Association between serum cytokines and timeframe for conversion from clinical high-risk to psychosis.

AIM: Although many studies have explored the link between inflammatory markers and psychosis, there is a paucity of research investigating the temporal progression in individuals at clinical high-risk (CHR) who eventually develop full psychosis. To address this gap, we investigated the correlation between serum cytokine levels and Timeframe for Conversion to Psychosis (TCP) in individuals with CHR. METHODS: We enrolled 53 individuals with CHR who completed a 5-year follow-up with a confirmed conversion to psychosis. Granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-1ß, 2, 6, 8, 10, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF) levels were measured at baseline and 1-year. Correlation and quantile regression analyses were performed. RESULTS: The median TCP duration was 14 months. A significantly shorter TCP was associated with higher levels of TNF-α (P = 0.022) and VEGF (P = 0.016). A negative correlation was observed between TCP and TNF-α level (P = 0.006) and VEGF level (P = 0.04). Quantile regression indicated negative associations between TCP and GM-CSF levels below the 0.5 quantile, IL-10 levels below the 0.3 quantile, IL-2 levels below the 0.25 quantile, IL-6 levels between the 0.65 and 0.75 quantiles, TNF-α levels below the 0.8 quantile, and VEGF levels below the 0.7 quantile. A mixed linear effects model identified significant time effects for IL-10 and IL-2, and significant group effects for changes in IL-2 and TNF-α. CONCLUSIONS: Our findings underscore that a more pronounced baseline inflammatory state is associated with faster progression of psychosis in individuals with CHR. This highlights the importance of considering individual inflammatory profiles during early intervention and of tailoring preventive measures for risk profiles.

Dual modifying of MAVS at lysine 7 by SIRT3-catalyzed deacetylation and SIRT5-catalyzed desuccinylation orchestrates antiviral innate immunity.

To effectively protect the host from viral infection while avoiding excessive immunopathology, the innate immune response must be tightly controlled. However, the precise regulation of antiviral innate immunity and the underlying mechanisms remain unclear. Here, we find that sirtuin3 (SIRT3) interacts with mitochondrial antiviral signaling protein (MAVS) to catalyze MAVS deacetylation at lysine residue 7 (K7), which promotes MAVS aggregation, as well as TANK-binding kinase I and IRF3 phosphorylation, resulting in increased MAVS activation and enhanced type I interferon signaling. Consistent with these findings, loss of Sirt3 in mice and zebrafish renders them more susceptible to viral infection compared to their wild-type (WT) siblings. However, Sirt3 and Sirt5 double-deficient mice exhibit the same viral susceptibility as their WT littermates, suggesting that loss of Sirt5 in Sirt3-deficient mice may counteract the increased viral susceptibility displayed in Sirt3-deficient mice. Thus, we not only demonstrate that SIRT3 positively regulates antiviral immunity in vitro and in vivo, likely via MAVS, but also uncover a previously unrecognized mechanism by which SIRT3 acts as an accelerator and SIRT5 as a brake to orchestrate antiviral innate immunity.

Childhood maltreatment and personality disorders in adolescents and adults with psychotic or non-psychotic disorders.

Introduction: While the attention to personality disorders (PD) and childhood maltreatment (CM) has grown in recent years, there remains limited understanding of the prevalence and distinctions of PD and CM in clinical populations of Chinese adolescents in comparison to adults. Methods: A total of 1,417 participants were consecutively sampled from patients diagnosed with either psychotic or non-psychotic disorders in the psychiatric and psycho-counseling clinics at Shanghai Mental Health Center. The participants were categorized into two groups based on their age: adolescents (aged 15-21 years) and adults (aged 22-35 years). PDs were evaluated using a self-reported personality diagnostic questionnaire and a structured clinical interview, while CMs were assessed using the Chinese version of the Child Trauma Questionnaire Short Form. Results: When comparing self-reported PD traits and CM between adolescents and adults, differences emerge. Adolescents, particularly in the psychotic disorder group, exhibit more pronounced schizotypal PD traits (p=0.029), and this pattern extends to non-psychotic disorders (p<0.001). Adolescents in the non-psychotic disorder group also report higher levels of emotional abuse (p=0.014), with a notable trend in physical abuse experiences compared to adults (p=0.057). Furthermore, the most prevalent PDs in the clinical sample are avoidant, borderline, and obsessive-compulsive PDs. Among patients with psychotic disorders, adolescents exhibit higher rates of schizoid, schizotypal, and obsessive-compulsive PDs compared to adults. Logistic regression analyses highlight distinct predictors for psychotic and non-psychotic disorders in adolescents and adults. Discussion: The findings emphasize distinct differences in PDs and CMs between adolescent and adult groups, shedding light on their potential roles in psychotic and non-psychotic disorders.

