bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytoskeleton Rearrangements Modulate TRPC6 Channel Activity in Podocytes
Authors: Shalygin Alexey , Shuyskiy Leonid S. , Bohovyk Ruslan , Palygin Oleg , Staruschenko Alexander , Kaznacheyeva Elena
Published: April 2021

The actin cytoskeleton of podocytes plays a central role in the functioning of the filtration barrier in the kidney. Calcium entry into podocytes via TRPC6 (Transient Receptor Potential Canonical 6) channels leads to actin cytoskeleton rearrangement, thereby affecting the filtration barrier. We hypothesized that there is feedback from the cytoskeleton that modulates the activity of TRPC6 channels. Experiments using scanning ion-conductance microscopy demonstrated a change in migration properties in podocyte cell cultures treated with cytochalasin D, a pharmacological agent that disrupts the actin cytoskeleton. Cell-attached patch-clamp experiments revealed that cytochalasin D increases the activity of TRPC6 channels in CHO (Chinese Hamster Ovary) cells overexpressing the channel and in podocytes from freshly isolated glomeruli. Furthermore, it was previously reported that mutation in ACTN4, which encodes α-actinin-4, causes focal segmental glomerulosclerosis and solidifies the actin network in podocytes. Therefore, we tested whether α-actinin-4 regulates the activity of TRPC6 channels. We found that co-expression of mutant α-actinin-4 K255E with TRPC6 in CHO cells decreases TRPC6 channel activity. Therefore, our data demonstrate a direct interaction between the structure of the actin cytoskeleton and TRPC6 activity.
Predicting Adaptations to Resistance Training Plus Overfeeding Using Bayesian Regression: A Preliminary Investigation
Authors: Smith Robert W. , Harty Patrick S. , Stratton Matthew T. , Rafi Zad , Rodriguez Christian , Dellinger Jacob R. , Benavides Marqui L. , Johnson Baylor A. , White Sarah J. , Williams Abegale D. , Tinsley Grant M.
Published: April 2021

Relatively few investigations have reported purposeful overfeeding in resistance-trained adults. This preliminary study examined potential predictors of resistance training (RT) adaptations during a period of purposeful overfeeding and RT. Resistance-trained males (n = 28; n = 21 completers) were assigned to 6 weeks of supervised RT and daily consumption of a high-calorie protein/carbohydrate supplement with a target body mass (BM) gain of ≥0.45 kg·wk−1. At baseline and post-intervention, body composition was evaluated via 4-component (4C) model and ultrasonography. Additional assessments of resting metabolism and muscular performance were performed. Accelerometry and automated dietary interviews estimated physical activity levels and nutrient intake before and during the intervention. Bayesian regression methods were employed to examine potential predictors of changes in body composition, muscular performance, and metabolism. A simplified regression model with only rate of BM gain as a predictor was also developed. Increases in 4C whole-body fat-free mass (FFM; (mean ± SD) 4.8 ± 2.6%), muscle thickness (4.5 ± 5.9% for elbow flexors; 7.4 ± 8.4% for knee extensors), and muscular performance were observed in nearly all individuals. However, changes in outcome variables could generally not be predicted with precision. Bayes R2 values for the models ranged from 0.18 to 0.40, and other metrics also indicated relatively poor predictive performance. On average, a BM gain of ~0.55%/week corresponded with a body composition score ((∆FFM/∆BM)*100) of 100, indicative of all BM gained as FFM. However, meaningful variability around this estimate was observed. This study offers insight regarding the complex interactions between the RT stimulus, overfeeding, and putative predictors of RT adaptations.
A Pilot Clinical Study on Post-Operative Recurrence Provides Biological Clues for a Role of Candida Yeasts and Fluconazole in Crohn’s Disease
Authors: Sendid Boualem , Salvetat Nicolas , Sarter Helène , Loridant Severine , Cunisse Catherine , François Nadine , Aijjou Rachid , Gelé Patrick , Leroy Jordan , Deplanque Dominique , Jawhara Samir , Weissmann Dinah , Desreumaux Pierre , Gower-Rousseau Corinne , Colombel Jean Frédéric , Poulain Daniel
Published: April 2021

Background and aims: This study prompted by growing evidence of the relationship between the yeast Candida albicans and Crohn’s disease (CD) was intended to assess the effect of a 6-month course of the antifungal fluconazole (FCZ) on post-operative recurrence of CD. Methods: Mycological samples (mouth swabs and stools) and serum samples were collected from 28 CD patients randomized to receive either FCZ (n = 14) or placebo (n = 14) before surgical resection. Serological analysis focused on levels of calprotectin, anti-glycan antibodies, and antibody markers of C. albicans pathogenic transition. Levels of galectin-3 and mannose binding lectin (MBL) involved in C. albicans sensing and inflammation were also measured. Results: 1, 2, 3, and 6 months after surgery, endoscopy revealed recurrence in 5/12 (41.7%) patients in the FCZ group and 5/9 (55.6%) in the placebo group, the small cohort preventing any clinical conclusions. In both groups, surgery was followed by a marked decrease in C. albicans colonization and biomarkers of C. albicans pathogenic transition decreased to non-significant levels. Anti-glycan antibodies also decreased but remained significant for CD. Galectin-3 and calprotectin also decreased. Conversely, MBL levels, which inversely correlated with anti-C. albicans antibodies before surgery, remained stable. Building biostatistical multivariate models to analyze he changes in antibody and lectin levels revealed a significant relationship between C. albicans and CD. Conclusion: Several combinations of biomarkers of adaptive and innate immunity targeting C. albicans were predictive of CD recurrence after surgery, with area under the curves (AUCs) as high as 0.86. FCZ had a positive effect on biomarkers evolution. ClinicalTrials.gov ID: NCT02997059, 19 December 2016. University Hospital Lille, Ministry of Health, France. Effect of Fluconazole on the Levels of Anti-Saccharomyces cerevisiae Antibodies (ASCA) After Surgical Resection for Crohn’s Disease. Multicenter, Randomized, and Controlled in Two Parallel Groups Versus Placebo.
Firm, Industry and Macroeconomics Dynamics of Stock Returns: A Case of Pakistan Non-Financial Sector
Authors: Naseer Mirza Muhammad , Khan Muhammad Asif , Popp József , Oláh Judit
Published: April 2021

