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Weber, Martin, Gábor Balázs, Alexander V. Virovets, Eugenia Peresypkina e Manfred Scheer. "Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex". Molecules 26, n. 13 (26 giugno 2021): 3920. http://dx.doi.org/10.3390/molecules26133920.
Abstract (sommario):
By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.
2
Zafar, Mohd Farhan, e M. Arif Siddiqui. "Mechanical Characterization of the Natural Fiber Reinforced Polystyrene Composite". Materials Science Forum 969 (agosto 2019): 152–56. http://dx.doi.org/10.4028/www.scientific.net/msf.969.152.
Abstract (sommario):
In the present work, polystyrene composites using wheat husk, rice husk and mustard husk as fillers are synthesized using in-situ polymerisation technique. Three different filler loading (5%, 10% and 15 %) and three different filler sizes (250-355 µ, 355-500 µ, 500-710 µ) were utilized for the studying the effect of these compositions on different mechanical properties of the synthesized composites. The results have shown that the filler size 250-355 µ and 5 % loading give the maximum values for tensile strength, flexural strength and hardness for all the three types of fillers. While in case of water absorptivity lower the size/loading, lesser would be the water absorbed. The SEM analysis is done to study the fractured surface of the specimen.
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Kusuma, Yayan Wahyu C., Siti R. Ariati, Rosniati A. Risna, Chika Mitsuyuki, Yoshihisa Suyama e Yuji Isagi. "Seedling Selection Using Molecular Approach for Ex Situ Conservation of Critically Endangered Tree Species (Vatica bantamensis (Hassk.) Benth. & Hook. ex Miq.) in Java, Indonesia". Tropical Conservation Science 12 (gennaio 2019): 194008291984950. http://dx.doi.org/10.1177/1940082919849506.
Abstract (sommario):
Ex situ conservation is an important complementary strategy for in situ to conserve endangered plant species. However, the limited areas designated for ex situ conservation such as in botanic gardens have become a great challenge for conservation practitioners and scientists attempting to optimally conserve the genetic diversity of targeted plant species. Our study aimed to assess genetic diversity and structure of wild seedlings of Vatica bantamensis, an endemic and critically endangered dipterocarp from Java (Indonesia). We also estimated genetic differentiation between the wild seedlings and existing ex situ collection and evaluated the genetic diversity preserved in the ex situ collection. Our analysis, using 730 single-nucleotide polymorphisms loci, showed that wild seedlings exhibited higher genetic diversity than the ex situ collection (nucleotide diversity, µ = 0.26 and 0.16, respectively). Significant genetic differentiation was also detected ( FST = 0.32) between wild seedlings and ex situ collection. Furthermore, we found high kinship within the ex situ collection suggesting low genetic diversity since the founding collection. We also detected three distinct genetic clusters from all samples combined (analysis of molecular variance, ϕ = 0.48, p < .001), with two clusters present in the wild seedlings that were not represented in the ex situ collection. We recommend that supplementary collections from the two newly identified genetic clusters in the wild seedlings should be incorporated to increase genetic diversity in the ex situ collection. Furthermore, our study demonstrated that understanding the population genetics of targeted endangered species provides better results for ex situ conservation strategies.
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Iwasaki, Nozomu, Hiroshi Hasegawa, Yusuke Tamenori, Mutsuro Kikunaga, Toshihiro Yoshimura e Hikaru Sawai. "Synchrotron µ-XRF mapping analysis of trace elements in in-situ cultured Japanese red coral, Corallium japonicum". PeerJ 10 (23 agosto 2022): e13931. http://dx.doi.org/10.7717/peerj.13931.
Abstract (sommario):
Precious corals belong to the family Coralliidae (Cnidaria, Octocorallia), and their axis, which consists of high magnesian calcium carbonate, has long been used in jewelry. With its low growth rate and long lifespan, precious coral is a representative taxon of the vulnerable marine ecosystem. Due to years of overfishing, coral fishery has become a controversial issue. To estimate the growth rate and clarify the uptake process of trace elements in relation to the growth of the carbonate axis, Japanese red coral (Corallium japonicum) was cultured at a depth of 135 m off Takeshima Island, Kagoshima, Japan for 98 months and analyzed by microscopic X-ray fluorescence/soft X-ray photoabsorption (µ-XRF/XAS) speciation mapping. The growth rate was estimated to be 0.37 mm/year in diameter, and 10–11 growth rings were observed in a cross section of the axis. This estimated growth-rate value is the first ever to be obtained from the in-situ culture of Japanese precious coral. The fluctuation in water temperature near the in-situ-culture site was recorded for part of the culture period and then compared with the changes in the growth ring and the distribution of trace elements in a cross section of the coral axis during the same period. When the water temperature was increasing, the growth ring was light in color, sulfur and phosphorus concentrations were low, and magnesium was high. Conversely, a dark band in the growth ring, high sulfur and phosphorus, and low magnesium concentrations were observed when the water temperature was decreasing. In a cross section of the coral axis, the distribution of sulfur and magnesium from the center to the surface corresponded, respectively, to dark and light bands in the annual growth ring. Sulfur concentration was high in the dark band and low in the light band, while magnesium was negatively correlated with sulfur.
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Faizah, Ria, Lilis Sadiyah e Aisyah Aisyah. "Struktur Komunitas dan Preferensi Habitat Ikan Karang pada Terumbu Buatan di Teluk Awang dan Teluk Bumbang, Pulau Lombok". Oseanologi dan Limnologi di Indonesia 5, n. 1 (9 luglio 2020): 61. http://dx.doi.org/10.14203/oldi.2020.v5i1.202.
Abstract (sommario):
<strong>Community Structure and Habitat of Coral Fish on Artificial Reef in Awang and Bumbang Bay, Lombok Island</strong>. Artificial reefs which were placed in Teluk Awang and Teluk Bumbang intended to restore habitat fish resources. This paper aims to evaluate the development of artificial reefs in both locations. The activities was conducted in June and December 2015. Data collection included fish and benthic communities, biological parameters (phytoplankton, zooplankton, meroplanton), physical parameters (temperature, salinity, conductivity, pH, turbidity, dissolved oxygen), and chemical parameters waters (nitrates and phosphates). Observation of fish community using SCUBA diving equipment, underwater sheets, stationery and GPS, then visual observations using a modified stationary visual census technique. Visual recorded also used for benthic communities. Water sampling taken on the surface and bottom at depths of 9 m and 11 m using water quality checker. Biological parameters were taken using 60 µ, 300 µ and plankton net sizes 700 µ. Nutrients were observed in the laboratory by taking water samples in situ. Laboratory tests were carried out for nutrients as well as plankton and meroplankton. Benthic communities were categorized into four life forms, namely live coral covered, dead coral, biota (algae and other biota) as well as the abiotic component. Habitat preferences identified through analysis of factors related to fish abundance by principal component analysis method. The results showed that on those artificial reefs in Awang and Bumbang Bay found as many as 8 - 16 species of coral fish belongs to 15 families, dominated by Apogonidae (Archamia fucata), Pomacentridae (Neopomacentrus cyanomos) and Phempherididae (Phempheris oulensis), ranges of the abundance 268 to1088 individual. The ecological index showed low to moderate type of diversity, the dominance index does not indicate the dominance of certain species and the evenness index indicated that the fish dispersal characteristic is quite flat. Fish habitat preference in Awang Bay supported by the presence of algae and other biota, nutrients, and salinity. While in Teluk Bumbang supported by the abundance of fito-zooplankton, dissolved oxygen, and turbidity
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Salomão, Marcella Q., Ana Luisa Hoffling-Lima, Nelson Sena, Bernardo T. Lopes, Jaime Guedes e Renato Ambrósio. "Enhanced Screening for Ectasia Risk: Multimodal Refractive Imaging Observations From the Fellow Unoperated Eye of Patients With Post-Laser In Situ Keratomileusis Ectasia". Cornea Open 3, n. 1 (31 gennaio 2024): e0023. http://dx.doi.org/10.1097/coa.0000000000000023.
Abstract (sommario):
Purpose: The aim of this study was to report multimodal refractive imaging findings that may predict ectasia susceptibility on nonoperated eyes of patients who developed post-LASIK ectasia in the fellow eye. Study Design: This is a retrospective case series. Methods: The nonoperated fellow eyes of 5 patients who had unilateral LASIK with progressive ectasia underwent a comprehensive ophthalmologic evaluation and multimodal refractive imaging (MRI), including Pentacam HR and Corvis ST (Oculus; Wetzlar, Germany), along with segmental OCT (RTVue; Optovue, Inc, Fremont, CA). Different objective indices and parameters from the Pentacam, Corvis ST, and OCT were analyzed. Results: None of the 5 cases showed ectasia detection on the Pentacam TKC (topographic keratoconus classification), and inferior–superior (IS) asymmetry values were lower than 1.0 D in all 5 cases. Corneal thicknesses at the thinnest points measured with the Pentacam were 530, 466, 517, 488, and 511 µ, and with the OCT were 512, 460, 508, 480, and 495 µ, in cases 1to 5, respectively. The keratoconus risk scoring system based on OCT measurements demonstrated a high risk in 2 patients. The BAD-D (Belin-Ambrósio Enhanced Ectasia Deviation) was higher than 1.22 in all 5 cases and higher than 1.6 in 2 cases. Four cases had ARTmax (Ambrósio Relational Thickness to the meridian with maximal progression increase) lower than 390. The PRFI (Pentacam Random Forest Index) was equal or higher than 0.12 in all 5 cases, and enhanced posterior elevation, which is calculated using data from the standard elevation map, excluding a 3.5-mm area centered on the thinnest point, was abnormal in all 5 cases. The value of the current version of the tomographic biomechanical index (TBI V1), derived from artificial intelligence (AI) algorithms, which integrate Scheimpflug-based tomography and biomechanical data, was equal or higher than 0.29 in 3 cases. Conclusions: Signs of ectasia susceptibility were detected in all nonoperated eyes based on multimodal imaging. These findings support the clinical relevance of such analysis when screening for ectasia risk among candidates for refractive surgery.
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Carvalho, Denise A. M., Vânia C. Pinto, Paulo J. Sousa, Vitor H. Magalhães, Emilio Fernández, Pedro A. Gomes, Graça Minas e Luís M. Gonçalves. "Methodology for Phytoplankton Taxonomic Group Identification towards the Development of a Lab-on-a-Chip". Applied Sciences 12, n. 11 (26 maggio 2022): 5376. http://dx.doi.org/10.3390/app12115376.
Abstract (sommario):
This paper presents the absorbance and fluorescence optical properties of various phytoplankton species, looking to achieve an accurate method to detect and identify a number of phytoplankton taxonomic groups. The methodology to select the excitation and detection wavelengths that results in superior identification of phytoplankton is reported. The macroscopic analyses and the implemented methodology are the base for designing a lab-on-a-chip device for a phytoplankton group identification, based on cell analysis with multi-wavelength lighting excitation, aiming for a cheap and portable platform. With such methodology in a lab-on-a-chip device, the analysis of the phytoplankton cells’ optical properties, e.g., fluorescence, diffraction, absorption and reflection, will be possible. This device will offer, in the future, a platform for continuous, autonomous and in situ underwater measurements, in opposition to the conventional methodology. A proof-of-concept device with LED light excitation at 450 nm and a detection photodiode at 680 nm was fabricated. This device was able to quantify the concentration of the phytoplankton chlorophyll a. A lock-in amplifier electronic circuit was developed and integrated in a portable and low-cost sensor, featuring continuous, autonomous and in situ underwater measurements. This device has a detection limit of 0.01 µ/L of chlorophyll a, in a range up to 300 µg/L, with a linear voltage output with chlorophyll concentration.
