Quantum spin chain as a potential realization of the Nersesyan-Tsvelik model

It is well established that long-range magnetic order is suppressed in magnetic systems whose interactions are low-dimensional. The prototypical example is the S-1/2 Heisenberg antiferromagnetic chain (S-1/2 HAFC) whose ground state is quantum critical. In real S-1/2 HAFC compounds interchain coupling induces long-range magnetic order although with a suppressed ordered moment and reduced N\'eel temperature compared to the Curie-Weiss temperature. Recently, it was suggested that order can also be suppressed if the interchain interactions are frustrated, as for the Nersesyan-Tsvelik model. Here, we study the new S-1/2 HAFC, (NO)[Cu(NO3)3]. This material shows extreme suppression of order which furthermore is incommensurate revealing the presence of frustration consistent with the Nersesyan-Tsvelik model

Полиморфизм групп крови яков в зависимости от окраса шерсти и комолости

Yaks of the Republic of Tyva are characterised by high biological diversity, expressed by a wide range of body colours and polymorphism of blood groups. According to the distribution of colour and polymorphic blood systems in bulls and yak dams, the most characteristic colours are black, black-and-white, and brown; their frequency in the population is 0.403, 0.148 and 0.118, respectively. Animals of other colour patterns were encountered with a frequency ranging from 0.004 to 0.091. Differentiation of yak bulls and dams by the presence or absence of horns showed that in polled bulls and dams, the frequency of markers Q, L', F of the blood systems B, C, F-V is higher (from 0.250 to 0.846) than in horned ones (0.100–0.500). Blood markers R2, W, X1, U' systems C, and S were identified in polled bulls and dams with a frequency of 0.018–0.143, not found in horned bulls and dams. The frequency of blood antigens G2, T2, I2, E'2, Y', J2 of systems B, J is higher in horned bulls and dams (from 0.200 to 0.800) than in polled individuals (0.054–0.464), and S1 of blood system S was detected only in horned queens. Blood markers I1, Y2, R2, W, X1, and U' systems B, C, and S were undetected in horned bulls and dams. In polled and horned bulls, the frequency of genes E'2, E, X2, V, Z of blood systems B, C, F-V, and Z is higher; they are detected with a frequency of 0.333 to 1.000, regardless of colour. Polled bulls of grey colour do not have markers A2, G2, I1, O2, Y', Y2, Q', Y', X1 blood systems A, B, C, and brown colour - A2, O2, Q', F, U, U' blood systems A, B, F-V, S. Still, in polled bulls with black and brown colours, blood antigens I1, X1 were identified, which are absent in horned individuals of different colours. In yaks, statistically significant differences were noted in colour, polledness and antigens A2, G2, I1, I2, Q, T2, E'2, I', Y', R2, W, X1, X2, L', F, V, J2, H', U, U', Z.Яки Республики Тыва характеризуются высоким биологическим разнообразием, выраженным широкой гаммой окраски туловища и полиморфизмом групп крови. По распределению масти и полиморфных систем крови у быков и маток яков наиболее характерными окрасками являются черная, чернопестрая, коричневая, их частота в популяции составляет 0,403; 0,148 и 0,118 соответственно. Животные других расцветок окраски встречались с частотой от 0,004 до 0,091. Дифференциация яков-быков и маток по наличию рогов или их отсутствию показала, что у комолых быков и маток частота маркеров Q, L', F систем крови B, C, F-V выше (от 0,250 до 0,846), чем у рогатых (0,100–0,500). Маркёры крови R2, W, Х1, U' систем C, S выявлены у комолых быков и маток с частотой 0,018–0,143, которых не оказалось у рогатых быков и маток. Частота антигенов крови G2, Т2, I2, Е'2, Y', J2 систем B, J выше у рогатых быков и маток (от 0,200 до 0,800), чем у комолых особей (0,054–0,464), а S1 системы крови S выявлен только у рогатых маток. Маркеры крови I1, Y2, R2, W, Х1, U' систем B, C, S не выявлены у рогатых быков и маток. У комолых и рогатых быков выше частота генов Е'2, Е, Х2, V, Z систем крови B, C, F-V, Z, они выявлены с частотой от 0,333 до 1,000 независимо от масти. Комолые быки серой масти не имеют маркеров А2, G2, I1, О2, Y', Y2, Q', Y', Х1 систем крови А, В, С, а коричневой окраски – А2, О2, Q', F, U, U' систем крови А, В, F-V, S, но у комолых быков с черной и коричневой окраской выявлены антигены крови I1, Х1, которые отсутствуют у рогатых особей с различной мастью. У яков отмечены статистически значимые отличия по окраске, комолости и антигенам A2, G2, I1, I2, Q, T2, Е'2, I', Y', R2, W, X1, X2, L',  F, V,  J2,  H', U, U',  Z

