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The Landau–Yang theorem is sometimes formulated as a selection rule forbidding two real (that is, non-virtual) photons with zero total momentum to be in the state of the total angular momentum J = 1. In this paper, we discuss whether the theorem itself and this particular formulation can be extended to a pair of two twisted photons, which carry orbital angular momentum with respect to their propagation direction. We point out possible sources of confusion, which may arise both from the unusual features of twisted photons and from the fact that usual proofs of the Landau–Yang theorem operate in the center of motion reference frame, which, strictly speaking, exists only for plane waves. We show with an explicit calculation that a pair of twisted photons does have a non-zero overlap with the J = 1 state. What is actually forbidden is production of a spin-1 particle by such a photon pair, and in this formulation the Landau–Yang theorem is rock-solid. Although both the twisted photon pair and the spin-1 particle can exist in the J = 1 state, these two systems just cannot be coupled in a gauge-invariant and Lorentz invariant manner respecting Bose symmetry. [ABSTRACT FROM AUTHOR]

Abstract The Higgs potentials of extended Higgs sectors exhibit a complex and interesting vacuum structure. When travelling back in time, i.e. going to higher temperatures, the structure may change and exhibit interesting phase patterns and sequences of phases related to the respective minima of the potential. The investigation of the vacuum structure can give us indirect insights in beyond-Standard-Model physics and the evolution of the Universe. In this paper, we investigate the possibility of an intermediate charge-breaking (CB) phase in the 2-Higgs-Doublet Model (2HDM) type I. The existence has been reported previously by using a simple potential setup. We here confirm that the intermediate CB phase can still exist when using the one-loop corrected effective potential including thermal masses. We discuss its features and the relation with SU(2) symmetry (non-)restoration as well as its consistency with the current experimental data. Lastly, we show for some selected benchmark points the rich and interesting phase patterns and sequences that the 2HDM can undergo during its evolution from the early Universe to today’s electroweak vacuum.

Abstract Multi-Higgs models equipped with global symmetry groups, either exact or softly broken, offer a rich framework for constructions beyond the Standard Model and lead to remarkable phenomenological consequences. Knowing all the symmetry options within each class of models can guide its phenomenological exploration, as confirmed by the vast literature on the two- and three-Higgs-doublet models. Here, we begin a systematic study of finite non-abelian symmetry groups which can be imposed on the scalar sector of the four-Higgs-doublet model (4HDM) without leading to accidental symmetries. In this work, we derive the full list of such non-abelian groups available in the 4HDM that can be constructed as extensions of cyclic groups by their automorphism groups. This list is remarkably restricted but it contains cases which have not been previously studied. Since the methods we develop may prove useful for other classes of models, we present them in a pedagogical manner.

The aim of this study is to determine changes in the near-surface layer of ZrO _2 ceramics caused by irradiation with low-energy He ^2+ ions, as well as the associated formation of defects and structural deformations. During the experimental work conducted, it was established that the accumulation of deformation-structural distortions is of two stage nature, having a direct dependence on irradiation fluence and, therefore, on atomic displacement value. It was determined that at small atomic displacement values (less than 10 dpa), the main mechanisms of structural distortions are caused by tensile residual stresses, the value of which is less than 0.1 GPa. At the same time, the deformation distortion of chemical bonds has a pronounced anisotropy associated with a more pronounced distortion of the Zr–O _I chemical bonds, the distortion of which results in the formation of vacancy defects in the form of V _O . During determination of alterations in optical characteristics depending on the atomic displacement value, it was found that the dominant role at small values of dpa (less than 10 dpa) is played by point defects, which influence the formation of obstacles in the form of absorbing centers. In this case, an increase in the irradiation fluence above 10 ^17 ion cm ^−2 results in a growth in the linear refractive index, the change of which has a direct correlation with the value of residual stresses in the damaged layer. Certain dependencies of changes in structural features and their relationship with deformation distortions, as well as the accumulation of vacancy defects, can subsequently be used to predict the potential of using these ceramics as materials for new generation nuclear reactors.