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Mehra, Deepak, Manas Mohan Mahapatra e Suraj Prakash Harsha. "Effect of wear parameters on dry abrasive wear of RZ5-TiC in situ composite". Industrial Lubrication and Tribology 70, n. 2 (12 marzo 2018): 256–63. http://dx.doi.org/10.1108/ilt-12-2016-0306.
Abstract (sommario):
Purpose The purpose of this study is to increase the wear resistance of Mg alloy by adding hard ceramic particles to it. The inclusion of hard ceramic particles further strengthen the Mg alloy, resulting in higher wear resistance. Mg alloys containing Zn, rare earth and Zr exhibit high specific strength and excellent creep resistance, making them suitable for aerospace components such as aircraft gearboxes and generator housings. Design/methodology/approach In the present study, composites have been produced in situ by using RZ5 mg alloy as matrix and TiC as reinforcement by self-propagating high-temperature synthesis technique. The abrasive wear behavior of RZ5 Mg alloy matrix reinforced with TiC particulates has also been examined. The pin-on-disc apparatus has been used for the tests. The abrasive paper is used as a counter body, and the results are obtained by changing sliding distance and applied load. Findings A notable enhancement in the wear resistance and mechanical properties of tested composite has been observed as compared to the RZ5 Mg alloy as a matrix. There is a uniform increment in the change in weight loss of RZ5-TiC composite with increasing sliding distance and applied load, but it decreases with increasing TiC content. The coefficient of friction (µ) also decreases uniformly with an increase in the reinforcement of TiC, but it decreases with an increase in applied load and sliding distance. The investigation of the worn composite, which determines dominant wear mechanisms as abrasion and plowing grooves on tested samples, has been done using field emission scanning electron microscopy. Originality/value The current manuscript provides a detailed abrasive wear analysis of RZ5-TiC composite by using different wear parameters. Specifically, extensive experimental data have been provided for RZ5-TiC composite. The effects of parameters such as applied load, sliding distance and Wt.% of TiC on the weight loss and coefficient of friction of the composites have been analyzed and discussed thoroughly.
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Chennaram, S. Sharanya e T. Sonamani Singh. "Bidirectional Propulsion of Bioinspired Microswimmer in Microchannel at Low Reynolds Number". Journal of Physics: Conference Series 2663, n. 1 (1 dicembre 2023): 012035. http://dx.doi.org/10.1088/1742-6596/2663/1/012035.
Abstract (sommario):
Abstract Swimming of micro-scale bodies is different from macro-scale counterparts due to low Reynolds number (Re) fluid-swimmer interaction. The Re is defined as the ratio of inertial force to viscous force and it can be expressed as, Re =ρ𝑣𝑙/µ, where ρ and µ are the density and viscosity of the fluid medium, v and l are the velocity and length of the swimmer. For microswimmers, due to the small length scale Re < 1, the inertial forces are negligible compared to viscous forces. Unlike the macroscale swimmers which exploit the inertial force for locomotion, microswimmers must use a different strategy to propel in low Re condition. These strategies are already available and used by microorganisms, which are perfect low Re swimmers, for example, Spermatozoon exploits their tail flexibility and anisotropic drag to swim, and E. coli bacteria use their helical tail to generate a non-reciprocal motion. By mimicking these microswimmers, researchers have developed many bioinspired microswimmers/microrobots having the potential to perform biomedical tasks like drug delivery, cell manipulation, in-situ sensing, and detoxification. Theoretical modeling and simulation of microswimmers are generally done by assuming that the microswimmer is in an infinite fluid medium, but the type of biomedical applications aimed are in confined environments with boundaries. Also, the environments are very complex, and it requires precise control and efficacy. In this paper, we present the modeling of flagellated magnetic microswimmer (inspired by Spermatozoon) in a microchannel using the finite element method. The dynamics were simulated by incorporating the complete hydrodynamic interactions (HI), that is intra-HI between the parts of the swimmer and inter-HI between the swimmer and the boundary walls of the channel. The parametric dependence analysis reveals that swimmer kinematics are dependent on the length and width of the tail, the head radius, width of the channel, and the actuation frequency of the driving magnetic field. These dependencies are explored to find a navigation control mechanism for the propulsion of microswimmer in a channel.
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Pourbahman, Fatemeh, Mohsen Zeeb, Amirhossein Monzavi, Zahra Khodadadi e Seyed Saied Homami. "Reusable and sustainable graphene oxide/metal–organic framework-74/Fe3O4/polytyramine nanocomposite for simultaneous trace level quantification of five fluoroquinolones in egg samples by high performance liquid chromatography". Analytical Methods in Environmental Chemistry Journal 4, n. 02 (28 giugno 2021): 5–24. http://dx.doi.org/10.24200/amecj.v4.i02.135.
Abstract (sommario):
A nanohybrid material termed graphene oxide/metal-organic framework-74/Fe3O4/polytyramine (GO/MOF-74/Fe3O4/PTy) was fabricated and applied in magnetic dispersive micro-solid phase extraction (MD-µ-SPE) coupled with high performance liquid chromatography (HPLC) for simultaneous determination of fluoroquinolones compounds including, ofloxacin, ciprofloxacin, lomefloxacin, enrofloxacin and sperfloxacin in egg samples. The GO/MOF-74/Fe3O4/PTy nanocomposite was fabricated through an in situ synthesis of MOF-74 in the presence of magnetic GO and followed with an oxidative polymerization of tyramine using horsedish peroxide (HRP) enzyme. The modifier agents improved the merits of the nanoporous sorbent. Extraction protocols based on GO/MOF nanocomposites have various benefit such as, the high stability, the tunable porosity, the fast mast transfer and reasonable enrichment factor. The fabricated material was characterized via energy dispersive x-ray analysis (EDX), the scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and the x-ray diffraction (XRD). The calibration curves revealed linearity (0.992 ≤ r2 ≤ 0.997) in the ranges of 1.0-475.0, 0.5-350.0, 0.5-350.0, 0.5-375.0 and 1.5-300.0 ng mL-1 with limit of detections (LODs, S/N=3) of 0.3, 0.1, 0.2, 0.1 and 0.4 ng mL-1 for ofloxacin, ciprofloxacin, lomefloxacin, enrofloxacin and sperfloxacin, respectively. The intra-assay (≤7.7%, n = 9) and inter-assay (≤7.0%, n = 9) precisions along with accuracy less than 9.0% were obtained.
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Sedlmeier, Christian, Carina Schramm, Robin Schuster, Lennart Reuter e Hubert Andreas Gasteiger. "A Micro-Reference Electrode for Impedance and Potential Measurements in All-Solid-State Battery Pouch Cells". ECS Meeting Abstracts MA2022-01, n. 2 (7 luglio 2022): 207. http://dx.doi.org/10.1149/ma2022-012207mtgabs.
Abstract (sommario):
Electrochemical impedance spectroscopy (EIS) is a powerful and versatile tool to investigate interfaces in batteries. In order to disentangle the anode and cathode contributions from the full-cell impedance, a reference electrode (RE) is required. In the field of batteries based on liquid electrolytes, the concept of a RE has become a widespread tool for the EIS analysis of small-scale cells [1]. However, there are only very few reports on the use of a three-electrode setup with a reference electrode for all-solid-state batteries (ASSBs) [2,3], which is due to the complexity of integrating a RE with a suitable geometry in the typical ASSB test cells that are based on a compressed electrolyte pellet (further on referred to as bulk-type ASSB cells), since for artifact-free single-electrode impedance spectra, the RE should be placed between the electrodes and should be thin compared to the thickness of the pellet. In contrast to the widely used bulk-type ASSB cells, a recently available alternative construction is offered by the use of free-standing separator sheets based on a solid electrolyte / polymer binder composite (further on referred to as sheet-type ASSB cells),[4,5] in which case a micro-RE can be placed between two separator sheets, in analogy to the micro-RE concept used with batteries based on liquid electrolytes [1]. In this study, we use sheet-type separators based on a composite consisting of Li6PS5Cl (LPSCl) solid electrolyte and a hydrogenated nitrile butadiene rubber (HNBR) binder to build ASSB pouch cells that include a gold wire micro-RE (µ-GWRE). We show that upon in-situ lithiation of the µ-GWRE a stable reference potential is obtained and that artifact-free single-electrode impedance spectra can be obtained, analogous to what we had found previously for a µ-GWRE in a lithium ion battery with liquid electrolyte.[1] Figure 1 shows both half-cell impedance spectra of an InLi | separator sheet | Li cell. The sum of both half-cell impedances (blue) is identical to the full-cell impedance (green) and now impedance loops or other common artefacts are observed for the InLi (black) and the Li (red) electrodes, indicating the viability of this setup to determine single-electrode impedances. Since the InLi electrode is commonly used as counter electrode (CE) for ASSB testing cells, we will also use this setup to investigate the potential stability of InLi alloys and their impedance evolution upon lithiation and delithiation. Acknowledgements: This work was carried out as part of the research project “Industrialisierbarkeit Festkörperelektrolytzellen”, funded by the Bavarian Ministry of Economic Affairs, Regional Development and Energy. References: [1] Solchenbach, D. Pritzl, E. J. Y. Kong, J. Landesfeind and H. A. Gasteiger, J. Electrochem. Soc., 163 (10) A2265-A2272 (2016). [2] Dougas, Y. Dupraz, E. Quemin, T. Koc, and J.-M. Tarascon, J. Electrochem. Soc., 168 (9), 090508 (2021). [3] J. Nam, K. H. Park, D. Y. Oh, W. H. An and Y. S. Jung, J. Mater. Chem., 6, 14867-14875 (2018). [4] Riphaus, P. Strobl, B. Stiaszny, T. Zinkevich, M. Yavuz, J. Schnell, S. Indris, H. A. Gasteiger and S. Sedlmaier, J. Electrochem. Soc., 165 (16) A3993-A3999 (2018). [5] Sakuda, K. Kuratani, M. Yamamoto, M. Takahasi, T. Takeuchi and H. Kobayashi, J. Electrochem. Soc., 164 (12) A2474-A2478 (2017). Figure 1: Impedance Spectra of an InLi | separator sheet | Li pouch cell (4 cm2 electrode area) with a µ-GWRE recorded at open circuit voltage (OCV) with a voltage amplitude of 10 mV between 100 kHz and 100 mHz. The half-cell impedance spectra of the InLi working electrode (WE) and of the Li counter electrode (CE) are displayed in black and red, respectively. The sum of the individual half-cell impedance spectra (blue) matches with the full-cell impedance spectrum (green). The separator sheet is a » 400 µm thick composite of LPSCl and HNBR and no impedance loops are observed, demonstrating the successful implementation of the RE. Figure 1
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Walters, Clifford C. "Organic geochemistry at varying scales: from kilometres to ångstroms". Geological Society, London, Special Publications 484, n. 1 (12 settembre 2018): 121–37. http://dx.doi.org/10.1144/sp484.7.
