Experimental thermodynamics of the helix-random coil transition. II. Calorimetric measurement of transition enthalpies of poly A in acid aqueous solution

Klump H, Ackermann T, Neumann E. Experimental thermodynamics of the helix-random coil transition. II. Calorimetric measurement of transition enthalpies of poly A in acid aqueous solution. Biopolymers. 1969;7(3):423-431.The enthalpy change accompanying the double helix-coil transition of polyriboadenylic acid (poly A) in aqueous solution has been measured optically and calorimetrically in the pH range 5.7-4.5. The course of this cooperative transition was followed optically by measuring changes in ultraviolet absorption as a function of temperature at different pH values, and calorimetrically by determining the heat capacity of the solution through the transition region. From the latter measurements, the enthalpy of transition was calculated. It is shown, that H is dependent on pH as it is expected from the influence of protonation of the double helix of poly A

DNA-mediated biomineralization of a new planar Pt-complex

The crystal growth morphology of a coordination complex of Pt(II) that crystallizes from solution can be controlled by using a second molecular species such as peptides or other organic compounds. Examples of crystal growth controlled by nucleic acids are few. In this article we describe the use of branched three-way junction (3WJ) DNA to influence the crystal growth of a planar platinum compound, cis-[(2, 2′-bipyridyl)N,N-di(2-hydroxyethyl)-N′-benzoylthioureatoplatinum(II)]chloride. Platinum complexes with extended planar aromatic residues are capable of stacking in the absence as well as in the presence of linear DNA double helices. This feature is based on the interaction of the compound with DNA through intercalation, resulting in the prevention of binding of DNA polymerase. Microscopic one-dimensional crystals were observed under these conditions. In the presence of the branched 3WJ DNA, however, additional nucleation sites are present, resulting in extended crystal growth of unique Pt compounds. At least two different crystal modifications were observed using transmission electron microscopy

Speaking of That: Terms to Avoid or Reconsider in the Eating Disorders Field

Inspired by an article on 50 terms that, in the interest of clarity in scientific reasoning and communication in psychology, psychiatry, and allied fields, “should be avoided or at most be used sparingly and only with explicit caveats,”1 we propose a list of terms to avoid or think twice about before using when writing for the International Journal of Eating Disorders (IJED). Drawing upon our experience as reviewers or editors for the IJED, we generated an abridged list of such terms. For each term, we explain why it made our list and what alternatives we recommend. We hope that our list will contribute to improved clarity in scientific thinking about eating disorders, and that it will stimulate discussion of terms that may need to be reconsidered in our field's vocabulary to ensure the use of language that is respectful and sensitive to individuals who experience an eating disorder

Causes and consequences of tool shape variation in New Caledonian crows

This study was funded through a BBSRC David Phillips Fellowship (BB/G023913/2; C.R.), studentships from JASSO (S.S.; L12126010025) and BBSRC/University of St Andrews (B.C.K.), and a JSPS overseas research fellowship (S.S.; H28/1018).Hominins have been making tools for over three million years [1], yet the earliest known hooked tools appeared as recently as 90,000 years ago [2]. Hook innovation is likely to have boosted our ancestors’ hunting and fishing efficiency [3], marking a major transition in human technological evolution. The New Caledonian crow is the only non-human animal known to craft hooks in the wild [4 ; 5]. Crows manufacture hooked stick tools in a multi-stage process, involving the detachment of a branch from suitable vegetation; “sculpting” of a terminal hook from the nodal joint; and often additional adjustments, such as length trimming, shaft bending, and bark stripping [4; 6 ; 7]. Although tools made by a given population share key design features [4; 6 ; 8], they vary appreciably in overall shape and hook dimensions. Using wild-caught, temporarily captive crows, we experimentally investigated causes and consequences of variation in hook-tool morphology. We found that bird age, manufacture method, and raw-material properties influenced tool morphology, and that hook geometry in turn affected crows’ foraging efficiency. Specifically, hook depth varied with both detachment technique and plant rigidity, and deeper hooks enabled faster prey extraction in the provided tasks. Older crows manufactured tools of distinctive shape, with pronounced shaft curvature and hooks of intermediate depth. Future work should explore the interactive effects of extrinsic and intrinsic factors on tool production and deployment. Our study provides a quantitative assessment of the drivers and functional significance of tool shape variation in a non-human animal, affording valuable comparative insights into early hominin tool crafting [9].PostprintPeer reviewe

