Search Results (119)

Background and Objectives: Functional decline is a major determinant of disability, caregiver burden, and loss of independence in behavioral variant frontotemporal dementia (bvFTD). Although bvFTD is characterized by early and rapidly progressive deterioration in everyday functioning, the multimodal contributors associated with longitudinal functional change remain insufficiently understood. The present study aimed to identify the strongest cognitive, behavioral, personality, and neuroimaging correlates of longitudinal functional deterioration in bvFTD using an integrated multimodal framework over a 12-month follow-up period. Methods: Twenty-seven patients diagnosed with bvFTD were recruited from the 2nd Neurology Clinic of the “AHEPA” University Hospital in Thessaloniki, Greece, and underwent comprehensive face-to-face neuropsychological assessment for the evaluation of a wide range of cognitive domains, alongside caregiver-based evaluations of behavioral disturbances, personality changes, and functional abilities, at baseline, 6 months, and 12 months. Brain perfusion single-photon emission computed tomography (SPECT) was acquired only at baseline, with regional cerebral blood flow (rCBF) quantified using a Brodmann area (BA)-based approach. Functional status was assessed using the Disability Assessment for Dementia (DAD) as the primary outcome, while the Frontotemporal Dementia Rating Scale (FRS) served as a secondary measure. Repeated-measures analysis of variance (ANOVA) was used to characterize longitudinal changes across cognitive, behavioral, personality, and functional domains, while linear mixed-effects (LME) models were applied to identify longitudinal correlates of functional decline and sources of inter-individual variability in functional outcomes. Results: Significant progressive decline in functional abilities was observed over the 1-year follow-up period, consistent with an aggressive and rapidly deteriorating clinical course in bvFTD. Reductions in functional performance were evident across both basic and instrumental activities of daily living, with deterioration being more pronounced in instrumental activities. Based on the final LME model, greater apathy-related (negative) behavioral symptoms, global cognitive impairment, attentional and processing speed deficits, and impaired inhibitory control were independently associated with poorer longitudinal functional outcomes (p < 0.001). At the neuroimaging level, reduced baseline perfusion in the right BA 24 within the anterior cingulate cortex was also significantly associated with greater loss of functional independence over time (p < 0.001). Conclusions: Longitudinal functional decline in bvFTD reflects the combined disruption of behavioral regulation, global cognition, executive control, and frontal–cingulate network integrity. The findings provide a preliminary foundation for future research investigating factors associated with accelerated functional decline. Further validation in larger, multicenter longitudinal cohorts is needed to determine the prognostic relevance of these factors and their potential applicability to patient stratification and individualized care planning. Full article

