High Oxygen Demand Research Articles

Assessing artificial oxygenation in a riverine salt-wedge estuary with a three-dimensional finite-volume model

The presence of anoxia and hypoxia is increasingly observed in the bottom waters of many estuaries and coastal embayments, and remains a management challenge due to detrimental effects on estuarine biodiversity and overall amenity. As part of a multi-pronged strategy to tackle the problem of eutrophication in the Swan-Canning estuary, oxygenation plants have been installed in the upper reaches of the estuary to counteract the high oxygen demand and prevent hypoxia. In this study, we developed a three-dimensional hydrodynamic-biogeochemical model to simulate oxygen dynamics and assess the cost-benefit of different oxygenation operation regimes (e.g., night operation, all day operation or tidally-optimised operation). The model accurately captured the salt-wedge dynamics and the extent and severity of hypoxia under low and high flow conditions. The artificial oxygenation is shown to significantly improve oxygen conditions in the targeted zone under low flow conditions. The scenario assessment revealed a two-term power relationship between total oxygen supply and areal benefit, with scenarios highlighting that adding more oxygen would improve the oxygen conditions to a greater extent up to a limit (i.e., the law of diminishing returns). The total areal benefit achieved was found to be dependent on the total oxygen load rather than the timing of the oxygen input regime. The results also suggest that when designing an artificial oxygenation plant for an estuarine environment, the locations of oxygen addition should be carefully selected within the context of the local hydrology to achieve optimum results in target areas.

The Effect of Selective Breeding for High Voluntary Wheel‐Running Behavior on Femoral Nutrient Canal Abundance and Size

Mammalian skeletal tissue is aerobic, and has relatively high oxygen demand, presumably a result of the processes of bone modelling and remodeling. These processes are often associated with microfractures accrued from load bearing during locomotion, but they are also pivotal during bone growth and in the deposition/requisition of calcium from bone. Long bones receive blood from three sources, with the nutrient artery supplying the bulk of total blood volume in mammals (50–70%). Historically, measurement of blood flow into bones has been hindered by the compact bone surrounding the vessels. However, the size of the nutrient artery can be estimated from the dimensions of the nutrient canal, which is present long after the vascular tissue has degenerated, and so can be quantified in skeletal materials, including fossils. The literature on nutrient arteries/canals is sparse, with most studies consisting of anatomical descriptions from surgical proceedings, and only a few investigating the links between nutrient canals and physiology or behavior. Moreover, no study to date has accurately reconstructed the size and shape of the nutrient canal. The primary objective of this study was to model the nutrient canal of the femur in mice with known physiological and behavioral differences. For this study, mice from an artificial selection experiment for high voluntary wheel‐running behavior were used. Mice from the four replicate High Runner (HR) lines of the experiment are known to differ from four non‐selected Control (C) lines in both locomotor and metabolic activity, with HR mice having increased voluntary wheel‐running behavior and maximal aerobic capacity (VO2max) during forced treadmill exercise. 137 femora from adult mice (average age of approximately 7.5 months) of the 11th generation of this selection experiment were μCT scanned. Three‐dimensional virtual reconstructions of nutrient canals were measured for minimum cross‐sectional area (as an index of blood flow). Nutrient canals varied far more in number and shape than prior descriptions would indicate, regardless of genetic background (i.e., HR vs. C lines) or sex. Canals adopted non‐linear shape and pathing as they traversed from the periosteum to the medullary cavity, occasionally even branching within the cortical bone. Additionally, mice from both HR and C lines averaged more than four nutrient canals per femur, a stark contrast to the 1–2 nutrient canals described for femora from rats, pigs, and humans in prior literature. Mice from HR lines had significantly larger nutrient canal area than C lines, which was not the result of an increase in the number of nutrient canals, but rather an increase in their average size. This study demonstrates that mice with an evolutionary history of increased locomotor activity and maximal aerobic metabolic rate have a concomitant increase in the size of their nutrient canals. While the primary determinant of nutrient canal size is currently unknown, the present results bolster the use of nutrient canal size as a paleoindicator of aerobically supported levels of physical activity.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A review on bioremediation of pulp and paper mill effluent – An alternative to conventional remedial technologies

