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Synergistic therapeutic effect through the intracellular co-delivery of chemotherapy and biomacromolecule drugs is a novel strategy for improving tumor treatment effectiveness. A triblock copolymer, poly(acrylic acid)-poly(N, Ndiisopropylaminoethyl methacrylate)-poly(N-vinylcaprolactam) (PAA-PDPA-PNVCL), was designed and synthesized for the construction of smart responsive drug carriers. The structure of the polymers was verified by nuclear magnetic resonance spectroscopy (¹H-NMR) and fluorescence spectrophotometer (FL). The transmittances of the polymer solutions under different pH values or temperatures were measured by ultraviolet-visible spectroscopy (UV-Vis). Results showed that the polymer had excellent pH responsiveness and a low critical solution temperature (LCST), which could self-assemble into vesicles with PAA as hydrophilic shell, PDPA as hydrophobic intermediate layer and PNVCL as hydrophilic cavity. Then, the PAA shell layer was crosslinked with disulfide bonds through amide reaction, to improve the structural stability of vesicles and meanwhile introduce the reduction sensitivity. The changes of the particle size, Zeta potential, and morphology of the vesicle under different conditions were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Results showed that the shell-crosslinked vesicles were uniformly sized spherical structure with good pH value and reduction responsiveness. Their drug encapsulation effect and in-vitro release behavior under different pH values and glutathione (GSH) concentrations were studied by UV-Vis and FT-IR. Results showed that the carriers could achieve zoned and co-loading of hydrophobic small molecule drug (doxorubicin (DOX)) and hydrophilic macromolecular protein drug model (bovine serum protein (BSA)). The hydrophobic layer of PDPA and the crosslinked layer of PAA provided dualblockade for drug leakage. The leakage of drugs under normal physiological conditions was low, and the release of DOX and BSA could only be triggered under simulated tumor microenvironment, that is, weak acid and high concentration of GSH conditions. The smart responsive drug carriers constructed in this paper are expected to achieve co-delivery of chemotherapy and biomacromolecule drugs, which have potential application value to the clinical treatment of tumors. [ABSTRACT FROM AUTHOR]

To improve the utilization rate of pesticides and reduce the economic losses and environmental hazards caused by pesticide loss, the self-assembly layer of poly (octadecylsiloxane) (PODS) was prepared by hydrolysis, self-assembly and polycondensation of octadecyltrichlorosilane (OTS) on the surface of rapeseed meal (RSM) with octadecyltrichlorosilane (OTS) and p-aminoazobenzene (AAB) as modifiers. At the same time, AAB with photoisomerism was attached to RSM surface to synthesize RSM-PODS/AAB pesticide carrier with photoresponsiveness. Its structure and composition were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-Vis spectroscopy and contact angle measurement device. The results showed that the loading rate of modified RSM was 21.4% higher than that of original RSM, and the cumulative release rate of pinoxaden was 83% in 72 h in the dark. The cumulative release rate of RSM-PODS/AAB was 95% after UV-Vis irradiation for 4 h and 92% after sunlight irradiation for 6 h. The application results showed that RSM-PODS/AAB loaded with pesticides had good UV-Vis and sunlight controlled release performance. The light responsive lipophilic pesticide carrier could effectively control the drug release behavior through UV-Vis and sunlight response. [ABSTRACT FROM AUTHOR]

The leaching of spent lithium-ion battery (LIBs) cathode materials with non-aqueous systems has received widespread attention. In this paper, a binary non-aqueous system of glycerin(Gly)-formic acid(FA)and a ternary non-aqueous system of Gly-FA-choline chloride (ChCl) were used for the leaching of LiCoO2 cathode materials. The effects of leaching time, leaching temperature and liquid-to-solid ratio conditions on leaching rates were investigated. The results indicated that the addition of ChCl was able to significantly improve the leaching rates of the metals. Under the optimal conditions of time 210 min, temperature 120 °C and liquid-solid ratio 100 mL/g, the ternary non-aqueous system achieved leaching efficiencies of 99.77% and 89.09% for Li and Co respectively, higher than the 67.94% and 67.11% for the binary non-aqueous system. The leachate was analyzed by UV-Vis and FT-IR spectroscopy to reveal the leaching mechanism. The results showed that FA was able to reduce Co3+ to Co2+ in LiCoO2. However, Co2+ was present in different forms in the two non-aqueous systems, where the binary system was present as a hexa-coordination and the ternary system as a tetra-coordination. [ABSTRACT FROM AUTHOR]

