Abstract 41: Changes In Renal Oxygen Consumption With High-salt Diet Differ Between Sprague Dawley And Dahl Salt Sensitive Rats.

It has appeared evident that blood flow to the renal cortex which is required for glomerular filtration far exceeds the delivery of O 2 required for tubular metabolic needs. Yet, the metabolic needs of kidneys are second only to the heart per gram tissue and changes in O 2 extraction and utilization have not been directly measured in face of enhanced workloads such those imposed by high salt (HS) diets. We have developed techniques enabling continuous 24 hr/d monitoring of renal blood flow (RBF; Transonic flow probe) together with blood pressure (BP, 24hr/d) and intermittent sampling of arterial and renal venous blood over 21 days. O 2 content (mL/dL) was determined as 1.31 х Hemoglobin (Hb) (g/dL) х HbO 2 (%) + 0.003 х PaO 2 (mmHg); O 2 consumption (ml/min) was determined as RBF (ml/min) х (arterial-renal venous O 2 content difference). Sprague Dawley rats (SD; n=7; 10 wk age) were compared to Dahl salt-sensitive (SS; n=6; 8 wk age) rats fed 0.4% NaCl and during the 21 days of 4.0% NaCl (HS) diet. Beginning 7 days following surgery, RBF and BP were recorded 24 hr/day, and arterial and renal venous blood sampled for determination of blood gases (ABL800 FLEX radiometer) at 7, 14 and 21 of the HS diet. Average 24 hr mean BP of SD rats increased with the HS diet from 111±2 to 119±5 mmHg and SS rats rose from 121±5 to 155±9 mmHg (p<0.05); average 24 hr RBF of SD rats rose from 9.2±0.6 to 11.7 + 0.6 ml/min (p<0.05) while SS rats exhibited little change (7.0±0.6 to 7.0 + 0.9). RBF when expressed per gram kidney weight (gkw; determined in separate groups of rats) remained unchanged in both SD and SS rats in response to the HS diet. SS rats exhibited lower levels of RBF gkw than SD rats (p<0.05). Expressed either as absolute values or gkw, O 2 extraction and consumption was increased significantly in SD rats but not SS rats fed the HS diet. The results of the study indicate that despite high levels of RBF per tissue weight, increased metabolic work imposed by a HS diet resulted in a significant increase of RBF, O 2 extraction and consumption in normal rats. In contrast, SS rats exhibited lower levels of RBF but failed to increase either O 2 delivery or extraction. This failure may contribute importantly to altered metabolic substrate utilization in SS rats fed a HS diet, progression of ischemic related injury and hypertension.

An evaluation of machine learning classifiers for next-generation, continuous-ethogram smart trackers

Background Our understanding of movement patterns and behaviours of wildlife has advanced greatly through the use of improved tracking technologies, including application of accelerometry (ACC) across a wide range of taxa. However, most ACC studies either use intermittent sampling that hinders continuity or continuous data logging relying on tracker retrieval for data downloading which is not applicable for long term study. To allow long-term, fine-scale behavioural research, we evaluated a range of machine learning methods for their suitability for continuous on-board classification of ACC data into behaviour categories prior to data transmission. Methods We tested six supervised machine learning methods, including linear discriminant analysis (LDA), decision tree (DT), support vector machine (SVM), artificial neural network (ANN), random forest (RF) and extreme gradient boosting (XGBoost) to classify behaviour using ACC data from three bird species (white stork Ciconia ciconia, griffon vulture Gyps fulvus and common crane Grus grus) and two mammals (dairy cow Bos taurus and roe deer Capreolus capreolus). Results Using a range of quality criteria, SVM, ANN, RF and XGBoost performed well in determining behaviour from ACC data and their good performance appeared little affected when greatly reducing the number of input features for model training. On-board runtime and storage-requirement tests showed that notably ANN, RF and XGBoost would make suitable on-board classifiers. Conclusions Our identification of using feature reduction in combination with ANN, RF and XGBoost as suitable methods for on-board behavioural classification of continuous ACC data has considerable potential to benefit movement ecology and behavioural research, wildlife conservation and livestock husbandry.

