Publications by authors named "Kirill Voronin"

13 Publications

  • Page 1 of 1

Optical Constants and Structural Properties of Epitaxial MoS Monolayers.

Nanomaterials (Basel) 2021 May 27;11(6). Epub 2021 May 27.

Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, 9 Institutsky Lane, 141700 Dolgoprudny, Russia.

Two-dimensional layers of transition-metal dichalcogenides (TMDs) have been widely studied owing to their exciting potential for applications in advanced electronic and optoelectronic devices. Typically, monolayers of TMDs are produced either by mechanical exfoliation or chemical vapor deposition (CVD). While the former produces high-quality flakes with a size limited to a few micrometers, the latter gives large-area layers but with a nonuniform surface resulting from multiple defects and randomly oriented domains. The use of epitaxy growth can produce continuous, crystalline and uniform films with fewer defects. Here, we present a comprehensive study of the optical and structural properties of a single layer of MoS synthesized by molecular beam epitaxy (MBE) on a sapphire substrate. For optical characterization, we performed spectroscopic ellipsometry over a broad spectral range (from 250 to 1700 nm) under variable incident angles. The structural quality was assessed by optical microscopy, atomic force microscopy, scanning electron microscopy, and Raman spectroscopy through which we were able to confirm that our sample contains a single-atomic layer of MoS with a low number of defects. Raman and photoluminescence spectroscopies revealed that MBE-synthesized MoS layers exhibit a two-times higher quantum yield of photoluminescence along with lower photobleaching compared to CVD-grown MoS, thus making it an attractive candidate for photonic applications.
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http://dx.doi.org/10.3390/nano11061411DOI Listing
May 2021

Optical Constants of Chemical Vapor Deposited Graphene for Photonic Applications.

Nanomaterials (Basel) 2021 May 7;11(5). Epub 2021 May 7.

Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, 9 Institutsky Lane, 141700 Dolgoprudny, Russia.

Graphene is a promising building block material for developing novel photonic and optoelectronic devices. Here, we report a comprehensive experimental study of chemical-vapor deposited (CVD) monolayer graphene's optical properties on three different substrates for ultraviolet, visible, and near-infrared spectral ranges (from 240 to 1000 nm). Importantly, our ellipsometric measurements are free from the assumptions of additional nanometer-thick layers of water or other media. This issue is critical for practical applications since otherwise, these additional layers must be included in the design models of various graphene photonic, plasmonic, and optoelectronic devices. We observe a slight difference (not exceeding 5%) in the optical constants of graphene on different substrates. Further, the optical constants reported here are very close to those of graphite, which hints on their applicability to multilayer graphene structures. This work provides reliable data on monolayer graphene's optical properties, which should be useful for modeling and designing photonic devices with graphene.
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http://dx.doi.org/10.3390/nano11051230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8150576PMC
May 2021

Platelet function and bleeding at different phases of childhood immune thrombocytopenia.

Sci Rep 2021 Apr 30;11(1):9401. Epub 2021 Apr 30.

National Medical Research Center of Pediatric Hematology, Oncology and Immunology Named After Dmitry Rogachev, Russian Ministry of Healthcare, 1 Samory Mashela Str, Moscow, Russia, 117997.

Immune thrombocytopenia (ITP) is believed to be associated with platelet function defects. However, their mechanisms are poorly understood, in particular with regard to differences between ITP phases, patient age, and therapy. We investigated platelet function and bleeding in children with either persistent or chronic ITP, with or without romiplostim therapy. The study included 151 children with ITP, of whom 56 had disease duration less than 12 months (grouped together as acute/persistent) and 95 were chronic. Samples of 57 healthy children were used as controls, while 5 patients with leukemia, 5 with aplastic anemia, 4 with MYH9-associated thrombocytopenia, and 7 with Wiskott-Aldrich syndrome were used as non-ITP thrombocytopenia controls. Whole blood flow cytometry revealed that platelets in both acute/persistent and chronic ITP were increased in size compared with healthy donors. They were also pre-activated as assessed by PAC1, CD62p, cytosolic calcium, and procoagulant platelet levels. This pattern was not observed in other childhood thrombocytopenias. Pre-activation by CD62p was higher in the bleeding group in the chronic ITP cohort only. Romiplostim treatment decreased size and pre-activation of the patient platelets, but not calcium. Our data suggest that increased size, pre-activation, and cytosolic calcium are common for all ITP platelets, but their association with bleeding could depend on the disease phase.
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http://dx.doi.org/10.1038/s41598-021-88900-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8087794PMC
April 2021

