30 research outputs found
ON THE HARDY-CARLEMAN INEQUALITY FOR A NEGATIVE EXPONENT
In this paper we settle an open problem raised by B. Yang (2005, Taiwanese Journal of Mathematics 9, 469-475), by using Holder's and Bernoulli's inequalities. We give a strengthened Hardy-Carleman inequality for a negative exponent.Peer reviewe
On the Uniqueness of Limit Cycles in a Generalized Lienard System
Kooij and Sun (J Math Anal Appl 208:260-276, 1997) proposed a theorem to guarantee the uniqueness of limit cycles for the generalized Lienard system dx/dt=h(y)-F(x),mml:mspace width="4pt"mml:mspacedy/dt=-g(x). We will give a counterexample to their theorem. Moreover, we shall give some sufficient conditions for the existence, uniqueness and hyperbolicity of limit cycles.Peer reviewe
The molecular characterization of a cyclophilin A from Chinese mitten crab Eriocheir sinensis and the antifungal activity of its recombinant protein
Background: Cyclophilin A (CypA), a receptor for the immunosuppressive
agent cyclosporin A (CsA), is a cis-trans peptidyl-prolyl isomerase
(PPIase) which accelerates the cis-trans isomerization of
prolyl-peptide bonds and interacts with a variety of proteins to
regulate their activities. Results: The full-length cDNA of crab
Eriocheir sinensis CypA (EsCypA) was cloned by EST and RACE
technique. The complete sequence of EsCypA cDNA contained a 5\u2019
untranslated region (UTR) of 50 bp, a 3\u2019 UTR of 233 bp with a
polyA tail, and an open reading frame (ORF) of 495 bp encoding a
polypeptide of 164 amino acids with the predicted molecular weight of
17.36 kDa. The deduced amino acid sequence of EsCypA contained two
highly conserved signature sequences of peptidyl-prolyl cis-trans
isomerase and a pro-isomerase domain. The mRNA transcripts of EsCypA
were detectable in all the examined tissues, including haemocytes,
gill, hepatopancreas, gonad, muscle and heart, with higher expression
level in hepatopancreas and gonad. No significant difference in the
relative mRNA expression level of EsCypA was observed during the whole
course of bacteria challenge, whereas it was up-regulated during fungi
challenge. The purified recombinant protein rEsCypA exhibited a
significant PPIase activity and an antifungal activity. Conclusions:
All these results indicated that it was a typical CypA member and
potentially involved in the innate immune responses of crab
IRAK4 mediates colitis-induced tumorigenesis and chemoresistance in colorectal cancer
Aberrant activation of the NF-κB transcription factors underlies chemoresistance in various cancer types, including colorectal cancer (CRC). Targeting the activating mechanisms, particularly with inhibitors to the upstream IκB kinase (IKK) complex, is a promising strategy to augment the effect of chemotherapy. However, clinical success has been limited, largely because of low specificity and toxicities of tested compounds. In solid cancers, the IKKs are driven predominantly by the Toll-like receptor (TLR)/IL-1 receptor family members, which signal through the IL-1 receptor-associated kinases (IRAKs), with isoform 4 (IRAK4) being the most critical. The pathogenic role and therapeutic value of IRAK4 in CRC have not been investigated. We found that IRAK4 inhibition significantly abrogates colitis-induced neoplasm in APCMin/+ mice, and bone marrow transplant experiments showed an essential role of IRAK4 in immune cells during neoplastic progression. Chemotherapy significantly enhances IRAK4 and NF-κB activity in CRC cells through upregulating TLR9 expression, which can in turn be suppressed by IRAK4 and IKK inhibitors, suggesting a feed-forward pathway that protects CRC cells from chemotherapy. Lastly, increased tumor phospho-IRAK4 staining or IRAK4 mRNA expression is associated with significantly worse survival in CRC patients. Our results support targeting IRAK4 to improve the effects of chemotherapy and outcomes in CRC
Induction of cancer neoantigens facilitates development of clinically relevant models for the study of pancreatic cancer immunobiology
Neoantigen burden and CD8 T cell infiltrate are associated with clinical outcome in pancreatic ductal adenocarcinoma (PDAC). A shortcoming of many genetic models of PDAC is the lack of neoantigen burden and limited T cell infiltrate. The goal of the present study was to develop clinically relevant models of PDAC by inducing cancer neoantigens in KP2, a cell line derived from the KPC model of PDAC. KP2 was treated with oxaliplatin and olaparib (OXPARPi), and a resistant cell line was subsequently cloned to generate multiple genetically distinct cell lines (KP2-OXPARPi clones). Clones A and E are sensitive to immune checkpoint inhibition (ICI), exhibit relatively high T cell infiltration, and have significant upregulation of genes involved in antigen presentation, T cell differentiation, and chemokine signaling pathways. Clone B is resistant to ICI and is similar to the parental KP2 cell line in terms of relatively low T cell infiltration and no upregulation of genes involved in the pathways noted above. Tumor/normal exome sequencing and in silico neoantigen prediction confirms successful generation of cancer neoantigens in the KP2-OXPARPi clones and the relative lack of cancer neoantigens in the parental KP2 cell line. Neoantigen vaccine experiments demonstrate that a subset of candidate neoantigens are immunogenic and neoantigen synthetic long peptide vaccines can restrain Clone E tumor growth. Compared to existing models, the KP2-OXPARPi clones better capture the diverse immunobiology of human PDAC and may serve as models for future investigations in cancer immunotherapies and strategies targeting cancer neoantigens in PDAC
