Profiles of inflated surfaces

We study the shape of inflated surfaces introduced in \cite{B1} and \cite{P1}. More precisely, we analyze profiles of surfaces obtained by inflating a convex polyhedron, or more generally an almost everywhere flat surface, with a symmetry plane. We show that such profiles are in a one-parameter family of curves which we describe explicitly as the solutions of a certain differential equation.Comment: 13 pages, 2 figure

Cooperative multivalent receptor binding promotes exposure of the SARS-CoV-2 fusion machinery core

The molecular events that permit the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to bind, fuse, and enter cells are important to understand for both fundamental and therapeutic reasons. Spike proteins consist of S1 and S2 domains, which recognize angiotensin-converting enzyme 2 (ACE2) receptors and contain the viral fusion machinery, respectively. Ostensibly, the binding of spike trimers to ACE2 receptors promotes the preparation of the fusion machinery by dissociation of the S1 domains. We report the development of bottom-up coarse-grained (CG) models validated with cryo-electron tomography (cryo-ET) data, and the use of CG molecular dynamics simulations to investigate the dynamical mechanisms involved in viral binding and exposure of the S2 trimeric core. We show that spike trimers cooperatively bind to multiple ACE2 dimers at virion-cell interfaces. The multivalent interaction cyclically and processively induces S1 dissociation, thereby exposing the S2 core containing the fusion machinery. Our simulations thus reveal an important concerted interaction between spike trimers and ACE2 dimers that primes the virus for membrane fusion and entry

Lorentz gauge theory as a model of emergent gravity

We consider a class of Lorentz gauge gravity theories within Riemann-Cartan geometry which admits a topological phase in the gravitational sector. The dynamic content of such theories is determined only by the contortion part of the Lorentz gauge connection. We demonstrate that there is a unique Lagrangian that admits propagating spin one mode in correspondence with gauge theories of other fundamental interactions. Remarkably, despite the R^2 type of the Lagrangian and non-compact structure of the Lorentz gauge group, the model possesses rather a positive-definite Hamiltonian. This has been proved in the lowest order of perturbation theory. This implies further consistent quantization and leads to renormalizable quantum theory. It is assumed that the proposed model describes possible mechanism of emergent Einstein gravity at very early stages of the Universe due to quantum dynamics of contortion.Comment: 11 pages, final version, minor correction

Protracted fever after infliximab induction therapy in a patient with ulcerative colitis (clinical case)

Inflammatory bowel diseases (ulcerative colitis and Crohn’s disease) tend to increase in frequency and prevalence worldwide and lead to a significant reduction in quality of life with a complicated course. Intravenous administration of corticosteroids in acute severe ulcerative colitis is effective in 60–70 % of cases. Rescue therapy for patients with steroid‐refractory and steroid-dependence attacks is effective for reducing colectomy or colproctectomy and improves long-term treatment outcomes. Despite the proven efficacy of infliximab, limitations to the use of monoclonal antibodies are adverse reactions to the administration of genetically engineered biologic therapy (GEBT), both well-known and studied, and rare.The aim of the study. To analyze a case of an extremely rare and paradoxical incurable hyperergic reaction that occurred after using genetically engineered biological therapy with tumor necrosis factor alpha blockers in a patient suffering from ulcerative colitis.Materials and methods. We carried out the search in the PubMed, Embase, Scopus and Medline databases until November 1, 2022 using the following keywords: inflammatory bowel disease, ulcerative colitis (UC), anti-tumor necrosis factor α (antiTNFα), infliximab, fever, adverse events. In the scientific electronic library eLIBRARY, a search was made for Russian-language publications using similar queries in Russian. We analyzed the patient’s medical records from 03.06.2013 up to the present day; the patient signed an informed consent for the publication and discussion of the presented data.Conclusion. The widespread use of GEBT in the treatment of autoimmune and autoinflammatory diseases leads to the accumulation of both positive and negative experience of clinicians in real clinical practice. The officially described adverse events in the appointment of any drug suggest options for their prevention and treatment. Atypical manifestations or casuistic cases must be systematized for further fundamental pathophysiological studies

Influence of anionic surfactant on stability of nanoparticles in aqueous solutions

Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe and effective application of nanoparticles, for instance, in the oil industry. As conventional oil reserves are depleted, it is necessary to advance chemical enhanced oil recovery (cEOR) techniques to develop unconventional oil reservoirs. Nanoparticles modified by surfactants can be a promising reagent in cEOR. These nanomaterials can reduce interfacial tension and change the wettability of reservoir rock, which leads to an increase in oil recovery. However, the application of nanoparticles is limited by their substantial aggregation in aqueous solutions. The purpose of this work is to select nanoparticles for obtaining stable sols in water in the presence of an anionic surfactant and to optimize the conditions (pH) for further modifying the nanoparticles with the anionic surfactant. Sodium dodecyl sulfate (SDS) is used as an anionic surfactant. The aggregation of oxide and carbon nanoparticles in water and anionic surfactant solutions was studied by laser diffraction, dynamic and electrophoretic light scattering methods. Most of the studied nanoparticles in water form aggregates with bi-, three- and polymodal particle size distributions. TiO2 nanoparticles obtained by plasma dynamic synthesis form the most stable sols in anionic surfactant solutions. The range of 5–7 pH is defined as optimal for their modification with surfactants. The stability of carbon nanoparticles in aqueous solutions increases significantly in the presence of a surfactant. The obtained results form the basis for further research on the modification of marked nanoparticles in surfactant solutions

WET SCRUBBER COLUMN FOR AIR DETRITIATION

This paper evaluates detritiation of air contaminated with tritium in the for

Predicting death in patients with end-stage liver disease: a new model for assessing disease severity

Objective. To define possibilities of clinical application of the new original method for estimating failure (death) probability in patients on a liver transplant waiting list.Material and Methods. The study included 350 patients who had been on a liver transplant waiting list for 5 years. Using the comparison of Mann-Whitney test results and evaluation of sensitivity and specificity (ROC curves) it was established that values of age, MELD-Na score, leukocyte level, nature of liver failure and presence of portal vein thrombosis had statistically significant differences between the dead and survived patients (p < 0.05). By means of binary logistic regression, the model assessing the risk of death taking into consideration indicators mentioned above has been obtained. The new index of death probability of a patient on a liver transplant waiting list within one year has been created.Results. Quality evaluation of the created model and the index derived from it showed that the new index had a stronger ability to estimate somatic status severity in a patient with cirrhosis and allowed to make more precise prognosis of adverse outcome risk for not less than 12 months as compared to the standard MELD-Na score. The predicted risk of death coincided with actual mortality of patients in 83% of cases. The EPV criterion was 17.4 what exceeded the minimum admissible threshold of the criterion (10) for small samples and allowed to use the obtained index.Conclusion. The original method allows increasing the accuracy of assessment of failure (death) development in a patient with cirrhosis for one year at any time of its application in the non-invasive way, using the data of the examination standard. In addition, the method helps setting priority in liver transplantation

Spin physics with antiprotons

New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to cross-sections in which the parton distribution functions (PDF) only appear, without any contribution from fragmentation functions; such processes are not affected by the chiral suppression of the transversity function $h_1(x)$. Spin asymmetries in hyperon production and Single Spin Asymmetries are discussed as well, together with further items like electric and magnetic nucleonic form factors and open charm production. Counting rates estimations are provided for each physical case. The sketch of a possible experimental apparatus is proposed.Comment: Presented for the proceedings of ASI "Spin and Symmetry", Prague, July 5-10, 2004, to be published in Czech. J. Phys. 55 (2005

Оригинальная методика трансплантации поджелудочной железы в аспекте профилактики интраабдоминальных гнойных осложнений

A clinical case of pancreas transplantation (PTx) based on an original technique is presented. The applied technique made it possible to prevent the spread and involvement of the abdominal organs in an inflammatory process caused by postoperative graft pancreatitis, and to preserve the pancreas graft.Представлено клиническое наблюдение трансплантации поджелудочной железы по оригинальной методике. Примененная методика позволила предупредить распространение и вовлечение органов брюшной полости в воспалительный процесс, обусловленный послеоперационным панкреатитом трансплантата, и сохранить трансплантат поджелудочной железы