Search Results (51)

Ammonia is emerging as a promising zero-carbon marine fuel due to its high hydrogen density, low storage pressure, and long-term stability, making it well-suited for supporting sustainable maritime energy systems. However, its adoption introduces serious safety challenges, as its toxic, flammable, and corrosive properties pose greater risks than many other alternative fuels, necessitating rigorous risk assessment and safety management. This study presents a comprehensive investigation of potential ammonia leakage scenarios that may arise during the fuel gas supply process within confined compartments of marine vessels, such as the fuel preparation room and engine room. The simulations were conducted using FLACS-CFD V22.2, a validated computational fluid dynamics tool specialized for flammable gas dispersion and explosion risk analysis in complex geometries. The model enables detailed assessment of gas concentration evolution, toxic exposure zones, and overpressure development under various leakage conditions, providing valuable insights for emergency planning, ventilation design, and structural safety reinforcement in ammonia-fueled ship systems. Prolonged ammonia exposure is driven by three key factors: leakage occurring opposite the main ventilation flow, equipment layout obstructing airflow and causing gas accumulation, and delayed sensor response due to recirculating flow patterns. Simulation results revealed that within 1.675 s of ammonia leakage and ignition, critical impact zones capable of causing fatal injuries or severe structural damage were largely contained within a 10 m radius of the explosion source. However, lower overpressure zones extended much further, with slight damage reaching up to 14.51 m and minor injury risks encompassing the entire fuel preparation room, highlighting a wider threat to crew safety beyond the immediate blast zone. Overall, the study highlights the importance of targeted emergency planning and structural reinforcement to mitigate explosion risks in ammonia-fueled environments. Full article

This research addresses the challenge of digitizing the surface of objects in hard-to-reach areas and focuses on the integration of reverse engineering techniques with innovative digitization approaches. Conventional non-destructive testing techniques, such as industrial videoscope inspection, lack the ability to capture accurate geometric and surface information without the need for disassembly of the components. To overcome these limitations, this research proposes a 3D digitizing prototype that integrates structured light, laser scanning, and active stereo techniques. The device utilizes ESP32-CAM modules and compact mechanical components designed for portability and usability in confined spaces. Experimental validation involved scanning complex and reflective surfaces, including printer components and the engine compartment of an automobile, demonstrating the device’s ability to produce detailed point clouds in challenging environments. Key innovations include a unique approach for utilizing 3D scanning techniques of active stereovision using a folding mechanism. The findings highlight the device’s potential for applications in technical diagnostics, industrial inspection, and environments where traditional digitizing technologies could not be utilized. Full article

Compartment fires, such as those occurring in buildings and confined spaces, impose modeling challenges due to the complexity of turbulent flows, combustion, and radiative heat transfer. Computational Fluid Dynamics (CFD) has become a vital tool for understanding and predicting fire dynamics in such situations. This review provides an analysis of different available methods and sub-models on the CFD tools which have been applied to compartment fires in the literature, examining current turbulence, combustion, and radiation approaches. Additionally, it identifies challenges and deficiencies in modeling such as combustion, radiation modeling, flame extinction, and ventilation impacts, discussing the balance between accuracy and computational cost. The review also highlights aspects of different sub-models and provides the reader with informative instruction in making the decisions for a more reliable CFD simulation of the compartment fire. Full article

Background: acute compartment syndrome (ACS) is an orthopedic emergency characterized by pathological pressure elevation within a confined anatomical space, posing a significant challenge in pediatric patients. ACS affects children in a very limited proportion, particularly involving the upper extremities, and diagnosis is complicated by subtle manifestations compared to adults. Case Presentation: we report on the case of a 5-year-old boy who sustained a crush injury to his right hand, resulting in multiple metacarpal fractures and subsequent ACS. The patient presented with severe pain, hand deformity, and restricted mobility. Radiological evaluation confirmed displaced fractures of multiple metacarpals. Emergency surgical intervention involved six incisions to decompress the dorsal and palmar compartments, release muscles, and decompress the median nerve. Healing involved delayed primary closure monitored every 72 h, resulting in an optimal outcome without complications. Conclusions: pediatric upper extremity ACS is rare, complicating diagnosis and treatment due to limited guidelines. This case underscores the effectiveness of early surgical decompression and delayed primary closure in achieving favorable outcomes. Individualized treatment strategies tailored to anatomical considerations and ACS severity are crucial to optimize patient care in pediatric surgical settings. Full article

