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In the paper, a relationship of detectivity with material parameters is given by a theoretical calculation. An In 1− x Ga x As photovoltaic detector structure with x = 0.47 is used as an example for this study. The results show that the detectivity of a photodetector can be enhanced by optimizing the carrier concentration, thickness and surface recombination velocity during the structure growth and device fabrication.

Indirubin-3'-monoxime is a derivative of the bis-indole alkaloid indirubin, an active ingredient of a traditional Chinese medical preparation that exhibits anti-inflammatory and anti-leukemic activities. Indirubin-3'-monoxime is mainly recognized as an inhibitor of cyclin-dependent kinases (CDKs) and glycogen synthase kinase-3. It inhibits proliferation of cultured cells, mainly through arresting the cells in the G1/S or G2/M phase of the cell cycle. Here, we report that indirubin-3'-monoxime is able to inhibit proliferation of NIH/3T3 cells by specifically inhibiting autophosphorylation of fibroblast growth factor receptor 1 (FGFR1), blocking in this way the receptor-mediated cell signaling. Indirubin-3'-monoxime inhibits the activity of FGFR1 at a concentration lower than that required for inhibition of phosphorylation of CDK2 and retinoblastoma protein and cell proliferation stimulated by fetal calf serum. The ability of indirubin-3'-monoxime to inhibit FGFR1 signaling was similar to that of the FGFR1 inhibitor SU5402. In addition, we found that indirubin-3'-monoxime activates long-term p38 mitogen-activated protein kinase activity, which stimulates extracellular signal-regulated kinase 1/2 in a way unrelated to the activity of FGFR1. Furthermore, we show that indirubin-3'-monoxime can inhibit proliferation of the myeloid leukemia cell line KG-1a through inhibition of the activity of the FGFR1 tyrosine kinase. The data presented here demonstrate previously unknown activities of indirubin-3'-monoxime that may have clinical implications.

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are bioactive lipid mediators, which are known to play major roles in allergic reactions as well as in tumor pathogenesis. Here, the biological activities and signal pathways of these lysophospholipids (LPLs) in dendritic cells (DCs) were characterized further. Flow cytometric and immunoblot analyses indicate that immature as well as mature DCs express the LPL receptors S1P1, S1P3, S1P5, and LPA2, but not S1P2, S1P4, LPA1, or LPA3. Moreover, enzyme-linked immunosorbent assay experiments demonstrate that simultaneous addition of these LPLs to immature DCs in the presence of lipopolysaccharide enhanced the secretion of the inflammatory cytokines interleukin (IL)-6 and IL-8 in maturing DCs. In contrast, no modification of IL-6 or IL-8 release was observed after exposure of mature DCs to LPLs alone. In addition, studies with pertussis toxin and mitogen-activated protein kinase (MAPK) kinase inhibitor PD98059 suggested that Gi proteins and MAPK pathway are involved in these LPL-induced cell responses. Corroborating these findings, we observed that LPLs induce the phosphorylation of extracellular signal-regulated kinase 1/2 in immature DCs but not in mature DCs. Further analyses show that inhibitors of phosholipase D, Rho, and protein kinase C also inhibited the LPL-induced release of IL-6 and IL-8. Therefore, our findings suggest that lipopolysaccharide in DCs uncouples LPL receptors from the signal-transducing machinery during maturation and that exposure of LPLs at early time-points to maturing DCs modifies the proinflammatory capacity of mature DCs.

Natural killer (NK) cells perform multiple biological functions including tumor cell lysis and eradicating virally infected cells. Here, we report for the first time that D-galactosyl-beta1-1' sphingosine and D-glucosyl-beta1- 1' sphingosine damage human NK cells. We show that these cells express T-cell-associated gene-8, the receptor for glycosphingolipids. D-galactosyl-beta1-1' sphingosine and D-glucosyl-beta1-1' sphingosine induce the in vitro chemotaxis of human NK cells. Both D-galactosyl-beta1-1' sphingosine and D-glucosyl-beta1-1' sphingosine inhibit the cytotoxicity and IFN-gamma secretion by these cells. Further analysis shows that the glycosphingolipids D-galactosyl-beta1-1' sphingosine and D-glucosyl-beta1-1' sphingosine but not any other lipid examined, which include D-lactosyl-beta1-1' sphingosine, sphingosine 1-phosphate, sphingosine, lysophosphatidic acid, and phosphatidic acid, induce the apoptosis, globoid-like formation, and multinucleation in human NK cells. These results may have important implications on diseases where glycosphingolipids accumulate.

In this paper, the zero-bias resistance areas product R 0 A is calculated in the n + –n–p and p + –p–n Ga 0.8 In 0.2 As 0.81 Sb 0.19 infrared detectors, on the base of the material parameters in the three layers. The calculated results show that parameters in the heavily doped layer in the different structures have different influences on R 0 A . Moreover, R 0 A in the n + –n–p structure is higher than that in the p + –p–n structure because the higher carrier concentration in the n + -region for the n + –n–p structure improves R 0 A whereas the one in the p + -region for the p + –p–n structure reduces R 0 A .

