Transparency on scientific instruments

Scientists and commercial scientific instrument makers have a shared incentive against discloseing an instrument maker's contributions to research. Stricter rules to encourage reporting of such collaboration would help to improve transparency and reproducibility

Effect of holding office on the behavior of politicians

Does being elected to political office change an individual’s behavior? Some scholars and policymakers assert that elected officials are inherently different from nonpoliticians, whereas others argue that political institutions or the culture of politics inculcate certain behaviors. We identify the effect of holding office on behavior. We recruit in-office and out-of-office politicians in Zambia to participate in behavioral games that measure reciprocity, a behavioral trait that underpins various interactions in the political arena from bribery to lobbying to legislative bargaining. We find that holding elected office causes an increase in reciprocity. The policy implication of this finding is that political institutions, culture, and incentive structures can be designed to shape the behavior and choices of society’s leaders

Bony ingrowth potential of 3D-printed porous titanium alloy: a direct comparison of interbody cage materials in an in vivo ovine lumbar fusion model.

Background contextThere is significant variability in the materials commonly used for interbody cages in spine surgery. It is theorized that three-dimensional (3D)-printed interbody cages using porous titanium material can provide more consistent bone ingrowth and biological fixation.PurposeThe purpose of this study was to provide an evidence-based approach to decision-making regarding interbody materials for spinal fusion.Study designA comparative animal study was performed.MethodsA skeletally mature ovine lumbar fusion model was used for this study. Interbody fusions were performed at L2-L3 and L4-L5 in 27 mature sheep using three different interbody cages (ie, polyetheretherketone [PEEK], plasma sprayed porous titanium-coated PEEK [PSP], and 3D-printed porous titanium alloy cage [PTA]). Non-destructive kinematic testing was performed in the three primary directions of motion. The specimens were then analyzed using micro-computed tomography (µ-CT); quantitative measures of the bony fusion were performed. Histomorphometric analyses were also performed in the sagittal plane through the interbody device. Outcome parameters were compared between cage designs and time points.ResultsFlexion-extension range of motion (ROM) was statistically reduced for the PTA group compared with the PEEK cages at 16 weeks (p-value=.02). Only the PTA cages demonstrated a statistically significant decrease in ROM and increase in stiffness across all three loading directions between the 8-week and 16-week sacrifice time points (p-value≤.01). Micro-CT data demonstrated significantly greater total bone volume within the graft window for the PTA cages at both 8 weeks and 16 weeks compared with the PEEK cages (p-value<.01).ConclusionsA direct comparison of interbody implants demonstrates significant and measurable differences in biomechanical, µ-CT, and histologic performance in an ovine model. The 3D-printed porous titanium interbody cage resulted in statistically significant reductions in ROM, increases in the bone ingrowth profile, as well as average construct stiffness compared with PEEK and PSP

Revised genomic structure of the human ghrelin gene and identification of novel exons, alternative splice variants and natural antisense transcripts

Background Ghrelin is a multifunctional peptide hormone expressed in a range of normal tissues and pathologies. It has been reported that the human ghrelin gene consists of five exons which span 5 kb of genomic DNA on chromosome 3 and includes a 20 bp non-coding first exon (20 bp exon 0). The availability of bioinformatic tools enabling comparative analysis and the finalisation of the human genome prompted us to re-examine the genomic structure of the ghrelin locus. Results We have demonstrated the presence of an additional novel exon (exon -1) and 5' extensions to exon 0 and 1 using comparative in silico analysis and have demonstrated their existence experimentally using RT-PCR and 5' RACE. A revised exon-intron structure demonstrates that the human ghrelin gene spans 7.2 kb and consists of six rather than five exons. Several ghrelin gene-derived splice forms were detected in a range of human tissues and cell lines. We have demonstrated ghrelin gene-derived mRNA transcripts that do not code for ghrelin, but instead may encode the C-terminal region of full-length preproghrelin (C-ghrelin, which contains the coding region for obestatin) and a transcript encoding obestatin-only. Splice variants that differed in their 5' untranslated regions were also found, suggesting a role of these regions in the post-transcriptional regulation of preproghrelin translation. Finally, several natural antisense transcripts, termed ghrelinOS (ghrelin opposite strand) transcripts, were demonstrated via orientation-specific RT-PCR, 5' RACE and in silico analysis of ESTs and cloned amplicons. Conclusion The sense and antisense alternative transcripts demonstrated in this study may function as non-coding regulatory RNA, or code for novel protein isoforms. This is the first demonstration of putative obestatin and C-ghrelin specific transcripts and these findings suggest that these ghrelin gene-derived peptides may also be produced independently of preproghrelin. This study reveals several novel aspects of the ghrelin gene and suggests that the ghrelin locus is far more complex than previously recognised

