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At least 469 records · Page 26Linked to original sources
PubMed1997

Serum protein standardization project in Japan: evaluation of an IFCC reference material (RPPHS/CRM470) and establishment of reference intervals.

Reference preparation for proteins in human serum (RPPHS), also called Certified Reference Material 470 (CRM 470), was prepared by the international Federation of Clinical Chemistry (IFCC) and is intended to serve as a new international plasma protein reference material. It is now being introduced into Japan. RPPHS possesses many excellent properties, including safety, stability, and accuracy in value assignment. Moreover, the physicochemical properties of its proteins are identical to those of fresh serum, giving it immunochemical behavior that is commutable with that of existing reference materials and calibrators in given immunoassays. Reference intervals of 13 serum proteins were determined for the first time using nephelometry and a new working calibrator assigned from RPPHS, which seems certain to play a critical role in the global standardization of specific protein immunoassays.

Age Factors↗
PubMed2001

Different ways to make a head.

In Drosophila, the establishment of the larval head and thorax depends on the transcription factors BICOID and HUNCHBACK, and on signalling mediated by the receptor tyrosine kinase TORSO. Genetic experiments described in two recent papers(1, 2) demonstrate that these factors can, to a large extent, replace each other, revealing a surprising degree of plasticity in establishing larval anterior structures. The commutability of developmental factors might in part reflect the evolutionary history of the system. BioEssays 23:8-11, 2001.

Animals↗
PubMed2005

The global burden due to occupational injury.

BACKGROUND: Occupational injuries are a public health problem, estimated to kill more than 300,000 workers worldwide every year and to cause many more cases of disability. We estimate the global burden of fatal and non-fatal unintentional occupational injuries for the year 2000. METHODS: The economically active population (EAP) of about 2.9 billion workers was used as a surrogate of the population at risk for occupational injuries. Occupational unintentional injury fatality rates for insured workers, by country, were used to estimate WHO regional rates. These were applied to regional EAP to estimate the number of deaths. In addition to mortality, the disability-adjusted life years (DALYs) lost, which measure both morbidity and mortality, were calculated for 14 WHO regions. RESULTS: Worldwide, hazardous conditions in the workplace were responsible for a minimum of 312,000 fatal unintentional occupational injuries. Together, fatal and non-fatal occupational injuries resulted in about 10.5 million DALYs; that is, about 3.5 years of healthy life are lost per 1,000 workers every year globally. Occupational risk factors are responsible for 8.8% of the global burden of mortality due to unintentional injuries and 8.1% of DALYs due to this outcome. CONCLUSIONS: Occupational injuries constitute a substantial global burden. However, our findings greatly underestimate the impact of occupational risk factors leading to injuries in the overall burden of disease. Our estimates could not include intentional injuries at work, or commuting injuries, due to lack of global data. Additional factors contributing to grave underestimation of occupational injuries include limited insurance coverage of workers and substantial under-reporting of fatal injuries in record-keeping systems globally. About 113,000 deaths were probably missed in our analyses due to under-reporting alone. It is clear that known prevention strategies need to be implemented widely to diminish the avoidable burden of injuries in the workplace.

Accidents, Occupational↗
PubMed1993

Community lead exposure.

In August, 1990, a regional transit authority began removing paint on two overhead bridges on a commuter railroad line running through a residential neighborhood of Lynn, Massachusetts, an industrial city north of Boston. The contracted work involved the sandblasting of existing bridge paint to prepare the surface for repainting. The sandblasting was conducted without shrouding or adequate worker protection. The bridge paint was not tested for lead content, nor were neighborhood residents informed of the operations prior to the commencement of the work. Following complaints by residents to the local and state health departments, a cease-work order was issued. Laboratory tests of paint samples revealed a lead content ranging from 5% to 15%. Sandblasting debris was evident throughout the adjacent neighborhood. What followed was a 3-month effort by state and local government officials and the transit authority and its contractors to assess, communicate, and remedy the damage done by the operations. Soil, dust, and blood samples were collected to assess environmental contamination and health effects. Notices were sent, meetings held, and informational sites established to inform community residents of the impact of the operations and remediation efforts. The local and Boston media provided extensive coverage of the incident and its aftermath. Remediation efforts involved the relocation of occupants from residences in proximity of the site and extensive clean-up of the interiors of affected homes by licensed lead abatement contractors. The cost of the cleanup was well over $1 million.(ABSTRACT TRUNCATED AT 250 WORDS)

Communication↗
PubMed2004

Identification of modifiable work-related factors that influence the risk of work disability in rheumatoid arthritis.

