Mercury in Finnish forest lakes and reservoirs : anthropogenic contribution to the load and accumulation in fish

Yhteenveto: Elohopea Suomen metsäjärvissä ja tekoaltaissa: ihmisen vaikutus kuormitukseen ja pitoisuuksiin kaloissa.

A novel fiber-coated strong base-type anion exchanger with superfast kinetics. Removal and recovery of silver thiosulfate from aqueous solutions

A commercial acrylic fiber with 92% (w/w) acrylonitrile content was partially hydrolyzed converting a fraction of the nitrile (-CN) groups to carboxylic acid (-COOH) groups, to coat the fiber with polyethylenimine (PEI) resin, which was then crosslinked with glutaraldehyde and further quaternized with ethyl chloroacetate to produce a novel strong-base anionic exchanger in the form of fiber. Designated as PAN(QPEI.XG)(Cl-), the fibrous sorbent was compared with a commercial bead-form resin Amberlite IRA-458(Cl-) in respect of sorption capacity, selectivity, and kinetics for removal of silver thiosulfate complexes from aqueous solutions. Though the saturation level of [Ag(S2O3)(2)](3-) on PAN(QPEI.XG)(Cl-) is considerably less than that on IRA-458(Cl-), the gel-coated fibrous sorbent exhibits, as compared to the bead-form sorbent, a significantly higher sorption selectivity for the silver thiosulfate complex in the presence of excess of other anions Such as S2O32-, SO42-, and Cl-, and a remarkably faster rate of both sorption and stripping. The initial uptake of the sorbate by the fibrous sorbent is nearly instantaneous, reaching up to similar to 80% of the saturation capacity within 10 s, as compared to only similar to 12% on the bead-form sorbent. The high initial rate of uptake fits a shell-core kinetic model for sorption on fiber of cylindrical geometry. With 4M HCl, the stripping of the sorbed silver complex from the fibrous sorbent is clean and nearly instantaneous, while, in contrast, a much slower rate of stripping on the bead-form sorbent leads to its fouling due to a slow decomposition of the silver thiosulfate complex in the acidic medium.

Myotonic dystrophy type 2 (DM2) : Diagnostic methods and molecular pathology

Myotonic dystrophies type 1 (DM1) and type 2 (DM2) are the most common forms of muscular dystrophy affecting adults. They are autosomal dominant diseases caused by microsatellite tri- or tetranucleotide repeat expansion mutations in transcribed but not translated gene regions. The mutant RNA accumulates in nuclei disturbing the expression of several genes. The more recently identified DM2 disease is less well known, yet more than 300 patients have been confirmed in Finland thus far, and the true number is believed to be much higher. DM1 and DM2 share some features in general clinical presentation and molecular pathology, yet they show distinctive differences, including disease severity and differential muscle and fiber type involvement. However, the molecular differences underlying DM1 and DM2 muscle pathology are not well understood. Although the primary tissue affected is muscle, both DMs show a multisystemic phenotype due to wide expression of the mutation-carrying genes. DM2 is particularly intriguing, as it shows an incredibly wide spectrum of clinical manifestations. For this reason, it constitutes a real diagnostic challenge. The core symptoms in DM2 include proximal muscle weakness, muscle pain, myotonia, cataracts, cardiac conduction defects and endocrinological disturbations; however, none of these is mandatory for the disease. Myalgic pains may be the most disabling symptom for decades, sometimes leading to incapacity for work. In addition, DM2 may cause major socio-economical consequences for the patient, if not diagnosed, due to misunderstanding and false stigmatization. In this thesis work, we have (I) improved DM2 differential diagnostics based on muscle biopsy, and (II) described abnormalities in mRNA and protein expression in DM1 and DM2 patient skeletal muscles, showing partial differences between the two diseases, which may contribute to muscle pathology in these diseases. This is the first description of histopathological differences between DM1 and DM2, which can be used in differential diagnostics. Two novel high-resolution applications of in situ -hybridization have been described, which can be used for direct visualization of the DM2 mutation in muscle biopsy sections, or mutation size determination on extended DNA-fibers. By measuring protein and mRNA expression in the samples, differential changes in expression patterns affecting contractile proteins, other structural proteins and calcium handling proteins in DM2 compared to DM1 were found. The dysregulation at mRNA level was caused by altered transciption and abnormal splicing. The findings reported here indicate that the extent of aberrant splicing is higher in DM2 compared to DM1. In addition, the described abnormalities to some extent correlate to the differences in fiber type involvement in the two disorders.