Pycnogonids from marine docks located along the west coast of the Gulf of California, Mexico

Sea spiders (Class Pycnogonida Latreille, 1810) are chelicerate arthropods, with an extraordinarily reduced body armed with eight to twelve elongated legs. A literature review of taxonomic and ecological studies of pycnogonids from Mexico identified 49 nominal species (~3.6% out of 1,335 species described worldwide). This low species richness is likely caused by limited taxonomic research and intermittent sampling and research efforts initially carried out by foreign scientists (1893–1996) and later by Mexican scientists. The present study investigates the latitudinal gradient of species richness of the pycnogonids associated with nine marine docks located between Cabo San Lucas (22°53’N) and Santa Rosalía (26°58’N) along the west coast of the Gulf of California, 22°53’N Mexico and provides a detailed morphological re-description of each nominal species using light and scanning electron microscopy. Nine nominal pycnogonid species and one unidentified species in the genus Tanystylum were collected and identified from the biological samples collected between 2011–2017. The highest pycnogonid species richness was recorded at Bahía de La Paz (seven species, 24°14’N) and the lowest species richness at Cabo San Lucas (one species) without an evident latitudinal species richness gradient. Anoplodactylus californicus Hall, 1912 and Ammothella spinifera Cole, 1904 were the most abundant species (52% of the total number of individuals). Tanystylum occidentale (Cole, 1904) and Nymphon apheles Child, 1979 were new geographical records for Mexico and Ammothella symbia Child, 1979 and A. californicus were new records for Baja California Sur state. Adding these new geographical records of pycnogonids increased the species richness previously recorded at Baja California Sur from 20 to 24 nominal species and for Mexico, the species richness increased from 49 to 51 nominal species.

Methane emission detection and flux quantification from exploratory hydraulic fracturing in the United Kingdom, using unmanned aerial vehicle sampling

&lt;p&gt;Unmanned aerial vehicle (UAV) sampling was used to derive high-precision methane mole fraction measurements downwind of the United Kingdom&amp;#8217;s first onshore exploratory operation to horizontally hydraulically fracture shale rock. Sampling took place using two UAVs on five intermittent sampling days between October 2018 and February 2019. One UAV carried an on-board prototype sensor while the other was connected to a sensor on the ground, using a tethered air inlet. Both instruments used near infrared spectroscopy. Methane emissions were observed on one sampling day (14&lt;sup&gt;th&lt;/sup&gt; January 2019) over a 1.4-hour sampling window, due to cold venting of methane following a nitrogen lift. The nitrogen lift procedure was used to induce gas flow during liquid unloading. The near-field Gaussian plume inversion flux quantification method was used to derive four instantaneous flux ranges (within uncertainty) from the four UAV flight surveys conducted during the emission window.&lt;/p&gt;

Survival and breeding interval of an endangered marine vertebrate, the leatherback turtle Dermochelys coriacea, in French Guiana

In the context of global change, endangered species such as sea turtles undergo strong population dynamics changes. Understanding demographic processes inducing such changes is critical for developing appropriate measures for conservation and management. Nesting females of the French Guiana population of leatherback sea turtles Dermochelys coriacea represented 40% of the world’s total in 2001; today, they represent only 10%. Here, we analyze data from the long-term monitoring program of leatherbacks in French Guiana, based on 28 yr of capture-mark-recapture data from 46051 individuals in northwestern French Guiana. We used multievent models (multistate capture-recapture models with state uncertainty) to represent the main peculiarity of the life cycle, intermittent reproduction, and to take advantage of the use of several different types of marks to account for mark loss and incomplete detection. The average annual adult survival probability (mean ± SE) 0.789 ± 0.009 is low compared to published estimates for this species. By combining the estimates of departure and return probabilities, we provide an estimate of the interval among laying seasons equal to 2.777 ± 0.118 yr, which matches previous findings. Taking survival into account, this interval translates into an average of 1.704 ± 0.034 further reproductive seasons for an adult female having just bred, which is remarkably low compared to other long-lived vertebrates. The representation of the life cycle and mark loss in our models provides a sound structure for broader and richer analyses to extract biological information from marked individuals and offers an invaluable source of demographic information on leatherbacks, a species for which only a small segment of the population is accessible to intermittent sampling.