OBJECTIVE: To define work-related factors associated with increased risk of work disability (WD) in people with rheumatoid arthritis (RA). METHODS: Questionnaires were mailed to all RA patients who used a province-wide arthritis treatment program between 1991 and 1998 (n = 1,824). The association between risk factors and WD (defined as no paid work due to RA for at least 6 months) was assessed using multiple logistic regression analysis, controlling for significant sociodemographic and disease-related variables. RESULTS: Of the original 1,824 patients, 581 were eligible and responded to the questionnaire. Work survival analysis revealed a steady rate of WD starting early, with 7.5%, 18%, and 27% work disabled at 1, 5, and 10 years, respectively. Significant determinants in multiple logistic regression were physical function (Health Assessment Questionnaire), pain (visual analog scale), and 6 work-related factors: self employment, workstation modification, work importance, family support toward employment, commuting difficulty, and comfort telling coworkers about RA. CONCLUSION: Work disability occurs early in RA. Novel work-related factors were identified, which are potentially modifiable, to help RA patients stay employed.

Absenteeism↗
PubMed2004

Quantum mechanical considerations on the algebraic structure of central molecular chirality.

The chiral algebra of tetrahedral molecules, derived from Fischer's projections, is discussed in the framework of quantum mechanics. A "quantum chiral algebra" is obtained whose operators, acting as rotations or inversions, commute with the Hamiltonian of the system. It is shown that energy and chirality eigenstates are strictly related through the Heisenberg relations, while chirality operators "conserve" parity eigenstates.

Journal Article↗
PubMed1983

Audiotapes in continuing medical education.

The "ideal" tool for the physician, especially the one practicing in a rural area far removed from medical teaching centers, would be a learning instrument he or she could utilize anywhere, anytime. This paper traces the genesis and growth of a teaching tool that is now utilized worldwide because it comes close to that ideal of being useful in multitudinous locations where time is otherwise wasted, principally during automobile commuting.

Audiovisual Aids↗
PubMed2006

Colorectal cancer stage at diagnosis by socioeconomic and urban/rural status in California, 1988-2000.

BACKGROUND: Rural residence has been associated with increased risk of late stage cancer diagnosis, but it is unknown if this is related to lower socioeconomic status (SES) of rural residents or to other factors. This study examined the impacts of SES and urban/rural status on colorectal cancer (CRC) stage at diagnosis in California. METHODS: Cases of CRC among persons >or=50 years of age diagnosed from 1988-2000 were obtained from the California Cancer Registry. A composite census based SES measure was used in the analysis, and the RUCA (Rural Urban Commuting Areas) classification scheme was used to categorize the residence at diagnosis as urban, large town, or small town. Multivariate logistic regression was used to examine the association between SES, urban/rural status, and late stage at diagnosis. RESULTS: In multivariate models, SES had the strongest association with stage at diagnosis among individuals living in urban areas. As SES level increased, odds of late stage at diagnosis decreased. Individuals in the highest SES category had lower odds of being diagnosed at late stage when compared with those in the lowest SES category (O.R. = 0.91, 95% C.I. = 0.87, 0.94). For individuals who lived in large towns and small rural towns, SES was not significantly associated with stage at diagnosis. We found no significant differences in stage at diagnosis by urban/rural status within SES categories. CONCLUSIONS: These data suggest that the relationship between SES and the risk of late stage colorectal cancer varies among rural and urban populations. Further research into the factors that influence access to and utilization of colorectal cancer screening in rural areas is needed.

Aged↗
PubMed2006

Factors influencing distress in Indian cancer patients.

BACKGROUND: The current study set out to identify distress in cancer patients undergoing curative treatment within India. PATIENTS AND METHODS: This study was carried out to measure distress and contributory factors in 103 cancer patients undergoing treatment with curative intent. The patients were interviewed using the Distress Inventory for Cancer (DI-C). The data on social, demographic, clinical, treatment, and follow-up details was collected from case records. RESULTS AND CONCLUSION: The distress score for individual respondents ranged from 34 to 90 (mean 62.3). Patients with lower income, those who were single/widowed, or divorced, those living between 150 and 350 km (3-6 h commuting distance) from the cancer centre, presence of pain and patients with advanced tumours at presentation showed higher distress. A higher distress score correlated significantly with patients being lost to follow-up.

Cross-Sectional Studies↗
PubMed1999

Within-litter sibling aggression in spotted hyaenas: effect of maternal nursing, sex and age.

