Hasil untuk "Chemical technology"

J. Coburn, H. F. Winters

Mainak Kundu, Ria Kanjilal, Ismail Uysal

Wireless sensor networks (WSNs) are widely used in IoT, environmental monitoring, and industrial systems, but ensuring energy efficiency, extended network lifetime, and reliable communication under real-world constraints remains challenging. This work proposes a novel clustering framework that integrates kernel density estimation (KDE)-based adaptive node deployment, silhouette-optimized K-means clustering, Bayesian cluster head (CH) selection with Gaussian noise-based energy uncertainty modeling, energy-efficient coverage control, and carrier sense multiple access with collision avoidance-based data transmission. Unlike conventional approaches that rely on fixed clustering and uniform deployments, our framework supports terrain-aware node placement and dynamic CH selection based on residual energy and distance under imperfect sensing conditions. Simulation results demonstrate significant improvements in performance, including over 35% extension in network lifetime and higher coverage retention under energy constraints, compared to baseline methods such as LEACH and K-LEACH. While detailed metrics vary per run due to adaptive parameters and stochastic node behavior, these outcomes validate the scalability, robustness, and practical relevance of the proposed method for real-world WSN deployments.

Huancai Fan, Dongyuan Lü, Zheng Lu et al.

Abstract Stem cell differentiation must be regulated by intricate and complex interactions between cells and their surrounding environment, ensuring normal organ and tissue morphology such as the liver1. Though it is well acknowledged that microgravity provides necessary mechanical force signals for cell fate2, how microgravity affects growth, differentiation, and communication is still largely unknown due to the lack of real experimental scenarios and reproducibility tools. Here, Rotating Flat Chamber (RFC) was used to simulate ground-based microgravity effects to study how microgravity effects affect the differentiation of HepaRG (hepatic progenitor cells) cells. Unexpectedly, the results show that RFC conditions could promote HepaRG cell differentiation which exhibited increased expression of Alpha-fetoprotein (AFP), albumin (ALB), and Recombinant Cytokeratin 18 (CK18). Through screening a series of mechanical receptors, the ion channel TRPML1 was critical for promoting the differentiation effect under RFC conditions. Once TRPML1 was activated by stimulated microgravity effects, the concentration of lysosomal calcium ions was increased to activate the Wnt/β-catenin signaling pathway, which finally led to enhanced cell differentiation of HepaRG cells. In addition, the cytoskeleton was remodeled under RFC conditions to influence the expression of PI (3,5) P2, which is the best-known activator of TRPML1. In summary, our findings have established a mechanism by which simulated microgravity promotes the differentiation of HepaRG cells through the TRPML1 signaling pathway, which provides a potential target for the regulation of hepatic stem/progenitor cell differentiation and embryonic liver development under real microgravity conditions.

Bhaskar Ahuja, Luca Gentile, Ajeet Kumar et al.

The growing population of space debris poses significant risks to operational satellites and future space missions, necessitating innovative and efficient tracking solutions. Ground-based radar for space surveillance has been a central area of research since the early Space Age, with recent advancements emphasizing the use of bistatic radar systems that incorporate sensitive radio telescopes as receivers. This approach offers a cost-effective and scalable solution for monitoring space debris. Preliminary observations demonstrated the viability of employing radio telescopes in bistatic configurations for effective debris tracking. This review provides a comprehensive analysis of experiments utilizing radio telescopes as bistatic receivers, highlighting key advancements, challenges, and potential applications in space surveillance systems. By detailing the progress in this field, this study underscores the critical role of bistatic radar systems in mitigating the growing threat of space debris.

Rahele Sadeghzadeh, Fatemeh Rafieian, Mahdi Keshani et al.

Pseudomonas aeruginosa is a Gram-negative human pathogenic bacterium that has the ability to form multicellular biofilm (BF) communities. Due to the presence of extracellular polymeric substances, BF protects bacteria from unfavorable environmental conditions and causes their resistance to antimicrobial substances. The presence of BF in the food industry has become a great threat to food safety. Conventional disinfection technologies are inappropriate for effective BF control due to the resistances created to them and the toxic residues for humans and the environment that they leave behind. Therefore, it is necessary to understand more about the formation and development of BF and environmentally friendly methods to remove BF from food and equipment in contact with food. This review article describes BF formation, its resistance mechanisms to antimicrobial agents, and BF development. Also, novel and effective strategies involved in BF removal are discussed including physical methods (plasma, pulsed electric field and ultrasonication), physicochemical method (electrolyzed water), biological methods (enzymes and bacteriophages), natural compounds such as essential oils, and application of nanomaterials.

