Changes In Relative Concentrations Research Articles

Mechanical and tribological properties of layered epoxy coatings synergistically enhanced by graphene and polytetrafluoroethylene: Molecular dynamics simulations and experimental verification

Epoxy resin coatings have high adhesion properties and excellent chemical resistance, and are widely used in the fields of ships, automobiles and electronic appliances. However, the shortcomings of epoxy resin, such as high brittleness, poor thermal stability and insufficient abrasion resistance, seriously affect the durability of the coating. In this paper, the mechanisms of mechanical and tribological properties of graphene (Gr) and polytetrafluoroethylene (PTFE) synergistically reinforced epoxy resin (EP) double layer coatings (with pure epoxy resin as the bottom layer) on Cu substrates were investigated by molecular dynamics simulations. The modeling includes pure epoxy double layer coating (Pure EP-EP), PTFE reinforced epoxy double layer coating (PTFE/EP-EP), and graphene and PTFE synergistically reinforced epoxy double layer coating (Gr/PTFE/EP-EP). The counter frictional part for these coatings is Cu metal. The simulation results show that by analyzing the interaction energy between the coating and the Cu substrate, the double layer coating with Pure EP as the bottom layer is found to have a better adsorption capacity, which can effectively extend the service life of the coating, compared with those with PTFE/EP or Gr/PTFE/EP as bottom layer. By calculating the shear modulus, Young's modulus and bulk modulus of the Gr/PTFE/EP-EP coating, the synergistic enhancement mechanism of the mechanical properties of the Gr/PTFE/EP-EP coating was revealed. In particular, the PTFE/EP-EP coating exhibited a reduction in mechanical properties and the mechanical property simulation results were verified experimentally. Compared with the Pure EP-EP double layer coating, the PTFE/EP-EP and Gr/PTFE/EP-EP double layer coatings showed a reduction in friction coefficient of 9.52 % and 23.81 %, wear rate of 46.69 % and 76.63 %, and mean square displacements (MSD) of 22.4 % and 81.34 %, respectively. The synergistic effect of Gr and PTFE on the tribological performance of Gr/PTFE/EP-EP coatings was better than that of PTFE/EP-EP coatings with PTFE only. The interaction of Gr and PTFE with EP was analyzed by comparing the changes in radius distribution function (RDF), relative concentration, temperature and velocity in the thickness direction of PTFE/EP-EP coatings and Gr/PTFE/EP-EP coatings, which further revealed the synergistic enhancement mechanism by Gr and PTFE.

Increased and sex-differentiated medial prefrontal cortex activation during the MATRICS Consensus Cognitive Battery in schizophrenia: A fNIRS study

Executive impairment in schizophrenia is common, but the mechanism remains unclear. This is the first study to use simultaneously functional near-infrared spectroscopy (fNIRS) to monitor the hemodynamic response in schizophrenia during the MATRICS Consensus Cognitive Battery (MCCB). Here, we monitored relative changes in oxyhemoglobin concentration in the medial prefrontal cortex (mPFC) during Trail Making Test, Symbol Coding Test and Mazes Test of the MCCB in 63 patients (29 females) with schizophrenia and 32 healthy controls (15 females). Results showed that patients with schizophrenia scored lower than healthy controls on all three tests (P < 0.001), but mPFC activation was significantly higher during the test (P < 0.03). Higher activation of the mPFC may reflect abnormal information processing in schizophrenia. In addition, the results also showed sex differences in hemodynamic activation during the task in patients with schizophrenia, and fNIRS has the potential to be a clinical adjunct to screening for cognitive function in schizophrenia.

Effect of membrane properties on the odor emanating from training aids for explosive-detecting canines.

