Feature Papers in AppliedChem

A special issue of AppliedChem (ISSN 2673-9623).

Deadline for manuscript submissions: closed (31 August 2023) | Viewed by 59085

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This is a collection of top-quality papers published in open access form by editorial board members, or those invited by the editorial office and the Editor-in-Chief. The papers should be long research papers (or review papers) with full and detailed summary of the author’s own work carried out so far.

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Published Papers (25 papers)

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17 pages, 3978 KiB  
Article
Tetrahydroisoquinoline-Triazole Derivatives: Novel Nicotinamide N-Methyltransferase Inhibitors
by Alison T. Ung and Matthew Payne
AppliedChem 2023, 3(4), 509-525; https://doi.org/10.3390/appliedchem3040032 - 21 Nov 2023
Viewed by 950
Abstract
Through the Lilly Open Innovation Drug Discovery program (OIDD), we discovered five cationic bis(aryltriazol-4-yl)methyl)-6,7-dimethoxytetrahydroisoquinolinium derivatives that effectively inhibit human nicotinamide N-methyltransferase. Compounds 4a, 4c, and 4f demonstrated activity against hNNMT in enzymatic-based testing, with IC50 values of 3.177 μM, 7.9 μM, [...] Read more.
Through the Lilly Open Innovation Drug Discovery program (OIDD), we discovered five cationic bis(aryltriazol-4-yl)methyl)-6,7-dimethoxytetrahydroisoquinolinium derivatives that effectively inhibit human nicotinamide N-methyltransferase. Compounds 4a, 4c, and 4f demonstrated activity against hNNMT in enzymatic-based testing, with IC50 values of 3.177 μM, 7.9 μM, and 4.477 μM, respectively. In cell-based testing, 4c and 4f inhibited the enzyme in HEK293 cells with an IC50 value of 2.81 μM and 1.97 μM. Compound 4m inhibited hNNMT in the enzymatic-based assay by 98% at a concentration of 10 μM, with IC50 of 1.011 μM in the cell-based assay. Through structure-activity relationship analysis, we found that the active compounds had electron-withdrawing substituents at the 4-position of the phenyl-triazole, while compounds containing bulky and electron-donating groups at the same position did not display any activity. The results of docking studies using AutoDock 4.2 showed that all active compounds had similar binding patterns at the NNMT active site. They occupied the nicotinamide binding site and about two-thirds of the S-adenosyl-L-methionine site. However, the SAR and docking results of 4g contradicted the compound’s inactivity. Nevertheless, the molecular docking studies provided insight into how the ligands interact with the protein and explained the activity of our compounds. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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15 pages, 15207 KiB  
Article
Evaluation of the Effects of Nano-SiO2 Microemulsion on Decompression and Augmented Injection in the Eunan Tight Reservoir
by Ke Wu, Mingbiao Xu, Shoucheng Wen and Xuefeng Deng
AppliedChem 2023, 3(4), 477-491; https://doi.org/10.3390/appliedchem3040030 - 25 Oct 2023
Viewed by 655
Abstract
The residual oil saturation of the matrix near the well zone of a tight reservoir is high due to the tight reservoir’s complex conditions, such as the small pore throat radius and low permeability of the matrix and the development of microfractures, which [...] Read more.
The residual oil saturation of the matrix near the well zone of a tight reservoir is high due to the tight reservoir’s complex conditions, such as the small pore throat radius and low permeability of the matrix and the development of microfractures, which can result in serious water channeling, even after long-term water injection development. The aim of this paper is to improve the effects of depressurization and augmented injection for tight reservoir waterflooding development by reducing the tight matrix’s residual oil saturation, increasing and maintaining its water phase permeability near the well zone using a nano-SiO2 microemulsion system with a small particle size and high interfacial activity. Therefore, four nano-microemulsion systems were evaluated and screened for their temperature resistance, salt resistance, interfacial tension, solubilization, and dilution resistance. A microemulsion system of 13% A + 4% B + 4% C + 4% n-butanol + 6% oil phase + 69% NaCl solution (10%) + 1% OP-5 + 0.5% anti-temperature agent + 0.3% nanosilica material was preferred. According to the core displacement experiment, the depressurization rate can reach 28~60% when the injection concentration of the system is 1~10% and the injection volume is 2~5 PV. The results of the on-site test show that the water injection pressure dropped to 17.5 MPa, which was lower than the reservoir fracture re-opening pressure. The pressure reduction rate was approximately 20%. The validity period of the depressurization and augmented injection has reached 23 months to date. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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9 pages, 1320 KiB  
Article
The Ability of Near-Infrared Spectroscopy to Discriminate Plant Protein Mixtures: A Preliminary Study
by Buddhi Dayananda, Priyam Chahwala and Daniel Cozzolino
AppliedChem 2023, 3(3), 428-436; https://doi.org/10.3390/appliedchem3030027 - 01 Sep 2023
Cited by 1 | Viewed by 938
Abstract
The aim of this paper was to evaluate the effect of two different matrices (e.g., starch base flour vs. protein base flour) on the ability of near-infrared (NIR) spectroscopy to classify binary mixtures of chickpea (protein), corn and tapioca (starch) flours. Binary mixtures [...] Read more.
