bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced ultrasonic imaging property of polyurethane filled with hollow glass beads
Authors: Gao Weining , Lian Rui , Chen Xiaonong , Yan Shentao , Zhang Suqiao , Zhang Guoqiang 
Published: February 2020

AbstractMaterials capable of ultrasonic imaging in vivo are essential for the development of ultrasound visualized interventional catheters. In the present research, hollow glass beads (HGB) were added to polyurethane as ultrasonic image‐enhancing agent to obtain composite with improved ultrasonic visibility within body tissues. The experimental results show that with the increase of the volume percentage of HGB (VHGB) in the composites, the clarity of the ultrasonic images of the composite samples gradually improves. For ultrasonic imaging, a proper VHGB would be 6% to 10%. The particle size (25‐65 μm) of the HGB has almost no effect on the imaging of the composites at the same loading level of the glass beads. The result obtained in the experiments conducted in pig body confirmed that TPU/HGB composite sample could provide significant enhanced ultrasonic imaging compared with pure polyurethane sample and the commercial interventional catheter sample used. Medical safety of the composite was briefly investigated as well by testing the extraction solution of the composite sample.
Bacillus thuringiensis vegetative insecticidal protein family Vip3A and mode of action against pest Lepidoptera
Authors: Chakrabarty Swapan , Jin Minghui , Wu Chao , Chakraborty Panchali , Xiao Yutao 
Published: February 2020

AbstractVip3A proteins are widely used for controlling pest Lepidoptera. Different binding sites with different receptors in the insect midgut membrane and lack of cross‐resistance with crystal (Cry) proteins enhance their applicability, as both single proteins and proteins pyramided with Cry proteins in transgenic Bt crops. Vip3A proteins are effective but there is relatively little information about their structure, function, activation, specificity, and mode of action. In addition, the mechanism of insect resistance to these proteins is unknown. Phylogenetic analysis and multiple sequence alignment showed that Vip3A proteins are genetically distant from Cry proteins. The mode of action and insecticidal activity of Vip3A proteins are discussed in this review. This review also provides detailed information about the Vip3A protein family that may aid in the design of more efficient pest management strategies in response to insect resistance to insecticidal proteins. © 2020 Society of Chemical Industry
On the aspect of plane of appearance of Jahn‐Teller and Renner‐Teller intersections in tetra‐atomic system—A case study with HCNO+
Authors: Mondal Rintu , Mukhopadhyay Debasis 
Published: February 2020

AbstractA search for configuration space with well‐defined topological (Berry) phases corresponding to Jahn‐Teller (JT) conical intersection (CI) and Renner‐Teller (RT) parabolic intersection (PI) in the linear tetra‐atomic molecular system on introduction of bending demonstrates the interesting aspect that these potential intersections may appear in the molecular plane as well as out of the molecular plane. While understanding this aspect is important for following the class of phenomena led by potential intersections, till date, studies on molecular systems, including pairs such as (C2H2+, HCNH) and (N2H2+, HBNH+), have not been able to clarify the issue. The present article includes calculation of nonadiabatic coupling terms involving four low‐lying states of slightly bent HCNO+, a motivated choice of tetra‐atomic with all four different atoms, to study this aspect associated with JT‐CI and RT‐PI in a slightly bent linear system. The plane of appearance of these effects has been advocated to be related to the electronic configuration of the concerned states of the molecular system.
Buried and forgotten—The non‐fluvial characteristics of postglacial rivers
Authors: Hauer Christoph , Pulg Ulrich 
Published: February 2020

Abstract“The systematic analysis and understanding of channel‐forming processes of rivers must be expanded by including semi‐ and non‐fluvial geomorphological processes. Such processes were particularly driven by glaciation during the Pleistocene and led to diamictic non‐fluvial deposits in the post‐glacial valleys. In the Holocene, rivers either covered these deposits with fluvial sediments or incised into them and exposed the non‐fluvial deposits. These processes have strong and so far overlooked implications for the understanding of the genesis, morphology and sediment composition of many rivers – and thus for river utilization, ecology, restoration and management.”
Shaping Giant Membrane Vesicles in 3D‐Printed Protein Hydrogel Cages
Authors: Jia Haiyang , Litschel Thomas , Heymann Michael , Eto Hiromune , Franquelim Henri G. , Schwille Petra 
Published: February 2020

