148 research outputs found
Optimal transport of ultracold atoms in the non-adiabatic regime
We report the transport of ultracold atoms with optical tweezers in the
non-adiabatic regime, i.e. on a time scale on the order of the oscillation
period. We have found a set of discrete transport durations for which the
transport is not accompanied by any excitation of the centre of mass of the
cloud. We show that the residual amplitude of oscillation of the dipole mode is
given by the Fourier transform of the velocity profile imposed to the trap for
the transport. This formalism leads to a simple interpretation of our data and
simple methods for optimizing trapped particles displacement in the
non-adiabatic regime
Role of Austenitization Temperature on Structure Homogeneity and Transformation Kinetics in Austempered Ductile Iron
This paper considers the important factors of the production of high-strength ADI (Austempered Ductile Iron); namely, the austenitization stage during heat treatment. The two series of ADI with different initial microstructures were taken into consideration in this work. Experiments were carried out for castings with a 25-mm-walled thickness. Variable techniques (OM, SEM, dilatometry, DSC, Variable Magnetic Field, hardness, and impact strength measurements) were used for investigations of the influence of austenitization time on austempering transformation kinetics and structure in austempered ductile iron. The outcome of this work indicates that the austenitizing temperature has a very significant impact on structure homogeneity and the resultant mechanical properties. It has been shown that the homogeneity of the metallic matrix of the ADI microstructure strongly depends on the austenitizing temperature and the initial microstructure of the spheroidal cast irons (mainly through the number of graphite nodules). In addition, this work shows the role of the austenitization temperature on the formation of Mg–Cu precipitations in ADI
Immunogenicity of unprocessed and photooxidized bovine and human osteochondral grafts in collagen-sensitive mice
BACKGROUND: Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased cartilage. There are drawbacks to both of these methods, however. Another possible source for osteochondral grafting is photooxidized xenograft scaffolds. The purpose of this study was to evaluate the adaptive immune response to unprocessed and photooxidized xenogeneic osteochondral grafts in a collagen-sensitive mouse model. METHODS: Unprocessed and photooxidized bovine and human osteochondral grafts were used. The grafts were implanted subcutaneously in collagen-sensitive DBA/1LacJ mice for four or twelve weeks. ELISPOT assays were conducted with spleen cells to evaluate the number of collagen-specific T cells that produce IL-2, IL-4, IL-5 or IFN-γ. Serum was collected and ELISA assays were performed to determine the titers of collagen-specific and total IgG, IgG1, IgG2a, or IgM antibodies. Histology was conducted on the retrieved osteochondral grafts. RESULTS: Results indicated that, with respect to adaptive T cell immunity, the photooxidized bovine grafts, unprocessed human grafts and photooxidized human grafts did not induce a significant response to collagen. The unprocessed bovine grafts, however, were slightly more immunogenic, inducing a weak immune response. With respect to antibody production, the bovine grafts were less immunogenic than the human grafts. Bovine collagen-specific IgG antibodies were not induced by these grafts, but production of IgM after twelve weeks was observed with both the unprocessed and photooxidized bovine grafts. In contrast, photooxidized human osteochondral grafts induced IgG1 and IgG2a antibodies, while the unprocessed human grafts did not. Pre-existing human collagen-specific IgM antibodies were present in all mice, including sham-operated negative controls that did not receive an implant. Histological analysis revealed some degree of fibrous encapsulation and inflammatory infiltrations in both bovine and human implants, whether unprocessed or photooxidized. CONCLUSION: Both bovine and human cartilage grafts showed weak, but clear immunogenicity in the DBA/1LacJ mice, indicating that immunogenic collagen was still contained in the grafts, even after cleaning and photooxidation. The process of photooxidation is still important in osteochondral grafting, since it stabilizes the surface of the cartilage by cross-linking the collagen fibers, and allows for immediate load bearing and joint resurfacing
Tn1546 is part of a larger plasmid-encoded genetic unit horizontally disseminated among clonal Enterococcus faecium lineages