Nicotinamide (vitamin B3) treatment improves response to G-CSF in severe congenital neutropenia patients.

Br J Haematol 2021 02 20;192(4):788-792. Epub 2021 Jan 20.

Oncology and Immunology Ministry of Healthcare of Russian Federation, Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Moskva, Russia.

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http://dx.doi.org/10.1111/bjh.17313DOI Listing
February 2021

Efficacy of romiplostim in treatment of thrombocytopenia in children with Wiskott-Aldrich syndrome.

Br J Haematol 2021 01 31;192(2):366-374. Epub 2020 Oct 31.

Department of Immunology, Dmitry Rogachev National Medical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia.

Wiskott-Aldrich syndrome (WAS) is a life-threatening primary immunodeficiency associated with bleeding of variable severity due to thrombocytopenia. Correction of the thrombocytopenia is of paramount importance for most WAS patients. We report a retrospective analysis of the safety and efficacy of romiplostim treatment in reducing thrombocytopenia and bleeding tendency in 67 children (median age 1·3 years) with genetically confirmed WAS, followed in eight months (range, 1-12 months). Complete or partial primary responses regarding platelet counts were observed in 22 (33%) and 18 (27%) subjects, respectively. Yet, even in the non-responder group, the risk of haemorrhagic events decreased significantly, to 21%, after the first month of treatment. The responses tended to be durable and stable over time, with no significant fluctuations in platelets counts. The results of this retrospective study of a large cohort of WAS patients demonstrates that romiplostim can be used to increase platelet counts and reduce the risks of life-threatening bleeding in WAS patients awaiting haematopoietic stem cell transplantation or forgoing the procedure for various reasons.
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http://dx.doi.org/10.1111/bjh.17174DOI Listing
January 2021

Primary Immunodeficiencies in Russia: Data From the National Registry.

Front Immunol 2020 6;11:1491. Epub 2020 Aug 6.

Tatarstan Pediatric Republican Clinical Hospital, Kazan, Russia.

Primary immunodeficiencies (PID) are a group of rare genetic disorders with a multitude of clinical symptoms. Characterization of epidemiological and clinical data via national registries has proven to be a valuable tool of studying these diseases. The Russian PID registry was set up in 2017, by the National Association of Experts in PID (NAEPID). It is a secure, internet-based database that includes detailed clinical, laboratory, and therapeutic data on PID patients of all ages. The registry contained information on 2,728 patients (60% males, 40% females), from all Federal Districts of the Russian Federation. 1,851/2,728 (68%) were alive, 1,426/1,851 (77%) were children and 425/1,851 (23%) were adults. PID was diagnosed before the age of 18 in 2,192 patients (88%). Antibody defects (699; 26%) and syndromic PID (591; 22%) were the most common groups of PID. The minimum overall PID prevalence in the Russian population was 1.3:100,000 people; the estimated PID birth rate is 5.7 per 100,000 live births. The number of newly diagnosed patients per year increased dramatically, reaching the maximum of 331 patients in 2018. The overall mortality rate was 9.8%. Genetic testing has been performed in 1,740 patients and genetic defects were identified in 1,344 of them (77.2%). The median diagnostic delay was 2 years; this varied from 4 months to 11 years, depending on the PID category. The shortest time to diagnosis was noted in the combined PIDs-in WAS, DGS, and CGD. The longest delay was observed in AT, NBS, and in the most prevalent adult PID: HAE and CVID. Of the patients, 1,622 had symptomatic treatment information: 843 (52%) received IG treatment, mainly IVIG (96%), and 414 (25%) patients were treated with biological drugs. HSCT has been performed in 342/2,728 (16%) patients, of whom 67% are currently alive, 17% deceased, and 16% lost to follow-up. Three patients underwent gene therapy for WAS; all are currently alive. Here, we describe our first analysis of the epidemiological features of PID in Russia, allowing us to highlight the main challenges around PID diagnosis and treatment.
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http://dx.doi.org/10.3389/fimmu.2020.01491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7424007PMC
May 2021

