22 research outputs found
Effect of lactation stage and concurrent pregnancy on milk composition in the bottlenose dolphin
Although many toothed whales (Cetacea: Odontoceti) lactate for 2–3 years or more, it is not known whether milk composition is affected by lactation stage in any odontocete species. We collected 64 pooled milk samples spanning 1–30 months postpartum from three captive bottlenose dolphins Tursiops truncatus. Milks were assayed for water, fat, crude protein (TN × 6.38) and sugar; gross energy was calculated. Ovulation and pregnancy were determined via monitoring of milk progesterone. Based on analysis of changes in milk composition for each individual dolphin, there were significant increases (P<0.05) in fat (in all three dolphins) and crude protein (in two of three), and a decrease (P<0.05) in water (in two of three) over the course of lactation, but the sugar content did not change. In all three animals, the energy content was positively correlated with month of lactation, but the percentage of energy provided by crude protein declined slightly but significantly (P<0.05). At mid-lactation (7–12 months postpartum, n=17), milk averaged 73.0±1.0% water, 12.8±1.0% fat, 8.9±0.5% crude protein, 1.0±0.1% sugar, 1.76±0.09 kcal g−1 (=7.25 kJ g−1) and 30.3±1.3% protein:energy per cent. This protein:energy per cent was surprisingly high compared with other cetaceans and in relation to the growth rates of calves. Milk progesterone indicated that dolphins ovulated and conceived between 413 and 673 days postpartum, following an increase in milk energy density. The significance of these observed compositional changes to calf nutrition will depend on the amounts of milk produced at different stages of lactation, and how milk composition and yield are influenced by sampling procedure, maternal diet and maternal condition, none of which are known
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Investigation of a Thermally Regenerative Reactor System
A novel cyclic reactor system is proposed for heterogeneous,
catalytic, gas-phase reactions. This system utilises the inherent
characteristics of the thermal regenerator to impose favourable
reaction temperature profiles along the catalyst bed without setting
up radial temperature gradients. This control of the longitudinal
profile enables higher conversions to be obtained than those from
steady state reactors. The reactor system is investigated by computer
simulation using the endothermic, reversible dehydrogenation of ethylbenzene
to styrene in the presence of steam as an example. The higher
conversions obtained from the proposed system produce utility cost
savings in this process.
Kinetics presented in the literature for this reaction are compared
and assessed. None of these is entirely satisfactory and a more representative
set is derived. Models for the reacting and regenerating
bed are discussed and suitable models are presented. A comparative
study of solution methods for these models is carried out in order to
determine one which gives an accurate solution and also minimises
computing requirements.
The most suitable operating policy lor the system, with an endothermic
reaction, is the use of constant heat inputs with constant flow
during each period of operation, This allows the bed inlet temperature
to vary with time, but it seems likely that the damping effect of the
system will be large and the inlet temperatures may be assumed constant
Counter-current, rather than co-current, operation of the system is
preferred,
A simple design procedure, which does not require the solution of
the cyclic model, is described. This is found to give good predictions
of the cyclic steady state performance of the system.
Che effect of the various system parameters on the performance
is investigated. The major parameters for a given bed size are the
period time, reactor and regenerator steam flows and regenerator
inlet temperature. It is shown that the system can give higher
conversions than a steady state reactor but i.t may be desirable to
operate at lower conversions to reduce the operating cost. Guidelines
for optimising the system are discussed
Immunohistochemical Characterisation of GLUT1, MMP3 and NRF2 in Osteosarcoma
Osteosarcoma (OSA) is an aggressive bone malignancy. Unlike many other malignancies, OSA outcomes have not improved in recent decades. One challenge to the development of better diagnostic and therapeutic methods for OSA has been the lack of well characterized experimental model systems. Spontaneous OSA in dogs provides a good model for the disease seen in people and also remains an important veterinary clinical challenge. We recently used RNA sequencing and qRT-PCR to provide a detailed molecular characterization of OSA relative to non-malignant bone in dogs. We identified differential mRNA expression of the solute carrier family 2 member 1 (SLC2A1/GLUT1), matrix metallopeptidase 3 (MMP3) and nuclear factor erythroid 2–related factor 2 (NFE2L2/NRF2) genes in canine OSA tissue in comparison to paired non-tumor tissue. Our present work characterizes protein expression of GLUT1, MMP3 and NRF2 using immunohistochemistry. As these proteins affect key processes such as Wnt activation, heme biosynthesis, glucose transport, understanding their expression and the enriched pathways and gene ontologies enables us to further understand the potential molecular pathways and mechanisms involved in OSA. This study further supports spontaneous OSA in dogs as a model system to inform the development of new methods to diagnose and treat OSA in both dogs and people