Domain wall switching: optimizing the energy landscape

It has recently been suggested that exchange spring media offer a way to increase media density without causing thermal instability (superparamagnetism), by using a hard and a soft layer coupled by exchange. Victora has suggested a figure of merit xi = 2 E_b/mu_0 m_s H_sw, the ratio of the energy barrier to that of a Stoner-Wohlfarth system with the same switching field, which is 1 for a Stoner-Wohlfarth (coherently switching) particle and 2 for an optimal two-layer composite medium. A number of theoretical approaches have been used for this problem (e.g., various numbers of coupled Stoner-Wohlfarth layers and continuum micromagnetics). In this paper we show that many of these approaches can be regarded as special cases or approximations to a variational formulation of the problem, in which the energy is minimized for fixed magnetization. The results can be easily visualized in terms of a plot of the energy as a function of magnetic moment m_z, in which both the switching field [the maximum slope of E(m_z)] and the stability (determined by the energy barrier E_b) are geometrically visible. In this formulation we can prove a rigorous limit on the figure of merit xi, which can be no higher than 4. We also show that a quadratic anistropy suggested by Suess et al comes very close to this limit.Comment: Acccepted for proceedings of Jan. 2007 MMM Meeting, paper BE-0

Monocyte depletion enhances neutrophil influx and proneural to mesenchymal transition in glioblastoma

Myeloid cells comprise the majority of immune cells in tumors, contributing to tumor growth and therapeutic resistance. Incomplete understanding of myeloid cells response to tumor driver mutation and therapeutic intervention impedes effective therapeutic design. Here, by leveraging CRISPR/Cas9-based genome editing, we generate a mouse model that is deficient of all monocyte chemoattractant proteins. Using this strain, we effectively abolish monocyte infiltration in genetically engineered murine models of de novo glioblastoma (GBM) and hepatocellular carcinoma (HCC), which show differential enrichment patterns for monocytes and neutrophils. Eliminating monocyte chemoattraction in monocyte enriched PDGFB-driven GBM invokes a compensatory neutrophil influx, while having no effect on Nf1-silenced GBM model. Single-cell RNA sequencing reveals that intratumoral neutrophils promote proneural-to-mesenchymal transition and increase hypoxia in PDGFB-driven GBM. We further demonstrate neutrophil-derived TNF-a directly drives mesenchymal transition in PDGFB-driven primary GBM cells. Genetic or pharmacological inhibiting neutrophils in HCC or monocyte-deficient PDGFB-driven and Nf1-silenced GBM models extend the survival of tumor-bearing mice. Our findings demonstrate tumor-type and genotype dependent infiltration and function of monocytes and neutrophils and highlight the importance of targeting them simultaneously for cancer treatments

A paracrine circuit of IL-1β/IL-1R1 between myeloid and tumor cells drives genotype-dependent glioblastoma progression

Monocytes and monocyte-derived macrophages (MDMs) from blood circulation infiltrate glioblastoma (GBM) and promote growth. Here, we show that PDGFB-driven GBM cells induce the expression of the potent proinflammatory cytokine IL-1β in MDM, which engages IL-1R1 in tumor cells, activates the NF-κB pathway, and subsequently leads to induction of monocyte chemoattractant proteins (MCPs). Thus, a feedforward paracrine circuit of IL-1β/IL-1R1 between tumors and MDM creates an interdependence driving PDGFB-driven GBM progression. Genetic loss or locally antagonizing IL-1β/IL-1R1 leads to reduced MDM infiltration, diminished tumor growth, and reduced exhausted CD8+ T cells and thereby extends the survival of tumor-bearing mice. In contrast to IL-1β, IL-1α exhibits antitumor effects. Genetic deletion of Il1a/b is associated with decreased recruitment of lymphoid cells and loss-of-interferon signaling in various immune populations and subsets of malignant cells and is associated with decreased survival time of PDGFB-driven tumor-bearing mice. In contrast to PDGFB-driven GBM, Nf1-silenced tumors have a constitutively active NF-κB pathway, which drives the expression of MCPs to recruit monocytes into tumors. These results indicate local antagonism of IL-1β could be considered as an effective therapy specifically for proneural GBM

Conductance Quantization in Graphene Nanoribbons

We report the experimental observation of conductance quantization in graphene nanoribbons, where 1D transport subbands are formed due to the lateral quantum confinement. We show that this quantization in graphene nanoribbons can be observed at temperatures as high as 80 K and channel lengths as long as 1.7 $\mu$m. The observed quantization is in agreement with that predicted by theoretical calculations

Visualization Measurement of the Flame Temperature in a Power Station Using the Colorimetric Method