A resonant-cavity-enhanced (RCE) PIN photodetector has high bandwidth and high sensitivity compared with traditional PIN photodetectors. In this paper, the structure of a RCE GaInAsSb/GaSb photodetector has been designed so that the light is incident from the substrate. The top reflector for this structure is made of 9.5–15.5 periods of InAs/GaSb quarter wave stacks (QWS) and the bottom reflector is composed of three periods of SiO2/Si QWS. An antireflection coating with more than 99% transmissivity is deposited on the substrate surface. A simulation shows that the quantum efficiency could be more than 90% at the operating wavelength 2.4 µm. The device has two spectral response peaks, which could make the device function as a double-colour detector.

Quantum dots (QDs), which capture and emit carriers like a giant trap, are studied using deep level transient spectroscopy (DLTS). The electrons and holes in the QDs are emitted from the relevant energy levels to the conduction and valence bands, respectively, of the barrier layers with increasing temperature. The thermal emission energies from the QDs are related to their initial energy levels. In this paper, five-period vertically stacked InAs QDs in the barrier layers of a field-effect type structure are measured. The results agree well with capacitance–voltage and photoluminescence measurements. In addition, the dependence of DLTS signal on the pulse voltage and light illumination is presented. The results prove that DLTS is a powerful tool for the study of the electronic structure of QDs.

In this paper, the detectivity is calculated and analyzed with the front-or backside illuminated case for both N-GaSb/p 2 -Ga 0.8 In 0.2 As 0.19 Sb 0.81 /p 1 -Ga 0.9 In 0.1 As 0.09 Sb 0.91 and N 1 -GaSb/n 2 -Ga 0.9 In 0.1 As 0.09 Sb 0.91 /p-Ga 0.8 In 0.2 As 0.19 Sb 0.81 infrared photovoltaic detectors, respectively. The analysis results show that the main absorption appears in the p-type Ga 0.8 In 0.2 As 0.19 Sb 0.81 material with either front- or backside illuminated case for above two structures. In each structure, the carrier concentration obviously affects the detectivity. The carrier concentration in the wide-bandgap material for the isotype heterojunction should be reduced as low as possible to reduce the tunneling rate at the isotype heterointerface. Moreover, the change of the detectivity with the p-side surface recombination velocity for the N 1 –n 2 –p structure is more sensitive than that with the p 1 -side surface recombination velocity for the N–p 2 –p 1 structure. In the N–p 2 –p 1 structure with the incident light from the p 1 -side surface, two-color detection is achieved.

A quantum dot (QD) can capture and emit carriers, the behavior of which is similar to that of a giant trap, and stacked QDs with a size-controlled growth show a strong tendency to align vertically. The discrete energy level properties of the self-assembled vertically stacked InAs QDs in Al0.5Ga0.5As are studied by means of deep level transient spectroscopy (DLTS) and photoluminescence (PL) spectroscopy. The DLTS measurement displays the spectra of hole and electron discrete energy levels as positive and negative peaks, respectively, which illustrates that the DLTS is a capable tool to study the optical and electrical properties of the QDs. The PL emission peaks are found to completely correspond to the DLTS signals.

Histamine is an important immunomodulator involved in allergic reactions and inflammatory responses. In endothelial cells, histamine induces Ca(2+) mobilization by releasing Ca(2+) from the endoplasmic reticulum and eliciting Ca(2+) entry across the plasma membrane. Herein, we show that histamine-evoked Ca(2+) entry in human umbilical vein endothelial cells (HUVECs) is sensitive to blockers of Ca(2+) release-activated Ca(2+) (CRAC) channels. RNA interference against STIM1 or Orai1, the activating subunit and the pore-forming subunit of CRAC channels, respectively, abolishes this histamine-evoked Ca(2+) entry. Furthermore, overexpression of dominant-negative CRAC channel subunits inhibits while co-expression of both STIM1 and Orai1 enhances histamine-induced Ca(2+) influx. Interestingly, gene silencing of STIM1 or Orai1 also interrupts the activation of calcineurin/nuclear factor of activated T-cells (NFAT) pathway and the production of interleukin 8 triggered by histamine in HUVECs. Collectively, these results suggest a central role of STIM1 and Orai1 in mediating Ca(2+) mobilization linked to inflammatory signaling of endothelial cells upon histamine stimulation.

