Search Results (17)

To enhance the accuracy and efficiency of controlled fault current interruption (CFI) in short-circuit current processing within power systems, a half-cycle elimination prediction algorithm and a double-sampling CFI sequence method are proposed in this study. By analyzing the non-periodic and periodic components of short-circuit currents, the half-cycle elimination method and fast Fourier transform are utilized to compute these two components, respectively. The double-sampling CFI sequence approach is designed to fully utilize the response and waiting times of relay protection. Following the first sampling to estimate the target zero-crossing point, the remaining response and waiting times are allocated for a second sampling and recalculation to enhance the precision of zero-crossing prediction. MATLAB R2023a is employed to conduct multi-scenario simulations, and the algorithm’s performance is evaluated using actual recorded waveform data. The results demonstrate that the proposed algorithm accurately predicts the target zero-crossing point after a short circuit, with a computational error of less than 0.2 ms. Furthermore, the double-sampling sequence method is shown to improve the accuracy of open-circuit zero-crossing point calculations by an order of magnitude. This work provides a novel technical approach for the fast and precise handling of short-circuit faults in power systems. Full article

Background: Exogenous melatonin, a nutraceutical for maintaining a healthy sleep–wake cycle and managing sleep disorders, requires large, repeated doses due to its low bioavailability and short half-life. This necessitates the development of a sustained-release formulation with a longer half-life and sustained plasma concentration. Therefore, exogenous novel 5 mg sustained-release melatonin capsules (Melatonin-SR, test product) were formulated. Methods: This open-label cross-over study compared the pharmacokinetics (maximum concentration [C_max], time to reach C_max [T_max], area under the curve [AUC], and elimination half-life [t_1/2]) and the safety of Melatonin-SR with 5 mg immediate-release melatonin capsules (Melatonin-IR, reference product) after single-dose oral administration in healthy fasting adults. Results: Sixteen participants (aged 18–45 years) were randomized (1:1) to receive either Melatonin-SR or Melatonin-IR in two periods with a 7-day washout period. Melatonin-SR reported a lower C_max (11,446.87 pg/mL) compared to Melatonin-IR (22,786.30 pg/mL). The mean T_max of Melatonin-SR and Melatonin-IR was 1.26 h and 0.87 h, respectively. The mean t_1/2 of Melatonin-SR (5.10 h) was prolonged by five-fold compared to Melatonin-IR (1.01 h). One adverse event (vomiting) was reported following the administration of the Melatonin-IR. Conclusions: Melatonin-SR resulted in higher and sustained plasma melatonin concentrations for an extended period and was well-tolerated. Hence, Melatonin-SR may be a promising nutraceutical for maintaining healthy sleep. Full article

Cannabidiol (CBD) has multiple therapeutic benefits that need to be maximized by optimizing its bioavailability. Numerous formulations are therefore being developed and their pharmacokinetics need to be studied, requiring analytical methods and data from intravenous administration. As CBD is susceptible to hepatic metabolism, the requirement of any method is to quantify metabolites such as 7-COOH-CBD. We demonstrated that CBD and 7-COOH-CBD could be simultaneously and correctly quantified in piglet plasma by using an UHPLC–MS/MS technique. The validated method allowed for an accurate bioanalysis of an intravenously injected solution consisting of CBD-HPβCD complexes. The experimental pharmacokinetic profile of CBD showed multi-exponential decay characterized by a fast apparent distribution half-life (0.25 h) and an elimination half-life of two hours. The profile of 7-COOH-CBD was not linked with the first-pass metabolism, since 80% of the maximum metabolite concentration was reached at the first sampling time point, without any decrease during the period of study. A two-compartment model was optimal to describe the experimental CBD profile. This model allowed us to calculate macro–micro constants and volumes of distribution (V_ss = 3260.35 ± 2286.66 mL) and clearance (1514.5 ± 261.16 mL·h⁻¹), showing that CBD is rapidly distributed to peripheral tissues once injected and slowly released into the bloodstream. Full article

