Deep Impact Mission to Tempel 1 Favours New Explosive Cosmogony of Comets

The assumption that short-period (SP) comets are fragments of massive icy envelopes of Ganymede-like bodies saturated by products of ice electrolysis that underwent global explosions provides a plausible explanation of all known manifestations of comets, including the jet character of outflows, the presence of ions in the vicinity of the nucleus, the bursts and splitting of cometary nuclei, etc., with solar radiation initiating burning of the products of electrolysis in the nucleus. As shown persuasively by numerical simulation carried out in hydrodynamic approximation, the shock wave initiated by the Deep Impact (DI) impactor in the cometary ice saturated originally by the electrolysis products 2H2 + O2 is capable of activating under certain conditions exothermal reactions (of the type O2 + H2 + organics = H2O + CO + HCN + other products of incomplete burning of organics including its light and heavy pyrolyzed compounds, soot, etc.), which will slow down shock wave damping (forced detonation) and increase many times the energy release. As a result, the measured energetics of ejections and outflows from the crater have to exceed the DI energetics. Analysis of different clusters of the DI experiment data confirms these conclusions and expectations and thus it favours the planetary origin of comets.Comment: 21 pages incluging 3 figure

Regulation of the CoA Biosynthetic Complex Assembly in Mammalian Cells

Coenzyme A (CoA) is an essential cofactor present in all living cells. Under physiological conditions, CoA mainly functions to generate metabolically active CoA thioesters, which are indispensable for cellular metabolism, the regulation of gene expression, and the biosynthesis of neurotransmitters. When cells are exposed to oxidative or metabolic stress, CoA acts as an important cellular antioxidant that protects protein thiols from overoxidation, and this function is mediated by protein CoAlation. CoA and its derivatives are strictly maintained at levels controlled by nutrients, hormones, metabolites, and cellular stresses. Dysregulation of their biosynthesis and homeostasis has deleterious consequences and has been noted in a range of pathological conditions, including cancer, diabetes, Reye’s syndrome, cardiac hypertrophy, and neurodegeneration. The biochemistry of CoA biosynthesis, which involves five enzymatic steps, has been extensively studied. However, the existence of a CoA biosynthetic complex and the mode of its regulation in mammalian cells are unknown. In this study, we report the assembly of all five enzymes that drive CoA biosynthesis, in HEK293/Pank1β and A549 cells, using the in situ proximity ligation assay. Furthermore, we show that the association of CoA biosynthetic enzymes is strongly upregulated in response to serum starvation and oxidative stress, whereas insulin and growth factor signaling downregulate their assembly

Recreation and terrain effect on the spatial variation of the apparent soil electrical conductivity in an urban park

Recreation is an important cultural ecosystem service and is able to significantly affect soil heterogeneity and vegetation func-tioning. This study investigated the role of the relief and tree stand density in the apparent soil electrical conductivity variation within an urban park. The most suitable variogram models were assessed to evaluate the autocorrelation of the regression models. The map of the spatial variability of apparent soil electrical conductivity was built on the basis of the most suitable variogram. The experimen-tal polygon was located in the Botanical Garden of Oles Honchar Dnipro National University (Dnipro City, Ukraine). The experi-mental polygon was formed by a quasi-regular grid of measurement locations located about 30 m apart. The measurements of the apparent electrical conductivity of the soil in situ were made in May 2018 at 163 points. On average, the value of soil apparent elec-tric conductivity within the investigated polygon was 0.55 dSm/m and varied within 0.17–1.10 dSm/m. Such environment predictors as tree stand density, relief altitude, topographic wetness index, and potential of relief to erosion were able to explain 48% of the observed variability of soil electrical conductivity. The relief altitude had the greatest influence on the variation of soil electrical con-ductivity, which was indicated with the highest values of beta regression coefficients. The most important trend of the electric con-ductivity variation was due to the influence of relief altitude and this dependence was nonlinear. The smallest values of the soil elec-trical conductivity were recorded in the highest and in lowest relief positions, and the largest values were detected in the relief slope. Recreational load can also be explained by the geomorphology predictors and tree stand density data. These predictors can explain 32% of the variation of recreational load. The variogram was built both for the soil apparent electrical conductivity dataset and for the residuals of the regression model. As a result of the procedure of the models’ selection on the basis of the AIC we obtained the best estimation of the variogram models parameters for the electrical conductivity and for the regression residuals of the electrical conduc-ti vity. The level of recreation was correlated statistically significantly with the apparent soil electrical conductivity. The residuals of regression models in which geomorphological indicators and tree stand density were used as predictors have a higher correlation level than the original variables. The soil electrical conductivity may be a sensitive indicator of the recreation loa

