Relativistic quark model and pentaquark spectroscopy

The relativistic five-quark equations are found in the framework of the dispersion relation technique. The solutions of these equations using the method based on the extraction of leading singularities of the amplitudes are obtained. The five-quark amplitudes for the low-lying pentaquarks are calculated under the condition that flavor SU(3) symmetry holds. The poles of five-quark amplitudes determine the masses of the lowest pentaquarks. The mass spectra of pentaquarks which contain only light quarks are calculated. The calculation of pentaquark amplitudes estimates the contributions of three subamplitudes. The main contributions to the pentaquark amplitude are determined by the subamplitudes, which include the meson states.Comment: 22 pages, pd

Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics

Large optical anisotropy observed in a broad spectral range is of paramount importance for efficient light manipulation in countless devices. Although a giant anisotropy was recently observed in the mid-infrared wavelength range, for visible and near-infrared spectral intervals, the problem remains acute with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN crystals. This inspired an intensive search for giant optical anisotropy among natural and artificial materials. Here, we demonstrate that layered transition metal dichalcogenides (TMDCs) provide an answer to this quest owing to their fundamental differences between intralayer strong covalent bonding and weak interlayer van der Walls interaction. To do this, we carried out a correlative far- and near-field characterization validated by first-principle calculations that reveals an unprecedented birefringence of 1.5 in the infrared and 3 in the visible light for MoS2. Our findings demonstrate that this outstanding anisotropy allows for tackling the diffraction limit enabling an avenue for on-chip next-generation photonics.Comment: 20 pages, 5 figure

High-refractive index and mechanically cleavable non-van der Waals InGaS3

The growing families of two-dimensional crystals derived from naturally occurring van der Waals materials offer an unprecedented platform to investigate elusive physical phenomena and could be of use in a diverse range of devices. Of particular interest are recently reported atomic sheets of non-van der Waals materials, which could allow a better comprehension of the nature of structural bonds and increase the functionality of prospective heterostructures. Here, we study the optostructural properties of ultrathin non-van der Waals InGaS3 sheets produced by standard mechanical cleavage. Our ab initio calculation results suggest an emergence of authentically delicate out-of-plane covalent bonds within its unit cell, and, as a consequence, an artificial generation of layered structure within the material. Those yield to singular layer isolation energies of around 50 meVA-2, which is comparable with the conventional van der Waals material's monolayer isolation energies of 20 - 60 meVA-2. In addition, we provide a comprehensive analysis of the structural, vibrational, and optical properties of the materials presenting that it is a wide bandgap (2.73 eV) semiconductor with a high-refractive index (higher than 2.5) and negligible losses in the visible and infrared spectral ranges. It makes it a perfect candidate for further establishment of visible-range all-dielectric nanophotonics

The clinical case of limb-girdle muscle dystrophy 2Q associated with myasthenic syndrome and lung damage

Limb-girdle muscle dystrophy 2Q is one of the rarest forms of plectinopathies and is represented by an isolated muscular dystrophic syndrome, according to two previously described literature reports. There are five forms of plectinopathies, including limb-girdle muscle dystrophy 2Q, are caused by mutations in the PLEC gene, the alternative splicing of which determines the synthesis of 9 isoforms of the plectin protein (1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 3) performing cytolinker function in the neuronal, epithelial and muscle tissue.The article describes the family observation of three sick siblings with the limb-girdle muscle dystrophy 2Q phenotype due to the presence of a new homozygous mutation (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) in the isoform 1f PLEC revealed by whole-exome sequencing. Clinical, electromyography, visualization and histopathological features of limb-girdle muscle dystrophy 2Q were analyzed in detail. The onset of clinical manifestations in all the described siblings was observed in early childhood with moderate weakness mainly in the pelvic girdle muscles and proximal lower limbs with minimal involvement of the muscles of the shoulder girdle. A distinctive aspect is the stagnation of the myodystrophic process until 20—21 years, followed by the progression and development of episodes of respiratory failure, as well as the formation of rigidity of the cervical, thoracic spine and moderate contracture of the Achilles tendons. Typical features are marked atrophy of paravertebral muscles with the formation of pterygoid scapula and the presence of hypertrophy m. gastrocnemius, m. quadriceps femoris, m. deltoideus and m. triceps brachii. Histopathological examination m. vastus lateralis revealed myodystrophic process without inflammatory infiltration, muscle fiber cytoskeleton disorganization resulted from the plectin loss.Electrocardiography signs of the early repolarization syndrome, focal cardiosclerosis and sinus tachycardia are described. For the first time, involvement in the pathological process of pulmonary tissue in the form of noninfectious bronchiolitis, atelectasis, and the development of the myasthenic syndrome causing episodes of respiratory failure resulted in the death of two described siblings aged 29 and 31 years. Discussed pathogenetic role of PLEC 1f isoform in the development of described syndromes, expands understanding of rare nosology limb-girdle muscle dystrophy 2Q