The aim of this paper was to evaluate the effect of two different matrices (e.g., starch base flour vs. protein base flour) on the ability of near-infrared (NIR) spectroscopy to classify binary mixtures of chickpea (protein), corn and tapioca (starch) flours. Binary mixtures were made by mixing different proportions of chickpea plus corn, chickpea plus tapioca, and corn plus tapioca flour. Spectra were collected using NIR spectroscopy and the data analyzed using techniques such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The results showed an effect of the matrix on the PLS-DA classification results, in both classification rates and PLS loadings. The different combinations of flours/mixtures showed changes in absorbance values around 4752 cm−1 that are associated with starch and protein. Nevertheless, the use of NIR spectroscopic might provide a valuable initial screening and identification of the potential contamination of flours along the supply and value chains, enabling more costly methods to be used more productively on suspect samples. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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17 pages, 8199 KiB  
Article
Vapor Composition and Vaporization Thermodynamics of 1-Ethyl-3-methylimidazolium Hexafluorophosphate Ionic Liquid
by Anatoliy M. Dunaev, Vladimir B. Motalov, Mikhail A. Korobov, Dmitrii Govorov, Victor V. Aleksandriiskii and Lev S. Kudin
AppliedChem 2023, 3(2), 303-319; https://doi.org/10.3390/appliedchem3020019 - 02 Jun 2023
Viewed by 1201
Abstract
The processes of the sublimation and thermal decomposition of the 1-ethyl-3-methylimidazolium hexafluorophosphate ionic liquid (EMImPF6) were studied by a complex approach including Knudsen effusion mass spectrometry, IR and NMR spectroscopy, and quantum chemical calculations. It was established that the vapor over [...] Read more.
The processes of the sublimation and thermal decomposition of the 1-ethyl-3-methylimidazolium hexafluorophosphate ionic liquid (EMImPF6) were studied by a complex approach including Knudsen effusion mass spectrometry, IR and NMR spectroscopy, and quantum chemical calculations. It was established that the vapor over the liquid phase primarily consists of decomposition products under equilibrium conditions. Otherwise, the neutral ion pairs are the only vapor components under Langmuir conditions. To identify the nature of the decomposition products, an experiment on the distillation of the ionic liquid was performed and the collected distillate was analyzed. It was revealed by the IR and NMR spectroscopy that EMImPF6 decomposes to substituted imidazole-2-ylidene (C6N2H10PF5) and HF. The measured vapor pressure of C6N2H10PF5 reveals a very low activity of the decomposition products (<10−4) in the liquid phase. The absence of a significant accumulation of decomposition products in the condensed phase makes it possible to determine the enthalpy of sublimation of the ionic liquid assuming its unchanged activity. The thermodynamics of the EMImPF6 sublimation was studied by Knudsen effusion mass spectrometry. The formation enthalpy of EMImPF6 in the ideal gas state was found from a combination of the sublimation enthalpy and formation enthalpy of the ionic liquid in the condensed state. The obtained value is in good agreement with those calculated by quantum chemical methods. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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23 pages, 2568 KiB  
Article
Evaluation of Substituted N-Aryl Maleimide and Acrylamides for Bioconjugation
by Hugh G. Hiscocks, Giancarlo Pascali and Alison T. Ung
AppliedChem 2023, 3(2), 256-278; https://doi.org/10.3390/appliedchem3020016 - 15 May 2023
Viewed by 1799
Abstract
Novel SF5-bearing maleimide and acrylamide derivatives were synthesised as potential [18F]radio-prosthetic groups for radiolabelling peptides and proteins. The efficacy of selected prosthetic groups was first assessed through bioconjugation with protected model amino acid derivatives. These reactions were investigated on [...] Read more.
Novel SF5-bearing maleimide and acrylamide derivatives were synthesised as potential [18F]radio-prosthetic groups for radiolabelling peptides and proteins. The efficacy of selected prosthetic groups was first assessed through bioconjugation with protected model amino acid derivatives. These reactions were investigated on an analytical scale via LC-MS across a pH range to quantitatively evaluate this prosthetic group’s reactivity and stability. Model bioconjugate reactions were then replicated using analogous para-substituted derivatives to determine the influence of the electronic effects of -SF5. Finally, the SF5-bearing prosthetic groups were utilised for bioconjugation with cancer-targeting c-RGD peptides. N-aryl maleimides reacted extremely efficiently with the model amino acid N-acetyl-L-cysteine. The subsequent conjugates were obtained as regio-isomeric mixtures of the corresponding thio-succinamic acids in yields of 80–96%. Monitoring the bioconjugate reaction by LC-MS revealed that ring hydrolysis of the intermediate SF5–thio-succinimide conjugate occurred instantaneously, an advantageous quality in minimising undesirable thiol exchange reactions with non-targeted cysteine residues. In contrast, N-aryl acrylamides demonstrated poor solubility in semi-aqueous media (<1 mM). In turn, synthetic-scale model bioconjugations with Nα-acetyl-L-lysine were performed in methanol, affording the corresponding acrylamide conjugates in modest to high yield (58–89%). Including electron-deficient, fluorinated prosthetic groups for bioconjugation will broaden their applicability within the fields of 19F-MRI and PET imaging. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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27 pages, 2334 KiB  
Article
New Physicochemical Methodology for the Determination of the Surface Thermodynamic Properties of Solid Particles
by Tayssir Hamieh
AppliedChem 2023, 3(2), 229-255; https://doi.org/10.3390/appliedchem3020015 - 10 May 2023
Cited by 4 | Viewed by 1473
Abstract
The study of the surface thermodynamic properties of solid materials is primordial for the determination of the dispersive surface energy, polar enthalpy of adsorption and Lewis’s acid base properties of solid particles. The inverse gas chromatography technique (IGC) at infinite dilution is the [...] Read more.
