bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Composition and Antioxidant, Anti-Inflammatory, and Enzyme Inhibitory Activities of an Endemic Species from Southern Algeria: Warionia saharae
Authors: Rechek Habiba , Haouat Ammar , Hamaidia Kaouther , Allal Hamza , Boudiar Tarek , Pinto Diana C. G. A. , Cardoso Susana M. , Bensouici Chawki , Soltani Noureddine , Silva Artur M. S.
Published: August 2021

Warionia saharae Benth. & Coss. (Asteraceae) is an endemic species of North Africa naturally grown in the southwest of the Algerian Sahara. In the present study, this species’ hydromethanolic leaf extract was investigated for its phenolic profile characterized by ultra-high-performance liquid chromatography coupled with a diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI/MS). Additionally, the chemical composition of W. saharae was analyzed by gas chromatography–mass spectrometry, and its antioxidant potential was assessed through five in vitro tests: DPPH● scavenging activity, ABTS●+ scavenging assay, galvinoxyl scavenging activity, ferric reducing power (FRP), and cupric reducing antioxidant capacity. The UHPLC-DAD-ESI/MS analysis allowed the detection and quantification of 22 compounds, with taxifolin as the dominant compound. The GC–MS analysis allowed the identification of 37 compounds, and the antioxidant activity data indicate that W. saharae extract has a very high capacity to capture radicals due to its richness in compounds with antioxidant capacity. The extract also showed potent α-glucosidase inhibition as well as a good anti-inflammatory activity. However, weak anti-α-amylase and anticholinesterase activities were recorded. Moreover, an in silico docking study was performed to highlight possible interactions between three significant compounds identified in W. saharae extract and α-glucosidase enzyme.
Protein C-Mannosylation and C-Mannosyl Tryptophan in Chemical Biology and Medicine
Authors: Minakata Shiho , Manabe Shino , Inai Yoko , Ikezaki Midori , Nishitsuji Kazuchika , Ito Yukishige , Ihara Yoshito
Published: August 2021

C-Mannosylation is a post-translational modification of proteins in the endoplasmic reticulum. Monomeric α-mannose is attached to specific Trp residues at the first Trp in the Trp-x-x-Trp/Cys (W-x-x-W/C) motif of substrate proteins, by the action of C-mannosyltransferases, DPY19-related gene products. The acceptor substrate proteins are included in the thrombospondin type I repeat (TSR) superfamily, cytokine receptor type I family, and others. Previous studies demonstrated that C-mannosylation plays critical roles in the folding, sorting, and/or secretion of substrate proteins. A C-mannosylation-defective gene mutation was identified in humans as the disease-associated variant affecting a C-mannosylation motif of W-x-x-W of ADAMTSL1, which suggests the involvement of defects in protein C-mannosylation in human diseases such as developmental glaucoma, myopia, and/or retinal defects. On the other hand, monomeric C-mannosyl Trp (C-Man-Trp), a deduced degradation product of C-mannosylated proteins, occurs in cells and extracellular fluids. Several studies showed that the level of C-Man-Trp is upregulated in blood of patients with renal dysfunction, suggesting that the metabolism of C-Man-Trp may be involved in human kidney diseases. Together, protein C-mannosylation is considered to play important roles in the biosynthesis and functions of substrate proteins, and the altered regulation of protein C-manosylation may be involved in the pathophysiology of human diseases. In this review, we consider the biochemical and biomedical knowledge of protein C-mannosylation and C-Man-Trp, and introduce recent studies concerning their significance in biology and medicine.
Bioassay-Guided Isolation of Two Eudesmane Sesquiterpenes from Lindera strychnifolia Using Centrifugal Partition Chromatography
Authors: Kim Ji Hoon , Jeon Je-Seung , Kim Jung Hoon , Jung Eun Ju , Lee Yun Jung , Gao En Mei , Syed Ahmed Shah , Son Rak Ho , Kim Chul Young
Published: August 2021

In this study, a centrifugal partition chromatography (CPC) separation was applied to identify antioxidant-responsive element (ARE) induction molecules from the crude extract of Lindera strychnifolia roots. CPC was operated with a two-phase solvent system composed of n-hexane-methanol-water (10:8.5:1.5, v/v/v) in dual mode (descending to ascending), which provided a high recovery rate (>95.5%) with high resolution. Then, ARE induction activity of obtained CPC fractions was examined in ARE-transfected HepG2 cells according to the weight ratios of the obtained fractions. The fraction exhibiting ARE-inducing activity was further purified by preparative HPLC that led to isolation of two eudesmane type sesquiterpenes as active compounds. The chemical structures were elucidated as linderolide U (1) and a new sesquiterpene named as linderolide V (2) by spectroscopic data. Further bioactivity test demonstrated that compounds 1 and 2 enhanced ARE activity by 22.4-fold and 7.6-fold, respectively, at 100 μM concentration while 5 μM of sulforaphane induced ARE activity 24.8-fold compared to the control.
Single Isomer N-Heterocyclic Cyclodextrin Derivatives as Chiral Selectors in Capillary Electrophoresis
Authors: Fejős Ida , Kalydi Eszter , Kukk Edit Luca , Seggio Mimimorena , Malanga Milo , Béni Szabolcs
Published: August 2021

