Saturated O2 Research Articles

Localized mammary gland changes in milk composition and venous blood metabolite concentrations result from sterile subclinical mastitis

Subclinical mastitis reduces milk yield and elicits undesirable changes in milk composition, but the mechanisms resulting in reduced milk production in affected mammary glands are incompletely understood. This study investigated the effects of sterile inflammation on mammary gland metabolism by assessing changes in milk and venous blood composition. Mid-lactation primiparous Holstein cows (n = 4) had udder halves randomly allocated to treatments; quarters of 1 udder half were infused with 2 billion cfu of formalin fixed Staphylococcus aureus (FX-STAPH) and quarters of the opposite udder half infused with saline (SAL). Blood samples were collected from the right and left subcutaneous abdominal veins in 2.6 h intervals until 40 h post challenge and analyzed for blood gas and metabolite concentrations. Milk from FX-STAPH udder halves had significantly increased SCS by first milking at 8 h post-challenge. By 16 h post-challenge, FX-STAPH udder halves had increased concentrations of protein and lactate and lower lactose concentrations than SAL udder halves. Milk fat concentrations, milk yields, energy corrected milk yields, and the ferric reducing antioxidant power of milk were not significantly different between SAL and FX-STAPH udder halves. Venous blood of FX-STAPH halves had marginally greater concentrations of saturated O2, partial pressures of O2, and glucose concentrations than SAL halves. Conversely, total and partial pressures of CO2 did not differ between udder half treatments suggesting a shift in local metabolite utilization in FX-STAPH udder halves. These results indicate that changes in milk composition resulting from mastitis are accompanied by changes in some key blood metabolite concentrations. The shift in venous blood metabolite concentrations, along with the marked increase in milk lactate, suggests that local mammary tissue and/or recruited and immune cells alters metabolite usage in mammary tissues. Future studies are needed to quantify the uptake of key milk precursors during mastitis.

Verification of Reinforced Surface Loose Layer of Zinc-Aluminum-Magnesium Steel Plate.

The corrosion resistance of zinc-aluminum-magnesium steel plates (Zn-Al-Mg steel plates) is significantly higher than that of galvanized steel plates. However, the unsatisfactory bonding performance of Zn-Al-Mg steel plates significantly limits their widespread application. In this study, X-ray photoelectron spectroscopy is employed to detect changes in the surface oxygen content of Zn-Al-Mg steel plates after different temperature treatments to confirm the existence of surface loose layers. In particular, changes in the surface oxygen content of the Zn-Al-Mg steel plates after the oxide layer is removed are investigated under saturated H2O vapor and O2 environmental conditions, and the cause of the formation of loose surface layers is determined. The uneven distribution of elements on the surface of the Zn-Al-Mg steel plates is investigated with scanning electron microscopy and energy dispersive spectroscopy. Nuclear magnetic resonance is employed to determine the size of the network spatial structure formed by silane coupling agents under different hydrolysis conditions and to further investigate the bonding performance of hydrolysate-modified Zn-Al-Mg steel plates. Several typical automotive adhesives are utilized to compare and examine the changes in the tensile strength of the Zn-Al-Mg steel plate bonding before and after modification with the silane coupling agent and analyze the structural damage of the adhesive at the bonding interface. The results confirm that the silane coupling agent strengthens the loose layer on the surface of the Zn-Al-Mg steel plate.

