CHIRONOMID FAUNA OF CENTRAL YAKUTIAN LAKES (NORTHERN RUSSIA) IN PALAEOENVIRONMENTAL INVESTIGATION

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CHIRONOMID FAUNA OF CENTRAL YAKUTIAN LAKES (NORTHERN RUSSIA) IN PALAEOENVIRONMENTAL INVESTIGATION

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Limnological characteristics of lakes in the lowlands of Central Yakutia, Russia

The physico-chemical characteristics of 47 lakes from two regions in the lowlands of Central Yakutia (Vilyuysk and Yakutsk), Eastern Siberia were analysed. The aims of this study were (i) to classify the lakes according to their ionic compositions and their nutrient concentrations, (ii) to quantify environmental gradients representing the main directions of variation in the measured variables, and (iii) to explore the relationship between the investigated lakes and their spatial positions. Most of the study lakes are shallow, thermokarst lakes that are slightly alkaline to alkaline. The lakes are predominantly oligotrophic, with some mesotrophic and a few eutrophic exceptions in the study region Vilyuysk. There are four hypertrophic lakes in the study region Yakutsk which are strongly affected by anthropogenic inputs and, in one case, additionally by inputs of water birds. Most part of the variance in the data is represented by major ion concentrations and related variables such as electrical conductivity. There were clear differences in these variables between the lakes of both study regions partly due to regional differences in the climate-induced negative water balance (i.e. evaporation exceeds precipitation). The statistical analysis has shown that a significant part of the variance can be attributed to the type of vegetation in the lake's catchment (11%), to the longitude (7.6%) and to local spatial differences in the lake water chemistry (2.8%). Hypothesis testing indicated that there are significant differences in the mean values of many variables according to vegetation type and to the region where the lakes are located. However, the hypothesis of spatial autocorrelation in the data had to be rejected. The results presented here have important implications for ongoing and future limnological and paleoenvironmental studies in Yakutia. The exploratory analysis has shown that the physico-chemical characteristics of Central Yakutian lakes are mainly influenced by vegetation and climate driven changes that provides the basis for paleoenvironmental studies

Rapid Synthesis of Sub-10 nm Hexagonal NaYF4-Based Upconverting Nanoparticles using Therminol® 66

We report a simple one-pot method for the rapid preparation of sub-10 nm pure hexagonal (β-phase) NaYF4-based upconverting nanoparticles (UCNPs). Using Therminol® 66 as a co-solvent, monodisperse UCNPs could be obtained in unusually short reaction times. By varying the reaction time and reaction temperature, it was possible to control precisely the particle size and crystalline phase of the UCNPs. The upconversion (UC) luminescence properties of the nanocrystals were tuned by varying the concentrations of the dopants (Nd3+ and Yb3+ sensitizer ions and Er3+ activator ions). The size and phase-purity of the as-synthesized core and core–shell nanocrystals were assessed by using complementary transmission electron microscopy, dynamic light scattering, X-ray diffraction, and small-angle X-ray scattering studies. In-depth photophysical evaluation of the UCNPs was pursued by using steady-state and time-resolved luminescence spectroscopy. An enhancement in the UC intensity was observed if the nanocrystals, doped with optimized concentrations of lanthanide sensitizer/activator ions, were further coated with an inert/active shell. This was attributed to the suppression of surface-related luminescence quenching effects

Holocentric Chromosomes of Luzula elegans Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

The structure of holocentric chromosomes was analyzed in mitotic cells of Luzula elegans. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-negative. During metaphase to anaphase transition, L. elegans chromosomes typically curved to a sickle-like shape, a process that is likely to be influenced by the pulling forces of microtubules along the holocentric axis towards the corresponding microtubule organizing regions. A single pair of 45S rDNA sites, situated distal to Arabidopsis-telomere repeats, was observed at the terminal region of one chromosome pair. We suggest that the 45S rDNA position in distal centromere-free regions could be required to ensure chromosome stability. Copyright (C) 2011 S. Karger AG, Base

Clinical, Ultrasound, and Predictability Outcomes Following Certolizumab Pegol Treatment (with Methotrexate) in Patients with Moderate-to-Severe Rheumatoid Arthritis : 52-Week Results from the CZP-SPEED Study

Introduction: To assess the impact of certolizumab pegol (CZP) treatment on clinical, patient-reported, and musculoskeletal ultrasound outcomes and to determine the treatment response time point most predictive of long-term outcomes in Italian patients with rheumatoid arthritis (RA). Methods: CZP-SPEED (NCT01443364) was a 52-week, open-label, prospective, interventional, multicenter study. Biologic-na\uefve patients with moderate-to-severe active RA, who had failed at least one DMARD treatment, received CZP (400\ua0mg at weeks 0, 2, and 4, then 200\ua0mg every 2\ua0weeks) concomitantly with methotrexate. The primary objective was to identify the time point of clinical response decrease in 28-joint Disease Activity Score [DAS28(ESR)] 65 1.2 most predictive of a clinical response at week 52. Additional clinical and patient-reported outcomes were measured. Power Doppler (PD) ultrasound was used to assess synovial effusion, synovial proliferation, PD signal, cartilage damage, and bone erosion according to international guidelines. Results: A total of 132 patients were enrolled and received CZP; 91/132 (69%) completed to week 52. Predicted 52-week responses for early responders (week 2 onwards) were between 65% and 70%. Rapid improvements in joint cavity widening and PD signal were observed to week 8 and maintained to week 52. Cartilage damage and bone erosion were stable over 52\ua0weeks. No new safety signals were identified. Conclusion: In Italian CZP-treated patients with moderate-to-severe RA, week 12 clinical responses may be predictive of long-term response at week 52. Rapid improvements in clinical, patient-reported, and musculoskeletal ultrasound outcomes were maintained to week 52. These data may aid rheumatologists to make earlier treatment decisions. Trial Registration: ClinicalTrials.gov identifier, NCT01443364. Funding: UCB Pharma