Legume rhizodeposition promotes nitrogen fixation by soil microbiota under crop diversification.

Biological nitrogen fixation by free-living bacteria and rhizobial symbiosis with legumes plays a key role in sustainable crop production. Here, we study how different crop combinations influence the interaction between peanut plants and their rhizosphere microbiota via metabolite deposition and functional responses of free-living and symbiotic nitrogen-fixing bacteria. Based on a long-term (8 year) diversified cropping field experiment, we find that peanut co-cultured with maize and oilseed rape lead to specific changes in peanut rhizosphere metabolite profiles and bacterial functions and nodulation. Flavonoids and coumarins accumulate due to the activation of phenylpropanoid biosynthesis pathways in peanuts. These changes enhance the growth and nitrogen fixation activity of free-living bacterial isolates, and root nodulation by symbiotic Bradyrhizobium isolates. Peanut plant root metabolites interact with Bradyrhizobium isolates contributing to initiate nodulation. Our findings demonstrate that tailored intercropping could be used to improve soil nitrogen availability through changes in the rhizosphere microbiome and its functions.

Threonine dehydrogenase regulates neutrophil homeostasis but not H3K4me3 levels in zebrafish.

l-threonine dehydrogenase (Tdh) is an enzyme that links threonine metabolism to epigenetic modifications and mitochondria biogenesis. In vitro studies show that it is critical for the regulation of trimethylation of histone H3 lysine 4 (H3K4me3) levels and cell fate determination of mouse embryonic stem cells (mESCs). However, whether Tdh regulates a developmental process in vivo and, if it does, whether it also primarily regulates H3K4me3 levels in this process as it does in mESCs, remains elusive. Here, we revealed that, in zebrafish hematopoiesis, tdh is preferentially expressed in neutrophils. Knockout of tdh causes a decrease in neutrophil number and slightly suppresses their acute injury-induced migration, but, unlike the mESCs, the level of H3K4me3 is not evidently reduced in neutrophils sorted from the kidney marrow of adult tdh-null zebrafish. These phenotypes are dependent on the enzymatic activity of Tdh. Importantly, a soluble supplement of nutrients that are able to fuel the acetyl-CoA pool, such as pyruvate, glucose and branched-chain amino acids, is sufficient to rescue the reduction in neutrophils caused by tdh deletion. In summary, our study presents evidence for the functional requirement of Tdh-mediated threonine metabolism in a developmental process in vivo. It also provides an animal model for investigating the nutritional regulation of myelopoiesis and immune response, as well as a useful tool for high-throughput drug/nutrition screening.

Fine-tuning the activation behaviors of ternary modular cabazitaxel prodrugs for efficient and on-target oral anti-cancer therapy.

The disulfide bond plays a crucial role in the design of anti-tumor prodrugs due to its exceptional tumor-specific redox responsiveness. However, premature breaking of disulfide bonds is triggered by small amounts of reducing substances (e.g., ascorbic acid, glutathione, uric acid and tea polyphenols) in the systemic circulation. This may lead to toxicity, particularly in oral prodrugs that require more frequent and high-dose treatments. Fine-tuning the activation kinetics of these prodrugs is a promising prospect for more efficient on-target cancer therapies. In this study, disulfide, steric disulfide, and ester bonds were used to bridge cabazitaxel (CTX) to an intestinal lymph vessel-directed triglyceride (TG) module. Then, synthetic prodrugs were efficiently incorporated into self-nanoemulsifying drug delivery system (corn oil and Maisine CC were used as the oil phase and Cremophor EL as the surfactant). All three prodrugs had excellent gastric stability and intestinal permeability. The oral bioavailability of the disulfide bond-based prodrugs (CTX-(C)S-(C)S-TG and CTX-S-S-TG) was 11.5- and 19.1-fold higher than that of the CTX solution, respectively, demonstrating good oral delivery efficiency. However, the excessive reduction sensitivity of the disulfide bond resulted in lower plasma stability and safety of CTX-S-S-TG than that of CTX-(C)S-(C)S-TG. Moreover, introducing steric hindrance into disulfide bonds could also modulate drug release and cytotoxicity, significantly improving the anti-tumor activity even compared to that of intravenous CTX solution at half dosage while minimizing off-target adverse effects. Our findings provide insights into the design and fine-tuning of different disulfide bond-based linkers, which may help identify oral prodrugs with more potent therapeutic efficacy and safety for cancer therapy.

