bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal torque distribution of distributed driving AGV under the condition of centroid change
Authors: Liu Wei , Liu Ping , Yu Yue , Zhang Qingjie , Wan Yidong , Wang Miufang
Published: November 2021

The torque distribution is researched under the condition of the centroid position of distributed drive automatic guided vehicle (AGV) with load platform and is uncertain due to the unknown movable load. The whole vehicle model under centroid variation, the efficiency model of the hub motor and the torque distribution control strategy based on a PID neural network are established. A hierarchical controller is designed to accurately ensure the economy and stability of the vehicle. Simulations of the proposed control strategy are conducted, the results show that the total power and lateral deviation distance of the driving wheels are reduced by 17.63% and 61.54% under low load conditions and 15.54% and 61.39% under high load conditions, respectively, compared with those of the driving wheels under the average torque distribution, and the goal of close slip rates of the driving wheels is achieved. A system prototype is developed and tested, and the experimental results agree with the simulation within error permissibility. The margin of error is less than 5.8%, the results demonstrate that the proposed control strategy is effective. This research can provide a theoretical and experimental basis for the torque optimization distribution of distributed drive AGVs under centroid variation conditions.
Metabolic profiling of attached and detached metformin and 2-deoxy-D-glucose treated breast cancer cells reveals adaptive changes in metabolome of detached cells
Authors: Repas Jernej , Zügner Elmar , Gole Boris , Bizjak Maruša , Potočnik Uroš , Magnes Christoph , Pavlin Mojca
Published: November 2021

Anchorage-independent growth of cancer cells in vitro is correlated to metastasis formation in vivo. Metformin use is associated with decreased breast cancer incidence and currently evaluated in cancer clinical trials. The combined treatment with metformin and 2-deoxy-D-glucose (2DG) in vitro induces detachment of viable MDA-MB-231 breast cancer cells that retain their proliferation capacity. This might be important for cell detachment from primary tumors, but the metabolic changes involved are unknown. We performed LC/MS metabolic profiling on separated attached and detached MDA-MB-231 cells treated with metformin and/or 2DG. High 2DG and metformin plus 2DG altered the metabolic profile similarly to metformin, inferring that metabolic changes are necessary but not sufficient while the specific effects of 2DG are crucial for detachment. Detached cells had higher NADPH levels and lower fatty acids and glutamine levels compared to attached cells, supporting the role of AMPK activation and reductive carboxylation in supporting anchorage-independent survival. Surprisingly, the metabolic profile of detached cells was closer to untreated control cells than attached treated cells, suggesting detachment might help cells adapt to energy stress. Metformin treated cells had higher fatty and amino acid levels with lower purine nucleotide levels, which is relevant for understanding the anticancer mechanisms of metformin.
Silanization of nanographene platelets improves interaction with the dentin bonding resin matrix and enhances interfacial bond integrity to dentin
Authors: Akram Zohaib , Aati Sultan , Shrestha Barsha , Clode Peta , Saunders Martin , Ngo Hien , Fawzy Amr
Published: November 2021

Synthesis and characterization of GNP and MPS-GNP to study their interaction within the resin matrix of dentin bonding agent, biological, and mechanical properties of the bonded specimens.
Correction: Microneedle-mediated delivery of MIL-100(Fe) as a tumor microenvironment-responsive biodegradable nanoplatform for O2-evolving chemophototherapy
Authors: Luo Sulan , Zhao Yiting , Pan Kewei , Zhou Yixian , Quan Guilan , Wen Xinguo , Pan Xin , Wu Chuanbin
Published: November 2021

Correction for ‘Microneedle-mediated delivery of MIL-100(Fe) as a tumor microenvironment-responsive biodegradable nanoplatform for O2-evolving chemophototherapy’ by Sulan Luo et al., Biomater. Sci., 2021, DOI: 10.1039/d1bm00888a.
Correction: Thiadiazole containing N- and S-rich highly ordered periodic mesoporous organosilica for efficient removal of Hg(II) from polluted water
Authors: Das Surajit , Chatterjee Sauvik , Mondal Saptarsi , Modak Arindam , Chandra Bijan Krishna , Das Suparna , Nessim Gilbert Daniel , Majee Adinath , Bhaumik Asim
Published: November 2021

Correction for ‘Thiadiazole containing N- and S-rich highly ordered periodic mesoporous organosilica for efficient removal of Hg(II) from polluted water’ by Asim Baumik et al., Chem. Commun., 2020, 56, 3963–3966, DOI 10.1039/D0CC00407C.
Supplementation of kefir ameliorates azoxymethane/dextran sulfate sodium induced colorectal cancer by modulating the gut microbiota
Authors: Zeng Xuejun , Jia Hang , Zhang Xiao , Wang Xin , Wang Zhouli , Gao Zhenpeng , Yuan Yahong , Yue Tianli
Published: November 2021

Supplementation of kefir alleviated AOM/DSS induced colorectal cancer by modulating the gut bacterial and fungal microbiota.
Tricholoma matsutake-derived peptide WFNNAGP protects against DSS-induced colitis by ameliorating oxidative stress and intestinal barrier dysfunction
Authors: Li Mengqi , Lv Renzhi , Wang Chuanzhi , Ge Qi , Du Hanting , Lin Songyi
Published: November 2021

WFNNAGP may reduce colonic inflammation in mice by enhancing oxidative defense systems and barrier function and may be a promising candidate for IBD intervention.
Quasi-two-dimensional NaCl crystals encapsulated between graphene sheets and their decomposition under an electron beam
Authors: Lehnert Tibor , Kretschmer Silvan , Bräuer Fredrik , Krasheninnikov Arkady V. , Kaiser Ute
Published: November 2021