Models that address facultative siblicide in avian species predict that the costs and benefits of sibling aggression will change in relation to the level of food provisioning by parents. In spotted hyaenas, Crocuta crocuta, one of the few mammalian species in which facultative siblicide occurs, aggression rates between siblings were highest when cubs competed for access to maternal milk. In the Serengeti National Park, Tanzania, nursing of cubs by spotted hyaena mothers was influenced by the migratory movements of herbivores and the social status of the mother. Consistent with predictions from avian models, rates of sibling aggression among spotted hyaena littermates were inversely related to levels of maternal input in terms of lactation. Long-distance foraging trips by mothers (commuting trips) resulted in low cub growth. Rates of aggression were higher in years when cub growth rates were low than in years when cub growth rates were medium or high. Rates of aggression between littermates belonging to high-ranking mothers, who nursed their cubs more frequently than low-ranking mothers, were lower than those between siblings of low-ranking mothers. Aggression rates in all-female and all-male litters were higher than in mixed-sex litters. Identical payoff expectations of same-sex litters may provide an explanation for this result. In accordance with predictions from life history theory, aggression rates declined with age and increasing reproductive value of siblings. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2000

Finescale topographical correlates of behavioural investment in offspring by female grey seals, Halichoerus grypus.

Grey seals breed colonially on substrates ranging from ice to rocky or sandy beaches. Clear differences in seal behaviour patterns exist among such broad classes of breeding habitat. However, finer scale topographical variation is likely to influence individual behaviour with consequences for pupping success. We examined topographical influences on the behaviour of breeding female grey seals by quantifying topography at a subseal size resolution. Using submetre resolution digital terrain models of two sites within a rocky breeding colony, we compared site topography in relation to observed differences in female behaviour at these sites. Females at both sites preferred breeding close to water (standing pools or sea) and frequently commuted between their pups and water. Topographical models indicated that one site was more costly for seals in terms of their locations and movements within the site. This was due to a lack of low-elevation land adjacent to the main access points from the sea and the reduced availability of pools. Females at this site showed reduced pup attendance and an increase in energetically costly behaviours, whilst females at the lower-cost site spent more time interacting with their pups and resting. These topographically induced behavioural differences are likely to affect the quantity and quality of pup provisioning by mothers and influence individual pupping site selection. Less costly sites are likely to be colonized preferentially and by larger, older and more dominant females, potentially generating finescale spatial heterogeneity in female quality within the breeding colony. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2000

Mechanisms for the formation and maintenance of traditional night roost aggregations in a territorial damselfly.

Communal roosting has been studied extensively in birds, but the mechanisms and functions of this taxonomically widespread behaviour pattern remain poorly understood. We studied the roosting behaviour of rubyspot damselflies, Hetaerina americana, in relation to sex and territorial status, and conducted field experiments to test for specific mechanisms of roost formation and maintenance. Both sexes tended to return close to their previous night's roost, but only males were significantly more roost site faithful than chance expectations based on individual day ranges. Males were more roost site faithful when they held mating territories. After acquiring a territory, males usually began roosting closer to the territory after a delay of a few days. Roosts were not located at sites that reduced the daily commuting distance between hunting areas and territories; males generally hunted closer to their territories than to their roosts. In field experiments, sites 'seeded' with synthetic models of male rubyspots attracted more recruits than vacant control sites and control sites seeded with nonrubyspot (clear-winged) damselfly models. Sites seeded repeatedly with rubyspot models often remained popular for roosting after the models were removed, suggesting that the models established new traditional roosts. These results indicate that conspecific attraction and individual spatial memory together may be sufficient to explain, at a proximate level, the traditional night roost aggregations of this species. We discuss these results in relation to functional hypotheses for roost site choice and fidelity. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1996

Empirical Recovery of Response Time Decomposition Rules I. Sample-Level Decomposition Tests

E. N. Dzhafarov and R. Schweickert (1995, Journal of Mathematical Psychology, 39, 285-314) developed a mathematical theory for the decomposability of response time (RT) into two component times that are selectively influenced by different factors and are either stochastically independent or perfectly positively stochastically interdependent (in which case they are increasing functions of a common random variable). In this theory, RT is obtained from its component times by means of an associative and commutative operation. For any such operation, there is a decomposition test, a relationship between observable RT distributions that holds if and (under mild constraints) only if the RTs are decomposable by means of this operation. In this paper, we construct a sample-level version of these decomposition tests that serve to determine whether RTs that are represented by finite samples are decomposable by means of a given operation (under a given form of stochastic relationship between component times, independence or perfect positive interdependence). The decision is based on the asymptotic p-values associated with the maximal distance between empirical distribution functions computed by combining in a certain way the RT samples corresponding to different treatments.

Journal Article↗
PubMed1999

The accuracy of distance measurements in solid-state NMR.

