Dominant Pathway Research Articles

Earthworms reduce nutrient loss from loess soil slopes under simulated rain

Burrowing, feeding, and casting activities of earthworms affect nutrient cycling and hydrological processes that take place in sloping lands. However, the effects exerted by earthworms on nutrient losses associated with runoff and sediment during rain remains unclear, particularly in the Loess Plateau, where soil erosion and nutrient loss have led to severe environmental issues. In this study, our purpose was to quantify the effects exerted by the anecic earthworm species, Metaphire guillelmi, on nutrient loss via runoff and erosion in loess soil slopes. Six artificial grass slopes (mesocosms, 15°), comprising three with earthworms (100 individuals m−2) for 28 days, and three without earthworms, were subjected to simulated rain (90 mm h−1) for 60 min. Our results indicated that earthworms had (i) increased the content of NO3–-N from 8.1 to 151.8 mg kg−1 and OP from 51.0 to 71.8 mg kg−1, but decreased the content of OC from 6.6 to 5.2 g kg−1, TN from 0.76 to 0.62 g kg−1, TP from 0.73 to 0.68 g kg−1 and NH4+-N from 3.7 to 2.4 mg kg−1 at surface 2 cm soil; (ii) increased water-stable macroaggregates from 45.1 to 48.3% and soil saturated water conductivity from 0.07 to 0.28 mm min−1, and (iii) greatly reduced the cumulative runoff from 65.7 to 15.3 mm and sediment occurance from 0.44 to 0.16 kg m−2 on slopes. Consequently, earthworm activities decreased runoff-associated nutrients (decreased NH4+-N from 19.5 to 2.8 mg m−2, NO3–-N from 108.2 to 26.2 mg m−2, and SP from 2.2 to 0.1 mg m−2) loss by 75.8–96.2%, and sediment-bound nutrient (decreased OC from 2.4 to 0.8 g m−2, TN from 0.3 to 0.1 g m−2, TP from 0.3 to 0.1 g m−2) loss by 63.8–68.5%. Hierarchical partitioning and variation partitioning analyses showed that runoff and sediment yields and their interaction with the soil physical characteristics were the dominant pathways via which earthworms regulated nutrient loss during rainfall events. This study highlights the importance of soil fauna in regulating erosion and nutrient loss in the Loess Plateau, and indicates that these factors should be considered in future water and soil conservation management.

Uncovering PM2.5 transport trajectories and sources at district within city scale

To continuously improve air quality, it is necessary to carry out fine management of air pollution prevention and control. However, research into regional transport of PM2.5 at a smaller spatial scale such as district is limited. In this study, a novel combined method was constructed to simulate and identify the regional transport trajectories and potential sources of PM2.5 concentrations at district scale, based on a hybrid model that integrates the Bayesian maximum entropy (BME) model, Weather Research and Forecast (WRF) and backward trajectory model. Take Tianjin as an example, an analysis of the transport trajectories showed that the air masses from northwest and southwest were the dominant atmospheric transport pathway in all seasons except summer. The number of transport trajectories from northwest and southwest accounted for 42.41% and 40.75% of the total number of transport trajectories. Despite the dominant wind direction in winter was northwest, it can be beneficial to atmospheric transport. This was because northwest trajectories were the long-range pathways, corresponding to fast-moving air masses that facilitate the dispersion of pollutants. On contrast, it is noteworthy that the southwest trajectories were the short-range pathways, resulting in limited diffusion and unfavorable conditions. The major potential cities that were likely contributors of PM2.5 (Weighted Concentration-Weighted Trajectory (WCWT) values greater than 40 μg m−3) were situated in the southwest. Furthermore, the inter-district transport results indicated that the primary direction of PM2.5 transport in Tianjin was also from south to north. It is critical that the current layout of Tianjin is adjusted in a timely manner through relocating or phasing out, as the majority of industrial enterprises with severe air pollution in Tianjin are located in the southern districts. This method of combining BME, WRF and backward trajectory can be used for atmospheric environment planning in other similar city and district-scale around the world. It also provides useful insights to policy makers when they formulate pollutants prevention control policies.

