Performance of large language models on benign prostatic hyperplasia frequently asked questions.

BACKGROUND: Benign prostatic hyperplasia (BPH) is a common condition, yet it is challenging for the average BPH patient to find credible and accurate information about BPH. Our goal is to evaluate and compare the accuracy and reproducibility of large language models (LLMs), including ChatGPT-3.5, ChatGPT-4, and the New Bing Chat in responding to a BPH frequently asked questions (FAQs) questionnaire. METHODS: A total of 45 questions related to BPH were categorized into basic and professional knowledge. Three LLM-ChatGPT-3.5, ChatGPT-4, and New Bing Chat-were utilized to generate responses to these questions. Responses were graded as comprehensive, correct but inadequate, mixed with incorrect/outdated data, or completely incorrect. Reproducibility was assessed by generating two responses for each question. All responses were reviewed and judged by experienced urologists. RESULTS: All three LLMs exhibited high accuracy in generating responses to questions, with accuracy rates ranging from 86.7% to 100%. However, there was no statistically significant difference in response accuracy among the three (p > 0.017 for all comparisons). Additionally, the accuracy of the LLMs' responses to the basic knowledge questions was roughly equivalent to that of the specialized knowledge questions, showing a difference of less than 3.5% (GPT-3.5: 90% vs. 86.7%; GPT-4: 96.7% vs. 95.6%; New Bing: 96.7% vs. 93.3%). Furthermore, all three LLMs demonstrated high reproducibility, with rates ranging from 93.3% to 97.8%. CONCLUSIONS: ChatGPT-3.5, ChatGPT-4, and New Bing Chat offer accurate and reproducible responses to BPH-related questions, establishing them as valuable resources for enhancing health literacy and supporting BPH patients in conjunction with healthcare professionals.

Mechanistic Insight for Disinfection Byproduct Formation Potential of Peracetic Acid and Performic Acid in Halide-Containing Water.

Peracetic acid (PAA) and performic acid (PFA) are two major peroxyacid (POA) oxidants of growing usage. This study reports the first systematic evaluation of PAA, PFA, and chlorine for their disinfection byproduct (DBP) formation potential in wastewater with or without high halide (i.e., bromide or iodide) concentrations. Compared with chlorine, DBP formation by PAA and PFA was minimal in regular wastewater. However, during 24 h disinfection of saline wastewater, PAA surprisingly produced more brominated and iodinated DBPs than chlorine, while PFA effectively kept all tested DBPs at bay. To understand these phenomena, a kinetic model was developed based on the literature and an additional kinetic investigation of POA decay and DBP (e.g., bromate, iodate, and iodophenol) generation in the POA/halide systems. The results show that PFA not only oxidizes halides 4-5 times faster than PAA to the corresponding HOBr or HOI but also efficiently oxidizes HOI/IO- to IO3-, thereby mitigating iodinated DBP formation. Additionally, PFA's rapid self-decay and slow release of H2O2 limit the HOBr level over the long-term oxidation in bromide-containing water. For saline water, this paper reveals the DBP formation potential of PAA and identifies PFA as an alternative to minimize DBPs. The new kinetic model is useful to optimize oxidant selection and elucidate involved DBP chemistry.

First Discovery of Iodinated Polyfluoroalkyl Acids by Nontarget Mass-Spectrometric Analysis and Iodine-Specific Screening Algorithm.

Per- and polyfluoroalkyl acids (PFAAs) including polyfluoroalkyl carboxylic acids and polyfluoroalkyl sulfonic acids are a large category of crucial environmental pollutants of global concern. Besides known PFAAs, numerous unknown species may exist in the environment, urgently needing discovery and characterization. This study implemented nontarget analysis for a group of novel PFAA pollutants, viz., iodinated PFAAs (I-PFAAs) in wastewater from a fluorochemical manufacturing park by liquid chromatography-high-resolution mass spectrometry in combination with an iodine-specific data-processing algorithm. The algorithm took into account the diagnostic fragment iodine ion (I-) together with carbon and sulfur isotopologue distributions. In total, 18 I-PFAA formulas involving 21 congeners were identified. Semiquantification was conducted, and the total concentrations of I-PFAAs were 1.9-274.7 µg/L, indicating severe pollution of I-PFAAs in the wastewater. The determined concentrations along with predicted environmental behaviors and toxicities demonstrate that I-PFAAs merit further in-depth investigation. The analytical method including the instrumental analysis and data-processing algorithm can be extended to screening and identification of I-PFAAs in other matrices. Furthermore, the analysis results for the first time provide recognition on the occurrence, distribution features, and pollution status of I-PFAAs in the environment.