There were various problems with chromogenic agent-based UV-Vis spectroscopic detection, such as a large selection range and an insufficient molar absorption coefficient. This study highlighted the research application of UV-Vis spectroscopy technology in industrial heavy metal detection as well as the detection mechanism. Chromogenic agent-based detection techniques were often utilized in product assessment, wastewater monitoring, and industrial production process control. Due to the limitations of UV-Vis spectroscopy, the combination of the UV-Vis spectrum and other stoichiometry technologies will expand its applications to the detection of industrial heavy metals. [ABSTRACT FROM AUTHOR]

The organic semiconductor poly(3-hexylthiophene) (P3HT) film prepared by the spin-coating method is optimized by dichlorobenzene (o-DCB) solvent added with chloroform (CF). The organic electrochemical transistor (OECT) is obtained using the optimized P3HT film as the channel layer and ion gel as the electrolyte layer. The effect of CF on the roughness and molecular order of P3HT film is inverstigated by atomic force microscopy, UV-visible spectroscopy and Raman spectroscopy. The effect of CF optimization on the electrical properties of the material is studied with a semiconductor parametric analyzer. Results show that CF introduction reduces the roughness of P3HT film and improves the order degree of P3HT molecular arrangement. The CF-optimized OECT exhibits significant synaptic excitatory pulse current characteristics under the stimulation of −0.5 V and −1.0 V electric pulses. Compared to the device without CF optimization, the amplitude of conductance regulation is increased by about twice and 16 times, respectively, along with the improved retention performance. The simulation results show that the accuracy of the neural network based on the CF-optimized OECT in recognizing MNIST（Modified National Institute of Standards and Technology） handwritten digits is increased from 73.6% to 92.7%. This device is expected to play an important role in large-scale neuromorphic computing applications. [ABSTRACT FROM AUTHOR]

Monodisperse carbon nanospheres (CNs-APAM) with different APAM incorporation amounts were prepared by an assisted hydrothermal method using glucose, anionic polyacrylamide (APAM) as raw material. The samples were characterized and tested using SEM, FTTR, XRD, TG, and ultraviolet-visible spectrophotometer (UV-vis). The effects of APAM addition on the dispersion and yield of carbon nano spheres (CNs) and the adsorption performance of CNs on methylene blue (MB) with different APAM additions were investigated. Tt was shown that the best dispersion and highest yield of CNs were achieved at the addition of APAM at 1 20 mg, with the yield up to 21.5 %• The adsorption results showed that CNs-APAM had the best adsorption effect on MB with the maximum adsorption amount of 124.26 mg • g-1 when the addition amount of APAM was 1 20 mg, the adsorption time was about 2 h, the concentration of MB solution was 30 mg/L, and the initial pH of the solution was 100. The fitting results of the adsorption model showed that the process of MB adsorption by CNs-APAM was consistent with Langmuir model with quasi-secondary kinetic model. [ABSTRACT FROM AUTHOR]