The available research literature on stock performance has primarily stressed the importance of asset price theories, macroeconomic and microeconomic, and institutional differences. However, there is still an open question: Are there any other factors those influence stock performance? This research aims to answer this question by providing new insights into industry factors along with country-level and firm-specific factors in conjunction with the stock performance of the non-financial sector firms listed at the Pakistan Stock Exchange. The study provides new insights into the prevailing research literature by considering an emerging economy, Pakistan. We find that non-financial sector firms are heterogeneous, suggesting applying a fixed effect approach for reliable estimation. To investigate the issue, data from 80 companies spanning 17 years (2004–2020) were analyzed with a fixed-effect model. Our study results revealed that firm tangibility, munificence, gross domestic product, inflation and money supply have negative, while size, growth, dynamism, Herfindahl–Hirschman index, exchange rate and oil prices have a positive relationship with financial performance. The results are robust under alternative estimation approaches and offer useful policy implications.
Emerging Economies’ Institutional Quality and International Competitiveness: A PLS-SEM Approach
Authors: Buitrago R. Ricardo E. , Barbosa Camargo María Inés , Cala Vitery Favio
Published: April 2021

The home country’s institutional framework determines the capacity to compete in the global arena. This paper discusses the linkage between institutional quality (IQ) and international competitiveness (IC). We measured institutions’ quality in emerging economies through the use of selected indicators between 2007–2017. To evaluate the proposed IQ constructs and their relationship with IC, we applied partial least squares – structural equation modeling (PLS-SEM) analysis. The model outcomes suggest that political and lack of systemic conditions have a significant and negative effect on international competitiveness, while science, technology, engineering and mathematics (STEM) resource conditions have a significant and positive effect.
Observations on Refractive Status and Risk Factors for Visual Impairment in Children with Disabilities
Authors: Holhoș Larisa Bianca , Coroi Mihaela Cristiana , Lazăr Liviu
Published: April 2021

Vision integrates all the senses and plays a fundamental role in the acquisition of different skills and the general development of a child. Recently, refractive errors and visual impairment have become serious health problems among children. Background and Objectives: The aim of this study was to identify the prevalence of refractive errors and visual impairment in children with disabilities. Moreover, this study aimed to explore the risk factors for visual impairment in children with respect to vitamin D levels, parental smoking, and the use of spectacles. Materials and Methods: We retrospectively analyzed 161 children aged 5–16 years old, divided into two groups: a group of 80 children with disabilities and a control group consisting of 81 clinically healthy children. All the children underwent refraction measurements, visual acuity testing, and plasmatic vitamin D level dosing, measured in ng/mL. Results: Refractive errors and visual impairment were found to have a higher prevalence in the group of children with disabilities than in the control group. Moreover, the plasma level of vitamin D was lower in the group of children with special health needs. Conclusions: Given the present results, children with disabilities should undergo special eye examinations as soon as possible to ensure the quality of their socio-academic lives.
Tick-Borne Encephalitis Vaccination Protects from Alimentary TBE Infection: Results from an Alimentary Outbreak
Authors: Chitimia-Dobler Lidia , Lindau Alexander , Oehme Rainer , Bestehorn-Willmann Malena , Antwerpen Markus , Drehmann Marco , Hierl Thomas , Mackenstedt Ute , Dobler Gerhard
Published: April 2021

In May 2017, a hospitalized index case of tick-borne encephalitis (TBE) was confirmed by Serology. The case was linked to alimentary infection by raw milk from a goat farm in the region of Tübingen, Baden-Württemberg, Germany, where no previous TBE cases in the area had been reported before. The TBE focus was confirmed by isolation of the TBE virus from ticks and Serological confirmation of past infection in one of the five flock goats. Additional investigations by the local public health office identified 27 consumers of goat milk at the putative period of exposure. For 20/27 exposed persons, anamnestic information was gained by the local public health office. Twelve/fourteen exposed and non-vaccinated people developed clinical illness and were confirmed as TBE cases by Serology. Five/six vaccinated and exposed people did not develop the disease. The one exposed and vaccinated person had their last TBE vaccination booster more than 15 years ago, and therefore a booster was more than 10 years overdue. None of the regularly vaccinated and exposed persons developed clinical overt TBE infection. We report the first known TBE outbreak, during which, protection by TBE vaccination against alimentary TBE infection was demonstrated.
Isolation and Characterization of Strain Exiguobacterium sp. KRL4, a Producer of Bioactive Secondary Metabolites from a Tibetan Glacier
Authors: Tedesco Pietro , Palma Esposito Fortunato , Masino Antonio , Vitale Giovanni Andrea , Tortorella Emiliana , Poli Annarita , Nicolaus Barbara , van Zyl Leonardo Joaquim , Trindade Marla , de Pascale Donatella
Published: April 2021