Analysis of ortho-phthalates and other plasticizers in select organic and conventional foods in the United States.

ortho-phthalates and other plasticizers impart flexibility to plastics in food production, processing, and packaging; food consumption is a dominant plasticizer exposure pathway. Lower molecular weight ortho-phthalates are being replaced in plastic products due to toxicity concerns, but toxic hazards of and exposures to replacementortho-phthalates and other plasticizers are poorly understood. We measured 12 ortho-phthalates and 9 other plasticizers in conventional and organic U.S. food products to assess magnitude and profiles of contamination. We measured plasticizers in 34 vegetable oils, 10 milks, 18 infant formulas, and 9 cheese powders from macaroni kits using gas chromatography coupled with mass spectrometry (GC-MS). We analyzed plastic packaging composition using FTIR spectroscopy. We detected eight ortho-phthalates and three alternatives ((1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), diethylhexyl terephthalate (DEHT), and diisobutyl adipate (DIBA). Diethylhexyl phthalate (DEHP) was measured in all 71 products. DEHT had the highest concentration of any plasticizer (>10,000 ng/g in three oils). Oils had the highest total plasticizer (median = 770 ng/g, max = 14,900 ng/g) and milk the lowest (median = 88 ng/g, max = 120 ng/g). Organic milk and refined oils had higher median plasticizer levels than conventional. Refined oils had significantly lower concentrations than unrefined oils. Maximum contributors for every category were non-ortho-phthalates: DEHT (powdered infant formula and oils) and DIBA (cheese powder, milk and liquid formula). Plasticizers were not detected in packaging except epoxidized soybean oil in liquid formula lids. Human exposure to plasticizers is a significant public health concern. Nevertheless, sources of such exposures are poorly characterized. This study adds valuable information for estimating legacy and alternative plasticizer exposures from foods. The method developed for measuring DINCH, DINP and DIDP broadens the range of plasticizers other researchers may analyze in future work. The profiles of plasticizer contamination varied depending on the food type. We also document that food processing may be a source of plasticizer contamination in foods.

Recent increase in low complexity polygenomic infections and sialic acid-independent invasion pathways in Plasmodium falciparum from Western Gambia

BackgroundThe malaria parasite Plasmodium falciparum utilizes multiple alternative receptor-ligand interactions for the invasion of human erythrocytes. While some P. falciparum clones make use of sialic acid (SA) residues on the surface of the human glycophorin receptors to invade the erythrocyte, others use alternative receptors independent of sialic acid residues. We hypothesized that over the years, intensified malaria control interventions and declining prevalence in The Gambia have resulted in a selection of parasites with a dominant invasion pathways and ligand expression profiles.MethodsBlood samples were collected from 65 malaria-infected participants with uncomplicated malaria across 3 years (2015, 2016, and 2021). Genetic diversity was determined by genotyping the merozoite surface protein 2 (msp2) polymorphic gene of P. falciparum. Erythrocyte invasion phenotypes were determined using neuraminidase, trypsin, and chymotrypsin enzymes, known to cleave different receptors from the surface of the erythrocyte. Schizont-stage transcript levels were obtained for a panel of 6 P. falciparum invasion ligand genes (eba175, eba181, Rh2b, Rh4, Rh5, and clag2) using 48 successfully cultured isolates.ResultsThough the allelic heterozygosity of msp2 repeat region decreased as expected with reduced transmission, there was an increase in infections with more than a single msp2 allelotype from 2015 to 2021. The invasion phenotypes of these isolates were mostly SA independent with a continuous increase from 2015 to 2021. Isolates from 2021 were highly inhibited by chymotrypsin treatment compared to isolates from 2015 and 2016. Higher invasion inhibition for 2021 isolates was further obtained following erythrocyte treatment with a combination of chymotrypsin and trypsin. The transcript levels of invasion ligand genes varied across years. However, levels of clag2, a rhoptry-associated protein, were higher in 2015 and 2016 isolates than in 2021 isolates, while Rh5 levels were higher in 2021 compared to other years.ConclusionsOverall, these findings suggest increasing mixed infections with an increase in the use of sialic-acid independent invasion pathways by P. falciparum clinical isolates in the Western part of Gambia.Graphical

Chemical Fate of Oils on Indoor Surfaces: Ozonolysis and Peroxidation.