There is an increasing need to quickly and efficiently learn network distances, in terms of metrics such as latency or bandwidth, between Internet hosts. For example, Internet content providers often place data and server mirrors throughout the Internet to improve access latency for clients, and it is necessary to direct clients to the nearest mirrors based on some distance metric in order to realize the benefit of the mirrors. We suggest a scalable Internet-wide architecture, called IDMaps, which measures and disseminates distance information on the global Internet. Higher level services can collect such distance information to build a virtual distance map of the Internet and estimate the distance between any pair of IP addresses. We present our solutions to the measurement server placement and distance map construction problems in IDMaps. We show that IDMaps can indeed provide useful distance estimations to applications such as nearest mirror selection.

In this paper, the detectivity as well as the quantum efficiency and the zero-bias resistance-area product in N-p and P-n GaSb/Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ infrared detectors is analyzed, based on the incident wavelength and the parameters of GaSb and Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/. The results show that the detectivity for the N-p structure is much higher than that for the P-n structure. In addition, the tunneling mechanism in both heterostructures strongly decreases the performance of Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81//GaSb detectors, The optimum detectivity is obtained when the zero-bias resistance-area product is limited by the generation-recombination mechanism. Furthermore, the detectivity in the N-p heterostructure is saturated with a small thickness of p-Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ while the one in the P-n heterostructure is maximum with thickness of n-Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ in the range of 2.5-3 /spl mu/m.

Catalyst-free InP nanowires were grown on Si (1 0 0) substrates by metal organic chemical vapor deposition. In this method, in situ deposited In droplets are seeds of the InP nanowires growth. In order to control the growth of epitaxial InP nanowires, a detailed investigation on the growth related aspects such as the In droplets deposition time, growth temperature, and V/III ratio has been made. The experimental results indicate that the diameter, shape, and length of the nanowires can be controlled by growth conditions.

In this paper, the detectivity for n+–n–p and p+–p–n GaInAsSb infrared detectors in both the front- and backside illuminated cases are calculated and analyzed, respectively. The influence of the carrier concentration and width in each layer, as well as the surface recombination velocities at different surfaces of the detectors are considered. It is indicated that high R0A dose not guarantee the high detectivity because the quantum efficiency combines with the R0A to determine the behavior of D*. On the base of the calculations, it is observed that the different material parameters are required for the optimum D* in the different structures with the different directions of the light injected.

In this paper, the performance is analyzed for the P 1 -p 2 -n and N 1 -n 2 -p hetero- and homojunction GaSb/Ga 0.8 In 0.2 As 0.19 Sb 0.81 photodetectors operated at 300 K, based on the incident wavelength and the parameters of GaSb and Ga 0.8 In 0.2 As 0.19 Sb 0.81 The analyzed results show that the detectivity is much higher with the light incident first through the p-type than first through the n-type Ga 0.8 In 0.2 As 0.19 Sb 0.81 for both structures. In addition, the carrier concentration of GaSb should be as low as possible to reduce the tunneling noise through the P 1 -p 2 and N 1 -n 2 heterojunctions. With the same condition for the two structures, the N 1 -n 2 -p structure is more advantage than the P 1 -p 2 -n structure because the high P 1 -p 2 heterojunction recombination velocity increases the Auger and radiative noise mechanisms, which limit the performance of photodetectors.

In this paper, the theoretical analysis of the Auger mechanism in n/sup +/-p GaInAsSb infrared photovoltaic detectors is reported. The lifetime caused by the Auger mechanism is calculated depending on the compositions, temperature, and carrier concentration. We also analyze the effect of material parameters on the detectivity of the n/sup +/-p GaInAsSb detectors. The calculated results show that the Auger mechanism could be suppressed by optimizing the material parameters, so that the performance of GaInAsSb infrared photovoltaic detectors is improved.

In this paper, a theoretical study of the effect of material parameters on the quantum efficiency of a homogeneous GaInAsSb infrared photovolatic detector is presented. The considerations are carried out for the near room temperature and 2.5 μ m wavelength. The calculated results show that the quantum efficiency depends strongly on the carrier concentrations in the n- and p-regions. In addition, the absorption coefficient, the surface recombination velocities and the widths of the two regions also effect the quantum efficiency.

An overgrowth InSb epilayer on GaAs substrate with large lattice-mismatch was grown by metalorganic chemical vapor deposition (MOCVD), and the heterogeneous crystalline state was observed by scanning electron acoustic microscopy (SEAM). The middle stage of relaxation of the large mismatch InSb/GaAs epilayer is observed by SEAM images of crystalline state of the buried subsurfaces. A macroscopical heterogeneous distribution is formed by large compression stress fields. It was a very important result to observe and study semiconductor epitaxial heterostructures by SEAM uniquely imaging mechanism.

In 0.82 Ga 0.18 As epilayers were grown by LP-MOCVD on InP (1 0 0) substrates with two-step growth method. It was analyzed that growth temperature of buffer layer exerted an influence on its crystalline quality and optical property, which were characterized by X-ray diffraction, scanning electron microscopy, and photoluminescence. The experiments showed that the crystalline quality and the optical property of the In 0.82 Ga 0.18 As epilayers had close relation to the growth temperature of buffer layer and the optimum buffer's growth temperature was about 450 °C.