The study of the surface thermodynamic properties of solid materials is primordial for the determination of the dispersive surface energy, polar enthalpy of adsorption and Lewis’s acid base properties of solid particles. The inverse gas chromatography technique (IGC) at infinite dilution is the best surface technique for the determination of the surface physicochemical properties of materials. (1) Background: This paper was devoted to studying the surface properties of solid materials, such as alumina, titania and silica particles, using the IGC technique. (2) Methods: Different methods and molecular models, such as the spherical, cylindrical, Van der Waals, Redlich–Kwong, Kiselev and geometric models, were used to determine the London dispersive surface energy of solid surfaces. The Hamieh model was also used and highlighted the thermal effect on the surface area of solvents. (3) Results: The variations of the dispersive surface energy and the free energy of adsorption were determined for solid particles as a function of the temperature, as well as their Lewis’s acid base constants. Alumina surfaces were proved to exhibit a strong Lewis amphoteric character three times more basic than acidic, titanium dioxide more strongly basic than acidic and silica surface exhibited the stronger acidity. (4) Conclusions: The new methodology, based on the Hamieh model, gave the more accurate results of the physicochemical properties of the particle surfaces. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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13 pages, 3166 KiB  
Article
Evaluation of an Ion-Associate Phase Formed In Situ from the Aqueous Phase by Adding Benzethonium Chloride and Sodium Ethylbenzenesulfonate for Microextraction
by Noriko Hata, Akane Igarashi, Rie Yasui, Maho Matsushita, Nozomi Kohama, Tomoka Komiyama, Kazuto Sazawa, Hideki Kuramitz and Shigeru Taguchi
AppliedChem 2023, 3(1), 32-44; https://doi.org/10.3390/appliedchem3010003 - 09 Jan 2023
Viewed by 1535
Abstract
The concentration region at which the solvent is formed during in situ solvent formation microextraction is determined by varying the concentrations of the two components required to form a solvent. In particular, a solvent is formed in situ during ion-associate phase (IAP) microextraction [...] Read more.
The concentration region at which the solvent is formed during in situ solvent formation microextraction is determined by varying the concentrations of the two components required to form a solvent. In particular, a solvent is formed in situ during ion-associate phase (IAP) microextraction by mixing an aqueous solution with an organic cation and an organic anion. In this study, benzethonium chloride (BenCl) and sodium ethylbenzenesulfonate (NaEBS) were employed as the organic cation and anion sources of model IAPs to thoroughly investigate the in situ solvent formation. Additionally, the formation of the IAPs and the solvent via centrifugation of the formed ion associates was examined. We demonstrated that ion associates are formed when the product of [EBS] and [Ben] is greater than the solubility product and [EBS] is greater than [Ben]. The highest extraction of polycyclic aromatic hydrocarbons (PAHs) was achieved with an amount of NaEBS 40 times greater than that of BenCl. A higher hydrophobicity in the IAP extraction of PAHs, estrogens, and pesticides facilitated extraction into the IAP. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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10 pages, 2018 KiB  
Article
E-Eye Solution for the Discrimination of Common and Niche Celery Ecotypes
by Alessandra Biancolillo, Martina Foschi and Angelo Antonio D’Archivio
AppliedChem 2023, 3(1), 1-10; https://doi.org/10.3390/appliedchem3010001 - 22 Dec 2022
Cited by 1 | Viewed by 1175
Abstract
Celery (Apium graveolens L.) is a well- known plant and at the basis of the culinary tradition of different populations. In Italy, several celery ecotypes, presenting unique peculiarities, are grown by small local producers, and they need to be characterized, in order [...] Read more.
Celery (Apium graveolens L.) is a well- known plant and at the basis of the culinary tradition of different populations. In Italy, several celery ecotypes, presenting unique peculiarities, are grown by small local producers, and they need to be characterized, in order to be protected and safeguarded. The present work aims at developing a fast and non-destructive method for the discrimination of a common celery (the "Elne" celery) from a typical celery of Abruzzo (Central Italy). The proposed strategy is based on the use of an e-eye tool which allows the collection of images used to infer colorgrams. Initially, a principal component analysis model was used to investigate the trends and outliers in the data. Then, the classification between the common celery (Elne class) and celery from Torricella Peligna (Torricella class) was achieved by a discriminant analysis, conducted by sequential preprocessing through orthogonalization (SPORT) and sequential and orthogonalized covariance selection (SO-CovSel) and by a class-modelling method called soft independent modelling of class analogies (SIMCAs). Among these, the highest accuracy was provided by the strategies, based on the discriminant classifiers, both of which provided a total accuracy of 82% in the external validation. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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12 pages, 2276 KiB  
Article
Geochemical Characterization of Nyamyumba Hot Springs, Northwest Rwanda
by Francois Hategekimana, Theophile Mugerwa, Cedrick Nsengiyumva, Fils Vainqueur Byiringiro and Digne Edmond Rwabuhungu Rwatangabo
AppliedChem 2022, 2(4), 247-258; https://doi.org/10.3390/appliedchem2040017 - 13 Dec 2022
Cited by 1 | Viewed by 1923
Abstract
A hot spring is a hot water source that naturally occurs on the surface of the Earth from underground; it is typically heated by subterranean volcanic activity and the local underground geothermal gradient. There are four main hot springs in Rwanda, such as: [...] Read more.