Extremophilic microorganisms represent a unique source of novel natural products. Among them, cold adapted bacteria and particularly alpine microorganisms are still underexplored. Here, we describe the isolation and characterization of a novel Gram-positive, aerobic rod-shaped alpine bacterium (KRL4), isolated from sediments from the Karuola glacier in Tibet, China. Complete phenotypic analysis was performed revealing the great adaptability of the strain to a wide range of temperatures (5–40 °C), pHs (5.5–8.5), and salinities (0–15% w/v NaCl). Genome sequencing identified KRL4 as a member of the placeholder genus Exiguobacterium_A and annotation revealed that only half of the protein-encoding genes (1522 of 3079) could be assigned a putative function. An analysis of the secondary metabolite clusters revealed the presence of two uncharacterized phytoene synthase containing pathways and a novel siderophore pathway. Biological assays confirmed that the strain produces molecules with antioxidant and siderophore activities. Furthermore, intracellular extracts showed nematocidal activity towards C. elegans, suggesting that strain KRL4 is a source of anthelmintic compounds.
The Impact of Pine Wood Nematode Infection on the Host Fungal Community
Authors: Liu Yi , Qu Zhao-Lei , Liu Bing , Ma Yang , Xu Jie , Shen Wen-Xiao , Sun Hui
Published: April 2021

Pine wilt disease (PWD), caused by pinewood nematode (PWN) Bursaphelenchus xylophilus, is globally one of the most destructive diseases of pine forests, especially in China. However, little is known about the effect of PWD on the host microbiome. In this study, the fungal community and functional structures in the needles, roots, and soil of and around Pinus thunbergii naturally infected by PWN were investigated by using high-throughput sequencing coupled with the functional prediction (FUNGuild). The results showed that fungal richness, diversity, and evenness in the needles of diseased trees were significantly lower than those of healthy ones (p < 0.05), whereas no differences were found in the roots and soil. Principal coordinate analysis (PCoA) showed that the fungal community and functional structures significantly differed only in the needles of diseased and healthy trees, but not in the soil and roots. Functionally, the saprotrophs had a higher abundance in the needles of diseased trees, whereas symbiotrophs abundance was higher in the needles of healthy trees (linear discriminant analysis (LDA) > 2.0, p < 0.05). These results indicated that PWN infection primarily affected the fungal community and functional structures in the needles of P. thunbergii, but not the roots and soil.
Pentacyclic Triterpenoids with Nitrogen-Containing Heterocyclic Moiety, Privileged Hybrids in Anticancer Drug Discovery
Authors: Khwaza Vuyolwethu , Mlala Sithenkosi , Oyedeji Opeoluwa O. , Aderibigbe Blessing A.
Published: April 2021

Pentacyclic triterpenoids are well-known phytochemicals with various biological activities commonly found in plants as secondary metabolites. The wide range of biological activities exhibited by triterpenoids has made them the most valuable sources of pharmacological agents. A number of novel triterpenoid derivatives with many skeletal modifications have been developed. The most important modifications are the formation of analogues or derivatives with nitrogen-containing heterocyclic scaffolds. The derivatives with nitrogen-containing heterocyclic compounds are among the most promising candidate for the development of novel therapeutic drugs. About 75% of FDA-approved drugs are nitrogen-containing heterocyclic moieties. The unique properties of heterocyclic compounds have encouraged many researchers to develop new triterpenoid analogous with pharmacological activities. In this review, we discuss recent advances of nitrogen-containing heterocyclic triterpenoids as potential therapeutic agents. This comprehensive review will assist medicinal chemists to understand new strategies that can result in the development of compounds with potential therapeutic efficacy.
Three-Component Reactions of 3-Arylidene-3H-Indolium Salts, Isocyanides and Amines
Authors: Nguyen Hung M. , Golantsov Nikita E. , Golubenkova Alexandra S. , Rybakov Victor B. , Voskressensky Leonid G.
Published: April 2021

A multicomponent reaction of isocyanides with aryl(indol-3-yl)methylium salts and amines has been found. A series of aryl(indol-3-yl)acetimidamides was obtained in up to 96% yields. In the case of ethyl isocyanoacetate, the reaction is followed by cyclization to form 3,5-dihydro-4H-imidazol-4-one derivatives.
Hydrogen Sulfide: Novel Endogenous and Exogenous Modulator of Oxidative Stress in Retinal Degeneration Diseases
Authors: Li Panpan , Liu Hanhan , Shi Xin , Prokosch Verena
Published: April 2021

Oxidative stress (OS) damage can cause significant injury to cells, which is related to the occurrence and development of many diseases. This pathological process is considered to be the first step to trigger the death of outer retinal neurons, which is related to the pathology of retinal degenerative diseases. Hydrogen sulfide (H2S) has recently received widespread attention as a physiological signal molecule and gas neuromodulator and plays an important role in regulating OS in eyes. In this article, we reviewed the OS responses and regulatory mechanisms of H2S and its donors as endogenous and exogenous regulators in retinal degenerative diseases. Understanding the relevant mechanisms will help to identify the therapeutic potential of H2S in retinal degenerative diseases.
Monte Carlo Simulation and Experimental Studies of CO2, CH4 and Their Mixture Capture in Porous Carbons
Authors: Kohmuean Pakamas , Inthomya Worapoj , Wongkoblap Atichat , Tangsathitkulchai Chaiyot
Published: April 2021

