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In secondary ion mass spectrometry (SIMS), the detection of large organic molecules is accomplished using cluster ion bombardment. Ion formation often proceeds via cationization, through the attachment of (alkali) metal ions to the molecule. To study this process, the emission of secondary ions sputtered from polyethylene glycol (PEG) samples with molecular weights (MW) of 1000–10000 was examined. They were mixed with alkali-metal trifluoroacetic acid (X-TFA, where X = Li, Na, K, or Cs) in a wide range of concentrations to investigate the efficiency of cationization for 10 keV Ar2000+cluster irradiation. Typically, cationized molecular ions [M + X]+(with repeat units nof up to ∼250, corresponding roughly to m/z11000) and some characteristic fragment species were observed in the mass spectra. For all alkali cations, the oligomer intensities increase strongly with the molecular composition ratios X-TFA/PEG in the samples, and values of 5–10 seem to be optimal. With increasing molecular weight, the intensity of oligomer ions relative to the total number of ions decreases; as the latter remains rather constant, this implies that more fragment species are formed. The ion yields (detected ions per primary ions) of cationized [M + Na]+oligomers sputtered from a PEG decrease very strongly with their size n: from 5.2 × 10–6at n= 21 (MW ∼ 1000) to 4.5 × 10–10at n∼ 245 (MW ∼ 11000). By contrast, the total yields Ytot+show only a small variation for these different specimens, from 1.3 × 10–5to 3.7 × 10–5.

A two-dimensional nanocarbon, graphene, has attracted substantial interest due to its excellent properties. The reduction of graphene oxide (GO) has been investigated for the mass production of graphene used in practical applications. Different reduction processes produce different properties in graphene, affecting the performance of the final materials or devices. Therefore, an understanding of the mechanisms of GO reduction is important for controlling the properties of functional two-dimensional systems. Here, we determined the average structure of reduced GO prepared viaheating and photoexcitation and clearly distinguished their reduction mechanisms using ultrafast time-resolved electron diffraction, time-resolved infrared vibrational spectroscopy, and time-dependent density functional theory calculations. The oxygen atoms of epoxy groups are selectively removed from the basal plane of GO by photoexcitation (photon mode), in stark contrast to the behavior observed for the thermal reduction of hydroxyl and epoxy groups (thermal mode). The difference originates from the selective excitation of epoxy bonds viaan electronic transition due to their antibonding character. This work will enable the preparation of the optimum GO for the intended applications and expands the application scope of two-dimensional systems.

The reactive gas cluster injection process is an etching method that uses a neutral cluster beam without plasma. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from the plasma. The characteristics of an etching by ClF3–Ar gas cluster injection were investigated at various target distances, pattern widths, and sample temperatures. As a result, the relationship between the etching conditions and the aspect ratio was clarified, and an equation that can predict the maximum limit of the aspect ratio was derived from the ClF3flux and pattern widths. Then high aspect etching with an aspect ratio exceeding 20 is realized. And also, the 3D lever structure of 6 layers can be fabricated by double-angled etching with neutral cluster injection at the condition for high aspect etching.

The importance of imaging mass spectrometry MS for visualizing the spatial distribution of molecular species in biological tissues and cells is growing. We have developed a new system for imaging MS using MeV ion beams, termed MeVsecondary ion mass spectrometry MeVSIMS here, and demonstrated more than 1000fold increase in molecular ion yield from a peptide sample 1154 Da, compared to keV ion irradiation. This significant enhancement of the molecular ion yield is attributed to electronic excitation induced in the nearsurface region by the impact of high energy ions. In addition, the secondary ion efficiency for biologically important compounds >1 kDa increased to more than 1010cm−2, demonstrating that the current technique could, in principle, achieve micrometer lateral resolution. In addition to MeVSIMS, peptide compounds were also analyzed with clusterSIMS and the results indicated that in the former method the molecular ion yields increased substantially compared to the latter. To assess the capability of MeVSIMS to acquire heavyion images, we have prepared a micropatterned peptide surface and successfully obtained mass spectrometric imaging of the deprotonated peptides mz1153 without any matrix enhancement. The results obtained in this study indicate that the MeVSIMS technique can be a powerful tool for highresolution imaging in the mass range from 100 to over 1000 Da. Copyright © 2008 John Wiley & Sons, Ltd.