Electronic structure and magnetic properties of the strong-rung spin-1 ladder compound Rb3 Ni2(NO3)7

Rb3Ni2(NO3)7 was obtained by crystallization from anhydrous nitric acid solution of rubidium nitrate and nickel nitrate hexahydrate. The crystal structure determined on single crystals implies isolated spin-1 two-leg ladders of Ni2+ ions connected by (NO3)- groups as basic elements. Magnetic susceptibility, specific heat in magnetic fields up to 9 T, magnetization, and high-frequency electron spin resonance studies performed on powder samples show the absence of long-range magnetic order at T≥2 K. Electronic structure calculations and the detailed analysis of the experimental data enable quantitative estimates of the relevant parameters of the S=1 ladders in Rb3Ni2(NO3)7. The rung coupling J1=10.16 K, the leg coupling J2=1.5 K, and the Ising-type anisotropy |A|=8.6 K are obtained. The scenario of a valence-bond solidlike quantum ground state realized in the two-leg Ni2+ ladders is further corroborated by model simulations of the magnetic susceptibility. © 2018 American Physical Society

Clinical Recommendations of the Russian Scientific Liver Society and Russian Gastroenterological Association on Diagnosis and Treatment of Liver Fibrosis, Cirrhosis and Their Complications

Aim. Current clinical recommendations are intended to supply gastroenterologists, physicians and general practitioners with modern methods for the diagnosis and treatment of liver cirrhosis and fibrosis.Key points. Liver fibrosis develops with connective tissue accumulation in liver in the outcome of various chronic diseases, including alcohol misuse, viral hepatitises, autoimmune and more rare hereditary liver diseases. Liver cirrhosis is the final stage of most chronic diffuse liver diseases. The recommendations present current opinions on pathogenesis of liver fibrosis and cirrhosis, principles of diagnosis, treatment and prevention of their main complications: hepatic encephalopathy, oesophageal and gastric variceal bleeding, acute kidney injury/hepatorenal syndrome, infectious complications (i.a. spontaneous bacterial peritonitis), hyponatraemia, pulmonary complications, etc.Conclusion. Timely diagnosis and adequate therapy in cirrhosis can prevent life-threatening complications and improve the patients’ prognosis and quality of life

Co(NO3)2 as an Inverted Umbrella-type Chiral Noncoplanar Ferrimagnet

The low-dimensional magnetic systems tend to reveal exotic spin-liquid ground states or form peculiar types of long-range order. Among systems of vivid interest are those characterized by the triangular motif in two dimensions. The realization of either ordered or disordered ground state in triangular, honeycomb, or kagome lattices is dictated by the competition of exchange interactions, also being sensitive to anisotropy and the spin value of magnetic ions. While the low-spin Heisenberg systems may arrive to a spin-liquid long-range entangled quantum state with emergent gauge structures, the high-spin Ising systems may establish the rigid noncollinear structures. Here, we present the case of chiral noncoplanar inverted umbrella-type ferrimagnet formed in cobalt nitrate Co(NO3)2 below TC=3K with the comparable spin and orbital contributions to the total magnetic moment. © 2020 American Physical Society.This work has been supported by Russian Scientific Foundation, Grant No. 19-42-02010 and by Russian Foundation for Basic Research (RFBR) Grants No. 18-52-52005, No. 18-502-12022, No. 19-02-00015, and No. 19-03-01059. We acknowledge support by the Russian Ministry of Science and Higher Education, Contracts No. 02.A03.21.0004, No. 02.A03.21.0006, and No. 02.A03.21.0011. O.V.M. and A.N.V. acknowledge support by NUST “MISiS,” Grant No. K2-2020-008. We acknowledge the support of Hochfeld Magnetlabor Dresden at Helmholtz Zentrum Dresden Rossendorf, member of the European Magnetic Field Laboratory (EMFL). B.L. acknowledges the support of DFG through Project No. B06 of SFB 1143 (ID No. 247310070). J.-Y.L. was supported by Taiwan MOST Grant No. 107-2923-M-009-001-MY3 and by the center for Emergent Functional Matter Science of NCTU from the Featured Areas Research Center program within the framework of the Higher education Sprout Project by the Ministry of Education (MOE) in Taiwan. M.A.-H. acknowledges the support from the Swedish Research Council Grant No. (VR) 2018-05339. I.V.S. was supported by Program AAAA-A18-118020190095-4 (Quantum)

