Hybrid heterostructures with superconducting/antiferromagnetic interfaces

We report on structural, DC, X-ray and neutron studies of hybrid superconducting mesa-heterostructures with a cuprate antiferromagnetic interlayer Ca1-xSrxCuO2 (CSCO). The upper electrode was bilayer Nb/Au superconductor and copper oxide superconductor YBa2Cu3O7 (YBCO) was the bottom electrode. It was experimentally shown that during the epitaxial growth of the two films YBCO and CSCO a charge carrier doping takes place in the CSCO interlayer with a depth about 20 nm. The conductivity of the doped part of CSCO layer is close to the metal type, while the reference CSCO film, deposited directly on NdGaO3 substrate, behaves as Mott insulator with the hopping conductivity. The interface Au/CSCO is clearly seen on bright-field image of the cross-section of heterostructure and gives the main contribution to the total resistance of mesa-heterostructure.Comment: 16 pages, 9 figure

Nephelometric Method for Determination of Growth Parameters of Chlorella Culture

Nephelometric method for the determination of growth parameters of chlorella culture using a photoelectric colorimeter was described. Use of photoelectric colorimeter for cell counting in suspension requires periodic calibration of meter readings using chlorella standard culture (with a certain cell concentration). Chlorella vulgaris IPPAS С-66, IPPAS С-111 and IPPAS С-2019 strains served as object of research. Density of initial in vitro suspensions (after inoculation) was 0.9 mln cells/ml. Cultivation was carried out during 12 days on a Hoagland medium with a pH of 7 (temperature of 35∘C, illumination of 10 klx). Sample selection for analysis and measurement was carried out daily, three times per day. Based on the obtained data, readings of photoelectric colorimeter KFK-3.01 were calibrated via direct count of chlorella cells quantity in Goryaev’s chamber. Use of calibration curve made it possible to reduce significantly time and error in determination of cell number in suspension cultures. The proposed technique allows counting chlorella cells in the growth and development dynamics with sufficient accuracy, high sensitivity, reproducibility and speed. It can be used for comparative determination of the growth parameters of strains in vitro, standardization of suspension cultures, semi-quantitative determination of chlorella biomass in order to predict the yield of desired product

Новая мутация в гене TYMP: клинико-морфологическая характеристика пациента с синдромом MNGIE

Mitochondrial neurogastrointestinal encephalomyopathy is an extremely rare (1–9:1 000 000, Orphanet, 2021) multisystem genetic disease caused by mutations in the TYMP gene encoding the enzyme thymidine phosphorylase.The article presents the data of a thirteen‑year survey on 40‑year‑old patient D. with clinical manifestations of mitochondrial neurogastrointestinal encephalomyopathy syndrome associated with the previously undescribed missense mutation c.1301G>T (p.Gly434Val) of the TYMP gene. Detailed clinical picture (gastrointestinal dysfunction, cachexia, blepharoptosis, ophthalmoparesis, peripheral polyneuropathy and leukoaraiosis), electroneuromyography data (demyelination with secondary axonopathy), high blood serum level of dihydrothymine together with normal levels of thymidine and deoxyuridine made it possible to verify the diagnosis. Histopathological examination revealed atrophy of the longitudinal (outer) muscle layer of the small and large intestines and a significant decrease in the number of CD117+ cells (telocytes), signs of damage to the striated skeletal muscles of a mixed nature with a predominance of the myogenic pattern, as well the destruction of the myelin sheaths of peripheral nerves. Histochemical examination did not reveal “ragged red fibers” characteristic of mitochondrial pathology. Transmission electron microscopy demonstrated the presence of megalomitochondria in the myocardium.Синдром митохондриальной нейрогастроинтестинальной энцефаломиопатии – редкое (1–9:1000000, Orphanet, 2021) генетическое мультисистемное заболевание, обусловленное мутациями в ядерном гене TYMP, кодирующем фермент тимидинфосфорилазу.Представлены данные 13‑летнего наблюдения пациентки Д., 40 лет, с синдромом митохондриальной нейрогастроинтестинальной энцефаломиопатии, связанным с ранее не описанной миссенс‑заменой c.1301G>T (p.Gly434Val) в гене TYMP. Диагноз синдрома митохондриальной нейрогастроинтестинальной энцефаломиопатии был поставлен на основании клинических проявлений (дисфункция желудочно‑кишечного тракта, кахексия, блефароптоз, офтальмопарез, периферическая полинейропатия и лейкоэнцефалопатия), результатов электронейромиографии (демиелинизация с вторичной аксонопатией), а также повышения уровня дигидротимина в сыворотке крови при нормальных уровнях тимидина и дезоксиуридина. Патогистологическое исследование выявило атрофию продольного (наружного) мышечного слоя тонкой и толстой кишок и значимое уменьшение количества CD117+‑клеток (телоцитов), поражение скелетных мышц смешанного характера с преобладанием миогенного паттерна, а также деструкцию миелиновых оболочек периферических нервов. Исследование S100‑положительных вегетативных образований кишечной стенки не выявило патологических изменений. При гистохимическом исследовании не были обнаружены «рваные красные волокна», характерные для митохондриопатий. Трансмиссионная электронная микроскопия продемонстрировала наличие полиморфизма митохондрий кардиомиоцитов и мегаломитохондрий лейомиоцитов кишечника