Upper-slope jets and gulf stream filaments inshore of the Charleston Bump during winter 2012

A 3-month-long field program conducted in winter 2012 inshore of the seaward deflection of the Gulf Stream at the Charleston Bump observed several 7-21-day periods of strong (> 0.5ms-1) equatorward alongshelf flow over the upper continental slope. In sea surface temperature images, these phenomena resemble and appear linked to warm filaments, features known to be associated with meanders of the Gulf Stream as it traverses the southeast coast of North America. However, the character of these upper-slope features differs from previous descriptions of filaments, hence we describe them as ''upper-slope jets.'' We document the characteristics of the jets, which are approximately 30 km in width, centered on the 200-m isobath, with a maximum temperature variation at depth, and reasonably long-lived. Southwestward flow within the jet extends to 200m and is in approximate thermal wind balance below a surface mixed layer. Maximum transport is estimated to be about 2.0 Sv (1 Sv ≡ 106m3 s-1), driving a net equatorward along-shelf velocity over the deployment period. For this time period, at least, the jets form the equatorward flow of the shoreward flank of the Charleston Gyre. We suggest the features resemble the Pinocchio's Nose Intrusion recently described by Zhang and Gawarkiewicz. Large-amplitude meander crests with sufficiently strong curvature vorticity are a plausible source of initiation of the upper-slope jets

Complex organisation and structure of the ghrelin antisense strand gene GHRLOS, a candidate non-coding RNA gene

<p>Abstract</p> <p>Background</p> <p>The peptide hormone ghrelin has many important physiological and pathophysiological roles, including the stimulation of growth hormone (GH) release, appetite regulation, gut motility and proliferation of cancer cells. We previously identified a gene on the opposite strand of the ghrelin gene, ghrelinOS (<it>GHRLOS</it>), which spans the promoter and untranslated regions of the ghrelin gene (<it>GHRL</it>). Here we further characterise <it>GHRLOS</it>.</p> <p>Results</p> <p>We have described <it>GHRLOS </it>mRNA isoforms that extend over 1.4 kb of the promoter region and 106 nucleotides of exon 4 of the ghrelin gene, <it>GHRL</it>. These <it>GHRLOS </it>transcripts initiate 4.8 kb downstream of the terminal exon 4 of <it>GHRL </it>and are present in the 3' untranslated exon of the adjacent gene <it>TATDN2 </it>(TatD DNase domain containing 2). Interestingly, we have also identified a putative non-coding <it>TATDN2-GHRLOS </it>chimaeric transcript, indicating that <it>GHRLOS </it>RNA biogenesis is extremely complex. Moreover, we have discovered that the 3' region of <it>GHRLOS </it>is also antisense, in a tail-to-tail fashion to a novel terminal exon of the neighbouring <it>SEC13 </it>gene, which is important in protein transport. Sequence analyses revealed that <it>GHRLOS </it>is riddled with stop codons, and that there is little nucleotide and amino-acid sequence conservation of the <it>GHRLOS </it>gene between vertebrates. The gene spans 44 kb on 3p25.3, is extensively spliced and harbours multiple variable exons. We have also investigated the expression of <it>GHRLOS </it>and found evidence of differential tissue expression. It is highly expressed in tissues which are emerging as major sites of non-coding RNA expression (the thymus, brain, and testis), as well as in the ovary and uterus. In contrast, very low levels were found in the stomach where sense, <it>GHRL </it>derived RNAs are highly expressed.</p> <p>Conclusion</p> <p><it>GHRLOS </it>RNA transcripts display several distinctive features of non-coding (ncRNA) genes, including 5' capping, polyadenylation, extensive splicing and short open reading frames. The gene is also non-conserved, with differential and tissue-restricted expression. The overlapping genomic arrangement of <it>GHRLOS </it>with the ghrelin gene indicates that it is likely to have interesting regulatory and functional roles in the ghrelin axis.</p