Nontarget Analysis and Comprehensive Characterization of Iodinated Polyfluoroalkyl Acids in Wastewater and River Water by LC-HRMS with Cascade Precursor-Ion Exclusions and Algorithmic Approach.

Poly- and perfluoroalkyl acids (PFAAs) are a large family of widespread contaminants of worldwide concern and well-known as "forever chemicals". Direct emission of PFAAs from the fluorochemical industry is a crucial source of PFAA pollutants in the environment. This study implemented nontarget analysis and comprehensive characterization for a category of new PFAA contaminants, i.e., iodinated PFAAs (IPFAAs), in fluorochemical industry wastewater and relevant contaminated river water by liquid chromatography-high-resolution mass spectrometry with a cascade precursor ion exclusion (PIE) strategy and in-house developed data extraction and processing algorithms. A total of 26 IPFAAs (including 2 isomers of an IPFAA) were found and identified with tentative molecular structures. Semiquantification of the IPFAAs was implemented, and the total concentrations of IPFAAs were 0.16-285.52 and 0.15-0.17 µg/L in wastewater and river water, respectively. The high concentrations in association with the predicted ecotoxicities and environmental behaviors demonstrate that these IPFAAs are worthy of more concern and further in-depth research. The cascade PIE strategy along with the data extraction and processing algorithms can be extended to nontarget analysis for other pollutants beyond IPFAAs. The nontarget identification and characterization outcomes provide new understanding on the environmental occurrence and pollution status of IPFAAs from a comprehensive perspective.

Genome-Wide Identification of HSF Gene Family in Kiwifruit and the Function of AeHSFA2b in Salt Tolerance.

Heat shock transcription factors (HSFs) play a crucial role in regulating plant growth and response to various abiotic stresses. In this study, we conducted a comprehensive analysis of the AeHSF gene family at genome-wide level in kiwifruit (Actinidia eriantha), focusing on their functions in the response to abiotic stresses. A total of 41 AeHSF genes were identified and categorized into three primary groups, namely, HSFA, HSFB, and HSFC. Further transcriptome analysis revealed that the expression of AeHSFA2b/2c and AeHSFB1c/1d/2c/3b was strongly induced by salt, which was confirmed by qRT-PCR assays. The overexpression of AeHSFA2b in Arabidopsis significantly improved the tolerance to salt stress by increasing AtRS5, AtGolS1 and AtGolS2 expression. Furthermore, yeast one-hybrid, dual-luciferase, and electrophoretic mobility shift assays demonstrated that AeHSFA2b could bind to the AeRFS4 promoter directly. Therefore, we speculated that AeHSFA2b may activate AeRFS4 expression by directly binding its promoter to enhance the kiwifruit's tolerance to salt stress. These results will provide a new insight into the evolutionary and functional mechanisms of AeHSF genes in kiwifruit.

Preparation of magnetic biochar and its catalytic role in degradation of Cu-EDTA by heterogeneous Fenton reaction.