Graphene encapsulation was used for systematic in situ investigations of the decomposition processes of encapsulated quasi-2-dimensional sodium chloride (NaCl) crystals in a transmission electron microscope (TEM).
Efficient single-photon pair generation by spontaneous parametric down-conversion in nonlinear plasmonic metasurfaces
Authors: Jin Boyuan , Mishra Dhananjay , Argyropoulos Christos
Published: November 2021

The presented work demonstrates a new efficient ultrathin entangled single-photon pair nanophotonic source based on spontaneous parametric down-conversion working at room temperature.
Topology modulation of 2D covalent organic frameworks via a “two-in-one” strategy
Authors: Zhao Ziqiang , Zhao Jinwei , Zhang Simeng , Zhang Guang , Chen Weiben , Yang Zongfan , Zhang Ting , Chen Long
Published: November 2021

By employing the “two-in-one” molecular design strategy, two new 2D COFs featuring a Kagome (kgm) lattice or a rhombic square (sql) structure can be selectively formed by varying the solvents and/or by adjusting the monomer concentrations.
Copper-catalyzed cascade radical cyclization of alkynoates: construction of aryldifluoromethylated coumarins
Authors: Zeng Piaopiao , Huang Xiaoxiao , Tang Wei , Chen Zhiwei
Published: November 2021

Synthesis of a variety of aryldifluoromethylated coumarins by cascade radical cyclization reactions in systems where alkynoates and α,α-difluoroarylacetic acids coexist, using (NH4)2S2O8 as oxidant and CuI as catalyst. The transformation was accomplished under mild conditions.
On the limitations of cationic polymerization of vinyl monomers in aqueous dispersed media
Authors: Destephen Aurélie , Ballard Nicholas
Published: November 2021

We investigate the effects of chain transfer to monomer and chain transfer to water on the molecular weight of polymers obtained by cationic polymerization in aqueous dispersed media.
Molecular weight and dispersity affect chain conformation and pH-response in weak polyelectrolyte brushes
Authors: Li Tzu-Han , Robertson Megan L. , Conrad Jacinta C.
Published: November 2021

The pH-dependence of the conformation of annealed polyelectrolyte brushes can be tuned by varying the molecular weight distribution, as characterizedviaweight-average molecular weight and dispersity.
Dependence of the liquid crystalline properties on the exactly controlled single-site functionalized density of mesogens focused on the alternating copolymer model
Authors: Zhang Ruixue , Li Xuwen , Ma Hongwei , Han Li , Li Chao , Zhang Songbo , Bai Hongyuan , Li Yang
Published: November 2021

Fluorinated liquid crystal polymers (FLCPs) with an alternating sequence of mesogenic moieties within their backbones were precisely constructed.
Polypyrrole nanoparticles embedded nitrogen-doped graphene composites as novel cathode for long life cycles and high-power zinc-ion hybrid supercapacitors
Authors: Pattananuwat Prasit , Pornprasertsuk Rojana , Qin Jiaqian , Prasertkaew Suchittra
Published: November 2021

The well-designed network structure of synthetic polypyrrole (PPy) nanoparticles embedded on a nitrogen-doped graphene (N-rGO) surface was utilized as a cathode for aqueous zinc-ion hybrid supercapacitors.
Theoretical insights into the effect of halogenated substituent on the electronic structure and spectroscopic properties of the favipiravir tautomeric forms and its implications for the treatment of COVID-19
Authors: Assis Letícia Cristina , de Castro Alexandre Alves , de Jesus João Paulo Almirão , da Cunha Elaine Fontes Ferreira , Nepovimova Eugenie , Krejcar Ondrej , Kuca Kamil , Ramalho Teodorico Castro , La Porta Felipe de Almeida
Published: November 2021

In this study, we systematically investigated the electronic structure, spectroscopic properties, and tautomerism of halogenated favipiravir compounds (fluorine, chlorine, and bromine) from a computational perspective.
Rapid preparation of PAM/N-CNT nanocomposite hydrogels by DEM frontal polymerization and its performance study
Authors: Li Bin , Liu Jizhen , Fu Dandan , Li Yongjing , Xu Xiaojia , Cheng Ming
Published: November 2021

In this study, a simple and eco-friendly method was proposed to efficiently prepare nanocomposite hydrogels with excellent mechanical properties and satisfactory pH response behaviour by frontal polymerization of DEM in close to 4 minutes.
Fabrication of biocompatible magneto-fluorescence nanoparticles as a platform for fluorescent sensor and magnetic hyperthermia applications
Authors: Sichamnan Arphaphon , Yong Nararat , Sillapaprayoon Siwapech , Pimtong Wittaya , Tang I.-Ming , Maneeprakorn Weerakanya , Pon-On Weeraphat
Published: November 2021

Multifunctional nanoparticles with special magnetic and optical properties have been attracting a great deal of attention due to their important applications in the bioanalytical and biomedical fields.
Halogenation of a twisted non-polar π-system as a tool to modulate phosphorescence at room temperature
Authors: Farias Giliandro , Salla Cristian A. M. , Aydemir Murat , Sturm Ludmilla , Dechambenoit Pierre , Durola Fabien , de Souza Bernardo , Bock Harald , Monkman Andrew P. , Bechtold Ivan H.
Published: November 2021

