Tandem Mass Tag Labeling-Based Analysis to Characterize Muscle-Specific Proteome Changes during Postmortem Aging of Bison Longissimus Lumborum and Psoas Major Muscles

The objective of the study was to examine the variations in sarcoplasmic proteomes of bison longissimus lumborum (LL) and psoas major (PM) muscles during postmortem aging utilizing tandem mass tag (TMT) isobaric labeling coupled with liquid chromatography mass-spectrometry (LC-MS/MS) for the categorization of muscles with muscle-specific inherent color stability. A total of 576 proteins were identified (P < 0.05) in both bison LL and PM muscles, where 97 proteins were identified as differentially abundant (fold change > 1.5, P < 0.05) from the three comparisons between muscles during postmortem aging periods (PM vs LL at 2 d, 7 d and 14 d). Among those proteins, the most important protein groups based on functions are related to electron transport chain (ETC) or oxidative phosphorylation, tricarboxylic acid cycle (TCA), ATP transport, carbohydrate metabolism, fatty acid oxidation, chaperones, oxygen transport, muscle contraction, calcium signaling, and protein synthesis. In PM, most of the proteins from ETC, TCA cycle, fatty acid oxidation, ATP and oxygen transport, and muscle contraction were more abundant or exhibited increased expression during aging compared to LL. On the other hand, the proteins involved in carbohydrate metabolism, chaperone function and protein synthesis mostly exhibited decreased expression in PM muscle relative to LL. These results clearly demonstrate that the proteins associated with oxidative metabolism showed increased expression in PM muscles. This indicates that oxidative damage or subsequent color deterioration resulted in bison PM muscles being attacked by the reactive oxygen species produced during those metabolic process. In contrast, proteins involved in glycolysis and chaperone activity exhibited a decrease in expression in bison PM muscles, resulting decline in color stability compared with LL. Because glycolytic enzymes and chaperones maintain oxidative and/or color stability by producing reducing equivalents in glycolytic pathway and with the protein folding ability of chaperones, respectively in LL muscles.

Function of oxygen transport in the blood of patients in a state of alcohol deprivation in blood in vitro incubation with ethanol solution

Objective. To estimate the in vitro effect of ethanol on the function of oxygen transport in the blood of patients in a state of alcohol deprivation and in healthy donors.Materials and methods. We analyzed blood samples from 13 male patients aged 22–56 in a state of alcohol deprivation and 11 males aged 20-45 in whom this diagnosis was excluded. The blood was incubated with ethanol solution at a final concentration of 50 μmol/L. The parameters of the function of oxygen transport (р50, рО2, рСО2, рН, АВЕ, НСО3-, ТСО2,SВЕ, SBC) of the blood taken from the cubital vein using an ABL-330 “Radiometr” microgas analyzer were determined.Results. The patients in a state of alcohol deprivation reveal increased affinity of hemoglobin for oxygen, and their acid-base status of the blood becomes alkaline. When ethanol is added in vitro to the blood of patients, the affinity of hemoglobin for oxygen decreases.Conclusion. Decreased affinity of hemoglobin for oxygen upon the in vitro addition of ethanol in the examined patients indicates compensatory and adaptive changes in the oxygen transport of the blood in response to chronic ethanol consumption.

Anaesthesia-Specifi c Oxygen Transport Assessment in Robot-Assisted Pelvic Surgery: a Clinical Trial