Grey and white matter correlates of recent and remote autobiographical memory retrieval:Insights from the dementias

The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events

Способ управления морфологией катодного осадка на основе определения электрохимического сопротивления процесса электроосаждения меди

Проблематика. Актуальною проблемою електроекстракційного отримання компактної міді з гідрометалургійних розчинів є інтенсифікація процесу завдяки підвищенню максимально допустимих робочих густин струму при збереженні високої ефективності процесу. Мета дослідження. Розробка способу визначення максимально допустимих робочих густин струму формування компактних осадів міді для процесу електроекстракції на основі використання залежностей електрохімічного опору (ri) від робочої густини струму (i). Методика реалізації. Застосовувався метод отримання катодних поляризаційних кривих процесу осадження міді із сульфатних розчинів. Морфологію катодної міді, осадженої за умов варіювання концентрації іонів міді, сульфатної кислоти та густини струму, досліджували за допомогою металографічного мікроскопа. Результати дослідження. Показано, що максимальна робоча густина струму осадження компактних осадів міді прийнятної для гідрометалургії якості відповідає початку підйому кривої ri — i після мінімуму. Встановлено, що збільшення концентрації міді зумовлює розширення області мінімуму, а концентрації кислоти – звуження. Аналітично отримано рівняння, яке дає змогу розмежувати міграційну та дифузійну складові граничної густини струму для цієї системи. Висновки. Вперше за допомогою методу диференціювання поляризаційних кривих, з використанням рівняння для умов змішаної кінетики, здійснено визначення максимальної робочої густини струму осадження компактних осадів з врахуванням зміни складу сульфатного розчину електроекстракції міді.Background. The intensification of compact copper electrowinning process based on increasing of maximal permissible working current density is an actual problem. Objective. The aim of this work is the development of method for determining maximal permissible working current density of compact copper deposits based on application of electrochemical resistance (ri) versus working current density (і) dependences. Methods. The method of cathodic polarization curves of copper deposition process with sulfate solutions was used. The morphology of cathodic copper deposits which had obtained under conditions of varying concentrations of copper ions, sulfuric acid, current density, had been studied by metallographic microscope. Results. It was shown that maximal working current density of compact copper deposit formation, with permissible quality for hydrometallurgy, complies with beginning of growing after minimum ri — i curve. It was found that increasing of copper concentration leads to enlargement of minimal ri range, but increasing of acid concentration conversely narrowed this range. The equation which allows dividing of migration and diffusion components of limiting current density for this system was analytically received. Conclusions. The determination of maximal current density of compact deposits formation under conditions of varying sulfate solution composition in copper electrowinning process is carried out for the first time on the basis of differentiation polarization curves method.Проблематика. Актуальной проблемой при электроэкстракционном получении компактной меди из гидрометаллургических растворов является интенсификация процесса путем повышения максимально допустимой рабочей плотности тока при сохранении высокой эффективности процесса. Цель исследования. Разработка способа прогнозирования максимально-допустимых рабочих плотностей тока формирования компактных осадков меди на основе использования зависимостей электрохимического сопротивления (ri) от рабочей плотности тока (i). Методика реализации. Применялся метод получения катодных поляризационных кривых процесса осаждения меди из сульфатных растворов. Морфологию катодной меди, осажденной при условиях варьирования концентрации ионов меди, сульфатной кислоты и плотности тока, исследовали с помощью металлографического микроскопа. Результаты исследования. Показано, что максимальная рабочая плотность тока осаждения компактных осадков меди приемлемого для гидрометаллургии качества соответствует началу подъема кривой ri — i после минимума. Установлено, что увеличение концентрации меди приводит к расширению области минимума, а концентрации кислоты – к сужению. Аналитически получено уравнение, которое позволяет разграничить миграционную и диффузионную составляющие предельной плотности тока для данной системы. Выводы. Впервые с помощью метода дифференцирования поляризационных кривых, с использованием уравнения для условий смешанной кинетики, осуществлено определение максимальной рабочей плотности тока осаждения компактных осадков с учетом изменения состава сульфатного раствора электроэкстракции меди

