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Timescales of interface-coupled dissolution-precipitation reactions oncarbonates

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Geoscience Frontiers 2019年第1期10卷 17-27页

作者： Francois Renard anja Royne Christine V.Putnis The Njord Centre Physics of Geological Processes Departments of Geoscience and Physics University of Oslo Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS Institut für Mineralogie University of Münster The Institute for Geoscience Research (TIGeR) Department of Chemistry Curtin University

In the Earth's upper crust, where aqueous fluids can circulate freely, most mineral transformations are controlled by the coupling between the dissolution of a mineral that releases chemical species into the fluid and precipitation of new minerals that contain some of the released species in their crystal structure, the coupled process being driven by a reduction of the total free-energy of the system. Such coupled dissolution-precipitation processes occur at the fluid-mineral interface where the chemical gradients are highest and heterogeneous nucleation can be promoted, therefore controlling the growth kinetics of the new minerals. Time-lapse nanoscale imaging using Atomic Force Microscopy(AFM) can monitor the whole coupled process under in situ conditions and allow identifying the time scales involved and the controlling parameters. We have performed a series of experiments on carbonate minerals(calcite, siderite, dolomite and magnesite) where dissolution of the carbonate and precipitation of a new mineral was imaged and followed through time. In the presence of various species in the reacting fluid(e. g. antimony, selenium, arsenic, phosphate), the calcium released during calcite dissolution binds with these species to form new minerals that sequester these hazardous species in the form of a stable solid phase. For siderite, the coupling involves the release of Fe^(2+) ions that subsequently become oxidized and then precipitate in the form of FeIIIoxyhydroxides. For dolomite and magnesite,dissolution in the presence of pure water(undersaturated with any possible phase) results in the immediate precipitation of hydrated Mg-carbonate phases. In all these systems, dissolution and precipitation are coupled and occur directly in a boundary layer at the carbonate surface. Scaling arguments demonstrate that the thickness of this boundary layer is controlled by the rate of carbonate dissolution,the equilibrium concentration of the precipitates and the kinetics of diffus

关键词： Carbonates Atomic force microscopy Dissolution Precipitation Boundary layer Replacement

Impact of crystalline and amorphous iron-and aluminum hydroxides on mechanisms of phosphate adsorption and desorption

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Journal of Environmental Sciences 2018年第8期30卷 175-189页

作者： Stella Gypser Florian Hirsch anja M.Schleicher Dirk Freese Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Soil Protection and Recultivation Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Geopedology and Landscape Development German Research Centre for Geosciences Section 3.1 Inorganic and Isotope Geochchemistry

Fourier-transform infrared（FT-IR） spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron–aluminum–hydroxide mixtures in the molar ratio 1：0, 10：1, 5：1, 1：1, 1：5, 1：10 and 0：1. The OH stretching vibrational bands were utilized to analyze changes in structural and surface OH groups during adsorption, because the position of characteristic P／O vibrational bands can shift depending on reaction conditions, pH or adsorbed phosphate *** and desorption kinetics were studied at pH6 and different initial phosphate concentrations to achieve varying phosphate coverage on the mineral surfaces. For gibbsite the formation of AlHPO4 and Al2HPO4 can be assumed, while for ferrihydrite, a FeHPO4 or Fe2PO4 complex and the precipitation of FePO4 with longer equilibration time were ***2HPO4 or a Fe2PO4 surface complex was deduced for Fe-hydroxides, an AlH2PO4 surface complex was identified for Al-hydroxide, and both displayed either hydrogen bonds to neighboring hydroxyl groups or hydrogen bonds to outer-sphere complexes. Fe：Al-hydroxide mixtures with high Al ratios showed a low phosphate desorption rate, while ferrihydrite and the Fe：Al-hydroxide mixtures with high Fe ratios had almost negligible desorption rates. It was concluded that within the weakly associated amorphous FeO（OH） materials, FePO4 precipitated, which was bound by outer-sphere hydrogen bonds. With high Al ratios, desorption increased, which indicated weaker phosphate binding of both inner-sphere and outer-sphere complexes and hence, either no or minor quantities of precipitate. Ferrihydrite showed a more rigid structure and a lower extent of precipitation compared to amorphous Fe-hydroxide.

