Co-inversion of a scattering cavity and its internal sources: uniqueness, decoupling and imaging

This paper concerns the simultaneous reconstruction of a sound-soft cavity and its excitation sources from the total-field data. Using the single-layer potential representations on two measurement curves, this co-inversion problem can be decoupled into two inverse problems: an inverse cavity scattering problem and an inverse source problem. This novel decoupling technique is fast and easy to implement since it is based on a linear system of integral equations. Then the uncoupled subproblems are respectively solved by the modified optimization and sampling method. We also establish the uniqueness of this co-inversion problem and analyze the stability of our method. Several numerical examples are presented to demonstrate the feasibility and effectiveness of the proposed method.Comment: 21 pages, 7 figure

The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins

Tumor necrosis factor α (TNF-α)is a host inflammatory factor. Bacteria increase TNF-α expression in a variety of human diseases including infectious diseases, inflammatory bowel diseases, and cancer. It is unknown, however, how TNF-α directly modulates bacterial protein expression during intestinal infection and chronic inflammation. In the current study, we hypothesize that Salmonella typhimurium senses TNF-α and show that TNF-α treatment modulates Salmonella virulent proteins (called effectors), thus changing the host-bacterial interaction in intestinal epithelial cells. We investigated the expression of 23 Salmonella effectors after TNF-α exposure. We found that TNF-α treatment led to differential effector expression: effector SipA was increased by TNF-α treatment, whereas the expression levels of other effectors, including gogB and spvB, decreased in the presence of TNF-α. We verified the protein expression of Salmonella effectors AvrA and SipA by Western blots. Furthermore, we used intestinal epithelial cells as our experimental model to explore the response of human intestinal cells to TNF-α pretreated Salmonella. More bacterial invasion was found in host cells colonized with Salmonella strains pretreated with TNF-α compared to Salmonella without TNF-α treatment. TNF-α pretreated Salmonella induced higher proinflammatory JNK signalling responses compared to the Salmonella strains without TNF-α exposure. Exposure to TNF-α made Salmonella to induce more inflammatory cytokine IL-8 in intestinal epithelial cells. JNK inhibitor treatment was able to suppress the effects of TNF-pretreated-Salmonella in enhancing expressions of phosphorylated-JNK and c-jun and secretion of IL-8. Overall, our study provides new insights into Salmonella-host interactions in intestinal inflammation

Consistency maintenance for evolving feature models

Software product line (SPL) techniques handle the construction of customized systems. One of the most common representations of the decisions a customer can make in SPLs is feature models (FMs). An FM represents the relationships among common and variable features in an SPL. Features are a representation of the characteristics in a system that are relevant to customers. FMs are subject to change since the set of features and their relationships can change along an SPL lifecycle. Due to this evolution, the consistency of FMs may be compromised. There exist some approaches to detect and explain inconsistencies in FMs, however this process can take a long time for large FMs. In this paper we present a complementary approach to dealing with inconsistencies in FM evolution scenarios that improves the performance for existing approaches reducing the impact of change to the smallest part of an FM that changes. To achieve our goal, we formalize FMs from an ontological perspective and define constraints that must be satisfied in FMs to be consistent. We define a set of primitive operations that modify FMs and which are responsible for the FM evolution, analyzing their impact on the FM consistency. We propose a set of predefined strategies to keep the consistency for error-prone operations. As a proof-of-concept we present the results of our experiments, where we check for the effectiveness and efficiency of our approach in FMs with thousands of features. Although our approach is limited by the kinds of consistency constraints and the primitive operations we define, the experiments present a significant improvement in performance results in those cases where they are applicable.Comisión Interministerial de Ciencia y Tecnología TIN2009-07366Junta de Andalucía TIC-5906Junta de Andalucía P07-TIC-253

Vitamin D receptor protects against dysbiosis and tumorigenesis via the JAK/STAT pathway in intestine

BACKGROUND & AIMS: Vitamin D exerts regulatory roles via vitamin D receptor (VDR) in mucosal immunity, host defense, and inflammation involving host factors and microbiome. Human Vdr gene variation shapes the microbiome and VDR deletion leads to dysbiosis. Low VDR expression and diminished vitamin D/VDR signaling are observed in colon cancer. Nevertheless, how intestinal epithelial VDR is involved in tumorigenesis through gut microbiota remains unknown. We hypothesized that intestinal VDR protects mice against dysbiosis via modulating the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway in tumorigenesis. METHODS: To test our hypothesis, we used an azoxymethane/dextran sulfate sodium-induced cancer model in intestinal VDR conditional knockout (VDR RESULTS: VDR CONCLUSIONS: We provide insights into the mechanism of VDR dysfunction leading to dysbiosis and tumorigenesis. It indicates a new target: microbiome and VDR for the prevention of cancer