At present, a large amount of water required for paper production and various chemicals has been identified in effluents, which is produced at different steps of paper making in paper mills. The pulp and paper industry is typically related to pollution difficulties related to high biological oxygen demand (BOD), chemical oxygen demand (COD), colour, suspended solids, lignin and chlorinated compounds. Several studies have been made on eliminate these difficulties of pulp and paper effluents, the problem still continues. Although the physical and chemical methods are on the track of treatment, they are not on par with biological treatment because of cost ineffectiveness and residual effects. The biological treatment is known to be effective in reducing the organic load and toxic effects of paper mill effluents. Some microorganisms including bacteria and fungi have been involved in degrading the chemicals present in pulp and paper mill effluent. This article is an overview of the attempts made by several researchers worldwide to use biotechnological methods for degradation of the toxic compounds present in pulp and paper mill effluents by using fungi, bacteria, algae and enzymes. The current study clearly shows that application of native dominant bacterial and fungal isolates may be used forthe treatment of large pulp and paper mills effluents.

Production of Selenium-Enriched Yeast (Kluyveromyces marxianus) Biomass in a whey-based Culture Medium

Fil: Gurdo, Nicolas. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Investigaciones Biotecnologicas. Instituto de Investigaciones Biotecnologicas Dr. Raul Alfonsin (sede Chascomus). Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnologicas. Instituto de Investigaciones Biotecnologicas Dr. Raul Alfonsin (sede Chascomus); Argentina

Diagenesis of Organic Matter in the Top Layer of the Sediments of the Peter the Great Bay in Hypoxia Locations

During Cruise 62nd of the R/V “Professor Gagarinsky” in September, 2014, the carbonate system of sediments and contents of nutrients and organic carbon in pore water were studied in two geochemical stations located in hypoxia areas in the Peter the Great Bay. It was established that the concentrations of silica, phosphorus, and ammonium increase by 5, 10, and 20 times, respectively, with sediment depth to 70–80 cm. The alkalinity, dissolved inorganic carbon, and the partial pressure of carbon dioxide significantly increase with depth, while рН value and organic matter (ОM) decrease. Changes in the chemical composition of pore water with sediment depth (0–80 cm) are caused by anaerobic microbial degradation of OM, concentration of which in the top sediment layer is 2–3%. The degradation products of OM in the bottom waters of bay and pore waters of bottom sediments indicate that its main sources are diatoms. During hypoxia, the oxygen demand rate by sediment surface near Furugelm Island is estimated to be 5 mmol/(m2 day). A combination of such factors as downwelling circulation, the absence of photosynthetically active radiation, and the high oxygen demand rate at the water/sediment interface provides hypoxia formation in the depressions of the Peter the Great Bay bottom topography.

Hypoxia Pathway Proteins As Central Mediators of Metabolism in the Tumor Cells and Their Microenvironment.

Low oxygen tension or hypoxia is a determining factor in the course of many different processes in animals, including when tissue expansion and cellular metabolism result in high oxygen demands that exceed its supply. This is mainly happening when cells actively proliferate and the proliferating mass becomes distant from the blood vessels, such as in growing tumors. Metabolic alterations in response to hypoxia can be triggered in a direct manner, such as the switch from oxidative phosphorylation to glycolysis or inhibition of fatty acid desaturation. However, as the modulated action of hypoxia-inducible factors or the oxygen sensors (prolyl hydroxylase domain-containing enzymes) can also lead to changes in enzyme expression, these metabolic changes can also be indirect. With this review, we want to summarize our current knowledge of the hypoxia-induced changes in metabolism during cancer development, how they are affected in the tumor cells and in the cells of the microenvironment, most prominently in immune cells.

