Модификация пероксинитритом как способ улучшения цитосовместимости гидрогелей на основе альгината натрия

Sodium alginate is one of the most frequently used materials in biomedicine. However, alginate-based scaffolds have extremely low adhesive properties and have to be improved. The authors have proposed combined hydrogels of gelatin and sodium alginate which have been modified by peroxynitrite in heterophasic conditions using ethanol. It has been determined that thus modified sodium alginate contains an increased level of carbonyl, carboxyl and nitro groups. Authors have developed chemically and chemical-enzymatically cross-linked hydrogels with better adhesive properties and absence of cytotoxicity. Moreover, sodium alginate modification has a positive impact on cell morphology in comparison with control group of non-adhesive alginate-gelatin hydrogels. It allows the further improvement and application of the biomaterial which have been developed by the authors for bioengineering scaffold production and 3D culturing.Альгинат натрия – один из часто применяемых в биомедицине материалов. Однако скаффолды и гидрогели на его основе обладают крайне слабыми адгезивными свойствами и нуждаются в совершенствовании. Нами предложены комбинированные гидрогели на основе желатина и альгината натрия, модифицированного пероксинитритом в гетерофазных условиях в среде этилового спирта. Модифицированный таким образом альгинат натрия обладает увеличенным содержанием карбонильных, карбоксильных и нитрогрупп. Разработанные авторами ионно и ионно-ферментативно сшитые гидрогели обладают улучшенными адгезивными свойствами и не проявляют цитотоксичности. Кроме того, модификация альгината натрия оказывает положительное влияние на морфологию клеток по сравнению с контрольными неадгезивными альгинат-желатиновыми гидрогелями. Это делает возможным дальнейшее совершенствование и использование разработанного биоматериала для получения биоинженерных скаффолдов и 3D-культивирования

Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

The luminescence properties of highly strained, Sb-doped Ge/Si multi-layer heterostructures with incorporated Ge quantum dots (QDs) are studied. Calculations of the electronic band structure and luminescence measurements prove the existence of an electron miniband within the columns of the QDs. Miniband formation results in a conversion of the indirect to a quasi-direct excitons takes place. The optical transitions between electron states within the miniband and hole states within QDs are responsible for an intense luminescence in the 1.4–1.8 µm range, which is maintained up to room temperature. At 300 K, a light emitting diode based on such Ge/Si QD superlattices demonstrates an external quantum efficiency of 0.04% at a wavelength of 1.55 µm

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world