Age of the Shirshov submarine ridge basement (Bering Sea) based on the results of investigation of zircons using the U-Pb SHRIMP method

The Shirshov Ridge holds an important position in the structure of the Bering Sea Basin. Stretching from north to south for over 500 km, it divides the Bering Sea into two deep water basins, the Aleutian and Komandorsky basins. The age of oceanic crust of the Aleutian basin based on linear magnetic anomalies is conventionally considered Early Cretaceous, of the Komandorsky basin — Miocene, according to the K-Ar dating of the basalts (9.8 Ma) exposed in 191 deep water drill borehole. Rocks belonging to the basement of the Shirshov Ridge were dredged during the 29th cruise of research vessel Dmitrii Mendeleev and are represented by amphibolitic gabbro whose composition is similar to that of gabbroids of mid-oceanic ridges. The age of metamorphism based on the results of K-Ar dating of amphibole is 47 ± 5 Ma. The U-Pb zircon dating method was used to determine the age of gabbro. Zircons were extracted from a ∼5 kg combined amphibolitic gabbroid sample, and the age of zircons was determined using a SHRIMP-II sensitive high resolution secondary ion microprobe (Center of Isotopic Studies, A.P. Karpinskii Russian Geological Research Institute, St. Petersburg). The average concordant age value for the 25 determinations performed based on 20 points for 18 grains is 72 ± 1.4 Ma (Late Campanian). For 5 grains, the measured age values are within the range of 88 ± 3.5 Ma to 126.5 ± 4.5 Ma. Given the western vergence of the thrust structure of the Shirshov Ridge, the acoustic basement of the Shirshov Ridge is most probably a complexly deformed oceanic crust of the Aleutian Trench, which most likely dates from the Early to Late Cretaceous

Interfaces in superconducting hybrid heterostructures with an antiferromagnetic interlayer

The structural, X-ray diffraction, and electrophysical studies of hybrid superconducting hetero-structures with an interlayer of cuprate antiferromagnetic Ca1 - x Sr (x) CuO2 (CSCO) with the upper electrode Nb/Au and the lower electrode Y(B)a(2)Cu(3)O(7 - delta) (YBCO) have been carried out. It has been experimentally shown that the epitaxial growth of two cuprates, YBCO and CSCO, results in the formation of an interface on which the enrichment of the CSCO interlayer with charge carriers proceeds to a depth of about 20 nm. In this case, the conduction of the enriched CSCO region proves to be closer to metallic, whereas the CSCO film deposited onto the NdGaO3 substrate is a Mott insulator with hopping conduction