Machine learning-based prediction of heat transfer performance in annular fins with functionally graded materials

This paper presents a study investigating the performance of functionally graded material (FGM) annular fins in heat transfer applications. An annular fin is a circular or annular structure used to improve heat transfer in various systems such as heat exchangers, electronic cooling systems, and power generation equipment. The main objective of this study is to analyze the efficiency of the ring fin in terms of heat transfer and temperature distribution. The fin surfaces are exposed to convection and radiation to dissipate heat. A supervised machine learning method was used to study the heat transfer characteristics and temperature distribution in the annular fin. In particular, a feedback architecture with the BFGS Quasi-Newton training algorithm (trainbfg) was used to analyze the solutions of the mathematical model governing the problem. This approach allows an in-depth study of the performance of fins, taking into account various physical parameters that affect its performance. To ensure the accuracy of the obtained solutions, a comparative analysis was performed using guided machine learning. The results were compared with those obtained by conventional methods such as the homotopy perturbation method, the finite difference method, and the Runge-Kutta method. In addition, a thorough statistical analysis was performed to confirm the reliability of the solutions. The results of this study provide valuable information on the behavior and performance of annular fins made from functionally graded materials. These findings contribute to the design and optimization of heat transfer systems, enabling better heat management and efficient use of available space.

Regression analysis for the determination of microplastics in sediments using differential scanning calorimetry

This research addresses the growing need for fast and cost-efficient methods for microplastic (MP) analysis. We present a thermo-analytical method that enables the identification and quantification of different polymer types in sediment and sand composite samples based on their phase transition behavior. Differential scanning calorimetry (DSC) was performed, and the results were evaluated by using different regression models. The melting and crystallization enthalpies or the change in heat capacity at the glass transition point were measured as regression analysis data. Ten milligrams of sea sand was spiked with 0.05 to 1.5 mg of microplastic particles (size: 100 to 200 µm) of the semi-crystalline polymers LD-PE, HD-PE, PP, PA6, and PET, and the amorphous polymers PS and PVC. The results showed that a two-factorial regression enabled the unambiguous identification and robust quantification of different polymer types. The limits of quantification were 0.13 to 0.33 mg and 0.40 to 1.84 mg per measurement for semi-crystalline and amorphous polymers, respectively. Moreover, DSC is robust with regard to natural organic matrices and allows the fast and non-destructive analysis of microplastic within the analytical limits. Hence, DSC could expand the range of analytical methods for microplastics and compete with perturbation-prone chemical analyses such as thermal extraction-desorption gas chromatography-mass spectrometry or spectroscopic methods. Further work should focus on potential changes in phase transition behavior in more complex matrices and the application of DSC for MP analysis in environmental samples.

Crystal growth, Hirshfeld analysis, optical, thermal, mechanical, and third-order non-linear optical properties of Cyclohexylammonium picrate (CHAP) single crystal

The organic single crystals of Cyclohexylammonium picrate (CHAP) had been grown using the method of slow evaporation solution growth. A determination was made regarding the solubility of the substance. The crystal's lattice cell parameters and morphology were characterized using single-crystal X-ray diffraction and powder X-ray diffraction techniques. The HRXRD techniques were utilized to assess the crystal quality. The functional groups of CHAP material were identified through the use of FT-IR and FT-Raman analysis. A Hirshfeld surface analysis was performed to investigate the formation of hydrogen bonds between N-H⋯O and C-H⋯O molecules. The grown crystals were examined in optical and thermal investigations utilizing UV-visible and TGA, DSC techniques. Mechanical analysis is used to quantify surface properties, such as work hardening coefficient and void volume. Z-scan analysis was utilized to calculate the non-linear refractive index (n2), nonlinear absorption (β), and third-order non-linear susceptibility (χ3).

Anti-inflammatory and anti-rheumatic effects of Phoenix dactylifera L. (date palm) seed by controlling cytokines and inhibiting JAK1/STAT3 pathway on CFA-induced arthritis rat and its phytochemical profiling

ETHNOPHARMACOLOGICAL RELEVANCE

Phoenix dactylifera L. (date palm) seed is widely used in Arabian traditional medicine to alleviate several health problems including inflammatory conditions. The herbal tea of date palm seed has been consumed by rheumatoid patients to relief their symptoms.

AIM OF THE STUDY

The purpose of this study was to investigate the claimed beneficial use of P. dactylifera L. (Sewy variety) seed (PDS) in the treatment of rheumatoid arthritis (RA) and its mechanism of action as well as to study its phytoconstituents.

MATERIALS AND METHODS

The anti-inflammatory and anti-oxidative properties of the non-polar and the polar extracts of PDS were studied using Complete Freund's adjuvant (CFA)-induced arthritis rat model. Paw edema, body weight, total nitrate/nitrite NOX content and cytokine markers were evaluated to monitor the progress of arthritis. Also, histological examination and thermal analysis were conducted. The phytoconstituent profiles of non-polar and polar extracts of PDS were investigated using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). The multiple reactions monitoring mode (MRM) of liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was used to quantify phenolic phytoconstituents in both extracts.

RESULTS

According to the findings, the polar and non-polar PDS extracts kept body weight comparable to those of healthy individuals while considerably lowering paw swelling, edema, and neutrophil infiltration. It also reduced the levels of Nuclear Factor Kappa B (NF-κB), Tumor Necrosis Factor Alpha (TNF-α), Interleukin 22, Interleukin 23, Interferon (IFN), Interleukin 17, Interleukin 1β, Interleukin 6, Interleukin 36, Janus Kinase 1 (JAK1), and Signal Transducer and Activator of Transcription 3 (STAT3). They also reduced the degenerative alterations caused by RA. Thermal research gave additional support for these findings. 83 phytoconstituents were identified in the non-polar PDS extract and 86 phytoconstituents were identified in the polar PDS extract. 74 of the identified phytoconstituents were common in both extracts. 33 phytoconstituents were identified here from P. dactylifera for the first time as far as we know. In MRM-LC-ESI-MS/MS analysis, the major phenolics in both extracts were chlorogenic acid, naringenin, and vanillin. Catechin was only detected in the non-polar PDS extract. On the other hand, apigenin, kaempferol, and hesperetin were only detected in the polar PDS extract. Generally, the polar PDS extract showed higher concentrations of the identified phenolics than the non-polar extract.

CONCLUSIONS

The PDS extracts especially the non-polar extract showed significant anti-inflammatory and anti-oxidative properties in the CFA-induced arthritis rat model. PDS might be used to produce RA medicines.

Development and characterization of co-amorphous griseofulvin/L-leucin by modified solvent processing hot-melt extrusion

Co-amorphous systems (CAMS) were developed between griseofulvin (GRI) and L-leucine (LEU) at 2:1 wt ratio, by application of a novel solvent assisted hot-melt extrusion (HME) method that involved wet processing/drying of the feeds prior to extrusion. CAMS formation was confirmed by powder crystallography (pXRD) and thermal analysis (DSC). Intermolecular H-bonding between the carbonyl groups of GRI and the hydroxyl and amino groups of LEU were identified by vibrational spectroscopy (ATR-FTIR). The measured glass transition temperatures (Tg) of the extrudates from feeds processed with aqueous acetic acid (AcOH) were markedly lower than that of neat amorphous GRI and values predicted from Gordon-Taylor equation, indicating plasticizing action of AcOH. Drug concentrations during dissolution of CAMS under non-sink conditions (Sink Index 0.0115) were up to x82 higher at plateau compared to crystalline drug solubility. The degree of supersaturation lasted for at least 24 h. Plasticizer (Compritol®/Kolliphor® 75/25) added before extrusion did not impact significantly on CAMS formation but altered the dissolution profile from a spring-and-parachute profile to gradual rise to maximum. These findings reinforce the application of drug/amino acid-based CAMS in formulation, particularly for high-dose drugs, for which polymers are unsuited due to the required large proportions.

Preparation and formulation of progesterone para-aminobenzoic acid co-crystals with improved dissolution and stability

The crystal structure of a new Progesterone (PROG) co-crystal with para-aminobenzoic acid (PABA) showing enhanced solution properties is reported. PROG-PABA co-crystal was first identified though an in silico coformer screening process using the CSD Co-crystal deign function, then confirmed through a solution evaporation crystallisation experiment. The resulting co-crystal was characterized using single crystal X-ray diffraction, differential scanning calorimetry and Fourier-transform infrared spectroscopy. Liquid assisted grinding was selected as a suitable scale up method compared to spray drying and antisolvent methods due to minimal starting material phases in the final product. Following scale up, aqueous solubility, stability and dissolution measurements were carried out. PROG-PABA showed increased distinct aqueous solubility and dissolution compared to PROG starting material and was shown to be stable at 75 % relative humidity for 3 months. Tablets containing co-crystal were produced then compared to the Utrogestan® soft gel capsule formulation through a dissolution experiment. PROG-PABA tablets showed a substantial increase in dissolution over the course of the experiment with over 30× the amount of PROG dissolved at the 3-hour time point. This co-crystal shows positive implications for developing an improved oral PROG formulation.