Adsorption of carbon dioxide and methane in porous activated carbon and carbon nanotube was studied experimentally and by Grand Canonical Monte Carlo (GCMC) simulation. A gravimetric analyzer was used to obtain the experimental data, while in the simulation we used graphitic slit pores of various pore size to model activated carbon and a bundle of graphitic cylinders arranged hexagonally to model carbon nanotube. Carbon dioxide was modeled as a 3-center-Lennard-Jones (LJ) molecule with three fixed partial charges, while methane was modeled as a single LJ molecule. We have shown that the behavior of adsorption for both activated carbon and carbon nanotube is sensitive to pore width and the crossing of isotherms is observed because of the molecular packing, which favors commensurate packing for some pore sizes. Using the adsorption data of pure methane or carbon dioxide on activated carbon, we derived its pore size distribution (PSD), which was found to be in good agreement with the PSD obtained from the analysis of nitrogen adsorption data at 77 K. This derived PSD was used to describe isotherms at other temperatures as well as isotherms of mixture of carbon dioxide and methane in activated carbon and carbon nanotube at 273 and 300 K. Good agreement between the computed and experimental isotherm data was observed, thus justifying the use of a simple adsorption model.
Graphene Assisted in the Analysis of Coumarins in Angelicae Pubescentis Radix by Dispersive Liquid–Liquid Microextraction Combined with 1H-qNMR
Authors: Feng Yanmei , Li Qian , Qiu Daiyu , Li Guichen
Published: April 2021

The content of active components in traditional Chinese medicine is relatively small, and it is difficult to detect some trace components with modern analytical instruments, so good pretreatment and extraction are very important in the experiment. Graphene was introduced by a dispersive liquid–liquid microextraction method based on solidification of floating organic drop (DLLME-SFO) with graphene/1-dodecyl alcohol used as the extractant, and this method, combined with quantitative proton nuclear magnetic resonance spectroscopy (1H-qNMR), was used to simultaneously qualitative and quantitative osthole, columbianadin and isoimperatorin in Angelicae Pubescentis Radix. In this experiment, a magnetic stirrer was used for extraction, all NMR spectra were recorded on a Bruker Advance III 600 MHz spectrometer with dimethyl sulfoxide-d6 (DMSO-d6) as deuterated solvent and pyrazine as the internal standard. The influencing factors and NMR parameters in the extraction process were investigated and optimized. In addition, the methodology of the established method was also examined. The quantitative signals of osthole, columbianadin and isoimperatorin were at a chemical shift of δ6.25–δ6.26 ppm, δ6.83–δ6.85 ppm, and δ6.31–δ6.32 ppm. The linear ranges of osthole, columbianadin and isoimperatorin were all 0.0455–2.2727 mg/mL, and R2 were 0.9994, 0.9994 and 0.9995, respectively. The limits of detection of osthole, columbianadin and isoimperatorin were 0.0660, 0.0720, 0.0620 mg, and the limits of quantification of osthole, columbianadin and isoimperatorin were 0.2201, 0.2401, 0.2066 mg/mL. The solution had good stability and repeatability within 24 h. The recoveries of osthole, columbianadin and isoimperatorin were 102.26%, 99.89%, 103.28%, respectively. The established method is simple and easy to operate, which greatly reduces the cumbersome pretreatment of samples and has high extraction efficiency.
Antioxidant and Antidiabetic Activity of Proanthocyanidins from Fagopyrum dibotrys
Authors: Li Xin , Liu Jingling , Chang Qinxiang , Zhou Ziyun , Han Ruilian , Liang Zongsuo
Published: April 2021

Proanthocyanidins are natural glycosidase inhibitors with excellent antioxidant activity. This study aims to search for a new source of proanthocyanidins for the prevention and treatment of type 2 diabetes with higher content and better activity and get their structure elucidated. First, the total proanthocyanidins contents (TOPCs), antioxidant activity, antidiabetic activity of seven common Polygonaceae plants were analyzed and compared. Then proanthocyanidins from the rhizome of Fagopyrum dibotrys were purified, and the detailed structure was comprehensively analyzed by ultraviolet visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), 13C nuclear magnetic resonance spectroscopy (13C NMR), reversed-phase high-performance liquid chromatography-electrospray mass spectrometry (RP-HPLC-ESI-MS), and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The rhizome of F. dibotrys showed the highest TOPCs, the strongest antioxidant, and antidiabetic activities; the TOPCs, antioxidant and antidiabetic activities were all very significantly positively correlated. Proanthocyanidins purified from the rhizome of F. dibotrys showed better antidiabetic activity than grape seed proanthocyanidins (GsPs). Seventy-two proanthocyanidins from trimer to undecamer with a mean degree of polymerization (mDP) of about 5.02 ± 0.21 were identified with catechin and epicatechin as the dominant monomers. Conclusion: Proanthocyanidins are the main antioxidant and antidiabetic active substances of F. dibotrys and are expected to be developed into potential antioxidant and hypoglycemic products.
Synthesis and Chemical and Biological Evaluation of a Glycine Tripeptide Chelate of Magnesium
Authors: Case Derek R. , Zubieta Jon , Gonzalez Ren , Doyle Robert P.
Published: April 2021

Magnesium (Mg2+) plays a crucial role in over 80% of all metabolic functions. It is becoming increasingly apparent that magnesium deficiency (hypomagnesemia) may play an important role in chronic disease. To counteract magnesium deficiency, there is an unmet clinical need to develop new fully characterized, highly bioavailable, and substantially water-soluble magnesium supplements. To this end, triglycine (HG3), a tripeptide of the amino acid glycine, was chosen as a chelating ligand for magnesium, given its natural occurrence and water solubility, and entropically-driven metal binding. Herein, we discuss the synthesis, chemical and physical characterization, and cellular uptake of a magnesium triglycine chelate (MgG3), an octahedral complex with extraordinary water solubility and improved cellular uptake in CaCo-2 cells than select commonly used magnesium supplements.
Garcinielliptone G from Garcinia subelliptica Induces Apoptosis in Acute Leukemia Cells
Authors: Yun YoungSook , Shioura Mariko , Hitotsuyanagi Yukio , Yotsumoto Satoshi , Takahashi Yuji , Aoyagi Yutaka , Kinoshita Takeshi , Takeya Koichi , Inoue Hideshi
Published: April 2021