In order to better understand the chiral recognition mechanisms of positively charged cyclodextrin (CD) derivatives, the synthesis, the pKa determination by 1H nuclear magnetic resonance (NMR)-pH titration and a comparative chiral capillary electrophoretic (CE) study were performed with two series of mono-substituted cationic single isomer CDs. The first series of selectors were mono-(6-N-pyrrolidine-6-deoxy)-β-CD (PYR-β-CD), mono-(6-N-piperidine-6-deoxy)-β-CD (PIP-β-CD), mono-(6-N-morpholine-6-deoxy)-β-CD (MO-β-CD) and mono-(6-N-piperazine-6-deoxy)-β-CD (PIPA-β-CD), carrying a pH-adjustable moiety at the narrower rim of the cavity, while the second set represented by their quaternarized, permanently cationic counterparts: mono-(6-N-(N-methyl-pyrrolidine)-6-deoxy)-β-CD (MePYR-β-CD), mono-(6-N-(N-methyl-piperidine)-6-deoxy)-β-CD (MePIP-β-CD), mono-(6-N-(N-methyl-morpholine)-6-deoxy)-β-CD (MeMO-β-CD) and mono-(6-N-(4,4-N,N-dimethyl-piperazine)-β-CD (diMePIPA-β-CD). Based on pH-dependent and selector concentration-dependent comparative studies of these single isomer N-heterocyclic CDs presented herein, it can be concluded that all CDs could successfully be applied as chiral selectors for the enantiodiscrimination of several negatively charged and zwitterionic model racemates. The substituent-dependent enantiomer migration order reversal of dansylated-valine using PIP-β-CD contrary to PYP-β-CD, MO-β-CD and PIPA-β-CD was also studied by 1H- and 2D ROESY NMR experiments.
Electronic Nose Differentiation between Quercus robur Acorns Infected by Pathogenic Oomycetes Phytophthora plurivora and Pythium intermedium
Authors: Borowik Piotr , Adamowicz Leszek , Tarakowski Rafał , Wacławik Przemysław , Oszako Tomasz , Ślusarski Sławomir , Tkaczyk Miłosz , Stocki Marcin
Published: August 2021

Identification of the presence of pathogenic oomycetes in infected plant material proved possible using an electronic nose, giving hope for a tool to assist nurseries and quarantine services. Previously, species of Phytophthora plurivora and Pythium intermedium have been successfully distinguished in germinated acorns of English oak Quercus robur L. Chemical compound analyses performed by HS-SPME/GC-MS (Headspace Solid-Phase Microextraction/Gas Chromatography–Mass Spectrometry) revealed the presence of volatile antifungal molecules produced by oak seedlings belonging to terpenes and alkanes. Compounds characteristic only of Phytophthora plurivora or Pythium intermedium were also found. Methylcarveol occurred when germinated acorns were infected with Pythium, while neophytadiene (isomer 2 and 3) occurred only when infected with Phytophthora. Moreover, isopentanol was found in acorns infected with Phytophthora, while in control, isopentyl vinyl ether was not observed anywhere else. Among the numerous volatile compounds, isopentanol only occurred in acorns infected with Phytophthora and methylcarveol in acorns infected with Pythium.
Chromone Derivatives with α-Glucosidase Inhibitory Activity from the Marine Fungus Penicillium thomii Maire
Authors: Han Shouye , Liu Yu , Liu Wan , Yang Fan , Zhang Jia , Liu Ruifeng , Zhao Fenqin , Xu Wei , Cheng Zhongbin
Published: August 2021

The fungal strain YPGA3 was isolated from the sediments of the Yap Trench and identified as Penicillium thomii. Eight new chromone derivatives, named penithochromones M−T (1–8), along with two known analogues, 9 and 10, were isolated from the strain. The structures were established by detailed analyses of the spectroscopic data. The absolute configuration of the only chiral center in compound 1 was tentatively determined by comparing the experimental and the calculated specific rotations. Compounds 7 and 8 represent the first examples of chromone derivatives featuring a 5,7-dioxygenated chromone moiety with a 9-carbon side chain. Bioassay study revealed that compounds 6–10 exhibited remarkable inhibition against α-glucosidase with IC50 values ranging from 268 to 1017 μM, which are more active than the positive control acarbose (1.3 mmol).
Aqueous Photochemistry of 2-Oxocarboxylic Acids: Evidence, Mechanisms, and Atmospheric Impact
Authors: Guzman Marcelo I. , Eugene Alexis J.
Published: August 2021

Atmospheric organic aerosols play a major role in climate, demanding a better understanding of their formation mechanisms by contributing multiphase chemical reactions with the participation of water. The sunlight driven aqueous photochemistry of small 2-oxocarboxylic acids is a potential major source of organic aerosol, which prompted the investigations into the mechanisms of glyoxylic acid and pyruvic acid photochemistry reviewed here. While 2-oxocarboxylic acids can be contained or directly created in the particles, the majorities of these abundant and available molecules are in the gas phase and must first undergo the surface uptake process to react in, and on the surface, of aqueous particles. Thus, the work also reviews the acid-base reaction that occurs when gaseous pyruvic acid meets the interface of aqueous microdroplets, which is contrasted with the same process for acetic acid. This work classifies relevant information needed to understand the photochemistry of aqueous pyruvic acid and glyoxylic acid and motivates future studies based on reports that use novel strategies and methodologies to advance this field.
Exploring Effects of Protease Choice and Protease Combinations in Enzymatic Protein Hydrolysis of Poultry By-Products
Authors: Lindberg Diana , Kristoffersen Kenneth Aase , Wubshet Sileshi Gizachew , Hunnes Linn Maria Gundersen , Dalsnes Marte , Dankel Katinka Riiser , Høst Vibeke , Afseth Nils Kristian
Published: August 2021

