Moderate Conversion Research Articles

Functionalized nanohybrids with rod shape for improved chemo-phototherapeutic effect against cancer by sequentially generating singlet oxygen and carbon dioxide bubbles.

The application of hybrid nanocarriers is expected to play an active role in improving treatment of chemotherapy and phototherapy. Herein, a nanohybrid with a core of mesoporous silica nanorods and shell of folate-functionalized zeolite imidazole framework (ZIF-8/FA) was synthesized via polydopamine (PDA)-mediated integration. A chemotherapeutic drug (DOX), bubble generator (NH4HCO3, ABC), and photosensitive agent (ICG) were simultaneously loaded into the delivery system to construct smart ZIF-8/FA-coated mesoporous silica nanorods (IDa-PRMSs@ZF). We found that ICG endowed the designed delivery system with a moderate photothermal conversion efficiency of 26.06% and the capacity to release 1O2. The produced hyperthermia caused ABC to decompose and further generate carbon dioxide bubbles, thereby facilitating DOX release, sequentially. Importantly, the underlying mechanism was also investigated using mathematical kinetic modeling. The tumor inhibition rate of IDa-PRMSs@ZF under NIR irradiation reached 83.8%. This study provides a promising strategy based on rod-shaped nanohybrids for effective combination antitumor therapy.

Dynamic Analysis of Risk to Water Quality in the Baimei Reservoir Conservation Area, Fujian Province, China

The security of drinking water resources is an important concern for human survival. The extensive use of geographic information system and remote sensing data in risk assessments of water quality from a spatiotemporal perspective can complement water resource management. In this study, we investigated Baimei reservoir conservation area, Fujian Province, China. The quantitatively inversed leaf area index was used to represent the vegetation growth condition in simulations of the hydrological process using soil and water assessment tool. According to the simulation results, the spatial distribution of the risk to water quality was mainly related to the land-use condition, and the temporal distribution of the risk to water quality was mainly related to the precipitation dynamics. Single factor analysis of various scenarios showed that uncontrolled expansion of agricultural land (scenario A) would lead to an overall average increase of 231.9% in the total nitrogen (TN) load in the basin. By contrast, if agricultural lands are all transformed into forests (scenario B), then the overall TN load in the basin would decrease by an average of 20.8%. In practical terms, conversion of sloping agricultural lands to forests (scenario C) could reduce the overall TN load by 17.0%. Thus, moderate conversion of agricultural lands to forests can reduce the pollution load effectively. The simulation results obtained for scenarios with adjustments to the fertilization time and amount showed that applying fertilizer on rainy days would increase the risk to water quality compared with days without rain. The method developed in this study can be applied for dynamic analysis in water quality risk assessments of water conservation areas and can provide a scientific reference for promoting ecological management strategies and sustainable development at the regional scale.

Catalytic oxidation properties of an acid-resistant cross-bridged cyclen Fe(II) complex. Influence of the rigid donor backbone and protonation on the reactivity.

The catalytic properties of an iron complex bearing a pentadentate cross-bridged ligand backbone are reported. With H2O2 as an oxidant, it displays moderate conversions in epoxidation and alkane hydroxylation and satisfactory ones in aromatic hydroxylation. Upon addition of an acid to the reaction medium, a significant enhancement in aromatic and alkene oxidation is observed. Spectroscopic analyses showed that accumulation of the expected FeIII(OOH) intermediate is limited under these conditions, unless an acid is added to the mixture. This is ascribed to the inertness induced by the cross-bridged ligand backbone, which is partly reduced under acidic conditions.

Panchromatic small-molecule organic solar cells based on a pyrrolopyrrole aza-BODIPY with a small energy loss

A small photon energy loss (Eloss) is one of the requisites for achieving near-infrared (NIR) small-molecule organic solar cells (SM-OSCs). Herein, we present two novel pyrrolopyrrole aza-BODIPY (PPAB)-based panchromatic chromophores, TT-2PPAB and DFBT-2PPAB, with an acceptor-donor-acceptor configuration for photovoltaic studies. Among them, in combination with [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) acceptor, TT-2PPAB exhibits a moderate power conversion efficiency (PCE) of 3.11% due to an Eloss of 0.48 eV, which is smaller than the empirical limit of 0.6 eV. Based on the electrochemistry and theoretical calculations, we revealed that the efficient photovoltaic performance of the TT-2PPAB-based device can be ascribed to the sufficiently deep LUMO level of TT-2PPAB for charge transfer to PC71BM.

