Degree Of Overgrowth Research Articles

Evaluation of overgrowth in pediatric radius fractures

PurposeForearm fractures are the most frequent long bone fractures in children. There have been many reports of differences in leg length due to overgrowth in lower extremity fractures. However, reports of such overgrowth in fractures of the upper extremity are rare. The purpose of this study was to investigate the relationship between angulation and overgrowth in pediatric radius fractures. We hypothesized that more angular deformation of the fracture would result in a periosteal transection and more overgrowth. MethodsRetrospectively, between 2013 and 2022, 14 patients under 16 years of age (mean age 9.43 years; 10 boys, four girls) with unilateral radius shaft or metaphyseal fracture without physeal injury, and a minimum follow-up of 12 months, were included. Demographic factors were analyzed; age, sex, body mass index (BMI), right or left. We evaluated the radiologic parameters; ulnar variances, degree of angularity before intervention, fracture gap and treatment options. The patients underwent conservative or surgical treatment. ResultsThe mean follow-up period was 27.9 months (range, 13–53 months). Eight patients underwent cast treatment, and six patients underwent surgical treatment. The difference in ulnar variances between the unaffected side and fracture side were statistically significant (P < 0.001). Sex, age, left or right, height, weight, and BMI were not statistically significant. The surgical treatment group (P = 0.013) and the sum of the maximum angularity (P = 0.017) were statistically significant. When the sum of the maximum angularity(SMA) was 30° or more, the ulnar variances were statistically significant, compared with the case where the SMA was less than 30°. The clinical results evaluated at the last outpatient follow-up were good in all patients. ConclusionsFirst, this study implies that the degree of angulation of the fracture may affect the overgrowth of the radius in case of radius shaft or metaphyseal fracture, without physeal injury. Second, it implies that the degree of overgrowth may increase with surgical treatment, as opposed to that with conservative treatment. Level of evidenceLevel IV, Retrospective study

О НАХОЖДЕНИИ РЕДКОГО ВИДА OVALONA KARELICA (STENROOS, 1897) (BRANCHIOPODA: ANOMOPODA: CHYDORIDAE) В ПОЙМЕННЫХ ОЗЕРАХ ХОПЕРСКОГО ЗАПОВЕДНИКА

Ovalona karelica (Stenroose, 1897) was first discovered for the invertebrate fauna of the Voronezh region south of the main habitat. It is a rare benthic species of sladocerans crustaceans (Crustacea, Cladocera). The species was encountered among macrophytes in thickets Typha angustifolia (L.) and Potamogeton lucens (L.) in two floodplain lakes of the Khopersky Nature Reserve in summer. The explored small lakes, where the species was found, are distinguished by the peculiarity of the floodplain regime; they are flooded from the main river in medium and high water years and remain connected to each other for some time. Lake Bolshoe Podpesochnoe has an area of 2.7 hectares and a maximum depth of up to 6 m. It is characterized by a low degree of overgrowing – 25%, the distance to the river Khoper is 1.1 km, last flooding was noted in 2018. The area of the lake Maloe Podpesochnoe is 1.9 ha, the maximum depth is up to 5 m, the degree of overgrowth is 35–40%, the distance to the river is 0.9 km, the last flood was in 2018. The size of the individuals encountered was from 380 to 420 microns, the abundance varied from 90 to 550 ind./m3, the share in the total number of planktonic invertebrates was from 0.1 to 0.32%. The discovery of Ovalona karelica is associated with the specificity of its habitat conditions and small number, and this also indicates a poor study of the fauna of phytophilic and benthic invertebrates in small floodplain water bodies.

