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12 pages, 921 KiB

Open AccessArticle

Performance Analysis of Deep Learning Model-Compression Techniques for Audio Classification on Edge Devices

by Afsana Mou and Mariofanna Milanova

Sci 2024, 6(2), 21; https://doi.org/10.3390/sci6020021 - 02 Apr 2024

Viewed by 622

Audio classification using deep learning models, which is essential for applications like voice assistants and music analysis, faces challenges when deployed on edge devices due to their limited computational resources and memory. Achieving a balance between performance, efficiency, and accuracy is a significant [...] Read more.

Audio classification using deep learning models, which is essential for applications like voice assistants and music analysis, faces challenges when deployed on edge devices due to their limited computational resources and memory. Achieving a balance between performance, efficiency, and accuracy is a significant obstacle to optimizing these models for such constrained environments. In this investigation, we evaluate diverse deep learning architectures, including Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM), for audio classification tasks on the ESC 50, UrbanSound8k, and Audio Set datasets. Our empirical findings indicate that Mel spectrograms outperform raw audio data, attributing this enhancement to their synergistic alignment with advanced image classification algorithms and their congruence with human auditory perception. To address the constraints of model size, we apply model-compression techniques, notably magnitude pruning, Taylor pruning, and 8-bit quantization. The research demonstrates that a hybrid pruned model achieves a commendable accuracy rate of 89 percent, which, although marginally lower than the 92 percent accuracy of the uncompressed CNN, strikingly illustrates an equilibrium between efficiency and performance. Subsequently, we deploy the optimized model on the Raspberry Pi 4 and NVIDIA Jetson Nano platforms for audio classification tasks. These findings highlight the significant potential of model-compression strategies in enabling effective deep learning applications on resource-limited devices, with minimal compromise on accuracy. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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18 pages, 3736 KiB

Open AccessArticle

Colorimetric Determination of Salivary Cortisol Levels in Artificial Saliva for the Development of a Portable Colorimetric Sensor (Salitrack)

by Tashfia Ahmed, Michael B. Powner, Meha Qassem and Panayiotis A. Kyriacou

Sci 2024, 6(2), 20; https://doi.org/10.3390/sci6020020 - 02 Apr 2024

Viewed by 607

Abstract

Mental illnesses, such as clinical depression, have taken an unprecedented toll on society and the economy on a global scale. The relationship between stress management and mental health decline is of utmost significance, especially as most avenues of mental health management remain inaccessible [...] Read more.

Mental illnesses, such as clinical depression, have taken an unprecedented toll on society and the economy on a global scale. The relationship between stress management and mental health decline is of utmost significance, especially as most avenues of mental health management remain inaccessible for the majority of the general public, i.e., interview-based, and face-to-face interventions or costly drug-based therapies. Cortisol, the primary stress hormone, regulates the stress response in the human body and, through persistent activation, can lead to chronic stress and mental health deterioration. Thereby, the measurement and evaluation of cortisol within saliva could harness potential developments in management and diagnostic tools to monitor physiological and psychological stress in simple point-of-care applications. The current study aims to determine the concentration of salivary cortisol in spiked artificial saliva samples using blue tetrazolium (BT) dye as a colorimetric indicator. The proposed method showcases the use of the BT dye as an effective method for the rapid measurement of salivary cortisol, with accuracy comparable to the gold-standard method for salivary cortisol analysis, enzyme-linked immunoassays (ELISAs). Finally, a prototype colorimetric sensor has been developed for point-of-care applications of stress monitoring via salivary cortisol measurement. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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13 pages, 769 KiB

Open AccessArticle

Mood Profile Clusters among Greek Exercise Participants and Inactive Adults

by Peter C. Terry, Renée L. Parsons-Smith, Symeon P. Vlachopoulos and Andrew M. Lane

Sci 2024, 6(2), 18; https://doi.org/10.3390/sci6020018 - 26 Mar 2024

Viewed by 745

Abstract

Mood profile clusters have previously been identified in several cultural contexts. In the present study, six mood profile clusters referred to as the iceberg, inverse Everest, inverse iceberg, shark fin, submerged, and surface profiles, were investigated in a Greek population. The names of [...] Read more.

