Search Results (33)

Underwater navigation remains constrained by technological limitations, driving the exploration of alternative approaches such as polarized light-based systems. This review systematically examines advances in polarized navigation from three perspectives. First, the principles of atmospheric polarization navigation are analyzed, with their operational mechanisms, advantages, and inherent constraints dissected. Second, innovations in bionic polarization multi-sensor fusion positioning are consolidated, highlighting progress beyond conventional heading-direction extraction. Third, emerging underwater polarization navigation techniques are critically evaluated, revealing that current methods predominantly adapt atmospheric frameworks enhanced by advanced filtering to mitigate underwater interference. A comprehensive synthesis of underwater polarization modeling methodologies is provided, categorizing physical, data-driven, and hybrid approaches. Through rigorous analysis of studies, three persistent barriers are identified: (1) inadequate polarization pattern modeling under dynamic cross-media conditions; (2) insufficient robustness against turbidity-induced noise; (3) immature integration of polarization vision with sonar/IMU (Inertial Measurement Unit) sensing. Targeted research directions are proposed, including adaptive deep learning models, multi-spectral polarization sensing, and bio-inspired sensor fusion architectures. These insights establish a roadmap for developing reliable underwater navigation systems that transcend current technological boundaries. Full article

The slow action of fungi is one of the biggest challenges in using entomopathogenic fungi. A promising alternative to reduce the time of action is to combine conidia with extracellular enzymes. This study aimed to characterize the production of Pr1 subtilisin protease and lipases by Beauveria bassiana and Metarhizium anisopliae in different culture media and to evaluate the efficiency of the enzymatic treatment against Aphis gossypii and Spodoptera frugiperda. The isolates were cultivated in five different liquid cultures, and, after 7 days, the culture was filtered and centrifuged, and the activity of the Pr1 and lipases was measured. The fungi cultured in a Luria–Bertani broth medium had the highest activity of proteases and lipases. The mortality of A. gossypii nymphs treated with conidia 7 days after the treatment was 39% (JEF-410), 76.5% (JEF-492), 74.8% (ERL-836), and 70.9% (JEF-214). The B. bassiana JEF-410 supernatant combined with conidia increased the fungal virulence at day 5 and day 6 after treatment. When S. frugiperda larvae were treated with B. bassiana JEF-492 conidia combined with its supernatant, the time of infection was shorter compared to the larvae treated with conidia only. Once the supernatant was incubated at 37 °C, the relative activity decreased from 100% to 80% after 2 h and to 45% after 24 h. The results suggest that the supernatant of entomopathogenic fungi may be formulated and used as a biopesticide in an efficient strategy for the biological control of pests. Full article

Due to their electroconductive properties, flexible open-cell polyurethane foam/silver nanowire (PUF/AgNW) structures can provide an alternative for the construction of cheap pressure transducers with limited lifetimes or used as filter media for air conditioning units, presenting bactericidal and antifungal properties. In this paper, highly electroconductive metal-polymer hybrid foams (MPHFs) based on AgNWs were manufactured and characterized. The electrical resistance of MPHFs with various degrees of AgNW coating was measured during repeated compression. For low degrees of AgNW coating, the decrease in electrical resistance during compression occurs in steps and is not reproducible with repeated compression cycles due to the reduced number of electroconductive zones involved in obtaining electrical conductivity. For high AgNW coating degrees, the decrease in resistance is quasi-linear and reproducible after the first compression cycle. However, after compression, cracks appear in the foam cell structure, which increases the electrical resistance and decreases the mechanical strength. It can be considered that PUFs coated with AgNWs have a compression memory effect and can be used as cheap solutions in industrial processes in which high precision is not required, such as exceeding a maximum admissible load or as ohmic seals for product security. Full article