TPL2 enforces RAS-induced inflammatory signaling and is activated by point mutations
NF-κB transcription factors, driven by the IRAK/IKK cascade, confer treatment resistance in pancreatic ductal adenocarcinoma (PDAC), a cancer characterized by near-universal KRAS mutation. Through reverse-phase protein array and RNA sequencing we discovered that IRAK4 also contributes substantially to MAPK activation in KRAS-mutant PDAC. IRAK4 ablation completely blocked RAS-induced transformation of human and murine cells. Mechanistically, expression of mutant KRAS stimulated an inflammatory, autocrine IL-1β signaling loop that activated IRAK4 and the MAPK pathway. Downstream of IRAK4, we uncovered TPL2 (also known as MAP3K8 or COT) as the essential kinase that propels both MAPK and NF-κB cascades. Inhibition of TPL2 blocked both MAPK and NF-κB signaling, and suppressed KRAS-mutant cell growth. To counter chemotherapy-induced genotoxic stress, PDAC cells upregulated TLR9, which activated prosurvival IRAK4/TPL2 signaling. Accordingly, a TPL2 inhibitor synergized with chemotherapy to curb PDAC growth in vivo. Finally, from TCGA we characterized 2 MAP3K8 point mutations that hyperactivate MAPK and NF-κB cascades by impeding TPL2 protein degradation. Cancer cell lines naturally harboring these MAP3K8 mutations are strikingly sensitive to TPL2 inhibition, underscoring the need to identify these potentially targetable mutations in patients. Overall, our study establishes TPL2 as a promising therapeutic target in RAS- and MAP3K8-mutant cancers and strongly prompts development of TPL2 inhibitors for preclinical and clinical studies
Transgenic plants of Petunia hybrida harboring the CYP2E1 gene efficiently remove benzene and toluene pollutants and improve resistance to formaldehyde
The CYP2E1 protein belongs to the P450 enzymes family and plays an important role in the metabolism of small molecular and organic pollutants. In this study we generated CYP2E1 transgenic plants of Petunia using Agrobacterium rhizogenes K599. PCR analysis confirmed that the regenerated plants contained the CYP2E1 transgene and the rolB gene of the Ri plasmid. Southern blotting revealed the presence of multiple copies of CYP2E1 in the genome of transgenic plants. Fluorescent quantitative PCR revealed exogenous CYP2E1 gene expression in CYP2E1 transgenic plants at various levels, whereas no like expression was detected in either GUS transgenic plants or wild-types. The absorption of benzene and toluene by transgenic plants was analyzed through quantitative gas chromatography. Transgenic plants with high CYP2E1 expression showed a significant increase in absorption capacity of environmental benzene and toluene, compared to control GUS transgenic and wild type plants. Furthermore, these plants also presented obvious improved resistance to formaldehyde. This study, besides being the first to reveal that the CYP2E1 gene enhances plant resistance to formaldehyde, also furnishes a new method for reducing pollutants, such as benzene, toluene and formaldehyde, by using transgenic flowering horticultural plants
Waving User Experience - a case study of designing bridge experiences on future ships
This thesis aims to study the experiences that a captain would prefer in future ship operations on a tugboat bridge. The case study is based on “operations on future ships”, a case collaborating with Rolls-Royce Marine and other research companies.
In this case study, the subjects covered captains and seafarers who work or used to work on tugboats, cargo ships or supply vessels. Researchers carried out user studies by using methods including field studies and in-depth interviews, which identified several experiences that seafarers may appreciate.
The author concentrates on the tugboat bridge. He set User Experience Targets “sense of control” and “feeling of comfortable in using technology” based on the study findings and developed one tugboat bridge concept. Experts and a top user evaluated this concept.
The results of this study indicate that a sense of control is the experience that captains may expect and enjoy and that a feeling of comfort is still not accepted, though the studies discovered few situations, which seafarers are still suffering uncomfortably
Transgenic plants of Petunia hybrida harboring the CYP2E1 gene efficiently remove benzene and toluene pollutants and improve resistance to formaldehyde
The CYP2E1 protein belongs to the P450 enzymes family and plays an important role in the metabolism of small molecular and organic pollutants. In this study we generated CYP2E1 transgenic plants of Petunia using Agrobacterium rhizogenes K599. PCR analysis confirmed that the regenerated plants contained the CYP2E1 transgene and the rolB gene of the Ri plasmid. Southern blotting revealed the presence of multiple copies of CYP2E1 in the genome of transgenic plants. Fluorescent quantitative PCR revealed exogenous CYP2E1 gene expression in CYP2E1 transgenic plants at various levels, whereas no like expression was detected in either GUS transgenic plants or wild-types. The absorption of benzene and toluene by transgenic plants was analyzed through quantitative gas chromatography. Transgenic plants with high CYP2E1 expression showed a significant increase in absorption capacity of environmental benzene and toluene, compared to control GUS transgenic and wild type plants. Furthermore, these plants also presented obvious improved resistance to formaldehyde. This study, besides being the first to reveal that the CYP2E1 gene enhances plant resistance to formaldehyde, also furnishes a new method for reducing pollutants, such as benzene, toluene and formaldehyde, by using transgenic flowering horticultural plants