Electron energy loss spectroscopy elucidates the elusive darkening of zinc potassium chromate in Georges Seurat's A Sunday on La Grande Jatte--1884.

The color darkening of selected brushstrokes of Georges Seurat's A Sunday on La Grande Jatte--1884 was noted as early as 1892. Artificial aging of model systems containing zinc yellow (K(2)O·4ZnCrO(4)·3H(2)O) mixed with linseed oil successfully replicated the phenomena observed on La Grande Jatte. Electron energy loss spectroscopy measurements performed on the uppermost few microns of thin sections of the paint layers (obtained with focused ion beam milling) determined that samples which turned olive green (aged at 90% RH, with SO(2) and light) contain mostly the altered species Cr(III) and that the ochre-yellow coloration of specimens aged at 50% RH with SO(2) and light is due to the presence of dichromate ions (Cr (VI)). The altered species are only present in the first few microns of paint and are likely poorly crystalline, so that they eluded other types of bulk and surface measurements, but they create a substantial color alteration at the surface of the paint films. A similar phenomenon was confirmed on a sample from La Grande Jatte, where Cr(III) and Cr(VI) dichromate ions were detected in the ochre-colored, altered brushstrokes of zinc yellow. Laboratory simulations demonstrated that the equilibrium between chromate and dichromate ions is reversible within the paint film and that the orange dichromate ions can be transformed back into bright yellow chromates by exposure to highly alkaline gases.

Bones of teleost fish demonstrate high fracture strain.

The endoskeleton of teleosts (bony fish) includes a vertebral spine with articulating rib bones (RBs) similar to humans and further encompasses mineralized tissues that are not found in mammals, including intermuscular bones (IBs). RBs form through endochondral ossification and protect the inner organs, and IBs form through intramembranous ossification within the myosepta and play a role in force transmission and propulsion during locomotion. Based on previous findings suggesting that IBs show a much higher ability for fracture strain compared to mammalian bones, this study aims to investigate whether this ability is general to teleost bones or specific to IBs. We analyzed RBs and IBs of 25 North Atlantic Herring fish. RBs were analyzed using micro-mechanical tensile testing and micro-computed tomography, and both RB and IB were additionally analyzed with Raman spectroscopy. Based on our previous results from IB, we found that RBs are more elastically deformable (on average, 50% higher yield strain and 115% higher elastic work) and stronger (55% higher fracture stress) than values reported for IBs. However, these differences were neither associated with a higher Young's modulus nor a higher degree of mineralization in RBs. Astonishingly, RBs and IBs showed similar fracture strains (12-15% on average, reaching up to 20%), reflecting a much higher ability for tensile deformation than reported for mammalian bone, and further highlighting the biomimetic potential of teleost fish bones for inspiring innovative biomaterials.

Crtap and p3h1 knock out zebrafish support defective collagen chaperoning as the cause of their osteogenesis imperfecta phenotype.

Prolyl 3-hydroxylation is a rare collagen type I post translational modification in fibrillar collagens. The primary 3Hyp substrate sites in type I collagen are targeted by an endoplasmic reticulum (ER) complex composed by cartilage associated protein (CRTAP), prolyl 3-hydroxylase 1 (P3H1) and prolyl cis/trans isomerase B, whose mutations cause recessive forms of osteogenesis imperfecta with impaired levels of α1(I)3Hyp986. The absence of collagen type I 3Hyp in wild type zebrafish provides the unique opportunity to clarify the role of the complex in vertebrate. Zebrafish knock outs for crtap and p3h1 were generated by CRISPR/Cas9. Mutant fish have the typical OI patients' reduced size, body disproportion and altered mineralization. Vertebral body fusions, deformities and fractures are accompanied to reduced size, thickness and bone volume. Intracellularly, collagen type I is overmodified, and partially retained causing enlarged ER cisternae. In the extracellular matrix the abnormal collagen type I assembles in disorganized fibers characterized by altered diameter. The data support the defective chaperone role of the 3-hydroxylation complex as the primary cause of the skeletal phenotype.

Evaluation of external exposures of the population of Ozyorsk, Russia, with luminescence measurements of bricks.

