Effects of current-use fungicides and their mixtures on the feeding and survival of the key shredder Gammarus fossarum

Fungicides are frequently applied in agriculture and are subsequently detected in surface waters in total concentrations of up to several tens of micrograms per liter. These concentrations imply potential effects on aquatic communities and fundamental ecosystem functions such as leaf litter breakdown. In this context, the present study investigates sublethal and lethal effects of organic (azoxystrobin, carbendazim, cyprodinil, quinoxyfen, and tebuconazole) and inorganic (three copper (Cu)-based substances and sulfur) current-use fungicides and their mixtures on the key leaf-shredding invertebrate Gammarus fossarum. The feeding activity of fungicide-exposed gammarids was quantified as sublethal endpoint using a static (organic fungicides; 7 d test duration) or a semi-static (inorganic fungicides; 6 d test duration with a water exchange after 3 d) approach (n=30). EC50-values of organic fungicides were generally observed at concentrations resulting in less than 20% mortality, with the exception of carbendazim. With regard to feeding, quinoxyfen was the most toxic organic fungicide, followed by cyprodinil, carbendazim, azoxystrobin, and tebuconazole. Although all tested organic fungicides have dissimilar (intended) modes of action, a mixture experiment revealed a synergistic effect on gammarids' feeding at high concentrations when using "independent action" as the reference model (∼35% deviation between predicted and observed effect). This may be explained by the presence of a synergizing azole fungicide (i.e. tebuconazole) in this mixture. Furthermore, lethal concentrations of all Cu-based fungicides assessed in this study were comparable amongst one another. However, they differed markedly in their effective concentrations when using feeding activity as the endpoint, with Cu-sulfate being most toxic, followed by Cu-hydroxide and Cu-octanoate. In contrast, sulfur neither affected survival nor the feeding activity of gammarids (up to ∼5 mg/L) but reduced Cu-sulfate's toxicity when applied in a binary mixture. Sulfur-related metabolic processes which reduce the physiological availability of Cu may explain this antagonistic effect. For both fungicide mixtures, the present study thus uncovered deviations from the appropriate reference model, while ecotoxicological effects were observed at field relevant (total) fungicide concentrations. Additionally, for more than half of the tested single substances, a potential risk for Gammarus and thus for the ecological function mediated by these organisms was evident at concentrations measured in agriculturally influenced surface waters. These results suggest that risks to the fundamental ecosystem function of leaf litter breakdown posed by fungicides may not be adequately considered during the regulation of these compounds, which makes further experimental efforts necessary.

Forensic age estimation in living subjects based on ultrasound examination of the ossification of the olecranon

Radiation-free imaging procedures for the purposes of forensic age diagnosis are highly desirable, especially for children. With this in mind, the stage of ossification of the olecranon was prospectively determined in 309 male and 307 female healthy volunteers aged between 10 and 25 years, based on ultrasound. A four-stage classification system was used for this purpose. This stage classification system takes into account whether an isolated secondary ossification centre, an epiphyseal cartilage or an epiphysis which is completely fused with the diaphysis can be detected. The earliest observation of stage 2 was at 10.0 years in males and 10.1 years in females. Both findings are determined by the lower age limit of the sample and are thus not representative of the minimum age for ossification stage 2. Stage 3 was first noticed at age 13.5 years in males and 10.6 years in females. Stage 4 was first reached at age 13.7 years in males and 12.3 years in females. Hence, in our sample, ossification stage 3 can be seen as evidence that females have reached the age of 10 years and males the age of 13 years. In our sample, stage 4 provides evidence that a female individual has reached the age of 12 years. It was concluded that the results of our study should be validated using other samples.

