Waters (China)

Flavonoids exhibit high structural complexity not only from their diverse cores and substitutions but also from glycosylation with various glycans, leading to numerous isomeric species. This study employed cyclic ion mobility mass spectrometry (cIM-MS) to achieve high-resolution separation of flavonoid and flavonoid glycoside isomers with subtle structural differences. A multipass cIM strategy featuring adjustable drift path lengths significantly enhanced both resolution and operational flexibility. Notably, multiple ion mobility peaks were frequently observed for individual pure compounds, which were identified as charge-site isomers arising primarily from sodium adduction at distinct molecular sites. Computational chemistry and collision cross section (CCS) analysis were integrated to elucidate the three-dimensional configurations corresponding to these different mobility peaks. The results reveal that sodium ions, by coordination with multiple electronegative oxygen atoms within the molecule, stabilize specific gas-phase conformations, leading to distinct CCS values resolvable by ion mobility spectrometry. This work advances the understanding of charge-site isomerism by providing atomic-level insights into metal ion-molecule interactions. It also establishes an integrated cIM-MS and computational modeling framework, which substantially enhances analytical depth for complex isomeric systems.

Fires disrupt ecosystems, release carbon, and reduce carbon uptake, which increases atmospheric CO2 concentration, warms the atmosphere, and fosters more frequent and intense fires. Quantifying postfire recovery is crucial for understanding the adaptability and resilience of ecosystems to fire disturbances. Observations from satellite-derived active fire (~1-km) and Gross Primary Productivity (GPP) products reveal that Australia experiences extensive fires annually, reducing vegetation productivity. Here we analyze the post-fire GPP recovery trajectories of 1.7 × 106 fire-affected pixels (or 1.5 × 106 km2) in Australia between 2011 and 2019, of which 1.3 × 106 pixels (1.2 × 106 km2) experienced a single fire (single-fire pixels), and 0.4 × 106 pixels (0.3 × 106 km2) experienced two or more fires (multiple-fire pixels). We found that Australia's postfire GPP recovery was strong and rapid. 88% of single-fire pixels recovered to 135% of the prefire level in an average of 2.3 years, whereas 86% of multiple-fire pixels recovered to 115% of the prefire level in an average of 1.2 years. NonForest ecosystems (e.g., grasslands, shrublands, and savannas) exhibited a higher postfire recovery magnitude (138% for single-fire pixels and 115% for multiple-fire pixels) compared to Forest (110% for single-fire pixels and 108% for multiple-fire pixels). This rapid and robust postfire GPP recovery is significantly influenced by postfire precipitation, fire (i.e., fire frequency, intensity) and fire severity (damage, impacts; a metric of resistance of terrestrial ecosystems to fire). Specifically, higher fire severity and higher postfire precipitation have a positive impact on postfire recovery, whereas increased fire frequency has a negative impact. Furthermore, fire dynamics have a smaller role in the long-term interannual continental GPP changes than climate or land-use changes, as strong and rapid GPP recovery offsets the short-term fire-induced GPP losses.

In federal learning, the frequent interaction of model parameters between the central server and terminals leads to high communication overhead. Especially when the communication capabilities of terminals are weak and they are sensitive to energy consumption, optimizing communication overhead has become a key challenge. This paper comprehensively considers model parameter compression and communication algorithm optimization and proposes a power control method based on probabilistic quantization. Firstly, the MSE performance of parameter compression based on probabilistic quantization under non-perfect communication links is derived. Then, methods for minimizing the transmit power of terminals in the cases of equal and unequal transmit power are proposed respectively. Finally, the effectiveness of the proposed method is verified through numerical simulations. This method enables local terminals to reduce the local model parameters to be transmitted through quantization compression and dynamically adjust the transmit power according to network and channel conditions.

Bell pepper (Capsicum annuum L.) is a commercially important and nutritionally rich vegetable crop in the Solanaceae family. Alkaline stress (AS) can disrupt growth, metabolism, and, particularly, nutritional quality. This study aims to evaluate the role of iron oxide nanoparticles (FeNP) in mitigating AS and enhancing plant growth and metabolic functions by conducting experiments under controlled greenhouse conditions with four main treatments: AS (irrigating plants with alkaline salts mixture solution); FeNP (foliar application of Fe3O4 nanoparticles at 100 mg L−¹); AS + FeNP (integrated treatment of AS and FeNP); and CK (control). The results clearly demonstrated that the AS treatment negatively affects plant biomass, photosynthetic attributes, membrane integrity, carbohydrate metabolism, and the balance of the antioxidant system. Additionally, key phenolic and flavonoid compounds decreased under the AS, indicating a detrimental effect on the plant’s secondary metabolites. In contrast, the application of FeNP under the AS not only improved growth and photosynthetic attributes but also enhanced membrane integrity and restored antioxidant balance. This restoration was driven by the accumulation of sugars (glucose, fructose, sucrose) and starch, along with key carbohydrate metabolism enzymes—sucrose phosphate synthase (SPS), sucrose synthase (SuSy), neutral invertase (NI), and vacuolar invertase (VI)—and their associated gene expression. The correlation analysis further revealed a tight regulation of carbohydrate metabolism at both enzymatic and transcript levels in all tissue types, except for SPS in the roots. Furthermore, the AS + FeNP treatment resulted in increased levels of key phenolics (dihydrocapsaicin, capsaicin, p-coumaric acid, sinapic acid, p-OH benzoic acid, p-OH benzaldehyde, and ferulic acid) and flavonoid compounds (dihydroquercetin, naringenin, kaempferol, dihydrokaempferol, and quercetin) compared to the AS treatment, thus suggesting that these secondary metabolites likely contribute to the stabilization of cellular structures and membranes, ultimately supporting improved physiological functions and resilience under stress. In conclusion, the application of FeNP demonstrate potential in enhancing the resilience of bell pepper plants against the AS by improving growth, carbohydrate metabolism, and the levels of secondary metabolites.