Mood profile clusters have previously been identified in several cultural contexts. In the present study, six mood profile clusters referred to as the iceberg, inverse Everest, inverse iceberg, shark fin, submerged, and surface profiles, were investigated in a Greek population. The names of the mood profiles reflect how they appear after raw scores for Tension, Depression, Anger, Vigor, Fatigue, and Confusion (in that order), are converted to T-scores and depicted graphically. A Greek translation of the Brunel Mood Scale (BRUMS-Greek) was completed by 1786 adults, comprising 1417 exercise participants and 369 physically inactive adults (male = 578, female = 1208) aged 18–64 years (M = 34.73 ± 11.81 years). Although the male–female ratio emphasized females, sample sizes of over 500 suggest some degree of representativeness. Seeded k-means cluster analysis clearly identified the six hypothesized mood profiles. Men were over-represented for the iceberg profile. For age, the 18–25 years group were under-represented for the iceberg profile, whereas the 46–55 and 56+ years groups were over-represented. The 56+ years group were under-represented for the inverse Everest, and the 18–25 years group were over-represented for the shark fin profile. For body mass index (BMI), participants in the obese weight category were over-represented for the inverse iceberg and shark fin profiles and under-represented for the submerged profile. Active participants were over-represented for the iceberg and submerged profiles, and under-represented for the inverse Everest, inverse iceberg, and surface profiles. Findings supported the cross-cultural equivalence of the mood profile clusters and confirmed the link between physical inactivity, obesity, and negative mood profiles. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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28 pages, 8339 KiB

Open AccessArticle

Net Isotopic Signature of Atmospheric CO₂ Sources and Sinks: No Change since the Little Ice Age

by Demetris Koutsoyiannis

Sci 2024, 6(1), 17; https://doi.org/10.3390/sci6010017 - 14 Mar 2024

Viewed by 15303

Abstract

Recent studies have provided evidence, based on analyses of instrumental measurements of the last seven decades, for a unidirectional, potentially causal link between temperature as the cause and carbon dioxide concentration ([CO₂]) as the effect. In the most recent study, this [...] Read more.

Recent studies have provided evidence, based on analyses of instrumental measurements of the last seven decades, for a unidirectional, potentially causal link between temperature as the cause and carbon dioxide concentration ([CO₂]) as the effect. In the most recent study, this finding was supported by analysing the carbon cycle and showing that the natural [CO₂] changes due to temperature rise are far larger (by a factor > 3) than human emissions, while the latter are no larger than 4% of the total. Here, we provide additional support for these findings by examining the signatures of the stable carbon isotopes, 12 and 13. Examining isotopic data in four important observation sites, we show that the standard metric δ¹³C is consistent with an input isotopic signature that is stable over the entire period of observations (>40 years), i.e., not affected by increases in human CO₂ emissions. In addition, proxy data covering the period after 1500 AD also show stable behaviour. These findings confirm the major role of the biosphere in the carbon cycle and a non-discernible signature of humans. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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12 pages, 2959 KiB

Open AccessArticle

Cyclic Voltammetric Behaviour and High-Performance Liquid Chromatography Amperometric Determination of Levamisole

by Tsz Yan Joyce Chan and Kevin C. Honeychurch

Sci 2024, 6(1), 15; https://doi.org/10.3390/sci6010015 - 08 Mar 2024

Viewed by 818

Abstract

The electrochemical oxidation of levamisole, a glassy carbon electrode, was investigated over the pH range 2.0–10.0. Cyclic voltammetric investigations showed a single oxidation process was recorded, with a peak potential (E_p) shown to be pH-dependent in the range 5.0–8.0; between [...] Read more.

The electrochemical oxidation of levamisole, a glassy carbon electrode, was investigated over the pH range 2.0–10.0. Cyclic voltammetric investigations showed a single oxidation process was recorded, with a peak potential (E_p) shown to be pH-dependent in the range 5.0–8.0; between pH 2.0 and pH 5.0, and above pH 8.0, the E_p was found to be independent of pH, indicating apparent pKa values of 5.0 and 8.0. Peak currents were found to increase with increasing pH values. This voltammetric oxidation process was found to be consistent with a two-electron, two-proton oxidation to the corresponding sulfoxide. Based on these findings, the development of a of method based on the high-performance liquid chromatography separation of levamisole, with electrochemical detection being used for its determination, was explored. The chromatographic conditions required for the separation of levamisole were first investigated and optimized using UV detection. The conditions were identified as a 150 mm × 4.6 mm, 5 µm C₁₈ column with a mobile phase consisting of 50% methanol, and 50%, 50 mM, pH 8.0 phosphate buffer. The technique of hydrodynamic voltammetry was applied to optimize the applied potential required for the determination of levamisole, identified as +2.3 V versus a stainless-steel pseudo-reference counter-electrode. Under the optimized conditions, levamisole exhibited a linear response of 1.00–20 mg/L (R² = 0.999), with a detection limit of 0.27 mg/L. The possibility of determining levamisole in artificial urine was shown to be possible via simple dilution in the mobile phase. Mean recoveries of 99.7%, and 94.6%, with associated coefficients of variation of 8.2% and 10.2%, respectively, were obtained for 1.25 µg/mL (n = 5) and 2.50 µg/mL (n = 5). Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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11 pages, 1293 KiB