This study proposes an integrated framework to automatically detect anomalies and faults in underground transmission-line connectors (UTLCs) with thermal images because anomaly detection of underground transmission-line connectors (UTLCs) plays a critical role in power line risk management. The proposed framework features three key characteristics. First, the measured thermal images were preprocessed through z-score normalization and image strengthening. Z-score normalization improves the robustness of feature extraction for UTLCs even though noise exists in a thermal image, and image strengthening improves the accuracy of segmentation for UTLCs. Second, a preprocessed thermal image is segmented to detect UTLCs by addressing a multiscale mask deep convolutional neural network (MS mask DCNN). The MS mask DCNN effectively detects UTLCs, enabling anomaly detection only for pixels of UTLCs. Specifically, the multiscale feature extraction module enables the extraction of distinct features of UTLCs and environments, and the skip-layer fusion module concatenates distinct features from the feature extraction module. Furthermore, a half tensor is used to reduce computational resources but maintain the same segmentation accuracy, enhancing the feasibility of the proposed framework in field applications. Third, anomaly detection is performed by addressing the contour method and unsupervised clustering method of DBSCAN. The contour method compensates for the limits of the MS mask DCNN for real-world applications because the neural networks cannot secure perfect accuracy of 100% owing to a lack of sufficient training images and low computational resources. DBSCAN improves the accuracy of diagnosis and ensures robustness to eliminate noise from thermal reflection caused by low-emissivity objects. Field experiments with high-voltage UTLCs demonstrated the effectiveness of the proposed framework. Ablation studies also confirmed that the methods addressed in this study outperform other methods. The proposed framework with a novel automatic non-destructive patrol inspection system would decrease the risks of human casualties during the periodic operation and maintenance of UTLCs, which are currently the most critical concerns. Full article

To reduce carbon dioxide emissions from traditional drying methods, this research investigated the use of microwave technology for drying Standard Thai Rubber (STR) in Thailand. Commercial microwave ovens were modified and integrated with the microwave emitting power control system to maintain the appropriate temperature levels to evaporate the moisture from rubber. Throughout the drying process, the temperature of the rubber was measured both internally and outside. The results revealed that STR5L and STR20 could be dried satisfactorily and met the requirements for standard Thai rubber properties by utilizing 500 W for 140 and 120 min, respectively. By keeping the temperatures less than 150 °C, rubbers’ molecular structure is not destroyed from internal heat stress. Although utilizing less power for a longer period of time is possible, more energy was used, which is unfavorable. Compared to traditional hot air drying technologies, which take approximately 4–6 h for the drying process, microwave technology potentially reduces the drying time by half or more. If solar energy is used to supply electrical energy, 300,000 tons of Carbon dioxide can potentially be eliminated annually in the STR drying industry in Thailand by promoting approximately 1115 MW of Photovoltaic technology installations with the solar resources in southern Thailand. Full article

Oxypeucedanin, a furanocoumarin extracted from many traditional Chinese herbal medicines, has a variety of pharmacological effects. However, the independent pharmacokinetic characteristics and bioavailability of this compound remains elusive. In this study, a rapid, sensitive, and selective method using ultra-high performance liquid chromatography–tandem mass spectrometry (UPLC/MS/MS) was developed for evaluating the intravenous and oral pharmacokinetics of oxypeucedanin. After intravenous administration of oxypeucedanin (2.5, 5, and 10 mg/kg), and intragastric administration of oxypeucedanin (20 mg/kg), blood samples were collected periodically from the tail vein. The plasma concentration-time curves were plotted, and the pharmacokinetic parameters were calculated using a non-compartmental model analysis. After intravenous administration of oxypeucedanin (single dosing at 2.5, 5, and 10 mg/kg) to rats, the pharmacokinetics fit the linear kinetics characteristics, which showed that some parameters including average elimination half-life (T_1/2Z of 0.61~0.66 h), mean residence time (MRT of 0.62~0.80 h), apparent volume of distribution (V_Z of 4.98~7.50 L/kg), and systemic clearance (CL_Z of 5.64~8.55 L/kg/h) are dose-independent and the area under concentration-time curve (AUC) increased in a dose-proportional manner. Single oral administration of oxypeucedanin (20 mg/kg) showed poor and slow absorption with the mean time to reach the peak concentration (T_max) of 3.38 h, MRT of 5.86 h, T_1/2Z of 2.94 h, and a mean absolute bioavailability of 10.26% in rats. These results provide critical information for a better understanding of the pharmacological effect of oxypeucedanin, which will facilitate its research and development. Full article

