108 research outputs found
Reversible DielsâAlder Reactions with a Fluorescent Dye on the Surface of Magnetite Nanoparticles
DielsâAlder reactions on the surface of nanoparticles allow a thermoreversible functionalization of the nanosized building blocks. We report the synthesis of well-defined magnetite
nanoparticles by thermal decomposition reaction and their functionalization with maleimide groups.
Attachment of these dienophiles was realized by the synthesis of organophosphonate coupling agents
and a partial ligand exchange of the original carboxylic acid groups. The functionalized iron oxide
particles allow a covalent surface attachment of a furfuryl-functionalized rhodamine B dye by a
DielsâAlder reaction at 60 âŠC. The resulting particles showed the typical fluorescence of rhodamine
B. The dye can be cleaved off the particle surface by a retro-DielsâAlder reaction. The study showed
that organic functions can be thermoreversibly attached onto inorganic nanoparticles
FELM: Benchmarking Factuality Evaluation of Large Language Models
Assessing factuality of text generated by large language models (LLMs) is an
emerging yet crucial research area, aimed at alerting users to potential errors
and guiding the development of more reliable LLMs. Nonetheless, the evaluators
assessing factuality necessitate suitable evaluation themselves to gauge
progress and foster advancements. This direction remains under-explored,
resulting in substantial impediments to the progress of factuality evaluators.
To mitigate this issue, we introduce a benchmark for Factuality Evaluation of
large Language Models, referred to as felm. In this benchmark, we collect
responses generated from LLMs and annotate factuality labels in a fine-grained
manner. Contrary to previous studies that primarily concentrate on the
factuality of world knowledge (e.g.~information from Wikipedia), felm focuses
on factuality across diverse domains, spanning from world knowledge to math and
reasoning. Our annotation is based on text segments, which can help pinpoint
specific factual errors. The factuality annotations are further supplemented by
predefined error types and reference links that either support or contradict
the statement. In our experiments, we investigate the performance of several
LLM-based factuality evaluators on felm, including both vanilla LLMs and those
augmented with retrieval mechanisms and chain-of-thought processes. Our
findings reveal that while retrieval aids factuality evaluation, current LLMs
are far from satisfactory to faithfully detect factual errors.Comment: Accepted by NeurIPS 2023 Track on Datasets and Benchmark
Causal relationship between human blood metabolites and risk of ischemic stroke: a Mendelian randomization study
Background: Ischemic stroke (IS) is a major cause of death and disability worldwide. Previous studies have reported associations between metabolic disorders and IS. However, evidence regarding the causal relationship between blood metabolites and IS lacking.Methods: A two-sample Mendelian randomization analysis (MR) was used to assess the causal relationship between 1,400 serum metabolites and IS. The inverse variance-weighted (IVW) method was employed to estimate the causal effect between exposure and outcome. Additionally, MR-Egger regression, weighted median, simple mode, and weighted mode approaches were employed as supplementary comprehensive evaluations of the causal effects between blood metabolites and IS. Tests for pleiotropy and heterogeneity were conducted.Results: After rigorous selection, 23 known and 5 unknown metabolites were identified to be associated with IS. Among the 23 known metabolites, 13 showed significant causal effects with IS based on 2 MR methods, including 5-acetylamino-6-formylamino-3-methyluracil, 1-ribosyl-imidazoleacetate, Behenoylcarnitine (C22), N-acetyltyrosine, and N-acetylputrescine to (N (1) + N (8))-acetate,these five metabolites were positively associated with increased IS risk. Xanthurenate, Glycosyl-N-tricosanoyl-sphingadienine, Orotate, Bilirubin (E,E), Bilirubin degradation product, C17H18N2O, Bilirubin (Z,Z) to androsterone glucuronide, Bilirubin (Z,Z) to etiocholanolone glucuronide, Biliverdin, and Uridine to pseudouridine ratio were associated with decreased IS risk.Conclusion: Among 1,400 blood metabolites, this study identified 23 known metabolites that are significantly associated with IS risk, with 13 being more prominent. The integration of genomics and metabolomics provides important insights for the screening and prevention of IS
Effects of nitrogen fertilization and bioenergy crop type on topsoil organic carbon and total Nitrogen contents in middle Tennessee USA