Influence of the examiner's qualification and sources of error during stage determination of the medial clavicular epiphysis by means of computed tomography

Computed tomography (CT) of the medial clavicular epiphysis has been well established in forensic age estimations of living individuals undergoing criminal proceedings. The present study examines the influence of the examiner's qualification on the determination of the clavicular ossification stage. Additionally, the most frequent sources of error made during the stage assessment process should be uncovered. To this end, thin-slice CT scans of 1,420 clavicles were evaluated by one inexperienced and two experienced examiners. The latter did the evaluations in consensus. Two classification systems, a five-stage system and a substaging system for the main stages 2 and 3, were used. Prior to three of his six assessment sessions, the inexperienced examiner was specifically taught staging of clavicles. Comparison of the examiners' results revealed increasing inter- and intraobserver agreements with increasing state of qualification of the inexperienced examiner (from κ= 0.494 to 0.674 and from κ= 0.634 to 0.783, respectively). The attribution of a not-assessable anatomic shape variant to an ossification stage was identified as the most frequent error during stage determination (n= 349), followed by the overlooking of the epiphyseal scar defining stage 4 (n= 144). As to the clavicular substages, classifying substage 3a instead of 3b was found to be the most frequent error (n= 69). The data of this study indicate that κ values must not be considered as objective measures for inter- and intraobserver agreements. Furthermore, a high degree of specific qualification, particularly the knowledge about the diversity of anatomic shape variants, appears to be mandatory and indispensable for reliable evaluation of the medial clavicular epiphysis.

Sonographic examination of the apophysis of the iliac crest for forensic age estimation in living persons

The present study examines the applicability of ultrasound diagnostics in assessing the ossification processes of the apophysis of the Crista iliaca of the pelvis for the purposes of forensic age diagnostics in living persons. To this end, the apophyseal ossification stages were determined in 307 female and 309 male study participants aged between 10 and 25 years. In females, ossification stage I was identifiable at an age of 10.1 years at the earliest (x¯=11.8), ossification stage II at 11.2 years at the earliest (x¯=14.6), ossification stage III at 14.7 years at the earliest (x¯ =18.6), and ossification stage IV at 17.9 years at the earliest (x¯=22.7). In males, ossification stage I was observable from an age of 10.0 years (x¯=11.8), ossification stage II from 10.5 years (x¯=14.9), ossification stage III from 15.6 years (x¯=18.9), and ossification stage IV from 17.4 years (x¯=22.6). In forensic age estimation procedures in living persons, sonographic examination of the iliac crest apophysis makes it possible to minimise exposure of the individual to radiation in accordance with the existing legal basis for the use of X-rays on humans. In application areas with no legal basis to justify X-ray examinations, the accuracy of an age diagnosis can be improved by integrating skeletal maturity as a criterion.

[Dynamic hyperinflation in pulmonary arterial hypertension: "hyperinflator" and "non-hyperinflator"]

BACKGROUND

The dynamic decrease in inspiratory capacity (IC) during exercise with restriction of tidal volume (VT) is known as dynamic hyperinflation (DH) and is described mostly in patients with COPD differentiating between a "hyperinflator" and a "non-hyperinflator". Recent studies have revealed DH in patients with idiopathic pulmonary arterial hypertension (iPAH), but the influence of the DH on the reduced exercise capacity with exertional dyspnoae is still being debated.

METHODS

We analysed flow-volume curves during cardiopulmonary exercise testing (CPET) in idiopathic PAH (n = 19), in COPD (n = 17), in idiopathic pulmonary fibrosis (IPF) (n = 19) and a control group (n = 30). We measured IC at rest and during maximal exercise and furthermore ventilation, VT and oxygen uptake (VO2 peak). In iPAH a right heart catheter test and a 6-minute walk test (6MWT) were performed, also the B-type naturetic peptide (BNP) and the NYHA/WHO functional class were determined.

RESULTS

The IC decreased significantly in 11 PAH "hyperinflators" (PAH-H) (Δ IC: - 0.34 ± 0.14 L, p < 0.001) compared to 8 PAH "non-hyperinflators" (PAH-NH) (Δ IC: 0.08 ± 0.2 L). COPD patients exhibited a characteristic hyperinflation pattern with a decrease in IC throughout exercise (Δ IC: - 0.61 ± 0.3 L, p < 0.001), while patients with IPF (Δ IC: 0.03 ± 0.15 L) and the control group responsed to exercise with a non-hyperinflator pattern (Δ IC: 0.1 ± 0.2 L). Both PAH collectives showed a reduced IC/TLC, while VT/IC was elevated with a decreased peak VO2 and max. performance compared to the control group. Correlations of the IC rest/max (L) were shown in PAH-H and PAH-NH with the VO2 peak, max. performance and VT.