ВЛИЯНИЕ ЖЕНСКОЙ АУТОСЫВОРОТКИ КРОВИ НА АЛЛОГЕННЫЕ ВЗАИМОДЕЙСТВИЯ В КРАТКОСРОЧНОЙ КУЛЬТУРЕ ЛИМФОЦИТОВ СУПРУГОВ, ИМЕЮЩИХ ДЕТЕЙ С КОНОТРУНКАЛЬНЫМИ ПОРОКАМИ

Highlights The findings of this original study ensure the detection of violations in the humoral regulation of the maternal immune interactions with semiallogeneic fetus, considered as a risk factor for developing sporadic conotruncal heart malformations in the next generation.Aim To study the role of female autoserum blood in limiting allogeneic interactions in short-term lymphocyte cultures of parents having children with conotruncal heart malformations.Methods 21 married couples (the study group) with children suffering from conotrucnal heart malformations (Tetralogy of Fallot) without chromosomal diseases were examined. The control group consisted of 21 families with three or more healthy children. The immune response in a mixed lymphocyte culture of parents was assessed by the increase in HLA-DR expression in the mixed culture with respect to spontaneous lymphocyte cultures. Primary staining of female and male lymphocytes with monoclonal antibodies to CD45, conjugated with various fluorescent dyes (PC-5 and PC-7), allowed assessing the immune response of female lymphocytes to male and vice versa.Results The effects of female autoserum on the mixed lymphocyte culture of parents were assessed. The obtained results reported that the birth of children with conotruncal heart malformations is associated with the interfering effect of female autoserum on HLA-DR expression on subpopulations of female lymphocytes (CD3+, HLA-DR+) and the activating effect on subpopulations of female lymphocytes (CD3-, HLA-DR+). The observed role of female autoserum in the study group may be associated with the absence of HLA-DR-blocking autoantibodies and high synthesis of cytokines by T2 and T3 helper lymphocytes.Conclusion The effects of female autoserum on allogeneic lymphocyte interactions of parents may be observed in short-term mixed lymphocyte cultures. The evaluation of the activating and interfering effects ensures timely identification of any violations in the humoral regulation of the maternal immune interactions with the HLA semiallogenic fetus, considered as a risk factor for developing sporadic conotruncal heart malformations in the next generation.Основные положения Полученные данные оригинального исследования позволят выявлять нарушения в гуморальной регуляции иммунных взаимодействий матери и полуаллогенного по HLA эмбриона/плода, как фактора риска формирования спорадических пороков конотрункуса в последующем поколении.Цель Изучение роли женской аутосыворотки крови в ограничении аллогенных взаимодействий в краткосрочной культуре лимфоцитов супругов, имеющих детей с пороками конотрункуса.Материалы и методы Для выполнения поставленной цели обследована 21 семейная пара (основная группа), имеющая детей с пороками конотрункуса (тетрада Фалло) без хромосомных заболеваний. Контрольную группу составила 21 семья, имеющая трех и более здоровых детей. Иммунный ответ в смешанной культуре лимфоцитов (СКЛ) супругов оценивали по увеличению экспрессии HLA-DR в смешанной культуре по отношению к спонтанным культурам лимфоцитов. Первичная окраска женских и мужских лимфоцитов моноклональными антителами к CD45, конъюгированными с различными флуоресцентными красителями (PC-5 и PC-7), позволила оценить иммунный ответ женских лимфоцитов на мужские и наоборот.Результаты Проведена оценка эффекта женской аутосыворотки на СКЛ супругов. Результаты исследования показали, что рождение детей с пороками конотрункуса ассоциировано с блокирующим эффектом женской аутосыворотки в отношении экспрессии HLA-DR на субпопуляции женских лимфоцитов (CD3+, HLA-DR+) и активирующим эффектом на эти реакции в отношении субпопуляции женских лимфоцитов (CD3-, HLA-DR+). Эти эффекты женской аутосыворотки в опытной группе могут быть связаны с отсутствием блокирующих HLA-DR аутоантител и высоким синтезом цитокинов Т2- и Т3-хелперными лимфоцитами.Заключение В краткосрочной СКЛ отражаются эффекты женской аутосыворотки крови на аллогенные взаимодействия лимфоцитов супругов. Исследование коэффициента прироста и блокирующего коэффициента позволит выявлять нарушения в гуморальной регуляции иммунных взаимодействий матери и полуаллогенного по HLA эмбриона/плода, как фактора риска формирования спорадических пороков конотрункуса в последующем поколении.