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1.
Phys Rev Lett ; 132(21): 211804, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38856254

RESUMO

We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(X_{τ/ℓ})≡B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189 fb^{-1} of electron-positron collision data collected with the Belle II detector. We find R(X_{τ/ℓ})=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(X_{τ/ℓ}).

2.
Phys Rev Lett ; 132(23): 231903, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38905689

RESUMO

The cross section of the process e^{+}e^{-}→π^{+}π^{-} has been measured in the center-of-mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The measurement is based on an integrated luminosity of about 88 pb^{-1}, of which 62 pb^{-1} represent a complete dataset collected by CMD-3 at center-of-mass energies below 1 GeV. In the dominant region near the ρ resonance a systematic uncertainty of 0.7% was achieved. The implications of the presented results for the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon are discussed.

3.
Bull Exp Biol Med ; 176(6): 751-755, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38896322

RESUMO

The removal of double-stranded RNA (dsRNA) contaminants during in vitro mRNA synthesis is one of the technological problems to be solved. Apparently, these contaminants are the result of the T7 RNA polymerase side activity. In this study, we used a modified method of mRNA purification based on the selective binding of dsRNA to cellulose in ethanol-containing buffer. It was shown both in vivo and in vitro that the cellulose-purified mRNA preparation leads neither to activation of the lymphocyte inflammatory marker CD69 nor to increased release of IFNα in mice, and does not contain impurities detectable by antibodies to dsRNA.


Assuntos
RNA de Cadeia Dupla , RNA Mensageiro , Animais , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , Camundongos , Antígenos de Diferenciação de Linfócitos T/metabolismo , Antígenos de Diferenciação de Linfócitos T/genética , Antígenos CD/genética , Antígenos CD/metabolismo , Lectinas Tipo C/metabolismo , Lectinas Tipo C/genética , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Interferon-alfa/genética , Interferon-alfa/metabolismo , Interferon-alfa/biossíntese , Proteínas Virais/metabolismo , Proteínas Virais/genética
4.
Phys Rev Lett ; 131(24): 241001, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38181145

RESUMO

A recent discovery of additional mechanism of electroluminescence (EL) in noble gases due to the neutral bremsstrahlung (NBrS) effect led to a prediction that NBrS EL should be present in noble liquids as well. A theoretical model of NBrS EL in noble liquids was developed accordingly in the frameworks of Cohen-Lekner and Atrazhev. In this work, we confirm this prediction: For the first time, visible-range EL has been observed in liquid argon at electric fields reaching 90 kV/cm, using gas electron multiplier (GEM) and thick GEM structures. Absolute light yields of the EL were measured and found to be in excellent agreement with the theory, provided that the momentum-transfer cross section of electron scattering is used for calculation of the NBrS cross section (instead of the energy-transfer one).

5.
Phys Rev Lett ; 131(11): 111803, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37774261

RESUMO

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6} BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

6.
Phys Rev Lett ; 131(17): 171803, 2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37955504

RESUMO

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207 fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9) fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

7.
Phys Rev Lett ; 131(18): 181801, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37977641

RESUMO

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189 fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

8.
Phys Rev Lett ; 131(2): 021801, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37505960

RESUMO

We report the first measurement of the Michel parameter ξ^{'} in the τ^{-}→µ^{-}ν[over ¯]_{µ}ν_{τ} decay with a new method proposed just recently. The measurement is based on the reconstruction of the τ^{-}→µ^{-}ν[over ¯]_{µ}ν_{τ} events with subsequent muon decay in flight in the Belle central drift chamber. The analyzed data sample of 988 fb^{-1} collected by the Belle detector corresponds to approximately 912×10^{6} τ^{+}τ^{-} pairs. We measure ξ^{'}=0.22±0.94(stat)±0.42(syst), which is in agreement with the standard model prediction of ξ^{'}=1. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.

9.
Biochemistry (Mosc) ; 85(7): 781-791, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33040722

RESUMO

For the first time, the chymosin gene (CYM) of a maral was characterized. Its exon/intron organization was established using comparative analysis of the nucleotide sequence. The CYM mRNA sequence encoding a maral preprochymosin was reconstructed. Nucleotide sequence of the CYM maral mRNA allowed developing an expression vector to ensure production of a recombinant enzyme. Recombinant maral prochymosin was obtained in the expression system of Escherichia coli [strain BL21 (DE3)]. Total milk-coagulation activity (MCA) of the recombinant maral chymosin was 2330 AU/ml. The recombinant maral prochymosin relative activity was 52955 AU/mg. The recombinant maral chymosin showed 100-81% MCA in the temperature range 30-50°C, thermal stability (TS) threshold was 50°C, and the enzyme was completely inactivated at 70°C. Preparations of the recombinant chymosin of a single-humped camel and recombinant bovine chymosin were used as reference samples. Michaelis-Menten constant (Km), turnover number (kcat), and catalytic efficiency (kcat/Km) of the recombinant maral chymosin, were 1.18 ± 0.1 µM, 2.68 ± 0.08 s-1 and 2.27± 0.10 µm M-1·s-1, respectively.


