Oxygen System Research Articles

Ефективність декскетопрофену трометамолу при лікуванні післяопераційного болю

Актуальність. Питання лікування післяопераційного болю залишаються предметом активного обговорення і великої кількості медичних публікацій. Мета дослідження: оцінити ефективність застосування декскетопрофену трометамолу при лікуванні післяопераційного больового синдрому у хворих, які перенесли оперативне втручання на органах черевної порожнини. Матеріали і методи. Обстежено 40 хворих, яких було прооперовано з приводу патології органів черевної порожнини. Залежно від характеру післяопераційного знеболювання (застосування диклофенаку натрію або декскетопрофену трометамолу) хворі були розподілені на 2 групи. Результати. При лікуванні післяопераційного больового синдрому диклофенаком натрію упродовж перших двох діб після операції зберігався помірний больовий синдром, що потребувало додаткового знеболювання наркотичними анальгетиками у 80–90 % хворих (дворазово — в 1-шу добу, одноразово — в 2-гу добу). Післяопераційний біль супроводжувався симпатикотонією, гіперглікемією, вазоспазмом і тахікардією. Формувався відносно гіпердинамічний тип кровообігу. Активація симпатичної ланки вегетативної нервової системи сприяла збільшенню системного транспорту і споживання кисню. Застосування декскетопрофену трометамолу при лікуванні післяопераційного больового синдрому було ефективним і дозволяло якісно обмежити розвиток післяопераційної гіпералгезії. Висновки. Традиційне використання диклофенаку натрію для лікування болю після планового оперативного втручання в абдомінальній хірургії зберігає помірний больовий синдром, що у 80–90 % хворих вимагає неодноразового додаткового введення наркотичних анальгетиків протягом перших двох діб. При застосуванні декскетопрофену трометамолу больовий синдром зменшується до легкого вже з 1-ї доби після операції, що у 40–60 % пацієнтів вимагає тільки одноразового додаткового знеболювання, сприяє нормалізації судинного тонусу і серцевого ритму, транспорту і споживання кисню при відносній парасимпатикотонії.

A novel two-step strategy to fabricate phase-pure SnS photoelectrodes with tunable conductivity: formation mechanism and photoelectrochemical properties

Tin monosulfide (SnS) is a narrow band gap semiconductor for visible-light harvesting, however the easy formation of secondary phases such as Sn2S3 and SnS2 severely restricts its photoelectrochemical (PEC) properties. Herein, we propose a novel two-step strategy to fabricate phase-pure SnS photoelectrodes with tunable conductivity on Ti foil substrate and carefully investigated the formation mechanism and PEC properties. The tunable conductivity is determined by Na2SO4 pretreatment before annealing, which is supported by energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and electron paramagnetic resonance characterizations. Na+ adsorbed to the edge of the precursor SnS2 nanosheets forming a dangling bond adsorption will protect S2− against reaction with the trace oxygen in the chemical vapor deposition system within a certain temperature range (<525 °C), thereby reducing the generation of S vacancies to adjust the S/Sn ratio and further regulate the conductivity type. Moreover, the anodic photocurrent density of SnS thin films was about 0.32 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE) with the separation and injection efficiency of 1.22% and 72.78% and a maximum cathodic photocurrent density reaching approximately −0.36 mA cm−2 at 0 V vs RHE with the separation and injection efficiency 1.15% and 5.44% respectively. The method shown in this work provides an effective approach to control the electrical conductivity of SnS thin films with considerable photocurrent response for phase-pure SnS.