Coagulation-flocculation treatment of white pepper (<i>Piper nigrum L.</i>) processing wastewater

Wastewater generated in white pepper (Piper nigrum L.) processing contains high Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and hydrolyzable tannins that results dark tan/brown colour effluent which cannot be discharged to the environment without proper treatment. Therefore, these experiments were conducted to investigate the effectiveness of electro-coagulation using aluminum (Al) electrodes and coagulation-flocculation with Alum [Al2(SO4)3.18H2O] in reducing the strength of pepper soaked effluent. A laboratory scale electro-coagulation unit was made using two aluminium plates (9 cm × 5 cm × 0.3 cm) as electrodes leaving a 0.5 cm gap between plates and powered with a 12 V DC power supply through a resistance box which is used to regulate the current density. The current density could be controlled between 0-1 A. Coagulation flocculation with Alum was tested at five doses; 1 to 5 g/L with 1 g increments at laboratory scale. The effluent colour was measured using a spectrophotometer at a wave length of 600 nm. According to the results, removal efficiencies of colour, Turbidity and COD were 94%, 91% and 89%, respectively for 20 minutes of electro-coagulation and 92%, 90% and 92%, respectively with 3 g/L Alum treatment. The pH of the effluent during electro-coagulation for 20 minutes increased to 9.0 while Alum treatment with 3g/L reduced to 5. When treated effluent filtered through a fine sand filter, Total Dissolved Solids (TDS), Electrical Conductivity (EC) and COD could be reduced further and reached the standard values to discharge in to the environment as irrigation water.

Whey utilization in a two-stage fermentation process

Abstract Whey is a major by-product of the cheese and dairy industry and has valuable nutritional constituents, however poses a major environmental risk if disposed of without prior treatment. The main components of whey except of water are lactose, lactic acid, soluble proteins, lipids, vitamins and mineral salts which give a very high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) load (30,000 - 50,000 ppm and 60.000 - 80,000 ppm, respectively) to the whey. This composition provides adequate nitrogen and carbon source to be utilized by microorganisms. The aim of this study was to examine the whey utilization in a two-stage fermentation process using Lactobacillus species and Propionibacterium acidipropionici. In the first stage Lactobacillus species utilise the main part of the nitrogen source while covert lactose content to lactic acid. In the second stage Propionibacterium acidipropionici utilize lactic acid and produce propionic acid. This two-stage fermentation process can be a feasible option, both for bioremediation of whey and production of propionic acid from waste sources. High lactose conversion (>90%) to lactic acid was achieved at the first stage, but its conversion to propionic acid during the second stage was insufficient (~30%). The COD was successfully decreased during the fermentations.

Pyruvate enhancement of cardiac performance: Cellular mechanisms and clinical application.