In this study, magnetic biochar (Fe-BC) was synthesized from phoenix tree leaves and FeSO4·7H2O by impregnation-pyrolysis method, and was used to activate H2O2 to degrade Cu-EDTA. The effects of preparation parameters on the degradation of Cu-EDTA by Fe-BC/H2O2 system were investigated by degradation experiments and characterization methods (SEM, BET, FTIR, XRD and XPS). The results showed that the magnetic biochar prepared under the pyrolysis temperature of 400 °C, pyrolysis time of 3 h and iron content of 3 wt% had the best catalytic activity. Within 120 min, the breaking efficiency of Cu-EDTA binding, precipitation efficiency of Cu2+ and removal efficiency of TOC could reach 78.48, 71.65 and 46.54% at the conditions of adding 1.0 g/L magnetic biochar and 25 mM H2O2 and the iron dissolution was only 0.32 mg/L. The characterization results and comparison experiments demonstrated that the catalytic effect of magnetic biochar not only depends on the transfer of electrons to H2O2 by the loaded iron oxides, but also the active oxygen functional groups (OFGs) and persistent free radicals (PFRs) contained on the surface can transfer electrons to H2O2 or even dissolved oxygen to produce an amount of hydroxyl radicals (·OH) and superoxide anion radicals (O2·-).

Evaluation of HZX-960, a novel DCN1-UBC12 interaction inhibitor, as a potential antifibrotic compound for liver fibrosis.

Liver fibrosis is a very common health problem and currently lacks effective treatments. Cullin RING E3 ligases (CRLs) regulate the turnover of ∼20% of mammalian cell proteins. Neddylation, the process by which NEDD8 is covalently attached to cullin proteins through sequential enzymatic reactions, is critical for the activation of CRLs and was recently found to be elevated in liver fibrosis. NEDD8-activating enzyme E1-specific inhibition led to the reduced liver damage characterized by decreased apoptosis, inflammation, and fibrosis. However, the relevance of a co-E3 ligase, DCN1, in liver fibrosis remains unclear. Here, a novel and potent DCN1-UBC12 interaction inhibitor HZX-960 was discovered with an IC50 value of 9.37 nmol/L, which could inhibit the neddylation of cullin3. Importantly, we identified that HZX-960 treatment could attenuate transforming growth factor ß-induced liver fibrotic responses by reducing the deposition of collagen I and α-smooth muscle actin, and upregulating cellular NF-E2-related factor 2, hemeoxygenase 1, and NADPH quinone oxidoreductase-1 levels in two hepatic stellate cell lines. Additionally, DCN1 was shown to be unregulated in CCl4-induced mice liver tissue, and liver fibrotic signaling in mice was reduced by HZX-960. Therefore, our data demonstrated that HZX-960 possessed anti-liver fibrosis ability and that DCN1 may be a potential therapeutic target for liver fibrosis treatment.

Flurochloridone induces responses of free radical reactions and energy metabolism disorders to BRL-3A cell.

Flurochloridone (FLC), a wildly used herbicide, could induce hepatotoxicity after long-term exposure to male rat, in addition to its reactive oxygen species (ROS)-dependent reproductive toxicity. The hepatotoxicity effect and mechanism was investigeted using 1, 10 and 100 µmol L-1 FLC treated BRL-3A liver cell in this study. The function of mitochondrial respiration, glycolysis rate and real time ATP production rate are determined by seahorse XF analyzer, and the bio-transformers of FLC, intermediates of TCA cycle and glycolysis, and related amino acids are determined and identified by [U-13C] Glucose metabolic flux technology based on UPLC-HRMS. The mRNA expression of cytochrome P450s and the key regulatory enzymes of glucose metabolism and γ- glutamyl cycle pathway. The protein expressions of protein kinase B (AKT) and glycogen synthase kinase-3 beta (GSK-3ß) were determined. The results show dechlorination and glutathione (GSH) conjugate products of FLC are predominant bio-transformmers after 24 h treatment in BRL-3A cell. FLC could enhance glycolysis function and inhibit mitochondrial aerobic respiratory, which is accompanied by the decreased total ATP level and ATP produced rate. Increased glucose-6-phosphate, fructose-6-phosphate, pyruvate and lactate levels, and elevated level of GSH and its precursor 5-glutamate-cysteine (γ-Glu-Cys) are observed in FLC treated cells, which indicates that energy metabolism dysfunction and GSH accumulation could be potentially mediated by activating γ- Glutamyl cycle pathway. Conclusively, FLC induced hepatotoxicity could be potentially related to some free radical reactions, including inhibiting mitochondrial function, glucose metabolism via glycolysis, regulating γ- glutamyl cycle pathway to promote reactive oxygen species (ROS) level, and then induced cell apoptosis by inhibiting AKT/GSK-3ß signal.