Flavonoids have good pharmacological activity and are widely used, but the yield of extracted flavonoids is low and the price is high. In order to explore the new technology of artificial synthesis of flavonoids and synthesis of new flavonoids, natural product paeonol was used as the raw material, and alkali catalyzed condensation reaction between m-hydroxybenzaldehyde and paeonol was carried out to construct intermediate product Ⅰ. Then, at high temperature, dimethyl sulfoxide (DMSO) was used as a solvent, and iodine was catalyzed to induce its oxidation and cyclization to obtain the target product Ⅱ. The structure of the product was determined through comprehensive analysis such as UV, IR, elemental analysis, and nuclear magnetic resonance. The changes in UV spectra of product Ⅰ and product Ⅱ in different concentrations of acid, alkali, and salt solutions were investigated and the reasons were analyzed. The results show that product Ⅰ is 2′,3-dihydroxy-4′-methoxychalone, with a yield of 82.2%. Its UV spectrum varies in different concentrations of acid, alkali, and salt solutions, and it could react with low concentrations of NaOH solution. The product could exist stably within 30 minutes and also easily interact with KNO3 solution, resulting in unstable products. Product Ⅱ is 7-methoxy-3′- hydroxyflavone, with a yield of 92. 0% . It can exist stably for a long time in HCl (4.0 mol / L), NaOH, and KNO3 solutions. This synthesis process overcomes the problem of protecting hydroxyl groups in condensation reactions and achieves efficient synthesis of 7- methoxy-3′-hydroxyflavones. Product Ⅰ failed to form a 4-chromone structure, with one phenolic hydroxyl group on each AB ring. Its stability is greatly affected by the environment, especially in alkaline environments. When using product Ⅰ, the storage environment should be controlled, and the pH should not be higher than 7. Product Ⅱ has a stable conjugated structure, which is less affected by the environment and can also exist stably in strong acid environments. This study has guiding and reference value for the production and application of flavonoids. [ABSTRACT FROM AUTHOR]

An indoor simulation test system with a mud (sediment) water mass ratio of about 1:1 and a period of 56 days was adopted. Six concentration gradient test groups, including the control group, were set up to study the change characteristics of total organic carbon (TOC) content in sediments caused by different levels of exogenous phosphorus input. At the same time, UV-Vis absorption spectroscopy was used to study the effect of phosphorus containing substances on the structural changes of dissolved organic matter in sediments. The experimental results showed that the TOC content in the sediment of each experimental group decreased by 3.60%, 7.08%, 8.09%, 9.33% and 11.80% respectively compared with the control group on the 56th day, indicating that the decomposition of TOC in the sediment of the Yangtze Estuary accelerated with the increase of exogenous phosphorus input. During the test period, the maximum humification degree and aromatization degree of dissolved organic matter in sediments were positively correlated with the input of phosphorus. The molecular weight and aromatic ring structure of dissolved organic matter were positively correlated with the input of exogenous phosphorus, indicating that the increase of exogenous phosphorus input could accelerate the change of dissolved organic matter in sediments. With the increase of test time, the humification degree and aromatization degree of dissolved organic matter with different phosphorus levels increased first, and then began to decline; The molecular weight of dissolved organic matter gradually decreased with the increase of time, and the substituents on its aromatic ring substituents were gradually replaced by more active functional groups. It shows that humus is formed during the reduction of organic carbon content in sediments. As humus continues to decompose, the degree of humification decreases, and the degree of humification is the same as that of aromatization. [ABSTRACT FROM AUTHOR]

Chemistry laboratory training is an integral part of chemistry teaching. However, outdated experimental protocols present limitations and can hinder students’ initiative and innate inclination toward exploration. In this study, novel scientific concepts were translated into experimental chemistry teaching. Small fluorescent molecules with aggregation-induced emission and excited-state intramolecular proton transfer properties were prepared using a carbonyl nucleophile addition reaction. The basic photophysical properties of the molecules and their fluorescence response to acid-base stimulation were evaluated experimentally. The non-toxic and non-noxious reagents used for the experiments were refluxed in ethanol for 0.5 h to implement green organic synthesis principles. The experiment was compact and the fluorescence and color changes of the as-synthesized molecules were conspicuous and remarkable. This can stimulate students’ enthusiasm for experimental chemistry. In addition to the basic organic synthesis reaction, this experiment included several modern analysis and characterization methods, such as nuclear magnetic resonance, Fourier-transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy, and fluorescence spectroscopy. We are confident that this intuitive and effective basic experiment can effectively stimulate and cultivate the innate curiosity of students. [ABSTRACT FROM AUTHOR]