Polyscias fruticosa (L.) Harms, or Ming aralia, is a medicinal plant of the Araliaceae family, which is highly valued for its antitoxic, anti-inflammatory, analgesic, antibacterial, anti-asthmatic, adaptogenic, and other properties. The plant can be potentially used to treat diabetes and its complications, ischemic brain damage, and Parkinson’s disease. Triterpene glycosides of the oleanane type, such as 3-O-[β-D-glucopyranosyl-(1→4)-β-D-glucuronopyranosyl] oleanolic acid 28-O-β-D-glucopyranosyl ester (PFS), ladyginoside A, and polysciosides A-H, are mainly responsible for biological activities of this species. In this study, cultivation of the cell suspension of P. fruticosa in 20 L bubble-type bioreactors was attempted as a sustainable method for cell biomass production of this valuable species and an alternative to overexploitation of wild plant resources. Cell suspension cultivated in bioreactors under a semi-continuous regime demonstrated satisfactory growth with a specific growth rate of 0.11 day−1, productivity of 0.32 g (L · day)−1, and an economic coefficient of 0.16 but slightly lower maximum biomass accumulation (~6.8 g L−1) compared to flask culture (~8.2 g L−1). Triterpene glycosides PFS (0.91 mg gDW−1) and ladyginoside A (0.77 mg gDW−1) were detected in bioreactor-produced cell biomass in higher concentrations compared to cells grown in flasks (0.50 and 0.22 mg gDW−1, respectively). In antibacterial tests, the minimum inhibitory concentrations (MICs) of cell biomass extracts against the most common pathogens Staphylococcus aureus, methicillin-resistant strain MRSA, Pseudomonas aeruginosa, and Escherichia coli varied within 250–2000 µg mL−1 which was higher compared to extracts of greenhouse plant leaves (MIC = 4000 µg mL−1). Cell biomass extracts also exhibited antioxidant activity, as confirmed by DPPH and TEAC assays. Our results suggest that bioreactor cultivation of P. fruticosa suspension cell culture may be a perspective method for the sustainable biomass production of this species.

Abstract We develop methods to study the scalar sector of multi-Higgs models with large discrete symmetry groups that are softly broken. While in the exact symmetry limit, the model has very few parameters and can be studied analytically, proliferation of quadratic couplings in the most general softly broken case makes the analysis cumbersome. We identify two sets of soft breaking terms which play different roles: those which preserve the symmetric vacuum expectation value alignment, and the remaining terms which shift it. Focusing on alignment preserving terms, we check which structural features of the symmetric parent model are conserved and which are modified. We find remarkable examples of structural features which are inherited from the parent symmetric model and which persist even when no exact symmetry is left. The general procedure is illustrated with the example of the three-Higgs-doublet model with the softly broken symmetry group $$\Sigma (36)$$ Σ ( 36 ) .

Background. In relation with the COVID-19 new coronavirus infection epidemic that began in Russia in the spring of 2020, a completely new group of patients appeared: patients whose coronavirus infection was combined with the proximal femur fractures. In the course of practical work, hospital doctors had to gain experience in treating these complex patients, solve new organizational and medical tasks. The aim of the study was to evaluate the results of treatment of patients with the proximal femur fractures in combination with coronavirus infection in a covid hospital at the hospital stage, 30-day and 6-month terms. Materials and Methods. The retrospective study is based on the collection and generalization of data from 64 patients with the proximal femur fractures in combination with confirmed coronavirus infection who underwent inpatient treatment from 16.03.2020 to 31.05.2021. 38 (59.4%) patients had a femoral neck fracture, 26 (40.6%) had a fracture of the trochanter region. Forty (62.5%) patients underwent surgical treatment (hip replacement was performed in 23 cases, osteosynthesis was performed in 17 cases), 24 (37.5%) patients did not undergo surgery. Results. With conservative treatment, the hospital mortality rate was 41.6%, the 30-day mortality rate was 72.7%, and the 6 month mortality rate was 95.5%. During surgical treatment, the hospital mortality rate was 5.0% (2 patients died). Early postoperative complications were detected in 5 (12.5%) patients. Thirty-one (77.5%) patients walked or stood with a walker on their own at the time of discharge; 7 (17.5%) patients could not be activated. The thirty-day mortality rate in the group of patients who underwent surgical treatment was 8.6%, and the 6-month mortality rate was 32.1%. Conclusion. Surgical treatment of patients with the proximal femur fractures in combination with coronavirus infection is much more difficult than the treatment of patients without infectious pathology. However, despite number of unresolved problems, surgical treatment of such patients is possible with good results and should be actively applied.