On thermal characterization method of integrated magnetic components

The operating temperature of integrated magnetic components can be critical. Excessively high temperature can significantly modify the properties of components, especially those of magnetic material, such as saturation magnetization and magnetic permeability. This article introduces an experimental characterization method using two different sensors. We compare the results obtained from these sensors. Initially, the method is validated using a "meander component, and subsequently, it is applied to planar spiral inductors, both with and without magnetic material.

Design, synthesis, characterization, in vitro cytotoxic, antimicrobial, antioxidant studies, DFT, thermal and molecular docking evaluation of biocompatible Co(II) complexes of N4O4-macrocyclic ligands

Bioactive cobalt (II) macrocyclic complexes [Co(N4O4ML1)Cl2]-[Co(N4O4ML3)Cl2] have been synthesized by using the macrocyclic ligands [N4O4ML1], [N4O4ML2], and [N4O4ML3] that have an N4O4 core. These three macrocyclic ligands were all isolated in pure form, together with their complexes. Microanalytical investigations, FT-IR NMR, Mass, magnetic moments, electronic, PXRD, TGA, and EPR spectrum studies were used to analyse their structures. For these complexes, an octahedral geometry is proposed for the metal ion. By using molecular weights and conductivity measurements the monomeric and non-electrolytic nature has been confirmed. The Coats-Redfern and FWO methods are used to determine the thermodynamic characteristics of the ligands and their Co(II) complexes. The molecular modelling using the DFT technique displays the bond angle, bond lengths and quantum chemical properties. To determine their ability to prevent the growth of harmful fungus and bacteria, the ligands [N4O4ML1]- [N4O4ML3] and their complexes were tested in vitro against A. Niger, C. albicans and B. subtilis, S. aureus, E. coli and S. typhi fungal and bacterial organisms, respectively. By using DPPH free radical scavenger assays, the in vitro antioxidant capabilities of each compound were evaluated. The [Co(N4O4ML3)Cl2] antioxidative capabilities revealed significant radical scavenging power. The MTT assay was used to assess the toxicity of all the synthesised compounds under inquiry on MCF-7, HeLa, and A549 cancer cells. The findings revealed that the ligand and the compounds gave outstanding IC50 values in the range of 9.07-36.25 (uM) at a concentration of 25 ppm. Among all the substances evaluated, [Co(N4O4ML3)Cl2] complex was discovered to be the most active and least cytotoxic. Additionally, docking investigations of the produced compounds were carried out in order to validate the biological outcomes.

Triflate's bigger brother: The unprecedented tribrate anion, [Br3 CSO3 ]. Chemistry 2024;30:e202303617. [PMID: 38264922 DOI: 10.1002/chem.202303617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The synthesis of the unprecedented [Br3 CSO3 ]- anion starts with the bromination of phenylmethanesulfonate, C6 H5 OSO2 CH3 , with KOBr leading to C6 H5 OSO2 CBr3 . The formation of the [CBr3 ] moiety has been proved, also by an X-ray structure determination of the compound (triclinic, P-1, a=685.9(2), b=698.1(2), c=1190.2(3) pm, α=93.99(1)°, β=97.42(1)°, γ=94.45(1)°). The ester C6 H5 OSO2 CBr3 can be split under basic conditions. The resulting acid provides access to the yet unknown tribromomethanesulfates ("tribrates"). K[Br3 CSO3 ] ⋅ H2 O, the first tribrate known so far has been characterized comprehensively, including an X-ray structure determination (monoclinic, C2/c, a=2267.1(2), b=1282.25(8), c=2618.2(2) pm, β=111.266(2)°), vibrational spectroscopy and theoretical calculations. Moreover, the thermal analysis shows that, after loss of the crystal water, the tribrate decomposes between 530 and 630 K.

Synthesis, crystal structure, thermal stability and biological study of bis{(2-methoxy-6-[(E)-(propylimino)methyl]phenolato}nickel(II) complex

A Schiff base complex of nickel, bis{(2-methoxy-6-[(E)-(propylimino)methyl]phenolato}nickel(II) was synthesised by condensing bis(2-hydroxy-3-methoxybenzaldehyde) nickel (II) and n-propylamine in methanolic medium. Single crystal X-ray diffraction analysis of the complex revealed it to possess planar geometry with a monoclinic crystal system. The non-isothermal TG/DTA runs on this complex in a high purity (99.99 %) nitrogen environment at atmospheric pressure confirmed the absence of any coordinated water. A sharp endotherm in its DTA shows a melting temperature range of 168-171 °C. It is thermally stable up to 243 °C and decomposes in two steps, yielding NiO and carbon as residue. In addition to the methoxy group (-OCH3), infrared analysis (IR) confirmed the presence of the characteristic azomethine group (-C[bond, double bond]N-) which is also responsible for the biological action. It was further analysed by elemental analyser (C, H, N), 1H and 13C NMR as well as mass spectrometry. It showed considerable antibacterial activity towards Escherichia coli and Staphylococcus aureus when the concentration exceeds 200 μg/ml. The antifungal study shows significant inhibition with the antifungal drug imidazole as a positive control (PC). Small values of MIC, MBC/MIC indicate a lesser quantity of complex is required to inhibit the growth of micro-organisms.

Sensitivity analysis of the thermal performance of a parabolic trough concentrator using Al2O3 and SiO2/Vegetable oil as heat transfer fluid

This paper aims to highlight the use of different heat transfer fluid (HTF) configurations based on vegetable oils in Parabolic Trough Solar Concentrator (PTSC). Rapeseed and jatropha oils as innovative heat transfer materials combined with SiO2 and Al2O3 to obtain six (6) HTF configurations are used in a 1-dimensional PTSC model. The thermophysical properties of the nanofluids are determined from correlations derived from the literature, using Gauss-Seidel method from a numerical code developed in Matlab software. Model validation is obtained. Thermal sensitivity analysis shows that the use of rapeseed increases the thermal efficiency of the PTSC by around 4.21 % compared with jatropha. The use of nanofluids reduces thermal losses within the system due to thermal gradients. For a fixed irradiance and each 1 %-4 % increase in volume fraction, thermal efficiency increases by around 1.96 % when Al2O3/rapeseed is used and by 0.47 % when SiO2/rapeseed is used compared with rapeseed. Similarly, thermal efficiency increases by around 1.98 % when Al2O3/jatropha is used and decreases by around 0.20 % when SiO2/jatropha is used compared with jatropha. However, the positive effects of nanoparticles on thermal conductivity alone are not always sufficient to improve thermal efficiency, and thermal effects on heat capacity should also be considered.

Comparative study on thermo-mechanical, structural and functional properties of pectin extracted from immature wasted apples and commercial pectin

Pectin yield of 22.22 ± 0.98 % (dry basis) was achieved from prematurely dropped Golden Delicious apples, having a light orange hue (hue value: 78.08 ± 0.04) and an overall color difference (ΔE) of 9.92 ± 0.01 compared to commercial pectin (CP). Extracted AP exhibited a lower equivalent weight (725.24 ± 29.73) and higher methoxy content (8.36 ± 0.28 %) in contrast to CP. However, a similar degree of esterification of 71.57 ± 0.79 and 70.55 ± 0.59 %, was observed in AP and CP respectively. Apple pectin demonstrated slight lower galacturonic acid (GalA) content of 68.10 ± 3.94 % in comparison to 72.31 ± 4.62 % of CP, which was further corroborated by reduced intensity in FTIR fingerprint region (912-1025 cm-1). Morphology revealed a sheet-like cloudy appearance indicating a significant presence of associated sugars whereas X-ray diffraction highlighted the highly amorphous nature of AP. AP and CP solutions (3-9 %) displayed a shear-thinning flow and viscoelastic behavior where the loss (G') moduli dominated over the storage moduli (G"). Owing to high degree of esterification, galacturonic acid content (>65 %) that aligns with commercial standards and viscoelastic behavior, the extracted AP holds promise for potential utilization in commercial applications. This study underscores the potential for sustainable utilization of prematurely dropped apples through pectin extraction, contributing to valorization of the wasted bioresource.

