bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurring outburst floods from drained lakes: an emerging Arctic hazard
Authors: Arp Christopher D , Jones Benjamin M , Hinkel Kenneth M , Kane Douglas L , Whitman Matthew S , Kemnitz Richard
Published: February 2020

New development in regions with rapidly changing climates may experience unforeseen hazards. Thermokarst lakes (bodies of freshwater that collect in depressions formed by thawing permafrost) cover 20% of Arctic lowlands and are naturally prone to causing catastrophic flooding. Cumulative lake drainage over time has resulted in up to 60% landscape coverage by drained thermokarst lake basins (DTLBs). Although the impacts of lake drainage on ecosystems and infrastructure have long been considered a potential hazard, these occurrences are usually viewed as one‐time events. However, recent observations in northern Alaska highlight a previously unrecognized threat: annually recurring snow‐dam outburst floods from DTLBs. Each winter, blowing snow fills DTLB drainage gullies, impounding meltwater in the spring and – upon snow‐dam failure – releasing downstream floods. Data collected from 14 DTLBs in Alaska reveal a wide range in flood peaks, many of which exceed river flood events, providing a missing link in Arctic ecosystem hydrology. Projected snowier winters may result in even larger snow‐dam outbursts from DTLBs, adding uncertainty to future risk assessments. If climate change also drives enhanced lake drainage, we predict even more sporadic and higher magnitude floods, with implications for downstream ecosystems and human infrastructure as development pushes into the Arctic lowlands.
On numerical diffusion of simplified lattice Boltzmann method
Authors: Chen Zhen , Shu Chang
Published: February 2020

In this article, we analyze the numerical diffusion in the recently developed simplified lattice Boltzmann method (SLBM) and propose amending strategies towards lower numerical diffusion. It is noted that, in the original SLBM, the intermediate flow properties are utilized to evaluate the nonequilibrium distribution function, which may bring in excessive numerical diffusion. In the revised scheme, this evaluation strategy is nurtured by using the corrected flow properties to calculate the nonequilibrium distribution function. In the meantime, the numerically evaluated nonequilibrium distribution function only approximately fulfills the conservation relationship in the second order of accuracy. Although such approximation does not violate the global order of accuracy, offsetting the extra error would contribute to reducing the numerical diffusion. After implementing the proposed amending strategies, the revised SLBM (RSLBM) is validated through three numerical examples. The results indicate that RSLBM bears comparable order of accuracy as the original SLBM but shows lower numerical error on the same mesh size. And the reduced numerical error facilitates recovery of delicate flow structures. The proposed RSLBM can be flexibly implemented on nonuniform or body‐fitted meshes, and in three‐dimensional simulations.
Using ovarian and brain cell culture from the Mullet, Liza klunzingeri, to assess the inhibitory effects of benzo[a]pyrene on aromatase activity
Authors: Sheibani Zahra , Salamat Negin , Movahedinia AbdolAli , Hashemitabar Mahmoud , Bayati Vahid
Published: February 2020

We assessed the toxic effects of benzo[a]pyrene (BaP) on cell viability, aromatase (Aro) activity and steroid production using ovarian and brain cell cultures obtained from Mullet, Liza klunzingeri. The brain and ovary were minced and digested, and the cells were suspended in Leibovitz's L‐15 medium supplemented with 15% and 20% fetal bovine serum. The cell suspensions were seeded on 25‐cm2 cell‐culture flasks at 1 × 106 cells/mL and incubated at 25 °C for 2 weeks. A BaP concentration of 10−5 mol/L was accepted as the half‐maximal inhibitory concentration. Ovarian and brain cells were exposed to different concentrations of BaP [0 (control), 10−6, 2 × 10−6, 3 × 10−6 mol/L] and incubated at 30 °C. At different sampling times (0, 12, 24 and 48 h) 40 ng/105 cells of 1,4,6‐androstatriene‐3,17‐dione (ATD) was added to each well. Aro activity, 17β‐estradiol (E2) and ATD production were determined. The sensitivity of the cultivated ovarian and brain cells to BaP increased dose dependently. BaP was a potent inhibitor of Aro activity at 2 × 10−6 and 3 × 10−6 mol/L, both in the cultivated brain and ovarian cells at different sampling times, with 10−6 mol/L BaP found to be the least potent Aro inhibitor. E2 production decreased from cultivated ovarian and brain cells treated by different concentrations of BaP. In conclusion, BaP is able to change the activity of Aro and disrupt the biosynthesis of estrogens, and thus affects reproduction in fish.
Interleukin‐4 administration improves muscle function, adult myogenesis, and lifespan of colon carcinoma‐bearing mice
Authors: Costamagna Domiziana , Duelen Robin , Penna Fabio , Neumann Detlef , Costelli Paola , Sampaolesi Maurilio
Published: February 2020

