Search Results (6,525)

Cas9 with specialized temperature adaptations are essential for broadening the application of CRISPR-based genome editing across diverse biological contexts. Although Cas9 orthologs from thermophilic and mesophilic organisms have been characterized for high- and moderate-temperature applications, cold-active variants remain largely unexplored, limiting genome engineering in low-temperature systems such as aquaculture species. Here, we report the functional characterization of Fp2Cas9, a cold-adapted Type II-C nuclease from Flavobacterium psychrophilum. In vitro assays showed that Fp2Cas9 efficiently cleaves double-stranded DNA with a refined PAM requirement of 5′-SNAAAG-3′, and that its engineered sgRNA scaffold (sgRNA-V2) supports programmable DNA targeting. Notably, Fp2Cas9 retains 75% cleavage efficiency at 5 °C, approximately 2.5-fold higher than SpCas9 under the same conditions, but shows a marked reduction in activity at 35 °C. In vivo, a nuclear-localized variant (2NLS-Fp2Cas9) mediated efficient mutagenesis of the zebrafish slc45a2 gene, yielding ~60% indel frequencies and pigmentation-deficient phenotypes in ~43% of injected embryos. Collectively, these findings establish Fp2Cas9 as a cold-adapted Cas9 with reliable activity at low temperatures. This work adds a valuable tool to the CRISPR-Cas9 toolkit and may facilitate genome editing in cold-water organisms and other low-temperature systems. Full article

A novel metal oxide catalyst, PdO_x/CuO-ST, was prepared by calcining a Pd-embedded CuBTC precursor and compared with a PdO_x/CuO-SG catalyst synthesized via a sol–gel method. Characterization results indicated that in both catalysts, Pd species were incorporated into the CuO lattice, forming synergistic interactions that lowered the reduction temperature of CuO. The PdO_x/CuO-ST catalyst exhibited superior catalytic activity in the oxidative carbonylation of phenol to diphenyl carbonate when calcined at low temperature, which was attributed to well-dispersed Cu atoms and enhanced Pd–Cu integration. However, high-temperature calcination led to catalyst sintering and the formation of surface-adsorbed oxygen species, which reacted with PdO on CuO to generate inactive Pd_xCu_yO phases, thereby reducing the active Pd²⁺ content and degrading catalytic performance. Under optimized reaction conditions (100 °C, 7 h, Pd/phenol molar ratio = 1/425, and 6.6 MPa), the PdO_x/CuO-ST catalyst achieved a maximum phenol conversion of 79.5% and a diphenyl carbonate selectivity of 84.5%. Stability tests revealed that although the catalyst structure remained intact, deactivation occurred due to Pd leaching and the reduction in active PdO to metallic Pd⁰. Full article

Developing highly efficient and stable electrocatalysts from inexpensive and earth-abundant elements represents a significant advancement in overall water splitting (OWS). This study focuses on the synthesis and evaluation of palladium-modified cobalt–phosphorus (PdCoP) and cobalt–iron–phosphorus (PdCoFeP) coatings for use as electrocatalysts in hydrogen evolution (HER), oxygen evolution (OER) and overall water splitting (OWS) in alkaline media. A facile electroless plating method is adopted to deposit the CoP and CoFeP coatings onto a copper surface (Cu sheet), with sodium hypophosphite (NaH₂PO₂) acting as the reducing agent. Pd crystallites were incorporated on CoP and CoFeP coatings using the galvanic displacement method. This study details morphological characterization (using SEM, EDX, and XRD), as well as electrochemical activity testing, for both HER and OER using linear sweep voltammetry (LSV) at different temperatures. The stability of the catalysts for HER was evaluated using chronoamperometry (CA) and chronopotentiometry (CP). The results show that the Pd-modified CoFeP and CoP catalysts exhibited lower overpotentials of 207 and 227 mV, respectively, for HER and 396 mV for OER at a current density of 10 mA cm⁻² compared to the unmodified CoFeP and CoP catalysts. The innovation achieved in this study lies in combining a facile, low-cost deposition method (electroless plating followed by galvanic displacement) with a novel, highly effective ternary composition (PdCoFeP) that exploits synergistic electronic and morphological effects to achieve superior bifunctional performance for alkaline OWS, achieving a low cell voltage of 1.69 V at a current density of 10 mA cm⁻². Overall, this research demonstrates that these synthesized materials are promising candidates for sustainable and economical hydrogen production. Full article