Assessment of Peat Extraction Range and Vegetation Succession on the Baligówka Degraded Peat Bog (Central Europe) Using the ALS Data and Orthophotomap

The Baligówka peat bog is one of the peat bogs of the Orawa-Nowy Targ Basin—the largest complex of wetlands in the Polish Carpathians. Its area has declined in the past as a result of drainage and peat exploitation, which caused a bad hydrological condition and it is gradually overgrown by non-peat bog medium and high vegetation. The research uses models derived from airborne laser scanning (ALS) and an orthophotomap to delimit the bog and divide it into parts and assess the range of drainage ditches and vegetation. The area of the peat dome along with 3 sites of peat exploitation is currently 159.6 ha, while the ecotone zone is 105.9 ha. Both sections are separated by a steep post-mining slope. The medium and high vegetation areas cover 44% of the peat bog; its location is related to the dense drainage system in the southern part of the dome. The parameters of the Baligówka peat bog: area, size and extent of drainage system, and the degree of overgrowth by high vegetation, are the subject of research towards the protection under the Natura 2000 network (PLH120016) and the establishment of a plan for restoration activities.

Zooplankton of small reservoirs of the desert zone of Kazakhstan

The purpose of the work is to study the abundance and biomass of zooplankton communities of small reservoirs to assess the possibility of their use for fishery purposes. The article presents the results of a survey of 10 reservoirs of the middle desert and desert plains of the Central Asian type in September 2020. Small reservoirs and lakes of the region (0.01–0.52 km²) are freshwater, shallow (average depth 0.5–2.3 m), with a high degree of overgrowth of coastal (25–60%) and aquatic vegetation (60–90%). Eight of them are at the lower level of mesotrophy in terms of organic matter content. Lakes Mozgovoy and Kosmurat are mesoeutrophic and oligotrophic reservoirs. In most reservoirs at the time of the study, summer water temperatures were noted during the day (18.3–23.7 °C). A feature of the six reservoirs was the high content of phosphorus ions. The optimal level of this element was in the three upper reservoirs of the Kenes cascade due to the inflow of water from the mountains. The species composition of zooplankton in September is poor, the number of species ranged from 2 to 13. The basis of quantitative characteristics were planktonic and benthic Copepoda or Rotifera. The exception was oz. Cerebral, in which Cladocera prevailed at the expense of representatives of the Chydoridae. The biomass of zooplankton in the lakes was also quite low from 5.3 to 832.5 mg/m³. Thus, according to S.P. Kitaev’s trophic scale, reservoirs belong to the oligotrophic type. A comparative analysis of the zooplankton state in autumn and in other seasons shows a consistently low productivity of arid cenoses in conditions of low water and significant overgrowth. To improve the productivity of reservoirs and their further fishery use, it is necessary to optimize the habitat of aquatic organisms with an improvement in the water content regime and a decrease in the level of overgrowth in them.

Changes in Soil Features and Phytomass during Vegetation Succession in Sandy Areas

This research was conducted on an area of inland sands characterised by various degrees of overgrowth by vegetation and soil stabilisation. This landscape’s origin is not natural but is connected to human industrial activities dating from early medieval times, which created a powerful centre for mining and metallurgy. This study aims to identify the changes in the above- and belowground phytomass in the initial stages of succession and their influence on the chemical properties and morphology of the soil. It was found that Salix arenaria dominated in primary phytomass production in all plots tested. The amounts of this species found in each community were as follows: 8.55 kg/400 m2 (algae–mosses), 188.97 kg/400 m2 (sand grassland–willow), 123.44 kg/400 m2 (pine–willow–mosses), 14.63 kg/400 m2 (sand grassland–mosses–willow), and 196.55 kg/400 m2 (willow–pine–sand grassland). A notable share of Koeleria glauca was found in the phytomass production of Plots IV (45.73 kg) and V (86.16 kg). Basic soil properties (pH, Corg, Nt), available plant elements (P), and plant nutrients (Ca, Mg, K, P, Fe) beneath the dominant plant species were examined. Soil acidity (pH) varied greatly, ranging from acidic (pH = 3.2) to weakly acidic (pH = 6.3). The content of organic carbon (Corg) in individual plots beneath the dominant species in the humus horizon ranged from 0.28% to 1.42%. The maximum contents of organic carbon and total nitrogen were found in organic (O) and organic-humus (OA) horizons. The highest Pavail content was found in organic and organic-humus horizons, ranging from 10.41 to 65.23 mg/kg, and in mineral horizons under K. glauca (24.10 mg/kg) and Salix acutifola (25.11 mg/kg). The soil features and phytomass were varied differently across individual sites, representing different stages of succession.