Recycling of fiber reinforced composites: Online mass spectrometric tracing, offline physicochemical speciation and toxicological evaluation of a pilot plant pyrolytic conversion

The increasing demand for lightweight materials with exceptional stability and durability has resulted in a significant rise in fiber-reinforced plastic (FRP) production. These materials find applications in various fields. However, the exceptional properties and diverse compositional range of FRPs pose challenges to conventional recycling strategies. Pyrolysis has emerged as a highly promising approach for separating the fibers from the polymer matrix. In this study, we employed thermal analysis coupled with high-resolution mass spectrometry to investigate the pyrolysis process. Representative FRP showed a starting decomposition temperature of 300 °C and bisphenol A, styrene, alkenes, and phenols could be identified. The identified parameters were used to operate a pilot plant with a capacity of up to 50 kg/h FRP, and reactor products were directly analyzed with soft photoionization mass spectrometry. The findings demonstrated good agreement between the pilot plant results and laboratory experiments, particularly for smaller compounds (m/z<200). The non-condensable fraction showed a range of 17 to 22 MJ/m3 as lower heating value. Analysis of the recovered fibers (diameter between 6.20 and 8.05 μm) revealed residual coke, but no toxic fibers were detected, according to the World Health Organization's definition. Yet, the organic coating of the fibers contained small amounts of potentially harmful PAHs. A toxicological assessment using a multicellular in vitro model confirmed the low hazardous potential of the recovered fibers. The findings contribute to developing sustainable and environmentally friendly recycling strategies for FRP while addressing important aspects related to the safety and toxicological implications of the resulting chemicals and fibers.

Utilization of marine and agro-waste materials as an economical and active food packaging: Antimicrobial, mechanical and biodegradation studies of O-Carboxymethyl chitosan/pectin/neem composite films

The present work deals with the eco-friendly preparation of highly degradable food packaging films consisting of O-CMC (O-Carboxymethyl Chitosan) and pectin, incorporated with neem (Azadirachta indica) leaves powder and extract. This study aimed to investigate the tensile properties, antimicrobial activity, biodegradability, and thermal behavior of the composite films. The results of tensile strength and elongation at break, showed that the incorporation of neem leaves powder improved the tensile properties (7.11 MPa) of the composite films compared to the neat O-CMC and pectin films (3.02 MPa). The antimicrobial activity of the films was evaluated against a panel of microorganisms including both gram-positive and gram-negative bacteria as well as fungi. The composite films exhibited excellent antimicrobial activity with a zone of inhibition (12-17.6 mm) against the tested microorganisms. The opacity of the composite films ranges from 1.14 to 4.40 mm-1 and the addition of fiber causes a decrease in opacity value. Biodegradability studies were conducted by Soil burial method and the films demonstrated complete biodegradability within 75 days. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of composite films show that they are thermally stable and might be used in food packaging.

From micro to macro: Physical-chemical characterization of wheat starch-based films modified with PEG200, sodium citrate, or citric acid

Needing to extend the shelf-life of packaged food and the evolving consumer demands led researchers to seek innovative, eco-friendly, and biocompatible packaging solutions. Starch is among the most promising natural and renewable alternatives to non-degradable plastics. Here, we deeply study the structural features of starch films modified by adding citric acid (CA) or sodium citrate (SC) as a cross-linker and polyethylene glycol 200 (PEG200) as a plasticizer and obtained through solvent casting. The substances' influence on starch films was evaluated through Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) and Solid-state Nuclear Magnetic Resonance (ss-NMR) spectroscopies. Films' macroscopic properties, such as swelling index, solubility, thermo-mechanical features, and moisture absorption, were also assessed to foresee potential applications. Proper amounts of CA, CS, and PEG200 improve film properties and inhibit starch chains' retrogradation and recrystallization. Besides, the chemical neighbourhood of nuclei observed through ss-NMR significantly changed alongside the polymer chains' mobility. The latter result indicates a different polymer chain structural organization that could justify the film's higher resistance to thermal degradation and elongation at the break. This methodological approach is effective in predicting the macroscopic behaviour of a polymeric material and could be helpful for the application of such products in food preservation.

Solid Forms of The New Antitrypanosomal 1-(4-Acetamide-Benzenesulfonyl)-Benzimidazole: Preparation and Physicochemical Characterization

This study aimed to investigate the polymorphism of 1-(4-acetamide-benzenesulfonyl)-benzimidazole (PABZI), a newly developed compound with significant activity against Trypanosoma cruzi, the parasite which causes American trypanosomiasis (Chagas disease). Three different crystalline forms of PABZI [a solvent-free form (form I), three isostructural solvates (from isopropanol; acetonitrile-dichloromethane, and methanol-benzene) and a non-isostructural solvate from methanol] were isolated and characterized. The crystal structure of form I was resolved at 173 K and 300 K by single crystal X-ray diffraction. Physicochemical properties, including solubility, dissolution rate, wettability, and solid-state stability were assessed for the two most viable solid forms of PABZI, viz. form I and the isopropanol solvate (PABZI-isoOH). Form I exhibited a higher solubility and dissolution rate, and superior stability towards moisture (40 °C/75 % relative humidity) and UV-Visible light than PABZI-isoOH. Based on the solid-state stability results, form I was selected over PABZI-isoOH for further preclinical studies.

Synthesis, biological and molecular docking studies of pyrimidine-derived bioactive Schiff bases

Pyrimidine which is an important constituent of the genetic material of deoxyribonucleic acid, is identified with a large number of biological activities. Based on this, pyrimidine-derived Schiff bases (1-6) of hydroxy-1-naphthaldehyde were synthesized by using the condensation method. In addition, the molecular docking studies against topoisomerase II DNA gyrase, human hematopoietic cell kinase, urate oxidase from Aspergillus flavus, and cyclin-dependent kinase 8 to explore the antibacterial, antioxidant, antifungal, and anticancer properties respectively and binding affinities through bioinformatics approaches to determine the interaction among active molecules with the receptor. Hence, the computational docking analyses identified that all synthesized pyrimidine Schiff bases (1-6) are active and exhibited better binding affinities as compared to the standard drugs. Furthermore, all the prepared materials were characterized by using nuclear magnetic resonance, infrared, and elemental analysis. Additionally, the phase-transition and thermal decomposition temperatures were determined by differential scanning calorimetry and thermo-gravimetric analysis measurements. Moreover, the structures of pyrimidine-derived Schiff bases 1, 2, 3, 4, and 5 were also confirmed by the X-ray single-crystal diffraction technique. The pyrimidine-derived Schiff bases 5 possess significant antibacterial, antioxidant, antifungal, and anticancer agent properties which confirms its promising biological activities over standard drugs.

Improved Thermal Sensitivity Using Virtual Monochromatic Imaging Derived from Photon Counting Detector CT Data Sets: Ex Vivo Results of CT-Guided Cryoablation in Porcine Liver

PURPOSE

To investigate differences in thermal sensitivity of virtual monoenergetic imaging (VMI) series generated from photon-counting detector (PCD) CT data sets, regarding their use to improve discrimination of the ablation zone during percutaneous cryoablation.

MATERIALS AND METHODS

CT-guided cryoablation was performed using an ex vivo model of porcine liver on a PCD-CT system. The ablation zone was imaged continuously for 8 min by acquiring a CT scan every 5 s. Tissue temperature was measured using fiberoptic temperature probes placed parallel to the cryoprobe. CT-values and noise were measured at the tip of the temperature probes on each scan and on VMI series from 40 to 130 keV. Correlation of CT-values and temperature was assessed using linear regression analyses.

RESULTS

For the whole temperature range of [- 40, + 20] °C, we observed a linear correlation between CT-values and temperature in reference 70 keV images (R2 = 0.60, p < 0.001) with a thermal sensitivity of 1.4HU/°C. For the most dynamic range of [- 15, + 20] °C, the sensitivity increased to 2.4HU/°C (R2 = 0.50, p < 0.001). Using VMI reconstructions, the thermal sensitivity increased from 1.4 HU/°C at 70 keV to 1.5, 1.7 and 2.0HU/°C at 60, 50 and 40 keV, respectively (range [- 40, + 20] °C). For [- 15, + 20]°C, the thermal sensitivity increased from 2.4HU/°C at 70 keV to 2.5, 2.6 and 2.7HU/°C at 60, 50 and 40 keV, respectively. Both CT-values and noise also increased with decreasing VMI keV-levels.

CONCLUSION

During CT-guided cryoablation of porcine liver, low-keV VMI reconstructions derived from PCD-CT data sets exhibit improved thermal sensitivity being highest between + 20 and - 15 °C.

