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Patient-derived xenograft (PDX) models have been recognized as being more suitable for predicting therapeutic efficacy than cell-culture models. However, there are several limitations in applying PDX models in preclinical studies, including their availability&mdash, especially for cancers such as gastric cancer&mdash, that are not frequently encountered in Western countries. In addition, the differences in morphology between primary, PDX, and tumor cell line-derived xenograft (CDX) models have not been well established. In this study, we aimed to establish a series of gastric cancer PDXs and cell-lines from a relatively large number of gastric cancer patients. We also investigated the clinicopathological factors associated with the establishment of PDX and CDX models, and compared the histology between the primary tumor, PDX, and CDX that originated from the same patient. We engrafted 232 gastric cancer tissues into immune-deficient mice subcutaneously and successfully established 35 gastric cancer PDX models (15.1% success rate). Differentiated type adenocarcinomas (DAs, 19.4%) were more effectively established than poorly differentiated type adenocarcinomas (PDAs, 10.8%). For establishing CDXs, the success rate was less influenced by histological differentiation grade (DA vs. PDA, 12.1% vs. 9.8%). In addition, concordance of histological differentiation grade between primary tumors and PDXs was significant (p &lt, 0.01), while concordance between primary tumors and CDXs was not. Among clinicopathological factors investigated, pathological nodal metastasis status (pN) was significantly associated with the success rate of PDX establishment. Although establishing cell lines from ascites fluid was more efficient (41.2%, 7/17) than resected tissues, it should be noted that all CDXs from ascites fluid had the PDA phenotype. In conclusion, we established 35 PDX and 32 CDX models from 249 gastric cancer patients, among them, 21 PDX/CDX models were established from the same patients. Our findings may provide helpful insights for establishing PDX and CDX models not only from gastric but from other cancer types, as well as select preclinical models for developing new therapeutics.

Lead-free silver nanoparticle pastes have been tested as a replacement for high temperature lead-rich solders used in electronic manufacturing. The pastes contain a small amount of solvent, and primarily consist of submicron-silver powder and passivated silver nanoparticles. The nanoparticles were synthesized from Ag2CO3 and a long-chain alcohol by a method that produced a passivating layer consisting almost exclusively of the carboxylate of the reactant alcohol. The pastes were used to connect a silicon diode chip to copper bases without applied pressure when sintered at 350°C under nitrogen. Diode packages made with sintered silver interconnects had electrical and thermal properties equal to those with lead-soldered interconnects, even after 3000 thermal cycles between −55°C and +150°C. The mechanical strength was half that of lead-rich solder joints, but still strong enough for practical use.

We propose a lead-free silver paste as a replacement for a high-temperature lead-rich solder used for electronics. The pastes tested here contain a small amount of solvent, but primarily consist of silver powder and alkoxide-passivated silver nanoparticles that undergo nanosintering when heated. The pastes were used to connect silicon diode chips to copper bases at 350°C in nitrogen ambient without external pressure. The resulting diode packages had electrical and thermal properties about equal to those with lead-solder joints. The mechanical strengths also were comparable to the lead joint. These properties make this nanosilver paste the first viable lead-free alternative to a lead solder.

We recently established a mouse model of peritoneal dissemination of human gastric carcinoma, including the formation of ascites, by orthotopic transplantation of cultured gastric carcinoma cells. To clarify the processes of expansion of the tumors in this model, nude mice were sacrificed and autopsied at different points of time after the orthotopic transplantation of the cancer cells for macroscopic and histopathologic examination of the tumors. The cancer cells grew actively in the gastric submucosa and invaded the deeper layers to reach the serosal plane. The tumor cells then underwent exfoliation and became free followed by the formation of metastatic lesions initially in the greater omentum and subsequent colonization and proliferation of the tumors on the peritoneum. Although this model allowed the detection of even minute metastases, it was not satisfactory from the viewpoint of quantitative and objective evaluation. To resolve these problems, we introduced a luciferase gene into this tumor cell line with a high metastasizing potential and carried out in vivo photon counting analysis. This photon counting technique was found to allow objective and quantitative evaluation of the progression of peritoneal dissemination on a real-time basis. This animal metastatic model is useful for monitoring the responses of tumors to anticancer agents. (Cancer Res 2006; 66(15): 7532-9)

