Biomedical subjects

Norio Nakata

Publications and source records attributed to Norio Nakata.

11 recordsLinked to original sources

PubMed2007

Coordination chemistry of a kinetically stabilized germabenzene: syntheses and properties of stable eta6-germabenzene complexes coordinated to transition metals.

The first stable eta6-germabenzene complexes, that is, [M(CO)3(eta6-C5H5GeTbt)] {M=Cr (2), Mo (3), and W (4); Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl}, have been synthesized by ligand-exchange reactions between [M(CO)3(CH3CN)3] (M=Cr, Mo, and W) and the kinetically stabilized germabenzene 1 and characterized by 1H and 13C NMR, IR, and UV/Vis spectroscopy. In the 1H and 13C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1. X-ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO)3 group (M=Cr, W) in an eta6 fashion. The formation of complexes 2-4 from germabenzene 1 should be noted as the application of germaaromatics as 6pi-electron ligands toward complexation with Group 6 metals. On the other hand, treatment of 1 with [{RuCp*Cl}4] (Cp*=C5Me5) in THF afforded a novel eta5-germacyclohexadienido complex of ruthenium-[RuCp*{eta5-C5H5GeTbt(Cl)}] (9)-instead of the expected eta6-germabenzene-ruthenium cationic complex [RuCp*{eta6-C5H5GeTbt}]Cl (10). Crystallographic structural analysis of 9 showed that the five carbon atoms of the germacyclohexadienido ligand of 9 were coordinated to the Ru center in an eta5 fashion.

Journal Article↗

PubMed2006

A stable Schrock-type hafnium-silylene complex.

The first stable hafnium-silylene complex, (eta-C5H4Et)2(PMe3)Hf=Si(SiMetBu2)2 (6) was obtained in the form of the phosphine adduct as red crystals by the coupling reaction of 1,1-dilithiosilane (1) with 0.9 equiv of (eta-C5H4Et)2HfCl2 in dry toluene at -50 degrees C, followed by treatment with an excess of PMe3 at -50 degrees C. In the 29Si NMR spectrum of 6, the signal from the silylene ligand is shifted greatly downfield at 295.4 ppm, with a JSiP coupling constant of 15.0 Hz. X-ray crystallographic analysis of 6 revealed that the Si-Hf bond length (2.6515(9) A) is about 5% shorter than typical Si-Hf single bonds, obviously indicating the double-bond character between the silicon and hafnium atoms. The compound 6 was found to be a Schrock-type silylene complex, a conclusion that was supported by the natural population analysis (NPA) charge distribution for the model complex, (eta-C5H4Et)2(PMe3)Hf=Si(SiMe3)2 (8), showing a negative charge on the silicon atom (-0.34).

Journal Article↗

PubMed2006

A stable silaborene: synthesis and characterization.

A stable silicon-boron doubly bonded compound, silaborene (2), was synthesized by the reaction of 1,1-dilithiosilane (1) with dichloro(2,2,6,6-tetramethylpiperidino)borane in toluene. The X-ray crystallographic analysis of 2 revealed that the >Si=B-N< framework is almost linear (176.87(13) degrees ) with an Si-B bond length of 1.8379(17) A, which is about 10% shorter than typical Si-B single bonds. The silaborene 2 reacted with lithium trimethylsilylacetylide at 60 degrees C in DME to give the corresponding silaborenide (4-.[Li(dme)3]+), whose reddish-orange crystals were isolated as the solvent separated ion pair. The X-ray analysis of 4-.[Li(dme)3]+ showed that the Si-B bond length (1.933(3) A) is longer than that of 2, but still shorter than typical Si-B single bonds. These structural features indicate that 4- has double bond character involving the >Si=B<- resonance structure.

Journal Article↗

PubMed2006

Surgical navigation display system using volume rendering of intraoperatively scanned CT images.