Unsaturated triglycerides found in food and skin oils are reactive in ambient air. However, the chemical fate of such compounds has not been well characterized in genuine indoor environments. Here, we monitored the aging of oil coatings on glass surfaces over a range of environmental conditions, using mass spectrometry, nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) techniques. Upon room air exposure (up to 17 ppb ozone), the characteristic ozonolysis products, secondary ozonides, were observed on surfaces near the cooking area of a commercial kitchen, along with condensed-phase aldehydes. In an office setting, ozonolysis is also the dominant degradation pathway for oil films exposed to air. However, for indoor enclosed spaces such as drawers, the depleted air flow makes lipid autoxidation more favorable after an induction period of a few days. Forming hydroperoxides as the major primary products, this radical-mediated peroxidation behavior is accelerated by indoor direct sunlight, but the initiation step in dark settings is still unclear. These results are in accord with radical measurements, indicating that indoor photooxidation facilitates radical formation on surfaces. Overall, many intermediate and end products observed are reactive oxygen species (ROS) that may induce oxidative stress in human bodies. Given that these species can be widely found on both food and household surfaces, their toxicological properties are worth further attention.

FlgM is required to evade NLRC4-mediated host protection against flagellated Salmonella.

Salmonella enterica serovar Typhimurium is a leading cause of gastroenteritis worldwide and a deadly pathogen in children, immunocompromised patients, and the elderly. Salmonella induces innate immune responses through the NLRC4 inflammasome, which has been demonstrated to have distinct roles during systemic and mucosal detections of flagellin and non-flagellin molecules. We hypothesized that NLRC4 recognition of Salmonella flagellin is the dominant protective pathway during infection. To test this hypothesis, we used wild-type, flagellin-deficient, and flagellin-overproducing Salmonella to establish the role of flagellin in mediating NLRC4-dependent host resistance during systemic and mucosal infections in mice. We observed that during the systemic phase of infection, Salmonella efficiently evades NLRC4-mediated innate immunity. During mucosal Salmonella infection, flagellin recognition by the NLRC4 inflammasome pathway is the dominant mediator of protective innate immunity. Deletion of flgM results in constitutive expression of flagellin and severely limits systemic and mucosal Salmonella infections in an NLRC4 inflammasome-dependent manner. These data establish that recognition of Salmonella's flagellin by the NLRC4 inflammasome during mucosal infection is the dominant innate protective pathway for host resistance against the enteric pathogen and that FlgM-mediated evasion of the NLRC4 inflammasome enhances virulence and intestinal tissue destruction.

Characterizing Mg2+ Conduction in Metal-Organic Frameworks

Next generation solid-state materials for fast ion conduction have the potential to revolutionize battery technology. Metal-organic frameworks (MOF) are a promising material for achieving this goal. Given their structural diversity and complexity, design of efficient MOF-based ion conductors can be accelerated by detailed understanding and quantitative prediction of ion conductivity. To this end, the chemical behavior and transport properties of an Mg(TFSI)2/DME electrolyte system inside Mg-MOF-74 were studied by a combination of computational and experimental methods.The dominant minimum energy pathway (MEP) for Mg2+ conduction inside Mg-MOF-74 was found to be “solvent hopping” mechanism, with an energy barrier of 4.4 kcal/mol.However, due to the polycrystalline nature of solid-state materials, specifically MOF-74 in our case, grain boundary effects need to be taken into consideration, which is complicated by challenges in grain boundary characterization, as well as modeling of ensemble transport properties. To address these issues, we developed an approach for modeling ion transport at grain boundaries and predicting their contribution to conductivity. In particular, Mg2+ conduction in Mg-MOF-74 thin film was studied as a representative system. Using computational techniques and guided by experimental data, we investigated the structural details of MOF grain boundary interfaces to determine accessible Mg2+ transport pathways. Computed transport kinetics were input into a simplified model of the MOF nanocrystal, which combined ion transport in bulk structure and at grain boundaries. The model was able to predict Mg2+ conductivity in MOF-74 thin film within chemical accuracy (<1 kcal/mol difference for apparent activation energy), validating our approach. The results indicate that Mg2+ conduction in MOF-74 is inhibited due to strong Mg2+ binding at grain boundaries. Only favorable alignments of the grain boundary interface allow for fast Mg2+ transport through MOF and contribute notably to ion conductivity. The relative scarcity (~0.1% frequency) of these favorable alignments results in a reduction of conductivity by 2-3 orders of magnitude, illustrating the large impact of the grain boundary contribution. Grain boundary structure and its interaction with ions are critical for a molecular-level understanding of solid-state ion transport and quantitative prediction of conductivity.Our work provides a computation-aided synergistic platform for quantifying the role of grain boundaries in mediating ion transport, which can serve as a complementary characterization tool for the solid-state ion conductor community and providing insights for MOFs’ application in Mg battery area.

