X-ray absorption near edge spectroscopy with a superconducting detector for nitrogen dopants in SiC.

Fluorescence-yield X-ray absorption fine structure (FY-XAFS) is extensively used for investigating atomic-scale local structures around specific elements in functional materials. However, conventional FY-XAFS instruments frequently cannot cover trace light elements, for example dopants in wide gap semiconductors, because of insufficient energy resolution of semiconductor X-ray detectors. Here we introduce a superconducting XAFS (SC-XAFS) apparatus to measure X-ray absorption near-edge structure (XANES) of n-type dopant N atoms (4 ×10(19) cm(-3)) implanted at 500°C into 4H-SiC substrates annealed subsequently. The XANES spectra and ab initio multiple scattering calculations indicate that the N atoms almost completely substitute for the C sites, associated with a possible existence of local CN regions, in the as-implanted state. This is a reason why hot implantation is necessary for dopant activation in ion implantation. The SC-XAFS apparatus may play an important role in improving doping processes for energy-saving wide-gap semiconductors and other functional materials.

Charge-state-derivation ion detection using a super-conducting nanostructure device for mass spectrometry.

Mass spectrometry (MS) is a method of analyzing ions based on their mass/charge (m/z) ratios. The m/z peak identification requires speculation on the ionic unit-charge states. This problem can be solved by using superconducting junction devices to measure the kinetic energies of single molecules. However, the kinetic energy measurement is followed by the dead time of 1-20 µs, which is fatally slow for modern high-resolution time-of-flight (TOF) analyzers. In this paper, we demonstrate that a superconducting nano-stripline detector (SSLD) composed of a 10-nm-thick and 800-nm-wide NbN strip realizes the charge-state derivation, and furthermore satisfies the ideal MS detector specifications such as a nano-second response, a short recovery time, a wide mass range, and no noise.

First synthesis of phenylazomethine dendrimer ligands and structural studies.

Novel dendritic polyphenylazomethines (DPAs), which consist of a pi-conjugated backbone, were synthesized up to the fourth generation by the convergent method via dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained dendrimers, DPA G1-4 (designated as GX, where X is the generation number), show high thermostability (Td(10%) 521 degrees C in DPA G4) and high solubility for the common solvents such as chloroform, THF, and DMSO unlike the conventional linear polyphenylazomethines, which have very low solubilities. The DPA G4 molecule was confirmed to have a spherelike structure by GPC measurement and a molecular model based on the crystal structure of DPA G2. Crystal data for DPA G2: monoclinic space group P2(1)/a, a = 25.352(4) A, b = 8.577(2) A, c = 16.151(2) A, beta = 106.25(1) degrees, V = 3371.6(10) A(3), Z = 2, D(calc) = 1.168 g/cm(3), mu(Cu Kalpha) = 0.536 cm(-1), final R = 0.089, and R(w) = 0.287. The molecular modeling reveals that a DPA G4 molecule has a spherelike structure, in which the height, width, and depth are 2.3, 2.9, and 2.5 nm, respectively. The TEM and AFM pictures show the DPA G4 molecules to have a spherelike structure (the diameter: 2.3 nm) and are regularly assembled on a plate by casting. The occupied area of one DPA G4 molecule in a monolayer on water was estimated by pi-A measurements to be 3.8-4.2 nm(2) (the calculated diameter 2.2-2.3 nm, which agreed with the TEM result). NMR studies (1H NMR at 130 degrees C and T(1) measurements) supported a conformational rigidity of DPA G4 in solution.

Novel phenylazomethine dendrimers: synthesis and structural properties

The novel dendrimers consisting of a pi-conjugated backbone, the dendritic polyphenylazomethines (DPAs), were synthesized by the convergent method via the dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained DPAs have a high solubility unlike the conventional linear polyphenylazomethines. NMR studies revealed the conformational rigidity of DPA G4. DPAs having many azomethine groups as the coordination site for metal ions are expected to be novel ligands.