As operative procedures become more complicated, simply increasing the number of devices will not facilitate such operations. It is necessary to consider the ergonomics of the operating environment, especially with regard to the provision of navigation data, the prevention of technical difficulties, and the comfort of the operating room staff. We have designed and created a data-fusion interface that enables volumetric Maximum Intensity Projection (MIP) image navigation using intra-operative mobile 3D-CT data in the OR. The 3D volumetric data reflecting a patient's inner structure is directly displayed on the monitor through video images of the surgical field using a 3D optical tracking system, a ceiling-mounted articulating monitor, and a small-size video camera mounted at the back of the monitor. The system performance and accuracy was validated experimentally. This system provides a novel interface for a surgeon with volume rendering of intra-operatively scanned CT images, as opposed to preoperative images.

Computer Graphics↗

PubMed2005

Data-fusion display system with volume rendering of intraoperatively scanned CT images.

In this study we have designed and created a data-fusion display that has enabled volumetric MIP image navigation using intraoperative C-arm CT data in the operating room. The 3D volumetric data reflecting a patient's inner structure is directly displayed on the monitor through video images of the surgical field using a 3D optical tracking system, a ceiling-mounted articulating monitor, and a small size video camera mounted at the back of the monitor. The system performance was validated in an experiment carried out in the operating room.

Computer Graphics↗

PubMed2005

Development of a 3D visualization system for surgical field deformation with geometric pattern projection.

Intra-operative navigation in which the target position is provided to assist an intuitive understanding of the surgical field has been studied and applied in many clinical areas. Position measurement of a surgical field is usually performed with a magnetic sensor, a marker type optical position sensor. For navigation of hard tissue, the measurement of several markers dispersedly located on the surface is enough to detect the position of an object that can be assumed as a rigid body. However, for the navigation of soft tissue such as skin and liver, a sensor that can measure the deformation of the object surface time-sequentially would be essential. We have developed a 3D visualization system for surgical field deformation with geometric pattern projection. In an animal experiment, the registration of preoperative 3D organ model could be done with the time-sequentially updated surface deformation data. In the video image of surgical field, the inner structure model of organ could be superimposed successfully.

Elasticity↗

PubMed2005

[Clinical usefulness of B-flow imaging in the diagnosis of superficial soft tissue tumors].

B-flow imaging is a recently developed ultrasound technique that extends the B-mode imaging quality of blood flow, including high-frame-rate and high-spatial-resolution imaging. The purpose of the present study was to clarify the usefulness of B-flow for evaluation of the hemodynamics of superficial soft tissue tumors. All 33 cases of superficial soft tissue tumors were examined by both B-flow and Color/Power Doppler methods on the same plane. The B-flow images that were obtained were evaluated by comparison with corresponding Color/Power Doppler images. The following four items were compared and evaluated: (1) sensitivity to the detection of tumor vessels; (2) quality of background B-mode imaging; (3) frame rate; and (4) spatial resolution of tumor vessels. B-flow was somewhat inferior to Color/Power Doppler imaging in sensitivity to the detection of tumor vessels. B-flow was clearly inferior in the quality of background B-mode imaging. B-flow provided high-frame-rate imaging. The diameter of tumor vessels on B-flow imaging was clearly thinner than that on Color/Power Doppler images and appeared to indicate the true diameter of tumor vessels. By providing high-frame-rate imaging and high spatial resolution, B-flow makes it possible to clarify the precise vascular structure.

Blood Flow Velocity↗

PubMed2004

1,3-Disila-2-gallata- and -indataallenic Anions [>SiMSi<]-.Li+ (M = Ga, In): compounds featuring double bonds between elements of groups 13 and 14.

The first compounds containing Si=Ga or Si=In double bonds, 1,3-disila-2-gallata- (2-) and -indataallenic anions (3-), were obtained in the form of lithium salts as dark red crystals by the reaction of bis(di-tert-butylmethylsilyl)dilithiosilane 1 with GaCl3 or InCl3. X-ray crystallographic analysis of 2-.[Li(thf)4]+ and 3-.[Li(thf)4]+ showed that the >SiMSi< frameworks (M = Ga, In) are not linear and the two Si=M bond lengths are about 9% shorter than typical Si-M single bonds. In the 29Si NMR spectra, the signals of the terminal Si atoms in 2- and 3- are greatly shifted upfield (2-: -79.9; 3-: -77.6 ppm). The NPA charge distribution for the model compound, [(Me3Si)2SiGaSi(SiMe3)2]- (4-) showed a large part of the negative charge localizing on the two terminal silicon atoms (-0.736 and -0.729). In addition, 2-.[Li(thf)4]+ reacted with MeI to give the corresponding iodogallane 5 nearly quantitatively. This result confirms that the allenic [>SiMSi<]- fragments are highly polarized.