Chronic Effects of a Salmonella Type III Secretion Effector Protein AvrA In Vivo

Salmonella infection is a common public health problem that can become chronic and increase the risk of inflammatory bowel diseases and cancer. AvrA is a Salmonella bacterial type III secretion effector protein. Increasing evidence demonstrates that AvrA is a multi-functional enzyme with critical roles in inhibiting inflammation, regulating apoptosis, and enhancing proliferation. However, the chronic effects of Salmonella and effector AvrA in vivo are still unknown. Moreover, alive, mutated, non-invasive Salmonella is used as a vector to specifically target cancer cells. However, studies are lacking on chronic infection with non-pathogenic or mutated Salmonella in the host.We infected mice with Salmonella Typhimurium for 27 weeks and investigated the physiological effects as well as the role of AvrA in intestinal inflammation. We found altered body weight, intestinal pathology, and bacterial translocation in spleen, liver, and gallbladder in chronically Salmonella-infected mice. Moreover, AvrA suppressed intestinal inflammation and inhibited the secretion of cytokines IL-12, IFN-gamma, and TNF-alpha. AvrA expression in Salmonella enhanced its invasion ability. Liver abscess and Salmonella translocation in the gallbladder were observed and may be associated with AvrA expression in Salmonella.We created a mouse model with persistent Salmonella infection in vivo. Our study further emphasizes the importance of the Salmonella effector protein AvrA in intestinal inflammation, bacterial translocation, and chronic infection in vivo

Wnt2 inhibits enteric bacterial-induced inflammation in intestinal epithelial cells:

Wnt signaling plays an essential role in gastrointestinal epithelial proliferation. Most investigations have focused on developmental and immune responses. Bacterial infection can be chronic and increases the risk of inflammatory bowel disease and colitis-associated cancer. However, we lack studies on how bacteria regulate Wnt proteins and how Wnts modulate the host responses to enteric bacteria. This study investigated the effects of Salmonella and E. coli on Wnt2, one of the Wnt family members, in intestinal epithelia cells

Field Emission Properties and Fabrication of CdS Nanotube Arrays

A large area arrays (ca. 40 cm2) of CdS nanotube on silicon wafer are successfully fabricated by the method of layer-by-layer deposition cycle. The wall thicknesses of CdS nanotubes are tuned by controlling the times of layer-by-layer deposition cycle. The field emission (FE) properties of CdS nanotube arrays are investigated for the first time. The arrays of CdS nanotube with thin wall exhibit better FE properties, a lower turn-on field, and a higher field enhancement factor than that of the arrays of CdS nanotube with thick wall, for which the ratio of length to the wall thickness of the CdS nanotubes have played an important role. With increasing the wall thickness of CdS nanotube, the enhancement factorβdecreases and the values of turn-on field and threshold field increase

Effect of Aspect Ratio on Field Emission Properties of ZnO Nanorod Arrays

ZnO nanorod arrays are prepared on a silicon wafer through a multi-step hydrothermal process. The aspect ratios and densities of the ZnO nanorod arrays are controlled by adjusting the reaction times and concentrations of solution. The investigation of field emission properties of ZnO nanorod arrays revealed a strong dependency on the aspect ratio and their density. The aspect ratio and spacing of ZnO nanorod arrays are 39 and 167 nm (sample C), respectively, to exhibit the best field emission properties. The turn-on field and threshold field of the nanorod arrays are 3.83 V/μm and 5.65 V/μm, respectively. Importantly, the sample C shows a highest enhancement of factorβ, which is 2612. The result shows that an optimum density and aspect ratio of ZnO nanorod arrays have high efficiency of field emission

Axin1 Prevents Salmonella Invasiveness and Inflammatory Response in Intestinal Epithelial Cells

Axin1 and its homolog Axin2 are scaffold proteins essential for regulating Wnt signaling. Axin-dependent regulation of Wnt is important for various developmental processes and human diseases. However, the involvement of Axin1 and Axin2 in host defense and inflammation remains to be determined.Here, we report that Axin1, but not Axin2, plays an essential role in host-pathogen interaction mediated by the Wnt pathway. Pathogenic Salmonella colonization greatly reduces the level of Axin1 in intestinal epithelial cells. This reduction is regulated at the posttranslational level in early onset of the bacterial infection. Further analysis reveals that the DIX domain and Ser614 of Axin1 are necessary for the Salmonella-mediated modulation through ubiquitination and SUMOylation.Axin1 apparently has a preventive effect on bacterial invasiveness and inflammatory response during the early stages of infection. The results suggest a distinct biological function of Axin1 and Axin2 in infectious disease and intestinal inflammation while they are functionally equivalent in developmental settings