Assuntos
Quimosina/genética , Quimosina/metabolismo , Cervos/genética , Animais , Sequência de Bases , Quimosina/química , Cervos/metabolismo , Proteínas Recombinantes/química
10.
Stomatologiia (Mosk) ; 99(6): 7-12, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33267536

RESUMO

OBJECTIVE: To give a quantitative and qualitative characteristic of the structure of the enamel's mineral component structure of impacted teeth with or without connective tissue dysplasia in different periods of early postnatal human ontogenesis using densitometry and atomic force microscopy. MATERIALS AND METHODS: The study involved 120 males with and without connective tissue dysplasia (CTD), which were divided into 3 equal subgroups (60 people with CTD and 60 people without CTD), 20 people in each, according to age: 15-20, 21-30, 31-40 years old. Each of the examined was removed either 3.8 or 4.8 tooth. To study the inorganic component of tooth enamel, a densitometric assessment of enamel's optical density was carried out using computed tomography in the Kodak Dental Systems software (Trophy 2000) and preparation of thin sections of tooth samples 3.8 or 4.8 for atomic force microscopy (AFM) according to the methods of Omsk State Medical University. RESULTS: The structure of tooth enamel in connective tissue dysplasia in the early postpartum period of ontogenesis is characterized by pronounced polymorphisms and an insufficient level of maturity. The ordering and orientation of the enamel prisms are disturbed due to insufficient packing density and a large distance between the enamel prisms at the age of 15-20, 21-30. The established changes indicate the incomplete nature of amelogenesis with connective tissue dysplasia at the indicated ages. CONCLUSIONS: In case of connective tissue dysplasia in the early postnatal period of ontogenesis, an incomplete amelogenesis is observed. This process is manifested by lower values of the mineral component's optical density, low packing of enamel prisms, a large distance between enamel prisms and their irregular shape.


Assuntos
Esmalte Dentário , Minerais , Adulto , Tecido Conjuntivo , Densitometria , Esmalte Dentário/diagnóstico por imagem , Feminino , Humanos , Recém-Nascido , Masculino , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Período Pós-Parto , Pesquisa
11.
Phys Rev Lett ; 122(8): 082001, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30932568

RESUMO

We present the first measurements of absolute branching fractions of Ξ_{c}^{0} decays into Ξ^{-}π^{+}, ΛK^{-}π^{+}, and pK^{-}K^{-}π^{+} final states. The measurements are made using a dataset comprising (772±11)×10^{6} BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. We first measure the absolute branching fraction for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} using a missing-mass technique; the result is B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})=(9.51±2.10±0.88)×10^{-4}. We subsequently measure the product branching fractions B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→Ξ^{-}π^{+}), B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→ΛK^{-}π^{+}), and B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+}) with improved precision. Dividing these product branching fractions by the result for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} yields the following branching fractions: B(Ξ_{c}^{0}→Ξ^{-}π^{+})=(1.80±0.50±0.14)%, B(Ξ_{c}^{0}→ΛK^{-}π^{+})=(1.17±0.37±0.09)%, and B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+})=(0.58±0.23±0.05)%. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for B(Ξ_{c}^{0}→Ξ^{-}π^{+}) can be combined with Ξ_{c}^{0} branching fractions measured relative to Ξ_{c}^{0}→Ξ^{-}π^{+} to yield other absolute Ξ_{c}^{0} branching fractions.

12.
Extremophiles ; 23(5): 599-612, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376001

RESUMO

A novel thermophilic bacteriophage AP45 and its host strain Aeribacillus sp. CEMTC656 were isolated from the Valley of Geysers, Kamchatka Peninsula, Russia. Bacteriophage AP45 was identified as a member of the Siphoviridae family by electron microscopy. It showed high thermostability and had a slow cycle of reproduction. The AP45 genome had 51,606 base pairs (bp) and contained 71 open reading frames (ORFs), 40 of them encoding proteins of predicted function. Genes encoding DNA and RNA polymerases were not identified, indicating that AP45 used host polymerases. Based on the ORF65 encoding putative endolysin, the recombinant protein rAP45Lys was developed and its peptidoglycan-hydrolyzing activity was demonstrated. The AP45 genome exhibited limited identity to other phage sequences; the highest identity, 36%, was with the genome of the thermophilic Geobacillus myovirus D6E. The majority of putative proteins encoded by the AP45 genome had higher similarity to proteins from bacteria belonging to the Bacillaceae family, than to bacteriophages. In addition, more than half of the putative ORFs in the AP45 genome were highly similar to prophage sequences of A. pallidus strain 8m3, which was isolated in north-east China. The AP45 phage and revealed prophages might be members of a new genus belonging to the Siphoviridae family.