Open AccessArticle

Early-Wood vs. Late-Wood in Scots Pine: Finding Stable Relationships in Elemental Distribution

by Vladimir L. Gavrikov, Alexey I. Fertikov, Ruslan A. Sharafutdinov, Zhonghua Tang and Eugene A. Vaganov

Sci 2024, 6(1), 4; https://doi.org/10.3390/sci6010004 - 28 Dec 2023

Viewed by 1592

Abstract

This study explored whether consistent differences can be found between early-wood and late-wood in terms of elemental content of tree rings. The species to study was Pinus sylvestris L. growing within an even-aged stand planted during the early 1970s in eastern Siberia. The [...] Read more.

This study explored whether consistent differences can be found between early-wood and late-wood in terms of elemental content of tree rings. The species to study was Pinus sylvestris L. growing within an even-aged stand planted during the early 1970s in eastern Siberia. The wood specimens were extracted from the north and south sides of trees and subsequently scanned through an X-ray fluorescent facility Itrax Multiscanner. A sequence of relatively wide tree-rings was chosen for the analysis. The scanning data on a number of elements (Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Sr, and Hg) were split into early-wood and late-wood data for each year of growth. The early- and late-wood data in the same ring were analyzed for basic statistics against each other as well as against available meteorological data. In the northern direction, the elements Al, Si, P, Cl, Cu, and Zn are always more abundant in the late-wood, while Ca, Fe, and Sr are always more abundant in the early-wood. What is important is how the differences for P, Ca, Fe, Cu, Zn, and Sr were always significant. The calcium content in the early-wood was the most consistently reflective regarding the meteorological data for the early summer (June). In some trees, the late-wood K content was well correlated with the Vysotskii–Ivanov climatic index. In the southern direction, Cu and Zn were always more abundant in the late-wood, while Sr was more abundant in the early-wood. The differences for all three elements were always significant. The cases of consistent relationships, though rare, help to develop a research program in the area of dendrochemistry. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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16 pages, 270 KiB

Open AccessArticle

The Perceptions of Generation Z University Students about Their Futures: A Qualitative Study

by Gül Dikeç, Simge Öztürk, Neslihan Taşbaşı, Damla Figenergül and Bilal Buğrahan Güler

Sci 2023, 5(4), 45; https://doi.org/10.3390/sci5040045 - 08 Dec 2023

Viewed by 1716

Abstract

This study explored the future-oriented perceptions of Generation Z students in a foundation university. This study was conducted using qualitative research and a phenomenological design. The study sample consisted of 11 university students over the age of 18 who agreed to participate in [...] Read more.

This study explored the future-oriented perceptions of Generation Z students in a foundation university. This study was conducted using qualitative research and a phenomenological design. The study sample consisted of 11 university students over the age of 18 who agreed to participate in the study. Data were collected online through individual interviews in Türkiye. Colaizzi’s phenomenological analysis method was used in the data analysis. The content analysis determined three main themes and eleven sub-themes. The first theme was the students’ knowledge acquisition about the “current situation of the country.” Under this theme were four sub-themes: economic problems, the immigrant situation, the education and justice system, and the country’s agenda. In the second theme, students shared their opinions about “being a student in the country.” This theme included economic impossibilities, their participation in limited social activities, and housing problems. In the last theme, “future anxiety,” the sub-themes of the students were found to include experiences hopelessness versus hope. Uncertainty caused anxiety, as did going abroad, finding a job, and improving themselves. It was determined that the participants were worried about the current situation in the countries they lived in during this period due to economic problems; while some were hopeful about the future, some were hopeless and would go abroad. This study might contribute to the literature on determining the future-oriented perceptions, possible stressors and hope levels of Generation Z university students in Türkiye. Additionally, intervention programs can be developed for the management these stressors to protect the mental health of Generation Z university students. On the other hand, it is necessary to protect the mental health of young people, who are the adults of the future, and to create policies for the youth of this country where social opportunities are maintained. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