Ferroelectric-enhanced BiVO4-BiFeO3 photoelectrocatalysis for efficient, stable and large-current-density oxygen evolution

The efficient BiVO4 photoanodes converting light to charge carriers and further oxidizing water to oxygen in PEC system is the gordian technical barrier for water spliltting, because that BiVO4 remain suffering from sluggish water oxidation kinetic, severe surface recombination and inefficient carrier separation. Firstly, the suitable cocatalysts loading can solve the sluggish kinetics of surface reaction and serious recombination of photogenerated charge carriers. Secondly, constructing heterostructures composed of multi-semiconductors can improve the separation efficiency of charge carriers and light absorption range. On the other hand, the existence of the built-in electric field can also provide a driving force for the transport of photoinduced charge carriers, thus enhancing separation efficiency. Herein, a ferroelectric enhanced photoelectrocatalysis system, by taking BiVO4 and Co3O4 as photocatalyst and cocatalyst, and coupling the ferroelectric material BiFeO3 to form BiVO4-BiFeO3 heterojunction was developed. The Co3O4 cocatalyst provided active sites for OER and BiVO4-BiFeO3 heterojunction promoted carrier separation. Besides of the regulation of heterojunction structure, BiFeO3 could also form the local internal electric field through ferroelectric polarization at a low voltage, which further promoted carrier separation and increased photocurrent. The as-prepared Co3O4/BiVO4-BiFeO3 sample exhibited remarkable electrocatalytic and photoelectrochemical activity for OER in 1 M KOH, an impressive photocurrent density at 1.23 V vs. RHE was achieved under AM 1.5 G light (2.24 mA/cm2), which was approximately double higher than those of Co3O4/BiVO4 and Co3O4/BiFeO3, respectively. Importantly, after the ferroelectric polarization of BiFeO3 was performed, photocurrent densities of 4.51 mA/cm2 at 1.23 V and 1280 mA/cm2 at 1.86 V vs. RHE were obtained under AM 1.5 G light, attesting the polarization-induced electric field contributed to enhance photoelectrochemical catalytic performance. The large-current-density OER obtained was also an important preponderance for the practicability.

Reduced Effective Oxygen Delivery and Ventilation with a Surgical Facemask Placed under Compared to over an Oxygen Mask: A Comparative Study.

Objectives Consensus guidelines for perioperative anesthesia management during the COVID-19 pandemic recommend that patients wear a facemask in addition to their oxygen mask or nasal cannulae following tracheal extubation, where this is practical. The effects on effective oxygen delivery and ventilation of a surgical facemask under compared to over an oxygen (O2) mask are unclear. Design Single-center, comparative pilot study. Setting. Endoscopy procedure room at a major academic hospital. Subjects Five healthy anesthesiologists. Interventions. Using a carbon dioxide (CO2) sampling line positioned at the lips, the fraction of inspired O2 (FiO2), fraction of expiratory O2 (FeO2), expiratory end-tidal CO2 (EtCO2), and respiratory rate (RR) were measured under the following conditions: (1) a surgical facemask only, (2) a surgical facemask under an O2 mask, (3) an O2 mask only, and (4) a surgical facemask over an O2 mask. Measurements and Main Results. The sampled fractional expired oxygen (FeO2) at the lips was significantly lower when the surgical facemask was under compared to when over the O2 mask (27.9± 1.68 vs. 49.9 ± 6.27, p = 0.001), while there was no significant difference in inspired oxygen (FiO2). The sampled expiratory EtCO2 was significantly higher when the surgical facemask was under the O2 mask compared to when over the O2 mask (28.3 ± 8.5 vs. 23.5 ± 7.6, p = 0.026). The RR was not significantly different when the surgical facemask was under compared to over the O2 mask. Conclusions Effective oxygen delivery and ventilation was reduced (lower FeO2 and increased EtCO2) when a surgical facemask was placed under compared to over an O2 mask.

Seizures Caused by Exposure to Hyperbaric Oxygen in Rats Can Be Predicted by Early Changes in Electrodermal Activity.

