Regional-scale assessment of soil salinity in the Red River Valley using multi-year MODIS EVI and NDVI.

The ability to inventory and map soil salinity at regional scales remains a significant challenge to scientists concerned with the salinization of agricultural soils throughout the world. Previous attempts to use satellite or aerial imagery to assess soil salinity have found limited success in part because of the inability of methods to isolate the effects of soil salinity on vegetative growth from other factors. This study evaluated the use of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in conjunction with directed soil sampling to assess and map soil salinity at a regional scale (i.e., 10-10(5) km(2)) in a parsimonious manner. Correlations with three soil salinity ground truth datasets differing in scale were made in Kittson County within the Red River Valley (RRV) of North Dakota and Minnesota, an area where soil salinity assessment is a top priority for the Natural Resource Conservation Service (NRCS). Multi-year MODIS imagery was used to mitigate the influence of temporally dynamic factors such as weather, pests, disease, and management influences. The average of the MODIS enhanced vegetation index (EVI) for a 7-yr period exhibited a strong relationship with soil salinity in all three datasets, and outperformed the normalized difference vegetation index (NDVI). One-third to one-half of the spatial variability in soil salinity could be captured by measuring average MODIS EVI and whether the land qualified for the Conservation Reserve Program (a USDA program that sets aside marginally productive land based on conservation principles). The approach has the practical simplicity to allow broad application in areas where limited resources are available for salinity assessment.

Design and applications of a home-built in situ FT-Raman spectroscopic cell.

In the field of heterogeneous catalysis, in situ spectroscopy is one of the topics with growing interest. The characterization of a catalyst under working conditions is essential to identify the catalytic active site and to study the relation between the surface structure of a catalyst and its catalytic performance. For the first time, the design of an in situ spectroscopic cell for FT-Raman is presented and its performance is demonstrated by monitoring the thermal conversion of as synthesized mesoporous titanium and by characterizing the molecular surface structure of the vanadium oxides grafted on MCM-48 after exposure to a probe molecule. The results in both cases indicate that the in situ FT-Raman cell is a promising technique for characterizing the molecular surface structure of catalyst materials.

Multicenter field trial on possible health effects of toluene. II. Cross-sectional evaluation of acute low-level exposure.

Data on possible acute effects of today's relevant low-level exposure to toluene are contradictory, and information on possible effects of exposure under occupational conditions is largely lacking. In a controlled, multi-center, blinded field trial, effects possibly associated with acute toluene exposure were evaluated in workers of 12 German rotogravure factories. Medical examinations (inquiries on subjective symptoms, and standard tests of psycho-physiological and psycho-motor functions) were performed on almost 1500 volunteers, of whom 1290 were toluene-exposed (1178 men and 112 women), and about 200 participants served as references (157 men and 37 women), but the main aim of the trial was to reveal dose-response relationships. All volunteers were of the morning work-shift (6 h exposure). Both individual ambient air concentrations (time-weighted average) during the work-shift, as well as blood toluene concentrations after the work-shift were measured. Therefore, the medical data could for the first time be correlated with the actual individual body burden (blood toluene level) at the time of testing. In order to largely exclude confounding by chronic toluene exposure, kinetic measurements as well as the psycho-physiological and psycho-motoric tests were performed before and after the work-shift. Except for minor statistical deviations, neither convincing dose-dependent acute effects could be demonstrated with regression analyses in male volunteers at the exposure levels evaluated, nor were significant differences found when applying group statistics (highly toluene-exposed group versus volunteers with negligible exposure). Due to the rather large number of participants, the predictive power of the study is high, especially when compared with previous publications. In two psycho-physiological tests, a few more female volunteers with quite low toluene body burdens (<340 microg/l blood) showed relatively low scores when compared with participants of the reference group. Although evidence for a medical relevance is meager, the small numbers of participants, in both the exposure and the reference groups, hamper a reliable interpretation of the results concerning exposure levels above 85 microg toluene/l blood, and it is difficult to take confounding factors adequately into account. For the end points evaluated and under occupational conditions, neither blood toluene levels of 850 to 1700 microg/l (in the highest exposure group [EXPO-IV] with 56 participants), as measured 1/2 (+/-1/2) h after the work-shift, nor ambient air concentrations (time-weighted average over 6 h) between 50 and 100 ppm (188-375 mg/m(3)) were convincingly associated with alterations in psycho-physiological and psycho-motoric performances or increased the frequency of subjective complaints in male volunteers. For higher dose ranges of toluene exposure (i.e. >1700 microg toluene/l blood [or >100 ppm in ambient air]), our data set is too small for far reaching conclusions. Our data are insufficient for conclusions on a possibly higher susceptibility to toluene of some female workers. Results of kinetic studies and possible effects of long-term exposure are discussed in two accompanying publications (Neubert et al., 2001; Gericke et al., 2001).

