Mina Zolfaghari, Abbas Yadegar, Atefe Rezaei
et al.
In the present research, zinc oxide (ZnO) nanoparticles (NPs) were biosynthesized through reduction by Anvillea garcinii leaf extract. A. garcinii leaves contain bioactive sesquiterpenes, terpenoids, and phenolic compounds, which are likely responsible for the reduction and stabilization of ZnO NPs. Compared to conventional physicochemical approaches, this synthesis method has several advantages, including simplicity, low cost, sustainability, and replicability. In this study, the impacts of various calcination (annealing) temperatures (60 °C and 500 °C) and different pHs (8, 10, and 12) on the properties of green-synthesized ZnO NPs were evaluated. Characterization was performed by analytical instruments including UV-Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) analyses, nanoparticle analyzer, and field emission scanning electron microscope (FE-SEM). The UV–Vis adsorption spectra of the ZnO NPs revealed a prominent peak at approximately 230 nm. The observed peaks in FTIR spectra align well with those reported in various studies on ZnO NPs. By microscopic observation and XRD validation, the spherical and hexagonal nature of ZnO NPs was confirmed. The pH and temperature used were effective on the particle size, so that the smallest NPs (16.4 nm) were obtained with the help of the most alkaline synthesis medium (pH 12) and oven drying (60 °C). While the largest dimension (63 nm) corresponded to the NPs synthesized under the lowest pH (8) and dried with a 500 °C furnace. Synthesized NPs exhibited high antioxidant properties. The small sizes of biosynthesized ZnO NPs and their phytochemical-coated surfaces affected their biological activity. The cytotoxic impact of NPs on the gastric cancer cells was dose-dependent, and IC50 values for ZnO prepared at 60 and 500 °C (coded as ZnO-60 and ZnO-500) were 35.11 and 42.7 μg/mL respectively. In addition, they were potent antimicrobial agents against Gram-negative bacteria Escherichia coli and 3 strains of Helicobacter pylori, and Gram-positive bacterium Staphylococcus aureus. The green synthesis of ZnO NPs represents a sustainable approach that minimizes environmental impact while producing effective nanomaterials. By using natural plant extracts, researchers can develop cost-effective and eco-friendly methods for NP production, enhancing their potential applications across diverse sectors such as medical fields, environmental science, and materials engineering.
Abstract Understanding the relationship between tropical heavy rainfall and large-scale circulation provides valuable insights for improving the climate models. Here we use Gaussian Mixture Model to identify two distinct types of heavy rainfall over the tropical Pacific, “strong deep convection” and “moderately strong deep convection,” using satellite-borne precipitation radar measurements. They differ in two typical climatological deep convection-related rainfall modes between the western and eastern Pacific regions. The occurrence frequency of moderately strong deep convection is significantly different between the western and eastern Pacific, potentially linked to the Walker circulation. The enhanced Walker circulation appears to weaken the local Hadley circulation, thereby reducing strong deep convective activity in the eastern Pacific. This increases moderately heavy rainfall and decreases diabatic heating, which can affect global climate. We propose incorporating the close link between large-scale Walker circulation and mesoscale heavy convective rainfall into the current climate models.
Abstract Secondary organic aerosol (SOA) comprises most of the submicron atmospheric particle mass, and often becomes internally mixed with other particles. When SOA mixes with transition metal (e.g., iron) containing particles, metal-organic complexes can form, enabling photochemical reactions that change aerosol physicochemical properties. We studied the photochemistry of α-pinene SOA formed on iron-containing ammonium sulfate seed particles at varying relative humidities (RH). Chemical composition and photochemical reduction of particles were analyzed by X-ray spectromicroscopy and infrared spectroscopy. SOA formed at low vs. high RH had different chemical functionality, including abundant carboxylic acids and alcohols. Following photolysis, carboxylic acids and unsubstituted alkanes decreased, and alcohols increased, consistent with decarboxylation reactions. Iron in SOA formed at high RH was readily photochemically reduced, but iron in SOA formed at low RH was not. Overall, RH conditions at SOA formation affect not only chemical composition but also iron-complex formation and hence photochemical processing of aerosols.
Zaher Abdel Baki, Sahar H. Abourida, Adnan Badran
et al.