Investigation of molecular changes in wine during storage in refrigerated cabinets

Investigation of molecular changes in wine during storage in refrigerated cabinets

Anodal tDCS over the left DLPFC but not M1 increases muscle activity and improves psychophysiological responses, cognitive function, and endurance performance in normobaric hypoxia: a randomized controlled trial

BackgroundTranscranial direct current stimulation (tDCS) has been shown to have positive effects on exercise performance and cognitive function in the normal ambient condition. Hypoxia is deemed a stressful situation with detrimental effects on physiological, psychological, cognitive, and perceptual responses of the body. Nevertheless, no study has evaluated the efficacy of tDCS for counteracting the negative effects of hypoxic conditions on exercise performance and cognition so far. Hence, in the present study, we investigated the effects of anodal tDCS on endurance performance, cognitive function, and perceptual responses in hypoxia.Participants and methodsFourteen endurance-trained males participated in five experimental sessions. After familiarization and measuring peak power output in hypoxia, in the first and second sessions, through the 3rd to 5th sessions, participants performed a cycling endurance task until exhaustion after 30 min hypoxic exposure at resting position followed by 20 min of anodal stimulation of the motor cortex (M1), left dorsolateral prefrontal cortex (DLPFC), or sham-tDCS. Color-word Stroop test and choice reaction time were measured at baseline and after exhaustion. Time to exhaustion, heart rate, saturated O2, EMG amplitude of the vastus lateralis, vastus medialis, and rectus femoris muscles, RPE, affective response, and felt arousal were also measured during the task under hypoxia.ResultsThe results showed a longer time to exhaustion (+ 30.96%, p=0.036), lower RPE (− 10.23%, p = 0.045) and higher EMG amplitude of the vastus medialis muscle (+ 37.24%, p=0.003), affective response (+ 260%, p=0.035) and felt arousal (+ 28.9%, p=0.029) in the DLPFC tDCS compared to sham. The choice reaction time was shorter in DLPFC tDCS compared to sham (− 17.55%, p=0.029), and no differences were seen in the color-word Stroop test among the conditions under hypoxia. M1 tDCS resulted in no significant effect for any outcome measure.ConclusionsWe concluded that, as a novel finding, anodal stimulation of the left DLPFC might provide an ergogenic aid for endurance performance and cognitive function under the hypoxic condition probably via increasing neural drive to the working muscles, lowering RPE, and increasing perceptual responses.

Estimating benthic Fe and reactive solute fluxes

The flux of dissolved Fe (Fed) from sediments is a critical component of the biogeochemical Fe cycle. Common approaches to estimating these fluxes are based on modeling of Fed porewater profiles or incubating sediment and overlying water using benthic chambers or retrieved cores. Inadequate resolution of pore water Fe profiles in the uppermost mm of sediments and rapid Fe2+oxidation can greatly compromise these approaches. These limitations may be partially responsible for large variations in reported benthic Fed fluxes at given values of independent controlling variables such as sedimentary Corg remineralization rates. A series of laboratory experiments were conducted to compare methods to estimate Fe fluxes and confirmed that Fed2+ is oxidized to Fe3+ within a few minutes in oxygenated chamber water. The resulting Fe3+ colloids do not pass through 0.2 μm pore size filters and are also rapidly lost from suspension. Loss from suspension is partially reversible. Most benthic chamber studies do not correct for such losses and likely significantly underestimate Fed fluxes. Additional reactive components such as P and trace metals that associate with precipitated Fe-oxides must be subject to similar major losses during flux measurements. We modified the standard incubation methods by circulating overlying water through Fe extractors and accumulating Fed released into chambers over a known period at constant O2 and pH. We found using a range of experimental conditions that in cylindrical chambers ∼70–93% of introduced Fe2+ is typically recovered on accumulators at saturated O2 (∼270 μM) and seawater pH (∼8; NBS). We recommend that flux incubations that target reactive solutes (e.g., Fe, P) be configured with flow-through extractors, and pre-calibrated for losses specific to chamber designs, chamber water residence times, and deployment conditions (e.g., O2, pH).

