Gold Silver Research Articles

Computational identification of PDL1 inhibitors and their cytotoxic effects with silver and gold nanoparticles

Immunotherapy is a promising treatment for cancer that aims to boost the immune system’s response to cancer cells. This can be achieved by blocking Programmed cell death protein 1/Programmed death-ligand 1 (PD1/PDL1), which activates T cells. In this work, the aim was to find high-affinity drugs against PDL1 using computational tools and conjugate nanoparticles with them. The cytotoxic activity of the nanoparticle conjugated drugs was then tested. The screening of 100,000 drugs from the ZINC database and FDA-approved drugs was done computationally. The physicochemical properties and toxicity of the drugs were analyzed using SwissADME and ProTox-II, respectively. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized using extracts of Catharanthus roseus flowers and Juglans regia shells, respectively. The characterization of AgNPs and AuNPs was performed using UV–Vis spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Their conjugation with the drugs Irinotecan, Imatinib, and Methotrexate was also confirmed using UV–Vis, FTIR, and Dynamic light scattering (DLS). The top screened drugs were ZINC1098661 and 3 FDA-approved drugs (Irinotecan, Imatinib, and Methotrexate). Docking studies revealed that Irinotecan had the highest binding affinity towards PDL1 when conjugated with silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs). The Irinotecan-PDL1 complex was confirmed as the most stable through molecular dynamics simulations. The result of the methylthiazol tetrazolium (MTT) assay showed that conjugated AgNPs and AuNPs with Irinotecan had a higher toxic effect on the A549 cancer cell line than AgNPs and AuNPs conjugated with Imatinib. This study provides a promising avenue for further investigation and development of nanoparticle-drug conjugates as a potential cancer immunotherapy strategy.

In-situ trace element and sulfur isotope compositions of Multi-Stage sulfides in the Buzhu orogenic gold (Antimony) Deposit, southern Tibet: Implications for the metallogenic process

The Buzhu gold (antimony) deposit, located within the gold-antimony polymetallic belt of southern Tibet in the Tethys Himalayan belt, is a recently discovered medium-sized gold polymetallic deposit. The orebody consists primarily of gold-bearing quartz sulfide veins. Currently, the metallogenic mechanism of the deposit remains largely unexplored. Utilizing results from the mineralogical observation of principal ore minerals, LA-ICP-MS trace element analysis, and in-situ sulfur isotope analysis of pyrite, investigations reconstruct the evolution process of pyrite-arsenopyrite and constrain the metallogenic process of the Buzhu gold (antimony) deposit. It has been discovered that the gold-bearing sulfides in the Buzhu gold (antimony) deposit are primarily pyrite and arsenopyrite. Pyrite can be categorized into six generations: framboidal pyrite Py0, dissolution cavity pyrite Py1a (some exhibiting oscillatory zoning), disseminated pyrite Py1b, euhedral pyrite Py2a, irregular pyrite Py2b, and Py3. Arsenopyrite, on the other hand, can be classified into three generations: early arsenopyrite Apy0, disseminated arsenopyrite Apy1, and euhedral Apy2. The analysis of δ34S in pyrite throughout the ore-forming process indicates sulfur derives from multiple sources, with Py0 indicative of a biological sulfur source. The evolutionary process of pyrite, supported by trace element analysis, suggests that the remaining pyrite derives from sedimentary fluid transformation, with sulfur primarily sourced from metamorphic sediments. Elemental spectrum analysis and BSE observations indicate that the Buzhu gold (antimony) deposit primarily undergoes two distinct stages of mineralization: the initial stage is the gold-antimony mineralization phase, during which antimony precipitates in the fissures of Py1a as stibnite, while gold is primarily found in Py1-Apy1 as invisible gold, with the highest gold content in Apy1 (28.20–60.13 ppm, average 40.51 ppm). The subsequent stage of mineralization is characterized by gold mineralization, with gold primarily residing in the internal fissures of Apy2 as micron silver gold ore. The evolution characteristics of gold-bearing sulphide and the solubility curve of Au indicate that gold mainly derives from gold-bearing unsaturated fluid, rather than from early framboidal pyrite Py0 (0.52–1.06 ppm, average 0.79 ppm). Only a minor fraction of gold (originating from early sediments) in Py0 was liberated and integrated into subsequent pyrites. The content of antimony in Py0 significantly reduces after dissolution, suggesting that antimony predominantly originates from Py0 (206–440 ppm, average 335 ppm). Throughout the genesis of the Buzhu gold (antimony) deposit, the gold constituent underwent a sequence of pre-enrichment, re-enrichment, liberation, and precipitation. The processes of coupled dissolution-reprecipitation (CDR) and boiling fostered the reactivation and reenrichment of gold. The recrystallization into cubic pyrite led to the expulsion of gold from the pyrite lattice, and fluid oxidation resulting from multistage fluid boiling, coupled with a decrease in sulfur fugacity, led to gold precipitation.