This study presents an experimental investigation into the effects of fire size on burning characteristics within well-confined military vehicle engine compartments. The research evaluates burning duration, self-extinguishing phenomena, heat release rates, pressure dynamics, and flame morphology using heptane pool fires of varying pan diameters (8 cm, 16 cm, and 24 cm). Key findings include the proportional relationship between fire size and heat release rate, with larger pans causing higher oxygen consumption, elevated pressure differences, and increased total heat flux. Self-extinguishment was observed for larger pans due to oxygen depletion, with extinction time linked to the ratio of compartment volume to heat release rate. Temperature measurements revealed significantly higher ceiling temperatures and heat flux levels for larger fires, emphasizing the structural and thermal risks. These results contribute to understanding fire behavior in confined spaces, offering practical implications for designing fire protection systems tailored to military vehicles. Full article

The growing need for sustainable biotechnological solutions to address environmental challenges, such as climate change and resource depletion, has intensified interest in microbial-based production systems. Synthetic biofilms, which mimic natural microbial consortia, offer a promising platform for optimizing complex metabolic processes that can convert renewable feedstocks into valuable chemicals. In this context, understanding and harnessing the interactions between co-immobilized microorganisms are critical for advancing bioprocesses that contribute to circular bioeconomy goals. In this study, we investigated the viability and metabolic activity of Clostridium carboxidivorans and Clostridium kluyveri within a synthetic, dual-layered biofilm composed of agar hydrogel. This setup compartmentalized each bacterial species. Embedding the bacteria in a structured biofilm offers numerous opportunities for bioproduction, but the inability to monitor cell growth or movement within the immobilization matrix limits process insights. To address this, we adapted a fluorescence in situ hybridization (FISH) protocol, enabling precise, species-specific visualization of bacterial distribution and growth within the gel matrix. Batch processes with the dual-layered biofilm in anaerobic flasks, designed with a metabolic advantage for C. kluyveri, revealed distinct growth dynamics. C. kluyveri exhibited significant metabolic activity, forming clusters at low initial cell concentrations and converting ethanol and acetate into 1-butyrate and 1-hexanoate, indicating viability and cell growth. C. carboxidivorans remained evenly distributed without significant growth or product formation, suggesting that while the cells were viable, they were not metabolically active under the experimental conditions. Both bacterial species were confined to their respective compartments throughout the process, with C. kluyveri showing enhanced substrate conversion at higher initial cell densities in the hydrogel. The pH drop throughout the batch experiment likely contributed to incomplete substrate consumption, particularly for C. kluyveri, which thrives within a narrow pH range. These findings highlight synthetic biofilms as a promising platform for optimizing microbial interactions and improving bioprocess efficiency, especially in applications involving complex metabolic exchanges between co-immobilized microorganisms. Further research will focus on applying conditions to support the growth and metabolic activity of C. carboxidivorans to explore spatial dynamics of bacterial migration and cooperative relationships in the synthetic biofilm. Full article

Increasing numbers of emerging contaminants (ECs) detected in water environments require a detailed understanding of these chemicals’ fate, distribution, transport, and risk in aquatic ecosystems. Modeling is a useful approach for determining ECs’ characteristics and their behaviors in aquatic environments. This article proposes a systematic taxonomy of EC models and addresses gaps in the comprehensive analysis of EC models and their applications. The reviewed models include conventional water quality models, multimedia fugacity models, and machine learning (ML) models. Conventional water quality models have higher prediction accuracy and spatial resolution; nevertheless, they are limited in functionality and can only be used to predict contaminant concentrations in aquatic environments. Fugacity models are excellent at depicting how contaminants travel between different environmental media, but they cannot be used directly to analyze contaminant variations in different parts of the same environmental media because the fugacity model assumes that contaminant concentrations are constant within the same environmental compartment. Compared to other models, ML models can be applied to more scenarios, such as contaminant identification and risk assessments, rather than being confined to the prediction of contaminant concentrations. In recent years, with the rapid development of artificial intelligence, ML models have surpassed fugacity models and conventional water quality models, becoming one of the newest hotspots in the study of ECs. The primary challenge faced by ML models is that the model outcomes are difficult to interpret and understand, and this influences the practical value of an ML model to some extent. Full article

