Miracle-dz/UniFAR-FTUs huggingface dataset:
Impact Assessment of Different Polymers on Physicochemical Properties of Ibuprofen Loaded Solid Dispersions

In the present study, solid dispersions of ibuprofen were prepared to improve aqueous solubility of ibuprofen. A series of formulations were prepared where PEG 6000 with polymers named PVP K30, cross PVP, poloxamer 237, HPMC ASLF, pregelatinized starch, Na-CMC, Eudragit L100, and kollidon IR were used in different ratios. Among 41 formulations, solid dispersions of ibuprofen in PEG 6000 with each of PVP K30, poloxamer 237, and Na-CMC at ratio of 2:9:7 revealed improved solubility of 952.73 ± 1.31, 878.18 ± 0.97, and 1263.64 ± 1.58 μg/ml, respectively. The physicochemical properties of these preparations were ascertained by FTIR, SEM, DSC, and particle size analyses. FTIR spectrum showed absence of chemical interactions and physical compatibilities between ibuprofen and polymers were confirmed by DSC. Disappearance of individual surface properties in solid dispersions were revealed by SEM studies, which indicated the formation of effective preparations. On the other hand, particle size analysis showed reduction in particle size of ibuprofen from solid dispersions that demonstrated solubility enhancement of ibuprofen. The above studies suggested that solid dispersions of ibuprofen in PEG 6000 at ratios of 2:9:7 with each of PVP K30, poloxamer 237, and Na-CMC were found to be effective to improve aqueous solubility. Dhaka Univ. J. Pharm. Sci. 17(2): 183-190, 2018 (December)
Composition and Properties of Maple Sap, Concentrate, and Permeate

Reverse osmosis is used widely in the maple syrup industry to concentrate maple sap and increase the overall efficiency and profitability of syrup production. Sets of samples from maple producers utilizing a range of sap concentration levels were collected and analyzed to provide a portrait of the physicochemical properties and chemical composition of maple sap, concentrate, and permeate across a single production season. The results reinforce that reverse osmosis functions essentially as a concentration process, without significantly altering the fundamental proportions of sap constituents.
Boosting the Characterization of Heterogeneous Catalysts for H2O2 Direct Synthesis by Infrared Spectroscopy

Infrared (IR) spectroscopy is among the most powerful spectroscopic techniques available for the morphological and physico-chemical characterization of catalytic systems, since it provides information on (i) the surface sites at an atomic level, (ii) the nature and structure of the surface or adsorbed species, as well as (iii) the strength of the chemical bonds and (iv) the reaction mechanism. In this review, an overview of the main contributions that have been determined, starting from IR absorption spectroscopy studies of catalytic systems for H2O2 direct synthesis, is given. Which kind of information can be extracted from IR data? IR spectroscopy detects the vibrational transitions induced in a material by interaction with an electromagnetic field in the IR range. To be IR active, a change in the dipole moment of the species must occur, according to well-defined selection rules. The discussion will be focused on the advancing research in the use of probe molecules to identify (and possibly, quantify) specific catalytic sites. The experiments that will be presented and discussed have been carried out mainly in the mid-IR frequency range, between approximately 700 and 4000 cm−1, in which most of the molecular vibrations absorb light. Some challenging possibilities of utilizing IR spectroscopy for future characterization have also been envisaged.
Vertical GaN p–n diode with deeply etched mesa and the capability of avalanche breakdown

A simple structure with high breakdown voltage and a low leakage current of a vertical GaN p–n diode on a GaN free-standing substrate is demonstrated. We describe a vertical p–n diode with a simple edge termination that has a drift layer etched deeply and vertically. A device simulation revealed that the electric field was more relaxed at the device edge and applied uniformly in the entire device with increasing etching depth. We fabricated the simulated structure and succeeded in reducing the leakage current and improving the breakdown voltage. With this structure, a stable avalanche breakdown can be observed.
Activity and stability of amino-functionalized SBA-15 immobilized 12-tungstophosphoric acid in the oxidative desulfurization of a diesel fuel model with H2O2

