Molecular architecture influences on material properties of pharmaceutical compounds

Salt formation has extensively been studied as a strategy to improve drug solubility but it has not been explored as a strategy to improve mechanical properties. A better understanding of which factors of the solid state can have an influence in the mechanical properties of pharmaceutical powders can help to optimise and reduce cost of tablet manufacturing. The aim of this study was to form different series of amine salts of flurbiprofen, gemfibrozil and diclofenac and to establish predictive relationships between architectural characteristics and physicochemical and mechanical properties of the salts. For this purpose, three different carboxylic acid drugs were selected: flurbiprofen, gemfibrozil and diclofenac, similar in size but varying in flexibility and shape and three different series of counterions were also chosen: one with increasing bulk and no hydroxyl groups to limit the hydrogen bonding potential; a second one with increasing number of hydroxyl groups and finally a third series, related to the latter in number of hydroxyl groups but with different molecular shape and flexibility. Physico-chemical characterization was performed (DSC, TGA, solubility, intrinsic dissolution rate, particle size, true density) and mechanical properties measured using a compaction replicator. Strained molecular conformations produce weaker compacts as they have higher energy than preferred conformations that usually lie close to energy minimums and oppose plastic deformation. It was observed that slip planes, which correspond to regions of weakest interaction between the planes, were associated with improved plasticity and stronger compacts. Apart from hydrogen bonds, profuse van der Waals forces can result in ineffective slip planes. Salts displaying two-dimensional densely hydrogen bonded layers produced stronger compacts than salts showing one-dimensional networks of non-bonded columns, probably by reducing the attachment energy between layers. When hydrogen bonds are created intramolecularly, it is possible that the mechanical properties are compromised as they do not contribute so much to create twodimensional densely bonded layers and they can force molecules into strained conformations. Some types of hydrogen bonding network may be associated with improved mechanical properties, such as type II, or R (10) 3 4 using graph-set notation, versus type III, or R (12) 4 8 , columns. This work clearly demonstrates the potential of investigating crystal structure-mechanical property relationship in pharmaceutical materials.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Opportunistic Macroalgae as a Component in Assessment of Eutrophication

For the last few decades, coastal eutrophication with the associated mass development of opportunistic macroalgae has increased on a global scale. Since the end of the 2000’s, the number of studies of macroalgal blooms also increased many times. Mass occurrences of such species as Cladophora spp., Ulva spp., and Spirogyra spp. caused a necessity to improve existing methods of ecological assessment and develop new ones. There are many indices based on macroalgae and developed for marine and estuarine ecosystems. However, for correct evaluation, they demand a presence of a number of species, including perennial species from the order Fucales. This requirement cannot be satisfied in fresh or brackish waters, including some estuaries, because often, the freshwater communities are dominated by only one or two opportunistic species. The present paper defines the most relevant topics in studies of macroalgal blooms and reviews indices and metrics which can be recommended for the ecological assessment in diverse habitats influenced or dominated by opportunistic macroalgae species. For ecological assessment of opportunistic communities, according to their seasonal peculiarities, the author recommends, besides biomass, involving evaluation of algal mats (thickness, coverage) and signs of hypoxia

Green tides: new consequences of the eutrophication of natural waters (Invited Review).

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.В последние десятилетия, наряду со сравнительно хорошо изученным “цветением”, вызываемым фитопланктоном, глобальное распространение получило “цветение” морских и пресных вод, обусловленное литоральными донными макроводорослями трех родов: Ulva, Cladophora и Spirogyra. В настоящем обзоре предпринята попытка приблизиться к пониманию, почему именно эти таксоны зеленых нитчатых водорослей начинают бурно расти весной во многих водоемах и водотоках, в том числе - в олиготрофных, а затем поднимаются со дна, образуя плавающие маты (метафитон), и их гниющие массы выносятся на берег, что приводит к существенному экологическому и экономическому ущербу. Рассматриваются как отличительные, так и общие эколого-физиологические характеристики Ulva, Cladophora и Spirogyra, способствующие формированию “зеленых приливов”. Хотя очевидной причиной повышения биомассы водорослей является эвтрофирование (поступление азота и фосфора из сельхозугодий, промышленных и бытовых стоков, аквакультуры), выдвинута гипотеза, что для образования “зеленого прилива” ключевую роль играет локализация внешних потоков элементов минерального питания (поверхностный сток или разгрузка грунтовых вод), а также биогенное переключение внутренних потоков азота и фосфора из пелагиали в литораль (бентификация). Обсуждаются меры борьбы с данным явлением. Подчеркивается необходимость более подробного изучения метафитонной стадии вегетации донных макроводорослей. Отмечается, что требуется пересмотр существующей концепции олиготрофных/эвтрофных вод, в которой учитывается только продукция пелагической части водных экосистем

