Autotrophic denitrification for combined hydrogen sulfide removal from biogas and post-denitrification

2002 ◽  
Vol 45 (10) ◽  
pp. 349-356 ◽  
Author(s):  
R. Kleerebezem ◽  
R. Mendezà
Keyword(s):  
Hydrogen Sulfide ◽  
Electron Donor ◽  
Sulfide Oxidation ◽  
Experimental Studies ◽  
Future Research ◽  
Organic Substrates ◽  
Autotrophic Denitrification ◽  
Equilibrium Equations ◽  
Anaerobic Reactor ◽  
Hydrogen Sulfide Removal

In this paper we describe an alternative flow-chart for full treatment of wastewaters rich in organic substrates, ammonia (or organic nitrogen), and sulfate, such as those generated in fish cannery industries. Biogas generated during anaerobic pretreatment of these wastewaters is rich in hydrogen sulfide that needs to be removed to enable application of the biogas. Nitrogen elimination is traditionally achieved by subsequent nitrification and denitrification of the effluent of the anaerobic reactor. Alternatively, the hydrogen sulfide in the biogas can be applied as an electron donor in an autotrophic post-denitrification step. In order to study whether sufficient hydrogen sulfide containing biogas for denitrification was produced in the anaerobic reactor, the biogas composition as a function of the anaerobic reactor-pH was estimated based on a typical wastewater composition and chemical equilibrium equations. It is demonstrated that typical sulfate and nitrogen concentrations in fish cannery wastewater are highly appropriate for application of autotrophic post-denitrification. A literature review furthermore suggested that the kinetic parameters for autotrophic denitrification by Thiobacillus denitrificans represent no bottleneck for its application. Initial experimental studies in fixed-film reactors were conducted with sodium sulfide and nitrate as an electron donor-acceptor couple. The results revealed that only moderate volumetric treatment capacities (< 1 g-NO3-N L−1 day−1) could be achieved. Mass balances suggested that incomplete sulfide oxidation to elemental sulfur occurred, limiting biomass retention and the treatment capacity of the reactor. Future research should clarify the questions concerning product formation from sulfide oxidation.

Hydrogen Sulfide Removal from Biogas and Sulfur Production by Autotrophic Denitrification in a Gas-Lift Bioreactor

2020 ◽  
Vol 8 (28) ◽  
pp. 10480-10489 ◽  
Author(s):  
José J. González-Cortés ◽  
Sandra Torres-Herrera ◽  
Fernando Almenglo ◽  
Martín Ramírez ◽  
Domingo Cantero
Keyword(s):  
Hydrogen Sulfide ◽  
Autotrophic Denitrification ◽  
Sulfide Removal ◽  
Hydrogen Sulfide Removal ◽  
Gas Lift

RECLAMATION AND CULVERT CROSSINGS MADE OF CORRUGATED PIPES ON SPAWNING STREAMS

2020 ◽  
pp. 68-77
Author(s):  
O.N. CHERNYKH ◽  
◽  
A.V. RBURLACHENKO
Keyword(s):  
Single Point ◽  
Experimental Studies ◽  
Fish Passage ◽  
Future Research ◽  
Fish Stocks ◽  
Metal Structures ◽  
Natural Reproduction ◽  
Spiral Shape ◽  
Corrugated Metal ◽  
Spawning Streams

Recommendations are presented for solving issues that arise in the design and operation of tubular transport crossings of corrugated metal structures through spawning streams while ensuring the safety and natural reproduction of fish stocks. There are discussed the results of experimental studies of culverts made of metal corrugated pipes with a normal and spiral shape of corrugation the bottom of which is buried and filled with suitable granular material to the level of the natural channel of a small watercourse. It is established that when 10% of the area of the corrugated pipe is occupied by stone filling, its throughput is reduced by about 10-12%. Based on the review of the existing literature and the results of laboratory experiments, data is provided to estimate the values of the roughness coefficients of the composite cross-section of a single-point junction and directions for future research on culvert reclamation are outlined. Studying of the structure of the velocity distribution in culverts can lead to the improved conditions for fish passage without installing special structural elements in the transit path of the fish passage structure.