In this paper a theoretical analysis of the product and the detectivity in a GaInAsSb infrared photovoltaic detector is reported, dependent on the four fundamental kinds of noise mechanism and the quantum efficiency. The considerations are carried out for near room temperature and m wavelength. The analytical results show that the noise mechanisms can be reduced, and correspondingly the performance of such detectors can be improved.

The In"0"."8"2Ga"0"."1"8As grown on InP (100) substrates by low pressure metalorganic chemical vapor deposition (LP-MOCVD) with two-step growth method was investigated. It was analyzed that the effect of In content of buffer layer on the crystalline quality and electrical property of the In"0"."8"2Ga"0"."1"8As eplialyers, which were characterized by X-ray diffraction, scanning electron microscopy, and Hall effect. The experiments show that the crystalline quality and the electrical property of the In"0"."8"2Ga"0"."1"8As eplialyers have close relation to the In content of buffer layer and will be optimum when the In content of buffer layer is same as that of the epilayer.

MOCVD growth and characterization of InAs-rich GaInAsSb on GaSb substrates was investigated. High quality mirror-like surfaces with a minimum lattice mismatch of 0.4% was obtained. The surface of InAs-rich GaInAsSb epilayer shows morphological features much different from that of GaSb-rich films. Solid compositions of InAs-rich films were dependent on growth temperature. InAs-rich GaInAsSb shows n-type conduction, which is the opposite of GaSb-rich samples. A room temperature electron mobility of 5000 cm(2)/V.s with electron concentration of 3.6 x 10(17) cm(-3) was obtained. (C) 1998 Elsevier Science B.V. All rights reserved.

MOCVD growth and characterization of GaSb-rich and InAs-rich GaInAsSb on GaSb substrates was investigated. The surface of InAs-rich GaInAsSb epilayers showed morphological features very different from those on GaSb-rich films. Solid compositions of Ga1-xInxAsySb1-y films were dependent on growth temperature and the input source ratios, such as Ga/III ratio and Sb/V ratio. Unintentionally doped InAs-rich GaInAsSb showed n-type conduction, and GaSb-rich samples were p-type. A room temperature electron mobility of 5000 cm2v-1s-1 with electron concentration of 3.6×1017cm-3 for InAs-rich films was obtained. On the other hand, a hole mobility of 360 cm2v-1s-1 with a hole concentration of 1×1017cm-3 for GaSb-rich samples was achieved. © 1998 Chapman & Hall

InSb epilayers were grown on GaAs substrates by atmospheric pressure metalorganic chemical vapor deposition (MOCVD). The surface and subsurface morphologies of InSb epilayers were observed by scanning electron microscopy (SEM) and scanning electron acoustic microscopy (SEAM), and the crystalline properties were characterized by the single-crystal X-ray diffraction pattern and double-crystal X-ray rocking curve. Two types of crystalline state after the release of the large compression stress, one was homogeneous dislocation array and the other was heterogeneous plastic flow, were observed and discussed. © 1997 Elsevier Science S.A. All rights reserved.

The quaternary Ga 0.16 In 0.84 As 0.80 Sb 0.20 epilayer was grown on GaSb substrate by metalorganic chemical vapour deposition (MOCVD). On the epitaxial surface smooth and perfect three-dimensional islands were observed by atomic force microscopy (AFM). A good crystalline quality was characterized by single-crystal X-ray diffraction pattern and double-crystal X-ray rocking curve. When the growth rate of the growth nucleus is larger than the growth rate of the high-index facet, the mode of island growth is isotropic.

Patterned carbon nanotubes on silicon substrates were obtained using electrophoretic method. The carbon nanotubes migrated towards the patterned silicon electrode in the electrophoresis suspension under the applied voltage. The carbon nanotubes arrays adhered well on the silicon substrates. The surface images of carbon nanotubes were observed by scanning electron microscopy. The field emission properties of the patterned carbon nanotubes were tested in a diode structure under a vacuum pressure below 5 × 10 −4 Pa. The measured emission area was about 1.0 mm 2 . The emission current density up to 30 mA/cm 2 at an electric field of 8 V/μm has been obtained. The deposition of patterned carbon nanotubes by electrophoresis is an alternative method to prepare field emission arrays.

In this paper, the electron emission from a cathode with a large number of emission sites is discussed by introducing a distribution function of the field enhancement factor β. After accounting for the distribution of the field enhancement factor, the field electron emission from the cathode deviates from the classical Fowler–Nordheim (F–N) theory, the F–N plot is not a straight line and bends up in region of low electric field. A good agreement of the calculated results with experimental results was achieved by employing a reasonable distribution function of β.

