Response mechanism of denitrifying anaerobic methane oxidation microorganisms to ammonia

2020 ◽  
Vol 17 (1) ◽  
pp. 17 ◽  
Author(s):  
Juqing Lou ◽  
Jiaping Li ◽  
Xilei Wang
Keyword(s):  
Methane Oxidation ◽  
Nitrogen Removal ◽  
Experimental Studies ◽  
Ammonia Concentration ◽  
Anaerobic Methane Oxidation ◽  
Limiting Factor ◽  
Response Mechanism ◽  
Short Term ◽  
Damo Bacteria

Environmental contextDenitrifying anaerobic methane oxidation (DAMO) is a new process in wastewater treatment with the potential to provide cheap and sustainable development. To better apply this technology to the large scale, we studied the response mechanism of DAMO microorganisms to ammonia, the main form of nitrogen in the nitrogenous wastewater. The results can provide a theoretical basis for the stable and efficient operation of DAMO processes. AbstractThe dominant microorganisms in the denitrifying anaerobic methane oxidation (DAMO) process are primarily DAMO bacteria and DAMO archaea, which can simultaneously realise methane oxidation and denitrification. Ammonia is the primary form of nitrogen found in wastewater. This study focuses on a coexistence system that contains both DAMO bacteria and DAMO archaea (DAMO co-system). The short- and long-term effects of NH4+-N on the DAMO co-system were investigated at both the macro level (such as denitrification performance) and the micro level (such as microbial structure and community). Short-term experimental studies demonstrated that the safe concentration of ammonia for this system was 250mgNL−1. When the ammonia concentration was 500mgNL−1, the nitrogen removal efficiency was significantly inhibited. With an increase in concentration and an extension of time, the inhibitory effect of ammonia was enhanced. Long-term experimental studies showed that the nitrogen removal performance of DAMO was completely inhibited when the ammonia concentration reached 1000mgNL−1 and that ammonia had a toxic accumulation effect on the DAMO co-system. The results of the pH experimental study demonstrated that free ammonia (FA) was the limiting factor in the alkaline condition, while ionised NH4+ was the limiting factor in neutral and acidic conditions. Scanning electron microscopy (SEM) demonstrated that the microbes in the DAMO co-system shrank after short-term exposure and that the microorganisms shrank in the shape of polygons. High-throughput sequencing analysis demonstrated that the community structure of the DAMO co-system changed substantially, and the species diversity and abundance decreased distinctly after long-term inhibition. A genus analysis indicated that the reduction in Nitrospirae may be an internal reason for the decrease in the denitrification performance of the DAMO co-system.

Effects of short- and long-term treatments of sardine (Sardina pilchardus) protein hydrolysates on blood lipid concentrations and antioxidant status, in rats fed cholesterol-enriched diets

2022 ◽  
Vol 11 (6) ◽  
pp. 733-745
Author(s):  
Nora Athmani ◽  
Allaoui Amine ◽  
Nasri Moncef ◽  
Boualga Ahmed
Keyword(s):  
Experimental Studies ◽  
Blood Lipid ◽  
Protein Hydrolysates ◽  
High Cholesterol ◽  
Short Term ◽  
Hypercholesterolemic Diet ◽  
Short And Long Term ◽  
Antioxidant Enzymes Activities ◽  
Radical Attack