A study of the effects of single and combined protease hydrolysis on myofibrillar versus collagenous proteins of poultry by-products has been conducted. The aim was to contribute with knowledge for increased value creation of all constituents of these complex by-products. A rational approach was implemented for selecting proteases exhibiting the most different activity towards the major protein-rich constituents of mechanically deboned chicken residue (MDCR). An initial activity screening of 18 proteases on chicken meat, turkey tendons and MDCR was conducted. Based on weight yield, size exclusion chromatography (SEC) and SDS-PAGE, stem Bromelain and Endocut-02 were selected. Studies on hydrolysis of four different poultry by-products at 40 °C, evaluated by protein yield, SEC, and SDS-PAGE, indicate that the proteases’ selectivity difference can be utilized in tailor-making hydrolysates, enriched in either meat- and collagen-derived peptides or gelatin. Three modes of stem Bromelain and Endocut-02 combinations during hydrolysis of MDCR were performed and compared with single protease hydrolysis. All modes of the protease combinations resulted in a similar approximately 15% increase in product yield, with products exhibiting similar SEC and SDS-PAGE profiles. This shows that irrespective of the modes of combination, the use of more than one enzyme in hydrolysis of collagen-rich material can provide means to increase the total protein yield and ultimately contribute to increased value creation of poultry by-products.
Recovery of Banana Waste-Loss from Production and Processing: A Contribution to a Circular Economy
Authors: Alzate Acevedo Sasha , Díaz Carrillo Álvaro José , Flórez-López Edwin , Grande-Tovar Carlos David
Published: August 2021

Banana is a fruit grown mainly in tropical countries of the world. After harvest, almost 60% of banana biomass is left as waste. Worldwide, about 114.08 million metric tons of banana waste-loss are produced, leading to environmental problems such as the excessive emission of greenhouse gases. These wastes contain a high content of paramount industrial importance, such as cellulose, hemicellulose and natural fibers that various processes can modify, such as bacterial fermentation and anaerobic degradation, to obtain bioplastics, organic fertilizers and biofuels such as ethanol, biogas, hydrogen and biodiesel. In addition, they can be used in wastewater treatment methods by producing low-cost biofilters and obtaining activated carbon from rachis and banana peel. Furthermore, nanometric fibers commonly used in nanotechnology applications and silver nanoparticles useful in therapeutic cancer treatments, can be produced from banana pseudostems. The review aims to demonstrate the contribution of the recovery of banana production waste-loss towards a circular economy that would boost the economy of Latin America and many other countries of emerging economies.
The Effect of Hemp Cake (Cannabis sativa L.) on the Characteristics of Meatballs Stored in Refrigerated Conditions
Authors: Kotecka-Majchrzak Klaudia , Kasałka-Czarna Natalia , Spychaj Anita , Mikołajczak Beata , Montowska Magdalena
Published: August 2021

Hemp cake, a by-product of cold pressing oil from hemp seeds, is a nutritious ingredient that could be used for the production of new or reformulated meat products. The aim of this study was to determine the influence of inclusion of 0.9%, 2.6%, 4.2%, and 7.4% (w/w) hemp cake (Cannabis sativa L.) on the physicochemical and textural properties, oxidation, and sensory acceptance of cooked and vacuum-packed meatballs during refrigerated storage. The addition of 7.4% hemp cake enhanced the amount of dry matter and reduced the content of water. Lightness (L*) and redness (a*) values reduced significantly with higher levels of hemp supplementation. Regardless of the amount of hemp additive, pH, color parameters did not differ significantly during the 12 days of storage. Hemp cake significantly decreased protein and lipid oxidation: the inhibitory effect of adding 7.4% hemp cake on protein carbonyl group formation and TBARS values reached 11.16% and 36.5%, respectively, after 10 days of storage. Sensory analysis revealed that meatballs prepared with 0.9% and 2.6% hemp cake gained higher overall scores. The results indicate that hemp cake, a material considered mainly as waste, may be destined for food purposes and be an alternative ingredient for the production of sustainable meat products.
Sequence Dependent Repair of 1,N6-Ethenoadenine by DNA Repair Enzymes ALKBH2, ALKBH3, and AlkB
Authors: Qi Rui , Bian Ke , Chen Fangyi , Tang Qi , Zhou Xianhao , Li Deyu
Published: August 2021

Mutation patterns of DNA adducts, such as mutational spectra and signatures, are useful tools for diagnostic and prognostic purposes. Mutational spectra of carcinogens derive from three sources: adduct formation, replication bypass, and repair. Here, we consider the repair aspect of 1,N6-ethenoadenine (εA) by the 2-oxoglutarate/Fe(II)-dependent AlkB family enzymes. Specifically, we investigated εA repair across 16 possible sequence contexts (5′/3′ flanking base to εA varied as G/A/T/C). The results revealed that repair efficiency is altered according to sequence, enzyme, and strand context (ss- versus ds-DNA). The methods can be used to study other aspects of mutational spectra or other pathways of repair.
Two Novel Lyso-Ornithine Lipids Isolated from an Arctic Marine Lacinutrix sp. Bacterium
Authors: Kristoffersen Venke , Jenssen Marte , Jawad Heba Raid , Isaksson Johan , Hansen Espen H. , Rämä Teppo , Hansen Kine Ø. , Andersen Jeanette Hammer
Published: August 2021

The Lacinutrix genus was discovered in 2005 and includes 12 Gram-negative bacterial species. To the best of our knowledge, the secondary metabolite production potential of this genus has not been explored before, and examination of Lacinutrix species may reveal novel chemistry. As part of a screening project of Arctic marine bacteria, the Lacinutrix sp. strain M09B143 was cultivated, extracted, fractionated and tested for antibacterial and cytotoxic activities. One fraction had antibacterial activity and was subjected to mass spectrometry analysis, which revealed two compounds with elemental composition that did not match any known compounds in databases. This resulted in the identification and isolation of two novel isobranched lyso-ornithine lipids, whose structures were elucidated by mass spectrometry and NMR spectroscopy. Lyso-ornithine lipids consist of a 3-hydroxy fatty acid linked to the alpha amino group of an ornithine amino acid through an amide bond. The fatty acid chains were determined to be iso-C15:0 (1) and iso-C16:0 (2). Compound 1 was active against the Gram-positive S. agalactiae, while 2 showed cytotoxic activity against A2058 human melanoma cells.
Analysis of Thermoelectric Energy Harvesting with Graphene Aerogel-Supported Form-Stable Phase Change Materials
Authors: Yu Chengbin , Song Young Seok
Published: August 2021

