2,965 research outputs found
Erratum: 3D bioprinted in vitro secondary hyperoxaluria model by mimicking intestinal-oxalatemalabsorption-related kidney stone disease (Applied Physics Reviews (2022) 9 (041408) DOI: 10.1063/5.0087345)
No full text© 2023 Author(s).This article was originally published online on 21 November 2022 with an incorrect affiliation identifier for author Dong-Woo Cho. It is correct as it appears above. All online versions of this article were corrected on 23 November 2022. AIP Publishing apologizes for this error.11Nsciescopu
Multiple-sprint sport exercise and carbohydrate-protein ingestion in humans
No full textThe aim of the present thesis was to examine the potential for acute carbohydrate-protein (CHO-P) ingestion to enhance performance and recovery from exercise designed to simulate the demands of multiple-sprint sports (MSSs). Chapter 3 of the thesis explored the inter- and intra-day reliability and concurrent validity of non-motorised treadmill ergometry (NMT) for the assessment of short-distance sprint performance [i.e. 10-30 m). There were no significant mean differences between NMT variables recorded on the same day or between days. Ratio limits of agreement indicated that the best agreement was in 20 [1.02 */-=- 1.09) and 30 m [1.02 */* 1.07) sprint times, peak [1.00 */T 1.06) and mean (0.99 */+ 1.07) running speed and step length (0.99 */-=- 1.09) and frequency (1.01 */+ 1.06). The poorest agreement was observed for time to peak running speed (1.10 */* 1.47). Significant differences were observed between NMT and over-ground sprint times across all distances, with times being lower (faster) by approximately 25-30% over-ground. The correlations between NMT and over-ground variables were generally modest (r5 = 0.44 - 0.67), and optimal for time to cover 30 m on Day 2 (rs = 0.8). Chapter 4 sought to examine the efficacy of CHO-P ingestion during 4 h of recovery from the Loughborough Intermittent Shuttle Test (LIST) when compared to CHO matched for energy (ISOEN) or CHO (ISOCHO) in a typical CHO beverage. There were significant increases over time in muscle soreness, and reductions in extensor and flexor peak torque (by approximately 9%, 9% and 8%, and 13 %, 13% and 11% at 60 deg-s-1) and jump performance (10%, 7% and 5%) with the ingestion of CHO-P, ISOEN and ISOCHO, respectively. Beverage type x time interactions were not significant for any of these variables, indicating that changes in each variable were similar for all groups. Decrements in sprint performance assessed on the NMT were typically small and not different between beverage types (<4%), although sprint times over 20 and 30 m remained elevated for 48 h post-exercise. Accordingly, Chapter 4 provided no clear evidence for a benefit of ingesting CHO-P in the hours after exercise to enhance recovery of muscle function and selected performance variables following MSS activity. Chapters 5 and 6 of the thesis aimed to examine the effect of CHO-P ingestion during simulated MSS exercise. In Chapter 5, it was observed that sprint times, HR and gut fullness increased over the course of the LIST, with no influence of consuming each of the different beverages. In contrast, there was a main effect of time (P < 0.001), and drink (P = 0.042) observed for RPE, which was lower (P < 0.001) during the LIST in the CHO-P condition (16.9 ± 1.4) than in either the ISOCHO (17.8 ± 1.1) or ISOEN (17.7 ± 1.3). However, time to exhaustion was not different (P = 0.29) between CHO-P (468.3 ± 268.5 s), ISOCHO (443.4 ± 286.3 s) and ISOEN (446.2 ± 282.08 s), although these times did equate to a non-significant mean improvement of 4% in the CHO-P trial. Chapter 6 demonstrated that during a modified version of the LIST with two self-regulated blocks of exercise intensity, participants had a higher average speed (8.1 ± 0.3 cf. 7.9 ± 0.5 knvlr1) during the final (self-regulated) 15 min block of the LIST in the CHO-P condition compared to CHO. Whilst the mechanisms for such an improvement are not certain, the attenuated rise in RPE observed in Chapter 5, and increased blood urea concentration observed in Chapter 6, with CHO-P ingestion may suggest altered central fatigue and/or increased protein oxidation enhances performance during MSSs
The antihypertensive effects of the Jamaican Cho-Cho (Sechium edule)