Critical Roles of Polycomb Repressive Complexes in Transcription and Cancer.

Polycomp group (PcG) proteins are members of highly conserved multiprotein complexes, recognized as gene transcriptional repressors during development and shown to play a role in various physiological and pathological processes. PcG proteins consist of two Polycomb repressive complexes (PRCs) with different enzymatic activities: Polycomb repressive complexes 1 (PRC1), a ubiquitin ligase, and Polycomb repressive complexes 2 (PRC2), a histone methyltransferase. Traditionally, PRCs have been described to be associated with transcriptional repression of homeotic genes, as well as gene transcription activating effects. Particularly in cancer, PRCs have been found to misregulate gene expression, not only depending on the function of the whole PRCs, but also through their separate subunits. In this review, we focused especially on the recent findings in the transcriptional regulation of PRCs, the oncogenic and tumor-suppressive roles of PcG proteins, and the research progress of inhibitors targeting PRCs.

Glucocorticoid Regulates the Synthesis of Porcine Muscle Protein through m6A Modified Amino Acid Transporter SLC7A7.

The occurrence of stress is unavoidable in the process of livestock production, and prolonged stress will cause the decrease of livestock productivity. The stress response is mainly regulated by the hypothalamic-pituitary-adrenal axis (HPA axis), which produces a large amount of stress hormones, namely glucocorticoids (GCs), and generates a severe impact on the energy metabolism of the animal body. It is reported that m6A modification plays an important role in the regulation of stress response and also participates in the process of muscle growth and development. In this study, we explored the effect of GCs on the protein synthesis procession of porcine skeletal muscle cells (PSCs). We prove that dexamethasone affects the expression of SLC7A7, a main amino acid transporter for protein synthesis by affecting the level of m6A modification in PSCs. In addition, we find that SLC7A7 affects the level of PSC protein synthesis by regulating the conduction of the mTOR signaling pathway, which indicates that the reduction of SLC7A7 expression may alleviate the level of protein synthesis under stress conditions.

Larval zebrafish display dynamic learning of aversive stimuli in a constant visual surrounding.

Balancing exploration and anti-predation are fundamental to the fitness and survival of all animal species from early life stages. How these basic survival instincts drive learning remains poorly understood. Here, using a light/dark preference paradigm with well-controlled luminance history and constant visual surrounding in larval zebrafish, we analyzed intra- and intertrial dynamics for two behavioral components, dark avoidance and center avoidance. We uncover that larval zebrafish display short-term learning of dark avoidance with initial sensitization followed by habituation; they also exhibit long-term learning that is sensitive to trial interval length. We further show that such stereotyped learning patterns is stimulus-specific, as they are not observed for center avoidance. Finally, we demonstrate at individual levels that long-term learning is under homeostatic control. Together, our work has established a novel paradigm to understand learning, uncovered sequential sensitization and habituation, and demonstrated stimulus specificity, individuality, as well as dynamicity in learning.

Photochemical Phase Transitions Enable Coharvesting of Photon Energy and Ambient Heat for Energetic Molecular Solar Thermal Batteries That Upgrade Thermal Energy.

Discovering physicochemical principles for simultaneous harvesting of multiform energy from the environment will advance current sustainable energy technologies. Here we explore photochemical phase transitions-a photochemistry-thermophysics coupled regime-for coharvesting of solar and thermal energy. In particular, we show that photon energy and ambient heat can be stored together and released on demand as high-temperature heat, enabled by room-temperature photochemical crystal↔liquid transitions of engineered molecular photoswitches. Integrating the two forms of energy in single-component molecular materials is capable of providing energy capacity beyond that of traditional solar or thermal energy storage systems based solely on molecular photoisomerization or phase change, respectively. Significantly, the ambient heat that is harvested during photochemical melting into liquid of the low-melting-point, metastable isomer can be released as high-temperature heat by recrystallization of the high-melting-point, parent isomer. This reveals that photon energy drives the upgrading of thermal energy in such a hybrid energy system. Rationally designed small-molecule azo switches achieve high gravimetric energy densities of 0.3-0.4 MJ/kg with long-term storage stability. Rechargeable solar thermal battery devices are fabricated, which upon light triggering provide gravimetric power density of about 2.7 kW/kg and temperature increases of >20 °C in ambient environment. We further show their use as deicing coatings. Our work demonstrates a new concept of energy utilization-combining solar energy and low-grade heat into higher-grade heat-which unlocks the possibility of developing sustainable energy systems powered by a combination of natural sunlight and ambient heat.