Numerous attempts to overcome the poor water solubility of cam ptothecin (CPT) by various nano drug delivery systems are described in various sources in the literature. However, the results of these approaches may be hampered by the incomplete separation of free CPT from the formulations, and this issue has not been investigated in detail. This study aimed to promote the solubility and continuous delivery of CPT by developing long-lasting liposomes using various weights (M.W. 2000 and 5000 Daltons) of the hydrophilic polymer polyethylene glycol (PEG). Conventional and PEGylated liposomes containing CPT were formulated via the lipid film hydration method (solvent evaporation) using a rotary flash evaporator after optimising various formulation parameters. The following physicochemical characteristics were investigated: surface morphology, particle size, encapsulation efficiency, in vitro release, and formulation stability. Different molecular weights of PEG were used to improve the encapsulation efficiency and particle size. The stealth liposomes prepared with PEG₅₀₀₀ were discrete in shape and with a higher encapsulation efficiency (83 ± 0.4%) and a prolonged rate of drug release (32.2% in 9 h) compared with conventional liposomes (64.8 ± 0.8% and 52.4%, respectively) and stealth liposomes containing PEG₂₀₀₀ (79.00 ± 0.4% and 45.3%, respectively). Furthermore, the stealth liposomes prepared with PEG₅₀₀₀ were highly stable at refrigeration temperature. Significant changes were observed using various pharmacokinetic parameters (mean residence time (MRT), half-life, elimination rate, volume of distribution, clearance, and area under the curve) of stealth liposomes containing PEG₂₀₀₀ and PEG₅₀₀₀ compared with conventional liposomes. The stealth liposomes prepared with PEG₅₀₀₀ showed promising results with a slow rate of release over a long period compared with conventional liposomes and liposomes prepared with PEG₂₀₀₀, with altered tissue distribution and pharmacokinetic parameters. Full article

The end force of North-South permanent magnet linear synchronous motor (NS-PMLSM) fluctuates symmetrically with a period of one pole. Different from it, the end force’s fluctuation cycle of the consequent-pole permanent magnet linear synchronous motor (CP-PMLSM) is usually two poles and asymmetrical. Especially, within two half cycles, the end force presents complex asymmetric characteristics. In this paper, a piecewise function model of the end force of CP-PMLSM is established. Then a primary segmented design method for adjusting the period, symmetry and phase of the end force waveform is proposed. The two-segment and grouped four-segment modular distances are combined and matched to eliminate the odd-numbered harmonics of the end force and suppress the thrust ripple. A slotless primary core experimental platform and a slotted CP-PMLSM prototype are manufactured and tested to verify the theoretical analysis and simulation results. Full article

A high-performance gel permeation chromatography fluorescence detection (HPGPC-FD) method combined with fluorescein isothiocyanate (FITC) labeling was established for the microanalysis of L. barbarum polysaccharides (LBP). The calibration curves linear over the range of 0.2–20 µg/mL in rat plasma, and 0.25–500 μg/mL in urine and feces samples with correlation coefficients greater than 0.99. The inter-day and intra-day precisions (RSD, %) of the method were under 15% with the relative recovery ranging from 84.6% to 104.0% and the RSD ranging from 0.47% to 7.28%. The concentration–time curve of LBP-FITC in plasma following intragastric administration at 100, 50 and 25 mg/kg well fitted to a nonlinear model. LBP-FITC slowly eliminated from plasma according to the long half-lives (t_1/2 = 31.39, 38.09, and 45.76 h, respectively) and mean retention times (MRT_0–t = 18.38, 19.15 and 20.07 h, respectively; AUC_0–∞ = 230.49, 236.18 and 242.57 h, respectively) after administration of LBP-FITC at doses of 100, 50, and 25 mg/kg, respectively. After intragastric administration at 50 mg/kg for 72 h, the concentration of LBP-FITC in urine and feces was 0.09 ± 0.04% and 92.18 ± 3.61% respectively; the excretion rate of urine was the highest in 0–4 h period and decreased continuously in 4–24 h period. The excretion rate of feces was the highest in 4–10 h, 48.28 ± 9.349% in feces within 4–10 h, and decreased rapidly in 10–24 h. The present study showed that LBP was absorbed as its prototype and most proportion of LBP was excreted from feces, indicating a long time remaining in intestine. Full article