AbstractGiant unilamellar phospholipid vesicles are attractive starting points for constructing minimal living cells from the bottom‐up. Their membranes are compatible with many physiologically functional modules and act as selective barriers, while retaining a high morphological flexibility. However, their spherical shape renders them rather inappropriate to study phenomena that are based on distinct cell shape and polarity, such as cell division. Here, a microscale device based on 3D printed protein hydrogel is introduced to induce pH‐stimulated reversible shape changes in trapped vesicles without compromising their free‐standing membranes. Deformations of spheres to at least twice their aspect ratio, but also toward unusual quadratic or triangular shapes can be accomplished. Mechanical force induced by the cages to phase‐separated membrane vesicles can lead to spontaneous shape deformations, from the recurrent formation of dumbbells with curved necks between domains to full budding of membrane domains as separate vesicles. Moreover, shape‐tunable vesicles are particularly desirable when reconstituting geometry‐sensitive protein networks, such as reaction‐diffusion systems. In particular, vesicle shape changes allow to switch between different modes of self‐organized protein oscillations within, and thus, to influence reaction networks directly by external mechanical cues.
Chemical Information Exchange in Organized Protocells and Natural Cell Assemblies with Controllable Spatial Positions
Authors: Wang Xuejing , Tian Liangfei , Ren Yongshuo , Zhao Zhongyang , Du Hang , Zhang Zhizhou , Drinkwater Bruce W. , Mann Stephen , Han Xiaojun 
Published: February 2020

AbstractAn ultrasound‐based platform is established to prepare homogenous arrays of giant unilamellar vesicles (GUVs) or red blood cell (RBCs), or hybrid assemblies of GUV/RBCs. Due to different responses to the modulation of the acoustic standing wave pressure field between the GUVs and RBCs, various types of protocell/natural cell hybrid assemblies are prepared with the ability to undergo reversible dynamic reconfigurations from vertical to horizontal alignments, or from 1D to 2D arrangements. A two‐step enzymatic cascade reaction between transmitter glucose oxidase‐containing GUVs and peroxidase‐active receiver RBCs is used to implement chemical signal transduction in the different hybrid micro‐arrays. Taken together, the obtained results suggest that the ultrasound‐based micro‐array technology can be used as an alternative platform to explore chemical communication pathways between protocells and natural cells, providing new opportunities for bottom‐up synthetic biology.
Chemical constituents of Chirita halongensis Kiew & T.H.Nguyen collected in Ha Long Bay, Quang Ninh province, Viet Nam
Authors: Tam Khieu Thi , Anh Nguyen Thi Hoang , Van Tuan Nguyen , Thien Dao Duc , Tam Nguyen Thanh , Quan Tran Duc , Thang Le Quoc , Thuy Trinh Thi , Van Sung Tran 
Published: February 2020

AbstractThe chemical investigation of the whole plant of Chirita halongensis Kiew & T.H.Nguyen collected in Ha Long bay, Quang Ninh province led to the isolation and structural elucidation of nine compounds, including one anthraquinone, three triterpenoids and five phenylethanoid glycosides. Three of them: oleanolic acid, decaffeoylacteoside and β‐hydroxy acteoside have been found for the first time in Chirita genus. Their structures were elucidated by mass, NMR spectroscopies and comparison with published data. It is the first report on chemical constituents of this species.
Properties of poly(lactic acid) plasticized by epoxidized rubber seed oil
Authors: Thuy Nguyen Thi , Duc Vu Minh , Liem Nguyen Thanh 
Published: February 2020

AbstractIn this study, epoxidized rubber seed oil (EeRSO) was utilized as a plasticizer for polylactic acid (PLA) using a melt blending method at five weight ratios of PLA/EeRSO, 100/0, 97.5/2.5, 95/5, 92.5/7.5, and 90/10, respectively. The plasticization of PLA with EeRSO lowered the Tg as well as cold‐crystallization temperature. The tensile properties demonstrated that the addition of EeRSO to PLA led to a strong increase in elongation at break and tensile toughness, but a decrease in tensile strength. The impact strength of PLA was improved by 103%, with the presence of 7.5 wt.% EeRSO. The SEM image of the plasticized PLA showed good compatible morphology without voids. The initial decomposition temperature grew from 261.8 to 308.83°C and the weight loss at 384°C of PLA reduced from 91.2 to 81.5 % with the presence of 5 wt.% EeRSO. Based on the results of this study, EeRSO may be used as an environmentally friendly plasticizer that can improve the overall properties of PLA.
Synthesis and characteristics of Mg‐Ni‐Al‐CO3 hydrotalcites for styrene oxidation
Authors: Huyen Le Thi Kim , Dat Nguyen Tien , Thao Nguyen Tien 
Published: February 2020