Introgression of perennial growth habit from Lophopyrum elongatum into wheat.

KEY MESSAGE: A locus for perennial growth was mapped on Lophopyrum elongatum chromosome arm 4ES and introgressed into the wheat genome. Evidence was obtained that in addition to chromosome 4E, other L. elongatum chromosomes control perennial growth. Monocarpy versus polycarpy is one of the fundamental developmental dichotomies in flowering plants. Advances in the understanding of the genetic basis of this dichotomy are important for basic biological reasons and practically for genetic manipulation of growth development in economically important plants. Nine wheat introgression lines (ILs) harboring germplasm of the Lophopyrum elongatum genome present in the octoploid amphiploid Triticum aestivum cv. Chinese Spring (subgenomes AABBDD) × L. elongatum (genomes EE) were selected from a population of ILs developed earlier. These ILs were employed here in genomic analyses of post-sexual cycle regrowth (PSCR), which is a component of polycarpy in caespitose L. elongatum. Analyses of disomic substitution (DS) lines confirmed that L. elongatum chromosome 4E confers PSCR on wheat. The gene was mapped into a short distal region of L. elongatum arm 4ES and was tentatively named Pscr1. ILs harboring recombined chromosomes with 4ES segments, including Pscr1, incorporated into the distal part of the 4DS chromosome arm were identified. Based on the location, Pscr1 is not orthologous with the rice rhizome-development gene Rhz2 located on rice chromosome Os3, which is homoeologous with chromosome 4E, but it may correspond to the Teosinte branched1 (TB1) gene, which is located in the introgressed region in the L. elongatum and Ae. tauschii genomes. A hexaploid IL harboring a large portion of the E-genome but devoid of chromosome 4E also expressed PSCR, which provided evidence that perennial growth is controlled by genes on other L. elongatum chromosomes in addition to 4E.

Genome-wide introgression from a bread wheat × Lophopyrum elongatum amphiploid into wheat.

KEY MESSAGE: We introgressed wheatgrass germplasm from the octoploid amphiploid Triticum aestivum× Lophopyrum elongatum into wheat by manipulating the wheat Ph1 gene and discovered and characterized 130 introgression lines harboring single or, in various combinations, complete and recombined L. elongatum chromosomes. Diploid wheatgrass Lophopyrum elongatum (genomes EE) possesses valuable traits for wheat genetics and breeding. We evaluated several strategies for introgression of this germplasm into wheat. To detect it, we developed and validated multiplexed sets of Sequenom MassARRAY single nucleotide polymorphism (SNP) markers, which differentiated disomic and monosomic L. elongatum chromosomes from wheat chromosomes. We identified 130 introgression lines (ILs), which harbored 108 complete and 89 recombined L. elongatum chromosomes. Of the latter, 59 chromosomes were recombined by one or more crossovers and 30 were involved in centromeric (Robertsonian) translocations or were telocentric. To identify wheat chromosomes substituted for or recombined with L. elongatum chromosomes, we genotyped the ILs with the wheat 90-K Infinium SNP array. We found that most of the wheat 90-K probes correctly detected their targets in the L. elongatum genome and showed that some wheat SNPs are ancient and had originated prior to the divergence of the wheat and L. elongatum lineages. Of the 130 ILs, 52% were homozygous for Ph1 deletion and thus are staged to be recombined further. We failed to detect in the L. elongatum genome the 4/5 reciprocal translocation that has been reported in Thinopyrum bessarabicum and several other Triticeae genomes.

Effects of Sunlight on the Formation Potential of Dichloroacetonitrile and Bromochloroacetonitrile from Wastewater Effluents.