Optical and chemical properties and oxidative potential of aqueous-phase products from OH and <sup>3</sup>C<sup>∗</sup>-initiated photooxidation of eugenol

Abstract. Aqueous reactions may turn precursors into light-absorbing and toxic products, leading to air quality deterioration and adverse health effects. In this study, we comprehensively investigated eugenol photooxidation (a representative biomass-burning-emitted, highly substituted phenolic compound) in the bulk aqueous phase with direct photolysis, a hydroxyl radical (OH), and an organic triplet excited state (3C∗). Results show that the degradation rates of eugenol followed the order of 3C∗> OH > direct photolysis. During the 3C∗-initiated oxidation, different reactive oxygen species (ROS), including 3C∗, OH, 1O2, and O2⚫-, can participate in the oxidation of eugenol, quenching experiments verified 3C∗ was the most important one, while, during OH-initiated oxidation, O2⚫- was a more important ROS than OH for degrading eugenol. The rate constants under saturated O2, air, and N2 followed the order of kO2>kAir>kN2 for both direct photolysis and OH-initiated oxidation but changed to kAir>kN2>kO2 for 3C∗-mediated oxidation. pH and dissolved oxygen (DO) levels both decreased during oxidation, indicating the formation of acids and the participation of DO in oxidation. Ultraviolet and visible (UV-vis) light absorption spectra of the reaction products showed a clear absorbance enhancement in the 300–400 nm range for all three sets of experiments, and new fluorescence at excitation/emission =250/ (400–500) nm appeared, suggesting the formation of new chromophores and fluorophores (brown carbon species). These species were likely attributed to humic-like substances (HULIS), as shown by the increases in HULIS concentrations during oxidation. Large mass yields of products (140 %–197 %) after 23 h of illumination were obtained, and high oxidation degrees of these products were also observed. Correspondingly, a series of oxygenated compounds were identified, and a detailed reaction mechanism with functionalization as a dominant pathway was proposed. At last, the dithiothreitol (DTT) assay was applied to assess the oxidation potential of the reaction products, and the end products of all three sets of experiments showed higher DTT consumption rates than those of eugenol, indicating that more toxic species were produced upon aqueous oxidation. Overall, our results from using eugenol as a model compound, underscore the potential importance of the aqueous processing of biomass burning emissions in secondary organic aerosol (SOA) formation.

Development and validation of models for two‐week mortality of inpatients with COVID‐19 infection: A large prospective cohort study

AbstractRecognizing COVID‐19 patients at a greater risk of mortality assists medical staff to identify who benefits from more serious care. We developed and validated prediction models for two‐week mortality of inpatients with COVID‐19 infection based on clinical predictors. A prospective cohort study was started in February 2020 and is still continuing. In total, 57,705 inpatients with both a positive reverse transcription‐polymerase chain reaction test and positive chest CT findings for COVID‐19 were included. The outcome was mortality within 2 weeks of admission. Three prognostic models were developed for young, adult, and senior patients. Data from the capital province (Tehran) of Iran were used for validation, and data from all other provinces were used for development of the models. The model Young, was well‐fitted to the data (p < 0.001, Nagelkerke R2 = 0.697, C‐statistics = 0.88) and the models Adult (p < 0.001, Nagelkerke R2 = 0.340, C‐statistics = 0.70) and Senior (p < 0.001, Nagelkerke R2 = 0.208, C‐statistics = 0.68) were also significant. Intubation, saturated O2 < 93%, impaired consciousness, acute respiratory distress syndrome, and cancer treatment were major risk factors. Elderly people were at greater risk of mortality. Young patients with a history of blood hypertension, vomiting, and fever; and adults with diabetes mellitus and cardiovascular disease had more mortality risk. Young people with myalgia; and adult patients with nausea, anorexia, and headache showed less risk of mortality than others.

Bilayer-passivated stable dif-TES-ADT organic thin-film transistors

The active region of organic thin film transistors (OTFTs) is usually sensitive to moisture and O2 in the air ambient, which hinders their practical applications. In this study, the effects of air ambient on characteristics of unpassivated 2,8-difluoro-5,11-bis (triethylsilylethynyl) anthradithiophene (dif-TES-ADT) OTFTs are clarified. The device is much more sensitive to H2O vapor than O2, although both of which cause TFT instability. To improve the environmental stability, inkjet-printed passivation of the fluoropolymer CYTOP and UV curing adhesive are compared. It is found that the CYTOP passivation is well compatible with the organic channel while the UV curing adhesive has excellent barrier ability to both H2O vapor and O2. Then CYTOP/UV adhesive bilayer passivation combining advantages of both materials is introduced to achieve stable operation of OTFTs, which can resist saturated H2O vapor and O2 for 25 days.