Air pollution is becoming a serious issue because it negatively impacts the quality of life. One of the first most useful self-defense approaches against air pollution are face masks. Typically made of non-renewable petroleum-based polymers, these masks are harmful to the environment, and they are mostly disposable. Poly(butylene succinate) (PBS) is regarded as one of the most promising materials because of its exceptional processability and regulated biodegradability in a range of applications. In this regard, nanofiber-based face masks are becoming more and more popular because of their small pores, light weight, and excellent filtration capabilities. Centrifugal spinning (CS) provides an alternative method for producing nanofibers from various materials at high speeds and low costs. This current study aimed to investigate the effect of processing parameters on the resultant PBS fiber morphology. Following that, the usability of PBS nonwoven as a filter media was investigated. The effects of solution concentration, rotating speed, and needle size have been examined using a three-factorial Box–Behnken experimental design. The results revealed that PBS concentration had a substantial influence on fiber diameter, with a minimum fiber diameter of 172 nm attained under optimum production conditions compared to the anticipated values of 166 nm. It has been demonstrated that the desired function and the Box–Behnken design are useful instruments for predicting the process parameters involved in the production of PBS nanofibers. PBS filters can achieve an excellent efficiency of more than 98% with a pressure drop of 238 Pa at a flow rate of 85 L/min. The disposable PBS filter media was able to return to nature after use via hydrolysis processes. The speed and cost-effectiveness of the CS process, as well as the environmentally benign characteristics of the PBS polymer, may all contribute considerably to the development of new-age filters. Full article

Stormwater runoff from expressways generally has high concentrations of heavy metals. However, the heavy metal removal of conventional sand filters is low, so a better alternative is required. In this study, several inexpensive materials were tested for their heavy metal adsorption, and the performances of the selected materials were evaluated via field tests. The results of laboratory experiments showed that the Cu adsorption capacity followed the order of Na-zeolite > zeolite > biochar > granular ferric hydroxide > sand ≥ orchid stone. The performance of a pilot-scale dual-media filter filled with Na-zeolite and mortar granules was monitored for four rainfall events at an expressway site, and was compared to that of a sand filter. Both filters showed similar event mean concentration (EMC) removal for BOD, COD, TOC, and T-N, without a notable decrease in hydraulic conductivity. However, the removal of T-P, Cu, Zn, Cr, Ni, and Fe by the dual-media filter was 37.6–74.8%, 59.1–90.1%, 84.9–99.7%, 100.0%, 100.0%, and 78.7–94.4%, respectively, which was up to 4.5 times of that of the sand filter. In addition, it was stable regardless of the influent EMCs. Overall, we showed that the dual-media filter is excellent in heavy metal removal from stormwater runoff, with negligible clogging. Full article

Microalgae are mostly phototrophic microorganisms present worldwide, showcasing great adaptability to their environment. They are known for producing essential metabolites such as carotenoids, chlorophylls, sterols, lipids, and many more. This study discusses the possibility of the mixotrophic abilities of microalgae in the presence of food waste oils. The utilization of food waste materials is becoming more popular as a research subject as its production grows every year, increasing the environmental burden. In this work, waste frying oil and coffee oil were tested for the first time as a nutrition source for microalgae cultivation. Waste frying oil is produced in large amounts all over the world and its simple purification is one of its greatest advantages as it only needs to be filtered from leftover food pieces. Coffee oil is extracted from waste spent coffee grounds as a by-product. The waste frying oil and coffee oil were added to the basic algal media as an alternative source of carbon. As a pilot study for further experimentation, the effect of oil in the medium, algal adaptability, and capability to survive were tested within these experiments. The growth and production characteristics of four algae and cyanobacteria strains were tested, of which the strain Desmodesmus armatus achieved exceptional results of chlorophyll (8.171 ± 0.475 mg/g) and ubiquinone (5.708 ± 0.138 mg/g) production. The strain Chlamydomonas reindhartii showed exceptional lipid accumulation in the range of 30–46% in most of the samples. Full article