Hyperbaric oxygen (HBO2) is breathed during undersea operations and in hyperbaric medicine. However, breathing HBO2 by divers and patients increases the risk of central nervous system oxygen toxicity (CNS-OT), which ultimately manifests as sympathetic stimulation producing tachycardia and hypertension, hyperventilation, and ultimately generalized seizures and cardiogenic pulmonary edema. In this study, we have tested the hypothesis that changes in electrodermal activity (EDA), a measure of sympathetic nervous system activation, precedes seizures in rats breathing 5 atmospheres absolute (ATA) HBO2. Radio telemetry and a rodent tether apparatus were adapted for use inside a sealed hyperbaric chamber. The tethered rat was free to move inside a ventilated animal chamber that was flushed with air or 100% O2. The animal chamber and hyperbaric chamber (air) were pressurized in parallel at ~1 atmosphere/min. EDA activity was recorded simultaneously with cortical electroencephalogram (EEG) activity, core body temperature, and ambient pressure. We have captured the dynamics of EDA using time-varying spectral analysis of raw EDA (TVSymp), previously developed as a tool for sympathetic tone assessment in humans, adjusted to detect the dynamic changes of EDA in rats that occur prior to onset of CNS-OT seizures. The results show that a significant increase in the amplitude of TVSymp values derived from EDA recordings occurs on average (±SD) 1.9 ± 1.6 min before HBO2-induced seizures. These results, if corroborated in humans, support the use of changes in TVSymp activity as an early “physio-marker” of impending and potentially fatal seizures in divers and patients.

Current Probes for Imaging Carbonylation in Cellular Systems and Their Relevance to Progression of Diseases.

Oxidative stress resulted from reactive oxygen or nitrogen species in biological systems has a significant role in the diagnosis/progression of several human diseases. Human diseases associated with oxidative stress include Alzheimer's disease, chronic lung disease, chronic renal failure, cancer, diabetes, and fibrosis. In oxidative stress conditions, carbonylation process can be described as one of the most common modifications in biomolecules that takes place in the presence of carbonyl (C = O) groups which are introduced into molecules by direct metal-catalyzed oxidation of certain amino acids or indirectly by reaction with the oxidation of lipids and sugars. At a molecular cellular level, carbonylation can cause some defective biological consequences or chemical transformations in cells. During this process, specifically, carbonylated proteins can be accumulated in cells and trigger to develop some diseases in human body. The role of the accumulation of carbonylated proteins in the progression of several diseases has also been reported in the literature, such as neurodegenerative diseases, diabetes, obesity, aging, and cancer. Early detection of carbonylation process is, therefore, very critical to monitor these diseases at an early stage. Finding a suitable biomarker or probe is very challenging due to the need for multiple criteria: high fluorescence efficiency, stability, toxicity, and permeability. If they are designed with a good strategy, these probes are highly effective in cell biology applications and they can be used as good diagnostic tools for monitoring oxidative stress-induced carbonylation in relevant diseases. This review highlights the design and use of recent fluorescent probes for visualization of carbonylation in cellular systems and the relationship between oxidative stress and carbonyl species for causing long-term disease complications.

Beneficial Effects of a Combination of Curcuma longa L. and Citrus junos Against Beta-Amyloid Peptide-Induced Neurodegeneration in Mice.

Both Curcuma longa (CL) and Citrus junos Tanaka (CJ) have been used to treat various diseases due to their anti-inflammatory and antioxidative stress activities. In this study, we investigated the ameliorative effect of the combination of CL extract and CJ extract (CCC) against beta-amyloid (Aβ) peptide-induced neurological damage. CCC prevented neurocytotoxicity in vitro. In addition, it was confirmed that abnormal alternation behavior and memory impairment caused by Aβ peptide were reversed by treatment with CCC. Furthermore, CCC treatment led to recovery of the cholinergic system and reactive oxygen species (ROS) oxidative damage defense system. CCC induced expressions of cyclic-adenosine monophosphate response element-binding protein (CREB)-responsive element-binding protein and brain-derived neurotrophic factor were confirmed as was the significantly improved processing in the hippocampus of the mouse Aβ peptides. Accordingly, these results suggest that CCC can prevent and/or reverse neurocytotoxicity and cognitive deficits in a mouse model of Alzheimer's disease.