Interaction between the Z-type DNA duplex and 1,3-propanediamine:crystal structure of d(CACGTG)(2) at 1.2 angstrom resolution

The crystal structure of a hexamer duplex d(CACGTG)(2) has been determined and refined to an R-factor of 18.3% using X-ray data up to 1.2 angstrom resolution. The sequence crystallizes as a left-handed Z-form double helix with Watson-Crick base pairing. There is one hexamer duplex, a spermine molecule, 71 water molecules, and an unexpected diamine (Z-5, 1,3-propanediamine, C3H10N2)) in the asymmetric unit. This is the high-resolution non-disordered structure of a Z-DNA hexamer containing two AT base pairs in the interior of a duplex with no modifications such as bromination or methylation on cytosine bases. This structure does not possess multivalent cations such as cobalt hexaammine that are known to stabilize Z-DNA. The overall duplex structure and its crystal interactions are similar to those of the pure-spermine form of the d(CGCGCG)(2) structure. The spine of hydration in the minor groove is intact except in the vicinity of the T5A8 base pair. The binding of the Z-5 molecule in the minor grove of the d(CACGTG)(2) duplex appears to have a profound effect in conferring stability to a Z-DNA conformation via electrostatic complementarity and hydrogen bonding interactions. The successive base stacking geometry in d(CACGTG)(2) is similar to the corresponding steps in d(CG)(3). These results suggest that specific polyamines such as Z-5 could serve as powerful inducers of Z-type conformation in unmodified DNA sequences with AT base pairs. This structure provides a molecular basis for stabilizing AT base pairs incorporated into an alternating d(CG) sequence.

Studies on electrical switching behavior of As-Te-Tl glasses - effect of local structure on switching type and composition dependence of switching voltages

Bulk As-Te-Tl glasses belonging to the As30Te70-xTlx (4 <= x <= 22) and As40Te60-xTlx (5 <= x <= 20) composition tie lines are studied for their I-V characteristics. Unlike other As-Te-III glasses such as As-Te-Al and As-Te-In, which exhibit threshold behavior, the present samples show memory switching. The composition dependence of switching voltages (V-t) of As-Te-Tl glasses is also different from that of As-Te-Al and As-Te-In glasses, and it is found that V-t decreases with the addition of Tl. Both the type of switching exhibited by As-Te-Tl glasses and the composition dependence of V-t, seems to be intimately connected with the nature of bonding of Tl atoms and the resultant structural network. Furthermore, the temperature and thickness dependence of switching voltages of As-Te-Tl glasses suggest an electro thermal mechanism for switching in these samples.

Reducing the babel in plant volatile communication: using the forest to see the trees

While plants of a single species emit a diversity of volatile organic compounds (VOCs) to attract or repel interacting organisms, these specific messages may be lost in the midst of the hundreds of VOCs produced by sympatric plants of different species, many of which may have no signal content. Receivers must be able to reduce the babel or noise in these VOCs in order to correctly identify the message. For chemical ecologists faced with vast amounts of data on volatile signatures of plants in different ecological contexts, it is imperative to employ accurate methods of classifying messages, so that suitable bioassays may then be designed to understand message content. We demonstrate the utility of `Random Forests' (RF), a machine-learning algorithm, for the task of classifying volatile signatures and choosing the minimum set of volatiles for accurate discrimination, using datam from sympatric Ficus species as a case study. We demonstrate the advantages of RF over conventional classification methods such as principal component analysis (PCA), as well as data-mining algorithms such as support vector machines (SVM), diagonal linear discriminant analysis (DLDA) and k-nearest neighbour (KNN) analysis. We show why a tree-building method such as RF, which is increasingly being used by the bioinformatics, food technology and medical community, is particularly advantageous for the study of plant communication using volatiles, dealing, as it must, with abundant noise.

Supramolecular insulin assembly II for a sustained treatment of type 1 diabetes mellitus

Diabetes is a chronic disease requiring continuous medical supervision and patient education to prevent acute secondary complications. In this study, we have harnessed the inherent property of insulin to aggregate into an oligomeric intermediate on the pathway to amyloid formation, to generate a form that exhibits controlled and sustained release for extended periods. Administration of a single dose of the insulin oligomer, defined here as the supramolecular insulin assembly II (SIA-II), to experimental animals rendered diabetic by streptozotocin or alloxan, released the hormone capable of maintaining physiologic glucose levels for > 120 days for bovine and > 140 days for recombinant human insulin without fasting hypoglycemia. Moreover, the novel SIA-II described here not only improved the glycemic control, but also reduced the extent of secondary diabetic complications.

