The Rise of Retinal Organoids for Vision Research

Retinal degenerative diseases lead to irreversible blindness. Decades of research into the cellular and molecular mechanisms of retinal diseases, using either animal models or human cell-derived 2D systems, facilitated the development of several therapeutic interventions. Recently, human stem cell-derived 3D retinal organoids have been developed. These self-organizing 3D organ systems have shown to recapitulate the in vivo human retinogenesis resulting in morphological and functionally similar retinal cell types in vitro. In less than a decade, retinal organoids have assisted in modeling several retinal diseases that were rather difficult to mimic in rodent models. Retinal organoids are also considered as a photoreceptor source for cell transplantation therapies to counteract blindness. Here, we highlight the development and field’s improvements of retinal organoids and discuss their application aspects as human disease models, pharmaceutical testbeds, and cell sources for transplantations.     

Ice Crystal Growth in Sucrose Solutions Containing Kappa- and Iota-Carrageenans

Measurements of ice recrystallization inhibition (IRI) and thermal hysteresis (TH) activities of kappa (κ)- and iota (ι)-carrageenans were carried out to examine whether they can be novel cryoprotectants or not. IRI measurements indicate that both carrageenans reduce recrystallization in sucrose solution, but that the IRI activity of κ-carregeenan is higher than that of ι-carrageenan. TH measurements indicate that κ- and ι-carrageenans do not exhibit TH activity. TH activity measurements of antifreeze glycoprotein (AFGP) in the presence of κ-carregeenan demonstrate that this carregeenan neither influences the TH activity of AFGP nor the shape of the ice crystals. The round ice crystal shape transformed into an angular and elongated shape in the presence of both carregeenans.     

Looking out to look in: inspiration from social sciences for construction management research

In reaction to the recent call for critical debate in the field of construction management research, I argue that we should embrace the richness of adjacent fields of study in order to dynamically develop our own and face the plethora of contemporary societal challenges that exist in our industry. I introduce the concepts of other-than-rational thinking in decision-making and multiplicity in management responses as examples of inspirational sources from social sciences that would contribute to truly understanding the driving forces of construction management processes. I connect these concepts to contemporary studies in construction management and share my experiences with several positive collaborative approaches in conducting construction management research.     

Taking on a wider view: public value interests of construction clients in a changing construction industry

For financial and strategic reasons, public and semi-public construction clients increasingly depend on private parties to carry out public service delivery. They subcontract operational responsibilities to private parties while remaining socio-politically responsible for ensuring public values. Public administration literature mainly addresses the importance of procedural and performance values in safeguarding public values. However, safeguarding the quality of the built environment also requires a focus on product values. In this study, we aim to increase the understanding of the meaning and significance of public values in the daily practice of public construction clients and identify the challenges they face in commissioning these seemingly opposing values. A set of semi-structured interviews with the public administrators of a variety of public and semi-public construction client organizations in the Netherlands shows that both internal and external factors influence the collaborative practices between clients and contractors. This causes a value shift from an emphasis on procedural values to managing performance and product values, indicating that clients need to take on a wider view on public values. Six main public value dilemmas were found that complicate the task of developing an open, transparent and sustainable long-term client–contractor relationship. The current contractual system, however, lacks the flexibility to facilitate this product-based value view in construction.     

Burn Rate Models for Gun Propellants

In the past, Vieille's law and minor modifications of it described sufficiently the linear burning rate of gun propellants which governs the design of charges by interior ballistic simulations. Recent developments to increase the performance led to new gun concepts and innovative propellants. These are the electrothermal‐chemical gun, porous and foamed charges as well as formulations exhibiting a temperature independent burning. Vieille's law cannot fully meet experimental results in these cases. Approaches based on the heat flow equation in the solid energetic material give simplified formulas to extend the validity. These burning rate models have the ability to describe the experimentally determined burning behavior at least in a simplified or qualitative way. More sophisticated methods consider complex geometrical structures in the solid or take into account the actual progress in phase behavior and reaction kinetics of heterogeneous combustion. The dependence of the burning rate on initial temperature, on phase transitions, porous structure and gaseous reactions can be described.     