Background

Anorexia, body wasting, inflammation, muscle, and adipose tissue loss are hallmarks of cancer cachexia, a syndrome that affects the majority of cancer patients, impairing their ability to endure chemotherapeutic therapies and reducing their lifespan. In the last 10 years, alterations of protein turnover and impairment of adult myogenesis have been proposed as major contributing factors.

Methods

Muscle stem cells, including satellite cells, mesoangioblasts, and fibroadipogenic progenitors, were isolated and characterized from C26 colon carcinoma‐bearing (C26) mice. Circulating levels of interleukin‐4/13 (IL4/IL13) were analysed by ELISA, and the effects of IL4 on muscle mass and function, protein synthesis, muscle regeneration, and myogenic progenitor cell number were analysed at both functional (treadmill and grip test) and molecular levels (qRT–PCR, immunofluorescence analysis, surface sensing of translation, and western blot). The Kaplan–Meier test was used to analyse the survival curve of IL4‐treated and IL4‐untreated C26 mice.

Results

The administration of IL4 to C26 mice rescued muscle mass by increasing protein synthesis. The IL4 treatment improved performances and prolonged survival of C26 mice. IL4 administration re‐established both number and function of satellite cells and fibroadipogenic progenitors without affecting mesoangioblasts in C26 mice, rescuing myogenesis. Upon IL4 treatment, a high number of cytotoxic lymphocytes and type II macrophages were observed with a subsequent increase in necrotic areas of C26 tumours.

Conclusions

The results here presented shed new light on IL4 signalling during muscle wasting and early stages of muscle regeneration that explain the beneficial effect observed in IL4‐treated C26 mice. These findings might aid to develop therapeutic approaches to improve mobility and quality of life in cachectic patients.
Methanogenesis of raw cheese whey: pH and substrate–inoculum ratio evaluation at mesophyll temperature range
Authors: Flores‐Mendoza Ana P , Hernández‐García Héctor , Cocotle‐Ronzón Yolanda , Hernandez‐Martinez Eliseo
Published: February 2020

BACKGROUND

Cheese whey is a byproduct of the dairy industry, which is characterized by its high organic matter content, so its valorization by anaerobic digestion (AD) requires a pretreatment or a dilution that allows high values of degradability. However, this increases the cost and duration of whey treatment. In this paper, a study on the viability of anaerobic treatment of a type of crude whey is presented. For it, the effect of pH, substrate–inoculum ratio (S:I) and its interaction during mesophilic AD of raw cheese whey were evaluated. The interactions of the parameters were analyzed by response surface analysis.

RESULTS

The results showed that in the mesophilic temperature range, the pH most suitable for AD of whey is slightly alkaline (pH = 8). Production and methane yield were improved, increasing the proportion of raw whey, which means that it is possible to operate with high organic loading rate, maintaining adequate operation conditions (pH = 8, T = 40 °C). The best performance of the digester reached 7.1 LCH4 Lwhey−1, and a specific methanogenic activity of 1.15 gCOD gTVSi−1 day−1.