The proximal first exon architecture of the murine ghrelin gene is highly similar to its human orthologue

BACKGROUND: The murine ghrelin gene (Ghrl), originally sequenced from stomach tissue, contains five exons and a single transcription start site in a short, 19 bp first exon (exon 0). We recently isolated several novel first exons of the human ghrelin gene and found evidence of a complex transcriptional repertoire. In this report, we examined the 5' exons of the murine ghrelin orthologue in a range of tissues using 5' RACE. -----FINDINGS: 5' RACE revealed two transcription start sites (TSSs) in exon 0 and four TSSs in intron 0, which correspond to 5' extensions of exon 1. Using quantitative, real-time RT-PCR (qRT-PCR), we demonstrated that extended exon 1 containing Ghrl transcripts are largely confined to the spleen, adrenal gland, stomach, and skin. -----CONCLUSION: We demonstrate that multiple transcription start sites are present in exon 0 and an extended exon 1 of the murine ghrelin gene, similar to the proximal first exon organisation of its human orthologue. The identification of several transcription start sites in intron 0 of mouse ghrelin (resulting in an extension of exon 1) raises the possibility that developmental-, cell- and tissue-specific Ghrl mRNA species are created by employing alternative promoters and further studies of the murine ghrelin gene are warranted

Old traces, read anew - 'The Reading Hermit' painting in the light of X-ray fluorescence

There exist several very similar looking versions of the painting ‘The Reading Hermit’, all allegedly painted by Rembrandt Harmenszoon van Rijn (approx. in ∼1630 A.D., Leiden). The classification of Rembrandt's paintings, which were produced by Rembrandt himself, in his academy by his students and the ones being mere copies is a crucial and difficult task. We gathered background evidence and performed elemental analyses by non-destructive micro-X-ray fluorescence (micro-XRF) in order to elucidate the painting's provenance. Elemental distributions of Ca, Mn, Fe and Cu show that the painting was presumably changed during the painting process, which indicates, together with neutron autoradiography (NAR) investigations, that this version of ‘The Reading Hermit’ is not a copy

The transcriptome of the bowhead whale Balaena mysticetus reveals adaptations of the longest-lived mammal

Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest-lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold-adapted baleen whale species. Here, we report the first genome-wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean-specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid-rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt's bat. The bowhead whale transcriptome is a valuable resource for the study of this remarkable animal, including the evolution of longevity and its important correlates such as resistance to cancer and other diseases

High-frequency acoustic scattering from turbulent oceanic microstructure : the importance of density fluctuations

Author Posting. © Acoustical Society of America, 2003. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 114 (2003): 2685-2697, doi:10.1121/1.1614258.Acoustic scattering techniques provide a unique and powerful tool to remotely investigate the physical properties of the ocean interior over large spatial and temporal scales. With high-frequency acoustic scattering it is possible to probe physical processes that occur at the microstructure scale, spanning submillimeter to centimeter scale processes. An acoustic scattering model for turbulent oceanic microstructure is presented in which the current theory, which only accounts for fluctuations in the sound speed, has been extended to include fluctuations in the density as well. The inclusion of density fluctuations results in an expression for the scattering cross section per unit volume, σv, that is explicitly dependent on the scattering angle. By relating the variability in the density and sound speed to random fluctuations in oceanic temperature and salinity, σv has been expressed in terms of the temperature and salinity wave number spectra, and the temperature-salinity co-spectrum. A Batchelor spectrum for temperature and salinity, which depends on parameters such as the dissipation rates of turbulent kinetic energy and temperature variance, has been used to evaluate σv. Two models for the temperature-salinity co-spectrum have also been used. The predictions indicate that fluctuations in the density could be as important in determining backscattering as fluctuations in the sound speed. Using data obtained in the ocean with a high resolution vertical microstructure profiler, it is predicted that scattering from oceanic microstructure can be as strong as scattering from zooplankton.This work was supported in part by ONR, NSF, and the Woods Hole Oceanographic Institution