Deoxygenation Rate Research Articles

Towards an Information System of Modeling and Monitoring of Cikapundung River, Bandung, Indonesia

Growing recognition of the need for water safety makes river water quality monitoring information and modelling usage more important to be accessed by many stakeholders. Cikapundung River which is located in the heart of Bandung City has its water for many purposes. In the other hand, the water of this river suffers as a result of wastes disposal from existing activities on its banks. Several agencies conduct regular monitoring, both discharge and water quality of this river. However, the monitoring results are not published openly. The data can only be obtained by visiting the monitoring agency. This procedure may result a non-optimal usage of the data, and can even be harmful when unsafe water is used for consumption need. An information system of monitoring data and modelling of Cikapundung River water quality is proposed to improve the method of data publication. Modelling of Cikapundung River water quality is also developed to have simple software for DO and BOD calculation simulation. The modelling is using Streeter-Phelps equation for DO calculation and first-order reaction of Phelps law for BOD calculation. The deoxygenation rates used in the software were obtained from the laboratory experiments, i.e. 0.01-0.37 per day.

Hydrodeoxygenation of fatty acid esters catalyzed by Ni on nano-sized MFI type zeolites

Nanosized MFI type zeolite stabilizes small Ni particles enhancing deoxygenation rates. Turnover frequencies, however, are independent of support morphology.

Co-Pyrolysis Behaviors of the Cotton Straw/PP Mixtures and Catalysis Hydrodeoxygenation of Co-Pyrolysis Products over Ni-Mo/Al2O3 Catalyst

The doping of PP (polypropylene) with cotton straw improved the bio-oil yield, which showed there was a synergy in the co-pyrolysis of the cotton straw and PP at the range of 380–480 °C. In a fixed-bed reactor, model compounds and co-pyrolysis products were used for reactants of hydrodeoxygenation (HDO) over Ni-Mo/Al2O3. The deoxygenation rate of model compounds decreased over Ni-Mo/Al2O3 in the following order: alcohol > aldehyde > acetic acid > ethyl acetate. The upgraded oil mainly consisted of C11 alkane.

Deoxygenation rate, reaeration and potential for self-purification of small tropical urban stream

Mathematical models used to simulate the water quality and the processes of self-purification of water bodies are important tools to support effective water resource management. The objective of this study was to evaluate the impact of organic pollution on water quality and the assimilative capacity of organic matter in the Ribeirao Vermelho stream situated in the city of Lavras in Minas Gerais. The deoxygenation rate (K1) and reaeration (K2) were determined and tested in three segments of the Ribeirao Vermelho over two seasons (summer and winter). The purification process simulation was performed using the Streeter- Phelps model. The highest K1 and K2 values occurred during the winter period which was characterized by lower flows. Simulation of the dissolved oxygen profile and biological oxygen demand fitted the model well, indicating the prevalence of carbonaceous deoxygenation due to nitrification and also demonstrating the importance of natural reaeration as part of the purification process. Different response was observed during the winter, in which the high primary productivity values stood in the reaeration process stream. Biological oxygen demand values did not meet the limits recommended by the Resolution of the Ministry of the Environment 357/2005 throughout the river system and the entire study period. In conclusion, the Ribeirao Vermelho is unable to self-purify along its entire length, and water quality is influenced by effluent discharge which intensifies degradation.

Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients

ObjectivesTo compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. DesignProspective and observational study. SettingIntensive care unit. SubjectsSeptic shock patients and healthy volunteers. InterventionsThe probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). VariablesBaseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. ResultsSeptic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (−0.54±0.31 vs. −0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63–0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results. ConclusionSeptic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2.

Influence on nickel particle size on the hydrodeoxygenation of phenol over Ni/SiO2

Hydrodeoxygenation (HDO) of phenol over nickel nano-particles of different size (5–22nm) supported on SiO2 has been investigated in a batch reactor at 275°C and 100bar. Deoxygenation was only observed as a consecutive step of initial hydrogenation of phenol at the given conditions. Both the hydrogenation and deoxygenation reaction were found to be Ni-particle size dependent. Rapid hydrogenation of phenol to cyclohexanol was achieved over the catalysts with large particles, while the rate of deoxygenation of cyclohexanol was slow. For the catalysts with small Ni particles, the opposite behavior was observed Specifically, the turn over frequency (TOF) of hydrogenation was 85 times slower for 5nm particles than for 22nm particles. On the contrary, the TOF of cyclohexanol deoxygenation increased by a factor of 20 when decreasing the particle size from 20nm to 5nm. A simple kinetic model showed that the rate limiting step for phenol HDO shifted from deoxygenation to hydrogenation when the particle size was below 9–10nm. Surface site population theory evidenced that the deoxygenation reactions were favored on step/corner sites, giving higher deoxygenation rates at small particles. For hydrogenation, the influence of particle size on the rate could be related to the size of the Ni facets with larger facets thus being better.

