Development of a PVDF Sensor Array for Measurement of the Dynamic Pressure Field of the Blade Tip in an Axial Flow Compressor.

Tip clearance flow in axial flow compressor is unavoidable and responsible for pressure losses and noise generation and influences the stability of the compressor. However, necessary flow measurement in the blade tip region is a great challenge due to the small gap width as well as the structure limitation. In this paper, a polyvinylidene fluoride (PVDF) piezoelectric-film sensor array is developed to capture the dynamic pressure field over the blade tip in an axial flow compressor. The PVDF sensor array with 40 evenly distributed sensing points is fabricated directly on a 30 µm thick aluminum-metalized polarized PVDF film through photolithography. Dynamic calibration of the sensor is accomplished using acoustic source as excitation and a microphone as a reference. The test pressure range is up to 3.5 kPa and the sampling frequency is 20 kHz. The sensor presents a high signal-to-noise ratio and good consistency with the reference microphone. Sensitivity, frequency response, linearity, hysteresis, repeatability as well as the influence of temperature are also investigated through the calibration apparatus. The calibration gives credence to the relevance and reliability of this sensor for the application in dynamic pressure field measurement. The sensor is then applied to an actual measurement in a compressor. The output of the PVDF sensor array is also compared with the results of common pressure transducers, and the features of the dynamic pressure filed are discussed. The results indicate that the PVDF sensor array is capable of the dynamic pressure field measurement over the blade tip, and superior to the conventional approaches in installation, spatial resolution, frequency response, and cost. These advantages indicate its potential broad application in pressure measurement, especially for the complex spatial surface or thin-walled structure, such as the blade surface and the thin casing wall of the compressor.

ErbB3 Ligand Heregulin1 Is a Major Mitogenic Factor for Uncontrolled Lung Cancer Cell Proliferation.

There are seven ligands for the epidermal growth factor receptor (EGFR) ErbB1 and two ligands for ErbB3. EGFR can form a homodimer or a heterodimer with ErbB3. In this study, we investigated whether homodimers or heterodimers, and which ligand, play a major role in cancer development, with the goal of ultimately identifying therapeutic targets. We demonstrated that the ErbB3 ligand heregulin1 is the strongest mitogenic factor for non-small cell lung cancer cells and is more potent in activating EGFRmut-ErbB3 heterodimers than EGFRwt-ErbB3 heterodimers. We discovered that four of the seven EGFR ligands inhibited heregulin1-induced EGFRwt-ErbB3 activation and cell proliferation by promoting dephosphorylation of heregulin1-induced ErbB3 phosphorylation, whereas the other three did not exhibit such inhibition. Importantly, those four EGFR ligands did not inhibit heregulin1-induced EGFRmut-ErbB3 activation and proliferation of cells with EGFR mutants. We demonstrated that ErbB3 was overexpressed in the lung cancer cells but not in the adjacent normal alveoli or stromal tissue. EGFR and heregulin1 were also highly expressed in lung cancer cells. We conclude that the overexpression of heregulin1, ErbB3, and EGFR mutant renders uncontrolled cell proliferation.

Combined ultrasound with Fenton treatment for the degradation of carcinogenic polycyclic aromatic hydrocarbons in textile dying sludge.

To develop an effective method to remove the toxic and carcinogenic polycyclic aromatic hydrocarbons (CPAHs) from textile dyeing sludge, five CPAHs were selected to investigate the degradation efficiencies using ultrasound combined with Fenton process (US/Fenton). The results showed that the synergistic effect of the US/Fenton process on the degradation of CPAHs in textile dyeing sludge was significant with the synergy degree of 30.4. During the US/Fenton process, low ultrasonic density showed significant advantage in degrading the CPAHs in textile dyeing sludge. Key reaction parameters on CPAHs degradation were optimized by the central composite design as followed: H2O2 concentration of 152 mmol/L, ultrasonic density of 408 W/L, pH value of 3.7, the molar ratio of H2O2 to Fe2+ of 1.3 and reaction time of 43 min. Under the optimal conditions of the US/Fenton process, the degradation efficiencies of five CPAHs were obtained as 81.23% (benzo[a]pyrene) to 84.98% (benz[a]anthracene), and the benzo[a]pyrene equivalent (BaPeq) concentrations of five CPAHs declined by 81.22-85.19%, which indicated the high potency of US/Fenton process for removing toxic CPAHs from textile dyeing sludge.

A network-based predictive gene-expression signature for adjuvant chemotherapy benefit in stage II colorectal cancer.

