Presence of Microplastics in Four Types of Shellfish Purchased at Fish Markets in Okayama City, Japan.

The worldwide microplastic pollution in our environment is a matter of great concern. Harmful effects of plastics have been reported in various types of organisms including murine animals. We examined the presence of microplastics in four types of shellfish purchased from fish markets in Okayama, Japan and served to the public: short-neck clam (Ruditapes philippinarum, asari in Japanese), hard-shell clam (Meretrix lusoria, hamaguri), brackishwater clam (Cyrenidae, shijimi), and oyster (Crassostrea gigas, kaki). Our analyses demonstrated that approx. 3 pieces of microplastics were present per single shellfish, based on the division of the total number of pieces of microplastic obtained from all 4 types of shellfish by the total number of shellfish examined. Since health problems in humans due to microplastics have not yet been confirmed, further examinations of the effects of ingested microplastics are needed.

Cytotoxic Effects of Alcohol Extracts from a Plastic Wrap (Polyvinylidene Chloride) on Human Cultured Liver Cells and Mouse Primary Cultured Liver Cells.

An increasing accumulation of microplastics and further degraded nanoplastics in our environment is suspected to have harmful effects on humans and animals. To clarify this problem, we tested the cytotoxicity of two types of plastic wrap on human cultured liver cells and mouse primary cultured liver cells. Alcohol extracts from plastic wrap, i.e., polyvinylidene chloride (PVDC), showed cytotoxic effects on the cells. Alcohol extracts of polyethylene (PE) wrap were not toxic. The commercially available PVDC wrap consists of vinylidene chloride, epoxidized soybean oil, epoxidized linseed oil as a stiffener and stabilizer; we sought to identify which component(s) are toxic. The epoxidized soybean oil and epoxidized linseed oil exerted strong cytotoxicity, but the plastic raw material itself, vinylidene chloride, did not. Our findings indicate that plastic wraps should be used with caution in order to prevent health risks.

Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand.

Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of gem-dichromiomethane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive gem-dimetalloalkane species. The isolated gem-dichromiomethane complex acted as a storable silylmethylidene carbene equivalent, with reactivity that could be changed dramatically upon addition of a Lewis acid (ZnCl2) and a base (TMEDA) to promote both silylalkylidenation of polar aldehydes and silylcyclopropanation of nonpolar alkenes. Identification of a key reactive species also identified the catalytic version of these transformations and provided insights into the reaction mechanism. In contrast to Simmons-Smith cyclopropanation, the real reactive species for the current cyclopropanation was a chromiocarbene species, not a chromium carbenoid species.

Analgesic agents without gastric damage: design and synthesis of structurally simple benzenesulfonanilide-type cyclooxygenase-1-selective inhibitors.

In order to create novel analgesic agents without gastric disturbance, structurally simple cyclooxygenase-1 (COX-1) inhibitors with a benzenesulfonanilide skeleton were designed and synthesized. As a result, compounds 11f and 15a, which possess a p-amino group on the benzenesulfonyl moiety and p-chloro group on the anilino moiety, showed COX-1-selective inhibition. Moreover compound 11f, which is the most potent compound in this study showed more potent analgesic activity than that of aspirin at 30 mg/kg by po. The anti-inflammatory activity and gastric damage, however, were very weak or not detectably different from aspirin. Since the structure of our COX-1 inhibitors are very simple, they may be useful as lead compounds for superior COX-1 inhibitors as analgesic agents without gastric disturbance.

Titanium and zirconium complexes with non-salicylaldimine-type imine-phenoxy chelate ligands: syntheses, structures, and ethylene-polymerization behavior.

New Ti and Zr complexes that bear imine-phenoxy chelate ligands, [{2,4-di-tBu-6-(RCH=N)-C6H4O}2MCl2] (1: M = Ti, R = Ph; 2: M = Ti, R = C6F5; 3: M = Zr, R = Ph; 4: M = Zr, R = C6F5), were synthesized and investigated as precatalysts for ethylene polymerization. 1H NMR spectroscopy suggests that these complexes exist as mixtures of structural isomers. X-ray crystallographic analysis of the adduct 1HCl reveals that it exists as a zwitterionic complex in which H and Cl are situated in close proximity to one of the imine nitrogen atoms and the central metal, respectively. The X-ray molecular structure also indicates that one imine phenoxy group with the syn C=N configuration functions as a bidentate ligand, whereas the other, of the anti C=N form, acts as a monodentate phenoxy ligand. Although Zr complexes 3 and 4 with methylaluminoxane (MAO) or [Ph3C]+ [B(C6F5)4]-/AliBu3 displayed moderate activity, the Ti congeners 1 and 2, in association with an appropriate activator, catalyzed ethylene polymerization with high efficiency. Upon activation with MAO at 25 degrees C, 2 displayed a very high activity of 19900 (kg PE) (mol Ti)(-1) h(-1), which is comparable to that for [Cp2TiCl2] and [Cp2ZrCl2], although increasing the polymerization temperature did result in a marked decrease in activity. Complex 2 contains a C6F5 group on the imine nitrogen atom and mediated nonliving-type polymerization, unlike the corresponding salicylaldimine-type complex. Conversely, with [Ph3C]+ [B(C6F5)4]-/AliBu3 activation, 1 exhibited enhanced activity as the temperature was increased (25-75 degrees C) and maintained very high activity for 60 min at 75 degrees C (18740 (kg PE) (mol Ti)(-1) h(-1)). 1H NMR spectroscopic studies of the reaction suggest that this thermally robust catalyst system generates an amine-phenoxy complex as the catalytically active species. The combinations 1/[Ph3C]+ [B(C6F5)4]-/AliBu3 and 2/MAO also worked as high-activity catalysts for the copolymerization of ethylene and propylene.