Search Results (435)

An aerobic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium, strain AK1^T, was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka, Russia. The cells of the new isolate were Gram-negative motile rods with a single polar flagellum. Strain AK1^T grew at 37–55 °C (optimum 50 °C) with 0–1.0% NaCl (optimum 0%) and within the pH range 4.8–7.0 (optimum pH 5.2–5.5). The new isolate was able to grow by aerobic respiration with sulfide, sulfur, or thiosulfate as the electron donor and HCO₃⁻/CO₂ as the carbon source. The major fatty acids were C16:0, C17:1 Δ, and C16:1 ω7c. The respiratory lipoquinone was ubiquinone UQ-8. The size of the genome and genomic DNA G+C content of the strain AK1^T were 2.55 Mb and 64.0%, respectively. The closest 16S rRNA gene sequence of a validly published species belonged to Thiobacter subterraneus C55^T (97.94% identity). According to the 16S rRNA gene sequence-based and conserved protein sequences-based phylogenetic analyses, strain AK1^T represented a distinct lineage of the genus Thiobacter within a new family, Thiobacteraceae of the order Burkholderiales. As inferred from the morphology, physiology, chemotaxonomy, and phylogeny, strain AK1^T ought to be recognized as a novel species for which we propose the name Thiobacter aerophilum sp. nov. The type strain is AK1^T (=CGMCC 1.18099^T = UQM 41819^T). Full article

Agrivoltaics (APVs) represent a growing technology in Europe that enables the co-location of energy and food production in the same field. Photosynthesis requires photosynthetic active radiation, which is reduced by the shadows cast on crops by APV panels. The design of the module rows, material, and field orientation significantly influences the radiation distribution on the ground. In this context, we introduce an innovative approach for the effective simulation of the shading effects of various APV designs. We performed an extensive sensitivity analysis of the photovoltaic (PV) geometry influence on the ground-incident radiation and crop growth of selected cultivars. Simulations (2013–2021) for three representative arable crops in eastern Austria (winter wheat, spring barley, and maize) and seven different APV designs that only limited to the shading effect showed that maize and spring barley experienced the greatest annual above-ground biomass and grain yield reduction (up to 25%), with significant differences between the APV design and the weather conditions. While spring barley had similar decreases within the years, maize was characterized by high variability. Winter wheat had only up to a 10% reduction due to shading and a reduced photosynthetic performance. Cold/humid/cloudy weather during the growing season had more negative yield effects under APVs than dry/hot periods, particularly for summer crops such as maize. The lowest grain yield decline was achieved for all three crops in the APV design in which the modules were oriented to the east at a height of 5 m and mounted on trackers with an inclination of +/−50°. This scenario also resulted in the highest land equivalent ratios (LERs), with values above 1.06. The correct use of a tracker on APV fields is crucial for optimizing agricultural yields and electricity production. Full article

Chronic immune sensory polyradiculopathy (CISP) is a rare inflammatory immune disorder affecting the nervous system, primarily targeting the proximal sensory nerve roots. The condition was first described by Sinreich in 2004. We conducted a systematic review of CISP cases published on PubMed to identify common clinical presentations, along with neurophysiological, radiological, cerebrospinal fluid (CSF), and other findings. Our review included a total of 22 patients from 8 articles. Many patients presented with gait difficulties and sensory ataxia and were found to have normal nerve conduction studies (NCS) and electromyography (EMG) but exhibited characteristic abnormalities in somatosensory evoked potentials (SSEP), elevated CSF protein levels, thickened nerve roots on contrast-enhanced lumbar spine MRIs, and histological changes on nerve root biopsies. Clinical improvement was observed following treatment with steroids and/or intravenous immunoglobulin (IVIG). The study concluded that while CISP is rare, it is an important clinical entity to consider, as accurate diagnosis and appropriate treatment can lead to significant improvements in neurological symptoms and disabilities. Full article

