Perylene Diimide as a Precise Graphene-like Superoxide Dismutase Mimetic

Here we show that the active portion of a graphitic nanoparticle can be mimicked by a perylene diimide (PDI) to explain the otherwise elusive biological and electrocatalytic activity of the nanoparticle construct. Development of molecular analogues that mimic the antioxidant properties of oxidized graphenes, in this case the poly(ethylene glycolated) hydrophilic carbon clusters (PEG–HCCs), will afford important insights into the highly efficient activity of PEG–HCCs and their graphitic analogues. PEGylated perylene diimides (PEGn–PDI) serve as well-defined molecular analogues of PEG–HCCs and oxidized graphenes in general, and their antioxidant and superoxide dismutase-like (SOD-like) properties were studied. PEGn–PDIs have two reversible reduction peaks, which are more positive than the oxidation peak of superoxide (O2•–). This is similar to the reduction peak of the HCCs. Thus, as with PEG–HCCs, PEGn–PDIs are also strong single-electron oxidants of O2•–. Furthermore, reduced PEGn–PDI, PEGn–PDI•–, in the presence of protons, was shown to reduce O2•– to H2O2 to complete the catalytic cycle in this SOD analogue. The kinetics of the conversion of O2•– to O2 and H2O2 by PEG8–PDI was measured using freeze-trap EPR experiments to provide a turnover number of 133 s–1; the similarity in kinetics further supports that PEG8–PDI is a true SOD mimetic. Finally, PDIs can be used as catalysts in the electrochemical oxygen reduction reaction in water, which proceeds by a two-electron process with the production of H2O2, mimicking graphene oxide nanoparticles that are otherwise difficult to study spectroscopically

О НОВОЙ ТЕХНОЛОГИИ ПОДГОТОВКИ ГОРЯЧЕЙ ПИТЬЕВОЙ ВОДЫ

The present article contains information concerning the new Cl-anionization technology in the preparation of hot drinking water. In contrast with water softening, that replaces all the hardness salts by sodium cations in the cation exchanger, this new technology makes it possible to replace incrustating HCO3̄ and SO42--anions in a strong-base anion exchanger by Cl⁻-ions. As a result, the incrustation on the surfaces of heating hot water heaters is prevented. Thus, cations of hardness that are valuable for the human body remain in the water, the quality of the latter conforming to drinking water quality. Considering the important role of calcium and magnesium in the human body, in Germany and Turkey the minimum value of hardness cations in drinking water is limited to 2.85 and 7.50 mg-Eqv/l, respectively. According to the World Health Organization, in the composition of drinking water, the concentration of cations of magnesium and calcium is recommended, respectively, within 10–(20–30), and 20–50 mg/l; the minimum value of total hardness is 2–4 mg-Eqv/l. According to the developed technology drinking water is passed consistently in the downward direction through the mechanical and chlorineanionite exchanger filters. In the latter, the main part of HCO3̄ and SO42--water ions are exchanged for Cl-anions of anionite. Then the water is collected in the tank, from where it is pumped to the hot water heater through the ultraviolet disinfection unit. After the depletion of the anionite by HCO3̄ and SO42--anions, it is regenerated by a solution of 8–12 % NaCl. The results of research by the anion exchangers Purolite A200EMBCl and AB-17-8 are plotted. It is noted that when the specific consumption of salt for regeneration is of about 45–55 kg/m³, working exchange capacity of the A200EMBCl occurs to be in the range 300–370 g-Eqv/m³. For anionization of water, the residual concentration of HCO3̄-ions are changed from 0.5 to 3.2 mg-Eqv/l. The average concentration of these anions occurs to be between 1.8 and 2.2 mg-Eqv/l, when their initial value is 4.4 mg-Eqv/l.В статье приводятся сведения о новой технологии Cl-анионирования при подготовке горячей питьевой воды. Указанная технология в отличие от умягчения воды, где все соли жесткости замещаются в катионите катионами натрия, позволяет заменить накипеобразующие HCO-/3- и SO(2-)/4 -анионы в сильноосновном анионите Cl⁻-ионами. В результате предотвращается образование накипи на поверхностях нагрева подогревателей горячего водоснабжения. Таким образом, ценные для человеческого организма катионы жесткости остаются в составе воды, и ее качество удовлетворяет качеству питьевой воды. Учитывая важную роль кальция и магния для человеческого организма, в Германии и Турции ограничивается минимальное значение катионов жесткости в питьевой воде соответственно до 2,85 и 7,50 мг-экв/л. По данным Всемирной организации здравоохранения, в составе питьевой воды концентрация катионов магния и кальция рекомендуется соответственно в пределах 10–(20–30) и 20–50 мг/л; минимальное значение общей жесткости 2–4 мг-экв/л. Согласно разработанной технологии питьевая вода последовательно в направлении сверху вниз пропускается через механический и хлор-анионитный фильтры. В последнем основная часть HCO-/3- и SO(2-)/4-ионов воды обменивается на Cl-анионы анионита. Далее вода собирается в бак, откуда насосом через аппарат ультрафиолетовой дезинфекции подается в подогреватель горячего водоснабжения. После истощения анионита SO(2-)/4- и HCO-/3-анионами осуществляется его регенерация раствором (8–12)%-й NaCl. Излагаются результаты исследований анионитами Purolite A200EMBCl и АВ-17-8. Отмечается, что при удельном расходе соли на регенерацию около 45–55 кг/м³ рабочая обменная емкость A200EMBCl получается в пределах 300–370 г-экв/м³. При анионировании воды остаточная концентрация HCO-/3-ионов изменялась в пределах от 0,5 до 3,2 мг-экв/л. Средняя концентрация этих анионов при исходном их значении, равном 4,4 мг-экв/л, получилась в пределах от 1,8 до 2,2 мг-экв/л

