Co-Catalyzed Hydrofluorination of Alkenes: Photocatalytic Method Development and Electroanalytical Mechanistic Investigation.

The hydrofluorination of alkenes represents an attractive strategy for the synthesis of aliphatic fluorides. This approach provides a direct means to form C(sp3)-F bonds selectively from readily available alkenes. Nonetheless, conducting hydrofluorination using nucleophilic fluorine sources poses significant challenges due to the low acidity and high toxicity associated with HF and the poor nucleophilicity of fluoride. In this study, we present a new Co(salen)-catalyzed hydrofluorination of simple alkenes utilizing Et3N·3HF as the sole source of both hydrogen and fluorine. This process operates via a photoredox-mediated polar-radical-polar crossover mechanism. We also demonstrated the versatility of this method by effectively converting a diverse array of simple and activated alkenes with varying degrees of substitution into hydrofluorinated products. Furthermore, we successfully applied this methodology to 18F-hydrofluorination reactions, enabling the introduction of 18F into potential radiopharmaceuticals. Our mechanistic investigations, conducted using rotating disk electrode voltammetry and DFT calculations, unveiled the involvement of both carbocation and CoIV-alkyl species as viable intermediates during the fluorination step, and the contribution of each pathway depends on the structure of the starting alkene.

Macrophage-Membrane-Camouflaged Nonviral Gene Vectors for the Treatment of Multidrug-Resistant Bacterial Sepsis.

Sepsis is a life-threatening disease caused by systemic bacterial infections, with high morbidity and mortality worldwide. As the standard treatment for sepsis, antibiotic therapy faces the challenge of impaired macrophages and drug-resistant bacteria. In this study, we developed a membrane-camouflaged metal-organic framework (MOF) system for plasmid DNA (pDNA) delivery to combat sepsis. The antimicrobial gene LL37 was efficiently encapsulated in the pH-sensitive MOF, and the nanoparticles were decorated with macrophage membranes in a compatible manner. Macrophage membrane coating allows targeted delivery of LL37 to macrophages and creates macrophage factories for the continuous generation of antimicrobial peptides. Compared to naked nanoparticles, primary bone marrow mesenchymal macrophage membrane-modified nanoparticles greatly improved the survival rate of immunodeficient septic mice through the synergistic effect of efficient gene therapy and inflammatory cytokine sequestration. This study demonstrates an effective membrane biomimetic strategy for efficiently delivering pDNA, offering an excellent option for overcoming sepsis.

Intercepting Hydrogen Evolution with Hydrogen-Atom Transfer: Electron-Initiated Hydrofunctionalization of Alkenes.

Hydrogen-atom transfer mediated by earth-abundant transition-metal hydrides (M-Hs) has emerged as a powerful tool in organic synthesis. Current methods to generate M-Hs most frequently rely on oxidatively initiated hydride transfer. Herein, we report a reductive approach to generate Co-H, which allows for canonical hydrogen evolution reactions to be intercepted by hydrogen-atom transfer to an alkene. Electroanalytical and spectroscopic studies provided mechanistic insights into the formation and reactivity of Co-H, which enabled the development of two new alkene hydrofunctionalization reactions.

Paclitaxel-based supramolecular hydrogel loaded with mifepristone for the inhibition of breast cancer metastasis.

Breast cancer is the leading cause of cancer death among women and almost all of the breast cancer-caused mortality is related to metastasis. It has been reported that glucocorticoid facilitates the metastasis of breast cancer in mice, and mifepristone can antagonize the effect of glucocorticoid. Paclitaxel is one of the important drugs in the treatment of breast cancer. Mifepristone combined with paclitaxel could be an effective strategy for inhibiting breast cancer metastasis. However, their inherent defects, in terms of short blood circulation half-life and lack of tumor targeting, not only limit their effectiveness but also cause adverse reactions. Therefore, our aim is to explore a novel protocol against breast cancer metastasis, further optimize its therapeutic efficacy by a nanodelivery system, and explore its mechanism. Herein, a paclitaxel-conjugated and mifepristone-loaded hydrogel (PM-nano) was prepared by self-assembly. Its characterizations were studied. The antimetastatic effect was evaluated in vitro and in vivo and its mechanism was also explored by western blot assay. The resultant PM-nano was developed with favorable water solubility and good biocompatibility. Moreover, PM-nano displayed increased cell uptake properties and stimulated drug release in the tumor micro-acidic environment. The PM-nano was more effective in inhibiting the proliferation and metastasis of breast cancer than other groups in vitro and in vivo. The PM-nano might inhibit metastasis through glucocorticoid receptor/receptor tyrosine kinase-like orphan receptor 1 and MMPs. Taken together, PM-nano showed superior antimetastatic effects against breast cancer and excellent biocompatibility in vitro and in vivo, providing a new option for limiting metastasis.