Cardiac contractile function is adenosine-5'-triphosphate (ATP)-intensive, and the myocardium's high demand for oxygen and energy substrates leaves it acutely vulnerable to interruptions in its blood supply. The myriad cardioprotective properties of the natural intermediary metabolite pyruvate make it a potentially powerful intervention against the complex injury cascade ignited by myocardial ischemia-reperfusion. A readily oxidized metabolic substrate, pyruvate augments myocardial free energy of ATP hydrolysis to a greater extent than the physiological fuels glucose, lactate and fatty acids, particularly when it is provided at supra-physiological plasma concentrations. Pyruvate also exerts antioxidant effects by detoxifying reactive oxygen and nitrogen intermediates, and by increasing nicotinamide adenine dinucleotide phosphate reduced form (NADPH) production to maintain glutathione redox state. These enhancements of free energy and antioxidant defenses combine to augment sarcoplasmic reticular Ca2+ release and re-uptake central to cardiac mechanical performance and to restore β-adrenergic signaling of ischemically stunned myocardium. By minimizing Ca2+ mismanagement and oxidative stress, pyruvate suppresses inflammation in post-ischemic myocardium. Thus, pyruvate administration stabilized cardiac performance, augmented free energy of ATP hydrolysis and glutathione redox systems, and/or quelled inflammation in a porcine model of cardiopulmonary bypass, a canine model of cardiac arrest-resuscitation, and a caprine model of hypovolemia and hindlimb ischemia-reperfusion. Pyruvate's myriad benefits in preclinical models provide the mechanistic framework for its clinical application as metabolic support for myocardium at risk. Phase one trials have demonstrated pyruvate's safety and efficacy for intravenous resuscitation for septic shock, intracoronary infusion for heart failure and as a component of cardioplegia for cardiopulmonary bypass. The favorable outcomes of these trials, which argue for expanded, phase three investigations of pyruvate therapy, mirror findings in isolated, perfused hearts, underscoring the pivotal role of preclinical research in identifying clinical interventions for cardiovascular diseases. Impact statement This article reviews pyruvate's cardioprotective properties as an energy-yielding metabolic fuel, antioxidant and anti-inflammatory agent in mammalian myocardium. Preclinical research has shown these properties make pyruvate a powerful intervention to curb the complex injury cascade ignited by ischemia and reperfusion. In ischemically stunned isolated hearts and in large mammal models of cardiopulmonary bypass, cardiac arrest-resuscitation and hypovolemia, intracoronary pyruvate supports recovery of myocardial contractile function, intracellular Ca2+ homeostasis and free energy of ATP hydrolysis, and its antioxidant actions restore β-adrenergic signaling and suppress inflammation. The first clinical trials of pyruvate for cardiopulmonary bypass, fluid resuscitation and intracoronary intervention for congestive heart failure have been reported. Receiver operating characteristic analyses show remarkable concordance between pyruvate's beneficial functional and metabolic effects in isolated, perfused hearts and in patients recovering from cardiopulmonary bypass in which they received pyruvate- vs. L-lactate-fortified cardioplegia. This research exemplifies the translation of mechanism-oriented preclinical studies to clinical application and outcomes.

BIOGEOCHEMICAL ANALYSIS IN RELATION TO WATER QUALITY OF WAWA DAM, RIZAL, PHILIPPINES

This paper investigates the biogeochemical components of Wawa Dam, to determine its viability for human consumption. Macro-invertebrates and geological structures were assessed in relation to water quality. Quantitative analysis on the physicochemical parameters, such as, pH, temperature, total dissolved solids, total suspended solids, biochemical oxygen demand, dissolved oxygen, nitrates and orthophosphates were done, to compare with the standard criteria set by the Department of Environmental and Natural Resources Administrative Order 90-34, in four consecutive months, covering rainy and dry seasons. Results showed that, Class Insecta with 30.91% were the most abundant macro-invertebrates, while, sedimentary rocks, dominated the geological structures with 69.10%. Total suspended solids and total dissolved solids, revealed significant concentrations (P<0.05) having low levels with average mean values of 33.25 mg L and 155 mg L, respectively, as compared with the standard criteria for Class A (drinking water with complete treatment). Biological oxygen demand, dissolved oxygen, nitrates and orthophosphates with average mean values of 9.5 mg L, 6.4 mg L, 11 mg L and 1.1 mg L, respectively, did not meet the standard criteria. Temperature and pH were within the range of standard level. Wawa Dam with the presence of inhabitants and other sources of pollution, the water quality is deteriorating, based on these observed parameters: nutrient concentrations were quite alarming; macro-invertebrates were threatened, due to a very high biological oxygen demand, and almost in the minimum level of dissolved oxygen. Total suspended solids and total dissolved solids were significant, because of their low concentrations.

SPENT SULPHITE LIQUOR FOR CULTIVATION OF AN EDIBLE RHIZOPUS SP.

Spent sulphite liquor, the major byproduct from the sulphite pulp production process, was diluted to 50% and used for production of an edible zygomycete Rhizopus sp. The focus was on production, yield, and composition of the fungal biomass composition. The fungus grew well at 20 to 40°C, but 32°C was found to be preferable compared to 20 and 40°C in terms of biomass production and yield (maximum of 0.16 g/g sugars), protein content (0.50-0.60 g/g), alkali-insoluble material (AIM) (ca 0.15 g/g), and glucosamine content (up to 0.30 g/g of AIM). During cultivation in a pilot airlift bioreactor, the yield increased as aeration was raised from 0.15 to 1.0 vvm, indicating a high demand for oxygen. After cultivation at 1.0 vvm for 84 h, high yield and production of biomass (up to 0.34 g/g sugars), protein (0.30-0.50 g/g), lipids (0.02-0.07 g/g), AIM (0.16-0.28 g/g), and glucosamine (0.22-0.32 g/g AIM) were obtained. The fungal biomass produced from spent sulphite liquor is presently being tested as a replacement for fishmeal in feed for fish aquaculture and seems to be a potential source of nutrients and for production of glucosamine.

