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Atypical chest pain and diabetic autonomic neuropathy attract less clinical attention, leading to underdiagnosis and delayed treatment. To evaluate the long-term clinical impact of atypical chest pain and diabetes mellitus (DM), we categorized 11,159 patients with acute myocardial infarction (AMI) from the Korea AMI-National Institutes of Health between November 2011 and December 2015 into four groups (atypical DM, atypical non-DM, typical DM, and typical non-DM). The primary endpoint was defined as patient-oriented composite endpoint (POCE) at 2 years including all-cause death, any myocardial infarction (MI), and any revascularization. Patients with atypical chest pain showed higher 2-year mortality than those with typical chest pain in both DM (29.5% vs. 11.4%, p &lt, 0.0001) and non-DM (20.4% vs. 6.3%, p &lt, 0.0001) groups. The atypical DM group had the highest risks of POCE (hazard ratio (HR) 1.76, 95% confidence interval (CI) 1.48&ndash, 2.10), all-cause death (HR 2.23, 95% CI 1.80&ndash, 2.76) and any MI (HR 2.34, 95% CI 1.51&ndash, 3.64) in the adjusted model. In conclusion, atypical chest pain was significantly associated with mortality in patients with AMI. Among four groups, the atypical DM group showed the worst clinical outcomes at 2 years. Application of rapid rule in/out AMI protocols would be beneficial to improve clinical outcomes.

3C-SiC is the only polytype that grows heteroepitaxially on Si substrates and, therefore, it is of high interest for various potentail applications. However, the large (~20 %) lattice mismatch of SiC with the Si substrate causes a serious problem. In this respect, rotated epitaxy of 3C-SiC(111) on the Si(110) substrate is highly promising because it allows reduction of the lattice mismatch down to a few percent. We have systematically searched the growth conditions for the onset of this rotated epitaxy, and have found that the rotaed epitaxy occurrs at higher growth temperatures and at lower source-gas pressures. This result indicates that the rotated epitaxy occurs under growth conditions that are close to the equilibrium and is thefore thermodynamically, rather than kinetically, driven.

In the formation of epitaxial graphene on Si substrates, the growth of high-quality 3C-SiC thin films on Si substrates is a key to success. As a solution to the large mismatch between the Si substrate and the 3C-SiC film, rotated epitaxy in which 3C-SiC(111) films are grown on Si(110) substrates is quite attractive. In some applications, on the other hand, a certatin thickness (~100 nm or more) is required for this 3C-SiC films as well. A two-step growth method has been thus developed to realize a high-rate, qualified rotated epitaxy. A qualified graphene is found to be formed on this rotated epi-film, as typified by the increase of the grain size by a factor of 1.6 from the non-rotated epitaxy.

Synthesis of a new series of diarylureas and diarylamides having 1 H -pyrrolo[3,2- c ]pyridine scaffold is described. Their in vitro antiproliferative activity against A375P human melanoma cell line was tested and the effect of substituents on pyrrolo[3,2- c ]pyridine nucleus was investigated. The newly synthesized compounds, except three N -tolyl derivatives ( 8f , 9f , and 9h ), generally showed superior activity against A375P to Sorafenib. Among all of these derivatives, compounds 8b , 8g , and 9a–e showed the highest potency against A375P with IC 50 in nanomolar range. In addition, compounds 8d , 8e , 8h , 9g , 9i , and 9j were more potent than Sorafenib but with IC 50 in micromolar range. Compounds 8b , 8g , 9b–d , and 9i demonstrated higher selectivity towards A375P compared with NIH3T3 fibroblasts. The most potent diarylurea 8g and diarylamide 9d were further tested and showed high potency over nine melanoma cell lines at the NCI.

We report on the fabrication and transport characteristics of nanoscale stacked-junctions of thin graphite flake. The stacked-junctions were fabricated using a three-dimensional focused-ion-beam milling. By varying the effective in-plane area down to submicron scale, the stacked-junctions with in-plane area A (from 2 down to 0.25 μm 2 ) and stack height–length (from 300 to 100 nm) along c -axis were fabricated. The nano-stack shows perfect c -axis transport characteristics in which we observed a semiconducting behavior for T > 65 K and metallic behavior for T c -axis electrical conduction mechanism. The stack with in-plane area A of 0.25 μm 2 showed nonlinear concave-like I – V characteristics even at 300 K; however the stack with A ⩾ 1 μm 2 were shown an ohmic-like I – V characteristic at 300 K for both low and high-current biasing. It turned into nonlinear characteristics when the temperature goes down. The observation of this anomalous transport characteristics were discussed in detail with stack capacitance calculations. The nonlinear characteristics observed at 300 K for the stack with A of 0.25 μm 2 were shown best fit with Fowler–Nordheim tunneling model.