Evaluation of nutritional indices and conversion efficiency in multivoltine, cross-breeds and popular bivoltine double hybrid of mulberry silkworm Bombyx mori

In sericulture, the nutritional ability of mulberry varieties and conversional traits of silkworm breeds have an important role in the improvement of silk yield. The present study aims to evaluate silk conversion efficiency in a few breeds and hybrids. The silkworm Bombyx mori breeds and hybrids viz., MVI, PMxCSR2, MV1xS8 and FC1xFC2 were assessed during the fifth instar, with PM as control during the years 2019 and 2020. The study focused on the nutritional indices and conversion traits of silkworms by feeding V1 mulberry leaves, reared under the same environmental conditions. Significant variations were observed among silkworm breeds and hybrids. The test breed and hybrids were found superior to the control PM, which recorded an ingestion of 2.33g and a conversion ability of 8.65%. The bivoltine double hybrid FC1xFC2 showed high food ingestion (3.25g) and conversion (18.18%), followed by the cross breed MV1xS8 with moderate ingestion (3.17g) and conversion (16.63%). The values for ingesta and conversion in PMxCSR2 were 3.43 g and 8.92%, respectively. Further, in respect of Efficiency Conversion of Ingesta (ECI) of shell, the highest conversion of shell is shown by FC1xFC2 (13.56%) followed by MV1xS8 (10.14%), MV1 (9.73%) and PMxCSR2 (9.36%), having a percentage difference of 63.27%, 36.08%, 32.11% and 28.30% respectively over PM. The silk conversion efficiency of bivoltine double hybrid FC1xFC2 was found to be profoundly high, followed by multivoltine cross-breeds and pure line (PM) tested.

Azulene‐based Hole Transport Materials with Proper Electronic Properties for Perovskite Solar Cells

AbstractWith the advantages of adjustable structure and energy level, organic small molecules have been attracting much attention as hole transport materials (HTMs). Azulene was widely used in charge transfer materials for organic electronic devices. In this paper, two HTMs (Azu‐TPA and Azu‐OMeTPA) based on azulene core unit were synthesized by concise routes. Both Azu‐TPA and Azu‐OMeTPA demonstrate suitable molecular orbital energy levels as HTMs. Their hole mobility are over 10−4 cm2 V−1 S−1 and conductivity are over 10−4 S cm−1, comparable with that of Spiro‐OMeTAD. Besides, they exhibit good hydrophobicity. Applied in PSCs, moderate power conversion efficiency (PCE) up to 15.41% was obtained. These results suggest the potential of azulene as a build block to develop HTMs with desirable electronic properties for perovskite solar cells (PSCs).

Single-step fabrication of templated Li4SiO4-based pellets for CO2 capture at high temperature

The present study proposes a novel single-step method for the fabrication of macro-porous K2CO3-doped Li4SiO4 pellets for carbon dioxide capture at high temperature and low concentration of CO2. Cylindrical pellets were directly prepared by mechanical compression of precursors and then calcination at high temperature. The pellets characterization evidenced that, during the calcination process, both the synthesis of Li4SiO4 and the development of macro-porosity into pellets occurred due to the release of decomposition gases. The obtained pellets were tested for CO2 capture at 580 °C and CO2 partial pressure of 0.04 atm, and the long-time stability was evaluated by multiple sorption/desorption cycles operating at moderate Li4SiO4 conversions. This single-step pelletization method allowed to produce a sorbent with high CO2 sorption capacity (253.2 mg CO2/g sorbent) even at low concentration of CO2. Moreover, the single-step pellets displayed a good cyclic stability over 200 adsorption/desorption cycles, making them suitable for CO2 capture in industrial applications in a fixed bed reactor.

