α-pinene photooxidation under controlled chemical conditions – Part 2: SOA yield and composition in low- and high-NO_x environments

The gas-phase oxidation of α-pinene produces a large amount of secondary organic aerosol (SOA) in the atmosphere. A number of carboxylic acids, organosulfates and nitrooxy organosulfates associated with α-pinene have been found in field samples and some are used as tracers of α-pinene oxidation. α-pinene reacts readily with OH and O_3 in the atmosphere followed by reactions with both HO_2 and NO. Due to the large number of potential reaction pathways, it can be difficult to determine what conditions lead to SOA. To better understand the SOA yield and chemical composition from low- and high-NO_x OH oxidation of α-pinene, studies were conducted in the Caltech atmospheric chamber under controlled chemical conditions. Experiments used low O_3 concentrations to ensure that OH was the main oxidant and low α-pinene concentrations such that the peroxy radical (RO_2) reacted primarily with either HO_2 under low-NO_x conditions or NO under high-NO_x conditions. SOA yield was suppressed under conditions of high-NO_x. SOA yield under high-NO_x conditions was greater when ammonium sulfate/sulfuric acid seed particles (highly acidic) were present prior to the onset of growth than when ammonium sulfate seed particles (mildly acidic) were present; this dependence was not observed under low-NO_x conditions. When aerosol seed particles were introduced after OH oxidation, allowing for later generation species to be exposed to fresh inorganic seed particles, a number of low-NO_x products partitioned to the highly acidic aerosol. This indicates that the effect of seed acidity and SOA yield might be under-estimated in traditional experiments where aerosol seed particles are introduced prior to oxidation. We also identify the presence of a number of carboxylic acids that are used as tracer compounds of α-pinene oxidation in the field as well as the formation of organosulfates and nitrooxy organosulfates. A number of the carboxylic acids were observed under all conditions, however, pinic and pinonic acid were only observed under low-NO_x conditions. Evidence is provided for particle-phase sulfate esterification of multi-functional alcohols

Heavy metal accumulation by Acer platanoides and Robinia pseudoacacia in an industrial city (Northern Steppe of Ukraine)

The role of tree species as a tool for bioaccumulation of heavy metals is an important current issue within the context of the increase of anthropogenic pressure in urban ecosystems. The article presents the results of research on the level of soil contamination with heavy metals and the processes of their accumulation by native and introduced tree species in green spaces of Dnipro city. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect concentrations of heavy metals (Zn, Cu, Cd, Pb) in soil samples and the assimilation component in trees of black locust (Robinia pseudoacacia) and Norway maple (Acer platanoides). The ranges of mean concentrations of heavy metals at different study sites within the city’s green infrastructure were as follows (mg/kg): 30.7–185.5 for Zn, 5.7–22.4 for Cu, 9.0–31.3 for Pb, and 0.213–0.598 for Cd. With respect to all four of these metals, the soils of the Metallurgists Square location were characterized by the highest concentrations of the metals, and the Pridneprovsky Park in the area of the outskirts of Dnipro city was characterized by the lowest ones. Compared to soils, the two investigated tree species had a significantly lower content of all studied metals in leaves. The heavy metal accumulations in the leaves of both R. pseudoacacia and A. platanoides were observed in the following decreasing order: Zn > Cu > Pb > Cd. Regarding the migration of heavy metals in the soil-plant system, the concentrations of ecopollutants in the plants were found not to be dependent on their content in the soil environment. The calculated bioaccumulation coefficients of heavy metals for both tree species were < 1. However, the results of heavy metal concentration in leaves of both introduced and native tree species evidenced their special role in heavy metal bioaccumulation. Compared to R. pseudoacacia, such native species as A. platanoides can be considered to be a more “sensitive” bioindicator of environmental pollution caused by heavy metals. Planting fast-growing tree species such as R. pseudoacacia and A. platanoides can in a short time be an environmentally appropriate and cost-effective measure to mitigate the unfavourable effects of heavy metals on the environment

Features of forming an invertebrate fauna in technogen environment (Kriviy Rig, Ukraine)