Twisted π-systems investigation showed a very unusual HAE, influencing independently the ISC and the dual phosphorescence emission, one being very persistent at room temperature and visible by eye in powder.
Biomechanics as driver of aggregation of tethers in adherent membranes
Authors: Li Long , Kamal Mohammad Arif , Stumpf Bernd Henning , Thibaudau Franck , Sengupta Kheya , Smith Ana-Sunčana
Published: November 2021

Experiments and simulations show that large length difference does not necessarily lead to segregation of tethers within adhesion domains.
Shape-programmable magneto-active elastomer composites for curve and biomimetic behavior imitation
Authors: Gong Di , Yang Fan , Lin Dezhao , Qian Wenbo , Li Ruihong , Li Chenghong , Chen Hongwei , Jia Sheng
Published: November 2021

A programming methodology for the fabrication of soft-magnetic-materials based on magneto-active elastomers for curve and biomimetic behaviors imitation.
Injectable and self-healing nanocomposite hydrogel loading needle-like nano-hydroxyapatite and graphene oxide for synergistic tumour proliferation inhibition and photothermal therapy
Authors: Qi Yujie , Qian Zhiyi , Yuan Weizhong , Li Zhihong
Published: November 2021

An injectable and self-healing nanocomposite hydrogel containing HAP and GO can achieve synergistic tumour proliferation inhibition and photothermal therapy.
Controlling emitting dipole orientations by N^O-ancillary electronic effects of [Ir(C^N)2(N^O)]-heteroleptic Ir(iii)-complexes towards efficient near-infrared (NIR) polymer light-emitting diodes (PLEDs)
Authors: Hou Siyu , Liu Jiaxiang , Wang Baowen , Miao Tiezheng , Lü Xingqiang , Li Wentao , Fu Guorui , Feng Weixu , Wong Wai-Yeung
Published: November 2021

For [Ir(C^N)2(N^O)] complexes 1–3, the N^O-(Ln)-induced TDM and orientation were responsible for their efficient NIR-PLEDs.
Structure–property relationship study of blue thermally activated delayed fluorescence molecules with different donor and position substitutions: theoretical perspective and molecular design
Authors: Song Yuzhi , Li Bihe , Liu Songsong , Qin Ming , Gao Yang , Zhang Kai , Lin Lili , Wang Chuan-Kui , Fan Jianzhong
Published: November 2021

Blue-efficient thermally-activated delayed fluorescence emitters are widely desired in organic light-emitting diodes due to their advantages in both improving display resolution and providing better pixels.
No swan song for Sun-as-a-star helioseismology: Performances of the Solar-SONG prototype for individual mode characterisation
Authors: Breton S. N. , Pallé P. L. , García R. A. , Fredslund Andersen M. , Grundahl F. , Christensen-Dalsgaard J. , Kjeldsen H. , Mathur S.
Published: November 2021

The GOLF instrument on board SoHO has been in operation for almost 25 years, but the ageing of the instrument has now strongly affected its performance, especially in the low-frequency pressure-mode (p-mode) region. At the end of the SoHO mission, the ground-based network BiSON will remain the only facility able to perform Sun-integrated helioseismic observations. Therefore, we want to assess the helioseismic performances of an échelle spectrograph such as SONG. The high precision of such an instrument and the quality of the data acquired for asteroseismic purposes call for an evaluation of the instrument’s ability to perform global radial-velocity measurements of the solar disk. Data acquired during the Solar-SONG 2018 observation campaign at the Teide Observatory are used to study mid- and low-frequencypmodes. A Solar-SONG time series of 30 days in duration is reduced with a combination of the traditional IDLiSONGpipeline and a newPythonpipeline described in this paper. A mode fitting method built around a Bayesian approach is then performed on the Solar-SONG and contemporaneous GOLF, BiSON, and HMI data. For this contemporaneous time series, Solar-SONG is able to characterise p modes at a lower frequency than BiSON or GOLF (1750 μHz versus 1946 and 2157 μHz, respectively), while for HMI it is possible to characterise a mode at 1686 μHz. The decrease in GOLF sensitivity is then evaluated through the evolution of its low-frequencyp-mode characterisation abilities over the years: a set of 30-day-long GOLF time series, considered at the same period of the year from 1996 to 2017, is analysed. We show that it is more difficult to accurately characterise p modes in the range 1680 to 2160 μHz when considering the most recent time series. By comparing the global power level of different frequency regions, we also observe that the Solar-SONG noise level in the 1000 to 1500 μHz region is lower than for any GOLF subseries considered in this work. While the globalp-mode power-level ratio is larger for GOLF during the first years of the mission, this ratio decreases over the years and is bested by Solar-SONG for every time series after 2000. All these observations strongly suggest that efforts should be made towards deploying more Solar-SONG nodes in order to acquire longer time series with better duty cycles.
Numerical analysis of indirect noise generated by compositional inhomogeneities using large eddy simulation
Authors: Gong Y. , Jones W. P. , Marquis A. J.
Published: November 2021

