Optical Control of Antibody Activity by Using Photocleavable Bivalent Peptide–DNA Locks

Antibody-based molecular recognition plays a central role in today's life sciences, ranging from immunoassays to molecular imaging and antibody-based therapeutics. Control over antibody activity by using external triggers such as light could further increase the specificity of antibody-based targeting. Here we present bivalent peptide–DNA ligands containing photocleavable linkers as a noncovalent approach by which to allow photoactivation of antibody activity. Light-triggered cleavage of the 3-amino-3-(2-nitrophenyl)propionic acid peptide linker converted the high-affinity bivalent peptide–DNA lock into weakly binding monovalent ligands, effectively restoring antibody targeting of cell-surface receptors. In this work, a proof of principle was provided with an anti-hemagglutinin antibody, but the molecular design of the lock is generic and applicable to any monoclonal antibody for which an epitope or mimotope of sufficient affinity is available.     

A microfluidic toolbox for cell fusion

Cellular fusion is a key process in many fields ranging from historical gene mapping studies and monoclonal antibody production, through to cell reprogramming. Traditional methodologies for cell fusion rely on the random pairing of different cell types and generally result in low and variable fusion efficiencies. These approaches become particularly limiting where substantial numbers of bespoke one‐to‐one fusions are required, for example, for in‐depth studies of nuclear reprogramming mechanisms. In recent years, microfluidic technologies have proven valuable in creating platforms where the manipulation of single cells is highly efficient, rapid and controllable. These technologies also allow the integration of different experimental steps and characterisation processes into a single platform. Although the application of microfluidic methodologies to cell fusion studies is promising, current technologies that rely on static trapping are limited both in terms of the overall number of fused cells produced and their experimental accessibility. Here we review some of the most exciting breakthroughs in core microfluidic technologies that will allow the creation of integrated platforms for controlled cell fusion at high throughput. © 2015 Society of Chemical Industry     

Mesophase features in isotactic poly(propylene‐co‐1‐heptene) copolymers

The influence of crystallization rate on the interesting polymorphism of random isotactic poly(propylene‐co‐1‐heptene) copolymers was studied, with particular attention to the conditions for obtaining the mesomorphic phase. Owing to the important decrease of cooling rate involved as the 1‐heptene content increases, the mesophase can be clearly observed by DSC for co‐unit contents above about 5 mol%. Furthermore, only the mesophase (or the amorphous phase) was found for the copolymer with 13.9 mol% 1‐heptene at common cooling rates of the calorimeter. Additionally, the copolymer with 21.4 mol% co‐units was found to be completely amorphous under any thermal treatment analyzed. Variable‐temperature diffraction experiments were carried out to ascertain unambiguously the nature of the phases involved. Finally, a remarkable transparency was attained (above 80% transmittance in the visible light region) at intermediate and high 1‐heptene contents, using easily accessible cooling rates. © 2016 Society of Chemical Industry     

Environmental stress cracking of polyvinyl chloride compounds under long-term stress

Polyvinyl chloride compounds rupture prematurely in contact with environmental stress cracking (ESC) agents such as plasticizers. This effect shows a considerable deviation in a stress rupture plot (log stress vs log time) from the expected stress rupture in the absence of ESC agents. PVC and polymers in general dilate under a stress, increase free volume, and allow diffusion of the ESC agent and plasticization of the polymer. However, we show ESC failure is not dependent alone on molecular size of the ESC agent when comparing di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl phthalate (DOP), and tri-2-ethylhexyl trimelitate (TOTM). Therefore this suggests that ESC failure is not strictly associated with diffusion of the ESC agent into the free volume of the PVC, but rather flaws and stress concentrations play a large role. Higher molecular weight PVC retards rupture, both in air and in contact with the ESC agent. However, the safe way to design PVC parts is to avoid ESC contact with stressed PVC rather than using high molecular weight PVC. Part design can play an important role in preventing these premature failures by keeping the ESC agent away from contact with stressed PVC.     