Antibacterial and Cytotoxicity characteristics of experimental epoxy -based endodontic sealer loaded with silver gold nanoparticles: in vitro study

BackgroundEnhancing the antibacterial capabilities of dental materials by adding nanoparticles has been the subject of some research. However, the potential toxic effect of this material on the vital tissues should be investigated to avoid additional damage to the tissue.ObjectiveThis study aimed to validate the long-term cytotoxic and antibacterial properties of an epoxy resin-based endodontic sealer (AH Plus) with and without loading with silver gold nanoparticles (Nano Care Plus Silver Gold®).Material and methodsThe tested groups were Nano Care Gold (group I), modified resin sealer (m AH Plus; group II) and AH Plus served as a control group (group III). Agar diffusion was used to measure the antibacterial activity against Enterococcus faecalis. Using the MTT test, cytotoxicity assessment was carried out in accordance with ISO-10993-5 guidelines to assess the cells’ viability as soon as possible and after two and four weeks. The t-test was used to statistically examine the data. The chosen significance threshold was P <0.05.ResultsAntibacterial results revealed that there was no difference in the diameter of the inhibition zones measured in all groups at 24 h. While in 48 and 72 h, the difference was statistically significant (p <0.05). In 48-h Nanogold was significantly higher than AH Plus when tested alone (p <0.05), however their mixture showed insignificant difference. After 72 h, the Nano gold was significantly higher than that of AH Plus & Nano gold mixture (p <0.05). Cytotoxicity result revealed there was a significant difference between tested groups at different intervals (p <0.001). For immediate measurements, values measured with the AH group were significantly higher than those of other groups (p <0.001). For the AH& nanogold group, there was no significant difference between values measured at different intervals (p = 0.578).ConclusionsSilver gold nanoparticles have acceptable antibacterial properties and low cytotoxicity to be used as canal pretreatment prior to the application of the sealer or even incorporated with AH Plus sealer.

Inkjet-Printed Localized Surface Plasmon Resonance Subpixel Gas Sensor Array for Enhanced Identification and Visualization of Gas Spatial Distributions from Multiple Odor Sources

The visualization of the spatial distributions of gases from various sources is essential to understanding the composition, localization, and behavior of these gases. In this study, an inkjet-printed localized surface plasmon resonance (LSPR) subpixel gas sensor array was developed to visualize the spatial distributions of gases and to differentiate between acetic acid, geraniol, pentadecane, and cis-jasmone. The sensor array, which integrates gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and fluorescent pigments, was positioned 3 cm above the gas source. Hyperspectral imaging was used to capture the LSPR spectra across the sensor array, and these spectra were then used to construct gas information matrices. Principal component analysis (PCA) enabled effective classification of the gases and localization of their sources based on observed spectral differences. Heat maps that visualized the gas concentrations were generated using the mean squared error (MSE) between the sensor responses and reference spectra. The array identified and visualized the four gas sources successfully, thus demonstrating its potential for gas localization and detection applications. The study highlights a straightforward, cost-effective approach to gas sensing and visualization, and in future work, we intend to refine the sensor fabrication process and enhance the detection of complex gas mixtures.

Rapid and highly sensitive detection of trace chromium and copper in tea infusion using laser-induced breakdown spectroscopy combined with electrospinning technology