Biodiesel is an alternative, sustainable, renewable, and environmentally friendly energy source, which has generated interest from the scientific community due to its low toxicity, rapid biodegradability, and zero carbon footprint. Biodiesel is a biofuel produced by the transesterification of triglycerides or the esterification of free fatty acids (FFA). Both reactions require catalysts with numerous active sites (basic, acidic, bifunctional, or enzymatic) for efficient biodiesel production. On the other hand, since the late 1990s, metal–organic frameworks (MOFs) have emerged as a new class of porous materials and have been successfully used in various fields due to their multiple properties. For this reason, MOFs have been used as heterogeneous catalysts or as a platform for designing active sites, thus improving stability and reusability. This literature review presents a comprehensive analysis of using MOFs as heterogeneous catalysts or supports for biodiesel production. The optimal parameters for transesterification/esterification are detailed, such as the alcohol/feedstock molar ratio, catalyst amount, reaction time and temperature, conversion percentage, biodiesel yield, fatty acid and water content, etc. Additionally, novel methodologies such as ultrasound and microwave irradiation for obtaining MOF-based catalysts are described. It is important to note that most studies have shown biodiesel yields >90% and multiple reuse cycles with minimal activity loss. The bibliographic analysis was conducted using the American Chemical Society (ACS) Scifinder^® database, the Elsevier B.V. Scopus^® database, and the Clarivate Analytics Web of Science^® database, under the institutional license of the Universidad Veracruzana. Keywords were searched for each section, generally limiting the document type to “reviews” and “journals,” and the language to English, and published between 2000 and 2025. Full article

Morphological plasticity (MP) is an essential strategy for plants in nutrient acquisition, disturbance alleviation, and community coexistence during environmental and climatic changes. However, to date, there has been little research concerning the MP for alpine–subalpine forests on the Qinghai–Tibet plateau. These forests are representative of the ectomycorrhizal (ECM) type, and morphological traits of these ECM roots, such as root tip lengths, diameters, and their adherent hyphal lengths and exploration types, have rarely been studied in the context of nutrient and environmental gradients. In this study, we examined the morphological traits of ECM roots for faxon fir (Abies fargesii var. faxoniana), which dominated in subalpine forests across nine elevations on the Eastern Qinghai–Tibet plateau. By quantifying ca. 90,000 root tips, the hyphal lengths of ectomycorrhizal extraradical mycelium (EEM, i.e., short- and long-distance exploration types) reached up to 1.1 × 10⁶ cm/m³ in soil, which decreased significantly due to gradually increasing altitude. In contrast, the variability of ECM root traits (diameter, length, and superficial area) was highly conserved along the altitudinal gradients, yet the root tip lengths were positively associated with soil protease enzyme activity. The increase in diameter and length of ECM root tips was climate-independent yet significantly associated with increasing root N concentration. In the studied forests, a long-distance exploration type of ECM hyphae was controlled by precipitation (p < 0.05), whereas the short-distance one was controlled by precipitation and temperature simultaneously. The EEM lengths of short- and long-distance exploration types were associated with high C concentration and low N concentration in host tree root tissues. Our findings demonstrated that MP expression in nutrient-foraging strategies for the dominant coniferous trees facilitates the adaptation to changing environments by specialized hyphal structures. In conclusion, ECM root tips and hyphal structures are two dimensions of functional traits linked to root N concentration in opposite ways, and their MP collectively ensures the temporal stability and resistance of subalpine forests on the Qinghai–Tibet plateau. These results provide new insights into ECM morphological traits and their adaptation in changing environments, which is valuable for understanding responses of subalpine forests to climate change. Full article