Synthesis of a new series of diarylureas and amides having pyrrolo[3,2-b]pyridine scaffold is described. Their in vitro antiproliferative activity against human melanoma cell line A375 and HS 27 human fibroblast cell line was tested and the effect of substituents on the pyrrolo[3,2-b]pyridine was investigated. The newly synthesized compounds, except meta-substituted derivatives (Ij-k and Iv-w), generally showed superior or similar activity against A375 to Sorafenib. Among all of these derivatives, compounds Ir and It having 5-benzylamide substituted 4'-amide moieties showed the most potent antiproliferative activity against A375.

Tunneling barrier engineered charge trap flash (TBE-CTF) memory devices were fabricated using the tunneling barrier engineering technique. Variable oxide thickness (VARIOT) barrier and CRESTED barrier consisting of thin SiO 2 and Si 3 N 4 dielectric layers were used as engineered tunneling barrier. A faster program/erase speed as well as a larger memory window was achieved from the TBE-CTF memory. The VARIOT-type tunneling barrier composed of oxide–nitride–oxide (ONO) layers revealed a longer retention time and superior endurance characteristic. On the other hand, the CRESTED tunneling barrier composed of nitride–oxide–nitride (NON) layers showed degraded retention and endurance characteristics. It is found that the degradation of NON barrier is associated with the increase of interface state density at the tunneling barrier/silicon channel by programming and erasing ( P / E ) stress.

Synthesis of a new series of diarylureas and amides having pyrrolo[2,3-d]pyrimidine scaffold is described. Their in vitro antiproliferative activities against A375 human melanoma cell line and HS 27 fibroblast cell line were tested and the effect of substituents on pyrrolo[2,3-d]pyrimidine was investigated. The newly synthesized compounds, except N-acetyl derivatives (Id, Ie, and Im), generally showed superior or similar activity against A375 to Sorafenib. Among all of these derivatives, compounds Iq and Ir having imidazole and morpholine moieties, respectively, showed the most potent antiproliferative activity against A375.

The electrical characteristics of thin strained-silicon-on-insulator (sSOI) wafers were evaluated, and the effects of annealing processes on the back interface states of sSOI wafers were analyzed by using the back-gated (BG) metal-oxide-semiconductor field-effect-transistor structure. The electrical characteristics of the BG MOSFET fabricated on sSOI wafers were superior to that of conventional SOI wafers. However, the rapid thermal annealing (RTA) process induced significant degradations by increasing the back interface states between the strained-Si thin channel and the buried oxide layer. On the other hand, the conventional furnace annealing process at 500degC in a nitrogen (N2) ambient was effective for reducing the RTA-induced back interface states, and the performances of the BG sSOI MOSFET annealed in N2 ambient were significantly improved.

The synthesis of a new series of 1beta-methylcarbapenems having pyrrolidine and piperidine moieties is described. Their in-vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents on the pyrrolidine ring was investigated. A particular compound III b having an oxime-pyrrolidine moiety showed the most potent antibacterial activity.

E-mail: choh@kist.re.krReceived August 20, 2008The synthesis of a new series of diaryl ureas having a pyrrolo[2,3-d]pyrimidine scaffold is reported here. Thein vitro antiproliferative activities of these diaryl derivatives against human melanoma cell line A375 weretested and the effect of substituents on the phenyl ring was investigated. The para substituted compounds Ia-gshowed superior or similiar activity to Sorafenib against the A375 cell line. Among these compounds, Ic-eshowed excellent activity against A375 compared with Sorafenib, a multi-kinase inhibitor.Key Words : Pyrrolo[2,3-d]pyrimidine, A375, Antiproliferative activityIntroductionMelanoma, the most aggressive form of skin cancer, is thefastest growing cancer in the United States.

Objectives To investigate the epidemiologic and microbiological characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infections in the otorrhea of chronic suppurative otitis media (COM) patients. Design Retrospective study of patients with newly identified MRSA infections from January 1998 through December 2006. A total of 2773 patients with a diagnosis of COM were included in this study. An antibiotic sensitivity test was performed for each isolate. Results The prevalence of MRSA in COM was 4.9 percent (137 of 2773 patients). The proportion of CA-MRSA rose from 0.7 percent in 1998 to 11.4 percent in 2006. However, the proportion of HA-MRSA did not change significantly, from 0.7 percent in 1999 to 1.3 percent in 2006. All of the CA-MRSA strains identified in our study were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX). Rifampin susceptibility was also noted in 90 percent of the cases. Conclusions CA-MRSA infections have risen dramatically in the past decade. CA-MRSA and HA-MRSA in COM differed in both clinical and microbiological aspects.