One of the most effective methods for improving the storage density of resistive random access memories (RRAMs) is to fabricate 3D vertical stacking devices. By using BP-DDAT(DDAT: S-1-dodecyl-S ′-(α,α′-dimethyl-α′ ′- aceticacid)trithiocarbonate) as a key 2D template and reversible addition-fragmentation chain transfer (RAFT) reagent, a novel poly(N-vinylcarbazole) covalently functionalized black phosphorus derivative (BP-PVK) is successfully synthesized and well-characterized by infrared spectroscopy, X-ray electron spectroscopy and UV-Vis absorption spectroscopy. The environmental stability and solubility of BP nanosheets are greatly improved. Using BP-PVK as active layer, a double-layer vertically stacked RRAM memory device (17×17 stripe array) with a configuration of Al/BP-PVK/Al/BP-PVK/Al is fabricated. The as-fabricated device shows good bistable electrical switching and non-volatile rewritable performance at room temperature, with an ON/OFF current ratio exceeding 10³, higher production yield of the memory devices and structural uniformity. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene) (PEDOT) is used in organic-inorganic heterojunction based ultraviolet (UV) photodetector due to its good environmental stability, high conductivity and special photoelectric characteristics. The commonly used methods for depositing PEDOT films include solution spin coating, electrochemical polymerization, vacuum evaporation and immersion. In this paper, PEDOT film on the surface of fluorine doped tin oxide (FTO) coated glass conductive glass is obtained by solid-state polymerization, using 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) as monomer. The PEDOT film modified FTO was combined with zinc oxide nano arrays (ZnO NRs) modified FTO to fabricate the organic-inorganic heterojunction based UV photodetector, and the performance of UV photodetection ability was studied. The materials were characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier-transfer infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray powder diffractometry (XRD). The photo-responsivity, response speed and stability of the UV photodetector were examined in detail through current-voltag (I-V), current-time (I-t) and Tafel curves at zero bias voltage under UV irradiation (365 nm, 0.32 mW/cm²). Results showed that the PEDOT film had a large flake structure, which was conducive to the good contact of ZnO NRs to build a better p-n heterojunction. Furthermore, the introduction of PEDOT film effectively solved the problems of short carrier life, high recombination rate of hole-electrons and slow light response speed of ZnO NRs. In a word, the PEDOT film enhanced the optoelectronic performance of ZnO NRs, which possessed high responsivity of 15.34 mA/W, fast response time of 0.159 s/0.162 s (rise time/fall time) under UV irradiation (365 nm, 0.32 mW/cm²) and good stability. [ABSTRACT FROM AUTHOR]

CsPbBr3-Cs4 PbBr6 perovskite composite nanocrystals (NCs) were successfully prepared by mechanochemistry method at room temperature, introducing trace amounts of methanol and oleylamine as ligands. The nanocrystals were tested by powder X-ray diffraction (XRD), elemental content analysis (EDS), ultraviolet-visible spectroscopy (UV-Vis), photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). Compared with the samples without methanol, the luminescence intensity of the samples with 0.85 mL methanol increases by 58%, and the quantum yield (PLQY) increases from 11% to 55%. Moreover, the presence of Cs4 PbBr6 in the composite NCs improves the stability of the samples at room temperature. This experiment confirm that the introduction of methanol in the mechanochemistry preparation process could adjust the composition of the complex nanocrystals, thus significantly improving the luminescence intensity and stability of the products, which provides a new idea for the synthesis of luminescent nanocrystals at room temperature. [ABSTRACT FROM AUTHOR]