Abstract (sommario):
AbstractPetroleum geochemistry has historically relied on the analysis of field samples – source rocks, oils and gases. Data collected for individual samples are considered characteristic of a specific geographical location and geological position that, when aggregated with data from other samples, can be extrapolated to larger scales. These scale-ups may be as small as a few metres, such as a detailed characterization of source rocks penetrated by a single well, to global, such as petroleum systems that now span continents due to plate tectonics. However, a single sample contains a wealth of information at smaller scales. In situ analytical techniques have improved significantly over the last decade, allowing us to examine sedimentary rocks at ever higher spatial (areal and temporal) resolution. Mass spectrometric imaging is an emerging, enabling technology that can be performed at c. 200 µm (matrix-assisted laser desorption) to 50 nm (nanoSIMS) resolution. X-ray microcomputed tomography (µ-CT) is being applied to examine the storage and transport of petroleum in low-permeability shales and carbonates at spatial resolutions as low as c. 8 µm. Pore architecture in shale, both organic and inorganic, can be modelled from small-angle neutron scattering (SANS) data and imaged directly with helium ion microscopy at c. 1 nm resolution. Atomic force microscopy (AFM) can now resolve the molecular structure of individual asphaltene molecules. Information obtained with these techniques is now revealing the fundamental nature of geological organic materials, opening the span of petroleum geochemistry from atoms to continents.
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Kalyani, Kalkhanday, Vinay Jaiswal, Rashmi Bala Rastogi e Devendra Kumar. "Synergistic studies of Schiff base with organoborate as efficient antiwear lubricant additive". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 231, n. 3 (5 agosto 2016): 357–65. http://dx.doi.org/10.1177/1350650116658598.
Abstract (sommario):
Schiff base derived from condensation of 4-aminotriazole with indole-3-carboxylaldehyde has been characterized by Fourier-transform infrared and 1H NMR spectroscopic techniques. The tribological properties of synthesized Schiff base have been evaluated using four-ball tester at optimized concentration (1% w/v) and compared with its individual components. The tribological testing has been performed by varying load for 30 min duration and varying test durations at 392 N load. The synergistic action of Schiff base with commercial borate ester effectively enhances the antiwear properties of base oil and its load-carrying capacity. Pronounced reduction in the values of mean wear scar diameter, friction coefficient (µ), mean wear volume (MWV), and wear rates confirm the synergistic interaction between Schiff base and borate ester. The best tribological properties are shown by synergistic mixture, followed by Schiff base, then indole-3-carbaldehyde, and finally 4-aminotriazole. The surface topography of worn surfaces has been studied by scanning electron microscopy and contact mode atomic force microscopy which show the drastic decrease in surface roughness in the presence of synergistic mixture. The energy-dispersive X-ray analysis of worn surface lubricated with synergistic formulation exhibits nitrogen, carbon, boron, and oxygen indicating the adsorption of additive on the metal surface to form in situ protective tribofilms, which prevent direct metal–metal contact thus reducing friction and wear. The quantum chemical calculations studies show that there is significant interaction of Schiff base additive with the metal surface than those of its individual components and the data correlate very well with the obtained tribological results.
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Schmatz, Joyce, Jop Klaver, Mingze Jiang e Janos L. Urai. "Nanoscale Morphology of Brine/Oil/Mineral Contacts in Connected Pores of Carbonate Reservoirs: Insights on Wettability From Cryo-BIB-SEM". SPE Journal 22, n. 05 (6 febbraio 2017): 1374–84. http://dx.doi.org/10.2118/180049-pa.
Abstract (sommario):
Summary We used broad-ion-beam slope cutting in combination with scanning electron microscopy undertaken under cryogenic conditions (Cryo-BIB-SEM) to study mineral/oil/brine contacts in reservoir carbonates. This direct-imaging method allows pore-scale investigation of in-situ fluids and their distributions down to the nanometer scale. In this study, we compare two types of carbonate reservoirs: a fine-grained Lixhe limestone (Belgium) and a coarse-grained limestone from the Maastricht area (The Netherlands). In both rock types, we first quantify the porosity with BIB-SEM and derive the spatially resolved pore connectivity of the rock from BIB-SEM on Wood's Metal (WM) injected subsamples. In the second step, subsamples were saturated with the oil analog n-hexadecane, and then flooded with NaCl brine and MgSO4 brine, respectively, to study the effect of the brine chemistry on the microscopic fluid distribution. Cryo-BIB-SEM in combination with high-resolution energy-dispersive-spectroscopy (EDS) imaging and automated image analysis on the saturated samples allowed for a quantification of the oil-droplet size, the lengths of carbonate/oil interfaces, and the 2D contact angle of carbonate with brine and oil. Our results show that these features (e.g., interface length, contact angles, effect of asperities) are present on the scale of a few tens of nanometers to a few micrometers, which is in agreement with numerous theoretical and experimental studies. Lixhe limestone showed relatively less carbonate/oil contacts despite a larger oil fraction in the MgSO4-brine-flooded sample compared with the sample flooded with NaCl brine, indicating a more-hydrophilic nature of the carbonate surface in this experiment. This feasibility study showed that the technique permits the testing of predictions on the morphology and dynamics of contact lines in relation to the mineral properties, which is not possible with other imaging methods, such as X-ray microcomputed tomography (µ-CT), because of limits in resolution.
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Janssen, Marek, Jonathan Quinson, Jakub Drnec, Isaac Martens, Rebecca Katharina Pittkowski, Daseung Park, Matthias Singer, Philipp Weber, Matthias Arenz e Mehtap Oezaslan. "Monitoring the Particle Size Distribution, Phase Quantification and Chemical Composition of Acid-Leached PtCo Electrocatalyst Under Start-up/Shut-Down Conditions Probed By in-Situ SAXS and WAXS Techniques". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2223. http://dx.doi.org/10.1149/ma2023-01382223mtgabs.
Abstract (sommario):
Large progress has been made towards commercialization of polymer electrolyte membrane fuel cells (PEMFCs) through the development of highly active and robust Pt-Co alloy catalysts for oxygen reduction reaction (ORR).[1,2] However, most ORR catalyst materials suffer from the extremely corrosive conditions occurring during start-up/shut-down (SUSD).[3] Consequently, understanding the degradation mechanisms during SUSD is highly crucial for designing new catalyst materials with enhanced ORR activity and long-term durability. In this work, we show a comprehensive and complementary combination of different advanced techniques such as in-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) as well as ex-situ scanning transmission electron microscopy in combination with electron energy loss spectroscopy (STEM-EELS) to provide deeper insights into the degradation processes of acid-leached Pt-Co catalyst under SUSD conditions. Firstly, Pt-Co nanoparticles supported on high surface area carbon (HSAC) were synthesized using wet impregnation – freeze-drying – thermal annealing method.[4] Compared to our previous works [4-6], an acid-leaching (1 M H2SO4, 15 °C, 2 h) was applied to dissolve the less noble metal from the surface of alloy nanoparticles forming a Pt-enriched skin. STEM-EELS data has also confirmed the formation of the Pt-enriched skin. In addition, ex-situ WAXS data signifies that the acid-leached PtCo catalyst consists of two face-centered cubic (fcc) disordered crystal phases: Pt90Co10 phase with a crystallite size of 3.6 ± 0.4 nm and Pt70Co30 phase with 4.2 ± 0.4 nm size. In terms of ORR performance, the acid-leached PtCo catalyst exhibits a 2.5- & 2-times higher mass activity (0.61 ± 0.12 A mgPt -1) and a 3.5- and 1.3-times higher specific activity (665 ± 84 µA cmPt -2) at 0.9 VRHE compared to commercial ~2 nm Pt/C (0.24 ± 0.05 A mgPt -1, 187 ± 29 µA cmPt -2) and heat-treated 4-5 nm Pt/HSAC (0.30 ± 0.04 A mgPt -1, 297 ± 42 µA cmPt -2), respectively. After SUSD experiments (800 cycles, 0.5 - 1.5 VRHE, 50 mV s-1, 0.1 M HClO4), the mass activity decreases to 0.21 ± 0.06 A mgPt -1 (-65 %) and 0.15 ± 0.03 A mgPt -1 (-38 %) for the acid-leached PtCo catalyst and commercial Pt/C, respectively. To monitor the potential-dependent changes in particle/crystallite size, phase quantification and chemical composition of the acid-leached PtCo catalyst under the SUSD conditions, in-situ SAXS and WAXS experiments were simultaneously performed at the beamline ID31 at European Synchrotron Radiation Facility (ESRF). In-situ WAXS analysis reveals that the lattice parameter of both Pt90Co10 and Pt70Co30 phases increases as a function of the SUSD cycle number, signifying the successive depletion of cobalt mainly from the Pt70Co30 phase. More precisely, the lattice parameter changed from 3.819 ± 0.004 Å (Pt70Co30) to 3.829 ± 0.004 Å (Pt76Co24) during the first 150 SUSD cycles. Only a slight change in lattice parameter for Pt90Co10 phase is observed during the SUSD protocol. Based on the Rietveld quantification, the amount of the Pt70Co30 phase decreases from 61 ± 2 wt.% to 47 ± 2 wt.% during the first 150 SUSD cycles. Afterwards, the Co depletion from this phase is less pronounced with additional cycle number. Furthermore, STEM-EELS investigations on acid-leached PtCo catalyst after first 150 SUSD cycles has confirmed the drastic Co depletion within the nanoparticles. After the SUSD protocol, the chemical composition of the acid-leached PtCo catalyst alters from Pt67±3Co33±3 to Pt81±3Co19±3 (-42 at.%) obtained from the bulk techniques like EDX and µ-XRF. In addition, the Rietveld refinement reveals an increase in crystallite sizes for both Pt-Co crystal phases over the course of the SUSD protocol which is in excellent agreement to the in-situ SAXS and ex-situ TEM results (from 4.1 ± 1.0 nm to 5.2 ± 0.8 nm, +27 %). In detail, the initial larger Pt70Co30 phase shows only a small increase in crystallite size (from 4.3 ± 0.4 nm to 4.8 ± 0.4 nm, +12 %), whereas for the initial smaller Pt90Co10 phase a gradual increase from 3.2 ± 0.3 nm to 4.5 ± 0.4 nm (+41 %) is observed during the SUSD experiment. Based on the in-situ SAXS/WAXS and the ex-situ STEM-EELS data, the Co depletion is the dominant degradation mechanism for the disordered fcc Pt70Co30 phase during the first 150 SUSD cycles. With increasing SUSD cycle number, the particle growth via Ostwald ripening and particle coalescence predominates. Our degradation model can be used to further improve the ORR performance and durability of acid-leached Pt-Co catalysts under the SUSD conditions. Literature: [1] L.R.Borup et al.,Curr.Opin.Electrochem.,2020,21,192-200. [2] C.Wang et al.,Energies,2016,9,603-642. [3] Y.Yu, et al.,J.Power Sources,2012,205,10-23. [4] M.Oezaslan et al.,J.Electrochem.Soc.,2012,159,B394-B405. [5] D.J.Weber et al.,J.Mater.Chem.A,2021,9,15415-15431. [6] P.Weber et al.,ACS Catal.,2022,12,6394-6408.
16
Belissont, Rémi, Manuel Munoz, Marie-Christine Boiron, Béatrice Luais e Olivier Mathon. "Germanium Crystal Chemistry in Cu-Bearing Sulfides from Micro-XRF Mapping and Micro-XANES Spectroscopy". Minerals 9, n. 4 (12 aprile 2019): 227. http://dx.doi.org/10.3390/min9040227.
