Fast jets from bubbles close to solid objects: examples from pillars in water to infinite planes in different liquids

The dynamics of a single, laser-induced cavitation bubble on top of a solid cylinder and right at a plane solid boundary is studiedboth experimentally and numerically. The most intriguing phenomenon that occurs for a millimeter sized bubble right at a flatsolid boundary in water is the formation of a fast jet that is directed towards the solid with a speed of the order of 1000 m/s.Paradoxically, in this setting, fast jet formation causally is related to the viscosity of the liquid.Thus, results from numericalsimulations with varying liquid viscosity and bubble size are presented. Bubble dynamics and jet formation mechanisms arediscussed. It is shown, that fast jet formation persists for a wide range of liquid viscosities, including e.g. 50 cSt silicone oil. Forbubbles generated close to the flat top of a long, thin cylinder the parameter space of initial distance to the cylinder, bubble size andcylinder radius is scanned numerically and partly compared to experiments. When the maximum radius of the bubble exceeds theone of the cylinder the bubble collapses in the form of a mushroom or can resemble a trophy, depending on the values of thegeometry parameters. Complex patterns of jet formation with jet speeds ranging from the order of a few hundred m/s to severalthousand m/s are found.The results represent a contribution to understand the behavior of bubbles collapsing close to solid surfaces,in particular, how thin, fast jets are generated

Perilla Extract improves gastrointestinal discomfort in a randomized placebo controlled double blind human pilot study

BACKGROUND: Gastrointestinal (GI) discomfort, e.g. bloating or rumbling, is a common symptom in otherwise healthy adults. Approximately 20% of the population, particularly women suffer from gastrointestinal discomfort and this affects quality of life. Recent studies discovered a link between the body and mind, called the gut-brain axis. Psychosocial factors, such as e.g. daily stress may cause altered gut physiology leading to ileum contractions and consequently gastrointestinal symptoms. In vitro and ex vivo studies clearly showed that a Perilla frutescens extract combines prokinetic, antispasmodic and anti-inflammatory effects. The aim of the intervention was to investigate the effects of the proprietary Perilla extract on GI discomfort in healthy subjects with gastrointestinal discomfort and reduced bowel movements in comparison to a placebo product. METHODS: The pilot study was performed according to a double-blind, randomized, placebo-controlled parallel design. Fifty healthy subjects with gastrointestinal discomfort and reduced bowel movements, 30-70 years, documented their GI symptoms, stool frequency and consistency daily during a 2-week run-in phase and a 4-week intervention phase with Perilla frutescens extract or placebo. GI symptoms were assessed on a 5-point scale daily and average scores over 14 days intervals were calculated. RESULTS: All GI symptoms were significantly improved over time by Perilla frutescens extract during the intervention phase (bloating: -0.44 ± 0.56, p = 0.0003; passage of gas: -0.30 ± 0.66, p = 0.0264; GI rumbling: -0.55 ± 0.87, p = 0.0014; feeling of fullness: -0.36 ± 0.72, p = 0.0152; abdominal discomfort: -0.54 ± 0.75, p = 0.004), whereas in the placebo group only abdominal discomfort was significantly improved (-0.31 ± 0.55, p = 0.0345). In the subgroup of women results were strengthened and a subscore out of bloating and abdominal discomfort was significantly improved against placebo (95%CI 0.003 to 0.77; p = 0.048). CONCLUSION: The demonstrated effects of Perilla frutescens extract to improve GI complaints offer very promising results, taking into consideration the challenging set up of a nutritional human study with healthy subjects and in the area of digestive health, which is known for high placebo effects. TRIAL REGISTRATION NUMBER: NCT01931930 at ClinicalTrials.gov, Registration date 23(rd) August 2013

Transcriptional Targeting of B Cells for Induction of Peripheral CD8 T Cell Tolerance

Abstract Several mechanisms are in place to neutralize autoimmune CD8 T cells by tolerance induction. Developing self-specific CD8 T cells are eliminated in the thymus by Ag-presenting epithelial and dendritic cells (DCs). However, CD8 T cells escaping thymic central tolerance can also be inactivated by tolerance mechanisms in peripheral organs. In contrast to DCs, the role of B cells in generating CD8 T cell tolerance is not well-characterized. To investigate this question in more detail, we transcriptionally targeted Ag to B cells using B cell-specific retroviral vectors in vivo. Although Ag expression could be detected in B cells of thymus, lymph nodes, and spleen, B cells were unable to induce central tolerance of CD8 thymocytes. In contrast, in peripheral organs, we could identify clonal deletion and functional inhibition (anergy) of CD8 T cells as tolerance-inducing mechanisms. Although Ag expressed by B cells was acquired and cross-presented by DCs, B cells were also sufficient to tolerize CD8 T cells directly. These findings suggest exploitation of B cells for Ag-specific immunotherapy of CD8 T cell-mediated autoimmune diseases

Baculovirus-Mediated Expression of Human 65 kDa and 67 kDa Glutamic Acid Decarboxylases in SF9 Insect Cells and Their Relevance in Diagnosis of Insulin-Dependent Diabetes Mellitus

cDNAs coding for the full-length human 65 and 67 kDa glutamic acid decarboxylases (GAD65 and GAD67) were amplified from pancreas and hippocampus cDNA libraries by polymerase chain reaction, respectively. Both cDNAs were inserted into a baculovirus vector which mediated highly efficient expression of the human GAD65 and GAD67 with histidine-hexapeptides as affinity ligands at their C-termini in Spodoptera frugiperda (Sf9) cells. The recombinant GAD proteins were purified to homogeneity by affinity chromatography using a metal-chelating matrix. The infected Sf9 insect cells expressed the recombinant human GAD65 and GAD67 with natural-like conformations, as confirmed by measurement of their enzyme activities as well as their fully restored autoantigenicities. Immunoprecipitation of metabolically labeled infected Sf9 cells demonstrated the autoantigenic potential of the recombinant GAD proteins. The practicability of using recombinant GAD65 and GAD67 derived from the baculovirus expression system for the development of an immunoassay for the diagnosis of insulin-dependent diabetes mellitus is discussed