A hot spring is a hot water source that naturally occurs on the surface of the Earth from underground; it is typically heated by subterranean volcanic activity and the local underground geothermal gradient. There are four main hot springs in Rwanda, such as: Kalisimbi, Bugarama, Kinigi, and Nyamyumba, formerly named Gisenyi hot springs. It is often believed that soaking in a hot spring is a great way to naturally detox human skin. This research focuses on the geochemical analysis of Nyamyumba hot springs, located near the fresh water supply of Lake Kivu, with the purpose of understanding its healing capacity and safety. The Nyamyumba hot springs are located in the western branch of the East African Rift System, near the Virunga volcanic complex, which explains the rising and heating mechanism of the water. The concentrations of sulfate, iron, ammonia, silica, and phosphate, and the conductivity, alkalinity, and salinity of the water were measured using standard procedures. The results showed that the hot spring water has higher concentrations of chemicals compared to the Lake Kivu water, and the geochemistry of these hot springs may be associated with rock dissolution by hot water. The measured parameters were compared with World Health Organization (WHO) standards for recreational waters, and it has been identified that the Nyamyumba hot springs are safe to use for swimming and therapeutic activities. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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16 pages, 1022 KiB  
Article
Group Contribution Revisited: The Enthalpy of Formation of Organic Compounds with “Chemical Accuracy” Part III
by Robert J. Meier
AppliedChem 2022, 2(4), 213-228; https://doi.org/10.3390/appliedchem2040015 - 11 Nov 2022
Cited by 4 | Viewed by 2099
Abstract
Group contribution (GC) methods to predict thermochemical properties are eminently important to process design. We report on a GC parametrization for the heat of formation of organic molecules exhibiting chemical accuracy, i.e., a maximum 1 kcal/mol (4.2 kJ/mol) difference between experimental and model [...] Read more.
Group contribution (GC) methods to predict thermochemical properties are eminently important to process design. We report on a GC parametrization for the heat of formation of organic molecules exhibiting chemical accuracy, i.e., a maximum 1 kcal/mol (4.2 kJ/mol) difference between experimental and model values, whilst having a minimum number of parameters to avoid overfitting. We report an extension of recent findings to chloro-alkanes, fluoro-hydrocarbons, benzylhalides, nitro-alkanes, and acetals. Compared to the existing literature, we obtained a superior model exhibiting chemical accuracy, with exceptions when the inherent GC assumption on linearity and additivity is not valid. Moreover, to have a reliable method and not only a low absolute average deviation as reported in most publications, we accepted no or exceptionally few outliers. The example of the 1,3-dioxolane acetals revealed that by adopting the appropriate size of a group representing the acetal leads to a model showing good accuracy. The overall conclusion of the three papers on this topic is that it is feasible to achieve chemical accuracy when using high-quality experimental data and the judicious definition of chemical groups. Despite the GC method being old, the present work shows substantial and necessary increase in performance can still be achieved. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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14 pages, 1552 KiB  
Article
Laminaria hyperborea as a Source of Valuable Glyceroglycolipids—A Characterization of Galactosyldiacilglycerols in Stipe and Blade by HPLC-MS/MS
by Lena Foseid, Hanne Devle, Carl Fredrik Naess-Andresen and Dag Ekeberg
AppliedChem 2022, 2(4), 185-198; https://doi.org/10.3390/appliedchem2040013 - 29 Sep 2022
Viewed by 1969
Abstract
Laminaria hyperborea (Gunnerus) Foslie 1885 is a seaweed native to the North Atlantic, which is utilized in the production of alginate. Its potential as a source of bioactive lipids remains unexplored. In this study, mono- and digalactosyldiacylglycerols (MGDG and DGDG) were identified in [...] Read more.
Laminaria hyperborea (Gunnerus) Foslie 1885 is a seaweed native to the North Atlantic, which is utilized in the production of alginate. Its potential as a source of bioactive lipids remains unexplored. In this study, mono- and digalactosyldiacylglycerols (MGDG and DGDG) were identified in stipe and blade from L. hyperborea for the first time. Samples were harvested off the west coast of Norway in May 2018. Lipids were extracted with chloroform:methanol (2:1, v/v) and fractionated using solid phase extraction, whereupon the fatty acid content was determined by gas chromatography-mass spectrometry. The fatty acid profile was used to predict the mass of the glyceroglycolipids. A total of 103 and 161 molecular species of MGDG, and 66 and 136 molecular species of DGDG were identified in blade and stipe, respectively, by HPLC-ESI-MS/MS. The most abundant molecular species were identified from the total ion chromatograms. According to these, MGDG(20:5/18:4, 18:4/18:4, 16:0/18:1, 14:0/18:2, 14:0/18:1) and DGDG(20:5/18:4, 16:0/18:1, 14:0/18:1) were the most abundant in blade. On the other hand, in stipe, the most abundant molecular species were MGDG (14:0/18:2, 14:0/18:1, 16:0/18:1) and DGDG (14:0/18:1). The purpose of this study is to highlight the potential application of L. hyperborea in a biotechnological context. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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11 pages, 12067 KiB  
Article
The Effect of Cation Exchange on the Pore Geometry of Zeolite L
by Lisa A. Price, Zöe Jones, Antony Nearchou, Gavin Stenning, Daniel Nye and Asel Sartbaeva
AppliedChem 2022, 2(3), 149-159; https://doi.org/10.3390/appliedchem2030011 - 15 Jul 2022
Cited by 1 | Viewed by 1890
Abstract
Zeolites with the LTL framework topology are attractive materials for use in optoelectronics, gas adsorption and as chemical reactors. This is due to their unique, one-dimensional (1D) channel systems which are large enough to act as hosts for organic dye molecules and other [...] Read more.