Taxonomic revision of the genus Carinolithus (Early - Middle Jurassic) based on morphometric analyses and diagenesis observations: Implications for biostratigraphy and evolutionary trends

We applied morphometric analyses performed with a polarizing light microscope on a total of 100 specimens of Carinolithus superbus and C. magharensis to clarify the taxonomy based on measurements of total height (TH), stem height (SH), stem width (SW), proximal shield width (PS), distal shield width (DS) and thickness of the distal shield (TDS). Statistical analyses showed that three of these parameters, namely the DS, TDS and SW, are diagnostic for taxa discrimination. New taxa include C. superbus subsp. crassus subsp. nov. and C. magharensis subsp. minor subsp. nov. Specimens of C. cantaluppii were qualitatively investigated to assess the potential role of secondary modifications and our results revealed that, indeed, C. cantaluppii is a diagenetic artefact due to different degrees of overgrowth on specimens of C. poulnabronei, C. superbus subsp. crassus, C. superbus subsp. superbus, C. magharensis subsp. minor and C. magharensis subsp. magharensis. This implies that C. cantaluppii is not a true taxon, and the overgrowth phase of Carinolithus specimens is an effective proxy to assess the diagenetic degree. The morphometry-based revised taxonomy of the genus Carinolithus was applied to improve the biostratigraphic resolution of the Toarcian-Aalenian interval, with further implications for the reconstruction of evolutionary trends.

Overgrowth of the Femur After Internal Fixation in Children With Femoral Shaft Fracture-A Multicenter Study.

To evaluate overgrowth after internal fixation for pediatric femur fracture and to identify any factors related with overgrowth in terms of fracture type and fixation method. Retrospective comparative study. Multicenter, children's hospital and general hospital. Eighty-seven children between 4 and 10 years of age were included. Length-stable fracture was noted in 49 children, and length-unstable fracture was found in 38 children. Thirty-six children were treated by minimal invasive plate osteosynthesis (MIPO), and elastic stable intramedullary nail fixation (ESIN) was used in 51 children. The degree of overgrowth after internal fixation compared to fracture type, fracture site, and surgical method. Multivariable logistic regression analysis was conducted to identify factors related with overgrowth. The average overgrowth of the femur was 10.5 ± 7.3 mm. There was no patient who required correction for final leg length discrepancy (>2 cm). There was no significant difference in overgrowth between ESIN (9.9 ± 7.2 mm) and MIPO (11.2 ± 7.6 mm) (P = 0.417). Overgrowth was similar among length-unstable fractures (12.3 ± 7.4 mm) and length-stable fractures (9.2 ± 7.0 mm), although it was statistically greater in length-unstable fractures (P = 0.048). In the MIPO group, length-unstable fractures were associated with an increased log odds of 6.873 for overgrowth of the femur (P = 0.042). Femur overgrowth after internal fixation seems to not be a clinically significant problem, regardless of whether that be for length-stable or length-unstable fractures and whether they were treated by MIPO or ESIN. Length-unstable fracture may be a risk factor for overgrowth in children. However, the difference is very small, and the postoperative overgrowth would likely not be a significant factor in deciding the surgical plan. Therapeutic Level III. See Instructions for authors for a complete description of levels of evidence.