Recently discovered historical documents indicate that large releases of noble gases (mainly (41)Ar and radioactive isotopes of Kr and Xe) from the Mayak Production Association (MPA) over the period from 1948 to 1956 may have caused considerable external exposures of both, inhabitants of Ozyorsk and former inhabitants of villages at the upper Techa River. To quantify this exposure, seven brick samples from three buildings in Ozyorsk, located 8-10 km north-northwest from the radioactive gas release points, were taken. The absorbed dose in brick was measured in a depth interval of 3-13 mm below the exposed surface of the bricks by means of the thermoluminescence (TL) and the optically stimulated luminescence (OSL) method. Generally, luminescence properties using TL were more favorable for precise dose determination than using OSL, but within their uncertainties the results from both methods agree well with each other. The absorbed dose due to natural radiation was assessed and subtracted under the assumption of the bricks to be completely dry. The weighted average of the anthropogenic dose for all samples measured by TL and OSL is 10 +/- 9 and 1 +/- 9 mGy, respectively. An upper limit for a possible anthropogenic dose in brick that would not be detected due to the measurement uncertainties is estimated at 24 mGy. This corresponds to an effective dose of about 21 mSv. A similar range of values is obtained in recently published dispersion calculations that were based on reconstructed MPA releases. It is concluded that the release of radioactive noble gases from the radiochemical and reactor plants at Mayak PA did not lead to a significant external exposure of the population of Ozyorsk. In addition, the study demonstrates the detection limit for anthropogenic doses in ca. 60-year-old bricks to be about 24 mGy, if luminescence methods are used.

Microstructure, mineral and mechanical properties of teleost intermuscular bones.

There is an increasing interest in understanding teleost bone biomechanics in several scientific communities, for instance as interesting biomaterials with specific structure-function relationships. Intermuscular bones of teleost fish have previously been described to play a role in the mechanical force transmission between muscle and bone, but their biomechanical properties are not yet fully described. Here, we have investigated intermuscular bones (IBs) of the North Atlantic Herring with regard to their structure and micro-architecture, mineral-related properties, and micro-mechanical tensile properties. A total of 115 IBs from 18 fish were investigated. One cohort of IBs, containing 20 bones from 2 smaller fish and 23 bones of 3 larger fish, was used for mechanical testing, wide-angle X-ray scattering, and scanning electron microscopy. Another cohort, containing 36 bones from 7 smaller fish and 36 bones from 6 larger fish, was used for microCT. Results show some astonishing properties of the IBs: (i) IBs present higher ductility, lower Young's modulus but similar strength and TMD (Tissue Mineral Density) compared to mammalian bone, and (ii) IBs from small fish were 49% higher in Young's modulus than fish bones from larger fish while their TMD was not statistically different and crystal length was 8% higher in large fish bones. Our results revealed that teleost IB presents a hybrid nature of soft and hard tissue that differs from other bone types, which might be associated with their evolution from mineralized tendons. This study provides new data regarding teleost fish bone biomechanical and micro-structural properties.

Simulation of giant fibre development in biopsy samples from pig longissimus muscle.

The incidence of hyper-contracted giant fibres in pig postmortem skeletal muscle is closely related to poor meat quality in terms of pale, soft, and exudative pork. Detection of a predisposition to develop giant fibres in live pigs could help to predict pork quality and to exclude affected pigs from genetic selection. The abundance and proportion of giant fibres in longissimus muscle were highest in Piétrain followed by Landrace, Large White, and Leicoma pigs of market weight. The postmortem development of giant fibres could be successfully simulated in vitro incubating biopsy samples from longissimus muscle at 37°C for 60min. For repeated measurements on three samples the intraclass correlation coefficient for the number of giant fibres/cm(2) was ϑˆ(3)=0.69 for biopsy and ϑˆ(3)=0.87 for carcass samples. "Simulated" giant fibres exhibited ultrastructural changes in plasma membrane, myofibrils, mitochondria, and sarcoplasmatic reticulum as shown previously for giant fibres in carcass samples.

Ecological half-lives of 90Sr and 137Cs in terrestrial and aquatic ecosystems.