Severe fracturing-fluid retention and low post-fracturing flowback efficiency are common in the Lianggaoshan shale reservoirs of the Sichuan Basin. Liquid loading may also occur during late production. To address these problems, this study investigates a synergistic flowback technology that combines natural fracturing-fluid flowback with CO₂ gas lift. First, based on the complex fracture network characteristics of the Lianggaoshan shale reservoir, the interaction mechanisms between hydraulic fractures and natural fractures were investigated. An energy model for fracturing-fluid flowback under natural flowback conditions was established, revealing that reservoir gas expansion energy, hydromechanical energy, and rock elastic energy are the primary driving forces for fracturing-fluid flowback. Furthermore, considering fracture closure behavior, fluid leakoff, and wellbore flow dynamics, a calculation model for the natural flowback of fracturing fluid was developed, and a staged pressure-controlled flowback strategy was proposed. Subsequently, to address the decline in liquid unloading capacity caused by formation-energy depletion during the late stage of natural flowback, a gas-lift-assisted flowback multiphase flow model for the wellbore was established. The effects of the gas injection pressure, gas injection rate, and wellhead pressure on liquid unloading efficiency were systematically investigated. The results indicate that the liquid unloading rate increases with an increasing gas injection pressure and gas injection rate; however, a pronounced diminishing marginal effect is observed. For the Well H1 reference case, the central recommended gas injection pressure was 12 MPa, the gas injection rate was 8 × 10⁴–10 × 10⁴ m³/d, and the wellhead backpressure was maintained below 0.5 MPa. Furthermore, the CO₂-assisted flowback mechanisms were evaluated by distinguishing between the effects explicitly represented in the model and the potential reservoir-scale physicochemical effects. The reduction in wellbore mixture density and bottomhole flowing pressure was simulated directly, whereas CO₂–oil mass transfer, viscosity reduction, mineral dissolution, and changes in water-blocking behavior were interpreted with reference to published experimental studies. Based on these mechanisms, a three-stage synergistic optimized flowback scheme, consisting of “CO₂ soaking–natural flowback–CO₂ gas lift,” was established. A sequence of stagewise quasi-steady PIPESIM calculations was subsequently performed over the 30-day operating schedule. Under the adopted simulation conditions, the recommended soaking period is 5–7 days. The operation should be switched to gas lift when the wellhead pressure falls below 1.5 MPa or when daily liquid production declines continuously by more than 20%. Under the synergistic scheme, the 30-day cumulative flowback volume was predicted to reach 3492 m³. This value was substantially higher than those obtained by conventional natural flowback and standalone gas-lift processes. Moreover, the flowback curve exhibits a distinct “secondary surge” characteristic. These findings provide a theoretical basis and technical support for efficient fracturing-fluid flowback and stable long-term production in the Lianggaoshan Formation. They may also be applicable to other shale oil reservoirs with low porosity and ultra-low permeability. Full article

The rapid development of wind and solar energy necessitates a solution to the problem of the optimal spatial placement of wind farms (WFs) and solar farms (SFs) within electric power systems. The non-stationary generation schedules of WFs and SFs place increased demands on the flexibility of conventional generation, determined by the intensity of net load fluctuations. This paper proposes a methodology for the spatial optimization of WF and SF location, in which the optimization criteria include net load indicators (rate of net load change and net load increment), the base power of the RES system, and the economic criterion of maximum electricity generation. Unlike existing approaches, in which the geographical smoothing effect on power fluctuations is treated as an incidental outcome, the proposed methodology employs it as an explicit optimization criterion for RES placement. The algorithm provides for the preliminary ranking of candidate sites based on the maximum electricity generation criterion, followed by the redistribution of generating capacities among sites with an acceptable capacity factor in accordance with the selected optimization criterion. The methodology was tested on a model comprising six potential wind farm sites and two solar farm sites with a total installed capacity of 600 MW and a maximum power system load of 3000 MW. The obtained results show that the optimal redistribution of installed capacities among sites allows a 31.5% reduction in net load variability intensity to be achieved with an 11.6% reduction in electricity generation relative to the maximum possible. The study is based on idealized daily generation and consumption profiles and is theoretical in nature, proposing a pre-screening tool for RES siting that complements rather than replaces subsequent network-constrained planning studies, including power-flow analysis and grid verification, and establishes a methodological foundation for further development using real multi-year retrospective data. Full article

This paper develops a novel coupled model to predict the thermal behavior of a high-temperature fast heat storage unit, integrating Power-to-Heat technology with steam generation. A phase change material (PCM) made of a ZnAl₆ metal alloy is used for heat storage. Electricity is used to charge the battery, and the stored energy is used to produce superheated steam during discharge. The coupled model was based on a 3D multiphase CFD model of the heat storage unit and a 1D multiphase water boiling model implemented in Python language. The CFD model solves the transient conservation equations of mass, momentum, and energy using the enthalpy–porosity method to describe phase change, while heat transfer to water is represented by a coupled 1D boiling model. The paper also presents a preliminary design, a computational strategy, and boundary conditions for the operating modes, providing an analytical foundation for detailed engineering, production, and implementation in real-world industrial environments. The presented results confirmed the correct operation of the model and enabled the evaluation of system performance, discharge behavior, and validation of the geometric assumptions required to achieve the target steam parameters. The proposed modular design allows for system scalability, while the entire system is a response to the daily variability of electricity prices resulting from periodic reductions in demand and overproduction of electricity from renewable sources. Estimated thermal behavior of the thermal storage unit for the discharging scenario allows reaching constant output power at the level of 200 kW for 85 min. Integration with a cooling reduction station allows constant system power output to be maintained by increasing the mass flow rate as the steam parameters decrease from over 400 °C to 200 °C with a lowering state of charge. Full article