From the Cover: In Vitro and In Vivo Blood-Brain Barrier Penetration Studies with the Novel Cyanide Antidote Candidate Dimethyl Trisulfide in Mice.

Recent in vitro and in vivo studies highlight the strong potential of dimethyl trisulfide (DMTS) as an antidote for cyanide (CN) intoxication. Due to its high oxygen demand, the brain is one of the main target organs of CN. The blood-brain barrier (BBB) regulates the uptake of molecules into the brain. In the literature, there is no data about the ability of DMTS to penetrate the BBB. Therefore, our aim was to test the in vitro BBB penetration of DMTS and its in vivo pharmacokinetics in blood and brain. The in vitro BBB penetration of DMTS was measured by using a parallel artificial membrane permeability assay (BBB-PAMPA), and a triple BBB co-culture model. The pharmacokinetics was investigated in a mouse model by following the DMTS concentration in blood and brain at regular time intervals following intramuscular administration. DMTS showed high penetrability in both in vitro systems (apparent permeability coefficients: BBB-PAMPA 11.8 × 10-6 cm/s; cell culture 158 × 10-6 cm/s) without causing cell toxicity and leaving the cellular barrier intact. DMTS immediately absorbed into the blood after the intramuscular injection (5 min), and rapidly penetrated the brain of mice (10 min). In addition to the observed passive diffusion in the in vitro studies, the contribution of facilitated and/or active transport to the measured high permeability of DMTS in the pharmacokinetic studies can be hypothesized. Earlier investigations demonstrating the antidotal efficacy of DMTS against CN together with the present results highlight the promise of DMTS as a brain-protective CN antidote.

Effective bioremoval of syntan using fungal laccase to reduce pollution from effluent

Syntans are synthetically prepared tanning agents from phenols that play an important role in leather making by enhancing the filling, grain characteristics and dyeing property. A considerable amount of syntan emanated in waste water contributes high pollution load with other heterocyclic aromatic compounds and causes serious environmental impact resulting in high oxygen demand. In order to overcome this, suitable biodegradation techniques have been developed using laccase from Penicillium chrysogenum. The influence of different environmental parameters on the biodegradation has also been studied which reveals that the maximum syntan degradation was obtained at pH 5.0, temperature at 32 °C for the duration of 48 h. Maximum biodegradation was found to be 96 and 94% for samples containing phenolic and melamine syntan. Ultraviolet spectra showed the peaks at around 280 nm for the presence of phenolic (DI) syntan and at 220 nm for melamine syntan which were disappeared later in the experimental sample indicating complete degradation of syntans. Fourier spectral analysis indicated that the peaks at the region between 1443–1574 and 1176 cm−1 correspond to C=C stretching and C–H bending for aromatic region which were later disappeared in the experimental sample. Ultrapressure liquid chromatography elution profiles of syntans showed relatively shorter retention time indicating formation of oxidized products. Syntans, namely DI and FB6, showed reduction in chemical oxygen demand up to 87.71 ± 4 and 83.38 ± 5%, respectively, while total organic carbon reduction was achieved up to 82.37 and 80.72%, respectively. Toxicity studies revealed that seeds were well germinated using the treated (biodegradation) samples by crude laccase .

Physiological and ecological implications of ocean deoxygenation for vision in marine organisms.