关键词： Phosphate Adsorption Desorption Surface complexation Precipitation FT-IR

Electrochemical inactivation of cyanobacteria and microcystin degradation using a boron-doped diamond anode-A potential tool for cyanobacterial bloom control

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Journal of Environmental Sciences 2017年第3期29卷 248-261页

作者： Andrej Meglic anja Pecman Tinkara Rozina Domen Lestan Bojan Sedmak Arhel Ltd. Pustourhoua c.63SI-1000 LjubljanaSlovenia Centre for Soil and Environmental Sciences Biotechnical FacultyUniversity of LjubljanaJamnikarjeva 101SI-1000 LjubljanaSlovenia Envit Ltd. Vojkova c.63SI-1000 LjubljanaSlovenia Department of Genetic Toxicology and Cancer Biology National Institute of BiologyVecna pot 111SI-1000 LjubljanaSlovenia

Cyanobacterial blooms are global phenomena that can occur in calm and nutrient-rich （eutrophic） fresh and marine waters. Human exposure to cyanobacteria and their biologically active products is possible during water sports and various water activities, or by ingestion of contaminated water. Although the vast majority of harmful cyanobacterial products are confined to the interior of the cells, these are eventually released into the surrounding water following natural or artificially induced cell death. Electrochemical oxidation has been used here to damage cyanobacteria to halt their proliferation, and for microcystin degradation under in-vitro conditions. Partially spent Jaworski growth medium with no addition of supporting electrolytes was used. Electrochemical treatment resulted in the cyanobacterial loss of cell-buoyancy regulation, cell proliferation arrest, and eventual cell death. Microcystin degradation was studied separately in two basic modes of treatment： batch-wise flow, and constant flow, for electrolytic-cell exposure. Batch-wise exposure simulates treatment under environmental conditions, while constant flow is more appropriate for the study of boron-doped diamond electrode efficacy under laboratory conditions. The effectiveness of microcystin degradation was established using high-performance liquid chromatography-photodiode array detector analysis, while the biological activities of the products were estimated using a colorimetric protein phosphatase-1 inhibition assay. The results indicate potential for the application of electro-oxidation methods for the control of bloom events by taking advantage of specific intrinsic ecological characteristics of bloom-forming cyanobacteria. The applicability of the use of boron-doped diamond electrodes in remediation of water exposed to cyanobacteria bloom events is discussed.

关键词： Cyanobacterial bloom controlBoron-doped diamond anodeElectro-oxidationMicrocystin degradationProtein phosphatase-1 inhibitionWater remediation

Psychosocial factors affecting the etiology and management of type 1 diabetes mellitus:A narrative review

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World Journal of Diabetes 2021年第9期12卷 1518-1529页

作者： anja Turin Maja DrobničRadobuljac Department for Child Psychiatry University Children’s HospitalUniversity Medical Centre LjubljanaLjubljana 1000Slovenia Department of Psychiatry Faculty of MedicineUniversity of LjubljanaLjubljana 1000Slovenia

Type 1 diabetes(T1D)is one of the most common chronic diseases in children and adolescents *** etiopathogenesis results from the interplay of genetic and environmental *** the latter,psychological stress has been implicated in disease onset as well as disease *** studies,including large population-based studies,have highlighted the role of stressful life events in the etiopathogenesis of *** this article,we also emphasize the importance of attachment in the early child-caregiver relationship,which can be seen as a measure of the quality of the relationship and is crucial for stress and emotional *** serves as a model for all subsequent relationships in one’s *** summarize some of the few studies performed in the field of attachment and T1D etiopathogenesis or management.T1D management demands a lifelong therapeutic regimen to prevent acute and chronic *** addition to psychological stress,psychological factors such as family functioning,developmental adjustment,autonomy,mental health problems and other factors have been found to relate to metabolic *** factors need to be understood not as a single directional causality-based principle but as a dynamic bi-or multidirectional system that is affected by the normal developmental transitions of childhood and adolescence.

关键词： Type 1 diabetes Psychosocial factors Stressful life events Etiology Disease management Attachment

A critical review on natural compounds interacting with the plant plasma membrane H^(+)-ATPase and their potential as biologicals in agriculture

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Journal of Integrative Plant Biology 2022年第2期64卷 268-286页

作者： Nanna W.Havshφi anja T.Fuglsang Department of Plant and Environmental Sciences Section for Transport BiologyUniversity of CopenhagenFrederiksbergCopenhagenDK-1871 Denmark

The plant plasma membrane(PM)H^(+)-ATPase is an essential enzyme controlling plant growth and *** is an important factor in response to abiotic and biotic stresses and is subject to tight *** are in demand for new sustainable natural growth regulators and as a key enzyme for regulation of transport into the plant cell the PM H^(+)-ATPase is a potential target for *** this review,we have evaluated the known non-protein natural compounds with regulatory effects on the PM H^(+)-ATPase,focusing on their mechanism of action and their potential as biologicals/growth regulators in plant production of future sustainable agriculture.