Hypercholesterolemia is a major risk factor of cardiovascular diseases (CVD). A limited number of experimental studies have shown that sardine protein hydrolysates (SPH) could be a very useful natural compound to prevent hy-percholesterolemia by both improving the lipoprotein profile and modula-ting oxidative stress. In the present study, the effect of short and long term treatments with SPH were examined on serum lipid contents, lipid peroxida-tion and antioxidant enzymes activities in rats fed cholesterol-enriched diet. At day 0, rats were divided into five groups. The group of day 0 was the stan-dard group, and the four remaining groups were divided into two parts of two groups each consuming for 14 or 28 days an hypercholesterolemic diet, and treated (HC-SPH) or not (HC) by gavage with SPH. Compared with day 0, serum TC contents were increased at day 14 and remained unchanged at day 28 in HC-SPH group. These values were decreased in HC-SPH versus HC. Liver and heart TBARS concentrations were increased at day 14 then diminished at day 28 in HC-SPH group. Liver and heart SOD and CAT activities were decrea-sed at short term then remained unchanged at long term in HC-SPH group. In addition, these activities were enhanced in HC-SPH versus HC. In conclusion, these results indicate the potential effects of short and long term treatments of SPH to improved cholesterolemia and reduced radical attack in rats fed high-cholesterol diets.

Nitrate/nitrite dependent anaerobic methane oxidation coupling with anammox in membrane biotrickling filter for nitrogen removal

2021 ◽  
Vol 193 ◽  
pp. 110533
Author(s):  
Sheng-Qiang Fan ◽  
Guo-Jun Xie ◽  
Yang Lu ◽  
Bing-Feng Liu ◽  
De-Feng Xing ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Nitrogen Removal ◽  
Anaerobic Methane Oxidation ◽  
Biotrickling Filter ◽  
Oxidation Coupling

Wooden Trusses With Nodal Joints On Glued Flat Rods

2020 ◽  
pp. 9-15
Keyword(s):  
Bearing Capacity ◽  
Test Procedure ◽  
Experimental Studies ◽  
Operational Reliability ◽  
Design Solution ◽  
Short Term ◽  
High Degree ◽  
Wooden Structures ◽  
Node Type

Wooden trusses are widely used in construction and differ in a variety of structural forms. In general, their bearing capacity and stiffness are determined by the design solution of the node joints. In order to accept significant loads and reduce the overall deformation of trusses, it is necessary to develop new types of nodes that would also be characterized by low labor intensity of manufacturing and a high degree of operational reliability. Proposed by the authors nodes of wooden trusses based on steel glued flat rods are met the above requirements. The article describes the results of experimental studies of a wooden truss with nodal joints on glued flat rods under the short-term loads. The layout principles of the proposed node type are given; test procedure of experimental structures and results of experimental studies are presented: features of operation of steel connecting plates glued into wood in the nodes are revealed. It is shown that the adopted design solution of nodes refers to the joints of wooden structures of a rigid type and provides sufficient load-bearing capacity of the trusses and their increased rigidity. The nature of the destruction and the value of the destructive load confirmed the operational reliability of the proposed type of wooden trusses, including under the action of long-term loads. The analysis of the results revealed the directions of further improvement of wooden trusses nodes with steel glued flat rods.

Toward a Medical Understanding of Marihuana

1969 ◽  
Vol 14 (6) ◽  
pp. 591-600 ◽  
Author(s):  
Conrad J. Schwarz
Keyword(s):  
English Language ◽  
Medical Literature ◽  
Experimental Studies ◽  
Personal Characteristics ◽  
Short Term ◽  
The Past ◽  
Wide Range ◽  
Indian Hemp ◽  
Made In

This paper is based on a review of the English language medical literature over the past 35 years on Indian Hemp, with direct reference being made to the more significant articles published during that time. The paucity of direct experimental observation is noted and the difficulties in experimental studies are highlighted by descriptions of the wide variations in the potency of Indian Hemp derivatives. Specific references are provided for the wide range of observations made in relation to acute and chronic physical and psychological effects, personal characteristics of the users and possible factors in causation. It is concluded that marihuana is a poorly defined intoxicant which varies in potency, deteriorates with time and whose chemical composition is largely unknown at present. There are wide variations in human response and the state of intoxication itself carries with it varying degrees of unpleasant physical and psychological experiences. The association between hashish and, to a lesser extent, marihuana and short-term and long-term complications is discussed in relation to complex variables, of which the drug is but one factor.