Trees positively improve the annual thermal comfort of the built environment in tropical areas, where climate change is slight throughout the year. However, for areas with high changes in climate all year, the current studies have only explored the summer cooling performance of trees without the impact of different types of trees on annual thermal comfort, especially in cold seasons. Therefore, to quantify the impacts and scientifically guide the optimization of green space layout in hot summer and cold winter areas, this study selected Changsha City as the study area and analyzed how the annual thermal comfort is affected by evergreen trees and deciduous trees, which are two common types of trees in hot summer and cold winter areas. The analytical results indicated that the difference in the effect of deciduous and evergreen trees on outdoor thermal comfort was insignificant in summer, where the difference in the monthly mean PET for the three summer months was slight, being 0.28 °C, 0.14 °C, and 0.29 °C, respectively. However, evergreen trees greatly exacerbated winter cold compared to deciduous trees, with a monthly mean PET decrease by nearly 1.0 °C and an hourly PET reduced by up to 3.57 °C. The difference is mainly attributed to the absorption and reflection of solar radiation by the tree canopy, as well as the cooling and humidifying effect of the tree leaf. In hot summer and cold winter areas, outdoor thermal comfort is still in the “comfortable” and “slightly warm” acceptable stage despite the warming effect of deciduous trees in the spring and autumn seasons. Planting evergreen trees is an inevitable thermal mitigation choice for tropical areas. However, for the areas with high annual climate change, such as hot summer and cold winter areas in China, a change in empirical tree planting patterns and selecting deciduous trees where appropriate will improve year-round outdoor thermal comfort. Full article

Given the complex terrain and economic development status of Guizhou Province, research on tropospheric NO₂ column concentration using satellite remote sensing is still insufficient. Observing the spatial–temporal evolution characteristics of tropospheric NO₂ column concentration can ensure the stable development of air quality. Based on the Google Earth Engine (GEE) platform, NO₂ column concentration data retrieved from Sentinel-5P TROPOMI were analyzed using spatial autocorrelation, hotspot analysis, and geographic detector methods (Geodetector). The results show that NO₂ column concentration in Guizhou Province exhibits seasonal variation, characterized by higher levels in winter and lower levels in summer, with transitional values in spring and autumn. The annual average concentration was highest in 2021 at 3.47 × 10⁻⁵ mol/m² and lowest in 2022 at 2.85 × 10⁻⁵ mol/m². Spatially, NO₂ column concentration displays a distribution pattern of “high in the west, low in the east; high in the north, low in the south”, with significant spatial clustering. The distribution of cold and hot spots aligns with areas of high and low values. NO₂ column concentration is primarily influenced by socio-economic factors, with the interaction between any two factors enhancing the explanatory power of individual factors on NO₂ column concentration. Full article

A favorable thermal environment in fitness centers is important to attract more members and is beneficial to the health of exercising people. The purpose of this study was to research the actual thermal environment of a typical fitness center in different seasons and the thermal requirement of exercising people. A field investigation covering winter, spring, and summer was conducted. The environmental parameters were measured. Subjective questionnaires involving individual information, clothing insulation, thermal sensation, etc., were collected. Participants’ heart rates were tested to estimate their metabolic rate (MR). A total of 740 valid questionnaires were collected. The results showed that a scissors gap existed between the predictive mean vote (PMV) and the thermal sensation vote (TSV) for the exercising people. For the higher MR group, there was a separation between the TSV and thermal preference vote, e.g., most participants would not prefer to cooler or warmer thermal environment when they felt hot or cold. The CO₂ concentration changed greatly among seasons and the distribution in the fitness center was not uniform. With mechanical ventilation, the CO₂ concentration in summer was the lowest. In other seasons it became much higher due to limited natural ventilation. However, subjective response to indoor air quality showed no significant difference among seasons. The participants felt more satisfied to the overall thermal environment in the transition season. The results can be referenced in the thermal environment management in fitness centers during seasonal changes. Full article