Abstract In this study, the stability and the catalytic activity of an ordered mesoporous SBA-15 immobilized 12-tungstophosphoric acid (H3PW12O40, HPW) in the oxidative desulfurization (ODS) of benzothiophene (BT) and dibenzothiophene (DBT) were improved by a post-synthesis-grafting method. In this method, SBA-15 was functionalized to provide a large number of amine groups for the immobilization of HPW through electrostatic binding with (3-aminopropyl) triethoxysilane (APTES) using triflic acid as a protonated agent. The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results show that the structure of functionalized SBA-15 support and the active phase of the HPW remained intact after immobilization. The synthesized PW–H3N+-SBA-15 catalyst showed a high catalytic activity for ODS, achieving BT and DBT conversion of 99.9% and 100% with the reaction conditions of reaction temperature of 50 °C, H2O2 dosage of 1 mL, catalyst dosage of 0.03 g, and reaction time 5 and 1 h, respectively. The catalyst also showed a high reusability after up to four cycles, for which the conversion of the fourth reaction was 90.0% for both BT and DBT.
Effect of Network Structure on Free Volume and Gas Transport Properties of Thiol-Ene and Epoxy-Amine Networks

ii ACKNOWLEDGMENTS . v DEDICATION . vii LIST OF TABLES . xii LIST OF ILLUSTRATIONS . xiii CHAPTER I FREE VOLUME AND GAS TRANSPORT IN POLYMERS: BACKGROUND . 1 1.
Efecto de la selección de espermatozoides mediante centrifugación coloidal sobre la calidad de las dosis de semen de asno refrigeradas y congeladas ; Effect of sperm selection using colloid centrifugation on sperm quality of cooled and frozen-thawed donkey semen

The aim of this study was to determine whether colloid single-layer centrifugation (SLC) improves post-thaw donkey sperm quality and if this potential enhancement is related to ejaculate freezability. Semen from Andalusian donkeys was frozen following a standard protocol. SLC was performed on frozen–thawed semen and post-thaw sperm parameters were compared with uncentrifuged samples. Sperm quality was estimated by integrating in a single value sperm motility (assessed by computer-assisted sperm analysis), morphology and viability (evaluated under brightfield or fluorescence microscopy). Sperm freezability was calculated as the relationship between sperm quality obtained before freezing and after thawing. Ejaculates were classified into low, medium and high freezability groups using the 25th and 75th percentiles as thresholds. All sperm parameters were significantly (P, 0.01) higher in SLC-selected samples in comparison to uncentrifuged frozen–thawed semen and several kinematic parameters were even higher than those obtained in fresh semen. The increment of sperm parameters after SLC selectionwas correlatedwith ejaculate freezability, obtaining the highest values after SLC in semen samples with low freezability. We concluded that, based on the spermquality parameters evaluated, SLC can be a suitable procedure to improve post-thaw sperm quality of cryopreserved donkey semen, in particular for those ejaculates with low freezability. Additional keywords: cryopreservation, sperm freezability. Received 3 August 2013, accepted 17 October 2013, published online 4 December 2013
Microfluidic chip-inductively coupled plasma mass spectrometry for trace elements and their species analysis in cells

Abstract Accurate identification and quantification of trace elements and their species in cells is an important prerequisite for the exploration of their physiological function and related mechanisms of process involving trace elements/species in human body. Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful analytical instrument for trace elements detection, while it still suffers from insufficient limits of detection, interference from complex cell matrix, and incompatible sample consumption in cells analysis. Microfluidic chips which possess advantages of low sample/reagent consumption, rapid analysis speed and high spatial resolution provide perfect miniaturized and integrated platforms for cell analysis. In this article, microfluidic chip-ICP-MS techniques for trace elements and their species analysis in cells were reviewed. Both chip-based pretreatment techniques (e.g., magnetic solid phase microextraction (MSPME), monolithic capillary microextraction (MCME), liquid phase microextraction (LPME)) including chip-based array microextraction techniques for trace elements and their species analysis and droplet chip for single cell analysis were introduced. The newly developed methods of microfluidic chips in combination with ICP-MS for trace elements and their species analysis in small numbers of cells and even single cell were critically discussed, including chip-based MSPME/MCME/LPME-(electrothermal vaporization-ICP-)MS, on-line chip-based array MSPME/MCME-ICP-MS, on-line chip-based array MSPME-high performance liquid chromatography-ICP-MS and online droplet chip-time-resolved ICP-MS. These methodologies were demonstrated with high sensitivity, high throughput, good matrix resistance and low sample/reagent consumption, contributing to the quantification of trace elements/species in cells and even single cells. Relevant 20 references are included herein, and the development trend of microfluidic chip-ICP-MS techniques for cells analysis is prospected.
Carbon Quantum Dots–Modified Interfacial Interactions and Ion Conductivity for Enhanced High Current Density Performance in Lithium–Sulfur Batteries

