21 research outputs found
Author Correction: Early pregnancy ultrasound measurements and prediction of first trimester pregnancy loss: A logistic model
No full textThe original version of this Article contained an error in the spelling of the author Patricia J. Goedecke which was incorrectly given as Patricia J. Goeske. The original Article has been corrected
Analysis of microplastics in theory and in practice
No full textDue to the favorable properties of polymers, their production and thus their input into the environment has increased significantly in recent decades. Currently, FTIR or Raman spectroscopy are mainly applied for the analysis of microplastic particles (MP) in environmental samples. However, these methods have great difficulties in determining metrologically traceable MP values, especially with regard to the limiting values, as preferred in regulation. Therefore, we developed a systematic and fast thermoanalytical method called TED-GC-MS (thermal extraction desorption gas chromatography mass spectrometry), which determines mass contents. Now the current goal is the determination of its process parameters.
This poster illustrates the theoretical requirements for MP analysis (left side) and contrast them with the current state of research (right side).Unexpected practical problems are presented and the relatively new method is discussed concerning the quality requirements of well-established methods such as LC-or GC-MS
Detection of microplastics in compost samples using a thermal decomposition method
No full textThe ubiquitous presence of unwanted plastics in the environment, especially microscale particles, has been an issue in scientific studies and public debate in the last years. It is well known that oxidative degradation and subsequent fragmentation, caused by UV-radiation, oxidative aging and abrasion lead to the decomposition of larger plastic products into microplastics (MP). Possible effects of these MP on ecosystems are still unclear. Recent studies on MP findings are focused mainly on aquatic systems, while little is known about MP in terrestrial ecosystems.
A possible source of MP input into the soil is compost from domestic bio-waste. Inappropriate waste separation causes plastic fragments in the bio-waste, some of which end up in the compost. In Germany compost is used as fertilizer in agriculture, hence MP could enter the soil by this pathway. So far, there have been only a few studies on this object. For this reason, analysis of compost as a sink and source of MP in ecosystems is of high interest.
To estimate and monitor the MP content in compost and soil, fast and harmonised analytical methods are essential, which not only measure the polymer type and number of particles, but also the mass content. The most common spectroscopic methods are very time-consuming, often require complex sample preparation steps and cannot determine mass contents. Therefore, we used ThermoExtractionDesorption-GasChromatography-MassSpectrometry (TED-GC-MS) as a fast, integral analytical technique. The sample is pyrolyzed to 600°C in a nitrogen atmosphere and an excerpt of the pyrolysis gases is collected on a solid phase adsorber. Afterwards, the decomposition gases are desorbed and measured in a GC-MS system. Characteristic pyrolysis products can be used to identify the polymer type and determine the mass contents. This method is well established for the analysis of MP in water filtrate samples.
In the present work we optimized the TED-GC-MS method for compost and compost/soil matrix and very common polymers, such as polyethylene, polypropylene, polyethylene-terephthalate and polystyrene (sample mass, detection limits, interfering signals, etc.). Additionally, specific pyrolysis products of polymers used for bio-waste bags, such as polylactide (PLA) and polybutylenadipat-terephthalat (PBAT) had to be identified and evaluated.
First measurements were carried out on model and real samples from prepared mixtures and composting plant. The samples were sterilized, fractionated, filtered and dried. In addition, half of the sample material was treated with hydrogen peroxide to investigate a possible effect on detection
Making Friends : Constructions of Change, Masculine Positions and Friendships Among Former Drug Users
No full textMany facets of relationality are explored in this chapter, which highlights meaning-makings around men’s friendships, processes of change – relating a perceived “new” self to an “old” one – and the relationship between interviewer and interviewee. The author explores narratives of friendship among a group of young men involved in exit processes, leaving a life of crime and drug-abuse and starting to build a non-criminal and non-drug abusing life. The chapter is based on interviews and the performative aspects of the interview situation are underscored; thus, talking about changing one’s life can be understood as performing or doing change(dness) during the interview. The interviewees’ narratives of themselves and their friendships are structured by turning-points and temporal dichotomies, where “now” is separated from “then”, and “new” from “old”. A new, caring, communicative self who is capable of having real friends is contrasted against an old, violent, manipulative, aggressive and friendless self. Arguing that one is capable of to uphold “real friendship” is vital when positioning as changed during the interview, and the author argues that this is a part of a dramatic reorientation in the men’s masculinity projects, which can be understood in relation to ideas of Swedishness, gender-equality and “new”, caring masculinities.</p
Men’s Friendships as Feminist Politics? Power, Intimacy, and Change
No full textThis book discusses men’s friendships in relation to queer, discursive, and intersectional feminist theories. It analyses stories of intimacy, touch, hugs, and conversations, connecting these with current discussions within feminism and critical masculinity studies on “new” men, men’s political activism, and how friendships are lived and conceptualised in relation to heteronormative relationship ideals. Drawing on individual and dyadic interviews with middle-class Swedish men, all engaged in or sympathetic to feminist issues in some sense, this volume shows that Swedish gender equality ideologies as well as feminist, therapeutic, neo-liberal, and individualist discourses prevalent in the Western world structured the men’s friendships and their engagement with gender politics. Chapters cover friendship temporalities, gendered friendship ideals, friendship as men’s politics, and friendship as performed in interaction. Bridging the literatures of feminist research and friendship, the author points to tensions and contradictions in pro-feminist men’s political projects and in contemporary masculine positions.</p
Modification of Loop 1 Affects the Nucleotide Binding Properties of Myo1c, the Adaptation Motor in the Inner Ear