OP42 - Precision control of dissolved oxygen in mammalian cell culture media impacts on in situ volatile generation and promotes improved mesenchymal stem cell yield accompanied by reduced transcriptional variability

Mammalian cell culture is reliant on culture media to support in vitro growth and proliferation. Culture media contains salts, vitamins, and minerals at precise levels where subtle variations result in novel media formulations. Oxygen is a bioactive molecule which impacts strongly on intracellular signalling, mitochondrial function, and metabolic pathway choices. We sought to determine the levels of dissolved oxygen in cell culture media and to design systems to support precision control of those levels. Dissolved oxygen levels in culture media displayed substantial variability ranging from 6 – 11 mg/L (~10% O2 - 21% O2) in all medias tested (DMEM, MEM, IMDM). In addition to this variability it was apparent that deoxygenation of cell culture media required incubation in hypoxic (1% O2) environments for >24 hours. The deoxygenation process could be accelerated to 3 hours via a combination of cooling (4 °C), agitation, and provision of a hypoxic headspace (1% O2, 5% CO2). Deoxygenation rates were volume dependent but were significantly more rapid than passive approaches. Selected Ion Flow Tube (SIFT)- MS) was then used to measure changes in volatile organic compound (VOCs) in media incubated overnight in either 21% O2, 2% O2, and 2% O2 following rapid deoxygenation. Reduced variation was apparent in pre-deoxygenated media where reduced standard deviations revealed significant differences to base media in 40% of VOCs tested. Finally we sought to determine the impact of pre-deoxygenated media on clonogenicity and transcriptome of MSCs isolated from fresh marrow. Precision deoxygenation (2% O2) of culture media associated significantly with increased yields of MSCs. Microarray analysis of MSCs isolated in all conditions further demonstrated reduced variability in global transcriptome where differentially expressed transcripts associated strongly with defined pathways. In summary precision control of dissolved O2 levels reduces media-based chemical reaction variability and promotes enhanced cell isolation from primary materials.

Journal of clinical monitoring and computing 2014 end of year summary: near infrared spectroscopy (NIRS).

Near infrared spectroscopy (NIRS) is a non-invasive method for monitoring hemoglobin oxygen saturation within the microvessels. It is therefore also sometimes (erroneously) referred to as a measure of tissue oxygenation. By using self-adhesive optodes on the body surface, measurements can be taken in tissues below the skin up to a depth of 3–4 cm. The near infrared light (unlike visible light) even penetrates bone tissue, allowing measurement of regional cerebral oxygenation (SrcO2). There are numerous devices using NIRS technology available on the market, and the main applications for use include monitoring of SrcO2 during cardiothoracic and vascular (particularly carotid artery) surgery, as well as non-cardiac surgery that is performed in the sitting or so-called beach chair position [1]. Another widespread use is the assessment of SrcO2 in neonates and preterm infants [2]. Furthermore, there have been attempts to use peripheral tissue oxygenation (SptO2) measurements by NIRS for guiding therapy and predicting outcome in emergency medicine (both pre-hospital and emergency room use) and in the perioperative setting [3]. Finally, the ability to measure SptO2 at different sites [4] raised interest in researchers to look at physiological changes, e.g. during exercise, in musculature of the leg or arm. For this, a special provocation test (the vascular occlusion test (VOT) by inflating a tourniquet proximal to the measurement site) has been developed. The VOT looks at the rate of deoxygenation during ischemia (vascular occlusion), which is considered as a measure of muscle and mitochondrial oxygen consumption, and at the rate of reoxygenation during reperfusion, reflecting the reactivity of the microcirculation [5]. The Journal of Clinical Monitoring and Computing (JCMC) has become an ideal platform for publishing NIRS-related research, as reflected by an increasing number of articles published in the recent years. This article will review two papers on peripheral (SptO2) and two papers on cerebral hemoglobin oxygen saturation (SrcO2) published last year in the JCMC.