The features of invertebrate fauna forming in conditions of technogen pressure (Kriviy Rig, Ukraine) were studied. The taxonomic composition, dominance structure and correlation of soil invertebrates’ functional groups in the large industrial enterprises were examined. It had been found that a small thickness of the soil layer as a habitat for ground animals causes the depletion of taxonomic composition, species richness and decrease the total number of soil invertebrates. Gastropoda molluscs in conditions of technogen pressure are the most adapted to stresses group of invertebrates

Біохімічна оцінка загоєння післяопераційних ран на фоні цукрового діабету в щурів при різних способах закриття ран

Introduction. Wound healing according to modern concepts is a coordinated process that passes through certain stages with the participation of different cells and products of its vital functions that regulate the healing process. It is well known that in patients with diabetes there is a violation of the process of wound healing, although until now, all the features of diabetes underlying such an inclination have not been fully understood.The aim of the study – to identify the features of oxidative stress on the background of diabetes mellitus in the rat's homogenate when different methods of closing wounds had been used. Research Methods. The experiment was conducted on 60 male rats weighing 280–320 g, which pre-simulated diabetes mellitus and surgical wounds. To detect the activation of free radical oxidation processes, the content of active forms of oxygen (AFC), lipid hydroperoxides (HPL), diene conjugates (DK) and trienic conjugates (TC) and oxidation modifications of proteins (OMP370 and OMP430). To study the antioxidant defense system, activity of superoxide dismutase was determined. Also, the activity of catalase and sulfhydryl groups (SH-groups) was determined.Results and Discussion. The research conducted by us showed that during the wounded process, on the background of diabetes, the activity of free radical oxidation processes increased. However, in the animal skin homogenates, which are labeled "Dermabond", all indices are significantly lower than in the group of animals that have been sewed over the course of all research periods. In the early stages of scar formation (3 days), an increase in the activity of the antioxidant defense system in both groups was observed. At the same time, in the experimental group of animals, which imposed the nodal seams, the activity of SOD and catalase significantly exceeded the skin index of animals, which applied glue and made (199.81±7.59) UM and (175.02±8.31) cat/kg, respectively.Conclusion. The use of skin glue reduces the intensity of the course of free radical oxidation in the cells of the scar tissue of the postoperative wound in conditions of diabetes mellitus in comparison with the imposition of nodal sutures on it: in the skin of animals, which is applied to the "Dermabond" glue, all indicators are significantly lower than in the group of animals, which imposed seam joints, throughout all research periods. Вступление. По современным представлениям, заживление ран – это скоординированный процесс, который проходит через определенные стадии с участием различных клеток и продуктов их жизнедеятельности, регулирующих процесс заживления. У больных диабетом нарушается процесс раневого заживления, хотя до сих пор до конца не изучены все особенности заболевания, лежащие в основе такой склонности.Цель исследования – выявить особенности оксидативного стресса на фоне сахарного диабета в гомогенате кожи крыс при различных способах закрытия ран.Методы исследования. Эксперимент проведен на 60 крысах-самцах массой 280–320 г, которым предварительно смоделировали сахарный диабет и операционные раны. Для выявления активации процессов свободнорадикального окисления определяли содержание активных форм кислорода, гидроперекисей липидов, диеновых и триенових конъюгатов и показателей окислительной модификации белков (ОМБ370 и ОМБ430). С целью изучения системы антиоксидантной защиты определяли активность супероксиддисмутазы. Также определяли активность каталазы и сульфгидрильных групп.Результаты и обсуждение. При раневом процессе на фоне сахарного диабета возрастала активность свободнорадикального окисления. Однако в гомогенатах кожи животных, которым нанесли клей “Dermabond”, все показатели были достоверно ниже, чем в группе крыс, которым наложили узловые швы, на протяжении всех сроков исследования. На ранних этапах формирования рубца (на 3-е сутки) наблюдали возрастание показателей активности системы антиоксидантной защиты в обеих группах. При этом в экспериментальной группе животных, которым наложили узловые швы, активность супероксиддисмутазы и каталазы значительно превышала показатели в коже крыс, которым нанесли клей, и составила (199,81±7,59) у. е. и (175,02±8,31) кат/кг соответственно.Выводы. Применение кожного клея снижает интенсивность протекания свободнорадикального окисления в клетках рубцевоизмененных тканей послеоперационной раны при сахарном диабете по сравнению с наложением на нее узловых швов: в гомогенатах кожи животных, которым нанесли клей “Dermabond”, все показатели достоверно ниже, чем в группе крыс, которым наложили узловые швы, на протяжении всех сроков исследования. Вступ. За сучасними уявленнями, загоєння ран – це скоординований процес, який проходить через певні стадії з участю різних клітин і продуктів їх життєдіяльності, що регулюють процес загоєння. У хворих на діабет порушкється процес ранового загоєння, хоча досі до кінця не вивчено всіх особливостей захворювання, що лежать в основі такої схильності.Метадослідження – виявити особливості оксидативного стресу на фоні цукрового діабету в гомогенаті шкіри щурів при різних способах закриття ран.Методи дослідження. Експеримент проведено на 60 щурах-самцях масою 280–320 г, яким попередньо змоделювали цукровий діабет та операційні рани. Для виявлення активації процесів вільнорадикального окиснення визначали вміст активних форм кисню, гідропероксидів ліпідів, дієнових і трієнових кон’югатів та показників окисної модифікації білків (ОМБ370 і ОМБ430). З метою вивчення системи антиоксидантного захисту визначали активність супероксиддисмутази. Також визначали активнiсть каталази і сульфгідрильних груп.Результати й обговорення. При рановому процесі на фоні цукрового діабету зростала активність вільнорадикального окиснення. Однак у гомогенатах шкіри тварин, яким нанесли клей “Dermabond”, усі показники були достовірно нижчими, ніж у групі щурів, яким наклали вузлові шви, впродовж усіх термінів дослідження. На ранніх етапах формування рубця (на 3-тю добу) спостерігали зростання показників активності системи антиоксидантного захисту в обох групах. При цьому в експериментальній групі тварин, яким наклали вузлові шви, активність супероксиддисмутази і каталази значно перевищувало показники у шкірі щурів, яким нанесли клей, і становила (199,81±7,59) ум. од. та (175,02±8,31) кат/кг відповідно.Висновки. Застосування шкірного клею знижує інтенсивність перебігу вільнорадикального окиснення у клітинах рубцевозмінених тканин післяопераційної рани за умов цукрового діабету порівняно з накладанням на неї вузлових швів: у гомогенатах шкіри тварин, яким нанесли клей “Dermabond”, усі показники достовірно нижчі, ніж у групі щурів, яким наклали вузлові шви, впродовж усіх термінів дослідження.