Development of novel Vitamin B12 fortified yogurts using isolated and microencapsulated Vitamin B12

Adults aged > 50 years, which make up to 40% of the European population, are vulnerable to low vitamin B12 (B12) status due to age-related factors that impair digestion and absorption of protein-bound B12 from natural food sources. Older adults are recommended to meeting their dietary B12 intake through the consumption of B12-fortified foods or supplements because these products contain free B12. B12 seems most bioavailable from milk products compared to other food sources, showcasing dairy as a potential vehicle for B12 food fortification. Yogurt is a versatile, popular dairy product, making it a promising food vehicle for B12 fortification to enhance the availability of B12-fortified foods for population groups at risk of B12 deficiency. With the overall goal to develop a novel, B12-fortified dairy product, the objective of this project was to compare the shelf-life stability of different chemical forms of B12 added to yogurt either in isolated or in encapsulated form. For both fortification strategies, we compared methylcobalamin (MeCB), a naturally-occurring B12 form, and cyanocobalamin (CnCB), the synthetic form of B12. Encapsulated microparticles were created by spray-drying a maize starch-derived polymeric material (EUDRAGUARD Natural®) with 1% (w/V) MeCB or CnCB. The release of B12 from encapsulated microparticles was confirmed by in vitro simulated gastrointestinal digestion; maximum B12 release (103% recovery) was achieved under conditions simulating the small intestine, where B12 is absorbed in the human body. Yogurts were produced by incubating whole milk (3.25% milk fat) with yogurt starter bacteria at 43°C overnight; after fermentation and cooling down, isolated (I-MeCB or I-CnCB) or encapsulated B12 powders (E-MeCB or E-CnCB) in the concentration of 50μg of B12/175 g of yogurt were added, creating stirred yogurt. Yogurts were stored at 4°C for eight weeks, with intermittent sampling for B12 stability testing using RIDASCREEN immunoassay. For CnCB-fortified yogurts, I-CnCB and E-CnCB had similar B12 concentrations at baseline (48.3μg and 48.2μg, respectively) and week 8 (53.9μg and 51.4μg, respectively). Difference in B12 content between I-CnCB and E-CnCB was < 5% for both time-points. For MeCB, similar concentrations were found for I-MeCB (64.1μg) and E-MeCB (65.0μg) at baseline; however, at week 8, E-MeCB remained stable (69.8μg) while a pronounced decrease in B12 was observed with I-MeCB (33.3μg). At week 8, I-MeCB B12 concentrations were 52% lower than E-MeCB. In conclusion, CnCB was shown to be the more stable fortificant throughout shelf-life. Encapsulation techniques are a viable option to increase MeCB stability in fortified yogurts.

Comparative Study of Microbiological Monitoring Results from Three Types of Sampling Methods after Gastrointestinal Endoscope Reprocessing

Objective. Compare the effects of three sampling methods on the microbiological monitoring results after reprocessing of gastrointestinal endoscopes, providing scientific basis for improving the monitoring quality of gastrointestinal endoscope cleaning and disinfection. Method. Gastrointestinal endoscopes after reprocessing were selected randomly at the gastrointestinal endoscopy center of a tertiary hospital in Shanghai from October 2018 to February 2019. The endoscopes selected were all sampled in three different methods under continuous sampling and intermittent sampling respectively. Methods used includes, the biopsy channel group (Group A), the entire channel group (Group B), and the disc brush group (Group C). Then the colony forming units (CFU/piece) were counted in the laboratory. Results. A total of 12 endoscopes were sampled by using continuous sampling approach, in which the detection rate of bacteria in disc brush group (33.3%) and entire channel group (33.3%) was higher than biopsy channel group (8.3%). Among the 12 endoscopes sampled with intermittent approach, the detection rate of bacteria from high to low was the disc brush group (50%), the entire channel group (41.7%), and the biopsy channel group (8.3%). Conclusion. Different sampling methods will lead to the difference of microbiological culture results after reprocessing of gastrointestinal endoscope, indicating that the improved sampling method is beneficial to objectively reflect the endoscope cleaning and disinfection effect, and improve the monitoring quality of endoscope disinfection.