In the present work, indirect noises generated by compositional disturbances in a non-isotropic convergent nozzle are studied using Large Eddy Simulations (LESs). An in-house compressible LES code, Boundary Fitted Flow Integrator-LESc, is utilized to simulate the noise generation in the system. A non-reflective outlet boundary condition is used to eliminate numerical reflections and to ensure the reproduction of the operating conditions in the experiments. The experiments are designed to feature two configurations with different injection positions, which enable the separation of direct and indirect noises. Different operating conditions are investigated, including different injection gases and air mass flow rates. This present paper compares computational results with the experimental measurements. The results revealed that the processes of direct and indirect noise generation are successfully reproduced in the LES, with the noise magnitudes in good agreement with those in the measurements. Injection of gases with smaller (He) and larger (CO2) molar masses compared to air is found to generate negative and positive indirect noises, respectively, in the LES, which is consistent with the experimental findings. The effect of different air mass flow rates is also investigated and discussed, and the direct noise and indirect noise amplitudes are both found to be closely related to the air mass flow rate.
CO2 activation at atomically dispersed Si sites of N-doped graphenes: Insight into distinct electron mechanisms from first-principles calculations
Authors: Fang Lei , Cao Zexing
Published: November 2021

Two types of single-atom Si-embedded N-doped graphene sheets, denoted as SiNxC3−x and SiNxC4−x, were designed for CO2 activation and electroreduction. The first-principles calculations show that CO2 can be chemically adsorbed at the single-atom Si sites of SiN1C2, SiN2C1, SiN3C0, SiN3C1, and SiN4C0 monolayers with quite low-energy barriers and exothermicity to some extent. Unexpectedly, CO2 activation and capture at the atomically dispersed Si sites of SiNxC3−x and SiNxC4−x follow different electron mechanisms where the three-coordinated Si in SiNxC3−x behaves as an electron donor while the four-coordinated Si acts as an electron shuttle for the electron transfer from the SiNxC4−x framework to CO2. For SiNxC4−x, the low-energy Si-pz center is a prerequisite for the Si site to capture the electron from the support framework, which is beneficial for the electron transfer to CO2. The activity of SiNxC3−x depends on both the Si-pz band center and the electron population at the three-coordinated Si, resulting in the conventional linear correlation between the activity and the p-band center not being observed. Furthermore, the SiN3C0 sheet is predicted to be quite a promising electrode material for CO2 electrochemical reduction to HCOOH, CH3OH, and CH4 with quite low limiting potentials.
Properties of RbHgF3 fluoro-perovskite under growing hydrostatic pressure from first-principles calculations
Authors: Rahman M. Atikur , Babu Md. Majibul Haque , Karimunnesa Syeda , Kholil Md. Ibrahim
Published: November 2021

Mercury fluoro-perovskites based on Rubidium have a lot of technical relevance nowadays, especially in optical and semiconductive applications. A Cambridge Serial Total Energy Package code analysis using the Density Functional Theory was performed to calculate the structural, electronic, elastic, optical, and thermodynamic characteristics as well as the bonding nature of cubic fluoro-perovskites RbHgF3 under various hydrostatic pressures. To determine the total energy, the Perdew–Berke–Ernzerhof generalized gradient approximation was used to manage the exchange–correlation potential. The effects of hydrostatic pressure are studied in the region of 0–20 GPa, which maintains the cubic stable condition of RbHgF3 fluoro-perovskite. Experimental and prior theoretical results agree well with the calculated lattice parameters. When the pressure reached 20 GPa from 0 GPa, the volume, bond length, and lattice constant decreased. The bandgaps demonstrate an indirect band structure, with substantial reductions at various external forces. The total density of states reveals a non-metallic behavior. Mechanical properties satisfy the stability criteria until 20 GPa for this compound, and ductile behavior is also found within that pressure range. External stress modifies the optical characteristics a bit such as the complicated dielectric function, absorption, conductivity, and reflectivity. The presence of blue shift is confirmed by the movement of absorption edges toward higher energies, making this material an intriguing option for optical devices.
A new undersea volcano is born east of Africa
Authors: Lopatka Alex
Published: November 2021

Geophysical and oceanographic observations establish how a deep magma chamber fueled an extraordinary eruption.
Plasmonic Si@Au core-satellite nanoparticles prepared by laser-assisted synthesis for photothermal therapy
Authors: Al-Kattan Ahmed , Tselikov Gleb , Popov Anton A. , Kabashin Andrei V.
Published: November 2021

We describe a laser-assisted methodology for the fabrication of Si@Au core-satellite nanostructures for photothermal therapy applications. The methodology consists in laser ablative synthesis of Si and Au NPs in water/ethanol solutions, followed by a chemical modification of the Si NPs by APTMS and their subsequent decoration by the Au NPs. We show that despite a relatively small size (< 40 nm) the formed core-satellites exhibit a strong plasmonic absorption peak centred around 610 nm and having a large tail over 700 nm overlapping with the first optical window of relative tissue transparency. Being relatively small and exempt of any toxic impurity due to ultraclean laser synthesis, the fabricated nanoparticles promise a major advancement of imaging and phototherapy modalities based on plasmonic properties of nanomatererials.
Laser-ablative synthesis of stable size-tunable Bi nanoparticles and their functionalization for radiotherapy applications
Authors: Tikhonowski G V , Popov A A , Popova-Kuznetsova E A , Klimentov S M , Prasad P N , Kabashin A V
Published: November 2021

