Miracle-dz/UniFAR-FTUs huggingface dataset:
Constituents of the seeds of Swietenia mahagoni JACQ. III. Structures of mahonin and secomahoganin.

Two new tetranortriterpenoids, mahonin and secomahoganin, have been isolated from the cotyledons of seeds of Swietenia mahagoni. The structures of these compounds were determined by the use of two-dimensional nuclear magnetic resonance (2-D NMR) techniques (1H-1H correlation spectroscopy (COSY), 1H-13C COSY, and 1H-13C long-range COSY) and assignments of their 1H-and 13C-NMR signals were performed. A possible biosynthetic pathway to these tetranortriterpenoids is proposed.
Trioctahedral entities in palygorskite: Near-infrared evidence for sepiolite-palygorskite polysomatism

The mixed dioctahedral-trioctahedral character of Mg-rich palygorskite has been previously described by the formula yMg5 Si8 O20(OH)2(OH2)4(1–y)[xMg2Fe2(1–x)Mg2 Al2] Si8 O20(OH)2(OH2)4, where y is the trioctahedral fraction of this two-chain ribbon mineral with an experimentally determined upper limit of y 0.5 and x is the FeIII content in the M2 sites of the dioctahedral component. Ideal trioctahedral (y ¼ 1) palygorskite is elusive, although sepiolite Mg8Si12O30(OH)4(OH2)4 with a similar composition, three-chain ribbon structure and distinct XRD pattern is common. A set of 22 samples identified by XRD as palygorskite and with variable composition (0 , x , 0.7, 0 , y , 0.5) were studied to extrapolate the structure of an ideal trioctahedral (y ¼ 1) palygorskite and to compare this structure to sepiolite. Near-infrared spectroscopy was used to study the influence of octahedral composition on the structure of the TOT ribbons, H2O in the tunnels and surface silanols of palygorskite, as well as their response to loss of zeolitic H2O. All spectroscopic evidence suggests that palygorskite consists of discrete dioctahedral and trioctahedral entities. The dioctahedral entities have variable structure determined solely by x=FeIII/(Al+FeIII) and their content is proportional to (1–y). In contrast, the trioctahedral entities have fixed octahedral composition or ribbon structure and are spectroscopically identical to sepiolite. The value of d200 in palygorskite follows the regression d200 (A°)= 6.362 + 0.129 x(1–y) + 0.305y, R2 = 0.96, σ = 0.013A°. When extrapolated to y = 1,d200 is identical to sepiolite. Based on this analysis, we propose that palygorskite samples with non-zero trioctahedral character should be considered as members of a polysomatic series of sepiolite and (dioctahedral) palygorskite described by the new formula y'Mg8 Si12 O30(OH)4(OH2)4. (1–y')[x'Mg2Fe2(1–x')Mg2Al2]Si8O20(OH)2(OH2)4, with 0 < x'= x < 0.7 and 0 < y' = y/(2–y) < 0.33.
Resonances in the O(3P)+HCl reaction due to van der Waals minima

We present extensive exact quantum calculations of the cumulative reaction probability (CRP) for the O(3P)+HCl→OH+Cl reaction for a large range of total angular momentum, using the most recent ab initio potential energy surface of Ramachandran et al. This surface contains van der Waals minima in both the entrance and exit channels that are shown to be responsible for a number of prominent resonances in the CRP in the tunneling region. The evidence for this claim is based on an analysis of the quasibound states of the van der Waals minima and a simple overlap of these states with the region of the saddle point of the reaction. The shift of the CRP with total angular momentum is analyzed in detail, with a focus on the resonances. A rigorous test of the simple J–K shifting approximation is also made both for the total CRP and the thermal rate constant.
Behavior of an organic solvent drop during the supercritical extraction of emulsions

The behavior of a drop of dichloromethane in water in contact with CO2 at high pressure has been investigated with the purpose of analyzing the phenomena that takes place during the supercritical fluid extraction of emulsions process. Experiments have been performed with and without a solute (β-carotene) and a surfactant (n-octenylsuccinic anhydride-modified starch) dissolved in the drop, and the evolution of the drop volume as well as of the interfacial tension between the drop and the aqueous phase has been measured. Additionally, a mathematical model has been developed that allows describing the mass transfer. Results show that the drop undergoes swelling and shrinking processes due to diffusion of CO2 into the drop and dichloromethane out of the drop. CO2 concentration in the drop can be as high as 0.9 (molar fraction). Emulsion drops behave as miniature gas antisolvent precipitators and many particles are formed inside the drop. The interfacial tension between the drop and the aqueous phase increases during the process, therefore destabilizing the emulsion. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Synthesis of a novel and stable g-C3N4–Ag3PO4 hybrid nanocomposite photocatalyst and study of the photocatalytic activity under visible light irradiation