Tea infusion, as one of the most popular beverages, is favored by people around the world. However, tea plants accumulate heavy metals from the soil during growth, which are gradually transferred to the leaves and subsequently decomposed into the tea infusion after soaking in hot water. Long-term consumption of tea infusion containing heavy metals may lead to severe health issues, such as liver dysfunction and cancer. Therefore, rapid, precise, and highly sensitive detection of heavy metals in tea infusion becomes crucial for human health. Traditional methods, such as atomic absorption spectroscopy (AAS), suffer from long detection cycles, high costs, and the risk of secondary pollution from chemical extraction reagents. Thus, this paper presents a method, using laser-induced breakdown spectroscopy combined with electrospinning technology (LIBS-ES), to detect trace amounts of Cr and Cu in tea infusion. The electrospun nanofiber membranes (ENM) were modified with gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), achieving ultra-sensitive detection of Cr and Cu. The experiment results show that the limits of detection for Cr and Cu are 5 μg/L and 10 μg/L, respectively. Moreover, this method was successfully applied to the detection of Cr and Cu in seven different types of tea infusion, achieving recovery rates of 99 %-106 % and 99 %-108 %, respectively. The method demonstrated good performance even under the interference of other ions at various concentrations, providing a reference for the rapid and highly sensitive detection of heavy metals in tea infusion.

Scalable incident detection via natural language processing and probabilistic language models

Post marketing safety surveillance depends in part on the ability to detect concerning clinical events at scale. Spontaneous reporting might be an effective component of safety surveillance, but it requires awareness and understanding among healthcare professionals to achieve its potential. Reliance on readily available structured data such as diagnostic codes risks under-coding and imprecision. Clinical textual data might bridge these gaps, and natural language processing (NLP) has been shown to aid in scalable phenotyping across healthcare records in multiple clinical domains. In this study, we developed and validated a novel incident phenotyping approach using unstructured clinical textual data agnostic to Electronic Health Record (EHR) and note type. It’s based on a published, validated approach (PheRe) used to ascertain social determinants of health and suicidality across entire healthcare records. To demonstrate generalizability, we validated this approach on two separate phenotypes that share common challenges with respect to accurate ascertainment: (1) suicide attempt; (2) sleep-related behaviors. With samples of 89,428 records and 35,863 records for suicide attempt and sleep-related behaviors, respectively, we conducted silver standard (diagnostic coding) and gold standard (manual chart review) validation. We showed Area Under the Precision-Recall Curve of ~ 0.77 (95% CI 0.75–0.78) for suicide attempt and AUPR ~ 0.31 (95% CI 0.28–0.34) for sleep-related behaviors. We also evaluated performance by coded race and demonstrated differences in performance by race differed across phenotypes. Scalable phenotyping models, like most healthcare AI, require algorithmovigilance and debiasing prior to implementation.

Nanoclay composites in electrochemical sensors

Nanoclays are layered structures in the nanoscale range with widespread application due to their unique properties such as swelling, cation exchange capacity, and ease of functionalisation using metals, metal oxides, and organic compounds such as carbon paste, polymers, and other biomolecules that form nanoclay composites. Nanoclay functionalisation with silver (Ag), zinc oxide (ZnO), and bimetallic silver–gold (Ag–Au) using hydrophilic and hydrophobic clays is here evaluated and discussed. The composites’ synthesis and morphological, crystallinity, and electroactive properties in comparison with pure nanoclay are also assessed. The layered structure and crystallinity of all these nanoclay composites were slightly changed. The clumped layered structures on the surface of the nanocomposites had dispersed white spots that indicated possible surface modification. The nano-films of the composites’ electroactivity were comparatively high, as seen from the increase in current in the cyclic voltammetry characterisation voltammograms and the differential pulse voltammograms of the pharmaceutical detection. Efavirenz, nevirapine, and zidovudine detection was improved by modification of the nanocomposite with human serum albumin (HSA), as shown by the higher current, thus indicating improved conductivity of the composites compared to the pure nanoclays. Applying HAS-modified nanocomposites in the analysis of efavirenz, nevirapine, and zidovudine on a glassy carbon electrode (GCE) showed good linearity and acceptable detection limits comparable to those of previous studies. Therefore, it has potential for application in pharmaceutical quality control and environmental monitoring.

Bimetallic Au-Ag Reduced Graphene Oxide Nanostructures for Enhanced Detection of Dengue Virus E Protein

The development of highly sensitive and specific diagnostic tools for early-stage detection of dengue virus (DENV) is critical for effective outbreak management, particularly in resource-limited settings. In this study, we report a novel electrochemical immunosensor based on bimetallic gold silver (Au-Ag) nanoparticles integrated with reduced graphene oxide (rGO) for the detection of dengue virus envelope (E) protein. The Au-Ag bimetallic nanostructures exhibit superior electron transfer kinetics and enhanced electrocatalytic activity, while rGO serves as an excellent platform due to its large surface area and high conductivity. This synergistic combination improves antigen-antibody interactions and significantly boosts sensor performance. The immunosensor demonstrated a broad linear detection range of 100 ag ml−1 to 10 ng ml−1, with a high correlation coefficient (R2 = 0.98519). It achieved an ultra-low limit of detection (LOD) of 4.959 ag ml−1 for DENV E protein, outperforming existing detection methods. These findings highlight the potential of the Au-Ag- rGO-based immunosensor as a promising tool for point-of-care diagnosis, enabling rapid and cost-effective disease management and control.