Abstract (sommario):
Germanium is considered a critical element, with a demand that has sharply increased due to booming high-technology industries. To understand Ge incorporation mechanisms in natural systems, we investigate Ge speciation in Cu-bearing sulfide minerals using synchrotron X-ray fluorescence (XRF) chemical mapping and Ge K-edge µ-X-ray absorption near-edge structures (µ-XANES) spectroscopy. The samples investigated include (i) a homogeneous chalcopyrite from the Kipushi polymetallic deposit (Central African copperbelt, D.R. Congo) and (ii) a zoned Ge-rich chalcopyrite from the Barrigão Cu deposit (Iberian pyrite belt, Portugal). First, our spectroscopic analysis supports the occurrence of tetrahedrally-coordinated Ge4+ in chalcopyrite, independently from origins or zoning patterns observed for these minerals. Then, based on statistical analyses of XRF chemical maps, we demonstrate that tetravalent germanium most likely incorporates chalcopyrite through the Fe crystallographic site via coupled substitutions with the following form: (2x + 3y)Fe3+ ⟷ (x + 2y)(Ge,Sn)4+ + x(Zn,Pb)2+ + y(Cu,Ag)+, although the presence of lattice vacancies cannot be completely excluded.
17
Li, Zoe, Jie Liu, Fan Dong, Nancy Chang, Ruili Huang, Menghang Xia, Tucker A. Patterson e Huixiao Hong. "Three-Dimensional Structural Insights Have Revealed the Distinct Binding Interactions of Agonists, Partial Agonists, and Antagonists with the µ Opioid Receptor". International Journal of Molecular Sciences 24, n. 8 (11 aprile 2023): 7042. http://dx.doi.org/10.3390/ijms24087042.
Abstract (sommario):
The United States is experiencing the most profound and devastating opioid crisis in history, with the number of deaths involving opioids, including prescription and illegal opioids, continuing to climb over the past two decades. This severe public health issue is difficult to combat as opioids remain a crucial treatment for pain, and at the same time, they are also highly addictive. Opioids act on the opioid receptor, which in turn activates its downstream signaling pathway that eventually leads to an analgesic effect. Among the four types of opioid receptors, the µ subtype is primarily responsible for the analgesic cascade. This review describes available 3D structures of the µ opioid receptor in the protein data bank and provides structural insights for the binding of agonists and antagonists to the receptor. Comparative analysis on the atomic details of the binding site in these structures was conducted and distinct binding interactions for agonists, partial agonists, and antagonists were observed. The findings in this article deepen our understanding of the ligand binding activity and shed some light on the development of novel opioid analgesics which may improve the risk benefit balance of existing opioids.
18
Pelosi, Claudia, Filomena Di Stasio, Luca Lanteri, Martina Zuena, Marta Sardara e Armida Sodo. "The “Restoration of the Restoration”: Investigation of a Complex Surface and Interface Pattern in the Roman Wall Paintings of Volsinii Novi (Bolsena, Central Italy)". Coatings 14, n. 4 (29 marzo 2024): 408. http://dx.doi.org/10.3390/coatings14040408.
Abstract (sommario):
(1) Background: The present paper reports the results of the analyses performed on the wall paintings of Room E of the Domus delle Pitture (Room of the Paintings) in the Roman archaeological site of Volsinii Novi (Bolsena, Viterbo, Central Italy) aimed at supporting the recently concluded restoration. (2) Methods: ultraviolet fluorescence photography was conducted to evaluate the conservation state. Painting materials were investigated via portable X-ray fluorescence spectrometer (p-XRF), µ-Raman spectroscopy, cross-section analysis under polarizing microscope, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared (FTIR) spectroscopy. (3) Results: This analysis revealed the presence of traditional pigments used in Roman wall paintings, such as ochres, earths, and Egyptian blue. Additionally, it identified pigments from previous restoration containing titanium and chromium, along with other materials present in the surface and interface of the wall painting containing arsenic, copper, lead, and vanadium, where a bluish alteration was observed. In these samples, µ-Raman spectroscopy detected calcium oxalates but also copper arsenates, likely conichalcite and/or duftite. (4) Conclusions: This result is highly relevant from an analytical point of view and in relation to the restoration decisions. Addressing the irregular bluish stains on the wall paintings poses challenges in understanding, requiring a decision on whether to remove or retain them.
19
Turner, R. Eugene, e Yu Mo. "Salt Marsh Elevation Limit Determined after Subsidence from Hydrologic Change and Hydrocarbon Extraction". Remote Sensing 13, n. 1 (25 dicembre 2020): 49. http://dx.doi.org/10.3390/rs13010049.
Abstract (sommario):
Levee construction aboveground and hydrocarbon removal from belowground in coastal wetlands can create hydrologic changes that increase plant stress through flooding. But the significance of the subsidence they cause individually or in combination is contested. This study untangled them to demonstrate elevational limits of salt marshes by studying dredged and natural waterways in two salt marshes in Louisiana, USA. The areas had a homogenous plant cover before drilling for oil and gas extraction peaked in the 1960s, and now are a mixed network of natural waterways and dredged canals used to drill wells with an average drill date of 1965.8 ± 2.7 (µ ± 1 SEM; n = 18) and well depth of 4661.0 m ± 56.6 (µ ± 1 SEM; n = 18). Aerial imagery was used to document how canals widened to become 2 to 4 times larger than their original construction width at the high production site and 50% larger at the low production site, whereas increases at the nearby natural channels were much less. Light detection and ranging (LIDAR) measurements at the high production site from 2002 showed that the marsh surface near wells subsided by 34 cm compared to undredged sites. Elevation in marshes at producing and dry wells were equal at the low production site, but high production well locations were even lower than at dry wells. An elevation vs. percent open water curve developed from these data overlapped with an independent analysis of a brackish marsh. A relative subsidence rate between 7.4 to 10.4 mm y−1 transformed these salt marshes to an open water habitat within a few decades. The local creation of accommodation space through hydrocarbon removal and leveed wetlands is a parsimonious explanation for the spatial and temporal land loss rates on this deltaic coast over the last 80 years of oil and gas exploration. Substantial losses from the accelerating rates of sea level rise are indicated to occur before 2050.
20
Sarti, Maurizio, Francesco Primo Vaccari, Carlo Calfapietra, Enrico Brugnoli e Andrea Scartazza. "A Statistical Approach to Detect Land Cover Changes in Mediterranean Ecosystems Using Multi-Temporal Landsat Data: The Case Study of Pianosa Island, Italy". Forests 11, n. 3 (17 marzo 2020): 334. http://dx.doi.org/10.3390/f11030334.
Abstract (sommario):
The normalized difference vegetation index (NDVI) is commonly used to detect spatiotemporal changes of vegetation cover. This study modeled the spatiotemporal changes of land cover on Pianosa Island, Italy, in the period 1999–2015, using the multi-temporal Landsat images. Since the end of the 1990s, the natural vegetation has been re-colonizing an area of abandoned agricultural land and the island is undergoing a process of re-naturalization in harsh (drought and hot) environmental conditions. Hence, it is an ideal test site to monitor the effects of anthropogenic and climatic stressors on vegetation dynamics under Mediterranean climate. In this work, we proposed a new statistical approach based on a pixel-by-pixel analysis of multi-temporal Landsat images. Mean (µ) and standard deviation (σ) values of the NDVI images taken in 2015 were used for the determination of the pixel thresholds (µ ± 3σ). The evaluation of land cover change was carried out by comparing the µ value of a single NDVI pixel for 2015 with the same pixel of different years of the study period. The results indicate that surface reflectance (SR) Landsat images are more suitable in detecting the vegetation dynamics on the island than the top of atmosphere (TOA) ones and highlight an increasing trend of vegetation cover on Pianosa Island, mainly during the early seven years following the land abandonment in all the main land cover classes: abandoned crops and pastures, Mediterranean macchia, and woodland. However, the abandoned agricultural and pasture areas showed a higher increase in the vegetation cover and a shift in the shape of the normalized frequency distribution of the SR NDVI data during the study period, suggesting that a colonization process from other vegetation classes is occurring (i.e., Mediterranean macchia and trees are colonizing the abandoned land, partly replacing herbaceous species). Our data highlight that the statistical approach applied in this study is suitable for detecting vegetation cover changes associated with anthropogenic and climatic drivers in a typical Mediterranean environment and could be proposed as a new methodological approach in several other land monitoring studies.
21
Park, Ki Suk, Ralf Milke, Erik Rybacki e Sabine Reinhold. "Application of Image Analysis for the Identification of Prehistoric Ceramic Production Technologies in the North Caucasus (Russia, Bronze/Iron Age)". Heritage 2, n. 3 (6 agosto 2019): 2327–42. http://dx.doi.org/10.3390/heritage2030143.
Abstract (sommario):
The recent advances in microscopy and scanning techniques enabled the image analysis of archaeological objects in a high resolution. From the direct measurements in images, shapes and related parameters of the structural elements of interest can be derived. In this study, image analysis in 2D/3D is applied to archaeological ceramics, in order to obtain clues about the ceramic pastes, firing and shaping techniques. Images were acquired by the polarized light microscope, scanning electron microscopy (SEM) and 3D micro X-ray computed tomography (µ-CT) and segmented using Matlab. 70 ceramic sherds excavated at Ransyrt 1 (Middle-Late Bronze Age) and Kabardinka 2 (late Bronze–early Iron Age), located in in the North Caucasian mountains, Russia, were investigated. The size distribution, circularity and sphericity of sand grains in the ceramics show site specific difference as well as variations within a site. The sphericity, surface area, volume and Euler characteristic of pores show the existence of various pyrometamorphic states between the ceramics and within a ceramic. Using alignments of pores and grains, similar pottery shaping techniques are identified for both sites. These results show that the image analysis of archaeological ceramics can provide detailed information about the prehistoric ceramic production technologies with fast data availability.
22
Landeros-Martínez, Linda-Lucila, Mara Ibeth Campos-Almazán, Nora-Aydeé Sánchez-Bojorge, Raul Flores, Juan Pedro Palomares-Báez e Luz María Rodríguez-Valdez. "Theoretical Studies for the Discovery of Potential Sucrase-Isomaltase Inhibitors from Maize Silk Phytochemicals: An Approach to Treatment of Type 2 Diabetes". Molecules 28, n. 19 (23 settembre 2023): 6778. http://dx.doi.org/10.3390/molecules28196778.
Abstract (sommario):
A theoretical analysis of the potential inhibition of human sucrase-isomaltase (SI) by flavonoids was carried out with the aim of identifying potential candidates for an alternative treatment of type 2 diabetes. Two compounds from maize silks, maysin and luteolin, were selected to be studied with the structure-based density functional theory (DFT), molecular docking (MDock), and molecular dynamics (MD) approaches. The docking score and MD simulations suggested that the compounds maysin and luteolin presented higher binding affinities in N-terminal sucrase-isomaltase (NtSI) than in C-terminal sucrase-isomaltase (CtSI). The reactivity parameters, such as chemical hardness (η) and chemical potential (µ), of the ligands, as well as of the active site amino acids of the NtSI, were calculated by the meta-GGA M06 functional in combination with the 6-31G(d) basis set. The lower value of chemical hardness calculated for the maysin molecule indicated that this might interact more easily with the active site of NtSI, in comparison with the values of the acarbose and luteolin structures. Additionally, a possible oxidative process was proposed through the quantum chemical calculations of the electronic charge transfer values (∆N) between the active site amino acids of the NtSI and the ligands. In addition, maysin displayed a higher ability to generate more oxidative damage in the NtSI active site. Our results suggest that maysin and luteolin can be used to develop novel α-glucosidase inhibitors via NtSI inhibition.