Zeolites with the LTL framework topology are attractive materials for use in optoelectronics, gas adsorption and as chemical reactors. This is due to their unique, one-dimensional (1D) channel systems which are large enough to act as hosts for organic dye molecules and other guest materials. Here, we use high-resolution X-ray diffraction to show the effect of cation exchange on the pore geometry of LTL-type zeolites. The nature of the exchanging cation is shown to influence the free access diameter, volume and water content of the 12-ring (12R) channel systems. As such, cation exchange can be used to tune the molecular sieving and adsorption properties of LTL-type zeolites. This offers new possibilities for these materials in technologically relevant applications. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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7 pages, 2170 KiB  
Article
Stereoselective Synthesis and Isolation of (±)-trans,trans-Cyclohexane-1,2,4,5-tetraol
by Andreia A. Rosatella and Carlos A. M. Afonso
AppliedChem 2022, 2(3), 142-148; https://doi.org/10.3390/appliedchem2030010 - 12 Jul 2022
Viewed by 1500
Abstract
Cyclohexanetetrols belong to the family of cyclitols, a class of natural products known for their diverse bioactivity. Their synthesis has been reported using hydrogen peroxide as a green oxidant and water or tert-butanol as a solvent. Due to the high polarity of [...] Read more.
Cyclohexanetetrols belong to the family of cyclitols, a class of natural products known for their diverse bioactivity. Their synthesis has been reported using hydrogen peroxide as a green oxidant and water or tert-butanol as a solvent. Due to the high polarity of those compounds, a green approach for their isolation from aqueous solutions can be challenging. Here, we report the stereoselective synthesis of (±)-trans,trans-cyclohexane-1,2,4,5-tetraol combined with a novel isolation method, where is possible the isolation of the product in excellent yield without the need for derivatization, column chromatography or organic solvent extraction. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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14 pages, 1982 KiB  
Article
pH-Sensitive Sensors at Work on Poultry Meat Degradation Detection: From the Laboratory to the Supermarket Shelf
by Lisa Rita Magnaghi, Camilla Zanoni, Elena Bancalari, Jasmine Hadj Saadoun, Giancarla Alberti, Paolo Quadrelli and Raffaela Biesuz
AppliedChem 2022, 2(3), 128-141; https://doi.org/10.3390/appliedchem2030009 - 24 Jun 2022
Cited by 2 | Viewed by 2070
Abstract
In the last twenty years, the number of publications presenting generalized pH-sensitive devices proposed for food freshness monitoring has been steadily growing, but to date, none of them have succeeded in exiting the laboratory and reaching the supermarket shelf. To reach this scope, [...] Read more.
In the last twenty years, the number of publications presenting generalized pH-sensitive devices proposed for food freshness monitoring has been steadily growing, but to date, none of them have succeeded in exiting the laboratory and reaching the supermarket shelf. To reach this scope, we developed a large-scale applicable pH-sensitive sensor array to monitor perishable foods’ degradation. We ensured freshness monitoring in domestic conditions, using sales packages and during chilled storage, by simple naked-eye readout and multivariate imaging analysis, and we fully corroborated the device by (i) projection of unknown independent samples in the PCA model, (ii) TVB-N quantification and (iii) microbiological assay. The choice of commercial and cheap dye and polymeric support already employed in food packaging ensures the low-cost and scalability of the device and the promising results obtained make this device an eligible candidate for large-scale implementation. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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13 pages, 3686 KiB  
Article
Comparative Study of Various Graphene Oxide Structures as Efficient Drug Release Systems for Ibuprofen
by Panagiota Zygouri, Konstantinos Spyrou, Demetrios K. Papayannis, Georgios Asimakopoulos, Evangelia Dounousi, Haralambos Stamatis, Dimitrios Gournis and Petra Rudolf
AppliedChem 2022, 2(2), 93-105; https://doi.org/10.3390/appliedchem2020006 - 06 Jun 2022
Viewed by 2346
Abstract
Ibuprofen is a non-steroidal, anti-inflammatory drug that is widely prescribed for its analgesic, antipyretic, and anti-inflammatory actions to treat pain, symptoms of rheumatoid arthritis and fever, but it is also known to cause stomach-related side effects. The development of efficient drug delivery systems [...] Read more.
Ibuprofen is a non-steroidal, anti-inflammatory drug that is widely prescribed for its analgesic, antipyretic, and anti-inflammatory actions to treat pain, symptoms of rheumatoid arthritis and fever, but it is also known to cause stomach-related side effects. The development of efficient drug delivery systems for this compound to prevent these side effects is hampered by its poor water solubility. In this work, we show that graphite oxide and its derivatives have great potential as effective drug delivery systems not only to overcome side effects but also to increase the short biological half-life of ibuprofen. We studied the adsorption capacity of graphite oxide and carboxylated and sulfonated graphene oxide for this drug and its release in simulated gastric and intestinal fluid. The obtained compounds were characterized by X-ray diffraction, thermogravimetric analysis and Fourier transform infrared spectroscopy. DFT calculations were conducted to elucidate the Ibuprofen/host interactions, to establish which properties of these carbon nanomaterials control the loading and release, as well as to provide a better understanding of the orientation of the drug molecules on the single-layer GO. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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9 pages, 1318 KiB  
Article
An Asymmetric Intramolecular Rauhut-Currier Reaction Initiated by Chiral Selenolate-BINOL Complexes
by Gabriela Całka-Kuc and Szymon Buda
AppliedChem 2022, 2(2), 59-67; https://doi.org/10.3390/appliedchem2020004 - 19 Apr 2022
Viewed by 2134
Abstract
This work reports the new method of Rauhut-Currier reaction (RC) with the use of lithium selenolates, which provided up to 80% yield in a non-asymmetric IRC reaction. Therefore, our paper involves the search for an efficient chiral additive in the asymmetric version. The [...] Read more.