A facile and reproducible template free in situ precipitation method has been developed for the synthesis of Ag3PO4 nanoparticles on the surface of a g-C3N4 photocatalyst at room temperature. The g-C3N4–Ag3PO4 organic–inorganic hybrid nanocomposite photocatalysts were characterized by various techniques. TEM results show the in situ growth of finely distributed Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The optimum photocatalytic activity of g-C3N4–Ag3PO4 at 25 wt% of g-C3N4 under visible light is almost 5 and 3.5 times higher than pure g-C3N4 and Ag3PO4 respectively. More attractively, the stability of Ag3PO4 was improved due to the in situ deposition of Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The improved performance of the g-C3N4–Ag3PO4 hybrid nanocomposite photocatalysts under visible light irradiation was induced by a synergistic effect, including high charge separation efficiency of the photoinduced electron–hole pair, the smaller particle size, relatively high surface area and the energy band structure. Interestingly, the heterostructured g-C3N4–Ag3PO4 nanocomposite significantly reduces the use of the noble metal silver, thereby effectively reducing the cost of the Ag3PO4 based photocatalyst.
Factors Affecting the Use of Online Recommendation Systems in E-Commerce in Croatia

The concept of utilizing IT for recommendations has existed since the inception of computer science, but it has become more prevalent in recent years as e-commerce has grown significantly. Because recommendation systems are effective at simulating customer behaviour and offering users personalisation, they have helped numerous e-commerce and content providers expand. In order to determine what influences customers’ adoption and usage of online purchase recommendation systems, this research explores the factors affecting recommendation systems’ adoption and use in e-commerce in Croatia. The structural model of partial least squares and the Unified Theory of Adoption and Use of Technology (UTAUT) were employed to accomplish this goal (PLS). 130 users of online recommendation systems made up the sample. Research has shown that users will only utilize recommendations if they are given supplementary goods that improve their purchasing experience. Users trust recommendation systems (43%), but they have reservations about whether they deliver on their promises which is related to the fact that only a small number of retailers track and evaluate the effectiveness of recommendation systems in their online stores.
Density, structural lifetime, and entropy of H‐bond cages promoted by monohydric alcohols in normal and supercooled water

Density data for aqueous solutions of monohydric alcohols down to supercooling are presented and combined with data concerning viscosity of the same systems, and with available data on pure water. Two conceptually different families of longer‐lived, high‐connectivity H‐bond structures can be sorted out in the irregular, frequently restructured network of H bonds: spontaneous structures, as in pure water, and alcohol‐induced structures. Molar volumes for both are obtained and compared, allowing microscopic conclusions which agree quantitatively with available thermodynamic data. For the three alcohols studied, the well‐known negative excess entropy of mixing shows a strict proportionality to the fraction of water molecules sorted out in our study as taking statistically part in alcohol‐promoted cages. The remarkable proportionality extends to all alcohols, all concentrations, and all temperatures studied. Apparent (and expected) geometric distortions of alcohol‐promoted cages do not affect this proportiona.
Cardioprotective effects of selenium and morin hydrate in a murine model of chronic iron overload

