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Study question Can non-invasive preimplantation genetic testing of aneuploidies (niPGT-A) improve the clinical outcome in IVF patients after proper validation? Summary answer We demonstrate the usefulness of the embryonic cell-free DNA (cfDNA) in the blastocyst culture medium to select more objectively the blastocysts with higher implantation potential. What is known already One of the greatest challenges in IVF is accurately selecting viable embryos that are more likely to achieve healthy livebirths following embryo transfer. Trophectoderm (TE) biopsy and PGT-A provide a direct assessment of chromosome status and improve implantation and clinical pregnancy rates per transfer. A non-invasive alternative is to analyse embryonic cfDNA in the blastocyst culture medium. Previous studies have shown that cfDNA testing in culture medium of blastocysts on day 6 of development allows aneuploidy detection with high concordance rates compared to TE biopsy and inner cell mass (Rubio et al., 2020). Study design, size, duration Observational study of the clinical application of niPGT-A (July 2020-December 2020). The clinical application consisted in a first validation phase, comparing TE biopsies with cfDNA in the media of 28 blastocysts. And, in a second phase, niPGT-A was applied and the outcome of 13 single embryo transfers (SETs) compared to 13 PGT-A SETs and 130 IVF/ICSI SETs performed in a period of six months. In the three groups, women and donors age was ≤38 years. Participants/materials, setting, methods Embryos were cultured in a Geri incubator (Merck) up to day 4, and then individually cultured in 10µl drops of CCSS (Fujifilm) until day 6 in a bench-top K-system. At day 6, blastocysts were vitrified, and media collected in sterile PCR tubes after at least 40 hours in culture. After collection, media were immediately frozen and analyzed by NGS analysis in our reference laboratory (Igenomix, Spain). Deferred transfer was performed according to media results. Main results and the role of chance Before the first clinical cases, a validation of the protocol comparing the results of cfDNA with the TE biopsies of the same day–6 blastocyst was performed, and ploidy concordance rates were 87.5%. Similar results were found for niPGT-A and PGT-A in terms of aneuploidy results and in clinical outcomes. The percentages of informative results were 95% and 97% and the aneuploidy rates were 44% and 46%, for niPGT-A and PGT-A, respectively. Clinical pregnancy rates were in both groups of aneuploidy testing, 69.2%, with 8 ongoing pregnancies (61.5%) and 4 tested by prenatal screaning NACE. For untested embryos clinical pregnancy (57.7%) and ongoing pregnancy rates (48.5%) were lower than in the two groups of tested embryos (niPGT-A and PGT-A). In the niPGT-A cycles embryo transfer was performed according to media results and morphology. We did a secondary analysis of which blastocyst we would transfer, if only morphology is considered. We observed that if we only select the embryos by morphology, in 61.5% of the cases we would choose the same embryo than with niPGT-A, and in 30.4% of the cases we would transfer a blastocyst with an aneuploid medium. Limitations, reasons for caution Our results are encouraging but should be interpreted with caution due to the small sample size. Larger and randomized controlled trials are needed to verify and extend our findings in each group. Wider implications of the findings: We observed consistent results for niPGT-A compared to TE biopsies in our internal validation. These results endorse the clinical application of niPGT-A in the routine of the laboratory and can avoid the embryo manipulation also reducing the subjectivity when embryos are selected only by morphology. Trial registration number Sa–16552/19-EC:428

The numerical simulation of system dynamics is today a standard in the design of railway vehicles; their typical applications are the suspension kinematics, handling performance and ride comfort as well as the generation of load data for lifetime prediction. One of the key points in this type of simulation is the model of the wheel/rail interaction, in other words the definition of the forces exchanged between the wheels and the rail in the contact points. The direction and the magnitude of the contact forces depend on the number and the location of the contact points. The procedure that allows one to define the geometry of the contact then has a significant effect on the reliability of the simulation. The component of the normal contact force to the contact surfaces can be defined as a function of the relative indentation between the surfaces. The component of the contact force tangent to the contact surfaces depends on the relative speeds between the surfaces in the contact area (wheel sliding). The authors have been working on the definition of efficient and reliable models of the interactions between the wheels and the rails and in particular for the definition of the contact points. Different algorithms have been analyzed and compared, based on semi analytical approaches and on neural networks. The paper will summarize the proposed methods and the results obtained from the simulation of two different sceneries. Two different models have been used in this test: the first one was realized with a commercial software, while the second one was developed and implemented by the authors. There is a global agreement between the models, although some differences can be seen during the transients due to the different methods for the determination of the contact points for the integration.

We investigated the pharmacokinetics of meropenem after the first and tenth i.m. administration in patients with respiratory tract infections. Ten patients (mean age 63.8 +/- 5.2 years) received meropenem 500 mg tds for at least ten doses, and plasma and urine antibiotic concentrations were determined by microbiological assay. After the first injection a mean peak plasma concentration of 7.93 +/- 1.29 mg/L was observed at 1 h. Trough levels at 8 h (0.29 +/- 0.16 mg/L) were detectable in five of ten treated patients. The mean terminal half-life was 1.08 +/- 0.2 h with an area under the curve (AUC) value of 23.8 +/- 4.59 mg/L.h, and a cumulative urinary recovery at 8 h of 48.43 +/- 3.12%. There was no evidence of change in the pharmacokinetics of meropenem after repeated i.m. administration, though the mean peak plasma concentration and AUC value were slightly increased. The accumulation ratio (assessed using AUC values) was 1.18 +/- 0.19 after multiple doses and was considered to be of little kinetic and clinical importance. Moreover, many of the trough concentrations of meropenem were below the limit of detection of the assay. After i.m. administration meropenem concentrations exceeded 0.5 mg/L for longer than previously described following i.v. infusion. No adverse events were reported.

The occurrence of Mycobacterium xenopi (MX) isolates is not homogeneous in various geographic zones. In the Florence area, between 1975-1989, strains of MX from 64 different patients have been isolated. The review of bacteriological and clinical data of 46 of them, from whose sputum MX had been grown, allowed to diagnose for 26% the commensal nature of this finding, for 41% the concomitance with a tubercular infection and for the remaining 33% the pathogenicity of this microorganism. The increased occurrence of MX isolates, their high rate of pathogenicity and the remarkable homogeneity of their biochemical, cultural and antimicrobial sensitivity patterns seem to suggest the hypothesis of an endemic focus of this species in the Florence area.