Alternative polymer-based filter media and ornamental plants in constructed wetlands (CWs) are a relatively unexplored field. These approaches have the potential to reduce construction costs and enhance the aesthetic appearance of CWs. This study evaluated for the first time the use of ornamental plants as monoculture and polyculture, as well as the incorporation of polyethylene terephthalate (PET) as a filter medium in a large-scale community HC (divided into 12 cells) for the treatment of municipal wastewater. Duplicate cells were planted with monocultures of Canna hybrids, Spathiphyllum blandum, Anturium spp., and Thypa spp., while two units had mixed cultures of these plants and two control units remained without vegetation. Systems with vegetation achieved average removal efficiencies of 86.95, 81.3, 64.6, 85.2, and 52% for COD, BOD₅, TSS, TP, and TN, respectively. Meanwhile, in systems without vegetation, the removal efficiencies for these pollutants were 81.33, 72.86, 43.68, 3.93, and 30.70%, respectively, indicating significant differences between vegetated and non-vegetated systems (p < 0.05). The PET-based filter medium showed effective pollutant removal, with values comparable to or surpassing those reported in existing literature. All ornamental species exhibited good development with new offspring and flower production both in monoculture and in polyculture. The use of such a filter medium and ornamental vegetation could make CWs more attractive to rural communities. Full article

Titanium surface modifications are widely used to modulate cellular behavior by recognition of topographical cues. However, how those modifications affect the expression of mediators that will influence neighboring cells is still elusive. This study aimed to evaluate the effects of conditioned media from osteoblasts cultured on laser-modified titanium surfaces on the differentiation of bone marrow cells in a paracrine manner and to analyze the expression of Wnt pathway inhibitors. Mice calvarial osteoblasts were seeded on polished (P) and Yb:YAG laser-irradiated (L) Ti surfaces. Osteoblast culture media were collected and filtered on alternate days to stimulate mice BMCs. Resazurin assay was performed every other day for 20 days to check BMC viability and proliferation. After 7 and 14 days of BMCs maintained with osteoblasts P and L-conditioned media, alkaline phosphatase activity, Alizarin Red staining, and RT-qPCR were performed. ELISA of conditioned media was conducted to investigate the expression of Wnt inhibitors Dickkopf-1 (DKK1) and Sclerostin (SOST). BMCs showed increased mineralized nodule formation and alkaline phosphatase activity. The L-conditioned media enhanced the BMC mRNA expression of bone-related markers Bglap, Alpl, and Sp7. L-conditioned media decreased the expression of DKK1 compared with P-conditioned media. The contact of osteoblasts with Yb:YAG laser-modified Ti surfaces induces the regulation of the expression of mediators that affect the osteoblastic differentiation of neighboring cells. DKK1 is among these regulated mediators. Full article

Particulate matter air pollution and volatile organic compounds released into the air from the incomplete combustion of fossil fuels and wildfires creates significant damage to human health and the environment. Advances in air filtration and purification technology are needed to mitigate aerosol hazards. This article details an effort to explore the potential benefits of new materials and methods for the production of nonwoven air filtration media through electrospinning and stabilizing polyacrylonitrile fibers. The investigated production methods include electrospinning fibrous matting onto a stainless steel wire mesh and stabilizing the nonwoven media in a chamber furnace. The media is then tested for air filtration penetration and airflow resistance, and the fiber size distribution is measured using scanning electron microscopy. The experimental results show that the electrospun media approaches the performance criteria for airflow resistance and particle capture efficiency of high-efficiency particulate air (HEPA) filter media. Furthermore, performance estimations for electrospun media of increased thickness and for a decreased filtration velocity show potential to exceed the HEPA media resistance and efficiency criteria. Thus, it is suggested that electrospun and stabilized nonwoven fibrous media are candidates as alternatives to traditionally manufactured HEPA media and may potentially benefit modern air filtration technology and reduce hazards associated with particulate matter. Additionally, the authors recommend future exploration into the carbonization and activation of electrospun filter media for the adsorption and mitigation of volatile organic compounds as a secondary benefit, while maintaining high efficiency and low airflow resistance in the removal of particulate matter from aerosol streams. Full article