Особливості перебігу вільнорадикального окиснення в гомогенаті шкіри щурів при різних способах закриття ран

According to different authors from 4 % to 22 % of patients who applied to medical institutions have abnormal scars. The aim of our research was to identify the characteristics of oxidative stress in skin homogenate of rats with different methods of wound closure. Analysis of all indicators allows to assert that intensity of free radical oxidation in the skin of the animals after applying skin glue is much lower compared to the animals after suturing. In further research is planned to analyze indicators of free radical oxidation system antioxidation protection and reparative ability of the skin when used sutures and biological glue in rats with the diabetes.По данным различных авторов, от 4 до 22 % пациентов, обратившихся в лечебные учреждения, имеют патологические рубцы. Цель данной работы – выявить особенности оксидативного стресса в гомогенате кожи крыс при различных способах закрытия ран. Анализ всех показателей позволяет утверждать, что в коже животных, которым был нанесен клей, интенсивность процессов свободнорадикального окисления значительно ниже по сравнению с наложением узловых швов. В дальнейших исследованиях планируется провести анализ показателей свободнорадикального окисления, системы антиоксидантной защиты и репаративной способности кожи в условиях использования нитей и биологического клея при заболевании сахарным диабетом.За даними різних авторів, від 4 до 22 % пацієнтів, які звернулися до лікувальних закладів, мають патологічні рубці. Мета даної роботи – виявити особливості оксидативного стресу в гомогенаті шкіри щурів при різних способах закриття ран. Аналіз всіх показників дає змогу стверджувати, що у шкірі тварин, яким було нанесено клей, інтенсивність процесів вільнорадикального окиснення значно нижча порівняно з накладанням вузлових швів. У подальших дослідженнях планується провести аналіз показників вільнорадикального окиснення, системи антиоксидантного захисту і репаративної здатності шкіри за умови використання ниток та біологічного клею при захворюванні на цукровий діабет