BACKGROUND: The clinical benefit of adjuvant chemotherapy for stage II colorectal cancer (CRC) is controversial. This study aimed to explore novel gene signature to predict outcome benefit of postoperative 5-Fu-based therapy in stage II CRC. METHODS: Gene-expression profiles of stage II CRCs from two datasets with 5-Fu-based adjuvant chemotherapy (training dataset, n = 212; validation dataset, n = 85) were analyzed to identify the indicator. A systemic approach by integrating gene-expression and protein-protein interaction (PPI) network was implemented to develop the predictive signature. Kaplan-Meier curves and Cox proportional hazards model were used to determine the survival benefit of adjuvant chemotherapy. Experiments with shRNA knock-down were carried out to confirm the signature identified in this study. RESULTS: In the training dataset, we identified 44 PPI sub-modules, by which we separate patients into two clusters (1 and 2) having different chemotherapeutic benefit. A predictor of 11 PPI sub-modules (11-PPI-Mod) was established to discriminate the two sub-groups, with an overall accuracy of 90.1%. This signature was independently validated in an external validation dataset. Kaplan-Meier curves showed an improved outcome for patients who received adjuvant chemotherapy in Cluster 1 sub-group, but even worse survival for those in Cluster 2 sub-group. Similar results were found in both the training and the validation dataset. Multivariate Cox regression revealed an interaction effect between 11-PPI-Mod signature and adjuvant therapy treatment in the training dataset (RFS, p = 0.007; OS, p = 0.006) and the validation dataset (RFS, p = 0.002). From the signature, we found that PTGES gene was up-regulated in CRC cells which were more resistant to 5-Fu. Knock-down of PTGES indicated a growth inhibition and up-regulation of apoptotic markers induced by 5-Fu in CRC cells. CONCLUSIONS: Only a small proportion of stage II CRC patients could benefit from adjuvant therapy. The 11-PPI-Mod as a potential predictor could be helpful to distinguish this sub-group with favorable outcome.

Degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge with ultrasound and Fenton processes: Effect of system parameters and synergistic effect study.

To establish an efficient oxidation process for the degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge, the effects of various operating parameters were optimized during the ultrasound process, Fenton process and the combined ultrasound-Fenton process. The results showed that the ultrasonic density of 1.80w/cm(3), both H2O2 and Fe(2+) dosages of 140mmol/L and pH 3 were favorable conditions for the degradation of PAHs. The degradation efficiency of high molecular weight PAHs was close to or even higher than that of light molecular weight PAHs. The highest degradation efficiencies of Σ16 PAHs were obtained within 30min in the order of: Fenton (83.5%) >ultrasound-Fenton (75.5%) >ultrasound (45.5%), then the efficiencies were decreased in the other of: ultrasound-Fenton (73.0%) >Fenton (70.3%) >ultrasound (41.4%) in 60min. The extra PAHs were released from the intracellular substances and the cavities of sludge due to the disruption of sludge during the oxidation process. Also, the degradation of PAHs could be inhibited by the other organic matter in the sludge. The combined ultrasound-Fenton process showed more efficient than both ultrasound process and Fenton process not only in the surface of sludge but also in the sludge interior.

Effect of K2FeO4/US treatment on textile dyeing sludge disintegration and dewaterability.

The effect of potassium ferrate/ultrasonic (K2FeO4/US) treatment on the physicochemical features of textile dyeing sludge was studied. The soluble chemical oxygen demand (SCOD), deoxyribonucleic acid (DNA), sludge volume index (SVI), sludge viscosity, capillary suction time (CST) and particle size were measured to understand the observed changes in the sludge physicochemical features. The results showed that the combined K2FeO4/US treatment presented great advantages for disrupting the sludge floc structure over K2FeO4 or ultrasonic treatments alone. The optimal parameters of sludge disintegration were found to be a K2FeO4 treatment time of 60 min, a K2FeO4 dosage of 0.5936 g/g SS, an ultrasonic time of 15 min and an ultrasonic intensity of 0.72 W/mL. The initial median diameter of the sludge particles was 15.24 µm, and this value decreased by 35.89%. The CST was initially 59.6 s and increased by 231%, whereas the SVI was 97.78 mL/g and decreased by 25.89%. Scanning electron microscope (SEM) images indicated that the sludge surface was irregular and loose with a large amount of channels or voids during K2FeO4/US treatment. K2FeO4/US treatment synergistically enhanced the sludge solubilization and reached 668.67 mg/L SCOD, which is 31.81% greater than the additive value obtained with K2FeO4 treatment alone (215.95 mg/L) or with ultrasonic treatment alone (240 mg/L).

