Structural Features
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2021 ◽  
Vol 8 ◽  
Author(s):  
Xinxin Lv ◽  
Yan Hong ◽  
Qiwei Zhou ◽  
Chengchen Jiang

In this study, the in vitro digestibility of corn starch with different amylose content was determined. The results showed that waxy corn starch (WCS) and corn starch (CS) have the highest digestibility, while high amylose corn starch (HACS) has a higher content of resistant starch (RS). Besides being related to amylose content, RS content is also closely related to particle shape, debranched fine structure, molecular structure, and semi-crystalline structure. HACS can maintain a complete particle structure after gelatinization and enzymolysis; differential scanning calorimetry showed a positive correlation between gelatinization enthalpy and RS content. As the amylose content increased, the content of fa (DP 6–12) decreased, while the content of fb2 (DP 25–36) and fb3 (DP ≥ 37) increased, which in-turn decreased the cluster polymer formed by short branch chains, and the formation of more hydrogen bonds between long chain branches improved starch stability. D, which characterizes the compactness of starch semi-crystalline structure, increased with the increase of RS content. HACS 60 with the highest RS content had a unique surface fractal structure between 7.41 < d (2π/q) < 10.58 nm, indicating that the dense structure is effective in maintaining the RS content.


2021 ◽  
Author(s):  
Jingqian Wang ◽  
Zhao Liu ◽  
Xinming Gao ◽  
Chen Du ◽  
Congcong Hou ◽  
...  

Abstract KIF17, which belongs to the kinesin-2 protein family, plays an indispensable role in mammalian spermiogenesis. However, the role of KIF17 in fish spermatid remodeling during spermiogenesis remains poorly understood. Therefore, we aimed to study the role of KIF17 in spermatid remodeling during Larimichthys crocea (L. crocea) spermiogenesis. The kif17 cDNA sequence, 3247 bp in length, was cloned from L. crocea testis, which consisted of a 347 bp 5ʹ-untranslated region (UTR), 413 bp 3ʹ -UTR, and 2487 bp open reading frame. Bioinformatic analyses revealed that KIF17 obtained from L. crocea (Lc-KIF17) exhibited a high sequence identity compared with those from other teleosts and possessed the structural features of other kinesin-2 proteins. Based on structural similarity, we speculate that the role of Lc-KIF17 may be similar to that of KIF17 in other animals. Lc-kif17 mRNA was diffusely expressed in L. crocea tissues and was highly expressed in the testis, especially at stage IV testicular development. Immunofluorescence analysis revealed that Lc-KIF17 signals colocalized with β-tubulin signals and migrated from the perinuclear cytoplasm to the side of the nucleus where the tail forms during spermiogenesis. These findings revealed that KIF17 may be involved in L. crocea spermiogenesis. In particular, KIF17 may participate in spermatid remodeling by interacting with perinuclear microtubules during L. crocea spermiogenesis. Collectively, this study contributes to an improved understanding of the mechanism underlying L. crocea spermiogenesis and provides a basis for further research on L. crocea reproduction and development.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3715
Author(s):  
Yuri D. Ivanov ◽  
Kristina A. Malsagova ◽  
Vladimir P. Popov ◽  
Igor N. Kupriyanov ◽  
Tatyana O. Pleshakova ◽  
...  

The application of micro-Raman spectroscopy was used for characterization of structural features of the high-k stack (h-k) layer of “silicon-on-insulator” (SOI) nanowire (NW) chip (h-k-SOI-NW chip), including Al2O3 and HfO2 in various combinations after heat treatment from 425 to 1000 °C. After that, the NW structures h-k-SOI-NW chip was created using gas plasma etching optical lithography. The stability of the signals from the monocrine phase of HfO2 was shown. Significant differences were found in the elastic stresses of the silicon layers for very thick (>200 nm) Al2O3 layers. In the UV spectra of SOI layers of a silicon substrate with HfO2, shoulders in the Raman spectrum were observed at 480–490 cm−1 of single-phonon scattering. The h-k-SOI-NW chip created in this way has been used for the detection of DNA-oligonucleotide sequences (oDNA), that became a synthetic analog of circular RNA–circ-SHKBP1 associated with the development of glioma at a concentration of 1.1 × 10−16 M. The possibility of using such h-k-SOI NW chips for the detection of circ-SHKBP1 in blood plasma of patients diagnosed with neoplasm of uncertain nature of the brain and central nervous system was shown.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3602
Author(s):  
Enrico Squizzato ◽  
Caterina Sanna ◽  
Antonella Glisenti ◽  
Paola Costamagna