Electrocatalysis as an enabling technology for organic synthesis.

Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. Electrochemistry's unique ability to generate highly reactive radical and radical ion intermediates in a controlled fashion under mild conditions has inspired the development of a number of new electrochemical methodologies for the preparation of valuable chemical motifs. Particularly, recent developments in electrosynthesis have featured an increased use of redox-active electrocatalysts to further enhance control over the selective formation and downstream reactivity of these reactive intermediates. Furthermore, electrocatalytic mediators enable synthetic transformations to proceed in a manner that is mechanistically distinct from purely chemical methods, allowing for the subversion of kinetic and thermodynamic obstacles encountered in conventional organic synthesis. This review highlights key innovations within the past decade in the area of synthetic electrocatalysis, with emphasis on the mechanisms and catalyst design principles underpinning these advancements. A host of oxidative and reductive electrocatalytic methodologies are discussed and are grouped according to the classification of the synthetic transformation and the nature of the electrocatalyst.

Enhanced radiotherapy using photothermal therapy based on dual-sensitizer of gold nanoparticles with acid-induced aggregation.

The damaged DNA strands caused by radiotherapy (RT) can repair by themselves. A gold nanoparticles (GNPs) system with acid-induced aggregation was developed into a dual sensitizer owing to its high radioactive rays attenuation ability and enhanced photothermal heating efficiency after GNPs aggregation to achieve a combination therapy of RT and photothermal therapy (PTT). In this combination therapy, the formed GNP aggregates firstly showed a higher sensitize enhancement ratio (SER) value (1.52). Importantly, the self-repair of damaged DNA strands was inhibited by mild PTT through down-regulating the expression of DNA repair protein, thus resulting in a much higher SER value (1.68). Anti-tumor studies further demonstrated that this combination therapy exhibited ideal anti-tumor efficacy. Furthermore, the imaging signals of GNPs in computed tomography and photoacoustic were significantly improved following the GNPs aggregation. Therefore, a dual sensitizer with multimodal imaging was successfully developed and can be further applied as a new anti-tumor therapy.

New Bisoxazoline Ligands Enable Enantioselective Electrocatalytic Cyanofunctionalization of Vinylarenes.

In contrast to the rapid growth of synthetic electrochemistry in recent years, enantioselective catalytic methods powered by electricity remain rare. In this work, we report the development of a highly enantioselective method for the electrochemical cyanophosphinoylation of vinylarenes. A new family of serine-derived chiral bisoxazolines with ancillary coordination sites were identified as optimal ligands.

Photoswitchable Micelles for the Control of Singlet-Oxygen Generation in Photodynamic Therapies.

Inadvertent photosensitizer-activation and singlet-oxygen generation hampers clinical application of photodynamic therapies of superficial tumors or subcutaneous infections. Therefore, a reversible photoswitchable system was designed in micellar nanocarriers using ZnTPP as a photosensitizer and BDTE as a photoswitch. Singlet-oxygen generation upon irradiation didnot occur in closed-switch micelles with ZnTPP/BDTE feeding ratios >1:10. Deliberate switch closure/opening within 65-80 min was possible through thin layers of porcine tissue in vitro, increasing for thicker layers. Inadvertent opening of the switch by simulated daylight, took several tens of hours. Creating deliberate cell damage and prevention of inadvertent damage in vitro and in mice could be done at lower ZnTPP/BDTE feeding ratios (1:5) in open-switch micelles and at higher irradiation intensities than inferred from chemical clues to generate singlet-oxygen. The reduction of inadvertent photosensitizer activation in micellar nanocarriers, while maintaining the ability to kill tumor cells and infectious bacteria established here, brings photodynamic therapies closer to clinical application.