AbstractMg‐Ni‐Al‐CO3 hydrotalcite‐like material was synthesized by coprecipitation method at a certain pH. The synthesized solids have been characterized by physical techniques, namely XRD, IR, TEM, and EDS. All synthesized samples showed a well‐defined hydrotalcite structure with the presence of nickel(II) ions in Mg‐Al hydroxide lattice. The Mg‐Ni‐Al‐CO3 catalyst has been tested for the oxidation of styrene with aqueous hydrogen peroxide solution and showed a good catalytic activity in the formation of benzaldehyde. Styrene conversion is in the range of 20‐85 % with the high selectivity to benzaldehyde at 50‐80°C, 4 hours.
A facile and fast solution chemistry synthesis of porous ZnO nanoparticles for high efficiency photodegradation of tartrazine
Authors: Tu Vu Anh , Tuan Vu Anh 
Published: February 2020

AbstractIn this paper, we developed a facile and fast method to prepare porous ZnO nanoparticles as an excellent photocatalyst by a chemical route using citrate as capping agent for the degradation of tartrazine from aqueous solution. For comparison, ZnO rods and flowers were prepared and their photocatalytic ability also was evaluated. The as‐synthesized ZnO samples were characterized by XRD, SEM, and N2 adsorption/desorption. The XRD results showed that as‐prepared ZnO samples were highly crystalline with the hexagonal wurtzite structure. The morphological results revealed that the average size of ZnO nanoparticles was approximately 30‐40 nm. Whereas, ZnO rods had the length of 600 nm and the diameter of 200 nm and ZnO flowers were formed by a lot of nanosheets with an average thickness of 20 nm. The surface area and pore volume of porous ZnO nanoparticle samples were higher than those of flowers and rods. As the expectation, ZnO nanoparticles exhibited the highest degradation rate and efficiency of tartrazine under UV irradiation. The excellent photocatalytic activity of ZnO nanoparticles may be attributed to its surface area and pore volume. In addition, ZnO nanoparticles exhibited a good recycling performance after three cycles of use.
Deeper insights into geometric, spectroscopic and electronic properties of the neutral Au16 cluster
Authors: Nhat Pham Vu 
Published: February 2020

AbstractDensity‐functional calculations are carried out to explore more intensely on geometric, spectroscopic and electronic properties of the neutral Au16. Computed results show that the cluster does not form a hollow cage structure as in its anionic state but prefers a compact structure, giving rise from the cuboctahedron Au12 capped with four gold atoms on triangular faces. The ionization energies for lower‐lying isomers are also computed and compared with available experimental values. Although several isomers are predicted to be very similar in energy, the corresponding vibrational signatures are so distinctive that could be used as a fingerprint signal to identify their geometrical structures. In addition, the electronic and atomic structures of this system can be understood in terms of the phenomenological shell model.
Naturally occurring marine α,β‐epoxy steroids: Origin and biological activities
Authors: Dembitsky Valery M. , Gloriozova Tatyana A. , Poroikov Vladimir V. 
Published: February 2020

AbstractThe present review describes the biological activities of more than 100 marine α,β‐epoxy steroids. These steroids have been isolated from marine invertebrates including, sponges, starfish, soft corals and nudibranch (Mollusca). We used the computer program PASS and based on structure‐activity relationships (SAR), which contains more than one million chemical compounds and more than 8,000 biological activities. The most frequently predicted activities are anti‐neoplastic, anti‐inflammatory, anti‐fungal and other activities are identified with a certainty of 76 to 94 percent. The main activities for different groups of steroids differ significantly.
The theoretical evaluation of the poly(3,4‐dimetylpyrrole) cathodic electrodeposition assisted by manganate ions
Authors: Tkach Volodymyr V. , Storoshchuk Nataliia M. , Romaniv Lyudmyla V. , De Oliveira Sílvio C. , Luganska Olga V. , Gala Hélder Briosae , Tchikuala Emílio Figueira , Yagodynets Petro I. 
Published: February 2020