Graphene aerogel-supported phase change material (PCM) composites sustain the initial solid state without any leakage problem when they are melted. The high portion of pure PCM in the composite can absorb or release a relatively large amount of heat during heating and cooling. In this study, these form-stable PCM composites were used to construct a thermoelectric power generator for collecting electrical energy under the external temperature change. The Seebeck effect and the temperature difference between the two sides of the thermal device were applied for thermoelectric energy harvesting. Two different PCM composites were used to collect the thermoelectric energy harvesting due to the different phase transition field in the heating and cooling processes. The graphene nano-platelet (GNP) filler was embedded to increase the thermal conductivities of PCM composites. Maximum output current was investigated by utilizing these two PCM composites with different GNP filler ratios. The thermoelectric energy harvesting efficiencies during heating and cooling were 62.26% and 39.96%, respectively. In addition, a finite element method (FEM) numerical analysis was conducted to model the output profiles.
Impact Fretting Wear of MoS2/C Nanocomposite Coating with Different Carbon Contents under Cycling Low Kinetic Energy
Authors: Zhou Junbo , Zhang Lin , Ding Yuan , Chen Xudong , Cai Zhenbing
Published: August 2021

MoS2/C nanocomposite coatings were deposited on a 304 stainless steel plate by unbalanced magnetron sputtering from carbon and molybdenum disulfide targets, and the target current of MoS2 was varied to prepare for coating with different carbon contents. The mechanical and tribological properties of the MoS2/C nanocomposite coating with different carbon contents were studied using a low-velocity impact wear machine based on kinetic energy control, and the substrate was used as the comparison material. The atomic content ratio of Mo to S in the MoS2/C coating prepared by unbalanced magnetron sputtering was approximately 1.3. The dynamic response and damage analysis revealed that the coating exhibited good impact wear resistance. Under the same experimental conditions, the wear depth of the MoS2/C coating was lower than that of the substrate, and the coating exhibited a different dynamic response process as the carbon content increased.
Optical Microfiber All-Optical Phase Modulator for Fiber Optic Hydrophone
Authors: Li Minwei , Yu Yang , Lu Yang , Hu Xiaoyang , Wang Yaorong , Qin Shangpeng , Lu Junyang , Yang Junbo , Zhang Zhenrong
Published: August 2021

In order to meet the needs of phase generated carrier (PGC) demodulation technology for interferometric fiber optic hydrophones, we proposed an optical microfiber all-optical phase modulator (OMAOPM) based on the photo-induced thermal phase shift effect, which can be used as a phase carrier generation component, so as to make the modulation efficiency and working bandwidth of this type of modulator satisfy the requirements of underwater acoustic signal demodulation applications. We analyzed the modulation principle of this modulator and optimized the structural parameters of the optical microfiber (OM) when the waist length and waist diameter of OM are 15 mm and 1.4 μm, respectively. The modulation amplitude of the modulator can reach 1 rad, which can meet the requirements of sensing applications. On this basis, the fiber optical hydrophone PGC-Atan demodulation system was constructed, and the simulated underwater acoustic signal test demodulation research was carried out. Experimental results showed that the system can demodulate underwater acoustic signals below 1 kHz.
Mechanical, Electrical, and Biological Properties of Mechanochemically Processed Hydroxyapatite Ceramics
Authors: Swain Sujata , Bhaskar Rakesh , Gupta Mukesh Kumar , Sharma Sonia , Dasgupta Sudip , Kumar Anuj , Kumar Pawan
Published: August 2021

The effect of the sintering temperature on densification and the resultant mechanical, electrical, and biological properties of mechanochemically processed hydroxyapatite (HAp) samples was investigated. HAp samples were sintered at 1200, 1250, and 1300 °C for 4 h, respectively. HAp samples sintered at 1250 °C showed better mechanical properties, which was attributed to their smaller grain size compared to HAp samples at higher sintering temperatures. The nearly identical value of the dielectric constant (εr) and better cell proliferation was exhibited by HAp samples sintered at 1250 and 1300 °C, respectively. At ~210 °C, in all the samples sintered at different temperatures, a dielectric anomaly was obtained, which was attributed to the phase transition temperature of the HAp system. Dielectric properties near the phase transition temperature showed a dielectric relaxation-type of behavior, which was attributed to the re-orientational motion of OH− ions in the HAp system. Higher cell proliferation and viability were exhibited by the HAp1300 samples, whereas comparatively equivalent cell growth and higher mechanical strength were observed in the HAp1250 samples.
Electronic Properties of Carbon Nanobelts Predicted by Thermally-Assisted-Occupation DFT
Authors: Seenithurai Sonai , Chai Jeng-Da
Published: August 2021