Modelling Effluent Assimilative Capacity of Ikpoba River, Benin City, Nigeria

The sheer display of reprehensible propensity on the part of public hospitals, abattoirs, breweries and city dwellers at large to discharge untreated waste, debris, scum and, in particular, municipal and industrial effluents into Ikpoba River has morphed into a situation whereby the assimilative capacity of the river has reached a record level. The seeming quietism and clinical posture of the relevant Environmental Agency to this pathological condition is sickening and in any case seen as remiss on their part. This paper seeks to determine the assimilative capacity of the river with a view to articulating policy-proposal stream in the instance that its value is unsafe for ichthyofaunal beings and humans. A combination of basic Streeter-Phelp equation and monograph of Fair et al. were used for the determination of the assimilative capacity and the maximum allowable biological oxygen demand (BOD) load discharged into the river from three identified point sources of wastewater and for three different seasons in Nigeria (i.e. rainy, dry and harmattan seasons). Results indicate that in all the segments studied, the Fair ratio (self-purification factor) is less than unity, indicating the predominance of deoxygenation rate over reaeration rate. Reaeration rate ranges over all real values from 0.641day- 1 to 0.693day- 1 , while deoxygenation rate ranges between 0.718 day- 1 and 0.839 day -1 ; a condition which indicates a poor assimilative capacity potential. Moreover, a higher assimilative capacity was obtained for rainy season for all the segments studied, with sampling point 3 (Guinness-harmattan and dry season) showing an overall worse assimilative capacity and poor maximum allowable BOD of 8.1x10 9 , 1.28x10 10 and 5.60x10 9 kg/day respectively. In a way, the determination of the assimilative capacity of Ikpoba River is a landmark in the history of the river pollution. It beggars belief that we live down the harrowing pathological condition of the river without recognizing its wider implications. http://dx.doi.org/10.4314/njt.v34i1.17

Triglycerides Catalytic Hydroconversion into Bio-Aviation Fuels Based on Temperature by One-Step

One-step hydrotreatment of three different vegetable oils have been carried out over Pd loading bi-functional catalyst in batch reactor. Rubber seed oil, Jatropha oil and castor oil have different acid value and constituents, which will influence the hydroprocessing and the quality of products. With temperature rising, several principles have been summarized, and an optimal temperature corresponding to three oils have been determined respectively. At the optimal temperature of Jatropha oil, 300°C, deoxygenation rate was up to 99.29%, C8-16hydrocarbons of products was up to 77.36%; 310°C and 320°C were respectively optimal temperature of rubber seed oil and castor oil, deoxygenation rate were 99.15% and 98.78%, C8-16hydrocarbons were 71.46% and 69.25%. The products quality of Jatropha oil was better than rubber seed oil and castor oil, and rubber seed oil and castor oil can cause the deactivation of catalyst.

I/Ca evidence for upper ocean deoxygenation during the PETM

AbstractAnthropogenic global warming affects marine ecosystems in complex ways, and declining ocean oxygenation is a growing concern. Forecasting the geographical and bathymetric extent, rate, and intensity of future deoxygenation and its effects on oceanic biota, however, remains highly challenging because of the complex feedbacks in the Earth‐ocean biota system. Information on past global warming events such as the Paleocene‐Eocene Thermal Maximum (PETM, ~55.5 Ma), a potential analog for present and future global warming, may help in such forecasting. Documenting past ocean deoxygenation, however, is hampered by the lack of sensitive proxies for past oceanic oxygen levels throughout the water column. As yet no evidence has been presented for pervasive deoxygenation in the upper water column through expansion of oxygen minimum zones (OMZs). We apply a novel proxy for paleoredox conditions, the iodine to calcium ratio (I/Ca) in bulk coarse fraction sediment and planktonic foraminiferal tests from pelagic sites in different oceans, and compared our reconstruction with modeled oxygen levels. The reconstructed iodate gradients indicate that deoxygenation occurred in the upper water column in the Atlantic, Indian Oceans, and possibly the Pacific Ocean, as well during the PETM, due to vertical and potentially lateral expansion of OMZs.