Rapid and accurate methods for tracing and identifying the origin of lamb are crucial for ensuring food authenticity and quality. This study developed a precise traceability method to determine the origin of lamb by integrating rapid evaporative ionization mass spectrometry (REIMS) with multivariate statistical analysis. Lamb samples from Xilin Gol, Ordos, and Hulun Buir ranches were identified by REIMS fingerprinting within 1 min. The discrimination model based on lipid molecular features achieved the highest recognition accuracy of 99.14% compared to models based on small-molecule metabolites (91.59%), fatty acids (98.52%), and full-spectrum molecules (98.49%). Furthermore, differential analyses were conducted to assess lamb meat from different origins and feeding methods (grazing versus feedlot) using REIMS fingerprints. Lamb products from the Xilin Gol ranch exhibited significantly lower glycerophosphate (PA) content compared to lambs from other regions, while grazing resulted in significantly lower PA content in lamb meat compared to those fed in feedlots. Additionally, meat from grazed lambs had significantly higher unsaturated fatty acid content, providing molecular evidence for its superior nutritional quality and distinct flavor profile compared to the lambs from feedlot systems. REIMS is a promising tool for rapid discrimination of lamb meat from different origins and feeding systems with high accuracy, offering valuable technical support for lamb origin traceability and quality assessment.

Cryptosporidium parvum is a zoonotic parasite of the intestine and poses a threat to human and animal health. However, it is difficult to obtain a large number of oocysts for genome sequencing using in vitro culture. To address this challenge, we employed the strategy of whole-genome amplification of 10 oocysts followed by long-read sequencing and obtained a high-quality genome assembly of C. parvum IIdA19G1 subtype isolated from a pre-weaning calf with diarrhea. The assembled genome was 9.13 Mb long and encompassed eight chromosomes with six capped by telomeric sequences at one or both ends. In total, 3,915 protein-coding genes were predicted, exhibiting a high completeness with 98.2% single-copy BUSCO genes. To our current knowledge, this represents the first chromosome-level genome assembly of C. parvum achieved through the combined use of whole-genome amplification of 10 oocysts and long-read sequencing. This achievement not only advances our understanding of the genomic landscape of this zoonotic intestinal parasite, but also provides valuable resources for comparative genomics and evolutionary analyses within the Cryptosporidium clade.

In November 2023, a 24-hour study was conducted on the dynamic changes in water transparency and suspended solids in Nanhu Lake, a typical urban landscape lake in the plain river network region during winter. The results indicated that in November, Nanhu Lake had an average water depth of 2.98 meters and an average water transparency of 44.48 cm, with a mean water temperature of 15.69°C. Turbidity values ranged from 20.35 to 54.51NTU, with an average of 33.62 NTU. The average values for DO, EC, ORP, and TDS were 9.57 mg/L, 450.89 mV, 157.04 mV, and 225.31 mg/L, respectively, with no significant differences in major water quality indicators across different regions. The 24-hour water transparency variation and patterns at the three sampling stations in Nanhu Lake showed considerable differences, influenced by various factors. Transparency was lowest during the daytime from 06:30 to 18:30, with relatively higher suspended solids content. The content of suspended solids ranged from 13.40 to 39.20 mg/L, with an average of 26.04 mg/L, showing significant variation across different regions. Sampling station one was notably affected by disturbances from docked boats. In terms of composition, inorganic and organic suspended solids accounted for 83% and 17%, respectively, with inorganic particles being predominant. The median particle size of suspended solids in Nanhu Lake ranged from 4.77 to 7.83 μm, with an average size of 6.15 μm. The particle size distribution was 75% for particles ⪅10 μm, 18% for particles between 10-20 μm, and 7% for particles ⪆20 μm. The suspended particles in the surface water of Nanhu Lake were finer than those in the bottom layer, making them more difficult to settle naturally once resuspended.

Mating type (sex) plays a crucial role in regulating sexual reproduction in most extant eukaryotes. One of the functions of mating types is ensuring self-incompatibility to some extent, thereby promoting genetic diversity. However, heterothallic mating is not always the best mating strategy. For example, in low-density populations or specific environments, such as parasitic ones, species may need to increase the ratio of potential mating partners. Consequently, many species allow homothallic selfing (i.e., self-fertility or intraclonal mating). Throughout the extensive evolutionary history of species, changes in environmental conditions have influenced mating strategies back and forth. However, the mechanisms through which mating-type recognition regulates sexual reproduction and the dynamics of mating strategy throughout evolution remain poorly understood. In this study, we show that the Cip1 protein is responsible for coupling sexual reproduction initiation to mating-type recognition in the protozoal eukaryote Tetrahymena thermophila. Deletion of the Cip1 protein leads to the loss of the selfing-avoidance function of mating-type recognition, resulting in selfing without mating-type recognition. Further experiments revealed that Cip1 is a regulatory subunit of the Cdk19-Cyc9 complex, which controls the initiation of sexual reproduction. These results reveal a mechanism that regulates the choice between mating and selfing. This mechanism also contributes to the debate about the ancestral state of sexual reproduction.