Preliminary observations of tool-processing behaviour in Hawaiian crows Corvus hawaiiensis

This project was funded through a BBSRC David Phillips Fellowship (BB/G023913/2 to C.R.), and a PhD studentship by the BBSRC and the University of St Andrews (to B.K.). Funding for the ‘Alalā conservation breeding programme was provided by the U.S. Fish and Wildlife Service, State of Hawai‘i Division of Forestry and Wildlife, Moore Family Foundation, several anonymous donors, and San Diego Zoo Global.Very few animal species habitually make and use foraging tools. We recently discovered that the Hawaiian crow is a highly skilled, natural tool user. Most captive adults in our experiment spontaneously used sticks to access out-of-reach food from a range of extraction tasks, exhibiting a surprising degree of dexterity. Moreover, many birds modified tools before or during deployment, and some even manufactured tools from raw materials. In this invited addendum article, we describe and discuss these observations in more detail. Our preliminary data, and comparisons with the better-studied New Caledonian crow, suggest that the Hawaiian crow has extensive tool-modification and manufacture abilities. To chart the full extent of the species’ natural tool-making repertoire, we have started conducting dedicated experiments where subjects are given access to suitable raw materials for tool manufacture, but not ready-to-use tools.Publisher PDFPeer reviewe

DNA barcoding identifies cryptic animal tool materials

Funding: Biotechnology and Biological Sciences Research Council (BBSRC) (Grants BB/G023913/1 and BB/G023913/2 to C.R., and studentship to B.C.K.), the School of Biology at the University of St Andrews (studentships to M.P.S. and B.C.K.), and the Leverhulme Trust (Grant RPG-2015-273 to P.M.H.).Some animals fashion tools or constructions out of plant materials to aid foraging, reproduction, self-maintenance, or protection. Their choice of raw materials can affect the structure and properties of the resulting artifacts, with considerable fitness consequences. Documenting animals’ material preferences is challenging, however, as manufacture behavior is often difficult to observe directly, and materials may be processed so heavily that they lack identifying features. Here, we use DNA barcoding to identify, from just a few recovered tool specimens, the plant species New Caledonian crows (Corvus moneduloides) use for crafting elaborate hooked stick tools in one of our long-term study populations. The method succeeded where extensive fieldwork using an array of conventional approaches—including targeted observations, camera traps, radio-tracking, bird-mounted video cameras, and behavioral experiments with wild and temporarily captive subjects—had failed. We believe that DNA barcoding will prove useful for investigating many other tool and construction behaviors, helping to unlock significant research potential across a wide range of study systems.Publisher PDFPeer reviewe

Source levels of social sounds in migrating humpback whales (Megaptera novaeangliae)

The source level of an animal sound is important in communication, since it affects the distance over which the sound is audible. Several measurements of source levels of whale sounds have been reported, but the accuracy of many is limited because the distance to the source and the acoustic transmission loss were estimated rather than measured. This paper presents measurements of source levels of social sounds (surface-generated and vocal sounds) of humpback whales from a sample of 998 sounds recorded from 49 migrating humpback whale groups. Sources were localized using a wide baseline five hydrophone array and transmission loss was measured for the site. Social vocalization source levels were found to range from 123 to 183 dB re 1 mu Pa @ 1 m with a median of 158 dB re 1 mu Pa @ 1 m. Source levels of surface-generated social sounds ("breaches" and "slaps") were narrower in range (133 to 171 dB re 1 mu Pa @ 1 m) but slightly higher in level (median of 162 dB re 1 mu Pa @ 1 m) compared to vocalizations. The data suggest that group composition has an effect on group vocalization source levels in that singletons and mother-calf-singing escort groups tend to vocalize at higher levels compared to other group compositions. VC 2013 Acoustical Society of America

Oxaliplatin, fluorouracil and leucovorin for advanced biliary system adenocarcinomas: a prospective phase II trial

We studied the activity of combined oxaliplatin and fluorouracil-leucovorin in 16 consecutive patients with advanced biliary tract adenocarcinomas. The disease control rate (responses and stable disease) was 56% (95% confidence interval, 29–84%) and the median overall survival time was 9.5 months (range 0.9–26.8+). Therefore, this regimen might be active in biliary adenocarcinomas with further evaluation necessary