Anterior cruciate ligament graft impingement against the posterior cruciate ligament: diagnosis using MRI plus three-dimensional reconstruction software

OBJECTIVE: The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against the posterior cruciate ligament (PCL) with the knee in an extended position, which arthroscopy cannot detect. MATERIALS AND METHODS: Ten normal knees and 30 ACL-reconstructed knees were assessed using MR imaging. The three-dimensional reconstruction of the ACL, PCL, femur and tibia were carried out using commercially available three-dimensional reconstruction software. Anterior cruciate ligament impingement against the PCL was graded into three categories: Grade 1, some space between the ligaments; Grade 2, no space between the ligaments, and the reconstructed ACL ran straight; and Grade 3, the reconstructed ACL did not run straight. The angle of the reconstructed ACL against the tibial plateau was also measured. RESULTS: All normal knees were classified as Grade 1. The 30 reconstructed knees were classified as follows: Grade 1, 12 cases; Grade 2, 7 cases; and Grade 3, 11 cases. The mean angle of the Grade 3 reconstructed ACL knees was significantly more vertical against the tibia as compared with the Grade 1 knees (P<.05). The postoperative KT-2000 side-to-side difference of the Grade 3 knees (2.8+/-4.5 mm) was larger than that of the Grade 1 knees (0.2+/-1.7 mm) and Grade 2 knees (-0.6+/-2.2 mm), but no statistically significant difference could be detected between the three groups in the postoperative KT-2000 data. CONCLUSION: This method is useful to evaluate ACL impingement against PCL, which cannot be detected by conventional arthroscopy during the operation. The surgeon should pay careful attention to the coronal angle of the reconstructed ACL.     

The Effect of Radiation on Transmission of Quasi-Periodic Multi-Layer Planar Dielectric Gratings

The transmission characteristics of quasi-periodic multi-layer planar dielectric gratings are systematically investigated by a method that combines the multimode network theory with rigorous mode matching method. The effect of radiation on the transmission characteristics of the multi-layer dielectric gratings is discussed in details, and some guidelines are given for accurate design of the gratings.     

Numerical Analysis of Microcavities on Two-dimensional Photonic Crystals

We analyzed the frequency and quality factor of microcavities on a two-dimensional photonic crystal, using a Fourier series expansion method combined with perfectly matched layers (PMLs). Numerical examples are demonstrated and discussed to show that the resonant frequency and the quality factor Q values can be calculated by the present method using PMLs.     

Effect of a film layer on mono-divalent bi-ionic membrane potential

The bi-ionic potential generated across a standard cation exchange membrane was investigated in a mono-divalent bi-ionic system. Applying Henderson's theory to the film layer, the Nernst—Planck equation was solved in the film layer as well as in the membrane. The observed potentials were compared with the theoretically predicted values from parameters such as bulk concentrations, diffusion coefficients in the membrane and in solution, exchange capacity, corrected molar selectivity coefficient, and film layer thickness. The calculated potentials were not always in agreement with the experimental values, but reproduced properly the trend of potential change with concentration and stirring rate. The constituent potentials, i.e. the diffusion potentials in the film layer and in the membrane and the interfacial potentials, are also discussed. In the sodium—calcium bi-ionic system, the primary contribution to the total membrane potential was not the diffusion potential in the film layers and in the membrane, but the sum of two interfacial potentials. p]In the case of membrane-diffusion control, the bi-ionic potential was confirmed to follow the equation of Helfferich.     

Reverse‐Selective Microporous Membrane for Gas Separation

Sort the bigs from the smalls : Reverse‐selective membranes, through which bigger molecules selectively permeate, are attractive for developing chemical processes. A new adsorption‐based reverse‐selective membrane that utilizes a Na cation occluded in a zeolitic framework is presented. The membrane developed enables the selective permeation and separation of bigger polar molecules, such as methanol and water, from hydrogen above 473 K.