Comprehensive guava fruit data set: Digital and thermal images for analysis and classification

Guava (Psidium guajava) is a nutritious fruit known for its origin in Mexico, Central or South America, and the Caribbean. Its production faces declining levels, infections, and disease outbreaks. This dataset focuses on the early identification of guava diseases using image processing and computer vision. Farmers can detect and address diseases promptly by developing an expert system, increasing yields and reducing economic losses. The technology behind this dataset enables sustainable guava farming and disease prevention. This dataset consists of digital and thermal images of guava fruits, including healthy, damaged, and various diseased conditions such as wilt, Anthracnose, canker, and rot. The images are categorized based on the fruit's maturity level (mature, half-mature, and mature) and captured under different drop heights. The dataset also includes information on the damage-inducing methods, storage conditions, image capture schedule, and specific diseases present. The thermal images were acquired using hot air with controlled temperature and velocity.

Acidogenic fermentation of potato peel waste for volatile fatty acids production: Effect of initial organic load

As a renewable carbon source produced from organic wastes by acidogenic fermentation, volatile fatty acids (VFAs) are important intermediates in chemical and biological fields and beneficial to resource recovery and carbon neutrality. Maximizing VFA production by some strategies without additional chemicals is critical to increasing economic and environmental benefits. In this study, the effects of initial organic load (OL) on the performance of VFA production, variations of intermediate metabolites, and the thermogravimetric properties of potato peel waste (PPW) during batch acidogenic fermentation were studied. The results showed that the concentration of VFAs increased with the increase of initial OL, while the VFA yield decreased with the increase of initial OL. When the initial OL was in the range of 28.4 g VS/L-91.3 g VS/L, the fermentation type of PPW was butyric acid fermentation. The highest butyric acid proportion of 61.3% was achieved with the initial OL of 71.5 g VS/L. With the increase of initial OL, the proportion of acetic acid and the utilization rate of protein in the PPW decreased. VFAs were produced from proteins and carbohydrates in the early stage and mainly produced from carbohydrates in the later stage. The production efficiency of VFA was relatively high with the initial OL of 71.5 g VS/L, because more easily-biodegradable compounds were solubilized. The results showed that suitably increased initial OL could accelerate acidogenesis, reduce hydrolysis time, and increase the proportion of butyric acid. The findings in this work suggest that PPW is a promising feedstock for butyric acid biosynthesis and appropriate initial OL is beneficial to VFA production.

Isoconversional thermal decomposition reaction kinetics of oil palm trunk and rubberwood sawdust for thermochemical conversion processes

Biomass as a raw material has profound implications for thermal conversion processes. It is important to study the relationship between kinetic modeling to depict significant importance in thermal processing by estimating volatile yield and reaction performance during biomass decomposition. This work aimed to determine the thermal decomposition reaction kinetics of non-woody (oil palm trunk (OPT)) and woody (rubberwood sawdust (RWS)) biomass. Devolatilization of biomass is determined by the thermogravimetric analysis (TGA) at three different heating rates (10, 20, and 30 °C/min) using nitrogen as inert gas. The kinetic analysis used isoconversion models of Friedman, Ozawa-Flynn-Wall (OFW), and Kissinger-Akahira-Sunose (KAS). The activation energy varied from 218.4 to 303.8 kJ/mol (Friedman), 235.9 to 299.1 kJ/mol (OFW), and 235.8 to 298.9 kJ/mol (KAS) for OPT; and 199.7 to 228.1 kJ/mol (Friedman), 210.6 to 225.6 kJ/mol (OFW), and 210.7 to 225.2 kJ/mol (KAS) for RWS. The kinetic analysis indicated that RWS and OPT had diverse reaction kinetics, which depend on the reaction rate and order of the reaction. Experimental and theoretical conversion data agreed reasonably well, indicating that these results can be used for future OPT and RWS process modeling. Consistency of results is validated using GC-MS equipped with a pyrolyzer.

A review of the techno-economic potential and environmental impact analysis through life cycle assessment of parabolic trough collector towards the contribution of sustainable energy

Parabolic trough collectors (P.T.Cs) are efficient solar energy harvesting devices utilized in various industries, for instance, space heating, solar cooling, solar drying, pasteurization, sterilization, electricity generation, process heat, solar cooking, and many other applications. However, their usage is limited as the high capital and operating costs; according to the International Renewable Energy Agency's 2020 report, the global weighted average levelized cost of electricity (L.C.O.E) for P.T.Cs was 0.185 $/kWh in 2018. This work analyses the economic, technical, and environmental potential of sustainable energy to increase the use of P.T.Cs in different sectors. To study how self-weight, heat loss, and wind velocity affect P.T.C performance, prototype testing, and wind flow analysis were used. Although P.T.Cs outperform in capacity factor, gross-to-net conversion, and annual energy production, improving their overall efficiency is crucial in reducing total energy production costs. Wire coils, discs, and twisted tape-type inserts can enhance their performance by increasing turbulence and heat transfer area. Improving the system's overall efficiency by enhancing the functioning and operation of individual components will also help decrease total energy production costs. The aim is to minimize the L.C.O.E associated with a P.T.C in order to enhance its economic viability for an extended period. When the nanofluid-oriented P.T.C was included in the conventional P.T.C workings, there was a decrease in the L.C.O.E by 1%. Of all the technologies available, ocean, geothermal, and C.S.P parabolic trough plants generate lower amounts of waste and harmful gases, with average emissions of 2.39%, 2.23%, and 2.16%, respectively, throughout their lifespan. For solar-only and non-hybrid thermal energy storage plants, the range of greenhouse gas emissions is between 20 and 34 kgCO₂ equivalents per megawatt-hour. Coal, natural gas steam turbines, nuclear power plants, bioenergy, solar PV, geothermal, concentrated solar power, hydropower reservoir, hydropower river, ocean, and wind power plants all release greenhouse gases at rates of 1022, 587.5, 110.5, 633, 111, 48, 41, 82.5, 7.5, 12.5, and 41.5 gCO₂-e/kWh, respectively. This information is useful to compare the environmental effect of various energy sources and help us to choose cleaner, more sustainable options for the production of electricity. The ongoing advancements and future scope of P.T.Cs could potentially make them more economically viable for domestic, commercial, and industrial applications.

Characterization of new natural cellulosic fiber from Calamus tenuis (Jati Bet) cane as a potential reinforcement for polymer composites

This study investigates the physical, structural, chemical, thermal, mechanical, and morphological properties of the fibers of Calamus tenuis canes and compares the findings with various lignocellulosic fibers to find the place of these fibers as reinforcements for polymer composites. Chemical analysis confirms the presence of 37.43 ± 1.40% cellulose, 31.06 ± 1.03% hemicellulose, and 28.42 ± 0.81% lignin in Calamus tenuis cane fibers, moreover, the presence of these constituents is also confirmed by Fourier Transformed Infrared Spectroscopic (FTIR) analysis. The X-Ray diffraction (XRD) analysis determines the crystallinity index of 37.38 ± 0.27% and the crystallite size of 0.87 ± 0.03 nm of the samples. The thermogravimetric analysis ensures that the Calamus tenuis cane fibers are thermally stable up to 210 ± 5 °C. The Weibull distribution analysis is employed to estimate the tensile properties of Calamus tenuis canes, which reveal a tensile strength of 37.5 ± 2 MPa, Young's modulus of 1.05 ± 0.08 GPa, and an elongation at break of 18.94 ± 4.26%. The roughness of the fibers' outer surface is confirmed by SEM micrographs and AFM analysis, suggesting that it could enhance the adhesion between fibers and matrix during the fabrication of composites.

Tracking the behavior and characteristics of microplastics using a multi-analytical approach: a case study in two contrasting coastal areas of Japan

The global survey for the presence of microplastics (MPs) in aquatic environments has attracted widespread scientific attention over the past decade. However, evaluating the composition and characteristics of these anthropogenic debris using highly sensitive techniques is still under consideration. This study demonstrates a multidimensional analytical approach, including isotopic and thermogravimetric analyses to evaluate characteristics and behavior of MPs in the environment. The MP samples were collected in two contrasting coastal areas of Japan. The stable carbon isotope (δ¹³C) ratios of field-collected polyethylene (PE), polypropylene (PP), and polystyrene (PS) MPs ranged from -25.6‰ to -31.4‰, -23.4‰ to -30.9‰, and -27.3‰ to -28.6‰, respectively. The detected isotope signatures were similar to those of commercial products. In addition, the differences in δ¹³C signature were determined between MPs with different colors. Through thermal analysis, the single-step endothermic process was observed for environmental PE and PS-MPs. Patterns in the thermograms revealed dissimilarities in degradability among the PE-MPs with different colors. The results reveal that degradation (aging) may play a significant role in the behavior and characteristics of MP debris in the aquatic environment. The present study provides fundamental data of environmental MPs from the isotopic and thermogravimetric aspects and highlights the usefulness of the approach for advances in MP research.