Non-invasive method to measure bulk electrical resistivity of spruce wood – influence of moisture content and anatomical direction

ABSTRACT The correlation between electrical resistance and moisture content (MC) of wood has been studied for many years and is the basis for an important method for determining wood MC in practice. This study presents a non-invasive set-up using plate electrodes with a guard ring covered with silver foam and gold leaves to measure the direct-current (DC) electrical resistivity of spruce wood. The design ensures good electrical contact at a pressure of 0.68 MPa, without impairing the wood surface. Measurements were conducted across various moisture contents up to the fiber saturation point (FSP) for the three anatomical directions at a temperature of 21°C. The regression parameters between electrical resistivity and moisture content were determined with high coefficients of determination (R² = 0,97–0.98). The effect of MC on the electrical resistance was significantly more pronounced in the radial direction, and the electrical resistance in the axial direction was lower than in the radial and tangential direction. Those findings support the basic understanding of the electrical properties of spruce wood and provide a basis for non-invasive volume resistivity measurements of wood.

Nanoscale dosimetry for a radioisotope-labeled metal nanoparticle using MCNP6.2 and Geant4.

Metal nanoparticles (MNPs) labeled with radioisotopes (RIs) are utilized as radio-enhancers due to their ability to amplify the radiation dose in their immediate vicinity. A thorough understanding of nanoscale dosimetry around MNPs enables their effective application in radiotherapy. However, nanoscale dosimetry around MNPs still requires further investigation. This study aims to provide insight into the radio-enhancement effects of MNPs by elucidating nanoscale dosimetry surrounding MNPs labeled with Auger-emitting RIs. We particularly focus on distinguishing the respective dose contributions of photons and electrons emitted by Auger-emitting RIs in the context of dose enhancement. A 50nm diameter NP of silver (Ag) core and gold (Au) shell (Ag@Au NP) was assumed to emit mono-energetic electrons and photons (3, 5, 10, 20, and 30keV), or the energy spectrum corresponding to one of three Auger-emitting RIs (103Pd, 125I, and 131Cs) from the Ag core. Nanoscale radial dose distributions around a single radioactive Ag@Au NP were evaluated in spherical shells of water. Monte Carlo simulations were conducted using single-event and track structure transport methods implemented in MCNP6.2 and Geant4-DNA-Au physics, respectively. To evaluate the extent of radio-enhancement by the Ag@Au NP, two scenarios were considered: Ag@Au NPs (Au shell included) and Ag@water NPs (Au shell replaced by water). The radial doses of 10, 20, and 30keV electrons estimated by both codes were comparable. However, the radial doses of 3 and 5keV electrons by MCNP6.2 were much larger near the NP surface than those by Geant4. There was a dose enhancement of a few % to tens % by the Au shell in the region of the NP surface to 10µm, depending on the electron energy. The radial doses of photons with the Au shell were higher up to their secondary electron ranges than those without the Au shell. The maximum dose enhancement factor of photons occurred at 20keV and was 63.4 by MCNP6.2 and 50.5 by Geant4. The overall radial doses of electrons were 1-2 orders of magnitude larger than those of photons. As a result, in cases of RIs emitting both electrons and photons, the radial doses up to electron ranges were dominantly governed by electrons. The dose enhancement estimated by both codes for the RIs ranged from a few % except in the immediate vicinity of the NP surface. Given the dominant contribution of electrons to radial doses of MNP labeled with Auger-emitting RIs, physical dose enhancement expected by interactions with photons was hindered. Since there are no available RIs emitting exclusively photons, achieving enhanced physical doses within a cell through a combination of MNPs and RIs appears currently unattainable. The radial doses of photons near the NP surface exhibited considerable discrepancies between the codes, primarily attributed to low-energy electrons. The difference may arise from higher cross-sections of Au inelastic scattering in Geant4-DNA-Au compared to MCNP6.2.