Study of the intensity of microbial contamination and nonspecific immunity under the experimental diabetes after using different ways of fixing the wound edges

Diabetes mellitus and its complications are one of the most important causes of death. As a consequence of hyperglycemia in patients with diabetes there is an increased risk of concomitant diseases, and one of the important consequences of diabetes is impaired ability to repair. Healing disorders in diabetes are the result of complex pathophysiology involving vascular, neuropathic, immune and biochemical componentsAim of research: was to analyze changes in inflammation markers, microbial contamination and nonspecific immunity in skin homogenate of rats with diabetes after using sutures and skin glue.Material and research methods. Experimental studies were performed on 130 white outbred adult male rats, weight from 240 to 320 g. Diabetes mellitus was induced by using streptozotocin (Sigma, USA) (intraperitoneally - 65 mg / kg) with previous (15 minutes) injection of nicotinamide (intraperitoneally - 230 mg / kg). On the background of obesity, which was caused by 4 weeks of keeping animals on a high-fat diet. The development of diabetes mellitus 2 was confirmed by determining the concentration of glucose in the blood using a glucometer BAYER Contour Next (Germany). Animals of all groups (I-IV) under thiopental anesthesia (40 mg / kg body weight of rats) were made full-layer rectilinear incisions, 2 cm long, in the anterior-lateral region of the abdomen. All animals were divided into 4 experimental groups: І group (30 rats) – healthy rats, wound edges were sutured with Vicryl 5/0 thread (ETHICON, Inc. and Johnson & Johnson company (USA); ІI group (30 rats) – healthy rats, fixing of the wound edges was performed by applying skin glue Dermabond (ETHICON, Inc. and Johnson & Johnson company (USA)); ІII group (30 rats) – rats with diabetes mellitus, wound edges were sutured with Vicryl 5/0 thread; IV group (30 rats) – Rats with diabetes mellitus, fixing of the wound edges was performed by applying skin glue Dermabond. For control, all the results were compared with those of intact animals (10 rats). Animals were removed from the experiment on 3, 7, 28 days after surgery under thiopental anesthesia (90 mg / kg body weight of rats).The degree of contamination of the wound with opportunistic and pathogenic microflora determined by the level of urease activity using Nessler's reagent. Lysozyme activity was determined by bacteriolytic method, using as a substrate a suspension of bacteria Micrococcus lysodeicticus.Results. The obtained results prove that the wound process under conditions of streptozotocin diabetes mellitus in rats leads to a significantly greater contamination of the wound with pathogenic and opportunistic microflora and a decrease in nonspecific immunity, compared with healthy animals. Also, different effects of suture materials on the indicators of microbial contamination and immune protection were found: significantly larger deviations from the norm were found in groups of rats, where we used surgical sutures to fix the wound edges. When comparing the intensity of microbial contamination and nonspecific immunity in the long term (28 days) in the homogenate of the skin of rats with diabetes mellitus and the use of skin glue, the level of urease was 27.3% lower and the level of lysozyme 7.0% lower than in III group where we used surgical sutures.Changes in the activity of the antimicrobial enzyme lysozyme allow to assess the state of nonspecific immunity in the studied tissues. Many authors note a decrease in lysozyme activity in various bioliquids and tissues in diabetes mellitus. The results of our studies prove a significant decrease in the activity of lysozyme in the homogenate of postoperative skin wounds of rats with diabetes.Conclusion. Wound process in rats with experimental diabetes mellitus leads to reliable contamination of the wound with pathogenic and opportunistic microflora, as evidenced by increased urease activity, and reduced nonspecific immunity, characterized by reduced lysozyme activity in the homogenate of postoperative wound/scar tissue in relation to intact animals during all the terms of observation.In the remote period (28 days) in the skin homogenate of rats with diabetes where skin glue was used for wound closure, the level of urease was 27.3% lower and the level of lysozyme was 7.0% lower than that of rats with diabetes, where surgical sutures were used