No full textThe experiments reported in this study constitute a preliminary investigation into the possible hypotensive effect of the Jamaican Cho-Cho (Sechium edule). Experiments were conducted in a random and blind fashion on two sub species of Sechium edule. Both the pulp and the peel were examined for hypotensive activity. Water-soluble extracts were prepared from these components of the fruit and injected into anaesthetised rats. Various cardiovascular parameters were measured including heart rate, mean arterial pressure (MAP) and several ECG intervals. We report that all extracts tested produced a fall in blood pressure with little change in ECG intervals. Extract B produced the least change in heart rate with a fall in MAP of approximately 23 mmHg. Changes in heart rate with all extracts appeared to be minimal as an ED25 value could only be determined for extract A, and ED10 values could not be evaluated for extracts C and D. The mechanism(s) by which these extracts produce their hypotensive effects could not be determined in these preliminary experiments. However, it appears not to involve direct effects on cardiac tissue. This conclusion is based on the finding that it took a minimum of 10 to 15 seconds for the hypotensive action to manifest post bolus. Future experiments will be aimed at delineating the mechanism(s) involved in decreasing MAP.Peer reviewedfinal article publishe
Forgetting Fragments from Evolving Ontologies
No full textOntologies underpin the semantic web; they define the concepts and their relationships contained in a data source. An increasing number of ontologies are available on-line, but an ontology that combines information from many different sources can grow extremely large. As an ontology grows larger, more resources are required to use it, and its response time becomes slower. Thus, we present and evaluate an on-line approach that forgets fragments from an OWL ontology that are infrequently or no longer used, or are cheap to relearn, in terms of time and resources. In order to evaluate our approach, we situate it in a controlled simulation environment, RoboCup OWLRescue, which is an extension of the widely used RoboCup Rescue platform, which enables agents to build ontologies automatically based on the tasks they are required to perform. We benchmark our approach against other comparable techniques and show that agents using our approach spend less time forgetting concepts from their ontology, allowing them to spend more time deliberating their actions, to achieve a higher average score in the simulation environment
Intensity-dependent resonant transmission of x-rays in solid-density aluminum plasma
No full textX-ray free-electron lasers (XFELs) provide unique opportunities to generate and investigate dense plasmas. The absorption and transmission properties of x-ray photons in dense plasmas are important in characterizing the state of the plasmas. Experimental evidence shows that the transmission of x-ray photons through dense plasmas depends greatly on the incident XFEL intensity. Here, we present a detailed analysis of intensity-dependent x-ray transmission in solid-density aluminum using collisional-radiative population kinetics calculations. Reverse saturable absorption (RSA), i.e., an increase in x-ray absorption with intensity has been observed for photon energies below the K-absorption edge and in the intensity range of 1016-1017 W/cm2 for XFEL photons with 1487 eV. At higher intensities, a transition from RSA to saturable absorption (SA) is predicted; thus, the x-ray absorption decreases with intensity above a threshold value. For XFEL photon energies of 1501 eV and 1515 eV, the transition from RSA to SA occurs at XFEL intensities between 1017-1018 W/cm2. Electron temperatures are predicted to be in the range of 30-50 eV for the given experimental conditions. Detailed population kinetics of the charge states explains the intensity-dependent absorption of x-ray photons and the fast modulation of XFEL pulses for both RSA and SA. © 2018 Author(s
Magnetic Resonance Diffusion-Weighted Imaging for Detecting Fundal Intracholecystic Papillary Neoplasm inside Rokitansky-Aschoff Sinuses: A Comparison of Two Cases and a Literature Review
No full textRokitansky-Aschoff sinuses (RAS) are a common imaging finding in gallbladder adenomyomatosis (ADM), often presenting as fundal cystic spaces. Intracholecystic papillary neoplasm (ICPN) is a relatively uncommon pre-invasive tumor of the gallbladder epithelium that rarely involves RAS mucosa. We compare two cases that showed similar fundal cystic spaces resembling RAS, in which Magnetic Resonance Diffusion-Weighted Imaging (MR-DWI) was valuable for detecting (or ruling out) an underlying malignant ICPN. Evidence from the literature overall supports the role of MR-DWI for detecting intracholecystic malignant tissue
sj-docx-3-sel-10.1177_17585732221102393 - Supplemental material for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients
No full textSupplemental material, sj-docx-3-sel-10.1177_17585732221102393 for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients by Christopher A White, Calista L Dominy, Justin E Tang, Nicholas L Pitaro, Akshar V Patel, Kevin C Wang, Jun S Kim, Samuel K Cho and Paul J Cagle in Shoulder & Elbow</p
sj-docx-2-sel-10.1177_17585732221102393 - Supplemental material for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients
No full textSupplemental material, sj-docx-2-sel-10.1177_17585732221102393 for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients by Christopher A White, Calista L Dominy, Justin E Tang, Nicholas L Pitaro, Akshar V Patel, Kevin C Wang, Jun S Kim, Samuel K Cho and Paul J Cagle in Shoulder & Elbow</p
sj-docx-1-sel-10.1177_17585732221102393 - Supplemental material for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients
No full textSupplemental material, sj-docx-1-sel-10.1177_17585732221102393 for Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients by Christopher A White, Calista L Dominy, Justin E Tang, Nicholas L Pitaro, Akshar V Patel, Kevin C Wang, Jun S Kim, Samuel K Cho and Paul J Cagle in Shoulder & Elbow</p
A kinetic description of the Warburg effect in CHO cells
No full textThe Warburg effect has been known about for nearly 100 years. It is characterised by a high rate of glycolytic flux and production of lactate in highly proliferating cells, relative to their slower growing counterparts. This phenomenon is still observed in environments where there is sufficient oxygen to catabolise glucose into CO2 via oxidative phosphorylation. High growth is a trait common among both cancer cells and cells engineered to produce biopharmaceuticals. The Warburg effect has often been described as an enigma due to it being less energy and carbon effecient than oxidative phosphorylation. This leads to the overall question of this thesis: How do glycolytic enzymes regulate the Warburg effect?.The organism we are investigating the Warburg effect in are known as Chinese Hasmster Ovary (CHO) cells. CHO cells are a common cell line used in the production of biopharmaceuticals. The laboratory we are working in has developed a non–Warburgcell line, CHO-ZeLa, that has a similar growth rate to its parent cell line, CHO-S, which is Warburg positive. In this thesis we investigate this high growth, non-Warburg phenotype and compare it to its parent stain using a kinetic model.We developed a Bayesian kinetic modelling framework called Maud that uses Hamiltonian Monte Carlo for posterior sampling. To evaluate our framework we carried out a case study of a representitive metabolic model, which compared full posterior sampling to an approximation of the posterior using point estimation. We showed that the posterior distribution is not well approximated by point estimation methods. Additionally, full Bayesian sampling translated to tighter confidence intervals and improved predictions. We made Maud available as a Python package that automates ODE construction, diagnostics, and posterior predictions.We collected a dataset consisiting of 6 cell lines that included their proteome, metabolomeand fluxome (measured using 13C metabolic flux analysis). This dataset was crucial indeveloping a kinetic model of glycolysis in CHO cells that spaned the Embden-Meyerhof-Parnas (EMP) and pentose phosphate (PP) pathways.Our comparative model of the CHO-S and CHO-ZeLa cell lines showed that hexokinase 2 is a strong regulator of glycolysis and may be mediated via mitochondrial binding,a mechanism not previously modelled. Furthermore, our results aligned with previous models of the Warburg effect in CHO cells that suggest that allosteric regulation of phosphofructokinase M is required for the Warburg effect. Kinetic modelling has the side effect of helping identify when mechanisms may be incorrectly understood. We were able to identify that the current understanding of triosphosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase mechanisms are likely missing additional regulation, which was indicated by the surrounding metabolomics data not fitting the model.The results also suggest that we require a method to account for phosphorylation in metabolic models. We therefore developed a Monod-Wynman-Changeaux (MWC) analogous model of phosphorylation, and a combinatorial model of phosphorylation. These models will futher be used to model the hexokinase 2 and 6-phosphofructo-2-kinase/fructose2,6-bisphosphatase mechansism, which were identified as essential to regulate the Warburg effect.</div
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