Two novel stigmasterol derivatives as gelators are synthesized，and named as compounds 1 and 2， respectively. The structure and properties of gels are studied by scanning electron microscopy（SEM），Fourier transform infrared spectroscopy（FT-IR）and UV-Vis spectrophotometer. The results of the gelation properties of compounds 1 and 2 show that they could gelate in DMSO and methanol. Compound 1 also forms a stable gel in DMSO/water mixed solvents at a volume ratio of 9∶1，8∶2，and 7∶3，respectively. In addition，when compounds 1 and 2 are gelated at a mass concentration of 12 mg/mL in DMSO，the gel-sol phase transition temperatures（Tgel）of the two compounds are 51 and 46 ℃，respectively，indicating that the thermal stability of their gelation decreases significantly with the increase of steroidal structural units in the gelator. With the increase of steroid structural units in the gelators，the thermal stability of the gel formation decreases significantly. On this basis，the gel prepared by compound 1 is used as the carrier，and its encapsulation and release in rhodamine B and methylene blue，as well as the anticancer drug doxorubicin are studied by UV-Vis spectroscopy. The results show that the prepared gels could be used as a drug carrier，and the maximum release value reaches 84% in water at 240 min. Furthermore，this study may provide a useful idea for the preparation of stigmasterol derivative gels and its application as a drug carrier in drug delivery. [ABSTRACT FROM AUTHOR]

BACKGROUND: There are differences in the production characteristics, chemical composition, coloration mechanism and formation conditions of green tourmaline from different producing areas. At present, the mineral species and coloration mechanism of Tanzanian green tourmaline have not been solved, which makes it difficult for its scientific identification and quality rating. OBJECTIVES: To study the mineralogical characteristics and coloration mechanism of Tanzanian green tourmaline. METHODS: The mineral component was analyzed by infrared spectroscopy and Raman spectroscopy. Microtexture was characterized by polarized light microscopy. Electron probe microanalyzer, and ultraviolet-visible (UV-Vis) spectroscopy were applied to analyze the chemical composition. RESULTS: The main mineral component of tourmaline in Tanzania was MgO tourmaline, which was characterized by single crystal, small grain, no cleavage, and split development, and can be used as a gemstone. The main chemical component of green tourmaline was SiO2, Al2O3, MgO and B2O3, with average contents of 37.52%, 36.26%, 9.65% and 8.42%, respectively. In addition, it contained a small amount of FeO, Cr2O3 and TiO2. Combined with the absorption spectrum in the ultraviolet region of 440 nm, 600 nm and 680 nm in UV-Vis spectroscopy, it was concluded that the tiny amounts of Cr3+ replacing Al3+ into the crystal lattice was the main cause of the green color. CONCLUSIONS: The mineralogical characteristics and coloration mechanism of green tourmaline in Tanzania was confirmed, which provides a theoretical basis for the scientific identification, further quality evaluation and utilization. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) and tetrabutyl titanate (TBOT) are dissolved in a mixed solvent of N, N'- dimethylformamide (DMF) and acetone to electrospun into a fiber membrane. Then, TBOT contained in the electrospun fiber membrane was reduced to titanium dioxide (TiO2) by a one-step hydrothermal method at 150 °C. The PVDF fiber membrane material with TiO2 grown in situ on the surface and inside of the fiber was obtained. The morphology and structure of TiO2 grown on PVDF fibers in situ were determined by scanning electron microscopy (SEM), thermal gravity (TG), X-ray diffractometer (XRD) and Fourier infrared absorption spectroscopy (FT-IR). Then, the degradation effect of the composite film on the three organic dyes (rhodamine B, methyl orange and methylene blue) was tested by UV-visible spectroscopy. Finally, the gravity-driven method was used to separate the oil-water mixture, and the contact angle of the composite membrane to water and oil was tested to explore the oil-water separation effect of the composite membrane. Results show that the composite membrane has a good degradation effect on organic dyes such as rhodamine B, methyl orange, methylene blue. The composite membrane also has good lipophilic and hydrophobic properties. It is separated by a mixture of carbon tetrachloride and water. The composite membrane can effectively realize oil-water separation, and the oil-water separation efficiency can be as high as 98.2%. [ABSTRACT FROM AUTHOR]

