Tin Carboxylate Complexes of Natural Bacteriochlorin for Combined Photodynamic and Chemotherapy of Cancer è

Photodynamic therapy (PDT) is currently one of the most promising methods of cancer treatment. However, this method has some limitations, including a small depth of penetration into biological tissues, the low selectivity of accumulation, and hypoxia of the tumor tissues. These disadvantages can be overcome by combining PDT with other methods of treatment, such as radiation therapy, neutron capture therapy, chemotherapy, etc. In this work, potential drugs were obtained for the first time, the molecules of which contain both photodynamic and chemotherapeutic pharmacophores. A derivative of natural bacteriochlorophyll a with a tin IV complex, which has chemotherapeutic activity, acts as an agent for PDT. This work presents an original method for obtaining agents of combined action, the structure of which is confirmed by various physicochemical methods of analysis. The method of molecular modeling was used to investigate the binding of the proposed drugs to DNA. In vitro biological tests were carried out on several lines of tumor cells: Hela, A549, S37, MCF7, and PC-3. It was shown that the proposed conjugates of binary action for some cell lines had a dark cytotoxicity that was significantly higher (8–10 times) than the corresponding metal complexes of amino acids, which was explained by the targeted chemotherapeutic action of the tin (IV) complex due to chlorin. The greatest increase in efficiency relative to the initial dipropoxy-BPI was found for the conjugate with lysine as a chelator of the tin cation relative to cell lines, with the following results: S-37 increased 3-fold, MCF-7 3-fold, and Hela 2.4-fold. The intracellular distribution of the obtained agents was also studied by confocal microscopy and showed a diffuse granular distribution with predominant accumulation in the near nuclear region.

Quantum gas magnifier for sub-lattice-resolved imaging of 3D quantum systems

Imaging is central to gaining microscopic insight into physical systems, and new microscopy methods have always led to the discovery of new phenomena and a deeper understanding of them. Ultracold atoms in optical lattices provide a quantum simulation platform, featuring a variety of advanced detection tools including direct optical imaging while pinning the atoms in the lattice1,2. However, this approach suffers from the diffraction limit, high optical density and small depth of focus, limiting it to two-dimensional (2D) systems. Here we introduce an imaging approach where matter wave optics magnifies the density distribution before optical imaging, allowing 2D sub-lattice-spacing resolution in three-dimensional (3D) systems. By combining the site-resolved imaging with magnetic resonance techniques for local addressing of individual lattice sites, we demonstrate full accessibility to 2D local information and manipulation in 3D systems. We employ the high-resolution images for precision thermodynamics of Bose–Einstein condensates in optical lattices as well as studies of thermalization dynamics driven by thermal hopping. The sub-lattice resolution is demonstrated via quench dynamics within the lattice sites. The method opens the path for spatially resolved studies of new quantum many-body regimes, including exotic lattice geometries or sub-wavelength lattices3–6, and paves the way for single-atom-resolved imaging of atomic species, where efficient laser cooling or deep optical traps are not available, but which substantially enrich the toolbox of quantum simulation of many-body systems.

Development of an End-Toothed Disc-Based Quick-Change Fixture for Ultra-Precision Diamond Cutting

With its standardized and unified interface, the quick-change fixture is an important part for maintaining high efficiency without compensation of precision in the metal-turning process because it can conveniently realize high-precision repeated clamping and multi-station conversion without complex positioning and adjustment steps. However, the existing quick-change fixture products and related research cannot fully meet the needs of repeatability and applicability raised from ultra-precision, single-point diamond turning with ultra-high accuracy and ultra-small depth of cut. In this paper, we develop a quick-change fixture for ultra-precision diamond turning, in which the end-toothed disc acts as the positioning element. Specifically, the main parameters of two key components of the end-toothed disc and slotted disc spring are calculated analytically to ensure the positioning accuracy of the designed fixture used in the rotation condition, which is further ensured by controlling the machining tolerance of the tooth profile of the end-toothed disc. Additionally, finite element simulations are performed to investigate the static and modal states of the quick-change fixture, which demonstrate a maximum deformation of about 0.9 μm and a minimum natural frequency of 5655.9 Hz for the designed fixture. Two high-precision sensors are used to detect the radial jump and end run-out values after repeated clamping actions, which are employed to verify the repetitive positioning accuracy of the fixture. Subsequent finite-element simulation of the clamping of small-diameter copper bar, as well as the diamond turning experiment, jointly demonstrate that the designed fixture can achieve a precision of 1 μm. Current work provides an effective quick-change fixture to reduce the deformation of a weak-stiffness workpiece caused by clamping deformation in ultra-precision diamond cutting.

