Light‐Driven Proton Transfer for Cyclic and Temporal Switching of Enzymatic Nanoreactors

Temporal activation of biological processes by visible light and subsequent return to an inactive state in the absence of light is an essential characteristic of photoreceptor cells. Inspired by these phenomena, light‐responsive materials are very attractive due to the high spatiotemporal control of light irradiation, with light being able to precisely orchestrate processes repeatedly over many cycles. Herein, it is reported that light‐driven proton transfer triggered by a merocyanine‐based photoacid can be used to modulate the permeability of pH‐responsive polymersomes through cyclic, temporally controlled protonation and deprotonation of the polymersome membrane. The membranes can undergo repeated light‐driven swelling–contraction cycles without losing functional effectiveness. When applied to enzyme loaded‐nanoreactors, this membrane responsiveness is used for the reversible control of enzymatic reactions. This combination of the merocyanine‐based photoacid and pH‐switchable nanoreactors results in rapidly responding and versatile supramolecular systems successfully used to switch enzymatic reactions ON and OFF on demand.     

Highly Tunable Thiol-Ene Photoresins for Volumetric Additive Manufacturing

Volumetric additive manufacturing (VAM) forms complete 3D objects in a single photocuring operation without layering defects, enabling 3D printed polymer parts with mechanical properties similar to their bulk material counterparts. This study presents the first report of VAM-printed thiol-ene resins. With well-ordered molecular networks, thiol-ene chemistry accesses polymer materials with a wide range of mechanical properties, moving VAM beyond the limitations of commonly used acrylate formulations. Since free-radical thiol-ene polymerization is not inhibited by oxygen, the nonlinear threshold response required in VAM is introduced by incorporating 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a radical scavenger. Tuning of the reaction kinetics is accomplished by balancing inhibitor and initiator content. Coupling this with quantitative measurements of the absorbed volumetric optical dose allows control of polymer conversion and gelation during printing. Importantly, this work thereby establishes the first comprehensive framework for spatial–temporal control over volumetric energy distribution, demonstrating structures 3D printed in thiol-ene resin by means of tomographic volumetric VAM. Mechanical characterization of this thiol-ene system, with varied ratios of isocyanurate and triethylene glycol monomers, reveals highly tunable mechanical response far more versatile than identical acrylate-based resins. This broadens the range of materials and properties available for VAM, taking another step toward high-performance printed polymers.     

Flexible data anonymization using ARX—Current status and challenges ahead

The race for innovation has turned into a race for data. Rapid developments of new technologies, especially in the field of artificial intelligence, are accompanied by new ways of accessing, integrating, and analyzing sensitive personal data. Examples include financial transactions, social network activities, location traces, and medical records. As a consequence, adequate and careful privacy management has become a significant challenge. New data protection regulations, for example in the EU and China, are direct responses to these developments. Data anonymization is an important building block of data protection concepts, as it allows to reduce privacy risks by altering data. The development of anonymization tools involves significant challenges, however. For instance, the effectiveness of different anonymization techniques depends on context, and thus tools need to support a large set of methods to ensure that the usefulness of data is not overly affected by risk-reducing transformations. In spite of these requirements, existing solutions typically only support a small set of methods. In this work, we describe how we have extended an open source data anonymization tool to support almost arbitrary combinations of a wide range of techniques in a scalable manner. We then review the spectrum of methods supported and discuss their compatibility within the novel framework. The results of an extensive experimental comparison show that our approach outperforms related solutions in terms of scalability and output data quality—while supporting a much broader range of techniques. Finally, we discuss practical experiences with ARX and present remaining issues and challenges ahead.     