Background and purpose: Short-term external counterpulsation (ECP) noninvasively augments cerebral blood flow by elevating blood pressure in ischemic stroke. The current retrospective case–control study examined the effect of long-term ECP treatment on blood pressure and beat-to-beat blood pressure variability (BPV) in patients with recent ischemic stroke. Method: The ECP group included data from 20 recent ischemic stroke patients who received five daily 1 h sessions each week for seven weeks, for a total of 35 sessions of ECP treatment from our ECP registry. An equivalent comparative control group without ECP treatment was composed from the same pool of patients and matched with cases by sex and age. Beat-to-beat heart rate and blood pressure were monitored before and after the long-term intervention. Power spectral analysis calculated the beat-to-beat BPV oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04–0.15 Hz), high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio. Result: There was a significant reduction in systolic blood pressure (SBP) after the intervention compared with that before intervention in both groups (p < 0.05), but only the ECP group displayed a statistically significant reduction in diastolic blood pressure (DBP) (p = 0.023). The changes in SBP and DBP (delta SBP and delta DBP) from pre-intervention to completion showed no significant differences between the two groups (all p > 0.05). The ECP group exhibited a more pronounced and significant decrease in each spectral component of BPV after the intervention than at pre-intervention, with a substantial decrease in systolic BPV at TP (p = 0.048) and in the LF/HF ratios (p = 0.021 in diastolic BPV and p = 0.004 in systolic BPV, respectively) compared to the control group. Conclusions: A standard 35-session ECP treatment decreases beat-to-beat BPV but does not change SBP and DBP in patients with recent ischemic stroke. This implies that long-term ECP treatment may enhance autonomic regulation to benefit post-stroke clinical outcomes. Full article

Background: COVID-19 can have adverse effects on individuals’ lung functions for up to 6 months or more after the episode. As a result, people may be reluctant to exercise, and this can have further adverse effects on their lung capacity and fitness. This study aimed to examine the effectiveness of a telemedicine program designed to increase the exercise participation of young adults after COVID-19 and evaluate the changes in lung function after exercise training. Methods: The quasi-experimental pre–post study recruited sixty university students who had suffered from COVID-19 within the past 12 months. Four pulmonary outcomes were compared: forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR), and the ratio of FEV1 to FVC. The telemedicine exercise (TE) group (n = 36) received an intervention to carry out regular stepping exercise (up to 10,000 steps) via online video instruction and frequent WhatsApp reminder messages. The control group (n = 24) only received an initial WhatsApp message to carry out regular stepping exercise, with no further follow-up. Results: The FVC, FEV1, and FEV1/FVC ratio revealed significant overall improvement both within groups and between groups (p < 0.001), with moderate effect sizes. PEFR showed a significant improvement within groups (p = 0.007) but not between groups (p = 0.533). The TE group recorded a significant increase in daily step count (from 7165 to 9733, p < 0.001) after 4 weeks of training. The control group showed a significant reduction in step count (from 6975 to 6442, p = 0.049). Conclusions: The results confirmed the beneficial effects of the telemedicine exercise program in contributing to increased exercise participation and improved lung functions. Full article