This work reports the new method of Rauhut-Currier reaction (RC) with the use of lithium selenolates, which provided up to 80% yield in a non-asymmetric IRC reaction. Therefore, our paper involves the search for an efficient chiral additive in the asymmetric version. The influence of various reaction parameters, such as solvent, additives, temperature, and time, was examined. The results for the non-asymmetric version were significantly higher with the presence of water, but surprisingly different observations were obtained in the asymmetric version. Here, the chiral scandium complex with tertiary amine played an important role. The reaction carried out in the presence of chiral complexes gave the expected product with up to 60% yield and up to 70% ee. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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11 pages, 1516 KiB  
Article
The Influence of Soaking and Sprouting on the Physicochemical Characteristics of Tigernut Tubers (Cyperus esculentus L.)
by Djomdi, Hamadou Bakari, Olivier Gibert, Thierry Tran, Richard Ejoh, Gwendoline Christophe, Philippe Michaud and Robert Ndjouenkeu
AppliedChem 2022, 2(2), 48-58; https://doi.org/10.3390/appliedchem2020003 - 22 Mar 2022
Cited by 1 | Viewed by 2744
Abstract
The influence of soaking and germination on the physicochemical characteristics of tigernut tubers (Cyperus esculentus L.) are investigated. Tubers (Ø > 1 cm) were soaked in an ascorbic acid solution (0.1%) for 48 h at 40 °C before undergoing germination for 6 [...] Read more.
The influence of soaking and germination on the physicochemical characteristics of tigernut tubers (Cyperus esculentus L.) are investigated. Tubers (Ø > 1 cm) were soaked in an ascorbic acid solution (0.1%) for 48 h at 40 °C before undergoing germination for 6 days. The textural profile, the capacity and germination energy and the biochemical composition of these tubers were determined. The germination energy varied from 76.18 to 79.48% for the quantities of solution of 24 and 48 mL, respectively. The textural profile of the tubers varied depending on the type of treatment. Germination resulted in a considerable reduction in amylose content from 14.15% for the native tigernut tuber to 9.98% for the sprouted one. This treatment also increased the protein, ascorbic acid and ash contents, which ranged from 7.54 to 8.82 g/100 g DM, 250 to 275.39 mg/100 g DM and 2.60 to 3.84 g/100 g DM, respectively. The starch content of the tubers following germination remained high, which could come up against the pasteurization of the milk from these tubers. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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18 pages, 3464 KiB  
Article
Application of a Universal Calibration Method for True Molar Mass Determination of Fluoro-Derivatized Technical Lignins by Size-Exclusion Chromatography
by Esakkiammal Sudha Esakkimuthu, Nathalie Marlin, Marie-Christine Brochier-Salon and Gérard Mortha
AppliedChem 2022, 2(1), 30-47; https://doi.org/10.3390/appliedchem2010002 - 03 Mar 2022
Cited by 1 | Viewed by 2737
Abstract
The determination of the true molar mass distribution (MMD) of lignin is highly important to understand the physicochemical characteristics for lignin-based value-added applications. It is imperative to develop a universal method to quantify accurate MMD of lignin using size exclusion chromatography (SEC), as [...] Read more.
The determination of the true molar mass distribution (MMD) of lignin is highly important to understand the physicochemical characteristics for lignin-based value-added applications. It is imperative to develop a universal method to quantify accurate MMD of lignin using size exclusion chromatography (SEC), as the conventional method with polymer standards provides irregular MMD results. This work aims to evaluate the MMD of five lignin samples (Protobind 1000, Organosolv, Indulin, Pine Kraft and Eucalyptus Kraft) in THF. Different derivatization methods (acetylation, fluorobenzylation and fluorobenzoylation) were performed. FTIR and 19F NMR analyses were used to follow derivatization. The MMDs of derivatized and underivatized lignins were determined by the conventional method and compared with the universal calibration method developed using intrinsic viscosity. The 19F NMR spectra provided the information to quantify the degree of substitution of lignin hydroxyl groups, to calculate the true molar mass of the derivatives of lignin monomers. The obtained MMDs values for all the derivatized lignin by universal calibration were found to be three to five times higher than that of the conventional calibration. The polydispersity values obtained with the acetylation method were higher than the fluoro-derivatives. The results demonstrated that fluoro-derivatization is an appropriate method to apply to higher molar mass technical lignins and lacks solubility and aggregation issues. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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11 pages, 2194 KiB  
Article
Hydrogels Made of Poly-γ-Glutamic Acid and Sugar Alcohols for Enhanced Survival of Probiotic Strains Subjected to Low pH and Freeze Drying
by Iwona Kwiecień, Anabel Itohowo Ekere and Monika Śmiga-Matuszowicz
AppliedChem 2021, 1(2), 173-183; https://doi.org/10.3390/appliedchem1020013 - 13 Dec 2021
Viewed by 2675
Abstract
Probiotics are microorganisms that have a beneficial influence on the human gastrointestinal tract. Unfortunately, their viability can be negatively affected by manufacturing, storage conditions and gastrointestinal tract conditions. Therefore, there is a need to develop delivery systems, which can protect probiotics against adverse [...] Read more.