关键词： biologicals cyclic-lipodepsipeptides H^(+)-ATPase H+pump natural compounds phosphatidylinositol plasma membrane pore forming compound tenuazonic acid

Failure of a T cell regulator: CD6 contributes to the aggravation of autoimmune inflammation

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Cellular & Molecular Immunology 2019年第9期16卷 733-734页

作者： anja Meyer David M.Kofler Division of Clinical Immunology and Rheumatology Department I of Internal MedicineUniversity of CologneCologne 50937Germany

The scavenger-like lymphocyte receptor CD6 is a regulator of T cell functions,and is associated with autoimmune ***,the specific contribution of CD6 to autoimmunity remains *** physiological conditions,CD6 associates with the T cell antigen receptor(TCR)/CD3 complex at the center of the immunological synapse and regulates T cell responses through activation-dependent recruitment of the positive regulator SLP-76 and other downstream signaling effectors.1,2 In recent years,immune-activating and immune-inhibiting functions of CD6 have been reported,indicating a dual role of CD6 in T cell activation.1 It has been postulated that the strength of TCR activation determines whether CD6 enhances or inhibits TCR signaling.1 This possible counter-regulatory role of CD6 may contribute to the control of T cell responses.

关键词： autoimmune inflammation CD6

Dual Targeting of a Mitochondrial Protein： The Case Study of Cytochrome C1

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Molecular Plant 2011年第4期4卷 679-687页

作者： anja Rodiger Bianca Baudisch Uwe Langner Ralf Bernd Klosgen Institute of Biology--Plant Physiology Martin Luther University Halle-Wittenberg Weinbergweg 10 06120 Halle/Saale Germany

As a result of the endosymbiotic gene transfer, the majority of proteins of mitochondria and chloroplasts is encoded in the nucleus and synthesized in the cytosol as precursor molecules carrying N-terminal transit peptides for the transport into the respective target organelle. In most instances, transport takes place into either mitochondria or chloroplasts, although a few examples of dual targeting into both organelles have been described. Here, we show by a combination of three different experimental strategies that also cytochrome c1 of potato, a component of the respiratory electron transport chain, is imported not only into mitochondria, but also into plastids. In organello import experiments with isolated mitochondria and chloroplasts, which were analyzed in both single and mixed organelte assays, demonstrate that the processing products accumulating after import within the two endosymbiotic organelles are different in size. Dual targeting of cytochrome c1 is observed also in vivo, after biolistic transformation of leaf epidermal cells with suitable reporter constructions. Finally, Western analyses employing cytochrome c1-specific antiserum provide evidence that the protein accumulates in significant amounts in mitochondria and chloroplasts of both pea and spinach. The possible consequences of our findings on the relevance of the dual targeting phenomenon are discussed.

关键词： Protein transport dual targeting cytochrome c1 mitochondria chloroplast.

Precise orbit determination for a large LEO constellation with inter-satellite links and the measurements from different ground networks:a simulation study

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Satellite Navigation 2022年第3期3卷 38-50,I0002页

作者： Xingchi He Urs Hugentobler anja Schlicht Yufeng Nie Bingbing Duan Institute for Astronomical and Physical Geodesy Technical University of MunichArcisstr.2180333MunichGermany College of Surveying and Geo-Informatics Tongji UniversitySiping Road 1239Shanghai200092China

Geodetic applications of Low Earth Orbit(LEO)satellites requires accurate satellite *** of using onboard Global Navigation Satellite System observations,this contribution treats the LEO satellite constellation independently,using Inter-Satellite Links and the measurements of different ground *** to geopolitical and geographical reasons,a ground station network cannot be well *** compute the impact of different ground networks(i.e.,global networks with different numbers of stations and regional networks in different areas and latitudes)on LEO satellite orbit determination with and without the inter-satellite *** results are based on a simulated constellation of 90 LEO *** find that the orbits determined using a high latitude network is worse than using a middle or low latitude *** is because the high latitude network has a poorer geometry even if the availability of satellite measurements is higher than for the other two ***,adding more stations in a regional network shows almost no improvements on the satellite orbits if the number of stations is more than *** the help of ISL observations,however,the satellite orbits determined with a small regional network can reach the same accuracy as that with the global network of 60 ***,satellite biases can be well estimated(less than 0.6 mm)and have nearly no impact on satellite *** does thus not matter if they are not physically calibrated for estimating precise orbits.

关键词： LEO satellite Orbit determination Ground station distribution Inter-satellite link

Helicobacter pylori virulence genes

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World Journal of Gastroenterology 2019年第33期25卷 4870-4884页

作者： anja Sterbenc Erika Jarc Mario Poljak Matjaz Homan Institute of Microbiology and Immunology Faculty of MedicineUniversity of LjubljanaLjubljana 1000Slovenia Department of Gastroenterology Hepatology and NutritionUniversity Children’s HospitalFaculty of MedicineUniversity of LjubljanaLjubljana 1000Slovenia

Helicobacter pylori(***)is one of the most important human pathogens,infecting approximately half of the global *** its high prevalence,only a subset of *** infected individuals develop serious gastroduodenal *** pathogenesis of *** infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence *** has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial *** virulence factors enable successful colonization of the gastric mucosa and sustain persistent *** infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric *** studies have focused on the prevalence and role of putative *** virulence genes in disease *** several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study *** review presents key findings on the most important *** virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.

关键词： Helicobacter pylori Virulence genes Disease association Children Adults Outer membrane proteins Bacterial toxins