Fate of volatile aromatic hydrocarbons in the wastewater from six textile dyeing wastewater treatment plants.

The occurrence and removal of benzene, toluene, ethylbenzene, xylenes, styrene and isopropylbenzene (BTEXSI) from 6 textile dyeing wastewater treatment plants (TDWTPs) were investigated in this study. The practical capacities of the 6 representative plants, which used the activated sludge process, ranged from 1200 to 26000 m(3) d(-1). The results indicated that BTEXSI were ubiquitous in the raw textile dyeing wastewater, except for isopropylbenzene, and that toluene and xylenes were predominant in raw wastewaters (RWs). TDWTP-E was selected to study the residual BTEXSI at different stages. The total BTEXSI reduction on the aerobic process of TDWTP-E accounted for 82.2% of the entire process. The total BTEXSI concentrations from the final effluents (FEs) were observed to be below 1 µg L(-1), except for TDWTP-F (2.12 µg L(-1)). Volatilization and biodegradation rather than sludge sorption contributed significantly to BTEXSI removal in the treatment system. BTEXSI were not found to be the main contaminants in textile dyeing wastewater.

Differential disruption of EWS-FLI1 binding by DNA-binding agents.

Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin D preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin D globally repressed transcription. These results demonstrate that actinomycin D preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors.

Shikonin, a natural product from the root of Lithospermum erythrorhizon, is a cytotoxic DNA-binding agent.

To search for compounds that disrupt binding of the EWS-FLI1 fusion protein to its cognate targets, we developed a homogeneous high-throughput proximity assay and screened 5200 small molecule compounds. Many well-known DNA-binding chemotherapeutic agents, such as actinomycin D, cisplatin, doxorubicin, daunorubicin, and epirubicin scored in the assay and not surprising also disrupted the binding of other transcription factors. Unexpectedly, we found that Shikonin, a natural product from the root of Lithospermum erythrorhizon, similarly disrupted protein-DNA interactions. Mechanistic studies demonstrated that Shikonin displaces SYBR green from binding to the minor groove of DNA and is able to inhibit topoisomerase mediated DNA relaxation. In cells, Shikonin blocked the binding of EWS-FLI1 to the NR0B1 promoter, and attenuated gene expression. Shikonin rapidly induced G2/M arrest and apoptosis in Ewing sarcoma cells. These results demonstrate that contrary to other purported mechanisms of action, Shikonin is a DNA-binding cytotoxic agent.

Anti-inflammatory properties of histone deacetylase inhibitors: a mechanistic study.

BACKGROUND: We have demonstrated that postshock administration of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, can significantly improve early survival in a highly lethal model of hemorrhagic shock. As the primary insult in hemorrhagic shock is cellular hypoxia, and transcription factor hypoxia-inducible factor-1α (HIF-1α) controls proinflammatory gene expression in macrophages, we hypothesized that SAHA would attenuate the HIF-1α associated proinflammatory pathway in a hypoxic macrophage model. METHODS: Mouse macrophages were exposed to hypoxic conditions (0.5% O2, 10% CO2, and 89.5% N2) at 37°C in the presence or absence of SAHA (10 µmol/L). The cells and culture medium were harvested at 1 hour, 4 hours, and 8 hours. Sham (no hypoxia, no SAHA) served as a control. Western blots were performed to assess protein levels of prolyl hydroxylase 2 (PHD2), HIF-1α, and inducible nitric oxide synthase (iNOS) in the cells. Colorimetric biochemical assay and enzyme-linked immunosorbent assay were used to analyze the release of nitric oxide (NO) and secretion of tumor necrosis factor α (TNF-α), respectively, in the cell culture medium. RESULTS: Hypoxia significantly increased cellular level of HIF-1α (1 hour and 4 hours), gene transcription of iNOS (4 hours and 8 hours), iNOS protein (8 hours), NO production (8 hours), and TNF-α secretion (4 hours and 8 hours). SAHA treatment attenuated all of the above hypoxia-induced alterations in the macrophages. In addition, SAHA treatment significantly increased cellular level of PHD2, one of the upstream negative regulators of HIF-1α, at 1 hour. CONCLUSIONS: Treatment with SAHA attenuates hypoxia-HIF-1α-inflammatory pathway in macrophages and suppresses hypoxia-induced release of proinflammatory NO and TNF-α. SAHA also causes an early increase in cellular PHD2, which provides, at least in part, a new explanation for the decrease in the HIF-1α protein levels.