No full textMyo1c is one of eight members of the mammalian myosin I family of actin-associated molecular motors. In stereocilia of the hair cells in the inner ear, Myo1c presumably serves as the adaptation motor, which regulates the opening and closing of transduction channels. Although there is conservation of sequence and structure among all myosins in the N-terminal motor domain, which contains the nucleotide- and actin-binding sites, some differences include the length and composition of surface loops, including loop 1, which lies near the nucleotide-binding domain. To investigate the role of loop 1, we expressed in insect cells mutants of a truncated form of Myo1c, Myo1c1IQ, as well as chimeras of Myo1c1IQ with the analogous loop from other myosins. We found that replacement of the charged residues in loop 1 with alanines or the whole loop with a series of alanines did not alter the ATPase activity, transient kinetics properties, or Ca2+ sensitivity of Myo1c1IQ. Substitution of loop 1 with that of the corresponding region from tonic smooth muscle myosin II (Myo1c1IQ-tonic) or replacement with a single glycine (Myo1c1IQ-G) accelerated the release of ADP from A.M 2?3-fold in Ca2+, whereas substitution with loop 1 from phasic muscle myosin II (Myo1c1IQ-phasic) accelerated the release of ADP 35-fold. Motility assays with chimeras containing a single ?-helix, or SAH, domain showed that Myo1cSAH-tonic translocated actin in vitro twice as fast as Myo1cSAH-WT and 3-fold faster than Myo1cSAH-G. The studies show that changes induced in Myo1c via modification of loop 1 showed no resemblance to the behavior of the loop donor myosins or to the changes previously observed with similar Myo1b chimeras
Microplastic analysis using chemical extraction followed by LC-UV analysis: a straightforward approach to determine PET content in environmental samples
No full textBackground: The ubiquitous occurrence of microplastic particles in marine and aquatic ecosystems was intensively investigated in the past decade. However, we know less about the presence, fate, and input paths of microplastic in terrestrial ecosystems. A possible entry path for microplastic into terrestrial ecosystems is the agricultural application of sewage sludge and solid bio-waste as fertilizers. Microplastic contained in sewage sludge also includes Polyethylene terephthalate (PET), which could originate as fiber from textile products or as a fragment from packaging products (foils, bottles, etc.). Information about microplastic content in such environmental samples is limited yet, as most of the used analytical methods are very time-consuming, regarding sample preparation and detection, require sophisticated analytical tools and eventually need high user knowledge.
Results: Here, we present a simple, specific tool for the analysis of PET microplastic particles based on alkaline extraction of PET from the environmental matrix and subsequent determination of the monomers, terephthalic acid, using liquid chromatography with UV detection (LC-UV). The applicability of the method is shown for different types of PET in several soil-related, terrestrial environmental samples, e.g., soil, sediment, compost, fermentation residues, but also sewage sludge, suspended particles from urban water management systems, and indoor dust. Recoveries for model samples are between 94.5 and 107.1%. Limit of determination and limit of quantification are absolute masses of 0.031 and 0.121 mg PET, respectively. In order to verify the measured mass contents of the environmental samples, a method comparison with thermal extraction-desorption-gas chromatography–mass spectrometry (TED-GC/MS) was conducted. Both methods deliver similar results and corroborated each other. PET mass contents in environmental samples range from values below LOQ in agriculture soil up to 57,000 mg kg−1 in dust samples.
Conclusions: We demonstrate the potential of an integral method based on chemical extraction for the Determination of PET mass contents in solid environmental samples. The method was successfully applied to various matrices and may serve as an analytical tool for further investigations of PET-based microplastic in terrestrial ecosystems
Alternative Exon 9-Encoded Relay Domains Affect More than One Communication Pathway in the Drosophila Myosin Head
No full textWe investigated the biochemical and biophysical properties of one of the four alternative regions within the Drosophila myosin catalytic domain: the relay domain encoded by exon 9. This domain of the myosin head transmits conformational changes in the nucleotide-binding pocket to the converter domain, which is crucial to coupling catalytic activity with mechanical movement of the lever arm. To study the function of this region, we used chimeric myosins (IFI-9b and EMB-9a), which were generated by exchange of the exon 9-encoded domains between the native embryonic body wall (EMB) and indirect flight muscle isoforms (IFI). Kinetic measurements show that exchange of the exon 9-encoded region alters the kinetic properties of the myosin S1 head. This is reflected in reduced values for ATP-induced actomyosin dissociation rate constant (K(1)k(+2)) and ADP affinity (K(AD)), measured for the chimeric constructs IFI-9b and EMB-9a, compared to wild-type IFI and EMB values. Homology models indicate that, in addition to affecting the communication pathway between the nucleotide-binding pocket and the converter domain, exchange of the relay domains between IFI and EMB affects the communication pathway between the nucleotide-binding pocket and the actin-binding site in the lower 50-kDa domain (loop 2). These results suggest an important role of the relay domain in the regulation of actomyosin cross-bridge kinetics
Avaliação das alterações da saturação periférica de oxigênio, da tensão arterial e do pulso em pacientes submetidos à sedação consciente para endoscopia digestiva alta
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Dapartamento de Clínica Cirúrgica
Global Drivers of Land Degradation and Improvement
No full text© The Editor(s) (if applicable) and The Author(s) 2016. Identification of factors catalyzing sustainable land management (SLM) could provide insights for national policies and international efforts to address land degradation. Building on previous studies, and using novel datasets, this chapter identifies major drivers of land degradation at global and regional levels. The findings of this study confirm the earlier insights in the literature on the context-specific nature of the drivers of land degradation. This context-dependence explains the previous contradictions in the literature on the effects of various socio-economic and institutional factors on land degradation. It also calls for the localized diagnostic of the drivers of land degradation. The drivers of land degradation are predominantly local, so actions to address them should be based on the understanding of the local interplay of various factors and how they affect land degradation.status: Publishe