Emergence and intensification of dairying in the Caucasus and Eurasian steppes

Archaeological and archaeogenetic evidence points to the Pontic-Caspian steppe zone between the Caucasus and the Black Sea as the crucible from which the earliest steppe pastoralist societies arose and spread, ultimately influencing populations from Europe to Inner Asia. However, little is known about their economic foundations and the factors that may have contributed to their extensive mobility. Here, we investigate dietary proteins within the dental calculus proteomes of 45 individuals spanning the Neolithic to Greco-Roman periods in the Pontic-Caspian Steppe and neighbouring South Caucasus, Oka-Volga-Don and East Urals regions. We find that sheep dairying accompanies the earliest forms of Eneolithic pastoralism in the North Caucasus. During the fourth millennium Bc, Maykop and early Yamnaya populations also focused dairying exclusively on sheep while reserving cattle for traction and other purposes. We observe a breakdown in livestock specialization and an economic diversification of dairy herds coinciding with aridification during the subsequent late Yamnaya and North Caucasus Culture phases, followed by severe climate deterioration during the Catacomb and Lola periods. The need for additional pastures to support these herds may have driven the heightened mobility of the Middle and Late Bronze Age periods. Following a hiatus of more than 500 years, the North Caucasian steppe was repopulated by Early Iron Age societies with a broad mobile dairy economy, including a new focus on horse milking.Peer reviewe

Emergence and intensification of dairying in the Caucasus and Eurasian steppes

Archaeological and archaeogenetic evidence points to the Pontic-Caspian steppe zone between the Caucasus and the Black Sea as the crucible from which the earliest steppe pastoralist societies arose and spread, ultimately influencing populations from Europe to Inner Asia. However, little is known about their economic foundations and the factors that may have contributed to their extensive mobility. Here, we investigate dietary proteins within the dental calculus proteomes of 45 individuals spanning the Neolithic to Greco-Roman periods in the Pontic-Caspian Steppe and neighbouring South Caucasus, Oka-Volga-Don and East Urals regions. We find that sheep dairying accompanies the earliest forms of Eneolithic pastoralism in the North Caucasus. During the fourth millennium Bc, Maykop and early Yamnaya populations also focused dairying exclusively on sheep while reserving cattle for traction and other purposes. We observe a breakdown in livestock specialization and an economic diversification of dairy herds coinciding with aridification during the subsequent late Yamnaya and North Caucasus Culture phases, followed by severe climate deterioration during the Catacomb and Lola periods. The need for additional pastures to support these herds may have driven the heightened mobility of the Middle and Late Bronze Age periods. Following a hiatus of more than 500 years, the North Caucasian steppe was repopulated by Early Iron Age societies with a broad mobile dairy economy, including a new focus on horse milking.Peer reviewe