This paper describes the long-term behaviour of (90)Sr and (137)Cs in foods, feeds and a variety of environmental media. The long-term behaviour is quantified by means of the ecological half-life which integrates all processes that cause a decrease of activity in a given medium such as leaching, fixation and erosion. A large number of long-term time series of concentrations of radiocaesium and radiostrontium in these media have been identified and re-evaluated using a standardised statistical procedure to establish reference data sets of ecological half-lives. By example of undisturbed soils and marine water bodies it is shown that the ecological half-life concept is questionable if the distribution of the radionuclide of interest within the medium studied is non-uniform and if mixing and transport processes within this medium, therefore, are of considerable importance during the time period of observation.

A recruitment model for selecting residents.

The process of selecting residents is an important issue in medical training. In an attempt to quantify and thereby objectify this process, a model for selection was developed. The model, using scaled scores reflective of each of the applicants' characteristics, was used to rank applicants in the Department of Physical Medicine and Rehabilitation at the Medical College of Wisconsin, Milwaukee. Data derived from the selection process were analyzed over a three-year period, 1986-1989. Statistical analysis of the data showed that as few as three experienced faculty members were needed to interview reliably. The statistically significant correlation (p less than .01) between those who interviewed and those who did not interview was necessarily influenced by the fact that those who did not interview had access to the narrative descriptors of those who did. These findings suggest that the use of this recruitment model would permit a more cost-effective approach to the selection of residents.

It is possible to increase skeletal muscle fibre number in utero.

The administration of porcine somatotropin (pST) to pregnant sows during early gestation (day 10 to 24) induced the formation of significantly more muscle fibres in the semitendinosus muscle of the fetuses, representing a higher growth capacity of skeletal muscle. The pST-treatment during late pregnancy (day 80 to 94) accelerated the development of the fetus resulting in higher body weights and advanced stage of maturity at birth.

The cellular compatibility of five endodontic sealers during the setting period.

The purpose of this study was to evaluate the cellular compatibility of five endodontic sealers in the first 24 h after mixing. Specimens of N2, Endomethasone, Apexit, AH Plus, and Ketac Endo were extracted with cell culture medium 0, 1, 5, and 24 h after mixing. Eluates were tested for cytotoxicity with immortal 3T3 cells and primary human periodontal ligament fibroblasts using XTT-assays. Data were analyzed for statistically significant differences by means of Dunnett's t tests (p < 0.05). All extracts of N2 completely inhibited cell metabolism (p < 0.05). Similar effects were provoked by the first three eluates of Endomethasone, but the 24-h extract irritated cells significantly less (p < 0.05). Severe cytotoxicity was also observed with all Ketac Endo extracts (p < 0.05). A significant inhibition of mitochondrial activity was induced by the first (3T3) or the first and second eluate (periodontal ligament fibroblasts) of AH Plus (p < 0.05). The subsequent eluates of this sealer and all extracts of Apexit did not reveal any cytotoxic potency.

Administration of recombinant porcine somatotropin (rpST) changes hormone and metabolic status during early pregnancy.

The objective of this study was to examine the effects of somatotropin (ST) on porcine reproductive and metabolic statuses during early pregnancy. Four pregnant crossbred gilts received 6 mg of recombinant porcine somatotropin (rpST) daily from days 10 to 27 after artificial insemination while six pregnant gilts served as controls. Blood samples were taken on days 8, 10, 12, 14, 18, 22, and 27 prior to rpST injections (8:00 h) and subsequently at 9:00, 10:00, 12:00, 14:00, 16:00, 18:00, and 20:00 h. On all remaining days of treatment, samples were taken once daily before injections (8:00 h). The samples were assayed for the metabolic hormones: ST, insulin-like growth factor I (IGF-I), insulin, thyroxine (T(4)), triiodothyronine (T(3)), and cortisol; for metabolites: free fatty acids (FFA) and glucose; and for the reproductive hormones: luteinizing hormone (LH), progesterone, estradiol-17beta, estrone sulfate, and prostaglandin F(2alpha). Delivery of rpST daily induced a 20- to 40-fold increase in plasma ST concentrations. Moreover, repeated administration of rpST resulted in a continuous increase in plasma IGF-I concentration (P < 0.001), from 191.0 +/- 22.3-340.0 +/- 15.3 ng/mL 24 h after initial injection to 591.3 +/- 46.8 ng/mL after final injections. Mean serum insulin tended to be greater in rpST-treated gilts. Blood concentrations of T(4) were reduced (P < 0.05) from day 14 of gestation in treated gilts while T(3) concentrations remained unchanged. Concentrations of both glucose and FFA were greater (P < 0.01) and cortisol concentrations were unchanged in treated gilts. Changes in reproductive steroid hormones were minimally affected. Circulating progesterone (P = 0.078), and estradiol-17beta (P = 0.087) concentrations tended to be lower in treated animals. These data show that treatment of pregnant gilts with rpST during early gestation mainly impacts metabolic rather than reproductive status.