The effects of biochar on soil organic matter pools are not influenced by climate change

The sustainability of Mediterranean croplands is threatened by climate warming and rainfall reduction. The use of biochar as an amendment represents a tool to store organic carbon (C) in soil. The vulnerability of soil organic C (SOC) to the joint effects of climate change and biochar application needs to be better understood by investigating its main pools. Here, we evaluated the effects of partial rain exclusion (∼30%) and temperature increase (∼2 °C), combined with biochar amendment, on the distribution of soil organic matter (SOM) into particulate organic matter (POM) and the mineral-associated organic matter (MAOM). A set of indices suggested an increase in thermal stability in response to biochar addition in both POM and MAOM fractions. The MAOM fraction, compared to the POM, was particularly enriched in labile substances. Data from micro-Raman spectroscopy suggested that the POM fraction contained biochar particles with a more ordered structure, whereas the structural order decreased in the MAOM fraction, especially after climate manipulation. Crystalline Fe oxides (hematite) and a mix of ferrihydrite and hematite were detected in the POM and in the MAOM fraction, respectively, of the unamended plots under climate manipulation, but not under ambient conditions. Conversely, in the amended soil, climate manipulation did not induce changes in Fe speciation. Our work underlines the importance of discretely taking into account responses of both MAOM and POM to better understand the mechanistic drivers of SOC storage and dynamics.

Magnetic circuit optimization design and thermal analysis of the giant magnetostrictive transducer

A giant magnetostrictive transducer was studied. The dynamic simulation analysis of the transducer was carried out, the influence of the magnetic block and the magnetic cylinder on the vibration performance of the transducer was studied, and the temperature rise of the transducer during the operation was simulated and calculated. The impedance and output amplitude of the developed transducer were tested experimentally. The results show that the axial magnetic field intensity of the Terfenol-D rod increased and then decreased, and the output amplitude increased and then decreased slightly with the increase of the thickness of the magnetic cylinder. As the thickness of the magnetic block increased, the axial magnetic field intensity of the rod increased, and the output amplitude of the transducer also increased. Compared with the transducer without magnetic cylinder, the transducer with magnetic cylinder has larger electromechanical conversion coefficient, and output amplitude, but the temperature was higher after working for the same time.

Synthesis, structural characterization, thermal analysis, DFT, biocidal evaluation and molecular docking studies of amide-based Co(II) complexes

Abstract

Many distinct amino acid and aromatic amine-derived transition metal complexes are used as physiologically active compounds. A few Cobalt (II) complexes have been synthesized by reacting cobalt (II) chloride with 1, 8-diaminonapthalene-based tetraamide macrocyclic ligands in an ethanolic media. These synthesized ligands (TAML1-3) and associated Co(II) complexes were fully characterized with various spectroscopic techniques, such as IR, NMR, CHN analysis, EPR, molar conductance, and magnetic susceptibility measurements, TGA, UV-visible spectra, powder X-ray diffraction and DFT analysis. The IR spectra reveal interactions between the core metal atom and ligands through N of 1, 8-diaminonapthalene. The distorted octahedral geometry of synthesized Co(II) macrocyclic complexes were confirmed by ESR, UV-Vis and DFT studies. The synthesized ligands (TAML1-TAML3) and their Co(II) complexes were tested for antimicrobial activity against A. niger, C. albicans, and F. oxysporum in addition to bacteria like S. aureus, B. subtilis, and Gram-negative bacteria like E. coli. The ligand TAML1 and complex [Co(TAML1)Cl2] showed an excellent antibacterial activity. The minimum inhibitory concentration of TAML1 and [Co(TAML1)Cl2] against S. aureus were found to be 7 mm and 10 mm zone of inhibition at 500 ppm, respectively, compared to drug ampicillin (3 mm). Additionally, each molecule exhibited notable antioxidant activity. The biological significance of the synthesized compounds was then evaluated by molecular docking experiments with the active site of the receptor protein such as Sars-Cov-2, C. Albicans, X. campestris and E. coli. The molecular docking assisted data strongly correlated to the experimental approach of antimicrobial activity.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11696-023-02843-y.

TTS package: Computational tools for the application of the Time Temperature Superposition principle

The TTS package has been developed in R software to predict the mechanical properties of viscoelastic materials, at short and long observation times/frequencies by applying the Time Temperature Superposition (TTS) principle. TTS is a physical principle used in material science to estimate mechanical properties beyond the experimental range of observed times/frequencies by shifting data curves obtained at other temperatures relative to a reference temperature in the dataset. It is a methodology related to accelerated life-tests and reliability, whereas the TTS library is one of the first open source computational tool to apply the TTS principle. This R package provides free computational tools to obtain master curves that characterize materials from a thermal-mechanical approach. The TTS package also proposes, implements and explains our own method to obtain the shift factors and the master curve in a TTS analysis, based on horizontal shifting of the first derivative function of viscoelastic properties. This procedure provides shift factors estimates and smooth master curve estimates using B-spline fitting, in a fully automatic way, without assuming any parametric expression. Williams-Landel-Ferry (WLF) and Arrhenius TTS parametric models are also implemented in the TTS package. They can be fitted from shifts obtained by the our first derivative based method.

Synthesis, Physicochemical Characterization, Biological Assessment, and Molecular Docking Study of Some Metal Complexes of Alloxan and Ninhydrin as Alterdentate Ligands

A series of transition metal complexes of alloxan monohydrate (H2L1) and ninhydrin (H2L2) have been prepared where metal ions are Fe(III), Co(II), Ni(II), Cu(II), Zr(IV), and Mo(VI). Different microanalytical techniques, spectroscopic methods, and magnetic studies were applied to assign the mode of bonding and elucidate the structure of complexes. All solid complexes are of 1:1 (M:L) stoichiometry and octahedral geometry except nickel (II) complexes exist in a tetrahedral geometry. FTIR spectral interpretation reveals that HL1 coordinates to the central metal ion in a bidentate ON pattern, whereas HL2 behaves as an alterdentate ligand through hydroxyl oxygen and carbonyl oxygen either C(1) = O or C(3) = O. The thermal behavior of some complexes was followed up to 700 °C by different techniques (TGA, DTA, and DSC) where decomposition stages progress in complicated mechanisms and are ended by the formation of metal oxide residue. Besides, biological screening involving antioxidant, antibacterial, and antifungal for ligands and some of their complexes was done. Moreover, four examined metal complexes displayed anticancer activity against hepatocellular carcinoma cells (HepG-2) but to different degrees. According to the IC50 values, Cu-ninhydrin complex, [Cu(HL2)(H2O)4].Cl has a better potency impact in comparison with cisplatin which was used as a reference control. This is in harmony with the molecular docking simulation outcomes that predicted a good binding propensity of the Cu-ninhydrin complex with hepatocellular carcinoma protein (2jrs). Therefore, the Cu-ninhydrin complex should be deemed as a potential chemotherapeutic agent for hepatocellular cancer.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10904-023-02661-5.

In situ thermal image analysis of selective laser sintering for oral dosage form manufacturing

Additive Manufacturing (AM) is a fast-growing approach to produce personalized oral dosage forms. Even though some AM technologies are promising as alternative to conventional compounding with resulting dosage manipulation, they still suffer from a lack of quality control. Due to the high regulatory demands and standards applied to dosage forms in the case of dose accuracy and tablet properties such as friability, effective quality control is a key feature in promoting AM as a valid technology for patient-tailored medications. One of the AM techniques used is selective laser sintering, which allows for capturing the surface state layer-by-layer during the printing process. It provides the opportunity to apply non-destructive quality control based on image analysis extracting essential data at each layer of the sintering process. This work is devoted to establishing the value of data gathered via thermal image analysis for the subsequent quality control.

Glass Formation in Hybrid Organic-Inorganic Perovskites

Crystalline materials have governed the development of hybrid organic-inorganic perovskites (HOIPs), giving rise to a variety of fascinating applications such as solar cells and optoelectronic devices. With increasing interest in non-crystalline systems, the glassy state of HOIPs has recently been identified. Here, the basic building blocks of crystalline HOIPs appear to be retained, though their glasses lack long-range periodic order. The emerging family of glasses formed from HOIPs exhibits diverse properties, complementary to their crystalline state. This mini review describes the chemical diversity of both three-dimensional and two-dimensional crystalline HOIPs and demonstrates how glasses are produced from these materials. Specifically, current achievements in melt-quenched glasses formed from HOIPs are highlighted. We conclude with our perspective on the future of this new family of materials.