Amruthapala (Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter): A Comprehensive Review on Diversity, Therapeutic Uses, and Valorization of Bioactive Constituents

2019 ◽  
Vol 20 (5) ◽  
pp. 376-389 ◽  
Author(s):  
Sonali Mishra ◽  
Nupur Srivastava ◽  
Velusamy Sundaresan ◽  
Karuna Shanker
Keyword(s):  
Secondary Metabolite ◽  
Current Knowledge ◽  
Experimental Studies ◽  
Critical Discussion ◽  
Future Research ◽  
Bioactive Constituents ◽  
Medicinal Uses ◽  
Comprehensive Review ◽  
Therapeutic Uses ◽  
Decalepis Arayalpathra

Background: Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter is used primarily for nutrition besides its therapeutic values. Traditional preparations/formulations from its tuber are used as a vitalizer and blood purifier drink. The folklore medicinal uses cover inflammation, cough, wound healing, antipyretic, and digestive system management. A comprehensive review of the current understanding of the plant is required due to emerging concerns over its safety and efficacy. Objective: The systematic collection of the authentic information from different sources with the critical discussion is summarised in order to address various issues related to botanical identity, therapeutic medicine, nutritional usage, phytochemical, and pharmacological potentials of the D. arayalpathra. Current use of traditional systems of medicine can be used to expand future research opportunities. Materials and Methods: Available scripted information was collected manually, from peered review research papers and international databases viz. Science Direct, Google Scholar, SciFinder, Scopus, etc. The unpublished resources which were not available in database were collected through the classical books of ‘Ayurveda’ and ‘Siddha’ published in regional languages. The information from books, Ph.D. and MSc dissertations, conference papers and government reports were also collected. We thoroughly screened the scripted information of classical books, titles, abstracts, reports, and full-texts of the journals to establish the reliability of the content. Results: Tuber bearing vanilla like signature flavor is due to the presence of 2-hydroxy-4-methoxybenzaldehyde (HMB). Among five other species, Decalepis arayalpathra (DA) has come under the ‘critically endangered’ category, due to over-exploitation for traditional, therapeutic and cool drink use. The experimental studies proved that it possesses gastro-protective, anti-tumor, and antiinflammatory activities. Some efforts were also made to develop better therapeutics by logical modifications in 2-Hydroxy-4-methoxy-benzaldehyde, which is a major secondary metabolite of D. arayalpathra. ‘Amruthapala’ offers the enormous opportunity to develop herbal drink with health benefits like gastro-protective, anti-oxidant and anti-inflammatory actions. Results: The plant has the potential to generate the investigational new lead (IND) based on its major secondary metabolite i.e. 2-Hydroxy-4-methoxy-benzaldehyde. The present mini-review summarizes the current knowledge on Decalepis arayalpathra, covering its phytochemical diversity, biological potentials, strategies for its conservation, and intellectual property rights (IPR) status. Chemical Compounds: 2-hydroxy-4-methoxybenzaldehyde (Pubchem CID: 69600), α-amyrin acetate (Pubchem CID: 293754), Magnificol (Pubchem CID: 44575983), β-sitosterol (Pubchem CID: 222284), 3-hydroxy-p-anisaldehyde (Pubchem CID: 12127), Naringenin (Pubchem CID: 932), Kaempferol (Pubchem CID: 5280863), Aromadendrin (Pubchem CID: 122850), 3-methoxy-1,2-cyclopentanedione (Pubchem CID: 61209), p-anisaldehyde (Pubchem CID: 31244), Menthyl acetate (Pubchem CID: 27867), Benzaldehyde (Pubchem CID: 240), p-cymene (Pubchem CID: 7463), Salicylaldehyde (Pubchem CID: 6998), 10-epi-γ-eudesmol (Pubchem CID: 6430754), α -amyrin (Pubchem CID: 225688), 3-hydroxy-4-methoxy benzaldehyde (Pubchem CID: 12127).

scholarly journals Local Anesthetics and Recurrence after Cancer Surgery-What’s New? A Narrative Review

2021 ◽  
Vol 10 (4) ◽  
pp. 719
Author(s):  
Sarah D. Müller ◽  
Jonathan S. H. Ziegler ◽  
Tobias Piegeler
Keyword(s):  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Local Anesthetics ◽  
Experimental Studies ◽  
Perioperative Period ◽  
Cancer Surgery ◽  
Narrative Review ◽  
Future Research ◽  
Inflammatory Stress ◽  
Research Activities