Dual Fluorescent- and Isotopic-Labelled Self-Assembling Vancomycin for in†vivo Imaging of Bacterial Infections.

The increase of bacterial resistance demands rapid and accurate diagnosis of bacterial infections. Biosurface-induced supramolecular assembly for diagnosis and therapy has received little attention in detecting bacterial infections. Herein we present a dual fluorescent-nuclear probe based on self-assembly of vancomycin (Van) on Gram-positive bacteria for imaging bacterial infection. A Van- and rhodamine-modified peptide derivative (Rho-FF-Van), as the imaging agent, binds to the terminal peptide of the methicillin-resistant staphylococcus aureus (MRSA) and self-assembles to form nanoaggregates on the surface of MRSA. In an in vivo myositis model, Rho-FF-Van results in a significant increased fluorescence signal at the MRSA infected site. Radiolabeled with iodine-125, Rho-FF-Van shows strong radioactive signal in the MRSA-infected lungs in a murine model. This novel dual fluorescent and nuclear probe promises a new way for in vivo imaging of bacterial infections.

A Fusion Protein of RGD4C and ß-Lactamase Has a Favorable Targeting Effect in Its Use in Antibody Directed Enzyme Prodrug Therapy.

Antibody directed enzyme prodrug therapy (ADEPT) utilizing ß-lactamase is a promising treatment strategy to enhance the therapeutic effect and safety of cytotoxic agents. In this method, a conjugate (antibody-ß-lactamase fusion protein) is employed to precisely activate nontoxic cephalosporin prodrugs at the tumor site. A major obstacle to the clinical translation of this method, however, is the low catalytic activity and high immunogenicity of the wild-type enzymes. To overcome this challenge, we fused a cyclic decapeptide (RGD4C) targeting to the integrin with a ß-lactamase variant with reduced immunogenicity which retains acceptable catalytic activity for prodrug hydrolysis. Here, we made a further investigation on its targeting effect and pharmacokinetic properties, the results demonstrated that the fusion protein retains a targeting effect on integrin positive cells and has acceptable pharmacokinetic characteristics, which benefits its use in ADEPT.

PEG-b-PCL copolymer micelles with the ability of pH-controlled negative-to-positive charge reversal for intracellular delivery of doxorubicin.

The application of PEG-b-PCL micelles was dampened by their inherent low drug-loading capability and relatively poor cell uptake efficiency. In this study, a series of novel PEG-b-PCL copolymers methoxy poly(ethylene glycol)-b-poly(ε-caprolactone-co-γ-dimethyl maleamidic acid -ε-caprolactone) (mPEG-b-P(CL-co-DCL)) bearing different amounts of acid-labile ß-carboxylic amides on the polyester moiety were synthesized. The chain structure and chemical composition of copolymers were characterized by (1)H NMR, Fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). mPEG-b-P(CL-co-DCL) with critical micellar concentrations (CMCs) of 3.2-6.3 µg/mL could self-assemble into stable micelles in water with diameters of 100 to 150 nm. Doxorubicin (DOX), a cationic hydrophobic drug, was successfully encapsulated into the polymer micelles, achieving a very high loading content due to electrostatic interaction. Then the stability, charge-conversional behavior, loading and release profiles, cellular uptake and in vitro cytotoxicity of free drug and drug-loaded micelles were evaluated. The ß-carboxylic amides functionalized polymer micelles are negatively charged and stable in neutral solution but quickly become positively charged at pH 6.0, due to the hydrolysis of ß-carboxylic amides in acidic conditions. The pH-triggered negative-to-positive charge reversal not only resulted in a very fast drug release in acidic conditions, but also effectively enhanced the cellular uptake by electrostatic absorptive endocytosis. The MTT assay demonstrated that mPEG-b-P(CL-co-DCL) micelles were biocompatible to HepG2 cells while DOX-loaded micelles showed significant cytotoxicity. In sum, the introduction of acid-labile ß-carboxylic amides on the polyester block in mPEG-b-P(CL-co-DCL) exhibited great potentials for the modifications in the stability in blood circulation, drug solubilization, and release properties, as well as cell internalization and intracellular drug release.

Self-regulated multifunctional collaboration of targeted nanocarriers for enhanced tumor therapy.

