Dissolution of Antarctic diatoms at low temperatures

The bSiO2 ooze of the Southern Ocean (S.O) has long provided a source of discussion over how and why such thick accumulations exist underlying a region of relatively low diatom productivity. The low temperatures and high nutrient conditions of many regions of the S.O are understood to be optimal for Fragilariopsis kerguelensis, a slow growing diatom with a high silicate (Si), yet low iron requirement, thus making it a dominant species in the surface ocean of this region. The high level of silification and robust characteristics of F.kerguelensis has been hypothesised as being a main factor contributing to its persistence in the sediments of the S.O. However, specific dissolution characteristics of this species have not previously been elucidated, nor have the effects that temperature and aggregation might have in determining the diatom composition of deep ocean sediments. Laboratory experiments tested the hypothesis that the rate of bSiO2 dissolution of aggregated F.kerguelensis is lower than that of the less silicified Chaetoceros debilis. The effects of temperature and physiological stage of the cells on the dissolution rate of freshly aggregated cells was also investigated. Four experiments were undertaken; one with F.kerguelensis at 5º C, one with senescent C.debilis at 5º C, one with senescent C.debilis at 15º C, and one with exponentially growing C.debilis at 5º C. Aggregates were formed in rolling tanks and Si dissolution monitored for 4 months. bSiO2 dissolution was significantly lower for F.kerguelensis as compared to C.debilis at 5º C. Dissolution of C.debilis aggregates formed using exponentially growing cells started with a lag period of 1 week in comparison to those formed using senescent cells, and dissolution increased markedly with temperature

A temperature-controlled single-crystal growth cell for the in situ measurement and analysis of face-specific growth rates

The design and construction of a growth cell for the precision measurement of face-specific single-crystal growth rates are presented. Accurate mechanical drawings in SolidWorks of the cell and individual components are provided, together with relevant construction models. A general methodology for its use in the measurement of single-crystal growth rates and their underpinning growth mechanism is presented and illustrated with representative data provided for the crystal growth of the {011} and {001} faces of RS-ibuprofen single crystals grown in ethano­lic solutions. Analysis of these data highlights the utility of the methodology in morphological model development and crystallization process design

Diversity of Zoanthids (Anthozoa: Hexacorallia) on Hawaiian Seamounts: Description of the Hawaiian Gold Coral and Additional Zoanthids

The Hawaiian gold coral has a history of exploitation from the deep slopes and seamounts of the Hawaiian Islands as one of the precious corals commercialised in the jewellery industry. Due to its peculiar characteristic of building a scleroproteic skeleton, this zoanthid has been referred as Gerardia sp. (a junior synonym of Savalia Nardo, 1844) but never formally described or examined by taxonomists despite its commercial interest. While collection of Hawaiian gold coral is now regulated, globally seamounts habitats are increasingly threatened by a variety of anthropogenic impacts. However, impact assessment studies and conservation measures cannot be taken without consistent knowledge of the biodiversity of such environments. Recently, multiple samples of octocoral-associated zoanthids were collected from the deep slopes of the islands and seamounts of the Hawaiian Archipelago. The molecular and morphological examination of these zoanthids revealed the presence of at least five different species including the gold coral. Among these only the gold coral appeared to create its own skeleton, two other species are simply using the octocoral as substrate, and the situation is not clear for the final two species. Phylogenetically, all these species appear related to zoanthids of the genus Savalia as well as to the octocoral-associated zoanthid Corallizoanthus tsukaharai, suggesting a common ancestor to all octocoral-associated zoanthids. The diversity of zoanthids described or observed during this study is comparable to levels of diversity found in shallow water tropical coral reefs. Such unexpected species diversity is symptomatic of the lack of biological exploration and taxonomic studies of the diversity of seamount hexacorals