РАЗРАБОТКА ПРОГРАММ ДЛЯ РЕШЕНИЯ ЗАДАЧ В ОБЛАСТИ ЗАЩИТЫ ОКРУЖАЮЩЕЙ СРЕДЫ НА ВОДОСБОРНЫХ ТЕРРИТОРИЯХ

The purpose of this work is to develop software for calculating maximum permissible discharges and methods for assessing the overgrowth of water bodies with higher aquatic plants using the publicly available Google Earth program. In this paper, research has been carried out to improve the environmental monitoring system in catchment areas. A new approach is proposed for calculating the maximum allowable discharge for the current volume of water in the reservoir at a specific time. To implement the approach, software has been developed in which calculations are made to determine the value based on the actual volume of water in the Rybinsk reservoir based on the date of the expected discharge of pollutants from enterprises and the current content of pollutants in the water. A method has been developed for assessing the overgrowth of water bodies by higher aquatic plants using the publicly available Google Earth program, which will make it possible to make a forecast of siltation of reservoirs based on the degree of overgrowth. On the basis of the program Google Earth the dynamics of overgrowing of the lake Bezdonnoe is determined on the basis of space images for the 2013, 2015 and 2019 year relative to the 2009 year.

Assessment of the Erosion Stability of Slopes in Terms of Digression and the Degree of Overgrowth

Agroecological systems of slopes experience stress due to constant dynamic movements, especially on the slopes of high steepness. We have formulated the idea of critical levels in the dynamic process of slope agroecological systems, which is subsequently considered as an indicator of sustainability. When analyzing the dynamic processes on the slopes, we identified the digression of the slope surface under the influence of erosion processes as a critical one. The object of research is the erosion slopes of ravines and gullies in the forest-steppe conditions of the Volga upland. The purpose of the study is to develop parameters for assessing the stability of erosion slopes based on the results of research and analysis of literature sources. Results and discussion. It is proposed to refer to the dynamics changes not only in species composition, but also changes in the degree of degradation in terms of overgrowth of slope areas, allowing to establish the processes of secondary succession as the destruction of the slope surface. According to our concept the changes of species diversity on the erosion slopes may be accompanied by the appearance of alien plants in consequence of the stability, biological diversity and protective functions of the protective forest plantations loss. The number of species may increase, but the erosion slope gradually loses its stability. Quantitative assessment of the degree of overgrowth in terms of undergrowth and their qualitative characteristics give an idea of compliance of the forest conditions on the slope with environmental requirements for self-seeding tree species. It is found that the number of self-seeding on the slopes with increasing stage of digression naturally decreases. The number of self-seeding, compared with seedlings, 2-4 times less, regardless of the degree of digression of the slope. On the control and on the site of stage I of digression, the number of shoots of self-seeding clearly differ, which affects the incidence rate. In other areas, the occurrence is 53 -100%, which confirms the uneven of overgrowing of the slope area.

БИОЛОГИЧЕСКАЯ МЕЛИОРАЦИЯ АЗОВСКИХ ЛИМАНОВ КРАСНОДАРСКОГО КРАЯ И ВОЗМОЖНОСТИ ИСПОЛЬЗОВАНИЯ СРЕДСТВ, ПОЛУЧЕННЫХ В КАЧЕСТВЕ КОМПЕНСАЦИИ УЩЕРБА, НАНЕСЕННОГО ВОДНЫМ БИОЛОГИЧЕСКИМ РЕСУРСАМ

The author has carried out a retrospective analysis of environmental data about the Azov limans of the Krasnodar Krai. The increasing liman deterioration leading to their complete disappearance has been noted. Assessment of the priority of liman fish economy has been given. In terms of biological melioration there have been offered measures on stocking limans with herbivorous fish species of different age: grass carp Ctenopharyngodon idella and white silver carp Hypophthalmichthys molitrix , and determined necessary amounts of yearly stocking of the Azov limans. Modern data on the overgrowth in the water area of the Azov limans by higher aquatic vegetation have been presented in the context of the main groups of limans. The groups of limans were graded according to the priority of conducting biological melioration measures in them and practical recommendations were given on the quantity and places of stocking of the Azov limans grass carp and white silver carp depending on the degree of overgrowth. The necessity of using the funds received as compensation for the harm to water biological resources in the Krasnodar Krai for the artificial reproduction of grass carp and white silver carp and their introduction into the Azov limans has been substantiated. The article shows that stocking limans with herberous fish species will both ensure ameliorative effect and increase amount of fish commercial output.

