Development of a robot assisted carotid blood flow measurement system

The ultrasound diagnosis of the carotid artery is one of the most common non-invasive methods to detect early stage heart and cerebrovascular diseases. However, the precision and repetitiveness of the probe positioning depend exclusively on the operator's skills and dexterity. For this purpose, we propose the development of a robot assisted system to enhance the accuracy and repetitiveness of the probe positioning to measure the wave intensity (WI) index. In this paper, the Waseda-Tokyo Women's Medical-Aloka Blood Flow Measurement Robot System No. 2 Refined (WTA-2R) is presented. The WTA-2R consists of a conventional ultrasound diagnosis system, a 6-DOFs parallel link slave manipulator, a 6-DOFs serial link passive arm, and a master device. Experiments were carried out to verify its effectiveness in terms of accuracy and required time to perform the task. From the experimental results, the positioning accuracy and reduction of required time were confirmed.     

Quantification of free ketene acetals and determination of cure kinetics of poly(ortho ester)s by a facile deuterium labeling method

A facile method was developed to quantify unreacted ketene acetals during polymerization of poly(ortho ester)s. The method was based on isotopic (deuterium) labeling of the unreacted ketene acetal groups arising from the diketene acetal monomer, 3,9-diethylidene-2,4,8,10-tetraoxaspiro[5,5]undecane (DETOSU). In deuterium oxide, free ketene acetals are hydrolyzed to an α-deuterated ester; ortho ester bonds are hydrolyzed to the nondeuterated analog. The relative abundance of the deuterated ester side chain can be quantified by gas chromatography-mass spectrometry (GC-MS). In the current method, aliquots of a diketene acetal/polyol(s) reaction mixture were dissolved (crosslinked polymers swollen) in methylene chloride and excess D₂O. The diketene acetal/polyol(s) reaction mixture was hydrolyzed under mildly acidic conditions to yield pentaerythritol dipropionate (PDP; hydrolysis product of DETOSU). PDP was extracted into an organic phase, silylated, and analyzed by GC-MS. Fragments corresponding to the C₂H₅C?O+ ion (57 a.m.u.) and C₂H₄DC?O+ ion (58 a. m. u.) were monitored and the quantity of free ketene acetal groups were calculated from the peak areas of the chromatograms. The precision of the method was ±0.1%. The accuracy, as compared to a parallel ¹H-NMR study, was within 5%. This method permits determination of the cure end-point of a poly(ortho ester) polymerization reaction to within ±0.25%. The curing kinetics agreed well with DSC branching/crosslinking measurements. © 1994 John Wiley & Sons, Inc.     

Quantitative analysis of deuterium in zircaloy using double-pulse laser-induced breakdown spectrometry (LIBS) and helium gas plasma without a sample chamber

A crucial safety measure to be strictly observed in the operation of heavy-water nuclear power plants is the mandatory regular inspection of the concentration of deuterium penetrated into the zircaloy fuel vessels. The existing standard method requires a tedious, destructive, and costly sample preparation process involving the removal of the remaining fuel in the vessel and melting away part of the zircaloy pipe. An alternative method of orthogonal dual-pulse laser-induced breakdown spectrometry (LIBS) is proposed by employing flowing atmospheric helium gas without the use of a sample chamber. The special setup of ps and ns laser systems, operated for the separate ablation of the sample target and the generation of helium gas plasma, respectively, with properly controlled relative timing, has succeeded in producing the desired sharp D I 656.10 nm emission line with effective suppression of the interfering H I 656.28 nm emission by operating the ps ablation laser at very low output energy of 26 mJ and 1 μs ahead of the helium plasma generation. Under this optimal experimental condition, a linear calibration line is attained with practically zero intercept and a 20 μg/g detection limit for D analysis of zircaloy sample while creating a crater only 10 μm in diameter. Therefore, this method promises its potential application for the practical, in situ, and virtually nondestructive quantitative microarea analysis of D, thereby supporting the more-efficient operation and maintenance of heavy-water nuclear power plants. Furthermore, it will also meet the anticipated needs of future nuclear fusion power plants, as well as other important fields of application in the foreseeable future.     

The salvage of aneurysmal fistulae utilizing a modified buttonhole cannulation technique and multiple cannulators

We describe the St Michael's Hospital (SMH) modified buttonhole (BH) cannulation technique as a method that offers a solution for fistulae with aneurysmal dilatation due to repetitive cannulation in a restricted area. This is a prospective cohort study of 14 chronic hemodialysis (HD) patients with problematic fistulae (marked aneurysmal formation and thinning of the overlying skin, bleeding during treatment, and prolonged hemostasis post-HD) because of repetitive, localized cannulation. Each patient was followed for 12 months. The protocol was as follows: creation of tunnel tracks by 1 to 3 experienced cannulators per patient, using sharp needles. After the tunnel tracks were established and cannulation was easily achieved with dull needles, additional cannulators were incorporated with the guidance of a mentor. Bleeding from cannulation sites during dialysis ceased within 2 weeks and skin damage resolved within 6 months in all patients. Hemostasis time postdialysis decreased from 24 to 15 min. Cannulation pain scores decreased significantly. Access flows and dynamic venous pressure measurements remained unchanged. No interventions were required to maintain access patency. In 2 cases, the aneurysms became much less evident. Complications included one episode of septic arthritis and one contact dermatitis. A third patient developed acute bacterial endocarditis 9 months following completion of her follow-up. The SMH modified BH cannulation technique can salvage problematic fistulae, prevent further damage, and induce healing of the skin in the areas of repetitive cannulation. This technique can be successfully achieved by multiple cannulators in a busy full-care HD unit.     

