Protein-based materials, toward a new level of structural control

Through billions of years of evolution nature has created and refined structural proteins for a wide variety of specific purposes. Amino acid sequences and their associated folding patterns combine to create elastic, rigid or tough materials. In many respects, nature’s intricately designed products provide challenging examples for materials scientists, but translation of natural structural concepts into bio-inspired materials requires a level of control of macromolecular architecture far higher than that afforded by conventional polymerization processes. An increasingly important approach to this problem has been to use biological systems for production of materials. Through protein engineering, artificial genes can be developed that encode protein-based materials with desired features. Structural elements found in nature, such as β-sheets and α-helices, can be combined with great flexibility, and can be outfitted with functional elements such as cell binding sites or enzymatic domains. The possibility of incorporating non-natural amino acids increases the versatility of protein engineering still further. It is expected that such methods will have large impact in the field of materials science, and especially in biomedical materials science, in the future

Design of a fast in situ infrared diagnostic tool

Conventional Fourier transform IR (FTIR) spectroscopes cannot be used to perform real time in situ IR reflection absorption spectroscopy at monolayer sensitivity for high deposition rates (a couple of tens to hundreds of nm/s) which can be obtained when using an expanding thermal deposition plasma. Therefore a new anal. tool has been developed. The tool is based on a fast optical scanner in combination with conventional grating technol. This results in a loss of spectral range with respect to FTIR spectroscopes, but a significant gain is obtained in time resoln. For the combination used this makes it possible to measure at time resoln. as low as 1.3 ms and resoln. of 24 cm-1 at 1000 cm-1. The absorption sensitivity for single reflection at the best time resoln. is approx. 10-2, but can be improved by using signal enhancement techniques. Here attenuated total reflection is used and the best sensitivity obtained is approx. 10-3, which is close to monolayer sensitivity for various absorption bands in the IR spectrum of silicon oxide films. Monolayer sensitivity can be obtained by averaging multiple spectra, however this will cause the time resoln. to decreas

Argon ion-induced dissociation of acetylene in an expanding Ar/C2H2 plasma

Mass spectrometric and Langmuir probe measurements reveal that the plasma chemistry of an expanding Ar/C2H2 plasma which is used for deposition of hydrogenated amorphous carbon is dominated by argon ion-induced dissociation of the precursor gas. The ion-induced dissociation is very efficient leading to complete depletion under certain conditions. The ion fluence as determined from modeling the mass spectrometry results is in good agreement with Langmuir probe measurements suggesting a one-to-one relation between the argon ion and acetylene consumption. The good correlation found between the growth rate and the acetylene consumption rate expresses the efficient use of the dissociation products. © 1999 American Institute of Physics. © 1999 American Institute of Physic

On shifting ground

This research paper explores some of the transition/tension between the past and the present (old and the new) in the current socio/political transformation. Through the trajectory of my own Norwegian background, I will investigate the use of heritage and ‘soft’ nationalism within formation of national identity, and look at some artists’ response to the current political discourse, through both their art making or writing. By investigating two distinctive symbols of national heritage, the bunad and Borre National Park, I hope to shine light on the complicated balancing act of the dichotomy between inclusion and exclusion when embracing national identity through a common history. The bunad is an increasingly popular, semi-invented national costume, and Borre is the largest burial site from the Viking era in Scandinavia. Furthermore, I will also explore social anthropological thinking around Eric Hobsnawn’s concept of ‘the invention of tradition’. The paper will look at the significance of the landscape and geographical identity, as well as the symbioses between place and the concept of the nation state. Inserted into this, I will discuss some of the outcomes from the intense changeover from analogue technologies to the digital—generating new practices working across the mediums of photography, film/video and the digital. The hybrid medium specificity of the still-motion is of particular interest to my art practice. This video-formatted offspring of the slideshow allows for an expansion of the photographic medium, by viewing it through a cinematic frame, and in the process generating new narrative opportunities and registration of time. Finally, all the concerns articulated in this research will inform my final artwork exhibited in the SCA Postgraduate Degree show in December 2014; a two-piece video installation entitled On Shifting Ground

Алгоритм функціонування системи захисту

Детально розглянуті алгоритми виявлення атак у середовищі мереж зв'язку.In detail the algorithms of exposure of attacks are considered in the environment of communication network