IncX3 plasmid-mediated spread of blaNDM gene in Enterobacteriaceae among children in China.

BACKGROUND: blaNDM gene was prevalent among children, and became the predominant cause of severe infection in infants and children. This study aimed to investigate the epidemiology and molecular characteristics of blaNDM in Enterobacteriaceae among children in China. METHODS: Carbapenem-resistant Enterobacteriaceae (CRE) were collected in the Children's Hospital of Fudan University from January 2016 to December 2022. Five carbapenemase genes (blaKPC, blaNDM, blaVIM, blaIMP, blaOXA-48) were screened by PCR method. Multilocus sequence typing (MLST) was conducted for phylogenetic analyses. blaNDM-carrying plasmids were typed by PCR-based Incompatibility (Inc) typing method. Moreover, plasmid comparison was performed with 213 publicly available IncX3 plasmids. RESULTS: A total of 330 CRE strains were enrolled, 96.4% of which carried carbapenemase genes. blaNDM gene accounted for 64.8% (214 strains) and included four variants, including blaNDM-1 (59.8%), blaNDM-5 (39.3%), blaNDM-7 (0.5%) and blaNDM-9 (0.5%). There were no predominant MLST lineages of blaNDM carrying strains. IncX3 was the major plasmid carrying blaNDM-1 (68.0%) and blaNDM-5 (72.6%), and was dominant in blaNDM-K. penumoniae (79.8%), blaNDM-E. coli (58.2%) and blaNDM-E. cloacae (61.0%), respectively. Majority (79.0%) of clinical IncX3 plasmids in the world carried blaNDM, and the prevalence of blaNDM in IncX3 plasmids was more common in China (95.8%) than other countries (58.1%, p<0.01). CONCLUSION: blaNDM is highly prevalent in CREs among children in China. The spread of blaNDM was mainly mediated by IncX3 plasmids. Surveillance and infection control on the spread of blaNDM among children are important.

A patient-specific lung cancer assembloid model with heterogeneous tumor microenvironments.

Cancer models play critical roles in basic cancer research and precision medicine. However, current in vitro cancer models are limited by their inability to mimic the three-dimensional architecture and heterogeneous tumor microenvironments (TME) of in vivo tumors. Here, we develop an innovative patient-specific lung cancer assembloid (LCA) model by using droplet microfluidic technology based on a microinjection strategy. This method enables precise manipulation of clinical microsamples and rapid generation of LCAs with good intra-batch consistency in size and cell composition by evenly encapsulating patient tumor-derived TME cells and lung cancer organoids inside microgels. LCAs recapitulate the inter- and intratumoral heterogeneity, TME cellular diversity, and genomic and transcriptomic landscape of their parental tumors. LCA model could reconstruct the functional heterogeneity of cancer-associated fibroblasts and reflect the influence of TME on drug responses compared to cancer organoids. Notably, LCAs accurately replicate the clinical outcomes of patients, suggesting the potential of the LCA model to predict personalized treatments. Collectively, our studies provide a valuable method for precisely fabricating cancer assembloids and a promising LCA model for cancer research and personalized medicine.

Repetitive transcranial magnetic stimulation can improve negative symptoms and/or neurocognitive impairments in the first psychosis episode: A randomized controlled trial.