Dry gel assisting crystallization of bifunctional CuO–ZnO–Al2O3/SiO2–Al2O3 catalysts for CO2 hydrogenation

A series of bifunctional catalysts CuO–ZnO–Al2O3/SiO2–Al2O3 (CZA/SA) with different SA/CZA ratios were prepared by dry gel assisting crystallization method. The catalytic performance of bifunctional catalysts for one-step synthesis of methanol (MeOH) and dimethyl ether (DME) from CO2 hydrogenation was investigated. The results showed that compared with Cu/ZnO/Al2O3, CZA/SA catalyst significantly improved the selectivity of DME and MeOH and reduced the CO selectivity with moderate CO2 conversion. The catalyst structure was characterized by X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR), which further confirmed that the active site of methanol generation was the Cu–ZnO interface with a strong interaction rather than solo Cu or ZnO crystallite, which could enhance the hydrogenation function and inhibit reverse water gas shift reaction. Compared with the physical mixing method, the dry gel assisting crystallization method could flexibly adjusted the acid strength and the amounts of acid sites, which was benefit for enhancing dehydration function to improve the selectivity of DME.

Co decorated low Pt loading nanoparticles over TiO2 catalyst for selective hydrogenation of furfural

Selective hydrogenation of carbonyl groups in biobased chemicals to alcohols is crucial to the economics of broadly sustainable product portfolios. Furfuryl alcohol (FOL), the most prominent chemical of hemicellulose, has been produced by furfural (FAL) hydrogenation over heterogeneous catalysts. In this work, we show the outstanding activity, selectivity, and stability of supported bimetallic PtCo nanoparticle (np) synthesized from a pre-made stock solution of zero valent atomic Pt precursor and Co2(CO)8. With only 0.5 wt% Pt on TiO2, the np-PtCo/TiO2 catalyst exhibits TOF of 14,023 h−1 at 30 °C with > 99.9% FOL selectivity. The stability of the np-PtCo/TiO2 catalyst is verified by the steady performance in reuses at both moderate and full conversions. The oxyphilic Coδ+ in the PtCo nanoparticles induces nucleophilic chemisorption of -CO, resulting in deeply polarized CO bond. DFT calculated FAL adsorption energies on np-Pt and np-PtCo are − 0.22 eV and − 0.74 eV, respectively.

Application of gold and palladium nanoparticles supported on polymelamine microspheres in the oxidation of 1-phenylethanol and some other phenyl substituted alcohols

Melamine formaldehyde and melamine resorcinol formaldehyde microspheres were decorated with Au and Pd nanoparticles and applied as heterogeneous catalysts in the oxidation of 1-phenylethanol. The catalysts showed similar activities irrespective of the support employed. Moderate conversion activities of 48–50% were achieved when using acetonitrile as solvent; however, when employing water as solvent, the supported catalysts formed a three-phase, emulsion system which facilitated the catalytic conversion of 1-phenylethanol to acetophenone at much higher conversions of around 83%. The oxidant, TBHP, decomposed rapidly in acetonitrile, whilst it remained stable in aqueous solution, leading to the enhanced activities observed when using water as solvent. These systems also proved to be recyclable for up to five cycles, with only slight loss of activity observed; this can be attributed to the physical loss of catalyst during the workup procedure conducted between each cycle.

Co-production of levulinic acid and lignin adsorbent from aspen wood with combination of liquid hot water and green-liquor pretreatments

Efficient lignocellulosic fractionation and conversion into platform chemicals provide a considerable opportunity for the industrial operation of a lignocellulosic biorefinery. However, single-step pretreatments are often insufficient to overcome biomass recalcitrance as the existence of insoluble lignin generally restricts component fractionation and conversion. This study performed a two-step pretreatment, consisting of sequential liquid hot water (LHW) and green-liquor (GL), for bioprocessing of aspen biomass into bioproducts such as glucose, levulinic acid (LA), and lignin adsorbent. The two-step pretreated glucan-rich solid displayed high cellulose accessibility, which is responsible for 94% of the glucose yield. The optimized LHW pretreatment (200 °C, 40 min) solubilized 91% of the hemicellulose, which together with monomeric sugars in the hydrolysate solution was straightly heated at 190 °C for 80 min and yielded 72.49% of LA in the presence of sulfuric acid as a catalyst. Moreover, GL post-treatment (Na2CO3+Na2SO3) solution maximized the delignification at 78% from LHW pretreated substrate. The isolated lignin possessed a remarkable ability for Cd2+ and Pb2+ uptake with maximized adsorption values of 250 mg/g and 228 mg/g, respectively. Finally, energy analyses showed that moderate lignocellulosic conversion could obtain an energy recovery of 85%, providing a sustainable pathway for biorefinery approaches.

