Discrimination of healthy and osteoarthritic articular cartilage by Fourier transform infrared imaging and Fisher's discriminant analysis.

Fourier transform infrared spectroscopic imaging (FTIRI) technique can be used to obtain the quantitative information of content and spatial distribution of principal components in cartilage by combining with chemometrics methods. In this study, FTIRI combining with principal component analysis (PCA) and Fisher's discriminant analysis (FDA) was applied to identify the healthy and osteoarthritic (OA) articular cartilage samples. Ten 10-µm thick sections of canine cartilages were imaged at 6.25µm/pixel in FTIRI. The infrared spectra extracted from the FTIR images were imported into SPSS software for PCA and FDA. Based on the PCA result of 2 principal components, the healthy and OA cartilage samples were effectively discriminated by the FDA with high accuracy of 94% for the initial samples (training set) and cross validation, as well as 86.67% for the prediction group. The study showed that cartilage degeneration became gradually weak with the increase of the depth. FTIRI combined with chemometrics may become an effective method for distinguishing healthy and OA cartilages in future.

[Study on the Anisotropy of Collagenours Fibers in Articular with Infrared Imaging].

Formalin solution has been widely used to solidify the organization of articular cartilage and prevent tissue decomposition in long-time measurement. However, it was rarely investigated that the structural anisotropy changes of collagen fiber (fixation) of articular cartilage when it was immersed in formalin. In this paper, Fourier transform infrared spectroscopic imaging with polarization technique was used to investigate the anisotropic structure change of collagen fiber of articular cartilage fixed in formalin through the absorbance change of Amide I and Amide II with immersing time and polarization direction. The degree of anisotropy of collagen fiber in cartilage was characterized with fitting related coefficient of absorbance. The anisotropy of Amide I and Amide II became stronger with immersing extension of articular cartilage in formalin, and the amide I showed more remarkable anisotropy. It was concluded that the formalin solution induced new crosslinks of collagen, which gradually strengthened the collagen fiber anisotropy and was helpful for the structural analysis of the articular cartilage. The study will be significant for the preparation, preservation and anisotropy research of cartilage specimen.

Discrimination of healthy and osteoarthritic articular cartilages by Fourier transform infrared imaging and partial least squares-discriminant analysis.

Fourier transform infrared imaging (FTIRI) combined with chemometrics algorithm has strong potential to obtain complex chemical information from biology tissues. FTIRI and partial least squares-discriminant analysis (PLS-DA) were used to differentiate healthy and osteoarthritic (OA) cartilages for the first time. A PLS model was built on the calibration matrix of spectra that was randomly selected from the FTIRI spectral datasets of healthy and lesioned cartilage. Leave-one-out cross-validation was performed in the PLS model, and the fitting coefficient between actual and predicted categorical values of the calibration matrix reached 0.95. In the calibration and prediction matrices, the successful identifying percentages of healthy and lesioned cartilage spectra were 100% and 90.24%, respectively. These results demonstrated that FTIRI combined with PLS-DA could provide a promising approach for the categorical identification of healthy and OA cartilage specimens.

3,3'-[(tert-Butoxy-carbon-yl)aza-nedi-yl]dipropanoic acid.

The title compound, C(11)H(19)NO(6), is an important inter-mediate for the synthesis of cephalosporin derivatives. The N atom is in a planar configuration. In the crystal, mol-ecules are linked into zigzag layers parallel to (100) by O-H⋯O hydrogen bonds.

trans-4-Nitro-phenyl 4-(tosyl-oxymeth-yl)cyclo-hexa-necarboxyl-ate.

The title compound, C(21)H(23)NO(7)S, is an important inter-mediate in the synthesis of poly(amido-amine) dendrimers. The cyclo-hexane ring adopts a chair conformation. The dihedral angle between the two aromatic rings is 69.5 (2)°. The mol-ecules are linked into a zigzag chain along the b axis by C-H⋯O hydrogen bonds.

1-[Bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl]-3-[bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl-methyl]imidazolium hexa-fluoro-phos-phate.

In the title compound, C(20)H(19)N(2) (+)·PF(6) (-), the two benzocyclo-butene units are essentially planar and they form dihedral angles of 38.0 (2) and 72.7 (2)°, with the central imidazolium ring. In the crystal structure, weak C-H⋯π and π--π stacking inter-actions [centroid-centroid distance = 3.742 (2) Å] contribute to the stability of the crystal structure. The PF(6) (-) ion is disordered over two positions with site occupancies of 0.869 (9) and 0.131 (9).

Ethyl 7-amino-1-cyclo-propyl-6-fluoro-8-meth-oxy-4-oxo-1,4-dihydro-quinoline-3-carboxyl-ate monohydrate.

In the title compound, C(16)H(17)FN(2)O(4)·H(2)O, the dihedral angle between the heterocyclic ring and the benzene ring is 5.77 (9)°, that between the heterocycle and the ethoxy-carbonyl plane is 15.5 (1)°, and that between the heterocyclic ring and the cyclopropane ring is 67.75 (13)°. In the crystal structure, mol-ecules are linked into a ribbon-like structure along the c axis by N-H⋯O and O-H⋯O hydrogen bonds.

cis-4-(Tosyl-oxymeth-yl)cyclo-hexa-ne-carboxylic acid.

The title compound, C(15)H(20)O(5)S, is an inter-mediate in the synthesis of novel amino-carboxylic acid derivatives. The cyclo-hexane ring exhibits a chair conformation. In the crystal structure, adjacent mol-ecules form dimers via O-H⋯O hydrogen bonds.

N-(2-Hydroxy-ethyl)-3,5-dinitro-benzamide.

The title compound, C(9)H(9)N(3)O(6), was synthesized by the condensation of methyl 3,5-dinitro-benzoate and 2-amino-ethanol. The non-centrosymmetric space group results in the formation of pseudo-chiral helices in the crystal structure, which exhibits a layer packing structure involving intra-molecular N-H⋯O and O-H⋯O inter-actions.

Euphorbia factor L(8): a diterpenoid from the seeds of Euphorbia lathyris.

THE TITLE COMPOUND [SYSTEMATIC NAME: (2S*,3S*,4R*,5R*,9S*,11S*,15R*)-5,15-diacet-oxy-3-nicotino-yloxy-14-oxolathyra-6(17),12(E)-diene], C(30)H(37)NO(7), was isolated from the seeds of Euphorbia lathyris. The tricyclic diterpenoid molecule contains an 11-membered ring, a five-membered ring exhibiting an envelope conformation and a three-membered ring. The 11-membered ring is cis-fused with the three-membered ring and trans-fused with the five-membered ring.