Oxygen Delivery With an Open Oxygen Mask and Other Conventional Masks: A Simulation-Based Study.

A recently introduced open oxygen mask design was marketed in 2021 (open mask A). The manufacturer claims that the mask "…provides one solution for all your oxygen delivery needs across your patients' continuum of care." The new oxygen mask specifies flow (1-15 L/min and flush) with an expected FIO2 from 0.25-0.85. This suggests that this mask eliminates the need for multiple oxygen delivery devices as FIO2 requirements change. This study aimed to describe the FIO2 performance of the new open oxygen mask and other commonly used oxygen masks. The following oxygen masks were studied: open mask A, open mask B, simple mask, partial rebreather, and non-rebreather. An adult mannequin head was attached to a breathing simulator, which recorded FIO2 at the simulated alveolar level. The simulator was set to a closed-loop volume control mode: VT = 320 mL, compliance = 50 mL/cm H2O, resistance = 4 cm H2O/L/s, breathing frequency = 15 breaths/min, increase = 25%, hold = 0%, and release = 30%. Oxygen was run through each mask at the recommended flows. Each flow was verified with a flow analyzer before attaching the mask for oxygen measurement. Each experiment was performed twice. The FIO2 measurements were averaged and compared using a 2-way ANOVA with P < .05 indicating significance. The FIO2 delivery was significantly different for each device. The measured FIO2 range was open mask A, 0.30-0.60; open mask B, 0.28-0.64; simple mask, 0.55-0.73; partial non-rebreather, 0.73-1.0; non-rebreather, 0.93-1.00. The performance of each oxygen mask from highest to lowest FIO2 : non-rebreather, partial rebreather, simple mask, open mask A, and open mask B. These findings suggest that no oxygen mask tested serves as a substitute for the others across a flow range of 1-15 L/min and flush.

Effect of Al2O3 on the molten slag microstructure information by molecular dynamics simulation and experimental analysis

The metallurgical properties of blast furnace slag changed when high alumina iron ore was used extensively due to the resulting changes of the molten slag microstructure. In the study, based on typical CaO–MgO–SiO2–Al2O3 slag systems with different w(Al2O3) content, molecular dynamics simulation was used to calculate the microstructural properties of particles in the high-temperature slag system, such as bond length, partial radial distribution function, coordination numbers, and diffusion coefficient. In addition, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and 27Al solid-state magic angle spinning nuclear magnetic resonance (27Al SS MAS NMR) were used to detect and analyze the samples. The comprehensive calculations and experimental results show that increasing w(Al2O3) can enhance the structural stability of each ion pair, and the strength of the structural stability is such that Si–O > Al–O > Mg–O > Ca–O. The self-diffusion coefficients are as follows: Mg2+ > Ca2+ > Al3+ > Si4+, which leads to the transformation of the [SiO4]4−(Q0), [Si2O7]6−(Q1) and [Si2O6]4−(Q2) structural units to [Si2O5]2−(Q3). The degree of polymerization of slag increased as well as the stability of the structural units. Moreover, the coordination of Al will change from the [AlO6]9−octahedral structure of six-coordinated Al to the [AlO5]7−pentahedral structure of five-coordinated Al and the [AlO4]5−tetrahedral structure of four-coordinated Al. It was also found that the content of non-bridge oxygen in the whole slag system decreased continuously, leading to the increasing degree of polymerization of slag, and the experimental results were consistent with the molecular dynamics calculation.

Common Uses and Adverse Effects of Hyperbaric Oxygen Therapy in a Cohort of Small Animal Patients: A Retrospective Analysis of 2,792 Treatment Sessions.