The perioperative use of regional anesthesia and local anesthetics is part of almost every anesthesiologist’s daily clinical practice. Retrospective analyses and results from experimental studies pointed towards a potential beneficial effect of the local anesthetics regarding outcome—i.e., overall and/or recurrence-free survival—in patients undergoing cancer surgery. The perioperative period, where the anesthesiologist is responsible for the patients, might be crucial for the further course of the disease, as circulating tumor cells (shed from the primary tumor into the patient’s bloodstream) might form new micro-metastases independent of complete tumor removal. Due to their strong anti-inflammatory properties, local anesthetics might have a certain impact on these circulating tumor cells, either via direct or indirect measures, for example via blunting the inflammatory stress response as induced by the surgical stimulus. This narrative review highlights the foundation of these principles, features recent experimental and clinical data and provides an outlook regarding current and potential future research activities.

scholarly journals Opportunistic Large Array Propagation Models: A Comprehensive Survey

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4206
Author(s):  
Farhan Nawaz ◽  
Hemant Kumar ◽  
Syed Ali Hassan ◽  
Haejoon Jung
Keyword(s):  
Energy Efficient ◽  
Large Scale ◽  
Performance Metrics ◽  
Experimental Studies ◽  
Cooperative Transmission ◽  
Analytical Models ◽  
Future Research ◽  
Large Array ◽  
Propagation Models ◽  
Comprehensive Survey

Enabled by the fifth-generation (5G) and beyond 5G communications, large-scale deployments of Internet-of-Things (IoT) networks are expected in various application fields to handle massive machine-type communication (mMTC) services. Device-to-device (D2D) communications can be an effective solution in massive IoT networks to overcome the inherent hardware limitations of small devices. In such D2D scenarios, given that a receiver can benefit from the signal-to-noise-ratio (SNR) advantage through diversity and array gains, cooperative transmission (CT) can be employed, so that multiple IoT nodes can create a virtual antenna array. In particular, Opportunistic Large Array (OLA), which is one type of CT technique, is known to provide fast, energy-efficient, and reliable broadcasting and unicasting without prior coordination, which can be exploited in future mMTC applications. However, OLA-based protocol design and operation are subject to network models to characterize the propagation behavior and evaluate the performance. Further, it has been shown through some experimental studies that the most widely-used model in prior studies on OLA is not accurate for networks with networks with low node density. Therefore, stochastic models using quasi-stationary Markov chain are introduced, which are more complex but more exact to estimate the key performance metrics of the OLA transmissions in practice. Considering the fact that such propagation models should be selected carefully depending on system parameters such as network topology and channel environments, we provide a comprehensive survey on the analytical models and framework of the OLA propagation in the literature, which is not available in the existing survey papers on OLA protocols. In addition, we introduce energy-efficient OLA techniques, which are of paramount importance in energy-limited IoT networks. Furthermore, we discuss future research directions to combine OLA with emerging technologies.

The chemistry of stabilized clusters

1982 ◽  
Vol 308 (1501) ◽  
pp. 27-34 ◽  
Keyword(s):  
Electron Donor ◽  
Organic Molecules ◽  
Metal Cluster ◽  
Organic Substrates ◽  
Insertion Reactions ◽  
Donor Ligand ◽  
Small Organic Molecules ◽  
Wide Range ◽  
Metal Metal ◽  
High Yields

Studies of the chemistry of metal cluster complexes and, in particular, their reactions with small organic molecules, have been confined to relatively few systems. Among the reasons for this are: (i) not many clusters are easily synthesized in high yields; (ii) their reactions often give a multitude of products that are difficult to separate and characterize; (iii) the conditions required to bring about reactions often lead to fragmentation of the cluster into lower nuclearity (often mononuclear) species. One cluster whose chemistry has been extensively studied is [Os 3 H 2 (CO) 10 ]. This can be synthesized in high yields from [Os 3 (CO) 12 ] + H 2 (Knox et al. 1975) and reacts readily under mild conditions with a wide range of electron-donor molecules by virtue of its coordinative unsaturation (Shapley et al. 1975; Deeming & Hasso 1976; Adams & Golembeski 1979). Formally, one may consider that a metal—metal double bond is present, which is reduced to a single bond on coordination of an additional two-electron donor ligand such as an organophosphine. The presence of metal—hydrogen bonds in this cluster and the cluster’s ability to coordinate organic substrates enable it to undergo a wide variety of insertion reactions, leading to products that may be regarded as intermediates in the reduction of organic molecules by clusters (Deeming & Hasso 1975; Keister & Shapley 1975).

scholarly journals Does the model of additive effect in placebo research still hold true? A narrative review