The worldwide known and employed spice of Asian origin, turmeric, receives significant attention due to its numerous purported medicinal properties. Herein, we report an optimized synthesis of curcumin and symmetric curcuminoids of aromatic (bisdemethoxycurcumin) and heterocyclic type, with yields going from good to excellent using the cyclic difluoro-boronate derivative of acetylacetone prepared by reaction of 2,4-pentanedione with boron trifluoride in THF (ca. 95%). The subsequent cleavage of the BF₂ group is of significant importance for achieving a high overall yield in this two-step procedure. Such cleavage occurs by treatment with hydrated alumina (Al₂O₃) or silica (SiO₂) oxides, thus allowing the target heptanoids obtained in high yields as an amorphous powder to be filtered off directly from the reaction media. Furthermore, crystallization instead of chromatographic procedures provides a straightforward purification step. The ease and efficiency with which the present methodology can be applied to synthesizing the title compounds earns the terms “click” and “unclick” applied to describe particularly straightforward, efficient reactions. Furthermore, the methodology offers a simple, versatile, fast, and economical synthetic alternative for the obtention of curcumin (85% yield), bis-demethoxycurcumin (78% yield), and the symmetrical heterocyclic curcuminoids (80–92% yield), in pure form and excellent yields. Full article

Particle emissions into the atmosphere can cause extensive damage to the environment and human health. To improve the efficiency in the collection of submicronic particles, new filtration media appeared on the market due to new textile technologies and equipment, such as filter media developed with polytetrafluoroethylene (PTFE) membranes; however, these are more expensive. A filter coating technique called precoating is a more economical alternative that could enhance filtration efficiency. This paper aimed to evaluate the operational parameters of precoating for micro- and nanoparticle filtration and compare the results with those obtained from the PTFE membrane. For this purpose, filtration cycles were performed, using precoated polyester with hydrated lime and dolomitic limestone, polyester with a PTFE membrane, and steel industry ultrafine dust. The results showed that the precoated polyester had a longer cycle duration and lower pressure drop than the polyester with a PTFE membrane. Therefore, precoating was shown to be a great alternative to be used in bag filters in steel mills because it presented high collection efficiency for submicronic particles, in addition to increasing the bag lifespan with less energy expenditure. Full article

Sunscreens have become a product based on increasingly complex formulations that include, among many ingredients, a mixture of UV filters to provide optimal sun ultraviolet radiation protection. A significant group of scientific works deals with the impact of UV filters in aquatic media. However, the knowledge of the mechanism and kinetics of the compound’s direct release, fate, and its transformation and interaction with living organisms is necessary to assess its environmental occurrence and behavior and to predict potential and real impacts on the aquatic environment. This review outlines the existing analysis and modeling of the release and behavior of sunscreen’s ingredients in the marine environment, including aquatic organisms. The physical-chemical properties, photodegradation, and release kinetics of particles and chemicals into the water are studied by hydrodynamic and kinetic models. Direct photolysis of chemicals is modeled as pseudo-first-order kinetics, while the indirect pathway by the reaction of sunscreen with reactive oxygen species is described as second-order kinetics. The interaction of UV filters with marine biota is studied mainly by toxicokinetic models, which predict their bio-accumulation in the organisms’ tissues. These models consider the chemicals’ uptake and excretion, as well as their transfer between different internal animal organs, as a first-order kinetic process. The studies analyzed in the present work represent a driver of change for the beauty and personal care industry, in order to seek new ecological alternatives through the application of R&D tactics. Full article