Global climate change and spatiotemporal heterogeneity in water resources exacerbate supply-demand imbalances. Accurate outflow simulation for joint reservoir group operations thus becomes critical for scientific water resources management. Existing data-driven models like the Long Short-Term Memory (LSTM) lack the robust integration of physical constraints. Traditional mechanistic methods, by contrast, lack generality and stability under complex hydrological conditions. To address this limitation, we propose MDUPLEX-KG-LSTM—a physically constrained data-driven model for reservoir outflow simulation. The model incorporates multi-round DUPLEX (MDUPLEX) data partitioning, which ensures statistical homogeneity across training, validation, and test datasets. It also features a Knowledge-Guided (KG) loss function that embeds core physical constraints: water balance, dead water level, flood season restricted water level, and inter-reservoir re-regulation mechanisms. Additionally, it adopts an LSTM network optimized via Particle Swarm Optimization (PSO) for enhanced predictive performance. We validate the model using daily hydrological data from 2010 to 2025 for three reservoirs in the Wujiaqu Irrigation District of Xinjiang, China. The model exhibits exceptional stability and predictive accuracy across key evaluation metrics: Nash–Sutcliffe Efficiency (NSE) ≥ 0.82, Pearson correlation coefficient (r) > 0.94, Root Mean Square Error (RMSE) ≤ 1.50 m³/s, and Water Balance Index (WBI) ≤ 0.016. It outperforms conventional data-driven and mechanistic models in extreme flow simulation scenarios. It also eliminates unphysical negative outflow values in all predictive results. The model achieves 100% compliance with flood control standards and an irrigation guarantee rate of no less than 86%. This study advances the development of physically constrained data-driven modeling for water resources engineering. It provides reliable methodological support for the intelligent operation of reservoir groups in smart water conservancy systems. The model also balances training cost and inference efficiency effectively. It demonstrates verified scalability for reservoir groups of varying scales, fully meeting the operational deployment requirements of smart water systems. Full article

Background: Adipose tissue is a crucial endocrine organ, and obesity, due to its associated chronic inflammation and oxidative stress, disrupts adipokine secretion. These adipokines can be detected not only in blood but also in saliva. Dietary changes are a crucial part of managing obesity, encompassing a balanced diet, increased physical activity, and lifestyle modifications. Moreover, adding functional foods like amaranth and canola oils, recognized for their health benefits, may further improve metabolic and inflammatory health. These products have anti-inflammatory effects and may help reduce the pro-inflammatory activity of adipose tissue, thereby improving systemic and oral health. The study aimed to assess the impact of a 3-week calorie-restricted diet, supplemented with canola or amaranth oil on salivary adipokines, i.e., serpin A12, plasminogen activator inhibitor-1 (PAI-1), and tumor necrosis factor receptor-1 (TNF-R1), pH, and salivary flow in obese patients. Methods: A total of 115 adults with obesity (BMI > 30 kg/m²) were enrolled and placed on a 3-week calorie-restricted diet. The study group (n = 44) received additional supplementation: 21 participants received 20 mL of canola oil daily, and 23 received 20 mL of amaranth oil. The control group (n = 71) followed the same calorie-restricted diet without oil supplementation. Non-stimulated saliva was collected twice, for 20 min each time, before and after the intervention, to evaluate flow rate, pH, and concentrations of serpin A12, PAI-1, and TNF-R1. Concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Results: An increase in saliva flow rate was observed in patients supplemented with amaranth oil (p = 0.0367). Both the amaranth oil and canola oil groups showed a significant rise in salivary pH (p = 0.0425). Across all participants, the 3-week calorie-restricted diet resulted in a reduction in salivary PAI-1 (p = 0.0339), serpin A12 (p = 0.0001), and TNF-R1 (p = 0.0058). Conclusions: The 3-week calorie-restricted diet contributed to a decrease in the concentration of adipokines in saliva. The low-calorie diet, combined with supplementation of amaranth and canola oils, increased salivary flow and resulted in higher pH values, indicating greater alkalinity. Full article