Accurate prediction of properties of large-scale multi-reference (MR) electronic systems remains difficult for traditional computational methods (e.g., the Hartree–Fock theory and Kohn–Sham density functional theory (DFT)). Recently, thermally-assisted-occupation (TAO)-DFT has been demonstrated to offer reliable description of electronic properties of various large-scale MR electronic systems. Consequently, in this work, TAO-DFT is used to unlock the electronic properties associated with C-Belt[n] (i.e., the carbon nanobelts containing n fused 12-membered carbon rings). Our calculations show that for all the system sizes reported (n = 4–24), C-Belt[n] have singlet ground states. In general, the larger the size of C-Belt[n], the more pronounced the MR character of ground-state C-Belt[n], as evident from the symmetrized von Neumann entropy and the occupation numbers of active TAO-orbitals. Furthermore, the active TAO-orbitals are delocalized along the circumference of C-Belt[n], as evident from the visualization of active TAO-orbitals.
Effect of Silica Embedding on the Structure, Morphology and Magnetic Behavior of (Zn0.6Mn0.4Fe2O4)δ/(SiO2)(100−δ) Nanoparticles
Authors: Dippong Thomas , Deac Iosif Grigore , Cadar Oana , Levei Erika Andrea
Published: August 2021

The effect of SiO2 embedding on the obtaining of single-phase ferrites, as well as on the structure, morphology and magnetic properties of (Zn0.6Mn0.4Fe2O4)δ(SiO2)100−δ (δ = 0–100%) nanoparticles (NPs) synthesized by sol-gel method was assessed. The phase composition and crystallite size were investigated by X-ray diffraction (XRD), the chemical transformations were monitored by Fourier transform infrared (FT-IR) spectroscopy, while the morphology of the NPs by transmission electron microscopy (TEM). The average crystallite size was 5.3–27.0 nm at 400 °C, 13.7–31.1 nm at 700 °C and 33.4–49.1 nm at 1100 °C. The evolution of the saturation magnetization, coercivity and magnetic anisotropy as a function of the crystallite sizes were studied by vibrating sample magnetometry (VSM) technique. As expected, the SiO2 matrix shows diamagnetic behavior accompanied by the accidentally contribution of a small percent of ferromagnetic impurities. The Zn0.6Mn0.4Fe2O4 embedded in SiO2 exhibits superparamagnetic-like behavior, whereas the unembedded Zn0.6Mn0.4Fe2O4 behaves like a high-quality ferrimagnet. The preparation route has a significant effect on the particle sizes, which strongly influences the magnetic behavior of the NPs.
Promoting the Selectivity of Pt/m-ZrO2 Ethanol Steam Reforming Catalysts with K and Rb Dopants
Authors: Martinelli Michela , Garcia Richard , Watson Caleb D. , Cronauer Donald C. , Kropf A. Jeremy , Jacobs Gary
Published: August 2021

The ethanol steam reforming reaction (ESR) was investigated on unpromoted and potassium- and rubidium-promoted monoclinic zirconia-supported platinum (Pt/m-ZrO2) catalysts. Evidence from in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) characterization indicates that ethanol dissociates to ethoxy species, which undergo oxidative dehydrogenation to acetate followed by acetate decomposition. The acetate decomposition pathway depends on catalyst composition. The decarboxylation pathway tends to produce higher overall hydrogen selectivity and is the most favored route at high alkali loading (2.55 wt.% K and higher or 4.25 wt.% Rb and higher). On the other hand, decarbonylation is a significant route for the undoped catalyst or when a low alkali loading (e.g., 0.85% K or 0.93% Rb) is used, thus lowering the overall H2 selectivity of the process. Results of in situ DRIFTS and the temperature-programmed reaction of ESR show that alkali doping promotes forward acetate decomposition while exposed metallic sites tend to facilitate decarbonylation. In previous work, 1.8 wt.% Na was found to hinder decarbonylation completely. Due to the fact that 1.8 wt.% Na is atomically equivalent to 3.1 wt.% K and 6.7 wt.% Rb, the results show that less K (2.55% K) or Rb (4.25% Rb) is needed to suppress decarbonylation; that is, more basic cations are more efficient promoters for improving the overall hydrogen selectivity of the ESR process.
Some Thermoelectric Phenomena in Copper Chalcogenides Replaced by Lithium and Sodium Alkaline Metals
Authors: Kubenova Marzhan M. , Kuterbekov Kairat A. , Balapanov Malik K. , Ishembetov Rais K. , Kabyshev Asset M. , Bekmyrza Kenzhebatyr Z.
Published: August 2021

This review presents thermoelectric phenomena in copper chalcogenides substituted with sodium and lithium alkali metals. The results for other modern thermoelectric materials are presented for comparison. The results of the study of the crystal structure and phase transitions in the ternary systems Na-Cu-S and Li-Cu-S are presented. The main synthesis methods of nanocrystalline copper chalcogenides and its alloys are presented, as well as electrical, thermodynamic, thermal, and thermoelectric properties and practical application. The features of mixed electron–ionic conductors are discussed. In particular, in semiconductor superionic copper chalcogenides, the presence of a “liquid-like phase” inside a “solid” lattice interferes with the normal propagation of phonons; therefore, superionic copper chalcogenides have low lattice thermal conductivity, and this is a favorable factor for the formation of high thermoelectric efficiency in them.
Dopamine-Conjugated Carbon Dots Inhibit Human Calcitonin Fibrillation
Authors: Wu Jhe-An , Chen Yu-Chieh , Tu Ling-Hsien
Published: August 2021

