SCD – Stem Cell Differentiation Toward Osteoblast Onboard the International Space Station

Microgravity produces a variety of physical, chemical, and biological cues leading to an intricate and largely unresolved network of mechanosensitive molecules, transduction pathways, oxidative stress-related responses, and adaptations. The bone loss observed in astronauts and animal models after spaceflight is attributable to alterations in the bone tissue formation that depends on the continuous remodelling through the activities of bone-resorbing osteoclasts of hematopoietic lineage and bone-forming osteoblast of mesenchymal origin. Focusing on osteogenic differentiation, we present the results of the ”SCD - Stem Cells Differentiation” experiment, aiming to determine how human bone marrow stem cells (hBMSCs) react to a prolonged (approx. 2 weeks) exposure to microgravity in terms of growth, and differentiation when treated with a physiological osteo-inducer as 1,25-dihydroxy vitamin D (Vit D3). The experiment was selected by the European Space Agency and transferred to ISS with the Soyuz-TMA- 16M (ISS 42S). It was carefully prepared because experiments performed on ISS remain a uniquely exceptional means of clarifying the microgravitational effects on osteogenesis, often only partially activated and detectable under simulated conditions. Because of the substantial reduction in calcification observed (about 50% inflight vs. on-ground control), we looked at significantly affected pathways in hBMSCs grown in microgravity vs. on-ground controls. Genome-wide expression changes were assessed via microarray and next generation sequencing (NGS) and integrated with exosomal mi-RNA measurements. Multi-scale pathway analysis of the omics datasets revealed evidence of cell cycle arrest, occurring with a number of osteogenic gene markers, but without indications of adipogenesis, senescence and/or apoptosis.     

The scanning acoustic microscope – a newtool for the materials scientist

Abstract

Scanning acoustic microscopy is a novel method of non-destructive examination enabling images to be formed which show elastic property variations on a microscopic scale. This ability is unique and accounts for the rapid growth of interest in the technique. The instruments can be used for (‘seeing through’, and detecting faults within, samples several millimetres thick. Alternatively, contrast can be obtained from layers only a few micrometres thick, and very narrow (< 100 nm) cracks and discontinuities can be distinguished.

MST/483     

Innovative Work Behaviour: The Impact of Comprehensive HR System Perceptions and the Role of Work–Life Conflict

Human resource (HR) systems have the potential to both foster innovative work behaviour (IWB) and reduce work–life conflict (WLC)—enabling employees to engage in IWB. We investigate the proposed relationships between comprehensive HR systems, WLC and IWB using variance-based structural equation modelling. We found that HR systems that are perceived as comprehensive significantly enhance IWB and decrease feelings of WLC. Contrary to our expectation, we found a significant yet positive effect of WLC on IWB. Employees may respond to WLC constructively by being innovative, improving their environment and making the work–life interface manageable. By promoting IWB, HR systems might also help employees to deal with residual—and, perhaps, unavoidable—levels of WLC.     

Vibration welding of polypropylene-based nanocomposites – The crucial stage for the weld quality

Thermoplastic nanocomposites used for vibration welding are compounded on a twin-screw extruder by dilution of a concentrate masterbatch containing 14 vol% of filler. They are butt welded under different weld pressures by a linear vibration welding machine. By means of a quick ramp-down technology, this machine enables a very short vibration damping time of about 40 ms. The influence of different damping time on the weld strength of various materials is investigated. The experimental results are compared also with the results of simulation. In the case of nano-silica filled polypropylene, no impact of the damping time on the weld quality is detected and the possible reasons for this observation are explained.     

The Change – Point Problem for Angular Data : A Nonparametric Approach

Some directional data collected in a system evaluation of illumination flares are presented. Preliminary analysis suggested a need for procedures to detect, estimate, and test the significance of possible change points in the data. In this article some nonparametric procedures are proposed and applied to the data.     

Coal – Parent of the Industrial Revolution in Great Britain: The early patent history

From approximately 1770 to 1850 Great Britain successfully completed the world's first Industrial Revolution. One of the main reasons for this was the country being endowed with extensive cheap coal supplies which not only provided cheap energy and a lucrative export trade but also acted as a stimulus to innovation in a wide range of industries well before 1770. The author explores these developments through early GB patents.     