Cyanobacteria and macroalgae in ecosystem of the Neva estuary

The Baltic Sea and Neva estuary are plagued by coastal eutrophication. In order to estimate the scale of the problem, quantitative estimates of phytoplankton and macroalgal mats were determined in the Neva estuary. Long-term monitoring (1982–2009) of phytoplankton showed changes in its species composition and abundance. Summer phytoplankton biomass increased significantly in the 1990s, with concomitant changes in species composition, despite a decline of nutrients in the Neva estuary. The cyanobacteria Planktothrix agardhii became a dominant species. The summer biomass of phytoplankton reached a maximum of 5.2 ± 0.4 mg·L-1 in 2002–2004. Monitoring of macroalgal community in the coastal area of the Neva estuary from 2002 to 2009 showed the dominance of the filamentous green alga Cladophora glomerata in the phytobenthos. Average biomass of macroalgae in inner and outer estuary differed significantly at 132 ± 29 and 310 ± 67 g DW·m-2, respectively. This study showed, that fluctuations in macroalgal biomass reflected human influence on estuary, although it was less sensitive to human impact than the phytoplankton community. Thus qualitative and quantitative characteristics of phytoplankton and macroalgal blooms can indicate anthropogenic influence on the ecosystem, and help to better manage the Neva estuary

Cyanobacteria and macroalgae in ecosystem of the Neva estuary

The Baltic Sea and Neva estuary are plagued by coastal eutrophication. In order to estimate the scale of the problem, quantitative estimates of phytoplankton and macroalgal mats were determined in the Neva estuary. Long-term monitoring (1982–2009) of phytoplankton showed changes in its species composition and abundance. Summer phytoplankton biomass increased significantly in the 1990s, with concomitant changes in species composition, despite a decline of nutrients in the Neva estuary. The cyanobacteria Planktothrix agardhii became a dominant species. The summer biomass of phytoplankton reached a maximum of 5.2 ± 0.4 mg·L-1 in 2002–2004. Monitoring of macroalgal community in the coastal area of the Neva estuary from 2002 to 2009 showed the dominance of the filamentous green alga Cladophora glomerata in the phytobenthos. Average biomass of macroalgae in inner and outer estuary differed significantly at 132 ± 29 and 310 ± 67 g DW·m-2, respectively. This study showed, that fluctuations in macroalgal biomass reflected human influence on estuary, although it was less sensitive to human impact than the phytoplankton community. Thus qualitative and quantitative characteristics of phytoplankton and macroalgal blooms can indicate anthropogenic influence on the ecosystem, and help to better manage the Neva estuary

Environmental Assessment with Cage Exposure in the Neva Estuary, Baltic Sea: Metal Bioaccumulation and Physiologic Activity of Bivalve Molluscs

The rise in anthropogenic impacts on the marine environment requires new water management. The use of a triadic approach (bioaccumulation, bioassay, and physiological biomarkers) has been shown to have good applicability for the comparative assessment of the environmental state of the Neva Estuary (Gulf of Finland, Baltic Sea). The novelty of the methodological approach of the study was that it involved both active and passive bio-monitoring methods for assessing the quality of estuarine environment. The classical analyses of metal concentration in bottom sediments, in field biota (fish and molluscs), and in caged molluscs were accompanied by a bioassay of sediment toxicity using amphipods. The physiological state of molluscs kept in cages was assessed according to two functional characteristics, such as cardio-tolerance and metabolic activity (oxygen consumption rate), after exposition in cages. The method of active monitoring (caging exposure with molluscs) as a measurement of parameters in clean molluscs has proven itself well in controlling the accumulation of both metals and oil products. Macroalgae that are abundant in estuarine ecosystems are also good indicators of metals, at least showing the transition from bottom sediments to the next level of food webs. Unionid molluscs were found to be a more sensitive and effective indicator of contaminant accumulation than dreissenid molluscs, characterized by a low tolerance to changeable environmental conditions in the estuarine ecosystem and rather high mortality in cages. Our results have shown that caging exposure with unionids can be a widely used methodological approach for the assessment of estuarine environmental quality through the determination of metal concentrations in molluscs and their physiological state

Benthic Invertebrates Abundance and Trophic Links in the Coastal Zone during <i>Cladophora</i> Blooms

