The yttrium, cerium and magnesium bis(trimethylsilyl)methyls [Ln[CH(SiMe3)2]3][Ln = Y (1), Ce (2)], and the known compound Mg[[CH(SiMe3)2]2 (C) and [Mg(mu-Br)[CH(SiMe3)2](OEt2)]2 (D) formed the crystalline nitrile adducts [1(NCBut)2] (5), [2(NCPh)] (6), [C(NCR)2][R = But (8), Ph (9), C6H3Me2-2,6 (10)] and [Mg(mu-Br)[CH(SiMe3)2](NCR)]2 [R = But (11), Ph (12), C6H3Me2-2,6 (13)], rather than beta-diketiminato-metal insertion products. The beta-diketiminato-cerium complex [Ce[(N(SiMe3)C(C6H4But-4))2CH][N(SiMe3)2]2] (16) was obtained from [Ce[N(SiMe3)2]3] and the beta-diketimine H[[N(SiMe3)C(C6H4But-4)]2CH]]. The cerium alkyl 2 and [Ln[CH(SiMe3)(SiMe2OMe)]3][Ln = Y (3), Ce (4)] were obtained from the appropriate lithium alkyl precursor and [Ce(OC6H2But2-2,6-Me-4)3] or LnCl3, respectively. Heating complex 3 with benzonitrile in toluene afforded 2,2-dimethyl-4,6-diphenyl-5-trimethylsilyl-1,3-diaza-2-silahexa-1,3-diene (7), a member of a new class of heterocycles. The X-ray structures of the crystalline compounds, D, [Mg[CH(SiMe3)2]2(OEt2)2], the known [Ce(Cl)[(N(SiMe3)C(Ph))2CH]2] (E) and 16 are reported. The cerium alkyl (like 1) has one close Ce...C contact for each ligand, attributed to a gamma-C-Ce agostic interaction. The Ln alkyls and have a trigonal prismatic arrangement of the chelating ligands (each of the same chirality at Calpha) around the metal. In an arene solution at 313 K exists as two isomers, as evident from detailed NMR spectroscopic experiments.

AIM:To investigate whether nicotinamide overload plays a role in type 2 diabetes. METHODS:Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N 1 -methylnicotinamide on glucose metabolism, plasma H2O2 levels and tissue nicotinamide adenine dinucleotide (NAD) contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively. RESULTS:Diabetic subjects had significantly higher plasma N 1 -methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects (0.89 ± 0.13 μmol/L vs 0.6 ± 0.13 μmol/L, P < 0.001). Cumulative doses of nicotinamide (2 g/kg) significantly increased rat plasma N 1 -methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by N 1 -methylnicotinamide. Moreover, cumulative exposure to N 1 -methylnicotinamide (2 g/kg) markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/ NADH ratio, and increased plasma H2O2 levels. Decrease in NAD/NADH ratio and increase in H2O2 generation were also observed in human erythrocytes after exposure to N 1 -methylnicotinamide in vitro . Sweating eliminated excessive nicotinamide (5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load). Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N 1 -methylnicotinamide clearance. CONCLUSION:These findings suggest that nicotinamide overload, which induced an increase in plasma N 1 -methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

Complexes [Ce(NR(2))(3)] (1) or [Ce(NR''(2))(3)] (2) were cerium(III) precursors to the X-ray characterised crystalline oligomeric oxygen-containing amidocerium(IV) compounds [{Ce(NR(2))(2)(mu-O)}(n)] (3, n = 2; 4, n = 3), [{Ce(NR''(2))(2)(mu-O)}(4)] (5), [{(R(2)N)(3)Ce}(2)(mu-[upper bond 1 start]OMOM[upper bond 1 end])] (6, M = Na; 7, M = K), [{(R(2)N)(3)CeOCe(NR(2))(2)}(2)(mu-[upper bond 1 start]OKOK[upper bond 1 end])] (8), and [{Ce(NR(2))(3)}(2)(mu-eta(2):eta(2)-O(2))].2C(n)H(2n+2) (9, n = 6; 9', n = 5) [R = SiMe(3), NR''(2) = TMP = [upper bond 1 start]NC(Me)(2)(CH(2))(3)C[upper bond 1 end]Me(2)]. Each was isolated in low, or for 5 very low, yield. Except for 4, the oxidising agent was O(2) at -27 degrees C in hexane (3, 6, 7, 8, 9), pentane (9'), or toluene (5), and a co-reagent for the alkali metal bis(trimethylsilyl)amido(oxy)cerate(iv)s was NaNR(2) (8) or KNR(2) (7, 8). From 1 and an equivalent portion of 2,6-(t)Bu(2)-benzoquinone after 5 weeks in pentane there was obtained the bis(amido)cyclotricer(IV)oxane 4. The NMR spectral solution chemical shifts for NR(2) groups of 3, 4, and 6-9 were consistent with each sample being diamagnetic and hence a Ce(IV) species. A transient amidocerium(IV) superoxide Ce(NR(2))(3)(eta(2)-O(2)) (J), or its TMP analogue, is considered to be the common first-formed intermediate in each case, while 4 is believed to have arisen from the adventitious hydrolysis of [{Ce(NR(2))(3)O}(2)((t)Bu(2)C(6)H(2)-1,4)].

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Hydrogels, as a representative of soft and biocompatible materials, have been widely used in biosensors, biomedical devices, soft robotics, and the marine industry. However, the ir-recoverability of hydrogels after dehydration, which causes the loss of original mechanical, optical, and wetting properties, has severely restricted their practical applications. At present, this critical challenge of maintaining hydrogels’ accurate character has attracted less attention. To address this, here we report a hydrogel based on synergistic effects to achieve both well-regulated rehydration and deswelling properties. The hydrogel after dehydration can quickly restore its original state both on the macro- and microscale. In addition, the hydrogel has excellent mechanical stability after several dehydration–rehydration cycles. All of these properties offer a possibility of water condition endurance and increase the service life. The robust property is attributed to the hydrophilic–hydrophobic and ionic interactions induced by the synergy of hydrophilic/oleophilic heteronetworks. Moreover, zwitterionic segments as hydrophilic network play a vital role in fabricating anti-biofouling hydrogels. The durable and reusable hydrogel may have promising applications for biomedical materials, flexible devices, and the marine industry.