23
Landeros-Martínez, Linda-Lucila, Néstor Gutiérrez-Méndez, Juan Pedro Palomares-Báez, Nora-Aydeé Sánchez-Bojorge, Juan Pablo Flores-De los Ríos, Hilda Amelia Piñón-Castillo, Marco Antonio Chávez-Rojo e Luz-María Rodríguez-Valdez. "The Oxidative Process of Acarbose, Maysin, and Luteolin with Maltase-Glucoamylase: Molecular Docking and Molecular Dynamics Study". Applied Sciences 11, n. 9 (29 aprile 2021): 4067. http://dx.doi.org/10.3390/app11094067.
Abstract (sommario):
Type 2 diabetes mellitus has been classified as the epidemic of the XXI century, making it a global health challenge. Currently, the commonly used treatment for this disease is acarbose, however, the high cost of this medicine has motivated the search for new alternatives. In this work, the maysin, a characteristic flavonoid from maize inflorescences, and its aglycon version, luteolin, are proposed as acarbose substitutes. For this, a theoretical comparative analysis was conducted on the molecular interactions of acarbose, maysin, and luteolin with human maltase-glucoamylase (NtMGAM), as well as their oxidative process. The binding energies in the active site of NtMGAM with acarbose, maysin, and luteolin molecules were predicted using a molecular docking approach applying the Lamarckian genetic algorithm method. Theoretical chemical reactivity parameters such as chemical hardness (η) and chemical potential (µ) of the acarbose, maysin, and luteolin molecules, as well as of the amino acids involved in the active site, were calculated using the electronic structure method called Density Functional Theory (DFT), employing the M06 meta-GGA functional in combination with the 6-31G(d) basis set. Furthermore, a possible oxidative process has been proposed from quantum-chemical calculations of the electronic charge transfer values (ΔN), between the amino acids of the active site and the acarbose, maysin, and luteolin. Molecular docking predictions were complemented with molecular dynamics simulations. Hence, it was demonstrated that the solvation of the protein affects the affinity order between NtMGAM and ligands.
24
Lee, Myung Ah, Guk Jin Lee, Ji Hyung Hong, Hee Yeon Lee e Sang Young Roh. "Use of high white blood cell (WBC) count to predict poor survival outcome in gastrointestinal (GI) cancer with thrombotic event." Journal of Clinical Oncology 30, n. 15_suppl (20 maggio 2012): e19614-e19614. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e19614.
Abstract (sommario):
e19614 Background: There are some known risk factors for deep vein thrombosis in cancer patients, such as primary site of cancer, white blood cell count (WBC), hemoglobin (Hb), platelet count (PLT). We investigated the association between these factors and the overall survival as prognostic factor in gastrointestinal (GI) cancer patients. Methods: All the patients with gastrointestinal cancer, who developed deep vein thrombosis or pulmonary thromboembolism through the clinical course, were retrospectively reviewed between January 2009 and June 2011 at Seoul St. Mary’s Hospital. According to treatment, patients were classified into two groups; the chemotherapy group and the supportive care group. Results: Of the fifty-six patients, median age was sixty three year-old. Stomach cancer was most common 35% , pancreatic cancer 31%, colorectal cancer 19%, and biliary cancer was 15%. There were three pattern of thrombosis: 19 (34%) deep vein thrombosis (DVT) only, 12 (21%) pulmonary thromboembolism (PTE) only, 25 (45%) combined DVT with PTE. WBC count above 11,000/µ° showed the poor overall survival than other group (median survival 3.4 months vs. 1.7 months, respectively, p=0.015) However, other risk factor did not show any significant association (Hb: p=0.521, PLT: p=0.295) In chemotherapy group, twelve (55%) patients had progressive disease and ten (45%) patients had stable disease at the time of thrombotic event. There was no statistically significant association between thrombosis and tumor response. The chemotherapy group had tendency of better survival outcome than the supportive care group without statistical significance (median survival 2.4 months vs. 5.3months, p=0.07). Conclusions: In GI cancer patients, elevated white blood cell count above 11,000/µ° can be important prognostic and risk factor for thrombosis with poor survival outcome. And the response of chemotherapy seemed to have no influence on thrombotic event during chemotherapy. This is very limited study due to small sample size and retrospective analysis, and heterogenous type of cancer. Further large study should be warranted to define the thrombotic risk factor as prognostic marker.
25
Freischmidt, Holger, Jonas Armbruster, Emma Bonner, Thorsten Guehring, Dennis Nurjadi, Maren Bechberger, Robert Sonntag, Gerhard Schmidmaier, Paul Alfred Grützner e Lars Helbig. "Systemic Administration of PTH Supports Vascularization in Segmental Bone Defects Filled with Ceramic-Based Bone Graft Substitute". Cells 10, n. 8 (11 agosto 2021): 2058. http://dx.doi.org/10.3390/cells10082058.
Abstract (sommario):
Non-unions continue to present a challenge to trauma surgeons, as current treatment options are limited, duration of treatment is long, and the outcome often unsatisfactory. Additionally, standard treatment with autologous bone grafts is associated with comorbidity at the donor site. Therefore, alternatives to autologous bone grafts and further therapeutic strategies to improve on the outcome and reduce cost for care providers are desirable. In this study in Sprague–Dawley rats we employed a recently established sequential defect model, which provides a platform to test new potential therapeutic strategies on non-unions while gaining mechanistic insight into their actions. The effects of a combinatorial treatment of a bone graft substitute (HACaS+G) implantation and systemic PTH administration was assessed by µ-CT, histological analysis, and bio-mechanical testing and compared to monotreatment and controls. Although neither PTH alone nor the combination of a bone graft substitute and PTH led to the formation of a stable union, our data demonstrate a clear osteoinductive and osteoconductive effect of the bone graft substitute. Additionally, PTH administration was shown to induce vascularization, both as a single adjuvant treatment and in combination with the bone graft substitute. Thus, systemic PTH administration is a potential synergistic co-treatment to bone graft substitutes.
26
Elshakre, Mohamed E., Mahmoud A. Noamaan, Hussein Moustafa e Haider Butt. "Density Functional Theory, Chemical Reactivity, Pharmacological Potential and Molecular Docking of Dihydrothiouracil-Indenopyridopyrimidines with Human-DNA Topoisomerase II". International Journal of Molecular Sciences 21, n. 4 (13 febbraio 2020): 1253. http://dx.doi.org/10.3390/ijms21041253.
Abstract (sommario):
In this work, three computational methods (Hatree-Fock (HF), Møller–Plesset 2 (MP2), and Density Functional Theory (DFT)) using a variety of basis sets are used to determine the atomic and molecular properties of dihydrothiouracil-based indenopyridopyrimidine (TUDHIPP) derivatives. Reactivity descriptors of this system, including chemical potential (µ), chemical hardness (η), electrophilicity (ω), condensed Fukui function and dual descriptors are calculated at B3LYP/6-311++ G (d,p) to identify reactivity changes of these molecules in both gas and aqueous phases. We determined the molecular electrostatic surface potential (MESP) to determine the most active site in these molecules. Molecular docking study of TUDHIPP with topoisomerase II α and β is performed, predicting binding sites and binding energies with amino acids of both proteins. Docking studies of TUDHIPP versus etoposide suggest their potential as antitumor candidates. We have applied Lipinski, Veber’s rules and analysis of the Golden triangle and structure activity/property relationship for a series of TUDHIPP derivatives indicate that the proposed compounds exhibit good oral bioavailability. The comparison of the drug likeness descriptors of TUDHIPP with those of etoposide, which is known to be an antitumor drug, indicates that TUDHIPP can be considered as an antitumor drug. The overall study indicates that TUDHIPP has comparable and even better descriptors than etoposide proposing that it can be as effective antitumor drug, especially 2H, 6H and 7H compounds.
27
Marussi, Giovanna, Matteo Crosera, Enrico Prenesti, Bruno Callegher, Elena Baracchini, Gianluca Turco e Gianpiero Adami. "From Collection or Archaeological Finds? A Non-Destructive Analytical Approach to Distinguish between Two Sets of Bronze Coins of the Roman Empire". Molecules 28, n. 5 (5 marzo 2023): 2382. http://dx.doi.org/10.3390/molecules28052382.
Abstract (sommario):
This study stems from the need for numismatics to establish whether there may be relationships between a group of 103 bronze coins from the Roman era found in archaeological excavations on the Cesén Mountain (Treviso, Italy) and a group of 117 coins kept at the Museum of Natural History and Archaeology in Montebelluna (Treviso, Italy). The chemists were delivered six coins with neither pre-agreements nor further information on the origin of the coins. Therefore, the request was to hypothetically assign the coins to the two groups on the basis of similarities and differences in their surface composition. Only non-destructive analytical techniques were allowed to be used to characterize the surface of the six coins taken blindly from the two sets. The elemental analysis of each coins’ surface was carried out by µ-XRF. To better observe the morphology of the coins’ surfaces, SEM-EDS was used. Compounds covering the coins coming from both corrosion processes (patinas) and the deposition of soil encrustations were also analyzed by means of the FTIR-ATR technique. The molecular analysis confirmed the presence of silico-aluminate minerals on some coins, unequivocally indicating a provenance from clayey soil. Some soil samples, collected from the archaeological site of interest, were analyzed to verify whether the encrusted layer on coins could contain chemical components compatible with them. This result, together with the chemical and morphological investigations, led us to subdivide the six target coins into two groups. The first group is made up of two coins coming from the set of coins from excavation (found in the subsoil) and from the set from open air finds (coins found in the top layer of the soil). The second group is made up of four coins that are devoid of characteristics corresponding to exposure to soil contact for long periods of time and, moreover, their surface compounds could suggest a different provenance. The analytical results of this study made it possible to correctly assign all six coins to the two groups of finds and support numismatics, which was unconvinced in considering all coins to come from the same finding site only on the basis of archaeological documentations.
28
Prochnow, Tyler, Megan S. Patterson, Logan Hartnell e M. Renée Umstattd Meyer. "Depressive symptoms associations with online and in person networks in an online gaming community: a pilot study". Mental Health Review Journal 25, n. 1 (5 marzo 2020): 21–33. http://dx.doi.org/10.1108/mhrj-11-2019-0044.
Abstract (sommario):
Purpose Increases in video game use have led to mental health concerns, citing greater risk for depressive symptoms (DS) and reduced “in-real-life” (IRL) social involvement. However, recent studies have uncovered potential social benefits for online gaming. Many games provide avenues to extend real life relationships and make new online friendships. The purpose of this pilot study is to use social network analysis to determine associations between connections and DS in a gaming community. Design/methodology/approach As a pilot study, members of an online gaming site were asked to report demographic characteristics, DS, IRL social support, online social support and IRL people and members of the online community with whom they spoke to about important life matters. Multi-level modeling was used to parse variance described by demographic characteristics, IRL measures and online measures. Linear network autocorrelation modeling (LNAM) was used to determine relationships between network connections and DS. Findings Members (n = 37; µ = 24.76 years old, SD = 6.55; 100% male; 89.2% white) on average felt DS’ “not at all” to “several days” over the past two weeks. Multi-level modeling including online network measures explained 50% of variance (R2 = 0.50, F (9,27) = 2.98, p = 0.01); online connections were associated with DS (ß = 0.46). LNAM indicated DS were associated with IRL support (ß = −2.66), IRL connections (ß = 1.81), online support (ß = 2.40) and network effects (ß = 0.06), which indicates that a gamer’s DS were similar to those of their online connections. Originality/value Members with more DS may be seeking help via online channels. This may be important for future research to consider alternative forms of help-seeking behavior.