Porous HA ceramic for bone replacement: Role of the pores and interconnections – experimental study in the rabbit

Hydroxyapatite (HA) porous ceramics are increasingly used in biomedical applications. Their physical characteristics, such as porous volume, require perfect control of the pore shape, as well as the number and the size of their interconnections.The aim of our study was to evaluate a new HA ceramic using polymethylmethacrylate microbeads (PMMA) as the porous agent. Four interconnection sizes (30, 60, 100 and 130 m) with a 175–260 m pore size and three pore sizes (175–260, 260–350 and 350–435 m) for a 130 m interconnection size were tested. Various HA implants were appraised by microscopic evaluation in a 4.6×10 mm rabbit femur cancellous bone defect 12 weeks after implantation. The best osteoconduction result was obtained in the center of the ceramic by means of a 130 m interconnection size and a 175–260 m mean pore size. Bone formation obtained within the pores was double that obtained in our previous study where naphtalen microbeads were used as the porous agents.© 2001 Kluwer Academic Publishers     

Representative volume elements for discontinuous carbon fibre composites – Part 2: Determining the critical size

This is the second part in a series of papers investigating the size of representative volume elements for discontinuous carbon fibre composites. An ‘embedded cell’ finite element approach, outlined in Part 1, has been used to determine critical RVE sizes for materials with increasing fibre lengths and fibre volume fractions. Convergence of the results for mechanical properties were seen at RVE edge lengths of four times the fibre length (a/L = 4), irrespective of the fibre volume fraction. The calculated Poisson’s ratios (v₁₂ and v₂₁) were largely independent of the RVE size.     

Dynamic and thermodynamic characteristics of the moving-coil linear compressor for the pulse tube cryocooler: Part B – Experimental verifications

Experimental investigations are carried out to verify the theoretical analyses and modeling conducted in Part A. Some empirical corrections are made and two sets of experiments are arranged based on the same compressor coupled with two different coaxial cold fingers typically operating at 80 K and 60 K, respectively. The variations of φ, ΔP, I, θ; the input electric power, η_motor; the cooling capacity and ηCarnot with the operating frequency at the given cooling temperatures are tested and compared with the simulation results, and fairly good agreements are found in both cases. The effects of the cooling temperature on these characteristics are also tested and discussed. Experimental results verify the validity of the theoretical investigations in Part A. The results also indicate that the theoretical studies can apply to wide ranges of both the operating frequency and the cooling temperature.     

Opening the ‘Non-Manufacturing’ envelope: The next big enterprise for international business research

Abstract and Key Results

The use of I–V characteristics for the investigation of selected contacts for spray-deposited CdS:In thin films

An investigation of selected contacts for indium doped cadmium sulphide (CdS:In) thin films was performed through the analysis of the I–V characteristics in the dark and room light at room temperature. Indium, aluminum and silver were selected as contacts where two strips of each metal were vacuum- evaporated on the surface of the film. All of these metals could form ohmic contacts, but indium had shown the best characteristics then aluminum. Films with indium contacts gave the best electrical properties and they are slightly affected by light. Doping and annealing were found to improve the contacts as seen in the I–V plots because they are expected to reduce the contact potential and annealing helps in the formation of an alloy with the semiconductor which forms an ohmic contact.     

The implications of big data for developing and transitional economies: Extending the Triple Helix?

This study examines the implications of the predicted big data revolution in social sciences for the research using the Triple Helix (TH) model of innovation and knowledge creation in the context of developing and transitional economies. While big data research promises to transform the nature of social inquiry and improve the world economy by increasing the productivity and competitiveness of companies and enhancing the functioning of the public sector, it may also potentially lead to a growing divide in research capabilities between developed and developing economies. More specifically, given the uneven access to digital data and scarcity of computational resources and talent, developing countries are at disadvantage when it comes to employing data-driven, computational methods for studying the TH relations between universities, industries and governments. Scientometric analysis of the TH literature conducted in this study reveals a growing disparity between developed and developing countries in their use of innovative computational research methods. As a potential remedy, the extension of the TH model is proposed to include non-market actors as subjects of study as well as potential providers of computational resources, education and training.     

The drunkard’s search: Looking for ‘HRM’ in all the wrong places

Abstract and Key Results

The success-index: an alternative approach to the h-index for evaluating an individual’s research output

Among the most recent bibliometric indicators for normalizing the differences among fields of science in terms of citation behaviour, Kosmulski (J Informetr 5(3):481?C485, 2011) proposed the NSP (number of successful paper) index. According to the authors, NSP deserves much attention for its great simplicity and immediate meaning??equivalent to those of the h-index??while it has the disadvantage of being prone to manipulation and not very efficient in terms of statistical significance. In the first part of the paper, we introduce the success-index, aimed at reducing the NSP-index??s limitations, although requiring more computing effort. Next, we present a detailed analysis of the success-index from the point of view of its operational properties and a comparison with the h-index??s ones. Particularly interesting is the examination of the success-index scale of measurement, which is much richer than the h-index??s. This makes success-index much more versatile for different types of analysis??e.g., (cross-field) comparisons of the scientific output of (1) individual researchers, (2) researchers with different seniority, (3) research institutions of different size, (4) scientific journals, etc.     