Forest governance and climate change adaptation : Case studies of four African countries

Africa is threatened by climate change. The adaptive capacity of local communities continues to be weakened by ineffective and inefficient livelihood strategies and inappropriate development interventions. One of the greatest challenges for climate change adaptation in Africa is related to the governance of natural resources used by vulnerable poor groups as assets for adaptation. Practical and good governance activities for adaptation in Africa is urgently and much needed to support adaptation actions, interventions and planning. The adaptation role of forests has not been as prominent in the international discourse and actions as their mitigation role. This study therefore focused on the forest as one of the natural resources used for adaptation. The general objective of this research was to assess the extent to which cases of current forest governance practices in four African countries Burkina Faso, The Democratic Republic of Congo (DRC), Ghana and Sudan are supportive to the adaptation of vulnerable societies and ecosystems to impacts of climate change. Qualitative and quantitative analyses from surveys, expert consultations and group discussions were used in analysing the case studies. The entire research was guided by three conceptual sets of thinking forest governance, climate change vulnerability and ecosystem services. Data for the research were collected from selected ongoing forestry activities and programmes. The study mainly dealt with forest management policies and practices that can improve the adaptation of forest ecosystems (Study I) and the adaptive capacity through the management of forest resources by vulnerable farmers (Studies II, III, IV and V). It was found that adaptation is not part of current forest policies, but, instead, policies contain elements of risk management practices, which are also relevant to the adaptation of forest ecosystems. These practices include, among others, the management of forest fires, forest genetic resources, non-timber resources and silvicultural practices. Better livelihood opportunities emerged as the priority for the farmers. These vulnerable farmers had different forms of forest management. They have a wide range of experience and practical knowledge relevant to ensure and achieve livelihood improvement alongside sustainable management and good governance of natural resources. The contributions of traded non-timber forest products to climate change adaptation appear limited for local communities, based on their distribution among the stakeholders in the market chain. Plantation (agro)forestry, if well implemented and managed by communities, has a high potential in reducing socio-ecological vulnerability by increasing the food production and restocking degraded forest lands. Integration of legal arrangements with continuous monitoring, evaluation and improvement may drive this activity to support short, medium and long term expectations related to adaptation processes. The study concludes that effective forest governance initiatives led by vulnerable poor groups represent one practical way to improve the adaptive capacities of socio-ecological systems against the impacts of climate change in Africa.

High-temperature superconductivity in bismuth-copper oxides of the type BimMnCupOx (M=Mg, Ca, Sr, Ba, Bi)

Several oxides of the Bi m M n Cu p O x family (m=2, 3;n=2, 3, 4;p=1, 2, 3 and M=alkaline earth or Bi), possessing structures similar to the Aurivillius family of oxides, show highT c superconductivity.

Hot gaseous coronae of early-type galaxies and their radio luminosity function

Recent X-ray observations have revealed that early-type galaxies (which usually produce extended double radio sources) generally have hot gaseous haloes extending up to approx102kpc1,2. Moreover, much of the cosmic X-ray background radiation is probably due to a hotter, but extremely tenuous, intergalactic medium (IGM)3. We have presented4–7 an analytical model for the propagation of relativistic beams from galactic nuclei, in which the beams' crossing of the pressure-matched interface between the IGM and the gaseous halo, plays an important role. The hotspots at the ends of the beams fade quickly when their advance becomes subsonic with respect to the IGM. This model has successfully predicted (for typical double radio sources) the observed8 current mean linear-size (approx2Dsime350 kpc)4,5, the observed8–11 decrease in linear-size with cosmological redshift4–6 and the slope of the linear-size versus radio luminosity10,12–14 relation6. We have also been able to predict the redshift-dependence of observed numbers and radio luminosities of giant radio galaxies7,15. Here, we extend this model to include the propagation of somewhat weaker beams. We show that the observed flattening of the local radio luminosity function (LRLF)16–20 for radio luminosity Papproximately 1024 W Hz-1 at 1 GHz can be explained without invoking ad hoc a corresponding break in the beam power function Phi(Lb), because the heads of the beams with Lb < 1025 W Hz-1 are decelerated to sonic velocity within the halo itself, which leads to a rapid decay of radio luminosity and a reduced contribution of these intrinsically weaker sources to the observed LRLF.