Nanoformulations of high-Z elements can improve therapeutic outcome in radiotherapy-based treatment of tumors, but current nanomedicine implementations in radiotherapy still need biocompatible, non-toxic nano-agents exhibiting low polydispersity and high colloidal stability. Here, we elaborate methods of femtosecond (fs) laser ablation in water and organic solvents to fabricate stable aqueous colloidal solutions of ultrapure elemental Bi nanoparticles (NPs) and characterize them. We show that fs laser ablation of Bi target leads to the formation of spherical elemental Bi NPs having 25 nm mean size and wide size-dispersion. NPs prepared in water undergo fast conversion into 400-500 nm flake-like nanosheets, while NPs prepared in acetone demonstrate a high colloidal stability. We then employ methods of fs laser fragmentation to control mean size and size dispersion of Bi NPs. Stable aqueous solution of Bi NPs suitable for biomedical applications can be obtained by coating with Pluronic® F-127. We finally show that surface modification of Bi NPs increases its colloidal stability in phosphate buffer saline (PBS) solution by more than 6 fold. Exempt of any toxic synthetic by-products, laser-ablated Bi NPs present a novel appealing nanoplatform for image-guided combination photo- and radiotherapy.
Evolution of the properties of nanomaterials obtained by pulsed laser ablation
Authors: Faizullayeva S , Klimentov S M , Popov A A
Published: November 2021

The synthesis and application of metal and ceramic nanoparticle are significant subject in science and engineering. The metal nanoparticles such as gold, silver, and copper nanoparticles have more application in material science, nanomedicine, electronic, photonic, and art. One of the green methods for preparation of metal nanoparticles is laser ablation technique that offers a unique tool for nanofabrication of nanoparticles. In this work, gold colloids were prepared by pulsed laser ablation of high purity gold plate immersed in deionized water and 10μM NaCl solution. After ablation process, we study the change in the size distribution of nanoparticles after the ablation process for a month.
Proton magnetization relaxation in aqueous suspensions of composite silicon-iron nanoparticles for biomedical applications
Authors: Kargina Yu V , Mironova A D , Kharin A Yu , Perepukhov A M , Ischenko A A , Timoshenko V Yu
Published: November 2021

Silicon-iron composite nanoparticles produced by arc-discharge plasma ablation method were characterized by scanning electron microscopy, dynamic light scattering, X-ray fluorescence diffractometry, and the effect of iron content and size of the nanoparticles on hydrogen nuclei magnetization relaxation were investigated by nuclear magnetic resonance relaxometry. It was shown that increasing in iron content during the synthesis leads to distortion of the spherical shape of the nanoparticles and increasing of their mean sizes from 140 nm to 350 nm. Nonlinear dependence of the longitudinal and transverse relaxivities from iron content was demonstrated. Increase in the iron concentration above 2.5 at. % leads to reduction of the both relaxivities, which can be explained by nonuniform distribution of iron and formation of iron containing agglomerates. It was shown that transverse and longitudinal relaxivities of the nanoparticles in their aqueous solutions inversely proportional from their hydrodynamic diameters in the range of 100 – 300 nm. The possibilities of using composite silicon-iron nanoparticles for biomedical applications are discussed.
Prospects for the use of hexagonal ferrite particles for targeted drug delivery and local heating of organic nanocontainers
Authors: Alykova A F , Rybakov A V , Stepkina A P , Smirnov V V , Alykova O M , Zavestovskaya I N
Published: November 2021

Currently, it seems more promising to combine controlled drug delivery using liposomes or other agents in combination with ferrite nanoparticles for the treatment of oncological diseases. The release of drugs can be carried out by heating the particles with an alternating magnetic field. In this case, the local temperature can be set more precisely by selecting the chemical composition and structure of the ferrite in such a way as to obtain the necessary Curie temperature. Moreover, it is possible to concentrate nanoparticles in the desired area with extremely small dimensions using an oriented constant magnetic field. The article analyzes the existing methods of delivering antitumor antibiotics using magnetic nanoparticles, presents its own solutions in the field of magnetic transportation and tracking of nanocontainers, considers the problems of the depth of penetration of the magnetic field into the tissues of the body and minimizing their hyperthermia. The authors proposed to use magnetic particles of hexagonal strontium ferrite synthesized by cryochemical technology for controlled delivery and release by heating.
Comparative analysis of SERS-active colloidal silver solutions of various type and prospects of their applications
Authors: Altunina A V , Zalygin A V , Oleinikov V A
Published: November 2021

Raman spectroscopy is a promising method for optical vibrational spectroscopy. Nowadays, Raman spectroscopy finds many applications, in particular, in biological and medical diagnostics. However, the Raman scattering can be enhanced using the Surface-enhanced Raman scattering method. Colloidal solutions of noble metals are used as SERS-active systems. In this work, the enhancing factors were estimated for colloidal silver solutions of three different types (citrate, borohydride, chloride) with two substances (phenylalanine, cytochrome C). Phenylalanine is a widely used model substance for Raman and Surface-enhanced Raman spectroscopy. Cytochrome C is one of the most researched proteins. It involves in the electron transport chain of the mitochondrial inner membrane and provides cellular respiration. Borohydride, citrate and chloride sols with phenylalanine gave an enhancement about 50, 200 and 30 times, respectively, and with cytochrome C about 30, 160 and 20, respectively. A comparative analysis of active and inactive sols by SERS and absorption spectroscopy was also performed. The absorption spectra of active sols have characteristic maxima in the region of 400 nm. Both the SERS method of model substances and absorption spectroscopy can be used to assess the enhancing properties.
Temperature monitoring through nanoparticle-activated proton relaxation for magnetic resonance imaging application
Authors: Mironova A D , Kargina Yu V , Perepukhov A M , Pavlova O S , Gulyaev M V , Pirogov Yu A , Timoshenko V Yu
Published: November 2021