Road roughness is an important factor in road network maintenance and ride quality. This paper proposes a road-roughness estimation method using the frequency response function (FRF) of a vehicle. First, based on the motion equation of the vehicle and the time shift property of the Fourier transform, the vehicle FRF with respect to the displacements of vehicle–road contact points, which describes the relationship between the measured response and road roughness, is deduced and simplified. The key to road roughness estimation is the vehicle FRF, which can be estimated directly using the measured response and the designed shape of the road based on the least-squares method. To eliminate the singular data in the estimated FRF, the shape function method was employed to improve the local curve of the FRF. Moreover, the road roughness can be estimated online by combining the estimated roughness in the overlapping time periods. Finally, a half-car model was used to numerically validate the proposed methods of road roughness estimation. Driving tests of a vehicle passing over a known-sized hump were designed to estimate the vehicle FRF, and the simulated vehicle accelerations were taken as the measured responses considering a 5% Gaussian white noise. Based on the directly estimated vehicle FRF and updated FRF, the road roughness estimation, which considers the influence of the sensors and quantity of measured data at different vehicle speeds, is discussed and compared. The results show that road roughness can be estimated using the proposed method with acceptable accuracy and robustness. Full article

The aims of this study in goats were to determine the pharmacokinetics of doxycycline hyclate following single intravenous (IV), intramuscular (IM) and oral administrations of 20 mg/kg and to evaluate the pharmacokinetics and accumulation of doxycycline hyclate after repeated oral administrations at a 20 mg/kg dose every 24 h for 5 days. Six healthy male goats were used for the study. The study was performed in four periods according to a longitudinal study with a 15-day washout period. Plasma concentrations of doxycycline were determined using HPLC-UV and analyzed by a non-compartmental method. IM injection of doxycycline caused swelling and pain due to irritation in the injection site. After IM and oral administrations, terminal elimination half-life (t_1/2λz) and mean residence time (MRT) were prolonged and areas under the curve (AUCs) were low. The mean bioavailability of IM and oral administration was 51.51% and 31.39%, respectively. Following repeated oral administration, the accumulation ratio of doxycycline was 1.76. Pharmacokinetic properties including weak accumulation, wide distribution volume and long elimination half-life can make doxycycline hyclate valuable for repeated use via an oral route in the treatment of some infectious diseases in goats. However, the determination of pharmacodynamic effects on susceptible pathogens isolated from goats is also necessary to confirm the drug dosage regimen. Full article

Brain-derived neurotrophic factor (BDNF) is one of the key signaling molecules that supports the viability of neural cells in various brain pathologies, and can be considered a potential therapeutic agent. However, several methodological difficulties, such as overcoming the blood–brain barrier and the short half-life period, challenge the potential use of BDNF in clinical practice. Gene therapy could overcome these limitations. Investigating the influence of viral vectors on the neural network level is of particular interest because viral overexpression affects different aspects of cell metabolism and interactions between neurons. The present work aimed to investigate the influence of the adeno-associated virus (AAV)-Syn-BDNF-EGFP virus construct on neural network activity parameters in an acute hypobaric hypoxia model in vitro. Materials and methods. An adeno-associated virus vector carrying the BDNF gene was constructed using the following plasmids: AAV-Syn-EGFP, pDP5, DJvector, and pHelper. The developed virus vector was then tested on primary hippocampal cultures obtained from C57BL/6 mouse embryos (E18). Acute hypobaric hypoxia was induced on day 21 in vitro. Spontaneous bioelectrical and calcium activity of neural networks in primary cultures and viability tests were analysed during normoxia and during the posthypoxic period. Results. BDNF overexpression by AAV-Syn-BDNF-EGFP does not affect cell viability or the main parameters of spontaneous bioelectrical activity in normoxia. Application of the developed virus construct partially eliminates the negative hypoxic consequences by preserving cell viability and maintaining spontaneous bioelectrical activity in the cultures. Moreover, the internal functional structure, including the activation pattern of network bursts, the number of hubs, and the number of connections within network elements, is also partially preserved. BDNF overexpression prevents a decrease in the number of cells exhibiting calcium activity and maintains the frequency of calcium oscillations. Conclusion. This study revealed the pronounced antihypoxic and neuroprotective effects of AAV-Syn-BDNF-EGFP virus transduction in an acute normobaric hypoxia model. Full article