The number of published studies on peritoneal dissemination of scirrhous gastric carcinoma is very small as a result of the unavailability of highly reproducible animal models. Orthotopic implantation of HSC-44PE and HSC-58 (scirrhous gastric carcinoma-derived cell lines) cells into nude mice led to dissemination of the tumor cells to the greater omentum, mesenterium, peritoneum and so on, and caused ascites in a small number of animals. Cycles of isolation of the ascitic tumor cells and orthotopic inoculation of these cells were repeated in turn to animals. This was to isolate highly metastatic cell lines with a strong capability of inducing the formation of ascites (44As3 from HSC-44PE; 58As1 and 58As9 from HSC-58). All three cell lines induced tumor formation at the site of orthotopic injection, and caused fatal cancerous peritonitis and bloody ascites in 90-100% of the animals approximately 3-5 weeks after the inoculation. When the parent cells were implanted, the animals became moribund in approximately 12-18 weeks, however, none of the animals developed ascites. Complementary DNA microarray and immunohistochemical analyses revealed differences in the expression levels of genes coding for the matrix proteinase, cell adhesion, motility, angiogenesis and proliferation between the highly metastatic- and parent-cell lines. The usefulness of this model for the evaluation of drugs was assessed by analyzing the stability of the metastatic potential of the cells and the reproducibility. Animals intravenously treated with CPT-11 and GEM showed suppressed tumor growth and significantly prolonged survival. The metastatic cell lines and the in vivo model established in the present study are expected to serve as a model of cancerous peritonitis developing from primary lesions, and as a useful means of clarifying the pathophysiology of peritoneal dissemination of scirrhous gastric carcinoma and the development of drugs for its treatment.

We investigate excitonic transitions and exciton–phonon interactions in disk-shaped microcrystallites of layered BiI 3 in CdI 2 matrices. We have observed the optical spectra and analyze the result...

We decomposed a silver-fatty acid complex at 250 °C in a nitrogen atmosphere to make stable, mono-disperse silver nanoparticles. The size distribution was measured using high-resolution transmission electron microscopy (HRTEM); the mean particle diameter was 4.7 nm and the standard deviation was 0.6 nm. This size distribution was verified by the measured surface-plasmon absorption spectrum. Their X-ray diffraction pattern showed that they were metallic silver. Then we examined their internal structure using HRTEM. The particles cross-sectional shapes were usually circular except some were hexagons or pentagons. According to the HRTEM image, most particles were multiple twins; 18% were simple twins and 2% were single crystals. Use of thermogravimetry and differential thermal analysis showed that their surface was coated by fatty acid. This coating stabilized the nanoparticles thus preventing their aggregation even after repeatedly dissolving them in solvent and evaporating. However, the coating was easily removed by baking at 210 °C in one atmosphere of air.

Raman scattering from BiI 3 and SbI 3 crystals has been studied at atmospheric and hydrostatic pressures up to 2 GPa. From the polarization characteristics, mode assignments were made for both crystals. The Raman shifts monotonically increased with pressure for all modes in BiI 3 . Although both crystals belong to the same space symmetry group, the pressure coefficients in SbI 3 were significantly different from those in BiI 3 . For a few modes, the coefficients gradually changed near P 1 = (0.30 ± 0.1) GPa, some of which were negative; also, near P 2 = (0.9 ± 0.1) GPa, the pressure coefficients of all modes changed. Above P 2 , all modes in SbI 3 had positive pressure coefficients as they have in BiI 3 . Furthermore, deformation-type stacking faults appear in SbI 3 only above P 2 , although it is known that these faults can form at all pressures in BiI 3 . By comparing this unusual behavior of the Raman lines in SbI 3 around P 2 with the results in BiI 3 and comparing the two lattice structures, we suggest that the type of bonding in SbI 3 changes to become more ionic and hence more similar to the bonding in BiI 3 . This change in structure is supported by a change in the slope of the absorption-edge photon energy versus pressure.

