Optimization of Pre-Heat Treatment for Nitriding

To achieve a core strength that meets the requirements during service life, components to be nitrided are subjected to a pre-heat treatment. Since a higher strength prior to nitriding also has a positive effect on the achievable strength in the nitrided layer, an optimization of the pre-heat treatment may lead to better service characteristics of nitrided components. For this purpose, different optimizations of pre-heat treatment were investigated on the nitriding and quenching and tempering steels EN31CrMoV9 and EN42CrMo4 (AISI4140). One strategy was a change of the austenitization temperature for EN31CrMoV9 from 870 °C to 950 °C in order to solve the coarse carbides of the as-delivered state and realize a finer distribution of the carbides in the quenched and tempered structure. This special treatment lead to a higher hardness compared to the conventional treatment. The second investigated pre-heat treatment variant was a bainitic treatment instead of quenching and tempering. The bainitic initial microstructure increased the diffusion depth compared to conventionally quenched and tempered specimens. In addition the maximum hardness of the nitrided layer, the core hardness was significantly higher on the specimens with the bainitic microstructure. During subsequent nitriding, however, the bainite is tempered and loses some of its hardness.

Reduced Neutralization of SARS-CoV-2 Omicron Variant by Vaccine Sera and monoclonal antibodies

Due to numerous mutations in the spike protein, the SARS-CoV-2 variant of concern Omicron (B.1.1.529) raises serious concerns since it may significantly limit the antibody-mediated neutralization and increase the risk of reinfections. While a rapid increase in the number of cases is being reported worldwide, until now there has been uncertainty about the efficacy of vaccinations and monoclonal antibodies. Our in vitro findings using authentic SARS-CoV-2 variants indicate that in contrast to the currently circulating Delta variant, the neutralization efficacy of vaccine-elicited sera against Omicron was severely reduced highlighting T-cell mediated immunity as essential barrier to prevent severe COVID-19. Since SARS-CoV-2 Omicron was resistant to casirivimab and imdevimab, genotyping of SARS-CoV-2 may be needed before initiating mAb treatment. Variant-specific vaccines and mAb agents may be required to treat COVID-19 due to Omicron and other emerging variants of concern.

Stent Deployment as an Emergency Alternative Treatment for Acute Stroke. Case Series

Introduction. Acute ischemic stroke due to large vessel occlusion refractory to aspiration or mechanical thrombectomy is a therapeuticchallenge. Objective. A treatment variant is in order. Methods. In the last three years, we admitted seven patients with refractory largevessel occlusions, for all of whose aspiration and mechanical thrombectomy had failed. A Solitaire AB stent was deployed as a rescuemeasure. Results. Data was retrospectively analyzed. Six out of seven patients had a good clinical outcome as measured by mTICIand mRS twelve months after the procedure. One patient died after the first follow-up visit, one month after endovascular therapy.Conclusion. Results of this small series support the role of stent deployment as a rescue measure for such challenging patients.

Molecular circulating tumor DNA response to identify long-term survival in patients receiving immunotherapy with initial radiologic stable disease.

2546 Background: Early on-treatment changes in ctDNA may identify responders to immunotherapy and complement radiologic assessment of benefit. Here we investigate how early changes in ctDNA associate with long-term survival following treatment with immunotherapy, and if differential patterns in molecular ctDNA response (MCR) among patients with radiologic stable disease (SD) at first on-treatment scan could identify patients deriving benefit from treatment. Methods: Paired pre- and on-treatment (week 6-8) plasma samples from 3 cohorts of patients treated with durvalumab (D) +/- tremelimumab (D+T) were evaluated (NCT01693562, NCT02087423, NCT02261220). CtDNA was profiled with the 73-gene Guardant 360 assay. Nonsynonymous variants were summarized per patient to calculate variant allelic frequency changes (dVAF) and on-treatment variant allele frequency (pVAF). A combination of dVAF and pVAF was used to define MCR. Results: The reduction of ctDNA (dVAF<0) and undetectable on-treatment ctDNA (pVAF=0) were each associated with improved OS and PFS. An optimal threshold for MCR was determined from one cohort, then applied to the other cohorts. MCR associated with significantly improved PFS and OS across all three cohorts (Table). MCR was then applied to a pooled subgroup of patients with initial radiologic SD from all three cohorts (n=78). Patients with radiologic SD and MCR were significantly more likely than those without MCR to achieve radiologic CR or PR (pooled Odds ratio 12.7, p<0.001), had improved PFS (stratified pooled HR 0.36, p<0.001), and improved OS (stratified pooled HR 0.38, p=0.005). Conclusions: MCR is an early on-treatment tool that may identify patients with improved long-term survival and patients with radiologic SD who derive clinical benefit from immunotherapy. MCR may be a supportive endpoint in prospective clinical trials. MCR and survival benefit. [Table: see text]

The Study Toughness Ecologicals Metals Materials

This aim of this is to determine the manner of realizing tubing pipe, which have to comply with suplimentary requirements concerning the notch impact strength at lower temperature (below - 300C). We realized �73 x 5.51 mm and �89 x 13 mm pipes applying various final heat treatment variants. For each heat treatment variant were determined the mechanical properties and the impact absorbed energy at temperatures between (-60 0C and +15 0C).

THE POSSIBILITIES OF STRENGTHENING OF THE SURFACE LAYER OF NODULAR IRON BY LASER ALLOYING WITH SILICON NITRIDE ON THE EXAMPLE OF A ROCKER ARM

In the order to increase the resistance to the friction wear of machine parts appropriate surface treatment application is needed. The aim of presented research was to evaluate the laser alloying with silicon nitride effects obtained in the surface layer of nodular iron and to select the laser treatment parameters that should be appropriate for the treatment of the one of the engine parts, which is a rocker arm. After implementation of silicon nitride into the nodular iron surface layer using laser heating, a uniform, fine, dendritic microstructure similar to the hardened white cast of the allayed zone was created in all performed variants. This microstructure resulted in at least 4-times higher hardness in comparison to the core material. The hardness and the alloyed zone dimensions were dependent on the laser heat treatment variant. The laser beam power density of 41 W/mm2 and its velocity of 2.8 mm/s were selected for the treatment of the rocker arm. It was caused by the effects obtained in the surface layer. With these parameters, it was possible to achieve the hardness of 1300 HV0.1 and the width of the alloying zone of over 4 mm, which is enough to strengthen the surface area of the rocker arm most exposed to the tribological wear.

Operative laparoscopy in neoplasm and benign tumors of ovaries in teenagers

The importance of such current diagnosis methods as ultrasound examinations, computer tomography NMR-tomography for revealing the volumetric tumors of uterine appendages is noted. The most informative diagnosis method is laparoscopy used at present and as an operative treatment variant. The peculiarities of laparoscopic operations call for exacting indications.