Selective synthesis of novel cyclic phenylazomethine trimers

Novel cyclic phenylazomethine trimers (CPAs) were synthesized in a one-step dehydration of the 4-aminobenzophenone derivatives in the presence of TiCl(4) or p-toluenesulfonic acid (PTS). The CPAs were isolated in over 90% yield under nondilute conditions. When using TiCl(4) as the dehydration agent, the induction of bulky substituents at the alpha-position of the substrate enhanced the yields of the CPAs. On the other hand, PTS served as an effective catalyst for the synthesis of the phenyl-substituted CPA. This different reactivity between TiCl(4) and PTS depends on the dehydration mechanism being dominated by a kinetic process or thermodynamic one. The obtained CPAs were confirmed by NMR, UV-vis spectra, and MM2 calculation to have only a Z conformation and a nonconjugated structure compared to the linear oligophenylazomethines (OPAs) and the aniline-capped OPAs (OPA's).

Anti-proliferative effect of combined tumour necrosis factor-alpha and interferon-alpha on human pancreatic cancer in vitro and in vivo.

The anti-proliferative effects of tumour necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha), alone or in combination, on human pancreatic cancer cells lines (PANC-1, MIA PaCa-2 and BxPC-3) and human pancreatic cancer tumour (Exp-58), were investigated in vitro and in vivo. The anti-proliferative effect was determined using the dye uptake method and the subcutaneous tumour model. Combined TNF-alpha and IFN-alpha demonstrated marked synergistic and/or additive effects in comparison with their effects as single agents. These results suggest that combined cytokine therapy of TNF-alpha and IFN-alpha may make possible some improvement in the treatment of pancreatic carcinoma patients in the future.

In vitro and in vivo activities of SCE-2787, a new parenteral cephalosporin with a broad antibacterial spectrum.

SCE-2787, a new cephalosporin having a condensed azolium moiety in the 3 position and an aminothiadiazolyl group in the 7 beta side chain, was evaluated for its in vitro and in vivo activities in comparison with those of ceftazidime, flomoxef, cefpirome, and E1040. Against methicillin-susceptible strains of Staphylococcus aureus and Staphylococcus epidermidis, SCE-2787 was more active than ceftazidime and E1040 and was as active as flomoxef and cefpirome, with MICs for 90% of strains tested (MIC90s) being 1.56 micrograms/ml or less. SCE-2787 was also active against Pseudomonas aeruginosa, for which the MIC90 was 6.25 micrograms/ml, which was lower than that of cefpirome and comparable to that of ceftazidime. SCE-2787 was marginally active against methicillin-resistant strains of staphylococci and Enterococcus faecalis, although its MIC90s were the lowest among those of the antibiotics tested. The activities of SCE-2787 against Streptococcus species, most members of the family Enterobacteriaceae, and Haemophilus influenzae exceeded those of ceftazidime and flomoxef and were comparable to those of cefpirome. Furthermore, MIC90s of SCE-2787 were significantly lower than those of ceftazidime for ceftazidime-resistant isolates of Citrobacter freundii and Enterobacter cloacae. SCE-2787 was resistant to hydrolysis by various types of beta-lactamases, including the Bush group 1 beta-lactamases, and had low affinities for these enzymes, with Km or Ki values of greater than 100 microM. The in vitro activity of SCE-2787 was reflected in its efficacy in mouse protection tests. Thus, SCE-2787 appears to be a promising cephalosporin that should be further evaluated in clinical trials.

A case of superior lumbar hernia.

A case of a superior lumbar hernia in a 50 year old woman is described herein. She presented with a 7 x 8 cm soft, nontender, smooth-surfaced mass in the left flank, and barium meal with follow through showed herniation of the descending colon. At operation, a 6 x 5 cm defect was found in the transversalis fascia, which was repaired with mattress sutures to the transversalis fascia together with suturing of the external oblique to the latissimus dorsi. This article presents the above case and reviews the published literature relating to this subject.