Sunlight plays an important role in transforming effluent organic matter as wastewater effluents travel downstream, but the corresponding effects on the formation of haloacetonitriles (HANs), a group of toxic disinfection byproducts, in wastewater-impacted surface water have not been thoroughly investigated. In this study, we observed that sunlight preferentially attenuated the formation potential of bromochloroacetonitrile (BCAN-FP) over that of dichloroacetonitrile (DCAN-FP) in chlorine- and UV-disinfected secondary effluents. For four effluent samples from different plants, 36 h of irradiation by simulated sunlight removed 28-33% of DCAN-FP and 41-48% of BCAN-FP. Across a larger set of effluent samples (n = 18), 8 h of irradiation (equivalent to 2-3 d of natural sunlight) decreased the calculated cytotoxicity contributed by dihaloacetonitrile-FP in most samples. Similar behavior was observed for a mixture of wastewater and surface water (volume ratio 1:1). For UV-disinfected effluents, the higher the UV dose, the more likely was there a reduction in DCAN-FP and BCAN-FP in the subsequent sunlight irradiation. Experiments with model compounds showed that fulvic acid and UV photoproducts of tryptophan yield excited triplet-state organic matters during sunlight irradiation and play an important role in promoting the attenuation of HAN precursors.

Neurochemical and brain functional changes in the ventromedial prefrontal cortex of first-episode psychosis patients: A combined functional magnetic resonance imaging-proton magnetic resonance spectroscopy study.

OBJECTIVE: Previous studies showed alterations of brain function in the ventromedial prefrontal cortex of schizophrenia patients. Also, neurochemical changes, especially GABA level alteration, have been found in the medial prefrontal cortex of schizophrenia patients. However, the relationship between GABA level in the ventromedial prefrontal cortex and brain functional activity in schizophrenia patients remains unexplored. METHODS: In total, 23 drug-naïve, first-episode psychosis patients and 26 matched healthy controls completed the study. The single voxel proton magnetic resonance spectroscopy data were acquired in ventromedial prefrontal cortex region, which was used as the seed region for resting-state functional connectivity analysis. The proton magnetic resonance spectroscopy data were processed to quantify the concentrations of GABA+, glutamine and glutamate, and N-acetylaspartate in ventromedial prefrontal cortex. Spearman correlation analysis was used to examine the relationship between metabolite concentration, functional connectivity and clinical variables. Pearson correlation analysis was used to examine the relationship between GABA+ concentration and functional connectivity value. RESULTS: In first-episode psychosis patients, GABA+ level in ventromedial prefrontal cortex was higher and was positively correlated with ventromedial prefrontal cortex-left middle orbital frontal cortex functional connectivity. N-acetylaspartate level was positively correlated with positive symptoms, and the functional connectivity between ventromedial prefrontal cortex and left precuneus was negatively associated with negative symptoms of first-episode psychosis patients. CONCLUSION: Our results indicated that ventromedial prefrontal cortex functional connectivity changes were positively correlated with higher local GABA+ level in first-episode psychosis patients. The altered neurochemical concentration and functional connectivity provide insights into the pathology of schizophrenia.

Design of Hierarchical Beads for Efficient Label-Free Cell Capture.

Defined hierarchical materials promise cell analysis and call for application-driven design in practical use. The further issue is to develop advanced materials and devices for efficient label-free cell capture with minimum instrumentation. Herein, the design of hierarchical beads is reported for efficient label-free cell capture. Silica nanoparticles (size of ≈15 nm) are coated onto silica spheres (size of ≈200 nm) to achieve nanoscale surface roughness, and then the rough silica spheres are combined with microbeads (≈150-1000 µm in diameter) to assemble hierarchical structures. These hierarchical beads are built via electrostatic interaction, covalent bonding, and nanoparticle adherence. Further, after functionalization by hyaluronic acid (HA), the hierarchical beads display desirable surface hydrophilicity, biocompatibility, and chemical/structural stability. Due to the controlled surface topology and chemistry, HA-functionalized hierarchical beads afford high cell capture efficiency up to 98.7% in a facile label-free manner. This work guides the development of label-free cell capture techniques and contributes to the construction of smart interfaces in bio-systems.