Journal Article↗

PubMed2002

Synthesis and properties of the first stable germabenzene.

The first stable germabenzene (1a) bearing an efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, was successfully synthesized by the reaction of the corresponding chlorogermane (4) with lithium diisopropylamide in THF. The molecular structure and aromaticity of 1a were discussed on the basis of its NMR, UV-vis, and Raman spectra, X-ray crystallographic analysis, and theoretical calculations. All (1)H and (13)C NMR chemical shifts of the germabenzene ring of 1a were in good agreement with those calculated. UV-vis and Raman spectra of 1a showed patterns similar to those of benzene, suggesting the structural similarity between germabenzene and benzene. X-ray crystallographic analysis of 1a revealed that the germabenzene ring was almost planar, indicating the delocalization of pi-electrons. Theoretical calculations (NICS(1) and ASE(isom)) also indicated the ring current effects and aromatic stabilization of the germabenzene. While germabenzene 1a reacted as a Ge[bond]C double-bond compound (germene) with mesitonitrile oxide and 2,3-dimethyl-1,3-butadiene, 1a also reacted as a 1-germabuta-1,3-diene with C[bond]C double- and triple-bond compounds. Furthermore, 1a reacted with water and MeOH to give both 1, 2- and 1, 4-adducts.

Journal Article↗

PubMedDate not supplied

Wireless local area networking for linking a PC reporting system and PACS: clinical feasibility in emergency reporting.

Although local area networks (LANs) are commonplace in hospital-based radiology departments today, wireless LANs are still relatively unknown and untried. A linked wireless reporting system was developed to improve work throughput and efficiency. It allows radiologists, physicians, and technologists to review current radiology reports and images and instantly compare them with reports and images from previous examinations. This reporting system also facilitates creation of teaching files quickly, easily, and accurately. It consists of a Digital Imaging and Communications in Medicine 3.0-based picture archiving and communication system (PACS), a diagnostic report server, and portable laptop computers. The PACS interfaces with magnetic resonance imagers, computed tomographic scanners, and computed radiography equipment. The same kind of functionality is achievable with a wireless LAN as with a wired LAN, with comparable bandwidth but with less cabling infrastructure required. This wireless system is presently incorporated into the operations of the emergency and radiology departments, with future plans calling for applications in operating rooms, outpatient departments, all hospital wards, and intensive care units. No major problems have been encountered with the system, which is in constant use and appears to be quite successful.

Emergency Service, Hospital↗

PubMedDate not supplied

Informatics in Radiology (infoRAD): mobile wireless DICOM server system and PDA with high-resolution display: feasibility of group work for radiologists.

A novel mobile system has been developed for use by radiologists in managing Digital Imaging and Communications in Medicine (DICOM) image data. The system consists of a mobile DICOM server (MDS) and personal digital assistants (PDAs), including a Linux PDA with a video graphics array (VGA) display (307,200 pixels, 3.7 inches). The MDS weighs 410 g, has a 60-GB hard disk drive and a built-in wireless local area network (LAN) access point, and supports a DICOM server (Central Test Node). The Linux-based MDS can be accessed with personal computers (PCs) and PDAs by means of a wireless or wired LAN, and client-server communications can be established at any time. DICOM images can be displayed by using any PDA or PC by means of a Web browser. Simultaneous access to the MDS is possible for multiple authenticated users. With most PDAs, image compression is necessary for complete display of DICOM images; however, the VGA screen can display a 512 x 512-pixel DICOM image almost in its entirety. This wireless system allows efficient management of heavy loads of lossless DICOM image data and will be useful for collaborative work by radiologists in education, conferences, and research.

Computers, Handheld↗