Canines are widely used for real-time detection of explosives and have proven to be on par with instrumental methods. Canines are thought to rely largely upon detection of volatile chemical constituents of the explosives, though not necessarily the explosive itself. Hence, it is crucial to understand the odor available to them as generated by training aids. Previous studies have established that the Training Aid Delivery Device (TADD) developed by SciK9 is a reliable training aid that reduces cross-contamination and doubles as a storage device. A TADD comprises a standardized container, a synthetic membrane, a membrane holder, and a lid. In the work presented, activated charcoal strips were placed above and below the TADD membrane to determine the relative amounts of volatiles emitted by dynamite (i.e., ethylene glycol dinitrate (EGDN) and trinitroglycerin (NG)). The strips were eluted and the extracts tested using gas chromatography-mass spectrometry in negative ion chemical ionization mode. A series of t-tests at 95% confidence level were performed to determine any differences in vapor composition above and below the membranes. Nine synthetic membranes and six glass fiber membranes were tested in this study. It was expected that the relative concentration of volatiles would remain the same on both sides of the membrane; however, selective removal of nitroglycerin by some membranes was observed. Synthetic membranes with larger pore sizes showed no alteration in the vapor composition. Both synthetic and glass fiber membranes did not show a significant change in relative concentration of the other volatile compound in dynamite, i.e., EGDN. Out of all the membranes tested, three synthetic membranes and four glass fiber membranes showed selective alteration in odor availability of nitroglycerin in dynamite. For training purposes, membranes that do not alter the vapor composition should be used in the training aid.

Lattice ultrasensitivity produces large gain in E. coli chemosensing.

E. coli use a regular lattice of receptors and attached kinases to detect and amplify faint chemical signals. Kinase output is characterized by precise adaptation to a wide range of background ligand levels and large gain in response to small relative changes in ligand concentration. These characteristics are well described by models which achieve their gain through equilibrium cooperativity. But these models are challenged by two experimental results. First, neither adaptation nor large gain are present in receptor binding assays. Second, in cells lacking adaptation machinery, fluctuations can sometimes be enormous, with essentially all kinases transitioning together. Here we introduce a far-from equilibrium model in which receptors gate the spread of activity between neighboring kinases. This model achieves large gain through a mechanism we term lattice ultrasensitivity (LU). In our LU model, kinase and receptor states are separate degrees of freedom, and kinase kinetics are dominated by chemical rates far-from-equilibrium rather than by equilibrium allostery. The model recapitulates the successes of past models, but also matches the challenging experimental findings. Importantly, unlike past lattice critical models, our LU model does not require parameters to be fine tuned for function.

Effect of intermittent hypoxia on glucose tolerance in adults with type 2 diabetes

Hypoxia stimulates glucose uptake through an insulin-independent pathway. The purpose of this single-blind randomized study was to determine the acute effect of intermittent hypoxia, consisting of alternating short bouts of breathing hypoxic and normoxic air, on glucose and insulin concentrations during an oral glucose tolerance test in adults with type 2 diabetes. It was hypothesized that intermittent hypoxia would attenuate the increase in glucose and insulin concentrations during an oral glucose tolerance test. Six adults with type 2 diabetes (5 men, age: 51±15 years, HbA1c: 7.3±1.5%) visited the laboratory on two occasions. On both visits, a 2-hour oral glucose tolerance test was performed, with venous blood samples collected 0, 30, 60, 90, and 120 min after ingestion of a high-glucose drink. Following ingestion of the drink, participants were exposed to either an intermittent hypoxia (IH) protocol, consisting of eight 4-min hypoxic cycles at a targeted arterial oxygen saturation of 80% interspersed with breathing room air to resaturation, or an intermittent normoxia (IN) protocol consisting of eight 4-min normoxic cycles interspersed with breathing room air. By design, oxygen saturation was lower during intermittent hypoxia than intermittent normoxia (81±3 vs. 97±1%, p&lt;0.01). Relative changes in plasma glucose concentrations in response to the oral glucose tolerance tests were not different between conditions (IH vs. IN: 30: 42±15 vs. 35±15; 60: 57±26 vs. 65±30; 90: 73±32 vs. 88±30; and 120: 78±26 vs. 83±29 mg/dl, interaction effect: p=0.13). Similarly, the relative changes in insulin concentrations in response to the oral glucose tolerance tests were not different between conditions (IH vs. IN: 30: 14±17 vs. 25±17; 60: 42±36 vs. 48±35; 90: 70±58 vs. 86±60; and 120: 103±72 vs. 125±94 ulU/ml, main effect for condition: p=0.12). While these preliminary results did not reach statistical significance, the observed trends for reduced glucose concentrations in combination with lower insulin concentrations during intermittent hypoxia suggest that short bouts of hypoxia improve glucose tolerance by stimulating glucose uptake independently from the action of insulin. Data from a larger sample size of adults with type 2 diabetes are needed to confirm these preliminary findings. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Molecular-level explanation of interactions of random and block polycarboxylic acid dispersants with bituminous coal in coal–water slurry through experiments and simulations