The synthesis of a new series of 1-methylcarbapenems having spiro[2,4]heptane moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents at the pyrrolidine ring was investigated. Most of the compounds were found to be more active compared to imipenem against Gram-negative bacteria. A particular compound (IIIc) having 7-oxo-5- azaspiro[2,4]heptane moiety showed the most potent antibacterial activity.

The advent of 193 nm ArF lithography opened new era of sub-90 nm patterning in DRAM industry. ArF lithography in single layer scheme, however, has limitation in the substrate fabrication of sub-90 nm L/S due to the decreased physical thickness of resist less than 3000A and weak chemical structure of resist. Bi-layer scheme, composed of Si-containing top layer and thick organic bottom layer, is gaining attention for its capability of patterning and control of resist thickness as a substitute for single layer. Several resists were evaluated for bi-layer process in terms of resolution, dry development, bottom layer durability and SEM induced CD shrinkage. Resolution down to 80 nm was achieved with Si content ranging from 8 to 9%. Etch selectivity in the dry development was a strong function of Si content and chemical structure of top layer with pitch size dependence based on O2/N2 gas chemistry in dual frequency plasma tool. Profile control after dry development was subject to change depending on the gas ratio (O2/N2) and power. Resist structure was proved to be a key factor in bottom resist durability at the substrate etch condition. Best combination of top and bottom resists in bi-layer scheme will be discussed.

The results of S–dH measurements and the observation of quantum Hall plateaus at 1.5 K clearly demonstrated the existence of a 2DEG in modulation-doped Al x Ga 1− x As/In y Ga 1− y As/GaAs asymmetric step quantum wells. The PL data measured at several temperatures showed that the excitonic transition from the ground electronic subband to the ground heavy-hole band (E 0 –HH 1 ) shifted to the lower energy side with increasing temperature. The value of the (E 0 –HH 1 ) excitonic transition obtained from the PL measurements was in reasonable agreement with that determined from self-consistent calculations.

Spectroscopic ellipsometry and photoluminescence (PL) measurements on SnO2 nanocrystalline textured films grown on p-InSb (111) substrates by using radio-frequency magnetron sputtering at low temperature were carried out to investigate the dependence of the optical parameters on the SnO2 thin film thickness. As the SnO2 film thickness increases, while the energy gap of the SnO2 film decreases, its refractive index increases. The PL spectra show that the broad peaks corresponding to the donor–acceptor pair transitions are dominant and that the peak positions change with the SnO2 film thickness. These results can help improve understanding for the application of SnO2 nanocrystalline thin films grown on p-InSb (111) substrates in potential optoelectronic devices based on InSb substrates.

The microsturctural properties in lattice-mismatched InAs 0.3 P 0.7 /InP modulation-doped single quantum wells were investigated by using transmission electron microscopy (TEM) and the Raman scattering spectroscopy measurements, and the low-temperature magnetotransport properties of the two-dimensional electron gas (2DEG) in the InAs 0.3 P 0.7 wells were studied using Shubnikov–de Haas (S–dH) and Van der Pauw Hall-effect measurements. The TEM measurement on the InAs 0.3 P 0.7 /InP single quantum wells showed that the InAs 0.3 P 0.7 active layer was grown pseudomorphologically on the InP buffer layer in spite of the lattice mismatch. The values of the horizontal, the vertical strains and the horizontal stress of the InAs 0.3 P 0.7 layer were −9.6×10 3 , 1.07×10 −2 , and −8.67×10 −2 dyne cm −2 , respectively. A possible crystal structure for the InAs 0.3 P 0.7 /InP single quantum well is presented on the basis of the TEM results. The S–dH measurements and the fast Fourier transformation results for the S–dH data clearly indicate electron occupation of one subband in the InAs 0.3 P 0.7 /InP single quantum well. The carrier density and the effective mass of the 2DEG as determined from the S–dH measurements were 5.71×10 11 cm −2 and 0.06256 m 0 , respectively. The electronic structures in the quantum wells were calculated by using a self-consistent method. These present results can help improve the understanding of potential applications of modulation-doped InAs x P 1− x /InP strained single quantum wells in high speed electronic devices.

Transmission electron microscopy images showed that multiply stacked CdSe quantum-dot (QD) arrays with a large ZnSe spacer thickness were embedded in the ZnSe barriers. The temperature-dependence photoluminescence (PL) spectra showed that the peak corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole band of the CdSe QDs shifted to a lower energy side with increasing temperature and that the PL linewidth at high temperature increased with increasing temperature. The activation energy of the electrons confined in the CdSe QDs was as large as 100 meV. The present observation can help improve understanding of the microstructural and optical properties in multiply stacked CdSe/ZnSe QDs.