Hyperbaric oxygen therapy (HBOT) is commonly utilized for various human conditions with a low incidence of major adverse effects (0.002–0.035%). Despite growing use in veterinary patients, there remains a paucity of literature describing its use and associated complications. The purpose of this study was to report clinical use of HBOT in small animals and identify the rate of major adverse events at a university teaching hospital. Electronic medical records were searched for small animals receiving HBOT between November 2012 and February 2020. Data extracted from the medical records included signalment, treatment indication, and adverse events. Treatment sessions totaled 2,792 in 542 dogs, 24 cats, and 10 pocket pets and exotics. Common indications included neurologic injuries (50.4%), tissue healing (31.4%), control of oomycete infection (5.5%), neoplasia or post-radiation injury (5.4%), and various miscellaneous conditions (7.4%). Observed minor adverse events included agitation in two dogs and vomiting in three dogs. The most common major adverse event was central nervous system (CNS) oxygen toxicity in 19 dogs. Central nervous system oxygen toxicity, manifesting as focal or generalized seizures, occurred in 0.7% of treatment sessions, with increasing age (p = 0.01) and female sex (p = 0.01) identified as risk factors. One dog developed pulmonary edema following HBOT which is a reported adverse event in humans or may have been a manifestation of progression of the dog's underlying disease. No adverse events were noted in cats or other species. In conclusion, HBOT appeared safe across various indications, although oxygen toxicity affecting the CNS was higher than reports in humans. Future prospective, randomized, controlled trials should evaluate specific clinical indications and outcomes.

Time-varying Spectral Index of Electrodermal Activity to Predict Central Nervous System Oxygen Toxicity Symptoms in Divers: Preliminary results.

The most effective method to mitigate decompression sickness in divers is hyperbaric oxygen (HBO2) pre-breathing. However, divers breathing HBO2 are at risk for developing central nervous system oxygen toxicity (CNS-OT), which can manifest as symptoms that might impair a diver's performance, or cause more serious symptoms like seizures. In this study, we have collected electrodermal activity (EDA) signals in fifteen subjects at elevated oxygen partial pressures (2.06 ATA, 35 FSW) in the "foxtrot" chamber pool at the Duke University Hyperbaric Center, while performing a cognitive stress test for up to 120 minutes. Specifically, we have computed the time-varying spectral analysis of EDA (TVSymp) as a tool for sympathetic tone assessment and evaluated its feasibility for the prediction of symptoms of CNS-OT in divers. The preliminary results show large increase in the amplitude TVSymp values derived from EDA recordings ~2 minutes prior to expert human adjudication of symptoms related to oxygen toxicity. An early detection based on TVSymp might allow the diver to take countermeasures against the dire consequences of CNS-OT which can lead to drowning.Clinical Relevance-This study provides a sensitive analysis method which indicates a significant increase in the electrodermal activity prior to human expert adjudication of symptoms related to CNS-OT.

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions.

Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement in the pathophysiology of inflammatory diseases, metabolic disorders, and neurological defects. Free radicals increase the concentration of reactive oxygen and nitrogen species in the biological system through different endogenous sources and thus increased the overall oxidative stress. An increase in oxidative stress causes cell death through different signaling mechanisms such as mitochondrial impairment, cell-cycle arrest, DNA damage response, inflammation, negative regulation of protein, and lipid peroxidation. Thus, an appropriate balance between free radicals and antioxidants becomes crucial to maintain physiological function. Since the 1brain requires high oxygen for its functioning, it is highly vulnerable to free radical generation and enhanced ROS in the brain adversely affects axonal regeneration and synaptic plasticity, which results in neuronal cell death. In addition, increased ROS in the brain alters various signaling pathways such as apoptosis, autophagy, inflammation and microglial activation, DNA damage response, and cell-cycle arrest, leading to memory and learning defects. Mounting evidence suggests the potential involvement of micro-RNAs, circular-RNAs, natural and dietary compounds, synthetic inhibitors, and heat-shock proteins as therapeutic agents to combat neurological diseases. Herein, we explain the mechanism of free radical generation and its role in mitochondrial, protein, and lipid peroxidation biology. Further, we discuss the negative role of free radicals in synaptic plasticity and axonal regeneration through the modulation of various signaling molecules and also in the involvement of free radicals in various neurological diseases and their potential therapeutic approaches. The primary cause of free radical generation is drug overdosing, industrial air pollution, toxic heavy metals, ionizing radiation, smoking, alcohol, pesticides, and ultraviolet radiation. Excessive generation of free radicals inside the cell R1Q1 increases reactive oxygen and nitrogen species, which causes oxidative damage. An increase in oxidative damage alters different cellular pathways and processes such as mitochondrial impairment, DNA damage response, cell cycle arrest, and inflammatory response, leading to pathogenesis and progression of neurodegenerative disease other neurological defects.