OBJECTIVE: Negative symptoms and neurocognitive impairments in psychosis correlate with their severity. Currently, there is no satisfactory treatment. We aimed to evaluate and compare the effects of repetitive transcranial magnetic stimulation(rTMS) on negative symptoms and neurocognitive impairments in patients in first-episode of psychosis(FEP) in a randomized controlled trial(RCT). METHOD: This is a single-site RCT of 85 patients with FEP. Patients were randomized to receive a 4-week course of active(n = 45) or sham rTMS(n = 40). Factor analysis was applied to a cross-sectional dataset of 744 FEP patients who completed negative symptom evaluation and neurocognitive battery tests. Two independent dimensions were generated and used for the K-means cluster analysis to produce sub-clusters. rTMS of 1-Hz was delivered to the right orbitofrontal(OFC) cortex. RESULTS: Two distinct dimensional factors of neurocognitive functions(factor-1) and negative symptoms(factor-2), and three clusters with distinctive features were generated. Significant improvements in factor-1 and factor-2 were observed after 4-weeks of rTMS treatment in both the active and sham rTMS groups. The repeated-measures analysis of variance revealed a significant effect of time×group(F = 5.594, p = 0.021, η2 = 0.073) on factor-2, but no effect of time×group on factor-1. Only improvements in negative symptoms were significantly different between the active and sham rTMS groups(p = 0.028). Patients in cluster-3 characterized by extensive negative symptoms, showed greater improvement in the active rTMS group than in the sham rTMS group. CONCLUSIONS: The 1-Hz right OFC cortex rTMS is more effective in reducing negative symptoms than neurocognitive impairments. It is especially effective in patients with dominantly negative symptoms in FEP.

Research strategies of small molecules as chemotherapeutics to overcome multiple myeloma resistance.

Multiple myeloma (MM), a cancer of plasma cells, is the second most common hematological malignancy which is characterized by aberrant plasma cells infiltration in the bone marrow and complex heterogeneous cytogenetic abnormalities. Over the past two decades, novel treatment strategies such as proteasome inhibitors, immunomodulators, and monoclonal antibodies have significantly improved the relative survival rate of MM patients. However, the development of drug resistance results in the majority of MM patients suffering from relapse, limited treatment options and uncontrolled disease progression after relapse. There are urgent needs to develop and explore novel MM treatment strategies to overcome drug resistance and improve efficacy. Here, we review the recent small molecule therapeutic strategies for MM, and introduce potential new targets and corresponding modulators in detail. In addition, this paper also summarizes the progress of multi-target inhibitor therapy and protein degradation technology in the treatment of MM.

Corrigendum: The central inflammatory regulator IκBζ: induction regulation and physiological functions.

[This corrects the article DOI: 10.3389/fimmu.2023.1188253.].

Epidemiological investigation of Cryptosporidium in children with diarrhea in middle Inner Mongolia, China.

Cryptosporidia (Cryptosporidium) is a protozoan that is widely parasitic in the intestinal cells of humans and animals, and it is also an important zoonotic parasite. However, there is no epidemiological investigation on Cryptosporidium spp. infection in infants with diarrhea of Inner Mongolia, the largest livestock region in China. To investigate the prevalence of Cryptosporidium, 2435 fresh fecal samples were collected from children with diarrhea in Inner Mongolia Maternal and Child Health Care Hospital. Molecular characterization of Cryptosporidium was carried out based on its 18S rRNA and gp60 gene sequences. The overall prevalence was 12.85% (313/2435), and in Hohhot (12.15%), it was lower than that in the surrounding city (14.87%) (P < 0.05). Moreover, Cryptosporidium was detected in different seasons and sexes. Concerning the age of children with diarrhea, the prevalence of those age groups between 0 and 1 was obviously lower than others, and there were significant differences in the prevalence at different ages (P < 0.001). Analysis of the 18S rRNA gene sequence revealed that all the positive samples were Cryptosporidium parvum, and there were 5 subtypes (IIdA23G3, IIdA24G3, IIdA24G4, IIdA25G3, and IIdA25G4). To the best of our knowledge, the above subtypes have not been reported. Our results provide a relevant basis for control and education on food safety and foodborne illness prevention.

TGF-ß1-triggered BMI1 and SMAD2 cooperatively regulate miR-191 to modulate bone formation.