CONCLUSION

It is possible to use raw cheese whey to produce methane. The alkaline pH and high S:I ratio improved the methane yield and promote methanogenic activity. Intermediate compounds (volatile fatty acids, NH3 and/or H2S) accumulated during the AD operation, which could have influenced the reactor performance; hence, further study is advisable to elucidate their effect on the global process. © 2020 Society of Chemical Industry
Quality consistency evaluation of commercial transfer factor injections by chromatographic fingerprint combined with multivariate statistical analysis
Authors: Huang Qing , Qian Hanyu , Feng Dong , Wang Yao , Luo Nan , Lu Suya , Shi Qingshui , Zhang Mei , Lu Yihong , Tan Li
Published: February 2020

The current quality control methods relying mainly on chromogenic reaction can hardly ensure the quality and safety of the biochemical drug with complex chemical composition. Therefore, a chromatographic fingerprint method was developed for the quality evaluation of a multicomponent biochemical drug, transfer factor injection. High‐performance liquid chromatography fingerprint was measured by using a C18 column (250 × 4.6 mm, 5 µm) with a mobile phase composed of 0.1% trifluoroacetic acid–water and 0.085% trifluoroacetic acid–acetonitrile under gradient elution. The developed method was validated and was subsequently applied to 57 batches of commercial products which were sampled by National Drug Assessment Program. High‐resolution mass spectrometry analysis was performed on characteristic peaks of fingerprints, and a series of amino acids, nucleosides, and deoxynucleosides were identified. In the fingerprint assessments, principal component analysis and Hotelling T2 analysis yielded the best results. The results generally indicated that there was a significant difference among products of batch‐to‐batch or from different manufacturers. Abnormal samples and its discriminatory components were also explored. In summary, the established fingerprinting method with multivariate statistical analysis could offer an efficient, reliable, and practical approach for quality consistency evaluation of transfer factor injection, providing a reference for the quality control of other multicomponent biochemical drugs.
Fetal Pancake Kidney
Authors: Perlman Sharon , Borovitz Yael , Bar‐Adon Sonya , Dekel Benjamin , Achiron Reuven , Gilboa Yinon
Published: February 2020

Bilateral failure of the kidneys to ascend during embryonic life may lead to fusion of the two renal masses, resulting in a round mass known as pancake kidney. Reviewing the literature, we did not encounter any reports of prenatal diagnosis of pancake kidneys. We present 6 cases of a pancake kidney diagnosed prenatally. Extrarenal associated anomalies included an aberrant right subclavian artery, nonvisualization of the uterus, consistent with Mayer‐Rokitansky‐Küster‐Hauser syndrome, and a sequence of early‐onset growth restriction, hypospadias, and syndactyly, suspected as Smith‐Lemli‐Opitz syndrome. On postnatal follow‐up, all infants had a normal renal outcome.
The Bergman kernel for the Vekua equation
Authors: Campos Hugo M. , Kravchenko Vladislav V.
Published: February 2020

The paper extends some well‐known results for analytic functions onto solutions of the Vekua equation
regarding the existence and construction of the Bergman kernel and of the corresponding Bergman projection operator.
Regulation of Adipocyte and Macrophage Functions by mTORC1 and 2 in Metabolic Diseases
Authors: Festuccia William T.
Published: February 2020

Scope

Evidence gathered in the last decades suggests that lipotoxicity and inflammation are the main factors connecting adipose tissue dysfunction to the development of metabolic diseases such as insulin resistance, nonalcoholic fatty liver disease (NAFLD), cardiovascular disease, and certain types of cancer, among others. The mechanistic target of rapamycin (mTOR) is a serine threonine kinase that functions as the catalytic entity of two multiprotein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). These complexes are important components of signaling pathways activated by nutrients, growth factors, and inflammatory mediators and are therefore directly involved in the regulation of adipocyte and macrophage metabolism and function.

Methods and Results

In this article, studies that evaluate the involvement of mTORC1 and 2 in the regulation of macrophage and adipocyte function and their implication in the development of metabolic‐disease‐associated adipose tissue dysfunction are reviewed.