scholarly journals Aem Analyses of SRL 131 Glass Altered as a Function of SA/V

1991 ◽  
Vol 257 ◽  
Author(s):  
James J. Mazer ◽  
John K. Bates ◽  
Bruce M. Biwer ◽  
C. R. Bradley
Keyword(s):  
Experimental Studies ◽  
Volume Ratio ◽  
Scaling Factor ◽  
Experimental Results ◽  
Geologic Repository ◽  
Short Term ◽  
Natural Systems ◽  
Test Conditions ◽  
Solution Volume

Experimental studies of silicate glass/water reactions at low temperatures have previously identified the glass surface area-to-solution volume ratio (SA/V) as a significant rate determining parameter [1-4]. The value produced when SA/V is multiplied by reaction time, hereafter referred to as SVT, has been proposed as a scaling factor for comparing experimental results collected under different test conditions and for extrapolating short-term results to longer periods of time. Developing an understanding of the effect of SAN is needed for modeling experimental results where SA/V ranges in value or may vary during experiments. It is also useful to understand the effect of SA/V for modeling natural systems where this value almost certainly varies, such as during the hydrothermal diagenesis of natural glasses or projecting the long-term reaction of water and borosilicate nuclear waste glass in a geologic repository.

Training Soft Skills to Project Managers An Experience Report

2012 ◽  
Vol 3 (2) ◽  
pp. 84-88 ◽  
Author(s):  
Anne Kramer
Keyword(s):  
Time Budget ◽  
Leadership Competencies ◽  
Project Managers ◽  
Project Manager ◽  
Point Of View ◽  
Limiting Factor ◽  
Short Term ◽  
Software Projects

The success of software projects is driven by the magical triangle between time, budget, and quality. While short term thinking focuses on time and budget, it is quality that has the most important impact on long term customer satisfaction. Thus, providing good quality software is crucial for success. Quality is influenced by several factors. It depends on the entire software development process and related activities (e.g., requirements management, configuration management, design controls, etc.). However, quality cannot be forced from outside. It is well known, but often forgotten, that it is the team and its relation to the project manager that decides on success or failure of a project. Improving the skills of the project managers improves the quality of the products. The limiting factor usually is not related to technical skills that can be trained quite easily. In fact, project management is all about communication and leadership competencies which are far more difficult (but not impossible) to train. In this paper, the author reports on experiences with this kind of training from an industrial point of view. In particular, the author describes what was most helpful and where the major difficulties lay.

Ecological Effects of Acid Deposition Upon Peatlands: A Neglected Field in "Acid-Rain" Research

1984 ◽  
Vol 41 (8) ◽  
pp. 1256-1268 ◽  
Author(s):  
Eville Gorham ◽  
Suzanne E. Bayley ◽  
David W. Schindler
Keyword(s):  
Acid Rain ◽  
Acid Deposition ◽  
Nutrient Availability ◽  
Experimental Studies ◽  
Metal Mobilization ◽  
Mass Balances ◽  
Short Term ◽  
Hydrological Changes

Certain types of peatlands are probably highly susceptible to anthropogenic acidification, yet very little research is being done on the vulnerability of bogs and fens to acid deposition. We have documented the need for such research and for studies of the role of acidification — natural and anthropogenic — in determining nutrient availability, metal mobilization, and biogeochemical cycling by fauna and microflora. Possible effects of hydrological changes, and of drainage from acid peatlands to lakes and streams, are noted. We provide an outline of possible responses of plants and animals to acidification; these should be investigated at species, community, and ecosystem levels. Studies of peatlands as possible sources of the gaseous precursors of acid deposition are needed. Different approaches to examining the responses of peatlands to acid deposition include geographical surveys, experimental studies, short-term, long-term, and paleoecological investigations, and analysis of biogeochemical mass-balances. Finally, we emphasize the need for inclusive studies of peatlands in relation to surrounding uplands and to the streams and lakes that receive their drainage.

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