Electrochemical laser induced graphene-based oxygen sensor

• Highly sensitive DO biosensor based on LIG decorated with co-Pt. • Enriched layer of metallic Pt nanostructures on graphene composite detected by SEM. • Synergistic response to DO in H9C2 cell culture. • Extended linear dynamic range 30 µM to 400 µM and fast response time of 2 s. • Synergy of electrochemistry and SEM and XPS analyses to investigate surface modifications. A fully integrated dissolved oxygen (DO) sensor was fabricated using laser induced graphene (LIG). The LIG was patterned on polyimide (Kapton) film using CO 2 laser followed by the electrodeposition of colloidal platinum to form the electroactive sensing area. The sensing area was insulated in an oxygen gas permeable membrane for selective detection of DO. The fabricated sensor demonstrated excellent catalytic activity towards the reduction of oxygen with a sensitivity of 246.66 µA/mMcm 2 over a linear detection range of 30 µM to 400 µM. The sensor exhibited a limit of detection (LOD) of 2.4 µM DO and fast response time of 2 s. The LIG-based DO sensor also exhibited good selectivity and stability. The sensor was further evaluated in a cell culture system to monitor DO to maintain cell culture viability. The DO sensor showed good performance in detecting oxygen in fresh medium (82.2 µM), at 80% cell confluency (102.37 µM), and at 100% confluency (93.52 µM). The performance of the DO sensor offers great promise for detecting dissolve oxygen in cell culture systems for biomedical and environmental applications.

Boron nanosheets induced microstructure and charge transfer tailoring in carbon nanofibrous mats towards highly efficient water splitting

Development of metal-free carbon-based electrocatalysts with high-efficiency and excellent durability towards both oxygen and hydrogen evolution reactions (OER and HER) in a single electrolyte system is crucial yet challenging for sustainable energy generation. In this work, we report a facile and scalable strategy for fabricating self-supporting boron carbon oxynitride nanofibrous (BCNONF) mats with controllable boron contents via electrospinning and subsequent thermal treatment. Notably, the optimal BCNONF mat affords outstanding OER performance in alkaline electrolyte with low overpotential of 403 mV at 10 mA·cm−2, small Tafel slop of 72.9 mV·dec−1, and high stability (88.1% current density retention after 10 h), outperforming the commercial Ir/C benchmark. Moreover, it can serve as a remarkable HER catalyst with better stability than that of the commercial Pt/C counterpart in the same electrolyte, indicating its bifunctional characteristics. When employed as both anode and cathode of an electrolyzer, the self-supporting BCNONF mats exhibit superior activities with a potential of only 1.79 V at 10 mA·cm−2 and high long-term durability (90.6% current density retention after 50 h) for overall water splitting. Furthermore, density functional theory (DFT) calculations reveal that the remarkable OER and HER bifunctional performance of the BCNONF catalyst are originated from the reduced adsorption strength of O atom and the stronger H* adsorption on the BCNO surface as compared to those on CNO surface, which in turn facilitate efficient interfacial charge transfer between the electrocatalytic intermediates and the BCNONF catalyst.