Temporally variable diagenetic overgrowth on deep-sea nannofossil carbonates across Palaeogene hyperthermals and implications for isotopic analyses

Abstract Calcareous nannofossil assemblages of deep-sea sediments were subjected to intensive diagenetic alterations during early Palaeogene hyperthermal events. These alterations may have significantly modified bulk isotopic and trace metal signals and nannofossil preservation, thus biassing palaeoceanographic and palaeoecological interpretation. We present a detailed characterisation of the temporal variation in degree of diagenetic overgrowth on nannoliths during the PETM and Early Eocene Thermal Maximum (ETM2) using scanning electron microscopy (SEM), and explore in detail the consequences of these changes in overgrowth for interpretation of nannofossil assemblages and geochemical records covering the ETM2 at ODP Site 1265 where the event is well recognised. Results show that the nannofossil genera Discoaster and Zygrhablithus are particularly receptive to significant amounts of diagenetic calcite overgrowth, which was confirmed by Sr/Ca variations within single discoasters. Overgrowths show a strong correlation with changes in sediment carbonate content across the hyperthermals, with notably less overgrowth in low carbonate intervals. This secondary calcite affects stable isotope, notably oxygen isotopes, and assemblage composition modifying the dissolution susceptibility of taxa. In particular, the size fraction with a high contribution of overgrown discoasters has heavier δ18O values. Size fractions that are mainly composed of primary calcite give lighter δ18O values, and reveal a conspicuous early warming trend across ETM2 that appears to be attenuated in fractions with a major contribution of secondary calcite. Hence, coccolith-based indices based on the degree of overgrowth may be used to evaluate the degree of diagenetic alteration, as to improve precision and accuracy of the interpretation of nannofossil-based stable isotope records and abundance data.

Водная и прибрежно-водная растительность рек Чулым и Каргат (Западная Сибирь)

Coenotic diversity of aquatic and semiaquatic vegetation of the Chulym and Kargat rivers was revealed, which was 25 syntaxa of association rank of the Braun-Blanquet approach. Plant communities, dominated by Nuphar lutea (association Potamogetono–Nupharetum luteae) are the most common in the rivers surveyed. Plant communities of Oenanthetalia aquaticae are well represented in the both rivers. The degree of overgrowth is maximal in the upper course of both rivers, and it significantly decreases from the upper course to the lower. The overgrowth was minimal in the river mouth. New association Stuckenietum macrocarpae Kipriyanova was described.

The degree of overgrowth of the Rybinsk Reservoir and productivity of its vegetation cover

The data on the degree of overgrowth of the Rybinsk Reservoir and reserves of macrophytes biomass received in 2003 and 2009 are presented. It is shown that, in years with low water levels, vast areas of shallows with thickets of coastal aquatic plants dry up and, therefore, the degree of weediness of the reservoir and reserves of macrophyte biomass within it fall significantly. At a high water level, some of them are flooded, which leads to a significant increase in the degree of weediness of the reservoir. Each time it is higher than the previous peak, which testifies to the pulsating character of the overgrowths and to the general tendency toward a slower reduction of the reservoir area.

Combining Quantitative Textural and Geochemical Studies to Understand the Solidification Processes of a Granite Porphyry: Shanggusi, East Qinling, China