РОЛЬ ГЕНОВ RLM И AVRLM В РЕАЛИЗАЦИИ СПЕЦИФИЧЕСКОЙ УСТОЙЧИВОСТИ К ФОМОЗУ У РАПСА

As part of the study, DNA markers for local races L. maculans were identified and found that the AvrLm4-7 sequence in the selected fungus population is specifically recognized by the resistance Rlm4 and Rlm7 genes. The SCAR marker BN204 was identified, which allows us to identify homozygous and heterozygous plants carrying the Rlm4 gene. The work collection, including 22 varieties and 39 hybrids of rape, was analyzed using the DNA marker BN204. PCR results allowed us to establish that the number of individual plants with the resistance Rlm4 gene was higher than the number of stable forms characterized by the infection of leaf explants with pathogen races carrying the AvrLm4-7 sequence. It is supposed that these individual plants contain the Rlm4 gene, but they lack the Rlm7 gene.В ходе исследования выявлены ДНК-маркеры к местным расам L. maculans и установлено, что в популяции отобранного гриба присутствует последовательность AvrLm4-7, которая специфично распознается генами устойчивости Rlm4 и Rlm7. Выявлен SCAR-маркер BN204, позволяющий идентифицировать гомозиготные и гетерозиготные растения, несущие ген Rlm4. С использованием ДНК-маркера BN204 была проанализирована рабочая коллекция, включающая 22 сорта и 39 сортообразцов рапса. Результаты ПЦР позволили установить, что количество индивидуальных растений с геном устойчивости Rlm4 было выше, чем количество устойчивых форм, охарактеризованных путем заражения листовых эксплантов расами патогена, несущими последовательность AvrLm4-7. Предполагается, что данные индивидуальные растения содержат ген Rlm4, однако у них отсутствует ген Rlm7.

Chemical interaction, interfacial effect and the microstructural characterization of the induced zinc–aluminum–Solanum tuberosum in chloride solution on mild steel

In this study, we report the effect of Solanum tuberosum (ST) as a strong additive on the morphological interaction, wear, and hardness properties of electroplated zinc coating in chloride bath solutions. The structural and the mechanical behavior of the Zn–Al–ST coating were studied and compared with the properties of Zn coatings. Characterization of the electrodeposited coatings were carried out using scanning electron microscopy, energy dispersive spectrometer, AFM, and X-ray diffraction techniques. The adhesion between the coatings and substrate was examined mechanically using hardness and wear techniques. From the results, amorphous Zn–Al–ST coatings were effectively obtained by electrodeposition using direct current. The coating morphology was revealed to be reliant on the bath composition containing strong leveling additives. From all indications, ST content contribute to a strong interfacial surface effect leading to crack-free and better morphology, good hardness properties, and improved wear resistance due to the precipitation of Zn2Si and Zn7Al2Si3. Hence, addition of ST is beneficial for the structural strengthening, hardness, and wear resistance properties of such coatings

Disruption of Ant-Aphid Mutualism in Canopy Enhances the Abundance of Beetles on the Forest Floor

Ant-aphid mutualism is known to play a key role in the structure of the arthropod community in the tree canopy, but its possible ecological effects for the forest floor are unknown. We hypothesized that aphids in the canopy can increase the abundance of ants on the forest floor, thus intensifying the impacts of ants on other arthropods on the forest floor. We tested this hypothesis in a deciduous temperate forest in Beijing, China. We excluded the aphid-tending ants Lasius fuliginosus from the canopy using plots of varying sizes, and monitored the change in the abundance of ants and other arthropods on the forest floor in the treated and control plots. We also surveyed the abundance of ants and other arthropods on the forest floor to explore the relationships between ants and other arthropods in the field. Through a three-year experimental study, we found that the exclusion of ants from the canopy significantly decreased the abundance of ants on the forest floor, but increased the abundance of beetles, although the effect was only significant in the large ant-exclusion plot (80*60 m). The field survey showed that the abundance of both beetles and spiders was negatively related to the abundance of ants. These results suggest that aphids located in the tree canopy have indirect negative effects on beetles by enhancing the ant abundance on the forest floor. Considering that most of the beetles in our study are important predators, the ant-aphid mutualism can have further trophic cascading effects on the forest floor food web