Heart Rate Variability and Its Associations with Organ Complications in Adults after Fontan Operation.

Reduction of heart rate variability (HRV) parameters may be a risk factor and precede the occurrence of arrhythmias or the development of heart failure and complications in people with postinfarct left ventricular dysfunction and after coronary artery bypass grafting. Data on this issue in adults after a Fontan operation (FO) are scarce. This study assessed the association between HRV, exercise capacity, and multiorgan complications in adults after FO. Data were obtained from 30 FO patients (mean age 24 ± 5.4 years) and 30 healthy controls matched for age and sex. HRV was investigated in all patients by clinical examination, laboratory tests, echocardiography, a cardiopulmonary exercise test, and 24-h electrocardiogram. The HRV parameters were reduced in the FO group. Reduced HRV parameters were associated with patients’ age at the time of FO, time since surgery, impaired exercise capacity, chronotropic incompetence parameters, and multiorgan complications. Univariate analysis showed that saturated O2 at rest, percentage difference between adjacent NN intervals of >50 ms duration, and peak heart rate were associated with chronotropic index. Multivariable analysis revealed that all three variables were independent predictors of the chronotropic index. The results of this study suggest novel pathophysiological mechanisms that link HRV, physical performance, and organ damage in patients after FO.

Structure and properties of nanocarbons-encapsulated WC synthesized by solution plasma process in palm oils

Palm oil is produced in the ASEAN region. The overhang of stocks, propellant fouling in the production process and used oils existed there. It is a crucial issue to make efficient use of such palm oils. Solution plasma process (SPP) is one step non-thermal plasma in the liquid phase. Our laboratory has already synthesized the nanocarbons materials, graphene, hetero-graphene from organic molecules by SP. Organic ones engineer these material sources. When the functionalized nanocarbon can be synthesized from natural products and their dust, the functionalized carbon materials are supplied by the green process and low price. We had already synthesized nanocarbons by SP from the palm oils. The nanocarbons were covered enhanced electrical conductivity of nanocarbons, which is referred to the nanocarbons-encapsulated WC (tungsten carbides). In this study, we aimed to evaluate the structure and the properties of nanocarbons-encapsulated WC to provide the nanocarbons-encapsulated. The solution plasma was generated by the bipolar pulsed power supply through two tungsten electrodes using 2 μs pulse widths and frequencies (100, 150, and 180 kHz) for 30 min. We found that the observed plasma types depended on the discharge conditions. Conversion percentage of the oil to WC-encapsulated nanocarbon (% yield) was increased with frequency. The obtained X-ray diffraction patterns are showed the crystalline structure. The morphology of nanocarbon capsules WC are spherical shapes and less than 10 nm size. The electrochemical properties indicate that the ORR activity in an acidic medium under saturated O2 significantly disappears in the case of the nanocarbon-encapsulated WC synthesised in the high frequency (180 kHz). The synthesized nanocarbons-encapsulated WC might be applied in data storage and energy applications.