Igneous rock textures reflect the cooling history of the parental magma. Combined with chemical data, they can provide physical and chemical information about the evolution of a magma body. The petrographic textures and chemical compositions of 21 coarse- and fine-grained granite samples along an ∼250 m horizontal outcrop of the Shanggusi granite porphyry are presented in this case study. The coarse-grained granite porphyry is an early intrusion, and the fine-grained granite dykes, mostly intruded into the granite porphyry, are later intrusions. The studied samples have nearly homogeneous major element bulk-rock and mineral compositions, but show large variations in their trace element compositions and textural characteristics. The trace element data suggest the influence of hydrous fluids (possibly enriched in CO2, F, and Cl) in the evolution of the plutonic body. Textural analysis of the coarse-grained granite porphyry indicates that the crystal size distribution (CSD) slopes, intercepts and total numbers of groundmass decrease from the center to the margin of the intrusion in contrast to the maximum diameter of the crystals (Lmax) (average length of the four largest quartz crystals for each sample); however, most fine-grained samples and the groundmass of the coarse-grained samples show concave-down CSDs, indicating textural coarsening. Quartz CSDs in the coarse-grained samples are kinked, with a steep-sloped log–linear section representing small crystals (<1 mm) and a shallow-sloped log–linear section representing large crystals (>1 mm). These two crystal populations are interpreted as resulting from a shift in cooling regime. The straight CSDs of two fine-grained samples may be due to a different cooling history. In general, the spatial variation of the CSD patterns can be attributed to various degrees of overgrowth and mechanical compaction. The quartz phenocrysts in several coarse-grained samples exhibit a high degree of alignment, which may be the result of magmatic flow. By integrating the field geology, geochemistry and quantitative textural data from the horizontal profile of the Shanggusi granite porphyry, it is suggested that hydrous fluids at the top of the intrusion not only controlled the fractionation of elements but also affected its cooling history. Fluid migration-controlled undercooling can explain the solidification processes in the Shanggusi intrusion, and may also be prevalent in other fluid-rich shallow intrusions. Quantitative integration of textural and geochemical data for igneous rocks can contribute to our understanding of the relationships between physical and chemical processes in a magma system, and provide relatively comprehensive insights into the petrogenesis of granites.

Antagonistic effect of two isolates of Trichoderma harzianum against postharvest pathogens of tomato (Lycopersicon esculentum)

Pathogenicity test of all fungi (14 different isolates) isolated from both infected tomato fruits and the surface wash of other healthy fruits had different pathogenicity rates. The genus Rhizopus sp. was the most pathogenic one followed by Fusarium sp. Trichoderma harzianum isolates (T3 and T4) had a different pattern of antagonism against the tested pathogens. In dual plate test of the antagonistic action of T3 and T24 against the postharvest pathogens, clear zone size ranged between 1 and 4 and 3 and 6 mm by T3 and T24, respectively. The antagonists (T3 and T24) didn't show inhibition zone against Rhizopus sp., but they could overgrow it by 100% after 9 days of incubation. Mostly, all the other postharvest isolates showed high degree of overgrowth by T3 than T24. The two antagonists failed to overgrow Aspergillus species except for A. niger (3) which was overgrown by T3. Volatile and non-volatile metabolite tests indicated that mycelial growth of Penicillium stekii was significantly inhibited by T3 and T24 more than the other tested pathogens. The inhibition of A. niger (1) was 12% by non-volatile metabolites of T24 produced after 1 day incubation, and reached to 97% inhibition by the metabolites of 3 days. Interestingly, inhibition of Aspergillus sp. by volatile compounds of T3 and T24 was 2% and 20%, respectively, whereas the inhibition of the same pathogen by non-volatile compounds reached 75% and 87%, respectively. The results of slice assay clearly indicate that T. harzianum (T3 and T24) could provide a complete protection to tomato slices from the infection of the tested pathogens. After 3 days of incubation, Trichoderma suppressed the linear growth of these pathogens on tomato slices and the percentage of suppression was significant and ranged between 80 and 100%, except with Rhizopus sp. the suppression reached 33% only.