Iron overload cardiomyopathy is the most prevalent cause of death due to heart failure in young patients in their second and third decades of life. Although the exact mechanism for heart failure is not known, it is hypothesized that a disordered redox balance, such as in selenium deficiency, ultimately leads to free radical mediated damage in a variety of disorders including hemochromatosis. We report here on the effects of selenium and morin hydrate on heart tissue concentrations of iron, glutathione peroxidase activity, and the production of 20 separate aldehyde-derived peroxidation products, in a murine model of chronic iron overload. Sixty B6D2F1 mice were randomized to one of the following four treatment groups for a total period of 4 weeks: (1) control (normal saline, 0.5 ml i.p./ mouse / day); (2) iron-only (iron-dextran, 10 mg i.p. / mouse / day); (3) selenium (sodium selenite, 0.5 ppm orally) and iron, and (4) morin hydrate (0.15 mg i.p./ mouse / day) and iron. Our findings show that supplementation with selenium (sodium selenite) or morin hydrate can decrease, in comparison to iron-only treated groups, both the concentrations of total iron and cytotoxic aldehydes in heart tissue, despite concurrent chronic iron loading in a murine model. Iron and selenium supplemented mice also had significant increases in heart glutathione peroxidase activity, in comparison to iron-only treated mice. This is the first description on the effects of selenium and morin hydrate on the concentrations of iron and cytotoxic aldehydes in heart tissue of a murine model of chronic iron overload. J. Trace Elem. Exp. Med. 13:285–297, 2000. © 2000 Wiley-Liss, Inc.
Surface Tension of Seawater

New measurements and a reference correlation for the surface tension of seawater at atmospheric pressure are presented in this paper. Surface tension of seawater was measured across a salinity range of 20 ⩽ S ⩽ 131 g/kg and a temperature range of 1 ⩽ t ⩽ 92 °C at atmospheric pressure using the Wilhelmy plate method. The uncertainty within measurements varied from 0.18 to 0.37 mN/m with the average uncertainty being 0.22 mN/m. The experimental procedures were validated with tests conducted on ACS reagent grade water and aqueous sodium chloride solutions. Literature data and present measurements were evaluated and a reference correlation was developed expressing surface tension of seawater as a function of temperature and salinity. The average absolute percentage deviation between measurements and the correlation was 0.19% while the maximum deviation was 0.60%.
Gas phase ion chemistry of HNO3

The ion chemistry of HNO3 is studied at 298 °K. The attachment of thermal electrons to HNO3 to produce NO−2 is found to have a rate constant of (5±3) ×10−8 cm3/sec. HNO3 reacts rapidly (k∼10−9 cm3/sec) with a large variety of negative ions including Cl−, NO2−, O2−, and CO−3. HNO3 is also found to bond strongly to NO3−. The proton affinity of HNO3 is determined to be 176±7 kcal/mole. The present results indicate a strong similarity between protonated HNO3 and hydrated NO2+, suggesting that these ion species are identical. The implication of the present results for atomospheric ion chemistry is discussed.
DNA minor groove alkylating agents structurally related to distamycin A

Analogues of naturally occurring antitumour agents, such us distamycin A, which bind in the minor groove of DNA, represent a new class of antineoplastic compounds currently under investigation. Distamycin Ahas attracted researchers’ attention not only for its biological activity, but also for its non-intercalative binding to the minor groove of double-stranded B-DNA, where it forms a strong reversible complex preferentially at the nucleotide sequences consisting of 4 - 5 adjacent AT base pairs. Distamycin has also been used as a DNA sequence-selective vehicle for the delivery of alkylating functions to DNA targets, leading to a sharp increase in cytotoxicity, in comparison to that of distamycin alone. In the last few years, several hybrid compounds, in which known antitumour derivatives or simple active moieties of known antitumour agents have been tethered to distamycin frames, have been designed, synthesised and tested. Several efforts have been made to modify the DNA sequence selectivity and stability of distamycin; structural modifications have been based on replacement of pyrrole by other heterocycles and/or benzoheterocycles resulting in a novel class of minor groove binding molecules called lexitropsins. The role of the amidino moiety has also been studied by substitution with various groups, including ionisable, acid or basic and non-ionisable groups. The synthesis of a hybrid derived from combining distamycin A and a naturally occurring alkylating agent structurally related to pyrrolo [2,1-c][1,4] benzodiazepine group, such as anthramycin and DC-81, has been also reported. Several classes of distamycin derivatives that have been reported in the published literature and in recent patent fillings have been described in this review article.
Effect of unfavorable continuous phase density gradient on axial mixing