Planktonic microbial community and biological metabolism in a subtropical drinking water river-reservoir system

To understand the dynamics of planktonic microbial community and its metabolism processes in subtropical drinking water river-reservoir system with lower man-made pollution loading, this study selected Dongzhen river-reservoir system in Mulan Creek as object to investigate spatial-temporal characteristics of community profile and functional genes involved in biological metabolism, and to analyze the influence of environmental factors. The results indicated that Proteobacteria and Actinobacteria were the most diverse phyla with proportion ranges of 9%–80% in target system, and carbohydrate metabolism (5.76-7.12 × 10−2), amino acid metabolism (5.78-7.21 × 10−2) and energy metabolism (4.07-5.17 × 10−2) were found to be the dominant pathways of biological metabolism. Although there were variations in biological properties both spatially and temporally, seasonal variation had a greater influence on microbial community and biological metabolism, than locational differences. Regarding the role of environmental factors, this study revealed that microbial diversity could be affected by multiple abiotic factors, with total organic carbon, total phosphorus and temperature being more influential (absolute value of standardized regression weights >2.13). Stochastic processes dominated the microbial community assembly (R2 of neutral community model = 0.645), while niche-based processes differences represented by nutrients, temperature and pH level played secondary roles (R > 0.388, P < 0.01). Notably, the synergistic influences among the environmental factors accounted for the higher percentages of community variation (maximum proportion up to 17.6%). Additionally, pH level, temperature, and concentrations of dissolved oxygen, carbon and nitrogen were found to be the significant factors affecting carbon metabolism pathways (P < 0.05), yet only total organic carbon significantly affected on nitrogen transformation (P < 0.05). In summary, the microbial profile in reservoir is not completely dominated by that in feeding river, and planktonic microbial community and its metabolism in subtropical drinking water river-reservoir system are shaped by multiple abiotic and biotic factors with underlying interactions.

Ball milling enhanced magnetic corn straw biochar for peroxyacetic acid activation towards efficient degradation of sulfadiazine

A novel heterogeneous catalyst of ball-milling magnetic corn straw biochar (BMCBC) was the first time synthesized and employed to activate peroxyacetic acid (PAA) for efficiently degrading sulfadiazine (SDZ). The superior porous structure and the magnetic Fe3O4 of BMCBC guaranteed its higher activation efficiency than that of CBC. The results showed that 93% of SDZ was removed by PAA/BMCBC system within 60 min. Solution pH, CO32-, NO3- and Cl- concentrations were the crucial environmental factors affecting the degradation process of SDZ. The electron paramagnetic resonance (EPR), quenching experiments, and Raman spectra analysis indicated that •OH and R-O• were the main contributors to SDZ degradation. The transformed products (TPs) generated in PAA/BMCBC system were less toxic compared to those of SDZ. Three degradation pathways of SDZ were proposed and hydroxylation and S-N bond breakage by •OH and R-O• attacking were the dominant degradation pathways of SDZ in PAA/BMCBC system. Also, PAA/BMCBC system built in this study exhibited excellent removal performance for SDZ in actual waters including river water (84.32%), lake water (73.95%), tap water (93.30%) and drinking water (91.29%). Additionally, BMCBC exhibited satisfactory environmental safety in a wide pH range (from 3 to 11) with low leaching levels of Fe. The good magnetic sensitivity of BMCBC enabled it to be easily collected and it performed outstanding sustainable activation performance for PAA even after five reuse cycles. This study developed a promising method for antibiotics (e.g., SDZ) elimination, in addition to that the resource utilization of agricultural wastes (e.g., corn straw) was achieved.