The inverter is the key element that converts the intermittent DC power of the PV array into a quality AC flow to the grid and simultaneously performs functions such as power factor control, reactive services, and grid code compliance. Therefore, the detailed operating profile of the inverter, how the power, dynamics, power quality, and efficiency evolve over time, is critical for both the scientific understanding of the system and the daily operation (O&M). Monitoring only aggregated energy indicators or single KPIs (e.g., PR) is often insufficient: it does not distinguish weather-related variations from technical limitations (clipping, curtailment), does not show dynamic loads (ramp rate), and does not provide confidence in the quality of the injected energy (PF, P–Q behavior). These deficiencies motivate research that simultaneously covers the physical side of the conversion, the operational dynamics, and the climatic reference of the resource. The analysis covers the window of 25 January–15 April 2025 (winter→spring). Due to the pronounced seasonality of the solar resource and temperature regime, all quantitative results and conclusions regarding efficiency, dynamics, clipping, and degradation are valid only for this window; generalizations to other seasons require additional data. In the next stage, we will add ≥12 months of data and perform a comparable seasonal analysis. Full specifications of the measuring equipment (DC/AC current/voltage, clock synchronization, separate high-frequency $PQ$-logger) and quantitative uncertainty estimates, including distribution to key indicators ($\eta$, $PR$, $THD$, $I_{DC}$), are presented. The PVGIS per-kWp climate reference is anchored to the nameplate DC peak and cross-checked against percentile scaling; $a\pm \epsilon$ scale error shifts $PR$ by $\epsilon$ and changes $\Delta E$ proportionally only on hours with $\widehat{P}>P$. The capacity for the climate reference (PVGIS per-kWp) is calibrated to the tabulated DC peak power $C_{cert}$ and is cross-validated using a percentile scale ($Q_{0.99}$). Full article

Background/Objectives: Behavioral variant frontotemporal dementia (bvFTD), the most prevalent clinical subtype within the frontotemporal lobar degeneration spectrum disorders, is characterized by early and prominent changes that significantly disrupt everyday functioning. This study aims to identify the key correlates of functional status in bvFTD by investigating the relative contributions of cognitive deficits, behavioral disturbances, personality changes, and brain perfusion abnormalities. Additionally, it seeks to develop a theoretical framework to elucidate how these factors may interconnect and shape unique functional profiles. Methods: A total of 26 individuals diagnosed with bvFTD were recruited from the 2nd Neurology Clinic of “AHEPA” University Hospital in Thessaloniki, Greece, and underwent a comprehensive neuropsychological assessment to evaluate their cognitive functions. Behavioral disturbances, personality traits, and functional status were rated using informant-based measures. Regional cerebral blood flow was assessed using Single Photon Emission Computed Tomography (SPECT) imaging to evaluate brain perfusion patterns. Penalized Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was performed to identify the most robust correlates of functional impairment, followed by path analyses using structural equation modeling to explore how these factors may interrelate and contribute to functional disability. Results: The severity of negative behavioral symptoms (e.g., apathy), conscientiousness levels, and performance on neuropsychological measures of semantic verbal fluency, visual attention, visuomotor speed, and global cognition were identified as the strongest correlates of performance in activities of daily living. Neuroimaging analysis revealed hypoperfusion in the right prefrontal (Brodmann area 8) and inferior parietal (Brodmann area 40) cortices as statistically significant neural correlates of functional impairment in bvFTD. Path analyses indicated that reduced brain perfusion was associated with attentional and processing speed deficits, which were further linked to more severe negative behavioral symptoms. These behavioral disturbances were subsequently correlated with declines in global cognition and conscientiousness, which were ultimately associated with poorer daily functioning. Conclusions: Hypoperfusion in key prefrontal and parietal regions, along with the subsequent cognitive and neuropsychiatric manifestations, appears to be associated with the pronounced functional limitations observed in individuals with bvFTD, even in early stages. Understanding the key determinants of the disease can inform the development of more targeted, personalized treatment strategies aimed at mitigating functional deterioration and enhancing the quality of life for affected individuals. Full article