Cdc42 is a Ras-related GTPase that plays an important role in the regulation of a range of cellular functions, including cell migration, proliferation, and survival. Consistent with its critical functions in vitro, the inactivation of Cdc42 in mice has been shown to result in embryonic lethality at embryonic day 6.5 (E6.5) before blood vessel formation. To determine the role of Cdc42 in new blood vessel formation, we have generated vascular endothelial cell (EC)-specific Cdc42 knockout mice by crossing Cdc42(flox/flox) mice with Tie2-Cre mice. The deletion of Cdc42 in ECs caused embryonic lethality with vasculogenesis and angiogenesis defects. We observed that Cdc42 is critical for EC migration and survival but not for cell cycle progression. Moreover, we found that the inactivation of Cdc42 in ECs decreased the level of vascular endothelial growth factor receptor 2 (VEGFR2) protein on the EC surface and promoted the production of a 75-kDa membrane-associated C-terminal VEGFR2 fragment. Using cultured primary mouse ECs and human umbilical vein ECs, we have demonstrated that the deletion of Cdc42 increased ADAM17-mediated VEGFR2 shedding. Notably, inhibition of ADAM17 or overexpression of VEGFR2 can partially reverse Cdc42 deletion-induced EC apoptosis. These data indicate that Cdc42 is essential for VEGFR2-mediated signal transduction in blood vessel formation.

Fibroblast growth factor 1 (FGF1) controls cellular activities through the activation of specific cell-surface FGF receptors (FGFRs). Transphosphorylation of tyrosine residues in the kinase domain of FGFRs leads to activation of intracellular signaling cascades, including those mediated by mitogen-activated protein kinases (MAPKs). FGFRs also contain a serine-rich C-terminal tail. We identified a regulatory mechanism of FGFR signaling involving phosphorylation of Ser(777) in the C-terminal region of FGFR1 by the MAPKs extracellular signal-regulated kinase 1 (ERK1) and ERK2. Prevention of the phosphorylation of Ser(777) in FGFR1 or mutation of Ser(777) to alanine enhanced FGF-stimulated receptor tyrosine phosphorylation and increased cell proliferation, cell migration, and axonal growth. A form of FGFR1 with a phosphomimetic mutation at Ser(777) exhibited reduced signaling. Activation of MAPKs by other receptor tyrosine kinases also resulted in phosphorylation of Ser(777) in FGFR1, thereby enabling crosstalk regulation of FGFR activity by other signaling pathways. Our data reveal a negative feedback mechanism that controls FGF signaling and thereby protects the cell from excessive activation of FGFR.

The capability of scanning electron acoustic microscopy in semiconductor materials has been studied. The signal generation mechanisms and applications of scanning electron acoustic microscopy in n-GaSb (Te-doped) crystals, and GaInAsSb on GaSb, GaSb on GaAs and InSb epilayer on a GaAs substrate are investigated, which shows the new technique for image and characterization of thermal, elastic and pyroelectric property variations on a microscale resolution.

The establishment of a polarized cellular morphology is essential for a variety of processes including neural tube morphogenesis and the development of the brain. Cdc42 is a Ras-related GTPase that plays an essential role in controlling cell polarity through the regulation of the actin and microtubule cytoskeleton architecture. Previous studies have shown that Cdc42 plays an indispensable role in telencephalon development in earlier embryo developmental stage (before E12.5). However, the functions of Cdc42 in other parts of brain in later embryo developmental stage or in adult brain remain unclear. Thus, in order to address the role of Cdc42 in the whole brain in later embryo developmental stage or in adulthood, we used Cre/loxP technology to generate two lines of tissue-specific Cdc42-knock-out mice. Inactivation of Cdc42 was achieved in neuroepithelial cells by crossing Cdc42/ flox mice with Nestin-Cre mice and resulted in hydrocephalus, causing death to occur within the postnatal stage. Histological analyses of the brains from these mice showed that ependymal cell differentiation was disrupted, resulting in aqueductal stenosis. Deletion of Cdc42 in the cerebral cortex also induced obvious defects in interkinetic nuclear migration and hypoplasia. To further explore the role of Cdc42 in adult mice brain, we examined the effects of knocking-out Cdc42 in radial glial cells by crossing Cdc42/flox mice with human glial fibrillary acidic protein (GFAP)-Cre mice. Inactivation of Cdc42 in radial glial cells resulted in hydrocephalus and ependymal cell denudation. Taken together, these results highlight the importance of Cdc42 for ependymal cell differentiation and maintaining, and suggest that these functions likely contribute to the essential roles played by Cdc42 in the development of the brain.