Climate change has induced ocean deoxygenation and exacerbated eutrophication-driven hypoxia in recent decades, affecting the physiology, behaviour and ecology of marine organisms. The high oxygen demand of visual tissues and the known inhibitory effects of hypoxia on human vision raise the questions if and how ocean deoxygenation alters vision in marine organisms. This is particularly important given the rapid loss of oxygen and strong vertical gradients in oxygen concentration in many areas of the ocean. This review evaluates the potential effects of low oxygen (hypoxia) on visual function in marine animals and their implications for marine biota under current and future ocean deoxygenation based on evidence from terrestrial and a few marine organisms. Evolutionary history shows radiation of eye designs during a period of increasing ocean oxygenation. Physiological effects of hypoxia on photoreceptor function and light sensitivity, in combination with morphological changes that may occur throughout ontogeny, have the potential to alter visual behaviour and, subsequently, the ecology of marine organisms, particularly for fish, cephalopods and arthropods with 'fast' vision. Visual responses to hypoxia, including greater light requirements, offer an alternative hypothesis for observed habitat compression and shoaling vertical distributions in visual marine species subject to ocean deoxygenation, which merits further investigation.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

Redox Properties of Tryptophan Metabolism and the Concept of Tryptophan Use in Pregnancy.

During pregnancy, tryptophan (Trp) is required for several purposes, and Trp metabolism varies over time in the mother and fetus. Increased oxidative stress (OS) with high metabolic, energy and oxygen demands during normal pregnancy or in pregnancy-associated disorders has been reported. Taking the antioxidant properties of Trp and its metabolites into consideration, we made four hypotheses. First, the use of Trp and its metabolites is optional based on their antioxidant properties during pregnancy. Second, dynamic Trp metabolism is an accommodation mechanism in response to OS. Third, regulation of Trp metabolism could be used to control/attenuate OS according to variations in Trp metabolism during pregnancy. Fourth, OS-mediated injury could be alleviated by regulation of Trp metabolism in pregnancy-associated disorders. Future studies in normal/abnormal pregnancies and in associated disorders should include measurements of free Trp, total Trp, Trp metabolites, and activities of Trp-degrading enzymes in plasma. Abnormal pregnancies and some associated disorders may be associated with disordered Trp metabolism related to OS. Mounting evidence suggests that the investigation of the use of Trp and its metabolites in pregnancy will be meanful.

The Potency of Indonesia Native Plants as Natural Coagulant: a Mini Review

Indonesia is a tropical country which is known for its high variety of natural resources. However, there is limited access to clean water, thus forcing people in rural areas to use turbid water. Furthermore, some of water sources in Indonesia are already polluted by heavy metals with high biological oxygen demand (BOD) and chemical oxygen demand (COD) value. Simple and easy water purification methods are needed to overcome this situation. Coagulation and flocculation are widely used method to treat water. However, chemical coagulants (alum, ferrum, PAC, etc.) are not easily obtained and could cause some health problems if treated water is consumed. Natural coagulants have a good potential to solve these problems. Various possible plant-based natural coagulants which are abundant in Indonesia are highlighted in this paper. Fruit wastes and inedible legumes are suggested to be used as natural coagulant as there are no food competition presents. Further research is needed especially to scale up laboratory scale research that has been done in these years; thus, it can be applied to solve clean water scarcity problem.

Abstract 2148: Phenyl butyrate inhibits pyruvate dehydrogenase kinase 1 and contributes to its anti-cancer effects