To address the issues of zero-valent iron Fe(0) passivation and limited nitrogen and phosphorus removal in constructed wetlands (CWs), this study investigated the enhancement effect of two carbon materials—activated carbon (AC) obtained through high-temperature pyrolysis and biochar (BC) obtained through low-temperature pyrolysis—when coupled with Fe(0). Four systems were set up: control (CW-C), Fe(0) alone (CW-Fe), Fe(0) with AC (CW-FeAC), and Fe(0) with BC (CW-FeBC). Evaluations covered wastewater treatment performance, microbial community structure, and functional gene abundance. Results showed that iron–carbon coupling significantly improved nitrogen and phosphorus removal, with the CW-FeAC system performing best, achieving 58% total nitrogen (TN) and 90% total phosphorus (TP) removal. This enhancement was attributed to AC’s high conductivity, which strengthened iron–carbon micro-electrolysis, accelerated Fe(0) corrosion, and enabled continuous Fe²⁺/Fe³⁺ release, supplying electrons for denitrification and phosphorus precipitation. Microbial analysis indicated that iron–carbon coupling markedly reshaped community structure, enriching key genera such as Thiobacillus (33.8%) and Geobacter (12.5%) in CW-FeAC. Functional gene analysis further confirmed higher abundances of denitrification (napA/narG→nirS→nosZ) and iron metabolism genes (feoA/feoB), suggesting enhanced nitrogen-iron cycling. This study clarifies the mechanisms by which iron–carbon coupling improves nitrogen and phosphorus performance in CWs and highlights the superiority of AC over BC in facilitating electron transfer and functional microorganism enrichment, providing a basis for the design of enhanced CW systems treating low-carbon-nitrogen-ratio wastewater, such as secondary effluent or lightly polluted surface water. Full article

High denitration efficiency and strong adaptability to flue gas temperature fluctuations are the core properties of the NH₃-SCR catalyst. In this study, Fe₂O₃ modification is used as a means to explore the mechanism of adding Fe₂O₃ to broaden the temperature range of the 6CeO₂-40MnO₂/TiO₂ catalyst during the preparation process. The results show that the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst exhibits excellent denitration performance, with a denitration efficiency higher than 90%. The temperature range is from 129 to 390 °C. N₂ selectivity and resistance to SO₂ and H₂O are good, and the denitration performance is significantly improved. When the Fe₂O₃ content is 6%, it promotes lattice shrinkage of TiO₂, improves its dispersion, refines the grain size, and increases the specific surface area of the catalyst. At the same time, Fe₂O₃ enhances the chemical adsorption of oxygen on the catalyst surface and increases the proportion of low-cost metal ions, thereby promoting electron transfer between active elements, generating more surface reactive oxygen species, increasing the oxygen vacancy content and adsorption sites for NO_x and NH₃, and significantly improving the redox performance of the catalyst. This effect is particularly conducive to the formation of strong acid sites on the catalyst surface. The NH₃-SCR reaction on the surface of the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst follows both the L-H and E-R mechanisms, with the L-H mechanism being dominant. Full article

This study investigated the impact of two different temperature regimes (high and low) on the chemical composition, antioxidant activity, and antidiabetic properties of mango jellies. Total phenolic content (TPC) and antioxidant capacity were assessed using the conventional 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the recently developed direct current (DC) polarographic method. Jellies prepared under low-temperature conditions contained higher TPC levels (82.0 ± 2.0 mg gallic acid equivalents (GAE)/kg jelly) and exhibited stronger antioxidant activity (65.0 ± 2.2 ascorbic acid equivalents (AAE)/100 g jelly by DPPH; 12.40 × 10⁻⁶ mol reduced Hg(II)/g jelly by DC polarography). Antidiabetic evaluation revealed that the low-temperature jelly significantly inhibited both α-amylase and α-glucosidase activity. Thermal analysis further confirmed distinct structural behavior between low- and high-temperature products. This novel processing approach—combining mild heating (55 °C), vacuum treatment, and reduced sugar content (40%) without pectin addition—proved effective in preserving bioactive compounds and functionality. Notably, this is the first report applying DC polarography to assess antioxidant capacity in fruit jellies, highlighting its potential as a robust tool in functional food research. Full article

In recent years CO₂ reforming of methane has attracted great interest as it produces high CO/H₂ ratio syngas suitable for the synthesis of higher hydrocarbons and oxygenated derivatives since it is a way for disposing and recycling two greenhouse gases with high environmental impact, CH₄ and CO₂, and because it is regarded as a potential route to store and transmit energy due to its strong endothermic effect. Along with noble metals, all the group VIII metals except for osmium have been studied for catalytic CO₂ reforming of methane. It was found that the catalytic activity of Ni, though lower than those of Ru and Rh, was higher than the catalytic activities of Pt and Pd. Although noble metals have been proven to be insensitive to coke, the high cost and restricted availability limit their use in this process. It is therefore valuable to develop stable Ni-based catalysts. In this contribution, we show how their activity and coking resistivity are greatly related to the size and dispersion of Ni particles. Well-dispersed Ni nanoparticles were achieved by multistep impregnation on a mesoporous silica support, namely SBA-15, obtained through a sol-gel method, using acetate as a nickel precursor and keeping the Ni loading between 5% and 11%. Significant catalytic activity was obtained at temperatures as low as 450 °C, a temperature well below their deactivation temperature, i.e., 700 °C. For the pre-reduced samples, a CO₂ conversion higher than 99% was obtained at approximately 680 °C. As such, their deactivation by sintering and coke formation was prevented. To the best of our knowledge, no Ni-based catalysts with complete CO₂ conversion at temperatures lower than 800 °C have been reported so far. Full article