The adsorption conformations of random-structure polycarboxylic acid (PCR) and block-structure polycarboxylic acid (PCB) on coal surfaces were analyzed from a microscopic perspective. This analysis involved a combination of molecular dynamics (MD) simulations and experiments. The saturation adsorption amount of PCB was found to be significantly much larger than that of PCR. Additionally, observations from the contact angle and X-ray photoelectron spectroscopy confirmed that PCB exhibited superior wetting performance on coal compared to PCR and had a greater adsorption layer thickness. The relative concentration changes and the mean square displacement (MSD) of water indicate that the better adsorption of PCB on the coal surface makes the water molecules more evenly distributed, which improves hydration, increases the thickness of the “adsorption layer”, and enhances the mobility of water molecules. The interaction energy suggests the block structure of PCB is more favorable for molecular extension due to its well-defined structure. This provides a theoretical and experimental basis for expanding the molecular sequence structure design of polycarboxylic acid dispersants.

Prefrontal Cortex Activity During Gait in People With Persistent Symptoms After Concussion

Background Concussions result in transient symptoms stemming from a cortical metabolic energy crisis. Though this metabolic energy crisis typically resolves in a month, symptoms can persist for years. The symptomatic period is associated with gait dysfunction, the cortical underpinnings of which are poorly understood. Quantifying prefrontal cortex (PFC) activity during gait may provide insight into post-concussion gait dysfunction. The purpose of this study was to explore the effects of persisting concussion symptoms on PFC activity during gait. We hypothesized that adults with persisting concussion symptoms would have greater PFC activity during gait than controls. Within the concussed group, we hypothesized that worse symptoms would relate to increased PFC activity during gait, and that increased PFC activity would relate to worse gait characteristics. Methods The Neurobehavior Symptom Inventory (NSI) characterized concussion symptoms. Functional near-infrared spectroscopy quantified PFC activity (relative concentration changes of oxygenated hemoglobin [HbO2]) in 14 people with a concussion and 25 controls. Gait was assessed using six inertial sensors in the concussion group. Results Average NSI total score was 26.4 (13.2). HbO2 was significantly higher (P = .007) for the concussed group (0.058 [0.108]) compared to the control group (−0.016 [0.057]). Within the concussion group, HbO2 correlated with NSI total symptom score (ρ = .62; P = .02), sagittal range of motion (r = .79; P = .001), and stride time variability (r = −.54; P = .046). Conclusion These data suggest PFC activity relates to symptom severity and some gait characteristics in people with persistent concussion symptoms. Identifying the neurophysiological underpinnings to gait deficits post-concussion expands our knowledge of motor behavior deficits in people with persistent concussion symptoms.

Cerebral oxygenation and perfusion kinetics monitoring of military aircrew at high G using novel fNIRS wearable system.