Fetcia Jackulin, P. Senthil Kumar, Gayathri Rangasamy

Among the azo dye, Tartrazine is widely used for most of applications like pharmaceuticals, cosmetics, food, etc. As the demand for dye application is increased, the disposal of dye is also increasing. However it is very difficult to cleave due to its stability. Different methods are available, but the Advanced Oxidation Process (AOP) is an emerging technique used for treating various contaminants. In this study, sulfate radical (SO4−.) based AOP was performed to degrade tartrazine dye using iron oxide (Fe3O4) nanoparticles (NP). This NP was synthesized using the co-precipitation method, analyzed by X-Ray Diffraction (XRD), revealed the crystalline structure of the material and the average size of the particle was 16.17 nm also High Resolution- Scanning Electron Microscope (HR-SEM) showed spherical and cube shape of the particles with agglomeration. Response surface methodology (RSM) was carried out to determine the optimum condition based on central composite design. The optimum conditions were found to be pH-5.34, time- 113.58 min, NP- 0.89 g, SPS- 15.40 mM, and predicted degradation efficiency - 97.22% which was correlated to the experimental value- 96.66% with minimal error. Application of SO4−. radical implied an efficient degradation due to the involvement of both SO4−. and hydroxyl (OH-.) radical. Excess formation of SO4−. radicals, Fe2+ was majorily responsible for suppressive degradation. The intermediate compound was identified from Gas Chromatography-Mass Spectrometry (GC-MS), proved the absence of parent dye and occurrence of degradation due to Fe3O4/PS system.

Awwab Qasim Jumaah Althahab, Branislav Vuksanovic, Mohamed Al-Mosawi et al.

Intensive care units (ICUs) are busy and noisy areas where patients and professional staff can be exposed to acoustic noise for long periods of time. In many cases, noise levels significantly exceed the levels recommended by the official health organisations. This situation can affect not only patient recovery but also professional staff, making ICUs unhealthy work and treatment environments. To introduce the measures and reduce the acoustic noise in the ICU, acoustic noise levels should first be measured and then appropriately analysed. However, in most studies dealing with this problem, measurements have been performed manually over short periods, leading to limited data being collected. They are usually followed by insufficient analysis, which in turn results in inadequate measures and noise reduction. This paper reviews recent works dealing with the problem of excessively high noise levels in ICUs and proposes a more thorough analysis of measured data both in the time and frequency domains. Applied frequency domain analysis identifies the cyclic behaviour of the measured sound pressure levels (SPLs) and detects the dominant frequency components in the SPL time series. Moreover, statistical analyses are produced to depict the patterns and SPLs to which patients in ICUs are typically exposed during their stay in the ICU. It has been shown that the acoustic environment is very similar every night, while it can vary significantly during the day or evening periods. However, during most of the observed time, recorded SPLs were significantly above the prescribed values, indicating an urgent need for their control and reduction. To effectively tackle this problem, more detailed information about the nature of noise during each of the analysed periods of the day is needed. This issue will be addressed in the continuation of this project.

Antika Boondaeng, Sumaporn Kasemsumran, Kraireuk Ngowsuwan et al.

Pineapples are a tropical fruit with high nutritional value and high vitamin and sugar contents. In this study, low-grade pineapples were fermented to produce vinegar using surface culture fermentation (SCF), which involved the addition of dragon fruit juice, to compare the quality and antioxidant activity of different preparations of vinegar. The highest acetic acid concentration (7.35%) was obtained from pineapple vinegar after 20 days of incubation. Vinegar made from mixed pineapple and dragon fruit juice without peel and vinegar with pineapple and dragon fruit juice with peel had acetic acid concentrations of up to 6.20% and 4.50%, respectively. The mixed-fruit vinegar of pineapple and dragon fruit juice with peel displayed the highest antioxidant activity at 210.74 µg/g TE, while no significant difference was found between the other two vinegars (189.52 vs. 187.91 µg/L TE). Notably, the volatile compounds detected in the vinegars were alcohols and esters, which may contribute to the distinct aroma. Overall, the addition of dragon fruit juice with peel to pineapple vinegar increased the phenolic content and antioxidant activity; however, fermentation was slightly slower than that of the other two test materials.

Tengfei Wang, Danning Zheng, Beibei An et al.

Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure (0.1 MPa) without any solvent and co-catalyst leading to 96.1% product yield. It can be reused five times to keep the product yield over 90%. These intriguing results are attributed to a new reaction mechanism, which is supported by theoretical calculations along with the measurements of 13C NMR spectrum and Fourier transform infrared spectroscopy (FT-IR). The excellent catalytic activity can be traced to a CO2-philic group along with an electrophilic hydrogen atom. Our work shows that incorporation of CO2-philic group is an feasible pathway to develop the new efficient ionic liquids.

Kang Niu, Xi Chen, Di Yang et al.

To intercept the great maneuvering target, combining with the sliding mode and the extended disturbance observer, a new control algorithm for integrated guidance and control (IGC) system is proposed in this paper. Firstly, the paper formulates the Missile–Target problem. Then the paper establishes an uncertain IGC dynamic model where the nonlinearities, the perturbations and the maneuvering of the target are regarded as disturbance. Secondly, a second-order disturbance observer is designed to estimate the disturbance and their derivatives.. After this, combining with the second-order disturbance observer, a modified sliding surface and the corresponding reaching law are designed to obtain the rudder deflection command directly. Thus, the real sense of IGC system is achieved. Next, the paper uses the Lyapunov stability theory to prove the stability of the system. Finally, the paper provides different simulation cases, which have different maneuver modes of the target, to demonstrate the superiority of the proposed method in reducing the response time, increasing the rudder response, and having a high interception probability.

Radostina Petkova, Vladimir Poulkov, Agata Manolova et al.

Holographic-type communication (HTC) permits new levels of engagement between remote users. It is anticipated that it will give a very immersive experience while enhancing the sense of spatial co-presence. In addition to the newly revealed advantages, however, stringent system requirements are imposed, such as multi-sensory and multi-dimensional data capture and reproduction, ultra-lightweight processing, ultra-low-latency transmission, realistic avatar embodiment conveying gestures and facial expressions, support for an arbitrary number of participants, etc. In this paper, we review the current limitations to the HTC system implementation and systemize the main challenges into a few major groups. Furthermore, we propose a conceptual framework for the realization of an HTC system that will guarantee the desired low-latency transmission, lightweight processing, and ease of scalability, all accompanied with a higher level of realism in human body appearance and dynamics.

Dusty R. Miller, Ethan S. McClain, James N. Dodds et al.

Despite the significant progress in both scientific understanding and regulations, the safety of agricultural pesticides continues to be called into question. The need for complementary analytics to identify dysregulation events associated with chemical exposure and leverage this information to predict biological responses remains. Here, we present a platform that combines a model organ-on-chip neurovascular unit (NVU) with targeted mass spectrometry (MS) and electrochemical analysis to assess the impact of organophosphate (OP) exposure on blood-brain barrier (BBB) function. Using the NVU to simulate exposure, an escalating dose of the organophosphate chlorpyrifos (CPF) was administered. With up to 10 μM, neither CPF nor its metabolites were detected across the BBB (limit of quantitation 0.1 µM). At 30 µM CPF and above, targeted MS detected the main urinary metabolite, trichloropyridinol (TCP), across the BBB (0.025 µM) and no other metabolites. In the vascular chamber where CPF was directly applied, two primary metabolites of CPF, TCP and diethylthiophosphate (DETP), were both detected (0.1–5.7 µM). In a second experiment, a constant dose of 10 µM CPF was administered to the NVU, and though neither CPF nor its metabolites were detected across the BBB after 24 h, electrochemical analysis detected increases in acetylcholine levels on both sides of the BBB (up to 24.8 ± 3.4 µM) and these levels remained high over the course of treatment. In the vascular chamber where CPF was directly applied, only TCP was detected (ranging from 0.06 μM at 2 h to 0.19 μM at 24 h). These results provide chemical evidence of the substantial disruption induced by this widely used commercial pesticide. This work reinforces previously observed OP metabolism and mechanisms of impact, validates the use of the NVU for OP toxicology testing, and provides a model platform for analyzing these organotypic systems.

Chao Fan, Zhenyu Yin, Fulong Xu et al.

In recent years, self-supervised monocular depth estimation has gained popularity among researchers because it uses only a single camera at a much lower cost than the direct use of laser sensors to acquire depth. Although monocular self-supervised methods can obtain dense depths, the estimation accuracy needs to be further improved for better applications in scenarios such as autonomous driving and robot perception. In this paper, we innovatively combine soft attention and hard attention with two new ideas to improve self-supervised monocular depth estimation: (1) a soft attention module and (2) a hard attention strategy. We integrate the soft attention module in the model architecture to enhance feature extraction in both spatial and channel dimensions, adding only a small number of parameters. Unlike traditional fusion approaches, we use the hard attention strategy to enhance the fusion of generated multi-scale depth predictions. Further experiments demonstrate that our method can achieve the best self-supervised performance both on the standard KITTI benchmark and the Make3D dataset.