Maintenance Techniques for Cracks in Asphalt Layers

Treating cracks in asphalt pavements is a major stage of each maintenance work for engineers. The goal of any crack cure is to limit the water intrusion into underlying pavement structure layers. Such water infiltrates in to base layers of the pavement and may cause damage to the pavement structure. The previous studies focused on crack repairing materials and methods but not the bonding at the interface joint. In this study, the influence of the repairing materials and depth on the bonding at the interface joint using two repairing materials. Slabs were cast to simulate surface of road. Unlikely, slabs contain cracks in the middle of slab with different depths (35 mm, 50 mm, 70 mm). Consequently, these cracks were repaired with two methods; firstly, repairing them with RC+Sand and secondly, with Sika flex®-1a. The slabs were tested after being repaired to know the best method and depth. It has been concluded that slabs having cracks that have been repaired with RC+Sand increase failure load compared with empty cracks and cracks that have been repaired with Sika flex®-1a. Also, cracks with small depth that have been repaired with Sika flex®-1a increase failure load compared with empty cracks.

CALCULATION OF THE CONSTRUCTION OF THE SEWERAGE COLLECTOR DURING ITS REPAIR AND RESTORATION IN AN OPEN WAY

A significant part of sewerage networks in cities in the country are reinforced concrete pipelines with a diameter of 500 to 1500 mm, which lie at a small depth. In many cases, they transport wastewater to treatment plants through areas free of traffic and pedestrians. These factors allow you to effectively perform repair and restoration work in an open way. Corrosion processes that occur in the surface part of the collectors lead to the destruction of the basement. The tray part of the collectors, which is constantly filled with wastewater, remains intact. As studies have shown, the preserved tray part can be successfully used as a fixed formwork and support element in the restoration of the basement of the collector. In this case, to create a new basement part of the collector, in place of the destroyed, it is advisable to use a monolithic structure of polymer concrete reinforced with composite reinforcement. These works are performed using pneumatic and inventory formwork. To implement the proposed structure, it is necessary to perform a preliminary calculation of its load-bearing capacity, provided that it rests on the preserved tray part. As a result of this work it is possible to receive economy in comparison with use for repair and restoration works of polyethylene and fiberglass pipes of necessary diameter. During the calculation, a model of the collector was considered, consisting of a preserved tray part of the collector made of concrete class C12 / 15, the upper part of the collector made of concrete class C20 / 25. The calculation proved the possibility of using polymer concrete structures for repair and restoration of sewers in an open way, provided that the new basement rests on the preserved tray part. The proposed open method allows to significantly reduce the cost of repair and restoration work in comparison with the use of polyethylene and fiberglass pipes.