During flight, aircraft cargo compartments are in a confined state. If a fire occurs, it will seriously affect flight safety. Therefore, fire detection systems must issue alarms within seconds of a fire breaking out, necessitating high real-time performance for aviation fire detection systems. In addressing the issue of fire target detection, the YOLO series models demonstrate superior performance in striking a balance between computational efficiency and recognition accuracy when compared with alternative models. Consequently, this paper opts to optimize the YOLO model. An enhanced version of the FDY-YOLO object detection algorithm is introduced in this paper for the purpose of instantaneous fire detection. Firstly, the FaB-C3 module, modified based on the FasterNet backbone network, replaces the C3 component in the YOLOv5 framework, significantly decreasing the computational burden of the algorithm. Secondly, the DySample module is used to replace the upsampling module and optimize the model’s ability to extract the features of small-scale flames or smoke in the early stages of a fire. We introduce RFID technology to manage the cameras that are capturing images. Finally, the model’s loss function is changed to the MPDIoU loss function, improving the model’s localization accuracy. Based on our self-constructed dataset, compared with the YOLOv5 model, FDY-YOLO achieves a 0.8% increase in mean average precision (mAP) while reducing the computational load by 40%. Full article

Background: Biphenotypic sinonasal sarcoma is a rare low-grade tumor arising from the sinonasal tract, featuring locally aggressive biological behavior, with a tendency to invade the orbit and skull base. There are no defined guidelines of treatment; thus, the management varies among different institutions. The aim of the present study is to provide a modular system of surgical approaches according to the lesion pattern of growth from a literature review. Materials and Methods: A comprehensive and detailed literature review on the PubMed and Embase online electronic databases on biphenotypic sinonasal sarcoma with orbital invasion was conducted. A personal case exhibiting peculiar features was also added. Demographic (patient’s sex and age), clinical (presenting symptoms and time to treatment), neuroradiological (anatomical origin and pattern of growth), and treatment (type of treatment, surgical approach, extent of resection, peri- and postoperative complications, and adjuvant therapies) data, as well as clinical outcome, recurrence rates, and overall survival, were analyzed. Results: Thirty-one patients harboring biphenotypic sinonasal sarcoma with orbital invasion were identified. Tumors mainly affected female patients (66.7%) and a middle-aged population (median 55.2 years old). Simultaneous skull base involvement occurred in most cases (80.6%). Surgery was performed in all but one case (97%), as unique treatment (59%) or in association with radio—(23.5%) and/or chemotherapy (5.9%/2.9%), allowing for gross total tumor resection in most cases (66.7%). The endoscopic endonasal approach was the most adopted surgical corridor (51.7%). The local recurrence rate was 19.3%, and only two cases of tumor-related mortality occurred. Conclusions: Surgery is the only curative treatment, with the main goal to restore/improve/arrest progression of clinical manifestations. The endoscopic endonasal route represents the master approach for lesions confined to the midline. Microsurgical transcranial and endoscopic transorbital approaches have a complementary role for addressing the lesion’s component with large intracranial extension or affecting the paramedian aspect of the anterior cranial fossa and superior–lateral orbital compartment, respectively. The approach selection should be made case by case according to the tumor pattern of growth. Full article