     

Photo-acoustic spectroscopy of polymer with infrared free electron laser

We have been proposing a new photo acoustic spectroscopy (PAS) method with an infrared free electron laser (IR-FEL). The IR-FEL is a continuous tunable laser in the lasing wavelength in an finger-print wavelength region with high peak power. The IR-FEL resonantly induce the specific molecular vibration of the samples, resulting casue the photo acoustic pheneomena with high sensitivity. Thus, the new PAS method with the IR-FEL is high sensitive analysis method applicable to low absorbance measurement. In this study we show the feasibility of application of the MIR-FEL to the photon source of the PAS method by measuring the PAS spectrum of polymers such as a poly ethylene terephthalate (PET) film. In addition, we construct an imaging system of the FEL-PAS to make a map of the PAS signal with a high spatial resolution that is a diffraction limit of the IR-FEL.     

Ion-specific swelling behaviors of partially quaternized poly(4-vinyl pyridine) gel

Swelling degrees of partially quaternized poly(4-vinyl pyridine) (p.q.P4VP) were measured as functions of the degree of quaternization (D.Q.: 5, 10, 15, 30, and 50 mol%), salt concentration (0–4 M), and salt species (KF, LiCl, NaCl, KCl, CsCl, MgCl₂, KBr, LiSCN, KSCN, Na₂SO₄, and MgSO₄) to study ion effects on the three kinds of interactions involved with p.q.P4VP in aqueous systems, i.e., electrostatic interaction, hydrogen bonding to the nitrogen of the pyridine ring, and hydrophobic interaction, as well as to estimate the relative contributions of the respective ion effects to gel swelling. Upon addition of salts at the lowest salt concentration studied (0.01 M), p.q.P4VP gels, except for one with D.Q.=10%, significantly deswelled depending on the counterion species; the lowest swelling degree was observed for the thiocyanates and the highest one for KF. In the higher salt concentration region (≧1 M) where electrostatic interactions might well be screened, however, some salt systems (e.g., LiCl, KSCN) showed swelling with increased salt concentration, contrary to the common behavior of usual ionic gels. These ion-specific swelling behaviors were interpreted as being caused by additive ionic effects on the three kinds of interactions.     

Structure determination of a peptide model of the repeated helical domain in Samia cynthia ricini silk fibroin before spinning by a combination of advanced solid-state NMR methods

Fibrous proteins unlike globular proteins, contain repetitive amino acid sequences, giving rise to very regular secondary protein structures. Silk fibroin from a wild silkworm, Samia cynthia ricini, consists of about 100 repeats of alternating polyalanine (poly-Ala) regions of 12-13 residues in length and Gly-rich regions. In this paper, the precise structure of the model peptide, GGAGGGYGGDGG(A)(12)GGAGDGYGAG, which is a typical repeated sequence of the silk fibroin, was determined using a combination of three kinds of solid-state NMR studies; a quantitative use of (13)C CP/MAS NMR chemical shift with conformation-dependent (13)C chemical shift contour plots, 2D spin diffusion (13)C solid-state NMR under off magic angle spinning and rotational echo double resonance. The structure of the model peptide corresponding to the silk fibroin structure before spinning was determined. The torsion angles of the central Ala residue, Ala(19), in the poly-Ala region were determined to be (phi, psi) = (-59 degrees, -48 degrees ) which are values typically associated with alpha-helical structures. However, the torsion angles of the Gly(25) residue adjacent to the C-terminal side of the poly-Ala chain were determined to be (phi, psi) = (-66 degrees, -22 degrees ) and those of Gly(12) and Ala(13) residues at the N-terminal of the poly-Ala chain to be (phi, psi) = (-70 degrees, -30 degrees ). In addition, REDOR experiments indicate that the torsion angles of the two C-terminal Ala residues, Ala(23) and Ala(24), are (phi, psi) = (-66 degrees, -22 degrees ) and those of N-terminal two Ala residues, Ala(13) and Ala(14) are (phi, psi) = (-70 degrees, -30 degrees ). Thus, the local structure of N-terminal and C-terminal residues, and also the neighboring residues of alpha-helical poly-Ala chain in the model peptide is a more strongly wound structure than found in typical alpha-helix structures.