GaInAsSb alloys were grown by atmospheric pressure metalorganic chemical vapour deposition (MOCVD) on n-GaSb (Te-doped) substrates, oriented 2°–3° off (100) towards 〈110〉. The surface morphology of Sb-related III–V compounds depends on the growth parameters, the lattice mismatch and the quality and orientation of the surface of the substrate. The defect growth process is observed by scanning electron microscopy (SEM) and scanning electron acoustic microscopy (SEAM). The Ga and Sb concentrations in the solid were characterized as a function of the input ratio of Sb to group V, the AsH3 molar flow rate and growth temperature. On the other hand, the growth efficiency has been studied versus the AsH3 molar flow and growth temperature. The crystalline quality of the GaInAsSb epilayer has been characterized by the single-crystal X-ray diffraction pattern and double-crystal X-ray rocking curve diffraction.

Metalorganic chemical vapor deposition (MOCVD) of ternary GaxIn1−xSb alloys on GaSb and GaAs substrates has been investigated at atmospheric pressure, using TMGa, TMIn and TMSb as source materials. The optimized growth parameters obtained by experiment were a growth temperature of 600°C and a vapor IIIV ratio of 0.4. It was found that the growth temperature was a key growth parameter for surface morphology and crystalline quality of the GaxIn1−xSb epilayer. The influence of the growth temperature on the Ga solid composition was previously explained. The Ga solid composition was proportional to the Ga vapor composition and vapor IIIV ratio, respectively. The Ga distribution coefficient was found to be 1.06 under the optimized growth parameters and decreased with decreasing growth temperature. The results of the Hall measurement for GaxIn1−xSb alloys were presented with p-type background of the epilayers.

The formation of blood vessel networks is a fundamental event in vertebrate embryo development. Angiogenesis and vasculogenesis are the essential processes in vascular formation. Endothelial cells play a key role during angiogenesis and vasculogenesis, and cultured vascular endothelial cells provide an indispensable model for exploring the molecular mechanisms of angiogenesis and vasculogenesis. In this chapter, we described a protocol using PECAM-1-coated Dynabeads for the isolation of vascular endothelial cells from mouse heart and lung. This method will provide up to 10(7) endothelial cells with high purity (85%). The isolated endothelial cells retain their in vivo characteristics, such as the expression of the cell surface markers PECAM-1 and ICAM-2.

The formation of blood vessel networks is a fundamental event in vertebrate embryo development. Angiogenesis and vasculogenesis are the essential processes in vascular formation. Endothelial cells play a key role during angiogenesis and vasculogenesis, and cultured vascular endothelial cells provide an indispensable model for exploring the molecular mechanisms of angiogenesis and vasculogenesis. In this chapter, we described a protocol using PECAM-1-coated Dynabeads for the isolation of vascular endothelial cells from mouse heart and lung. This method will provide up to 10(7) endothelial cells with high purity (>85%). The isolated endothelial cells retain their in vivo characteristics, such as the expression of the cell surface markers PECAM-1 and ICAM-2.

Fibroblast growth factor 1 (FGF1) taken up by cells into endocytic vesicles can be translocated across vesicular membranes into the cytosol and the nucleus where it has a growth regulatory activity. Previously, leucine-rich repeat containing 59 (LRRC59) was identified as an intracellular binding partner of FGF1, but its biological role remained unknown. Here, we show that LRRC59 is strictly required for nuclear import of exogenous FGF1. siRNA-mediated depletion of LRRC59 did not inhibit the translocation of FGF1 into cytosol, but blocked the nuclear import of FGF1. We also found that an nuclear localization sequence (NLS) in FGF1, Ran GTPase, karyopherin-α1 (Kpnα1), and Kpnβ1 were required for nuclear import of FGF1. Nuclear import of exogenous FGF2, which depends on CEP57/Translokin, was independent of LRRC59, but was dependent on Kpnα1 and Kpnβ1, while the nuclear import of FGF1 was independent of CEP57. LRRC59 is a membrane-anchored protein that localizes to the endoplasmic reticulum (ER) and the nuclear envelope (NE). We found that LRRC59 possesses NLS-like sequences in its cytosolic part that can mediate nuclear import of soluble LRRC59 variants, and that the localization of LRRC59 to the NE depends on Kpnβ1. We propose that LRRC59 facilitates transport of cytosolic FGF1 through nuclear pores by interaction with Kpns and movement of LRRC59 along the ER and NE membranes.