Photoluminescence (PL) measurements on the CdTe/ZnTe strained single quantum wells grown by using the molecular beam epitaxy technique showed that the sharp excitonic peaks corresponding to the transition from the first electronic subband to the first heavy-hole (E 1 –HH 1 ) were shifted to lower energy with increasing well width. The (E 1 –HH 1 ) interband transitions were calculated by using an envelope function approximation taking into account the strain effects, and the values were in reasonable agreement with those obtained from the (E 1 –HH 1 ) excitonic transitions of the PL spectra. The activation energies of the confined electrons in the CdTe quantum well were obtained from the temperature-dependent PL spectra, and their values increased with increasing CdTe well width due to the quantum confinement effect. The present results can help to improve the understanding of the activation energies dependent on the CdTe well width in CdTe/ZnTe single quantum wells.

SnO2 thin films on p-InP (1 0 0) substrates were grown at various Ar/O2 flow-rate ratio by using radio-frequency magnetron sputtering at low temperature. Atomic force microscopy images showed that the SnO2 films grown on the InP (1 0 0) substrates at an Ar/O2 flow rate of 0.667 and at a temperature of 250°C had the best surface morphologies among the several samples, and X-ray diffraction and transmission electron microscopy (TEM) measurements showed that the SnO2 thin films grown on the InP (1 0 0) substrates were polycrystalline layers with local epitaxy regions. An electron diffraction pattern and TEM measurements showed that the SnO2/p-InP heterostructures had no significant intermixing problems at the heterointerfaces. The capacitance–voltage measurements at room temperature showed that the majority carrier type of the nominally undoped SnO2 film was n-type and that the carrier concentration of the nominally undoped SnO2 film grown at an Ar/O2 flow rate of 0.667 had a minimum value. Photoluminescence spectra showed that peaks corresponding to the donor–acceptor pair transitions were dominant and that the peak positions changed significantly depending on the Ar/O2 flow rate. These results indicate that the SnO2 epitaxial films grown on p-InP (1 0 0) substrates at low temperature hold promise for potential electronic devices based on InP substrates, such as superior gas sensors, and high-efficiency solar cells.

The variation of the electron carrier occupation and the mobility in the subband as a function of the spacer layer thickness in modulation-doped AlxGa1−xAs/InyGa1−yAs/GaAs strained single quantum wells was investigated by Shubnikov-de Haas (S-dH) and Van der Pauw Hall-effect measurements. The results of the fast Fourier transform (FFT) for the S-dH data and those of the Hall-effect data showed that the magnitude of the electron carrier density in the sub-band increased as the spacer layer became thinner, and the increase in the carrier density with decreasing spacer-layer thickness resulted from an increase in the distance between the Fermi energy level and the top of the depletion layer. The full width at half maxima of the FFT results for the S-dH data and of the results of the Hall-effect measurements indicated that the value of the electron mobility increased as the spacer-layer thickness increased, and the increase in the electron mobility originated from a decrease in the Coulomb interaction between the ionized donors and the electrons. The electronic sub-band energies, corresponding wave functions, and the Fermi energies in the InyGa1−yAs quantum wells were calculated by a self-consistent method taking into account exchange-correlation effects together with the strain and nonparabolicity effects. These present results can help to improve the understanding for the application of AlxGa1−xAs/InyGa1−yAs/GaAs strained single quantum wells in electronic devices such as high-frequency and high-speed field-effect transistors.

A new approach has been introduced for the fabrication of Ru/p-InP(100) heterostructures with the goal of producing stable Ru contacts and sharp Ru/p-InP heterointerfaces. Atomic force microscopy and X-ray diffraction measurements showed that the Ru film layers grown on InP substrates were polycrystalline thin films with very smooth surfaces. Auger electron spectroscopy and Rutherford backscattering measurements showed that the composition of the as-grown film was Ru and that the Ru/InP interface quality was relatively good. Transmission electron microscopy and selected-area electron-diffraction measurements showed that the grown Ru film was a polycrystalline layer with small grain domains. These results can help improve understanding for the application of Ru/InP heterostructures in high-speed metal–semiconductor field-effect transistors.