As a propulsor with a good application prospect, the flapping foil has been a hot research topic in the past decade. Although the research results of flapping foils have been very abundant, the performance-influencing mechanism of flapping foils is still not perfect, and the research considering three-dimensional (3D) effects for engineering applications is still very limited. Based on the above considerations, a systematic and parametric analysis of a small aspect ratio flapping foil is conducted to correlate the influencing factors including angle of attack (AoA) characteristics and wake vortex on the propulsive efficiency. Three-dimensional numerical analyses of full-active and semi-active flapping foils are carried out in this paper, in which the former focuses on different heave amplitudes and pitch amplitudes, and the latter concentrates on different spring stiffnesses. The analysis covers the full range of advance coefficient, which starts around 0 and ends at a thrust drop of 0. Firstly, the influence of the maximum AoA (α_max) on the efficiency and thrust coefficient of these two kinds of flapping foils is analyzed. The results show that for the small aspect ratio flapping foil in this paper, regardless of the full-active or semi-active form, the peak efficiency as high as 75% for both generally appears around α_max = 0.2 rad, while the peak thrust coefficient of 0.5 occurs near α_max = 0.3 rad. Then, by analyzing the wake flow field, it is found that the lower efficiency of larger α_max working points is mainly due to the larger vortex dissipation loss, while the lower efficiency of smaller α_max working points is mainly due to the larger friction loss of the foil surface. Furthermore, the plumpness of different AoA curves is compared and analyzed. It was found that, unlike the results of full-active flapping foils, the shape of the AoA curve of semi-active flapping foils with different spring stiffnesses is similar, and the relationship with efficiency is not strictly corresponding. This study is expected to provide guidance on both academics and industries in relevant fields. Full article

The increasing occurrence of dry and hot summers generates chronic water deficits that negatively affect tree radial growth. This phenomenon has been widely studied in natural stands of native species but not in commercial plantations of exotic tree species. In central Chile, where the species is increasingly planted, the dynamics of stone pine (Pinus pinea L.) growth under drought have been little explored. We studied the impact of drought on four stone pine plantations growing in central Chile. We sampled and cross-dated a total of 112 trees from four sites, measured their tree-ring width (RWL) series, and obtained detrended series of ring width indices (RWIs). Then, we calculated three resilience indices during dry years (Rt, resistance; Rc, recovery; and Rs, resilience), and the correlations between the RWI series and seasonal climate variables. We found the lowest growth rate (1.94 mm) in the driest site (Peñuelas). Wet conditions in the previous winter and current spring favored growth. In the wettest site (Pastene), the growth rates were high (4.87 mm) and growth also increased in response to spring thermal amplitude. Overall, fast-growing trees were less resilient than slow-growing trees. Drought reduced stone pine stem growth and affected tree resilience to hydric deficit. At the stand level, growth rates and resistance were driven by winter and spring precipitation. Fast-growing trees were more resistant but showed less capacity to recover after a drought. In general, stone pine showed a high post-drought resilience due to a high recovery after drought events. The fact that we found high resilience in non-native habitats, opens new perspectives for stone pine cropping, revealing that it is possible to explore new areas to establish the species. We conclude that stone pine shows a good acclimation in non-native, seasonally dry environments. Full article

Zuogong County is located in the southeast of Tibet, which is rich in hot spring geothermal resources, but its development and utilization degree are low, and the genetic mechanism of the geothermal system is not clear. Hydrogeochemical characteristics of geothermal water are of great significance in elucidating the genesis and evolution of geothermal systems, as well as the sustainable development and utilization of geothermal resources. The hydrogeochemical characteristics and genesis of the geothermal water in Zuogong County were investigated using hydrogeochemical analysis, a stable isotope (δD, δ¹⁸O) approach, and an inverse simulation model for water–rock reactions using the PHREEQC. The results indicated that the Zuogong geothermal system is a deep circulation heating type without a magmatic heat source. The chemical types present in the geothermal water from the Zuogong area are HCO₃ and HCO₃·SO₄, and the main cations are Na⁺ and Ca²⁺. The groundwater is replenished by atmospheric precipitation and glacier meltwater. The salt content of geothermal water mainly comes from the interaction between water and surrounding rocks during the deep circulation process. The reservoir temperature of geothermal water in Zuogong is 120–176 °C before mixing with non-geothermal water and drops to 62–98 °C after mixing with 58 to 79% of non-geothermal water. According to the proposed conceptual model, geothermal water mainly produces water–rock interaction with aluminosilicate minerals in the deep formation, while in shallow areas it interacts mainly with sulfate minerals. These findings contribute to a better understanding of the geothermal system in Zuogong County, Tibet. Full article