Conclusion

In adipocytes, optimal levels of mTORC1 activity are required for its pro‐lipogenic actions, while in macrophages, mTORC1 regulates features of both M1 and M2 polarization. mTORC2, on the other hand, promotes glucose uptake and de novo lipogenesis in adipocytes and counteracts macrophage inflammatory response.
A 0.5 nJ/b 60 GHz ultra wideband transmitter for short range wireless sensor network applications
Authors: Jin Ling , Rolland Nathalie
Published: February 2020

A novel monolithic microwave integrated circuit (MMIC) design of ultra wide band (UWB) transmitter at 60 GHz with simple architecture and high‐range resolution ability is presented in this paper. Implemented with 0.1 μm 100 GHz GaAs positive channel high electron mobility transistor (PHEMT) technology offered by OMMIC, the transmitter comprises a millimeter wave oscillator, a buffer amplifier (BA), a medium power amplifier (MPA) and two UWB Pulse Generators (UWBPG). For the sake of the goal on reducing the entire transmitter consumption, the oscillator is controlled by one UWBPG and another UWBPG drives the BA and MPA simultaneously. The transmitter has infinite isolation level to minimize the interference with neighboring devices. For a pulse repetitive time of 5 ns, pulse width of 500 ps and supply voltage of 3 V, the transmitter consumes only 101 mW and has a peak transmit power of 9.2 dBm corresponding to 0.5 nJ per pulse energy consumption, which is suitable for future short range wireless sensor network (WSN) applications.
Detection and recognition of a ground moving target under random dynamic conditions
Authors: Zhang Xiaoqian , Li Hanshan
Published: February 2020

The infrared radiation characteristic of ground moving targets under random dynamic conditions is an important research hotspot to study for the detection performance of the airborne photoelectric detection system. This paper studies the detection mechanism of the airborne photoelectric detection system to a ground moving target and analyzes the relevant factors that affect the infrared radiation characteristics of ground moving targets. Based on spectral radiation theory, establishes the infrared radiation illumination function of a ground moving target under a complex background environment, combines the rotation relationship matrix between ground moving target and airborne photoelectric detection system, and derives the new calculation model of the signal‐to‐noise ratio under the Fraunhofer diffraction effect. The experimental results showed that the infrared radiation characteristics of the ground moving target are affected by detection time and photoelectric detector's wavelength, which verifies the spatial position relationship between the ground moving target and the airborne photoelectric detection system also determines the size of the output signal of the photoelectric detector. To effectively improve the infrared radiation characteristics of the ground moving target, the appropriate wavelength of the photoelectric detector changes the flight attitude and velocity of the carrier aircraft, which can improve the infrared radiation characteristics of ground the moving target in the detection process.
A multicenter, randomized trial comparing pelvic organ prolapse surgical treatment with native tissue and synthetic mesh: A 5‐year follow‐up study
Authors: da Silveira Simone dos Reis B. , Auge Antomio PF. , Jarmy‐Dibella Zsuzsanna IK. , Margarido Paulo FR. , Carramao Silvia , Alves Rodrigues Claudinei , Doumouchtsis Stergios K. , Chada Baracat Edmund , Milhem Haddad Jorge
Published: February 2020

Introduction

The aim of this study was to compare long‐term outcomes in patients who underwent either native tissue repair or monofilament macroporous polypropylene mesh.

Methods

This multicenter, randomized trial included—at the end of 5 years follow‐up—122 women with severe pelvic organ prolapse, who were randomly assigned to undergo surgical treatment using native tissue repair (native tissue group, n = 59) or synthetic mesh repair (mesh group, n = 63). Cure criterion was when pelvic organ prolapse‐quantification (POP‐Q) point was ≤0. Quality of life was assessed using the prolapse quality‐of‐life questionnaire and sexual function with the quality of sexual function.