Exploring Photoswitchable Properties of Two Nitro Nickel(II) Complexes with (N,N,O)-Donor Ligands and Their Copper(II) Analogues.

Two photoswitchable nickel(II) nitro coordination compounds and their copper(II) analogues are reported. In all these systems, the metal center is chelated by (N,N,O)-donor ligands containing either 2-picolylamine or 8-aminoquinoline fragments. The studied compounds were thoroughly investigated using crystallographic and spectroscopic techniques supplemented by computational analysis. They are easy to synthesize and stable, and all compounds undergo the nitro group isomerization reaction. Nevertheless, there are significant differences between the copper and nickel systems regarding their structural and switchable properties. According to the solid-state IR spectroscopy results, 400–660 nm light irradiation of the ground-state (η2-O,O′)-κ-nitrito copper(II) complexes at 10 K induces a rather moderate conversion to a metastable linkage isomer, which is visible only up to approximately 60–80 K. In turn, upon visible light irradiation (ca. 530 nm excitation wavelength), the ground-state nitro isomers of the examined nickel(II) complexes transform into the endo-nitrito forms. It was possible to achieve about 35% conversion for both nickel(II) systems and to determine the resulting crystal structures at 160 K in the case of single crystals after 30–45 min of exposure to LED light (crystals decayed with longer irradiation), and roughly 95% conversion was achieved for thin-film samples as indicated by the IR spectroscopy results. Traces of the endo-nitrito linkage isomers remained up to 200–220 K, and the isomerization reaction was proven to be fully reversible.

Hypervalent iodine‐based initiators and efficient chain transfer agents for the synthesis of branched polymers from crosslinkers

AbstractThe synthesis of hyperbranched polymers with alkyl chloride‐type chain ends was accomplished by the copolymerization of methyl methacrylate and a crosslinker, ethylene glycol dimethacrylate, in the presence of 1‐chloro‐1,2‐benziodoxol‐3(1H)‐one (BIO‐Cl), which served as both a radical initiator and an efficient chain transfer agent. The polymerizations were carried out under thermal (80 °C) and photochemical (irradiation with visible light) conditions. As a result of the transfer of Cl atoms from BIO‐Cl to the propagating radicals, gelation was delayed to high monomer conversions and, until that point, soluble branched polymers were formed. Even pure crosslinker could be polymerized to moderate conversions (>15%, depending on the amount of added BIO‐Cl), yielding branched polymers prior to formation of networks. The effect of the concentrations of crosslinker and hypervalent iodine(III) compound on the outcome of the (co)polymerizations as well as the kinetic features of Cl transfer and decomposition of BIO‐Cl were studied in detail. © 2022 Society of Industrial Chemistry.

Dry reforming of methane by microsecond pulsed dielectric barrier discharge plasma: Optimizing the reactor structures

Dry reforming of CH4 process can convert greenhouse gases into high-value-added fuels and chemicals with its broad application prospects in environmental protection and renewable energy. Non-thermal plasma is considered an effective alternative method because it can activate CH4 and CO2 under low temperature and atmospheric pressure. This paper is aimed to optimize the plasma-assisted dry reforming of CH4 process in a unipolar microsecond pulsed coaxial dielectric barrier discharge by investigating the effects of reactor structures. The results show that the conversions of reactants and the yields of syngas were significantly affected by the reactor structures. Specifically, a multi-stage or foil external electrode and negative polar discharge could promote CH4 and CO2 conversions, gas product yields, and energy conversion efficiencies. For different electrodes, the maximal conversions of CH4 and CO2 were 20.4% and 14.1%, with an energy conversion efficiency of 4.4% under our experimental conditions. Higher conversions, yields, and energy conversion efficiencies were obtained with lower power input when applying heat insulation measures. CH4 conversion was promoted to 27.9% with a moderate energy conversion efficiency of 3.8%, but the conversion of CO2 was only 12% when packing materials into the reactor. The results can provide specific guidance for designing plasma or plasma-catalytic dry reforming reactor.