Thermodynamic characterization of LF, H, and mineral soil layers from oak forest ecosystems: Exploring the role of proximate analysis

Studying the thermodynamic properties of soil organic matter is a developing field that involves the measurement of the energy stored by the soil. Quantifying soil energy content is still challenging despite different methodological approaches are available to calculate that value. One of the options is the proximate analysis following the guidelines for the energetic characterization of biomass. However, proximate analyses are still unexplored for soils. In this paper, we investigate the potential of this analysis to contribute to study soil from a thermodynamic perspective. With that goal, 31 soil samples collected in mature oak forests following a depth transect were used for elemental, thermal and proximate analysis. Proximate analyses and energetic characterization were performed by simultaneous thermogravimetry and differential scanning calorimetry. These methods allowed fragmentation of the soil organic matter in water content, volatile matter, fixed carbon, and ash, as well as the quantification of the soil organic matter and energy content. Pearson's correlation showed significant relations among the proximate, the elemental components of soils and the energy. The equations relating all of these variables were calculated for soils from oak forests by partial least squares analysis. Equations representing the relationship between energy and the proximate fractions provide an additional alternative to calculate the heat of combustion of the soil organic matter. This value is the essential step for the thermodynamic characterization of soils.

Polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly (AM-co-ECA-co-AMPS): Broadband dielectric spectroscopy investigations

In this study, the dielectric behavior of polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly(AM-co-ECA-co-AMPS) was investigated by broadband dielectric spectroscopy (BDS). The dielectric spectra obtained from -70 to 70 °C showed a superposition of three distinctive processes, electrode polarization, charge carrier's transport, and a molecular relaxation process. These dynamic processes were further analyzed along with the effect of both temperature and reduced graphene oxide (rGO) content. The development of a clear electrochemical double layer (ECDL) at the electrode/hydrogel interface strongly supports its possible application in supercapacitors' forms of energy storage. TGA, DSC, rheology, and electrochemical properties were studied. Furthermore, when the composite hydrogel with rGO content of 2.5 % was assembled into a symmetric supercapacitor, it displayed a specific capacitance of 756 F.g^-1 at 1 A.g^-1 and 704 F.g^-1 after 5000 cycles with high capacitance retention of 93.2 %. The superior conductivity and porous structure of the rGO composite hydrogel are credited with the hydrogel's excellent electrochemical capabilities.

Thermal analysis by variable temperature infrared spectroscopy with a button sample holder and Peltier heating/cooling

An apparatus and methodology for variable temperature infrared spectroscopy measurements of neat samples contained in a button sample holder are described. Sample heating and cooling are achieved by applying voltage to stacked Peltier thermoelectric devices. Between 0 and 150 °C, samples can be heated and cooled at 2 °C s^-1 rates, facilitating temperature step heating/cooling profiles with minimal delay between isothermal infrared spectrum measurements. Examples of correlating temperature-dependent spectral variations with specific sample changes are provided for α-quartz heating/cooling, ibuprofen melting, and acetylsalicylic acid thermal decomposition. Trends in α-quartz infrared spectra obtained with a step heating/cooling temperature profile are used to evaluate spectrum measurement reproducibility. Detection of vibration band intensity variations of less than 1% resulting from a 10 °C sample temperature increment illustrates the measurement sensitivity. By comparing infrared spectra obtained at different temperatures, reversible and irreversible sample changes are identified. Infrared spectra acquired during linear ramp heating are employed to determine the ibuprofen melting point, which confirms the temperature measurement accuracy of the apparatus. Selective analysis is demonstrated by determining isoconversion effective activation energies for processes involved in the thermal decomposition of the acetylsalicylic acid component of a commercial pharmaceutical tablet.

Evaluating the potential of hydrochar as a soil amendment

In this study, hydrochar (HC), a carbon-rich product originated from hydrothermal conversion treatment (HTC), was obtained from wastes of the wine and dairy industries. The effect of mixing secondary char and compost was tested, before and after the aerobic mixing of compost (COM) and HC at increasing doses (from 15 to 75 Mg ha^-1 DM), in an effort to lower the HC phytotoxicity due to potential phytotoxic compounds of secondary char. The results indicated that, after the aerobic stabilization, the mix HC/COM was able to double the plant growth in comparison to COM alone. The presence of easily degradable organic compounds probably led to poor stability of HC, increased microbial activity and, consequently, root anoxia when used at high doses. Chemical, spectroscopic and thermal investigation confirmed this hypothesis. In particular, HC shows a high content of dissolved organic matter, characterized by the presence of small molecules, which is negatively correlated with the growth index of lettuce. Furthermore, thermal characterization suggests a higher proportion of less complex and thermally stable molecular compounds in HC in comparison to COM. Therefore, co-composting of HC allows obtaining a useful amendment to support soil organic matter and fertility.

Exploring a new family of designer copper(II) complexes of anthracene-appended polyfunctional organic assembly displaying potential anticancer activity via cytochrome c mediated mitochondrial apoptotic pathway

The present article describes the systematic study on design and synthesis, physicochemical properties and spectroscopic features, and potential anticancer activities of a family of novel copper(II)-based designer metal complexes [Cu₂(acdp)(μ-Cl)(H₂O)₂] (1), [Cu₂(acdp)(μ-NO₃)(H₂O)₂] (2) and [Cu₂(acdp)(μ-O₂CCF₃)(H₂O)₂] (3) of anthracene-appended polyfunctional organic assembly, H₃acdp (H₃acdp = N,N'-bis[anthracene-2-ylmethyl]-N,N'-bis[carboxymethyl]-1,3-diaminopropan-2-ol). Synthesis of 1-3 was accomplished under facile experimental conditions, preserving their overall integrity in solution. The incorporation of polycyclic anthracene skeleton within the backbone of organic assembly increases lipophilicity of resulting complexes, thereby dictating the degree of cellular uptake with improved biological activity. Complexes 1-3 were characterized by elemental analysis, molar conductance, FTIR, UV-Vis absorption/fluorescence emission titration spectroscopy, PXRD and TGA/DTA studies, including DFT calculations. The cellular cytotoxicity of 1-3 when studied in HepG2 cancer cell line showed substantial cytotoxic effects, whereas no such cytotoxicity was observed when exposed to normal L6 skeletal muscle cell line. Thereafter, the signaling factors involved in the process of cytotoxicity in HepG2 cancer cells were investigated. Alteration of cytochrome c and Bcl-2 protein expression levels along with modulation of mitochondrial membrane potential (MMP) in the presence of 1-3, strongly suggested the possibility of activating mitochondria-mediated apoptotic pathway involved in halting the cancer cell propagation. However, when a comparative assessment on their bio-efficacies was made, 1 showed higher cytotoxicity, nuclear condensation, DNA binding and damage, ROS generation and lower rate of cell proliferation compared to 2 and 3 in HepG2 cell line, indicating that the anticancer activity of 1 is significantly higher than that of 2 and 3.

Characterization of eutectic mixtures of sugars and sugar-alcohols for cryopreservation

Natural Deep Eutectic Systems (NADES) composed of sugar and sugar alcohols have been studied and applied in a variety of biological applications. Understanding their interaction with water across dilution and temperature is inherently important for maximizing the utility of NADES. Herein a wide range of sugar:sugar-alcohol molar ratios were synthesized and characterized by viscosity, molar excess volume, differential scanning calorimetry, water activity, and confocal Raman cryomicroscopy. NADES were found to have greater viscosity, reduced heat of fusion, greater absolute molar excess volume, lower water activity, and stronger hydrogen bonding of water than non-NADES mixtures. This is hypothesized to be due to cumulatively stronger hydrogen bonding interactions between components in pure and diluted NADES with the strongest interactions in the water-rich region. This work provides useful data and further understanding of hydrogen bonding interaction strength for a wide range of molar ratios in pure to well-diluted forms.

Leverage of weave pattern and composite thickness on dynamic mechanical analysis, water absorption and flammability response of bamboo fabric/epoxy composites

Spar caps, which cover 50% of the cost of windmill blades, were made of unidirectional and biaxial glass/carbon reinforcements of 600 gsm with thicknesses ranging from 100 to 150 mm for blades 70-80 m long. The significance of this study was to utilize an economical biodegradable material i.e bamboo fabric of 125 gsm to fabricate a lightweight composite and study its behavior for spar caps applications. The aim of this research was to investigate the effect of weave pattern and composite size at coupon level under thermal, dynamic, water absorption, and flammability conditions. Composites comprising 125 gsm plain and twill weave bamboo as reinforcements/AI 1041 Phenalkamine bio-based hardener with epoxy B-11 as matrix were tested. Thermo-Gravimetric Analysis revealed that the weave pattern and composite thickness had an effect on the rate of weight loss and sustenance until 450 °C. The pattern had an effect on the glass transition temperature, as seen by Differential Scanning Calorimetry. The weave pattern and size thickness had an effect on energy storage and dissipation, displaying the damping behavior in DMA. The weave pattern and size had an effect on the rate of water absorption, which saturated after a few hours. The wettability and thickness of composites hampered the burning rate, with 5.4 mm thickness resulting in a 30% decrease.