Many compartments are prone to pose safety hazards such as loose fasteners or object intrusion due to their confined space, making manual inspection challenging. To address the challenges of complex inspection environments, diverse target categories, and variable scales in confined compartments, this paper proposes a novel GMS-YOLO network, based on the improved YOLOv8 framework. In addition to the lightweight design, this network accurately detects targets by leveraging more precise high-level and low-level feature representations obtained from GhostHGNetv2, which enhances feature-extraction capabilities. To handle the issue of complex environments, the backbone employs GhostHGNetv2 to capture more accurate high-level and low-level feature representations, facilitating better distinction between background and targets. In addition, this network significantly reduces both network parameter size and computational complexity. To address the issue of varying target scales, the first layer of the feature fusion module introduces Multi-Scale Convolutional Attention (MSCA) to capture multi-scale contextual information and guide the feature fusion process. A new lightweight detection head, Shared Convolutional Detection Head (SCDH), is designed to enable the model to achieve higher accuracy while being lighter. To evaluate the performance of this algorithm, a dataset for object detection in this scenario was constructed. The experiment results indicate that compared to the original model, the parameter number of the improved model decreased by 37.8%, the GFLOPs decreased by 27.7%, and the average accuracy increased from 82.7% to 85.0%. This validates the accuracy and applicability of the proposed GMS-YOLO network. Full article

Stable isotope-resolved metabolomics comprises a critical set of technologies that can be applied to a wide variety of systems, from isolated cells to whole organisms, to define metabolic pathway usage and responses to perturbations such as drugs or mutations, as well as providing the basis for flux analysis. As the diversity of stable isotope-enriched compounds is very high, and with newer approaches to multiplexing, the coverage of metabolism is now very extensive. However, as the complexity of the model increases, including more kinds of interacting cell types and interorgan communication, the analytical complexity also increases. Further, as studies move further into spatially resolved biology, new technical problems have to be overcome owing to the small number of analytes present in the confines of a single cell or cell compartment. Here, we review the overall goals and solutions made possible by stable isotope tracing and their applications to models of increasing complexity. Finally, we discuss progress and outstanding difficulties in high-resolution spatially resolved tracer-based metabolic studies. Full article

Background: In recent years, preimplantation genetic testing for aneuploidies (PGT-A) has become widespread in assisted reproduction. However, contrary to expectations, PGT-A does not significantly improve the clinical outcomes of assisted reproductive technologies. One of the underlying reasons is the discordance between the PGT-A results and the true chromosomal constitution of the blastocyst. In this case series, we re-examined the PGT-A results in trophectoderm (TE) re-biopsies and in the two isolated blastocyst compartments—the TE and the inner cell mass (ICM). Methods: This study enrolled 23 human blastocysts from 17 couples who were referred for assisted reproduction. The blastocysts were unsuitable for uterine transfer due to the chromosomal imbalance revealed by PGT-A using array comparative genomic hybridization (aCGH) (n = 11) or next-generation sequencing (NGS) (n = 12). The re-examination of the PGT results involved two steps: (1) a TE re-biopsy with subsequent aCGH and (2) blastocyst separation into the TE and the ICM with a subsequent cell-by-cell analysis of each isolated compartment by fluorescence in situ hybridization (FISH) with the DNA probes to chromosomes 13, 16, 18, 21, and 22 as well as to the PGT-A detected imbalanced chromosomes. Results: In 8 out of 23 cases, the PGT-A results were concordant with both the re-biopsy and the isolated TE and ICM analyses. The latter included the diagnoses of full non-mosaic aneuploidies (five cases of trisomies and two cases of monosomies). In one case, the results of PGT-A, aCGH on the TE re-biopsy, and FISH on the isolated TE showed Xp tetrasomy, which contrasted with the FISH results on the isolated ICM, where this chromosomal pathology was not detected. This case was classified as a confined mosaicism. In 4 out of 23 cases, the results were partially discordant. The latter included one case of trisomy 12, which was detected as non-mosaic by PGT-A and the re-biopsy and as mosaic by FISH on the isolated TE and ICM. This case was classified as a true mosaicism with a false negative PGT-A result. In 11 out of 23 cases, the re-examination results were not concordant with the PGT-A results. In one of these discordant cases, non-mosaic tetraploidy was detected by FISH in the isolated TE and ICM, whereas the PGT-A and the TE re-biopsy failed to detect any abnormality, which advocated for their false negative result. In two cases, the re-examination did not confirm full aneuploidies. In eight cases, full or partial mosaic aneuploidies as well as chaotic mosacism were not confirmed in the isolated TE nor the isolated ICM. Thus, in 47.8% of cases, the PGT-A results did not reflect the true chromosomal constitution of a blastocyst. Conclusions: The PGT results may have different prognostic value in the characterization of the chromosomal constitution of a blastocyst. The detected non-mosaic aneuploidies have the highest prognostic value. In stark contrast, most PGT-identified mosaic aneuploidies fail to characterize the true chromosomal constitution of a blastocyst. Once detected, a differential diagnosis is needed. Full article