Field experience with several industrial reciprocating plate liquid-liquid extraction columns indicated that large density gradients in the continuous phase resulted in excessive backmixing. Since there are no published data on the effect of higher density in the upper section compared to lower density in the bottom section of the column, experiments were performed with the calcium chloride brine-water system in a 76.2 mm diameter reciprocating plate column. Axial dispersion coefficients, E, were found to be 10–20 times higher than the values in systems with uniform densities. E decreased with increasing agitation to 30% of the value with no agitation. The effect of increasing flow rate of water up the column was to increase both E and the Peclet number. E was correlated with the density difference between any point in the column and tap water. Another correlation was obtained showing the effects of buoyant and mechanical energy input on axial dispersion.
Using De Novo Metagenome Assembly for Improved Metagenomic Classification

Metagenomics is a rapidly growing field that allows for studying complex microbial communities. One of the first steps in the metagenomic analysis is the classification of the organisms present in a sample. This is usually done by comparing sequencing reads to a database of known organisms. With the recent development of long-read sequencing technologies, such as PacBio and Oxford Nanopore Technologies (ONT), it is now possible to generate highly accurate assemblies of genomes from metagenomic samples. This is typically done using a combination of reference-based and de novo assembly approaches. Assembling the genomes from the metagenomic sample, prior to classification, could improve classification results and also aid in identifying new, previously unknown species. However, the evaluation of metagenome assemblies is a challenging task and it is important to assess the quality of the assemblies in order to ensure the accuracy of downstream analyses. In this paper, we provide a detailed overview of metagenomic classification, de novo metagenome assembly process, and evaluation of metagenome assembly, highlighting various tools and techniques currently available for each step. We also present initial results showing that metagenomic classification can benefit from a previously assembled metagenome.
Muscle Quality and Proteolytic Enzymes of Farmed Atlantic Cod (Gadus morhua) During Storage: Effects of Pre-Slaughter Handling and Increased Storage Temperature

ABSTRACT In the present experiment, the characteristics of minimally handled, directly slaughtered farmed Atlantic cod were compared to cod subjected to 2 h preslaughter handling stress. The results strongly indicate that increasing the storage temperature from 0 to 5°C had a larger negative impact on the quality characteristics than the handling stress applied. Further, there may be interaction effects between handling, storage temperature, and storage time.
The effect of osmosis pretreatment on hot-air drying and microwave drying characteristics of chili (Capsicum annuum L.) flesh

Summary Chili flesh pretreated with or without osmotic dehydration (OD) was dried in the hot-air drying (AD) oven at 50–80 °C or in the microwave drying (MD) oven at 60–180 W. Results showed that the samples osmotically treated in mixed solution (10% salt + 50% sucrose) had the best dehydration effect as compared with single salt or sugar solutions. During the drying process, osmotically treated samples had one falling-rate period and their effective moisture diffusivities (Deff) showed a rapidly linear increase with the decrease in moisture content, while directly drying samples showed a three-phase falling-rate period and their Deff increased gradually at the initial period and then rapidly at the final period. When the moisture content decreased, the activation energy increased gradually; however, for AD after OD, it decreased. Among all the processes, MD at 60 W after OD presented the largest vitamin C retention rate and the best colour difference, needing less drying time.
Analysis of Giant Pumpkin (Cucurbita maxima) Quality Parameters in Various Technologies of Convective Drying After Long-Term Storage

The research involved the analysis of the quality of “Justynka” variety pumpkin, dried at temperatures from 40°C to 80°C, after long-term storage. The quality of dried pumpkin was assessed based on the content of total and reducing sugar, lutein, lycopene, and β-carotene. Tests were conducted to determine the content of these substances in the samples dried with different methods; i.e., in natural and forced convection in the tunnel dryer, with the drying agent speed of 1.2 m/s, and with the two-stage method. It has been concluded that the quality of the product depends on drying time and air flow.
THEORETICAL INVESTIGATION ON ENERGY GAP OF FLUORENE-THIOPHENE COPOLYMER

In this work, HOMO-LUMO energy gap and the lowest excitation energy of poly [2,7-(9,9-dihexylfluorene)-co-alt-2,5-(decylthiophene) were performed by different methods. The obtained results indicate that TDDFT(B3LYP/6-31G*)//B3LYP/6-31G* calculations can be useful to provide reliable energetic and structural results of this polymer. The HOMO-LUMO predictions were not accurately obtained as compared to the experimental results. The inverse chain length approximation by using TDDFT(B3LYP/6-31G*)//B3LYP/6-31G* calculations provides energy gap of 2.50 eV, which is in an excellent agreement with the experimental data. However, it was found that the HOMO-LUMO energy gaps obtained from B3LYP calculations were still far from the experimental data.
Combinative Application of pH-Zone-Refining Counter-Current Chromatography and Preparative HPLC for the Separation of Alkaloids From Lycoris radiata