Alternate routes to sustainable energy recovery from fossil fuels reservoirs. Part 1. Investigation of high-temperature reactions between sulfur oxy anions and crude oil

The world is undergoing a substantial transition in its energy supply. Examining the possibilities to recover and use fossil fuel energy without emitting carbon dioxide to the surface, H2S was considered as an alternative energy vector to deliver a carbon free fuel from petroleum reservoirs to the surface. In this study, we investigated the high P-T chemical oxidation of crude oil with a suite of inorganic sulfur compounds. Tested inorganic sulfur compounds can be ordered by their ability to promote chemical changes to the oil matrix with the concomitant production of hydrogen sulfide, with a reactivity series, listed in order of decreasing reactivity as: S0 > S2O32− ~ S4O62− > SO32− > SO42−. The reaction mechanisms proposed in the study also light on likely key intermediate reactants and the geological timescale process of thermochemical sulfate reduction. Polysulfide species (containing S-S bond structures), such as thiosulfate and tetrathionate, may be reactive intermediates during the redox reaction. However, the early stage of thermochemical sulfate reduction may also involve labile organic sulfur functional groups converting to more stable molecules with aromatic structural units, such as dibenzothiophenes (DBT) and benzonaphthothiophenes (BNT). The apparent formation of saturated fatty acids and O2, NO and NO2 aromatic heteroatom species indicates the oxidation of saturated and aromatic hydrocarbons or heteroatom compounds. The oxidation of aromatic species may lead to aromatic ring-opening, followed by decarboxylation forming CO2 as final products.

Comparative Photo-Electrochemical and Photocatalytic Studies with Nanosized TiO2 Photocatalysts towards Organic Pollutants Oxidation

The size of TiO2 can significantly affect both its photocatalytic and photo-electrochemical properties, thus altering the photooxidation of organic pollutants in air or water. In this work, we give an account of the photo-electrochemical and photocatalytic features of some nanosized TiO2 commercial powders towards a model reaction, the photooxidation of acetone. Cyclic voltammograms (CV) of TiO2 particulate electrodes under UV illumination experiments were carried out in either saturated O2 or N2 solutions for a direct correlation with the photocatalytic process. In addition, the effect of different reaction conditions on the photocatalytic efficiency under UV light in both aqueous and gaseous phases was also investigated. CV curves with the addition of acetone under UV light showed a negative shift of the photocurrent onset, confirming the efficient transfer of photoproduced reactive oxygen species (ROSs), e.g., hydroxyl radicals or holes to acetone molecules. The photocatalytic experiments showed that the two nano-sized samples exhibit the best photocatalytic performance. The different photoactivity of the larger-sized samples is probably attributed to their morphological differences, affecting both the amount and distribution of free ROSs involved in the photooxidation reaction. Finally, a direct correlation between the photocatalytic measurements in gas phase and the photo-electrochemical measurements in aqueous phase is given, thus evincing the important role of the substrate-surface interaction with similar acetone concentrations.

Converting Immune Cold into Hot by Biosynthetic Functional Vesicles to Boost Systematic Antitumor Immunity.

SummaryImmune cold tumor characterized by low immunogenicity, insufficient and exhausted tumor-infiltrating lymphocytes, and immunosuppressive microenvironment is the main bottleneck responsible for low patient response rate of immune checkpoint blockade. Here, we developed biosynthetic functional vesicles (BFVs) to convert immune cold into hot through overcoming hypoxia, inducing immunogenic cell death, and immune checkpoint inhibition. The BFVs present PD1 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the surface, whereas load catalase into their inner core. The TRAIL can specifically induce immunogenic death of cancer cells to initiate immune response, which is further synergistically strengthened by blocking PD1/PDL1 checkpoint signal through ectogenic PD1 proteins on BFVs. The catalase can produce O2 to overcome tumor hypoxia, in turn to increase infiltration of effector T cells while deplete immunosuppressive cells in tumor. The BFVs elicit robust and systematic antitumor immunity, as demonstrated by significant regression of tumor growth, prevention of abscopal tumors, and excellent inhibition of lung metastasis.

Photoinduced Field-Effect Passivation from Negative Carrier Accumulation for High-Efficiency Silicon/Organic Heterojunction Solar Cells.