Results

Groups were homogeneous preoperatively with the exception of the previous pelvic surgery variable, which was higher in mesh (P = .019). Cure rate was significantly better for mesh group in the anterior compartment (P = .002) and in the combination of all compartments (P = .001). Native tissue group was significantly better when there was prolapse in the posterior and apical compartment (P = .031). In the quality of life analysis, mesh group showed a significant improvement compared with native tissue group (P = .004). Complications were significantly higher in mesh and recurrence in native tissue. Regarding the reoperation rate, there was no difference between groups, but native tissue had a higher reoperation rate due to recurrence (P = .031).

Conclusions

Outcomes in women with severe POP were better with mesh use than native tissue repair, both in the anterior compartment and in the multicompartmental prolapse after 5‐year follow‐up. Complications were more common in the mesh group and recurrences were more frequent in the native tissue group.
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

Materials 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

Vip3A 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
Characterization of (Boc‐Cys/Sec‐NHMe)2 and (Boc‐Cys/Sec‐OMe)2: Evidence of local conformational difference between disulfide and diselenide
Authors: Dolle Ashwini , Reddy K. Kasi Amarnath , Gunaga Shubha Shridhar , Krishnamurthy Kiran , Senapati Dillip Kumar , Rana Abhijit , Sindogi Kishorkumar , Biswal Himansu S. , Raghothama Srinivasarao , Gowd Konkallu Hanumae
Published: February 2020

Conformations of disulfide and diselenide were compared in (Boc‐Cys/Sec‐NHMe)2 and (Boc‐Cys/Sec‐OMe)2 using X‐ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, density functional theory (DFT), and circular dichroism (CD) spectroscopy. Conformations of disulfide/diselenide in polypeptides are defined based on the sign of side chain torsion angle χ3 (–CH2–S/Se–S/Se–CH2–); negative indicates left‐handed and positive indicates right‐handed orientation. In the crystals of (Boc‐Cys‐OMe)2 and (Boc‐Sec‐OMe)2, the disulfide exhibits a left‐handed and the diselenide a right‐handed orientation. Characterization of cystine and selenocystine derivatives in solution using 1H‐NMR, natural abundant 77Se NMR, 2D‐ROESY, and chemical shift analysis coupled to DMSO titration has indicated the symmetrical nature and antiparallel orientation of Cys/Sec residues about the disulfide/diselenide bridges. Structural calculations of cystine and selenocystine derivatives using DFT further support the antiparallel orientation of Cys/Sec residues about disulfide/diselenide. The far‐ultraviolet (UV) region CD spectra of cystine and selenocystine derivatives have exhibited the negative Cotton effect (CE) for disulfide and positive for diselenide confirming the difference in the conformational preference of disulfide and diselenide. In the previously reported polymorphic structure of (Boc‐Sec‐OMe)2, the diselenide has right‐handed orientation. In the X‐ray structures of disulfide and diselenide analogues of Escherichia coli protein encoded by curli specific gene C (CgsC) retrieved from Protein Databank (PDB), disulfide has left‐handed and the diselenide right‐handed orientation. The current report provides the evidence for the local conformational difference between a disulfide and a diselenide group under unconstrained conditions, which may be useful for the rational replacement of disulfide by diselenide in polypeptide chains.
Fabrication, Microstructure, and Spectroscopic Properties of Transparent Yb0.118Lu0.464Y1.418O3 Ceramics
Authors: Maksimov Roman N. , Yurovskikh Artem S. , Shitov Vladislav A.
Published: February 2020

Highly transparent polycrystalline Yb0.118Lu0.464Y1.418O3 solid solution is fabricated at 1780 °C by solid‐state vacuum sintering of mixed sesquioxide nanoparticles synthesized in a laser plume. A comparative study of the structural and spectroscopic properties of pure sesquioxides and mixed composition is carried out. The lattice constant and grain size of the mixed composition are found to be intermediate between those of Yb:Y2O3 and Yb:Lu2O3, indicating the formation of a substitutional solid solution. Partial substitution of Y3+ for Lu3+ cations with a smaller ionic radius has weak adverse effect on the content of pores and the optical transmittance of ceramics, but causes compressive lattice strain, resulting in a blue shift of absorption bands. The width of the emission band centered at 1077 nm for the disordered structure is estimated to be 21 nm (full width at half maximum), which is 3–4 nm broader than that of single compositions.
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