Exploring ideal nanocarriers for drug delivery systems has encountered unavoidable hurdles, especially the conflict between enhanced cellular uptake and prolonged blood circulation, which have determined the final efficacy of cancer therapy. Here, based on controlled self-assembly, surface structure variation in response to external environment was constructed toward overcoming the conflict. A novel micelle with mixed shell of hydrophilic poly(ethylene glycol) PEG and pH responsive hydrophobic poly(ß-amino ester) (PAE) was designed through the self-assembly of diblock amphiphilic copolymers. To avoid the accelerated clearance from blood circulation caused by the surface exposed targeting group c(RGDfK), here c(RGDfK) was conjugated to the hydrophobic PAE and hidden in the shell of PEG at pH 7.4. At tumor pH, charge conversion occurred, and c(RGDfK) stretched out of the shell, leading to facilitated cellular internalization according to the HepG2 cell uptake experiments. Meanwhile, the heterogeneous surface structure endowed the micelle with prolonged blood circulation. With the self-regulated multifunctional collaborated properties of enhanced cellular uptake and prolonged blood circulation, successful inhibition of tumor growth was achieved from the demonstration in a tumor-bearing mice model. This novel nanocarrier could be a promising candidate in future clinical experiments.

Integrin-targeted zwitterionic polymeric nanoparticles with acid-induced disassembly property for enhanced drug accumulation and release in tumor.

Reasonably structural design of nanoparticles (NPs) to combine functions of prolonged systemic circulation, enhanced tumor targeting and specific intracellular drug release is crucial for antitumor drug delivery. Combining advantages of Arg-Gly-Asp (RGD) for active tumor targeting, zwitterionic polycarboxybetaine methacrylate (PCB) for prolonged systemic circulation, poly(2-(diisopropylamino) ethyl methacrylate) (PDPA) for acid-triggered intracellular release, novel RGD-PCB-b-PDPA (RGD-PCD) block copolymers were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization and followed by functionalization with RGD. Doxorubicine (DOX) was encapsulated within the RGD-PCD NPs as model medicine (RGD-PCD/DOX NPs). With ultra pH-sensitivity of PDPA, the drug release was restrained at pH 7.4 for only 24% within 36 h, which was increased to 60% at pH 6.0 within 24 h, and released more rapidly at pH 5.0 for 100% within 5 h, indicating that the RGD-PCD/DOX NPs were able to turn drug release "off" at neutral pH (e.g., systemic circulation) whereas "on" under acidic conditions (e.g., inside endo/lysosomes). Furthermore, the results of fluorescence microscopy and flow cytometry analysis demonstrated improved internalization of RGD-PCD/DOX NPs in HepG2 cells via integrin-mediated endocytosis with rapid DOX release intracellularly. Consequently, the RGD-PCD/DOX NPs showed considerable cytotoxicity against HepG2 and HeLa cells in comparison with free DOX. Importantly, the RGD-PCD/DOX NPs exhibited little protein adsorption property with excellent serum stability, which led to prolonged systemic circulation and enhanced tumor accumulation in tumor-bearing nude mice. Therefore, this multifunctional RGD-PCD NPs, which represented the flexible design approach, showed great potential for the development of novel nanocarriers in tumor-targeted drug delivery.

Synthesis, biodistribution, and imaging of PEGylated-acetylated polyamidoamine dendrimers.

Polyamidoamine (PAMAM) dendrimers have been widely used as drug carriers, non-viral gene vectors and imaging agents. However, the use of dendrimers in biological system is constrained because of inherent toxicity and organ accumulation. In this study, the strategy of acetylation and PEGylation-acetylation was used to minimize PAMAM dendrimers toxicities and to improve their biodistribution and pharmacokinetics for medical application. PEGylated-acetylated PAMAM (G4-Ac-PEG) dendrimers were synthesized by PEGylation of acetylated PAMAM dendrimer of generation 4 (G4) with acetic anhydride and polyethylene glycol (PEG) 3.4 k. To investigate the cytotoxicity and in vivo biodistribution of the conjugates, in vitro cell viability analysis, Iodine-125 (125I) imaging, tissue distribution and hematoxylin-eosin (HE) staining were performed. We find that acetylation and PEGylation-acetylation essentially eliminates the inherent dendrimer cytotoxicity in vitro. Planar gamma (gamma) camera imaging revealed that all the conjugates were slowly eliminated from the body, and higher abdominal accumulation of acetylation PAMAM dendrimer was observed. Tissue distribution analysis showed that PEGylated-acetylated dendrimers have longer blood retention and lower accumulation in organs such as the kidney and liver than the non-PEGylated-acetylated dendrimers, but acetylation only can significantly increase the accumulation of G4 in the kidney and decrease the concentration in blood. Histology results reveal that no obvious damage was observed in all groups after high dose administration. This study indicates that PEGylation-acetylation could improve the blood retention, decrease organ accumulation, and improve pharmacokinetic profile, which suggests that PEGylation-acetylation provides an alternative method for PAMAM dendrimers modification.