In the present work, structural and catalytic characterization was performed on La0.6Sr0.4MnO3 (LSM) nanofibers. The LSM nanofibers were obtained using the electrospinning technique. For comparison, LSM powders with identical composition were characterized as well. The LSM powders were prepared through a self-combustion citrate-based procedure. SEM, EDX, XRD, and BET investigations were carried out on both LSM nanofibers and powders, pointing out the different structural features. The LSM nanofibers showed a higher surface area than the LSM powders and a lower presence of strontium oxide on the surface. Results of the H2-Temperature Programmed Reduction (TPR) tests showed evidence of a higher reactivity of the nanofibers compared to the powders. The catalytic characterization was performed utilizing a methane oxidation activity test, revealing a better catalytic performance of the LSM nanofibers: at 800 °C. The methane conversion achieved with the LSM nanofibers was 73%, which compared well with the 50% obtained with powders at 900 °C.


2021 ◽  
Author(s):  
Mikhail A. Moldovan ◽  
Zoe Chervontseva ◽  
Daria Nogina ◽  
Mikhail Gelfand

RNA editing in the form of substituting adenine to inosine (A-to-I editing) is the most frequent type of RNA editing, observed in many metazoan species. A-to-I editing sites form clusters in most studied species, and editing at clustered sites depends on editing of the adjacent sites. Although functionally important in some specific cases, A-to-I editing in most considered species is rare, the exception being soft-bodied cephalopods (coleoids), where tens of thousands of potentially important A-to-I editing sites have been identified, making coleoids an ideal object for studying of general properties and evolution of A-to-I editing sites. Here, we apply several diverse techniques to demonstrate a strong tendency of coleoid RNA editing sites to cluster along the transcript. We identify three distinct types of editing site clusters, varying in size, and describe RNA structural features and mechanisms likely underlying formation of these clusters. In particular, these observations may resolve the paradox of sequence conservation at large distances around editing sites.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yubao Zhao ◽  
Peng Zhang ◽  
Zhenchun Yang ◽  
Lina Li ◽  
Jingyu Gao ◽  
...  

AbstractSolar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride framework with sodium cyanaminate moiety, affording a H2O2 production rate of 18.7 μmol h −1 mg−1 and an apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed, and some previously unknown structural features and interactions are substantiated via experimental and theoretical methods. The structural features of cyanamino group and pyridinic nitrogen-coordinated soidum in the framework promote photon absorption, alter the energy landscape of the framework and improve charge separation efficiency, enhance surface adsorption of dioxygen, and create selective 2e− oxygen reduction reaction surface-active sites. Particularly, an electronic coupling interaction between O2 and surface, which boosts the population and prolongs the lifetime of the active shallow-trapped electrons, is experimentally substantiated.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3689
Author(s):  
Khaled D. Khalil ◽  
Sayed M. Riyadh ◽  
Mariusz Jaremko ◽  
Thoraya A. Farghaly ◽  
Mohamed Hagar