CONCLUSION

The analysis of flow-volume curves during CPET can indentify DH in a subgroup of patients with iPAH. The DH contributes significantly but slightly to the development of exertional limitations and dyspnoe in a subgroup of iPAH. Further studies with a larger sample size will be required to definitively measure the impact of the DH seen in these patients.

[Sonographic examination on the time frame of ossification of the distal fibula epiphysis]

In order to increase the reliability of forensic age estimations in living adolescents and young adults without justification for X-ray examinations, the establishment of radiation-free imaging procedures is desirable. In this study, the ossification stage of the right-hand distal fibula epiphysis was sonographically determined prospectively in 309 male and 307 female healthy volunteers. For this purpose a four-stage classification system was used. A sonographically determined ossification stage 3 permits the proof of completion of age 13 in boys and the proof of completion of age 12 in girls. In case of an ossification stage 4 the completion of age 14 in boys and the completion of age 13 in girls can be certified. In order to increase the level of reliability of age estimates, findings should be collected by at least two independent examiners who are experienced in the sonography of skeletons, followed by consensus-building.

Sonographic assessment of the ossification of the medial clavicular epiphysis in 616 individuals

Establishing radiation-free imaging methods for the assessment of clavicular ossification in forensic age determination is desirable as it reduces radiation exposure in living individuals. For this purpose the stage of ossification of the right medial clavicular epiphysis was determined prospectively using sonography in 309 male and 307 female healthy volunteers. The classification of stages according to Schulz et al. was used for this purpose. Stage 2 was first noticed at the age of 14.4 years in males, and at the age of 14.1 years in females. Stage 3 was first achieved by males at the age of 17.6 years and by females at the age of 17.4 years. Stage 4 first occurred in males at the age of 19.3 years and at the age of 18.9 years in females. The mean age for stage 1 was 13.6 years. The mean age of stage 2 ranged between 17.3 and 17.6 years. For stage 3 the mean age varied from 20.7 to 21.2 years, and for stage 4 from 23.3 to 23.5 years. It was concluded that sonographically determined stage 4 clavicular ossification provides evidence for the completion of the nineteenth year of life in males and the eighteenth year of life in females. In order to increase the reliability of age determination using this method it is recommended that findings be recorded by at least two experienced independent examiners who then reach a consensus.

Differences in the sensitivity among cryptic lineages of the Gammarus fossarum complex

Lineages that are at least superficially morphologically identical but genetically distinct are usually misclassified as a single nominal species and, hence, belong to a cryptic species complex, as for example observed for Gammarus fossarum. Since genetic differentiation between cryptic lineages of the G. fossarum complex is comparable to an interspecific level, deviations in physiological and behavioral characteristics are conceivable. The present study investigates for the first time deviations in the sensitivity between two cryptic G. fossarum lineages - namely lineage A and lineage B. Two size classes of both cryptic lineages were exposed in six independent experiments to different concentrations of the fungicide tebuconazole or the insecticide thiacloprid (each n=20) for seven days. Feeding rate on leaf discs was used as a measure of sensitivity. By combining the outcome of all bioassays in a meta-analysis, cryptic lineage A showed - with an approximate 50% more pronounced decline in feeding - a significantly higher overall sensitivity compared to lineage B (n=17). This was also obvious, when each chemical stressor was considered individually; however, data were not significant for thiacloprid. Although other reasons, like land-use of habitats around sampling sites and physiological characteristics of organisms, could not be excluded as driving factors, the results indicate that affiliation to a cryptic lineage is a potential explanatory variable for the observed deviations in sensitivity. As the present study considered only one population for each cryptic lineage, a final conclusion cannot yet be drawn. Hence, it is recommended to investigate behavioral and physiological deviations between cryptic lineages of the G. fossarum complex in further studies.