The pressure dependence of the Raman and luminescence spectra of $2H\ensuremath{-}{\mathrm{PbI}}_{2}$ has been studied under hydrostatic pressure up to 1.5 GPa at 77 K by using a diamond-anvil cell. A structural phase transition occurs at a pressure of ${P}_{\mathrm{PT}}=0.56\ifmmode\pm\else\textpm\fi{}0.01 \mathrm{GPa}.$ From the analysis of the Raman spectra, it is proposed that the unit cell of the high-pressure phase is a $2\ifmmode\times\else\texttimes\fi{}2$ supercell of that of the low-pressure phase. The peak energies of the free exciton recombination and donor-acceptor pair bands shift continuously across the phase transition, indicating that relative positions of atoms and the nature of interatomic bonding hardly change at the phase transition. The pressure dependence of the fundamental absorption edge which is well described by the Urbach rule has also been examined at 77 and 300 K. At ${P}_{\mathrm{PT}}$ the steepness constant ${\ensuremath{\sigma}}_{0}$ in the Urbach tail changes drastically from 1.70 to 0.63. This result is consistent with the proposed doubling of unit-cell dimensions at ${P}_{\mathrm{PT}}.$

The pressure dependence of Raman spectra of AsI 3 single crystals has been studied under hydrostatic pressure up to 2.23 GPa at 77 K by using a diamond anvil cell. The number of Raman lines increased abruptly at a pressure of 1.66 GPa indicating a structural phase transition. Further analysis of the Raman spectra in the high-pressure phase suggests that the new unit cell is made of two nearly identical unit cells of the low-pressure phase.

For fine particles of semiconductive rutile TiO 2 supporting ultra-fine particles of Pt which were prepared by decomposing a colloidal organic-Pt complex, the structural aspects of the high photoactivity were examined by high resolution imaging, X-ray mapping by energy dispersive spectroscopy and electron energy-loss spectroscopy. As a result, the Pt particles with nm-sizes were found to grow epitaxially on rutile, which supports an expected mechanism that the photo-excited electrons efficiently transfer from TiO 2 to Pt and promote the reduction of O 2 to O 2

Size-distributed BiI 3 microcrystallites embedded in CdI 2 matrices were formed from melt-grown mixed crystals through the aggregation of BiI 3 molecules by an annealing treatment at a fairly low temperature. Electronic transitions in initially existing two-molecule clusters of BiI 3 were analyzed on the basis of intracation transitions of the metal. The microcrystallites of BiI 3 have a disk-like shape of various radii with the unit layer thickness, which were directly observed by a high resolution electron microscope. Absorption, luminescence and luminescence-excitation spectra for the microcrystallites are presented. We observed Stokes-shifted luminescence from the BiI 3 microcrystallites for the first time. The magnitude of Stokes-shifts changes depending on the microcrystallite size. From the results, it is concluded that the exciton-phonon interaction becomes stronger with the decrease of the microcrystallite size.

The optical response of excitons confined in characteristic nanostructures in layered metal tri-iodide crystals introduced by some irregular stackings from the bulk structures is reviewed. In BiI 3 a specific stacking fault takes place during crystal growth constructing macroscopic planar defects. In this space conspicuous localized exciton transitions occur below the intrinsic absorption edge. Another stacking disorder introduced by applying external stress in this crystal brings about a new nanostructure domain of symmetry D 3d different from that of bulk symmetry C 2 3i . The optical transitions due to new structures appear in the lower energy region as an absorption and luminescence line series. The similar nanostructures are induced in SbI 3 crystals under the hydrostatic pressure. In these nanostructures, the electronic structure is analyzed by a model based on the confined excitons in a nanoscale disk-like shape space. The magnetic field effect confirms the structure in the wave function-size scale. The nanoscale disk-like structure of BiI 3 in CdI 2 matrices is also obtained by a hot wall technique and mixed crystal annealing, which is realized by observing the size distribution with an electron microscope. In a BiI 3 disk in CdI 2 Stokes shifted photoluminescence bands appear. The Stokes shifts of the luminescence bands are understood by considering the size-dependent exciton-phonon interaction. In these nanostructures large optical nonlinearity under the intense laser field was obtained.

