Evaluation of thallium-201 myocardial emission computed tomography based on a comparison with postmortem findings

The correlative study of myocardial perfusion assessed by 201Tl myocardial ECT with the pathological finding of the heart was performed in 10 autopsied cases with mean age of 77 years old (range: 60-90 y). In 6 cases with myocardial infarction (MI) 7 perfusion defects were observed, that was, 3 in anteroseptal wall, 1 in anterolateral wall and 3 in posterior wall on the images of SPECT. Seven MIs were also found in postmortem examination. Six MIs were observed at autopsy corresponding to perfusion defect on SPECT images. In one myocardial perfusion defect at inferoposterior portion on SPECT, a non-transmural MI was found at anteroseptum. In one case with valvular disease a false positive result was obtained at posterior wall where neither myocardial necrosis nor fibrosis was observed at autopsy. This case had aortic stenosis due to bicuspid aortic valve by autopsy. The ventricle was divided into 16 segments in each of 4 short axial images to evaluate extent of MI. SPECT for extent of MI showed sensitivity of 81.9%, specificity of 96.0% and diagnostic accuracy of 92.5%. False negative segment was apt to be observed at the surrounding of non-transmural MI or basal half of left ventricle (LV) with transmural MI, while false positive segment was at posterior portion of basal half of LV. It was concluded that myocardial ECT was useful for evaluation of the site and extent of MI.     

An efficient 1,3-dipolar cycloaddition between aromatic selenoaldehydes and nitrile oxides or nitrile imines: an easy access to selenium-containing five-membered heterocyclic ring system

1,3-Dipolar cycloaddition between aromatic selenoaldehydes, generated by thermal retro Diels-Alder reaction of anthracene cycloadducts, and nitrile oxides or nitrile imines proceeded efficiently to give the corresponding [3+2] cycloadducts as a single isomer in good yields, being 1,4,2-oxaselenazoles or 1,3,4-selenadiazoles, respectively.     

Ion-pair adsorption film colorimetry — A new simple method for ppb level of aluminum ion in water sample

A new, highly sensitive and simple colorimetric method for trace aluminum(III) with 2,2-dihydroxyazobenzene, H₂L, is described, based on the ion-pair adsorption of the anionic Al chelate, [A1L₂ ^–, with crystal violet cation, CV⁺, on the surface of Polyvinylchloride film plasticized with dioctylphthalate. The blue violet species, CV⁺[A1L₂]^–, is enriched onto the transparent film, leading to a remarkable enhancement of the sensitivity, and the detection limits are 3 ng/ml by spectrophotometry and 5 ng/ml by visual colorimetry, respectively. Using spectrophotometer, a linear calibration curve is obtained over the concentration range of 0 to 50 ng/ml of Al. Further, the color system, consisting of red ([A1L₂]^–), yellow (H₂L), and blue violet (CV⁺), gave clear color changes suitable for visual determination of aluminum with an applicable range of 0 to above 3000 ng/ml. The four different color zones are khaki for 0–5 ng/ml, reddish-brown for 5–200 ng/ml, blue violet for 200 ng/ml-3g/ml, and colorless for more than 3g/ml. The proposed method has been successfully applied for the determination of aluminum in tap waters.     

Alkane Shape- and Size-Recognized Selective Vapor Sorption in “Channel-Like” Crystals Based on Thiacalixarene Assemblies

Alkanes composed of C−C and C−H show a low electric polarization, and therefore, there is only very weak interaction between alkanes and adsorbents. Thus, it is difficult to separate a specific alkane from a mixture of alkanes by adsorption. Here, two activated “channel-like” crystals generated from brominated thiacalix[4]arene propyl ethers, which adopt 1,3-alternate and partial cone conformations, recognize specific alkane vapors depending on alkane-shape and -size, sorting in three-type alkane guests such as linear, branched, and cyclic alkanes. Two activated crystals, which are prepared by removal of solvent upon heating under reduced pressure, incorporate branched and/or cyclic alkane vapors by a unique “gate-opening” mechanism via a crystal transformation in the process. Linear alkane vapors do not trigger gate opening and are not taken up by the activated crystals. The shape and size molecular-recognition properties of the activated crystals promises considerable usefulness for the separation of linear, branched, and cyclic alkanes.     

Resolution improvement in optical coherence tomography by optimal synthesis of light-emitting diodes

We present a new approach to improving the longitudinal resolution of optical coherence tomography by optimal synthesis of several LED's. The search for an optimal synthesis of several low-coherence sources involves solution of an inverse problem, and an optimization algorithm is introduced that is used to arrange the parameters of light sources to effectively reduce the width of the center peak and inhibit the sidelobes simultaneously. Good coincidence between the experimental result and theoretical expectation is found.     

Numerical study of free-piston shock tunnel performance

A free-piston shock tunnel (FPST) is one of the most useful ground testing facilities for hypervelocity flow research of re-entry vehicles and scramjet engines. For an efficient operation with tuned piston motion, the design of facility and the comprehension of the physical phenomena in a FPST, a numerical simulation which can properly predicts the flow with actual losses is required. But there are few successful numerical methods which can simulate its overall performance. In the present study, numerical method was developed by using the KRC shock capturing scheme and by modeling the flow losses in suitable forms for a quasi-1D numerical computation. The present numerical results were compared with the data obtained in two different facilities, T4 and T5. The applicability of the present numerical method as a design tool is discussed briefly.This article was processed using Springer-Verlag T_EX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society.     

Sesquarterpenes (C35 terpenes) biosynthesized via the cyclization of a linear C35 isoprenoid by a tetraprenyl-β-curcumene synthase and a tetraprenyl-β-curcumene cyclase: identification of a new terpene cyclase

In this study, mono- and pentacyclic C(35) terpenes from Bacillus subtilis were biosynthesized via the cyclization of C(35) isoprenoid using purified enzymes, including the first identified new terpene cyclase that shows no sequence homology to any of the known terpene cyclases. On the basis of these findings, we propose that these C(35) terpenes should be called the new family of "sesquarterpenes."     

Curvature tensors and covariant derivatives

Summary The problems considered here are of two types.(i) What are implications of vanishing k-th covariant derivatives of curvature tensors?(ii) Under what conditions on curvature tensors, does the k-th covariant derivative ∇^kT=0 for a tensor T mean ∇T=0? Entrato in Redazione il 16 Maggio 1972.