Biological properties of three Mexican isolates of Aujeszky's disease virus

Four strains of Aujeszky's Disease virus (ADV) were included in this study; three Mexican field isolates (215,145 and C-8) in conjunction with the Shope reference strain of ADV, which has known pathogenic characteristics. All four strains were included in each treatment, which consisted of heat treatment, trypsin treatment and passed ten times on chicken embryo fibroblasts. Both virus titer and plaque size were determined on the first and tenth passage and on treated and untreated strains. On each of the treatments, the plaque size had significant differences (p = 0.001) which had relation to the two factors studied, namely strain and passage level. There was no significant variation related to the type of treatment between strains. With the strains under study, the authors also made rabbit pathogenicity tests, and it was found that on passage one, the strains caused clear nervous symptoms and death, while on the tenth passage level, the Mexican strains produced slight pruritus, few nervous symptoms and allowed the rabbits to survive. The mouse test revealed an increased median death time after the treatments, as well as a large increase in standard deviations. These data are interpreted as an increased heterogeneity of the strains in all of the treatments to the strains of viruses.     

On the stability of the one-step exact collocation method for the second kind volterra integral equation with degenerate kernel

The local stability properties of the collocation method applied to a second kind Volterra integral equation with degenerate kernel are investigated. A finite length recurrence relation is derived and theorems for the local stability of the methods are proved.     

Use of ceramic industry milling and glazing waste as an active addition in cement

The beneficial effects of pozzolans on cement manufacture have encouraged their use in that industry. Traditional natural pozzolan have become less available of late, however, due to a decline in quarrying intensity aimed at minimizing the impact on the landscape. At the same time, environmental policies pursue the reduction or elimination of spoil heaps by valorizing industrial waste and by‐products as raw materials, in keeping with the principles of the circular economy. The quest for new types of waste and by‐products with pozzolanic properties has consequently become a priority line of research. This study explored the valorization of one such by‐product, the ceramic sludge resulting from fired clay industry milling and glazing, as a component in new, more eco‐sustainable cements. The sludge was characterized physically, chemically, morphologically, and mineralogically to determine its suitability as a pozzolanic addition in cement. The findings showed that ceramic sludge consists in clustered particles ranging in size from 100 μm to 1 μm. SiO₂, Al₂O₃, and Fe₂O₃ together comprise over 70% of the total composition, while the reactive silica content is greater than the 25% required by the existing legislation. The predominant minerals are quartz, kaolinite, and muscovite, with some zircon. A study of pozzolanic reaction kinetics in the ceramic sludge/lime system revealed that over time this waste can fix lime, generating products such as calcium aluminate hydrates and C–S–H gels. The cements made with ceramic sludge proved to be standard‐compliant in terms of water demand, setting, drying shrinkage and mechanical strength.     

The narrowing-driven approach to functional logic program specialization

Partial evaluation is a semantics-based program optimization technique which has been investigated within different programming paradigms and applied to a wide variety of languages. Recently, a partial evaluation framework for functional logic programs has been proposed. In this framework, narrowing—the standard operational semantics of integrated languages—is used to drive the partial evaluation process. This paper surveys the essentials of narrowing-driven partial evaluation. Elvira Albert, Ph.D.: She is an associate professor in Computer Science at the Technical University of Valencia, Spain. She received her bachelors degree in computer science in 1998 and her Ph.D. in computer science in 2001, both from the Technical University of Valencia. She has investigated on program optimization and on partial evaluation for declarative multi-paradigm programming languages. Her current research interests include term rewriting, multi-paradigm declarative programming, and formal methods, in particular semantics-based program analysis, transformation, specification, verification, and debugging. Germán Vidal, Ph.D.: He is an associate professor in Computer Science at the Technical University of Valencia, Spain. He obtained his bachelors degree in computer science in 1992 and his Ph.D. in computer science in 1996, both from the Technical University of Valencia. He is active on several research topics in Functional Logic Programming. He has worked on compositionality, on abstract interpretation, and on program transformation techniques for functional logic programs. Currently, his research interests include declarative multi-paradigm programming languages, term rewriting, and semantics-based program manipulation, in particular partial evaluation.