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Space Acoustics participated in a European Space Agency technology application study, performed by LK Engineering (Brno), NETME (Brno) & Thales Space (Cannes), with the objectives of designing, manufacturing & qualifying lightweight tertiary structures for spacecraft. The potential of additive manufacturing to achieve significant advantages over conventionally manufactured parts provides a clear motivation to apply them for space, however their repeatability and quality has to be proven by stringent process and materials control, with many factors to be considered. This study focused mainly on design optimisation, process qualification, and functional strength/stiffness and vibration tests representative of space. Validation of manufacturing processes including raw materials, heat-treatment, post-machining, cleaning, in-process coupon sampling, X-ray CT inspection and metrology. Qualification testing using high level sine and random tests were used to validate the design methodologies and prove the durability of the manufactured parts. The structural requirements of the antenna bracket were optimally achieved using a hybrid design, combining a lightweight lattice type structure with reinforcing embedded frame. The successful design of lightweight lattice type structures using topology optimisation supported by FEM analysis and with corrections based on observed manufacturing details was proven by strength and stiffness tests. The tolerance to structural overloading was checked by increasing the applied vibration loading above the design limits, a gradual degradation was observed, and was closely correlated with predictions. The know-how and experience gained in developing the spacecraft antenna mounting and other parts is being applied in further parts, mainly in Titanium, Aluminium and Inconel materials, in a larger and contemporary ALM manufacturing facility type EOS M400. [ABSTRACT FROM AUTHOR]

In this study, nanoparticle-incorporated nanofiber-covered yarns were prepared using a custom-made needle-free electrospinning system. The ultimate goal of this work was to prepare functional nanofibrous surfaces with antibacterial properties and realize high-speed production. As antibacterial agents, we used various amounts of copper oxide (CuO) and vanadium (V) oxide (V 2 O 5 ) nanoparticles (NPs). Three yarn preparation speeds (100 m/min, 150 m/min, and 200 m/min) were used for the nanofiber-covered yarn. The results indicate a relationship between the yarn speed, quantity of NPs, and antibacterial efficiency of the material. We found a higher yarn speed to be associated with a lower reduction in bacteria. NP-loaded nanofiber yarns were proven to have excellent antibacterial properties against Gram-negative Escherichia coli ( E. coli ). CuO exhibited a greater inhibition and bactericidal effect against E. coli than V 2 O 5 . In brief, the studied samples are good candidates for use in antibacterial textile surface applications, such as wastewater filtration. As greater attention is being drawn to this field, this work provides new insights regarding the antibacterial textile surfaces of nanofiber-covered yarns., Competing Interests: The authors declare no conflict of interest.

The authors present the reasons failed lumbar disc operations among 51 patients, 53% of them were womae and 47% were mae. Age of the patients was from 30 to 73 years (average 49 years). Most of them have had some operations. They complained of constant, strong lumbar pain with sciatic pain, restriction of lumbar spine mobility and paresis. The results were compared after 12 months from final operation with applying 3 methods: decopmpression, transpedicular fixation with decompression and decompession conected with transpedicular fixation and inerbody fusion. Intraoperatively considerable amount of instability (60%) was found. The best results of treatment was gained in decompression conected with transpedicular fixation and interbody fusion. The good result came up 41% in this group and in the other 20%.

Background: Most effects of atrial (ANP) and B-type natriuretic peptide (BNP) result from stimulation of the guanylyl-cyclase type A receptor. Chronic elevation causes hyporesponsiveness to ANP, whereas BNP effects tend to be preserved, implying an additional pathway of action. We, therefore, investigated the hemodynamic effects of co-infusion of ANP, BNP, and, as a positive control acting on type B receptor, C-type natriuretic peptide (CNP). Furthermore, vascular responses to short and prolonged infusions were compared to investigate rapid hyporesponsiveness of guanylyl-cyclase type A receptor., Methods: In 11 healthy volunteers, arterial response to continuous intra-arterial infusion of ANP (60 pmol/100 mL forearm tissue volume [FAV]/min) was assessed by venous occlusion plethysmography. Then, co-infusion of a similar dose of ANP, BNP, or CNP was administered in randomized order. Each infusion phase was followed by a washout period. Then, ANP was restarted, followed by co-infusion of one of the natriuretic peptides not yet infused. After a further washout period, ANP was restarted, followed by co-infusion of the natriuretic peptide not yet co-infused. In 6 subjects, infusion time was adjusted to plasma half-lives (5 times), and in the other 5 subjects, infusion time was 5 minutes., Results: ANP alone caused the expected vasodilation from 2.7 +/- 0.3 mL/min/100 mL FAV to 6.0 +/- 0.9 mL/min/100 mL FAV (P < .004). This response remained unchanged in the group that received short-term infusions (6.2 +/- 0.8 mL/min/100 mL FAV to 6.6 +/- 1.1 mL/min/100mL FAV) but was reduced over time in the group receiving longer-term infusions (6.5 +/- 1.2 mL/min/100 mL FAV to 4.5 +/- 0.7 mL/min/100mL FAV, P < .05; difference between groups P < .05). Co-infusions of ANP, BNP, and CNP caused minor additional vasodilation (mean 0.8 +/- 0.2 mL/min/100ml FAV, P < .01), which did not differ between the different co-infused natriuretic peptides., Conclusion: Our data provide evidence for rapid desensitization of the guanylyl-cyclase type A receptor in humans, but do not support the presence of a BNP-specific receptor.

Background. The aim of this retrospective study was to compare the results of two fixation devices (Ender rods in 118 patients and dynamic hip screw in 98 patients) for treatment of intertrochateric fractures of the hip. Material and methods. The two treatment groups were similar with respect to important preoperative variables such as age, coexisting disseases, bone quality and incidence of stable and unstable fractures. The following outcomes were assessed: quality of reduction, length of hospital stay, early mortality, reoperations, persistent pain at a knee or hip, decrease in range of motion of the knee and leg shortening. Results and conclusions. The subgroup analysis showed higher incidence of complications in patients with unstable type of fracture treated with Ender nailing. These complications included mainly valgus angulation and malrotation of the fracture, need for a secondary procedure due to loss of stabilization and knee pain. Intramedullary stabilization with Ender rods is not recommended in treatment of unstable intertrochanteric fractures of the femur.