Real-time physiological episode (PE) detection and management in aircrew operating high-performance aircraft (HPA) is crucial for the US Military. This paper addresses the unique challenges posed by high acceleration (G-force) in HPA aircrew and explores the potential of a novel wearable functional near-infrared spectroscopy (fNIRS) system, named NIRSense Aerie, to continuously monitor cerebral oxygenation during high G-force exposure. The NIRSense Aerie system is a flight-optimized, wearable fNIRS device designed to monitor tissue oxygenation 13-20 mm below the skin's surface. The system includes an optical frontend adhered to the forehead, an electronics module behind the earcup of aircrew helmets, and a custom adhesive for secure attachment. The fNIRS optical layout incorporates near-distance, middle-distance, and far-distance infrared emitters, a photodetector, and an accelerometer for motion measurements. Data processing involves the modified Beer-Lambert law for computing relative chromophore concentration changes. A human evaluation of the NIRSense Aerie was conducted on six subjects exposed to G-forces up to +9 Gz in an Aerospace Environmental Protection Laboratory centrifuge. fNIRS data, pulse oximetry, and electrocardiography (HR) were collected to analyze cerebral and superficial tissue oxygenation kinetics during G-loading and recovery. The NIRSense Aerie successfully captured cerebral deoxygenation responses during high G-force exposure, demonstrating its potential for continuous monitoring in challenging operational environments. Pulse oximetry was compromised during G-loading, emphasizing the system's advantage in uninterrupted cerebrovascular monitoring. Significant changes in oxygenation metrics were observed across G-loading levels, with distinct responses in Deoxy-Hb and Oxy-Hb concentrations. HR increased during G-loading, reflecting physiological stress and the anti-G straining maneuver. The NIRSense Aerie shows promise for real-time monitoring of aircrew physiological responses during high G-force exposure. Despite challenges, the system provides valuable insights into cerebral oxygenation kinetics. Future developments aim for miniaturization and optimization for enhanced aircrew comfort and wearability. This technology has potential for improving anti-G straining maneuver learning and retention through real-time cerebral oxygenation feedback during centrifuge training.

CONCENTRATION PROCESSES IN THE RETAIL AND MEAT PROCESSING INDUSTRY IN POLAND AND COMPETITIVE RELATIONSHIPS IN THE FOOD CHAIN

The study investigates the consolidation of Poland’s food retail and meat processing industry from 2010 to 2022. The aim was to assess the relative changes in concentration in these two sectors and to determine whether these processes affected competitive conditions in the food chain. For this purpose, the k-firm concentration ratio (CRk) and HHI index were estimated using Central Statistical Office data supplemented by revenue data for Poland’s largest meat processing and food retail companies. The research reveals a notable trend of mergers and acquisitions among food retail entities. As a result, the share of the top four retailers (CR4) increased from 25% in 2010 to 46% in 2022, and the market moved from a highly competitive to loose oligopoly. At the same time, the concentration of the meat industry increased, but to a lesser extent – CR4 in 2022 reached 33%. This would indicate that food retail firms’ bargaining power towards meat industry firms has increased. However, given the economic potential of firms, there is a slight improvement in the meat industry’s position vis-à-vis food retail. The concentration in the latter has been growing steadily, nevertheless, the sector itself has not been developing as dynamically as the meat processing one.

Establishment of a method to measure the intracellular potassium ion concentration of brain tissue using a simple device.

Intracellular potassium ion (K+) concentration is higher than extracellular K+ concentration. Some cells maintain intracellular potassium levels by taking up extracellular potassium. However, investigating these details requires techniques to measure intracellular potassium concentrations. We established a method to easily measure intracellular potassium concentrations using a simpler electrode. The LAQUAtwin K-11 was capable of linearly quantifying potassium concentrations and was not affected by cellular constituents other than nucleic acids; however, it did not tolerate low temperatures. Interference caused by a high concentration of nucleic acids was eliminated by the addition of cations. It was also suggested that the concentration of nucleic acids in the cell suspension was not sufficiently high to interfere with the measurements. Intracellular potassium concentrations increased and decreased in response to extracellular potassium concentrations. Exposure to valinomycin did not decrease the potassium concentration, suggesting that re-uptake of the potassium released outside the cells occurred immediately. Additionally, potassium concentrations could be measured in the brain tissue homogenates using the device. This measurement method can track the relative changes in potassium concentration in cells under various conditions and in tissues of various disease models.

Evaluation of Salicylic Acid and Methyl Jasmonate as Elicitors in Phyllanthus acuminatus Hairy Roots by Non-Targeted Analysis Using High-Resolution Mass Spectrometry.

