study protocol for a randomized controlled trial

Background For the surgical treatment of recurrent primary spontaneous pneumothoraces (rPSP) different operative therapies are applied to achieve permanent freedom from recurrence. Methods/design This multicenter clinical trial evaluates the long-term results of two commonly applied surgical techniques for the treatment of rPSP. Based on the inclusion and exclusion criteria, and after obtaining the patients’ informed consent, participants are randomized into the two surgical treatment arms: pulmonary wedge resection plus parietal pleurectomy (WRPP) or parietal pleurectomy alone (PP). Consecutively, all study participants will be followed up for two years to evaluate the surgical long-term effect. The primary efficacy endpoint is the recurrence rate of pneumothorax within 24 months after surgery. The calculated sample size is 360 patients (n = 180 per treatment arm) to prove superiority of one of the two treatments. So far, 22 surgical sites have submitted their declaration of commitment, giving the estimated number of participating patients. Discussion A prospective randomized clinical trial has been started to compare two established surgical therapies to evaluate the long-term results regarding recurrence rates. Furthermore, cost of treatment, and influence on the perioperative morbidity and mortality as well as on quality of life are analyzed. If the study reveals equivalence for both surgical techniques, unnecessary pulmonary resections could be avoided

Influence of Cooling Parameters on the Surface Layer Structure of Hot Working Tools

The surface layer of hot working tools is subject to alternating thermo-mechanical loads during forging. It experiences a fast increase in temperature on contact with the heated billets, followed by a steep temperature decline during application of the spray-coolant. This can lead to a cyclic surface rehardening of the tool surface layer due to the formation of a martensitic structure, which can either delay or accelerate tool failure. The microstructural changes in the tool surface layer mainly depend on the thermal, mechanical and tribological loads during forging. The influence of these loads is of particular interest to understand the effect of cyclic surface rehardening. The goal of this research is to investigate the influence of cooling parameters on microstructural changes in the tool surface layer during die forging. Mechanical and tribological loads are kept constant while cooling parameters are varied. Three internal thermocouples are applied to forging tools to measure the base tool temperature. To keep the amount of lubricant in each forging cycle at constant levels, cooling and lubrication are separated by use of boron nitride as lubricant, which is applied by electrostatic adherence. For cooling, the duration of water application is varied while maintaining pressure and spray pattern. Fourtools with differenttool base temperatures are investigated and the influence of the thermal loads on the wear behaviour displayed

Design of a forging process to individually examine thermal, mechanical and tribological stress in the tool surface zone

The surface layer of hot forging tools undergoes local microstructural changes due to high thermo-mechanical and tribological loads. Tools made of hot working steel are usually preheated and experience extreme heating and cooling during each forging cycle, affecting their local wear behaviour significantly. Therefore, the analysis of these tool surface layers in die forging and their effect on wear behaviour is of great importance. The microstructural changes in the tool surface layer mainly depend on thermal loads, which are highly influenced by the tool cooling system. A process and a suitable tool system are developed to vary the thermal and mechanical loads on the tool surface layer and fundamentally examine the resulting microstructural changes

Airborne bacterial emission fluxes from manure-fertilized agricultural soil

This is the first study to quantify the dependence on wind velocity of airborne bacterial emission fluxes from soil. It demonstrates that manure bacteria get aerosolized from fertilized soil more easily than soil bacteria, and it applies bacterial genomic sequencing for the first time to trace environmental faecal contamination back to its source in the chicken barn. We report quantitative, airborne emission fluxes of bacteria during and following the fertilization of agricultural soil with manure from broiler chickens. During the fertilization process, the concentration of airborne bacteria culturable on blood agar medium increased more than 600 000-fold, and 1 m(3)of air carried 2.9 x 10(5)viable enterococci, i.e. indicators of faecal contamination which had been undetectable in background air samples. Trajectory modelling suggested that atmospheric residence times and dispersion pathways were dependent on the time of day at which fertilization was performed. Measurements in a wind tunnel indicated that airborne bacterial emission fluxes from freshly fertilized soil under local climatic conditions on average were 100-fold higher than a previous estimate of average emissions from land. Faecal bacteria collected from soil and dust up to seven weeks after fertilization could be traced to their origins in the poultry barn by genomic sequencing. Comparative analyses of 16S rRNA gene sequences from manure, soil and dust showed that manure bacteria got aerosolized preferably, likely due to their attachment to low-density manure particles. Our data show that fertilization with manure may cause substantial increases of bacterial emissions from agricultural land. After mechanical incorporation of manure into soil, however, the associated risk of airborne infection is low

Agricultural fertilization with poultry manure results in persistent environmental contamination with the pathogen Clostridioides difficile

During a field experiment applying broiler manure for fertilization of agricultural land, we detected viable Clostridioides (also known as Clostridium) difficile in broiler faeces, manure, dust and fertilized soil. A large diversity of toxigenic C. difficile isolates was recovered, including PCR ribotypes common from human disease. Genomic relatedness of C. difficile isolates from dust and from soil, recovered more than 2 years after fertilization, traced their origins to the specific chicken farm that had delivered the manure. We present evidence of long-term contamination of agricultural soil with manure-derived C. difficile and demonstrate the potential for airborne dispersal of C. difficile through dust emissions during manure application. Clostridioides genome sequences virtually identical to those from manure had been recovered from chicken meat and from human infections in previous studies, suggesting broiler-associated C. difficile are capable of zoonotic transmission