The size effects on the exciton absorption and luminescence spectra are studied in nanostructure of BiI 3 embedded in the matrices of bulk BiI 3 and CdI 2 crystals. The quantum-confined exciton states are observed as the absorption lines of the series W J (J=I, II, III, …). The results are compared with a model calculation of the confined excitons in the disks with thickness L z and radius R. The disk-size distribution is directly observed with a high-resolution electron microscope. The relaxed luminescence from the BiI 3 disks in CdI 2 matrix is analyzed by the model of the confined excition interacting with acoustic phonons by taking into account the size-dependent Stokes shift and the distribution of the disk size.

Macroscopic and efficient spreading of excitons from an exciting laser spot to the outside area along a quasi two-dimensional space of a planar-defect in BiI3 is presented by space and time-resolved photoluminescence, and the degenerate Four-Wave-Mixing (DFWM) signals by use of spatially separated two laser-beams. The photoluminescence shows wide spreading due to polariton-like transfer of excitons at low density and wider that at higher density. The fast transfer of excitons at high density was detected as a coherent exciton-flow by the DFWM measurements.

Microcrystallites and ultra-thin films of Bil 3 embedded in CdI 2 crystals were prepared by the melt-growth method and the hot wall technique. Absorption spectra and Stokes-shifted photoluminescence bands of the excitons confined in those are presented. The Stokes-shifts and the temporal behavior of the luminescence bands are understood by considering the size-dependent exciton-lattice interaction and the size-dependent radiative decay rate. These results are compared with model calculations.

Macroscopic exciton transport phenomena from a small area of an exciting laser spot to outside the spot along a quasi-two-dimensional planar defect in BiI 3 , are presented from space-resolved pump-probe absorption, photoluminescence, and four-wave-mixing measurements. At high intensity, the blue shift of the transition energy at the point away from the pump spot is analyzed by the 2-D diffusion. The four-wave-mixing signals are detected with time delays when the two laser beams are spatially separated.

The magnetic field dependence of exciton photoluminescence intensity was investigated in GaAs/AlGaAs superlattice and quantum well structures for high magnetic fields up to 40 T. We discuss the observed large magnetic field effects in terms of the dynamical process of the miniband carriers and excitons under magnetic fields.

We have succeeded in growing BiI 3 –CdI 2 multilayer structures by the hot wall technique. Optical absorption spectra were measured around the band-edge exciton energy of BiI 3 . The absorption peak due to the exciton transition exhibited a splitting and energy shifts in multilayer samples depending on the BiI 3 film thickness. The higher-energy component was assigned to an exciton transition at interface layers. We also observed exciton transitions in ultra-thin films with thicknesses of a few unit-layers. These phenomena were analyzed by a model considering both exciton localization and a site shift effect.

A spectral change of the self-trapped exciton luminescence (4.3 and 3.7 eV bands) in CsI has been observed at 4.2 and 77 K under hydrostatic pressure up to 1 GPa. The result is discussed in connection with the pressure shifts of the energies of the (Γ - 8 , Γ + 6 ) and (Γ - 8 , Γ + 8 ) excitons with the s-like and d-like electron states, respectively.