The dynamics of the restoration of mechanical damage to colonies of the scleractinian coral Porites lutea under conditions of competition with algal settlers for substratum

Natural and anthropogenic catastrophes in the last decades of the 20th century and at the beginning of the new century have evoked significant changes in the biological diversity of coral reefs, viz., the mortality of hermatypic scleractinian corals that are replaced by communities of marine algae and seaweeds. In this connection, the study of the dynamics of algal colonization of a newly formed substratum and competition for the substratum between hermatypic corals and algae is of topical interest. This paper describes the results of investigations conducted in 2003 at the Sesoko Marine Biological Station of Ryukyu University (Okinawa, Japan). Colonies of the massive scleractinian coral Porites lutea were sampled from a fringing reef of Sesoko Island. Damages were inflicted on the upper portions of the colonies, the damaged coral fragments were placed in aquaria and maintained for six months under different light intensities in the absence of herbivorous and corallivorous animals. The experiments showed that under bright (70–90% of incident photosynthetically active radiation, PAR0) and under moderate light (20–30% of PAR0), the damaged parts of colonies of about 25 cm2 were overgrown by newly formed polyps within six months. Under dim light (2–5% of PAR0), this period was not sufficient for recovery from lesions. During the first month, the recovery rate of colonies was the highest and depended on the physiological state of the corals and light intensity: in bright and moderate light it was two times and more higher than under low light. During the subsequent months, the recovery rate was significantly lower and depended mainly on the degree of overgrowth of dead portions with algae and on their species composition. Under bright and moderate light, algal colonization of damaged colonies started with the settling of colonial and filamentous diatoms, cyanobacteria and green algae, followed by the formation of the algal turf community. Communities of red calcareous crusts and fleshy algae were mainly formed on damaged corals under low light. A comparison of experimental results showed that damaged colonies maintained in aquaria in the absence of herbivorous and corallivorous animals recovered 1.5 times faster than in the sea. We hypothesize that herbivorous fish have a negative rather than positive influence on the recovery of damaged colonies.

Tissue responses against immunoisolating alginate-PLL capsules in the immediate posttransplant period.

Alginate-polylysine (PLL) capsules are commonly applied for immunoisolation of living cells for the treatment of a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules with failure of the grafts as a consequence. Most studies addressing biocompatibility issues of alginate-PLL capsules have focused on the degree of overgrowth on the capsules after graft failure and not on the reaction against the capsules in the immediate posttransplant period. Therefore, capsules were implanted in the peritoneal cavity of rats and retrieved 1, 5, and 7 days later for histological examination and X-ray photoelectron spectroscopy analysis for evaluation of chemical changes at the capsule surface. After implantation, the nitrogen signal increased from 5% on day 0, to 8.6% on day 7, illustrating protein adsorption on the capsule's surface. This increase in protein content of the membrane was accompanied by an increase in the percentage of overgrown capsules from 0.5 +/- 0.3% on day 1 to 3.3 +/- 1.6% on day 7. The cellular overgrowth was composed of monocytes/macrophages, granulocytes, fibroblasts, erythrocytes, multinucleated giant cells, and basophils. This overgrowth was not statical as generally assumed but rather dynamic as illustrated by our observation that at day 1 after implantation we mainly found monocytes/macrophages and granulocytes that on later time points were substituted by fibroblasts. As the inflammatory reaction predictably interfere with survival of encapsulated cells, efforts should be made to suppress activities or recruitment of inflammatory cells. These efforts may be temporary rather than permanent because most inflammatory cells have disappeared after 2 weeks of implantation.

Zircon ages from an Archaean gneiss province in northern Sweden

Abstract U-Pb isotopic analyses for zircons from an Archaean granitoid gneiss west of the Tjarro supracrustal belt in northern Sweden are presented. Four size fractions showing different degrees of overgrowth on eu- to subhedral zircons are interpreted as reflecting a U-Pb isotopic disturbance during a metamorphic event between 2740 and 2694 Ma ago. Some indication of the primary zircon crystallization is given by the mean diffusion age (2834 ± 40 Ma, 18) of the core-dominated coarser fractions. Subsequent Proterozoic metamorphism, between 1900 and 1750 Ma ago, up to amphibolite facies has caused no significant imprint on the analysed zircons. Together with previous geochronological work, the result indicate the existence of large areas of Archaean crust between the Tjarro belt and the Caledonides.