The determination of the effective mass of the two-dimensional electron gas (2DEG) and nonparabolicity effects in modulation-doped In 0.65 Ga 0.35 As/In 0.52 Al 0.48 As single quantum well were investigated by temperature-dependent Shubnikov–de Haas (S–dH) measurements and fast Fourier transformation (FFT) and the inverse FFT (IFFT) analyses. The result of the angular-dependent S–dH measurements clearly demonstrated the occupation of two subbands in the quantum wells by the 2DEGs. The electron effective masses determined from temperature-dependent S–dH measurements and the FFT and IFFT analyses were 0.05869 and 0.05385 m e for the first and zeroth subbands, respectively. The electron effective masses obtained from the S–dH measurements and the FFT and IFFT analyses measurements qualitatively satisfy the nonparabolicity behavior in the In 0.65 Ga 0.35 As single quantum well. The electronic subband energies, the subband energy wavefunctions, and the Fermi energy in the In 0.65 Ga 0.35 As single quantum wells were calculated by a self-consistent method taking into account the exchange-correlation effect, the strain effect, and the nonparabolicity effect.

The metal-insulator-silicon (MIS) capacitors with and high-k dielectrics (, ) were fabricated, and the current-voltage characteristics were investigated. Especially, an effective barrier height between metal gate and dielectric was extracted by using Fowler-Nordheim (FN) plot and Direct Tunneling (DT) plot of quantum mechanical(QM) modeling. The calculated barrier heights of thermal , ALD , and are 3.35 eV, 0.6 eV, 1.75 eV, and 2.65 eV, respectively. Therefore, the performance of non-volatile memory devices can be improved by using engineered tunnel barrier which is considered effective barrier height of high-k materials.

Shubnikov–de Haas (S–dH), Van der Pauw Hall-effect and photoluminescence (PL) measurements were carried out to investigate the magnetotransport and excitonic transition properties of modulation-doped InxGa1−xAs/InyAl1−yAs asymmetric step quantum well. High-resolution transmission electron microscopy measurements showed a shallow In0.53Ga0.47As well and a deep In0.65Ga0.35As well bounded by two In0.52Al0.48As barriers. The results of S–dH measurements and the observation of the quantum Hall plateaus at 1.5 K demonstrated clearly the existence of a quasi-two-dimensional electron gas (2DEG) in the InxGa1−xAs step quantum wells. The fast Fourier transformation results for the S–dH data indicated clearly that the 2DEG occupied two subbands in the InxGa1−xAs quantum wells. Temperature-dependent PL measurements were performed to characterize the excitonic transition and the Fermi-edge singularity in the InxGa1−xAs strained step quantum well. The electronic subband levels, the corresponding wavefunctions, and the dispersion relations in the InxGa1−xAs/InyAl1−yAs step quantum well were calculated by a self-consistent method which took into account the exchange-correlation effect together with the nonparabolicity and strain effects. These results can help improve understanding for the applications of step quantum wells in high-speed electronic and optoelectronic devices.

Low-temperature electrical transport properties of the two-dimensional electron gas (2DEG) in modulation-doped Al0.25Ga0.75As/In0.18Ga0.82As/In0.25Ga0.75As/GaAs asymmetric step quantum wells were studied by Shubnikov–de Haas (S–dH) and Van der Pauw Hall-effect measurements. The angular dependent S–dH measurements at 1.5 K demonstrated clearly the existence of a quasi-2DEG in the InxGa1−xAs step quantum wells, and the fast Fourier transformation results for the S–dH data clearly indicate the electron occupation of one subband in the Al0.25Ga0.75As/In0.18Ga0.82As/In0.25Ga0.75As/GaAs asymmetric step quantum wells. The electron carrier density and the effective mass determined from the S–dH measurements were 1.76×1012 cm−2 and 0.06603m0, respectively. The electronic subband energy, the energy wavefunction, and the Fermi energy in the InxGa1−xAs step quantum wells were calculated by a self-consistent method taking into account exchange-correlation effects together with the strain and nonparabolicity effects. These present results can help improve understanding for the potential applications of modulation-doped Al0.25Ga0.75As/In0.18Ga0.82As/In0.25Ga0.75As/GaAs asymmetric step quantum wells in new kinds of the high-speed electronic devices.