Diabetic cardiomyopathy and post-infarct ventricular remodelling : Effects of levosimendan in a rodent model of type II diabetes

Type 2 diabetes is a risk factor for the development of cardiovascular disease. Recently, the term diabetic cardiomyopathy has been proposed to describe the changes in the heart that occur in response to chronic hyperglycemia and insulin resistance. Ventricular remodelling in diabetic cardiomyopathy includes left ventricular hypertrophy, increased interstitial fibrosis, apoptosis and diastolic dysfunction. Mechanisms behind these changes are increased oxidative stress and renin-angiotensin system activation. The diabetic Goto-Kakizaki rat is a non-obese model of type 2 diabetes that exhibits defective insulin signalling. Recently two interconnected stress response pathways have been discovered that link insulin signalling, longevity, apoptosis and cardiomyocyte hypertrophy. The insulin-receptor PI3K/Ak pathway inhibits proapoptotic FOXO3a in response to insulin signalling and the nuclear Sirt1 deacetylase inhibits proapoptotic p53 and modulates FOXO3a in favour of survival and growth. --- Levosimendan is a calcium sensitizing agent used for the management of acute decompensated heart failure. Levosimendan acts as a positive inotrope by sensitizing cardiac troponin C to calcium and exerts vasodilation by opening mitochondrial and sarcolemmal ATP-sensitive potassium channels. Levosimendan has been described to have beneficial effects in ventricular remodelling after myocardial infarction. The aims of the study were to characterize whether diabetic cardiomyopathy associates with cardiac dysfunction, cardiomyocyte apoptosis, hypertrophy and fibrosis in spontaneously diabetic Goto-Kakizaki (GK) rats, which were used to model type 2 diabetes. Protein expression and activation of the Akt FOXO3a and Sirt1 p53 pathways were examined in the development of ventricular remodelling in GK rats with and without myocardial infarction (MI). The third and fourth studies examined the effects of levosimendan on ventricular remodelling and gene expression in post-MI GK rats. The results demonstrated that diabetic GK rats develop both modest hypertension and features similar to diabetic cardiomyopathy including cardiac dysfunction, LV hypertrophy and fibrosis and increased apoptotic signalling. MI induced a sustained increase in cardiomyocyte apoptosis in GK rats together with aggravated LV hypertrophy and fibrosis. The GK rat myocardium exhibited decreased Akt- FOXO3a phosphorylation and increased nuclear translocation of FOXO3a and overproduction of the Sirt1 protein. Treatment with levosimendan decreased cardiomyocyte apoptosis, senescence and LV hypertrophy and altered the gene expression profile in GK rat myocardium. The findings indicate that impaired cardioprotection via Akt FOXO3a and p38 MAPK is associated with increased apoptosis, whereas Sirt1 functions in counteracting apoptosis and the development of LV hypertrophy in the GK rat myocardium. Overall, levosimendan treatment protects against post-MI ventricular remodelling and alters the gene expression profile in the GK rat myocardium.

Markov random fields and spatial smoothing in improving of forest inventory estimates

Markov random fields (MRF) are popular in image processing applications to describe spatial dependencies between image units. Here, we take a look at the theory and the models of MRFs with an application to improve forest inventory estimates. Typically, autocorrelation between study units is a nuisance in statistical inference, but we take an advantage of the dependencies to smooth noisy measurements by borrowing information from the neighbouring units. We build a stochastic spatial model, which we estimate with a Markov chain Monte Carlo simulation method. The smooth values are validated against another data set increasing our confidence that the estimates are more accurate than the originals.

Low-temperature synthesis of novel layered alkali metal-MoO3 bronzes and hexagonal bronzes of the type KyW1−xMoxO3

A new class of layered alkali metal-MoO3 bronzes,AxMoO3 (A =Li, Na, K, Rb), with nearly the same unit cell parameters as the host oxide has been synthesized by the solid-state reaction of MoO3 with alkali metal iodides around 575 K; LixMoO3 absorbs H2O causing an increase in theb parameter of the unit cell. Hexagonal potassium bronzes of W1−xMoxO3 are synthesized for the first time.