Structural basis of Nrd1–Nab3 heterodimerization

Heterodimerization of RNA binding proteins Nrd1 and Nab3 is essential to communicate the RNA recognition in the nascent transcript with the Nrd1 recognition of the Ser5-phosphorylated Rbp1 C-terminal domain in RNA polymerase II. The structure of a Nrd1–Nab3 chimera reveals the basis of heterodimerization, filling a missing gap in knowledge of this system. The free form of the Nrd1 interaction domain of Nab3 (NRID) forms a multi-state three-helix bundle that is clamped in a single conformation upon complex formation with the Nab3 interaction domain of Nrd1 (NAID). The latter domain forms two long helices that wrap around NRID, resulting in an extensive protein–protein interface that would explain the highly favorable free energy of heterodimerization. Mutagenesis of some conserved hydrophobic residues involved in the heterodimerization leads to temperature-sensitive phenotypes, revealing the importance of this interaction in yeast cell fitness. The Nrd1–Nab3 structure resembles the previously reported Rna14/Rna15 heterodimer structure, which is part of the poly(A)-dependent termination pathway, suggesting that both machineries use similar structural solutions despite they share little sequence homology and are potentially evolutionary divergent.

STRUCTURAL SOLUTIONS FOR STRENGTHENING DAMAGED STONE ARCH STRUCTURES

Рассмотрены исторические аспекты возникновения каменных арочных конструкций перекрытий, материалы, которые использовались для их возведения в различные исторические периоды, классификация арочных конструкций, а также основные конструктивные решения и технологические аспекты их возведения. Приведены результаты работ, выполненных по определению численных значений геометрических параметров и обследованию технического состояния арочных конструкций зданий старой постройки, расположенных в центральной (исторической) части г. Казани. Приведены результаты исследования работ других авторов по определению наиболее часто встречающихся дефектов и повреждений в арках, а также причины их возникновения. Рассмотрены технические решения различных авторов по усилению арочных конструкций, с использованием различных материалов, в том числе и композитными материалами на основе однонаправленных углеродных волокон. Описана область применения и изложены технические решения, разработанные авторами статьи для усиления арочных конструкций, которые учитывают особенности их конструктивных решений и повреждений. We considered the historical aspects of the emergence of stone arched structures of ceilings, the materials used for their construction in various historical periods, the classification of arched structures, as well as the main design solutions and technological aspects of their construction. We present the results of the work performed to determine the numerical values of geometric parameters and to survey the technical condition of arched structures of old buildings located in the central (historical) part of Kazan. As well we demonstrate the results of a study of the works of other authors to determine the most common defects and damages in arches and the causes of their occurrence. We show the technical solutions of various authors to strengthen arched structures using various materials, including composite materials based on unidirectional carbon fibers. We describe the scope of application and outline the technical solutions developed by the authors of the article for strengthening arched structures that take into account the features of their design solutions and damages.

Accounting for horizontal torsional vibrations of foundations when calculating seismic load

The article presents a method for calculating in-plane vibrations of building structures under seismic load taking into account the possibility of foundation displacement, which is similar to horizontal torsional vibrations when calculating earthquake forces. The method is illustrated by the structural design of a seven-storey tower-like building with a massive foundation. We develop transfer functions for a massive rigid body, which are subsequently used for calculating the response of the foundation subject to base shears and moments applied to the outer plane of the foundation under seismic forces. The structural calculations conducted for ductile structures with the first frequency of ~2.4 Hz and for more rigid structures with the first frequency of 7.1 Hz showed that, depending on the building stiffness, reduced seismic forces increase by 1.5–2 times. According to the results obtained, when designing structures in areas of high seismic hazard, account should be taken of possible foundation flexibility effects depending on different types of soil and structural solutions of particular buildings.

Development of Transport for Disabled People on the Example of Wheelchair Propulsion with Cam-Thread Drive

The increasingly frequent use of electric drives is a new direction of development in personal transport. Sometimes these drives take over the work of human muscles, and sometimes they only support them. This is particularly evident in means of transport such as bicycles and scooters, but also in transporting people with disabilities. This study questions whether this is the only right development direction, and explores the possibility of developing means of transport for the more effective use of human muscles by proposing new structural solutions. We identified that such an action favors the minimization of the environmental load generated by technical facilities and, at the same time, may be a response to social needs resulting from the principles of sustainable development. This paper presents the operation principle of the innovative Wheelchair Cam-thread Drive (WCD), followed by field tests, laboratory measurements and biomechanical analyses of the WCD, comparing it with a typical Wheelchair Push-rim Drive (WPD). We found that the WCD allows efficient driving on flat and level surfaces, but its propulsion method can adversely alter the location of the center of gravity on the human-wheelchair system. A brake is also required to control the driving speed. Ultimately, the WCD was found to put less strain on the human movement system, so it could be used for rehabilitation exercises. The WCD appears to be a promising design, deserving further research into the drive biomechanics and the optimization of the mechanism operation. Such an innovative manual drive presents an interesting alternative to electric drives.