Hydrokinetic tidal energy is one of the few marine renewable energy resources with sufficiently mature technology for commercial exploitation. However, several parameters affect its exploitability, such as the minimum speed threshold, ambient turbulence levels, or tidal asymmetry, to name but a few. These parameters are particularly important in regions with lower mean speeds than those in first-generation sites, such as the North Sea. The Gulf of California is one of those regions. In this paper, a Delft3D Flexible Mesh Suite (Delft3D FM) model in barotropic configuration is set up over the Gulf of California using a flexible mesh with resolution varying from O (500 m) in the deep regions to O (10 m) in the coastal regions. A simulation is run over the year of 2020, with a tidal forcing of 75 components. The model is validated at four tidal gauge locations and four Acoustic Doppler Current profiler (ADCP) locations. The speed, U, and tidal power density ($TPD$) indicators used for the validation were the annual means, the annual means for speeds above the 0.5 m s⁻¹ threshold, the annual means of the spring tide maxima, and the annual maxima. The contour maps of the annual means, that is, the annual means for speeds above the $0.5$ m s⁻¹ threshold, allow us to identify tidal energy hot spots throughout the Gulf of California, particularly in the Great Island region (GIR). In this region, these hot spots have higher U and $TPD$ values, in agreement with previous studies. The patterns of circulation around Tiburón Island and San Esteban Island on the East, and Ángel de la Guarda Island and San Lorenzo Island on the West, the four islands in the region with the highest tidal energy potential, are also discussed while recognizing that Tiburón Channel, between Tiburón Island and San Esteban Island, has proved to be the best siting location, based on the technical results obtained so far. The hot spots sites are further characterized by computing the tidal asymmetry in these small regions, showing the locations of the sites with smallest asymmetry, which would be the best for tidal energy exploitation. The hot spots around San Esteban Island are particularly important because they have the largest $TPD$ in the GIR, with the model predicting a $TPD$ on the order of 500–1000 W m⁻². Here, complementary field measurements obtained with two ADCPs, close to San Esteban Island, one at 15 m depth, SEs (shallow region), and the other at 60 m depth, SEd (deep region), produced $TPD$s of 1200 W m⁻² and 400 W m⁻², respectively. The analysis of the vertical profiles and the tidal asymmetry over the vertical shows the importance of developing 3D models in future investigations. Full article

Since the 2005 discovery of the first enzyme capable of depolymerizing polyethylene terephthalate (PET), an aromatic polyester once thought to be enzymatically inert, extensive research has been undertaken to identify and engineer new biocatalysts for plastic degradation. This effort was directed toward developing efficient enzymatic recycling technologies that could overcome the limitations of mechanical and chemical methods. These enzymes are versatile molecules obtained from microorganisms living in various environments, including soil, compost, surface seawater, and extreme habitats such as hot springs, hydrothermal vents, deep-sea regions, and Antarctic seawater. Among various plastics, PET and polylactic acid (PLA) have been the primary focus of enzymatic depolymerization research, greatly enhancing our knowledge of enzymes that degrade these specific polymers. They often display unique catalytic properties that reflect their particular ecological niches. This review explores recent advancements in marine-derived enzymes that can depolymerize synthetic plastic polymers, emphasizing their structural and functional features that influence the efficiency of these catalysts in biorecycling processes. Current status and future perspectives of enzymatic plastic depolymerization are also discussed, with a focus on the underexplored marine enzymatic resources. Full article

Extremophiles, organisms thriving in extreme environments such as hot springs, deep-sea hydrothermal vents, and hypersaline ecosystems, have garnered significant attention due to their remarkable adaptability and biotechnological potential. This review presents recent advancements in isolating and characterizing extremophiles, highlighting their applications in enzyme production, bioplastics, environmental management, and space exploration. The unique biological mechanisms of extremophiles offer valuable insights into life’s resilience and potential uses in industry and astrobiology. Full article