Three-Nucleon Forces from Chiral Effective Field Theory

We perform the first complete analysis of nd scattering at next-to-next-to-leading order in chiral effective field theory including the corresponding three-nucleon force and extending our previous work, where only the two-nucleon interaction has been taken into account. The three-nucleon force appears first at this order in the chiral expansion and depends on two unknown parameters. These two parameters are determined from the triton binding energy and the nd doublet scattering length. We find an improved description of various scattering observables in relation to the next-to-leading order results especially at moderate energies (E_lab = 65 MeV). It is demonstrated that the long-standing A_y-problem in nd elastic scattering is still not solved by the leading 3NF, although some visible improvement is observed. We discuss possibilities of solving this puzzle. The predicted binding energy for the alpha-particle agrees with the empirical value.Comment: 36 pp, 20 figure

Benchmark Test Calculation of a Four-Nucleon Bound State

In the past, several efficient methods have been developed to solve the Schroedinger equation for four-nucleon bound states accurately. These are the Faddeev-Yakubovsky, the coupled-rearrangement-channel Gaussian-basis variational, the stochastic variational, the hyperspherical variational, the Green's function Monte Carlo, the no-core shell model and the effective interaction hyperspherical harmonic methods. In this article we compare the energy eigenvalue results and some wave function properties using the realistic AV8' NN interaction. The results of all schemes agree very well showing the high accuracy of our present ability to calculate the four-nucleon bound state.Comment: 17 pages, 1 figure

Relativistic five-quark equations and hybrid baryon spectroscopy

The relativistic five-quark equations are found in the framework of the dispersion relation technique. The behavior of the low-energy five-particle amplitude is determined by its leading singularities in the pair invariant masses. The solutions of these equations using the method based on the extraction leading singularities of the amplitudes are obtained. The mass spectra of nucleon and delta-isobar hybrid baryons are calculated. The calculations of hybrid baryon amplitudes estimate the contributions of four subamplitudes. The main contributions to the hybrid baryon amplitude are determined by the subamplitudes, which include the excited gluon states.Comment: 22 pages, pdf, minor changes in text and reference

Клинический случай поясно-конечностной мышечной дистрофии 2Q, ассоциированной с миастеническим синдромом и поражением легких