Parametric modeling compressed ellipsoid of rotation as the analytic surface

The article deals with the shaping of the analytical surface in the form of a compressed ellipsoid of rotation. In the process of research, the principle of the golden section was applied, an ellipsoid of rotation with optimal parameters for the design of a large-span unique building of the exhibition complex was obtained. To solve the problem of choosing a rational analytical surface in the Lira-CAD software package, three variants of constructive solutions for the frame of the exhibition complex have been developed. The finite element method is used, the most popular numerical calculation method for studying the stress-strain state of large-span buildings and structures. The analysis of the calculation results made it possible to choose the optimal variant of the structural solutions of the building frame. The check of the dynamic characteristics of the proposed structural solution of the building frame is carried out. The obtained results of the dynamic calculation showed the correctness and efficiency of the adopted structural solutions of the building frame.

The Function and Potential of Innovative Reinforced Concrete Prefabrication Technologies in Achieving Residential Construction Goals in Germany and Poland

This paper presents the role and potential of housing built using innovative reinforced concrete prefabrication technologies. The subject was presented by investigating the share of such buildings in the achievement of housing goals in Germany and Poland, where they currently constitute one of the most dynamically developing housing sector branches. The phenomenon has been presented via comparative analyses of selected designs by manufacturers from the sector and development companies. Prefabrication is essentially based on optimising architectural and structural solutions and leads to lowering financial and material cost; decreasing project completion time. At present, these goals are achieved by systematising the design and construction process and using the potential offered by building information modelling technology (BIM). This enables coordination between design specialisations and reduces the number of errors, increasing manufacturing and assembly efficiency. Innovative prefabricated technologies are solutions that are either new or are considerably improved in terms of technical specifications, components and materials, that use the latest software, are easy to assemble, durable, energy efficient, can be disassembled and reused and have a low carbon footprint and can be considered aesthetically pleasing. Contemporary prefabricated housing architecture is a combination of innovative technological solutions that enables constructing sustainable architecture and emphasizes the aesthetic features of structural solutions and solutions.

“My 9 to 5 Job Is Birth Work”: A Case Study of Two Compensation Approaches for Community Doula Care

With the increased policy emphasis on promoting doula care to advance birth equity in the United States, there is a vital need to identify sustainable and equitable approaches for compensation of community doulas, who serve clients experiencing the greatest barriers to optimal pregnancy-related outcomes. This case study explores two different approaches for compensating doulas (contractor versus hourly employment with benefits) utilized by SisterWeb San Francisco Community Doula Network in San Francisco, California. We conducted qualitative interviews with SisterWeb doulas in 2020 and 2021 and organizational leaders in 2020. Overall, leaders and doulas reported that the contractor approach, in which doulas were paid a flat fee per client, did not adequately compensate doulas, who regularly attend trainings and provide additional support for their clients (e.g., referrals to promote housing and food security). Additionally, this approach did not provide doulas with healthcare benefits, which was especially concerning during the COVID-19 pandemic. As hourly, benefited employees, doulas experienced a greater sense of financial security and wellbeing from receiving consistent pay, compensation for all time worked, and benefits such as health insurance and sick leave, allowing some to dedicate themselves to birth work. Our study suggests that efforts to promote community doula care must integrate structural solutions to provide appropriate compensation and benefits to doulas, simultaneously advancing birth equity and equitable labor conditions for community doulas.

Saving the Freedom of Information Act

Enacted in 1966, The Freedom of Information Act (or FOIA) was designed to promote oversight of governmental activities, under the notion that most users would be journalists. Today, however, FOIA is largely used for purposes other than fostering democratic accountability. Instead, most requesters are either individuals seeking their own files, businesses using FOIA as part of commercial enterprises, or others with idiosyncratic purposes like political opposition research. In this sweeping, empirical study, Margaret Kwoka documents how agencies have responded to the large volume of non-oversight requesters by creating new processes, systems, and specialists, which in turn has had a deleterious impact on journalists and the media. To address this problem, Kwoka proposes a series of structural solutions aimed at shrinking FOIA to re-center its oversight purposes.