The therapeutic effect of low-level laser on repair of osteochondral defects in rabbit knee

INTRODUCTION: Low level laser therapy (LLLT) has been shown to enhance collagen production and wound healing but its effect on cartilage repair from biomechanical point of view is not known yet. The aim of present study was to evaluate the biomechanical behaviour of repairing osteochondral defect in rabbits which received a pulsed low-level gallium-arsenide (Ga-As) laser irradiation. MATERIALS AND METHODS: Osteochondral defects with 5mm diameter and 4mm in depth induced by drilling in right femoral patellar grooves of 41 adolescent male rabbits. They were divided into experimental and control groups. Experimental group received pulsed Ga-As (890nm) laser irradiation with energy density of 4.8J/cm(2). The rabbits in control group received placebo LLLT with shut-down equipment. The control defects were allowed to heal spontaneously. Each group were divided into three subgroups: A, B and C. Subgroups A, B and C were sacrificed on 4, 8, and 16 weeks after surgery. The knee joint were removed, and the defects were examined biomechanically by in situ-indentation method. The thickness, instantaneous and equilibrium indentation stiffness was measured during the test. Data were analysed using ANOVA and independent sample t-test. RESULT: While no difference was observed in the repaired cartilage biomechanical properties among 4th, 8th, 16th weeks in study groups. The equilibrium indentation stiffness of experimental group was significantly higher in 8th week in comparison with control group. CONCLUSION: LLLT significantly enhances the stiffness of repairing tissue in the 8th week post injury in osteochondral defects in rabbits.     

On the on-line maintenance scheduling problem

A machine instantly serves requests but needs to undergo maintenance after serving a maximum of L requests. We want to maximize the number of requests served. In the on-line version, we prove that serving L requests before placing a maintenance is 0.5-competitive and is best possible for deterministic algorithms. We describe a 0.585-competitive randomized algorithm and show an upper bound of \(2L/(3L-1)\). We also analyze the empirical performance of various on-line algorithms on specific arrival distributions.     

Layered double hydroxides (LDHs): As efficient heterogeneous catalyst for the cyanosilylation of aromatic aldehydes

We report the first application of Layered Double Hydroxides (LDHs) as efficient and novel heterogeneous catalyst for the cyanosilylation of aldehydes with excellent yields and simple work up. The reaction between different aldehydes with electron-withdrawing and releasing groups and trimethylsilyl cyanide (TMSCN) proceeds in dry CH₂Cl₂ at room temperature in the presence of Mg-Al-Cu LDH. The catalyst recycled and reused for four times without loss of catalytic activity. The structures of all compounds were corroborated spectroscopically (¹H- and ¹³C-NMR, and elemental analysis). A plausible mechanism for this type of reaction is proposed.     

Synthesis of (E)-2-amino-N′-benzylidenehexahydroquinoline-3-carbohydrazide

Molecular Diversity - A one-pot, multi-component protocol for the synthesis of a new class of functionalized quinoline carbohydrazide derivatives via reaction of various anilines, dimedone,...     

Classical and Inverse Median Location Problems under Uncertain Environment

In this paper, we first consider the classical p-median location problem on a network in which the vertex weights and the distances between vertices are uncertain variables. The uncertainty distribution of the optimal objective value of the p-median problem is given and the concepts of the α-p-median, the most p-median and the expected p-median are introduced. Then, it is shown that the uncertain p-median problem is NP-hard on general networks. However, if the underlying network is a tree, an ef...     

One-pot synthesis of new functionalized 4H-chromen-4-ylidene derivatives

A simple synthesis of new series of functionalized chromene derivatives through an efficient, one-pot, multicomponent reaction of nitroketene N,S-acetals, salicylaldehydes, and cyanoacetohydrazide in ethanol at ambient temperature in good to high yields is reported. This novel efficient method has the advantages of mild reaction conditions, absence of catalyst, simple work-up, and the non-chromatographic purification of products.     

Multidimensional view of amyloid fibril nucleation in atomistic detail

Starting from a disordered aggregate, we have simulated the formation of ordered amyloid-like beta structures in a system formed by 18 polyvaline chains in explicit solvent, employing molecular dynamics accelerated by bias-exchange metadynamics. We exploited 8 different collective variables to compute the free energy of hundreds of putative aggregate structures, with variable content of parallel and antiparallel β-sheets and different packing among the sheets. This allowed characterizing in detail a possible nucleation pathway for the formation of amyloid fibrils: first the system forms a relatively large ordered nucleus of antiparallel β-sheets, and then a few parallel sheets start appearing. The relevant nucleation process culminates at this point: when a sufficient number of parallel sheets is formed, the free energy starts to decrease toward a new minimum in which this structure is predominant. The complex nucleation pathway we found cannot be described within classical nucleation theory, namely employing a unique simple reaction coordinate like the total content of β-sheets.     

Comparison of Flow Cytometry and ELASA for Screening of Proper Candidate Aptamer in Cell-SELEX Pool

Aptamers are single-stranded RNA or DNA, which bind to their target with high affinity and specificity. Method of isolating aptamers against cell surface protein is called cell-SELEX. Common approach for monitoring cell-SELEX developed aptamers is flow cytometry. Since flow cytometry is costly and requires sophisticated equipments, we suggested implementing easy access, high throughput enzyme-link apta-sorbent assay test (ELASA) to confirm the specificity of aptamers selected through cell-SELEX process. In this regard, we compared ELASA and flow cytometry techniques in order to screen potent candidate aptamers against A2780 Rcis cell line, which were selected by cell-SELEX. The obtained results demonstrated that both ELASA and flow cytometry are identical in terms of sensivity and precision for aptamers selection. Then it could be concluded that ELASA method could be used as a versatile, inexpensive procedure for in vito evaluation of isolated aptamers from cell-SELEX based process.     

The NMR spectra of porphyrins—12: 13C and proton NMR spectra of the zinc(ii)coproporphyrin isomers2

The ¹³C and proton NMR spectra of the zinc(II) complexes of the tetramethyl esters of the four coproporphyrin type isomers are reported and assigned. Effects of aggregation phenomena on these shifts are discussed and a method involving addition of a slight excess of pyrrolidine is proposed for measurement of the spectra of the “monomeric” species; spectra obtained under these conditions are capable of simple, straight-forward interpretation and assignment in terms of molecular symmetry. Thus, a facile distinction between the type isomers is obtained.The “monomer” chemical shifts so derived allow consistent SCS parameters to be derived. The C_β-Me SCS are shown to be related to the bond order of the C_β-C_β bond in the porphyrin ring, and are thus quite different from the corresponding SCS in pyrroles.Aggregation shifts in the ¹³C and proton spectra are shown to be consistent with the presence of “stacked” aggregates with the ring current of one molecule affecting the other, together with an additional effect on the chemical shifts of the meso carbons, which is probably steric in origin.