An effect of temperature on the proton relaxation times in aqueous suspensions of solid-state nanoparticles (NPs) is comparatively investigated for the NPs’ composition varied from pure silicon (Si) with natural isotope content to Si with iron impurities as well as for Si NPs enriched with Si-29 isotope. For all types of the investigated NPs both the longitudinal and transverse relaxation times become shorter compared with that for pure water because of the interaction of electron spin centers in those NPs with nuclear spins of the protons in water molecules. The obtained results allow us to evaluate the temperature sensitivity of NP-based systems for their biomedical applications in magnetic resonance imaging (MRI).
Biological behavior of a new 68Ga-labelled glucose derivative as a potential agent for tumor imaging
Authors: Tishchenko V K , Petriev V M , Kuzenkova K A , Zavestovskaya I N , Shegai P V , Ivanov S A , Kaprin A D
Published: November 2021

Glucose analogs and derivatives labeled with positron emitter 68Ga are considered to be a promising alternative to widely used radiotracer 18F-FDG for tumor PET imaging. In this study a biodistribution of a new glucose derivative labeled with 68Ga (68Ga-NODA-thioglucose) was investigated. All biodistribution studies were carried out in Balb/c mice with experimental model of tumor or aseptic inflammation. The tumor uptake of 68Ga-NODA-TG decreased throughout the study from 3.00±0.08 % ID/g to 1.06±0.04 %ID/g. The peak amount of 68Ga-NODA-TG in muscle with inflammation reached 4.33±0.12 % ID/g, decreasing to 0.23±0.08 % ID/g. In other organs and tissues the biodistribution of 68Ga-NODA-TG was similar in tumor-bearing mice and mice with aseptic inflammation. In conclusion, the obtained results suggest that 68Ga-NODA-TG has the potential for clinical application as a PET tracer.
Effect of concentration areas in sensitive analysis of a hybrid solar Brayton cycle
Authors: Moreno-Gamboa F , Florez-Solano E , Espinel-Blanco E
Published: November 2021

A simple hybrid solar thermal Brayton cycle plant thermodynamic model is evaluated in northern Colombia, where the maximum solar radiation values in the country are found. The model considers the different irreversibilities of the cycle and is coupled to a model for estimating direct solar radiation as a complementary energy source for the plant. The stability in the operation of the cycle is determined by a combustion chamber that complements the energy supply. As a result of the analysis, this work presents the sensitivity analysis of different operating parameters of the plant as a function of the areas of the concentration ratio of the solar system when the contribution of this system is maximum. It is observed that fuel consumption is reduced by 34.7% when increasing the concentration ratio between 200 and 700.
Physical parameters for the estimation of the return coefficient in the sewer of the La Chivera watershed
Authors: Cely-Calixto N J , Bonilla-Granados C A , Gallardo-Amaya R J
Published: November 2021

Estimating the amount of flow carried by the sanitary sewer system in a locality is essential for the design of new facilities. Having a record of the flow rates allows the adequate hydraulic design of a drainage system. The objective of this work is to determine the physical parameters for the estimation of the return coefficient that allows estimating the flow rates for the sanitary sewer of the La Chivera watershed, San José de Cúcuta, Colombia. In this sense, dry weather monitoring of the wastewater in the study area was carried out. The data collected in the field were used to construct the hourly flow variation curve or inflow hydrograph in the drainage system. The average hourly flow parameters were estimated with a value of 205.7 m3/h, a value recorded at the 11th hour of the day. Similarly, the average daily flow was determined with a value of 180.3 m3/h, while the maximum peak factor was 1.14. Finally, through the physical parameters of the sanitary sewer, the return coefficient was determined, which is 0.72, a value that represents the conditions of the study area.
The 3rd Southeast Asian Conference on Geophysics (SEACG) 2020: Future Challenges and Opportunities in Geophysics (Preface)
Authors: Zulfakriza  , Hendriyana Andri , Saygin Erdinc , Chhun Chanmaly
Published: November 2021

The issue of IOP Conference Series: Earth and Environmental Science contains the outstanding papers presented at Southeast Asian Conference on Geophysics (SEACG) 2020. Due to Covid-19 Pandemic, the 3rd SEACG 2020 Conference was held online on 3 – 5 November 2020.

List of Committees SEACG 2020, Documetation, Images are available in this pdf.
Earthquake Swarm Analysis around Mt. Salak, West Java, Indonesia, Using BMKG Data from August 10 to November 24, 2019
Authors: Supendi Pepen , Puspito Nanang T. , Nugraha Andri Dian , Widiyantoro Sri , Abdullah Chalid Idham , Daryono  , Karnawati Dwikorita , Rohadi Supriyanto , Zulfakriza  , Sahara David P.
Published: November 2021

Earthquake swarms commonly come approximately active tectonic and volcanic area. Interestingly, the swarm events occurred ~23 km southwest from Mt. Salak-Bogor, West Java, Indonesia, from August 10 to November 24, 2019, and were recorded by local/regional network of the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). Our previous study showed that in this area a destructive ML4.6 earthquake with thrust faulting occurred on September 8, 2012. The double-difference method was applied to update the hypocenter locations from the BMKG data. In the time period of ~3.5 months, we relocated 79 swarm events with ~9.4 km depth average for local magnitude (ML) 2.2 to 4.2. The source mechanism result for selected events shows a strike-slip faulting. Our interpretation is that these swarm events are probably related to stress change due to volcano-tectonic activity.
The Estimation of Seismic Site Amplification of Bukittinggi City, West Sumatera, Indonesia
Authors: Marjiyono  , Setiadi I , Setiawan J
Published: November 2021