Bread is an indispensable staple food and a great source of complex carbohydrates, making it a potential product for fortification. The purpose of this study was to investigate the sensory, antioxidant, and nutritional properties of bread fortified with sumac (Rhus coriaria) and cactus (Opuntia ficus-indica L.) seed powder. Different levels (4, 6, and 8% w/w flour replacement) of the powdered seeds were used. Fortified bread samples were compared to control (unfortified) bread and evaluated for their moisture, nutritional composition (protein, fat, fiber, ash, carbohydrates, and energy value), sensory preference, total phenolic content (TPC), and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl assay). The antioxidant capacity and TPC were significantly higher (p<0.05) for sumac- and cactus-fortified bread samples compared to the control. Nutritionally, fortification significantly increased fiber and fat content while decreasing carbohydrate content and energy value (p<0.05); protein content remained relatively stable. Sensory evaluation showed a preference for sumac-fortified bread, particularly at lower concentrations. Moisture content was significantly lower in fortified samples. This study demonstrates that fortification, particularly with 8% sumac, yielded favorable results concerning antioxidant activity, phenolic content, and sensory preference, alongside notable changes in nutritional composition.
K. Larsen, R. Lukyanenko, Roland M. Mueller
et al.
Researchers must ensure that the claims about the knowledge produced by their work are valid. However, validity is neither well-understood nor consistently established in design science, which involves the development and evaluation of artifacts (models, methods, instantiations, and theories) to solve problems. As a result, it is challenging to demonstrate and communicate the validity of knowledge claims about artifacts. This paper defines validity in design science and derives the Design Science Validity Framework and a process model for applying it. The framework comprises three high-level claim and validity types-criterion, causal, and context-as well as validity subtypes. The framework guides researchers in integrating validity considerations into projects employing design science and contributes to the growing body of research on design science methodology. It also provides a systematic way to articulate and validate the knowledge claims of design science projects. We apply the framework to examples from existing research and then use it to demonstrate the validity of knowledge claims about the framework itself.
1Centre for Marine Science & Innovation and Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, UNSW Australia, Sydney, New South Wales, Australia; 2Sydney Institute of Marine Science, Mosman, New South Wales, Australia; 3Department of Primary Industries, New South Wales Fisheries, Coffs Harbour, New South Wales, Australia; 4National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales, Australia; 5School of Biological Sciences, UWA Oceans Institute, University of Western Australia, Crawley, Western Australia, Australia; 6Department of Science and Environment (DSE), Roskilde University, Roskilde, Denmark and 7Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technical University, Singapore City, Singapore
In search of the right diamond defect Certain defects in diamond are among the most promising physical implementations of qubits, the building blocks of quantum computers. However, identifying a defect with balanced properties is tricky: Nitrogen vacancy centers have a long lifetime but comparatively poor optical properties, whereas negatively charged silicon vacancy centers have the opposite characteristics. Rose et al. used careful materials engineering to stabilize the neutral charge state of silicon vacancy centers and found that they combine long coherence times with excellent optical properties. Science, this issue p. 60 The neutral charge state of silicon vacancy centers in diamond shows promising quantum information properties. Engineering coherent systems is a central goal of quantum science. Color centers in diamond are a promising approach, with the potential to combine the coherence of atoms with the scalability of a solid-state platform. We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful materials engineering, we achieved >80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching 1 minute and coherence times approaching 1 second. Its optical properties are very favorable, with ~90% of its emission into the zero-phonon line and near–transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum network applications.
The number of scholarly documents available on the web is estimated using capture/recapture methods by studying the coverage of two major academic search engines: Google Scholar and Microsoft Academic Search. Our estimates show that at least 114 million English-language scholarly documents are accessible on the web, of which Google Scholar has nearly 100 million. Of these, we estimate that at least 27 million (24%) are freely available since they do not require a subscription or payment of any kind. In addition, at a finer scale, we also estimate the number of scholarly documents on the web for fifteen fields: Agricultural Science, Arts and Humanities, Biology, Chemistry, Computer Science, Economics and Business, Engineering, Environmental Sciences, Geosciences, Material Science, Mathematics, Medicine, Physics, Social Sciences, and Multidisciplinary, as defined by Microsoft Academic Search. In addition, we show that among these fields the percentage of documents defined as freely available varies significantly, i.e., from 12 to 50%.