15 pages, 3950 KiB

Open AccessArticle

Development of Tannic Acid Coated Polyvinylidene Fluoride Membrane for Filtration of River Water Containing High Natural Organic Matter

by Rosmaya Dewi, Norazanita Shamsuddin, Muhammad Saifullah Abu Bakar, Sutarat Thongratkaew, Kajornsak Faungnawakij and Muhammad Roil Bilad

Sci 2023, 5(4), 42; https://doi.org/10.3390/sci5040042 - 20 Nov 2023

Viewed by 1311

Abstract

River water can be used as a source of drinking water. However, it is vital to consider the existence of natural organic matter (NOM) and its possible influence on water quality (low turbidity, high color). The level of NOM in river water significantly [...] Read more.

River water can be used as a source of drinking water. However, it is vital to consider the existence of natural organic matter (NOM) and its possible influence on water quality (low turbidity, high color). The level of NOM in river water significantly impacts the ecosystem’s health and the water’s quality, and needs to be removed. A membrane-based approach is attractive for treating NOM successfully, but is still hindered by the membrane fouling problem. This study aims to develop polyvinylidene fluoride (PVDF)-based membranes customized for NOM removal from river water. The anti-fouling property was imposed by a coating of tannic acid (TA) and Fe³⁺ on the pre-prepared PVDF membrane. The results show that the TA–Fe coatings were effective, as demonstrated by the FTIR spectra, SEM, and EDS data. The coatings made the membrane more hydrophilic, with smaller pore size and lower clean water permeability. Such properties offer enhanced NOM rejections (up to 100%) and remarkably higher fouling recovery (up to 23%), desirable for maintaining a long-term filtration performance. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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14 pages, 12463 KiB

Open AccessArticle

In Silico Study of Potential Small Molecule TIPE2 Inhibitors for the Treatment of Cancer

by Jerica Wilson, Katerina Evangelou, Youhai H. Chen and Hai-Feng Ji

Sci 2023, 5(4), 39; https://doi.org/10.3390/sci5040039 - 07 Oct 2023

Viewed by 1307

Abstract

Context: Chronic inflammation has been linked to cancer since the 19th century. Tumor growth is supported by the proangiogenic factors that chronic inflammation requires. Polarized leukocytes initiate these angiogenic and tumorigenic factors. TIPE2, a transport protein, manages the cytoskeletal rearrangement that gives a [...] Read more.

Context: Chronic inflammation has been linked to cancer since the 19th century. Tumor growth is supported by the proangiogenic factors that chronic inflammation requires. Polarized leukocytes initiate these angiogenic and tumorigenic factors. TIPE2, a transport protein, manages the cytoskeletal rearrangement that gives a polarized leukocyte its motility. Inhibition of this protein could lead to a therapeutic option for solid tumor cancers; however, no such inhibitors have been developed so far due to the large cavity size of the TIPE2 protein. Here we have examined possible small molecule inhibitors by combining structure-based and fragment-based drug design approaches. The highest binding ligands were complexed with the protein, and fragment libraries were docked with the complex with the intention of linking the hit compounds and fragments to design a more potent ligand. Three hit compounds were identified by in silico structure-based screening and a linked compound, C2–F14, of excellent binding affinity, was identified by linking fragments to the hit compounds. C2–F14 demonstrates good binding stability in molecular dynamic simulations and great predicted ADME properties. Methods: High throughput molecular docking calculations of mass libraries were performed using AutoDock Vina 1.1.2. Molecular docking of individual ligands was performed using AutoDock Vina with PyRx. Ligand libraries were prepared using OpenBabel, linked ligands were prepared using Avogadro. The protein was prepared using AutoDockTools-1.5.6. Protein-ligand complexes were visualized with PyMOL. Two- and three-dimensional representations of protein–ligand interactions were plotted with BIOVIA Discovery Studio Visualizer. In silico absorption, distribution, metabolism, and excretion (ADME) properties were calculated using SwissADME. Molecular dynamics simulations were conducted with GROMACS. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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33 pages, 7565 KiB

Open AccessArticle

On Hens, Eggs, Temperatures and CO₂: Causal Links in Earth’s Atmosphere

by Demetris Koutsoyiannis, Christian Onof, Zbigniew W. Kundzewicz and Antonis Christofides

Sci 2023, 5(3), 35; https://doi.org/10.3390/sci5030035 - 13 Sep 2023

Cited by 3 | Viewed by 100506

Abstract

The scientific and wider interest in the relationship between atmospheric temperature (T) and concentration of carbon dioxide ([CO₂]) has been enormous. According to the commonly assumed causality link, increased [CO₂] causes a rise in T. However, [...] Read more.