Abstract We discuss a rather common but often unnoticed pitfall which arises when deriving the bounded-from-below (BFB) conditions in multi-Higgs models with softly broken global symmetries. Namely, necessary and sufficient BFB conditions derived for the case with an exact symmetry can be ruined by introducing soft symmetry breaking terms. Using S 4 and A 4-symmetric three-Higgs-doublet models as an example, we argue that all published necessary and sufficient BFB conditions, even those which are correct for the exactly symmetric case, are no longer sufficient if soft symmetry breaking is added. Using the geometric formalism, we derive the exact necessary and sufficient BFB conditions for the 3HDM with the symmetry group S 4, either exact or softly broken, and review the situation for the A 4-symmetric case.

Aim. Determine whether bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry can be used as predictor of increased risk of death in hemodialysis patients. Materials and methods. A prospective study was performed of 516 patients with chronic kidney disease treated with hemodialysis (men 265, women 251, mean age 44.811.4 years) who were observed for 5.73.2 years. Before inclusion in the study, in all patients was analyzed bone mineral density using dual-energy X-ray absorptiometry in three standard departments: lumbar vertebrae, proximal femur and distal forearm. The probability analysis of the outcome was carried out using the KaplanMeier method and Cox. Results. During follow-up period 111 (21.5%) patients died, 50.5% from cardiovascular events. Survival analysis by KaplanMeier method allowed to prove the increased risk of death from cardiovascular pathology in hemodailysis patients with low bone mineral density of all evaluated areas. Step-by-step multivariate Cox regression analysis showed that the T score of the femur, showing the difference of BMD of the patient with normal value of BMD for young adult, had the greatest prognostic significance. Conclusion. Reduced bone mineral density in patients receiving hemodialysis is associated with an increased risk of death from cardiovascular disease. Dual energy x-ray absorptiometry can be used for assessment of this risk.

The main periods of life, scientific and state activity of Vasilij Markovich Florinsky. The purpose of the article is to consider stages of V.M. Florinsky’s activity in the academy as a pupil, scientist and statesman and to show his role in the development of obstetrics and gynaecology, anthropology, ethnography, history of medicine and folk medicine, as well as his contribution to the formation of eugenics and medical genetics. During the study the following methods were applied: theoretical, analysis, biographical. V.M. Florinsky published more than 330 scientific works. He published about 30 scientific publications on various sections of obstetrics and gynaecology. The scientist proposed an original method to prevent ruptures of the perineum during childbirth, among the first in Russia he successfully used chloroform for anesthesia in childbirth, conducted various histological studies in the field of obstetrics and gynaecology. A significant part of V.M. Florinsky's publications is devoted to archaeological and ethnographic researches. Discussion: V.M. Florinsky's biography will arise interest in specialists of humanitarian and medical profiles, politicians and public figures. Conclusion: having considered the main periods of life, scientific and state activity of V.M. Florinsky, his significant contribution to the development of obstetrics and gynaecology, anthropology, ethnography, history of medicine and folk medicine and to the formation of eugenics and medical genetics can be noted. V.M. Florinsky as a reformer and administrator in the system of university education strengthened the domestic and international authority of Russian science.

