Computer-aided quantification of focal cartilage lesions of osteoarthritic knee using MRI

Noninvasive assessment of articular cartilage using magnetic resonance imaging (MRI) has gained popularity in the diagnosis of osteoarthritis (OA), a condition that affects 20 million Americans. Focal cartilage lesions, a defect found in roughly 19% of the OA population, currently can only be evaluated with confidence using minimally invasive arthroscopy. This article presents a computer-aided procedure using MRI to quantify focal cartilage lesions and aims to support clinical practices of diagnosis and monitoring of lesion progress. Upon a local minima search for identifying focal lesions, the proposed gradient peak method outlines lesion boundaries and then generates morphological properties, such as lesion volume and lesion area. The procedure was evaluated using simulated and in vivo data. First, a simulated lesion was created and analyzed, and the results were compared with the exact solutions. Second, an in vivo evaluation was carried out on seven human knees in which nine focal lesions were identified and quantified. Three of the subjects had follow-up analyses, at either 1 or 2 years. Finally, in an attempt to characterize local biochemical changes underlying focal lesions, MR-derived T2 values of defective cartilage within the lesion boundaries were examined and compared with the values of adjacent cartilage compartments.     

Cardinal Functions on Initial Chain Algebras on Pseudotrees

Initial chain algebras on pseudotrees generalize the notion of an interval algebra on a linear order. Many relationships which hold between the various cardinal functions on interval algebras also hold for initial chain algebras. In particular, for initial chain algebras on pseudotrees, depth equals tightness, spread equals hereditary Lindelöf degree, irredundance equals the cardinality of the algebra, and incomparability equals hereditary cofinality. For interval algebras, Rubin showed that any subalgebra of regular uncountable cardinality contains either a chain of size or a pairwise incomparable family of size . This result holds for initial chain algebras as well.     

‘Morphs’ (MRFs): metal-reversible folding domains for differential IgG binding

BACKGROUND: Selective recognition and binding of IgG molecules is the basis for a host of immunological and affinity purification techniques. Capture of an IgG in these procedures relies chiefly on its interaction with one of a variety of reengineered bacterial receptors which bind to the Fc region of IgG molecules with very high affinity. While this interaction is extremely efficient in trapping IgG molecules, the tight interaction between the binding partners often requires denaturing conditions for disruption of the complex, which can adversely affect the yield of purified IgG and also limit the lifetime of the receptor matrix. An effective receptor/IgG binding system which could be modulated by less extreme conditions is of considerable general interest. RESULTS: We describe the properties of a series of modified Fc receptor domains which are competent to bind IgG with high affinity but which can be reversibly unfolded upon addition of modest amounts of transition metal ions. Data are presented demonstrating loss of the secondary structural content of the domains as a function of increasing metal concentration, with a concomitant decrease in IgG binding affinity. Variants of the Fc receptor differing at a single amino acid position display increased sensitivity to metal-induced unfolding, while retaining comparable IgG binding ability in the absence of metal. CONCLUSIONS: The interaction of this series of Fc receptors with metal ions abolishes IgG binding, but removal of metal ions allows refolding of the domains with restoration of the IgG binding function. Examples of the utility and potential applications of these metal-modulated IgG binding domains are discussed.     

Synthesis,characterization and biological properties of novel ON donor bidentate Schiff bases and their copper(II) complexes