Thermal finite element analysis of localized hypothermia treatment of the human eye

Localized hypothermia treatment can reduce the risk of vision loss due to ocular trauma. Hypothermia reduces inflammation and metabolic rate, and improves blood flow to prevent nerve and tissue damage. This paper presents a finite element thermal analysis to determine the efficacy of local hypothermia treatment administered using a scleral eye contact ring that acts as a heat sink. A realistic model of the human eye orbit, including fat and muscle, is created using MRI scans. A simplified CAD-based model is also created based on the first model. A transient analysis is performed by lowering the contact surface between the device and the eye to 4^∘C. The study shows that the device lowers the temperature of the optic nerve head to a therapeutic range of 32-34^∘C in less than 10 min of treatment, hence supporting the efficacy of such a device.

Preparation and Physiochemical Analysis of Novel Ciprofloxacin / Dicarboxylic Acid Salts

The crystal structures of four novel dicarboxylic acid salts of ciprofloxacin (CFX) with modified physicochemical properties, prepared by mechanochemical synthesis and solvent crystallization, are reported. A series of dicarboxylic acids of increasing molecular weight was chosen, predicted to interact via a carboxylic acid:secondary amine synthon. These were succinic (SA), glutaric (GA), adipic (AA) and pimelic (PA) acids (4, 5, 6, 7 carbon atoms respectively). Characterized by single crystal and powder X-ray diffraction, Fourier-Transform Infrared Spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and aqueous solubility measurements, these salts showed distinct physicochemical properties relative to ciprofloxacin base. Searches of the Cambridge Structural Database (CSD) confirmed CFX-SA, CFX-GA, CFX-AA and CFX-PA to be novel crystal structures. Furthermore, the GA salt has substantially higher solubility than the widely available hydrochloride monohydrate salt (CFX-HCl·H₂O). CFX-SA, CFX-GA and CFX-AA showed minimum inhibitory concentration (MIC) of 0.008 g/L and CFX-PA showed MIC of 0.004 g/L. The prepared CFX salts retained antibacterial activity exhibiting equivalent antimicrobial activity to CFX-HCl·H₂O. These salts have positive implications for increasing the application of CFX beyond conventional oral formulations and highlight mechanochemical activation as suitable production method.

Investigating and Comparing the Applicability of the R3m Molecular Descriptor and Solubility Parameter Estimation Approaches in Predicting Dispersion Formation Potential of APIs in a Random Co-Polymer Polyvinylpyrrolidone Vinyl Acetate and its Homopolymer

Evaluation of different amorphous solid dispersion carrier matrices is enabled by active pharmaceutical ingredient (API) structure-based predictions. This study compares the utility of Hansen Solubility Parameters with the R3m molecular descriptor for identifying dispersion polymers based on the structure of the drug molecule. Twelve API-polymer combinations (4 APIs and 3 interrelated polymers) were used to test each approach. Co-solidified mixtures containing 75% API were prepared by melt-quenching. Phase behavior was evaluated and classified using differential scanning calorimetry, powder X-ray diffraction, polarized light microscopy, and hot stage microscopy. Observations of dispersion behavior were compared to predictions made using the Hansen Solubility Parameter and R3m. The solubility parameter approach misclassified the dispersion behavior of 1 API-polymer combination and also did not produce definite predictions in 3 out of 12 of the API-polymer combinations. In contrast, R3m classifications of dispersion behavior were correct in all but two cases, with one misclassification and one ambiguous prediction. The solubility parameters best classify dispersion behavior when specific drug-polymer intermolecular interactions are present, but may be less useful otherwise. Ultimately, these two methods are most effectively used together, as they are based on distinct features of the same molecular structure.

Incinerator ash characterization - Implications for elevated temperature landfills

The occurrence of temperatures in municipal solid waste (MSW) landfills in excess of 55 °C is a problem that has gained much attention in the solid waste industry, both domestically and globally. Facilities which frequently experience such temperatures are termed Elevated Temperature Landfills (ETLFs). Ash, both MSW incinerator ash (MSWIA) and coal combustion ash (CCA), when co-disposed with unburned MSW, can provide constituents which are able to partake in abiotic exothermic reactions that may develop or sustain elevated temperatures. These reactions include hydration and carbonation, as well as the oxidation and corrosion of metals commonly found in ash. In this study, sixteen ash samples from across the U.S. were characterized by using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy (SEM/XEDS) to identify complex mineral and glassy phases enriched in calcium, silicon, aluminum, and iron. The high-temperature incineration of MSW and coal feedstocks, along with weathering processes impacting these ashes, yield a heterogenous material capable of generating appreciable heat given the right conditions. Additionally, a simple model was developed and, using ash compositions obtained via XEDS, a value termed relative heat potential (RHP) was estimated for each sample. Results show that CCAs may be expected to generate roughly 15 % more heat than MSWIAs when deposited in landfills due to their greater aluminum content.

Analysis of samples of high explosives extracted from explosive remnants of war

Millions of tonnes of dumped ammunition and explosive remnants of war remain in nature both on land and at sea. It is well known that the ordnance could represent a definite explosive risk if disturbed, and that some of the constituents in the ammunition could be harmful to humans and the environment. Nevertheless, a tacit assumption by decision makers is that, if left alone, the ammunition will slowly become harmless over time. Explosive remnants of war, however, represent not only an environmental risk but also a security and safety risk, as members of the public could come into contact with them, and fear is growing that ageing munitions could explode and/or be misused. In recent years, several concerns have been raised regarding the presence of dumped ammunition and explosive remnants of war, the potential dangers they represent, and the fact that the deterioration rate of the explosives could be significantly lower than previously assumed. In the present work, thermal and impact sensitivity studies of high explosives extracted from explosive remnants of war were performed, to determine whether or not the explosives have deteriorated to such a degree that a noteworthy decrease in performance and/or impact sensitivity can be recorded. The thermal behaviour of the explosives was studied using thermogravimetry analysis, and the impact sensitivity was determined using a fallhammer machine and the Bruceton test procedure. The thermal and impact sensitivity results obtained in the analysis indicated no deterioration of high explosives in the examined explosive remnants of war that would denote any significant reduction in performance and/or impact sensitivity.

Formulation of dry powders of vaccines containing MF59 or AddaVax by Thin-Film Freeze-Drying: Towards a dry powder universal flu vaccine

MF59® is an oil-in-water (O/W) nanoemulsion-based vaccine adjuvant that is often used in seasonal and pandemic influenza vaccines. We explored the feasibility of developing dry powders of vaccines adjuvanted with MF59 or AddaVax™, a preclinical grade equivalent of MF59 with the same composition and droplet size as MF59, by thin-film freeze-drying (TFFD). Liquid AddaVax alone was successfully converted to a dry powder by TFFD using trehalose as a stabilizing agent while maintaining the droplet size distribution of AddaVax after it was reconstituted. TFFD was then applied to convert liquid AddaVax-adjuvanted vaccines containing either a model antigen (e.g., ovalbumin) or mono-, bi-, and tri-valent recombinant hemagglutinin (rHA) protein-based H1 and/or H3 (universal) influenza vaccine candidates, as well as the MF59-containing Fluad® Quadrivalent influenza vaccine to dry powders. Both antigens and stabilizing agents affected the physical properties of the vaccines (e.g., mean particle size and particle size distribution) after the vaccines were subjected to TFFD. Importantly, the integrity and hemagglutination activity of the rHA antigens did not significantly change and the immunogenicity of reconstituted influenza vaccine candidates was maintained when evaluated in a mouse model. The vaccine dry powder was not sensitive to repeated freezing-and-thawing, in contrast to its liquid counterpart. It is concluded that TFFD can be applied to convert liquid vaccines containing MF59 or AddaVax to dry powders while maintaining the immunogenicity of the vaccines. Ultimately, TFFD technology may be used to prepare dry powders of multivalent universal influenza vaccines.