Carrier recombination and light management of the dopant-free silicon/organic heterojunction solar cells (HSCs) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are the critical factors in developing high-efficiency photovoltaic devices. However, the traditional passivation technologies can hardly provide efficient surface passivation on the front surface of Si. In this study, a photoinduced electric field was induced in a bilayer antireflective coating (ARC) of polydimethylsiloxane (PDMS) and titanium oxide (TiO2) films, due to formation of an accumulation layer of negative carriers (O2- species) under UV (sunlight) illumination. This photoinduced field not only suppressed the silicon surface recombination but also enhanced the built-in potential of HSCs with 84 mV increment. In addition, this photoactive ARC also displayed the outstanding light-trapping capability. The front PEDOT:PSS/Si HSC with the saturated O2- received a champion PCE of 15.51% under AM 1.5 simulated sunlight illumination. It was clearly demonstrated that the photoinduced electric field was a simple, efficient, and low-cost method for the surface passivation and contributed to achieve a high efficiency when applied in the Si/PEDOT:PSS HSCs.

Evaluation of Order Mesoporous Carbon as Anode Catalyst for Microbial Fuel Cells Applications

Ordered Mesoporous Carbon (OMC) was evaluated as anode catalyst in a MFC. Bacilus subtilis (B. subtilis) was the microorganism, while the electrolyte was Pharmaceutical Residual Water (PRW). In a dual chamber MFC, the anode and cathode compartments contained N2–saturated PRW and O2–saturated KOH (both electrolytes with pH=9.6), respectively, separated by a Nafion® membrane. The anode catalysts on gas diffusion electrodes in the MFC were: methanol-functionalized OMC, non-functionalized OMC, methanol-functionalized Vulcan XC-72 and commercial Pt/C, all covered by a biofilm of B. Subtilis. Meanwhile, the cathode catalyst was Pt/C. Significantly higher catalytic activity was obtained from functionalized OMC + B. Subtilis in the MFC. The Open Circuit Voltage (OCV) was 0.58 V, with a maximum current density (jcell) of 854 mA m-2. These values were 2.6 and 4.7 times higher than those from Pt/C. The results showed that methanol-functionalized OMC is a metal-free catalyst with high performance for MFCs.

Facile Synthesis of Nano-Alloy Particles for the Oxygen Evolution Reaction

We report a facile method for the infiltration of late 3d transition metals into nanoporous carbon. This method allows for the deposition of Ni, Fe, and Co, as well as their binary alloys, NiFe, NiCo, and FeCo. Utilizing NH3-saturated water nanodroplets adsorbed within nanoporous carbon, metal precursors are precipitated as metal hydroxides with high dispersion. Following deposition, the MOx-carbon composites are reduced in 5% H2 atmosphere and then alloyed at 1100 °C in Ar. The resulting metal and alloy loaded carbon composites demonstrate excellent activity and stability for the alkaline oxygen evolution reaction (OER). The NiFe, and NiCo alloy composites both require an overpotential less than 400 mV after 2 hours under alkaline OER conditions in saturated O2.

Intraoperative Patterns of Gastric Microperfusion During Laparoscopic Sleeve Gastrectomy.

Laparoscopic sleeve gastrectomy (LSG) has become a very popular surgical treatment for the treatment of morbidly obese patients. Staple line leaks are the major cause of severe morbidity. Reasons for leaks might be hyperpressure (mechanical theory) or hypoperfusion (vascular theory) of the narrow gastric tube. This study assessed microperfusion patterns of the stomach during LSG using visible light spectroscopy (VLS), a method to measure tissue oxygenation (saturated O2 (StO2)). The study population comprised 20 patients undergoing LSG. Real-time intraoperative microperfusion measurements were performed at nine different ventral stomach localizations in the antrum, body, and fundus at the beginning of the operation, after mobilization of the greater curve and after sleeve resection. There were 17 women and 3 men, mean age 42.9years, mean BMI 45.6kg/m2. There were no staple line leaks. StO2% values dropped substantially in the most cephalad area of measurement at the greater curve after mobilization (56 versus 49%) and after resection (60 versus 49.5%). The reduction in StO2 in the most cephalad area from before mobilization of the stomach to resection was 9.5% (p<0.01). Assessment of microperfusion patterns of the stomach during LSG using VLS is safe and efficacious to use allowing an accurate measurement of StO2%. The upper third of the stomach is the zone of reduced microperfusion with a significant drop of tissue oxygenation after sleeve resection of the stomach.