The scientific and wider interest in the relationship between atmospheric temperature (T) and concentration of carbon dioxide ([CO₂]) has been enormous. According to the commonly assumed causality link, increased [CO₂] causes a rise in T. However, recent developments cast doubts on this assumption by showing that this relationship is of the hen-or-egg type, or even unidirectional but opposite in direction to the commonly assumed one. These developments include an advanced theoretical framework for testing causality based on the stochastic evaluation of a potentially causal link between two processes via the notion of the impulse response function. Using, on the one hand, this framework and further expanding it and, on the other hand, the longest available modern time series of globally averaged T and [CO₂], we shed light on the potential causality between these two processes. All evidence resulting from the analyses suggests a unidirectional, potentially causal link with T as the cause and [CO₂] as the effect. That link is not represented in climate models, whose outputs are also examined using the same framework, resulting in a link opposite the one found when the real measurements are used. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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Review

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13 pages, 254 KiB

Open AccessReview

The Impacts of the African Growth Opportunity Act on the Economic Performances of Sub-Saharan African Countries: A Comprehensive Review

by Bedassa Tadesse

Sci 2024, 6(1), 14; https://doi.org/10.3390/sci6010014 - 01 Mar 2024

Viewed by 1290

Abstract

The African Growth Opportunity Act (AGOA) has been a crucial trade and development initiative, offering preferential access to qualified Sub-Saharan African (SSA) countries to the United States market since its enactment in 2000. This paper presents a comprehensive review of scholarly articles and [...] Read more.

The African Growth Opportunity Act (AGOA) has been a crucial trade and development initiative, offering preferential access to qualified Sub-Saharan African (SSA) countries to the United States market since its enactment in 2000. This paper presents a comprehensive review of scholarly articles and policy reports that analyze the impact of AGOA on the economic performance of SSA countries. Employing various econometric methods and data analysis techniques, researchers have investigated the effects of AGOA on trade flows, foreign direct investment (FDI) inflows, employment, economic growth, and poverty levels. The findings reveal that AGOA has positively affected the region’s trade, particularly in apparel, textiles, and agriculture. However, its influence on promoting export diversification and attracting FDI is nuanced, with substantial heterogeneity among the beneficiary countries and industries within each country. While some SSA countries have experienced substantial export growth and FDI inflows, others have not fully leveraged the benefits of AGOA due to absorptive capacity constraints and governance challenges. AGOA’s effectiveness in promoting broad-based employment, GDP growth, and poverty reduction remains an active area of inquiry, necessitating further research to understand the policy’s sustained impact and inform future trade policy designs for SSA countries. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

16 pages, 1868 KiB

Open AccessReview

Privacy and Security of Blockchain in Healthcare: Applications, Challenges, and Future Perspectives

by Hamed Taherdoost

Sci 2023, 5(4), 41; https://doi.org/10.3390/sci5040041 - 30 Oct 2023

Cited by 3 | Viewed by 4927

Abstract

Blockchain offers a cutting-edge solution for storing medical data, carrying out medical transactions, and establishing trust for medical data integration and exchange in a decentralized open healthcare network setting. While blockchain in healthcare has garnered considerable attention, privacy and security concerns remain at [...] Read more.

Blockchain offers a cutting-edge solution for storing medical data, carrying out medical transactions, and establishing trust for medical data integration and exchange in a decentralized open healthcare network setting. While blockchain in healthcare has garnered considerable attention, privacy and security concerns remain at the center of the debate when adopting blockchain for information exchange in healthcare. This paper presents research on the subject of blockchain’s privacy and security in healthcare from 2017 to 2022. In light of the existing literature, this critical evaluation assesses the current state of affairs, with a particular emphasis on papers that deal with practical applications and difficulties. By providing a critical evaluation, this review provides insight into prospective future study directions and advances. Full article

(This article belongs to the Special Issue Feature Papers—Multidisciplinary Sciences 2023)

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