Photoluminescence (PL) measurements have been carried out to investigate the hydrogenation and annealing effects on the excitonic transitions in modulation-doped Al 0.25 Ga 0.75 As/In 0.18 Ga 0.82 As/GaAs strained quantum wells. After hydrogenation, the PL spectra showed that the excitonic transition energy from the ground electronic subband to the ground heavy-hole subband ( E 0 −HH 1 ) shifted to a higher energy. When the hydrogenated Al 0.25 Ga 0.75 As/In 0.18 Ga 0.82 As/GaAs quantum wells was annealed, the ( E 0 −HH 1 ) peak shifted to a lower energy. The electronic subband energies, the energy wave functions, and the Fermi energies in the as-grown modulation-doped Al 0.25 Ga 0.75 As/In 0.18 Ga 0.82 As/GaAs quantum wells were calculated by a self-consistent method taking into account exchange-correlation effects together with the strain and nonparabolicity effects. These results indicate that the energy levels of the electronic subbands in the In 0.18 Ga 0.82 As quantum well are dramatically affected by the hydrogenation and the annealing and that the shifts of their energy levels due to the hydrogenation and the annealing can help improve understanding of the promising applications of modulation-doped Al 0.25 Ga 0.75 As/In 0.18 Ga 0.82 As/GaAs strained quantum wells in optoelectronic devices.

Shubnikov–de Haas (S–dH) and photoluminescence (PL) measurements on In x Ga 1− x As/In y Al 1− y As modulation-doped coupled double quantum wells with a 100 A In 0.65 Ga 0.35 As well and a 100 A In 0.53 Ga 0.47 As quantum well separated by a 35 A In 0.25 Ga 0.75 As embedded potential barrier were carried out to investigate both the existence of a two-dimensional electron gas (2DEG) and the excitonic transitions in the quantum wells. The S–dH oscillations and the observation of quantum Hall steps at 1.5 K demonstrated clearly the existence of a 2DEG in the In x Ga 1− x As double quantum well and the fast Fourier transformation results for the S–dH data indicated clearly that the 2DEG occupied two subbands in the In x Ga 1− x As double quantum well. Temperature-dependent PL spectra showed several excitonic transitions and a Fermi-edge singularity in the In x Ga 1− x As/In y Al 1− y As double quantum well. The electronic subband energies, the corresponding wave functions and the Fermi energy in the In x Ga 1− x As/In y Al 1− y As double quantum wells were calculated by using a self-consistent method taking into account exchange-correlation effects together with the strain and the nonparabolicity effects. The calculated electronic subband structures are in reasonable agreement with the results of the S–dH and the PL measurements. These results indicate that modulation-doped In x Ga 1− x As/In y Al 1− y As double quantum wells hold promise for potential applications such as new types of pseudomorphic high electron mobility transistors.

The variation of the electron carrier occupation in the subband as a function of the As mole fraction and strain effects on the modulation-doped InAs x P 1-x /InP single quantum wells have been studied. The results of the fast Fourier transform (FFT) for Shubnikov-de Haas (S-dH) data showed that the magnitude of the electron carrier density in the subband increased as the As mole fraction increased. The full width at half maxima of the FFT results for the S-dH data and the results of the Hall-effect measurements indicated that the value of the electron mobility increased as the As mole fraction increased. The electronic subband energies, the subband energy wavefunctions, the Fermi levels, and carrier densities in the InAs x P 1-x quantum wells were calculated by a self-consistent method taking into account the exchange-correlation effects and the nonparabolicity effect together with and without the strain effect. The calculated subband carrier densities which included the strain effect were in more reasonable agreement with those determined from the S-dH and the Hall-effect experiments. The increase of the electron mobility and carrier density with increasing As mole fraction results from the decrease of the electron effective mass and the increase of the conduction band offset, respectivley. In particular, the calculated subband carrier density in the InAs 0.6 P 0.4 /InP highly strained quantum well taking into account the strain effect was in very good agreement with that obtained from the measurements.

Shubnikov-de Haas (S-dH) and Van der Pauw Hall effect measurements on strained In 0.15 Ga 0.85 As/Al 0.22 Ga 0.78 As single quantum well grown by molecular beam epitaxy have been performed to demonstrate the existence of the two-dimensional electron gas in the In 0.15 Ga 0.85 As single quantum well. The results of the fast Fourier transform results for the S-dH data clearly electron occupation of two subbands in the In 0.15 Ga 0.85 As single quantum well. Electronic subband energies and wavefunctions in the In 0.15 Ga 0.85 As quantum well were calculated by a self-consistent method taking into account exchange-correlation effects together without and with strain effects. The calculated total carrier density including the strain effect was in better agreements with that determined from the S-dH and Hall effect measurements.