Cytotoxicity and apoptosis-inducing properties of compounds isolated from Garcinia subelliptica leaves were investigated. The hexane-soluble portion of MeOH extracts of G. subelliptica leaves that showed cytotoxic activity was separated to yield seven compounds 1–7. Chemical structure analysis using NMR spectroscopy and mass spectrometry confirmed that compound 1 was canophyllol, and compounds 2–7 were garcinielliptones N, O, J, G, F, and garcinielliptin oxide, respectively. Among them, garcinielliptone G (5) showed growth inhibition by causing apoptosis in THP-1 and Jurkat cells derived from human acute monocytic leukemia and T lymphocyte cells, respectively. Apoptosis induced by garcinielliptone G (5) was demonstrated by the detection of early apoptotic cells with fluorescein-labeled Annexin V and increases in cleaved caspase-3 and cleaved PARP protein levels. However, the addition of caspase inhibitor Z-VAD-FMK did not affect growth arrest or apoptosis induction. These results suggest that garcinielliptone G (5) can induce both caspase-3 activation and caspase-independent apoptosis. Therefore, garcinielliptone G (5) may be a potential candidate for acute leukemia treatment.
Lipidic Matrixes Containing Clove Essential Oil: Biological Activity, Microstructural and Textural Studies
Authors: Rojas John , Cabrera Sergio , Benavides Julie , Lopera Yasmín , Yarce Cristhian J.
Published: April 2021

Clove essential oil (CEO) is known for having excellent antioxidant and antimicrobial properties, but the poor stability of its components to light and temperature compromise this activity. The aim of this study is to evaluate the textural, antioxidant, antimicrobial and microstructural properties of matrixes produced with representative natural waxes and CEO. Thus, waxy emulsifiers, such as beeswax, candelilla wax, carnauba wax, and ozokerite wax, were employed to create such matrixes. The thermal, microstructural, textural, wetting, antioxidant, antimicrobial and infrared characteristics of the matrixes were then studied. The diverse chemical composition (long-chain wax esters in carnauba wax and short-chain fatty acids and hydrocarbons in beeswax and ozokerite wax, respectively) explained the differences in wetting, texture, melting, and crystallization characteristics. Crystal forms of these matrix systems varied from grainy, oval, to needle-like shape, but keeping an orthorhombic allomorph. The alignment and reorganization of beeswax and ozokerite wax into needle-like crystals increased the matrix strength and adhesion force compared to those of carnauba and candelilla matrixes, which showed weak strength and grainy morphology. The former two waxes and their matrixes also showed the largest plasticity. These lipidic matrixes show potential use for topical applications having acceptable antioxidant and textural properties.
“Texas-Sized” Molecular Boxes: From Chemistry to Applications
Authors: Chi Xiaodong , Tian Jinya , Luo Dan , Gong Han-Yuan , Huang Feihe , Sessler Jonathan L.
Published: April 2021

The design and synthesis of novel macrocyclic host molecules continues to attract attention because such species play important roles in supramolecular chemistry. However, the discovery of new classes of macrocycles presents a considerable challenge due to the need to embody by design effective molecular recognition features, as well as ideally the development of synthetic routes that permit further functionalization. In 2010, we reported a new class of macrocyclic hosts: a set of tetracationic imidazolium macrocycles, which we termed “Texas-sized” molecular boxes (TxSBs) in homage to Stoddart’s classic “blue box” (CBPQT4+). Compared with the rigid blue box, the first generation TxSB displayed considerably greater conformational flexibility and a relatively large central cavity, making it a good host for a variety of electron-rich guests. In this review, we provide a comprehensive summary of TxSB chemistry, detailing our recent progress in the area of anion-responsive supramolecular self-assembly and applications of the underlying chemistry to water purification, information storage, and controlled drug release. Our objective is to provide not only a review of the fundamental findings, but also to outline future research directions where TxSBs and their constructs may have a role to play.
Coumarin-Chalcone Hybrids as Inhibitors of MAO-B: Biological Activity and In Silico Studies
Authors: Moya-Alvarado Guillermo , Yañez Osvaldo , Morales Nicole , González-González Angélica , Areche Carlos , Núñez Marco Tulio , Fierro Angélica , García-Beltrán Olimpo
Published: April 2021

Fourteen coumarin-derived compounds modified at the C3 carbon of coumarin with an α,β-unsaturated ketone were synthesized. These compounds may be designated as chalcocoumarins (3-cinnamoyl-2H-chromen-2-ones). Both chalcones and coumarins are recognized scaffolds in medicinal chemistry, showing diverse biological and pharmacological properties among which neuroprotective activities and multiple enzyme inhibition, including mitochondrial enzyme systems, stand out. The evaluation of monoamine oxidase B (MAO-B) inhibitors has aroused considerable interest as therapeutic agents for neurodegenerative diseases such as Parkinson’s. Of the fourteen chalcocumarins evaluated here against MAO-B, ChC4 showed the strongest activity in vitro, with IC50 = 0.76 ± 0.08 µM. Computational docking, molecular dynamics and MM/GBSA studies, confirm that ChC4 binds very stably to the active rMAO-B site, explaining the experimental inhibition data.
Screening a Strain of Klebsiella sp. O852 and the Optimization of Fermentation Conditions for Trans-Dihydrocarvone Production
Authors: Chen Li , Zhang Lu-Lu , Ren Jing-Nan , Li Xiao , Fan Gang , Pan Si-Yi
Published: April 2021