Saturation spectra of the excitons confined and localized at several kinds of stacking disorders in layered crystal BiI 3 are studied. The quasi-two dimensional exciton localized at the stacking fault interface does not saturate its absorption strength below the density of 10 5 W/cm 2 due to the large binding energy and the lateral center-of-mass motion along the interface. On the exciton system associated with some polytypic structures contained in a very small region, an obvious absorption saturation is observed. The behaviour of absorption saturation is well described by a saturation erect on a simplified two-level system having a homogeneous line broadening. An absorption saturation is also observed on the confined excitons in mesoscopic domains induced by the external deformation of the crystal. The pumping-laser photon-energy dependence of the saturation density characterizes this exciton system to be inhomogeneous

Magneto-optical spectra for various types of excitons localized at two-dimensional (2D) defects in BiI 3 crystals were investigated in pulsed high magnetic fields up to 42 T. The localized excitons were observed as very sharp lines below the indirect exciton energy. For all these exciton transitions, we have observed common features such as very large anisotropy with respect to both the magnetic-field direction and the incident light polarization, characteristic energy shifts to high or low energy side with B 2 dependence, and growth of new lines with increasing fields. The observed magnetic-field effects were interpreted in terms of the Zeeman terms of cationic excitons perturbed by various kinds of stacking disorders that have 2D characters

Optical absorption and photoluminescence due to excitons in BiI 3 crystals have been measured under hydrostatic pressures up to 1.5 GPa at 77 K and 300 K. The direct exciton absorption band shows a red shift under pressure with a coefficient of -1.0×10 2 meV/GPa. The low energy tail of this band obeys the Urbach rule under all pressures. The steepness coefficient σ in the Urbach rule increases from 1.03 to 1.22 as pressure increases from atmospheric pressure to 1 GPa. The intensity of a photoluminescence from a self-trapped exciton state diminishes with increasing pressure, which is complemented by strengthening of the band edge photoluminescence. The behavior of the photoluminescence intensities and the steepness coefficient under pressure is discussed in terms of the instability of the self-trapped exciton state due to the change in the exciton-phonon interaction.

Energy transfer from the triplet state of the bulk exciton to the exciton states localized at a stacking fault interface (stacking fault exciton; SFE) in BiI 3 crystals is investigated by observing the temporal behavior and space-resolved spectra of their resonant luminescence. The recombination luminescence with decay time constant of 1.5 nsec from the triplet exciton appears in the sample having the SFE transition, by taking the SFE states as intermediate states. For the excitation at the indirect exciton region, one of the SFE luminescence shows a slow decay with the same time constant as that of the triplet state in addition to an intrinsic fast decay component with the time constant of 40 psec. The space-resolved luminescence spectra indicate that the triplet excitons transport their energy far from the exciting light spot and transfer it to the SFE states efficiently.

The absorption spectra and the dephasing times of the multiple exciton states localized at a stacking fault in BiI 3 crystals have been measured in the temperature range between 2 and ∼30 K. The dephasing processes can be quantitatively understood by comparing the absorption spectra in the frequency domain with the dephasing times in the time domain. The widths of the absorption spectra are confirmed to be homogeneous broadening from the fact that absorption spectra show excellent agreement with the Lorentzian line shape. The sample dependence of the linewidths reveals the lifetime broadening by sample-dependent imperfection scattering

An exciton confined at a two-dimensional stacking fault in Bi13 crystal reveals large optical nonlinearity and ultra fast response for high density excitation. It shows three resonant luminescences whose decay-time constants are 20ps, 40ps and 900ps from the higher energy states reflecting cascade-type relaxation processes. By the degenerate four-wave mixing (DFWM) measurements, the dephasing times of three exciton states were obtained as 8.6ps, 15ps and 34ps. The dephasing at the lowest state is governed mainly by the LA-phonon intra-band scattering. While, at the higher states, it is governed by the cascade relaxation to the lower states in addition to the phonon scattering. It is found that the dephasing is also influenced by the exciton-exciton scattering under the high density excitation. A nonlinear transition involving a multi-photon process is observed in the excitation response of the DFWM signal. This result suggests the existance of the excitonic molecule.

Absorption line series WJ(J=I,II,III,…) appeared below the indirect, edge in BiI3 has been studied. The series is assigned to the excitons confined in mesoscopic domains produced by deformation fau...