The response of tomato plants, Ailsa Craig and the carotenoid mutant tangerine, to five days of treatment by low light intensity at normal and low temperature with respect to the photosynthetic performance as well as their capacity to recover after three days under normal conditions was evaluated. Tangerine plants are characterized by defective prolycopene isomerase (CRTISO) and accumulate tetra-cis lycopene instead of all-trans lycopene. The gas exchange parameters were evaluated on intact plants and the pigment content in leaves was estimated. The photosynthetic competence of photosystem II (PSII) and photosystem I (PSI) and the effectiveness of the energy dissipation were assessed by pulse-amplitude-modulated (PAM) fluorometry. The abundance of reaction center proteins of PSII and PSI was estimated by immunoblotting. The application of low light alone or low light and low temperature reduced the chlorophyll content in both types of plants, which was more strongly expressed in Ailsa Craig. The net photosynthetic rate and photochemical activities of PSII and PSI were negatively affected by low light and much more strongly decreased when low light was applied at low temperature. The low-light-induced increase in excitation pressure on PSII and the effectiveness of non-photochemical quenching were not temperature-dependent. The negative effect of the combined treatment in tangerine was more strongly expressed in comparison with Ailsa Craig with respect to the abundance of reaction center proteins of both photosystems. Most probably, the differential photosynthetic response of the carotenoid mutant tangerine and Ailsa Craig to the combined treatment by low light and low temperature is related to the accumulation of tetra-cis-lycopene instead of all-trans-lycopene. Full article

A notable decline in the frequency of sea fog inflows and an increase in low-cloud ceiling height were observed following the construction of the Saemangeum Seawall west of the Gunsan Airport, an area traditionally prone to frequent sea fog events. To the mechanisms underlying these changes, a numerical experiment was conducted using the Weather Research and Forecasting model. An 11-m-high seawall was used as a physical barrier, and an elevated sea surface temperature (SST) was established within the enclosed area to simulate realistic post-construction conditions. The model successfully reconstructed sea fog occurrences, and the cloud–water mixing ratio effectively captured the spatial distribution of sea fog. Deviations from the control experiment showed a consistent pattern of reduced cloud–water mixing ratios near the surface and enhanced concentrations at high levels. Decreased buoyancy frequency in the surface layer enhanced atmospheric instability, inducing upward motion and intensified condensation activity. Increases in the turbulence kinetic energy within the planetary boundary layer (TKE within the PBL), vertical wind shear, and temperature further corroborated the reduction in sea fog and enhanced stratus formation. These findings indicate that the increased SST and seawall significantly influence the modification of the sea fog structure and its inflow dynamics. Full article

Monitoring indoor air quality is vital for health, as CO₂ is a major pollutant. An automated system that accurately forecasts CO₂ levels can optimize HVAC management, preventing sudden increases and reducing energy waste while maintaining occupant comfort. Traditionally, such systems require extensive datasets collected over months to train algorithms, making them computational expensive and inefficient. To address this limitation, an adaptive IoT-based platform has been developed, leveraging a limited set of recent data to forecast CO₂ trends. Tested in a real-world setting, the system analyzed parameters such as physical activity, temperature, humidity, and CO₂ to ensure accurate predictions. Data acquisition was performed using the Smartex WWS T-shirt for physical activity data and the UPSense UPAI3-CPVTHA environmental sensor for other measurements. The chosen sensor devices are wireless and minimally invasive, while data processing was carried out on a low-power embedded PC. The proposed forecasting model adopts an innovative approach. After a 5-day training period, a Generative Adversarial Network enhances the dataset by simulating a 10-day training period. The model utilizes a Generative Adversarial Network with a Long Short-Term Memory network as the generator to predict future CO₂ values based on historical data, while the discriminator, also a Long Short-Term Memory network, distinguishes between actual and generated CO₂ values. This approach, based on Conditional Generative Adversarial Networks, effectively captures data distributions, enabling more accurate multi-step probabilistic forecasts. In this way, the framework maintains a Root Mean Square Error of approximately 8 ppm, matching the performance of our previous approach, while reducing the need for real training data from 10 to just 5 days. Furthermore, it achieves accuracy comparable to other state-of-the-art methods that typically requires weeks or even months of training. This advancement significantly enhances computational efficiency and reduces data requirements for model training, improving the system’s practicality for real-world applications. Full article