Effects of Sunlight on the Trichloronitromethane Formation Potential of Wastewater Effluents: Dependence on Nitrite Concentration.

This study examined the effects of sunlight irradiation on the trichloronitromethane formation potential (TCNM-FP) of wastewater effluents and the roles of nitrite and nitrate in this process. Using disinfected secondary effluents from four treatment plants, we observed that sunlight irradiation (320 W/m2) for 8 h attenuated the TCNM-FP by 17-47% for 9 of 14 samples but increased the TCNM-FP for two of the other samples. A longer irradiation time (≤36 h) further reduced the TCNM-FP in a non-nitrified effluent with low nitrite and nitrate concentrations but increased the TCNM-FP in two nitrified effluents by 2-3-fold. When nitrite (0.1-2 mg N/L) was spiked into effluent samples, an increase in the TCNM-FP after irradiation was observed. The higher the nitrite concentration, the greater the increase in the TCNM-FP. In the presence of ∼1 mg N/L of nitrite, sunlight irradiation for 8 h increased the TCNM-FP of four wastewater samples by 0.3-3.6 µg/mg C. In contrast, the spike of nitrate up to 20 mg N/L had no effect. The nitrite-sunlight effect was also observed for four model precursors (humic acid, tryptophan, tyrosine, and phenol). Humic acid and tryptophan featured larger increases in the TCNM-FP compared to those of tyrosine and phenol after sunlight irradiation.

Isotropic Zero Thermal Expansion and Local Vibrational Dynamics in (Sc,Fe)F3.

Scandium fluoride (ScF3) exhibits a pronounced negative thermal expansion (NTE), which can be suppressed and ultimately transformed into an isotropic zero thermal expansion (ZTE) by partially substituting Sc with Fe in (Sc0.8Fe0.2)F3 (Fe20). The latter displays a rather small coefficient of thermal expansion of -0.17 × 10-6/K from 300 to 700 K. Synchrotron X-ray and neutron pair distribution functions confirm that the Sc/Fe-F bond has positive thermal expansion (PTE). Local vibrational dynamics based on extended X-ray absorption fine structure indicates a decreased anisotropy of relative vibration in the Sc/Fe-F bond. Combined analysis proposes a delicate balance between the counteracting effects of the chemical bond PTE and NTE from transverse vibration. The present study extends the scope of isotropic ZTE compounds and, more significantly, provides a complete local vibrational dynamics to shed light on the ZTE mechanism in chemically tailored NTE compounds.

Atomic Linkage Flexibility Tuned Isotropic Negative, Zero, and Positive Thermal Expansion in MZrF6 (M = Ca, Mn, Fe, Co, Ni, and Zn).

The controllable isotropic thermal expansion with a broad coefficient of thermal expansion (CTE) window is intriguing but remains challenge. Herein we report a cubic MZrF6 series (M = Ca, Mn, Fe, Co, Ni and Zn), which exhibit controllable thermal expansion over a wide temperature range and with a broader CTE window (-6.69 to +18.23 × 10-6/K). In particular, an isotropic zero thermal expansion (ZTE) is achieved in ZnZrF6, which is one of the rarely documented high-temperature isotropic ZTE compounds. By utilizing temperature-dependent high-energy synchrotron X-ray total scattering diffraction, it is found that the flexibility of metal···F atomic linkages in MZrF6 plays a critical role in distinct thermal expansions. The flexible metal···F atomic linkages induce negative thermal expansion (NTE) for CaZrF6, whereas the stiff ones bring positive thermal expansion (PTE) for NiZrF6. Thermal expansion could be transformed from striking negative, to zero, and finally to considerable positive though tuning the flexibility of metal···F atomic linkages by substitution with a series of cations on M sites of MZrF6. The present study not only extends the scope of NTE families and rare high-temperature isotropic ZTE compounds but also proposes a new method to design systematically controllable isotropic thermal expansion frameworks from the perspective of atomic linkage flexibility.