996 research outputs found
NEAR-SURFACE SOIL NITROGEN AND VEGETATION RESPONSE TO INVASIVE EMERALD ASH BORER IN FORESTED BLACK ASH WETLANDS OF THE WESTERN UPPER PENINSULA, MICHIGAN, USA
Invasive emerald ash borer (EAB) (Agrilus planipennis Fairmaire) poses an imminent threat to the structure and function of North American hardwood forests, particularly black ash (Fraxinus nigra Marshall), and alters the hydrologic and ecological services of their wetlands. Black ash trees regularly grow in seasonally saturated soils and are responsible for hydrologic regulation and nutrient cycling. In this study, a gradient of black ash wetlands impacted by EAB were monitored to assess vegetation changes and near-surface soil nitrogen availability. Vegetation community changes were intertwined with nitrogen cycle disturbances following EAB infestation. As black ash died and fell to the wetland, more total organic nitrogen was returned to the environment and promptly incorporated into the growing shrub and sapling layers. Assessing vegetation and biogeochemical changes along an EAB gradient in the environment improves our understanding of the ecological ramifications for a future landscape without black ash wetlands as they presently exist
Energy-filtered transmission electron microscopy of biological samples on highly transparent carbon nanomembranes
Ultrathin carbon nanomembranes (CNM) comprising crosslinked biphenyl
precursors have been tested as support films for energy-filtered transmission
electron microscopy (EFTEM) of biological specimens. Due to their high
transparency CNM are ideal substrates for electron energy loss spectroscopy
(EELS) and electron spectroscopic imaging (ESI) of stained and unstained
biological samples. Virtually background-free elemental maps of tobacco mosaic
virus (TMV) and ferritin have been obtained from samples supported by ~ 1 nm
thin CNM. Furthermore, we have tested conductive carbon nanomembranes (cCNM)
comprising nanocrystalline graphene, obtained by thermal treatment of CNM, as
supports for cryoEM of ice-embedded biological samples. We imaged ice-embedded
TMV on cCNM and compared the results with images of ice-embedded TMV on
conventional carbon film (CC), thus analyzing the gain in contrast for TMV on
cCNM in a quantitative manner. In addition we have developed a method for the
preparation of vitrified specimens, suspended over the holes of a conventional
holey carbon film, while backed by ultrathin cCNM
Evolution of reservoir properties in the Lower Triassic aquifer sandstones of the Thuringian Syncline in Central Germany
The Buntsandstein (Lower Triassic) aquifer sandstones of the Thuringian Syncline are important for water supply, geothermal energy and storage wells. The aim of this study was to analyse the control factors of the diagenetic and petrophysical properties of the Buntsandstein, and particularly the influence of varying depositional parameters, thermal history, subsidence and exhumation. The Thuringian Buntsandstein records fluvial, sandflat, lacustrine and eolian environments. The dominant reason for porosity loss in the sandstones is mechanical compaction. The permeabilities depend on their predominant depositional facies: fine grained lacustrine sandstones in the Lower Buntsandstein have low permeabilities (about 4 mD); conversely, Middle Buntsandstein sandflat, fluvial and eolian sandstones are moderately to highly permeable (27 – 108 mD). Thermal maturity data of Carboniferous, Permian and Triassic sediments provide information about the maximum burial depth of the Buntsandstein rocks. Between 1800 m and 3800 m of overburden must have been eroded from the Thuringian Syncline. The thickness of the Zechstein to Lower Jurassic succession is insufficient to explain the level of thermal maturity. A substantial cover of strata younger than Lower Jurassic must have been present over most of the Thuringian Syncline. The erosion of this cover must have occurred near the end of the Cretaceous period during a widespread inversion event. The pore space and the mineral surfaces exposed to the pore space of the four main facies types were studied using digital image analysis on thin sections and BET measurements. The abundance of large pores influences the permeability of a rock, as well as pore density and porosity. As a result of different types of mineral surfaces exposed to the pore space, the sandstones of the four facies types will exhibit distinctly different reactions upon contact with fluids
Continuous-wave spontaneous lasing in mercury pumped by resonant two-photon absorption
The first continuous-wave two-photon absorption laser-induced stimulated
emission (CTALISE) is demonstrated. The 7^1S-6^1P transition in mercury at
1014nm wavelength is used and selective lasing of different isotopes is
observed.Comment: 3 pages, 5 figure
Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity.
Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors
Oncological and functional outcomes after testis-sparing surgery in patients with germ cell tumors: a systematic review of 285 cases
Introduction and objectives: In several urogenital cancers, organ-preserving surgery represents the preferred treatment approach, but in patients with testicular germ cell tumors (tGCTs), radical orchiectomy represents the standard of care. This study aimed to summarize published case series assessing oncological and functional outcomes after testis-sparing surgery (TSS) in patients with tGCTs.
Materials and methods: A systematic literature review and individual patient data meta-analysis were conducted of published cases with tGCT treated with TSS.
Results: Of 2,333 reports, we included 32 reports providing data on 285 patients, including 306 testicles treated with TSS. Adjacent germ cell neoplasia in situ (GCNIS) was described in 43%. Hypogonadism and infertility after TSS were diagnosed in 27% and 18%. In patients undergoing adjuvant testicular radiotherapy, hypogonadism was diagnosed in 40%. Patients treated with adjuvant testicular radiotherapy after TSS exhibited a significantly lower incidence of local recurrence (2% vs. 50%, p < 0.001). Distant metastases after TSS were observed in 2%.
Conclusion: The current data questions the benefits of TSS in tGCT patients. If at all, TSS should only be offered to well-informed patients with a singular testicle, excellent compliance, a singular tumor less than 2 cm located at the lower pole of the testicle, and normal preoperative endocrine function. Unless patients plan to father a child within a short time frame, adjuvant testicular radiotherapy should be recommended after TSS. Radical orchiectomy remains the standard of care, but future studies may support the use of TSS in selected men.
Keywords: Systematic review; Testis cancer; Testis-sparing surgery; Urolog
Oncological and functional outcomes after testis-sparing surgery in patients with germ cell tumors: a systematic review of 285 cases.
INTRODUCTION AND OBJECTIVES
In several urogenital cancers, organ-preserving surgery represents the preferred treatment approach, but in patients with testicular germ cell tumors (tGCTs), radical orchiectomy represents the standard of care. This study aimed to summarize published case series assessing oncological and functional outcomes after testis-sparing surgery (TSS) in patients with tGCTs.
MATERIALS AND METHODS
A systematic literature review and individual patient data meta-analysis were conducted of published cases with tGCT treated with TSS.
RESULTS
Of 2,333 reports, we included 32 reports providing data on 285 patients, including 306 testicles treated with TSS. Adjacent germ cell neoplasia in situ (GCNIS) was described in 43%. Hypogonadism and infertility after TSS were diagnosed in 27% and 18%. In patients undergoing adjuvant testicular radiotherapy, hypogonadism was diagnosed in 40%. Patients treated with adjuvant testicular radiotherapy after TSS exhibited a significantly lower incidence of local recurrence (2% vs. 50%, p < 0.001). Distant metastases after TSS were observed in 2%.
CONCLUSION
The current data questions the benefits of TSS in tGCT patients. If at all, TSS should only be offered to well-informed patients with a singular testicle, excellent compliance, a singular tumor less than 2 cm located at the lower pole of the testicle, and normal preoperative endocrine function. Unless patients plan to father a child within a short time frame, adjuvant testicular radiotherapy should be recommended after TSS. Radical orchiectomy remains the standard of care, but future studies may support the use of TSS in selected men
Group-size-mediated habitat selection and group fusion-fission dynamics of bison under predation risk
For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched casecontrol design and were estimated using conditional logistic regression (mixed and populationaveraged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis that avoidance of predation risk is the strongest driver of habitat selection
Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source
Neutron total cross sections of Au and Ta have been
measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV
with a statistical uncertainty of up to 2 % and a total systematic uncertainty
of 1 %. This facility is optimized for the fast neutron energy range and
combines an excellent time structure of the neutron pulses (electron bunch
width 5 ps) with a short flight path of 7 m. Because of the low instantaneous
neutron flux transmission measurements of neutron total cross sections are
possible, that exhibit very different beam and background conditions than found
at other neutron sources.Comment: article (18 pages, 10 figures, 2 tables) with attached data tables
(13 pages
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