Transforming growth factor ß 1 (TGF-ß1), as the most abundant signaling molecule in bone matrix, is essential for bone homeostasis. However, the signaling transduction of TGF-ß1 in the bone-forming microenvironment remains unknown. Here, we showed that microRNA-191 (miR-191) was downregulated during osteogenesis and further decreased by osteo-favoring TGF-ß1 in bone marrow mesenchymal stem cells (BMSCs). MiR-191 was lower in bone tissues from children than in those from middle-aged individuals and it was negatively correlated with collagen type I alpha 1 chain (COL1A1). MiR-191 depletion significantly increased osteogenesis and bone formation in vivo. Hydrogels embedded with miR-191-low BMSCs displayed a powerful bone repair effect. Mechanistically, transcription factors BMI1 and SMAD2 coordinately controlled miR-191 level. In detail, BMI1 and pSMAD2 were both upregulated by TGF-ß1 under osteogenic condition. SMAD2 activated miR-191 transcription, while BMI1 competed with SMAD2 for binding to miR-191 promoter region, thus disturbing the activation of SMAD2 on miR-191 and reducing miR-191 level. Altogether, our findings reveal that miR-191 regulated by TGF-ß1-induced BMI1 and SMAD2 negatively modulated bone formation and regeneration, and inhibition of miR-191 might be therapeutically useful to enhance bone repair in clinic.

Catalytic Ring Expanding Difluorination: An Enantioselective Platform to Access ß,ß-Difluorinated Carbocycles.

Cyclic ß,ß-difluoro-carbonyl compounds have a venerable history as drug discovery leads, but limitations in the synthesis arsenal continue to impede chemical space exploration. This challenge is particularly acute in the arena of fluorinated medium rings where installing the difluoromethylene unit subtly alters the ring conformation by expanding the internal angle (∠C-CF2-C>∠C-CH2-C): this provides a handle to modulate physicochemistry (e.g. pKa). To reconcile this disparity, a highly modular ring expansion has been devised that leverages simple α,ß-unsaturated esters and amides, and processes them to one-carbon homologated rings with concomitant geminal difluorination (6 to 10 membered rings, up to 95 % yield). This process is a rare example of the formal difluorination of an internal alkene and is enabled by sequential I(III)-enabled O-activation. Validation of enantioselective catalysis in the generation of unprecedented medium ring scaffolds is reported (up to 93 : 7 e.r.) together with X-ray structural analyses and product derivatization.

Overcoming Endosomal Escape Barriers in Gene Drug Delivery Using De Novo Designed pH-Responsive Peptides.

A major challenge in using nanocarriers for intracellular drug delivery is their restricted capacity to escape from endosomes into the cytosol. Here, we significantly enhance the drug delivery efficiency by accurately predicting and regulating the transition pH (pH0) of peptides to modulate their endosomal escape capability. Moreover, by inverting the chirality of the peptide carriers, we could further enhance their ability to deliver nucleic acid drugs as well as antitumor drugs. The resulting peptide carriers exhibit versatility in transfecting various cell types with a high efficiency of up to 90% by using siRNA, pDNA, and mRNA. In vivo antitumor experiments demonstrate a tumor growth inhibition of 83.4% using the peptide. This research offers a potent method for the rapid development of peptide vectors with exceptional transfection efficiencies for diverse pathophysiological indications.

Models of mild cognitive deficits in risk assessment in early psychosis.

BACKGROUND: Mild cognitive deficits (MCD) emerge before the first episode of psychosis (FEP) and persist in the clinical high-risk (CHR) stage. This study aims to refine risk prediction by developing MCD models optimized for specific early psychosis stages and target populations. METHODS: A comprehensive neuropsychological battery assessed 1059 individuals with FEP, 794 CHR, and 774 matched healthy controls (HCs). CHR subjects, followed up for 2 years, were categorized into converters (CHR-C) and non-converters (CHR-NC). The MATRICS Consensus Cognitive Battery standardized neurocognitive tests were employed. RESULTS: Both the CHR and FEP groups exhibited significantly poorer performance compared to the HC group across all neurocognitive tests (all p < 0.001). The CHR-C group demonstrated poorer performance compared to the CHR-NC group on three sub-tests: visuospatial memory (p < 0.001), mazes (p = 0.005), and symbol coding (p = 0.023) tests. Upon adjusting for sex and age, the performance of the MCD model was excellent in differentiating FEP from HC, as evidenced by an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.895 (p < 0.001). However, when applied in the CHR group for predicting CHR-C (AUC = 0.581, p = 0.008), the performance was not satisfactory. To optimize the efficiency of psychotic risk assessment, three distinct MCD models were developed to distinguish FEP from HC, predict CHR-C from CHR-NC, and identify CHR from HC, achieving accuracies of 89.3%, 65.6%, and 80.2%, respectively. CONCLUSIONS: The MCD exhibits variations in domains, patterns, and weights across different stages of early psychosis and diverse target populations. Emphasizing precise risk assessment, our findings highlight the importance of tailored MCD models for different stages and risk levels.