连续相黏度对膜乳化结果的影响

Oil-in-water(o/w) emulsions were produced with a membrane emulsification system. The effect of the continuous phase viscosity on the emulsification was studied. The theoretical analyses show that the continuous phase viscosity influences not only the flow field of the continuous phase but also the interfacial tension. The droplet size distribution and disperse phase flux for different continuous phase viscosity were investigated experimentally at constant wall shear stress and constant volume flow rate of the continuous phase respectively.     

High‐Temperature Neutron Diffraction,Raman Spectroscopy,and First‐Principles Calculations of Ti3SnC2 and Ti2SnC

Herein, we report—for the first time—on the additive‐free bulk synthesis of Ti₃SnC₂. A detailed experimental study of the structure of the latter together with a secondary phase, Ti₂SnC, is presented through the use of X‐ray diffraction (XRD), and high‐resolution transmission microscopy (HRTEM). A previous sample of Ti₃SnC₂, made using Fe as an additive and Ti₂SnC as a secondary phase, was studied by high‐temperature neutron diffraction (HTND) and XRD. The room‐temperature crystallographic parameters of the two MAX phases in the two samples are quite similar. Based on Rietveld analysis of the HTND data, the average linear thermal expansion coefficients of Ti₃SnC₂ in the a and c directions were found to be 8.5 (2)·10^?6 K^?1 and 8.9 (1)·10^?6 K^?1, respectively. The respective values for the Ti₂SnC phase are 10.1 (3)·10^?6 K^?1 and 10.8 (6)·10^?6 K^?1. Unlike other MAX phases, the atomic displacement parameters of the Sn atoms in Ti₃SnC₂ are comparable to those of the Ti and C atoms. When the predictions of the atomic displacement parameters obtained from density functional theory are compared to the experimental results, good quantitative agreement is found for the Sn atoms. In the case of the Ti and C atoms, the agreement is more qualitative. We also used first principles to calculate the elastic properties of both Ti₂SnC and Ti₃SnC₂ and their Raman active modes. The latter are compared to experiment and the agreement was found to be good.     

State of the Art Treatment of Non-Ferrous Castings 3-in-1 Heat Treatment Systems Combine Foundry Processes

The interior of a high-pressure die-casting is of an unsatisfactory quality. Engine blocks made with this die casting process show lower specific engine performance. Pressure die-casting can hardly be heat treated for obvious reasons PSM (Precision Sand Molds) process uses sand and organic binder to generate a mold and even allows the manufacturing of complex diesel engine blocks in aluminum alloys. Combined technologies are available for semi-permanent mold castings with cores and castings made in Precision Sand Molds with organic binders. Castings are placed into the special heat treatment furnace immediately after pouting without the operations in stand alone machinery. This patented Sand Lion^R 3-in-1 technology processes hot castings and carries out three (3) foundry processes simultaneously in one (1) automated machine: 1) De-coring and sand removal; 2) Thermal sand reclamation; 3) Solution heat treatment of castings. The combination of several main casting processes is reflected in significant reductions of energy consumption, of production costs, and improving the quality of the castings. Audits in foundries using the 3-in-1 process showed an average reduction in production costs of more than 30%.     

Kinetic study of hydrogen peroxide decomposition at high temperatures and concentrations in two capillary microreactors

On the background of the direct adipic acid synthesis from cyclohexene and H₂O₂, a kinetic model was derived for the H₂O₂ decomposition catalyzed by sodium tungstate at high H₂O₂ concentrations and high temperatures. A perfluoroalkoxy (PFA) and a stainless steel micro‐flow capillary match commonly used microreactor materials. In the PFA capillary, the decomposition of hydrogen peroxide increased with residence time, reaction temperature and catalyst loading. The reaction order with respect to hydrogen peroxide and sodium tungstate was zero and one, respectively. Simulated data fit well with experimental data in the PFA capillary. While showing a similar trend as that in the PFA capillary, the stainless steel capillary exhibited much higher reaction rates. The steel surface participated in the decomposition process as a heterogeneous catalyst. Key influencing factors of the H₂O₂ decomposition provided some clues on the reaction mechanism of the adipic acid synthesis and its process optimization. © 2016 American Institute of Chemical Engineers AIChE J, 63: 689–697, 2017