Platelet function and bleeding in chronic lymphocytic leukemia and mantle cell lymphoma patients on ibrutinib.

J Thromb Haemost 2020 10;18(10):2672-2684

City Clinical Hospital named after S.P. Botkin, Moscow, Russia.

Background: Therapy with irreversible Bruton's tyrosine kinase inhibitor ibrutinib in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) is associated with bleeding.

Objectives: To propose the predictive markers of such bleeding, as well as mechanisms responsible for decreased bleeding at later therapy stages.

Patients/methods: We investigate platelet functional activity in 50 CLL and 16 MCL patients on ibrutinib using flow cytometry and light transmission aggregometry.

Results: Prior to treatment, both patient groups had decreased platelet counts; impaired aggregation with adenosine diphosphate (ADP); and decreased binding of CD62P, PAC1, and annexin V upon stimulation. Bleeding in patients treated with ibrutinib was observed in 28 (56%) CLL patients, who had decreased aggregation with ADP and platelet count before therapy. Their platelet count on therapy did not change, platelet aggregation with ADP steadily improved, and aggregation with collagen first decreased and then increased in anticorrellation with bleeding. Bleeding in MCL was observed in 10 (62%) patients, who had decreased dense granule release before therapy. ADP and ristocetin induced platelet aggregation in ibrutinib-treated MCL patients increased on therapy, while collagen-induced aggregation evolved similarly to CLL patients.

Conclusions: Our results suggest that ibrutinib-dependent bleeding in CLL patients involves three mechanisms: decreased platelet count (the most important discriminator between bleeding and non-bleeding patients), impaired platelet response to ADP caused by CLL, and inhibition by ibrutinib. Initially, ibrutinib shifts the balance to bleeding, but then it is restored because of the improved response to ADP.
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http://dx.doi.org/10.1111/jth.14943DOI Listing
October 2020

Vertically Coupled Plasmonic Racetrack Ring Resonator for Biosensor Applications.

Sensors (Basel) 2019 Dec 30;20(1). Epub 2019 Dec 30.

Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny 141700, Russia.

Plasmonic chemical and biological sensors offer significant advantages such as really compact sizes and extremely high sensitivity. Biosensors based on plasmonic waveguides and resonators are some of the most attractive candidates for mobile and wearable devices. However, high losses in the metal and complicated schemes for practical implementation make it challenging to find the optimal configuration of a compact plasmon biosensor. Here, we propose a novel plasmonic refractive index sensor based on a metal strip waveguide placed under a waveguide-based racetrack ring resonator made of the same metal. This scheme guarantees effective coupling between the waveguide and resonator and low loss light transmittance through the long-range waveguide. The proposed device can be easily fabricated (e.g., using optical lithography) and integrated with materials like graphene oxide for providing adsorption of the biomolecules on the sensitive part of the optical elements. To analyze the properties of the designed sensing system, we performed numerical simulations along with some analytical estimations. There is one other interesting general feature of this sensing scheme that is worth pointing out before looking at its details. The sensitivity of the considered device can be significantly increased by surrounding the resonator with media of slightly different refractive indices, which allows sensitivity to reach a value of more than 1 μm per refractive index unit.
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http://dx.doi.org/10.3390/s20010203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983217PMC
December 2019

Control of graft-versus-host disease with rabbit anti-thymocyte globulin, rituximab, and bortezomib in TCRαβ/CD19-depleted graft transplantation for leukemia in children: a single-center retrospective analysis of two GVHD-prophylaxis regimens.