Phyllanthus acuminatus has been studied for its vast medical and industrial potential. Phytochemical investigations reveal that the genus is a rich source of lignans, flavonoids, phenolics, terpenoids, and other metabolites. However, the phytochemical profile elucidation of this species still needs further research. The use of eliciting compounds such as salicylic acid and methyl jasmonate has managed to increase the production of secondary metabolites in plant cell cultures. Hairy roots of Phyllanthus acuminatus were produced in 250 mL flasks with a 16 h light/8 h darkness photoperiod under diffused light with a culture time of four weeks. The elicitors salicylic acid and methyl jasmonate were tested in 50 μM and 200 μM concentrations. Non-targeted analysis was done for the different treatments using HR-MS. Identified metabolites were grouped in phenylpropanoids, phenols, and mucic acids, and statistical analysis of relative concentrations was achieved. A significant change in phenols' relative concentrations appeared in the elicitations with salicylic acid. Because of the elicitation treatment, specific compounds increased their concentrations, some of which have known pharmacological effects and are used in treating chronic diseases. The best elicitation treatment was salicylic acid 50 μM as it increased by more than 100% the general content of phenols and phenylpropanoid derivates and triplicates the concentration of mucic acid derivates in treated hairy root extracts. The application of non-targeted analysis showed interesting changes in phytochemical concentration due to elicitation in Phyllanthus acuminatus hairy roots.

Quantifying tissue properties and absolute hemodynamics using coherent spatial imaging.

Measuring hemodynamic function is crucial for health assessment. Optical signals provide relative hemoglobin concentration changes, but absolute measurements require costly, bulky technology. Speckleplethysmography (SPG) uses coherent light to detect speckle fluctuations. Combining SPG with multispectral measurements may provide important physiological information on blood flow and absolute hemoglobin concentration. To develop an affordable optical technology to measure tissue absorption, scattering, hemoglobin concentrations, tissue oxygen saturation (), and blood flow. We integrated reflectance spectroscopy and laser speckle imaging to create coherent spatial imaging (CSI). CSI was validated against spatial frequency domain imaging (SFDI) using phantom-based measurements. In vivo arterial and venous occlusion experiments compared CSI with diffuse optical spectroscopy/diffuse correlation spectroscopy (DOS/DCS) measurements. CSI and SFDI agreed on tissue absorption and scattering in phantom tests. CSI and DOS/DCS showed similar trends and agreement in arterial occlusion results. During venous occlusion, both uncorrected and corrected blood flow decreased with increasing pressure, with an difference in overall blood flow decrease between the methods. CSI and DOS/DCS data showed expected hemoglobin concentrations, , and blood flow trends. CSI provides affordable and comprehensive hemodynamic information. It can potentially detect dysfunction and improve measurements, such as blood pressure, , and metabolism.

Ag-TiO2 for Efficient Methylene Blue Photodegradation Under Visible Light Irradiation

Photocatalysis is one of the environmentally friendly methods for degrading down wastewater contamination. TiO2 as one of the photocatalyst material is claimed can enhance the photocatalytic activity much better, if the band gap energy is reduced. In order to reduce the bandgap energy of TiO2, the novel in this research is that the temperature variations over a 24-hour period at 100 °C, 120 °C, 140 °C, and 160 °C in hydrothermal process to synthesize the photocatalyst material with Ag-doped. Diffraction patterns of Ag-TiO2 show that all sample have tetragonal crystal structure and an anatase phase which also has excellent crystallinity. Some of the nanoparticles on the surface of Ag-TiO2 have a consistent morphology, while other particles are formed irregularly. According to the DRS UV-Vis result, bandgap energy reduced as temperature increased (Eg = 3.2 eV to 2.32 eV). The results from PL Ag-TiO2 160 have the lowest intensity, which indicates a low rate of electron-hole recombination. The Ag-TiO2 160 sample produced the best photocatalytic activity, according to the results of the MB degradation test, with a relative change in concentration of 92.98% for 2 h under visible light. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Serial high-sensitivity troponin-I and long-term risk of myocardial infarction and coronary revascularization in subjects with suspected acute coronary syndrome