Probiotics are microorganisms that have a beneficial influence on the human gastrointestinal tract. Unfortunately, their viability can be negatively affected by manufacturing, storage conditions and gastrointestinal tract conditions. Therefore, there is a need to develop delivery systems, which can protect probiotics against adverse conditions. Previously, we reported on hydrogels made of poly-γ-glutamic acid (γ-PGA) and selected PEGs with the potential application as probiotic delivery vehicles. In the next step of research, we decided to develop fully biobased hydrogels with the potential application as probiotic oral-delivery systems. Selected sugar alcohols, erythritol, xylitol and sorbitol, have been used as cross-linkers in the synthesis of γ-PGA-based hydrogels. It was examined if obtained hydrogels enhanced the survival rate of entrapped probiotic strains subjected to acidic conditions. Results have been discussed in relation to the previously reported γ-PGA-PEG hydrogels. Moreover, the possibility of using developed hydrogels as a cryoprotectant was investigated during freeze drying of entrapped probiotic cells. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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17 pages, 7508 KiB  
Article
Characterization of Potential Pollutants from Poly(lactic acid) after the Degradation Process in Soil under Simulated Environmental Conditions
by Marta Krawczyk-Walach, Karolina Gzyra-Jagieła, Anna Milczarek and Jagoda Jóźwik-Pruska
AppliedChem 2021, 1(2), 156-172; https://doi.org/10.3390/appliedchem1020012 - 10 Dec 2021
Cited by 5 | Viewed by 3488
Abstract
In recent years, the amount of produced petrochemical plastic waste has been growing at an alarming rate. According to the Plastics Europe Market Research Group (PEMRG)/Conversio Market & Strategy GmbH, in 2018 the global production of plastics amounts to 359 million tons, and [...] Read more.
In recent years, the amount of produced petrochemical plastic waste has been growing at an alarming rate. According to the Plastics Europe Market Research Group (PEMRG)/Conversio Market & Strategy GmbH, in 2018 the global production of plastics amounts to 359 million tons, and in Europe—61.8 million tons. More than 80% of all marine litter is plastic, which accumulates in the environment due to its durability. Due to the growing problem, biodegradable polymer products are introduced to the market. Therefore, it is necessary to conduct research on degradation products in order to estimate the risk arising from their presence in the environment. This paper discusses research on compounds that may potentially remain in the soil after the degradation of the double green PLA polymer. The aim of the research was to prove whether products made of PLA, e.g., packaging, films and other waste can release substances harmful to the environment. Therefore, soil was selected as a medium to characterize the substances potentially released from the polymer under conditions simulating the degradation process in the environment. The soil was always used from the same producer. Before the polymer biodegradation process, it was additionally checked for pH, C and N content, number of microorganisms, etc. PLA degradation in soil was carried out in a laboratory accredited by the Polish Accreditation Center (PCA). During the research, soil samples at various stages of the degradation process under laboratory conditions were subjected to both extraction in an aqueous environment and organic solvent extraction The studies used the gas chromatography coupled with mass spectrometry (GC/MS), as well as pyrolysis gas chromatography (Py-GC/MS). In addition, the study used the gel permeation chromatography (GPC/SEC) allowing to determine the distribution of molar masses, average molar masses and polydispersity, and the infrared spectroscopy (FTIR). Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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14 pages, 4856 KiB  
Article
Nonenzymatic Deamidation Mechanism on a Glutamine Residue with a C-Terminal Adjacent Glycine Residue: A Computational Mechanistic Study
by Haruka Asai, Koichi Kato, Tomoki Nakayoshi, Yoshinobu Ishikawa, Eiji Kurimoto, Akifumi Oda and Nobuyuki Fukuishi
AppliedChem 2021, 1(2), 142-155; https://doi.org/10.3390/appliedchem1020011 - 08 Dec 2021
Cited by 2 | Viewed by 3363
Abstract
The deamidation of glutamine (Gln) residues, which occurs non-enzymatically under physiological conditions, triggers protein denaturation and aggregation. Gln residues are deamidated via the cyclic glutarimide intermediates to l-α-, d-α-, l-β-, and d-β-glutamate residues. The production of these biologically uncommon [...] Read more.
The deamidation of glutamine (Gln) residues, which occurs non-enzymatically under physiological conditions, triggers protein denaturation and aggregation. Gln residues are deamidated via the cyclic glutarimide intermediates to l-α-, d-α-, l-β-, and d-β-glutamate residues. The production of these biologically uncommon amino acid residues is implicated in the pathogenesis of autoimmune diseases. The reaction rate of Gln deamidation is influenced by the C-terminal adjacent (N +1) residue and is highest in the Gln-glycine (Gly) sequence. Here, we investigated the effect of the (N + 1) Gly on the mechanism of Gln deamidation and the activation barrier using quantum chemical calculations. Energy-minima and transition-state geometries were optimized by the B3LYP density functional theory, and MP2 calculations were used to obtain the single-point energy. The calculated activation barrier (85.4 kJ mol−1) was sufficiently low for the reactions occurring under physiological conditions. Furthermore, the hydrogen bond formation between the catalytic ion and the main chain of Gly on the C-terminal side was suggested to accelerate Gln deamidation by stabilizing the transition state. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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12 pages, 1668 KiB  
Article
Organic Ion-Associate Phase Microextraction/Back-Microextraction for Preconcentration: Determination of Nickel in Environmental Water Using 2-Thenoyltrifluoroacetone via GF-AAS
by Mitsuhito Kosugi, Kenta Mizuna, Kazuto Sazawa, Takuya Okazaki, Hideki Kuramitz, Shigeru Taguchi and Noriko Hata
AppliedChem 2021, 1(2), 130-141; https://doi.org/10.3390/appliedchem1020010 - 01 Dec 2021
Cited by 3 | Viewed by 3036
Abstract
An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts of nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent for nickel, but also as a component of the extraction [...] Read more.