Objectives: Silodosin, a selective α1A-adrenoceptor antagonist, is used to treat lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). Genetic polymorphisms in drug-metabolizing enzymes and transporters may contribute to interindividual variability in its efficacy and safety. This study aimed to investigate the influence of CYP3A4, CYP3A5, UGT2B7, and ABCB1 polymorphisms on silodosin pharmacokinetics, efficacy, and safety in Russian patients with BPH. Methods: A prospective observational study included 103 Russian male patients with moderate-to-severe LUTS (IPSS > 8) due to BPH, treated with silodosin (8 mg daily) for 8 weeks. Genotyping for CYP3A4*1B, CYP3A4*22, CYP3A5*3, UGT2B7 (rs73823859, rs7439366, and rs7668282), and ABCB1 (rs4148738, rs1045642, rs2032582, and rs1128503) was performed using real-time PCR. The silodosin minimum steady-state plasma concentration (Css min) was measured via HPLC-MS. Efficacy was evaluated by the International Prostate Symptom Score (IPSS), quality of life scale, maximum urinary flow rate (Qmax), residual urine volume (RUV), and prostate volume at the baseline and week 8. Adverse drug reactions (ADRs) were recorded. Results: CYP3A4*22 CT carriers (n = 6) exhibited higher Css min (17.59 ± 2.98 vs. 9.0 ± 10.47 ng/mL, p = 0.049) but less absolute IPSS improvement (p < 0.05), likely due to higher baseline symptom severity. However, the change in IPSS (ΔIPSS_1–4) from the baseline to week 8 did not differ significantly (−5.78 ± 5.29 vs. −6.0 ± 4.54, p = 0.939). CYP3A5*3 GG homozygotes (n = 96) showed greater ΔIPSS_1–4 improvement (−6.25 ± 4.60 vs. 0.0 ± 9.53, p = 0.042) and a lower IPSS at day 28 (7.64 ± 4.50 vs. 20.0 ± 6.55, p < 0.001). UGT2B7 rs7439366 TT carriers (n = 34) had an improved Qmax (ΔQmax_1–4 5.4 vs. 3.3 and 2.0 mL/s for CC and CT, p = 0.041). ABCB1 1236C>T TT homozygotes (n = 25) showed a trend toward reduced RUV (p = 0.053). No polymorphisms were associated with adverse drug reactions (15 events in 42 patients, 35.7%). Conclusions: Genetic polymorphisms CYP3A4*22, CYP3A5*3, and UGT2B7 rs7439366 may modulate silodosin pharmacokinetics and efficacy parameters in BPH patients but not safety. Larger-scale studies are warranted to validate these initial findings. Full article

This paper describes a novel wearable personal uroflowmeter and its use to log urine leakage episodes in women. Consisting of a miniature flow rate sensor attached under the urethral meatus, it recorded both urine flow rate and volume during activities of daily living. The sensor communicated with a determining unit incorporating a microcontroller and an inertial measurement unit worn at the waist, facilitating the post-hoc determination of which activities and changes in pose caused leakage. Six women participated in a feasibility study performed in a clinical setting. The results indicate that the uroflowmeter was 97.5% accurate in assessing micturition flow compared to gold standard uroflowmetry and leakage measurements. The system also provides subject-specific information on the relationship between physical activity and urine leakage, thereby eliminating errors due to missing data and recall bias in bladder leakage diaries and circumventing the limitations of office-based uroflowmeters. Full article

Under the influence of global climate change, water conservancy projects located in the high-latitude cold regions of the world are facing severe challenges. This study addresses the contradiction between water supply stability and ecological flow during the dry season in cold regions. Taking Linhai Reservoir as the core, it integrates the HEC-RAS hydrodynamic model with multi-source data such as basin topography, hydro-meteorological data, and water conservancy project parameters to construct a multi-scenario water supply scheduling model during the dry season. The aim is to provide scientific recommendations for different reservoir operation strategies in response to varying frequencies of upstream inflow, based on simulations conducted after the reservoir’s completion. Taking into account winter runoff reduction characteristics and engineering parameters, we simulated the relationships between water level and flow, ecological flow requirements, and urban water shortages. The results indicate that in both flood and normal years, dynamic coordination of storage and discharge can achieve a daily water supply of 120,000 cubic meters, with 100% compliance for the ecological flow rate. For mild and moderate drought years, additional water diversion becomes necessary to achieve 93.5% and 89% supply reliability, respectively. During severe and extreme droughts, significantly reduced reservoir inflows lower ecological compliance rates, necessitating emergency measures, such as utilizing dead storage capacity and exploring alternative water sources. The study proposes operational strategies tailored to different drought intensities: initiating storage adjustments in September for mild droughts and implementing peak-shifting measures by mid-October for extreme droughts. These approaches enhance storage efficiency and mitigate ice blockage risks. This research supports the water supply security and river ecological health of urban and rural areas in Mudanjiang City and Hailin City and provides a certain scientific reference basis for the multi-objective coordinated operation of reservoirs in the same type of high-latitude cold regions. Full article