Abstract Background Serial high-sensitivity troponin-I (hsTnI) concentrations are associated with mortality in individuals with suspected acute coronary syndrome. However, their relation to myocardial infarction and revascularization events is unknown. Purpose To determine short- and long-term risks of myocardial infarction and revascularization (PCI or CABG) according to hsTnI concentrations and their changes from baseline, in patients with suspected acute coronary syndrome. Methods Through Danish national registries, we identified subjects who underwent two hsTnI measurements (Siemens TnI Flex® Reagent, 99th percentile upper reference limit, 45 ng/l) separated by 1-7 hours, during hospitalization for myocardial infarction, unstable angina, observation for suspected myocardial infarction, or chest pain from 2012 through 2019. Individuals were stratified according to their hsTnI concentration pattern (main groups: normal, rising, persistently elevated, or falling) and the magnitude of hsTnI concentration change (secondary groups: &amp;lt;20%, &amp;gt;20 to 50%, or &amp;gt;50% in either direction). We calculated standardized absolute and relative risks of myocardial infarction and coronary revascularization using multivariable logistic regression with average treatment effect modeling, a method that ensures equal distribution of factors that may affect the risk of outcomes across the various groups of interest. Results A total of 20,609 individuals were included of whom 22.4% were discharged with a diagnosis of myocardial infarction, 4.8% with unstable angina, and 72.8% with observation for suspected myocardial infarction or chest pain. Median age was 63.2 years, and 53.1% were male. Considering known cardiovascular disease, 21.3% had coronary artery disease, 7.0% had undergone prior PCI or CABG, 8.1% had heart failure, and 10.7% had atrial fibrillation or flutter. The standardized risk of being diagnosed with myocardial infarction was lowest in subjects with two normal hsTnI values and highest in those with persistently elevated concentrations. Within each main group, the likelihood of being diagnosed with myocardial infarction generally appeared to increase with more pronounced hsTnI changes. The standardized risk of undergoing coronary revascularization mimicked this pattern, although among persons with two elevated hsTnI levels, the long-term-risk was not influenced by relative concentration changes. The findings are summarized in the Figure. Conclusions Among individuals with suspected acute coronary syndrome, those with a persistently elevated hsTnI concentration consistently had the highest risk of being diagnosed with myocardial infarction and undergoing coronary revascularization. The risk of these outcomes was, for the most part, also positively associated with the magnitude of hsTnI change.Figure

An Optical Micro/Nano Fiber Sensor for Monitoring Respiration

In the field of clinical medicine, the real-time monitoring of carbon dioxide (CO2) gas exhaled by the human body is of great significance. At present, the detection devices on the market mainly work by sucking a small amount of gas from the nasal cavity into the detection device, and they present some problems such as overly long sampling tubes, easy blockage or distortion, and an abnormal gas dispersion. In this paper, a micro/nano optical fiber sensor that can directly detect respiration is proposed and is characterized by the relative change in CO2 concentration. The measurement is achieved by using the principle of high evanescent field absorption, and the operating band is 2.004 μm. The sensing effects of micro/nano fibers with different diameters are compared, and the experiment proves that a micro/nano fiber with a diameter of 1 μm can be measured. The light intensity change over 30 s was measured, and the breathing rate was 10–11 times/min. The sensor can achieve a rapid real-time response to CO2 gas detection and is small in size, low-cost, and easy to replace. It has a great application potential in clinical scenarios such as in gastrointestinal endoscopes that require real-time monitoring of human respiration.

Elucidation of the effects of autochthonous starter on nitrogen-containing compounds during fermentation of Yujiangsuan by metabolomics.

To understand the role of microorganisms in nitrogen (N)-containing compound changes during the processing of Yujiangsuan by autochthonous starter cultures, the GC-TOF-MS-based metabolomics method was adopted to investigate the effects of Weissella cibaria and Lactobacillus plantarum. The results demonstrated that inoculation of autochthonous strains led to differential metabolites, such as fatty acids, organic oxygen compounds, and carboxylic acids on day 4 to day 12 of fermentation. The N-containing compounds under the inoculated fermentation group showed a faster relative concentration change. Nucleotide metabolism and arginine and proline metabolism exerted an influence on the formation of N-containing compounds. Apart from that, the effect of W. cibaria and L. plantarum on the hydrolysis of macromolecules was the main factor causing differences in major N-containing compounds.

Multi-Method Quantification of Acetyl-Coenzyme A and Further Acyl-Coenzyme A Species in Normal and Ischemic Rat Liver.