Ion Beam Induced Epitaxial Regrowth and Interfacial Amorphization of Compound Semiconductors

A review of MeV-ion beam induced crystallization (IBIEC) and interfacial amorphization (IBIIA) in III-V compounds (GaAs, InAs, GaP, InP) is given. The kinetics of IBIEC and IBIIA is studied as a function of the temperature, the density of the displacements v, and the ion dose rate j. Reversal temperatures TR for IBIEC ↔ IBIIA transitions are determined for the different materials showing characteristic dependences on v and j. The IBIEC rate is shown to be controlled by point defect diffusion towards the a/c-interface and additionally modified by the interface structure. The suppression of microtwin and stacking fault formation during IBIEC is explained by the fact that the ion beam modifies the orientation dependence of the crystallization kinetics avoiding the disintegration and (111)-faceting of the (100)-interface. For all the compound materials investigated the IBIEC process is stopped above critical temperatures and doses. The capture of diffasing defects by crystallites growing in the amorphous layers is considered to be responsible for the stopping of the IBIEC interface. Ways are demonstrated to avoid stopping, to achieve complete epitaxial regrowth also of thick layers, and to minimize the generation of stable damage in the crystallized layers. The limited temperature ranges for undisturbed IBIEC and IBIIA in III/V-compounds are explained by low nucleation barriers and high growth rates both of crystallites and of amorphous zones.

The influence of impaction on the rate of third molar mineralisation in male black Africans

One of the main criteria used in dental age diagnostics in living adolescents and young adults is assessment of the mineralisation stage of the third molars. In the case of Europid populations, it has been established that impaction status has an influence on the rate of mineralisation of the third molars. In view of this, a study was undertaken to determine whether the chronological process of wisdom tooth mineralisation is dependent upon impaction status in black Africans too. Orthopantomograms (553) of 437 male and 116 female black South Africans with verified birth dates in the age group between 10 and 26 years were studied. Mineralisation stage and impaction status were determined for all third molars. Statistical measures were calculated for the mandibular wisdom teeth at stages F, G and H and for the maxillary wisdom teeth at stage H in the male gender for both impacted and non-impacted third molars. It was ascertained that the minimum age in persons with impacted third molars, depending on the wisdom tooth observed, was 0.19-2.57 years higher than in those with non-impacted wisdom teeth. Test persons with impacted mandibular wisdom teeth at stage F or G were on average between 0.32 and 1.88 years older than those with non-impacted mandibular wisdom teeth. The 50 % probability values of impacted wisdom teeth at stage H were 1.85-3.31 years higher than those in non-impacted wisdom teeth. The conclusion was drawn that in male black Africans, impacted mandibular wisdom teeth mineralise more slowly than non-impacted lower third molars. The presence of impacted mandibular wisdom teeth in mineralisation stage H in male black Africans does not, however, furnish proof of completion of the 18(th) year of life beyond reasonable doubt.

Thiacloprid affects trophic interaction between gammarids and mayflies

Neonicotinoid insecticides like thiacloprid enter agricultural surface waters, where they may affect predator-prey-interactions, which are of central importance for ecosystems as well as the functions these systems provide. The effects of field relevant thiacloprid concentrations on the leaf consumption of Gammarus fossarum (Amphipoda) were assessed over 96 h (n = 13-17) in conjunction with its predation on Baetis rhodani (Ephemeroptera) nymphs. The predation by Gammarus increased significantly at 0.50-1.00 μg/L. Simultaneously, its leaf consumption decreased with increasing thiacloprid concentration. As a consequence of the increased predation at 1.00 μg/L, gammarids' dry weight rose significantly by 15% compared to the control. At 4.00 μg/L, the reduced leaf consumption was not compensated by an increase in predation causing a significantly reduced dry weight of Gammarus (∼20%). These results may finally suggest that thiacloprid adversely affects trophic interactions, potentially translating into alterations in ecosystem functions, like leaf litter breakdown and aquatic-terrestrial subsidies.