29
Guimarães, Patrik, Ana Letycia Basso Garcia, Carla Costa Garcia, David Evandro Fernandes, Thiago Romanos Benatti, Aurelio Aguiar, Jose Luis Lima et al. "Genetic parameters for early growth and disease resistance in a cloned F2 hybrid progeny of Eucalyptus urophylla × grandis". Agrociencia Uruguay 27, NE2 (20 novembre 2023): e1255. http://dx.doi.org/10.31285/agro.27.1255.
Abstract (sommario):
The VERACEL breeding program includes several advanced generation urograndis hybrids (F2) from crosses of selected F1. To understand the performance and genetics of these F2, we established F2-cloned progeny trials with 1,350 clones from 35 families, each family with 8 to 35 cloned progenies. These families stem from crosses between known F1 urograndis female parents and pollen mixtures of other selected parents. The experimental design comprised 15 trials with 95 clones each, arranged in randomized blocks and linked by 7 common commercial hybrid clones. These experiments were performed in two sites contrasting for physiological disorder (PD) incidence. Due to incomplete pedigree of the families, the model fitted assumed the additive genetic relationship between sibs as half-sibs. The non-additive genetic component was estimated from clone effects within half-sib families. A multisite individual tree genetic model was fitted for diameter, height, PD, Calonectria, and rust incidence for trees up to 1 year old: yijklmn= µ+gi+gij+sm+cn+tbkl+sgim+sgijm+scmn+eijklmn; where random effects are gij (additive genetic effects), gi (all non-additive genetic effects of clones), and eijklmn (residuals); and fixed effects are sm, which is either site with higher or lower productivity and PD incidence, cn is F1 or F2, and tbkl is trial-block interaction. The same model was used for diseases and PD, but assumed a binomial distribution with a logit link function. PD was analysed only for the higher PD incidence site, thus excluding interactions with the other site. Results indicate that at the high PD incidence site, height and diameter growth was greater (~40%), but it also had higher mortality (40% vs. 22%) and higher PD incidence (51% vs. 23%). Compared with F1 controls, Calonectria incidence was higher in F2 (~10%) but similar at both sites, as was rust, although with lower incidence (~5%). Multisite analysis revealed low additive genetic variance and moderate total genetic variance (A+NA) for growth, diseases, and PD. For growth, narrow- and broad-sense heritability were h2=0.11 and H2=0.40. The additive genetic correlation between the two sites was close to 1 (rA~0.9), whereas the non-additive genetic correlation was lower (rNA~0.5). The narrow- and broad-sense heritability for diseases and PD was low (between 0.10 and 0.15). The low additive genetic variance for growth, diseases, and PD constrains substantial gains from parental selection within F1. However, clonal selection would still be effective due to considerable non-additive effects. Further studies using a large set of various populations are needed to validate these findings.
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Santana-Romo, Fabián, Carlos F. Lagos, Yorley Duarte, Francisco Castillo, Yanina Moglie, Miguel A. Maestro, Nitin Charbe e Flavia C. Zacconi. "Innovative Three-Step Microwave-Promoted Synthesis of N-Propargyltetrahydroquinoline and 1,2,3-Triazole Derivatives as a Potential Factor Xa (FXa) Inhibitors: Drug Design, Synthesis, and Biological Evaluation". Molecules 25, n. 3 (23 gennaio 2020): 491. http://dx.doi.org/10.3390/molecules25030491.
Abstract (sommario):
The coagulation cascade is the process of the conversion of soluble fibrinogen to insoluble fibrin that terminates in production of a clot. Factor Xa (FXa) is a serine protease involved in the blood coagulation cascade. Moreover, FXa plays a vital role in the enzymatic sequence which ends with the thrombus production. Thrombosis is a common causal pathology for three widespread cardiovascular syndromes: acute coronary syndrome (ACS), venous thromboembolism (VTE), and strokes. In this research a series of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives as a potential factor Xa (FXa) inhibitor were designed, synthesized, and evaluated for their FXa inhibitor activity, cytotoxicity activity and coagulation parameters. Rational design for the desired novel molecules was performed through protein-ligand complexes selection and ligand clustering. The microwave-assisted synthetic strategy of selected compounds was carried out by using Ullmann-Goldberg, N-propargylation, Mannich addition, Friedel-Crafts, and 1,3-dipolar cycloaddition type reactions under microwave irradiation. The microwave methodology proved to be an efficient way to obtain all novel compounds in high yields (73–93%). Furthermore, a thermochemical analysis, optimization and reactivity indexes such as electronic chemical potential (µ), chemical hardness (η), and electrophilicity (ω) were performed to understand the relationship between the structure and the energetic behavior of all the series. Then, in vitro analysis showed that compounds 27, 29–31, and 34 exhibited inhibitory activity against FXa and the corresponding half maximal inhibitory concentration (IC50) values were calculated. Next, a cell viability assay in HEK293 and HepG2 cell lines, and coagulation parameters (anti FXa, Prothrombin time (PT), activated Partial Thromboplastin Time (aPTT)) of the most active novel molecules were performed to determine the corresponding cytotoxicity and possible action on clotting pathways. The obtained results suggest that compounds 27 and 29 inhibited FXa targeting through coagulation factors in the intrinsic and extrinsic pathways. However, compound 34 may target coagulation FXa mainly by the extrinsic and common pathway. Interestingly, the most active compounds in relation to the inhibition activity against FXa and coagulation parameters did not show toxicity at the performed coagulation assay concentrations. Finally, docking studies confirmed the preferential binding mode of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives inside the active site of FXa.
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Franiak-Pietryga, Ida, Henryk Maciejewski, Barbara Ziemba, Dietmar Appelhans, Brigitte Voit, Malgorzata Misiewicz, Tadeusz Robak, Jacek Trelinski, Maria Bryszewska e Maciej Borowiec. "Blockage of Wnt/B-Catenin Signaling By Nanoparticles Reduces Survival and Proliferation of CLL Cells in Vitro". Blood 126, n. 23 (3 dicembre 2015): 3699. http://dx.doi.org/10.1182/blood.v126.23.3699.3699.
Abstract (sommario):
Abstract The Wnt pathway is critical for the proliferation and cell fate determination of many cell types, including B cells of chronic lymphocytic leukemia (CLL). Wnt proteins act on target cells by binding to the Frizzled (Fz)/low-density lipoprotein (LRP) complex at the cell membrane. In the hematopoietic system, Wnt/β-catenin signaling pathway has been shown to be important in the control of the survival, proliferation and differentiation of hematopoietic cells. Nanotechnology, a new and promising field, may be of use in medicine and the pharmaceutical industry. Dendrimers are nanoparticles of dendritic architecture. We have already proved the influence of PPI-G4-OS-M3 dendrimers in cultures in vitro on CLL cells apoptosis. CLL lymphocytes are characterized by the failure in the apoptosis pathway, but it is also proved that they manifest increased proliferation. Herein, the objective was to evaluate how MEC-1 cells survival and proliferation in vitro is affected by blockage of Wnt pathway by PPI-G4-OS-M3 dendrimer comparing to FA. Material and methods Dendrimer, in which approximately 35% of peripheral amino groups, was coated with maltotriose have been defined as PPI-G4-OS-M3 and was used in concentration of 8 mg/ml (the IC50 value for this dendrimer). 'OS' abbreviation stands for the open shell structure of carbohydrate-modified dendrimers. The molar mass of this PPI dendrimer was 31000 g/mol. Fludarabine (FA, Genzyme) in concentration of 1.6 µ M, based on previous studies, was used. MEC-1 (DSMZ no. ACC 497) was used as a homogenous cell line with del(17p)(11q). In cultures the percentage of apoptotic cells was verified using AnnV and PI by means of flow cytometer. Cells predominated in the early stage of apoptosis. A microarray gene expression (Agilent SurePrint Technologies) was performed. Samples were hybridized to a whole human genome microarray 8x60K. Arrays were scanned on Agilent DNA Microarray Scanner. Data were deposited at Gene Expression Omnibus (GEO) (accession number GSE68094). Analysis of differential expression of genes was done with the limma method (Smyth, G. K., 2004) as implemented in R/Bioconductor software. We used the FDR multiple testing adjustment. We declared as differentially expressed the genes with FDR-adjusted p-value <0.1, which means that 10% of genes declared as DE are expected to be false positives. Results PPI-G4-OS-M3 dendrimer depicts the ability to inhibit the proliferation increases with the rise in dendrimer concentration (MethoCultTM Assay, Stemcell Technology). Microarray data analysis pointed 7 out of 100 members of Wnt genes whose expression was significantly important. Details concerning genes description and expression are collected in the table 1. Table 1. Wnt genes expression in MEC-1 cells under influence of dendrimers and FA in 4-hour-cultures. PPI-G4-OS-M3 FA Probe set Gene symbol Gene full name logFC adj P value logFC adj P value P102117 WNT10A Wingless-type MMTV integration site family, member 10A -0.59 0.04 -0.56 0.03 P81103 SFRP2 Secreted frizzled-related protein 2 0.96 0.04 -0.59 0.07 P65518 DACT1 Dishevelled-binding antagonist of beta-catenin 1 0.66 0.05 0.81 0.03 P206359 CDH1 Cadherin 1 type 1 -0.71 0.05 -0.99 0.03 P119916 WNT6 Wingless-type MMTV integration site family, member 6 -1.93 0.1 -0.23 0.8 (NS) P1505 LRP5 Low density lipoprotein receptor-related protein 5 0.39 0.1 -0.28 0.1 P117029 LDLR Low density lipoprotein receptor 0.21 0.1 -0.49 0.03 Conclusion: Our results show significant changes and differences in some of Wnt/β-catenin pathway genes expression in CLL influenced by glycodendrimer and FA treatment. The downregulation in WNT10A, WNT6, SFRP2 expression results in β-catenin less phosphorylation and is subjected to proteosomal degradation. LRP5 and LDLR genes expression is also weak thus a reaction cascade is blocked and transcription process is suppressed. The loss of Wnt signals by dendrimers and FA treatment induces a reduction in the proliferation and survival of treatment resistant cell line MEC-1. To summarize, the PPI-G4-OS-M3 dendrimer demonstrated inhibition of proliferation beside higher cytotoxicity towards CLL cells. Its potency is similar to FA widely used in CLL therapy. Thus, dendrimers are a potential tool for CLL treatment. The study was partially supported by Grant No. DEC-2011/01/B/NZ5/01371from the National Science Centre, Poland Disclosures Robak: Novartis: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Research Funding.
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Bennour, Ines, Lucile Chatelain e Philippe Schollhammer. "Modulation of S‐Centered Reactivity: Impact of Terminal Ligands on Alkynyl Addition in [Fe2(µ‐S2)(CO)4L2] Complexes". European Journal of Inorganic Chemistry, 10 aprile 2024. http://dx.doi.org/10.1002/ejic.202400061.
Abstract (sommario):
The reactivity of complexes [Fe2(µ‐S2)(CO)4L2] (L = CO (1), PPh3 (2)), with lithium alkynylide reagents generated in situ, was investigated. The behavior of the S2‐bridge in these compounds depends on the substitution at the diiron core. The reaction with the hexacarbonyl derivative 1 leads to the formation of the 1,2‐dithiolene bridged complex [Fe2(µ‐SCH=C(R)S)(CO)6] (3R) while the molecule [Fe2(µ‐SH)(µ‐SC≡CR)(CO)4(PPh3)2] (5R), with an open butterfly structure, is isolated when reacting the disubstituted derivative 2. The disubstituted dithiolene complex [Fe2(µ‐SCH=C(Ph)S)(CO)4(PPh3)2] (4Ph) can only be obtained by substitution of carbonyls with PPh3 in 3R. In the presence of piperidine, 5R isomerizes into the 1,1’‐dithiolene bridged derivative 6Ph. The novel compounds 4‐6 were synthesized and characterized by IR and NMR spectroscopies. X‐ray crystallographic studies of the dithiolene complexes 3Ph‐4Ph allowed their structural analysis.