Zongrui Tong, Yong Gao, Huang Yang et al.

Abstract Catalytic therapy utilizing special substances (e.g., hydrogen peroxide and glucose) in tumor sites has attracted wide interest to achieve tumor‐specific therapy or improve the efficacy of other treatments. Benefiting from the selectivity and high activity of catalytic chemistry, efficient cancer therapy is available with negligible side effects. Numerous works, which are focused on further augmenting catalytic therapy with cascade strategies, have been reported with biocompatible nanomaterials composed of natural enzymes and/or nanozymes. Herein, we summarized catalytic reactions and nanomaterials in cascade strategy‐involved cancer therapy. With rapid advances in chemistry and nanomaterials, developing more selective and efficient cascade catalytic strategies will continue to be promising and challenging for cancer therapy.

Xiao-qiang Cao, Fei Xiao, Xiao-yu Xie et al.

Functional magnetic Fe3O4@PPy microspheres were prepared and characterized by XRD, FTIR, SEM, TEM, and magnetometer, and the adsorption of Hg(II) onto Fe3O4@PPy was investigated. The results showed that the adsorption of Hg(II) onto Fe3O4@PPy dramatically increases within 5 min and reaches adsorption equilibrium at 200 min. The adsorption of Hg(II) increases with pH increased, and a removal efficiency (RE) of 90.5% was obtained at pH 7.2. The isotherm studies revealed that the adsorption of Hg(II) onto the Fe3O4@PPy fits well with the Langmuir isotherm model, and the calculated qm value of 232.56 mg/g. The adsorption process of Hg(II) onto the Fe3O4@PPy is well-fitted by the pseudo-second-order model with a high correlation coefficient (R2) of 0.999. The thermodynamic coefficients (ΔH°, ΔS°, and ΔG°) were calculated from the temperature-dependent adsorption isotherms and illustrated that the adsorption of Hg(II) on the Fe3O4@PPy was spontaneous and endothermic. Different desorption agents were used to recover Hg(II) adsorbed onto Fe3O4@PPy, and a satisfactory recovery percentage of 93.0% was obtained by using 0.1 M HCl and 0.05 M NaCl. HIGHLIGHTS Amino-functional magnetic Fe3O4@PPy microspheres were prepared and characterized.; The Hg(II) can be adsorbed by Fe3O4@PPy effectively.; The used Fe3O4@PPy could be regenerated by two-component desorbent of HCl and NaCl.;

Junling Gao, V. Oloibiri, M. Chys et al.

Hsien-Ming Lee, D. R. Larson, D. Lawrence

P. Sazio, A. Amezcua-Correa, C. Finlayson et al.

Sunggyu Lee, J. Speight, S. Loyalka

Thomas Provot, Xavier Chiementin, Emeric Oudin et al.

The musculo-skeletal response of athletes to various activities during training exercises has become a critical issue in order to optimize their performance and minimize injuries. However, dynamic and kinematic measures of an athlete’s activity are generally limited by constraints in data collection and technology. Thus, the choice of reliable and accurate sensors is crucial for gathering data in indoor and outdoor conditions. The aim of this study is to validate the use of the accelerometer of a high sampling rate ( 1344 Hz ) Inertial Measurement Unit (IMU) in the frame of running activities. To this end, two validation protocols are imposed: a classical one on a shaker, followed by another one during running, the IMU being attached to a test subject. For each protocol, the response of the IMU Accelerometer (IMUA) is compared to a calibrated industrial accelerometer, considered as the gold standard for dynamic and kinematic data collection. The repeatability, impact of signal frequency and amplitude (on shaker) as well as the influence of speed (while running) are investigated. Results reveal that the IMUA exhibits good repeatability. Coefficient of Variation CV is 1 % 8.58 ± 0.06 m / s 2 on the shaker and 3 % 26.65 ± 0.69 m / s 2 while running. However, the shaker test shows that the IMUA is affected by the signal frequency (error exceeds 10 % beyond 80 Hz ), an observation confirmed by the running test. Nevertheless, the IMUA provides a reliable measure in the range 0–100 Hz, i.e., the most relevant part in the energy spectrum over the range 0–150 Hz during running. In our view, these findings emphasize the validity of IMUs for the measurement of acceleration during running.