Hydrothermal Synthesis of Co-N-C Nanocomposites As High Performance Electrocatalysts for Oxygen Reduction Reaction

With the dramatically increased market demands of new energy materials due to the development of a large number of electronic devices and environmental awareness of the awakening, catalysts for oxygen reduction reaction (ORR) which are the most critical parts for high energy capacity and cleaning power sources including fuel cells and metal-air batteries have attracted highly attention and intense researches recently. Despite massive efforts, developing catalysts of high efficiency, long-term durability and excellent methanol tolerance with low cost for ORR is still a big challenge. Pt and Pt–based alloys are still the best choices for catalyzing oxygen reduction process by now. However, their high cost, low abundance, inferior stability and declining activity hinder their large-scale uses in industry. Therefore, selecting alternative materials to replace Pt and improve its performance is of great concern. Chitosan, as the second most abundant biopolymer in nature, is rich in the outer shell of some arthropod (prawns, crabs, insects) and the inner shell and cartilage of mollusks (squid, cuttlefish) with some attractive properties, such as non-toxic, biocompatibility and safety, especially, its natural nitrogen rich, strong chelation effects, sustainable and environmental friendly and low cost depend that it can be heavy used to synthesize metal and nitrogen co-doped carbon (MNC) nanomaterials , which can provide an enhanced catalytic activities. In the present work, taking advantage of strong chelation effects between hydroxyl group and metal ions and abundant natural nitrogen of chitosan, we developed a novel Co and N co-doped carbon (Co-N-C) nanocomposites as high performance electrocatalysts for ORR by using a simple and facile hydrothermal method, followed by high-temperature calcination at inert gas atmosphere. This material shows a delectable catalytic activity compared to the commercial 20% Pt/C electrode in the alkaline solution for ORR with a relative positive onset potential of -0.045V (vs. Hg/HgO), a much improved by 16.7% current density than Pt/C (loading ~ 0.4mg/cm2) as well as excellent durability performance and superior methanol tolerance. In addition, the method we used in this research is also suitable for preparing other MNC, which demonstrates that we found a new, straightforward and low-cost way to synthesis a series of catalysts for ORR which are comparable to commercial Pt/C. Cyclic voltammetry (CV) was employed to test the ORR catalytic activity of Co-N-C-800 and the commercial 20% Pt/C catalyst in saturated O2 alkaline solution (0.1 M KOH) and shown in Figure 1a, an obvious cathodic peak can be found at -0.10 V vs. Hg/HgO which implies excellent ORR performance, and according to figure 1b, we can find that our Co-N-C-800 has a very close onset potential (-0.045V) and much higher current density (16.7% improved) in comparison to that of the commercial Pt/C, respectively, superior to the performances of pure chitosan without Co (C-800), which can confirm that Co-doping is crucial to the outstanding activity performance of Co-N-C-800. Owning to small metal nanocrystals of cobalt can improve the conductivity of materials and charge transfer efficiency between carbon and cobalt and give more active sites1. RDE measurements at various rotating speeds at a scan rate of 10 mV s-1 in O2-saturated solution were carried out for Co-N-C-800 and shown in Figure 1c. The current density shows a typical increase with rotation rate due to the shortened diffusion layer and the linearity of K-L plots for Co-N-C-800 indicates a good four-electron reaction path selectivity with the electron transfer numbers (n) is ≈ 3.9, which is close to that of Pt/C catalyst and further demonstrates an outstanding catalytic performance of this catalyst. Acknowledgments This work was financially supported by the Shenzhen Peacock Plan (KQCX20140522150815065), the Natural Science Foundation of Shenzhen (JCYJ20150331101823677) and the Science and Technology Innovation Foundation for the Undergraduates of SUSTC (2015x19 and 2015x12). Reference 1. Xie, S.; Huang, S.; Wei, W.; Yang, X.; Liu, Y.; Lu, X.; Tong, Y., Chitosan Waste-Derived Co and N Co-doped Carbon Electrocatalyst for Efficient Oxygen Reduction Reaction. ChemElectroChem 2015, 2 (11), 1806-1812. Figure 1