Absence of Evidence for MHC–Dependent Mate Selection within HapMap Populations

The major histocompatibility complex (MHC) of immunity genes has been reported to influence mate choice in vertebrates, and a recent study presented genetic evidence for this effect in humans. Specifically, greater dissimilarity at the MHC locus was reported for European-American mates (parents in HapMap Phase 2 trios) than for non-mates. Here we show that the results depend on a few extreme data points, are not robust to conservative changes in the analysis procedure, and cannot be reproduced in an equivalent but independent set of European-American mates. Although some evidence suggests an avoidance of extreme MHC similarity between mates, rather than a preference for dissimilarity, limited sample sizes preclude a rigorous investigation. In summary, fine-scale molecular-genetic data do not conclusively support the hypothesis that mate selection in humans is influenced by the MHC locus

On the scent of sexual attraction

A study in the current issue of BMC Biology has identified a mouse major urinary protein as a pheromone that attracts female mice to male urine marks and induces a learned attraction to the volatile urinary odor of the producer. See research article http://www.biomedcentral.com/1741-7007/8/7

Assessment of a novel, capsid-modified adenovirus with an improved vascular gene transfer profile

<p>Background: Cardiovascular disorders, including coronary artery bypass graft failure and in-stent restenosis remain significant opportunities for the advancement of novel therapeutics that target neointimal hyperplasia, a characteristic of both pathologies. Gene therapy may provide a successful approach to improve the clinical outcome of these conditions, but would benefit from the development of more efficient vectors for vascular gene delivery. The aim of this study was to assess whether a novel genetically engineered Adenovirus could be utilised to produce enhanced levels of vascular gene expression.</p> <p>Methods: Vascular transduction capacity was assessed in primary human saphenous vein smooth muscle and endothelial cells using vectors expressing the LacZ reporter gene. The therapeutic capacity of the vectors was compared by measuring smooth muscle cell metabolic activity and migration following infection with vectors that over-express the candidate therapeutic gene tissue inhibitor of matrix metalloproteinase-3 (TIMP-3).</p> <p>Results: Compared to Adenovirus serotype 5 (Ad5), the novel vector Ad5T*F35++ demonstrated improved binding and transduction of human vascular cells. Ad5T*F35++ mediated expression of TIMP-3 reduced smooth muscle cell metabolic activity and migration in vitro. We also demonstrated that in human serum samples pre-existing neutralising antibodies to Ad5T*F35++ were less prevalent than Ad5 neutralising antibodies.</p> <p>Conclusions: We have developed a novel vector with improved vascular transduction and improved resistance to human serum neutralisation. This may provide a novel vector platform for human vascular gene transfer.</p&gt

Reconciling unevenly sampled paleoclimate proxies: a Gaussian kernel correlation multiproxy reconstruction

Reconstructing past hydroclimatic variability using climate-sensitive paleoclimate proxies provides context to our relatively short instrumental climate records and a baseline from which to assess the impacts of human-induced climate change. However, many approaches to reconstructing climate are limited in their ability to address sampling variability inherent in different climate proxies. We iteratively optimise an ensemble of possible reconstruction data series to maximise the Gaussian kernel correlation of Rehfeld et al. (2011) which reconciles differences in the temporal resolution of both the target variable and proxies or covariates. The reconstruction method is evaluated using synthetic data with different degrees of sampling variability and noise. Two examples using paleoclimate proxy records and a third using instrumental rainfall data with missing values are used to demonstrate the utility of the method. While the Gaussian kernel correlation method is relatively computationally expensive, it is shown to be robust under a range of data characteristics and will therefore be valuable in analyses seeking to employ multiple input proxies or covariates

Use of the intraosseous screw for unilateral upper molar distalization and found well balanced occlusion

BACKGROUND: The aim of this study was to present a temporary anchorage device with intraosseous screw for unilateral molar distalization to make a space for the impacted premolar and to found well balanced occlusion in a case. CASE PRESENTATION: A 13-year-old male who have an impacted premolar is presented with skeletal Class I and dental Class 2 relationship. The screw was placed and immediately loaded to distalize the left upper first and second molar. The average distalization time to achieve an overcorrected Class I molar relationship was 3.6 months. There was no change in overjet, overbite, or mandibular plane angle measurements. Mild protrusion (0.5 mm) of the upper left central incisor was also recorded. CONCLUSION: Immediately loaded intraosseous screw-supported anchorage unit was successful in achieving sufficient unilateral molar distalization without anchorage loss. This treatment procedure was an alternative treatment to the extraction therapy