Maintenance of amyloid ß peptide homeostasis by artificial chaperones based on mixed-shell polymeric micelles.

The disruption of Aß homeostasis, which results in the accumulation of neurotoxic amyloids, is the fundamental cause of Alzheimer's disease (AD). Molecular chaperones play a critical role in controlling undesired protein misfolding and maintaining intricate proteostasis in vivo. Inspired by a natural molecular chaperone, an artificial chaperone consisting of mixed-shell polymeric micelles (MSPMs) has been devised with tunable surface properties, serving as a suppressor of AD. Taking advantage of biocompatibility, selectivity toward aberrant proteins, and long blood circulation, these MSPM-based chaperones can maintain Aß homeostasis by a combination of inhibiting Aß fibrillation and facilitating Aß aggregate clearance and simultaneously reducing Aß-mediated neurotoxicity. The balance of hydrophilic/hydrophobic moieties on the surface of MSPMs is important for their enhanced therapeutic effect.

Influence of restorative materials on the mechanical properties of maxillary first molars with different degrees of cryptic fractures and defects: A finite element analysis.

This study aimed to apply finite element analysis to evaluate the effects of pile materials with different elastic moduli and cement materials on the stress distribution between the remaining tooth tissue and cryptic fracture defects. A three-dimensional finite element model was established for 20 maxillary first molars with hidden fissures and mesial tongue-tip defects. Two levels of hidden cracks and three types of pile and adhesive materials were used in the design. The stress distribution and maximum stress peak in the remaining tooth tissue and crack defects were determined by simulating the normal bite, maximum bite, and lateral movement forces. When titanium posts, zinc phosphate binders, and porcelain crowns were used to repair the two types of deep cracked teeth, the maximum principal stress at the crack and dentin was the smallest. As the crack depth increased, the maximum principal stress of the residual dentin and crack defects increased.

Engineering biomimetic nanosystem targeting multiple tumor radioresistance hallmarks for enhanced radiotherapy.

Tumor cells establish a robust self-defense system characterized by hypoxia, antioxidant overexpression, DNA damage repair, and so forth to resist radiotherapy. Targeting one of these features is insufficient to overcome radioresistance due to the feedback mechanisms initiated by tumor cells under radiotherapy. Therefore, we herein developed an engineering biomimetic nanosystem (M@HHPt) masked with tumor cell membranes and loaded with a hybridized protein-based nanoparticle carrying oxygens (O2) and cisplatin prodrugs (Pt(IV)) to target multiple tumor radioresistance hallmarks for enhanced radiotherapy. After administration, M@HHPt actively targeted and smoothly accumulated in tumor cells by virtue of its innate homing abilities to realize efficient co-delivery of O2 and Pt(IV). O2 introduction induced hypoxia alleviation cooperated with Pt(IV) reduction caused glutathione consumption greatly amplified radiotherapy-ignited cellular oxidative stress. Moreover, the released cisplatin effectively hindered DNA damage repair by crosslinking with radiotherapy-produced DNA fragments. Consequently, M@HHPt-sensitized radiotherapy significantly suppressed the proliferation of lung cancer H1975 cells with an extremely high sensitizer enhancement ratio of 1.91 and the progression of H1975 tumor models with an excellent tumor inhibition rate of 94.7%. Overall, this work provided a feasible strategy for tumor radiosensitization by overcoming multiple radioresistance mechanisms.