Synthesis of a Gold–Silver Alloy Nanocluster within a Ring‐Shaped Polyoxometalate and Its Photocatalytic Property

AbstractAlloying is an effective method for modulating metal nanoclusters to enrich their structural diversity and physicochemical properties. Recent investigations have demonstrated that polyoxometalates (POMs) can act as effective multidentate ligands for silver (Ag) nanoclusters to endow them with synergistic properties, reactivity, catalytic properties, and stability. However, the application of POMs as ligands has been confined predominantly to monometallic nanoclusters. Herein, we report a synthetic method for fabricating surface‐exposed gold (Au)−Ag alloy nanoclusters within a ring‐shaped POM ([P8W48O184]40−). Reacting an Ag nanocluster stabilized by the ring‐shaped POM with Au ions (Au+) was found to substitute several Ag atoms at the core of the nanocluster with Au atoms. The resultant {Au8Ag26} alloy nanocluster demonstrated superior photocatalytic activity and stability compared to the pristine Ag nanocluster in the aerobic oxidation of α‐terpinene under visible‐light irradiation. These findings provide fundamental insights into the formation and catalytic properties of POM‐stabilized alloy nanoclusters and advance exploration into the synthesis and applications of diverse metal nanoclusters.

Drastic Enhancement of Hydrogen Production from Water in Gold–Silver Sulfide Hybrid Quantum Dot-Sensitized Photoelectrochemical Cell through Plasmon–Plasmon–Exciton Coupling

Drastic Enhancement of Hydrogen Production from Water in Gold–Silver Sulfide Hybrid Quantum Dot-Sensitized Photoelectrochemical Cell through Plasmon–Plasmon–Exciton Coupling

Six-channel colorimetric sensing of metal ions and advanced molecular information security based on fish scale-derived carbon–gold–silver nanocomposites

Due to its high flexibility and expansibility, nanomaterials-based systems have been constructed and applied from sensing, and medicine to molecular information technology. However, the current challenges include tedious and harsh nanomaterials preparation, the need for a wider range of response channels, new information paradigms, higher information density and length. Herein, fish-scale derived carbon nanomaterials (FSCN) were used as reducing and stabilizing agents for direct, green, and facile synthesis of carbon-bimetallic nanocomposites and applications in six-channel colorimetric sensing of Hg2+, and multi-combination and multi-round information encoding and protection for long text. First, the reaction sequence of three precursors (FSCN, Au3+, Ag+) was optimized to prepare FSCN–Au–Ag nanocomposites with double plasmonic absorption peaks of Au/Ag nanoparticles (NPs). The addition of Hg2+ causes the aggregation of nanoparticles and the formation of Ag/Hg amalgam or Au/Hg amalgam, FSCN–Au–Ag NPs were capable of multi-channel sensing (color, absorbance, and peak shift) of Hg2+. Especially, the detection limit of Hg2+ was 8.9 nM based on absorption response in wide wavelength range (456–546 nm), which was at least 6 times more sensitive than that at single wavelength. Moreover, different long text information can be encrypted and hidden in six-channel selective responses of FSCN–Au–Ag NPs-based colorimetric sensing system. By setting the threshold, these selective responses can be abstracted as a series of binary strings and then divided into shorter strings. Utilizing multi-combination and multi-round information coding, these short binary strings can be decrypted and merged into various long text content. This research promotes preparation and multi-purpose application of carbon-bimetallic nanomaterials, which provides new way to improve the sensing sensitivity of nanosystems and also offers new direction for molecular digitization.

Influence of metal and metal oxide nanoparticles on growth and total phenolic content accumulation of Anoectochilus roxburghii cultured in vitro

The application of metal nanoparticles in agriculture and related fields, especially in plant cell tissue culture has increased interest in recent years due to its potential benefits. This study used gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), copper nanoparticles (CuNPs) and magnetite nanoparticles (Fe3O4NPs) to evaluate their effect on the growth and total phenolic content (TPC) of Anoectochilus roxburghii. The results showed that Fe3O4 NPs were the most positively influenced metal nanoparticles in increasing biomass and TPC of A. roxburghii among metal nanoparticles tested. After 8 weeks of culture, the dry weight (DW) and TPC of the plants cultured on the medium containing 5 ppm Fe3O4NPs were 39.07 mg and 13.0 mg gallic acid respectively per g of dry weight (mg GAE/g DW). Meanwhile, on the medium without Fe3O4NPs, they were 30.47 mg and 6.71 mg GAE/g DW respectively. This study proposed an effective approach to improve the growth and accumulation of TPC in A. roxburghii. Moreover, it suggests the potential application of metal nanoparticles in plant tissue culture and the production of bioactive compounds.