Multicenter field trial on possible health effects of toluene. III. Evaluation of effects after long-term exposure.

In rotogravure industry, contributing considerably to mass color printing of catalogues and magazines, toluene is still extensively used as paint solvent, and many printers have been exposed to this chemical for several decades. Information on adverse health effects associated with long-term toluene exposure is still controversial. In a multi-center study, adverse health effects possibly associated with long-term toluene exposure were evaluated. In 12 rotogravure factories, 1226 male volunteers were recruited, and sufficient information on exposure and on medical data was compiled for about 1077 of them. Evaluations included: physical examination, standard tests of psycho-physiological and psycho-motoric performances, self-report of subjective symptoms, and data on a variety of laboratory blood tests. The medical data were correlated with the length (months) of toluene exposure, and a rough estimate of the extent of exposure (i.e. highly exposed printers and their helpers versus employees working at locations with low or negligible toluene exposure). A small reference group (n=109) was selected from companies of the paper industry. When linear regression curves were calculated (test results versus duration of exposure), extremely low overall coefficients of determination (r(2) adj.) of a few percent were estimated within the data clouds, with sometimes statistically significant P-values. Closer analyses revealed a strong influence of the confounding factor age, no clustering of abnormal values of highly toluene-exposed volunteers, and the vast majority or all values of the highly and long-term toluene-exposed participants staying within the reference ranges. Thus, no medical relevance of P-values <0.05 could be recognized in this evaluation, and there may have been some border-line deviations or results largely occurring by chance in the large trial. In a small cluster of the many rotogravure printers toluene-exposed for more than 20 years, the highest systolic blood pressure values of the study were found, but many possible confounding factors were not taken into account. Data on acute exposure and possible effects are presented in accompanying papers (Neubert et al., 2001a, Neubert et al., 2001b). Restricting the conclusions to the end points evaluated as well as the apparent limitations of the evaluation, no evidence was found that long-term occupational toluene exposure extending over several decades in the rotogravure industry in the Western part of Germany was convincingly associated with chronic adverse health effects or convincingly altered surrogate markers in still working male volunteers. Several peculiarities and pitfalls arising when interpreting medical data associated with such a type of environmental exposure must be considered. Reversibility of alterations previously induced at higher levels of toluene-exposure, as well as a healthy workers effect, cannot be excluded for some of the medical end points evaluated.

Serratus posterior muscles: anatomy, clinical relevance, and function.

The serratus posterior superior and inferior muscles are generally considered clinically insignificant muscles that, based on attachments, probably function in respiration. Interestingly, however, there is no evidence supporting a respiratory role for these muscles. In fact, some electromyographic data refute a respiratory function for these muscles. We suggest that the serratus posterior muscles function primarily in proprioception. Further, these muscles, especially the superior, have been implicated in myofascial pain syndromes and therefore may have greater clinical relevance than commonly attributed to them.

Application to drug-food interactions of living cells as in vitro model expressing cytochrome P450 activity: enzyme inhibition by lemon juice.

Classical inhibitors of human cytochrome P450 3A4 activity, such as ketoconazol and quercetin, are tested to prove the efficiency of a new metabolisation model using living entire cells. Grapefruit juice is a well-known potent inhibitor of cytochrome P450 3A4 activity. With regard to the clinical relevance of grapefruit juice-drug interactions, an investigation of other common juices is undertaken with this in vitro model. The CYP3A4 activity is measured by the formation of the 6beta-hydroxytestosterone, which is quantified by an isocratic high performance liquid chromatography. It is demonstrated for the first time that lemon juice significantly inhibits by 60+/-3% the CYP3A4-mediated oxidation. Grapefruit juice inhibits this activity by 82+/-4%. The mechanism of lemon juice inhibition is competitive, whereas it is mixed for grapefruit juice. These results suggest that our in vitro model combined with our analytical method is applicable for the investigation of the inhibition of CYP3A4 not only by chemical inhibitors but also by natural food products.

