Purification of acrylamide from polymerization inhibitors   in the manufacture of high quality flocculants based on polyacrylamide

Polyacrylamide and its copolymers are widely used as flocculating agents for the separation of industrial suspensions. The formation of high molecular weight polymers depends on the content of various impurities present in the monomer. The article presents the scientific and practical information on the production of acrylamide by sulfuric acid method of hydration of nitrile acrylic acid in the form of an aqueous solution of different concentrations and a more modern heterogeneously catalytic method of hydration of acrylonitrile using as catalysts with variable valence. Ways to get different impurities in the stages of production of acrylamide with the purpose of applying appropriate methods for its purification. Laboratory studies of the purification of an aqueous solution of acrylamide from iron ions were carried out as an element of inhibition of the premature polymerization process.

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The physical environment mediates male harm and its effect on selection in females

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0424 ◽

2017 ◽

Vol 284 (1858) ◽

pp. 20170424 ◽

Cited By ~ 38

Author(s):

Li Yun ◽

Patrick J. Chen ◽

Amardeep Singh ◽

Aneil F. Agrawal ◽

Howard D. Rundle

Keyword(s):

Drosophila Melanogaster ◽

Sexual Selection ◽

Physical Environment ◽

Selective Advantage ◽

Laboratory Studies ◽

Male Choice ◽

Female Fitness ◽

High Quality ◽

Evolutionary Consequences ◽

Natural And Sexual Selection

Recent experiments indicate that male preferential harassment of high-quality females reduces the variance in female fitness, thereby weakening natural selection through females and hampering adaptation and purging. We propose that this phenomenon, which results from a combination of male choice and male-induced harm, should be mediated by the physical environment in which intersexual interactions occur. Using Drosophila melanogaster , we examined intersexual interactions in small and simple (standard fly vials) versus slightly more realistic (small cages with spatial structure) environments. We show that in these more realistic environments, sexual interactions are less frequent, are no longer biased towards high-quality females, and that overall male harm is reduced. Next, we examine the selective advantage of high- over low-quality females while manipulating the opportunity for male choice. Male choice weakens the viability advantage of high-quality females in the simple environment, consistent with previous work, but strengthens selection on females in the more realistic environment. Laboratory studies in simple environments have strongly shaped our understanding of sexual conflict but may provide biased insight. Our results suggest that the physical environment plays a key role in the evolutionary consequences of sexual interactions and ultimately the alignment of natural and sexual selection.

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Optimization of high molecular weight DNA extraction methods in shrimp for a long-read sequencing platform

PeerJ ◽

10.7717/peerj.10340 ◽

2020 ◽

Vol 8 ◽

pp. e10340

Author(s):

Pacharaporn Angthong ◽

Tanaporn Uengwetwanit ◽

Wirulda Pootakham ◽

Kanchana Sittikankaew ◽

Chutima Sonthirod ◽

...

Keyword(s):

