Metrology in Chemistry for pH and Electrolytic Conductivity Traceability Dissemination

pH and electrolytic conductivity are important metrological quantities for several areas of industry. To get reliable results it is necessary to calibrate measuring instruments and devices regularly. For this purpose certified reference solutions are needed. DKD-K-06901 is a manufacturer of certified reference solutions and offers calibration services in the field of analytical chemistry. There are three accredited calibration procedures for the determination of pH used by ZKM - ANALYTIK - GmbH. A new calibration procedure for electrolytic conductivity was established by experts in DKD-K-06901 as the result of a development project in cooperation with National Metrology Institutes. The validation of all procedures is guaranteed by the participation in national and international comparison measurements. Furthermore DKD-K-06901 is actively involved in the work of technical and standardisation committees for developments of analytical quantities

A Surfactant Enables Efficient Membrane Spanning by Non-Aggregating DNA-Based Ion Channels.

Funder: Friedrich Naumann FoundationFunder: Cambridge Philosophical SocietyFunder: Winton Programme for the Physics of SustainabilityFunder: Jane Bourque-Driscoll FundDNA nanotechnology makes use of hydrophobically modified constructs to create synthetic membrane protein mimics. However, nucleic acid structures exhibit poor insertion efficiency, leading to a low activity of membrane-spanning DNA protein mimics. It is suggested that non-ionic surfactants improve insertion efficiency, partly by disrupting hydrophobicity-mediated clusters. Here, we employed confocal microscopy and single-molecule transmembrane current measurements to assess the effects of the non-ionic surfactant octylpolyoxyethylene (oPOE) on the clustering behavior and membrane activity of cholesterol-modified DNA nanostructures. Our findings uncover the role of aggregation in preventing bilayer interactions of hydrophobically decorated constructs, and we highlight that premixing DNA structures with the surfactant does not disrupt the cholesterol-mediated aggregates. However, we observed the surfactant's strong insertion-facilitating effect, particularly when introduced to the sample separately from DNA. Critically, we report a highly efficient membrane-spanning DNA construct from combining a non-aggregating design with the addition of the oPOE surfactant.DM acknowledges funding from the Winton Programme for the Physics of Sustainability and the Engineering and Physical Sciences Research Council (EPSRC, project ref. 1948702). MS acknowledges funding from the Friedrich Naumann Foundation, the Jane Bourque-Driscoll Fund and the Cambridge Philosophical Society. UFK acknowledges the ERC Consolidator Grant (De-signer-Pores 647144)

Characterization of lipid composition and diffusivity in OLA generated vesicles.

Giant Unilamellar Vesicles (GUVs) are a versatile tool in many branches of science, including biophysics and synthetic biology. Octanol-Assisted Liposome Assembly (OLA), a recently developed microfluidic technique enables the production and testing of GUVs within a single device under highly controlled experimental conditions. It is therefore gaining significant interest as a platform for use in drug discovery, the production of artificial cells and more generally for controlled studies of the properties of lipid membranes. In this work, we expand the capabilities of the OLA technique by forming GUVs of tunable binary lipid mixtures of DOPC, DOPG and DOPE. Using fluorescence recovery after photobleaching we investigated the lateral diffusion coefficients of lipids in OLA liposomes and found the expected values in the range of 1 μm2/s for the lipid systems tested. We studied the OLA derived GUVs under a range of conditions and compared the results with electroformed vesicles. Overall, we found the lateral diffusion coefficients of lipids in vesicles obtained with OLA to be quantitatively similar to those in vesicles obtained via traditional electroformation. Our results provide a quantitative biophysical validation of the quality of OLA derived GUVs, which will facilitate the wider use of this versatile platform.Friedrich Naumann Foundation; Jane Bourque-Driscoll Fund; Cambridge Philosophical Society; Winton Programme for the Physics of Sustainability; Engineering and Physical Sciences Research Council; Wellcome Trust; ER

Glucocorticoids Equally Stimulate Epithelial Na+ Transport in Male and Female Fetal Alveolar Cells

Preterm infants frequently suffer from respiratory distress syndrome (RDS), possibly due to lower expression of epithelial Na+ channels (ENaC). RDS incidence is sex-specific, affecting males almost twice as often. Despite the use of antenatal glucocorticoids (GCs), the sex difference persists. It is still controversial whether both sexes benefit equally from GCs. We previously showed that Na+ transport is higher in female compared with male fetal distal lung epithelial (FDLE) cells. Since GCs increase Na+ transport, we hypothesized that their stimulating effect might be sex-specific. We analyzed FDLE cells with Ussing chambers and RT-qPCR in the presence or absence of fetal serum. In serum-free medium, GCs increased the ENaC activity and mRNA expression, independent of sex. In contrast, GCs did not increase the Na+ transport in serum-supplemented media and abolished the otherwise observed sex difference. Inhibition of the GC receptor in the presence of serum did not equalize Na+ transport between male and female cells. The GC-induced surfactant protein mRNA expression was concentration and sex-specific. In conclusion, female and male FDLE cells exhibit no sex difference in response to GCs with regard to Na+ transport, and GR activity does not contribute to the higher Na+ transport in females

Tailoring Interleaflet Lipid Transfer with a DNA-based Synthetic Enzyme.

