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This paper presents a new technique for the detection of islanding conditions in electrical power systems. This problem is especially prevalent in systems with significant penetrations of distributed renewable generation. The proposed technique is based on the application of principal component analysis (PCA) to data sets of wide-area frequency measurements, recorded by phasor measurement units. The PCA approach was able to detect islanding accurately and quickly when compared with conventional RoCoF techniques, as well as with the frequency difference and change of angle difference methods recently proposed in the literature. The reliability and accuracy of the proposed PCA approach is demonstrated using a number of test cases, which consider both islanding and non-islanding events. The test cases are based on real data, recorded from several phasor measurement units located in the UK power system.

The monitoring of multivariate systems that exhibit non‐Gaussian behavior is addressed. Existing work advocates the use of independent component analysis (ICA) to extract the underlying non‐Gaussian data structure. Since some of the source signals may be Gaussian, the use of principal component analysis (PCA) is proposed to capture the Gaussian and non‐Gaussian source signals. A subsequent application of ICA then allows the extraction of non‐Gaussian components from the retained principal components (PCs). A further contribution is the utilization of a support vector data description to determine a confidence limit for the non‐Gaussian components. Finally, a statistical test is developed for determining how many non‐Gaussian components are encapsulated within the retained PCs, and associated monitoring statistics are defined. The utility of the proposed scheme is demonstrated by a simulation example, and the analysis of recorded data from an industrial melter. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Melanoma differentiation associated gene-7 (Mda-7)/IL-24 was previously cloned into ZD55 (an adenovirus with E1B55 deleted) to form ZD55-IL-24, which had much better antitumor effect than Ad-IL-24. According to its good antitumor properties, ZD55-IL-24 has been used in preclinical studies. But ZD55-IL-24 alone still could not completely eradicate established tumors in all nude mice. It was reported that IL-24 could induce and enhance the activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) (a member of tumor necrosis factor (TNF) superfamily). Accordingly, the combined use of ZD55-IL-24 and ZD55-TRAIL was carried out in this study. Treatment with both ZD55-IL-24 and ZD55-TRAIL could induce more significant apoptosis in cancer cells in vitro compared with ZD55-IL-24 or ZD55-TRAIL alone. The combination of the two replicative adenoviruses had better antitumor activity in vivo than that of single oncolytic adenovirus and led to complete eradication of xenograft tumors in all treated mice. Upregulation of TRAIL was observed in tumor cells infected with ZD55-IL-24 and studies of the apoptotic cascade regulators indicate that ZD55-IL-24 could further enhance the activation of apoptosis through the TNF family of death receptors. We demonstrated for the first time the potential therapeutic effect of combined ZD55-IL-24 with ZD55-TRAIL for the targeted therapy of cancer.

Conditionally replicating adenoviruses (CRAds) represent a promising new platform for anticancer therapy. However, CRAds have been evaluated little in hematopoietic malignancies because of the lack of expression of coxsackie adenovirus receptor (CAR) on their cell surface. In this study, we showed that CAR was expressed on two types of lymphoblastic leukemia cell lines and primary leukemia cells, and that ZD55, a CRAd, exerted a potent antileukemia effect in vitro and in vivo. Furthermore, ZD55 expressing melanoma differentiation-associated gene-7/interleukin-24 (ZD55-IL-24) elicited significant enhanced antileukemia activity comparing with ZD55, concomitant with upregulation of RNA-dependent protein kinase R (PKR), increased phosphorylation of p38 mitogen-activated protein kinase (MAPK), and induction of endoplasmic reticulum (ER) stress. These data for the first time indicate that MDA-7/IL-24 exerts its antitumor effect on leukemia cells via multiple pathways, and suggest that oncolytic adenoviruses, ZD55 and ZD55-IL-24 could potentially be used against CAR-expressing hematological malignancies such as B-lymphoblastic leukemia/ lymphoma and some myeloid leukemia.

Apollon, a membrane-associated inhibitor of apoptosis protein, protects cells against apoptosis and is upregulated in certain tumor cells. In this study, the effects of Apollon protein knockdown by RNA interference on the growth of human HeLa, HT-1080 and MCF-7 cells in vitro and in vivo were investigated. An oncolytic adenovirus (ZD55) containing the RNA polymerase III-dependent U6 promoter to express short hairpin RNA (shRNA) directed against Apollon (ZD55-siApollon) was constructed. Our data show that ZD55-siApollon successfully exerts a gene knockdown effect and causes the inhibition of tumor cell growth both in culture and in athymic mice in vivo. Cell cycle analysis, 4 0 ,6-diamidino-2-phenylindole staining and western blot analysis reveal that ZD55-siApollon-mediated suppression of Apollon induces apoptosis. Intratumoral injection of ZD55-siApollon significantly inhibits tumor growth in HT-1080 xenograft mice. Furthermore, ZD55-siApollon enhances the antitumor effect of 5-fluorouracil, a chemotherapeutic agent. In conclusion, these results suggest that the depletion of Apollon by oncolytic adenovirus-shRNA delivery system provides a promising method for cancer therapy.

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