Owing to their remarkable thermal–hydraulic performance, vapor chambers have diverse applications, especially for cooling electronic devices. However, the performances of circular and noncircular pillars throughout the entire vapor chamber under identical wick volume conditions have been compared in very few studies. In this study, a series of noncircular pillar arrays featuring biomimetic tree-like fractal networks is introduced. The incorporation of fractal pillars significantly enhances the thermal–hydraulic performance of the vapor chamber because the gas–liquid interface area is extended. Compared to a vapor chamber with circular pillars, the maximum condensation surface temperature difference, total thermal resistance, and liquid pressure drop of this vapor chamber with fractal pillars are reduced by up to 57.8 %, 13.8 %, and 10.9 %, respectively. In particular, with large branch levels and pillar diameters, the fractal structure is pivotal for boosting the overall performance. When the number of pillars is increased, the fractal structure's impact on the thermal performance reaches a limit, whereas its boosting effect on the flow performance weakens. This study is a pioneering exploration of the application of stretched geometries in pillar-type vapor chambers, with fractal pillars utilized in showcase demonstrations.
The seasonal dynamics of phytoplankton communities in Korean coastal waters (KCWs) are influenced by complex interactions between ocean currents and nearshore human activities. Despite these influences, the understanding of seasonal phytoplankton changes and their environmental relationships in KCWs remains limited. We investigate the influence of the distinct characteristics of the three seas surrounding the KCWs (the Yellow Sea, the South Sea, and the East Sea) on seasonal phytoplankton communities based on field surveys conducted at 23 stations between 2020 and 2021. The East Sea exhibited higher winter temperatures due to the Jeju and Tsushima warm currents, while summer temperatures were lower compared to the other regions, highlighting the role of currents and deeper oceanic waters. The Yellow Sea showed significant freshwater influence with low salinity levels from major rivers, contrasting with the higher salinity in the East Sea. These differences led to a disparity in the productivity of the two regions: the highest value of Chl. <i>a</i> was observed to be 6.05 µg L<sup>−1</sup> in the Yellow Sea in summer. Diatoms dominated in nutrient-rich conditions, particularly in the Yellow Sea, where they comprised up to 80–100% of the phytoplankton community in summer, winter, and spring. PCA analysis revealed positive correlations between diatoms and Chl. <i>a</i>, while cryptophytes, which thrive in the absence of diatom proliferation, showed no such correlation, indicating their opportunistic growth in nutrient-limited conditions. This study highlights the significant impact of region-specific hydrographic factors on phytoplankton communities in KCWs, with diatoms dominating in summer and cryptophytes and dinoflagellates showing seasonal and regional variations. Understanding these dynamics is crucial for predicting phytoplankton bloom dynamics and their ecological implications in coastal ecosystems.
BACKGROUND AND OBJECTIVES: The utilization of disposable masks during and subsequent to the COVID-19 pandemic has led to the emergence of mask waste. The bacteria that thrive on mask waste have special characteristics. The objective of this research was to identify, choose, and analyze the bacteria present in discarded face masks at landfill sites (Piyungan, Yogyakarta and Jatibarang, Semarang), coastal areas (Tanjung Pasir, Tangerang, and Marina, Semarang), as well as mangrove forests (Teluk Naga, Tangerang, and Tirang, Semarang) situated in Java, Indonesia.METHODS: The bacterial isolation was performed using minimal salt medium. Bacterial isolates were screened in a minimal salt medium supplemented with three types of masks (black duckbill, blue medical, white Korean filter) as the sole carbon and energy source at the various potential of hydrogen levels (5, 7, 9), temperatures (10, 30, 50 degrees Celsius), and sodium chloride concentrations (2.5, 5.0, 7.5 percent). The bacterial strains with the highest optical density values across all treatments were determined through the sequencing of the 16S ribosomal ribonucleic acid gene. These selected bacteria were then evaluated for their ability to produce biofilms under different potential of hydrogen and salt concentrations. The resistance to heavy metals (lead, copper, iron) and antibiotics (penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, kanamycin) was also investigated.FINDINGS: A grand total of 183 bacterial strains were obtained, comprising 80 isolates from landfills, 47 isolates from beaches, and 56 isolates from mangroves. The selected bacteria identified as Bacillus cereus, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus sciuri, and Staphylococcus arlettae based on 16 svedberg ribosomal ribonucleic acid gene analysis. The chosen strains exhibited the capacity to generate biofilm across various potential of hydrogen and salinity conditions. Furthermore, these strains displayed resilience to heavy metals (such as lead, copper, and iron) as well as resistance to antibiotics (including penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, and kanamycin).CONCLUSION: Mask waste discovered in landfills, beaches, and mangroves can promote bacterial growth. This study indicated that the selected bacteria are capable of flourishing through the utilization of various mask types as their exclusive carbon and energy source across a wide range of potential of hydrogen levels, temperatures, and salinity concentrations. The ability to produce biofilms, withstand antibiotics, and endure heavy metal ions provides a protective environment for bacteria, enhancing their resilience against environmental stresses, and antimicrobial agents. Analysis of bacterial profiles reveals the intricate connections between microorganisms and their surroundings. The results of this study have implications for public health, environmental pollution, and ecosystem dynamics.