Organizations responsible for seismic and volcanic monitoring worldwide mainly gather information from instrumental networks composed of specialized sensors, data-loggers, and transmission equipment. This information must be available in seismological data centers to improve early warning diffusion. Furthermore, this information is necessary for research purposes to improve the understanding of the phenomena. However, the acquisition data systems could have some information gaps due to unstable connections with instrumental networks and repeater nodes or exceeded waiting times in data acquisition processes. In this work, we performed a systematic review around information availability issues and solutions in data acquisition systems, instrumental networks, and their interplay with transmission media for seismic and volcanic monitoring. Based on the SLR methodology proposed by Kitchenham, B., a search string strategy was considered where 1938 articles were found until December 2021. Subsequently, through selection processes, 282 articles were obtained and 51 relevant articles were extracted using filters based on the content of articles mainly referring to seismic–volcanic data acquisition, data formats, monitoring networks, and early warnings. As a result, we identified two independent partial solutions that could complement each other. One focused on extracting information in the acquisition systems corresponding to continuous data generated by the monitoring points through the development of mechanisms for identifying sequential files. The other solution focused on the detection and assessment of the alternative transmission media capabilities available in the seismic–volcanic monitoring network. Moreover, we point out the advantage of a unified solution by identifying data files/plots corresponding to information gaps. These could be recovered through alternate/backup transmission channels to the monitoring points to improve the availability of the information that contributes to real-time access to information from seismic–volcanic monitoring networks, which speeds up data recovery processes. Full article

During summer and winter months, pastures and outdoor pens represent the conventional means of providing exercise for dairy cows housed in tie-stall barns in the province of Québec, Canada. Unfortunately, outdoor pens require large spaces, and their leachates do not meet Québec’s environmental regulations. Therefore, there is a need to develop alternative approaches for these so-called wintering pens. A sustainable year-long approach could be a stand-off pad consisting of a filtering media to manage adequately water exiting the pad. Different filtering materials can be used and mixed (gravel, woodchips, biochar, sphagnum peat moss, sand, etc.). To find the best material and/or mixes, a laboratory study was carried out using 15 PVC pipes (5 cm in diameter and 50 cm long) to test five different combinations of materials over a 3-week period. Different contaminant-removal efficiencies were achieved with the alternative materials, including for chemical oxygen demand (11–38%), phosphates (8–23%), suspended solids (33–57%), and turbidity (23–58%). Alternative treatments with sand, sphagnum peat moss, and biochar improved the filtration capacity when compared to the conventional material (woodchips). However, after three weeks of experimentation, the treatment efficiency of sand gradually decreased for pollutants such as suspended solids and phosphates. Full article

Background: Lanthanum carbonate is a phosphate binder used in advanced kidney disease. Its radiopaque appearance has been described in many case studies and case series. Misinterpretation of this phenomenon leads to unnecessary diagnostic tests and procedures. The objectives of this study were to summarize the literature on lanthanum carbonate opacities and present a visual overview. Methods: A systematic search was conducted using MEDLINE, Embase, and Web of Science. We included all types of studies, including case reports/studies, describing radiological findings of lanthanum carbonate opacities in patients with chronic kidney disease. No filter for time was set. Results: A total of 36 articles were eligible for data extraction, and 33 articles were included in the narrative synthesis. Lanthanum carbonate opacities were most commonly reported in the intestines (26 studies, 73%), stomach (8 studies, 21%), and the aerodigestive tract (2 studies, 6%). The opacities in the intestine were most frequently described as multiple, scattered radiopaque densities, compared with the aerodigestive tract, where the opacities were described as a single, round foreign body. Suspicion of contrast medium or foreign bodies was the most common differential diagnosis. LC opacities in patients with CKD are commonly misinterpreted as foreign bodies or suspect contrast media. Conclusions: CKD patients treated with LC may have opacities throughout the digestive tract that can vary in appearance. Stopping LC treatment or changing to an alternative phosphate binder prior to planned image studies can avoid diagnostic confusion. If this is not an option, knowledge of the presentation of LC opacities is important. Full article