Effects of technosols based on organic amendments addition for the recovery of the functionality of degraded quarry soils under semiarid Mediterranean climate: A field study

This study aims to evaluate the effects of technosols made with different organic amendments to restore degraded soils in a semiarid limestone quarry. The effects on soil quality, functionality and organic matter dynamics of the technosols amended with waste of gardening, greenhouse horticultural, stabilized sewage sludge and two mixtures of sludge with both vegetable composts were assessed. Several physical and chemical properties, humus fractions, soil respiration and molecular composition was performed after 6 and 18 months. Un-amended soils, and nearby natural undegraded soils served as reference. Amended technosols increased water retention capacity, electrical conductivity, total organic carbon and nitrogen, respect to not amended and natural soils. Humus fraction composition was not altered over time. Un-amended soils, very poor in organic matter, did not show any pyrolyzable compounds or labile soil organic matter by thermogravimetry. In contrast, the pyrochromatograms of natural soils showed lignocellulosic materials, polypeptides and a noticeable presence of alkylic compounds. In technosols with both types vegetable compost, the organic matter structure was more complex, showing compounds from lignin-derived and long-chain alkyl, polysaccharides, chlorophyll isoprenoids and nitrogen. In sludge technosol, a set of sterols was outstanding. The mixtures showed a molecular fingerprint of materials derived from the decomposition of the organic amendments that formed them. These signs of the contribution of different organic matter forms derived from the amendments were also reported by the series exothermic peaks found in the calorimetry. This short-term study indicates a clear effect of the amendments on the recovery of soil organic matter and presumably of its functionality. After the amendments application, microbial activity and soil respiration rates increased rapidly but ceased 18 months later. The molecular composition of the organic matter of the soils amended with plant compost was very similar to that of natural, non-degraded soils in nearby areas.

Evaluation of the thermal stability of bioactive compounds in coffee beans and their fractions modified in the roasting process

Coffee is used as flavor or health-promoting additive in thermally processed food. In this study, ground coffee and freeze-dried coffee extracts were evaluated in terms of their thermal stabilities, and for the first time heat resistance of fractions (mono-, dichlorogenic acids and caffeine) with different roasting levels was evaluated. It observed that the degradation of green coffee bean ingredients began at 150 °C, and for the re-heated light and dark roasted, in the range of 171-188 °C. The lyophilized extracts were more stable and their degradation began around 160 °C. However, with the re-treatment (cooking, baking, frying) of the coffee extract fractions, the degradation of the monochlorogenic acids commenced at 114 °C, while for dichlorogenics at 108 °C and caffeine at 146 °C. Monochlorogenic acids in Robusta coffee showed high antioxidant activity (55-70%) and the highest content of fiber (13-17%). Coffee could be used to fortify food.

A Dual Approach on Experimental, Theoretical Insight of Structural Elucidation, Hirshfeld Surface Analysis, Optical and Electrochemical Properties of Acyl Thiourea-Ethynyl Hybrid Derivatives

Hybrid moieties of ethynylated-thiourea, Th1 and Th2 have been synthesised via the addition reaction between ethynyl derivatives and 4-tert-butylbenzoyl isothiocyanate in acetone, and were characterised by selected spectroscopic methods (i.e., ¹H and ¹³C NMR, UV-visible, FT-IR) and elemental analysis. Thermogravimetric analysis indicated that Th1 and Th2 were relatively stable up to ca. 210 °C. Single-crystal X-ray diffraction was used to identify the crystal structure of Th2 in which the centre of 1-acyl thiourea moiety (-C(O)NHC(S)NH) exhibits S conformation. The Hirshfeld surface analysis has allowed visualizing the crystal packing, which is characterised by the prolonged intermolecular N-H⋯O = C and N-H⋯S = C hydrogen-bonding interactions within Th2 molecule. Electrochemical data of both compounds correspondingly exhibit irreversible redox potential processes. Besides, frontier molecular orbitals and Natural Bond Orbital population analysis were computed at the B3LYP/6-31G (d, p) level of approximation, suggesting strong delocalization of the electronic density through a conjugated π-system involving the ethynyl-phenyl and thiourea groups.

GRAPHICAL ABSTRACT

Figure of molecular structure for acyl thiourea-ethynyl derivative. Two derivatives of acyl thiourea-ethynyl were synthesised and characterised by selected spectroscopic methods such as 1H and 13C NMR, UV-visible, FT-IR, elemental, thermal, electrochemical, X-ray diffraction, and density functional theory (DFT) calculation for molecular orbitals and natural bond orbital population analysis.

Thermodynamic properties, decomposition kinetics of 2-(5-amino-2H-tetrazol-1-yl)-4-amine-3,5-dinitropyridine

A novel energetic material 2-(5-amino-2H-tetrazol-1-yl)-4-amine-3,5-dinitropyridine (ATDP) was synthesized and characterized by ¹H NMR, ¹³C NMR, mass spectroscopy, and elemental analysis. The research by differential scanning calorimetry (DSC) shows that ATDP decomposed about 290 °C. The calculating results of kinetic parameters using Ozawa method, Kissinger method, and Starink method were quite consistent. Self-accelerated decomposition temperature (T_SADT), thermal ignition temperature (T_TIT), and critical temperature of thermal explosion (T_b) were 272.55 °C, 121.71 °C, and 137.67 °C, respectively. Geometric optimization, heat of formation, detonation velocity (D), detonation pressure (P), bond dissociation energy (BDE), and electrostatic potential (ESP) were explored using Gaussian 16. The results show that ATDP has a much larger ΔH_f,gas value than HMX(272.6 kJ mol^-1). The D and P are predicted with the value of 7.50 km s^-1 and 24.47 GPa, respectively. The relatively high BDE value (270.77 kJ mol^-1) indicates that ATDP has moderate thermal stability.

Preformulation and characterization of raloxifene-loaded lipid nanoparticles for transdermal administration

Transdermal administration of raloxifene hydrochloride (RLX)-loaded nanostructured lipid carriers (NLCs) has been proposed to circumvent its low oral bioavailability (2%). Preformulation studies were carried out to evaluate drug-excipient compatibility of various adjuvants commonly used for NLC preparation (waxes, cholesterol, compritol, gelucire, span 60, span 80, span 85, tween 80, poloxamer 188, oleic acid, caprylic/capric triglyceride, and castor oil). It was used differential scanning calorimetry (DSC), isothermal stress testing (IST), and solubility studies. The most promising excipients were chosen for NLC obtention, and full characterization was done, including in vitro skin permeation. DSC curves suggested drug-excipient interaction among some compounds, and the IST study showed incompatibility of RLX with waxes, compritol, cholesterol, span 60, and poloxamer 188. Solubility studies helped select gelucire, caprylic/capric triglyceride, span 80, and tween 80 for NLC production. Twelve NLCs were obtained (NLC1 to NLC12), but NLC7 and NLC8 were the most promising ones. In vitro release studies demonstrated that NLC7 and NLC8 were able to control RLX release (14.74 and 9.07% at 24 h, respectively) compared with the unloaded drug (> 90% at 24 h). Unloaded RLX did not permeate the diffusion cells' receptor medium and showed higher drug skin retention (11-fold) than RLX-loaded NLC. NLC reduced RLX skin retention, favoring drug permeation to deeper skin layers. NLC7 increased drug flux is 2.4-fold. NLC7 is a promising formulation for RLX transdermal drug delivery.

Synergistic effects of ultrasonic irradiation and α-Fe2O3 nanoparticles on the viscosity and thermal properties of an asphaltenic crude oil and their application to in-situ combustion EOR

In this work, the effects of ultrasonic irradiation assisted by α-Fe₂O₃ nanoparticles (NPs) on the evolution of viscosity and thermal properties of crude oil are evaluated. A viscous crude oil with a high amount of asphaltene (∼20% by mass) was used for ultrasonication over different exposure times and nanoparticle concentrations. The viscosity of the oil before and after ultrasonic irradiation was measured with and without nanoparticles. Experimental results indicated that the viscosity of irradiated oil containing nanoparticles at optimum conditions was lower than the viscosity of nanoparticle-free irradiated oil. The thermal behavior of the irradiated crude oil mixed with nanoparticles at optimum conditions was examined using the TGA/DTA methods. The results showed a non-complementary effect of ultrasonic irradiation and nanoparticles on the weight loss and the amount of residual oil at both the end of the pyrolysis and oxidation stages, representing that addition of the α-Fe₂O₃ NPs to the crude oil and the ultrasonication of the crude oil work in the opposite direction. Based on the TG/DTA data, the kinetic parameters of the pyrolysis and oxidation reactions were estimated. It was found that the simultaneous use of ultrasonic irradiation and nanoparticles sharply decreased the activation energy of the oxidation reactions, but had almost no effect on the activation energy of the pyrolysis reactions. The results of this paper provide an insight into the effectiveness of in-situ combustion enhanced oil recovery, which depends on viscosity reduction and the rate at which heat is generated.