Multiproxy geochemical analysis of a Panthalassic margin record of the early Toarcian oceanic anoxic event (Toyora area, Japan)

The early Toarcian oceanic anoxic event (OAE) was a significant palaeoenvironmental perturbation that led to marked changes in ocean chemistry and climate, and which also had a long-lasting impact on marine ecosystems. The global significance of the event has been recognised from the widespread occurrence of a ~3–7‰ negative excursion in the carbon-isotope (δ13C) composition of marine organic and inorganic matter and terrestrial plant material. This feature of the event is indicative of a pronounced perturbation to the global carbon cycle; an inference further supported by widespread evidence for seawater deoxygenation and elevated rates of organic carbon burial. Nevertheless, the precise palaeoenvironmental impacts of this event from sections outside of the Boreal and Tethyan realms are uncertain. Here, we present the results of a multiproxy geochemical study of an expanded record of the early Toarcian event from the northwest Panthalassa Ocean margin exposed in southwest Japan (Toyora area, Yamaguchi prefecture). Our results indicate that in the studied succession, organic matter enrichment persisted through the early Toarcian event, but elemental redox proxies do not support persistent seawater anoxia. Analyses of terrigenously derived major and trace element abundances coupled with sedimentological observations reveal an increase in coarse-grained sediment close to the onset of a ~−4‰ excursion in δ13Corg, and coincident with an inferred increase in terrestrial organic matter flux. These observations are consistent with previously published evidence for a marked strengthening of hydrological cycling and increased runoff that occurred contemporaneously with abrupt warming at the onset of the carbon isotope event.

Dose and wavelength dependent study of graphene oxide photoreduction with VUV Synchrotron radiation

Photoreduction has so far received less attention than other approaches used to reduce graphene oxide (GO) like thermal and chemical reduction, although its potential is huge. The mechanism of deoxygenation is still questioned. In photolithographic applications, this means that one cannot predict whether the minimum feature size is close to the diffraction limit or larger. In this work we have studied GO photoreduction with vacuum ultraviolet Synchrotron radiation. GO has been exposed to extreme-UV and soft-X-ray radiation and the ratio between C–O and sp2 C–C bonds has been measured by photoemission spectroscopy as a function of dose and number of photons. The deoxygenation rate has been demonstrated to be proportional to the imaginary part f2 of the oxygen scattering factor. Experiments at the wavelengths where the f2 of oxygen is close to its maximum (namely close to 2nm and between 20nm and 60nm) have demonstrated that GO can be rapidly reduced (even few minutes exposure time) with doses well below those needed for photothermal heating (the corresponding temperature rise is ∼1μK) and without damaging the basal plane (the in-plane sp2 C–C bonds are not broken). Efficient nanometer scale GO photopatterning is therefore demonstrated to be possible.

Microvascular oxygen consumption during sickle cell pain crisis

AbstractSickle cell disease is an inherited blood disorder characterized by chronic hemolytic anemia and episodic vaso-occlusive pain crises. Vaso-occlusion occurs when deoxygenated hemoglobin S polymerizes and erythrocytes sickle and adhere in the microvasculature, a process dependent on the concentration of hemoglobin S and the rate of deoxygenation, among other factors. We measured oxygen consumption in the thenar eminence during brachial artery occlusion in sickle cell patients and healthy individuals. Microvascular oxygen consumption was greater in sickle cell patients than in healthy individuals (median [interquartile range]; sickle cell: 0.91 [0.75-1.07] vs healthy: 0.75 [0.62-0.94] −ΔHbO2/min, P < .05) and was elevated further during acute pain crisis (crisis: 1.10 [0.78-1.30] vs recovered: 0.88 [0.76-1.03] −ΔHbO2/min, P < .05). Increased microvascular oxygen consumption during pain crisis could affect the local oxygen saturation of hemoglobin when oxygen delivery is limiting. Identifying the mechanisms of elevated oxygen consumption during pain crisis might lead to the development of new therapeutic interventions. This trial was registered at www.clinicaltrials.gov as #NCT01568710.

Hydrodeoxygenation of liquefied biomass on urchin-like MoS2

The synthesis of urchin-like crystalline MoS2 with micron unit size and surface area of 25m2g−1 and its application for the catalytic hydrogenation and hydrodeoxygenation (HDO) of liquefied wood sample are reported. We observed significant increase of deoxygenation rate considering intensities of CO and OH band intensities in liquid phase IR spectra. Prepared catalyst exhibited higher activity compared to commercial MoS2 powder. Elemental analysis of organic phase after HDO revealed equal elemental compositions for both samples, with higher yield in case of urchin-like MoS2. Oxygen content decreased from 43.3% to 8.2% (wt.); residual phenolic oxygen is not removable with catalyst described. Observed catalytic performance may provide new solutions in terms of biofuel processing.