Growth- and breed-related changes of muscle fiber characteristics in cattle.

The objective of this study was to investigate the growth- and breed-related changes of muscle fiber characteristics in cattle and their importance to meat quality. Four cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus as a beef type, Galloway as a hardy type, Holstein Friesian as a dairy type, and double-muscled Belgian Blue as an extreme type for muscle growth were used. Between 5 and 17 bulls of each breed were slaughtered at 0, 2, 4, 6, 12, 18, and 24 mo of age. Muscle fiber traits were determined and classified by computerized image analysis, and several measures of meat quality were also determined, including shear force value, meat color, and i.m. fat content. The postnatal growth of semitendinosus muscle in cattle was characterized by a nearly 10-fold increase of muscle fiber area from birth to 24 mo of age. In the first few months after birth, a transformation of type IIA fibers into IIB fibers was found, whereas type I fibers were nearly unaffected by age. The apparent total muscle fiber number of semitendinosus muscle did not increase during postnatal life. These results confirm that the fiber number is determined in embryonic development. Throughout the study, the double-muscled Belgian Blue (BBDM) bulls had almost twice the fiber number of the other breeds, emphasizing a more extensive hyperplasia of muscle fibers during embryonic development in BBDM compared with the other three breeds. The apparent number of type I fibers was, however, not affected by breed, which suggests that the additional fibers found in BBDM postnatally were type IIB and IIA fibers. We did not find significant differences in muscle fiber total number, muscle fiber type frequencies, or meat quality characteristics among breeds, with the exception of BBDM. Having pooled the four breeds, paler meat was related to a higher frequency of type IIB fibers, a lower area of type IIA and type I fiber, and a higher total muscle fiber number. These findings based on data of double muscling give us some hints for biological causes for the variation of meat quality. Further investigation, in particular within each breed, is necessary to identify the superior fiber traits for bovine meat production.

Structural and functional characteristics of muscle fibres in pigs with different malignant hyperthermia susceptibility (MHS) and different meat quality.

In pigs, intensive growth of the musculature is often accompanied by malignant hyperthermia susceptibility (MHS; n gene) and poorer meat quality. Using histological and histochemical methods, different fibre characteristics in the Longissimus muscle were found in Pietrain×German Landrace pigs with this gene defect. Compared to MHS homozygous negative pigs, groups with the n gene had increased diameters of the mean fibre types and increased glycolytic metabolic potential, as shown by a higher frequency of the fast twitch glycolytic type and a lower frequency of the slow twitch oxidative fibre type. Differences between the groups were also found in the number of angular and giant fibre types. Furthermore, a positive correlation was found between the frequency of oxidative fibres and the relative enzyme activity of NADH tetrazolium reductase. The changes correlated with lower pH and higher drip loss in meat from the MHS homozygous positive group. In conclusion, the different muscle fibre characteristics can be interpreted as endogenous factors which influence the physiological condition in the muscle of the live animal and meat quality post mortem.

[Methodical investigations for selection of a histochemical routine-method of differentiating fibre types (author's transl)]. / Methodische Untersuchungen zur Auswahl einer histochemischen Routinemethode für die Differenzierung von Muskelfasertypen.

1. Transverse sections of two muscles of 20 pigs and 20 laboratory mice were studied methodically to ascertain a histochemical technique of differentiating fibre types suitable for routine-investigations. 2. The best results of four applied histochemical methods were obtained by the reaction for reduced disphosphopyridine nucleotide tetrazolium reductase (DPNH-TR). The comparison of the methods based on valuation-criterions as quality of reactions, expenditure of time and cost and requirements to the user. 3. The calculation of the variance-components showed for the evaluation of two samples (pigs) and one transverse section of muscle (mouse) per animal a good repeatability of the quantitative parameters of muscle fibre type composition.

Continuity of care. A teaching model.