As part of the project on developing methods for removing hydrogen and tritium from the circulation circuits of reactor plants with heavy liquid metal coolants, the authors studied the kinetics of bismuth oxide reduction by hydrogen in the temperature range of 425–500 °C and hydrogen concentrations of 25–100 vol.%. The kinetic characteristics of the test reaction were determined by continuous measurements of the water steam (reaction product) concentration in mixtures of hydrogen with helium that passed through a heated reaction vessel with a sample of bismuth oxide. The water steam concentration was measured by a thermal-conductivity detector. The obtained time dependences of the bismuth oxide reduction degree (with varying reaction conditions) were processed by the affine time transformation method. It was also found that the reduction process ran in kinetic mode. The reduction mechanism is the same in the entire temperature range. The limiting reaction stage is the adsorption of hydrogen on the surface of the bismuth oxide sample. The time dependence of the reduction degree is in good agreement with Avrami-Erofeev equation with n = 1. The reaction activation energy is 92.8 ± 1.9 kJ/mol. The reduction reaction rate is directly proportional to the concentration of hydrogen in its mixture with an inert gas.

Abstract Physical observables cannot depend on the basis one chooses to describe fields. Therefore, all physically relevant properties of a model are, in principle, expressible in terms of basis-invariant combinations of the parameters. However, in many cases it becomes prohibitively difficult to establish key physical features exclusively in terms of basis invariants. Here, we advocate an alternative route in such cases: the formulation of basis-invariant statements in terms of basis-covariant objects. We review several examples where the basis-covariant path is superior to the traditional approach in terms of basis invariants. In particular, this includes the formulation of necessary and sufficient basis-invariant conditions for various physically distinct forms of $$\textit{CP}$$ CP conservation in two- and three-Higgs-doublet models.

This study presents an experimental and numerical investigation on a surface sliding discharge in a supersonic airflow in the presence of an oblique shock wave. In experiments, flow Mach numbers were 1.20–1.68 in the shock tube combined with the discharge chamber. A single high-voltage 25 kV pulse sustains the plasma; the discharge current has a duration of ~500 ns. A surface sliding discharge is developed as a localized channel in a zone of interaction of an oblique shock wave with a boundary layer on the upper wall of the discharge chamber. The discharge channel acts as a linear source of heat and is at the origin of the induced shock wave. The flow field in the discharge chamber is spatio-temporally surveyed using high-speed shadowgraphy imaging with a frequency of up to 525,000 frames per second. The experiments show that the perturbed flow restored the initial structure after more than 100 μs. Numerical simulation with local energy input into the supersonic flow in a flat channel is carried out on the base of unsteady two-dimensional Navier–Stokes equations. It is determined that the dynamics of an induced shock wave are dependent on the energy input regime and on the flow parameters. The thermal energy release in the discharge channel of 0.22–0.29 J was estimated from a comparison of experimental data and numerical simulations.

Coherent extreme ultraviolet (EUV) line emissions can be generated from an atom excited through frustrated tunneling ionization (FTI). The phase variation of the EUV emission in a generation medium along the propagation direction is a critical parameter that determines the phase-matching condition of this new light source. Here we show that the EUV emission sensitively depends on the intensity and phase of a driving laser pulse and the target position. Angle-resolved EUV spectra measured at different target positions and the carrier-envelope phases of the laser pulse exhibit an intensity modulation, showing similar behavior to that of a long-trajectory high harmonic radiation. The four-step model developed for the FTI emission accurately describes the coherent control of the EUV emission. These findings are essential ingredients for developing coherent extreme ultraviolet sources with high photon flux and for utilizing the FTI emission in time-resolved spectroscopy.