Pediatr Transplant 2020 02 3;24(1):e13594. Epub 2019 Nov 3.

Department of Hematopoietic Stem Cell Transplantation, Dmitriy Rogachev National Center for Pediatric Hematology, Oncology and Immunology, Moscow, Russia.

Both acute GVHD and chronic GVHD remain the leading cause of morbidity and death after allogeneic HSCT. We conducted a retrospective analysis comparing two GVHD-prophylaxis regimens: 35 patients received "Regimen 1" (horse ATG, tacrolimus, and methotrexate) and 46 "Regimen 2" (rabbit ATG, rituximab, and peritransplant bortezomib). All 81 patients with a median age of 9 (0.6-23) years with ALL (n = 31) or AML (n = 50) in complete remission received TCRαβ/CD19-depleted transplants between May 2012 and October 2016, from 40 HLA-matched unrelated and 41 haploidentical donors. After a median follow-up of 3.9 years, the CI of acute GVHD II-IV was 15% (95% CI: 7-30) in the "Regimen 2" group and 34% (95% CI: -54) in the "Regimen 1" group, P = .05. "Regimen 2" was also more effective in the prevention of chronic GVHD; the CI at 1 year after HSCT was 7% (95% CI: 2-19) vs 31% (95% CI: 19-51), P = .005. The CI of relapse at 3 years adjusted for the GVHD-prophylaxis regimen groups 31% (95% CI: 19-51) for the "Regimen 1" vs 21% (95% CI: 11-37) for the "Regimen 2", P = .3. The retrospective observation suggests that the use of the rATG, rituximab, and bortezomib was associated with significantly lower rate of GVHD without the loss of anti-leukemic activity.
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http://dx.doi.org/10.1111/petr.13594DOI Listing
February 2020

Mismatched related vs matched unrelated donors in TCRαβ/CD19-depleted HSCT for primary immunodeficiencies.

Blood 2019 11;134(20):1755-1763

Department of Hematopoietic Stem Cell Transplantation.

TCRαβ+/CD19+ graft depletion effectively prevents graft-versus-host disease (GVHD). In the current study, we compared the outcomes of hematopoietic stem cell transplantation (HSCT) with TCRαβ+/CD19+ depletion from matched unrelated donors (MUDs) and mismatched related donors (MMRDs) in patients with primary immunodeficiency (PID). A total of 98 pediatric patients with various PIDs underwent HSCT with TCRαβ+/CD19+ graft depletion from MUDs (n = 75) and MMRDs (n = 23). All patients received a fludarabine-/treosulfan-based conditioning regimen, with 73 also receiving a second alkylating agent. For GVHD prophylaxis, all but 2 received serotherapy (antithymocyte globulin) before HSCT and a short course of posttransplant immunosuppression. Neutrophil and platelet engraftment in both the MUD and MMRD groups occurred on days 14 and 13, respectively. The incidence of secondary graft failure was 0.16 and 0.17 (P = .85), respectively. The cumulative incidence of acute GVHD grade 2 to 4 was 0.17 in the MUD group and 0.22 in the MMRD group (P = .7). The incidence of cytomegalovirus (CMV) viremia was 0.5 in the MUD group and 0.6 in the MMRD group (P = .35). The frequency of CMV disease was high (17%), and the most common manifestation was retinitis. The kinetics of immune recovery was similar in both groups. The overall survival was 0.86 in the MUD group and 0.87 in the MMRD group (P = .95). In our experience, there was no difference in the outcomes of HSCT performed from MUD and MMRD. Hence, given the immediate availability of donors, in the absence of HLA-identical siblings, HSCT with TCRαβ+/CD19+ graft depletion from MMRDs can be considered as the first choice in patients with PID.
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http://dx.doi.org/10.1182/blood.2019001757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856988PMC
November 2019

Graphene-Supported Thin Metal Films for Nanophotonics and Optoelectronics.

Nanomaterials (Basel) 2018 Dec 15;8(12). Epub 2018 Dec 15.

Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny 141700, Russia.