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Sojka, Peter A., Sayge M. Smith, Cheryl B. Greenacre, Kim Newkirk e Deidra J. H. Mountain. "Qualitative investigation of µ- and κ-opioid receptor distribution in the brains of budgerigars (Melopsittacus undulatus)". American Journal of Veterinary Research 83, n. 7 (1 luglio 2022). http://dx.doi.org/10.2460/ajvr.21.04.0052.
Abstract (sommario):
Abstract OBJECTIVE To perform a qualitative analysis of the distribution of µ- and κ-opioid receptor mRNA in the forebrain and midbrain of budgerigars (Melopsittacus undulatus). SAMPLE 8 brains of male budgerigars. PROCEDURES Custom-made RNA hybridization probes (RNAscope; Advanced Cell Diagnostics Inc) were used for fluorescent in situ hybridization (FISH) assays performed on selected fresh frozen prepared sections of brain tissue to identify µ- and κ-opioid receptor mRNA. RESULTS There was κ-opioid receptor mRNA present in the nucleus dorsomedialis posterior thalami, lateral striatum, mesopallium, tractus corticohabenularis et corticoseptalis, griseum et fibrosum, stratum griseum centrale, medial striatum, and area parahippocampalis. There was µ-opioid receptor mRNA present in the stratum griseum centrale, stratum opticum, dorsomedialis posterior thalami, area parahippocampalis, medial striatum, and nidopallium intermedium. CLINICAL RELEVANCE Consistent with previous studies in pigeons and domestic chicks, κ-opioid receptors were more abundant than µ-opioid receptors in the samples of the present study. The results of this study may also help explain the hyperexcitability or lack of response that can occur with administration of pure µ-opioid receptor agonists, but not κ-opioid receptor agonists. This study was not quantitative, so further research should endeavor to compare the various regions of the brain using FISH technology.
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Fusseis, Florian, Ian B. Butler, Damien Freitas, Alexis Cartwright-taylor, Stephen Elphick e Edward Andò. "4-dimensional in-situ/in-operando µ-CT imaging of geological processes at elevated temperatures and pressures using x-rays". e-Journal of Nondestructive Testing 27, n. 3 (marzo 2022). http://dx.doi.org/10.58286/26575.
Abstract (sommario):
Micro-scale processes have a profound effect on geoenergy applications, ore formation, underground waste storage, geomechanics, and seismic and volcanic hazards. Understanding these processes is thus important for most of our societal interests in the geosphere. However, important aspects of these processes are still poorly understood. This is because replicating the ambient conditions, in particular high pressures and temperatures, in experiments remains challenging. The means to document progress during experiments are limited and, as a consequence, the results of classical 'black-box experiments', equipped only with indirect monitoring systems, are often inconclusive. In-situ imaging of geological processes in experimental studies allows the direct observation and quantification of grain-scale developments that define the macro-scale behavior of geomaterials,with the limitation of small sample sizes. In-situ imaging thus provides a possibility to overcome some of the limitations of classical experiments. Conducting such in-situ µ-CT experiments at the relevant conditions while simultaneously acquiring image data of sufficient quality comes with its own challenges, and extracting relevant quantitative information from the resulting image data remains difficult. Here we present an overview over our activities in that field over the past decade. We outline an array of bespoke x-ray-transparent experimental environments that can recreate a wide range of geological conditions, and demonstrate how previously inaccessible information is gathered from the resulting data using advanced image analysis with the open-source python library SPAM. We demonstrate that the technique promises to significantly advance our understanding of processes shaping the geosphere.
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Shen, Wenai, Zhentao Long, Heng Wang e Hongping Zhu. "Power Analysis of Sdof Structures with Tuned Inerter Dampers Subjected to Earthquake Ground Motions". ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg, 2 dicembre 2020. http://dx.doi.org/10.1115/1.4049212.
Abstract (sommario):
Abstract Tuned inerter dampers (TID) have been demonstrated as efficient energy dissipation devices for seismic response control. However, its potential capability for energy harvesting remains largely unexplored. Here, we present a theoretical analysis of the power of a structure-TID system subjected to earthquake ground motions. The analytical solutions of the average damping power of the system are derived for considering white noise base excitations and the Kanai-Tajimi earthquake model, respectively. Comparisons of the numerical results of a Monte Carlo simulation and the theoretical predictions verify the accuracy of the analytical solutions. Besides, we uncover the influence of the TID parameters on the damping power and output power of the system. The optimal frequency ratio of the TID for maximizing its output power slightly differs from that for seismic response control, and the former varies with site conditions. In contrast, both the damping power and output power are not sensitive to the damping ratio of the TID. For short-period structures, a small inertance-to-mass ratio (µ) of the TID is beneficial to maximize its output power, while seismic response control requires a large µ. For long-period structures, the damping power and output power are not sensitive to the µ. Generally, a structure-TID system on a soft soil site absorbs more energy from a given earthquake and is capable of harvesting more energy than that on a hard soil site. This study may help develop new strategies for self-powered control and monitoring in civil structures.
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Moss, Laurence, Hemme Hijma, Mark Demitrack, Jessica Kim, Geert Jan Groeneveld, Monique van Velzen, Marieke Niesters, Erik Olofsen e Albert Dahan. "Neurocognitive effect of biased µ-opioid receptor agonist oliceridine, a utility function analysis and comparison with morphine". Anesthesiology, 1 settembre 2023. http://dx.doi.org/10.1097/aln.0000000000004758.
Abstract (sommario):
Background Oliceridine (Olinvyk®) is a μ-opioid receptor agonist that in contrast to conventional opioids preferentially engages the G-protein-coupled signaling pathway. We determined the utility function of oliceridine versus morphine based on neurocognitive tests and cold pressor test. Methods The study had a randomized, double-blind, placebo-controlled, partial block 3-way crossover design. Experiments were performed in 20 male and female volunteers. Subjects received intravenous oliceridine (1 or 3 mg; cohorts of 10 subjects/dose), morphine (5 or 10 mg; cohorts of 10 subjects/dose) or placebo on three separate occasions. Prior to and following dosing, neurocognitive tests, cold pressor test and plasma drug concentrations were obtained at regular intervals. Population pharmacokinetic-pharmacodynamic analyses served as basis for construction of a utility function, which is an objective function of probability of benefit minus probability of harm. Antinociception served as measure of benefit, slowing of saccadic peak velocity and increased body sway as measures of neurocognitive harm. Results The oliceridine and morphine C50’s, i.e. the effect-site concentrations causing 50% effect, were: antinociception 13±2 and 23±7 ng/mL, saccadic peak velocity 90±14 and 54±15 ng/mL, and body sway 10±2 and 5.6±0.8 ng/mL, respectively. The ratio oliceridine/morphine of the therapeutic indices, C50(benefit)/C50(harm), were 0.34 (95% CI 0.17-0.7; p<0.01) for saccadic peak velocity and 0.33 (0.16-0.50; p<0.01) for body sway. The oliceridine utility was positive across the effect-site concentration 5-77 ng/mL, indicative of a greater probability of benefit than harm. The morphine utility was not significantly different from zero from 0-100 ng/mL. Over the concentration range 15-50 ng/mL the oliceridine utility was superior to that of morphine (p < 0.01). Similar observations were made for body sway. Conclusions These data indicate that over the clinical concentration range, oliceridine is an analgesic with a favorable safety profile over morphine when considering analgesia and neurocognitive function.
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Gutiérrez-Rodríguez, Mario, Darío Bernal-Casasola, José Juan Díaz Rodríguez, José Manuel Vargas Girón e Tarik Moujoud. "The Urban Biography of a Mauritanian City: Microstratigraphic Analysis of the Eastern Quarter of Tamuda (Morocco)". African Archaeological Review, 30 dicembre 2022. http://dx.doi.org/10.1007/s10437-022-09506-5.
Abstract (sommario):
AbstractThe lack of vertical stratigraphic sondages and open area excavations constitutes a challenge to understanding Mauritanian urbanism. This makes the characterization of the spatio-temporal evolution of Mauritanian towns a difficult task. Systematic excavations carried out in Tamuda by several research teams in the twentieth century provided vertical and horizontal views of Mauritanian urbanism. Our study offers, for the first time, a high-resolution geoarchaeological analysis of Tamuda’s urban sequence (third through first century BC). The microfacies analysis, by means of micromorphology and µ-XRF of Spaces E18 and E20 of the Eastern Quarter revealed a complex interaction of deposits and site formation processes that resulted from changes in everyday urban life. In this respect, the overlap of different construction phases and the alternation of episodes of active use and abandonment is highly significant. This study examines the functional characterization of urban spaces, including the identification of midden activities, a roasting pit, and a milling site (possibly) linked to fish flour production. These activities leave traces on beaten floors and occupation surfaces, and several features indicate abandonment periods between short-term occupations. The result is a complex urban biography of this Mauritanian town, in which human occupation was not constant over time.
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Borkenstein, A. F., E. M. Borkenstein e R. Schmid. "Analysis of a novel hydrophobic acrylic enhanced monofocal intraocular lens compared to its standard monofocal type on the optical bench". BMC Ophthalmology 22, n. 1 (3 settembre 2022). http://dx.doi.org/10.1186/s12886-022-02584-8.
Abstract (sommario):
Abstract Introduction The aim of this laboratory study is to objectively analyze the new hydrophobic, acrylic, enhanced monofocal intraocular lens Acunex Quantum (AN6Q) and compare it with the monofocal platform Acunex AN6. Methods Two IOL models were analyzed (Acunex Quantum AN6Q and Acunex AN6, Teleon Surgical, Spankeren, Netherlands), each having the same refractive power of + 22.0 D, on the optical bench with the OptiSpheric IOL PRO 2. The measurements followed the guidelines of the International Standard Organization with following parameters: ISO 2 cornea (+ 0,28 µ), ISO 11979/2, lens placement in situ in NaCl with 35° temperature, 546 nm and selection of different aperture sizes (3.0 mm vs 4.5 mm). The aberrations of each IOL were evaluated by the WaveMaster IOL 2, a high-resolution Shack-Hartmann sensor in reverse projection setup. An in-situ model eye was used according to ISO 11979 in NaCl (n = 1.337) with 546 nm, mask width 4.51. Zernike polynomials up to 10th order were determined by means of the measured wavefront that describe the optical properties of the IOL. Results Through frequency modulation transfer function (mean) at 50 lp/mm (AN6Q/AN6 centered) was 0.687/0.731 (3.0 mm aperture) and 0.400/0.509 (4.5 mm aperture). The SR (mean) was 0.592/0.809 (3.0 mm) and 0.332/0.372 (4.5 mm). The MTF (mean) at 50 lp/mm (AN6Q/AN6 decentered by 1 mm) was 0.413/0.478 (3.0 mm) and 0.257/0.229 (4.5 mm). The SR (mean) was 0.393/0.404 (3.0 mm) and 0.183/0.212 (4.5 mm). The MTF (mean) at 50 lp/mm (AN6Q/AN6 tilted by 5°) was 0.508/0.710 (3.0 mm) and 0.337/0.513 (4.5 mm). The SR (mean) was 0.508/0.760 (3.0 mm) and 0.235/0.2372 (4.5 mm). AN6Q showed MTF peak of 0.55 with an enlarged depth of power of about 2.5 D and two cusps in the MTF curve. The spherical aberration Z 4–0 was about -0.21 µm and the secondary spherical aberration Z 6–0 was about 0.16 µm. No other relevant aberration showed up. Conclusion The new, enhanced monofocal AN6Q provides an extended range of focus with only slight decrease in contrast quality. Both types of the hydrophobic, acrylic Acunex IOL platform have its particular advantages in clinical settings and therefore its importance, respectively.