We report the picosecond time resolved spectra of the optical Stark effect on a quasi-two-dimensional exciton localized at a stacking fault plane in Bil3 crystals. The ultrafast response of the blue-shift due to the optical Stark effect(OSE) is confirmed in picosecond time domain under negative detuning excitation condition. For positive detuning excitation, an ultrafast switching from the red shift by the OSE to the blue-shift due to the nonlinear interaction with the large amount of incoherent “real” exciton occurs. Under the just resonance excitation, the blue-shift due to the “real” exciton is also observed during several tens of picoseconds after the pumping, and an absorption bleaching occurs at the timing of the pump-pulse peak. The bleaching is discussed in connection with the OSE.

A study is made of the optical Stark effects on quasi two-dimensional excitons localized at a stacking fault in layered crystal BiI 3. The dynamic coupling of the driven ground states and driven multiple exciton states by the strong photon field occurs for a wide frequency range of light, from negative to positive detuning. For the positive detuning excitation, an additional nonlinear effect peculiar to condensed matter was also observed. Time-resolved measurements in the sub-nanosecond and picosecond time domains confirmed ultrafast switching between the optical Stark effect and the additional nonlinear effect. From the dependence of the optical Stark shift on the excitation intensity, it is shown that the quasi two-dimensional excition transition has a very large dipole matrix element and third-order nonlinear susceptibility χ(3).

Highly resolved excitation spectra for the self-trapped exciton luminescence (σ, π, and E x bands) and for the 1s free exciton luminescence under the two-photon absorption have been studied in RbI at 2 K. These spectra are composed of broad peaks with fine structures: the broad peaks are attributed to the 2p-, 3p- and 4p-exciton transitions, and the fine structures to the energy splitting of the 2p-exciton state by the envelope-hole coupling. The shapes of these excitation spectra are explained by the process of the two-photon absorption with the simultaneous creation of an LO phonon and by the energy relaxation of the p excitons. The former process is treated with third order perturbation theory.

The exciton photoluminescence from two CdTe quantum wells with the thicknesses 4 and 8 nm in CdTe/CdMnTe structures is studied in the magnetic field up to 41 T. The transformation of the photoluminescence spectrum depends strongly on the field direction and degree of the initial exciton localization. The criterion of strong field for the diamagnetic excitons related to the Landau levels is achieved.

Quantum confinement effects and nonlinear luminescence of excitons in CuI microcrystallites on the substrates of poly-methyl methacrylate have been studied. Exciton transitions due to the hexagonal structure appear in the disk-shaped microcrystallites. The confinements of the relative motion of excitons in the hexagonal structure induce remarkable blue-shifts of the transition energy. From the size dependence of their confinement energies, reduced mass ratios of the hexagonal excitons were obtained. Under high-density excitation, a new luminescence band grows super-linearly at the energy position lower by ∼30 meV than the exciton resonance. The origin of the luminescence was assigned to an annihilation of bi-excitons in the hexagonal structure.

Exciton–phonon interaction parameters in layered metal iodide crystals, BiI3, SbI3 and PbI2, have been estimated from the measurements of the steepness constants σ0 in the Urbach tails of absorption edge spectra under hydrostatic pressure. Luminescence from self-trapped exciton (STE) and free exciton (FE) states in these crystals has been examined under pressure. Simple but reasonable interpretation for the drastic change in the luminescence as well as in the interaction parameter values is given in terms of excitonic band anomaly.

On the exciton states localized at a two-dimensional stacking fault interface in a layered crystal BiI3, some nonlinear optical phenomena clearly appear reflecting large transition probability. The optical Stark shift and other high density exciton effect on the energy-shift and the spectral broadening are observed with clear separation under intense laser pumping by time-resolved measurements. The optical Stark shift is analyzed based on the dressed exciton model. The ultrafast optical response faster than 3 ps for the pump-laser field is confirmed on the Stark shift. Degenerate four-wave-mixing signals show fairly long dephasing time of ∼40 ps in this system. The dephasing probability depends linearly on the pump-laser intensity in the same manner as that of the spectral line-broadening reflecting the relaxation process. The dephasing mechanisms are understood by the exciton scattering at high density in parallel with the spectral changes. The blue-shift due to the high density excitons are discussed on the basis of exciton-exciton interaction in connection with a phase-space filling theory in two-dimensional systems.