Lipid membranes, enveloping all living systems, are of crucial importance, and control over their structure and composition is a highly desirable functionality of artificial structures. However, the rational design of protein-inspired systems is still challenging. Here we have developed a highly functional nucleic acid construct that self-assembles and inserts into membranes, enabling lipid transfer between inner and outer leaflets. By designing the structure to account for interactions between the DNA, its hydrophobic modifications, and the lipids, we successfully exerted control over the rate of interleaflet lipid transfer induced by our DNA-based enzyme. Furthermore, we can regulate the level of lipid transfer by altering the concentration of divalent ions, similar to stimuli-responsive lipid-flipping proteins

Enzyme-mediated surface functionalisation of stimuli-responsive microgels

Aqueous microgels based on N-Vinylcaprolactam (VCL) gained much attention in the biomedical research due to their temperature-sensitive behavior and their high biocompatibility.[1] However, the post-modification of PVCL-microgels with proteins is still challenging. The so-called sortase-mediated ligation is one possible method for the conjugation of biomolecules to polymers.[2] Sortases are bacterial enzymes with transpeptidase activity, responsible for the attachment of proteins to the cell wall of gram-positive bacteria. Sortases of class A (SrtA) recognize a LPXTG-sorting motif (X being any amino acid) at the C-terminus of the targeted protein, cleave it between the threonine and the glycine and ligate it to a second protein via an oligoglycine nucleophile.[3] In this work, we present the use of sortase-mediated ligation for the conjugation of different proteins to PVCL-microgels with the aim to incorporate special functionalities. For this purpose, microgels based on PVCL containing 5 mol% glycidyl methacrylate (GMA) as comonomer in the particles shell were synthesized and modified with the specific recognition peptide sequence LPETG for SrtA. The coupling of the LPETG sequence was analyzed via UV-Vis spectroscopy and Raman spectroscopy. To perform Sortase-mediated ligation, oligoglycin-tagged enhanced Green Fluorescent Protein (GGG‑eGFP) was used as a model protein. The conjugation of the eGFP to the microgel was investigated qualitatively via confocal microscopy and quantitatively via fluorescence intensity measurements. It was shown that the fluorescence intensity increased linearly with increasing eGFP-concentration and exponentially with increasing reaction time up to seven hours. Additionally, we were able to show that also oligoglycin-tagged CueO-laccase can be conjugated to the PVCL-microgel using sortase-mediated ligation. To this end, the protein activity of the microgels was measured using ABTS as laccase substrate and the amount of conjugated protein was analyzed via BCA assay. These results indicate that sortase-mediated ligation is a very promising and powerful tool for the modification of microgels with biomacromolecules for applications in drug delivery, biointerface coatings and sensors. Aqueous microgels based on N-Vinylcaprolactam (VCL) gained much attention in the biomedical research due to their temperature-sensitive behavior and their high biocompatibility.[1] However, the post-modification of PVCL-microgels with proteins is still challenging. The so-called sortase-mediated ligation is one possible method for the conjugation of biomolecules to polymers.[2] Sortases are bacterial enzymes with transpeptidase activity, responsible for the attachment of proteins to the cell wall of gram-positive bacteria. Sortases of class A (SrtA) recognize a LPXTG-sorting motif (X being any amino acid) at the C-terminus of the targeted protein, cleave it between the threonine and the glycine and ligate it to a second protein via an oligoglycine nucleophile.[3] In this work, we present the use of sortase-mediated ligation for the conjugation of different proteins to PVCL-microgels with the aim to incorporate special functionalities. For this purpose, microgels based on PVCL containing 5 mol% glycidyl methacrylate (GMA) as comonomer in the particles shell were synthesized and modified with the specific recognition peptide sequence LPETG for SrtA. The coupling of the LPETG sequence was analyzed via UV-Vis spectroscopy and Raman spectroscopy. To perform Sortase-mediated ligation, oligoglycin-tagged enhanced Green Fluorescent Protein (GGG‑eGFP) was used as a model protein. The conjugation of the eGFP to the microgel was investigated qualitatively via confocal microscopy and quantitatively via fluorescence intensity measurements. It was shown that the fluorescence intensity increased linearly with increasing eGFP-concentration and exponentially with increasing reaction time up to seven hours. Additionally, we were able to show that also oligoglycin-tagged CueO-laccase can be conjugated to the PVCL-microgel using sortase-mediated ligation. To this end, the protein activity of the microgels was measured using ABTS as laccase substrate and the amount of conjugated protein was analyzed via BCA assay. These results indicate that sortase-mediated ligation is a very promising and powerful tool for the modification of microgels with biomacromolecules for applications in drug delivery, biointerface coatings and sensors. Please click Additional Files below to see the full abstract

s-ICAM-1 and s-VCAM-1 in healthy men are strongly associated with traits of the metabolic syndrome, becoming evident in the postprandial response to a lipid-rich meal