Flavors and fragrances have high commercial value in the food, cosmetic, chemical and pharmaceutical industries. It is interesting to investigate the isolation and characterization of new microorganisms with the ability to produce flavor compounds. In this study, a new strain of Klebsiella sp. O852 (accession number CCTCC M2020509) was isolated from decayed navel orange (Citrus sinensis (L.) Osbeck), which was proved to be capable of converting limonene to trans-dihydrocarvone. Besides, the optimization of various reaction parameters to enhance the trans-dihydrocarvone production in shake flask was performed for Klebsiella sp. O852. The results showed that the yield of trans-dihydrocarvone reached up to 1 058 mg/L when Klebsiella sp. O852 was incubated using LB-M medium for 4 h at 36 °C and 150 rpm, and the biotransformation process was monitored for 36 h after adding 1680 mg/L limonene/ethanol (final ethanol concentration of 0.8% (v/v)). The content of trans-dihydrocarvone increased 16 times after optimization. This study provided a basis and reference for producing trans-dihydrocarvone by biotransformation.
In Vitro Antimicrobial, Antioxidant and Anticancer Activities of Egyptian Citrus Beebread
Authors: Elsayed Nesren , El-Din Hatem Sharaf , Altemimi Ammar B. , Ahmed Hanaa Y. , Pratap-Singh Anubhav , Abedelmaksoud Tarek Gamal
Published: April 2021

In this study, Egyptian beebread (EBB) was investigated for its nutritive value, chemical composition, antioxidant properties, antimicrobial and antitumor activities. Results indicated that EBB was a good source of protein (23.58 ± 0.183 g/100 g BB), total free sugar (20.266 ± 0.930) and potassium (290.202 ± 2.645 mg/100 g). Additionally, 14 fatty acids were identified in EBB, wherein polyunsaturated and monounsaturated fatty acids represented 51.06% ± 0.09% and 9.86% ± 0.01%, respectively. The EBB extract exhibited almost 400% better antiradical activity than BHT, with IC50 of EBB extract being 10.7 µg/mL compared to 39.5 µg/mL for BHT. EBB exhibited higher inhibitory activity than the reference compound against Staphylococcus aureus and Escherichia coli, followed by Bacillus subtilis. No inhibitory activity was observed against Aspergillus Niger. Additionally, the highest inhibitory activity was recorded against Caco-2 cells, followed by PC3 and HepG-2 cancer cell lines with IC50 values 262, 314 and 386 μg/mL, respectively. These findings establish the potential of EBB as an antioxidant, antimicrobial and antitumor agent, with possible applications as natural food supplements and natural preservatives.
Redox Speciation of Vanadium in Estuarine Waters Using Improved Methodology Based on Anion Exchange Chromatography Coupled to HR ICP-MS System
Authors: Knežević Lucija , Omanović Dario , Bačić Niko , Mandić Jelena , Bura-Nakić Elvira
Published: April 2021

An improved methodology was developed for V redox speciation in estuarine waters using a hyphenated technique consisting of ion chromatograph (IC) with an anion exchange column and a high-resolution inductively coupled plasma mass spectrometer (HR ICP-MS). This approach enables the direct determination of V(V), whereas reduced species (mainly V(IV)) are calculated by subtracting V(V) concentrations from the measured total V concentration. Based on the “on-column” V(V) chelation mechanism by EDTA, with the eluent composed of 40 mmol L−1 ammonium bicarbonate, 40 mmol L−1 ammonium sulphate, 8 mmol L−1 ethylenediaminetetraacetic acid and 3% acetonitrile, the method was successfully used for analyses of V redox speciation in samples taken in the vertical salinity gradient of the highly stratified Krka River estuary. Due to the matrix effects causing different sensitivities, a standard addition method was used for V(V) quantification purposes. The limit of detection (LOD) was also found to be matrix related: 101.68 ng L−1 in the seawater and 30.56 µg L−1 in the freshwater. Performed stability tests showed that V redox speciation is preserved at least 7 days in un-treated samples, possibly due to the stabilization of V-reduced species with natural organic matter (NOM). The dominant V form in the analysed samples was V(V) with the reduced V(IV) accounting for up to 26% of the total dissolved pool. The concentration of V(IV) was found to correlate negatively with the oxygen concentration. Significant removal of dissolved V was detected in oxygen depleted zones possibly related to the particle scavenging.
Preparation and Characterization of Biobased Lignin-Co-Polyester/Amide Thermoplastics
Authors: Young Eric L. , McDonald Armando G.
Published: April 2021