Exploring the Biomedical Frontiers of Plant-Derived Nanoparticles: Synthesis and Biological Reactions.

As contemporary technology advances, scientists are striving to identify new approaches to managing several diseases. Compared to the more popular physiochemical synthesis, the plant-derived combination of metallic nanoparticles using plant secondary metabolites as a precursor has a number of benefits, including low expenses, low energy consumption, biocompatibility, and medicinal usefulness. This study intends to explore the impacts of using plant-derived synthetic materials including metallic nanoparticles (NPs), emphasizing the benefits of their broad use in next-generation treatments for cancer, diabetes, Alzheimer's, and vector diseases. This comprehensive analysis investigates the potential of plant-derived remedies for diseases and looks at cutting-edge nanoformulation techniques aimed at addressing the function of the nanoparticles that accompany these organic substances. The purpose of the current review is to determine how plant extracts contribute to the synthesis of Silver nanoparticles (AgNPs), Gold nanoparticles (GtNPs), and platinum nanoparticles (PtNPs). It provides an overview of the many phytocompounds and their functions in biomedicine, including antibacterial, antioxidant, anticancer, and anti-inflammatory properties. Furthermore, this study placed a special focus on a range of applications, including drug delivery systems, diagnostics and therapy, the present benefits of nanoparticles (NPs), their biomedical uses in medical technology, and their toxicities.

Development of Electrochemical and Colorimetric Biosensors for Detection of Dopamine

Neurotransmitters are essential chemical messengers required for proper brain function, and any changes in their concentrations can lead to neuronal diseases. Therefore, sensitive and selective detection is crucial. This study presents a fast and simple colorimetric method for dopamine detection using three reagent solutions: AgNP and MPA, Ag/Au nanocomposite, and mercaptophenylacetic acid. TEM images showed a narrow distribution of Ag and Au nanoparticles with average sizes of 20 nm and 13 nm, respectively, with gold nanoparticles bound to the edges of silver nanoparticles. A paper-based biosensor was created using manual wax printing for the colorimetric detection of dopamine. Visual detection onsite showed color changes with both the silver nanoparticles and mercaptophenylacetic acid mixture and the silver–gold nanoparticle composite. Electrochemical detection using a glassy carbon electrode modified with 8 mM mercaptophenylacetic acid demonstrated high selectivity and sensitivity towards dopamine, with a peak in the range of 0.7–0.9 V. Interferences were minimized, ensuring high sensitivity and selective detection of dopamine.

Mineralogy and Hydrothermal Fluids Characteristics of the Mekarbakti Low Sulfidation Epithermal Gold Prospect at Garut Regency, West Java, Indonesia

Abstract Mekarbakti prospect is situated in the western sector of Java Island which tectonically lies within the W-E trending Sunda-Banda magmatic arc. This arc hosts numerous prospects for ore mineralization with various types of mineral deposits, one of which is epithermal that found in the study area. The Mekarbakti prospect is located close to the Arinem prospect, about 8 km to the east, which is confirmed as a low sulfidation epithermal deposit type. Arinem is proven to be economical to mine, thus it becomes interesting to conduct study on the Mekarbakti prospect, to elucidate its mineralization model. This paper is dealing with the characteristics of hydrothermal alteration using petrographic and X-Ray Diffraction (XRD) to identify the alteration minerals, using ore microscopy analysis to identify the type of ore minerals, and fluid inclusion to reveal the hydrothermal fluid characteristics. The geological condition of the study area is composed of andesite lava, andesite breccia, tuff, lapilli, and andesite intrusion. The distribution of silicification alteration is controlled by geological structures with an NW-SE pattern, while argillic and propylitic alterations tend to have a gradient trend towards silicification alteration. Propylitic alteration is characterized by chlorite+illite+smectite±epidote. Argilic alteration is marked by the presence of clay minerals such as kaolinite+illite+smectite+quartz. Silicification alteration typified by quartz+kaolinite+diaspore+illite. Ore mineralization in the study area is associated with massive, brecciated, comb, cockade and, stockwork vein textures. Ore and metalliferous minerals are found as pyrite, hematite, goethite, chalcopyrite, sphalerite, galena, pyrrhotite, covellite, chalcocite, acanthite, native gold, and native silver. Generally, the mean homogenization temperature in the research area ranged from 248.05 – 266.12 °C, with salinity ranged from 1.01 – 1.68 wt.% NaCl eq. The epithermal deposit in the study area is classified as deep low sulfidation epithermal deposit specifically in transition between base metal and precious metal interval.

