104 research outputs found

    Vertebral body stenting: a new method for vertebral augmentation versus kyphoplasty

    Get PDF
    Vertebroplasty and kyphoplasty are well-established minimally invasive treatment options for compression fractures of osteoporotic vertebral bodies. Possible procedural disadvantages, however, include incomplete fracture reduction or a significant loss of reduction after balloon tamp deflation, prior to cement injection. A new procedure called “vertebral body stenting” (VBS) was tested in vitro and compared to kyphoplasty. VBS uses a specially designed catheter-mounted stent which can be implanted and expanded inside the vertebral body. As much as 24 fresh frozen human cadaveric vertebral bodies (T11-L5) were utilized. After creating typical compression fractures, the vertebral bodies were reduced by kyphoplasty (n = 12) or by VBS (n = 12) and then stabilized with PMMA bone cement. Each step of the procedure was performed under fluoroscopic control and analysed quantitatively. Finally, static and dynamic biomechanical tests were performed. A complete initial reduction of the fractured vertebral body height was achieved by both systems. There was a significant loss of reduction after balloon deflation in kyphoplasty compared to VBS, and a significant total height gain by VBS (mean ± SD in %, p < 0.05, demonstrated by: anterior height loss after deflation in relation to preoperative height [kyphoplasty: 11.7 ± 6.2; VBS: 3.7 ± 3.8], and total anterior height gain [kyphoplasty: 8.0 ± 9.4; VBS: 13.3 ± 7.6]). Biomechanical tests showed no significant stiffness and failure load differences between systems. VBS is an innovative technique which allows for the possibly complete reduction of vertebral compression fractures and helps maintain the restored height by means of a stent. The height loss after balloon deflation is significantly decreased by using VBS compared to kyphoplasty, thus offering a new promising option for vertebral augmentation

    A vertex detector for the International Linear Collider based on CMOS sensors

    Get PDF
    The physics programme at the International Linear Collider (ILC) calls for a vertex detector (VD) providing unprecedented flavour tagging performances, especially for c-quarks and τ leptons. This requirement makes a very granular, thin and multi-layer VD installed very close to the interaction region mandatory. Additional constraints, mainly on read-out speed and radiation tolerance, originate from the beam background, which governs the occupancy and the radiation level the detector should be able to cope with. CMOS sensors are being developed to fulfil these requirements. This report addresses the ILC requirements (highly related to beamstrahlung), the main advantages and features of CMOS sensors, the demonstrated performances and the specific aspects of a VD based on this technology. The status of the main R&D directions (radiation tolerance, thinning procedure and read-out speed) are also presented

    Highly Active Ice‐Nucleating Particles at the Summer North Pole

    Get PDF
    The amount of ice versus supercooled water in clouds is important for their radiative properties and role in climate feedbacks. Hence, knowledge of the concentration of ice-nucleating particles (INPs) is needed. Generally, the concentrations of INPs are found to be very low in remote marine locations allowing cloud water to persist in a supercooled state. We had expected the concentrations of INPs at the North Pole to be very low given the distance from open ocean and terrestrial sources coupled with effective wet scavenging processes. Here we show that during summer 2018 (August and September) high concentrations of biological INPs (active at >−20°C) were sporadically present at the North Pole. In fact, INP concentrations were sometimes as high as those recorded at mid-latitude locations strongly impacted by highly active biological INPs, in strong contrast to the Southern Ocean. Furthermore, using a balloon borne sampler we demonstrated that INP concentrations were often different at the surface versus higher in the boundary layer where clouds form. Back trajectory analysis suggests strong sources of INPs near the Russian coast, possibly associated with wind-driven sea spray production, whereas the pack ice, open leads, and the marginal ice zone were not sources of highly active INPs. These findings suggest that primary ice production, and therefore Arctic climate, is sensitive to transport from locations such as the Russian coast that are already experiencing marked climate change

    Regulation of Human Formyl Peptide Receptor 1 Synthesis: Role of Single Nucleotide Polymorphisms, Transcription Factors, and Inflammatory Mediators

    Get PDF
    The gene encoding the human formyl peptide receptor 1 (FPR1) is heterogeneous, containing numerous single nucleotide polymorphisms (SNPs). Here, we examine the effect of these SNPs on gene transcription and protein translation. We also identify gene promoter sequences and putative FPR1 transcription factors. To test the effect of codon bias and codon pair bias on FPR1 expression, four FPR1 genetic variants were expressed in human myeloid U937 cells fused to a reporter gene encoding firefly luciferase. No significant differences in luciferase activity were detected, suggesting that the translational regulation and protein stability of FPR1 are modulated by factors other than the SNP codon bias and the variant amino acid properties. Deletion and mutagenesis analysis of the FPR1 promoter showed that a CCAAT box is not required for gene transcription. A −88/41 promoter construct resulted in the strongest transcriptional activity, whereas a −72/41 construct showed large reduction in activity. The region between −88 and −72 contains a consensus binding site for the transcription factor PU.1. Mutagenesis of this site caused significant reduction in reporter gene expression. The PU.1 binding was confirmed in vivo by chromatin immunoprecipitation, and the binding to nucleotides −84 to −76 (TTCCTATTT) was confirmed in vitro by an electrophoretic mobility shift assay. Thus, similar to many other myeloid genes, FPR1 promoter activity requires PU.1. Two single nucleotide polymorphisms at −56 and −54 did not significantly affect FPR1 gene expression, despite differences in binding of transcription factor IRF1 in vitro. Inflammatory mediators such as interferon-Îł, tumor necrosis factor-α, and lipopolysaccharide did not increase FPR1 promoter activity in myeloid cells, whereas differentiation induced by DMSO and retinoic acid enhanced the activity. This implies that the expression of FPR1 in myeloid cells is developmentally regulated, and that the differentiated cells are equipped for immediate response to microbial infections

    Correlation of gene expression and protein production rate - a system wide study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Growth rate is a major determinant of intracellular function. However its effects can only be properly dissected with technically demanding chemostat cultivations in which it can be controlled. Recent work on <it>Saccharomyces cerevisiae </it>chemostat cultivations provided the first analysis on genome wide effects of growth rate. In this work we study the filamentous fungus <it>Trichoderma reesei </it>(<it>Hypocrea jecorina</it>) that is an industrial protein production host known for its exceptional protein secretion capability. Interestingly, it exhibits a low growth rate protein production phenotype.</p> <p>Results</p> <p>We have used transcriptomics and proteomics to study the effect of growth rate and cell density on protein production in chemostat cultivations of <it>T. reesei</it>. Use of chemostat allowed control of growth rate and exact estimation of the extracellular specific protein production rate (SPPR). We find that major biosynthetic activities are all negatively correlated with SPPR. We also find that expression of many genes of secreted proteins and secondary metabolism, as well as various lineage specific, mostly unknown genes are positively correlated with SPPR. Finally, we enumerate possible regulators and regulatory mechanisms, arising from the data, for this response.</p> <p>Conclusions</p> <p>Based on these results it appears that in low growth rate protein production energy is very efficiently used primarly for protein production. Also, we propose that flux through early glycolysis or the TCA cycle is a more fundamental determining factor than growth rate for low growth rate protein production and we propose a novel eukaryotic response to this i.e. the lineage specific response (LSR).</p
    • 

    corecore