Intellectualization of the transport system of the Northern sea route

В статье рассмотрены некоторые направления создания и развития интеллектуальной транспортной системы Северного морского пути (СМП). Показано значение СМП в рамках комплексного освоения территории Российской Федерации, приведена его структура. В настоящее время СМП функционирует как внутренний транспортный коридор. Одним из недостатков СМП является небольшая глубина морского канала, что требует проведения соответствующих работ или изменения маршрута. Отмечается влияние изменения погодно-климатических условий в Арктике на транспортную систему СМП. Показаны преимущества использования СМП в качестве международного транзитного транспортного коридора по сравнению с южным маршрутом через Суэцкий канал. Перечислены направления развития Северного морского пути как транспортной системы на основе цифрового усовершенствования инфраструктуры, навигационного, энергетического и информационно-телекоммуникационного обеспечения, а также интеллектуализации производственных процессов на базе беспилотного мультимодального транспорта. Утверждается, что внедрение цифровых технологий на СМП превратит его в один самых высокотехнологичных и эффективных транспортных коридоров в мире. The article considers some directions of creation and development of the intelligent transport system of the Northern Sea Route (NSR). The significance of the NSR in the framework of the integrated development of the territory of the Russian Federation is shown, its structure is given. Currently, the NSR functions as an internal transport corridor. One of the disadvantages of the NSR is the small depth of the sea channel, which will require appropriate work or route changes. The influence of changes in weather and climatic conditions in the Arctic on the transport system of the NSR is noted. The advantages of using the NSR as an international transit transport corridor in comparison with the southern route through the Suez Canal are shown. The directions of the development of the Northern Sea Route as a transport system based on the digital improvement of infrastructure, navigation, energy, information and telecommunications support, as well as the intellectualization of production processes based on unmanned multimodal transport are listed. It is argued that the introduction of digital technologies on the NSR will turn it into one of the most high-tech and efficient transport corridors in the world.

Research on Hydroelastic Response of an FMRC Hexagon Enclosed Platform

The numerical hydroelastic method is used to study the structural response of a hexagon enclosed platform (HEP) of flexible module rigid connector (FMRC) structure that can provide life accommodation, ship berthing and marine supply for ships sailing in the deep ocean. Six trapezoidal floating structures constitute the HEP structure so that it is a symmetrical very large floating structure (VLFS). The HEP has the characteristics of large area and small depth, so its hydroelastic response is significant. Therefore, this paper studies the structural responses of a hexagon enclosed platform of FMRC structure in waves by means of a 3D potential-flow hydroelastic method based on modal superposition. Numerical models, including the hydrodynamic model, wet surface model and finite element method (FEM) model, are established, a rigid connection is simulated by many-point-contraction (MPC) and the number of wave cases is determined. The load and structural response of HEP are obtained and analyzed in all wave cases, and frequency-domain hydroelastic calculation and time-domain hydroelastic calculation are carried out. After obtaining a number of response amplitude operators (RAOs) for stress and time-domain stress histories, the mechanism of the HEP structure is compared and analyzed. This study is used to guide engineering design for enclosed-type ocean platforms.

Synthetic aperture imaging in acoustic microscopy

Acoustic microscopy (AM) provides micro-meter resolution using a highly focused single-element transducer. A drawback in AM is a relatively small depth of field, resulting in poor resolution outside the focus. Synthetic aperature focusing technique (SAFT) can be used to improve the image resolution throughout the field of view. SAFT mathematically synthesizes the effect of an array transducer and produces dynamic focusing and depth-independent resolution. SAFT in time domain with and without apodization, TD-SAFT and ATD-SAFT, respectively, and in frequency domain (FD-SAFT) were implemented and tested using simulated and experimental radio-frequency data from an acoustic microscope at 400 MHz. Lateral resolution of all the SAFT reconstructed images were better than those of the conventional B-mode images. While TD-SAFT and FD-SAFT permformed better than ATD-SAFT in improving the lateral resolution, ATD-SAFT provided lower side lobes. In conclusion, SAFT improves resolution in AM outside the focal region.

Synthetic aperture imaging in acoustic microscopy

Acoustic microscopy (AM) provides micro-meter resolution using a highly focused single-element transducer. A drawback in AM is a relatively small depth of field, resulting in poor resolution outside the focus. Synthetic aperature focusing technique (SAFT) can be used to improve the image resolution throughout the field of view. SAFT mathematically synthesizes the effect of an array transducer and produces dynamic focusing and depth-independent resolution. SAFT in time domain with and without apodization, TD-SAFT and ATD-SAFT, respectively, and in frequency domain (FD-SAFT) were implemented and tested using simulated and experimental radio-frequency data from an acoustic microscope at 400 MHz. Lateral resolution of all the SAFT reconstructed images were better than those of the conventional B-mode images. While TD-SAFT and FD-SAFT permformed better than ATD-SAFT in improving the lateral resolution, ATD-SAFT provided lower side lobes. In conclusion, SAFT improves resolution in AM outside the focal region.