Hydroxyl-rich Schiff base ligands react with Mn(II) and Mn(III) salts in basic methanolic solution, generating monomeric Mn(IV) complexes. The general stoichiometry is MnL2, where L represents a dianionic, tridentate Schiff base ligand that uses one imine nitrogen, one phenolate oxygen, and one alkoxide oxygen atom to form a neutral octahedral complex. The molecular structure of Mn(SALADHP)2 (where H2SALADHP = l,3-dihydroxy-2-methyl-2-(salicylideneamino)propane) has been determined by X-ray crystallography. The compound crystallizes from DMF/ether in the monoclinic space group 2 /• (Z = 4, a = 10.676 (5) Á, b = 16.473 (10) Á, c = 17.541 (7) A, ß = 102.82 (4)°, V = 3008 (3) Á3), and the structure has been refined by using full-matrix least-squares methods to a final R = 0.076, J?w = 0.072 with 2186 data greater than 3a(I). Those complexes that form one fiveand one six-membered ring (where L can be H2SALAHE = 2-(salicylideneamino)-l-ethanol, H2SALAPDH = 1,3-dihydroxy-3-phenyl-2-(salicylideneamino)propane, H2SALATHM = tris(hydroxymethyl)(salicylideneamino)methane, and H2N02SALAPDH = 1,3-dihydroxy-3-(4-nitrophenyl)-2-(salicylideneamino)propane) are believed to be isostructural to Mn(SALADHP)2. The X-band EPR spectra, obtained at 90 K in DMF/methanol, show low-field features ranging between g = 4.32 and g = 5.45. The EPR spectrum for Mn(SALADHP)2 arises from a rhombically distorted S = 3/2 spin system with E/D = 0.22. The SALAHP ligand also forms mononuclear Mn(IV) complexes; however, it contains two six-membered chelate rings. All complexes exhibit roomtemperature solid-state and solution magnetic moments in the range 3.80-4.3 µ , further substantiating the Mn(IV) formulation. The EPc values for the complexes in Me2SO range between -320 and -480 mV vs. Ag/AgCl. The stabilization of the Mn(IV) oxidation state by alkoxide oxygen ligation is demonstrated by the nearly 1 V more negative reduction potential of these compounds compared to that of another compound, bis(salicylato)(bipyridine)manganese(IV), with an N204 coordination environment.
The intervertebral disc degeneration (IVDD)-related diseases occur in more than 90% of the population older than 50 years. Owing to the lack of understanding of the cellular mechanisms involved in IVDD formation effective treatment options are still unavailable. Primary cilia are microtubule-based organelles that play important roles in the organ development. Intraflagellar transport (IFT) proteins are essential for the assembly and bidirectional transport within the cilium. Role of cilia and IFT80 protein in intervertebral disc (IVD) development, maintenance, and degeneration are largely unknown. Using cilia-GFP mice, we found presence of cilia on growth plate (GP), cartilage endplate (EP) annulus fibrosus (AF), and nucleus pulposus (NP) with varying ciliary length. Cilia length in NP and AF during IVDD were significantly decreased. However, cilia numbers increased by 63% in AF during repair. Deletion of IFT80 in type II collagen-positive cells resulted in cilia loss in GP and EP, and disrupted IVD structure with disorganized and decreased GP, EP, and internal AF (IAF), and less compact and markedly decreased gel-like matrix in the NP. Deletion of IFT80 in type I collagen-positive cells led to a disorganized outer AF (OAF) with thinner, loosened, and disconnected fiber alignment. Mechanistic analyses showed that loss of IFT80 caused a significant increase in cell apoptosis in the IVD, and a marked decrease in expression of chondrogenic markers -type II collagen, sox9, aggrecan, and hedgehog (Hh) signaling components, including Gli1 and Patch1 in the IVD of IFT80 fl/fl ; Col2-creERT mice, and Gli1 and Patch1 expression in the OAF of IFT80 fl/fl ; Col1-creERT mice. Interestingly, Smoothened agonist-SAG rescued OAF cell proliferation and osteogenic differentiation. Our findings demonstrate that ciliary IFT80 is important for the maintenance of IVD cell organization and function through regulating the cell survival and Hh signaling. K E Y W O R D S annulus fibrosus, IFT80, intervertebral disc degeneration, nucleus pulposus, primary cilia 6742 | LI et aL.
In aiming for better access to climate change information and for providing climate service, it is important to obtain reliable high-resolution temperature simulations. Systematic comparisons are still deficient between statistical and dynamic downscaling techniques because of their inherent unavoidable uncertainties. In this paper, 20 global climate models (GCMs) and one regional climate model [Providing Regional Climates to Impact Studies (PRECIS)] are employed to evaluate their capabilities in reproducing average trends of mean temperature (Tm), maximum temperature (Tmax), minimum temperature (Tmin), diurnal temperature range (DTR), and extreme events represented by frost days (FD) and heat-wave days (HD) across China. It is shown generally that bias of temperatures from GCMs relative to observations is over ±1°C across more than one-half of mainland China. PRECIS demonstrates better representation of temperatures (except for HD) relative to GCMs. There is relatively better performance in Huanghuai, Jianghuai, Jianghan, south Yangzi River, and South China, whereas estimation is not as good in Xinjiang, the eastern part of northwest China, and the Tibetan Plateau. Bias-correction spatial disaggregation is used to downscale GCMs outputs, and bias correction is applied for PRECIS outputs, which demonstrate better improvement to a bias within ±0.2°C for Tm, Tmax, Tmin, and DTR and ±2 days for FD and HD. Furthermore, such improvement is also verified by the evidence of increased spatial correlation coefficient and symmetrical uncertainty, decreased root-mean-square error, and lower standard deviation for reproductions. It is seen from comprehensive ranking metrics that different downscaled models show the most improvement across different climatic regions, implying that optional ensembles of models should be adopted to provide sufficient high-quality climate information.
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