Abstract We explore the phenomenology of a unique three-Higgs-doublet model based on the single CP symmetry of order 4 (CP4) without any accidental symmetries. The CP4 symmetry is imposed on the scalar potential and Yukawa interactions, strongly shaping both sectors of the model and leading to a very characteristic phenomenology. The scalar sector is analyzed in detail, and in the Yukawa sector we list all possible CP4-symmetric structures which do not run into immediate conflict with experiment, namely, do not lead to massless or mass-degenerate quarks nor to insufficient mixing or CP -violation in the CKM matrix. We show that the parameter space of the model, although very constrained by CP4, is large enough to comply with the electroweak precision data and the LHC results for the 125 GeV Higgs boson phenomenology, as well as to perfectly reproduce all fermion masses, mixing, and CP violation. Despite the presence of flavor changing neutral currents mediated by heavy Higgs scalars, we find through a parameter space scan many points which accurately reproduce the kaon CP -violating parameter ϵ K as well as oscillation parameters in K and B (s) mesons. Thus, CP4 offers a novel minimalistic framework for building models with very few assumptions, sufficient predictive power, and rich phenomenology yet to be explored.

Lipid transfer proteins (LTPs) participate in many important physiological processes in plants, including adaptation to stressors, e.g., salinity. Here we address the mechanism of this protective action of LTPs by studying the interaction between LTPs and abscisic acid (ABA, a “stress” hormone) and their mutual participation in suberin deposition in root endodermis of salt-stressed pea plants. Using immunohistochemistry we show for the first time NaCl induced accumulation of LTPs and ABA in the cell walls of phloem paralleled by suberin deposition in the endoderm region of pea roots. Unlike LTPs which were found localized around phloem cells, ABA was also present within phloem cells. In addition, ABA treatment resulted in both LTP and ABA accumulation in phloem cells and promoted root suberization. These results suggested the importance of NaCl-induced accumulation of ABA in increasing the abundance of LTPs and of suberin. Using molecular modeling and fluorescence spectroscopy we confirmed the ability of different plant LTPs, including pea Ps-LTP1, to bind ABA. We therefore hypothesize an involvement of plant LTPs in ABA transport (unloading from phloem) as part of the salinity adaptation mechanism.

CP4 3HDM is a unique three-Higgs-doublet model equipped with a higher-order CP-symmetry in the scalar and Yukawa sector. Based on a single assumption (the minimal model with a CP-symmetry of order 4 and no accidental symmetry), it leads to a remarkable correlation between its scalar and Yukawa sectors, which echoes in its phenomenology. A recent scan of the parameter space of CP4 3HDM under the assumption of scalar alignment identified a few dozens of points which passed many flavor constraints. In the present work, however, we show that almost all of these points are now ruled out by the recent LHC searches of t→H+b with subsequent hadronic decays of H+. Apart from a few points with charged Higgses heavier than the top quark, only one point survives all the checks, the model with an exotic, non-2HDM-like generation pattern of H+ couplings with quarks. One can expect many more points with exotic H+ couplings to quarks if the scalar alignment assumption is relaxed.