<p>Abstract</p> <p>Background</p> <p>The importance of the postprandial state for the early stages of atherogenesis is increasingly acknowledged. We conducted assessment of association between postprandial triglycerides, insulin and glucose after ingestion of a standardized lipid-rich test meal, and soluble cellular adhesion molecules (sCAM) in young healthy subjects.</p> <p>Methods</p> <p>Metabolic parameters and sICAM-1, sVCAM-1 and E-selectin were measured before and hourly until 6 hours after ingestion of a lipid-rich meal in 30 healthy young men with fasting triglycerides <150 mg/dl and normal fasting glucose levels. Subjects were classified as either normal responders (NR) (postprandial triglyceride maxima < 260 mg/dl) or high responders (HR) (postprandial triglyceride maxima > 260 mg/dl). Levels of CAM were compared in HR and NR, and correlation with postprandial triglyceride, insulin and glucose response was assessed.</p> <p>Results</p> <p>Fasting sICAM-1 and sVCAM-1 levels were significantly higher in HR as compared to NR (p = 0.046, p = 0.03). For sE-selectin there was such a trend (p = 0.05). There was a strong positive and independent correlation between sICAM-1 and postprandial insulin maxima (r = 0.70, p < 0.001). sVCAM-1 showed significant correlation with postprandial triglycerides (AUC) (r = 0.37, p = 0.047). We found no correlation between sCAMs and fasting insulin or triglyceride concentrations.</p> <p>Conclusion</p> <p>This independent association of postprandial triglycerides with sICAM-1 may indicate a particular impact of postprandial lipid metabolism on endothelial reaction.</p

Potreba za psihosocijalnom rehabilitacijom oboljelih od raka

In addition to the healing and alleviation of primary somatic cancer symptoms, the comprehensive psycho oncological treatment of cancer patients is an important and fundamental component of oncological rehabilitation in Germany. Rehabilitation treatment encompasses medical, physiotherapeutic, psychological, and creative therapeutic methods, as well as psycho-educational interventions within the framework of an individualized therapy plan. Psycho-oncological interventions within rehabilitation are governed less by individual therapeutic schools of thought, and more by a supportive, patient-centered approach that integrates various psychotherapeutic methods. Adapted methods and techniques from various psychotherapeutic approaches (behavioral therapy, psychoanalytical psychotherapies, systemic family therapy, or hypnotherapy) are currently used in the treatment of cancer patients. A total of N=116 patients of the Paracelsus Clinic am See in Bad Gandersheim were able to be included in the study. In summary, this study shows that about two thirds of the patients admitted to the oncological rehabilitation clinic exhibit middle to high degrees of distress in the areas of anxiety and/or depression. Moreover, it appears to be particularly important to assess not only the mental distress of cancer patients but also their degree of information with regard to psycho-oncological treatment when performing screening for psycho-oncological treatment outside of the rehabilitation clinic setting. Here it is particularly important to accommodate for a differing need for differing forms of treatment (need for counseling, care, or treatment).Sveobuhvatno psiho-onkološko liječenje bolesnika s rakom važan je prilog u liječenju i ublažavanju primarnih somatskih simptoma te temeljna komponenta onkološke rehabilitacije u Saveznoj Republici Njemačkoj. Ova vrsta rehabilitacije obuhvaća medicinske, fizioterapijske, psihološke te kreativno terapijske pristupe, ali i psihoedukacijske intervencije u okviru individualiziranih terapijskih programa. Psiho-onkološki rehabilitacijski postupci manje su određeni kognitivnim psihoterapijskim metodma, a više potpornim, pacijentu usmjerenim pristupima koji obuhvaćaju različite psihoterapijske tehnike. Prilagođene metode i tehnike iz različitih psihoterapijskih pristupa (bihevioralna terapija, psihoanalitička psihoterapija, sistemska obiteljska terapija ili hipnoterapija) predstavljaju suvremeni koncept u liječenju onkoloških bolesnika. Ova studija provedena je na uzorku od 116 pacijenata Paracelsus Clinic am See u Bad Gandersheimu. Rezultati studije pokazali su da dvije trećine pacijenata uključenih u onkološku rehabilitaciju pokazuje srednji do visok stupanj poremećaja u području anksioznosti i/ili depresije. Osim toga, osobito je važno da se u uvjetima definiranja psiho-onkološkog liječenja u izvankliničkim uvjetima ne procjenjuje samo vrsta i stupanj psihičkog poremećaja, već također i razina informiranosti o psiho-onkološkom liječenju. U tom smislu posebno je važno različite oblike liječenja prilagoditi različitim osobnim potrebamabolesnika (npr. potreba za savjetovanjem, njegom, liječenjem)