The COVID-19 pandemic has led to significant shifts in global water consumption, particularly affecting wastewater treatment plants (WWTPs). In Kuwait, where high residential water usage exists, the lockdowns resulting from the pandemic created a unique opportunity to evaluate the effects of altered human activity on wastewater characteristics. This study examines the effects of the lockdown on key wastewater parameters, including flow rate, COD, BOD, TSS, total Kjeldahl nitrogen (TKN), and total phosphorus (TP). Data were collected from four WWTPs in Kuwait over 4 to 8 years, with the Kabd WWTP providing continuous daily data for an 8-year period. A comparative analysis was conducted between pre-lockdown, lockdown, and post-lockdown periods using statistical methods such as paired t-tests. The study also integrates a global comparison to relate Kuwait’s findings. Results indicate a significant increase in wastewater flow (7.6%) during the lockdown, rising from 165,486 m³/d to 178,033 m³/d. COD and BOD levels increased by 27.1% and 18.9%, respectively, while TSS showed the largest rise at 29.9%. TKN increased by 20.1%, indicating higher nitrogenous waste contributions from residential sources. These findings highlight the pandemic’s impact on wastewater characteristics in Kuwait, driven primarily by increased domestic water consumption. The study underscores the necessity of adaptive wastewater management strategies, especially in semi-arid regions, where WWTPs must be equipped to handle unexpected changes in wastewater composition. This research provides essential insights for improving the flexibility of wastewater systems with future disruptions, contributing to both environmental management and public health awareness. Full article

Aquaponics, a biological production system that combines land-based aquaculture and hydroponic cultivation of plants, is a water-sharing and water-saving system that is expected to be a sustainable food production system with water and nutrient resource circulation in agricultural and fisheries fields. The balance among feeding, fish density, and plant absorption capacity was investigated to obtain fundamental data for sustainable aquaponic systems. To clarify the effects of feeding rates on biological production and nitrogen utilization efficiency, fish and plant growth performance and nitrogen flow were evaluated in an aquaponic system that combined loach aquaculture with lettuce hydroponic cultivation. Test groups with different feeding rates and different fish densities were set. As a result, the fertilizer components in loach excreta contributed to plant growth, and the growth rate of lettuce plants tended to be greater than that of control hydroponic cultivation without fish. However, there was no difference in lettuce growth at feeding rates of 0 to 2 g d⁻¹/system, but above 2 g d⁻¹/system, the growth of lettuce plants was suppressed due to an overload of excreta. The yield of loaches increased with increasing daily feeding rate per system, but a minimum feed conversion ratio was detected. The NO₂⁻ concentration increased with increasing daily feeding rate per system and amount of excreta. The nitrogen use efficiency did not change at feeding rates ranging from 0 to 1.5 g d⁻¹/system. In this feeding rate range, 80% of NUE in aquaponics was due to NUE in the plant hydroponic cultivation subsystem. However, above 2 g d⁻¹/system, nitrogen use efficiency decreased with increasing daily feeding rate per system. A feeding rate of approximately 1.5 g d⁻¹/system maximized biological production while maintaining high nitrogen utilization efficiency. In conclusion, a balance among feeding, fish density, and plant absorption capacity is essential to maintain a sustainable aquaponic system for sustainable fish and plant production as a food production system, saving water and chemical fertilizer. Full article