Silica aerogels are highly attractive due to their outstanding properties, including their low density, ultralow thermal conductivity, large porosity, high optical transparency, and strong sorption activity. However, their inherent brittleness has limited widespread applications. Constructing a robust, highly porous three-dimensional network is critical to achieving the desired mechanical properties in aerogels. In this study, we introduce a novel synthesis route for fabricating lightweight and mechanically strong aerogels by incorporating poly(ethylene-co-vinyl alcohol) (EVOH) through thermally induced phase separation (TIPS). EVOH exhibits upper critical solution temperature (UCST) behavior in a mixture of isopropanol (IPA) and water, which can be utilized to reinforce the silica skeletal structure. Robust aerogels were prepared via the sol–gel process and TIPS method, followed by supercritical CO₂ drying, yielding samples with bulk densities ranging from 0.136 to 0.200 g/cm³. N₂ physisorption analysis revealed a mesoporous structure, with the specific surface area decreasing from 874 to 401 m²/g as EVOH content increased from 0 to 80 mg/mL. The introduced EVOH significantly enhanced mechanical performance, raising the flexural strength and compressive strength to 0.545 MPa and 18.37 MPa, respectively—far exceeding those of pure silica aerogel (0.098 MPa and 0.74 MPa). This work demonstrates the effectiveness of the TIPS strategy for developing high-strength, low-density silica aerogels with well-preserved porosity. Full article

Bacterial infections are a major complication in chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS), where mucus accumulation and pH fluctuations further hinder treatment. Nanostructured systems such as carbon dots (CDs) are increasingly investigated as antimicrobial agents due to their scalability, low cost, and biocompatibility, compared to conventional antibiotics. Here, CDs were synthesized by a one-step microwave-assisted method at three reaction temperatures (130 °C, 170 °C, and 185 °C, named LT-CDs, MT-CDs, HT-CDs, respectively) to explore the effect of carbonization on their structure and function. TEM, Raman, and FTIR analyses were employed to investigate the size and distribution of carbon groups. UV–vis confirmed distinct pH-dependent spectral responses, and mucoadhesion studies revealed stronger and more stable interactions for MT-CDs. Biological assays demonstrated high biocompatibility across all samples on lung fibroblasts, while antimicrobial tests highlighted a selective effect against Staphylococcus aureus, due to ROS generation. Overall, MT-CDs represented the best compromise in terms of size, functionalization, biocompatibility, mucoadhesion, and antimicrobial activity, emerging as promising nanoplatforms for respiratory infection management in COPD and ARDS. Full article

Bacterial cellulose (BC) is a type of biomass composed entirely of cellulose. This characteristic favors the presence of a multitude of active sites, which facilitate the exchange of heavy metals present in polluting effluents. Upon contact with water contaminated with metals such as chromium, arsenic, and lead, among others, this biomass offers a potential solution to the environmental problem of industrial pollutants in water. This is particularly pertinent given the well-documented harmful effects of heavy metals in aquatic ecosystems. In this context, the objective is to determine the impact of temperature on Cr (IV) adsorption using bacterial cellulose biomass as an adsorbent, under different temperature scenarios, similar to the conditions of discharge of contaminated effluents into rivers, lagoons, and wetlands. In this study, the biomass was previously characterized through FTIR and SEM images, and isothermal models were subsequently evaluated along with batch adsorption kinetics. The findings demonstrate that bacterial cellulose biomass has great potential for Cr (VI) removal at various temperatures, with an adsorption capacity of 140 mg/g at high temperatures and a reduction of up to 125 mg/g at low temperatures. The findings of this study constitute a valuable contribution to decision-making when considering the expansion of these treatment processes, facilitating this task by offering a comparative analysis of effluent discharge conditions in relation to various scenarios involving contaminated liquid temperatures. The use of this biomaterial in an environmental sustainability initiative focused on water resource conservation is a very promising prospect. Full article