The accuracy with which distances can be measured using dipolar recoupling experiments in solid-state NMR is investigated. The relative precision of experiments in a three spin system versus an isolated spin pair is found to depend very strongly on the nature of the coupling Hamiltonian. The accuracy of distances measured in even the simplified three spin system is seen to be very poor for existing homonuclear recoupling Hamiltonians. This suggests that it would be difficult to exploit broadband homonuclear recoupling to measure geometrical information reliably in complex spin systems. These conclusions apply equally to both single-crystal studies and powder samples. In contrast, the presence of additional spins has marginal impact on the accuracy when the coupling Hamiltonians commute with each other, as in the case of heteronuclear recoupling. The possibility of creating such a Hamiltonian for homonuclear recoupling using a suitable rotor-synchronized pulse sequence is discussed.

Magnetic Resonance Spectroscopy↗
PubMed2000

Coherent cross-polarization theory for a spin-12 coupled to a general object

Zero-order average-Hamiltonian theory is used to extend the product-operator description of coherent spin-spin cross-polarization to the case of a spin-12 coupled to a general object, like a molecular rotor or a quantum oscillator. The object, which is not necessarily in a Boltzmann equilibrium state, is assumed to have no interaction with the lattice and no internal relaxation capacity. The Bloch-Wangsness-Redfield (BWR) theory for incoherent processes like spin-lattice relaxation does not apply for such an isolated spin-object pair. Nevertheless spectral density at the Larmor frequency, of key importance in BWR theory, also plays a central role in object-induced spin polarization. Spectral density in our theory is represented by quantum operators J(-) and J(+). If J(-) and J(+) do not commute, the spin-object coupling may cause spin polarization in an initially saturated spin system. This represents a coherent mechanism for spin cooling, which in specific cases may lead to enhanced spin polarization above the thermal equilibrium value. A master equation is derived for general spin-object cross-polarization, and applied to the case of a spin pair inside a uniaxial rotor, and a spin coupled to a microelectronic LC circuit. Copyright 2000 Academic Press.

Journal Article↗
PubMed1992

Epidemiological study of gastrointestinal and liver effects of carbon disulfide.

In the framework of an extensive health survey, 119 viscose rayon workers exposed to carbon disulfide (CS2) and 79 workers from other plants not exposed to any toxic agent in the working environment underwent a gastrointestinal examination including a self-administered questionnaire, abdominal palpation, percussion and a number of liver function tests. In the viscose rayon factory the working conditions have not changed since 1932. Personal monitoring performed in 17 jobs showed CS2 exposures varying from 4 to 112 mg.m-3. For each individual a cumulative CS2 exposure index (CS2 index) was calculated. Univariate analysis of the questionnaire findings showed significantly higher prevalences of anorexia (37.0% vs 11.4%, P less than 0.0001), vomiting (12.6% vs 3.8%, P = 0.04), and recent weight loss (10.9% vs 1.3%, P = 0.009) in the exposed than in the non-exposed workers. The exposed workers had a larger total number of gastrointestinal complaints and a larger proportion reported at least one complaint at least once a month than the non-exposed ones. Abdominal tenderness was very rare in both groups. In multiple logistic regression analysis, adjusting for alcohol intake, smoking, body mass index (BMI), coffee consumption, commuting time, stress at work, shift work, educational level, family history of ulcer disease and intake of medication, significant associations with exposure were found for anorexia (P = 0.0001), nausea (P = 0.009), vomiting (P = 0.002) and flatulence (P = 0.03). Stress at work was a determinant for quite a few digestive complaints, but shift work was not significantly associated with any of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1977

Immunodeficiency with lymphoid hyperplasia.

A 2 1/2-year-old boy presented with recurrent respiratory tract infections, generalized lymphadenopathy and hepatosplenomegaly. Immunologic evaluation revealed a deficiency of humoral immunity. Repeated lymph node biopsies during a 10-year follow-up constantly showed excessive follicular hyperplasia with huge germinal centers consisting of germinoblasts, but lacking plasma cells. The disease can be interpreted as a subtype of the common variable immunodeficiency in which the commutation of germinoblasts to plasma cells in the evolution of B cells is blocked.

B-Lymphocytes↗
PubMed1984

A simple model for the evolutionary emergence of novel properties.

In contradistinction to classical theories quantum mechanics sharply distinguishes between potential and essential properties of a system. The potential properties of a quantal system are described by a set of observables. The subset of those observables that commute with all others is called the center of observables and represents the essential properties, i.e. the properties actualized in each state of the system. If a quantum system is open its time evolution can change the center and turn merely potential properties into essential ones and vice versa. The temporal behavior of such a system clearly shows the characteristics of evolutionary change; quantum mechanics can describe how novel properties emerge in the course of time. This is in clear contrast to the behavior of Turing- or Belousov-Zhabotinskii type models where the evolutionary change only produces a refinement of an existing essential property and not something really new. - As an illustration we present a simple model with non-trivial evolutionary behavior.

Biological Evolution↗