Thioesters of coenzyme A (CoA) carrying different acyl chains (acyl-CoAs) are central intermediates of many metabolic pathways and donor molecules for protein lysine acylation. Acyl-CoA species largely differ in terms of cellular concentrations and physico-chemical properties, rendering their analysis challenging. Here, we compare several approaches to quantify cellular acyl-CoA concentrations in normal and ischemic rat liver, using HPLC and LC-MS/MS for multi-acyl-CoA analysis, as well as NMR, fluorimetric and spectrophotometric techniques for the quantification of acetyl-CoAs. In particular, we describe a simple LC-MS/MS protocol that is suitable for the relative quantification of short and medium-chain acyl-CoA species. We show that ischemia induces specific changes in the short-chain acyl-CoA relative concentrations, while mild ischemia (1-2 min), although reducing succinyl-CoA, has little effects on acetyl-CoA, and even increases some acyl-CoA species upstream of the tricarboxylic acid cycle. In contrast, advanced ischemia (5-6 min) also reduces acetyl-CoA levels. Our approach provides the keys to accessing the acyl-CoA metabolome for a more in-depth analysis of metabolism, protein acylation and epigenetics.

Review of recent advances in frequency-domain near-infrared spectroscopy technologies [Invited

Over the past several decades, near-infrared spectroscopy (NIRS) has become a popular research and clinical tool for non-invasively measuring the oxygenation of biological tissues, with particular emphasis on applications to the human brain. In most cases, NIRS studies are performed using continuous-wave NIRS (CW-NIRS), which can only provide information on relative changes in chromophore concentrations, such as oxygenated and deoxygenated hemoglobin, as well as estimates of tissue oxygen saturation. Another type of NIRS known as frequency-domain NIRS (FD-NIRS) has significant advantages: it can directly measure optical pathlength and thus quantify the scattering and absorption coefficients of sampled tissues and provide direct measurements of absolute chromophore concentrations. This review describes the current status of FD-NIRS technologies, their performance, their advantages, and their limitations as compared to other NIRS methods. Significant landmarks of technological progress include the development of both benchtop and portable/wearable FD-NIRS technologies, sensitive front-end photonic components, and high-frequency phase measurements. Clinical applications of FD-NIRS technologies are discussed to provide context on current applications and needed areas of improvement. The review concludes by providing a roadmap toward the next generation of fully wearable, low-cost FD-NIRS systems.

Improving Surface Wear Resistance of Polyimide by Inserting KH550 Grafted GO.

To improve the wear resistance of polyimide (PI), surface modification was developed. In this study, the tribological properties of graphene (GN), graphene oxide (GO), and KH550-grafted graphene oxide (K5-GO) modified PI were evaluated by molecular dynamics (MD) at the atomic level. The findings indicated that the addition of nanomaterials can significantly enhance the friction performance of PI. The friction coefficient of PI composites decreased from 0.253 to 0.232, 0.136, and 0.079 after coating GN, GO and K5-GO, respectively. Among them, the K5-GO/PI exhibited the best surface wear resistance. Importantly, the mechanism behind the modification of PI was thoroughly revealed by observing the wear state, analyzing the changes of interfacial interactions, interfacial temperature, and relative concentration.

Decoding the physiological response of plants to stress using deep learning for forecasting crop loss due to abiotic, biotic, and climatic variables

This paper presents a simple method for detecting both biotic and abiotic stress in plants. Stress levels are measured based on the increase in nutrient uptake by plants as a mechanism of self-defense when under stress. A continuous electrical resistance measurement was used to estimate the rate of change of nutrients in agarose as the growth medium for Cicer arietinum (Chickpea) seeds. To determine the concentration of charge carriers in the growth medium, Drude’s model was used. For identifying anomalies and forecasting plant stress, two experiments were conducted and outliers were found in electrical resistance and relative changes in carrier concentration. Anomaly in the first iteration was detected by applying k-Nearest Neighbour, One Class Support Vector Machine and Local Outlier Factor in unsupervised mode on electrical resistance data. In the second iteration, the neural network-based Long Short Term Memory method was used on the relative change in the carrier concentration data. As a result of the change in resistance of growth media during stress, nutrient concentrations shifted by 35%, as previously reported. Farmers who cater to small communities around them and are most affected by local and global stress factors can use this method of forecasting.