Widowhood and illness: a comparison of social network characteristics in France, Germany, Japan, and the United States.

This study examined social network characteristics of adults aged 70 to 90 years in relation to widowhood and illness in France, Germany, Japan, and the United States. Participants were drawn from representative samples from each of the 4 countries (total N = 1,331). Resource deficit profiles based on whether respondents were widowed, ill, both, or neither were directly related to social network characteristics for German and Japanese adults, were differentially related by gender and age for French adults, and were not related to social networks of Americans. Country, gender, and age differences in total network size, proportion of close network members, and frequency of contact with network members are reported. Similarities and differences found in the associations between normative late-life deficits and social network characteristics in the 4 countries point to the importance of investigating sociocultural factors that mediate the impact of resource loss and afford life quality in very old age.

Limitations in activities of daily living: towards a better understanding of subthreshold mental disorders in old age.

Based on a representative sample of elderly subjects, a description of the limitations in activities of daily living (ADL) and instrumental ADL (IADL) at subthreshold levels of dementia and depression is presented and compared against a sample of psychiatric non-cases and samples with specified levels of the respective illnesses. Additionally, it was analyzed whether these limitations are useful diagnostic markers with regard to subdiagnostic psychiatric disorders. Even at subthreshold levels of depression and dementia, elderly people suffer quite extensively from ADL and IADL limitations. However, multifactorial analyses indicate little evidence that these limitations are specific for psychiatric morbidity, be it at subdiagnostic or specified levels. By and large, ADL and IADL limitations in an elderly sample have to be considered instead as consequences of physical health-related comorbidity. Thus, issues regarding the treatment of ADL and IADL limitations at subdiagnostic as well as specified levels of psychiatric morbidity may not be solved from a psychiatric point of view alone, and a multifactorial, i.e., multiprofessional, perspective is strongly recommended.

Time use of old and very old Berliners: productive and consumptive activities as functions of resources.

OBJECTIVES: The aims of this study were to examine time use of elderly women and men and to explain age- and gender-related variance in activity levels in terms of differences in available resources. METHODS: Activities reported in an elderly sample stratified for age and gender (N = 485, Age: 70-103 years) were aggregated into three classes: regenerative, productive, and consumptive activities and regressed on income, presence of a partner in the household, education, walking mobility, and labor force participation. RESULTS: Levels in productive and consumptive activities were decreased in the old-old. Moreover, young-old women spent more time working in the household than any other group. Most of the age- and gender-related variance in activity levels could be explained by differences in available resources. For men, living with a partner was associated with less time spent for productive activities and enhanced leisure time, whereas for women, the reverse was observed. The expected reduction of unpaid work time as a function of income (income effect) was not observed. DISCUSSION: Elderly individuals do contribute to societal production. Allocation of time to productive and consumptive activities is a function of available resources, amounts and effects of which differ for young-old and old-old as well as for women and men.

[Everyday activities in depression and dementia in the elderly. Results of the Berlin study on aging]. / Alltagsaktivitäten bei Depression und Demenz im hohen Alter. Ergebnisse der Berliner Altersstudie.

We investigated time use of persons assigned to seven groups on the basis of psychiatric diagnoses: (a) no dementia or depression symptoms, (b) individuals with dementia symptoms but no DSM-III-R-diagnosis, (c) individuals with dementia according to DSM-III-R, (d) individuals with depression symptoms but no diagnosis, (e) individuals with depression not further specified (NFS), (f) individuals with depression according to DSM-III-R, and (g) individuals with symptoms of both dementia and depression. In general, time-use parameters were similar across the groups. As expected, however, we found differences in specific dimensions. Demented and depressed individuals differed from others with respect to the duration of passive phases and receptive leisure. Instrumental activities, active leisure, length of the waking day, and time spent alone were indicators with differential validity regarding dementia diagnoses--partly even after controlling for physical morbidity. Moreover, we were able to differentiate between dementia and depression on the basis of instrumental activities after controlling for physical morbidity.

Daily life in very old age: everyday activities as expression of successful living.

