S-Edge-rich MoxSy arrays vertically grown on carbon aerogels as superior bifunctional HER/OER electrocatalysts

Nanoscale ◽  
2019 ◽  
Vol 11 (42) ◽  
pp. 20284-20294 ◽  
Author(s):  
Yu Cheng ◽  
Pengfei Yuan ◽  
Xiaohui Xu ◽  
Sijie Guo ◽  
Kanglei Pang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Active Sites ◽  
Structural Changes ◽  
Carbon Aerogels ◽  
Clear Identification ◽  
First Time

Operando Raman spectroscopy is used for the first time for clear identification of the intrinsic active sites, intermediates and structural changes in Mo4S16@GCA.

scholarly journals Valorization of sugarcane bagasse by chemical pretreatment and enzyme mediated deconstruction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vihang S. Thite ◽  
Anuradha S. Nerurkar
Keyword(s):  
Cell Wall ◽  
Sugarcane Bagasse ◽  
Structural Changes ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Gravimetric Analysis ◽  
Chemical Pretreatment ◽  
Cell Wall Degrading Enzymes ◽  
First Time ◽  
Soluble Components

Abstract After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

scholarly journals Insights on forming N,O-coordinated Cu single-atom catalysts for electrochemical reduction CO2 to methane

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanming Cai ◽  
Jiaju Fu ◽  
Yang Zhou ◽  
Yu-Chung Chang ◽  
Qianhao Min ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Active Sites ◽  
Theoretical Calculations ◽  
High Energy ◽  
Single Atom ◽  
Faradaic Efficiency ◽  
High Energy Barrier ◽  
Catalytic Sites ◽  
Electron Reduction ◽  
First Time

AbstractSingle-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.

scholarly journals Structural and Technological Approach to Reveal the Role of the Lipid Phase in the Formation of Soy Emulsion Gels with Chia Oil

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Ana M. Herrero ◽  
Claudia Ruiz-Capillas
Keyword(s):  
Raman Spectroscopy ◽  
Structural Properties ◽  
Structural Changes ◽  
Protein Secondary Structure ◽  
Lipid Phase ◽  
Α Helix ◽  
Β Sheet ◽  
Shed Light ◽  
Chia Oil

Considerable attention has been paid to emulsion gels (EGs) in recent years due to their interesting applications in food. The aim of this work is to shed light on the role played by chia oil in the technological and structural properties of EGs made from soy protein isolates (SPI) and alginate. Two systems were studied: oil-free SPI gels (SPI/G) and the corresponding SPI EGs (SPI/EG) that contain chia oil. The proximate composition, technological properties (syneresis, pH, color and texture) and structural properties using Raman spectroscopy were determined for SPI/G and SPI/EG. No noticeable (p > 0.05) syneresis was observed in either sample. The pH values were similar (p > 0.05) for SPI/G and SPI/EG, but their texture and color differed significantly depending on the presence of chia oil. SPI/EG featured significantly lower redness and more lightness and yellowness and exhibited greater puncture and gel strengths than SPI/G. Raman spectroscopy revealed significant changes in the protein secondary structure, i.e., higher (p < 0.05) α-helix and lower (p < 0.05) β-sheet, turn and unordered structures, after the incorporation of chia oil to form the corresponding SPI/EG. Apparently, there is a correlation between these structural changes and the textural modifications observed.

Study of structural changes of gluten proteins during bread dough mixing by Raman spectroscopy

2021 ◽  
Vol 358 ◽  
pp. 129916
Author(s):  
Eloïse Lancelot ◽  
Joran Fontaine ◽  
Joëlle Grua-Priol ◽  
Ali Assaf ◽  
Gérald Thouand ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Structural Changes ◽  
Bread Dough ◽  
Gluten Proteins ◽  
Dough Mixing

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

scholarly journals Involvement of loop 5 lysine residues and the N-terminal β-hairpin of the ribotoxin hirsutellin A on its insecticidal activity

2016 ◽  
Vol 397 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Miriam Olombrada ◽  
Lucía García-Ortega ◽  
Javier Lacadena ◽  
Mercedes Oñaderra ◽  
José G. Gavilanes ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
The Other ◽  
Spatial Proximity ◽  
Ribonucleolytic Activity ◽  
The Family ◽  
Lysine Residues ◽  
Hirsutella Thompsonii ◽  
Close Spatial Proximity ◽  
High Degree

Abstract Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger, with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties. Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently, four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity, being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.

scholarly journals Structural Changes in Doped Ge2Sb2Te5 Thin Films Studied by Raman Spectroscopy

2013 ◽  
Vol 44 ◽  
pp. 82-90 ◽  
Author(s):  
S. Kozyukhin ◽  
M. Veres ◽  
H.P. Nguyen ◽  
A. Ingram ◽  
V. Kudoyarova
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Structural Changes

Fe ultra-small particles anchored on carbon aerogels to enhance the oxygen reduction reaction in Zn-air batteries

2021 ◽  
Author(s):  
Jinjin Shi ◽  
Xinxin Shu ◽  
Chensheng Xiang ◽  
Hong Li ◽  
Yang Li ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Active Sites ◽  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Superior Performance ◽  
Carbon Aerogels ◽  
Small Particles

The Fe–N4–O–Fe–N4 moiety as active sites in ultra-small Fe particles anchored on carbon aerogel exhibited superior performance towards the oxygen reduction reaction.

scholarly journals Characterization of Each St and Y Genome Chromosome of Roegneria grandis Based on Newly Developed FISH Markers

2021 ◽  
pp. 213-222
Author(s):  
Dandan Wu ◽  
Xiaoxia Zhu ◽  
Lu Tan ◽  
Haiqin Zhang ◽  
Lina Sha ◽  
...  
Keyword(s):  
Structural Changes ◽  
Distribution Patterns ◽  
Proximal Region ◽  
Genome Chromosome ◽  
High Affinity ◽  
Complete Set ◽  
Genome Analyses ◽  
First Time ◽  
Homoeologous Chromosomes

The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of <i>Roegneria</i> C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among <i>Roegneria</i> species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of <i>R. grandis</i> (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.

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