The KG-1a cell line is developed from a human stem cell myeloproliferative neoplasm as the result of intragenic disruption and a chromosomal translocation of the FGFR1 gene and the FGFR1OP2 gene encoding a protein of unknown function called FOP2 (FGFR1 Oncogene Partner 2). The resulting fusion protein FOP2-FGFR1 is soluble and has constitutive tyrosine kinase activity. Since the heat shock protein HSP90 and its co-chaperone CDC37 have been shown to stabilize many oncogenic proteins, we investigated the requirement for HSP90 or HSP90-CDC37 assistance to maintain the stability or activity of FOP2-FGFR1 expressed in KG-1a cells. We found that HSP90-CDC37 forms a permanent complex with FOP2-FGFR1. This results in protection against degradation of FOP2-FGFR1 and holds the oncoprotein in a permanently active conformation. Inhibition of HSP90 or depletion of CDC37 or heat shock factor 1 (HSF1) reduced the expression level of FOP2-FGFR1 and was sufficient to block the oncoprotein induced proliferation of KG-1a cells. We conclude that the driver of malignancy in KG-1a leukemic cells, FOP2-FGFR1, is an HSP90 addicted oncoprotein. This provides a rationale for the therapeutic use of HSP90 inhibitors in myeloid leukemias that contain FGFR fusion proteins.

Planar-gate type carbon nanotubes field emission electron sources were fabricated with special electrophoretic method. The simulation and experiment results showed electron emission from the nanotubes could be controlled effectively by the gate voltage. The easy fabrication process and simple structure will lead to the electron sources used in many practical vacuum microelectron devices

The phosphorylcholine-containing lipid lysophosphatidylcholine (LPC) is abundant in the bloodstream, whereas sphingosylphosphorylcholine (SPC) and platelet-activating factor (PAF) highly accumulate at inflamed sites. Utilizing RT-PCR, flow cytometry and immunoblot analyses, we show for the first time that ovarian cancer G protein-coupled receptor 1, the receptor for SPC, is expressed in IL-2-, IL-12- and IL-15-activated but not in resting CD16-, resting CD16+ or IFN-alpha-activated NK cells. Similarly, G2 accumulation and PAF receptor are variably expressed in these subsets of NK cells. SPC, LPC and PAF differentially induce the chemotaxis of resting and activated NK cells. In the chemotaxis assay, it is observed that resting CD16-CD56bright and CD16+CD56dim cells predominantly respond to LPC, whereas activated NK cells, regardless of the sort of stimulus, robustly respond to PAF. SPC is also a potent chemoattractant for IL-2-, IL-12- and IL-15- but not for IFN-alpha-activated NK cells. Further analysis shows that, depending on the cytokine pattern of NK cell activation, phosphorylcholine-containing lipids differentially affect IFN-gamma secretion by these cells. Our results provide one possible explanation for the tissue compartmentation of NK cells and their ability to secrete IFN-gamma. Furthermore, these results may provide novel information regarding NK cell regulation during inflammation.

Multi-wall carbon nanotubes were deposited on the patterned silicon substrates using electrophoretic deposition. The surface images of carbon nanotubes on substrate were observed by scanning electron microscopy. Field emission properties have been tested with a diode structure in a vacuum chamber below 5/spl times/10/sup -4/ Pa. The emission area measured is 1.0mm. Emission current density up to 30mA/cm at an electric field of 8V//spl mu/m has been obtained. Patterned deposition of carbon nanotubes by electrophoresis is a potential method to prepare field emission arrays.

Scanning electron acoustic microscopy (SEAM) is a new experimental tool. SEAM study has been performed on GaInAsSb epilayer, which was grown upon 2°-off (1 0 0) towards 〈1 1 0〉 GaSb substrate by metalorganic chemical vapour deposition (MOCVD). Comparison of scanning electron microscopy (SEM) and SEAM images show that the two techniques provide different information. SEAM images can give information on growth process of pyramidal hillocks during the deposition of GaInAsSb epilayer.

Dendritic cells (DCs) generated by a single-step exposure of human monocytes to type I IFN and GM-CSF (IFN-DCs) are endowed with potent immunostimulatory activities and a distinctive migratory response to specific chemokines. In this study, we evaluated the effects of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active metabolite of vitamin D3, on the DC differentiation/activation induced by type I IFN. We found that 1,25(OH)2D3 prevented the generation of IFN-DCs when added to freshly isolated monocytes, and was capable of redirecting already differentiated IFN-DCs toward a more immature stage, as revealed by their immunophenotype, reduced allostimulatory activity, and impaired LPS-induced production of Th1-polarizing cytokines. Control and 1,25(OH)2D3-treated IFN-DCs exhibited a similar expression of vitamin D receptor, as well as comparable cell death rates. Furthermore, the chemotactic response of IFN-DCs to CCL4 and CCL19 was markedly reduced or completely abrogated by 1,25(OH)2D3. Despite these changes in the IFN-DC migratory behavior, the expression of CCR5 and CCR7 and the calcium fluxes triggered by CCL4 and CCL19 were not affected. These findings indicate that, in this innovative single-step DC generation model from monocytes, the suppressive effect of 1,25(OH)2D3 is associated with a potent impairment of DC migration in response to inflammatory and lymph node-homing chemokines, thus unraveling a novel mechanism involved in 1,25(OH)2D3-mediated immunomodulation.