Organic filters in conventional sunscreens generally have poor photo stability and can easily penetrate through stratum corneum and dermis into the blood vessel, thus causing potential health-threatening issues. Polydopamine (PDA) nanoparticles can be formed by self-polymerization of dopamine. Inspired by its excellent anti-ultraviolet, free radical scavenging and adhesion properties, the titanium dioxide (TiO2) precursor is prepared by the sol-gel method and blended with dopamine hydrochloride to prepare PDA-TiO2 hybrid nanoparticles. Infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), thermogravimetric analysis (TGA) and skin penetration experiments were used to characterize the basic structures and properties of nanoparticles. Under the synergistic effect of PDA and TiO2, the particles have highly efficient UV protection. By simply adjusting the reaction material ratio, it was found that the more dopamine content, the better UV absorption effect was obtained, and it showed better UV absorption performance than small particle size PDA. Therefore, PDA-TiO2 (1/10) (m (DA)∶m(TiO2)=1∶10) had the best UV absorption effect. The PDA-TiO2 (1/10) was introduced as the sole active ingredient to formulating sunscreen, whose sun protection factor (SPF) values could reach 33.7, which can meet daily sun protection needs. Most importantly, PDA had good bioadhesion and can effectively prevent the penetration of PDA-TiO2 hybrid nanoparticles. The thickness of the stratum corneum of the human body was about 15—20 μm. Upon comparing the PDA-TiO2 with commercially available benzophenone small molecule sunscreens, it was found that the skin permeability of PDA-TiO2 was significantly reduced. The penetration depth was 9 —17 μm, mainly distributed in the upper and middle parts of the stratum corneum of the skin. It is not easy to enter the human body and will not pose a potential threat to skin health. The commercially available benzophenone sunscreen small molecules had a skin penetration of 18 —35 μm, indicating that they penetrate the stratum corneum to reach the living epidermis and enter the human body. Therefore, the prepared nanoparticles have excellent UV resistance and biocompatibility, ensuring their excellent performance and safe use in sunscreens. [ABSTRACT FROM AUTHOR]

Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the selfassembly of QAC, L-cys and the precursor of nano-zinc oxide, and the size of the hybrid colloidal particles can be controlled by the concentration of nano-zinc oxide precursor. QAC/ZnO hybrid colloidal particles have good ultraviolet shielding property, excellent antioxidant property and low cytotoxicity. Moreover, the photocatalytic activity of the QAC/ZnO hybrid colloidal particles are significantly reduced in comparison with ZnO. It is expected to be used in cosmetics as an ultraviolet absorbent. [ABSTRACT FROM AUTHOR]

Droplets evaporation on plant leaves plays an important role in the utilization of pesticides. Although traditional surfactants can change the evaporation mode or evaporation rate of droplets, they cannot adjust the evaporation process effectively according to external stimuli. In this research, a photo-responsive diacetylene-based cationic surfactant (PCDA-C6-NH3+) was designed and synthesized, where 10,12-pentacosadiynoic acid and protonated terminal amine were used as the photo-responsive motiey and the hydrophilic cation, respectively. The UV light-induced topochemical polymerization of PCDA-C6-NH3+ was studied by UV-Vis spectroscopy. Its surface activity and evaporation behavior before and after UV irradiation were analyzed by static surface tension and dynamic contact angle. The results showed that the aggregation state of PCDA-C6-NH3+ can be regulated by UV light during the droplets evaporation process, because of its topochemical polymerization. This work has provided a new strategy to adjust the evaporation of droplets, which is of great significance for improving the utilization rate of pesticides. [ABSTRACT FROM AUTHOR]

Herein, a comprehensive experiment was developed based on the fabrication and characterization of highmolecular- weight silk peptide functionalized graphene nanosheets (SP-Gr) and its application in electrochemical sensing of dopamine. In this experiment, transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction and UV-Vis spectroscopy were used to characterize SP-Gr nanocomposites. SP-Gr nanocomposites were coated onto a glassy carbon electrode surface to fabricate an electrochemical sensor for determining dopamine. Experimental conditions for dopamine determination were optimized. An effective method was developed for determining dopamine. [ABSTRACT FROM AUTHOR]