The goals of this article are (a) to describe the daily life of the very old in terms of frequency, duration, variety, and social and physical contexts of activities, and (b) to examine the effects of background variables (e.g., age, sex, residential and marital status, income, and education) on late life activity engagement. A representative sample of 516 adults aged 70-105 was interviewed about their activities using the Yesterday Interview. In contrast to most research on activity engagement, this measurement approach allows for assessment of both the type and context of activities engaged in during the day preceding the interview. The results indicated high frequencies of obligatory activities but also showed substantial time spent in discretionary activities, with television viewing occupying most of the participants' leisure time. Most activities were done alone and at home. In bivariate and multiple regression analyses, age and residential status had the strongest association with activity frequency, duration, and variety; the oldest-old and those residing in long-term care facilities had lower levels of activity engagement. Results are discussed in terms of their relevance for successful aging.

[Dementias and daily competence: effects beyond ADL and IADL]. / Demenzerkrankungen und Alltagskompetenz: Effekte auch jenseits von ADL und IADL.

Using a time-budget method in a 3 year longitudinal study with a control group design, substantial reductions in the engagement of nonobligatory instrumental, social, and leisure activities could be found in a group of mildly to moderately demented patients. Controlling these changes for differences in baseline parameters, the dementia-specific reduction was about 1 1/2 hours compared to a non-psychiatric control group. These clinically relevant changes in activity levels underscore the importance of these activity domains with regard to the development of diagnostically useful indicators at the early stages of dementia. Time-budget methods seem to be particularly useful to close the diagnostic gap with regard to the assessment of everyday competence indicators especially at early stages of the dementia illness.

[Depression in the very elderly]. / Depression bei Hochbetagten. Ergebnisse der Berliner Altersstudie.

In the Berlin Aging Study (BASE) an age and gender stratified sample of 516 persons aged 70 to over 100 was assessed by means of the semi-structured GMS-A interview, the CES-D-self-rating scale and the Hamiltion-Depression-observer-rating scale. Prevalence rates were 4.8% for Major Depression, 9.1% for all DSM III-R specified depressive disorders and 26.9% of subthreshold depression was included. There was no increase in prevalence rates with age but an increase in scores on the self rating CES-D. The prevalence rates for DSM III-R specified depression in females was 10.3% and almost double that of men (5.6%). Depressed persons do not show significant cognitive impairment as measured with the MMSE in comparison to controls. As compared to the total sample higher prevalence rates of overall depression were seen in persons with multimorbidity (36.8%) and lower rates in married persons. 13.2% of the elderly talked about feeling tired with life, 7.9% had thoughts about death and 1.2% reported suicidal ideation, which was closely linked to depressive disorders. In 44% of depressed cases undertreatment was observed. Only 6% got Antidepressants but 40% benzodiazepines.

Ethyl acetate extraction procedure and isocratic high-performance liquid chromatographic assay for testosterone metabolites in cell microsomes.

An isocratic reversed-phase high-performance liquid chromatography (HPLC) method was developed and validated for separation of testosterone and its main metabolites over the nominal range 20 to 40 microg/ml and 280 to 4600 ng/ml, respectively. Mobile phase composition (phosphate buffer-methanol-acetonitrile, 50:38.5:11.5) was optimised by studying the influence of numerous chromatographic parameters. The most critical one was the ratio CH3CN/CH3OH. Good recoveries (around 90% for all compounds) and an improved specificity were assessed by a double ethyl acetate extraction of biological samples. According to the performance criteria tested, the method could be applied to enzymatic inhibition and induction in vitro studies.

The role of gender in very old age: profiles of functioning and everyday life patterns.

Older men and women have different life contexts as a function of differential longevity and socio-structural opportunities over the life course. The question is whether gender-related differences also occur in psychological and everyday functioning in older adults. Examined were 258 men and 258 women between the ages of 70 and 103 years (M = 85 years), participants in the Berlin Aging Study. Significant gender differences were observed in 13 of 28 aspects of personality, social relationships, everyday activity patterns, and reported well-being. Cluster analysis identified 11 subgroups whose profiles of life conditions and health and psychological functioning could be categorized as more or less desirable (functional). The relative risk of a less desirable profile was 1.6 times higher for women than for men. For older adults, gender as a variable carries differences in physical frailty and life conditions that likely have consequences for psychological functioning.

Everyday functioning and successful aging: the impact of resources.

The goal of this article is to examine differential aging in everyday functioning between resource-rich and resource-poor older adults. Four groups of older adults were identified on the basis of 2 distinct resource factors: a Sensorimotor-Cognitive factor and a Social-Personality factor. The resource-richest group consisted of those participants who were above the median in both factors; those falling below the median in both factors comprised the resource-poorest group; and 2 additional groups consisted of older adults who were above the median in either 1 of the 2 factors. At the level of mean differences, the 4 groups differed in the length of the waking day, the variability in activities, the frequency of intellectual-cultural and social-relational activities, and resting times. Considering age differences there are more and larger negative age effects in the resource-poorest group than in the resource-richest one. The metamodel of selective optimization with compensation is used to interpret the findings.