This manuscript focuses on analyzing the growth dynamics of the Central Taiwan Science Park (CTSP) and Silicon Glen in Scotland with a specific emphasis on their approaches to energy, environmental conservation, and economic management. The objective is to provide insights into their sustainable development strategies. In terms of energy, CTSP addresses Taiwan’s energy security and green transformation challenges, while Silicon Glen concentrates on Scotland’s wind energy generation technologies. Both regions prioritize the advancement of renewable energy sources and smart grid technologies. In the realm of environmental conservation, both CTSP and Silicon Glen prioritize environmental protection and sustainability by implementing rigorous environmental monitoring measures. Regarding economic management, CTSP and Silicon Glen serve as vital technology industry hubs in Taiwan and Scotland, respectively, attracting a multitude of high-tech and startup enterprises. This growth is facilitated through various means, including policy support, access to research resources, and robust infrastructure. This manuscript presents a comparative analysis of these two industrial parks, focusing on their environmental and economic management strategies. It aims to elucidate the principles underpinning the sustainable development and economic growth of industrial parks, offering valuable insights to decision-makers and stakeholders involved in the planning of sustainable industrial parks.
Hani A. Mashout, Taha A. Razek, Mohamed S. Amin
et al.
Abstract In Egypt, basalt manufacturing generates waste materials at a rate of about 33%. The disposal of basalt waste through the manufacturing of cementitious materials is an economically feasible approach. This work involved the fabrication of a one-part slag/basalt waste geopolymer cement (GP) enhanced by nano-TiO2. The physico-mechanical properties of the different GP mixes were investigated. The durability against fire at up to 750 °C, sulfate (SO4 −2) attack, and irradiation with significant dosages of γ-rays at up to 1500 kGy were assessed. Phase composition and microstructure were explored through various techniques as XRD, TG, and SEM. The findings demonstrated that basalt incorporation up to 20% within the GP mix boosted its mechanical characteristics after 28 and 90 days of curing by 8.5 and 2.5%, respectively, while 60% replacement diminished the strength by 30%. Slag/basalt GP showed a comprehensible resistance to SO4 −2 ions attack, and its strength was intensified by 14% after 4 months of immersion. Additionally, the blended GP mixes could preserve 40% of their strength after being exposed to 1500 kGy of γ-rays and about 50% of their strength after firing at 750 °C. Admixing GP by NT showed a synergic impact for diminishing setting times, boosting compressive strength by 5 ~ 15% compared to reference mix along with an improvement in the microstructure. Furthermore, distributing NT through GP greatly improved durability after firing at 500 and 700 °C and irradiating with high dosages of γ-rays. This feature is mostly connected to the catalytic capabilities and filling activities of NT in boosting geopolymerization processes.
Yuki Okamoto, Keisuke Imoto, Shinnosuke Takamichi
et al.
One way of expressing an environmental sound is using vocal imitations, which involve the process of replicating or mimicking the rhythm and pitch of sounds by voice. We can effectively express the features of environmental sounds, such as rhythm and pitch, using vocal imitations, which cannot be expressed by conventional input information, such as sound event labels, images, or texts, in an environmental sound synthesis model. In this paper, we propose a framework for environmental sound synthesis from vocal imitations and sound event labels based on a framework of a vector quantized encoder and the Tacotron2 decoder. Using vocal imitations is expected to control the pitch and rhythm of the synthesized sound, which only sound event labels cannot control. Our objective and subjective experimental results show that vocal imitations effectively control the pitch and rhythm of synthesized sounds.