AbstractThe theoretical description of poly(3,4‐dimethylpyrrole) cathodic electrodeposition in alkaline media has been reported for the first time. The electrochemical deposition of conducting polymer on cathode is realized by in situ formation of manganate‐ions (MnO42‐) as oxidizing agents, and the proper polymer may be doped by hypomanagate, ions (MnO43‐). The stable steady‐state in this system was established rapidly and efficiently, and the polymer surface has to be well developed. No electrochemical instabilities, typical for anodic direct electropolymerization, was observed.
A study on structure and property of two complexes involving platinum(II), eugenol and 8‐hydroxyquinoline derivatives
Authors: Mai Truong Thi Cam , Tu Phan Dang Cam , Chi Nguyen Thi Thanh , Trung Nguyen Tien 
Published: February 2020

AbstractStable structures of complexes formed by the interaction of [PtCl3(Eug)]‐ with either 5,7‐dichloro‐8‐hydroxyquinoline or 5‐nitro‐8‐hydroxyquinoline are determined and compared to the experimental results. Interaction energies and variation of Gibbs free energies, AIM and MEP analysis are carried out at B3LYP/LanL2DZ level of theory to explore characteristics of the complexes and the Pt∙∙∙X (X = N, O) contacts. The obtained results show that charge‐transfer interaction plays a significant role in stabilizing of the examined complexes. It is remarkable that the calculated IR spectra of the examined complexes are well matched with those of the experimental results.
Serratene‐type triterpenoids from Lycopodium cernuum
Authors: Dien Pham Huu , Thao Nguyen Thi , Hai Nguyen Thi , Linh Le Thi Khanh , Quang Dang Ngoc , Nam Bui Tuan , Tung Nguyen Quang 
Published: February 2020

AbstractFour metabolites, serrat‐14‐en‐3β,21β‐diol (1), serrat‐14‐en‐3β,21α‐diol (2), 3β,21β‐dihydroxyserrat‐14‐en‐21‐yl acetate (3), and nonacosanol (4) were isolated from the aerial parts of Lycopodium cernuum plant, collected in Hoang Su Phi Dist., Ha Giang province. Their structures were elucidated by various spectroscopic analyses.
Natural sulphur‐containing steroids: Origin and biological activities
Authors: Dembitsky Valery M. , Savidov Nick , Gloriozova Tatyana A. 
Published: February 2020

AbstractThe present review describes the distribution and biological activities of natural sulphur containing steroids (SCS). The structures and predicted biological activities of SCS are presented in the proposed review. Comparatively a small amount of SCS were found in living organisms, but a very large variety of these lipid molecules were found in geological samples and marine sediments. About fifty steroids showed antineoplastic and antipsiomatic activities with a confidence of 72 to 94 %, and some of them can be used as antidiuretic, antiseborrheic, and anesthetic agents. The presented materials are interesting both for chemists and pharmacologists, as well as specialists from the field of sports medicine, bodybuilding, and pharmaceutical industry.
Removal of Cd2+ by hydroxyapatite adsorption granule from aqueous solution
Authors: Duyen Le Thi , Thao Le Thi Phuong , Hai Do Thi , Dung Pham Tien , Nam Pham Thi , Thom Nguyen Thi , Hong Cao Thi , Linh Cao Thuy , Thanh Dinh Thi Mai 
Published: February 2020

AbstractHydroxyapatite (HAp) adsorption granules with average size of 2 × 10 mm was fabricated from HAp powder and polyvinyl alcohol (PVA) additive by sintering for removing of Cd2+ ions from aqueous solution. The effect of some factors on the Cd2+ adsorption efficiency and capacity was investigated. The removal efficiency and capacity reached 86.5 % and 4.33 mg/g, respectively, at condition: HAp granule mass of 0.3 g, initial Cd2+ concentration of 30 mg/L, contact time of 40 minutes and pH 0 of 5.7 at 30°C. The experimental data was described by Langmuir and Freundlich isotherm models; pseudo‐first order and pseudo‐second order kinetic equations.
Establishment of a chromatographic profile and analytical method for determination of key flavonoids in extract of Ginkgo biloba's leaf
Authors: Duy Huynh Khanh 
Published: February 2020