Apoptosis-linked gene-2 connects the Raf-1 and ASK1 signalings.

Raf-1 plays important roles in cell proliferation, differentiation, and survival. However, the unique and essential function of Raf-1 is anti-apoptotic. The molecules that mediate Raf-1's anti-apoptotic function are not known. In the course of identifying new substrates of Raf-1, we found that the Raf-1 kinase domain interacted with apoptosis-linked gene-2 (ALG-2) in yeast two-hybrid system. Our further studies showed that Raf-1 phosphorylated ALG-2 in an in vitro kinase assay. We also found that apoptosis signal-regulating kinase 1 (ASK1) strongly phosphorylated ALG-2. Importantly, Raf-1 blocks the ASK1-dependent ALG-2 phosphorylation. Since ALG-2 associates with ASK1, and both ASK1 and ALG-2 are involved in apoptosis, our observations indicate that Raf-1 may mediate its anti-apoptotic function by interrupting ASK1-dependent phosphorylation of ALG-2.

A conformationally sensitive GHR [growth hormone (GH) receptor] antibody: impact on GH signaling and GHR proteolysis.

The GH receptor (GHR) mediates metabolic and somatogenic actions of GH. Its extracellular domain (ECD; residues 1-246) has two subdomains, each with seven beta strands organized into two antiparallel beta sheets, connected by a short hinge region. Most of the ECD residues involved in GH binding reside in subdomain 1, whereas subdomain 2 harbors a dimerization interface between GHR dimers that alters conformation in response to GH. A regulated GHR metalloprotease cleavage site is in the membrane-proximal stem region of subdomain 2. We have identified a monoclonal anti-ECD antibody, anti-GHR(ext-mAb), which recognizes the rabbit and human GHRs by immunoprecipitation, but less so after GH treatment. By immunoblotting and immunoprecipitation, anti-GHR(ext-mAb) recognized a glutathione-S-transferase (GST) fusion incorporating subdomain 2, but not one including subdomain 1. In transient transfection experiments, anti-GHR(ext-mAb) failed to recognize by immunoprecipitation a previously characterized dimerization interface mutant GHR that is incompetent for signaling. In signaling experiments, brief pretreatment of GH-responsive human fibrosarcoma cells with anti-GHR(ext-mAb) dramatically inhibited GH-induced Janus kinase 2 and signal transducer and activator of transcription 5 tyrosine phosphorylation and prevented GH-induced GHR disulfide linkage (a reflection of GH-induced conformational changes). In contrast, anti-GHR(ext-mAb) only partially inhibited radiolabeled GH binding, suggesting its effects on signaling were not simply via inhibition of binding. Furthermore, anti-GHR(ext-mAb) prevented phorbol ester-stimulated GHR proteolysis, but GHR cleavage site mutants were normally recognized by the antibody, indicating that the stem region cleavage site is not a direct epitope. A Fab fragment of anti-GHR(ext-mAb) inhibited GH-induced GHR disulfide linkage and signaling, as well as phorbol ester-induced GHR proteolysis, in a fashion similar to the intact antibody. Thus, our findings suggest that anti-GHR(ext-mAb) has promise as a GH antagonist and as a tool in studies of conformational changes required for GHR activation.

Erythropoietin regulation of Raf-1 and MEK: evidence for a Ras-independent mechanism.

Stimulation of the erythropoietin (EPO) receptor triggers a cascade of signaling events. We reported that EPO upregulates c-myc expression through 2 pathways in BaF3-EpoR cells--a phosphatidylinositol 3-kinase (PI3K) pathway operating on transcriptional initiation and a Raf-1-mitogen-activated protein kinase (MAPK) pathway affecting elongation. We now show that EPO induces phosphorylation of Raf-1 at serine 338 and within the carboxy-terminal domain, resulting in an electrophoretic mobility change (hyperphosphorylation). Importantly, MEK 1 inhibitor PD98059 blocked only the hyperphosphorylation of Raf-1 but not the phosphorylation at serine 338. This inhibition of Raf-1 hyperphosphorylation resulted in increased kinase activity of Raf-1 and increased phosphorylation of MEK, suggesting that the hyperphosphorylation of Raf-1 inhibits its MEK kinase activity. Deletion of the first 184 amino acids of Raf-1, which are involved in its interaction with Ras, had no effect on EPO-induced phosphorylation. Introducing the dominant-negative N17Ras or GAP had no effect on EPO-induced kinase activity of Raf-1 and ELK activation. N17Ras failed to inhibit ELK activation in another cell line-Rauscher murine erythroleukemia- which expresses the EPO receptor endogenously and differentiates in response to the hormone. These results indicate the presence of a Ras-independent mechanism for Raf-1 and MEK activation in these cells.