The development of biocompatible nanomaterials has become a new trend in the treatment and prevention of human amyloidosis. Human calcitonin (hCT), a hormone peptide secreted from parafollicular cells, plays a major role in calcium–phosphorus metabolism. Moreover, it can be used in the treatment of osteoporosis and Paget’s disease. Unfortunately, it tends to form amyloid fibrils irreversibly in an aqueous solution, resulting in a reduction of its bioavailability and therapeutic activity. Salmon calcitonin is the replacement of hCT as a widely therapeutic agent due to its lower propensity in aggregation and better bioactivity. Herein, we used citric acid to synthesize carbon dots (CDs) and modified their surface properties by a variety of chemical conjugations to provide different functionalized CDs. It was found that dopamine-conjugated CDs can effectively inhibit hCT aggregation especially in the fibril growth phase and dissociate preformed hCT amyloids. Although the decomposition mechanism of dopamine-conjugated CDs is not clear, it seems to be specific to hCT amyloids. In addition, we also tested dopamine-conjugated mesoporous silica nanoparticles in preventing hCT fibrillization. They also can work as inhibitors but are much less effective than CDs. Our studies emphasized the importance of the size and surface functionalization of core materials in the development of nanomaterials as emerging treatments for amyloidosis. On the other hand, proper functionalized CDs would be useful in hCT formulation.
A Study on the Stability of Carbon Nanoforms–Polyimidazolium Network Hybrids in the Conversion of CO2 into Cyclic Carbonates: Increase in Catalytic Activity after Reuse
Authors: Morena Anthony , Campisciano Vincenzo , Comès Adrien , Liotta Leonarda Francesca , Gruttadauria Michelangelo , Aprile Carmela , Giacalone Francesco
Published: August 2021

Three different carbon nanoforms (CNFs), single-walled and multi-walled carbon nanotubes (SWCNTs, MWCNTs) and carbon nanohorns (CNHs), have been used as supports for the direct polymerization of variable amounts of a bis-vinylimidazolium salt. Transmission electron microscopy confirmed that all CNFs act as templates on the growth of the polymeric network, which perfectly covers the nanocarbons forming a cylindrical (SWCNTs, MWCNTs) or spherical (CNHs) coating. The stability of these hybrid materials was investigated in the conversion of CO2 into cyclic carbonate under high temperature and CO2 pressure. Compared with the homopolymerized monomer, nanotube-based materials display an improved catalytic activity. Beside the low catalytic loading (0.05–0.09 mol%) and the absence of Lewis acid co-catalysts, all the materials showed high TON values (up to 1154 for epichlorohydrin with SW-1:2). Interestingly, despite the loss of part of the polymeric coating for crumbling or peeling, the activity increases upon recycling of the materials, and this behaviour was ascribed to their change in morphology, which led to materials with higher surface areas and with more accessible catalytic sites. Transmission electron microscopy analysis, along with different experiments, have been carried out in order to elucidate these findings.
The Role of Substrate on Thermal Evolution of Ag/TiO2 Nanogranular Thin Films
Authors: Balzano Vincenzo , Cavaliere Emanuele , Fanetti Mattia , Gardonio Sandra , Gavioli Luca
Published: August 2021

In multicomponent thin films, properties and functionalities related to post-deposition annealing treatments, such as thermal stability, optical absorption and surface morphology are typically rationalized, neglecting the role of the substrate. Here, we show the role of the substrate in determining the temperature dependent behaviour of a paradigmatic two-component nanogranular thin film (Ag/TiO2) deposited by gas phase supersonic cluster beam deposition (SCBD) on silica and sapphire. Up to 600 °C, no TiO2 grain growth nor crystallization is observed, likely inhibited by the Zener pinning pressure exerted by the Ag nanoparticles on the TiO2 grain boundaries. Above 600 °C, grain coalescence, formation of However, the two substrates steer the evolution of the film morphology and optical properties in two different directions. anatase and rutile phases and drastic modification of the optical absorption are observed. On silica, Ag is still present as NPs distributed into the TiO2 matrix, while on sapphire, hundreds of nm wide Ag aggregates appear on the film surface. Moreover, the silica-deposited film shows a broad absorption band in the visible range while the sapphire-deposited film becomes almost transparent for wavelengths above 380 nm. We discuss this result in terms of substrate differences in thermal conductivity, thermal expansion coefficient and Ag diffusivity. The study of the substrate role during annealing is possible since SCBD allows the synthesis of the same film independently of the substrate, and suggests new perspectives on the thermodynamics and physical exchanges between thin films and their substrates during heat treatments.
Antibacterial Activity of Copper Nanoparticles (CuNPs) against a Resistant Calcium Hydroxide Multispecies Endodontic Biofilm
Authors: Rojas Beatriz , Soto Nicole , Villalba Marcela , Bello-Toledo Helia , Meléndrez-Castro Manuel , Sánchez-Sanhueza Gabriela
Published: August 2021

Endodontic treatment reduces the amount of bacteria by using antimicrobial agents to favor healing. However, disinfecting all of the canal system is difficult due to its anatomical complexity and may result in endodontic failure. Copper nanoparticles have antimicrobial activity against diverse microorganisms, especially to resistant strains, and offer a potential alternative for disinfection during endodontic therapy. This study evaluated the antibacterial action of copper nanoparticles (CuNPs) on an ex vivo multispecies biofilm using plaque count compared to the antibacterial activity of calcium hydroxide Ca(OH)2. There were significant differences between the Ca(OH)2 and CuNPs groups as an intracanal dressing compared with the CuNPs groups as an irrigation solution (p < 0.0001). An increase in the count of the group exposed to 7 days of Ca(OH)2 was observed compared to the group exposed to Ca(OH)2 for 1 day. These findings differ from what was observed with CuNPs in the same period of time. Antibacterial activity of CuNPs was observed on a multispecies biofilm, detecting an immediate action and over-time effect, gradually reaching their highest efficacy on day 7 after application. The latter raises the possibility of the emergence of Ca(OH)2-resistant strains and supports the use of CuNPs as alternative intracanal medication.
Magnetic Nanoparticle-Containing Supports as Carriers of Immobilized Enzymes: Key Factors Influencing the Biocatalyst Performance
Authors: Matveeva Valentina G. , Bronstein Lyudmila M.
Published: August 2021