Chemical Cascading Between Polymersomal Nanoreactor Populations

[EN] Harnessing interactions of functional nano-compartments to generate larger particle assemblies allows studying diverse biological behaviors based on their population states and can lead to the development of smart materials. Herein, thiol-functionalized polymersome nanoreactors are utilized as responsive organelle-like nano-compartments-with inherent capacity to associate into larger aggregates in response to change in the redox state of their environment-to study the kinetics of cascade reactions and explore functions of their collective under different population states. Two nanoreactor populations, glucose oxidase- and horseradish peroxidase-loaded polymersomes, are prepared, and the results of their cascading upon addition of glucose are investigated. The kinetics of resorufin production in associated polymersomes and non-associated polymersome populations are compared, observing a decreased rate upon association. For the associated populations, faster chemical cascading is found when the two types of nanoreactors are associated in a concerted step, as compared to sequential association. The addition of competing agents such as catalase impacts the communication between non-associated polymersomes, whereas such an effect is less pronounced for the associated ones. Altogether, the results showcase the impact of collective associations on enzymatic cascading between organelle-like nanoreactors.Y.A. and A.L.-L. contributed equally to this work. The authors would like to acknowledge the support from the Dutch Ministry of Education, Culture, and Science (Gravitation program 024.001.035 and Spinoza premium) and the ERC Advanced Grant (Artisym 694120).A.L.-L. acknowledges support from the MSCA Cofund project oLife, which has received funding from the European Union's Horizon 2020 research and innovation program under the Grant Agreement 847675; and the Maria Zambrano Program from the Spanish Government funded by NextGenerationEU from the European Union. Dr. Imke Pijpers is thanked for cryo-TEM imaging. Dr. Pascal Welzen is acknowledged for advice and useful discussion on polymer and polymersome preparation.Altay, Y.; Llopis-Lorente, A.; Abdelmohsen, LKEA.; Van Hest, JC. (2023). Chemical Cascading Between Polymersomal Nanoreactor Populations. Macromolecular Chemistry and Physics. 224(1):1-5. https://doi.org/10.1002/macp.20220026915224

Causes of death among people who used illicit opioids in England, 2001–18: a matched cohort study

Background: In many countries, the average age of people who use illicit opioids, such as heroin, is increasing. This has been suggested to be a reason for increasing numbers of opioid-related deaths seen in surveillance data. We aimed to describe causes of death among people who use illicit opioids in England, how causes of death have changed over time, and how they change with age. Methods: In this matched cohort study, we studied patients in the Clinical Practice Research Datalink with recorded illicit opioid use (defined as aged 18–64 years, with prescriptions or clinical observations that indicate use of illicit opioids) in England between Jan 1, 2001, and Oct 30, 2018. We also included a comparison group, matched (1:3) for age, sex, and general practice with no records of illicit opioid use before cohort entry. Dates and causes of death were obtained from the UK Office for National Statistics. The cohort exit date was the earliest of date of death or Oct 30, 2018. We described rates of death and calculated cause-specific standardised mortality ratios. We used Poisson regression to estimate associations between age, calendar year, and cause-specific death. Findings: We collected data for 106 789 participants with a history of illicit opioid use, with a median follow-up of 8·7 years (IQR 4·3–13·5), and 320 367 matched controls with a median follow-up of 9·5 years (5·0–14·4). 13 209 (12·4%) of 106 789 participants in the exposed cohort had died, with a standardised mortality ratio of 7·72 (95% CI 7·47–7·97). The most common causes of death were drug poisoning (4375 [33·1%] of 13 209), liver disease (1272 [9·6%]), chronic obstructive pulmonary disease (COPD; 681 [5·2%]), and suicide (645 [4·9%]). Participants with a history of illicit opioid use had higher mortality rates than the comparison group for all causes of death analysed, with highest standardised mortality ratios being seen for viral hepatitis (103·5 [95% CI 61·7–242·6]), HIV (16·7 [9·5–34·9]), and COPD (14·8 [12·6–17·6]). In the exposed cohort, at age 20 years, the rate of fatal drug poisonings was 271 (95% CI 230–313) per 100 000 person-years, accounting for 59·9% of deaths at this age, whereas the mortality rate due to non-communicable diseases was 31 (16–45) per 100 000 person-years, accounting for 6·8% of deaths at this age. Deaths due to non-communicable diseases increased more rapidly with age (1155 [95% CI 880–1431] deaths per 100 000 person-years at age 50 years; accounting for 52·0% of deaths at this age) than did deaths due to drug poisoning (507 (95% CI 452–562) per 100 000 person-years at age 50 years; accounting for 22·8% of deaths at this age). Mirroring national surveillance data, the rate of fatal drug poisonings in the exposed cohort increased from 345 (95% CI 299–391) deaths per 100 000 person-years in 2010–12 to 534 (468–600) per 100 000 person-years in 2016–18; an increase of 55%, a trend that was not explained by ageing of participants. Interpretation: People who use illicit opioids have excess risk of death across all major causes of death we analysed. Our findings suggest that population ageing is unlikely to explain the increasing number of fatal drug poisonings seen in surveillance data, but is associated with many more deaths due to non-communicable diseases

Controlled Assembly of Macromolecular β-Sheet Fibrils

Construction of functional molecular devices by directed assembly processes is one of the main challenges in the field of nanotechnology. Many approaches to this challenge use biological assembly as a source of inspiration for the build up of new materials with controlled organization at the nanoscale. In particular, the self-assembly properties of β-sheet peptides have been used in the design of supramolecular materials, such as tapes, nanotubes, and fibrils