The Internet distance map service (IDMaps) [P. Francis, S. Jamin, C. Jin, D. Raz, Y. Shavitt, and L. Zhang, 2001] provides distance estimates between any pair of hosts connected to the Internet. The IDMaps system comprises two component types: tracers that measure distance between IP address prefixes, and servers that collect measurement results and answer distance queries. The distance information protocol (DIP) is used for tracers to report measured distance data to servers. The dynamics on the Internet topology, the distributed nature of autonomous tracers and servers, and the vast size of the data set require that DIP provide highly adaptive and scalable data dissemination from tracers to servers. DIP is a soft-state announce/listen protocol and scales independently from the total amount of measurement data by all tracers. DIP achieves its scalability through combination of staged timers, positive feedback, and feedback suppression techniques, which enable DIP to disseminate only the most useful measurement data to servers in a dynamic way. Simulations verified DIP's scalability and adaptability under various network conditions.

Platelet factor four (PF4), an inhibitor of endothelial cell proliferation in vitro, inhibits angiogenesis and tumor growth in vivo in experimental animals. The present study was designed to determine whether gene therapy-mediated expression of a form of PF4 lacking 16 amino acids of N-terminus from tumor cells could inhibit angiogenesis and tumor growth in vivo. Two replication-defective recombinant retroviral vectors were constructed. One encodes human PF4 (rRV-PF4) and the other encodes the N-truncated peptide (rRVp17-70). These vectors were then used to transduce KB cells, a human head and neck squamous carcinoma cell line. Expression of PF4 and p17-70 transgenes was confirmed by Western blot analysis. In vitro, both rRV-PF4 and rRVp17-70 were able to inhibit selectively the proliferation of human umbilical vascular endothelial cells (HUVEC) but not KB cells. In vivo activity was assessed by injecting 10(7) KB cells subcutaneously into nude mice and by monitoring subsequent tumor growth, xenograft vascular histochemistry, and animal survival. Viral vector-mediated cDNA transfer of PF4 and p17-70 resulted in inhibiting solid tumors through an anti-angiogenic action in vivo. Our data indicate that targeting tumor angiogenesis using viral-mediated gene transfer of full-length and N-terminal truncated PF4 represents a promising strategy for cancer gene therapy.

We demonstrate the expression of S1P(1,3,4,5) the receptors for sphingosine 1-phosphate (S1P), and LPA(1,2,3) the receptors for lysophosphatidic acid (LPA) in T helper 1 (Th1) and T helper 2 (Th2) cells. S1P and LPA induce the chemotaxis of Th1 and Th2 cells, an activity that is resistant to pertussis toxin (PTX) pretreatment in Th1, but is sensitive in Th2 cells. Also, I-TAC-induced Th1 and eotaxin-induced Th2 cell chemotaxis are blocked by PTX pretreatment. LPA but not S1P induces calcium flux response in Th1 and Th2 cells, which is due to the influx of extracellular calcium and is mediated by receptor activation, since EGTA and suramin (SUR) completely abrogate LPA-induced the release of calcium. No cross-desensitization is observed between thapsigargin (TG) and LPA in both cell types. PTX and SUR but not EGTA inhibit I-TAC- or eotaxin-induced [Ca(2+)](i) release in Th1 and Th2 cells. Our results indicate that lysophospholipids and chemokines stimulate different signal transduction pathways.

The InxGa1-xAs/InP was grown by low-pressure metalorganic chemical vapor deposition (LPMOCVD). We used Raman spectroscopy to characterize the quality of epilayers and measure the strain. Raman spectra from InxGa1-xAs epitaxial layers of various compositions were studied. Raman spectra were obtained at 300K, 248K, 193K, 138K, and 80K. The difference in the frequencies of their GaAs-like LO phonons was to calculate stress for the InGaAs/InP, leading to direct formula for the evaluation of the epilayer stress.

Field emission from a polycrystalline diamond film was observed at as low as the gate voltage of 10 V by evaporation of an ultra thin metal film on diamond films as gate, and the emission image observed on a fluorescent screen shows that the electrons are emitted uniformly from the cathode area. The emission mechanisms of field emission from diamond was discussed and suggested the electron emission may be occurred from boundaries of diamond grains.

Vertically stacked QD growth in precision can be incorporated to develop new structures and improve the size and spatial distribution ofthe strain-induced QD ensemble. Photoluminescence (PL) ofquantum dots embedded in high potential barriers is studied as functions ofbarrier thickness, temperature, and laser excitation power. With the increase of un-doped barrier thickness, both of strengthened two-dimensional electron gas (2DEG) structure and strongly localized electron wave functions can increase the carrier recombination. The optical properties of different-barrier-thickness samples exhibit different characteristics with the decreased measurement temperatures. The PL recombination characteristic of the samples with the barriers adjacent to a Si-doping GaAs layer is different from that of samples with barrier adjacent to an i-GaAs layer.