Abstract In cancer cells, the metabolic features are significantly different from those of normal ones, which are hallmarks of several malignancies. Recent studies brought atypical cellular metabolism, such as aerobic glycolysis or the Warburg effect, into the scientific limelight. Pyruvate dehydrogenase kinase 1 (PDK1), a key enzyme in the pathway of glucose metabolism, could inactivate the pyruvate dehydrogenase (PDH) by phosphorylating it and preserving the substrates pyruvate, lactate and alanine for gluconeogenesis. Overexpression of PDK1 could block the oxidative decarboxylation of pyruvate to satisfy high oxygen demand in cancer cells, while inhibition of PDK1 could upregulate the activity of PDH and rectify the balance between the demand and supply of oxygen, which could lead to cancer cell death. Thus, inhibitors targeting PDK1 might be a promising strategy for cancer treatment by acting on glycolytic tumors while showing minimal side effects on the oxidative healthy organs. Phenyl butyrate (PB) has been proved to decrease PDH phosphorylation level and increase PDH activity by inhibiting PDK1 in fibroblast cells, PDH deficiency zebrafish and wild type mice. PB has also shown efficacy in many cancers and so far, all of its anti-tumor activity has been attributed to the histone deacetylase (HDAC) inhibitor mode of action. As PDK1/PDH controls the critical switch between oxidative phosphorylation and glycolysis in cancer cells, PDK1 is a key target in tumor metabolism for anti-cancer treatment. We hypothesize that the therapeutic effects of PB in cancers might depend on suppressing PDKs and promoting PDH activity, in addition to its proposed role as HDAC inhibitor. We showed that PB directly inhibited the kinase activity of PDK1 in a purified system. In several different cancer cell lines, PB reduced the phosphorylation level of PDH, increased the mitochondrial respiration, decreased glycolysis in cytoplasm, reversed mitochondrial hyperpolarization, activated some proteins in apoptotic signalling pathway and then induced the apoptosis of cells. In summary, this is the first study indicated that PB could exert its anti-cancer effects through inhibiting PDK1, altering the mitochondrial bioenergetics and inducing apoptosis. Note: This abstract was not presented at the meeting. Citation Format: Wen Zhang, Kin Yip Tam. Phenyl butyrate inhibits pyruvate dehydrogenase kinase 1 and contributes to its anti-cancer effects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2148. doi:10.1158/1538-7445.AM2017-2148

Challenges with elemental sulfur removal during the leaching of copper and zinc sulfides, and from the residues; a review

The hydrometallurgical recovery of metal values from sulfide concentrates, such as chalcopyrite, enargite, and sphalerite, typically generates elemental sulfur in the oxidative leaching processes. The main disadvantage of the generation of sulfur is that it retards or hampers the efficiency of the leaching process. The oxidative leaching of sulfide mineral concentrates at temperatures above 180°C and at high pressures, known as total pressure oxidation (TPOX), completely converts the sulfide minerals to sulfate ions and sulfuric acid. However, the TPOX process has several negative aspects that increase costs, including the capital cost of the TPOX operations, the high oxygen demand to convert sulfide to sulfate, and the lime that is required to neutralize the excess acid in the autoclave discharge. Alternative processes that can reduce the capital and operating costs associated with the treatment of sulfidic concentrates include the medium temperature pressure oxidation (MT-POX) processes that operate at or below 150°C, such as the Cominco Engineering Services Ltd. (CESL) process, and atmospheric leaching (ATL) processes, such as the Albion and Galvanox™ processes. In the MT-POX and ATL processes, a proportion of the sulfides from the sulfide concentrates are oxidized to elemental sulfur, reducing the generation of acid and the oxygen demand of the oxidative leaching processes. Despite the lower operating and capital costs of the MT-POX and ATL processes, elemental sulfur may cause environmental problems such as acid mine drainage, or downstream process operation problems such as low solid/liquid separation efficiency or leaching efficiency. Thus, it is important to remove the elemental sulfur effectively during the leach process or from the residues after the leach process. In this paper, we present a summary of the research that has been conducted to decrease the passivating effect of molten or solid sulfur during the leaching of copper sulfide and zinc sulfide, and the approaches to remove the elemental sulfur from the leach residues. Also, the paper reviews the most important approaches that have been developed to address the elemental sulfur issue, including the application of polytetrafluoroethylene (C2F4)n, carbon tetrachloride (CCl4), ozone, nanosilica, sulfur-oxidizing bacteria, thermophilic iron-oxidizing archaea, sulfur-reducing bacteria (SRB), calcium lignosulfonate, quebracho, tetrachloroethylene (C2Cl4), Na2S leaching–CO2 precipitating, and vacuum and atmospheric distillation.