In this short review (Perspective), we identify key features of the performance of biocatalysts developed by the immobilization of enzymes on the supports containing magnetic nanoparticles (NPs), analyzing the scientific literature for the last five years. A clear advantage of magnetic supports is their easy separation due to the magnetic attraction between magnetic NPs and an external magnetic field, facilitating the biocatalyst reuse. This allows for savings of materials and energy in the biocatalytic process. Commonly, magnetic NPs are isolated from enzymes either by polymers, silica, or some other protective layer. However, in those cases when iron oxide NPs are in close proximity to the enzyme, the biocatalyst may display a fascinating behavior, allowing for synergy of the performance due to the enzyme-like properties shown in iron oxides. Another important parameter which is discussed in this review is the magnetic support porosity, especially in hierarchical porous supports. In the case of comparatively large pores, which can freely accommodate enzyme molecules without jeopardizing their conformation, the enzyme surface ordering may create an optimal crowding on the support, enhancing the biocatalytic performance. Other factors such as surface-modifying agents or special enzyme reactor designs can be also influential in the performance of magnetic NP based immobilized enzymes.
Glutathione Disulfide as a Reducing, Capping, and Mass-Separating Agent for the Synthesis and Enrichment of Gold Nanoclusters
Authors: Zhang Qianqian , Wang Junhua , Meng Zhao , Ling Rui , Ren Hang , Qin Weidong , Wu Zhenglong , Shao Na
Published: August 2021

Water-soluble nanoclusters, which are facilely enrichable without changes in the original properties, are highly demanded in many disciplines. In this contribution, a new class of gold nanoclusters (AuNCs) was synthesized using glutathione disulfide (GSSG) as a reducing and capping agent under intermittent heating mode. The as-prepared GSSG–AuNCs had a higher quantum yield (4.1%) compared to the conventional glutathione-protected AuNCs (1.8%). Moreover, by simply introducing the GSSG–AuNC solution to acetonitrile at a volume ratio of 1:7, a new bottom phase was formed, in which GSSG–AuNCs could be 400-fold enriched without changes in properties, with a percentage recovery higher than 99%. The enrichment approach did not need additional instruments and was potentially suitable for large-scale enrichment of nanoclusters. Further, density functional theory calculations indicated that the hydrogen bonding between GSSG and acetonitrile plays a key role for the bottom phase formation. Our work suggests that the highly emissive GSSG–AuNCs possess great potential not only in fluorescent measurements but also in other scenarios in which high-concentration AuNCs may be needed, such as catalysis, drug delivery, and electronic and optical industries.
Bovine Colostrum Supplementation Improves Bone Metabolism in an Osteoporosis-Induced Animal Model
Authors: Kydonaki Eirini K. , Freitas Laura , Fonseca Bruno M. , Reguengo Henrique , Raposo Simón Carlos , Bastos Ana R. , Fernandes Emanuel M. , Canadas Raphaël F. , Oliveira Joaquim Miguel , Correlo Vitor M. , Reis Rui L. , Vliora Maria , Gkiata Parakevi , Koutedakis Yiannis , Ntina Georgia , Pinto Rui , Carrillo Andres E. , Marques Franklim , Amorim Tânia
Published: August 2021

Osteoporosis is characterized by bone loss. The present study aims to investigate the effects of bovine colostrum (BC) on bone metabolism using ovariectomized (OVX) and orchidectomized (ORX) rat models. Twenty-seven-week-old Wistar Han rats were randomly assigned as: (1) placebo control, (2) BC supplementation dose 1 (BC1: 0.5 g/day/OVX, 1 g/day/ORX), (3) BC supplementation dose 2 (BC2: 1 g/day/OVX, 1.5 g/day/ORX) and (4) BC supplementation dose 3 (BC3: 1.5 g/day/OVX, 2 g/day/ORX). Bone microarchitecture, strength, gene expression of VEGFA, FGF2, RANKL, RANK and OPG, and bone resorption/formation markers were assessed after four months of BC supplementation. Compared to the placebo, OVX rats in the BC1 group exhibited significantly higher cortical bone mineral content and trabecular bone mineral content (p < 0.01), while OVX rats in the BC3 group showed significantly higher trabecular bone mineral content (p < 0.05). ORX rats receiving BC dose 2 demonstrated significantly higher levels of trabecular bone mineral content (p < 0.05). Serum osteocalcin in the ORX was pointedly higher in all BC supplementation groups than the placebo (BC1: p < 0.05; BC2, BC3: p < 0.001). Higher doses of BC induced significantly higher relative mRNA expression of OPG, VEGFA, FGF2 and RANKL (p < 0.05). BC supplementation improves bone metabolism of OVX and ORX rats, which might be associated with the activation of the VEGFA, FGF2 and RANKL/RANK/OPG pathways.
Effects of L-Citrulline Supplementation and Aerobic Training on Vascular Function in Individuals with Obesity across the Lifespan
Authors: Flores-Ramírez Anaisa Genoveva , Tovar-Villegas Verónica Ivette , Maharaj Arun , Garay-Sevilla Ma Eugenia , Figueroa Arturo
Published: August 2021