Assuntos
Bacillaceae/virologia , Genoma Viral , Siphoviridae/genética , Termotolerância , Fontes Termais/microbiologia , Fontes Termais/virologia , Fases de Leitura Aberta , Filogenia , Siphoviridae/classificação , Siphoviridae/patogenicidade
13.
Adv Gerontol ; 32(1-2): 45-54, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31228367

RESUMO

The hypothesis of dependence of the functional characterizations of bone marrow cells (BMC) - proliferation rate, direction proliferation, etc. - not only by the age of animals, but also on features of BMC microenvironment was verified. Two methods of changing the microenvironment were used. There were in vivo (induction of liver fibrosis in young and old animals) and in vitro (transfer of young and old animals BMC obtained in intact animals and animals with fibrosis into the same standard culture system). CuSO4-induced liver fibrosis and CCl4-induced liver fibrosis had a different effect on the ratio of cell types in the bone marrow in young and old animals. Thus, in young animals, regardless of the type of liver fibrosis inducer, the relative number of morphologically identifiable cell types decreased. This was accompanied by an increase in the number of identified cell types against the background of CuSO4-induced liver fibrosis and did not change against the background of CCl4-induced liver fibrosis in old animals. The proliferative activity of BMC isolated from old animals and transferred to an in vitro culture was superior to that of young animals. This is due to the large number of lymphocytes in the bone marrow of old animals by 167% and the specific composition and characteristics of the BMC microenvironment in old animals.


Assuntos
Envelhecimento , Células da Medula Óssea , Cirrose Hepática , Envelhecimento/fisiologia , Animais , Células da Medula Óssea/fisiologia
14.
Phys Rev Lett ; 121(6): 062001, 2018 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-30141661

RESUMO

We report the first observation of the hadronic transition ϒ(4S)→η^{'}ϒ(1S), using 496 fb^{-1} data collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We reconstruct the η^{'} meson through its decays to ρ^{0}γ and to π^{+}π^{-}η, with η→γγ. We measure B(ϒ(4S)→η^{'}ϒ(1S))=[3.43±0.88(stat)±0.21(syst)]×10^{-5}, with a significance of 5.7σ.

15.
Phys Rev Lett ; 121(26): 261801, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30636113

RESUMO

We present first evidence that the cosine of the CP-violating weak phase 2ß is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2ß=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2ß=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle ß of the CKM Unitarity Triangle is ß=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2ß>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-ß=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.

16.
Phys Rev Lett ; 121(23): 232001, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30576207

RESUMO

We report the observation of ϒ(2S)→γη_{b}(1S) decay based on an analysis of the inclusive photon spectrum of 24.7 fb^{-1} of e^{+}e^{-} collisions at the ϒ(2S) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure a branching fraction of B[ϒ(2S)→γη_{b}(1S)]=(6.1_{-0.7-0.6}^{+0.6+0.9})×10^{-4} and derive an η_{b}(1S) mass of 9394.8_{-3.1-2.7}^{+2.7+4.5} MeV/c^{2}, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.

17.
Phys Rev Lett ; 121(5): 052003, 2018 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-30118260

RESUMO

Using data recorded with the Belle detector, we observe a new excited hyperon, an Ω^{*-} candidate decaying into Ξ^{0}K^{-} and Ξ^{-}K_{S}^{0} with a mass of 2012.4±0.7(stat)±0.6(syst) MeV/c^{2} and a width of Γ=6.4_{-2.0}^{+2.5}(stat)±1.6(syst) MeV. The Ω^{*-} is seen primarily in ϒ(1S),ϒ(2S), and ϒ(3S) decays.

18.
Phys Rev Lett ; 121(5): 052001, 2018 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-30118290

RESUMO

Exclusive measurements of the quasifree pp→ppπ^{+}π^{-} reaction have been carried out at WASA@COSY by means of pd collisions at T_{p}=1.2 GeV. Total and differential cross sections have been extracted covering the energy region T_{p}=1.08-1.36 GeV, which is the region of N^{*}(1440) and Δ(1232)Δ(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor ΔN dibaryon resonance with I(J^{P})=2(1^{+}) produced associatedly with a pion is able to overcome these deficiencies.

19.
Phys Rev Lett ; 120(2): 022002, 2018 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-29376676

RESUMO

Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction p[over →]p→ppη has been measured close to threshold to explore the analyzing power A_{y}. The angular distribution of A_{y} is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q=15 MeV, signaling s-wave production with no evidence for higher partial waves. At Q=72 MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)^{2} and Ss^{*}Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the η meson.

20.
Phys Rev Lett ; 118(21): 211801, 2017 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-28598663

RESUMO

We report the first measurement of the τ lepton polarization P_{τ}(D^{*}) in the decay B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ} as well as a new measurement of the ratio of the branching fractions R(D^{*})=B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}), where ℓ^{-} denotes an electron or a muon, and the τ is reconstructed in the modes τ^{-}→π^{-}ν_{τ} and τ^{-}→ρ^{-}ν_{τ}. We use the full data sample of 772×10^{6} BB[over ¯] pairs recorded with the Belle detector at the KEKB electron-positron collider. Our results, P_{τ}(D^{*})=-0.38±0.51(stat)_{-0.16}^{+0.21}(syst) and R(D^{*})=0.270±0.035(stat)_{-0.025}^{+0.028}(syst), are consistent with the theoretical predictions of the standard model.

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