Recently, the development of nanocatalysts based on naturally occurring polysaccharides has received a lot of attention. Chitosan (CS), as a biodegradable and biocompatible polysaccharide, is considered to be an excellent template for the design of a hybrid biopolymer-based metal oxide nanocomposite. In this case, lanthanum oxide nanoparticles doped with chitosan at different weight percentages (5, 10, 15, and 20 wt% CS/La2O3) were prepared via a simple solution casting method. The prepared CS/La2O3 nanocomposite solutions were cast in a Petri dish in order to produce the developed catalyst, which was shaped as a thin film. The structural features of the hybrid nanocomposite film were studied by FTIR, SEM, and XRD analytical tools. FTIR spectra confirmed the presence of the major characteristic peaks of chitosan, which were modified by interaction with La2O3 nanoparticles. Additionally, SEM graphs showed dramatic morphological changes on the surface of chitosan, which is attributed to surface adsorption with La2O3 molecules. The prepared CS/La2O3 nanocomposite film (15% by weight) was investigated as an effective, recyclable, and heterogeneous base catalyst in the synthesis of pyridines and pyrazoles. The nanocomposite used was sufficiently stable and was collected and reused more than three times without loss of catalytic activity.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1579
Author(s):  
Ricardo Almeida ◽  
Eduardo Ferraz ◽  
Julio Santarén ◽  
José A. F. Gamelas

The surface properties of two sepiolite samples and one palygorskite sample were compared using inverse gas chromatography (IGC). Samples were previously conditioned at appropriate temperatures for the removal of all zeolitic water. Dispersive (or Lifshitz–van der Waals) component of the surface energy (γsd), specific interactions (−ΔGas) with π electron donor bases (1-alkenes), and nanomorphology indices (IMχT) based on the injections of cycloalkanes and a branched alkane were measured. From IGC data, at 240 °C, it was found that the palygorskite was clearly distinguished from the sepiolites. The palygorskite possessed a lower γsd, larger −ΔGas with 1-alkenes, and remarkably higher IMχT. Slight differences could also be observed between the two sepiolite samples with the same origin. The results were rationalized in terms of the structural features of the two studied minerals. The larger channels of the sepiolite allow for a better insertion of the n-alkanes (longer retention times) while excluding the bulkier probes, such as cyclooctane or 2,2,4-trimethylpentane. Accordingly, the corresponding γsd values were larger and the IMχT values were lower (higher surface nanoroughness) for the sepiolites. Regarding Lewis acid–base properties, all the sample’s surfaces evidenced a very strong amphoteric character. The present results highlight the potential of the evaluated samples for, e.g., adsorption processes with volatile organic compounds or matrix–filler interactions regarding the production of composite structures with Lewis acid–base matrices.


2021 ◽  
pp. 107755872110247
Author(s):  
Michaela Kerrissey ◽  
Maike Tietschert ◽  
Zhanna Novikov ◽  
Hassina Bahadurzada ◽  
Anna D. Sinaiko ◽  
...  

More is known about the structural features of health system integration than the social features—elements of normative integration (alignment of norms) and interpersonal integration (collaboration among professionals and with patients). We surveyed practice managers and 1,360 staff and physicians at 59 practice sites within 17 health systems (828 responses; 61%). Building on prior theory, we developed and established the psychometric properties of survey measures describing normative and interpersonal integration. Normative and interpersonal integration were both consistently related to better provider experience, perceived care quality, and clinical integration (e.g., a 1-point increase in a practice’s normative integration was associated with 0.53-point higher job satisfaction and 0.77-point higher perceived care quality in the practice, measured on 1 to 5 scales, p < .01). Variation in social features of integration may help explain why some health systems better integrate care, pointing to normative and interpersonal integration as potential resources for improvement.


2021 ◽  
Vol 22 (12) ◽  
pp. 6420
Author(s):  
Himanshu Pandey ◽  
Mary Popov ◽  
Alina Goldstein-Levitin ◽  
Larisa Gheber

Bipolar kinesin-5 motor proteins perform multiple intracellular functions, mainly during mitotic cell division. Their specialized structural characteristics enable these motors to perform their essential functions by crosslinking and sliding apart antiparallel microtubules (MTs). In this review, we discuss the specialized structural features of kinesin-5 motors, and the mechanisms by which these features relate to kinesin-5 functions and motile properties. In addition, we discuss the multiple roles of the kinesin-5 motors in dividing as well as in non-dividing cells, and examine their roles in pathogenetic conditions. We describe the recently discovered bidirectional motility in fungi kinesin-5 motors, and discuss its possible physiological relevance. Finally, we also focus on the multiple mechanisms of regulation of these unique motor proteins.


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