A less invasive Emax estimation method for weaning fromcardiac assistance

The maximum elastance of the ventricle (E_max) is a strong candidate for a quantitative index used for determination of the timing of weaning the patient from a left ventricular assist device (LVAD). The authors present a new and less invasive method for deriving E_max of the left ventricle under the LVAD assistance. In this method (the CoP method), E_max can be calculated from two different end-systolic points which are produced by changing the drive phase of LVAD without any vascular clamping and any direct measurement of the left ventricular volume. Animal experiments indicated that the CoP method is useful when the measured left ventricular flow and pressure are employed. Moreover, a new technique for estimating the left ventricular flow was developed to make the CoP method less invasive without direct measurement of the flow. The technique could considerably improve the estimation accuracy of the flow in the co-pulsation mode in comparison with the previous one proposed by the authors. However, it has been revealed that the estimation accuracy of the left ventricular flow was not globally high enough to apply the CoP method to clinical cases in spite of its much less invasiveness     

Reverse engineering of spatiotemporal patterns in the spatial prisoner’s dilemma

Many complex patterns are produced by the spatial prisoner’s dilemma, such as spatial games (Nature 1992;359:826–829) and spatial strategies (Artif Life Robotics 2004;9:139–143). We have studied the inverse problem of identifying a game by estimating the parameters in the payoff of the game from spatiotemporal patterns.     

Assessing cardiovascular dynamics during ventricular assistance.Use of fuzzy clustering techniques

The authors' group has recently developed an expert system realized by means of fuzzy logic algorithms for monitoring and malfunction diagnosis of the left ventricular assist device (LVAD), one of the many types of artificial hearts developed today. The system is named TOTOMES (Tohoku University and Toyohashi University of Technology, monitoring and estimation system). TOTOMES is suitable for clinical application because it operates in an online and realtime fashion on a widely used personal computer in Japan. This article introduces the structure and function of the TOTOMES and explains its techniques, such as multi-interrupt tasks and dynamic system identification; as well as fuzzy reasoning used for realizing state estimation, detection, and diagnosis of malfunctions; and monitoring for cardiovascular dynamics under ventricular assistance and the LVAD drive system     

Anti-mitogenic effects of sarpogrelate in cultured rat mesangial cells

We investigated the effects of the new 5-HT2A receptor antagonist, sarpogrelate, on DNA synthesis in renal mesangial cells stimulated with 5-HT in the presence and absence of platelet-derived growth factor (PDGF)-BB. Both 5-HT and PDGF-BB demonstrated a mitogenic effect on these cells. When mesangial cells were incubated in the absence of PDGF-BB, sarpogrelate inhibited DNA synthesis in these cells in a dose-dependent manner. In the presence of PDGF-BB, sarpogrelate had a weaker anti-mitogenic effect in mesangial cells stimulated with 5-HT. Sarpogrelate was cytotoxic at concentrations over 10(-5) M according to the results of LDH release assays, and it reduced the S1 phase in mesangial cells stimulated with 5-HT by a flow cytometry. These findings suggest that sarpogrelate may be effective in the treatment of some glomerulonephritis associated with mesangial cell proliferation.     

Potical Energy Gap and Below Gap Optical Absorption of Fullerene Films Measured By Constant Photocurrent Method and Photothermal Deflection Spectroscopy

CPM spectra of the fullerene film was measured to obtain the below gap absorption. The optical energy gap E_o was obtained by using the Tauc's plots. E_o did not change so much with the intercalated impurities. The absorption due to intercalated impurities was found below 1.6eV.     

Electric dichroism studies of the bonding of Co(III) chelate with synthetic polyelectrolytes

The interactions of bis-2-(2-pyridylazo)-1-naphthol Co(III), [Co(III) (αPAN)₂⁺], with five kinds of synthetic polyelectrolytes have been studied by spectrophotometric and transient electric dichroism measurements. The polyelectrolytes were: poly(styrene sulphonic acid) (PSS); poly(acrylic acid) (PAA); poly(l-glutamic acid) (PLG); $\text{poly}\text{(N}{}^{\mathrm{<mtext>e</mtext>}}\text{,N}{}^{\mathrm{<mtext>e</mtext>}}\text{-}\text{dicarboxylmethyl-}\text{l}\text{-lysine}$ (PDCML); and poly(l-lysine) (PLL). The equilibrium constant of the reaction:

with P = polyelectrolyte residue was determined spectrophotometrically: K₁ is > 10⁷ M^?1 (PSS); (1.4 ± 0.2) × 10⁴ M^?1 (PAA); (4.0 ± 0.4) × 10³ M^?1 (PLG); (1.4 ± 0.2) × 10⁶ M^?1 (PDCML); and < 10² M^?1 (PLL) at pH 6–8. From transient electric dichroism, the angle (ψ) between the αPAN plane and the polymer axis was determined to be 65° (PSS); 52° (PAA); 55° (PLG); and 52° (PDCML). The large K₁ and ψ values for PSS are ascribed to the hydrophobic interaction between the aromatic αPAN ring and the styrene sulphonate residues of PSS. Using stopped-flow electric dichroism measurements, rapid transfer of a bound Co(III) chelate from the PDCML to PSS chains was shown to occur.     

Effect of water-Insoluble Powder Addition on Physical Properties of Gelatin Gel

Water-insoluble powder is often dispersed in shells of commercial soft capsules for various reasons, but little reports have been published about the effect of powder addition on the physical properties of the gelatin gel. Glass powder, titanium oxide, calcium carbonate and γ-orizanol were used as model of powder. Changes of Young modulus obtained from the tensile test showed that any powder addition to the gelatin sheet made the gelatin sheet hard not by the surface effect of powder but by the volumetric effect of it. In this test, any powders had no effect on the tensile strength of the gelatin sheet because there was little interaction between each powder and the gelatin gel in the break point. The limiting strain was decreased a little up to the specific amount of each powder and then beyond the specific amount that decreased steeply in the case of glass powder and γ-orizanol. There might be a suitable range of the amount of powder for the gelatin sheet to keep the plastic flow similar to the gelatin sheet containing no powder. In this work, it was shown that the physical properties of the gelatin shell would be regulated by powder addition to the gelatin sheet.