Reductive dechlorination of trichloroethene by sulfided microscale zero-valent iron in fresh and saline groundwater: Reactivity, pathways, and selectivity

S/mZVI is a promising material for groundwater remediation due to its excellent properties. However, the reactivity and electron selectivity toward target contaminant are critical. Thus, this study investigated the effect of complex groundwater chemistries (Milli-Q water, fresh groundwater and saline groundwater) on the reactivity of S/mZVI toward trichloroethylene (TCE), dechlorination pathway, hydrogen evolution kinetic, electron efficiency and aging behaviors. Results showed that sulfidation appreciably increased the reactivity and electron selectivity. The major degradation product of TCE dechlorination by S/mZVI was acetylene, which was consistent with TCE dechlorination by β-elimination. Moreover, reductive β-elimination was still the dominant dechlorination pathway for the application of S/mZVI in three groundwater conditions. However, the rates and the quantities of major products from TCE degradation varied significantly. S/mZVI in saline groundwater can maintain the reactivity towardTCE due to the protection of Fe0 by Fe3O4 deposited on the surface. Thus, the higher TCE removal efficiency and less hydrogen accumulation resulted in the greatest electron efficiency (4.3–79.2%). Overall, S/mZVI was more effective for the application in saline groundwater. This study proved insight into the comprehensive evaluation and implications for the application of S/mZVI based technologies in saline contaminated groundwater.

A DFT study on the mechanism of acetaldehyde generation during vinyl acetate synthesis from gas-phase ethylene acetoxylation on Pd/Au (100) surface

Acetaldehyde (CH3CHO) is an important by-product in the reaction of ethylene to vinyl acetate (VAC). However, the mechanism of the generation of CH3CHO has been little studied. In this paper, we designed a reaction network for the possible generation of acetaldehyde from intermediate species on Pd/Au catalysts, including three reaction paths. Stable adsorption configurations of the species involved in each elementary reaction were identified by Density Functional Theory (DFT) calculations and the charge changes on the catalyst surface during the adsorption process as well as the structural parameter changes of the adsorption configurations were compared. Based on this, we calculated the kinetic parameters on three reaction paths and combined with Kinetic Monte Carlo (KMC) simulations to found the dominant path and rate-determining step to help understand the mechanism of acetaldehyde generation on the surface of Pd/Au (100). Results suggest that species involved in the reactions are adsorbed mainly on Pd-Au bridge sites, Pd top sites, and Pd-Pd intermediate vacancies and species structure changes after adsorption. CHCH, CH2CH, and CH3CH could all generate CHxCHO by reacting with O species or OH species, and the energy barrier for reactions with O species are all lower than those for reactions with OH species. The dominant pathway for acetaldehyde generation on Pd/Au (100) surface is CH2CH2 → CH2CH→ CH2CHO → CH3CHO and the ethylene dehydrogenation elementary reaction is the rate-determining step.

Numerical investigation of pressure and H2O dilution effects on NO formation and reduction pathways in pure hydrogen MILD combustion