Shubnikov - de Haas (SdH), Van der Pauw Hall effect and cyclotron resonance measurements on asymmetric double quantum wells grown by metalorganic chemical vapour deposition have been carried out to investigate the magnetotransport properties of an electron gas and to determine the effective mass of the electron gas, subband energies and wavefunctions in the quantum well. Transmission electron microscopy measurements show that a 50 A InAs and a 100 A quantum well were separated by a 30 A potential barrier in an active region. The SdH measurements at 1.5 K demonstrated clearly the existence of a quasi-two-dimensional electron gas (2DEG) in the quantum wells. The fast Fourier transformation results for the SdH data indicate clearly the electron occupation of two subbands in the double quantum wells. The results of the cyclotron resonance measurements show that one absorption resonance is evidence of electron concentration occupied at the ground state subband in the double quantum well. The electron effective mass determined from the slope of the main peak absorption energies as a function of a magnetic field is . Electronic subband energies and energy wavefunctions in the quantum wells were calculated by a self-consistent method taking into account exchange correlation effects together with strain and non-parabolicity effects. The ground state subband wavefunction is strongly localized in the InAs quantum well side, and the first excited subband wavefunction in the asymmetric quantum well is very weakly coupled over both InAs and wells.

Metal organic chemical vapour deposition of BaTiO3 using Ba(tmhd)2, Ti(OC3H7)4 and N2O, where tmhd equals 2,2,6,6-tetramethyl-3,5-heptanedionate, via pyrolysis at relatively low temperatures (∼370‡C) was performed in order to produce BaTiO3 insulator gates. Scanning electron microscopy showed that the surfaces of the BaTiO3 films had very smooth morphologies. Atomic force microscopy showed that the BaTiO3 thin film was polycrystalline. X-ray diffraction results indicated that BaTiO3 crystalline films grew on Si(100) with [110] orientation. High resolution transmission electron microscopy measurements showed that the BaTiO3 films were polycrystalline, and an interfacial layer in the BaTiO3/Si interface was formed. The stoichiometry and atomic structure of the BaTiO3 films were investigated by Auger electron spectroscopy and transmission measurements, respectively. Room temperature capacitance-voltage measurements clearly revealed metal-insulator-semiconductor behaviour for samples with BaTiO3 insulator gates, and interface state densities at the BaTiO3/p-Si interface were approximately high, 1011 eV−1 cm−2, at the middle of the Si energy gap.

Shubnikov-de Haas (S-dH) and Van der Pauw Hall-effect measurements on In 0.53 Ga 0.47 As In 0.52 Al 0.48 As and In 0.65 Ga 0.35 As In 052 Al 0.48 As one-side-modulation-doped quantum wells grown by metalorganic chemical vapor deposition have been carried out to investigate the magnetotransport properties of an electron gas and to determine the subband energies and wave functions in single quantum wells. Transmission electron microscopy measurements showed that the In 0.53 Ga 0.47 As In 0.52 Al 0.48 As heterointerfaces have a perfect lattice match and that the In 0.65 Ga 0.35 As In 0.52 Al 0.48 As heterointerfaces have a small lattice mismatch. The Shubnikov-de Haas measurements at 1.5 K demonstrated clearly the existence of a two-dimensional electron gas in the quantum wells. The fast Fourier transformation results for the S-dH data indicated clearly electron occupation of two and three subbands in the In0.53Ga0.47As and In0.65Ga0.35As single quantum wells, respectively. Electronic subband energies and wavefunctions in the quantum wells were calculated by a self-consistent method using the transfer matrix method based on the envelope-function approximation. These results indicate that the InxGa1−xAs quantum well with the smaller energy gap has more electron occupation in the subband levels.

Shubnikov-de Haas and Van der Pauw Hall effect measurements on a strained Al0.22Ga0.78As/In0.15Ga0.85As/GaAs one-side-modulation-doped quantum well grown by molecular beam epitaxy have been carried out to investigate the properties of an electron gas in a single quantum well. Transmission electron microscopy measurements showed that the Al 0.22 Ga 0.78 As In 0.15 Ga 0.85 As and In 0.15 Ga 0.85 As GaAs interfaces have no misfit dislocations. The results of the Shubnikov-de Haas measurements and the observation of the quantum Hall effect at 1.5 K clearly demonstrated the existence of a two-dimensional electron gas in the quantum well, and the fast Fourier transform results for the S-dH data clearly indicate electron occupation of two subbands in the In0.15Ga0.85As single quantum well. Electronic subband energies and wavefunctions in the In0.15Ga0.85As quantum well were calculated by a self-consistent method taking into account exchange-correlation effects.

A lattice-mismatched InP epitaxial layer on a GaAs(100) substrate was grown by the metal-organic chemical vapor deposition. Double-crystal X-ray diffraction was used to evaluate the crystallization and the crystal quality of the InP films. Transmission electron microscopy and Raman spectroscopy measurements showed that there was a lattice mismatch between the InP epitaxial layer and the GaAs substrate. The efficient photoluminescence measurements compared with those of InP homoepitaxy showed that high quality epitaxial films of InP could be grown on p-GaAs(100).