The pharmacokinetics of salicylic acid (SA) in sheep was evaluated following intravenous (IV) and oral administration of sodium salicylate (sodium salt of salicylic acid) at different doses. Six healthy sheep were administered sodium salicylate (SS) IV at doses of 10, 50, 100 and 200 mg/kg body weight and another six sheep were drenched with 100 and 200 mg/kg of SS orally. Both studies were randomised crossover trials. A one-week washout period between each treatment was allowed in both studies. Blood samples were collected at 0, 15, 30 min and 1, 2, 4 and 6 h after IV and oral SS administrations. Plasma SA concentrations were determined using high-performance liquid chromatography (HPLC) with diode array detection method. Pharmacokinetic variables were calculated in a non-compartmental model. The elimination half-life (T_{1/2 el}) of SA after IV administration of 200 mg/kg SS was 1.16 ± 0.32 h. Mean bioavailability of SA was 64%, and mean T_{1/2 el} was 1.90 ± 0.35 h, after 200 mg/kg of oral SS. The minimum plasma SA concentration (16.8 µg/mL) reported to produce analgesia in humans was achieved after IV administration of 100 and 200 mg/kg SS in sheep for about 0.17 h in this study. Experiments on pharmacokinetic–pharmacodynamics modelling are required to determine the actual effective plasma concentration range of SA in sheep. Full article

As a promising technology to improve shale gas (SG) recovery and CO₂ storage capacity, the multi-well pads (MWPs) scheme has gained more and more attention. The semi-analytical pressure-buildup method has been used to estimate CO₂ storage capacity. It focuses on single multi-fractured horizontal wells (SMFHWs) and does not consider multi-well pressure interference (MWPI) induced by the MWPs scheme. This severely limits the application of this method as incidences of multi-well pressure interference have been widely reported. This paper proposed a new methodology to optimize the injection strategy of the MWPs scheme and maximize CO₂ storage capacity. The new method implements numerical discretization, the superposition theory, Gauss elimination, and the Stehfest numerical algorithm to obtain pressure-buildup solutions for the MWPs scheme. The solution by the new method was validated with numerical simulation and pressure-buildup curves were generated to identify MWPI. Using the new method, we observed that the fracture number and fracture half-length have a positive influence on CO₂ storage capacity. Both can be approximately related to the CO₂ storage capacity by a linear correlation. For a given injection pressure, there is an optimal fracture number; the bigger the limited injection pressure, the smaller the optimal fracture number. Stress sensitivity has positive influences on CO₂ storage capacity, thus extending the injection period would improve CO₂ storage capacity. This work gains some insights into the CO₂ storage capacity of the MWPs scheme in depleted SG reservoirs, and provides considerable guidance on injection strategies to maximize CO₂ storage capacity in depleted SG reservoirs. Full article

In traditional oriental medicine, Angelica dahurica Radix (ADR) is used in the treatment of gastrointestinal, respiratory, neuromuscular, and dermal disorders. We evaluated the pharmacokinetic profiles of oxypeucedanin, imperatorin, and isoimperatorin, major active ingredients of ADR, in normal and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rats. A rapid, sensitive, and validated UPLC/MS/MS method was established for evaluating the pharmacokinetics of three furanocoumarins. After oral administration of ADR (0.5 and 1.0 g/kg), blood samples were collected periodically from the tail vein. In colitis rats, the time to reach the peak concentration (T_max) of imperatorin and isoimperatorin was significantly delayed (p < 0.05). Lower peak plasma concentrations (C_max) and longer mean residence times for all furanocoumarins were also observed (p < 0.05) compared with normal rats. There was no significant difference in the area under the plasma concentration–time curve or elimination half-lives. Thus, the delayed T_max and decreased C_max, with no influence on the elimination half-life, could be colitis-related changes in the drug-absorption phase. Therefore, the prescription and use of ADR in colitis patients should receive more attention. Full article