Pure hydrogen moderate or intense low-oxygen dilution (MILD) combustion offers a potential solution to meet low NO emission needs while achieving rapid decarbonization for gas turbines. This paper reports a numerical investigation of the pressure (1–25 atm) and H2O dilution (0–60%vol, including its physical and chemical effects) influences on NO formation and reduction pathways in opposed-flow pure hydrogen diffusion MILD combustion, where the present NO sub-pathway analysis method is also evaluated. Results show that, the present NO sub-pathway analysis method with Glarborg2018 can respectively predict thermal NO, prompt NO, NO formed via NNH and N2O-intermediate, and NO reduced via CHi and H reburning reasonably well. In pure hydrogen MILD combustion, NO emission reaches its peak with the pressure up to about 6 atm due to more NO formed via N2O-intermediate, and then decreases as the pressure is further raised, which is mainly attributed to less NO formation via NNH and more NO reduction by H radicals, finally causing the dominant NO formation pathway to transform from NNH to N2O-intermediate at high pressure. The addition of H2O, mainly because of its chemical effect to inhibit the NNH and N2O-intermediate pathways via the channels NNH + O → NO and N2O + H/O → NO, results in further NO emission reduction. The top NO contributor is changed from NNH to N2O-intermediate with H2O dilution at atmospheric pressure, while at high pressure, NO formation is invariably dominated by the N2O-intermediate pathway even when H2O is added up to 60%vol. NO reduction, which is initiated by the channel NO+H(+M)⇌HNO(+M), behaves more actively at high pressure, constituting 21% of the total NO produced at 25 atm, while its importance is weakened with H2O dilution.

Human health risk-based soil generic assessment criteria of representative perfluoroalkyl acids (PFAAs) under the agricultural land use in typical Chinese regions

Perfluoroalkyl acid substances (PFAAs), such as perfluorobutanoic acid (PFBA), perfluorobutanoic sulfonic acid (PFBS), perfluorooctane acid (PFOA) and perfluoroooctane sulfonic acid (PFOS) are frequently detected in the global environment and can cause potential health hazards even at low levels. In this study, quantitative human health risk assessment was undertaken to derive soil generic assessment criteria (GAC) for four PFAAs under the agricultural land scenario in the evaluated Chinese regions, which considered multiple exposure pathways including vegetables consumption, dermal absorption, ingestion of soil and dust, and exposure from non-soil sources. It is showed that the calculated GAC for four PFAAs in Guangdong and Shandong Provinces were less stringent than those in Zhejiang and Jiangsu Provinces, and Shanghai City, owing to the low exposure from non-soil sources in former two provinces. In addition, GAC of PFOS were the most stringent in the range of 0.28–0.50 μg kg−1 in the studied regions, followed by PFOA (1.36–2.20 μg kg−1), PFBA (42.59–68.03 μg kg−1) and PFBS (474.59–749.60 μg kg−1), mainly attributable to significantly more stringent toxicological values of PFOA and PFOS. Correspondingly, the potential health hazards exist for PFOA in the studied regions except Guangdong Province, and PFOS only in Zhejiang and Jiangsu Provinces as indicated by the hazard quotients ranging from 1.04 to 19.49, but no health hazards are identified for PFBA and PFBS. The dominant exposure pathway was found to be consumption of vegetables and attached soil for PFBA and PFBS, contributing to more than 93% of the total exposure, compared to 49.91–76.69% for PFOA and PFOS due to significant exposure from non-soil sources levels. Overall, this study provides a technical reference on how to derive scientifically justifiable soil GAC for representative PFAAs for maintaining and assessing soil quality and food safety internationally under the agricultural land use.

An observation-based, reduced-form model for oxidation in the remote marine troposphere

The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of the formation and loss of many air pollutants, but direct OH observations are sparse. We develop and evaluate an observation-based proxy for short-term, spatial variations in OH (ProxyOH) in the remote marine troposphere using comprehensive measurements from the NASA Atmospheric Tomography (ATom) airborne campaign. ProxyOH is a reduced form of the OH steady-state equation representing the dominant OH production and loss pathways in the remote marine troposphere, according to box model simulations of OH constrained with ATom observations. ProxyOH comprises only eight variables that are generally observed by routine ground- or satellite-based instruments. ProxyOH scales linearly with in situ [OH] spatial variations along the ATom flight tracks (median r2 = 0.90, interquartile range = 0.80 to 0.94 across 2-km altitude by 20° latitudinal regions). We deconstruct spatial variations in ProxyOH as a first-order approximation of the sensitivity of OH variations to individual terms. Two terms modulate within-region ProxyOH variations-water vapor (H2O) and, to a lesser extent, nitric oxide (NO). This implies that a limited set of observations could offer an avenue for observation-based mapping of OH spatial variations over much of the remote marine troposphere. Both H2O and NO are expected to change with climate, while NO also varies strongly with human activities. We also illustrate the utility of ProxyOH as a process-based approach for evaluating intermodel differences in remote marine tropospheric OH.