Les anticroisements des niveaux concernant l'etat fondamental du cristal, ainsi que les etats excitoniques multiples sont clairement observes dans le large domaine des frequences d'excitation laser - partant des frequences en dehors de la resonance jusqu'a la resonance - des etats excitoniques. Ce resultat est bien decrit sur la base du modele des excitons multiples «habilles». Discussion d'une modification spectrale supplementaire, en liaison avec la population reelle des excitons

Fast and ballistic spreading of excitons excited at the stacking fault interface in BiI3 crystals was observed in the temporal behavior of exciton luminescence with space- and time-resolved measurements. The spreading velocity reaches ∼7 × 108 cm/s, indicating rapid energy transfer by an exciton-polariton along the layer plane. Time-of-flight measurements were also performed in this system, in the direction parallel to the crystal layer containing the stacking fault. Wavelength-sensitive time delay was detected in the picosecond time domain in the stacking fault exciton transition region. A group velocity of 6 × 108 cm/s is obtained, corresponding to the fast exciton propagation observed on the luminescence. An apparent anomaly in the times-of-flight of different excitons is shown to be related to the polarization dependence of the absorption spectra.

We have studied the luminescence properties of LiBr crystals cleaved at 6 K. A drastic change of the luminescence spectrum on cleaving is found; the 5.4 eV band, which has been assigned to be the σ band originating from the singlet self-trapped exciton (STE), disappears, and the 3.95 eV band, known to be the π band from the triplet STE, is enhanced, implying that the 5.4 eV band is extrinsic and only the 3.95 eV band with π character is intrinsic. We also conclude that the holes in LiBr are mobile and migrate to impurities to recombine with electrons there, emitting the 5.4 eV luminescence.

We have observed a surface exciton transition in the absorption spectra of thin films single crystals of BiI 3 grown by use of a recently developed hot wall method. The energy position of the surface exciton was 50 meV higher than that of the direct exciton. The intensity and the half-width of the surface exciton were evaluated to be 0.1 O.D. and less than 20 meV, respectively.

The temperature dependence and the polarization character of the second-order Raman spectra have been studied in LiI single crystals. The principal phonon energies of acoustic and optic modes at critical points in the Brillouin zone are determined with a help of calculated phonon dispersion curves. The second-order Raman spectra at 290 K in LiBr, LiCl and LiF crystals are also observed and analyzed. A characteristic feature of lattice dynamics in lithium halides is discussed.

ヌードマウス移植ヒト悪性黒色腫(SK-14株)に対し, MY-1の腫瘍内投与, および皮下投与はいずれも優れた抗腫瘍効果を示した。病理形態学的には腫瘍細胞の変性と核クロマチンの変化に続く細胞変性壊死, マクロファージの出現が顕著であった。腫瘍内MY-1濃度をDNAプローブ法により測定したが, MY-1は腫瘍内から速やかに消失した。MY-1は有用性が充分期待でき, 今後臨床的にも広範に検討すべき薬剤と判断された。

ヌードマウス可移植性ヒト悪性黒色腫 (SK-14) に対してBCG生菌の抗腫瘍効果を検討した。移植腫瘍の成長を確認後, コントロール群 (生理的食塩水) , BCG生菌の1mg群および2.5mg群に分け, 皮下投与と腫瘍内投与により腫瘍増殖抑制効果を比較検討した。これによるとBCG生菌投与群ではコートロール群に比較して腫瘍の縮小は認めたものの有意の差はなかった。しかし, 病理組織学的所見によればBCG生菌投与群の腫瘍細胞のほとんどが壊死化し, 大量の好中球の出現が認められ, これが腫瘍細胞の崩壊に関与しているのではないかと考えられた。またかかる変化は皮下投与よりも腫瘍内投与の方が強いように思われた。

