ПОЛУЧЕНИЕ ВЫСОКОПРОЧНЫХ ДЕФОРМИРУЕМЫХ АЛЮМИНИЕВЫХ СПЛАВОВ ТИПА АМг10

Traditional grades of aluminum alloys do not always meet the requirements of modern aerospace engineering. Al–Si foundry alloys possess insufficient mechanical strength characteristics and low plasticity due to their structural features (coarse brittle silicon inclusions and intermetallic phases). Therefore they cannot be exposed to pressure treatment. A technique for producing high-strength aluminum alloys, which consists in obtaining ring blanks by means of direct crystallization of melts with application of non-stationary centrifugal force fields and simultaneous introduction of modifiers, is proposed. The microstructure and plasticity of resulting tube-shaped blanks allow them to be exposed to sheeting for subsequent production of pipe workpieces with mechanical strength commensurate with mechanical strength of structural steel. The technique involves hydrothermal synthesis of nanostructured particles of aluminum oxide, which are overheated above the melt temperature prior to introduction into the molten aluminum alloy. This procedure enhances the processes of intercrystalline hardening with minimal fluctuations of internal stresses within the hardened material. The materials have tensile strength of up to 380 MPa (before modification by nanodispersed aluminum oxide it was 210 MPa). The microstructure has showed changes in the acicular dendrite component, which tends to become more dispersed and equiaxial. Eventually this leads to an increase in the mechanical strength by a factor of 1.25–1.32. Традиционные марки алюминиевых сплавов не всегда могут обеспечить выполнение требований современной ракетно-космической и авиационной техники. Литейные сплавы системы Al–Si из-за структурных особенностей – грубых хрупких включений кремния и интерметаллических фаз, имеют невысокий уровень прочностных свойств и низкую пластичность, не позволяющую проводить их обработку давлением. Предложена технология создания высокопрочных алюминиевых сплавов, заключающаяся в получении кольцевых заготовок методом направленной кристаллизации расплава при наложении нестационарных силовых полей центробежных сил и одновременном введении модификаторов. Полученные заготовки имеют микроструктуру и пластичность, позволяющую подвергать их раскатке, и форму трубных заготовок, механическая прочность которых соизмерима с конструкционной сталью. Технология включает в себя гидротермальный синтез наноструктурированных частиц оксида алюминия, которые перед введением в расплав алюминиевого сплава перегреваются выше температуры расплава, что повышает полноту протекания процессов интеркристаллического упрочнения при минимальных колебаниях по объему упрочненного материала внутренних напряжений. Материалы имеют предел прочности до 380 МПа (до модификации нанодисперсным оксидом алюминия – 210 МПа). В микроструктуре наблюдается изменение игольчатой дендритной составляющей, которая становится более дисперсной и равноосной, что и приводит к повышению механической прочности в 1,25–1,32 раза.

Mutations in isocitrate dehydrogenase 1 and 2 occur frequently in intrahepatic cholangiocarcinomas and share hypermethylation targets with glioblastomas

Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in gliomas, myeloid leukemias, chondrosarcomas, and thyroid cancer. We discovered IDH1 and IDH2 mutations in 34 of 326 (10%) intrahepatic cholangiocarcinomas. Tumor with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine (5hmC) and higher 5-methylcytosine (5mC) levels, as well as increased dimethylation of histone H3K79. Mutations in IDH1 or IDH2 were associated with longer overall survival (p = 0.028) and were independently associated with a longer time to tumor recurrence after intrahepatic cholangiocarcinoma resection in multivariate analysis (p = 0.021). IDH1 and IDH2 mutations are significantly associated with increased levels of p53 in intrahepatic cholangiocarcinomas, but no mutations in the p53 gene were found, suggesting that mutations in IDH1 and IDH2 may cause a stress that leads to p53 activation. We identified 2,309 genes that were significantly hypermethylated in 19 cholangiocarcinomas with mutations in IDH1 or IDH2, compared with cholangiocarcinomas without these mutations. Hypermethylated CpG sites were significantly enriched in CpG shores and upstream of transcription start sites, suggesting a global regulation of transcriptional potential. Half of the hypermethylated genes overlapped with DNA hypermethylation in IDH1-mutant gliobastomas, suggesting the existence of a common set of genes whose expression may be affected by mutations in IDH1 or IDH2 in different types of tumors

Transurethral enucleation of large benign prostatic hyperplasia in sodium chloride solution

Background. Transurethral resection is a generally recognized treatment for small to medium-sized benign prostatic hyperplasia (BPH). Numerous original tools are proposed for surgery of large BPH. These include laser (holmium laser enucleation of the prostate) and transurethral (transurethral enucleation with bipolar (TUEB)) enucleation in 0.9 % NaCl solution, which are accompanied by removal of the maximum adenoma tissue volume, short-term recovery, and a substantially fewer early and late complications.Objective: to evaluate the safety and efficiency of TUEB in patients with large BPH.Subjects and methods. TUEB was carried out in 58 patients with large BPH. Their mean age was 64 years. The gland size was ≥ 102 сm3. The residual urine volume in all the patients was more than 100 ml. One year later, the results of treatment were analyzed using the International Prostate Symptom Score (IPSS), Quality of Life (QoL) Questionnaire, as well as from residual urine volume and remaining prostate tissue.Results. The mean time of surgery and enucleation was 90 and 55 min, respectively. The mean volume of removed adenoma tissue was 99 ml. By the end of month 2 following TUEB, there was a progressive reduction in the total IPSS and QoL scores from 35 to 7 and from 5 to 1, respectively, which preserved this trend by the end of a 1-year follow-up. study. The residual urine amount was less than 30 ml. The mean volume of the prostate tissue left was 8.5 сm3 and less than 11.0 сm3. The ultrasound anatomy of the prostatic urethra (transformation of thin-walled spherical TUR defect that is characteristic slit-like one resembles the inverted letter Y) eventually formed by the end of the 1-year follow-up. Stricture of the urethra and contracture of the bladder neck were noted in none of the cases. Conclusion. TUEB is an alternative to open surgery in patients with the enlarged prostate. The use of isotonic NaCl solution as washing fluid allows one to plan longer surgical intervention without fearing water intoxication

Analyzing the effectiveness of dynamic network slicing procedure in 5g network by queuing and simulation models

In this paper, we propose three metrics that could be used for accessing the effectiveness of a dynamic Network Slicing. On the one hand re-slicing could result in more adaptive resource allocation for different virtual network operators (VNO), but could arise the signaling overhead. On the other hand an insufficient amount of re-slicing could significantly decrease the quality of service for VNO users, but reduce the signaling delays. Proposed metrics could be used for analyzing the abovementioned effect. We illustrate the metrics by the simulation model for a simple dynamic network slicing algorithm. We also propose a queuing system approach for analyzing dynamic network slicing for 2 VNOs. © Springer Nature Switzerland AG 2020