Excitation of NH Stretching Modes in Aromatic Molecules: o-Toluidine and α-Methylbenzylamine.

Selectively excited o-toluidine and α-methylbenzylamine have been studied with quasi-classical trajectory procedures to determine the extent and timescales of intramolecular energy flow. The initial excitation is in the stretching mode of the para-CH bond, and its flow is initiated by interaction with an argon atom. Energy flow to the NH stretching mode is the dominant relaxation pathway, and its effectiveness is enhanced strongly by the methyl-NH interaction. Energy flow characteristics in both molecules are similar, but the flow is more effective in o-toluidine than in α-methylbenzylamine because the methyl group bonded to the benzene ring exerts stronger perturbation on the energy-flow pathway than the group bonded to the side chain. The relaxation of the initially excited CH completes on a timescale of several picoseconds, but the main part of energy flow to the NH occurs on a subpicosecond scale. In o-toluidine, carbon-carbon overtone modes lead to ring-CC bonds gaining and transporting more energy than high-frequency CH bonds, but they all gain far less energy than the NH stretching mode.

GBP2 promotes M1 macrophage polarization by activating the notch1 signaling pathway in diabetic nephropathy.

Diabetic nephropathy (DN) is one of the most common diabetic complications, which has become the primary cause of end-stage renal disease (ESRD) globally. Macrophage infiltration has been proven vital in the occurrence and development of DN. This study was designed to investigate the hub genes involved in macrophage-mediated inflammation of DN via bioinformatics analysis and experimental validation. Gene microarray datasets were obtained from the Gene Expression Omnibus (GEO) public website. Integrating the CIBERSORT, weighted gene co-expression network analysis (WGCNA) and DEGs, we screened macrophage M1-associated key genes with the highest intramodular connectivity. Subsequently, the Least Absolute Shrinkage and Selection Operator (LASSO) regression was utilized to further mine hub genes. GSE104954 acted as an external validation to predict the expression levels and diagnostic performance of these hub genes. The Nephroseq online platform was employed to evaluate the clinical implications of these hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to elucidate the dominant biological functions and signal pathways. Finally, we conducted experiments to verify the role of GBP2 in M1 macrophage-mediated inflammatory response and the underlying mechanism of this role. Sixteen DEGs with the highest connectivity in M1 macrophages-associated module (paleturquoise module) were determined. Subsequently, we identified four hub genes through LASSO regression analysis, including CASP1, MS4A4A, CD53, and GBP2. Consistent with the training set, expression levels of these four hub genes manifested memorably elevated and the ROC curves indicated a good diagnostic accuracy with an area under the curve of greater than 0.8. Clinically, enhanced expression of these four hub genes predicted worse outcomes of DN patients. Given the known correlation between the first three hub genes and macrophage-mediated inflammation, experiments were performed to demonstrate the effect of GBP2, which proved that GBP2 contributed to M1 polarization of macrophages by activating the notch1 signaling pathway. Our findings detected four hub genes, namely CASP1, MS4A4A, CD53, and GBP2, may involve in the progression of DN via pro-inflammatory M1 macrophage phenotype. GBP2 could be a promising prognostic biomarker and intervention target for DN by regulating M1 polarization.

Ni-Co alloy catalyst derived from NixCoy/MgAl2O4 via exsolution method for high coke resistance toward dry reforming of methane

The dry reforming methane (DRM) reaction, which directly utilizes the two major greenhouse gases as reactants and produces syngas (a mixture of H2 and CO), is a promising method to achieve carbon neutrality. In this study, we developed a series of Ni–Co alloy catalysts with varying ratios using the exsolution method and explored the optimal Ni/Co ratio for DRM. By incorporating Co as a secondary metal and precisely controlling its proportion, the catalysts exhibited improved activation balance in CH4 and CO2, excellent resistance to coking, and the efficiency of the reaction pathway. Notably, the Ni4Co1 catalyst exhibited excellent coke resistance with the lowest coking rate of 0.2 μgcoke·gcat−1h−1, which was only 0.34% of the monometallic Ni catalyst. The origin of coke resistance of catalysts was investigated through in-situ DRIFT and found that the appropriate ratio of Co leads to the formate-intermediate dominant pathway that is more favorable for anti-coking. Furthermore, the catalysts exhibited reversible exsolution properties, as confirmed by cyclic of calcination–reduction. The findings of this study offer valuable insights into the fabrication of high-performance DRM catalysts utilizing the exsolution-driven alloying technique.