Background. Robot-assisted pelvic surgery rapidly becomes a choice in surgeries for gynaecological oncology and urology. These interventions require special settings (pneumoperitonaeum and Trendelenburg position), which inevitably and systemically impact oxygen transport. Low oxygen delivery during surgery associates with manifold adverse outcomes. A single universal oxygen delivery threshold is impractical, as oxygen consumption must be taken into account. This study examines the effects of pneumoperitonaeum and Trendelenburg position on oxygen transport in patients of ASA functional class I–III (as per American Society of Anaesthesiologists).Materials and methods. Delivery, consumption, oxygen extraction, perioperative adverse events and type of general anaesthesia were prospectively studied in 126 adult patients.Results and discussion. Mean oxygen consumption was 242 mL/min/m2 , mean oxygen delivery — 612 mL/min/m2 . Oxygen delivery was below median 529 mL/min/m2 in 54 (43 %) patients. Perioperative adverse events developed in 36 (29 %) patients. A strong correlation (r > 0.500; p<0.001) between oxygen delivery and consumption was observed in 54 patients. Blood lactate level of 2.7 mmol/L at surgery end was indicative of inadequate oxygen delivery.Conclusion. No relationship was revealed between oxygen delivery and adverse perioperative events, and neither — between oxygen delivery and consumption relative to a particular anaesthetic.

Modeling the Effect of Low Pt loading Cathode Catalyst Layer in Polymer Electrolyte Fuel Cells: Part I. Model Formulation and Validation

A model for the cathode catalyst layer (CL) is presented, which is validated with previous experimental data in terms of both performance and oxygen transport resistance. The model includes a 1D macroscopic description of proton, electron and oxygen transport across the thickness, which is locally coupled to a 1D microscopic model that describes oxygen transport toward Pt sites. Oxygen transport from the channel to the CL and ionic transport across the membrane are incorporated through integral boundary conditions. The model is complemented with data of effective transport and electrochemical properties extracted from multiple experimental works. The results show that the contribution of the thin ionomer film and Pt/ionomer interface increases with the inverse of the roughness factor. Whereas the contribution of the water film and the water/ionomer interface increases with the ratio between the geometric area and the surface area of active ionomer. Moreover, it is found that CLs diluted with bare carbon provide lower performance than non-diluted samples due to their lower electrochemical surface area and larger local oxygen transport resistance. Optimized design of non-diluted samples, with a good distribution of the overall oxygen flux among Pt sites, is critical to reduce mass transport losses at low Pt loading.

Modeling of Hierarchical Cathodes for Li-Air Batteries with Improved Discharge Capacity

The non-aqueous Li-air battery is considered to be a promising energy source for electric-vehicles owing to its ultrahigh theoretical power density. However, its commercialization is limited by the attained lower energy density value, which is mainly due to pore blockage and passivation which requires a more strategic design of the cathode. In this work, we have developed and validated a detailed one-dimensional continuum model of Li-Air battery that helps in examining the potential of hierarchical cathodes in guiding and enhancing the efficiency of ions transport and discharge product formation inside microstructures. The obtained results reveal the importance of reducing the tortuosity (shorten the path of oxygen transport) and increasing porosity at the airside of the hierarchical cathode, which improved discharge capacity at approximately 20.9 and 56%, respectively. The improved capacity is due to enhanced effective oxygen transport, impregnation of electrolyte, alignment of pores, and formation of permeable and low crystalline aggregates of Li2O2. Hence, strategies considering these insights can help in the design and fabrication of non-aqueous Li-air batteries with enhanced power density and capacity.

A Kernel for Calculating PEM Fuel Cell Distribution of Relaxation Times

Impedance of all oxygen transport processes in PEM fuel cell has negative real part in some frequency domain. A kernel for calculation of distribution of relaxation times (DRT) of a PEM fuel cell is suggested. The kernel is designed for capturing impedance with negative real part and it stems from the equation for impedance of oxygen transport through the gas-diffusion transport layer (doi:10.1149/2.0911509jes). Using recent analytical solution for the cell impedance, it is shown that DRT calculated with the novel K2 kernel correctly captures the GDL transport peak, whereas the classic DRT based on the RC-circuit (Debye) kernel misses this peak. Using K2 kernel, analysis of DRT spectra of a real PEMFC is performed. The leftmost on the frequency scale DRT peak represents oxygen transport in the channel, and the rightmost peak is due to proton transport in the cathode catalyst layer. The second, third, and fourth peaks exhibit oxygen transport in the GDL, faradaic reactions on the cathode side, and oxygen transport in the catalyst layer, respectively.