Immunological Evaluation of Co‐Assembling a Lipidated Peptide Antigen and Lipophilic Adjuvants: Self‐Adjuvanting Anti‐Breast‐Cancer Vaccine Candidates

Co‐assembling vaccines composed of a lipidated HER2‐derived antigenic CH401 peptide and either a lipophilic adjuvant, Pam₃CSK₄, α‐GalCer, or lipid A 506, were evaluated as breast cancer vaccine candidates. This vaccine design was aimed to inherit both antigen multivalency and antigen‐specific immunostimulation properties, observed in reported self‐adjuvanting vaccine candidates, by using self‐assembly and adjuvant‐conjugated antigens. Under vaccination concentrations, respective lipophilic adjuvants underwent co‐assembly with lipidated CH401, which boosted the anti‐CH401 IgG and IgM production. In particular, α‐GalCer was responsible for the most significant immune activation. Therefore, the newly developed vaccine design enabled the optimization of adjuvants against the antigenic CH401 peptide in a simple preparatory manner. Overall, the co‐assembling vaccine design opens the door for efficient and practical self‐adjuvanting vaccine development.     

Total Synthesis,Stereochemical Revision,and Biological Assessment of Iriomoteolide-2a

Iriomoteolide-2a is a marine macrolide metabolite isolated from a cultured broth of the benthic dinoflagellate Amphidinium sp. HYA024 strain. This naturally occurring substance was reported to show remarkable cytotoxic activity against human cancer cell lines HeLa and DG-75 and in vivo antitumor activity against murine leukemia P388 cell line. Herein, the total synthesis, stereochemical revision, and biological assessment of iriomoteolide-2a are reported in detail. Total synthesis of the proposed structure 1 of iriomoteolide-2a featured a late-stage convergent assembly of three components by a Suzuki–Miyaura coupling, an esterification, and a ring-closing metathesis. However, the NMR data of synthetic 1 were not identical to those of the natural product. Careful analysis of the NMR data of the authentic material and synthesis/NMR analysis of appropriately designed model compounds led to consideration of four possible stereoisomers 2 – 5 as candidates for the correct structure. Accordingly, total syntheses of 2 – 5 were achieved by taking advantage of the convergent strategy, and comparison of the NMR spectra of synthetic 2 – 5 with those of the natural product led to the conclusion that 5 shows the correct relative configuration of iriomoteolide-2a. The absolute configuration of this natural product was finally established through chiral HPLC analysis of synthetic 5 /ent- 5 with the authentic sample. The antiproliferative activity of the synthetic compounds was assessed against HeLa and A549 cells to show that, in contrast to expectation, synthetic 5 and ent- 5 were only marginally active in these cell lines. This work clearly underscores the vital role of total synthesis in the establishment of the structure and biological activity of natural products.     

Cyclohexane photooxidation under visible light irradiation by WO3–TiO2 mixed catalysts

Research on Chemical Intermediates - Cyclohexane photocatalytic oxidation was performed over WO3 photocatalysts under visible light irradiation with molecular oxygen. Cyclohexanone and cyclohexanol...     

Photodecomposition of water with methane over titanium oxide photocatalysts modified with metal

Metal-loaded titanium oxide photocatalysts produced hydrogen in the photodecomposition of water vapor with methane in the flow reactor. Ag/TiO₂ has the highest activity in comparison with other metal-loaded catalysts. The experiment in the absence of methane indicated that methane could effectively function as a reducing reagent of water. The significant decrease in the hydrogen formation rate with the time on stream was observed under all reaction conditions. The recalcination and the hydrogen rereduction of the used catalyst led to the restoration of the activity of the hydrogen formation. The adsorption of products and/or reactants on the catalyst surface seemed to cause these deactivations of the hydrogen formation.     

Hexa‐ and Dodecanuclear Polyoxomolybdate Cyclic Compounds: Application toward the Facile Synthesis of Nanoparticles and Film Electrodeposition

Two new compounds based on O₃PCH₂PO₃^4? ligands and {Mo^V₂O₄} dimeric units have been synthesized and structurally characterized. The dodecanuclear Mo^V polyoxomolybdate species in (NH₄)₁₈[(Mo^V₂O₄)₆(OH)₆(O₃PCH₂PO₃)₆]?33 H₂O ( 1 ) is a cyclohexane‐like ring in a chair conformation with pseudo S₆ symmetry. In the solid state, the wheels align side by side, thus delimiting large rectangular voids. The hexanuclear anion in Na₈[(Mo^V₂O₄)₃(O₃PCH₂PO₃)₃(CH₃AsO₃)]? 19 H₂O ( 2 ) has a triangular framework and encapsulates a methylarsenato ligand. ³¹P NMR spectroscopic analysis revealed the stability of 2 in various aqueous media, whereas the stability of 1 depends on the nature of the cations present in solution. It has been evidenced that the transformation of 1 into 2 occurs in the presence of CH₃AsO₃^2? ions. This behavior shows that 1 can be used as a new precursor for the synthesis of Mo^V/diphosphonate systems. The two complexes were very efficient both as reductants of Pt and Pd metallic salts and as capping agents for the resulting Pt⁰ and Pd⁰ nanoparticles. The size of the obtained nanoparticles depends both on the nature of the polyoxometalate (POM; i.e., 1 or 2 ) and on the [metallic salt]/[POM] ratio. In all cases, X‐ray photoelectron spectroscopy (XPS) measurements have revealed the presence of Mo^VI species that stabilize the nanoparticles and the absence of Mo^V moieties. Diffuse‐reflectance FTIR spectra of the Pt nanoparticles show that the capping Mo^VI POMs are identical for both systems and contain the diphosphonato ligand. The colloidal solutions do not show any precipitate and the nanoparticles remain well‐dispersed for several months. The electrochemical reduction of Mo^V species was studied for 2 . Cyclic voltammetry alone and electrochemical quartz crystal microbalance coupled with cyclic voltammetry show the deposition of a film on the electrode surface during this reduction.     

Thermal decomposition of acrylamide from polyacrylamide

Ion-attachment mass spectrometry with a temperature-programed direct probe allows the detection of intact pyrolysis products. It, therefore, offers the opportunity to monitor directly thermal byproducts on a real-time basis and potentially to detect thermally unstable products. With this technique, we investigated the thermal decomposition of polyacrylamide (PAA). Pyrolysis of PAA at around 450?°C produces many products (e.g., amides, imides, nitriles, ketones, aldehydes, and acrylamide oligomers). Acrylamide, which is a possible carcinogen, is produced abundantly in various industries, and, therefore, continues to be a cause for concern. We also investigated the kinetics of the thermal decomposition of PAA, and observed that the degradation of acrylamide obeys Arrhenius kinetics, which allowed us to correlate the rate constant with the absolute temperature and the activation energy. The activation energy of thermal decomposition was calculated from selected ion-monitoring curves of acrylamide.