AbstractThis paper presents a study on the measurement of the temperature distribution in a power station based on an optical flame/temperature visualization system. This system operates upon the colorimetric principle combining advanced optical sensing and digital image processing techniques. The system was calibrated using a blackbody furnace as standard temperature source. Experimental results are obtained from a 300MW power station boiler. As the measurement height changed, the temperature captured by the system also changed. The maximum temperature occurs on the upper level of the burners. The temperature decreased when the load went down and tended to be stable when the load remained steady. Experimental results also reveal that this system is capable of online measurements of the temperature distribution in a combustion zone. This system can potentially be applied to many areas such as power generation, metallurgy or chemical engineering

Attorney on trial: When lawyers met phony lawyers in republican Beijing

China underwent tremendous changes in social systems during the Republican period. Among these changes was the government’s introduction into Chinese society of a new legal profession based on Western ideology. Relying mainly on Shanghai archival records, previous scholarship has suggested that, unlike the traditional litigation masters who had always been despised by the authorities, the new Chinese lawyers quickly rose to respectable social and economic status. However, the historical findings presented in the current article challenge this perception by showing that in a city with a more deeply rooted indigenous legal tradition and less influence from Western lawyers, as in Beijing, the new Chinese lawyers faced resistance from the legacy of the old legal culture that permeated the new system. For a considerable period of time after the establishment of the Republic, the people of Beijing still continued to hire unqualified, “phony” lawyers in lawsuits, and some of these phony lawyers had previously been litigation masters under the Qing dynasty. Although legal reform was instigated by the central government as a unified policy, its implementation was bound to vary in different regions according to the influence of the traditional legal culture. It is clear that the situation in Shanghai and other treaty ports does not represent the situation throughout the entire country, nor even in other coastal regions. Therefore, to make more sense of legal reform in China, one should evaluate the development of legal reform in a particular city or region against its social and ideological backdrop. This approach may provide insights not only into the legal reform of the Republican period, but also into the post-Mao era when once again a modern legal system based on the Western model has been introduced, this time within a socialist system.published_or_final_versio

Characterization of a p75NTR Apoptotic Signaling Pathway Using a Novel Cellular Model

The p75 neurotrophin receptor (p75(NTR)) belongs to the tumor necrosis factor receptor/nerve growth factor receptor superfamily. In some cells derived from neuronal tissues it causes cell death through a poorly characterized pathway. We developed a neuronal system using conditionally immortalized striatal neurons, in which the expression of p75(NTR) is inducibly controlled by the ecdysone receptor. In these cells p75(NTR) induces apoptosis through its death domain in a nerve growth factor-independent manner. Caspases 9, 6, and 3 are activated by receptor expression indicating the activation of the common effector pathway of apoptosis. Cell death is blocked by a dominant negative form of caspase 9 and Bcl-X(L) consistent with a pathway that involves mitochondria. Significantly, the viral flice inhibitory protein E8 protects from p75(NTR)-induced cell death indicating that death effector domains are involved. A p75(NTR) construct with a deleted death domain dominantly interferes with p75(NTR) signaling, implying that receptor multimerization is required. However, in contrast to the other receptors of the family, p75(NTR)-mediated apoptosis does not involve the adaptor proteins Fas-associated death domain protein or tumor necrosis factor-associated death domain protein, and the apical caspase 8 is not activated. We conclude that p75(NTR) signals apoptosis by similar mechanisms as other death receptors but uses different adaptors and apical caspases

Heterogeneous Multi-wavelength Optical Injection Locked System-on-chip: a Proposal & Proof-of-concept Experiment

We present proof-of-concept work towards an integrated multi-λ optical injection locked system-on-chip using just one master laser. Tremendous improvement of direct modulation (4→20 Gb/s) and single-mode operation on slave microring laser was achieved

Formal planning and the reshaping of public sector professional work

This paper deals with the ‘managerialization’ of public sector professional work. Specifically, it will focus on the role of formal planning practices (as expressed in strategic planning, project management and budgeting practices) in changing public sector professional work. Planning and accounting are at the heart of public sector reforms, responding to a logic of having public service professionals transparent on what they do, on how they pursue their goals, and accountable on the use of resources and on results. Thus planning and accounting practices have been transferred from private sector management models to public, professional organizations. Yet public sector professional organizations can be conceived as a pluralistic setting characterized by diffuse power, fragmented objectives and knowledgebased and are deeply embedded in public administration regulatory logics: how can management models deriving from private, hierarchical firms be applied to the specificities and complexities of public, pluralistic settings? What is the specific meaning of formal planning practices in such complex contexts? Based on a qualitative, single case study design, this paper will show how the planning system (in its manifestation of strategic planning, project management and budgeting) applied in a public hospital apparently ‘fails’ when its deliberate role of serving as a tool for decisions is considered. Yet it is widely in use and widely accepted by professionals as well. Conclusions on the value of formal planning when other emergent roles are taken into account will be discussed