Spatially Variable Deoxygenation in the Danshui River: Improvement in Model Calibration

A modeling study of the Danshui River, Taiwan, reveals that in-stream BOD deoxygenation rates vary significantly along the river as a result of the highly variable strength of wastewater discharges, which directly reflect the effluent characteristics. A comprehensive field data gathering and lab analysis effort for the study site is presented. Results of the data analyses yielded spatially variable CBOD deoxygenation and nitrification rates, which were incorporated in a model of the river. The model results indicate significant improvement of model calibration, thus enhancing the predictive capability of the model for its use in water quality management. To maximize the benefits of pollution control for the Danshui River system and to achieve the water quality management goal, concurrent reductions of CBOD and ammonia loads, instead of phased reduction of CBOD followed by ammonia reduction, are strongly recommended by the model results.

Deoxygenation of decanoic acid and its main intermediates over unpromoted and promoted sulfided catalysts

The transformation of decanoic acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340°C under 4MPa of total pressure (H2 pressure equal to 2.72MPa) in a fixed-bed reactor. The deoxygenation of decanoic acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of decanoic acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of decanoic acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase.

Central and peripheral adjustments during high-intensity exercise following cold water immersion

We investigated the acute effects of cold water immersion (CWI) or passive recovery (PAS) on physiological responses during high-intensity interval training (HIIT). In a crossover design, 14 cyclists completed 2 HIIT sessions (HIIT1 and HIIT2) separated by 30 min. Between HIIT sessions, they stood in cold water (10 °C) up to their umbilicus, or at room temperature (27 °C) for 5 min. The natural logarithm of square-root of mean squared differences of successive R-R intervals (ln rMSSD) was assessed pre- and post-HIIT1 and HIIT2. Stroke volume (SV), cardiac output (Q), O2 uptake (VO2), total muscle hemoglobin (t Hb) and oxygenation of the vastus lateralis were recorded (using near infrared spectroscopy); heart rate, Q, and VO2 on-kinetics (i.e., mean response time, MRT), muscle de-oxygenation rate, and anaerobic contribution to exercise were calculated for HIIT1 and HIIT2. ln rMSSD was likely higher [between-trial difference (90% confidence interval) [+13.2% (3.3; 24.0)] after CWI compared with PAS. CWI also likely increased SV [+5.9% (-0.1; 12.1)], possibly increased Q [+4.4% (-1.0; 10.3)], possibly slowed Q MRT [+18.3% (-4.1; 46.0)], very likely slowed VO2 MRT [+16.5% (5.8; 28.4)], and likely increased the anaerobic contribution to exercise [+9.7% (-1.7; 22.5)]. CWI between HIIT slowed VO2 on-kinetics, leading to increased anaerobic contribution during HIIT2. This detrimental effect of CWI was likely related to peripheral adjustments, because the slowing of VO2 on-kinetics was twofold greater than that of central delivery of O2 (i.e., Q). CWI has detrimental effects on high-intensity aerobic exercise performance that persist for ≥ 45 min.

Hydrothermal upgrading of algae paste: Application of 31P‐NMR

Although already proposed in the 1940s, hydrothermal upgrading of biomass, and specifically algae, to produce biocrude has only recently become a much researched topic. Algae are of special interest as they are capable of much higher biomass accumulation rates than terrestrial plants. To understand the transformation of algal biomass into biocrude, this process needs to be scrutinized in as much detail as possible to identify the most appropriate reaction conditions. It is usually not possible to identify individual transformation steps; however, in this article we demonstrate the use of 31P‐NMR to follow the fate of derivatized (2‐chloro‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaphospholane) hydroxyl groups to start understand, which chemical species are involved in the initial degradation steps.Our data show the occurrence of a very fast degradation of acidic OH groups (derived from the hydrolysis of lipids) and aliphatic OH groups (derived from the fast hydrolysis of carbohydrates). The degradation of proteins leads to polyphenols, which appear to be rather stable even over prolonged treatment periods. Small quantities of aromatic compounds are also formed as secondary degradation products through sugar dehydration and cyclization as well as peptide transformation. It appears that additional deoxygenation routes exist as the deoxygenation rate using 31P‐NMR and that determined by elemental analysis differ. The formed oil (biocrude) is compared with typical North Sea oils using simulated distillation and was found to contain a significant high boiling faction, which would require further treatment (e.g., hydrocracking) to shift the boiling range to a more valuable oil composition. © 2013 American Institute of Chemical Engineers Environ Prog, 32: 1002–1012, 2013

Correction: Non-Thermal Radio Frequency and Static Magnetic Fields Increase Rate of Hemoglobin Deoxygenation in a Cell-Free Preparation

Correction: Non-Thermal Radio Frequency and Static Magnetic Fields Increase Rate of Hemoglobin Deoxygenation in a Cell-Free Preparation