Significant progress has achieved for developing lithium–sulfur (Li–S) batteries with high specific capacities and excellent cyclic stability. However, some critical issues emerge when attempts are made to raise the areal sulfur loading and increase the operation current density to meet the standards for various industrial applications. In this work, polyethylenimine‐functionalized carbon dots (PEI‐CDots) are designed and prepared for enhancing performance of the Li–S batteries with high sulfur loadings and operation under high current density situations. Strong chemical binding effects towards polysulfides and fast ion transport property are achieved in the PEI‐CDots‐modified cathodes. At a high current density of 8 mA cm−2, the PEI‐CDots‐modified Li–S battery delivers a reversible areal capacity of 3.3 mAh cm−2 with only 0.07% capacity decay per cycle over 400 cycles at 6.6 mg sulfur loading. Detailed analysis, involving electrochemical impedance spectroscopy, cyclic voltammetry, and density functional theory calculations, is done for the elucidation of the underlying enhancement mechanism by the PEI‐CDots. The strongly localized sulfur species and the promoted Li+ ion conductivity at the cathode–electrolyte interface are revealed to enable high‐performance Li–S batteries with high sulfur loading and large operational current.
New water/water emulsions stabilized by Pickering effect

Les emulsions eau/eau (W/W) ont suscite un grand interet en raison de leur potentiel d'application dans differentes industries telles que l'agroalimentaire, les produits pharmaceutiques, les cosmetiques et les soins personnels. Le caractere particulier des emulsions W/W est leur stabilisation par ajout de particules. L’objectif de ce travail de these est de comprendre cet aspect en etudiant une emulsion modele W/W a base de dextran et du poly(oxyde d'ethylene) stabilisee par des particules a base de proteines du lactoserum. Dans un premier temps, nous avons etudie l'effet de la morphologie des particules proteiques et leur partitionnement sur la stabilite des emulsions W/W. En particulier, la stabilite s’est revelee dependre de la structure des particules quand ses derniers etaient sous forme de microgels, d’agregats fractals ou de fibrilles. Il a ete montre que la stabilite s'ameliorait lorsque les particules se localiser preferentiellement dans la phase continue. Deuxiemement, nous avons etudie la gelification, des microgels et des agregats fractals, induite en reduisant le pH entre 6,5 et 3,5 ou en ajoutant 0,3 M NaCl a pH 7,0 aussi bien quand l’exces des particules se situe dans la phase continue ou dispersee. Dans le premier cas, un reseau se forme dans la phase continue de dextran, permettant d’inhiber le cremage des gouttelettes de PEO, les agregats fractals etant plus efficaces que les microgels. Dans le second cas, des particules proteiques denses pourraient etre formees par gelification des gouttelettes de dextran dispersees. Finalement, nous avons explore l'adsorption des proteines natives sur les particules de latex et leur capacite a stabiliser les emulsions.
Water conservation and the common pool problem: Can pricing address free-riding in residential hot water consumption?