BACKGROUND:Akoya pearl is a biomineralized organic gemstone. The mineral composition and microtextural analysis, and the identification method of color formation of this type of pearl are still lacking. OBJECTIVES:To identify natural gray pearls from treated-color gray pearls. METHODS:The spectroscopic and textural characteristics of two kinds of seawater cultured gray pearls with white or gray nucleus were comparatively investigated by optical microscope, Fourier transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy, and X-ray fluorescence spectrometry. RESULTS:The gray pearls with white or gray nucleus had diameters from 5mm to 9mm, the thickness of 300-500μm. The nacreous layer and its corresponding nucleus of the two kinds of gray pearls were composed mainly of biological aragonite, and their corresponding nacreous layers were rich in Sr and poor in Mn. The pearl with the gray nucleus was rich in Mn. The valence state of Mn was increased due to irradiation, resulting in gray of the pearl core and the whole pearl. In general, the pearls with a white nucleus had an obvious reflection band from 300nm to 400nm in the ultraviolet-visible absorption spectra. On the contrary, those pearls with a light or heavy gray nucleus had a reflection band from 400nm to 500nm. CONCLUSIONS:The two types of gray pearls are all marine cultured pearls. The difference of ultraviolet absorption spectra of the two types of pearls can be used as a basis for judging whether the gray pearls are irradiatedly colored. [ABSTRACT FROM AUTHOR]

A comprehensive experiment of sodium dodecyl benzene sulfonate (SDBS) intercalated nickel-titanium layered double hydroxide (NiTi-LDH-SDBS) synthesis and application in dye adsorption is designed. The NiTi-LDH-SDBS with SDBS guest molecule in the interlayer were successfully synthesized, and characterized by X-ray diffraction and infrared spectroscopy. The dye adsorption performance of the intercalation complex and the dye removal rate were quantitatively analyzed by ultraviolet-visible absorption spectroscopy. The results show that the adsorption of methylene blue (MB) on NiTi-LDH-SDBS is better than that of methyl orange (MO), owing to the stronger guest-guest interaction between MB and SDBS. The adsorption behavior of MB on NiTi-LDH-SDBS accords with Langmuir adsorption isotherm and pseudo-second-order equation, the calculated saturated adsorption amount was 181.2 mg/g, which was basically consistent with the experimental measurement of 176.4 mg/g. [ABSTRACT FROM AUTHOR]

A substituted tetraphenyl-porphyrin zinc complex was prepared by using pyrrole, 4-chlorobenzaldehyde, and acetic acid zinc as starting materials. The composition and structure of the complex were characterized by elemental analysis, infrared spectroscopy, ultraviolet-visible spectroscopy and electronic spray mass spectrometry. The composite film material with tetraphenyl-porphyrin zinc complex is prepared based on polyacrylonitrile (PAN) fiber as carrier by electrostatic spinning technology, and its fluorescence property was investigated. The experiment project covers many knowledge points such as synthesis of macrocyclic compounds, column chromatographic separation technology, electrostatic spinning technology and modern instrumental analysis techniques, and has the characteristics of comprehensiveness and operability. It is used in graduate course teaching for the modern chemical experiment technology to cultivate the graduate student’s comprehensive experimental skill and innovation ability. [ABSTRACT FROM AUTHOR]

Objective: To establish a dual wavelength UV-spectrophotometric method for the determination of vitamin E in allantion vitamin E cream. Methods: The UV-visible spectrophotometer was used for content determination of vitamin E.The detection wavelength and reference wavelength were 285 nm and 293.2 nm，respectively.Results：The linear range of vitamin E was 31.96-95.88 μg/ml（r=0.999 9. The average recovery was 100.80%，RSD was 1.21%（n=9）.Conclusion：The method was more accurate，sensitive，specific and reproducible.It could provide the reference for the improvement of the quality standards of allantion vitamin E cream. [ABSTRACT FROM AUTHOR]