Molecular Weight ◽

Genomic Dna ◽

Extraction Methods ◽

Marine Organisms ◽

High Quality ◽

Sequencing Platform ◽

Global Food Security ◽

Long Read ◽

Ctab Method ◽

Global Food

Marine organisms are important to global food security as they are the largest source of animal proteins feeding mankind. Genomics-assisted aquaculture can increase yield while preserving the environment to ensure sufficient and sustainable production for global food security. However, only few high-quality genome sequences of marine organisms, especially shellfish, are available to the public partly because of the difficulty in the sequence assembly due to the complex nature of their genomes. A key step for a successful genome sequencing is the preparation of high-quality high molecular weight (HMW) genomic DNA. This study evaluated the effectiveness of five DNA extraction protocols (CTAB, Genomic-tip, Mollusc DNA, TIANamp Marine Animals DNA, and Sbeadex livestock kits) in obtaining shrimp HMW DNA for a long-read sequencing platform. DNA samples were assessed for quality and quantity using a Qubit fluorometer, NanoDrop spectrophotometer and pulsed-field gel electrophoresis. Among the five extraction methods examined without further optimization, the Genomic-tip kit yielded genomic DNA with the highest quality. However, further modifications of these established protocols might yield even better DNA quality and quantity. To further investigate whether the obtained genomic DNA could be used in a long-read sequencing application, DNA samples from the top three extraction methods (CTAB method, Genomic-tip and Mollusc DNA kits) were used for Pacific Biosciences (PacBio) library construction and sequencing. Genomic DNA obtained from Genomic-tip and Mollusc DNA kits allowed successful library construction, while the DNA obtained from the CTAB method did not. Genomic DNA isolated using the Genomic-tip kit yielded a higher number of long reads (N50 of 14.57 Kb) than those obtained from Mollusc DNA kits (N50 of 9.74 Kb). Thus, this study identified an effective extraction method for high-quality HMW genomic DNA of shrimp that can be applied to other marine organisms for a long-read sequencing platform.

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Steady-State Modeling and Control of Molecular Weight Distributions in a Styrene Polymerization Process Based on B-Spline Neural Networks

Advances in Neural Networks – ISNN 2007 - Lecture Notes in Computer Science ◽

10.1007/978-3-540-72383-7_39 ◽

2007 ◽

pp. 329-338 ◽

Cited By ~ 2

Author(s):

Jinfang Zhang ◽

Hong Yue

Keyword(s):

Neural Networks ◽

Molecular Weight ◽

Steady State ◽

Polymerization Process ◽

Styrene Polymerization ◽

Modeling And Control ◽

B Spline ◽

Molecular Weight Distributions ◽

Weight Distributions ◽

And Control

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Complexation of arsenate to humic acid with different molecular weight fractions in aqueous solution

Journal of Environmental Science and Health Part A ◽

10.1080/10934529.2021.2006544 ◽

2021 ◽

pp. 1-7

Author(s):

Shifeng Li ◽

Feng Lu ◽

Hongtao Lv ◽

Yang Zhou ◽

Mario A. Gomez ◽

...

Keyword(s):

Aqueous Solution ◽

Molecular Weight ◽

Humic Acid ◽

Molecular Weight Fractions ◽

Different Molecular Weight

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Low Molecular Weight Gelators Based on Functionalized l-Dopa Promote Organogels Formation

Gels ◽

10.3390/gels5020027 ◽

2019 ◽

Vol 5 (2) ◽

pp. 27 ◽

Cited By ~ 2

Author(s):

Demetra Giuri ◽

Nicola Zanna ◽

Claudia Tomasini

Keyword(s):

Aqueous Solution ◽

Molecular Weight ◽

Rheological Properties ◽

Rhodamine B ◽

Lauric Acid ◽

Water Solution ◽

Preliminary Test ◽

Low Molecular Weight ◽

Coupling Reactions ◽

Low Molecular Weight Gelators

We prepared the small pseudopeptide Lau-l-Dopa(OBn)2-d-Oxd-OBn (Lau = lauric acid; l-Dopa = l-3,4-dihydroxyphenylalanine; d-Oxd = (4R,5S)-4-methyl-5-carboxyl-oxazolidin-2-one; Bn = benzyl) through a number of coupling reactions between lauric acid, protected l-Dopa and d-Oxd with an excellent overall yield. The ability of the product to form supramolecular organogels has been tested with different organic solvents of increasing polarity and compared with the results obtained with the small pseudopeptide Fmoc-l-Dopa(OBn)2-d-Oxd-OBn. The mechanical and rheological properties of the organogels demonstrated solvent-dependent properties, with a storage modulus of 82 kPa for the ethanol organogel. Finally, to have a preliminary test of the organogels’ ability to adsorb pollutants, we treated a sample of the ethanol organogel with an aqueous solution of Rhodamine B (RhB) for 24 h. The water solution slowly lost its pink color, which became trapped in the organogel.

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