Limb-girdle muscle dystrophy 2Q is one of the rarest forms of plectinopathies and is represented by an isolated muscular dystrophic syndrome, according to two previously described literature reports. There are five forms of plectinopathies, including limb-girdle muscle dystrophy 2Q, are caused by mutations in the PLEC gene, the alternative splicing of which determines the synthesis of 9 isoforms of the plectin protein (1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 3) performing cytolinker function in the neuronal, epithelial and muscle tissue.The article describes the family observation of three sick siblings with the limb-girdle muscle dystrophy 2Q phenotype due to the presence of a new homozygous mutation (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) in the isoform 1f PLEC revealed by whole-exome sequencing. Clinical, electromyography, visualization and histopathological features of limb-girdle muscle dystrophy 2Q were analyzed in detail. The onset of clinical manifestations in all the described siblings was observed in early childhood with moderate weakness mainly in the pelvic girdle muscles and proximal lower limbs with minimal involvement of the muscles of the shoulder girdle. A distinctive aspect is the stagnation of the myodystrophic process until 20—21 years, followed by the progression and development of episodes of respiratory failure, as well as the formation of rigidity of the cervical, thoracic spine and moderate contracture of the Achilles tendons. Typical features are marked atrophy of paravertebral muscles with the formation of pterygoid scapula and the presence of hypertrophy m. gastrocnemius, m. quadriceps femoris, m. deltoideus and m. triceps brachii. Histopathological examination m. vastus lateralis revealed myodystrophic process without inflammatory infiltration, muscle fiber cytoskeleton disorganization resulted from the plectin loss.Electrocardiography signs of the early repolarization syndrome, focal cardiosclerosis and sinus tachycardia are described. For the first time, involvement in the pathological process of pulmonary tissue in the form of noninfectious bronchiolitis, atelectasis, and the development of the myasthenic syndrome causing episodes of respiratory failure resulted in the death of two described siblings aged 29 and 31 years. Discussed pathogenetic role of PLEC 1f isoform in the development of described syndromes, expands understanding of rare nosology limb-girdle muscle dystrophy 2Q.Поясно-конечностная мышечная дистрофия 2Q является одной из наиболее редких форм плектинопатий и проявляется изолированным мышечным дистрофическим синдромом согласно двум ранее представленным в литературе описаниям. Пять существующих форм плектинопатий, в том числе поясно-конечностная мышечная дистрофия 2Q, обусловлены мутациями в гене PLEC, альтернативный сплайсинг которого определяет синтез 9 изоформ белка плектина (1, 1а, 1b, 1c, 1d, 1е, 1f,1g, 3), выполняющих цитолинкерную функцию в нейрональной, эпителиальной и мышечной тканях.В статье представлено описание семейного наблюдения 3 больных сибсов с поясно-конечностной мышечной дистрофией 2Q, обусловленного наличием новой гомозиготной мутации (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) в изоформе 1f гена PLEC, выявленной с помощью полноэкзомного секвенирования. Детально проанализированы клинические, электронейромиографические, визуализационные и патогистологические особенности поясно-конечностной мышечной дистрофии 2Q. Дебют клинических проявлений у всех описанных членов семьи наблюдался в раннем детском возрасте в виде умеренной слабости преимущественно мышц тазового пояса и проксимальных отделов ног с минимальным вовлечением мышц плечевого пояса. Отличительным аспектом является стагнация миодистрофического процесса до 20—21 года с последующим прогрессированием и развитием эпизодов дыхательной недостаточности, а также формированием ригидности шейного, грудного отдела позвоночника и умеренной контрактуры ахилловых сухожилий. Характерными являются выраженная атрофия mm. paravertebralis с формированием крыловидных лопаток и наличие гипертрофии m. gastrocnemius, m. quadriceps femoris, m. deltoideus и m. triceps brachii. Патогистологическое исследование m. vastus lateralis отражает наличие миодистрофического процесса без воспалительной инфильтрации, дезорганизацию цитоскелета мышечных волокон и утрату плектина. Описаны электрокардиографические признаки синдрома ранней реполяризации, очагового кардиосклероза и синусовой тахикардии. Впервые в литературе представлено сочетание пояс-но-конечностной мышечной дистрофии 2Q с поражением легких в виде неинфекционного бронхиолита, ателектазов и развитием миастенического синдрома, обусловливающими эпизоды дыхательной недостаточности и повлекшие смерть 2 описываемых сибсов в возрасте 29 и 31 года. Обсуждаемое патогенетическое значение 1f-изоформы плектина в развитии описанных синдромов позволяет расширить представление о редкой нозологии — поясно-конечностной мышечной дистрофии 2Q

Model of the SARS-CoV-2 Virus for Development of a DNA-Modified, Surface-Enhanced Raman Spectroscopy Sensor with a Novel Hybrid Plasmonic Platform in Sandwich Mode

The recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has posed a great challenge for the development of ultra-fast methods for virus identification based on sensor principles. We created a structure modeling surface and size of the SARS-CoV-2 virus and used it in comparison with the standard antigen SARS-CoV-2—the receptor-binding domain (RBD) of the S-protein of the envelope of the SARS-CoV-2 virus from the Wuhan strain—for the development of detection of coronaviruses using a DNA-modified, surface-enhanced Raman scattering (SERS)-based aptasensor in sandwich mode: a primary aptamer attached to the plasmonic surface—RBD-covered Ag nanoparticle—the Cy3-labeled secondary aptamer. Fabricated novel hybrid plasmonic structures based on “Ag mirror-SiO2-nanostructured Ag” demonstrate sensitivity for the detection of investigated analytes due to the combination of localized surface plasmons in nanostructured silver surface and the gap surface plasmons in a thin dielectric layer of SiO2 between silver layers. A specific SERS signal has been obtained from SERS-active compounds with RBD-specific DNA aptamers that selectively bind to the S protein of synthetic virion (dissociation constants of DNA-aptamer complexes with protein in the range of 10 nM). The purpose of the study is to systematically analyze the combination of components in an aptamer-based sandwich system. A developed virus size simulating silver particles adsorbed on an aptamer-coated sensor provided a signal different from free RBD. The data obtained are consistent with the theory of signal amplification depending on the distance of the active compound from the amplifying surface and the nature of such a compound. The ability to detect the target virus due to specific interaction with such DNA is quantitatively controlled by the degree of the quenching SERS signal from the labeled compound. Developed indicator sandwich-type systems demonstrate high stability. Such a platform does not require special permissions to work with viruses. Therefore, our approach creates the promising basis for fostering the practical application of ultra-fast, amplification-free methods for detecting coronaviruses based on SARS-CoV-2