Recent changes in health care mandate innovative approaches to teaching. Rehabilitation as part of the continuum of disability motivated the "continuity of care model." This model permits the presentation of rehabilitation in its global sense: from onset of injury through re-integration into the community. This report describes a curriculum for physical medicine and rehabilitation residents that comprises a three-phase approach to rehabilitation: acute care, inpatient rehabilitation and community re-entry. The curriculum is adaptable for medical students. A secondary benefit of the project for the resident is a better understanding of relevant cost benefit/cost effective concepts in the delivery of quality services. The close interaction of residents with community agencies permits these agencies to gain a better understanding of the medical needs of disabled people.

[Fat clogging, fat cell count and fat cell size in swine in relation to age and feeding intensity]. / Fettzuwachs, Fettzellzahl und Fettzellgrösse beim Schwein in Abhängigkeit vom Alter und von der Fütterungsintensität.

Growth dependent changes of fat gain, the number of fat cells in the cutlet muscle and the size of the fat cells in the bacon of the back were studied in dependence on feeding intensity with a total of 145 male castrates of the genotype (L X E) XSF. Between their 5th and 32nd weeks of life the animals were butchered at intervals of 3 weeks and the parameters were determined. The gain of fat and the intramuscular fat content were highest in the high-level variant (daily weight gain 720 g) and lowest in the low-level variant (daily weight gain 530 g). The diameter of the fat cells in the middle layer of the bacon of the back increased up to an age of 26 weeks and then remained constant. Differences between the feeding groups were registered; the animals of the high-level group had the biggest fat cells from the 14th week onwards. A nutrition-caused difference between the number of fat cells per mm2 of the cutlet muscle could not be found. The calculated total number of fat cells in the cutlet muscle increased due to growth up to an age of 26 weeks. The results provided basic knowledge of fat gain and influences on it in pigs and they indicate possibilities of making statements on fat retention determining the microstructure of the fat tissue of the living animal by means of biopsy.

Integration of physical medicine and rehabilitation into the undergraduate medical curriculum. The Undergraduate Education Committee of the Association of Academic Physiatrists Workgroup.

The incorporation of PM&R into the medical student curriculum thus provides benefits at multiple levels: to patients, to medical students, and to practitioners already in the field. The knowledge about PM&R gained by the medical student is spread to disciplines outside of PM&R through the learning of principles and specific factual data that can be applicable for practitioners caring for a variety of patients. It is the position of this organization that each academic department work to integrate education in PM&R into the medical school curriculum.

[Changes in the distribution of muscle fiber types in the M. longissimus dorsi of boars during growth, prepared by different histochemical methods]. / Veränderungen der Muskelfasertypenverteilung im M. longissimus dorsi von Ebern während des Wachstums, dargestellt mit verschiedenen histochemischen Methoden.

Samples of the M. longissimus dorsi from growing up pigs were taken by a shooting-biopsy. The types of muscle-fibers could be demonstrated by two different histochemical staining procedures. With these two histochemical staining procedures significant differences between the different structure of the muscle-fibers during increasing age of the pigs could be detected.

Economics of managed care in spinal cord injury.

OBJECTIVE: To determine and describe trends in economic variables related to the care of individuals with spinal cord injury (SCI) and significant changes in these trends coincident with major developments in medical care cost control. DATA SOURCES: Data from the National Spinal Cord Injury Statistical Center (NSCISC) database were used to review the economic trends in SCI management from 1973 to 1998 and their relation to managed care and other health care cost-containment measures. A panel of SCI health care specialists was interviewed to determine the appropriate data variables to be reviewed. The Shepherd Center Care Health Management Program, Atlanta, GA, is presented as an example of a fiscally successful managed care program for patients with SCI. DATA EXTRACTION: Data from the NSCISC database for the years studied were extracted and converted to a form suitable for analysis by means of the statistical software SAS. DATA SYNTHESIS: Statistical techniques included multiple regression analysis, logistic regression analysis, and model selection methods. CONCLUSIONS: Trends in economic variables, in the care of individuals with SCI show changes coincident with the introduction of Diagnostic Related Groups (DRGs) and managed care as models for provider reimbursement. Significant changes occurred in acute care charges, rehabilitation charges, length of stay, rehospitalization 1 year postinjury, time from injury to admission to a Model System, and discharges to a nursing home.