On-tissue dataset-dependent MALDI-TIMS-MS2^{2} bioimaging

Trapped ion mobility spectrometry (TIMS) adds an additional separation dimension to mass spectrometry (MS) imaging, however, the lack of fragmentation spectra (MS$^{2}$) impedes confident compound annotation in spatial metabolomics. Here, we describe spatial ion mobility-scheduled exhaustive fragmentation (SIMSEF), a dataset-dependent acquisition strategy that augments TIMS-MS imaging datasets with MS$^{2}$ spectra. The fragmentation experiments are systematically distributed across the sample and scheduled for multiple collision energies per precursor ion. Extendable data processing and evaluation workflows are implemented into the open source software MZmine. The workflow and annotation capabilities are demonstrated on rat brain tissue thin sections, measured by matrix-assisted laser desorption/ionisation (MALDI)-TIMS-MS, where SIMSEF enables on-tissue compound annotation through spectral library matching and rule-based lipid annotation within MZmine and maps the (un)known chemical space by molecular networking. The SIMSEF algorithm and data analysis pipelines are open source and modular to provide a community resource

Bone marrow mesenchymal stromal cell-derived extracellular matrix displays altered glycosaminoglycan structure and impaired functionality in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of hematologic malignancies characterized by clonal hematopoiesis, one or more cytopenias such as anemia, neutropenia, or thrombocytopenia, abnormal cellular maturation, and a high risk of progression to acute myeloid leukemia. The bone marrow microenvironment (BMME) in general and mesenchymal stromal cells (MSCs) in particular contribute to both the initiation and progression of MDS. However, little is known about the role of MSC-derived extracellular matrix (ECM) in this context. Therefore, we performed a comparative analysis of in vitro deposited MSC-derived ECM of different MDS subtypes and healthy controls. Atomic force microscopy analyses demonstrated that MDS ECM was significantly thicker and more compliant than those from healthy MSCs. Scanning electron microscopy showed a dense meshwork of fibrillar bundles connected by numerous smaller structures that span the distance between fibers in MDS ECM. Glycosaminoglycan (GAG) structures were detectable at high abundance in MDS ECM as white, sponge-like arrays on top of the fibrillar network. Quantification by Blyscan assay confirmed these observations, with higher concentrations of sulfated GAGs in MDS ECM. Fluorescent lectin staining with wheat germ agglutinin and peanut agglutinin demonstrated increased deposition of N-acetyl-glucosamine GAGs (hyaluronan (HA) and heparan sulfate) in low risk (LR) MDS ECM. Differential expression of N-acetyl-galactosamine GAGs (chondroitin sulfate, dermatan sulfate) was observed between LR- and high risk (HR)-MDS. Moreover, increased amounts of HA in the matrix of MSCs from LR-MDS patients were found to correlate with enhanced HA synthase 1 mRNA expression in these cells. Stimulation of mononuclear cells from healthy donors with low molecular weight HA resulted in an increased expression of various pro-inflammatory cytokines suggesting a contribution of the ECM to the inflammatory BMME typical of LR-MDS. CD34+ hematopoietic stem and progenitor cells (HSPCs) displayed an impaired differentiation potential after cultivation on MDS ECM and modified morphology accompanied by decreased integrin expression which mediate cell-matrix interaction. In summary, we provide evidence for structural alterations of the MSC-derived ECM in both LR- and HR-MDS. GAGs may play an important role in this remodeling processes during the malignant transformation which leads to the observed disturbance in the support of normal hematopoiesis

Airborne bacterial emission fluxes from manure-fertilized agricultural soil

This is the first study to quantify the dependence on wind velocity of airborne bacterial emission fluxes from soil. It demonstrates that manure bacteria get aerosolized from fertilized soil more easily than soil bacteria, and it applies bacterial genomic sequencing for the first time to trace environmental faecal contamination back to its source in the chicken barn. We report quantitative, airborne emission fluxes of bacteria during and following the fertilization of agricultural soil with manure from broiler chickens. During the fertilization process, the concentration of airborne bacteria culturable on blood agar medium increased more than 600 000-fold, and 1 m3 of air carried 2.9 × 105 viable enterococci, i.e. indicators of faecal contamination which had been undetectable in background air samples. Trajectory modelling suggested that atmospheric residence times and dispersion pathways were dependent on the time of day at which fertilization was performed. Measurements in a wind tunnel indicated that airborne bacterial emission fluxes from freshly fertilized soil under local climatic conditions on average were 100-fold higher than a previous estimate of average emissions from land. Faecal bacteria collected from soil and dust up to seven weeks after fertilization could be traced to their origins in the poultry barn by genomic sequencing. Comparative analyses of 16S rRNA gene sequences from manure, soil and dust showed that manure bacteria got aerosolized preferably, likely due to their attachment to low-density manure particles. Our data show that fertilization with manure may cause substantial increases of bacterial emissions from agricultural land. After mechanical incorporation of manure into soil, however, the associated risk of airborne infection is low

Agricultural fertilization with poultry manure results in persistent environmental contamination with the pathogen Clostridioides difficile

During a field experiment applying broiler manure for fertilization of agricultural land, we detected viable Clostridioides (also known as Clostridium) difficile in broiler faeces, manure, dust and fertilized soil. A large diversity of toxigenic C. difficile isolates was recovered, including PCR ribotypes common from human disease. Genomic relatedness of C. difficile isolates from dust and from soil, recovered more than 2 years after fertilization, traced their origins to the specific chicken farm that had delivered the manure. We present evidence of long-term contamination of agricultural soil with manure-derived C. difficile and demonstrate the potential for airborne dispersal of C. difficile through dust emissions during manure application. Clostridioides genome sequences virtually identical to those from manure had been recovered from chicken meat and from human infections in previous studies, suggesting broiler-associated C. difficile are capable of zoonotic transmission