The bulb of Lycoris radiata as a traditional folk medicine is well known for its biological activities and has been used for the treatment of many diseases. The major chemical ingredients of this herb are alkaloids including lycoramine, galantamine, and so on. In order to further articulate the pharmacological activities of the herb, relatively purified alkaloids are needed. Therefore, a rapid and efficient method for the isolation and purification of these alkaloids from the bulb of Lycoris radiata is of great interest. We herein report a new technique pH-zone-refining counter-current chromatography (CCC) combined with preparative high-performance liquid chromatography (HPLC) for the isolation and purification of these active ingredients. Although the conventional high-speed HSCCC method for the successful separation of the alkaloids from Lycoris radiata has been reported, only two alkaloids are obtained. In the present study, seven alkaloids all with a purity of over 95% are successfully separated using this combinative technique. And the sample loading capacity is increased by 150-fold compared with that mentioned in the literature. Therefore, the combinative application of pH-zone-refining CCC and preparative HPLC is a rapid and efficient method for the separation and purification of natural compounds.
Total and Extractable Heavy Metals in Indoor, Outdoor and Street Dust from Aswan City, Egypt

The level of heavy metal contamination in indoor room dust is evaluated and its relationship to the external environment examined. Samples of outdoor fallen dust, indoor room dust and street dust were collected from two different environmental locations in Aswan city, Egypt. Total and extractable (soluble) concentrations of cadmium, lead, iron, and manganese were determined in the three types of dust samples. The measurements of the metal contents were preformed using atomic absorption spectroscopy. The aims of this study are: (a) to assess the influence of urban traffic on the heavy metal content in house and street dust, and (b) to determine and compare the soluble fractions of the metals in indoor house dust, outdoor fallen dust and street dust. The results showed widespread heavy metal contamination, especially Pb, Mn, and Fe, which were present as the highest values in the outdoor fallen dust, indoor and street dust, while Cd was the lowest content metal present. In general, indoor and outdoor concentration ratios varied widely from one metal to another and from one residence to another. An enrichment factor for metal explained the originality of these metals. Traffic near the two studied buildings reflects the presence of Pb in outdoor fallen dust, indoor room dust and street dust in those residences. Soluble fractions of the studied heavy metals seem to be at the lower values compared to total metal concentration present.
Light emitting diodes increase phenolics of buckwheat (Fagopyrum esculentum) sprouts

Abstract Four types of light emitting diodes (LEDs) were used in three combinations (all blue [BBB], red: blue: far-red [RBFr]=4:1:1 and red: green: blue [RGB]=4:1:1) and seven irradiation cycles (12 h/12 h photoperiod, 1 Hz, 10 Hz, 100 Hz, 1 KHz, 10 KHz and 100 KHz) were applied to examine their effect on growth, stem color and phenolic compounds (homoorientin, orientin, rutin, vitexin and isovitexin) in buckwheat (Fagopyrum esculentum cv. Great Ruby) sprouts. With a few exceptions, among all the combinations and irradiation cycles of LEDs, the Great Ruby cultivar showed significant differences in total height and dry weight of sprouts. The study revealed that there was a direct effect of different combination and irradiation cycles of LEDs on sprout height and dry weight; and among the combinations, RBFr and BBB had more positive effect than RGB. Increasing irradiation cycles markedly decreased the red color of stalks of F. esculentum cv. Great Ruby sprouts, with no significant effect on leaf color. In sprouts, the rutin content of leaves and stalks was higher at 12 h photoperiod and the amount in leaves was 5–7% higher than that of stalks in all combinations and irradiation cycles of LEDs. Among polyphenols, the rutin content in stalks was 1.45–2.97 mg g−1 dry weight and the maximum amount of rutin was obtained from RGB combination of LEDs. In leaves, higher amounts of homoorientin, orientin and vitexin+isovitexin were obtained from the RGB combination and there were significant differences between RGB and other two combinations of LEDs. On the other hand, in between the irradiation cycles used in the study, there were no significant differences for other polyphenols in leaves and stalks of buckwheat sprouts.