Anti-Biofouling Effect of Nanoporous Gold Electrode on Nonspecific Signal Reduction for Electrochemical Biosensors

Noise signals based on nonspecific adsorptions of interfering species (biofouling) should be reduced in electrochemical biosensors to increase the signal-to-noise ratio. Here, we demonstrate the effect of the structure of nanoporous gold (np-Au) electrodes on anti-biofouling in electrochemical biosensors. A np-Au electrode is fabricated by a gold–silver alloy corrosion process. The pore size of the np-Au electrode is controlled within 10–50 nm by adjusting the time of corrosion of silver. The np-Au electrode, the pore size of which is slightly larger (15–30 nm) than the size of proteins such as human serum albumin (HSA), notably shows the suppression of the nonspecific adsorption of HSA on its surface in cyclic voltammetry (CV), resulting in the anti-biofouling effect. In particular, the peak current in CV with the np-Au electrode is maintained at about 80% even for a long-term incubation of 60 min after the addition of human serum and plasma as well as HSA, whereas that with the bare gold electrode is reduced to about 25%–60%. The anti-biofouling effect of the np-Au electrode is discussed on the basis of the balance between its pore size and protein size, including the electrostatic repulsion with proteins.

Delineating the embodied CO2 emissions in Canada's exports: Routes, drivers, and paths

AbstractThis study combined the World Input–Output Database and Asian Development Bank's Multiregional Input–Output database to investigate Canada's embodied CO2 emissions in exports (EEE) for the period of 2000–2018. We examined the key drivers and paths through structural decomposition analysis and structural path analysis. First, the results showed that embodied emissions in the intermediate exports were the major contributor to Canada's EEE, and emission paths involving more than three countries were on the rise, indicating that the expansion of the global industrial supply chains has complicated the paths of Canada's EEE. Second, the factors such as emission intensity of sectors, export structure, and export scale, had varying influences on Canada's EEE over time. For several sectors, the benefit from reduced emission intensity was largely offset by the additional emissions from the increased export scale. Hence, the design of emission regulations should consider the heterogeneity of industrial sectors in order to mitigate emissions for the diverse industries in Canada. Third, energy and resource industries (e.g., electricity, petroleum, wood, metals, and so on) played an essential role in Canada's exports. A significant amount of embodied emissions was transferred from these sectors to the downstream sectors along the supply chain, indicating that abatement measures should be adopted from the whole life cycle perspective of a product/service through an integrated governance of the supply chain. This article met the requirements for a Gold–Silver JIE data openness badge described at http://jie.click/badges.

Hypersensitive electrochemical sensor based on thermally annealed gold–silver alloy nanoporous matrices for the simultaneous determination of sulfathiazole and sulfamethoxazole residues in food samples

In this study, we have developed a novel, hypersensitive, and ultraselective electrochemical sensor containing thermally annealed gold–silver alloy nanoporous matrices (TA-Au-Ag-ANpM) integrated with f-MWCNTs-CPE and poly(l-serine) nanocomposites for the simultaneous detection of sulfathiazole (SFT) and sulfamethoxazole (SFM) residues in honey, beef, and egg samples. TA-Au-Ag-ANpM/f-MWCNTs-CPE/poly(l-serine) was characterized using an extensive array of analytical (UV–Vis, FT-IR, XRD, SEM, and EDX), and electrochemical (EIS, CV and SWV) techniques. It exhibited outstanding performance over a wide linear range, from 4.0 pM to 490 μM for SFT and 4.0 pM to 520 μM for SFM, with picomolar detection and quantification limits (0.53 pM and 1.75 pM for SFT, 0.41 pM and 1.35 pM for SFM, respectively). The sensor demonstrated exceptional repeatability, reproducibility, and anti-interference capability, with percentage recovery of 95.6–102.4% in food samples and RSD below 5%. Therefore, the developed sensor is an ideal tool to address the current antibiotic residue crisis in food sources.