Improvement of the dielectric and ferroelectric properties of multiferroic Pb(Fe1/2Nb1/2)O3 ceramics processed in oxygen atmosphere

Multifunctional materials such as the multiferroic compound Pb(Fe1/2Nb1/2)O3, are of great interest from the academic and technological points of view. However, the occurrence of Fe2+ and oxygen vacancies originated during the sintering process increase the dielectric loss and electrical conductivity, detrimental to optimal device performance. Here, a report on the effects of a saturated O2 atmosphere used during the calcination and sintering stages is presented. A comparative study of structural, morphological, and physical properties with those obtained for samples sintered in air or in its own atmosphere, is presented. The O2 atmosphere enhances the dielectric constant by ~180 % (with maximum e r of 12700 at T C = 103 °C and dielectric loss smaller than 0.01 independent of frequency and temperature below 100 kHz and T C, respectively), the maximum and remanent polarization by ~275 % (P max from 6.2 to 16.8 µC/cm2 and P r from 2.4 to 6.7 µC/cm2 at 16 kV/cm), and reduces the electrical conductivity by one order of magnitude (from ~1 × 10−7 to ~3 × 10−8/Ω cm at 1 kHz at room temperature). Additionally, a pronounced ac positive temperature coefficient of resistivity effect, strongly dependent on frequency and with potential barrier values from 0.2 eV at 1 kHz to 0.71 eV at 500 kHz, is associated with the highly resistive and capacitive behavior of the grain boundary.

Effects of color temperatures (Kelvin) of LED bulbs on blood physiological variables of broilers grown to heavy weights

Light-emitting diode (LED) lighting is being used in the poultry industry to reduce energy usage in broiler production facilities. However, limited data are available comparing efficacy of different spectral distribution of LED bulbs on blood physiological variables of broilers grown to heavy weights (>3 kg). The present study evaluated the effects of color temperature (Kelvin) of LED bulbs on blood physiological variables of heavy broilers in 2 trials with 4 replicates/trial. The study was a randomized complete block design. Four light treatments consisted of 3 LED light bulbs [2,700 K, (Warm-LED); 5,000 K, (Cool-LED-#1); 5,000 K, (Cool-LED-#2)] and incandescent light (ICD, standard) from 1 to 56 d age. A total of 960 1-day-old Ross × Ross 708 chicks (30 males/room 30 females/room) were equally and randomly distributed among 16 environmentally controlled rooms at 50% RH. Each of the 4 treatments was represented by 4 rooms. Feed and water were provided ad libitum. All treatment groups were provided the same diet. Venous blood samples were collected on d 21, 28, 42, and 56 for immediate analysis of selected physiological variables and plasma collection. In comparison with ICD, Cool-LED-#1 had greater (P < 0.05) effects on pH, partial pressure of CO2 (pCO2), partial pressure of O2 (pO2), saturated O2 (sO2), and K+. However, all these acid–base changes remained within the normal venous acid–base homeostasis and physiological ranges. In addition, no effect of treatments was observed on HCO3−, hematocrit (Hct), hemoglobin (Hb), Na+, Ca2+, Cl−, mean corpuscular hemoglobin concentration (McHc), osmolality, and anion gap. Moreover, blood glucose concentrations were not affected by treatments. This study shows that the 3 LED light bulbs evaluated in this study may be suitable for replacement of ICD light sources in commercial poultry facilities to reduce energy cost and optimize production efficiency without inducing physiological stress on broilers grown to heavy weights.