Heme-Mimetic Photosensitizer with Iron-Targeting and Internalizing Properties for Enhancing PDT Activity and Promoting Infected Diabetic Wound Healing.

The management of multibacterial infections remains clinically challenging in the care and treatment of chronic diabetic wounds. Photodynamic therapy (PDT) offers a promising approach to addressing bacterial infections. However, the limited target specificity and internalization properties of traditional photosensitizers (PSs) toward Gram-negative bacteria pose significant challenges to their antibacterial efficacy. In this study, we designed an iron heme-mimetic PS (MnO2@Fe-TCPP(Zn)) based on the iron dependence of bacteria that can be assimilated by bacteria and retained in different bacteria strains (Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus) and which shows high PDT antibacterial efficacy. For accelerated wound healing after antibacterial treatment, MnO2@Fe-TCPP(Zn) was loaded into a zwitterionic hydrogel with biocompatibility and antifouling properties to form a nanocomposite antibacterial hydrogel (PSB-MnO2@Fe-TCPP(Zn)). In the multibacterial infectious diabetic mouse wound model, the PSB-MnO2@Fe-TCPP(Zn) hydrogel dressing rapidly promoted skin regeneration by effectively inhibiting bacterial infections, eliminating inflammation, and promoting angiogenesis. This study provides an avenue for developing broad-spectrum antibacterial nanomaterials for combating the antibiotic resistance crisis and promoting the healing of complex bacterially infected wounds.

A Dual-Channel Ca2+ Nanomodulator Induces Intracellular Ca2+ Disorders via Endogenous Ca2+ Redistribution for Tumor Radiosensitization.

Tumor cells harness Ca2+ to maintain cellular homeostasis and withstand external stresses from various treatments. Here, a dual-channel Ca2+ nanomodulator (CAP-P-NO) is constructed that can induce irreversible intracellular Ca2+ disorders via the redistribution of tumor-inherent Ca2+ for disrupting cellular homeostasis and thus improving tumor radiosensitivity. Stimulated by tumor-overexpressed acid and glutathione, capsaicin and nitric oxide are successively escaped from CAP-P-NO to activate the transient receptor potential cation channel subfamily V member 1 and the ryanodine receptor for the influx of extracellular Ca2+ and the release of Ca2+ in the endoplasmic reticulum, respectively. The overwhelming level of Ca2+ in tumor cells not only impairs the function of organelles but also induces widespread changes in the gene transcriptome, including the downregulation of a set of radioresistance-associated genes. Combining CAP-P-NO treatment with radiotherapy achieves a significant suppression against both pancreatic and patient-derived hepatic tumors with negligible side effects. Together, the study provides a feasible approach for inducing tumor-specific intracellular Ca2+ overload via endogenous Ca2+ redistribution and demonstrates the great potential of Ca2+ disorder therapy in enhancing the sensitivity for tumor radiotherapy.

Mitochondrial Localized In Situ Self-Assembly Reprogramming Tumor Immune and Metabolic Microenvironment for Enhanced Cancer Therapy.

The inherent immune and metabolic tumor microenvironment (TME) of most solid tumors adversely affect the antitumor efficacy of various treatments, which is an urgent issue to be solved in clinical cancer therapy. In this study, a mitochondrial localized in situ self-assembly system is constructed to remodel the TME by improving immunogenicity and disrupting the metabolic plasticity of cancer cells. The peptide-based drug delivery system can be pre-assembled into nanomicelles in vitro and form functional nanofibers on mitochondria through a cascade-responsive process involving reductive release, targeted enrichment, and in situ self-assembly. The organelle-specific in situ self-assemblyeffectively switches the role of mitophagy from pro-survival to pro-death, which finally induces intense endoplasmic reticulum stress and atypical type II immunogenic cell death. Disintegration of the mitochondrial ultrastructure also impedes the metabolic plasticity of tumor cells, which greatly promotes the immunosuppresive TME remodeling into an immunostimulatory TME. Ultimately, the mitochondrial localized in situ self-assembly system effectively suppresses tumor metastases, and converts cold tumors into hot tumors with enhanced sensitivity to radiotherapy and immune checkpoint blockade therapy. This study offers a universal strategy for spatiotemporally controlling supramolecular self-assembly on sub-organelles to determine cancer cell fate and enhance cancer therapy.