More than 23 million tonnes of lignin are produced annually in the US from wood pulping and 98% of this lignin is burnt. Therefore, creating products from lignin, such as plastics, offers an approach for obtaining sustainable materials in a circular economy. Lignin-based copolymers were synthesized using a single pot, solvent free, melt condensation reaction. The synthesis occurred in two stages. In the first stage, a biobased prepolymer consisting of butanediol (BD, 0.8–1 molar content) and a diacid (succinic (SA), adipic (AA) and suberic acids (SuA), with varying amounts of diaminobutane (DAB, 0–0.2 molar content) was heated under vacuum and monitored by Fourier transform infra-red (FTIR) spectroscopy and electrospray ionization-mass spectrometry (ESI-MS). In the second stage, prepolymer was mixed with a softwood kraft lignin (0–50 wt.%) and further reacted under vacuum at elevated temperature. Progression of the polymerization reaction was monitored using FTIR spectroscopy. The lignin-copolyester/amide properties were characterized using tensile testing, X-ray diffraction (XRD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Lignin co-polymer tensile (strength 0.1–2.1 MPa and modulus 2 to 338 MPa) properties were found to be influenced by the diacid chain length, lignin, and DAB contents. The lignin-copolymers were shown to be semi-crystalline polymer and have thermoplastic behavior. The SA based copolyesters/amides were relatively stiff and brittle materials while the AA based copolyesters/amides were flexible and the SuA based copolyesters/amides fell in-between. Additionally, > 30 wt.% lignin the lignin- copolyesters/amides did not exhibit melt behavior. Lignin-co-polyester/amides can be generated using green synthesis methods from biobased building blocks. The lignin- copolyesters/amides properties could be tuned based on the lignin content, DAB content and diacid chain length. This approach shows that undervalued lignin can be used in as a macromonomer in producing thermoplastic materials.
Polyphenols and Fish Oils for Improving Metabolic Health: A Revision of the Recent Evidence for Their Combined Nutraceutical Effects
Authors: Méndez Lucía , Medina Isabel
Published: April 2021

Polyphenols and omega-3 polyunsaturated fatty acids from fish oils, i.e., eicosapentaenoic and docosahexaenoic acids, are well-recognized nutraceuticals, and their single antioxidant and anti-inflammatory properties have been demonstrated in several studies found in the literature. It has been reported that the combination of these nutraceuticals can lead to three-fold increases in glutathione peroxidase activity, two-fold increases in plasma antioxidant capacity, decreases of 50–100% in lipid peroxidation, protein carbonylation, and urinary 8-isoprotanes, as well as 50–200% attenuation of common inflammation biomarkers, among other effects, as compared to their individual capacities. Therefore, the adequate combination of those bioactive food compounds and their single properties should offer a powerful tool for the design of successfully nutritional interventions for the prevention and palliation of a plethora of human metabolic diseases, frequently diet-induced, whose etiology and progression are characterized by redox homeostasis disturbances and a low-grade of chronic inflammation. However, the certain mechanisms behind their biological activities, in vivo interaction (both between them and other food compounds), and their optimal doses and consumption are not well-known yet. Therefore, we review here the recent evidence accumulated during the last decade about the cooperative action between polyphenols and fish oils against diet-related metabolic alterations, focusing on the mechanisms and pathways described and the effects reported. The final objective is to provide useful information for strategies for personalized nutrition based on these nutraceuticals.
Antiradical Activity of Beetroot (Beta vulgaris L.) Betalains
Authors: Spiegel Maciej , Gamian Andrzej , Sroka Zbigniew
Published: April 2021

Flavonoids, phenolic acids, and anthocyanidins are widely studied polyphenolics owing to their antiradical activity. Recently, beetroot dyes have drawn an attention as possible radical scavengers, but scant information can be found on this topic. In this study selected compounds were investigated using computational chemistry methods. Implicit water at physiological pH was chosen as the environment of interest. Betalains’ dissociation process and electronic structure were examined, as well as the reactivity in six pathways against some common radicals, such as hydroxyl, hydroperoxide, superoxide, and nitric oxide. The study showed that all carboxyl groups are dissociated in the given conditions. The dissociation process impacts the electronic structure, which has consequences for the overall activity. Highly stabilized conjugated structures favor the electron–accepting type of scavenging reactions, primarily by a radical adduct formation mechanism. Betanidin and indicaxanthin were found to be the most promising of the compounds studied. Nevertheless, the study established the role of betalains as powerful antiradical dietary agents.
Solvent-Impregnated Resins Based on the Mixture of (2-Diphenylphosphoryl)-4-ethylphenoxy)methyl) diphenylphosphine Oxide and Ionic Liquid for Nd(III) Recovery from Nitric Acid Media
Authors: Kovalenko Olga , Baulin Vladimir , Baulin Dmitriy , Tsivadze Aslan
Published: April 2021

Novel solvent-impregnated resins (SIRs) were prepared by treatment of styrene–divinylbenzene copolymer (LPS-500) with mixtures of the promising polydentante extractant (2-diphenylphosphoryl)-4-ethylphenoxy)methyl)diphenylphosphine oxide (L) and an ionic liquid [C4mim]+[Tf2N]−for the extraction chromatography recovery of Nd(III) from nitric acid solutions. It was shown that introduction of the ionic liquid into the SIR composition results in considerable enhancement of the Nd(III) recovery efficiency compared with resin impregnated only by L in slightly acidic media. The influence of the L: ionic liquid molar ratio in the SIRs composition, their percentages, concentration of metal and HNO3 in the eluent, and acid type on the value of synergistic effect and adsorption efficiency of Nd(III) recovery was studied. The SIR containing 40% of mixture of L and [C4mim]+[Tf2N]− with molar ratio 2:1 turned out to be the most efficient. The selectivity of Nd(III) separation from light and heavy rare-earth elements was studied and the optimal conditions of Nd(III) adsorption recovery and stripping by this SIR were chosen. It was found that in recovery efficiency of Nd(III) developed SIR exceeded the SIR containing Cyanex 923 (a mixture of monodentate trialkylphosphine oxides) and [C4mim]+[Tf2N]−.
Spectral Features of Canthaxanthin in HCP2. A QM/MM Approach
Authors: Clark Kevin , Pigni Natalia B. , Wijesiri Kithmini , Gascón José A.
Published: April 2021

