Publications by authors named "A V Nokhrin"

7 Publications

Study of the Hydrolytic Stability of Fine-Grained Ceramics Based on YNdAlO Oxide with a Garnet Structure under Hydrothermal Conditions.

Materials (Basel) 2021 Apr 23;14(9). Epub 2021 Apr 23.

Materials Science Department, Physico-Technical Research Institure, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia.

The hydrolytic stability of ceramics based on YNdAlO oxide with a garnet structure obtained by the spark plasma sintering (SPS) method has been studied. The tests were carried out in distilled water under hydrothermal conditions in an autoclave and, for comparison, in a static mode at room temperature. The mechanism of leaching of Y and Nd from the ceramics was investigated. It has been shown that at "low" temperatures (25 and 100 °C), the destruction of pores occured, and the intensity of the leaching process was limited by the diffusion of ions from the inner part of the sample to the surface. At "high" test temperatures (200 and 300 °C), intense destruction of the ceramic grain boundaries was observed. It was assumed that the accelerated leaching of neodymium is due to the formation of grain-boundary segregations of Nd in sintered ceramics.
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http://dx.doi.org/10.3390/ma14092152DOI Listing
April 2021

[Surgical treatment of a patient with traumatic rupture of the aortic arch and late oesophageal perforation].

Angiol Sosud Khir 2020 ;26(2):175-182

Department of Vascular Surgery, Municipal Multimodality Hospital #2, Saint Petersburg, Russia.

Described herein is a clinical case report regarding a patient presenting with traumatic rupture of the aortic isthmus with the development of a pseudoaneurysm occupying virtually the entire posterior mediastinum and measuring 20?10 cm in size. He was immediately treated as an emergency to undergo prosthetic reconstruction of the portion of the aortic arch and descending thoracic aorta by means of temporary bypass grafting with a synthetic graft in order to protect the visceral organs. The postoperative period was complicated by oesophageal perforation with the formation of an oesophago-paraprosthetic fistula, infection of the vascular graft, accompanied by the development of pleural empyema and mediastinitis. A second operative procedure was performed, consisting of subclavian-iliac bypass grafting on the right with a polytetrafluoroethylene graft measuring 20 mm in diameter, exclusion of the intrathoracic portion of the oesophagus, creation of a gastro- and oesophagostoma, retrieval of the vascular graft followed by suturing of the aorta, pleurectomy, decortication of the lung, and removal of the empyemic sac on the left. There was no evidence of ischaemia of the spinal cord or visceral arteries. One month postoperatively, he underwent a traumatological stage and 4 months thereafter plasty of the oesophagus with an isoperistaltic gastric pedicle, extirpation of the thoracic portion of the oesophagus, to be later on followed by closure of the oesophagostoma. The patient experienced no difficulties either while walking or during other physical activities, with the ankle-brachial index amounting to 0.9. With time, he developed difficult-to-correct pulmonary hypertension. Unfortunately, the patient eventually died of acute cardiopulmonary insufficiency 9 years after right-sided extra-anatomical subclavian-iliac bypass grafting.
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http://dx.doi.org/10.33529/ANGIO2020219DOI Listing
September 2020

Two-stage approach for surgical treatment of tetralogy of Fallot in underweight children: Clinical and morphological outcomes.

J Card Surg 2019 May 29;34(5):293-299. Epub 2019 Mar 29.

Division of Experimental and Clinical Cardiology, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation.

Background: Two-stage surgery including right ventricular outflow tract (RVOT) stenting with subsequent total surgical repair (TSG) has been suggested as a promising curative option in infants with tetralogy of Fallot (ToF) having comorbidities such as low body weight. However, data on clinical outcomes of such approach and tissue response to RVOT stenting in underweight infants are scarce.

Methods: We recruited 16 underweight (<3 kg; average weight, 2.2 ± 0.4 and 4.7 ± 0.9 kg at the time of RVOT stenting and TSG, respectively) infants (1-3 months of age, average 28.2 ± 4.3 and 100.2 ± 22.3 days at the time of RVOT stenting and TSG, respectively) with ToF and performed RVOT stenting with the subsequent TSG. Excised stents were embedded into epoxy resin and stained by toluidine blue and basic fuchsin.

Results: Fifteen infants had a favorable clinical outcome, probably due to the rapid increase in the body weight, blood oxygen saturation, and left ventricular end-diastolic volume to body surface area ratio indicative of improved pulmonary perfusion. Histological analysis revealed an endothelial cell monolayer at the stent surface with notable neovascularization of stented tissues, which could potentially explain the abovementioned clinical and echocardiography improvements. The only death occurred immediately after RVOT stenting and was caused by a massive subdural hematoma, possibly provoked by grade 2 intraventricular hemorrhage 12 days before the stenting.

Conclusions: We confirm RVOT stenting with the subsequent TSG as a safe and efficient surgical approach for the treatment of underweight children with ToF.
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http://dx.doi.org/10.1111/jocs.14031DOI Listing
May 2019

Study of Structure and Mechanical Properties of Fine-Grained Aluminum Alloys Al-0.6wt.%Mg-Zr-Sc with Ratio Zr:Sc = 1.5 Obtained by Cold Drawing.

Materials (Basel) 2019 Jan 21;12(2). Epub 2019 Jan 21.

Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod 603950, Russia.

The thermal stability of a fine-grained (FG) aluminum wire has been studied in Al-0.6Mg-Zr-Sc alloys with various scandium and zirconium contents. Specimens were obtained by induction casting followed by cold deformation. The FG alloys have been demonstrated to have high thermal stability of the structure and properties due to the annealing pretreatment (320 °C, 2 h, before drawing), which results in deposition of Al₃(ScZr) intermetallic particles. It has been determined that following a prolonged annealing treatment (400 °C, 100 h), the alloys retain a uniform fine-grained structure with an average grain size of 2.4⁻2.8 μm whereas their microhardness measures 405⁻440 MPa.
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http://dx.doi.org/10.3390/ma12020316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356729PMC
January 2019

Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

Micron 2016 Jun 26;85:1-7. Epub 2016 Mar 26.

Division of Experimental and Clinical Cardiology, Research Institute for Complex Issues of Cardiovascular Diseases, Sosnovy Boulevard 6, 650002 Kemerovo, Russian Federation. Electronic address:

A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft.
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http://dx.doi.org/10.1016/j.micron.2016.03.005DOI Listing
June 2016