Oxygen-rich microporous carbons with exceptional hydrogen storage capacity

Porous carbons have been extensively investigated for hydrogen storage but, to date, appear to have an upper limit to their storage capacity. Here, in an effort to circumvent this upper limit, we explore the potential of oxygen-rich activated carbons. We describe cellulose acetatederived carbons that combine high surface area (3800 m2 g-1) and pore volume (1.8 cm3 g-1) that arise almost entirely (> 90%) from micropores, with an oxygen-rich nature. The carbons exhibit enhanced gravimetric hydrogen uptake (8.1 wt% total, and 7.0 wt% excess) at -196 ºC and 20 bar, rising to a total uptake of 8.9 wt% at 30 bar, and exceptional volumetric uptake of 44 g l-1 at 20 bar, and 48 g l-1 at 30 bar. At room temperature they store up to 0.8 wt% (excess) and 1.2 wt% (total) hydrogen at only 30 bar, and their isosteric heat of hydrogen adsorption is above 10 kJ mol-1

Emergence and intensification of dairying in the Caucasus and Eurasian steppes

Archaeological and archaeogenetic evidence points to the Pontic-Caspian steppe zone between the Caucasus and the Black Sea as the crucible from which the earliest steppe pastoralist societies arose and spread, ultimately influencing populations from Europe to Inner Asia. However, little is known about their economic foundations and the factors that may have contributed to their extensive mobility. Here, we investigate dietary proteins within the dental calculus proteomes of 45 individuals spanning the Neolithic to Greco-Roman periods in the Pontic-Caspian Steppe and neighbouring South Caucasus, Oka-Volga-Don and East Urals regions. We find that sheep dairying accompanies the earliest forms of Eneolithic pastoralism in the North Caucasus. During the fourth millennium Bc, Maykop and early Yamnaya populations also focused dairying exclusively on sheep while reserving cattle for traction and other purposes. We observe a breakdown in livestock specialization and an economic diversification of dairy herds coinciding with aridification during the subsequent late Yamnaya and North Caucasus Culture phases, followed by severe climate deterioration during the Catacomb and Lola periods. The need for additional pastures to support these herds may have driven the heightened mobility of the Middle and Late Bronze Age periods. Following a hiatus of more than 500 years, the North Caucasian steppe was repopulated by Early Iron Age societies with a broad mobile dairy economy, including a new focus on horse milking.</p

MORE DEVELOPMENT OF BANKS 'MONETARY, CRYPTO CURRENCY AND BLOCKCHAIN POLICY IN THE DIGITAL ECONOMY

In the current context of the development of monetary and financial relations in the banking system of Uzbekistan, it is important to study the exchange and characteristics of blockchain and cryptocurrencies, which are their innovative forms

A DFT and TDDFT Study of Alkylated Trimethylene-Bridged Bis(p-Phenylenediamines)

The conclusions are: (1) LDA predicts fairly well the structures of {pi}-dimers. This has been reported before. Here we show that even the small difference between conformers can be described by LDA. Electron densities suggest a stronger bond is formed in LDA than B3LYP. (2) Though its good performance is possibly due to error cancelations, LDA may be used as a practical tool for large {pi}-dimer systems. (3) TDDFT once again does a good job for the optical transitions. The near-IR band shows a weak dependence on the functional, but a stronger one on the interplanar distance

Didactic Features Of The Modern Lesson

The identity of the student is a key component of the Uzbek education law. Activating the individual in the learning process is the main task of every teacher in the professional education system

More Development of Banks 'Monetary, Crypto Currency and Blockchain Policy in the Digital Economy

In the current context of the development of monetary and financial relations in the banking system of Uzbekistan, it is important to study the exchange and characteristics of blockchain and cryptocurrencies, which are their innovative forms