We performed myocardial revascularization with bilateral internal mammary arteries in eight children for coronary artery complications consequent to Kawasaki disease. Subjects included seven boys and one girl, ranging in age from 3 to 13 years (mean age, 8.3 ± 3.4 years). The body surface area ranged from 0.65 to 1.65 m2(average, 1.08 ± 0.35 m2). Three patients had a previous myocardial infarction. The right internal mammary artery was anastomosed to the right coronary artery and the left internal mammary artery was sutured to the left anterior descending artery in all patients. The patients received an average of 2.4 grafts. Magnifying loupes of 3.5× were used for anastomosis with 8-0 monofilament polypropylene sutures. Subjects were followed up from 12 to 38 months (23 ± 10.8 months) after operation. All were doing well with no recurrence of angina, and body development was normal, including the sternum and thorax according to chest x-ray films and computed tomography of the chest. Patency of the bilateral internal mammary arteries was 100% in the early (within 1 month) postoperative period and remained so in the late (over 1 year) postoperative period. Anastomotic junctions between the internal mammary artery and the coronary artery developed well angiographically in the late postoperative period. The internal mammary artery is the graft of choice for pediatric myocardial revascularization because of its excellent long-term patency and growth potential. Bilateral internal mammary arteries should be used whenever indicated, and the use of bilateral internal mammary arteries did not adversely influence chest wall development in the children.

Between December 1981 and June 1987, 71 patients underwent aortic valve replacement with a Bicer monostrut tilting disc prosthesis. Clinical results and in vivo function of the artificial valve were assessed. The average age of the 71 patients at the time of operation was 51.3 ± 11.5 years. The hospital mortality rate was 2.8% (two patients) and there were no further deaths during a mean (±SD) follow-up period of 2.4 ± 1.6 years (range 1 month to 5.5 years) after surgery. There was also no occurrence of thromboembolism or valve dysfunction.

We used quantitative angiography to determine the postoperative diameter of the internal thoracic artery graft at the point close to the anastomosed site in 147 patients who received the graft for the left anterior descending coronary artery. We performed generalized multiple linear regression analysis (Type I quantification method) to assess the effects of the following factors on the internal thoracic artery graft diameter: age, gender, time of angiography, laterality of the internal thoracic artery used, presence of an undivided major side branch of the internal thoracic artery, presence of a saphenous vein graft having blood flow competition with an internal thoracic artery graft, presence of distal stenosis of the recipient left anterior descending coronary artery, severity of postoperative left anterior descending coronary artery stenosis, and presence of coronary risk factors. The standardized category scores for 25 % left anterior descending coronary artery stenosis, 50 % left anterior descending coronary artery stenosis, and presence of a saphenous vein graft having blood flow competition with an internal thoracic artery graft were –1.418, –0.767 and –0.622, respectively. Thus, the internal thoracic artery diameter was smaller in patients with well-preserved flow of the recipient coronary artery. The internal thoracic artery diameter had a particularly strong correlation with the degree of left anterior descending coronary artery stenosis (partial correlation coefficient: 0.670). The other factors seemed to have little or no correlation with the postoperative internal thoracic artery diameter. With the criterion that the internal thoracic artery diameter below 1.0 mm represents the “string sign” of internal thoracic artery graft, this phenomenon was observed in nine patients (6.1 %). In all of these patients, left anterior descending coronary artery flow was well-preserved, and no ischemia was disclosed in the left anterior descending coronary artery-perfused area. These results indicate that internal thoracic artery grafts have flow adaptability responding to the flow demand of the recipient coronary artery and that the string sign of internal thoracic artery grafts is mainly an outcome of its physiologic characteristics.