The green macroalga Cladophora glomerata, a species typical of brackish water, predominates in most coastal areas of estuarine ecosystems. The present study aimed to determine the current ecological conditions in the Neva estuary (Baltic Sea) when subjected to eutrophication and the summer Cladophora bloom. Macroalgae bloom can result in temporary unfavorable conditions (oxygen depletion and pollution) for invertebrates during macroalgae decomposition, and its contribution to the autochthonous benthic food web remains unclear. We evaluated the Cladophora biomass and the abundance and composition of macro- and meiobenthic invertebrates and traced trophic links in the coastal area of the Neva estuary during the Cladophora bloom. Some species of grazing or omnivorous consumers (nematodes, gastropods, amphipods, insect larvae) reached high abundance in the Cladophora-dominated coastal community. The tracing of food sources in a food chain of the Cladophora-dominated coastal community (macrophytes-grazers-omnivores) were elucidated using dual δ13C and δ15N stable isotope analysis. The results showed that autochthonous organic sources derived from Cladophora at various stages might contribute notably (up to 89%) to the coastal food web, supporting the production of benthic consumers

Heavy Metal Content in Macroalgae as a Tool for Environmental Quality Assessment: The Eastern Gulf of Finland Case Study

Macroalgae are widely used for bioindication and assessment; however, in the case of pollutants of different origin, it is still unclear which contaminants in thalli can be regarded as indicative because too many factors influence the ability of algae to uptake them. The present study is a part of an international HAZLESS project and was conducted in the eastern Gulf of Finland (GoF). The main goal of our study was the application of metal concentrations in macroalgae as a tool for environmental quality assessment. To achieve this goal, we calculated the threshold metal concentrations in macroalgae (Cladophora glomerata) and compared our obtained values with actual concentrations. We found significant Spearman correlations in May between metals in sediments and pore water (−0.73 for Zn, −0.62 for Cd, 0.85 for Pb) and also between metals in algae and metals in pore water (1 for Cu and Cd, 0.98 for Zn and Pb). In July, Pb in algae were significantly correlated with Pb in pore water (0.88). The application of the calculated environmental quality standard (EQSMPC) for macroalgae has shown moderate pollution by Cu and Pb in the coastal zone of the eastern GoF. This was confirmed by an assessment based on the comparisons of metal concentrations in water with Environmental Quality Standards for water (EQSw). However, differences in the bioaccumulation factor and EQSMPC between May and July have shown that it is necessary to compare samples taken during the same period every year for adequate results in long-term monitoring. Considering the sensitivity of accumulating processes to the surrounding environment, we believe that in the case of habitats with diverse conditions, even for the same species of algae, threshold values should be calculated and used individually for every habitat. Our results have shown that this approach can be widely used for an assessment of environmental quality via metal concentrations in opportunistic macroalgae and can be recommended for further use

Ecological and phylogenetic aspects of the spring diet of three palaearctic species of swans

Abstract The quality of swans' nutrition at spring migration stopovers is important for their successful breeding. It is of great interest to study the differences in nutrition of different swan species when sharing the same habitat. Microscopic analysis of Cygnus olor, C. cygnus, and C. columbianus bewickii feces collected in the eastern part of the Gulf of Finland in February-April 2014–2019 was performed. We measured food preferences of the three swan species using non-metric multidimensional scaling (NMDS). The width and overlap of dietary niches were also calculated. The diet of C. olor consists almost entirely of soft submerged aquatic vegetation, mainly macroalgae. Samples of the other two species except macroalgae contained large amounts of young shoots and roots of rigid semi-submerged and coastal vegetation. The dietary niche of C. cygnus is the most isolated because it is dominated by thick rhizomes of Phragmites australis, which are hardly used by other swan species. The diet of Bewick’s swans was similar in many respects to that of the Mute swan, but Bewick’s swans much more often preferred vegetative parts of submerged and semi-submerged plants, such as Stuckenia pectinata, Potamogeton perfoliatus, Sparganium sp., Nuphar lutea, and others. Notably, the dietary niches of Mute swan and Whooper swan overlapped as much as possible in February March during a period of severe food shortage, in contrast to later periods in spring when food was more abundant and varied. In general, differences in diets are well explained by differences in the morphology of birds. Comparison of tarsometatarsus indices shows that C. olor is the most water-related species. C. olor has the longest neck and its beak has the strongest filter features, whereas beaks of the other two species shows noticeable “goose-like grazing” features. Moreover, C. Cygnus has the most powerful beak. These features are due to the history of species. The formation of C. olor occurred during the Miocene-Pliocene of the Palaearctic in the warm eutrophic marine lagoons of the Paratethys with abundant soft submerged vegetation. The evolution of C. cygnus and C. c. bewickii took place in Pleistocene. At that time, periglacial and thermokarst water bodies on permafrost became widespread in the Palearctic, as well as dystrophic peat lakes with much poorer submerged aquatic vegetation, but well-developed coastal and semi-submerged vegetation