Bukittinggi city area is exposed substantial risk of both, close to seismic source line and site amplification due to soft surface sediment / soil layer. The Great Sumateran Fault (GSF) which is crossing this area, notorious as a very active seismic source. Its responsible to some major earthquake in the vicinity of the fault line. Generally, Bukittinggi area is covered by volcanic product as pumiceous tuff. We applied combined array and single station microtremor measurement to characterize near surface sediment in this area. Based on analysis microtremor single station and array using spatial autocorrelation (SPAC) method, weathered surface layer thickness is in the range of 0-108 m with shear wave velocity in the range of 62-190 m/s, while the fresh pumiceous tuff is in the range of 375-629 m/s. The estimation of site amplification in this area which is indicated by mean amplification is in the range of 1-1.95. The high amplification zone is occupies the northernmost area and some area locally in the southern part of Bukittinggi city.
The Spatio-temporal Analysis of b-value in the Banda Arc, Indonesia
Authors: Al-Rasyid Muhammad Bani , Rusman Mira Nailufar , Hamonangan Daniel , Supendi Pepen , Kirana Kartika Hajar
Published: November 2021

Banda arc is a complex tectonic structure manifests by high seismicity due to the collision of a continent and an intra-oceanic island arc. Using the relocated earthquakes data from ISC-EHB and BMKG catalogues from the time period of 1960 to 2018, we have conducted a spatial and temporal variation of b-value using the Guttenberg-Richter formula in the area. Our results show that the spatial distribution of low b-values located in the south of Ambon Island and southeast of Buru Island. On the other hand, the temporal variation of b-value shows a decrease in the northern part of the Banda sea probably high potential to produce large earthquakes in the future. Therefore, further mitigation is needed to minimize the impact of earthquakes in the area.
Frequency Dependent Magnetic Susceptibility in Topsoil of Bandung City, Indonesia
Authors: Kirana K H , Apriliawardani J , Ariza D , Fitriani D , Agustine E , Bijaksana S , Fajar S J , Nugraha M G
Published: November 2021

Soil contains lithogenic components as well as anthropogenic components including combustion residues from traffic activities. The high traffic activities in major cities such as Bandung have caused the air pollution level to increase significantly. These activities might also produce significant combustion residues that accumulate, among others, in the topsoils. Compared with lithogenic components in topsoil, the anthropogenic combustion residues might have different magnetic signatures that could be detected by magnetic measurements. In this study, 38 topsoil samples from 19 roadside sampling points in Bandung City were collected and magnetically analysed to map the magnetic signatures due to traffic activities. The samples were measured for magnetic susceptibility using Bartington MS2B Susceptibility Meter and hysteresis parameter analysed from Vibrating Sample Magnetometer (VSM). The results show that the values of mass-specific magnetic susceptibility (χLF) vary from 391.20 to 1835.20×10-8 m3/kg with the average value of 1012.16 × 10-8 m3/kg while the values of frequency dependent susceptibility (χFD%) vary from 0.54% to 4.48% with the average value of 1.9%. The relatively high value of magnetic susceptibility indicates higher concentration of magnetic minerals compared to that of pristine topsoil around Bandung. This is in agreement with similar studies on roadside topsoil elsewhere. The poor correlation between mass-specific magnetic susceptibility and frequency dependent magnetic susceptibility infers that the magnetic minerals are predominantly non superparamagnetic. This finding is supported by magnetic hysteresis parameters showing that the predominant grains are likely to be pseudo-single domain (PSD) if magnetite is assumed to be the predominant magnetic mineral. Similar studies in German and China reported that the predominant magnetic mineral is mixture of single domain to multi domain magnetite.
Geomagnetic inverse modeling to estimate the volume of magnetization in areas with topographic variations
Authors: Wahyudi Eko J
Published: November 2021

A three-dimensional geomagnetic modeling is proposed to obtain information about a magnetization over topographic area from magnetic total force from land data survey. The model is divided into three-dimensional mesh grid of rectangular prisms that cover a finite depth below topographic elevation. The model parameter is assigned to each prism describing magnetization. A set of linear equations was formulated in terms of volume magnetization for each prism. The inverse calculation is obtained using the solution of over-determined problems. In this inverse calculation over three-dimensional mesh grid, the weighted matrix will be used to determine distribution of volume magnetization in the subsurface and keep the zero value of volume magnetization above the surface. A computer program has been tested with artificial topographic data and applied to digital elevation model of Bandung. The result of the inversion shows the comparison between synthetic model and inverse model to provide several analysis of algorithm performance. The high magnetization value can be characterize using inverse model up to 77% of volume area with average success recovery of model parameter value up to 56%.
Characteristic of the 2010-2020 Earthquakes in North Arm of Sulawesi based on Focal Mechanism and b-value
Authors: Astuti A P , Elsera E M , Massinai M F I , Akbar M A
Published: November 2021

The north arm of Sulawesi has a fairly high level of seismicity. The North Sulawesi arm is bounded in the south by the Palu-Koro Fault, the northern part is bounded by the North Sulawesi Trench and the Molluca Sea Thrust in the east. Therefore, this study aims to analyze the characteristic of the 2010-2020 earthquakes in the north arm of Sulawesi by analyzing the earthquake’s focal mechanism and mapping the b-value using the maximum likelihood method. From this study, we obtained the focal mechanism consist of thrust and strike-slip, this is due to the activity of faults and subduction zones in the North arm of Sulawesi such as the Palu-koro fault, the Gorontalo Fault, North Sulawesi Trench, Molucca Sea Collision, and several other faults that affect the seismicity of this region. The variation of the b-value ranging from 0.5-1.1 These studies indicate that thrust fault regions have lower b-values, while strike-slip fault regions have intermediate b-values. Meanwhile, areas with active volcanoes tend to have high b-values. The results of this research can be used as a basis for decision making related to earthquake mitigation in this area in the future.
Focal Mechanism Analysis of the September 25th, 2019 Mw 6.5 Ambon Earthquake and Its Implication for Seismotectonics
Authors: Daniarsyad Gatut , Vita Aprilia Nur , Wei Shengji
Published: November 2021