The increased interest in sequencing cyanobacterial genomes has allowed the identification of new homologs to both the N-terminal domain (NTD) and C-terminal domain (CTD) of the Orange Carotenoid Protein (OCP). The N-terminal domain homologs are known as Helical Carotenoid Proteins (HCPs). Although some of these paralogs have been reported to act as singlet oxygen quenchers, their distinct functional roles remain unclear. One of these paralogs (HCP2) exclusively binds canthaxanthin (CAN) and its crystal structure has been recently characterized. Its absorption spectrum is significantly red-shifted, in comparison to the protein in solution, due to a dimerization where the two carotenoids are closely placed, favoring an electronic coupling interaction. Both the crystal and solution spectra are red-shifted by more than 50 nm when compared to canthaxanthin in solution. Using molecular dynamics (MD) and quantum mechanical/molecular mechanical (QM/MM) studies of HCP2, we aim to simulate these shifts as well as obtain insight into the environmental and coupling effects of carotenoid–protein interactions.
Exploratory Study Using Urinary Volatile Organic Compounds for the Detection of Hepatocellular Carcinoma
Authors: Bannaga Ayman S. , Tyagi Heena , Daulton Emma , Covington James A. , Arasaradnam Ramesh P.
Published: April 2021

Hepatocellular carcinoma (HCC) biomarkers are lacking in clinical practice. We therefore explored the pattern and composition of urinary volatile organic compounds (VOCs) in HCC patients. This was done in order to assess the feasibility of a potential non-invasive test for HCC, and to enhance our understanding of the disease. This pilot study recruited 58 participants, of whom 20 were HCC cases and 38 were non-HCC cases. The non-HCC cases included healthy individuals and patients with various stages of non-alcoholic fatty liver disease (NAFLD), including those with and without fibrosis. Urine was analysed using gas chromatography–ion mobility spectrometry (GC–IMS) and gas chromatography–time-of-flight mass spectrometry (GC–TOF-MS). GC–IMS was able to separate HCC from fibrotic cases with an area under the curve (AUC) of 0.97 (0.91–1.00), and from non-fibrotic cases with an AUC of 0.62 (0.48–0.76). For GC-TOF-MS, a subset of samples was analysed in which seven chemicals were identified and tentatively linked with HCC. These include 4-methyl-2,4-bis(p-hydroxyphenyl)pent-1-ene (2TMS derivative), 2-butanone, 2-hexanone, benzene, 1-ethyl-2-methyl-, 3-butene-1,2-diol, 1-(2-furanyl)-, bicyclo(4.1.0)heptane, 3,7,7-trimethyl-, [1S-(1a,3β,6a)]-, and sulpiride. Urinary VOC analysis using both GC–IMS and GC-TOF-MS proved to be a feasible method of identifying HCC cases, and was also able to enhance our understanding of HCC pathogenesis.
Facial Swelling in the Presence of a COVID-19 Diagnosis: Case Report
Authors: Fleagle Jenelle , Lorch Margarita
Published: April 2021

COVID-19 became a pandemic with a worldwide impact leading to stay-at-home orders, death, economic difficulties, and a significant influence on daily lives. Dental services became limited at this time, causing increased concerns for patients requiring urgent dental care. We report the case of a 5-year-old previously healthy male who presented to our hospital’s emergency department (ED) with facial swelling secondary to infected maxillary left molars. Extractions were performed in the ED with moderate sedation. He was later found to be COVID-19 positive before admission for intravenous antibiotics. The use of universal precautions during the pandemic in treating patients with possible COVID-19 symptoms and in aerosol-generating procedures is recommended. Evaluating and providing treatment to our patients with urgent dental care should not be delayed to prevent further complications and decrease the burden placed on the ED, which may be limited in its ability to provide definitive care.
Techniques for Reconstruction of Strange Objects at MPD
Authors: Zinchenko Alexander
Published: April 2021

Study of the strangeness production in heavy-ion collisions is one of the most important parts of the physics program of the MPD experiment at the NICA collider. Therefore, the problem of a reliable and efficient reconstruction of strange objects should be addressed with a high priority during the preparation to the experiment. The paper describes the approach to this task which was developed and implemented as a part of the MPD software. Some results of its application during the detector Monte Carlo feasibility studies are presented.
Study on a Novel Filter Media Incorporating with Core Shell Nanoencapsulated Phase Change Material: Fabrication and Evaluation
Authors: Zhang Chi , Chang Shuo , Song Gaoju , Liu Jianlin , Shen Henggen
Published: April 2021

Thermal performance of filter media plays a significant effect on the filtration efficiency of baghouse, especially its tolerance of high temperature air and chemical erosion. In this study, nano-encapsulated phase change material within the silica shell (NPCMs) is synthesized through a self-assembly method based on polymer—hyperbranched precursor polyethoxysiloxane (PEOS). Filter media is fabricated by NPCMs through a facile dip-dry-cure process to enhance its thermal regulation and serving durability. Filter media acts as frame-supporting of the functional structure NPCMs. Incorporating NPCMs into filter media optimizes the microstructure and filtration efficiency of baghouse. The penetration rate was reduced from 457 × 10−4% of the control filter media to 5 × 10−4%. Meanwhile, the novel filter media lowers the temperature up to 20 °C than the surroundings. The novel filter media exhibits not only better mechanical properties, but also much less tensile strength loss after suffering 100 thermal shock cycles with simultaneous chemical exposure, from 37.58% to 20.37%. Overall, the filter media incorporated with NPCMs demonstrates excellent performances on filter efficiency, thermal regulation, and environmental endurance, which has the potential for extending lifespans and enhancing operation stability of filter bags in industrial air pollutant control.