78 Physiologic Monitoring for Central Nervous System Oxygen Toxicity in Working Divers

The risk of central nervous system oxygen toxicity (CNSOT) limits diving operations for US Navy and occupational divers. CNSOT has variable and potentially deadly consequences such as seizures while underwater. Its pathophysiology is incompletely understood and its only current mitigation strategy is adhering to oxygen partial pressure (PO2) and time limits. Nutritional ketosis (NK) is used in the treatment of refractory epilepsy, and animal studies suggest it may delay onset of CNSOT. Primary objectives of this analysis are to better understand the pathophysiology and manifestations of CNSOT, and identify possible practical warning methods.

Design and analysis of a mechanical ventilation system based on cams

Low-cost mechanical ventilators have been developed in order to deal with the shortage of traditional ventilators whose quantity is not sufficient in an emergency context in Perú. Protofy, a company from Spain, designed one of the first low-cost mechanical ventilation systems OxyGEN which was approved by a medicine agency in its country in special context of COVID 19. Therefore, as main of this article, a redesign of this system named OxygenIP.PE was carried out according to local requirements and available technology, but maintaining its working concept based on compression mechanism by cams. Sensors were added and a control algorithm of the respiratory rate was developed. Ventilation curves monitoring over time was implemented; in this sense, a mathematical model of the whole system was developed. OxygenIP.PE was redesigned, fabricated, and tested measuring its ventilation curves over time. Results indicate that this redesign provides a sturdy equipment able to work during a longer lifetime than the original. The replicability of the ventilation curves behavior is ensured, while the mechanism dimensions are adapted for a particular airbag resuscitator. The mathematical model of the whole system can satisfactorily determine the ventilation curves over time and is used to show the air pressure, volume, and flow as a function of the compression arm's angular position and differential pressure through the breathing circuit measurement, furthermore the algorithms designed as a consequence of the mathematical model were implemented for Raspberry and ARDUINO microcontrollers. There were obtained parameters of pressure 10–65 cmH2O, airflow 50–65 l/m, volume 0–0.5 l, at two values of beat per minute (BPM) 15 and 25.

Review: Nanomaterials for Reactive Oxygen Species Detection and Monitoring in Biological Environments.

Reactive oxygen species (ROS) and dissolved oxygen play key roles across many biological processes, and fluorescent stains and dyes are the primary tools used to quantify these species in vitro. However, spatio-temporal monitoring of ROS and dissolved oxygen in biological systems are challenging due to issues including poor photostability, lack of reversibility, and rapid off-site diffusion. In particular, ROS monitoring is hindered by the short lifetime of ROS molecules and their low abundance. The combination of nanomaterials and fluorescent detection has led to new opportunities for development of imaging probes, sensors, and theranostic products, because the scaffolds lead to improved optical properties, tuneable interactions with cells and media, and ratiometric sensing robust to environmental drift. In this review, we aim to critically assess and highlight recent development in nanosensors and nanomaterials used for the detection of oxygen and ROS in biological systems, and their future potential use as diagnosis tools.

The effect of oxygen on in-situ evolution of chemical structures during the autothermal process of tobacco

Autothermal process which involves the introduction of oxygen to the pyrolysis process has been regarded as a better option for commercialization of biomass pyrolysis technologies. The presence of oxygen in the pyrolysis system will inevitably affect the thermal decomposition process, especially the release of products. However, few attentions have been paid to the influence of oxygen on in-situ evolution of chemical structure and emission of different product as pyrolysis process proceeded which are helpful for us to understand the role played by oxygen. Herein, we systematically demonstrated the effect of oxygen on the thermal decomposition of tobacco, a special lignocellulosic biomass material. The influential mechanisms of oxygen on the thermal decomposition process were explored via a series of in-situ characterization techniques including in-situ DRIFTS, in-situ XPS, Raman, and TG-MS. We found that the presence of oxygen was beneficial to oxygen and hydrogen removal process (e.g., dehydration, decarboxylation and de-carbonylation) during biomass pyrolysis, thus promoting the generation of aromatic char structure. In addition, the char formed under oxygen exhibited a more ordered structure with the larger aromatic crystallite size. Oxygen influenced the relative content of volatile and semi-volatile products, despite not affecting their types.