An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts of nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent for nickel, but also as a component of the extraction phase, i.e., IAP. Nickel in a 40 mL sample solution was pH-adjusted with phenolsulfonate (PS) and tetramethylammonium hydroxide and converted by chelation reaction in the presence of thenoyltrifluoroacetonate (TTA). When benzyldodecyldimethylammonium ion (C12BzDMA+) was added, a suspension of IAP formed in the solution. The IAP consisted of TTA, a chelating reagent, the PS, a component of pH buffer, and C12BzDMA+, which helps extract the chelating complex. When the solution was centrifuged, the IAP separated from the suspension and the nickel-TTA chelate was extracted into the bottom phase of the centrifuge tube. After the aqueous phase was taken away, 100 µL of nitric acid (2 M) solution containing phosphate was used to back-microextract nickel from the IAP. The acid phase was measured via graphite-furnace atomic-absorption spectrometry (GF-AAS). The proposed method facilitated a 400-fold enrichment. The limit of detection was 0.02 µg L−1. The proposed method was applied for the determination of nickel in river water and seawater samples. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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19 pages, 902 KiB  
Article
Group Contribution Revisited: The Enthalpy of Formation of Organic Compounds with “Chemical Accuracy” Part II
by Robert J. Meier
AppliedChem 2021, 1(2), 111-129; https://doi.org/10.3390/appliedchem1020009 - 15 Nov 2021
Cited by 6 | Viewed by 2786
Abstract
Group contribution (GC) methods to predict thermochemical properties are eminently important to process design. We present a group contribution parametrization for the heat of formation of organic molecules exhibiting chemical accuracy, maximum 1 kcal/mol (4.2 kJ/mol) difference between experiment and model values while [...] Read more.
Group contribution (GC) methods to predict thermochemical properties are eminently important to process design. We present a group contribution parametrization for the heat of formation of organic molecules exhibiting chemical accuracy, maximum 1 kcal/mol (4.2 kJ/mol) difference between experiment and model values while minimizing the number of parameters avoiding overfitting and therewith avoiding reduced predictability. Compared to the contemporary literature, this was successfully achieved by employing available literature high-quality and consistent experimental data, optimizing parameters group by group, and introducing additional parameters when chemical understanding was obtained supporting these. A further important result is the observation that the applicability of the group contribution approach breaks down with increasing substitution levels, i.e., more heavily alkyl-substituted molecules, the reason being a serious influence of substitution on the conformation of the flexible part of the entire molecule within particular valence angles and torsional angles affected, which cannot be accounted for by additional GC parameters with fixed numerical values. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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21 pages, 16425 KiB  
Article
Opoka—Sediment Rock as New Type of Hybrid Mineral Filler for Polymer Composites
by Robert E. Przekop, Paulina Jakubowska, Bogna Sztorch, Rafał Kozera, Kamil Dydek, Marek Jałbrzykowski, Tomasz Osiecki, Piotr Marciniak, Agnieszka Martyła, Arkadiusz Kloziński and Dariusz Brząkalski
AppliedChem 2021, 1(2), 90-110; https://doi.org/10.3390/appliedchem1020008 - 03 Nov 2021
Cited by 6 | Viewed by 3770
Abstract
The work presents a comprehensive profile of the physicochemical characteristics of opoka sedimentary rock in the context of its use as a hybrid filler for thermoplastics. Determining the functional parameters of the studied filler was the main aim of this research. Thermal treatment [...] Read more.
The work presents a comprehensive profile of the physicochemical characteristics of opoka sedimentary rock in the context of its use as a hybrid filler for thermoplastics. Determining the functional parameters of the studied filler was the main aim of this research. Thermal treatment leads to changes in its morphology and phase composition. A wide range of physicochemical techniques was used, such as low-temperature nitrogen adsorption, FT-IR, TGA, XRD, optical, and electron microscopy. The susceptibility of the material to micronisation was also tested (ball milling). Due to its widespread occurrence, opoka can be an attractive alternative to fillers such as silica or chalk. In order to verify this statement, polypropylene composites thereof were prepared by melt blending and injection molding, and studied by mechanical testing and microscopic imaging. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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Review

Jump to: Research

29 pages, 922 KiB  
Review
Comprehensive Review of the Components in Cat’s Claw (Uncaria tomentosa) and Their Antibacterial Activity
by Jason J. Blanck, Thomas M. Huebner, Alyssa M. Rolls, Josh S. Cornell and Candy S. Hwang
AppliedChem 2022, 2(1), 1-29; https://doi.org/10.3390/appliedchem2010001 - 22 Feb 2022
Viewed by 5653
Abstract
Cat’s claw (Uncaria tomentosa (Willd. ex Schults) DC.), a plant that is exceptionally rich in phytochemicals, has been used for centuries by the indigenous people of South and Central America as a therapeutic and is currently widely exported for medicinal purposes. Extracts [...] Read more.
Cat’s claw (Uncaria tomentosa (Willd. ex Schults) DC.), a plant that is exceptionally rich in phytochemicals, has been used for centuries by the indigenous people of South and Central America as a therapeutic and is currently widely exported for medicinal purposes. Extracts and individual components have shown considerable potential as antibacterials in the literature. The purpose of this review is twofold: first, to provide a substantiated, comprehensive collection of the known chemical constituents of U. tomentosa, including their detailed structures; second, to identify those components that offer some promise as antibacterials based on the research to date. Bacterial resistance to currently available antibiotics continues to increase and is widely recognized as an impending, potentially catastrophic, problem. There is research to suggest that U. tomentosa components may have antibacterial potential individually or synergistically with established antibiotics against microbes, including Borrelia burgdorferi, the causative agent of Lyme disease. It is our intention that this review will provide a valuable resource to investigators in search of new antimicrobials to meet the daunting challenge of antibiotic resistance. Full article
(This article belongs to the Special Issue Feature Papers in AppliedChem)
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