Children with obesity are at higher risk for developing cardiometabolic diseases that once were considered health conditions of adults. Obesity is commonly associated with cardiometabolic risk factors such as dyslipidemia, hyperglycemia, hyperinsulinemia and hypertension that contribute to the development of endothelial dysfunction. Endothelial dysfunction, characterized by reduced nitric oxide (NO) production, precedes vascular abnormalities including atherosclerosis and arterial stiffness. Thus, early detection and treatment of cardiometabolic risk factors are necessary to prevent deleterious vascular consequences of obesity at an early age. Non-pharmacological interventions including L-Citrulline (L-Cit) supplementation and aerobic training stimulate endothelial NO mediated vasodilation, leading to improvements in organ perfusion, blood pressure, arterial stiffness, atherosclerosis and metabolic health (glucose control and lipid profile). Few studies suggest that the combination of L-Cit supplementation and exercise training can be an effective strategy to counteract the adverse effects of obesity on vascular function in older adults. Therefore, this review examined the efficacy of L-Cit supplementation and aerobic training interventions on vascular and metabolic parameters in obese individuals.
Impact of Hyponatremia after Renal Transplantation on Decline of Renal Function, Graft Loss and Patient Survival: A Prospective Cohort Study
Authors: Berchtold Lena , Filzer Anja , Achermann Rita , Devetzis Vasileios , Dahdal Suzan , Bonani Marco , Schnyder Aurelia , Golshayan Dela , Amico Patrizia , Huynh-Do Uyen , de Seigneux Sophie , Arampatzis Spyridon ,   on behalf of Swiss Transplant Cohort Study Collaborators
Published: August 2021

Background: Hyponatremia is one of the most common electrolyte disorders observed in hospitalized and ambulatory patients. Hyponatremia is associated with increased falls, fractures, prolonged hospitalisation and mortality. The clinical importance of hyponatremia in the renal transplant field is not well established, so the aim of this study was to determine the relationships between hyponatremia and mortality as main outcome and renal function decline and graft loss as secondary outcome among a prospective cohort of renal transplant recipients. Methods: This prospective cohort study included 1315 patients between 1 May 2008 and 31 December 2014. Hyponatremia was defined as sodium concentration below 136 mmol/L at 6 months after transplantation. The main endpoint was mortality. A secondary composite endpoint was also defined as: rapid decline in renal function (≥5 mL/min/1.73 m2 drop of the eGFR/year), graft loss or mortality. Results: Mean sodium was 140 ± 3.08 mmol/L. 97 patients displayed hyponatremia with a mean of 132.9 ± 3.05 mmol/L. Hyponatremia at 6 months after transplantation was associated neither with mortality (HR: 1.02; p = 0.97, 95% CI: 0.47–2.19), nor with the composite outcome defined as rapid decline in renal function, graft loss or mortality (logrank test p = 0.9). Conclusions: Hyponatremia 6 months after transplantation is not associated with mortality in kidney allograft patients.
Role of Nutritional Status in the Treatment Outcome for Esophageal Squamous Cell Carcinoma
Authors: Chen Miao-Fen , Hsieh Ching-Chuan , Chen Ping-Tsung , Lu Ming-Shian
Published: August 2021

Undernourishment is reported to impair treatment response, further leading to poor prognosis for cancer patients. We aimed to investigate the role of nutritional status on the prognosis of squamous cell carcinoma (SCC) of the esophagus, and its correlation with anticancer immune responsiveness. We retrospectively reviewed 340 esophageal-SCC patients who completed curative treatment and received a nutrition evaluation by the Patient-Generated Subjective Global Assessment (PGSGA) score at the beginning and completion of neoadjuvant treatment at our hospital. The correlation between the nutritional status and various clinicopathological parameters and prognosis were examined. In addition, the role of nutritional status in the regulation of the anticancer immune response was also assessed in cancer patients and in a 4-nitroquinoline 1-oxide (4NQO)-induced esophageal tumor model. Our data revealed that malnutrition (patients with a high PGSGA score) was associated with advanced stage and reduced survival rate. Patients in the group with a high PGSGA score were correlated with the higher neutrophil-to-lymphocyte ratio, higher proportion of myeloid-derived-suppressor cells (MDSC) and increased IL-6 level. Furthermore, surgical resection brought the survival benefit to patients in the low PGSGA group, but not for the malnourished patients after neoadjuvant treatment. Using a 4NQO-induced tumor model, we found that nutrition supplementation decreased the rate of invasive tumor formation and attenuated the immune-suppressive microenvironment. In conclusion, malnutrition was associated with poor prognosis in esophageal-SCC patients. Nutritional status evaluated by PGSGA may be useful to guide treatment decisions in clinical practice. Nutritional supplementation is suggested to improve prognosis, and it might be related to augmented anticancer immune response.
Caloric Restriction per se Rather Than Dietary Macronutrient Distribution Plays a Primary Role in Metabolic Health and Body Composition Improvements in Obese Mice
Authors: Minderis Petras , Fokin Andrej , Dirmontas Mantas , Kvedaras Mindaugas , Ratkevicius Aivaras
Published: August 2021

Caloric restriction (CR) is of key importance in combating obesity and its associated diseases. We aimed to examine effects of dietary macronutrient distribution on weight loss and metabolic health in obese mice exposed to CR. Male C57BL/6J mice underwent diet-induced obesity for 18 weeks. Thereafter mice were exposed to a 6-week CR for up to 40% on either low-fat diet (LFD; 20, 60, 20% kcal from protein, carbohydrate, fat), low-carb diet (LCD; 20, 20, 60% kcal, respectively) or high-pro diet (HPD; 35, 35, 30% kcal, respectively) (n = 16 each). Ten mice on the obesogenic diet served as age-matched controls. Body composition was evaluated by tissue dissections. Glucose tolerance, bloods lipids and energy metabolism were measured. CR-induced weight loss was similar for LFD and LCD while HPD was associated with a greater weight loss than LCD. The diet groups did not differ from obese controls in hindlimb muscle mass, but showed a substantial decrease in body fat without differences between them. Glucose tolerance and blood total cholesterol were weight-loss dependent and mostly improved in LFD and HPD groups during CR. Blood triacylglycerol was lowered only in LCD group compared to obese controls. Thus, CR rather than macronutrient distribution in the diet plays the major role for improvements in body composition and glucose control in obese mice. Low-carbohydrate-high-fat diet more successfully reduces triacylglycerol but not cholesterol levels compared to isocaloric high-carbohydrate-low-fat weight loss diets.