JRSM Open ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 205427041668143 ◽  
Author(s):  
Katja Boehm ◽  
Bettina Berger ◽  
Ulrich Weger ◽  
Peter Heusser
Keyword(s):  
Context Effects ◽  
Experimental Studies ◽  
Additive Model ◽  
Drug Effects ◽  
Future Research ◽  
Inclusion Criteria ◽  
Integrative Study ◽  
Additive Relation ◽  
Specific Factors ◽  
Study Designs

Personalised and contextualised care has been turned into a major demand by people involved in healthcare suggesting to move toward person-centred medicine. The assessment of person-centred medicine can be most effectively achieved if treatments are investigated using ‘with versus without’ person-centredness or integrative study designs. However, this assumes that the components of an integrative or person-centred intervention have an additive relationship to produce the total effect. Beecher’s model of additivity assumes an additive relation between placebo and drug effects and is thus presenting an arithmetic summation. So far, no review has been carried out assessing the validity of the additive model, which is to be questioned and more closely investigated in this review. Initial searches for primary studies were undertaken in July 2016 using Pubmed and Google Scholar. In order to find matching publications of similar magnitude for the comparison part of this review, corresponding matches for all included reviews were sought. A total of 22 reviews and 3 clinical and experimental studies fulfilled the inclusion criteria. The results pointed to the following factors actively questioning the additive model: interactions of various effects, trial design, conditioning, context effects and factors, neurobiological factors, mechanism of action, statistical factors, intervention-specific factors (alcohol, caffeine), side-effects and type of intervention. All but one of the closely assessed publications was questioning the additive model. A closer examination of study design is necessary. An attempt in a more systematic approach geared towards solutions could be a suggestion for future research in this field.

Roots as a site of hydrogen sulfide uptake in the hydrocarbon seep vestimentiferan Lamellibrachia sp

1999 ◽  
Vol 202 (17) ◽  
pp. 2245-2257 ◽  
Author(s):  
D. Julian ◽  
F. Gaill ◽  
E. Wood ◽  
A.J. Arp ◽  
C.R. Fisher
Keyword(s):  
Hydrogen Sulfide ◽  
Total Mass ◽  
Sea Water ◽  
Tube Wall ◽  
Structural Characteristics ◽  
Sulfide Oxidation ◽  
Sulfide Concentration ◽  
Hydrocarbon Seep ◽  
Respiratory Organ ◽  
Root Tube

Vestimentiferan tubeworms have no mouth or gut, and the majority of their nutritional requirements are provided by endosymbiotic bacteria that utilize hydrogen sulfide oxidation to fix CO(2) into organic molecules. It has been assumed that all vestimentiferans obtain the sulfide, O(2) and CO(2) needed by the bacteria across the plume (gill) surface, but some live in locations where very little sulfide is available in the sea water surrounding the plume. We propose that at least some of these vestimentiferans can grow a posterior extension of their body and tube down into the sea-floor sediment, and that they can use this extension, which we call the ‘root’, to take up sulfide directly from the interstitial water. In this study of the vestimentiferan Lamellibrachia sp., found at hydrocarbon seeps in the Gulf of Mexico at depths of approximately 700 m, we measured seawater and interstitial sulfide concentrations in the hydrocarbon seep habitat, determined the structural characteristics of the root tube using transmission electron microscopy, characterized the biochemical composition of the tube wall, and measured the sulfide permeability of the root tube. We found that, while the sulfide concentration is less than 1 (μ)mol l(−)(1) in the sea water surrounding the gills, it can be over 1.5 mmol l(−)(1) at a depth of 10–25 cm in sediment beneath tubeworm bushes. The root tube is composed primarily of giant (β)-chitin crystallites (12–30 % of total mass) embedded in a protein matrix (50 % of total mass). Root tubes have a mean diameter of 1.4 mm, a mean wall thickness of 70 (μ)m and can be over 20 cm long. The tubeworm itself typically extends its body to the distal tip of the root tube. The root tube wall was quite permeable to sulfide, having a permeability coefficient at 20 degrees C of 0. 41×10(−)(3)cm s(−)(1), with root tube being 2.5 times more permeable to sulfide than trunk tube of the same diameter. The characteristics of the root suggest that it reaches down to the higher sulfide levels present in the deeper sediment and that it functions to increase the surface area available for sulfide uptake in a manner analogous to a respiratory organ.

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