Everyday activity patterns and sensory functioning in old age.

In the present study the authors investigated the relationship between visual and auditory acuity and everyday activity functioning. Participants were 516 older adults (70-103 years; equal numbers of men and women) who were members of the age-stratified Berlin Aging Study. Two categories of everyday activity functioning, perceived competence with basic activities of daily living (BaCo; basic competence) and amount of participation in discretionary social and leisure tasks (ExCo; expanded competence), were examined. The results revealed that sensory acuity, particularly vision, was a significant predictor of both BaCo and ExCo (rs ranging from .32 to .47). Indeed, hearing and vision could explain most of the age-related variance in everyday activities. At the same time, in the context of a broader model, evidence for the differential prediction of BaCo and ExCo was found, although there was also evidence for strong general age-related predictive variance that was common to both measures. Discussion focuses on the role of sensory acuity constructs as mediators of age-related variance in psychological and behavioral outcomes and the potential causal implications of this mediation.

In vivo analysis of metabolic dynamics in Saccharomyces cerevisiae: II. Mathematical model.

A mathematical model of glycolysis in Saccharomyces cerevisiae is presented. The model is based on rate equations for the individual reactions and aims to predict changes in the levels of intra- and extracellular metabolites after a glucose pulse, as described in part I of this study. Kinetic analysis focuses on a time scale of seconds, thereby neglecting biosynthesis of new enzymes. The model structure and experimental observations are related to the aerobic growth of the yeast. The model is based on material balance equations of the key metabolites in the extracellular environment, the cytoplasm and the mitochondria, and includes mechanistically based, experimentally matched rate equations for the individual enzymes. The model includes removal of metabolites from glycolysis and TCC for biosynthesis, and also compartmentation and translocation of adenine nucleotides. The model was verified by in vivo diagnosis of intracellular enzymes, which includes the decomposition of the network of reactions to reduce the number of parameters to be estimated simultaneously. Additionally, sensitivity analysis guarantees that only those parameters are estimated that contribute to systems trajectory with reasonable sensitivity. The model predictions and experimental observations agree reasonably well for most of the metabolites, except for pyruvate and adenine nucleotides. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 592-608, 1997.

In vivo analysis of metabolic dynamics in Saccharomyces cerevisiae : I. Experimental observations.

The goal of this work was to obtain rapid sampling technique to measure transient metabolites in vivo. First, a pulse of glucose was added to a culture of the yeast Saccharomyces cerevisiae growing aerobically under glucose limitation. Next, samples were removed at 2 to 5 s intervals and quenched using methods that depend on the metabolite measured. Extracellular glucose, excreted products, as well as glycolytic intermediates (G6P, F6P, FBP, GAP, 3-PG, PEP, Pyr) and cometabolites (ATP, ADP, AMP, NAD(+), NADH) were measured using enzymatic or HPLC methods. Significant differences between the adenine nucleotide concentrations in the cytoplasm and mitochondria indicated the importance of compartmentation for the regulation of the glycolysis. Changes in the intra- and extracellular levels of metabolites confirmed that glycolysis is regulated on a time scale of seconds. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 305-316, 1997.

In vivo investigations of glucose transport in Saccharomyces cerevisiae.

In the present study, the glucose transport into the yeast Saccharomyces cerevisiae has been investigated. The approach suggested is based on a rapid sampling technique for studying the dynamic response of the yeast to rapid changes in extracellular glucose concentrations. For this purpose a concentrated glucose solution has been injected into a continuous culture at steady state growth conditions resulting in a shift of the extracellular glucose level. Samples have been taken every 5 s for determination of extracellular glucose and intracellular glucose-6-phosphate concentrations. Attempts to fit the experimental observations with simulations from existing models failed. The mechanism then proposed is based on a facilitated diffusion of glucose superimposed by an inhibition of glucose-6-phosphate. The use of the so-called in vivo approach suggested in this article appears to be proper, because the investigations can be performed at defined physiological states of the microbial cultures. Furthermore, the experimental observations are not being corrupted by the preparation of the samples for the transport studies as it happens during radioactive measurements. (c) 1996 John Wiley & Sons, Inc.