A novel hybrid model for water quality prediction based on synchrosqueezed wavelet transform technique and improved long short-term memory

Predicting water quality accurately is of utmost importance in water resource management. This study focuses on the prediction of water quality parameters such as the dissolved oxygen (DO) in the watershed system. The traditional recurrent neural networks (RNNs) suffer from gradient disappearance or explosion and inability to solve the problem of long-time dependence, and their practical applications are limited. To overcome this drawback, an improved long short-term memory (LSTM) model was proposed to improve the model’s performance. In addition, to overcome nonstationarity, randomness, and nonlinearity of the water quality parameters data, a hybrid model that recruits synchrosqueezed wavelet transform (SWT) to denoise the original data was adopted. A novel metaheuristic optimization algorithm, the improved sparrow search algorithm (ISSA) combining Cauchy mutation and opposition-based learning (OBL) was also implemented to compute the optimal parameter values for the LSTM model. The proposed hybrid model was evaluated using an original weekly water quality parameters series, from 1/2010–12/2016, measured at the Yongding River and Gangnan gauging stations in the Haihe River Basin, China. The standalone LSTM, ISSA-LSTM, SWT-LSTM, support vector regression (SVR), and back propagation neural network (BPNN) were adopted as comparative forecast models using the same dataset. The results demonstrate that the addressed model, combining the strong noise-resistant robustness of the SWT and the nonlinear mapping of the LSTM, has the best prediction performance among the peer models at two gauging stations. The proposed hybrid model can be used as an alternative framework for water quality prediction, which can provide decision-making basis for comprehensive water quality management and pollutant control in the basin.

ITRAQ-based proteomic analysis of sperm reveals candidate proteins that affect the quality of spermatozoa from boars on plateaus

BackgroundTibetan pigs (TP) exhibit heritable adaptations to their hypoxic environments as a result of natural selection. However, candidate proteins that affect the sperm quality of boars on plateaus have not yet been clearly investigated.MethodsIn this study, to reveal the candidate proteins that affect the quality of spermatozoa of boars on plateaus, we analyzed the sperm quality using computer-assisted semen analysis (CASA) system and reactive oxygen species (ROS) levels. We also compared the proteomes of sperm proteomes between TP and Yorkshire pigs (YP) raised at high altitudes using the isobaric tags for relative and absolute quantitation (iTRAQ) in combination with the liquid chromatography-tandem mass spectrometry (LC–MS/MS) proteomic method, and confirmed the relative expression levels of the four proteins by western blotting.ResultsThe sperm quality of the TP was superior to that of the YP on plateaus. Of the 1,555 quantified proteins, 318 differentially expressed proteins (DEPs) were identified. Gene ontology (GO) analysis revealed that the DEPs were predominantly associated with the sorbitol metabolic process, removal of superoxide radicals, cellular response to superoxide, response to superoxide and regulation of the mitotic spindle assembly. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were mainly enriched in pathways involved in the regulation of the actin cytoskeleton, glutathione metabolism, oxidative phosphorylation, and estrogen signaling. Based on the protein–protein interaction (PPI) network analysis, we identified 8 candidate proteins (FN1, EGF, HSP90B1, CFL1, GPX4, NDUFA6, VDAC2, and CP) that might play important roles and affect the sperm quality of boars on plateaus. Moreover, the relative expression levels of four proteins (CFL1, EGF, FN1, and GPX4) were confirmed by western blot analysis.ConclusionsOur study revealed 8 candidate proteins (FN1, EGF, HSP90B1, CFL1, GPX4, NDUFA6, VDAC2, and CP) that affect the sperm quality of boar on plateaus and provide a reference for further studies on improving sperm quality and the molecular breeding of boars on plateaus.