o determine the genetic composition of the first VanA-type plasmid (pIP816) reported, which was isolated from a clinical Enterococcus faecium (BM4147) strain in France in 1986, and to reveal the genetic units responsible for the dissemination of the vanA gene cluster by comparisons with current, published and additionally generated vanA-spanning plasmid sequences obtained from a heterogeneous E. faecium strain collection (n = 28).Plasmid sequences were produced by shotgun sequencing using ABI dye chemistry and primer walking, and were subsequently annotated. Comparative sequence analysis of the vanA region was done with published plasmids, with a partial vanA plasmid (pVEF4) reported here and to >140 kb of sequence obtained from a collection of vanA-harbouring plasmid fragments. Bioinformatic analyses revealed that pIP816 from 1986 and contemporary vanA plasmids shared a conserved genetic fragment of 25 kb, spanning the 10.85 kb vanA cluster encoded by Tn1546, and that the larger unit is present in both clinical and animal complexes of E. faecium. A new group II intron in pVEF4 was characterized. Comparative DNA analyses suggest that Tn1546 disseminates in and between clonal complexes of E. faecium as part of a larger genetic unit, possibly as a composite transposon flanked by IS1216 elements
Neuroprotective Potential of Biphalin, Multireceptor Opioid Peptide, Against Excitotoxic Injury in Hippocampal Organotypic Culture
Biphalin is a dimeric opioid peptide that exhibits affinity for three types of opioid receptors (MOP, DOP and KOP). Biphalin is undergoing intensive preclinical study. It was recognized that activation of δ-opioid receptor elicits neuroprotection against brain hypoxia and ischemia. We compare the effect of biphalin and morphine and the inhibition of opioid receptors by naltrexone on survival of neurons in rat organotypic hippocampal cultures challenged with NMDA. Findings: (1) 0.025–0.1 μM biphalin reduces NMDA-induced neuronal damage; (2) biphalin neuroprotection is abolished by naltrexone; (3) reduced number of dead cells is shown even if biphalin is applied with delay after NMDA challenge
Comparative Analysis of Legislative Requirements About Patients' Access to Biotechnological Drugs for Rare Diseases in Central and Eastern European Countries
Objectives: The aim of the study was to compare the access of patients with rare diseases (RDs) to biotechnological drugs in several Central and Eastern European countries (CEECs). We focused on the legislative pricing and reimbursement requirements, availability of biotechnological orphan medicinal products (BOMPs) for RDs, and reimbursement expenditures. Methods: A questionnaire-based survey was conducted among experts from 10 CEECs: Bulgaria, Croatia, Estonia, Greece, Hungary, Poland, Romania, Slovakia, Serbia, and Macedonia. The legal requirements for reimbursement and pricing of BOMPs were collected. All BOMPs and medicines without prior orphan designations were extracted from the European list of orphan medicinal products, 2017. The reimbursement status of these medicinal products in 2017 in the public coverage of the included CEECs as well as the share of their costs in relation to the total public pharmaceutical spending for the period from 2014 to 2016 were defined. Results: Our survey revealed that some differences in the legal requirements for pricing and reimbursement of BOMPs amongst the countries included in the study. All European Union countries have developed and implemented pharmacoeconomic guidelines with or without some specific reimbursement requirements for orphan medicinal products. Cost-effectiveness analysis, cost-utility analysis, Markov models, meta-analysis, and discount levels of costs and results were required only in Bulgaria, Poland and Hungary. The number of reimbursed BOMPs and biotechnological medicinal products for RDs without prior orphan designation was the highest in Hungary (17 and 40, respectively). Patient-based reimbursement schemes were available only in Hungary for 11 out of 17 BOMPs. Poland and Greece have the highest pharmaceutical expenditure of reimbursed BOMPs with are similar to 214 million and 180 million EUR, respectively in the observed period from 2014 to 2016. High proportion of the pharmaceutical expenditure on the reimbursed biotechnological medicinal products for RDs for the observed period 2014-2016 is presented in Bulgaria and Slovakia. Conclusions: The non-European Union CEECs face a significant delay in the legal implementation of pharmacoeconomic guideline for assessment of BOMPs. The access to BOMPs is similar among the observed CEECs and the countries with the best access are Hungary and Greece. The influence of BOMP expenditures on the budget in the individual countries is significant
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