A new series of diarylureas and diarylamides possessing 1H-pyrrolo[3,2-c]pyridine scaffold was designed and synthesized. Their in vitro antiproliferative activities against A375P human melanoma cell line and NCI-9 human melanoma cell line panel were tested. All the target compounds, except three amino derivatives 8g, h and 9h, demonstrated superior potencies against A375P to Sorafenib. In addition, compounds 8a and 9b-f demonstrated higher potencies than Vemurafenib against A375P. Compounds 8c and 9b were 7.50 and 454.90 times, respectively, more selective towards A375P melanoma cells over NIH3T3 fibroblasts. Furthermore, compounds 8d, e and 9a-d, f demonstrated very high potencies against the nine tested melanoma cell lines at the NCI. The bisamide derivatives 9a-c, f showed 2-digit nanomolar IC(50) values over different cell lines of the NCI-9 melanoma cell lines.

Shubnikov-de Haas, Van der Pauw Hall-effect, and Raman spectroscopy measurements on In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As one-side-modulation-doped quantum wells grown by metalorganic chemical vapor deposition have been carried out to investigate the magnetotransport and optical properties of an electron gas in an In 0.53 Ga 0.47 As single quantum well. An electron diffraction pattern from transmission electron microscopy measurements shows that the In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As heterointerfaces have a perfect lattice match. The Shubnikov-de Haas and quantum Hall effect measurements at 1.5 K have demonstrated clearly the existence of a quasi-two-dimensional electron gas in the In 0.53 Ga 0.47 As quantum well. Raman spectroscopy shows the several optical phonon modes of the In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As structures, and indicates the interaction of the longitudinal optical phonons and the intersubband transitions.

Shubnikov-de Haas (SdH) and van der Pauw Hall effect measurements on In0.52Al0.48As/In0.53Ga0.47As/In0.52Al$ d0.48As one-side modulation-doped quantum wells grown by metalorganic chemical vapour deposition have been carried out to investigate the magnetotransport properties of an electron gas and to determine the subband energies and wavefunctions in a single quantum well. Transmission electron microscopy measurements show that the In0.53 Ga0.47As/In0.52Al0.48As heterointerfaces have a perfect lattice match. The SdH measurements at 1.5 K have demonstrated clearly the existence of a quasi-two-dimensional electron gas in the quantum well. The fast Fourier transformation results for the SdH data indicate clearly the occupation of two subbands in the In0.53Ga0.47As single quantum well. Electron energy subbands in the quantum well were calculated by a self-consistent method taking into account exchange-correlation effects and making use of the experimentally determined carrier density.

Diarylureas and diarylamides having a pyrrolopyridine scaffold are synthesized involving a nucleophilic displacement of the 4-chloro group of azaindole (I) by the aromatic amino group and a subsequent rearrangement of the resulting secondary amine to afford the key intermediates (III).

FMS is a type III receptor tyrosine kinase that binds to the macrophage or monocyte colony stimulating factor (M-CSF or CSF-1). Signal transduction through that binding results in survival, proliferation, and differentiation of monocyte/macrophage lineage. In this study, we report the discovery of a new potent inhibitor of FMS kinase. The synthesized pyrrolo[3,2-c]pyridine derivative (compound 1) was initially tested at a single concentration of 1 microM against 47 different kinases. At this concentration, the% inhibitions of the enzymatic activities of FMS and KDR kinases were 90% and 71%, respectively, while the inhibition in activity was less than 58% for all of the other kinases. For compound 1, the IC(50) values against FMS and KDR were 96 and 1058 nM, respectively. So, compound 1 was found to be 11 times more selective for FMS kinase than KDR kinase. Compound 1 can be used as a promising lead for the development of new selective inhibitors of FMS kinase, which can be used as useful therapeutic tools for treatment of several inflammatory and cancer disorders.

E-mail: choh@kist.re.krReceived August 20, 2008The synthesis of a new series of diaryl ureas having a pyrrolo[2,3-d]pyrimidine scaffold is reported here. Thein vitro antiproliferative activities of these diaryl derivatives against human melanoma cell line A375 weretested and the effect of substituents on the phenyl ring was investigated. The para substituted compounds Ia-gshowed superior or similiar activity to Sorafenib against the A375 cell line. Among these compounds, Ic-eshowed excellent activity against A375 compared with Sorafenib, a multi-kinase inhibitor.Key Words : Pyrrolo[2,3-d]pyrimidine, A375, Antiproliferative activityIntroductionMelanoma, the most aggressive form of skin cancer, is thefastest growing cancer in the United States.