SummaryA 28-year-old woman with short stature was found to have bilateral gonadoblastoma in the dysgenetic ovaries. Chromosome banding analysis of her cultured blood cells and skin fibroblasts revealed a terminal deletion of the long arm of the X chromosome, 46,X,del(X)(q21), as the sole karyotypic anomaly. None of the Xq- patients so far reported were associated with gonadoblastoma.

We characterized the thickness and surface damage layer of poly(methyl metacrylate) (PMMA) organic films irradiated with Ar cluster or monomer ion beam using ellipsometry. A heavily damaged layer was detected on the surface of the PMMA film irradiated with Ar monomer ion beam; more than 2--3 nm of the surface were completely metamorphosed into a carbon-like layer and damage had accumulated with irradiation. On the other hand, no significant damage was detected on PMMA films irradiated with Ar cluster ion beams. These results corresponded with measurements of the irradiated surface by X-ray photoelectron spectroscopy (XPS). The sputtering depth from PMMA film irradiated with Ar cluster/monomer ion beams can also be measured using the ellipsometry method at nanometer-order resolution. The optical method of ellipsometry may be a desirable tool for sputtering yield measurement and surface damage layer estimation for organic films.

Reactive gas cluster injection is an etching method that uses a neutral cluster beam without ions. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from plasma. ClF3-Ar gas cluster injection was performed using a nozzle placed at various angles in the range of 0-78deg from the normal to the sample. The Si substrate was anisotropically etched in the direction of the cluster beam, although the incident angle of the cluster beam was oblique. Oblique holes of 100 nm diameter and oblique square pillars of 3 um width were fabricated with a high aspect ratio by angled cluster injection. It is expected that this process will create unprecedented structures for use in micro-electromechanical systems (MEMSs) or photonic crystals.

A reactive gas cluster injection system with a scanning function was developed in order to increase the processing area. High-precision anisotropic etching with an aspect ratio of 7 was achieved for ClF3 cluster etching without scanning. However, with scanning, the aspect ratio for etching decreased to 1.5 because the side walls were etched by the gas retained in the trench. By reducing the source gas pressure, increasing the target distance, and mixing He in the source gas, anisotropic etching with an aspect ratio of about 6.3 was achieved with this apparatus.

Hexafluoropropene oxide reacts smoothly with morpholine enamines from ketones and aldehydes at 0 °C to room temperature in anhydrous THF to give pentafluorinated 1,3-diketones in good yields. The keto-enol equilibrium in the products is generally in favor of their enol form.

Recent developments in cluster ion beams for secondary ion mass spectrometry (SIMS) have enabled the realization of molecular depth profiling and mass imaging of organic and biological materials. Massive Ar cluster beams present reduced surface damage and fragmented ion generation and are suitable as primary beams for SIMS. We recently obtained a finely focused massive 1.2-µm-diameter cluster ion beam and combined it with an orthogonal acceleration time-of-flight mass spectrometer. A mesh pattern of a phospholipid thin film was clearly reproduced in the mass images of molecular ions with a measurement time of 100 s.

The characteristics of Si etching using nonionic cluster beams with highly reactive chlorine-trifluoride (ClF3) gas were examined. An etching rate of 40 µm/min or higher was obtained even at room temperature when a ClF3molecular cluster was formed and irradiated on a single-crystal Si substrate in high vacuum. The etching selectivity of Si with respect to a photoresist and SiO2was at least 1:1000. We also succeeded in highly anisotropic etching with an aspect ratio of 10 or higher. Moreover, this etching method has a great advantage of low damage, compared with the conventional plasma process.

We have fabricated carbon nanotubes (CNTs) using a catalyzed growth technique that we call the carbon transmission method (CTM). We could control independently functions for carbon source gas supply and CNT growth by using a foil barrier (Ag) penetrated by pure Fe fibers. CNTs grew on one end of the Fe fibers, formed from diffused carbon that originates in carbon source gas at the other end of the fibers. Long CNTs with length over 100 µm were obtained on the end of the Fe fibers in the carbon transmitted side.