AbstractFrom extraction of leaves of Ginkgo biloba, quercetin, isorhamnetin and kaempferol were successfully isolated, purified and characterized. The studies on Ginkgo biloba leaves extract allowed to establish a chromatographic profile in which peaks of quercetin, isorhamnetin and kaempferol were chosen as markers. An analytical method to identify the authenticity of Ginkgo biloba extract and determine quantitatively content of these valuable compounds in Ginkgo biloba extract and their related products were successfully established and validated against requirements of AOAC and FDA Guidelines. Although the matrices of these samples were rather complicated, the method showed a good application in qualitative and quantitative determination of quercetin, isorhamnetin and kaempferol in two pharmaceutical products containing extract of Ginkgo biloba. As a result, the method of isolation, purification of quercetin, isorhamnetin and kaempferol from leaves extract of Ginkgo biloba as well as the chromatographic fingerprint and the validated analytical method for qualitative and quantitative determination of these flavonoid compounds in extract of Ginkgo biloba could be considered as a starting point for a corresponding monograph in Vietnamese Pharmacopeia.
Protective effect of pancreatic β‐cells MIN6 by some medicinal plants in the Mekong Delta
Authors: Bach Le Thi , Dung Le Tien , Tuan Nguyen Trong , Phuong Nguyen Thanh , Kestemont Patrick , Quetin‐Leclercq Joëlle , Hue Bui Thi Buu 
Published: February 2020

AbstractEndoplasmic reticulum (ER) stress plays an important role in the pathogenesis of diabetes, contributing to pancreatic β‐cell loss and insulin resistance in type 2 diabetes mellitus (T2DM). In this study, the effect of ethanol extracts of Euphorbia hirta L. (Eup), Phyllanthus amarus L. (Phy), Mimosa pudica L. (Mim), Psidium guajava L. (Psi) and Azadirachta indica A. Juss (Aza) collected in the Mekong Delta on ER stress‐induced apoptosis in mouse β‐cell lines was investigated. The results showed that, among tested extracts, Aza and Eup extracts gave the strongest cell‐protective effect improving cell viability to 76 % and 69 % at the dose of 0.1 mg/mL, respectively. These results indicated that Aza and Eup possess the potential to be developed as novel drugs against T2DM.
Thermal decomposition behavior and shelf‐life of polymer‐bonded explosives and hexogen ‐ An experimental study
Authors: Toan Nguyen Trung , Nhan Phan Duc , Hung Duong Cong , Phuong Vo Hoang 
Published: February 2020

AbstractThe kinetic parameters of thermal decomposition reactions are important in predicting the potential of energetic material systems for the thermal explosion. In this study, the thermal decomposition behaviors of three polymer‐bonded explosive samples based on hexogen and nitrocellulose were evaluated and compared to the hexogen sample. The results show that the binder based on nitrocellulose has negatively affected on the thermal stability of polymer‐bonded explosives. The activation energy of the polymer‐bonded explosive was reduced by approximate 25 % compared to that of hexogen. Moreover, while hexogen exhibited an estimated shelf‐life of 70 years, the polymer‐bonded explosives could remain their safety and explosion properties for only around 45 years. Finally, increasing the nitrocellulose content from 3.75 to 6.67 wt.% reduced the thermal stability and shelf‐life of the polymer‐bonded explosive.
Study on the synthesis of Exemestane
Authors: Tuan Cao Duc , Kim Loan Vu Thi , Trung Trinh Hien , Van Hung Nguyen , Van Thuc Pham 
Published: February 2020

AbstractExemestane, a 3rd‐generation aromatase inhibitor, has been approved by FDA for the treatment of advanced breast cancer in postmenopausal women since 1995 and its patent was expired in 2015. Since the approval, Exemestane has been widely used in breast cancer patients and is shown to have good clinical effects. There are several published synthesis methods of Exemestane but there is not any such report in Viet Nam. Herein, we describe the two‐step method for the synthesis of Exemestane from the commercial available compound, androst‐4‐ene‐3,17‐dione. The total yield of the synthesized Exemestane is 27.12 %. The structure of Exemestane and intermediate products were elucidated by MS and NMR spectroscopies.
Ozonation process and water disinfection
Authors: Nghi Nguyen Hoang , Cuong Le Cao , Dieu Tran Vinh , Ngu Tu , Oanh Doan Thi Yen 
Published: February 2020

AbstractAs commonly known, ozone is a highly effective disinfectant for both aqueous and gaseous media. It works through oxidation. Dissolved ozone causes the increases of the redox potential ORP of water. During the ozonenation process, the time‐dependent redox potential ORP of water depends strongly on the density of microbes in it. By analyzing the time‐dependent redox potential, it is possible to measure and calculate the parameters such as the oxidizing rate, the maximal redox potential ORPmax etc. of the ozonated water. These parameters of water reflect the microbiological pollution level of water. Ozonated water having a certain ORP level obtains disinfecting ability. Bacteriological analysis of the water samples after ozonation show that total coliform and E. coli bacteria were fully removed after a few minutes at ORP of 800 mV.