, physical symptom and disease status variables, the Blessed Dementia Rating Scale (including subscores), the Clinical Dementia Rating (CDR), and the Mini-Mental State Examination. RESULTS: Only 25% of African Americans with AD were estimated to have had a NHA by 3.4 years (confidence interval 2.1, 5.4). Being unmarried resulted in a five times earlier NHA (p< .01), and each unit increase in the CDR resulted in a 74% earlier NHA (p<.01). In the absence of the CDR, limitation in activities of daily living was associated with earlier NHA (p<.05). CONCLUSIONS: Findings suggest that African Americans with AD spend a substantial time in the community prior to NHA, a longer time than observed in similar studies among whites. This raises public health and clinical concern that African Americans with AD may be residing in the community with substantial unmet needs, and that their caregivers have potentially high levels of burden. The independent associations with time to NHA observed here, although few in number, are consistent with other related research.

Age and the role of symptomatology in readiness to quit smoking.

To develop effective age-appropriate strategies for smoking cessation, it is important to understand factors associated with readiness to quit smoking. This article presents results from an analysis of the role of symptomatology in the decisions to quit smoking among three age groups (18-34, 35-54, and > or = 55 years) from a larger sample of smokers in a managed-care setting. Two measures of readiness to quit smoking were used: stages of change and intention to stop. Using ordinal logistic regression, we found that smokers in the middle and oldest age groups who had experienced at least three of five symptoms in the previous 2 weeks were more likely to be in higher stages of readiness. Regardless of age, smokers who attributed symptoms to smoking were more motivated to try to quit, whereas those who attributed symptoms to aging were less likely to intend to stop smoking. Findings from this study indicate a symptom-based approach to smoking cessation may be a useful strategy, especially in provider-based interventions.

Evidence of genocide 7000 BP--Neolithic paradigm and geo-climatic reality.

The early Neolithic fortified settlement of Schletz, Lower Austria is emerging as one of the most interesting sites of Linear Pottery culture excavation in Austria. In the course of systematic investigations carried out since 1983, a plethora of unexpected results have been obtained. Specifically, the human skeletal remains of 67 individuals have been found at the base of an oval trench system. Without exception, these remains are characterized by multiple traumatic lesions as well as carnivore gnaw marks. Demographic analysis presents the picture of the entire population of this early farming settlement having been extinguished. Further, the findings suggest that a genocide scenario may have been responsible for the final demise of this settlement. The age and sex distribution reveals a lack of young females, who are interpreted as having been abducted by aggressors. There is however no direct skeletal evidence of aggressors at the site; in fact, the uniformity of Strontium isotope ratios (HR-ICP-MS analysis) implies that all 67 individuals, who were left unburied for months, were indigenous. Supporting evidence of increased levels of inter-human aggression--possibly caused by a broad wave of migration--comes from other contemporary end linear pottery sites in Germany. Such findings are here discussed in the context of a dramatic geological event in the region of the Black Sea shelf at this time (7.550 BP), which led to the submergence of some 100.000 square kilometers of fertile land, and which might have been responsible for subsequent gradual population movements into the interior of Europe.

Time to nursing home admission for persons with Alzheimer's disease: the effect of health care system characteristics.

OBJECTIVE: To study the influence of state health care system characteristics on time to nursing home admission (NHA) for persons with Alzheimer's disease (AD). METHOD: Up to nine years of Consortium to Establish a Registry for Alzheimer's Disease (CERAD) data on 639 non-Latino White individuals were merged with longitudinal data from the 28 states in which the CERAD participants resided. The state variables reflected characteristics of each state's long-term care (LTC) system, including Medicaid LTC spending practices and the supply of LTC providers. Cox Proportional Hazards Models with time-varying covariates were used to evaluate the risk factors associated with time to NHA. RESULTS: There was differential influence of state variables by marital status. For unmarried non-Latino White persons with AD, a higher percentage of Medicaid LTC spending on home and community-based services (HCBS) was significantly associated with a longer time to NHA. For married persons, a greater number of home health agencies was associated with a longer time to NHA. Other associations also varied by marital status. CONCLUSION: Study findings support the utility of targeted continued expanded provision of HCBS by states and provide a basis for future research regarding the impact of changing state health care systems on LTC utilization for persons with AD.

Older adults and assistive devices: use, multiple-device use, and need.

Responses of older adults ( greater than 65 years) from the 1990 National Health Interview Survey and Assistive Device Supplement are analyzed to determine if selected demographic and health variables are associated with the use of assistive devices, multiple-device use, and the expressed need for such devices. Bivariate and multi-variate analyses show that, in general, poorer health is consistently associated with the use of assistive devices, multiple-device use, and expressed need. Demographic characteristics, however, vary in their relationships to assistive device use and need. Findings support the importance of considering multiple-device use and expressed need in studying assistive devices and older adults.