RETINOPATHY OF PREMATURITY PRACTICES: A NATIONAL SURVEY OF CANADIAN NEONATAL INTENSIVE CARE UNITS

BACKGROUND: Retinopathy of prematurity (ROP) accounts for significant morbidity in preterm infants. Early detection and treatment helps prevent adverse sequelae. The objective of this study was to survey the current screening inclusion criteria, treatment options, supportive care and post screening events for ROP in tertiary level Neonatal Intensive Care Units (NICU’s) in Canada. OBJECTIVES: The objective of this study was to survey the current screening inclusion criteria, treatment options, supportive care and post screening events for ROP in tertiary level Neonatal Intensive Care Units (NICUs) in Canada. DESIGN/METHODS: The study was designed as a prospective observational study where a survey was sent out to all 29 level three NICU’s across Canada. Following ethics exemption from the local research ethics board, a cross sectional survey was distributed across all level three NICU’s in Canada from September 1 to December 30, 2015. The tool was designed to elicit information on the screening practices for detection of ROP in tertiary NICU’s. In addition, information on the ROP screening processes, including the timing of screening and grounds for screening infants outside the criteria were collected. The survey also explored the screening process from an organizational standpoint in terms of the person responsible for initiating the screening processes, choice of mydriatics as well as organizing follow up. The practice and use of supportive measures during ROP screening and treatment options provided were also captured.The primary outcome was defined as adherence to the current CPS/COS or AAP guidelines. Specifically, guideline adherence was assessed for the following criteria: inclusion of an infant for ROP screening, age at which first ROP exam was initiated, circumstances where infants outside the screening criteria were deemed eligible for inclusion in the screening process and appropriate follow up processes. Secondary outcomes were defined as the supportive practices in use during the ROP screening examination. This includes the type and dose of mydriatics used, and measures to reduce photophobia and discomfort after ROP related therapeutic interventions. We also assessed healthcare system perspectives related to ROP screening and treatment. This was determined by the availability of dedicated personnel to coordinate the exam, pre-printed order sheets for medication and equipment required, measures to ensure appropriate follow up, use of RetCam (Clarity Medical Systems INC.), ROP treatment options (Anti vascular endothelial growth factor [anti-VEGF] and/or Laser) and treatment location. RESULTS: Twenty two level three nurseries responded to the survey (76 % response rate). Ten different ROP screening inclusion criteria were found to be in use with significant variation in gestational age and birth weight criteria. Reasons for screening babies outside any given unit’s inclusion criteria included unstable clinical course or high oxygen demand as decided by the attending neonatologist. Many other national variations also exist regarding the supportive, procedural and treatment protocols surrounding ROP screening such as Ret Cam use, use of mydriatics and preprinted order sheets. From a treatment standpoint, 50 percent of the centers preferred laser while the remaing 50 percent prefereed Anti VEGF(Vascular Endothelial Growth factor) CONCLUSION: Despite national guidelines, there exists significant variation in ROP screening inclusion criteria practices among neonatal units in Canada. For the many other aspects of ROP screening and treatment, for which there are no national guidelines there also exists significant variations in practice patterns. There is therefore an urgent need for better evidence based screening guidelines as well as a need to standardize supportive measures surrounding ROP screening and treatment, followed by efforts to encourage national uptake of these recommendations.

Fed-Batch Fermentation for Spinosad Production in an Improved Reactor

As a kind of aerobic bacteria, Saccharopolyspora spinosa exhibits a high demand for oxygen. In the fermentation process, the methods of increasing ventilation and improving agitation speed are usually adopted to achieve higher values of dissolved oxygen. These methods decrease the efficiency of spinosad biosynthesis. In this study, an improved reactor was designed to solve these problems. The exhaust gas reflux device, impellers, and baffles were improved. Furthermore, we established the kinetic models for the cell growth, substrate consumption and spinosad generation in batch fermentation process. The simulation results were in good agreement with the experimental data. Spinosad production reached 583.86 mg/L after employing the suitable feeding strategy by fed-batch fermentation in the improved reactor, whereas it was only 157.01 mg/L before optimization. The method described can provide insight to strengthen spinosad production and can be extended to the culturing process of filamentous aerobic bacteria.