Electrocarboxylation of Spiropyran Switches through Carbon‐Bromide Bond Cleavage Reaction

AbstractThis manuscript deals with carbon capture and utilization to synthetize high‐added chemicals using CO2 as a C1‐organic building block for C−C bond formation. The study focuses on the electrocarboxylation of 1,3,3‐trimethylindolino‐6′‐bromobenzopyrylospiran switch (Br‐BIPS). Prior to the electrocarboxylation process, the electrochemical reduction mechanism of Br‐BIPS and CO2 is disclosed in polar aprotic solvents using two different cathodes (glassy carbon and silver) under nitrogen atmosphere. Once the role of the cathode in the reduction carbon‐bromide bond cleavage is understood, carboxylated spiropyran derivatives can be synthesized in moderate yields and conversion rates through an electrocarboxylation process using CO2 silver cathode and polar aprotic solvents. The “green” efficient route described in the current work would open a new sustainable strategy for designing and building “smart” surfaces with switchable physical properties.

Development of a Performance Analysis Model for Free-Piston Stirling Power Convertor in Space Nuclear Reactor Power Systems

Space nuclear reactor power system (SNRPS) is a priority technical solution to meet the future space power requirement of high-power, low-mass, and long-life. The thermoelectric conversion subsystem is the key component of SNRPS, which greatly affects the performance, quality, and volume of SNRPS. Among all kinds of proposed thermoelectric conversion technologies, the free-piston Stirling power converter (FPSPC) has become a preferred conversion technology for small-scale advanced SNPRS due to its moderate waste heat emission temperature and high conversion efficiency, mainly composed of a linear alternator and free-piston Stirling engine (FPSE). For studying the performance of FPSPC, a quasi-steady flow thermodynamic cycle analysis model considering parasitic heat losses has been developed for FPSE. And then the performance analysis model for FPSPC has been established by coupling the thermodynamic cycle analysis model with the mechanical motion model of the piston and volt-ampere characteristic model of the linear alternator. Furthermore, the analysis model was compared and validated by the GPU-3 Stirling engine’s experimental data. The performance parameters of Component Test Power Converter (CTPT) FPSPC designed by NASA for SNRPS were also analyzed. The results show that the amplitudes position of CTPC displacer and piston are 15.1 mm and 11.2 mm, respectively. The corresponding average electric power output of CTPC is 17.316 kW. The input thermal power to the CTPT heater is 66.1 kW, leading to the converter efficiency of 26.2%. The average current and voltage of the CTPC alternator are 86.38 A and 193.15 V, respectively. Among all kinds of parasitic energy losses, the regenerator heat loss accounts for the largest proportion, with an average of about 12.7 kW. The effects of cooler and heater temperature on the performance of CTPC FPSPC were also studied.

Construction of 2D-coal-based graphene/2D-bismuth vanadate compound for effective photocatalytic CO2 reduction to CH3OH

Scalable and sustainable photocatalytic technology can convert CO2 to valuable hydrocarbons, which requires highly efficient and inexpensive photocatalyst with a broad light absorption range, high stability and fast carrier separation efficiency. Herein, a nanostructure with 2D/2D conformation consisting of BiVO4 and coal-based graphene oxide (CGO) were fabricated by hydrothermal method, which achieves efficient photoreduction of CO2 to CH3OH. Surprisingly, this nanostructure exhibits a significantly enhanced photocurrent density (0.95 mA/cm2), good CO2 adsorption capacity (1.34 cm3/gSTP) and medium stability. Moreover, the optimized 10-CGO/BiVO4 composite shows moderate CO2 conversion activity with a CH3OH production of 537.78 μmol/g h under light irradiation, which is approximately 6.47 times higher than that of BiVO4 nanosheets. The enhanced photocatalytic activity can be attributed to the following three points: broadened visible light absorption ability, unique ultra-thin structure and abundant surface active sites; effective photocarriers separation efficiency and reduced interfacial resistance at their heterojunction between BiVO4 and CGO nanosheets; CGO as co-catalyst with an electron-transfer path coupling with CGO can expedite the separation speed of carriers of photocatalyst, reduce the interface resistance and enrich surface active sites. This work provides inspiration for high performance binary photocatalyst in solar-chemical energy conversion process.