Nitrogen (N) fertilization affects bioenergy crop growth and productivity and consequently carbon (C) and N contents in soil, it however remains unclear whether N fertilization and crop type individually or interactively influence soil organic carbon (SOC) and total N (TN). In a three-year long fertilization experiment in switchgrass (SG: Panicum virgatum L.) and gamagrass (GG: Tripsacum dactyloides L.) croplands in Middle Tennessee USA, soil samples (0â15cm) were collected in plots with no N input (NN), low N input (LN: 84 kg N ha-1 yr-1 in urea) and high N input (HN: 168 kg N ha-1 yr-1 in urea). Besides SOC and TN, the aboveground plant biomass was also quantified. In addition to a summary of published root morphology data based on a separated mesocosm experiment, the root leachable dissolved organic matter (DOM) of both crops was also measured using archived samples. Results showed no significant interaction of N fertilization and crop type on SOC, TN or plant aboveground biomass (ABG). Relative to NN, HN (not LN) significantly increased SOC and TN in both crops. Though SG showed a 15â68% significantly higher ABG than GG, GG showed a 9.3â12% significantly higher SOC and TN than SG. The positive linear relationships of SOC or TN with ABG were identified for SG. However, GG showed structurally more complex and less readily decomposed root DOM, a larger root volume, total root length and surface area than SG. Collectively, these suggested that intensive N fertilization could increase C and N stocks in bioenergy cropland soils but these effects may be more likely mediated by the aboveground biomass in SG and root chemistry and morphology in GG. Future studies are expected to examine the root characteristics in different bioenergy croplands under the field fertilization experiment
Selection of Anti-Sulfadimidine Specific ScFvs from a Hybridoma Cell by Eukaryotic Ribosome Display
BACKGROUND:Ribosome display technology has provided an alternative platform technology for the development of novel low-cost antibody based on evaluating antibiotics derived residues in food matrixes. METHODOLOGY/PRINCIPAL FINDINGS:In our current studies, the single chain variable fragments (scFvs) were selected from hybridoma cell lines against sulfadimidine (SM(2)) by using a ribosome library technology. A DNA library of scFv antibody fragments was constructed for ribosome display, and then mRNA-ribosome-antibody (MRA) complexes were produced by a rabbit reticulocyte lysate system. The synthetic sulfadimidine-ovalbumin (SM(2)-OVA) was used as an antigen to pan MRA complexes and putative scFv-encoding genes were recovered by RT-PCR in situ following each panning. After four rounds of ribosome display, the expression vector pCANTAB5E containing the selected specific scFv DNA was constructed and transformed into Escherichia coli HB2151. Three positive clones (SAS14, SAS68 and SAS71) were screened from 100 clones and had higher antibody activity and specificity to SM(2) by indirect ELISA. The three specific soluble scFvs were identified to be the same molecular weight (approximately 30 kDa) by Western-blotting analysis using anti-E tag antibodies, but they had different amino acids sequence by sequence analysis. CONCLUSIONS/SIGNIFICANCE:The selection of anti-SM(2) specific scFv by in vitro ribosome display technology will have an important significance for the development of novel immunodetection strategies for residual veterinary drugs
Expert consensus on spontaneous ventilation video-assisted thoracoscopic surgery in primary spontaneous pneumothorax (Guangzhou)
Characterization of two HIV-1 infectors during initial antiretroviral treatment, and the emergence of phenotypic resistance in reverse transcriptase-associated mutation patterns
Aggregation-Induced Emission (AIE), Life and Health
Light has profoundly impacted modern medicine and healthcare, with numerous luminescent agents and imaging techniques currently being used to assess health and treat diseases. As an emerging concept in luminescence, aggregation-induced emission (AIE) has shown great potential in biological applications due to its advantages in terms of brightness, biocompatibility, photostability, and positive correlation with concentration. This review provides a comprehensive summary of AIE luminogens applied in imaging of biological structure and dynamic physiological processes, disease diagnosis and treatment, and detection and monitoring of specific analytes, followed by representative works. Discussions on critical issues and perspectives on future directions are also included. This review aims to stimulate the interest of researchers from different fields, including chemistry, biology, materials science, medicine, etc., thus promoting the development of AIE in the fields of life and health
Reversible DielsâAlder Reactions with a Fluorescent Dye on the Surface of Magnetite Nanoparticles
DielsâAlder reactions on the surface of nanoparticles allow a thermoreversible functionalization of the nanosized building blocks. We report the synthesis of well-defined magnetite nanoparticles by thermal decomposition reaction and their functionalization with maleimide groups. Attachment of these dienophiles was realized by the synthesis of organophosphonate coupling agents and a partial ligand exchange of the original carboxylic acid groups. The functionalized iron oxide particles allow a covalent surface attachment of a furfuryl-functionalized rhodamine B dye by a DielsâAlder reaction at 60 °C. The resulting particles showed the typical fluorescence of rhodamine B. The dye can be cleaved off the particle surface by a retro-DielsâAlder reaction. The study showed that organic functions can be thermoreversibly attached onto inorganic nanoparticles
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