Water is an increasingly scarce resource. It is often distributed such that consumers do not face any marginal cost of consumption, creating a common pool problem. For instance, tenants in multi-family buildings can often consume both hot and cold water at zero marginal cost. Using high-frequency data over many years, we analyze how the introduction of apartment-level metering and billing (IMB) affects hot water consumption. We find that introducing a marginal cost, reflecting the market price, decreases consumption drastically by 26%. Hence, price interventions can curb free-riding behavior and help the conservation of cheap but precious resources. Our results also show that heavy water users in the top consumption quartile account for 72% of the reduction. Moreover, cost-benefit calculations indicate that IMB for hot water is a cost-effective policy tool for reducing water and energy consumption.
Dual Interface Exciplex Emission of Quinoline and Carbazole Derivatives for Simplified Nondoped White OLEDs

Isomeric quinoline and 9-phenylcarbazole derivatives with different linking topology were synthesized as versatile exciplex-forming materials. Their exciplex forming properties were examined. The studied compounds showed dual electron-donating or accepting nature and formed blue emitting excited complexes with acceptor 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine and orange emitting exciplexes with the donor 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine. The solutions and solid films of both the synthesized compounds showed violet fluorescence. Compound with meta-substitution exhibited higher energy of triplet level (2.64 eV) and higher ionization potential value (6.21 eV) in comparison to para-substituted one. Higher 5% weight loss and glass transition temperatures of 339 and 84 °C were observed for para-isomer. The studied compounds were characterized by bipolar charge-transport properties with hole- and electron mobilities exceeding 10–4 cm2 V–1 s–1 at electric fields exceeding 105.
Effect and Characterization of Stone–Wales Defects on Graphene Quantum Dot: A First-Principles Study

A first principles based density functional theory (DFT) has been employed to identify the signature of Stone–Wales (SW) defects in semiconducting graphene quantum dot (GQD). Results show that the G mode in the Raman spectra of GQD has been red shifted to 1544.21 cm − 1 in the presence of 2.08% SW defect concentration. In addition, the intensity ratio between a robust low intense contraction–elongation mode and G mode is found to be reduced for the defected structure. We have also observed a Raman mode at 1674.04 cm − 1 due to the solo contribution of the defected bond. The increase in defect concentration, however, reduces the stability of the structures. As a consequence, the systems undergo structural buckling due to the presence of SW defect generated additional stresses. We have further explored that the 1615.45 cm − 1 Raman mode and 1619.29 cm − 1 infra-red mode are due to the collective stretching of two distinct SW defects separated at a distance 7.98 Å. Therefore, this is the smallest separation between the SW defects for their distinct existence. The pristine structure possesses maximum electrical conductivity and the same reduces to 0.37 times for 2.08% SW defect. On the other hand, the work function is reduced in the presence of defects except for the structure with SW defects separated at 7.98 Å. All these results will serve as an important reference to facilitate the potential applications of GQD based nano-devices with inherent topological SW defects.
Theoretical Contribution Towards Understanding Specific Behaviour of “Simple” Protein‐film Reactions in Square‐wave Voltammetry

Surface reactions of uniformly adsorbed redox molecules at working electrode surface are seen as adequate models to studying chemical reactivity of many lipophilic enzymes. When considered under pulse voltammetric techniques, these systems show several uncommon features, whose origin is still not completely clear. The phenomena of “quasireverible maximum”, “splitting” of the net peak in square-wave voltammetry, and the very steep descent of Faradaic currents of simple surface redox reactions exhibiting fast electron transfer are just some of the features that make these systems quite interesting for further elaborations. In this work, we present a set of theoretical calculations under conditions of square-wave voltammetry in order try to explain some of aforementioned phenomena. The major goal of our work is to get insight to some voltammetric and chrono-amperometric features of two considered surface reactions, i. e. (1) the “simple” surface redox reaction, and (2) surface redox reaction coupled to follow-up irreversible chemical reaction of electrochemically generated redox species (or surface ECirr). We focus on the role of created Red(ads) (here in the reduction pulses only) to the current components of calculated square-wave voltammograms exhibiting fast electrode reaction. We show that the irreversible chemical removal of electrochemically generated Red(ads) species, created in the potential pulses where half-reaction of reduction Ox(ads)+ne! Red(ads) is “defined” to take place, causes significant increase of all square-wave current components. The results presented in this work show how complex the chrono-amperometric features of surface redox reactions under pulse voltammetric conditions might be. In addition, we point out that both half reactions of a given simple surface redox process can occur, at both, “only reduction” and “only oxidation” potential pulses in square-wave voltammetry. This, in turn, contributes to the occurrence of many phenomena observed in simple protein-film voltammetry reactions. The effects of chemical reaction rate to the features of calculated squarewave voltammograms of surface ECirr systems with fast electrode reaction are reported for the first time in this work.
IMPROVING ELECTROLYTE TRANSPORT INSIDE THE LI-ION POROUS ELECTRODES USING MICROCHANNELS