α-pinene photooxidation under controlled chemical conditions – Part 1: Gas-phase composition in low- and high-NO_x environments

The OH oxidation of α-pinene under both low- and high-NO_x environments was studied in the Caltech atmospheric chambers. Ozone was kept low to ensure OH was the oxidant. The initial α-pinene concentration was 20–50 ppb to ensure that the dominant peroxy radical pathway under low-NO_x conditions is reaction with HO_2, produced from reaction of OH with H_2O_2, and under high-NO_x conditions, reactions with NO. Here we present the gas-phase results observed. Under low-NO_x conditions the main first generation oxidation products are a number of α-pinene hydroxy hydroperoxides and pinonaldehyde, accounting for over 40% of the yield. In all, 65–75% of the carbon can be accounted for in the gas phase; this excludes first-generation products that enter the particle phase. We suggest that pinonaldehyde forms from RO_2 + HO_2 through an alkoxy radical channel that regenerates OH, a mechanism typically associated with acyl peroxy radicals, not alkyl peroxy radicals. The OH oxidation and photolysis of α-pinene hydroxy hydroperoxides leads to further production of pinonaldehyde, resulting in total pinonaldehyde yield from low-NO_x OH oxidation of ~33%. The low-NO_x OH oxidation of pinonaldehyde produces a number of carboxylic acids and peroxyacids known to be important secondary organic aerosol components. Under high-NO_x conditions, pinonaldehyde was also found to be the major first-generation OH oxidation product. The high-NO_x OH oxidation of pinonaldehyde did not produce carboxylic acids and peroxyacids. A number of organonitrates and peroxyacyl nitrates are observed and identified from α-pinene and pinonaldehyde

Role of aldehyde chemistry and NO_x concentrations in secondary organic aerosol formation

Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C_4-unsaturated aldehyde) under urban high-NO_x conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NO_x regime. Here we show that as a result of this chemistry, NO_2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NO_x effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO_2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO_2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO_2) formation is structurally unfavorable. At atmospherically relevant NO_2/NO ratios (3–8), the SOA yields from isoprene high-NO_x photooxidation are 3 times greater than previously measured at lower NO_2/NO ratios. At sufficiently high NO_2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO_2 can exceed that from RO_2+HO_2 reactions under the same inorganic seed conditions, making RO_2+NO_2 an important channel for SOA formation

Synthesis of positively and negatively charged silver nanoparticles and their deposition on the surface of titanium

Bacterial infections related to dental implants are currently a significant complication. A good way to overcome this challenge is functionalization of implant surface with Ag nanoparticles (NPs) as antibacterial agent. This article aims at review the synthesis routes, size and electrical properties of AgNPs. Polyvinyl pyrrolidone (PVP) and polyethyleneimine (PEI) were used as stabilizers. Dynamic Light Scattering, Nanoparticle Tracking Analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) have been used to characterize the prepared AgNPs. Two types of NPs were synthesized in aqueous solutions: PVP-stabilized NPs with a diameter of the metallic core of 70 ± 20 nm, and negative charge of -20 mV, PEI-stabilized NPs with the size of the metallic core of 50 ± 20 nm and positive charge of +55 mV. According to SEM results, all the NPs have a spherical shape. Functionalization of the titanium substrate surface with PVP and PEI-stabilized AgNPs was carried out by dropping method. XRD patterns revealed that the AgNPs are crystalline with the crystallite size of 14 nm