СОЦИАЛЬНО-ПСИХОЛОГИЧЕСКИЕ ДЕТЕРМИНАНТЫ ИНТЕРЕСА К ПСИХОЛОГИИ У МОЛОДЕЖИ

The empirical study aims at studying the preferences of young people in various fields of psychology, determining their degree of interest in certain types and forms of psychological knowledge, as well as identifying the main external and internal determinants of interest in psychology among young people. The majority of respondents consider psychology as the science of the psyche, mental processes and thinking. The most interesting area of psychology for them is personality psychology and the less preferred is advertising psychology. Psychology attracts as it is not static but actively developing, often discussed in the media, the number of people with mental disabilities of young age has increased, and psychology is also in demand on a practical level. Psychology allows respondents to understand first of all the people around them and themselves. At the same time, the results of the study show that most of the respondents have an average level of reflexivity, which indicates their moderate conversion of consciousness to themselves and a moderate level of reflection on their mental state. Most of the subjects have a general average level of self-regulation of behavior. At the same time, most of the subjects have a personality orientation towards themselves, with the predominance of motives for their own well-being, striving for personal primacy, prestige, which does not correspond to the nature of practical psychology, where the priority remains for relationships between people. The main values for them are independence and security, the last thing they would like is to follow traditions, including psychological.

Identification of mild cognitive impairment subtypes predicting conversion to Alzheimer’s disease using multimodal data

Mild cognitive impairment (MCI) is a high-risk condition for conversion to Alzheimer's disease (AD) dementia. However, individuals with MCI show heterogeneous patterns of pathology and conversion to AD dementia. Thus, detailed subtyping of MCI subjects and accurate prediction of the patients in whom MCI will convert to AD dementia is critical for identifying at-risk populations and the underlying biological features. To this end, we developed a model that simultaneously subtypes MCI subjects and predicts conversion to AD and performed an analysis of the underlying biological characteristics of each subtype. In particular, a heterogeneous mixture learning (HML) method was used to build a decision tree-based model based on multimodal data, including cerebrospinal fluid (CSF) biomarker data, structural magnetic resonance imaging (MRI) data, APOE genotype data, and age at examination. The HML model showed an average F1 score of 0.721, which was comparable to the random forest method and had significantly more predictive accuracy than the CART method. The HML-generated decision tree was also used to classify-five subtypes of MCI. Each MCI subtype was characterized in terms of the degree of abnormality in CSF biomarkers, brain atrophy, and cognitive decline. The five subtypes of MCI were further categorized into three groups: one subtype with low conversion rates (similar to cognitively normal subjects); three subtypes with moderate conversion rates; and one subtype with high conversion rates (similar to AD dementia patients). The subtypes with moderate conversion rates were subsequently separated into a group with CSF biomarker abnormalities and a group with brain atrophy. The subtypes identified in this study exhibited varying MCI-to-AD conversion rates and differing biological profiles.

Complejos (η6-Arene)-tricarbonylchromium(0) complexes used in olefin hydroformylation reaction with syngas

Aldehydes are compounds with a great scientific interest in its chemical applications, especially to consider a raw material in many industrially and process for manufacturing secondary products, such as, solvents, biodegradable detergents, pharmaceuticals, surfactants, lubricants, other. In this paper we describe the use of commercial chromium carbonyl: [Cr(CO)6] (1), [Cr(CO)3(η6-C6H6)](2a), [Cr(CO)3(η6-C6H5CH3)] (2b), [Cr(CO)3(η6-C8H8O2)] (2c) y [Cr(CO)3(η6-C7H8)] (3), as catalytic precursors in hydroformylation reactions of 1-hexene and cyclohexene with syngas CO/H2 and CO2/H2 in homogeneous phase. In all cases, the reactions conditions (temperature, pressure, CO/H2 ratio, solvents, substrate/catalyst ratio) were optimized and additionally, the catalytic activity was studied employing excess ligands condition or mercury test to verify the homogeneity in the catalytic system. Under optimal conditions, a high percent yield and good selectivity for linear versus branched aldehydes, and for the CO2/H2 system, all the catalysts showed moderate conversion towards linear, branched aldehydes and alcohols with and without NaCl.