In this research, the influence of confined space size on the temperature distribution characteristics of internal window plumes from well-ventilated compartment fires was studied. Theoretical analysis was firstly used to establish a mathematical model for the smoke after ejecting from the window in the space. The study considered fire heat release rate and vertical height as dependent variables. Numerical simulations and experimental methods were carried out to study the temperature variations. A critical distance L₂ was obtained. Results show that when the space D between the vertical retaining wall and the building façade is greater than L₂, the variation of D has little influence on radial temperature. Once D is less than L₂, the radial temperature distribution inside the confined space will tend to be consistent, and the temperature in the confined space sharply increases as D decreases. In addition, a dimensionless model was derived to quantify the relationship between temperature rise and vertical height. The experimental and numerical simulation results were processed, which are in good agreement with the model. The study can provide a framework for managing building safety. Full article

Microalgae are highly regarded as ideal materials for the creation of liquid biofuels and have substantial potential for growth and utilization. However, traditional storage and culture methods for microalgae are plagued by challenges such as uncontrolled growth, bacterial contamination, and self-shading among algae. These issues severely impede the photosynthetic process and the efficient extraction of biomass energy. This study tackles these problems by utilizing magnetic hydrophobic protein particles to stabilize water-in-oil Pickering emulsions. This allows for the micro-compartment storage and magnetic transfer of algae. Additionally, the successful encapsulation of Chlorella cells in high-internal-phase water-in-oil Pickering emulsions effectively mitigates the settling problem of Chlorella cells in the liquid phase, thereby enabling the potential use of Pickering emulsions for the confined cultivation of microalgae. Full article

Na-K-2Cl cotransporter 1 (NKCC1) regulates chloride influx in neurons and thereby GABA_A receptor activity in normal and pathological conditions. Here, we characterized in hippocampal neurons the membrane expression, distribution and dynamics of exogenous NKCC1a and NKCC1b isoforms and compared them to those of the chloride extruder K-Cl cotransporter 2 (KCC2). We found that NKCC1a and NKCC1b behave quite similarly. NKCC1a/1b but not KCC2 are present along the axon initial segment where they are confined. Moreover, NKCC1a/1b are detected in the somato-dendritic compartment at a lower level than KCC2, where they form fewer, smaller and less compact clusters at perisynaptic and extrasynaptic sites. Interestingly, ~60% of dendritic clusters of NKCC1a/1b are colocalized with KCC2. They are larger and brighter than those devoid of KCC2, suggesting a particular NKCC1a/1b-KCC2 relationship. In agreement with the reduced dendritic clustering of NKCC1a/1b compared with that of KCC2, NKCC1a/1b are more mobile on the dendrite than KCC2, suggesting weaker cytoskeletal interaction. NKCC1a/b are confined to endocytic zones, where they spend more time than KCC2. However, they spend less time in these compartments than at the synapses, suggesting that they can rapidly leave endocytic zones to increase the membrane pool, which can happen in pathological conditions. Thus, NKCC1a/b have different membrane dynamics and clustering from KCC2, which helps to explain their low level in the neuronal membrane, while allowing a rapid increase in the membrane pool under pathological conditions. Full article