Several novel bisbenzylisoquinoline alkaloids (BBIQAs) have recently been isolated from a Matis tribe arrow poison and shown by two-electrode voltage-clamp to inhibit mouse muscle nicotinic acetylcholine receptors (nAChR). Here, using radioligand assay with Aplysia californica AChBP and radioiodinated α-bungarotoxin ([125I]-αBgt), we show that BBIQA1, BBIQA2, and d-tubocurarine (d-TC) have similar affinities to nAChR orthosteric site. However, a competition with [125I]-αBgt for binding to the Torpedo californica muscle-type nAChR revealed that BBIQAs1, 2, and 3 are less potent (IC50s = 26.3, 8.75, and 17.0 μM) than d-TC (IC50 = 0.39 μM), while with α7 nAChR in GH4C1 cells, BBIQA1 was less potent that d-TC (IC50s = 162 μM and 7.77 μM, respectively), but BBIQA2 was similar (IC50 = 5.52 μM). In inhibiting the Ca2+ responses induced by acetylcholine in Neuro2a cells expressing the mouse adult α1β1εδ nAChR or human α7 nAChR, BBIQAs1 and 2 had similar potencies to d-TC (IC50s in the range 0.75-3.08 μM). Our data suggest that BBIQA1 and BBIQA2 can inhibit adult muscle α1β1εδ nAChR by both competitive and noncompetitive mechanisms. Further experiments on neuronal α3β2, α4β2, and α9α10 nAChRs, expressed in Xenopus laevis oocytes, showed that similar potencies for BBIQAs1, 2, and d-TC. With α3β2γ2 GABAAR currents were almost completely inhibited by d-TC at a high (100 μM) concentration, but BBIQAs1 and 2 were less potent (only 40-50% inhibition), whereas in competition with Alexa Fluor 546-α-cobratoxin for binding to α1β3γ2 GABAAR in Neuro2a cells, d-TC and these analogs had comparable affinities. Especially interesting effects of BBIQAs1 and 2 in comparison with d-TC were observed for 5-HT3AR: BBIQA1 and BBIQA2 were 5- and 87-fold less potent than d-TC (IC50 = 22.63 nM). Thus, our results reveal that these BBIQAs differ from d-TC in their potencies towards certain Cys-loop receptors, and we suggest that understanding the reasons behind this might be useful for future drug design.

Dioscorea deltoidea is a medicinal plant valued for its high content of steroidal glycosides (SG)—bioactive compounds with cardioprotective and immunomodulation actions, also used to treat reproductive system disorders. To overcome the limitations of natural resources of this species, a suspension cell culture of D. deltoidea was developed as a renewable and ecologically sustainable source of raw biomass and SG. Cell culture demonstrated stable and intensive growth in the laboratory (20 L) and industrial (630 L) bioreactors operated under a semi-continuous regime (specific growth rate 0.11–1.12 day−1, growth index 3.5–3.7). Maximum dry weight accumulation (8.5–8.8 g/L) and SG content (47–57 mg/g DW) were recorded during the stationary phase. Bioreactor-produced cell biomass contained inorganic macro (K, Ca, Mg, Na) and micro (Zn, Mn, Fe, B, Al, Cu, Cr, Se, Co, Ni) elements in concentrations within the safe range of dietary recommendations. Acute toxicity test showed no or insignificant changes in organ weight, hematological panel and blood biochemistry of laboratory animals fed with 2000 and 5000 mg/kg dry biomass. The results suggest that cell culture of D. deltoidea grown in bioreactors has great potential to be used as functional foods and a component of specialized dietary supplements in complex therapy of reproductive system disorders and mineral deficiency.

Convenient and efficient routes to construct hybrid molecules containing diterpene alkaloid lappaconitine and pyrimidine fragments are reported. One route takes place via first converting of lappaconitine to 1-ethynyl-lappaconitine, followed by the Sonogashira cross-coupling-cyclocondensation sequences. The other involves the palladium-catalyzed carbonylative Sonogashira reaction of 5′-iodolappaconitine with aryl acetylene and Mo (CO)6 as the CO source in acetonitrile and subsequent cyclocondensation reaction of the generated alkynone with amidines. The reaction proceeded cleanly in the presence of the PdCl2-(1-Ad)2PBn∙HBr catalytic system. The protocol provides mild reaction conditions, high yields, and high atom and step-economy. Pharmacological screening of lappaconitine-pyrimidine hybrids for antinociceptive activity in vivo revealed that these compounds possessed high activity in experimental pain models, which was dependent on the nature of the substituent in the 2 and 6 positions of the pyrimidine nucleus. Docking studies were undertaken to gain insight into the possible binding mode of these compounds with the voltage-gated sodium channel 1.7. The moderate toxicity of the leading compound 12 (50% lethal dose (LD50) value was more than 600 mg/kg in vivo) and cytotoxicity to cancer cell lines in vitro encouraged the further design of therapeutically relevant analogues based on this novel type of lappaconitine–pyrimidine hybrids.