On September 25th, 2019, an Mw 6.5 earthquake occurred in Ambon, Maluku Province, Indonesia, and caused casualties and infrastructures damages. The epicenter located in a tectonically active region with the potential strike-slip and thrust faulting earthquake sources, yet the responsible fault is still not well understood. Based on focal mechanism solutions from available seismological agencies, i.e. USGS, GFZ, GCMT, and BMKG, the earthquake has a similar strike-slip focal mechanism, although there are discrepancies on detailed source parameters. To provide a better understanding of the earthquake mechanism and seismotectonic, we apply the Cut-and-Paste (CAP) focal mechanism inversion method to broadband seismic waveforms from regional and teleseismic distances. The CAP inversion results on the regional data grouped in different distance ranges show a robust strike-slip solution. We then refine the earthquake focal depth by performing the CAPtele inversion and resulted in a depth of 12 km with similar fault plane solution as the regionals. The ruptured fault plane is resolved by a directivity analysis using azimuthal pattern of the apparent source durations, which indicates an obvious unilateral rupture propagation toward SSE direction. Our result suggests the NNW-SSE orientated fault is the ruptured fault plane, which is also consistent with the near N-S distributed aftershocks. This fault is located in a narrow sea between Seram, Ambon and Haruku island and was not reported yet in previous studies. The Coulomb failure stress (CFS) changes analysis of the mainshock shows that the Ambon earthquake has promoted the off-fault aftershocks which occurred to the west of the ruptured fault.
Results of land subsidence measurement using GPS method in the Jakarta groundwater basin in 2015-2019
Authors: Abdullah F M , Andriyanto H , Nababan J R , Abdillah F , Sulistyawan R I H
Published: November 2021

The development of population and development activities in big cities in Indonesia, especially in the city of Jakarta and surrounding areas is very rapid. From several land subsidence studies, several factors have been identified that cause land subsidence, namely: excessive groundwater extraction, reduction due to building/infrastructure loads, subsidence due to natural consolidation of soft soil layers, and subsidence due to tectonic forces. At present the exploitation of ground water for industrial and residential needs is at a level that needs attention. Excessive pumping of groundwater will cause a decrease in the quantity of ground water, entry of seawater into the land (sea water intrusion) and land subsidence. Symptoms of the negative impact of land subsidence have been felt in several areas, especially in industrial areas located in the northern part of Jakarta. This land subsidence can be measured by GPS or satellite geodetic method, which have begun to develop in Indonesia in the past two decades. Measurements were made using the radial method at 53 GPS points in 2015 up to 100 measurement points in 2019 in Jakarta Groundwater Basin. The result of these campaign GPS surveys that is northern part of Jakarta relatively had higher subsidence rate than the southern. The largest subsidence almost reached 6.2 cm/year in Muara Baru in northern area which is southern area only suffered an average rate of 1.16 cm/year.
The determination of prospective reservoirs in the slope environment of the Tarakan Basin (Indonesia) by using sequence stratigraphy, rock physics and AI inversion
Authors: Aminulloh D , Tampubolon B T , Sukmono S
Published: November 2021

Prospective reservoirs in the Tarakan Basin are mostly deposited in the Middle Miocene to Pliocene and related to the change of depositional environment from transgressive to regressive sedimentary environment. Log sequence stratigraphic analysis in well AST 1 shows that transgressive and lowstand system tracts were deposited during the study area. Hashin-Shtrikman method is used in the rock physics analysis to identify the relative rock hardness and integrated with gamma ray log, NPHI, and resistivity data analysis. The result show that potential reservoir exist at the depth range of 7650-7725 feets and associates with low velocity, low gamma ray, low NPHI, high resistivity values. The potential reservoir interval was deposited under low stand system tract of slope depositional environment. The acoustic impedance (AI) map shows that the low AI’s are mostly located in the northwestern part of the study area.
Exploring Reservoir within Hugin Formation in Theta Vest Structure using 4-D Seismic and Machine Learning Approach
Authors: Hardanto Lilik T. , Abdurrachman Mirzam , Nugroho Dwiharso
Published: November 2021

This paper aims to identify the oil distribution using 4-D seismic below a complex 3-D surface in Hugin Formation using machine learning and geobody detection. The exploration well 15/9-19-SR, drilled to the Theta Vest structure, was based on the interpretation of reprocessed ST8215R 3-D seismic survey data from 1991 in the Sleipner area, encountered oil in the Jurassic Hugin Formation. The drills stem test showed outstanding production capacities through time, with low water cut and low GOR. 4-D seismic has all the traditional benefits of 3-D seismic. A significant additional potential benefit is that fluid-flow processes can be directly imaged. The 4-D seismic analysis was conducted in 2012 to repeat the 3-D seismic surveys and analyze images in time-lapse mode to monitor time-varying fluid-flow processes during reservoir production. A comprehensive study of the structure and the discovery has been performed and is reported. The DNN method to predict facies far away from existing production wells by using facies log well to supervise seismic inversion created by the Seismic Color Inversion method. It can detect some oil pockets distribution and risk the well planning and the right candidate for new proposed wells.