WPG (whole peptidoglycan) はビフィズス菌の1種であるBifidobacteyiurn infantis由来の新しいBRMである。その作用としてNK活性の増強作用とIL-1誘起能, 局所免疫反応と腫瘍の退縮, 抗腫瘍T細胞の誘導などが知られている。我々はヌードマウス可移植性ヒト悪性黒色腫 (SK-14) およびヒト腎癌 (RCC-1) を移植してWPGの増殖抑制効果を検討した。投与は腫瘍内投与と皮下投与で行い, 連日15回投与後, SK-14は13日目, RCC-1は9日目に切除し, 重量を測定し, コントロールと比較して抑制率を検討した。また, 同時に病理組織学的にも観察した。抑制率はコントロールと比較してそれほど顕著ではなかったが, 皮下投与の方が腫瘍内投与より優れている印象を受けた。また, WPG投与による組織の変化はいずれも腫瘍細胞の壊死が著明で効果は組織的にはPRと考えられた。

Purpose: AZD2171 is an oral, highly potent, and selective vascular endothelial growth factor signaling inhibitor that inhibits all vascular endothelial growth factor receptor tyrosine kinases. The purpose of this study was to investigate the activity of AZD2171 in gastric cancer.Experimental Design: We examined the antitumor effect of AZD2171 on the eight gastric cancer cell lines in vitro and in vivo.Results: AZD2171 directly inhibited the growth of two gastric cancer cell lines (KATO-III and OCUM2M), with an IC50 of 0.15 and 0.37 μmol/L, respectively, more potently than the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib. Reverse transcription-PCR experiments and immunoblotting revealed that sensitive cell lines dominantly expressed COOH terminus–truncated fibroblast growth factor receptor 2 (FGFR2) splicing variants that were constitutively phosphorylated and spontaneously dimerized. AZD2171 completely inhibited the phosphorylation of FGFR2 and downstream signaling proteins (FRS2, AKT, and mitogen-activated protein kinase) in sensitive cell lines at a 10-fold lower concentration (0.1 μmol/L) than in the other cell lines. An in vitro kinase assay showed that AZD2171 inhibited kinase activity of immunoprecipitated FGFR2 with submicromolar Ki values (∼0.05 μmol/L). Finally, we assessed the antitumor activity of AZD2171 in human gastric tumor xenograft models in mice. Oral administration of AZD2171 (1.5 or 6 mg/kg/d) significantly and dose-dependently inhibited tumor growth in mice bearing KATO-III and OCUM2M tumor xenografts.Conclusions: AZD2171 exerted potent antitumor activity against gastric cancer xenografts overexpressing FGFR2. The results of these preclinical studies indicate that AZD2171 may provide clinical benefit in patients with certain types of gastric cancer.

We present transport properties of excitons at high density in a quasi-two-dimensional space of a specific stacking disorder interface in layered crystal BiI 3 , observing temporal behavior and peak energy shifts in space- and time-resolved luminescence spectra. Coherent transport component was resolved as a ballistic wave front of exciton-polariton with a very large group velocity. On the other hand, incoherent exciton transport is responsible for the relatively slower component in the space-resolved regime.

Raman absorption of the exciton and luminescence from self-trapped exciton in SbI 3 and BiI 3 have been investigated under hyrostatic pressure. The difference in the nature of intra-layer bonding between these materials brings about the difference in the exciton-transition-energy shifts and the relaxation process of the excitons under pressure.

The high density effects of excitons excited at a two-dimensional stacking-fault plane in layered BiI3 crystal is investigated. The blue-shift and broadening have been observed for the high density excitation. A new transition appears below the resonance exciton energies, which is attributed to the two-photon transition to a bi-exciton state.

Anisotropic migration of triplet excitons in a layered BiI 3 crystal has been investigated. The triplet excitons migrate over several hundred micrometers along the layer plane. On the other hand, they do not transfer their energy more than 10 μm in the layer-stacking direction.

In the previous communication(11), we reported that prior O2 breathing lasted for 10 min effectively augmented the subsequent ventilatory level in isocapnic sustained hypoxia. In addition, we found that involvement of a humoral agent, excitatory amino acid glutamate, may be responsible for inducing this phenomenon.