Association between prenatal antipsychotic exposure and the risk of attention-deficit/hyperactivity disorder and autism spectrum disorder: a systematic review and meta-analysis.

The paucity of evidence regarding the safety of gestational antipsychotic exposure has led to treatment discontinuation in pregnant women with severe mental health conditions. This systematic review and meta-analysis aimed to summarise the current evidence on the association between gestational antipsychotic exposure and attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in children (Study protocol registered in PROSPERO:CRD42022311354). Five studies included in our meta-analysis with around 8.6 million pregnancy episodes in nine different countries/regions. Results from our meta-analysis indicate that the heightened risks of ASD and ADHD in children gestationally exposed to antipsychotics appear to be attributable to maternal characteristics, rather than having a causal relationship with the antipsychotic exposure during pregnancy. The results underscore the importance of meticulously monitoring the neurodevelopment of children born to mothers with mental illnesses, which can facilitate early interventions and provide requisite support.

Pharmacological approaches for targeting lysosomes to induce ferroptotic cell death in cancer.

Lysosomes are crucial organelles responsible for the degradation of cytosolic materials and bulky organelles, thereby facilitating nutrient recycling and cell survival. However, lysosome also acts as an executioner of cell death, including ferroptosis, a distinctive form of regulated cell death that hinges on iron-dependent phospholipid peroxidation. The initiation of ferroptosis necessitates three key components: substrates (membrane phospholipids enriched with polyunsaturated fatty acids), triggers (redox-active irons), and compromised defence mechanisms (GPX4-dependent and -independent antioxidant systems). Notably, iron assumes a pivotal role in ferroptotic cell death, particularly in the context of cancer, where iron and oncogenic signaling pathways reciprocally reinforce each other. Given the lysosomes' central role in iron metabolism, various strategies have been devised to harness lysosome-mediated iron metabolism to induce ferroptosis. These include the re-mobilization of iron from intracellular storage sites such as ferritin complex and mitochondria through ferritinophagy and mitophagy, respectively. Additionally, transcriptional regulation of lysosomal and autophagy genes by TFEB enhances lysosomal function. Moreover, the induction of lysosomal iron overload can lead to lysosomal membrane permeabilization and subsequent cell death. Extensive screening and individually studies have explored pharmacological interventions using clinically available drugs and phytochemical agents. Furthermore, a drug delivery system involving ferritin-coated nanoparticles has been specifically tailored to target cancer cells overexpressing TFRC. With the rapid advancements in understandings the mechanistic underpinnings of ferroptosis and iron metabolism, it is increasingly evident that lysosomes represent a promising target for inducing ferroptosis and combating cancer.

Discovery of RORγ Allosteric Fluorescent Probes and Their Application: Fluorescence Polarization, Screening, and Bioimaging.

Retinoic acid receptor-related orphan receptor γ (RORγ) acts as a crucial transcription factor in Th17 cells and is involved in diverse autoimmune disorders. RORγ allosteric inhibitors have gained significant research focus as a novel strategy to inhibit RORγ transcriptional activity. Leveraging the high affinity and selectivity of RORγ allosteric inhibitor MRL-871 (1), this study presents the design, synthesis, and characterization of 11 allosteric fluorescent probes. Utilizing the preferred probe 12h, we established an efficient and cost-effective fluorescence polarization-based affinity assay for screening RORγ allosteric binders. By employing virtual screening in conjunction with this assay, 10 novel RORγ allosteric inhibitors were identified. The initial SAR studies focusing on the hit compound G381-0087 are also presented. The encouraging outcomes indicate that probe 12h possesses the potential to function as a powerful tool in facilitating the exploration of RORγ allosteric inhibitors and furthering understanding of RORγ function.