A 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

“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.”
Sharp thresholds for nonlinear Hamiltonian cycles in hypergraphs
Authors: Narayanan Bhargav , Schacht Mathias
Published: February 2020

For positive integers r>ℓ, an r‐uniform hypergraph is called an ℓ‐cycle if there exists a cyclic ordering of its vertices such that each of its edges consists of r consecutive vertices, and such that every pair of consecutive edges (in the natural ordering of the edges) intersect in precisely ℓ vertices; such cycles are said to be linear when ℓ=1, and nonlinear when ℓ>1. We determine the sharp threshold for nonlinear Hamiltonian cycles and show that for all r>ℓ>1, the threshold for the appearance of a Hamiltonian ℓ‐cycle in the random r‐uniform hypergraph on n vertices is sharp and given by for an explicitly specified function λ. This resolves several questions raised by Dudek and Frieze in 2011.10
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

Giant 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

An 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

The 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

In 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

Mg‐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

In 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

Density‐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

The 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

The 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

Stable 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

Four 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

The 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

Hydroxyapatite (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

From 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

Endoplasmic 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

The 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

Exemestane, 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

As 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.
Kinetics and isotherm studies for adsorption of arsenic on ferric hydroxide by potentiostatic electrocoagulation
Authors: Binh Phan Thi , Van Anh Nguyen Thi , Thuy Mai Thi Thanh , Xuan Mai Thi
Published: February 2020

The potentiostatic electrocoagulation (PEC) using iron (CT3 steel) for anode material was applied to removal of arsenic from well water. Some parameters such as potential, electrolysis time, and initial arsenic concentrations were varied for research in this article. The arsenic concentrations before and after PEC processing were analysed by AAS method. The mass of ferric hydroxide was calculated via Faraday's law. The results showed that the residual arsenic concentration in water samples from initial arsenic concentration until 800 ppb is smaller than that of WHO requirement (10 ppb). The adsorption of arsenic on ferric hydroxide fitted well into pseudo second‐order kinetic equation, where its equilibrium adsorption capacity was linearly depended on the initial adsorption rate with R2 of 0.9864. The Langmuir parameters Nmax and KL were 23.58 mg/g and 1060 L/mg with correlation constant (R2) of 0.827, respectively.
Pregnane glycosides from Gymnema sylvestre
Authors: Yen Duong Thi Hai , Thu Vu Kim , Tai Bui Huu , Yen Pham Hai , Nhiem Nguyen Xuan , Kiem Phan Van
Published: February 2020

Three pregnane glycosides, gymnepregoside F (1), 12‐O‐(E)‐cinnamoylgymnepregoside F (2), and stephanoside I (3) were isolated from the leaves of Gymnema sylvestre (Retz.) R.Br. ex Schult. Their structures were identified on the basis of spectroscopic evidences and in comparison with those reported in the literature. All these compounds were reported from this genus Gymnema for the first time.
Rapid and efficient treatment of wastewater from fish sauce‐manufacturing factories by using the electrochemical oxidation process
Authors: Minh Bui Quang , Long Nguyen Nghia , Van Hien Pham , Dung Nguyen Tuan
Published: February 2020

Wastewater from fish sauce‐manufacturing Phung Hung Ltd. Company with high salinity has been treated applying the electrochemical oxidation process, using a Ti/CeO2‐Pt anode and different cathodes: copper, stainless steel and copper‐zinc alloy. The pH value and the applied current density have been also examinated. All three cathodes can be used for the organic pollutant electro‐oxidation, however Cu/Zn cathode exhibits a higher efficiency on by‐product nitrate removal. The investigation on the pH and current density showed that the electro‐oxidation process was favorably occurred at pH8 and 30 mA/cm2. After 60 min of electrolysis, ammonia, total nitrogen and COD can be discharged into the A column level of QCVN/11‐2015/BTNMT.