Heat shock factor 1 contains two functional domains that mediate transcriptional repression of the c-fos and c-fms genes.

Heat shock factor 1 (HSF1), in addition to its pivotal role as a regulator of the heat shock response, functions as a versatile gene repressor. We have investigated the structural domains involved in gene repression using mutational analysis of the hsf1 gene. Our studies indicate that HSF1 contains two adjacent sequences located within the N-terminal half of the protein that mediate the repression of c-fos and c-fms. One region (NF) appears to be involved in quenching transcriptional activation factors on target promoters and binds to the basic zipper transcription factor NF-IL6 required for activation of c-fms and IL-1beta. The NF domain encompasses the leucine zipper 1 and 2 sequences as well as the linker domain between the DNA binding and leucine zipper regions. The function of this domain in gene repression is highly specific for HSF1, and the homologous region from conserved family member HSF2 does not restore repressive function in HSF2/HSF1 chimeras. In addition, HSF2 is not capable of binding to NF-IL6. The NF domain, although necessary for repression, is not sufficient, and a second region (REP) occupying a portion of the regulatory domain is required for repression. Neither domain functions independently, and both are required for repression. Furthermore, we constructed dominant inhibitors of c-fos repression by HSF1, which also blocked the repression of c-fms and IL-1beta, suggesting a shared mechanism for repression of these genes by HSF1. Our studies suggest a complex mechanism for gene repression by HSF1 involving the binding to and quenching of activating factors on target promoters. Mapping the structural domains involved in this process should permit further characterization of molecular mechanisms that mediate repression.

NF-IL6 and HSF1 have mutually antagonistic effects on transcription in monocytic cells.

We have examined the functional antagonism between the regulator of the heat shock response, HSF1, and NF-IL6, which plays a major role in control of the acute phase response (APR). Agents that activate HSF1 such as heat shock and sodium salicylate inhibit NF-IL6 induced transcription while NF-IL6 activators such as lipopolysaccharide (LPS) and interleukin 6 (IL-6) repressed the stress responsive HSP70B promoter. In transfection studies, the inhibitory effects of HSF1 and NF-IL6 on the c-fms promoter were shown to be highly dose-dependent. Furthermore, heat shock is inhibitory to differentiation-linked expression of macrophage colony stimulating factor (M-CSF) receptor, product of the c-fms gene, which is transcriptionally activated by NF-IL6 but repressed by HSF1. Our studies suggest a strong mutual antagonism between the heat shock response and APR, which may influence the sensitivity and duration of inflammatory responses.

Heat shock factor 1 represses transcription of the IL-1beta gene through physical interaction with the nuclear factor of interleukin 6.

Heat shock factor (HSF) 1 is the major heat shock transcription factor that regulates stress-inducible synthesis of heat shock proteins and is also essential in protection against endotoxic shock. Following our previous study, which demonstrated the transcriptional repression of the IL-1beta gene by HSF1 (Cahill, C. M., Waterman, W. R., Xie, Y., Auron, P. E., and Calderwood, S. K. (1996) J. Biol. Chem. 271, 24874-24879), we have examined the mechanisms of transcriptional repression. Our studies show that HSF1 represses the lipopolyliposaccharide-induced transcription of the IL-1beta promoter through direct interaction with the nuclear factor of interleukin 6 (NF-IL6, also known as CCAAT enhancer binding protein (C/EBPbeta), an essential regulator in IL-1beta transcription. We show for the first time that HSF1 binds directly to NF-IL6 in vivo and antagonizes its activity. The HSF1/NF-IL6 interaction involves a sequence of HSF1 containing the trimerization and regulatory domains and the bZip region of NF-IL6. HSF1 has little effect on IL-1beta promoter activity stimulated by the essential monocytic transcription factor Spi.1 but is strongly inhibitory to transcriptional activation by NF-IL6 and to the synergistic activation by NF-IL6 and Spi.1. Because of its ability to bind to specific C/EBP elements in the promoters of multiple genes and its ability to interact with other transcription factors, NF-IL6 is involved in transcriptional regulation of a wide range of genes. Interaction between HSF1 and NF-IL6 could thus be an important mechanism in HSF1 regulation of general gene transcription during endotoxin stress.