Graphene-metal hybrid nanostructures have attracted considerable attention due to their potential applications in nanophotonics and optoelectronics. The output characteristics of devices based on such nanostructures largely depend on the properties of the metals. Here, we study the optical, electrical and structural properties of continuous thin gold and copper films grown by electron beam evaporation on monolayer graphene transferred onto silicon dioxide substrates. We find that the presence of graphene has a significant effect on optical losses and electrical resistance, both for thin gold and copper films. Furthermore, the growth kinetics of gold and copper films vary greatly; in particular, we found here a significant dependence of the properties of thin copper films on the deposition rate, unlike gold films. Our work provides new data on the optical properties of gold and copper, which should be considered in modeling and designing devices with graphene-metal nanolayers.
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http://dx.doi.org/10.3390/nano8121058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316737PMC
December 2018

Risk Factors for and the Clinical Impact of Cytomegalovirus and Epstein-Barr Virus Infections in Pediatric Recipients of TCR-α/β- and CD19-Depleted Grafts.

Biol Blood Marrow Transplant 2017 Mar 27;23(3):483-490. Epub 2016 Dec 27.

Department of Hematopoietic Stem Cell Transplantation, Dmitriy Rogachev Federal Center for Pediatric Hematology, Oncology and Immunology, Moscow, Russia. Electronic address:

Alpha/beta T cell and CD19 depletion are used to improve the outcomes of hematopoietic stem cell transplantation (HSCT). We evaluated the burden of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in pediatric patients after this HSCT type. A cohort of 182 patients with malignant (n = 114) or nonmalignant (n = 68) disorders was transplanted from either matched unrelated (n = 124) or haploidentical (n = 58) donors. The cumulative incidence of CMV and EBV viremia were 51% and 33%, respectively. Acute graft-versus-host disease (GVHD) grades II to IV, D-/R+ serology, and malignant HSCT indications were associated with increased risk of CMV viremia. CMV disease developed in 10 patients (6%). The occurrence of CMV viremia was not associated with inferior outcomes. Acute GVHD grade ≥ II was the only factor significantly associated with an increased risk of EBV viremia. Rituximab significantly decreased the rate of EBV reactivation in a subgroup that received a higher B cell dose in the graft. The rate of EBV-associated disease was .5%, and EBV viremia did not affect survival. TCR-α/β and CD19 depletion are associated with a significant rate of CMV viremia that does not affect survival. The hazard of EBV post-transplant lymphoproliferative disease (PTLD) is eliminated by the combination of CD19 depletion and rituximab.
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http://dx.doi.org/10.1016/j.bbmt.2016.12.635DOI Listing
March 2017

Ischemia-induced modifications in hippocampal CA1 stratum radiatum excitatory synapses.

Hippocampus 2006 ;16(10):814-25

Department of Cytology, Bogomoletz Institute of Physiology, Kiev, Ukraine.

Relatively mild ischemic episode can initiate a chain of events resulting in delayed cell death and significant lesions in the affected brain regions. We studied early synaptic modifications after brief ischemia modeled in rats by transient vessels' occlusion in vivo or oxygen-glucose deprivation in vitro and resulting in delayed death of hippocampal CA1 pyramidal cells. Electron microscopic analysis of excitatory spine synapses in CA1 stratum radiatum revealed a rapid increase of the postsynaptic density (PSD) thickness and length, as well as formation of concave synapses with perforated PSD during the first 24 h after ischemic episode, followed at the long term by degeneration of 80% of synaptic contacts. In presynaptic terminals, ischemia induced a depletion of synaptic vesicles and changes in their spatial arrangement: they became more distant from active zones and had larger intervesicle spacing compared to controls. These rapid structural synaptic changes could be implicated in the mechanisms of cell death or adaptive plasticity. Comparison of the in vivo and in vitro model systems used in the study demonstrated a general similarity of these early morphological changes, confirming the validity of the in vitro model for studying synaptic structural plasticity.
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http://dx.doi.org/10.1002/hipo.20211DOI Listing
December 2006