Identification and structural analysis of C-terminally truncated collapsin response mediator protein-2 in a murine model of prion diseases

<p>Abstract</p> <p>Background</p> <p>Prion diseases are fatal neurodegenerative disorders that accompany an accumulation of the disease-associated form(s) of prion protein (PrP^Sc) in the central nervous system. The neuropathological changes in the brain begin with focal deposits of PrP^Sc, followed by pathomorphological abnormalities of axon terminal degeneration, synaptic loss, atrophy of dendritic trees, and eventual neuronal cell death in the lesions. However, the underlying molecular basis for these neuropathogenic abnormalities is not fully understood.</p> <p>Results</p> <p>In a proteomic analysis of soluble proteins in the brains of mice challenged intracerebrally with scrapie prion (Obihiro I strain), we found that the amount of the full-length form of collapsin response mediator protein-2 (CRMP-2; 61 kDa) decreased in the late stages of the disease, while the amount of its truncated form (56 kDa) increased to comparable levels observed for the full-length form. Detailed analysis by liquid chromatography-electrospray ionization-tandem mass spectrometry showed that the 56-kDa form (named CRMP-2-ΔC) lacked the sequence from serine⁵¹⁸to the C-terminus, including the C-terminal phosphorylation sites important for the regulation of axonal growth and axon-dendrite specification in developing neurons. The invariable size of the mRNA transcript in Northern blot analysis suggested that the truncation was due to post-translational proteolysis. By overexpression of CRMP-2-ΔC in primary cultured neurons, we observed the augmentation of the development of neurite branch tips to the same levels as for CRMP-2^T514A/T555A, a non-phosphorylated mimic of the full-length protein. This suggests that the increased level of CRMP-2-ΔC in the brain modulates the integrity of neurons, and may be involved in the pathogenesis of the neuronal abnormalities observed in the late stages of the disease.</p> <p>Conclusions</p> <p>We identified the presence of CRMP-2-ΔC in the brain of a murine model of prion disease. Of note, C-terminal truncations of CRMP-2 have been recently observed in models for neurodegenerative disorders such as ischemia, traumatic brain injury, and Wallerian degeneration. While the structural identity of CRMP-2-ΔC in those models remains unknown, the present study should provide clues to the molecular pathology of degenerating neurons in prion diseases in connection with other neurodegenerative disorders.</p

Covalent Aurora A regulation by the metabolic integrator coenzyme A

Aurora A kinase is a master mitotic regulator whose functions are controlled by several regulatory interactions and post-translational modifications. It is frequently dysregulated in cancer, making Aurora A inhibition a very attractive antitumor target. However, recently uncovered links between Aurora A, cellular metabolism and redox regulation are not well understood. In this study, we report a novel mechanism of Aurora A regulation in the cellular response to oxidative stress through CoAlation. A combination of biochemical, biophysical, crystallographic and cell biology approaches revealed a new and, to our knowledge, unique mode of Aurora A inhibition by CoA, involving selective binding of the ADP moiety of CoA to the ATP binding pocket and covalent modification of Cys290 in the activation loop by the thiol group of the pantetheine tail. We provide evidence that covalent CoA modification (CoAlation) of Aurora A is specific, and that it can be induced by oxidative stress in human cells. Oxidising agents, such as diamide, hydrogen peroxide and menadione were found to induce Thr 288 phosphorylation and DTT-dependent dimerization of Aurora A. Moreover, microinjection of CoA into fertilized mouse embryos disrupts bipolar spindle formation and the alignment of chromosomes, consistent with Aurora A inhibition. Altogether, our data reveal CoA as a new, rather selective, inhibitor of Aurora A, which locks this kinase in an inactive state via a “dual anchor” mechanism of inhibition that might also operate in cellular response to oxidative stress. Finally and most importantly, we believe that these novel findings provide a new rationale for developing effective and irreversible inhibitors of Aurora A, and perhaps other protein kinases containing appropriately conserved Cys residues