An improved multiaxial rainflow algorithm for non-proportional stress or strain histories – Part II: The Modified Wang–Brown method

The objective of this work is to develop a simple multiaxial rainflow algorithm that allows the proper calculation of multiaxial damage in NP histories. Enclosing surface methods are usually employed to obtain the equivalent ranges necessary for damage calculation, as discussed in Part I of this 2-part paper. Part I also presented a new approach to evaluate equivalent ranges in NP histories, called the Moment Of Inertia (MOI) method. This second and last part presents a multiaxial rainflow counting algorithm that allows the MOI and enclosing surface methods to be generalized to non-periodic NP histories and to periodic NP histories formed by complex blocks with multiple cycles each. It is shown that Wang–Brown’s (WB) multiaxial rainflow algorithm has a few idiosyncrasies that can lead to non-conservative predictions, incorrectly filtering out significant events within a multiaxial loading cycle. An improved multiaxial rainflow algorithm is proposed, called Modified Wang–Brown (MWB). It has two main improvements over the WB algorithm. First, the criterion to choose the point where the count is started is modified. Examples are shown to prove that the original criterion can overlook the most damaging event from the history, as opposed to the modified version. And second, the algorithm implementation is significantly simplified when formulated in a reduced five-dimensional Euclidean space. Under plane stress conditions, the algorithm is further simplified using a three-dimensional Euclidean space based on the deviatoric stresses or strains. A simple pseudo-code is presented in a flowchart to efficiently implement the multiaxial count, allowing a fast and efficient calculation of fatigue damage even for very long non-periodic NP histories.     

Information relevant for the design of structure: Ferritic – Heat resistant high chromium steel X10CrAlSi25

In order to determine the behavior of the X10CrAlSi25 steel at room and elevated temperatures, a number of uniaxial tests were performed using a modern computer controlled material testing machine. Based on these tests, two types of their responses were considered. The first type of responses refers to the material properties presented in the form of engineering stress–strain diagrams. From these diagrams it is possible to derive and consequently to determine tensile strength, yield strength and a Modulus of elasticity. The second type of responses refers to creep behavior presented in the form of creep curves. Based on these curves, creep resistance of the considered material can be derived. Besides, the Charpy impact tests were performed with a Charpy impact machine to define Charpy impact energy as the basis for calculating fracture toughness. Considering tensile strength (584 MPa/20 °C) and yield strength (487 MPa/20 °C), it is visible that both of them are decreased when temperature is increased and fairly low strength levels at high temperature (tensile strength: 29 MPa/800 °C; yield strength: 26 MPa/800 °C) are measured. According to performed creep tests it is visible that this material does not belong to the materials resistant to creep.     

The massive production of iron in the Sahelian belt: Archaeological investigations at Korsimoro (Sanmatenga – Burkina Faso)

ABSTRACT

The large smelting site of Korsimoro was investigated during two fieldwork campaigns in 2011 and 2012. Four different technical traditions are identified. Each is characterized by the spatial organization of the working area, the architecture of the furnace, and the assemblages of wastes. Each technical tradition corresponds to one chronological phase. Phase KRS 1 lasted between 600 and 1000 AD and is characterized by small-scale production. Phases KRS 2 and 3, between 1000 and 1450 AD, showed a very significant increase of the production with an important impact on the organization of the society. There is a collapse of the industry at the time of the installation of the Nakomse conquerors followed by a recovery of the production at a small scale during the 17th century.     

Dynamic model for the orbiting scroll based on the pressures in scroll chambers – Part II: Investigations on scroll compressors and model validation

This two-part study proposes a dynamic model for the orbiting scroll based on the pressures in scroll chambers. Part II investigates scroll compressors by using the dynamic model developed in this work to predicate the dynamic characteristics of the scroll compressors and the dynamic model is validated by comparing the predicted results with the experimental results of the powers of two air scroll compressors. This study utilizes two air scroll compressors and ten virtual scroll compressors to investigate the pressure distribution on the wrap surfaces of orbiting scrolls, the component forces and moments of orbiting scrolls, the overturning moment of the scroll mechanism, and the theoretical driving power of scroll compressors. The effects of scroll type (such as modified-wrap scroll, truncated-wrap scroll, single-wrap scroll, multi-wrap scroll, odd-wrap scroll, and even-wrap scroll) on the dynamic performance of the scroll compressor based on the pressures in scroll chambers are also analyzed.