The ultrastructure of spruce kraft pulps studied by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS)

Surface properties of spruce (Picea abies) kraft pulps cooked for different times and further OD₀E₁D₁E₂D₂-bleached were investigated with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). A rough correlation between the increasing relative amount of the fibrillar surface structure in AFM images and increasing O/C atomic ratio in XPS-spectra was found with proceeding delignification. At the end of cooking (120 min) only about 1/3 of the fibre surface consisted of cellulose. The detailed analysis of the relative peak areas of the different C1s components in the XPS-spectra indicated that the granules at the beginning of cooking at 170 °C consisted mainly of lignin and extractives. The analysis also showed that different steps of the bleaching sequence were quite specific in removing structural components. Furthermore, the lignin removal was shown not to result automatically in increased fraction of exposed cellulose surface, but could also lead in increased relative amount of surface extractives. Evidence for the high surface content of hemicelluloses for the D2-stage sample was observed. Hemicelluloses with both fibrillar and amorphous morphology were found to be present.     

The Relationship Between Online Pornography and the Sexual Objectification of Women: The Attenuating Role of Porn Literacy Education

Media literacy interventions partly aim at preventing undesirable media effects at a later point of time. However, longitudinal research on the interaction between media literacy education and media effects is lacking. In this longitudinal study among 1,947 13–25-year-olds, we started to address this lacuna by examining the potential of porn literacy education at schools to attenuate the longitudinal relationship between exposure to sexually explicit Internet material (SEIM) and views of women as sex objects. A two-way interaction effect emerged: The relationship between SEIM and sexist views became weaker, the more users had learned from porn literacy education. No gender or age differences occurred. This study thus provides some first evidence for the role of media education in reducing undesirable media effects.     

Enantioselective Reduction of Citral Isomers in NCR Ene Reductase: Analysis of an Active‐Site Mutant Library

A deeper understanding of the >99 % S‐selective reduction of both isomers of citral catalyzed by NCR ene reductase was achieved by active‐site mutational studies and docking simulation. Though structurally similar, the E/Z isomers of citral showed a significantly varying selectivity response to introduced mutations. Although it was possible to invert (E)‐citral reduction enantioselectivity to ee 46 % (R) by introducing mutation W66A, for (Z)‐citral it remained ≥88 % (S) for all single‐residue variants. Residue 66 seems to act as a lever for opposite binding modes. This was underlined by a W66A‐based double‐mutant library that enhanced the (E)‐citral derived enantioselectivity to 63 % (R) and significantly lowered the S selectivity for (Z)‐citral to 44 % (S). Formation of (R)‐citronellal from an (E/Z)‐citral mixture is a desire in industrial (?)‐menthol synthesis. Our findings pave the way for a rational enzyme engineering solution.     

Optical properties of rotationally twinned InP nanowire heterostructures

We have developed a technique so that both transmission electron microscopy and microphotoluminescence can be performed on the same semiconductor nanowire over a large range of optical power, thus allowing us to directly correlate structural and optical properties of rotationally twinned zinc blende InP nanowires. We have constructed the energy band diagram of the resulting multiquantum well heterostructure and have performed detailed quantum mechanical calculations of the electron and hole wave functions. The excitation power dependent blue-shift of the photoluminescence can be explained in terms of the predicted staggered band alignment of the rotationally twinned zinc blende/wurzite InP heterostructure and of the concomitant diagonal transitions between localized electron and hole states responsible for radiative recombination. The ability of rotational twinning to introduce a heterostructure in a chemically homogeneous nanowire material and alter in a major way its optical properties opens new possibilities for band-structure engineering.     

Retrospective reports of parental physical affection and parenting style: A study of Finnish twins.

Individual differences in parenting behaviors are due, in part, to genetic factors. In the present study, the authors sought to determine whether the degree of genetic influence varied according to the type of parental behavior under consideration. A population-based sample of 2,334 pairs of Finnish twins provided ratings on the physical affection, control, abusiveness, and indifference shown by their father and mother during childhood. Genetic influences, shared environmental influences, and nonshared environmental influences accounted for a small-to-medium proportion (17%-30%), a small-to-large proportion (22%-44%), and a medium-to-large proportion (37%-55%) of the variance in each parenting measure, respectively. There were no significant differences in effect sizes for mothers and fathers or across the 4 types of parental behavior. The genetic results may reflect characteristic styles with which parents respond to genetically influenced behaviors of individuals (gene-environment correlations) or individual perceptions of this relationship (gene-person correlation processes). The findings have implications for intervention and prevention work with families and for interpretation of evidence for interactions between genes and parenting behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)