Four novel ON donor Schiff bases (E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol (HL₁),(E)-3-((4-(4-biphenyloxy)phenyliminomethyl)benzene-1,2-diol (HL₂), (E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol (HL₃), (E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol (HL₄) and their copper(II) complexes bis((E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₁)₂) bis((E)-3-((4-(4-biphenyloxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₂)₂), bis((E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₃)₂), bis((E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₄)₂) have been synthesized and characterized by spectroscopic (FTIR, NMR, UV–visible) and elemental analysis. The crystal structures of HL₁, HL₂, HL_3, and HL₄ have been determined, which reveal intramolecular N-H?O (HL₁, HL₂, HL_3, and HL₄) hydrogen bonds in the solid state. Keto-amine and enol-imine tautomerism is exhibited by the Schiff bases in solid and solution states. The Schiff bases and their copper(II) complexes have been screened for their biological activities. In antimicrobial assays (antibacterial and antifungal), HL₄ showed promising results against all strains through dual inhibition property while the rest of the compounds showed activity against selective strains. On the other hand, in cytotoxic, DPPH, and inhibition of hydroxyl (OH) free radical-induced DNA damage assays, the results were found significantly correlated with each other, i.e. the ligands HL₁ and HL₂ showed moderate activity while their complexes Cu(L₁)₂ and Cu(L₂)₂ exhibited prominent increase in activity. As the results of these assays are supporting each other, it represents the strong positive correlation and antioxidant nature of investigated compounds.     

Nanostructured nonionic thymidine nucleolipid self-assembly materials

Three nucleoside lipids have been synthesized: 3'-oleoylthymidine, 3',5'-dioleoylthymidine, and 3'-phytanoylthymidine. Differential scanning calorimetry and X-ray diffraction have been employed to characterize the physical properties of these neat lipids. Polarizing optical microscopy, small-angle X-ray scattering, and cryo-transmission electron microscopy techniques have been used to investigate the phase behavior in aqueous systems. Both oleoyl-based nucleoside lipids adopted a lamellar crystalline phase in the neat form at room temperature, and the phytanoyl derivative exhibited a fluid isotropic phase. Under excess water conditions, the presence of one branched (phytanoyl) or one unsaturated (oleoyl) chain promoted the formation of a liquid-crystalline lamellar phase at physiological temperatures. In contrast, the 3',5'-dioleoylthymidine derivative is nonswelling and does not exhibit lyotropic liquid-crystalline phase behavior. The nucleolipids' propensity for DNA-type binding and recognition has been evaluated by using a monolayer system to measure surface pressure-area isotherms in a Langmuir trough and indicates that the nucleoside base is available for nonspecific hydrogen bonding in the monolayer liquid expanded state for the single-chain nucleolipids but not for the dual-chain amphiphile.     

Pharmacological interactions of essential oil constituents on the viability of micro-organisms

Complex interactions between numerous components of essential oils often contribute to the pharmacological effect and therapeutic outcome. To further elucidate these interactions, several essential oil constituents (EOCs) were combined in different ratios and their inhibitory effects on the growth of bacteria and yeast determined using the minimum inhibitory concentration (MIC) microplate assay. When combined and tested against Candida albicans, (+)-beta-pinene interacted antagonistically with (-)-menthone (sigmaFIC(T) = 9.80), but synergistically with 1,8-cineole (sigmaFIC(T) = 0.35). Against Escherichia coli, the combination of E- and Z-(+/-)-nerolidol and geranyl acetate displayed an additive interaction (sigmaFIC(T) = 1.04); while a variable interaction was observed between E- and Z-(+/-)-nerolidol and eugenol with antagonism and synergy being observed at different ratios of each EOC. The combination of either carvacrol or eugenol with an antimicrobial agent (ciprofloxacin or amphotericin B) resulted in synergistic interactions against all microorganisms tested. These favourable results further support the use of essential oil constituents as adjuvants in the development of a new generation of phytopharmaceuticals that can be used in combination with synthetic drugs against drug-resistant microorganisms.     

Asymptotic stability in nonlinear elastic materials with dissipation

This paper is concerned with the effects of dissipation on classical solutions of the displacement and mixed initial-boundary value problems for a nonlinear elastic material. A proof of the asymptotic stability of the null solution in three dimensions is presented and the necessary assumptions are carefully discussed. The derivation of an analogous result for non-zero equilibrium solutions of the one-dimensional problem completes this work.