Quantifying the Role of Simultaneous Transformation Pathways in the Fate of the Novel Aquatic Herbicide Florpyrauxifen-Benzyl.

Predicting the fate of organic compounds in the environment is challenging due to the inability of laboratory studies to replicate field conditions. We used the intentionally applied aquatic herbicide florpyrauxifen-benzyl (FPB) as a model compound to investigate the contribution of multiple transformation pathways to organic compound fate in lakes. FPB persisted in five Wisconsin lakes for 5-7 days with an in-lake half-life of <2 days. FPB formed four transformation products, with the bioactive product florpyrauxifen persisting up to 30 days post-treatment. Parallel laboratory experiments showed that FPB degrades to florpyrauxifen via base-promoted hydrolysis. Hydroxy-FPB and hydroxy-florpyrauxifen were identified as biodegradation products, while dechloro-FPB was identified as a photoproduct. Material balance calculations using both laboratory rates and field product concentrations demonstrated that hydrolysis (∼47% of loss), biodegradation (∼20%), sorption (∼13%), and photodegradation (∼4%) occurred on similar timescales. Furthermore, the combined results demonstrated that abiotic and plant-catalyzed hydrolysis of FPB to florpyrauxifen, followed by biodegradation of florpyrauxifen to hydroxy-florpyrauxifen, was the dominant transformation pathway in lakes. This study demonstrates how combined field and laboratory studies can be used to elucidate the role of simultaneous and interacting pathways in the fate of organic compounds in aquatic environments.

Calculation of ATP production rates using the Seahorse XF Analyzer.

Oxidative phosphorylation and glycolysis are the dominant ATP-generating pathways in mammalian metabolism. The balance between these two pathways is often shifted to execute cell-specific functions in response to stimuli that promote activation, proliferation, or differentiation. However, measurement of these metabolic switches has remained mostly qualitative, making it difficult to discriminate between healthy, physiological changes in energy transduction or compensatory responses due to metabolic dysfunction. We therefore present a broadly applicable method to calculate ATP production rates from oxidative phosphorylation and glycolysis using Seahorse XF Analyzer data and empirical conversion factors. We quantify the bioenergetic changes observed during macrophage polarization as well as cancer cell adaptation to in vitro culture conditions. Additionally, we detect substantive changes in ATP utilization upon neuronal depolarization and T cell receptor activation that are not evident from steady-state ATP measurements. This method generates a single readout that allows the direct comparison of ATP produced from oxidative phosphorylation and glycolysis in live cells. Additionally, the manuscript provides a framework for tailoring the calculations to specific cell systems or experimental conditions.

Transcriptome profiling analysis of uterus during chicken laying periods

The avian eggshell is formed in the uterus. Changes in uterine function may have a significant effect on eggshell quality. To identify the vital genes impacting uterine functional maintenance in the chicken, uteri in three different periods (22W, 31W, 51W) were selected for RNA sequencing and bioinformatics analysis. In our study, 520, 706 and 736 differentially expressed genes (DEGs) were respectively detected in the W31 vs W22 group, W51 vs W31 group and W51 vs W22 group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated DEGs were enriched in the extracellular matrix, extracellular region part, extracellular region, extracellular matrix structural constituent, ECM receptor interaction, collagen-containing extracellular matrix and collagen trimer in the uterus (P < 0.05). Protein–protein interaction analysis revealed that FN1, LOX, THBS2, COL1A1, COL1A2, COL5A1, COL5A2, POSTN, MMP13, VANGL2, RAD54B, SPP1, SDC1, BTC, ANGPTL3 might be key candidate genes for uterine functional maintenance in chicken. This study discovered dominant genes and pathways which enhanced our knowledge of chicken uterine functional maintenance.