Effects of using microchannels on the electrolyte transport inside the positive and negative electrodes have been investigated in this paper. A two-dimensional Lattice Boltzmann Method (LBM) simulation was carried out and a two-phase intermolecular potential model was utilized to investigate the microscopic behavior of the electrolyte flow in the porous electrodes. It was found that embedding microchannels inside the electrodes significantly improves the electrolyte transport inside both positive and negative electrodes. Furthermore, there is an optimum number of microchannels after which increasing the number of microchannels has no positive effect on the electrolyte transport inside the electrodes. Finally, the number of microchannels in the anode should be less than the number of the microchannels in the cathode in order to uniform electrolyte transport inside the both negative and positive electrodes.
Enhanced Water Desalination by Increasing the Electroconductivity of Carbon Powders for High-Performance Flow-Electrode Capacitive Deionization

Flow-electrode capacitive deionization (FCDI) can be improved via enhanced charge transfer by increasing the flow-electrode (FE) conductivity. Since water is the main component of FE (>70%), the key to improving the electroconductivity lies in the properties of carbon materials. In this work, three types of carbon powders, i.e., activated carbon (AC), mesoporous carbon, and carbon nanotubes (CNTs), were employed in FEs to investigate the influence of powder properties on the FCDI performance. The morphology and structure of powders and electrochemical behavior and rheology of FEs were investigated to reveal the relationship between FE properties and desalination performance. Results show that, due to their unique electrosorption behavior, excellent conductivity, and enhanced conductivity through a bridging effect, CNT-based FE (carbon loading: 3 wt %) achieved the fastest (8.3 mg s–1 m–2) and the most stable desalination (charge efficiency: 93.3%). A faster desalination (13.2 mg s–1 m–2), due to significa.
Impact of nano-sized cerium oxide on physico-mechanical characteristics and thermal properties of the bacterial cellulose films

I. V. Gofman, A. L. Nikolaeva, A. K. Khripunov, A. V. Yakimansky, E. M. Ivan’kova, D. P. Romanov, O. S. Ivanova, M. A. Teplonogova, V. K. Ivanov Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004, Bolshoi prospect 31, Saint Petersburg, Russia Saint Petersburg State University, Institute of Chemistry, 198504, Universitetskii prospect 26, Peterhof, Saint Petersburg, Russia Institute of Silicate Chemistry, Russian Academy of Sciences, 199034, Adm. Makarova emb. , 2, Saint Petersburg, Russia Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect 31, Moscow, Russia
Are there "winner-takes-it-all" effects in blockchain user adoption?

There are many public blockchains with various levels of success when it comes to sustained user adoption. This paper investigates whether some blockchains are more likely to dominate others in the long-run, i.e., whether there are "winner-takes-it-all" dynamics or whether a blockchain's adoption shares become stable. Our theory predicts that, although we may observe both positive and negative network effects in the short-run, user adoption share sequences behave like martingales in the limit and thus, achieve stability. This result arises from the fact that more (less) adopted blockchains tend to have a lower (higher) likelihood of capturing significant fractions of growing user numbers and that adoption rate sequences converge to their sample mean in the limit. We further characterize the limiting distribution of adoption shares. Empirically, we test whether some of the existing public blockchains' adoption shares behave like martingales. Two of the oldest blockchains in our sample, Bitcoin and Litecoin, do not reject our martingale hypothesis while others do not (yet) behave like martingales due to limited information content and length of their transaction history. Finally, Bayesian users update their beliefs about the distribution of adoption shares over time and are thus better able to make adoption decisions regarding those blockchains that already behave like martingales.