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Al-Garawi, Zahraa S., Ahmad H. Ismail, Duaa H. Hillo, Füreya Elif Öztürkkan, Hacali Necefoğlu, Gehad G. Mohamed e Abanoub Mosaad Abdallah. "Experimental and density functional theory studies on some metal oxides and the derived nanoclusters: a comparative effects on human ferritin". Discover Nano 19, n. 1 (15 gennaio 2024). http://dx.doi.org/10.1186/s11671-023-03922-5.
Abstract (sommario):
AbstractA comprehensive investigation into the green synthesis of metal oxide nanoparticles (NPs) has garnered significant attention due to its commendable reliability, sustainability, and environmentally friendly attributes. Green synthesis methods play a crucial role in mitigating the adverse effects associated with conventional approaches employed for nanostructure preparation. This research endeavors to examine the impact of ginger plant extract-assisted green synthesis of metal oxides NPs on the serum ferritin levels of anemic diabetic patients in vitro, focusing specifically on α-Fe2O3 and ZnO NPs. Sixty diabetic volunteers with anemia (35–50 years) and thirty healthy volunteers were enrolled as controls. The assessment was conducted using the VIDAS Ferritin (FER) assay. Photoluminescence (PL) spectroscopy measurements were performed to elucidate the intrinsic and extrinsic transitions of these NPs, affirming the successful formation of α-structured iron oxide. Density functional theory (DFT) calculations were carried out at the B3LYP/6-311++G(d,2p) level of theory to investigate the geometry optimization and molecular electrostatic potential maps of the NPs. Furthermore, TD-DFT calculations were employed to explore their frontier molecular orbitals and various quantum chemical parameters. The binding affinity and interaction types of ZnO and α-Fe2O3 NPs to the active site of the human H-Chain Ferritin (PDB ID: 2FHA) target were determined with the help of molecular docking. Results unveiled the crystalline structure of ZnO and the α-structure of α-Fe2O3. Analysis of the frontier molecular orbitals and dipole moment values demonstrated that ZnO (total dipole moment (D) = 5.80 µ) exhibited superior chemical reactivity, biological activity, and stronger molecular interactions with diverse force fields compared to α-Fe2O3 (D = 2.65 µ). Molecular docking of the metal oxides NPs with human H-chain ferritin provided evidence of robust hydrogen bond interactions and metal-acceptor bonds between the metal oxides and the target protein. This finding could have a great impact on using metal oxides NPs-ferritin as a therapeutic protein, however, further studies on their toxicity are required. Graphical abstract
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Rashid, Iliyas, Melina Campos, Travis Collier, Marc Crepeau, Allison Weakley, Hans Gripkey, Yoosook Lee, Hanno Schmidt e Gregory C. Lanzaro. "Spontaneous mutation rate estimates for the principal malaria vectors Anopheles coluzzii and Anopheles stephensi". Scientific Reports 12, n. 1 (7 gennaio 2022). http://dx.doi.org/10.1038/s41598-021-03943-z.
Abstract (sommario):
AbstractUsing high-depth whole genome sequencing of F0 mating pairs and multiple individual F1 offspring, we estimated the nuclear mutation rate per generation in the malaria vectors Anopheles coluzzii and Anopheles stephensi by detecting de novo genetic mutations. A purpose-built computer program was employed to filter actual mutations from a deep background of superficially similar artifacts resulting from read misalignment. Performance of filtering parameters was determined using software-simulated mutations, and the resulting estimate of false negative rate was used to correct final mutation rate estimates. Spontaneous mutation rates by base substitution were estimated at 1.00 × 10−9 (95% confidence interval, 2.06 × 10−10—2.91 × 10−9) and 1.36 × 10−9 (95% confidence interval, 4.42 × 10−10—3.18 × 10−9) per site per generation in A. coluzzii and A. stephensi respectively. Although similar studies have been performed on other insect species including dipterans, this is the first study to empirically measure mutation rates in the important genus Anopheles, and thus provides an estimate of µ that will be of utility for comparative evolutionary genomics, as well as for population genetic analysis of malaria vector mosquito species.
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Chandran, Amoolya, Goldamol S. Pallam, Swathy S e K. Girish Kumar. "Recent Advances and Perceptions in the Electrochemical Sensing of Plant Protecting Agrochemical Organic Pollutants". Current Analytical Chemistry 18 (21 aprile 2022). http://dx.doi.org/10.2174/1573411018666220421122707.
Abstract (sommario):
Background: Plant protecting agrochemicals have significant contribution to enhance the crop production to meet the food requirement of upsurging global population. Meanwhile their long persistence, rampant aerial transit, bioaccumulation and resistance to degradation ascribe it as a catastrophic toxicant. Therefore the availability of early-warning and sensing systems for these toxic compounds especially organic toxicants, is inevitable due to uncontrollable environmental pollution by anthropogenic activities. Method: The literature and published papers available for electrochemical sensing of plant protecting synthetic agrochemicals namely insecticides, herbicides and acaricides were collected, critically evaluated and reviewed. Result: Compared to the conventional methods of quantification of organic pollutants, electrochemical sensors offer prospects of real time analysis, miniaturization, rapid response and on-site monitoring. Considering the diverse electrochemical sensing strategies designed for certain agronomically relevant plant protecting synthetic organic pollutants comes under organophosphate insecticides, carbamates, organochlorine insecticides, acaricides and herbicides, most widely reported sensors include voltammetric, amperometric and impedimetric sensors. Moreover microfluidic devices are also employed very recently for onsite detection and real-time monitoring. organic pollutants, electrochemical sensors offer prospects of real time analysis, miniaturization, rapid response and on-site monitoring. Considering the diverse electrochemical sensing strategies designed for certain agronomically relevant plant protecting synthetic organic pollutants comes under organophosphate insecticides, carbamates, organochlorine insecticides, acaricides and herbicides, most widely reported sensors include voltammetric, amperometric and impedimetric sensors. Moreover microfluidic devices are also employed very recently for onsite detection and real-time monitoring. Conclusion: This review describes state-of-the-art in electrochemical sensors specifically voltammetric, impedimetric, amperometric and potentiometric sensing strategies for the quantification of agrochemical organic pollutants.The emergence of microfluidic paper-based analytical devices (µ-PAD) by utilizing microfabrication technology and different electrode modifiers like metal-carbon nanocomposites, biorecognition elements could provide easy and sensitive detection of pollutants.
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Simons, Pieter, Rutger van der Schrier, Maarten van Lemmen, Simone Jansen, Kiki WK Kuijpers, Monique van Velzen, Elise Sarton et al. "Respiratory effects of biased-ligand oliceridine in older volunteers: a pharmacokinetic-pharmacodynamic comparison with morphine". Anesthesiology, 20 dicembre 2022. http://dx.doi.org/10.1097/aln.0000000000004473.
Abstract (sommario):
Background Oliceridine is a G protein-biased µ-opioid, a drug class that is associated with less respiratory depression than non-biased opioids, such as morphine. We quantified the respiratory effects of oliceridine and morphine in elderly volunteers. We hypothesized that these opioids differ in their pharmacodynamic behavior, measured as effect on ventilation at an extrapolated end-tidal PCO2 at 55 mmHg, V̇E55. Methods This four-arm double-blind, randomized, crossover study examined the respiratory effects of intravenous oliceridine 0.5 or 2 mg and morphine 2 or 8 ;mg in 18 healthy male and female volunteers, aged 55-89 years, on four separate occasions. Participants’ CYP2D6 genotypes were determined, hypercapnic ventilatory responses were obtained and arterial blood samples collected before and for 6-h following treatment. A population pharmacokinetic-pharmacodynamic analysis was performed on V̇E55, the primary endpoint; values reported are median ± standard error of the estimate. Results Oliceridine at low-dose was devoid of significant respiratory effects. High-dose oliceridine and both morphine doses caused a rapid onset of respiratory depression with peak effects occurring at 0.5 to 1-h after opioid dosing. Following peak effect, compared to morphine, respiratory depression induced by oliceridine returned faster to baseline. The effect-site concentrations causing a 50% depression of V̇E55 were 29.9 ;± ;3.5 ;ng/mL (oliceridine) and 21.5 ;± ;4.6 ;ng/mL (morphine), the blood effect-site equilibration half-lives differed by a factor of 5: oliceridine 44.3 ;± ;6.1 ;min and morphine 214 ;± ;27 ;min. Three poor CYP2D6 oliceridine metabolizers exhibited a significant difference in oliceridine clearance by about 50%, causing higher oliceridine plasma concentrations following both low- and high-dose oliceridine, compared to the other participants. Conclusions Oliceridine and morphine differ in their respiratory pharmacodynamics with a more rapid onset and offset of respiratory depression for oliceridine and smaller magnitude of respiratory depression over time.
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Radhakrishnan, Janani, Manjula Muthuraj, Gnana Santi Phani Deepika Gandham, Swaminathan Sethuraman e Anuradha Subramanian. "Nanohydroxyapatite-Protein Interface in Composite Sintered Scaffold Influences Bone Regeneration in Rabbit Ulnar Segmental Defect". Journal of Materials Science: Materials in Medicine 33, n. 4 (aprile 2022). http://dx.doi.org/10.1007/s10856-022-06657-4.
Abstract (sommario):
AbstractThe healing physiology of bone repair and remodeling that occurs after normal fracture is well orchestrated. However, it fails in complex clinical conditions and hence requires augmentation by grafts. In this study, composite nanohydroxyapatite (nHA), poly(hydroxybutyrate) (PHB) and poly(ɛ-caprolactone) (PCL) constituted microspheres sintered three-dimensional scaffold were evaluated in rabbit ulnar segmental defect. A composite scaffold using PHB-PCL-nHA microspheres was developed with protein interface by solvent/non-solvent sintering to provide multiple cues such as biocomposition, cancellous bone equivalent meso-micro multi-scale porosity, and compressive strength. In vitro DNA quantification and alkaline phosphatase (ALP) assays revealed that the protein interfaced composite scaffolds supported osteoblast proliferation and mineralization significantly higher than scaffolds without protein and TCPS (p < 0.05). Scanning electron micrographs of osteoblasts cultured scaffolds demonstrated cell-matrix interaction, cell spreading, colonization and filopodial extension across the porous voids. Cylindrical scaffolds (5 × 10 mm) were implanted following segmental defect (10 mm) in rabbit ulnar bone and compared with untreated control. Radiography (4, 8 and 12 weeks) and µ-computed tomography (12 weeks) analysis showed directional bone tissue formation by bridging defective site in both scaffolds with and without protein interface. Whereas, undesired sclerotic-like tissue formation was observed in control groups from 8 weeks. Histology by hot Stevenel’s blue and van Gieson’s picrofuchsin staining has confirmed enhanced bone maturation in scaffold groups while presence of osteoids was observed in control after 12 weeks. Thus, the developed composite matrices exhibits osteoinductive, osteoconductive properties and demonstrates its bone regenerative potential owing to its compositional, micro & macro structural and mechanical properties.