Use of the BioHole™ device for the creation of tunnel tracks for buttonhole cannulation of fistula for hemodialysis

Buttonhole cannulation is a method of cannulation of native arteriovenous fistulae traditionally practiced by self‐cannulators. At St Michael's Hospital, this method has been modified to allow its use in problematic fistulae by multiple cannulators. In a busy dialysis unit, the need for a few specific cannulators to establish the tunnel tracks in combination with the variable dialysis schedules creates logistical challenges. A new method of creating tunnel tracks with the use of the BioHole^? device was evaluated. Buttonhole tracks were created in 12 patients using a peg of polycarbonated material with a holder (BioHole^? kit). The peg was inserted into the path left by the hemodialysis sharp needle following the index cannulation. Four of the 12 patients had an alternate access. Buttonhole tracks were successfully created in all the patients, albeit in 2 patients, the initial attempt to establish buttonhole tracks was aborted due to complications and the procedure was rescheduled. Compared with the modified buttonhole technique, pain on cannulation following track creation was significantly less in the BioHole^? group (P<0.001). Ease of cannulation was significantly improved in the BioHole^? group (P<0.05) when compared with that in thrice‐weekly patients using the modified buttonhole technique. Hemostasis postdialysis did not differ between the study groups. The use of the BioHole^? device is effective in the creation of tunnel tracks for buttonhole cannulation, is associated with less pain, and simplifies the logistics of arranging patient and nurses' schedules.     

A Possible Magnetic Phase with Scalar Chirality in Solid 3He Layers

We study quantum effects in a system of S = 1/2 spins with two–, three and four–spin exchange interactions on the triangular lattice, a possible model of the nuclear magnetism of solid ³ He layers. The ground state phases found in our previous work are studied by using the linear spin–wave theory. The uuud state shows a very flat spin–wave dispersion, which suggests that this state, though locally stable, will not survive non–linear quantum effects. The tetrahedral state, which has long–range order of a scalar chirality, is found to be stable against spin wave fluctuations. The ground state energies of different phases are compared. Results of numerical analysis of finite size clusters are also presented.     

Evaluation of serum KL-6 levels in summer-type hypersensitivity pneumonitis

A high level of serum KL-6 is a known feature of active pulmonary fibrosis. Some researchers have suggested that KL-6 is produced and secreted by type II pneumocytes. The present study evaluated serum KL-6 levels in patients with summer-type hypersensitivity pneumonitis (summer-type HP) (n = 6, 7 episodes), Mycoplasma pneumoniae pneumonia (n = 16), Chlamydia psittaci pneumonia (n = 3), Chlamydia pneumoniae pneumonia (n = 9), and bacterial pneumonia (n = 12). In addition, transbronchial lung biopsy (TBLB) specimens were examined pathologically in order to identify the site of production and secretion of KL-6. In patients with summer-type HP, the serum KL-6 levels exceeded 500 U/ml (2.996 +/- 2.016 U/ml), but was below 500 U/ml (302 +/- 126 U/ml, p < 0.001) in the patients with other infectious pneumonias, with the exception of two. One of these two patients with a high serum KL-6 level had adult respiratory distress syndrome due to Mycoplasma pneumoniae. The other had organizing pneumonia due to Chlamydia pneumoniae. TBLB specimens showed proliferative type II pneumocytes in all summer-type HP cases. We believe that the high serum KL-6 levels were produced by type II pneumocytes, and may provide a useful indicating serum marker for HP. Although serum LDH, serum CRP and PaO2 are known as monitoring markers in summer-type HP, our findings demonstrated no manifest correlations among these markers. However, serum KL-6 levels showed a strong positive correlation with serum LDH levels and an inverse correlation with serum CRP levels. These results suggest that serum KL-6 may be a better marker of the degree of disease activity than serum LDH, CRP, or PaO2 in summer-type HP.     

Antiatherogenic effects of the antioxidant BO-653 in three different animal models

Antioxidants have been proposed to have antiatherogenic potential by their inhibition of low density lipoprotein (LDL) oxidation. Here, we report an antioxidant, BO-653 (2,3-dihydro-5-hydroxy-2, 2-dipentyl-4,6-di-tert-butylbenzofuran), designed to exhibit antioxidative potency comparable to that of alpha-tocopherol, but yet possess a high degree of lipophilicity comparable to that of probucol. BO-653 exhibits a high affinity for LDL and is well distributed in aortic vessels in vivo. In atherosclerosis models of rabbits and mice, BO-653 has been shown to be able to suppress the formation of atherosclerotic lesions without untoward side effects. Specifically, there was no reduction of high density lipoprotein levels. This antioxidant provides additional evidence in support of the oxidized-LDL hypothesis, and itself is a promising candidate antioxidant for clinical use.