In the context of global climate change and rapid population growth, more people in cities are facing heat threats. Although health risk assessment is critical for reducing heat-related morbidity and mortality, previous studies have not accurately identified the spatial details of heat risk levels on a fine scale within a complete framework. Therefore, this study developed a systematic method to conduct a spatially explicit assessment of heat-related health risks using local climate zones (LCZs) in Shanghai, China. First, multisource data were used to map LCZs in Shanghai. Second, a modified temperature-humidity index, population density, and ecological parameters were employed to construct a heat hazard–exposure–vulnerability framework for heat risk assessment. Finally, the differences in heat-related health risks among LCZs were compared. The results indicate that in Shanghai (1) the LCZ concept could help estimate the heat health risk (HHR) at the fine block level, and the area proportion of LCZ5 (open mid-rise buildings) accounted for more than 50%; (2) detailed spatial patterns of heat risk levels were similar in spring, summer, and autumn, but different in winter due to seasonal variations in heat hazards; and (3) the built LCZs usually had higher heat risk levels than natural land cover LCZs, with LCZ2 (compact mid-rise), LCZ3 (compact low-rise), and LCZ5 facing the most serious heat risks. The high-rise LCZs might reduce the heat risk level in hot seasons owing to shading effects but add to this risk in winter. These findings contribute to our understanding of HHR assessment. Full article

Cyanobacteria are widely distributed in natural environments including geothermal areas. A unicellular cyanobacterium, Thermosynechococcus, in a deeply branching lineage, develops thick microbial mats with other bacteria, such as filamentous anoxygenic photosynthetic bacteria in the genus Chloroflexus, in slightly alkaline hot-spring water at ~55 °C. However, Thermosynechococcus strains do not form cell aggregates under axenic conditions, and the cells are dispersed well in the culture. In this study, Thermosynechococcus sp. NK55a and Chloroflexus aggregans NBF, isolated from Nakabusa Hot Springs (Nagano, Japan), were mixed in an inorganic medium and incubated at 50 °C under incandescent light. Small cell aggregates were detected after 4 h incubation, the size of cell aggregates increased, and densely packed cell aggregates (100–200 µm in diameter) developed. Scanning electron microscopy analysis of cell aggregates found that C. aggregans filaments were connected with Thermosynechococcus sp. cells via pili-like fibers. Co-cultivation of C. aggregans with a pili-less mutant of Thermosynechococcus sp. did not form tight cell aggregates. Cell aggregate formation was observed under illumination with 740 nm LED, which was utilized only by C. aggregans. These results suggested that Chloroflexus filaments gather together via gliding motility, and piliated cyanobacterial cells cross-link filamentous cells to form densely packed cell aggregates. Full article

Thermostable amylases are among the most widely used and desirable enzymes in the food industry. Indeed, they guarantee faster reactions at high temperatures, enhanced substrate solubility and reduced microbial contamination and cooling costs. The objective of this work is to study the amylase activity of three strains of aerobic thermophilic bacteria isolated from the hot spring of Hammam Salhine, located in the wilaya of Skikda, Algeria. The three extracellular amylase-producing strains were subjected to the quantification of amylase activity. They presented medium to high activity, with significantly the best production for the AS1 strain with an activity of 10.62 ± 1.289 U (p > 0.05). Monitoring the kinetics of AS1 amylase activity reveals that the maximum enzymatic activity was reached after 52 h with a value of 53.665 ± 2.534 U. The maximum growth was reached after 54 h of fermentation at an OD of 0.865 ± 0.081 at 600 nm. The study of the effect of the variation in physicochemical parameters on the activity of AS1 amylase extract shows that the enzymatic activity was maximal at a temperature of 100 °C, a pH of 8.0 and in the absence of NaCl. The amylase extract of this strain showed significant thermostability at 100 °C. Full article