Tunable transmission and harmonic generation in nonlinear metamaterials

We study the properties of a tunable nonlinear metamaterial operating at microwave frequencies. We fabricate the nonlinear metamaterial composed of double split-ring resonators and wires where a varactor diode is introduced into each resonator so that the magnetic resonance can be tuned dynamically by varying the input power. We show that at higher powers the transmission of the metamaterial becomes power dependent, and we demonstrate experimentally power-dependent transmission properties and selective generation of higher harmonics.Comment: 3 page

Withdrawing an explicit request for euthanasia or physician-assisted suicide: a retrospective study on the influence of mental health status and other patient characteristics

BACKGROUND: Mental health status may be closely related to an instability of intentions toward a premature death, but little is known about such instability following an explicit request for euthanasia or physician-assisted suicide (EAS) and patient characteristics associated with a change of mind. METHOD: A questionnaire was sent to 6596 general practitioners in The Netherlands (response rate 60%). Of these, 1681 provided descriptions of the most recent explicit request for EAS they had received in the preceding 18 months. RESULTS: Symptoms of depression and anxiety were related to a change of mind, but no relationship was found with the total score of the NOSGER Mood Dimension. Multinomial regression analysis revealed that patients who changed their mind had more mental health problems and less mental clarity than those who died by EAS. They also had fewer general health problems, had less unbearable and pointless suffering (according to the physician), were less concerned about loss of dignity and alternative treatment options were more frequently available. A further analysis revealed that mental health problems were more prevalent among patients whose requests were refused than among those who changed their mind. The physicians' evaluations of the reasons why a patient requested EAS were similar to a more objective measure of the patient characteristics. CONCLUSIONS: These findings suggest that mental health status must be carefully assessed, and possible instability of desire must be taken into account in the course of a request for EAS. These results require replication, and future studies should adopt a prospective metho

Structural model of dodecameric heat-shock protein Hsp21:Flexible N-terminal arms interact with client proteins while C-terminal tails maintain the dodecamer and chaperone activity

Small heat-shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently, there is only one high-resolution structure of a plant sHsp published, that of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminal arms than Hsp16.9, with a functionally important and conserved methionine-rich motif. To provide a framework for investigating structure-function relationships of Hsp21 and understanding these sequence variations, we developed a structural model of Hsp21 based on homology modeling, cryo-EM, cross-linking mass spectrometry, NMR, and small-angle X-ray scattering. Our data suggest a dodecameric arrangement of two trimer-of-dimer discs stabilized by the C-terminal tails, possibly through tail-to-tail interactions between the discs, mediated through extended IXVXI motifs. Our model further suggests that six N-terminal arms are located on the outside of the dodecamer, accessible for interaction with client proteins, and distinct from previous undefined or inwardly facing arms. To test the importance of the IXVXI motif, we created the point mutant V181A, which, as expected, disrupts the Hsp21 dodecamer and decreases chaperone activity. Finally, our data emphasize that sHsp chaperone efficiency depends on oligomerization and that client interactions can occur both with and without oligomer dissociation. These results provide a generalizable workflow to explore sHsps, expand our understanding of sHsp structural motifs, and provide a testable Hsp21 structure model to inform future investigations

Exploring the Role of Relational Practices in Water Governance Using a Game-Based Approach

The growing complexity and interdependence of water management processes requires the involvement of multiple stakeholders in water governance. Multi-party collaboration is increasingly vital at both the strategy development and implementation levels. Multi-party collaboration involves a process of joint decision-making among key stakeholders in a problem domain directed towards the future of that domain. However, the common goal is not present from the beginning; rather, the common goal emerges during the process of collaboration. Unfortunately, when the conflicting interests of different actors are at stake, the large majority of environmental multi-party efforts often do not reliably deliver sustainable improvements to policy and/or practice. One of the reasons for this, which has been long established by many case studies, is that social learning with a focus on relational practices is missing. The purpose of this paper is to present the design and initial results of a pilot study that utilized a game-based approach to explore the effects of relational practices on the effectiveness of water governance. This paper verifies the methods used by addressing the following question: are game mechanisms, protocols for facilitation and observation, the recording of decisions and results, and participant surveys adequate to reliably test hypotheses about behavioral decisions related to water governance? We used the “Lords of the Valley” (LOV) game, which focuses on the local-level management of a hypothetical river valley involving many stakeholders. We used an observation protocol to collect data on the quality of relational practices and compared this data with the quantitative outcomes achieved by participants in the game. In this pilot study, we ran the game three times with different groups of participants, and here we provide the outcomes within the context of verifying and improving the methods

A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila

Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens

Cobalt boride modified with N-doped carbon nanotubes as a high-performance bifunctional oxygen electrocatalyst

The development of reversible oxygen electrodes, able to drive both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), is still a great challenge. We describe a very efficient and stable bifunctional electrocatalytic system for reversible oxygen electrodes obtained by direct CVD growth of nitrogen-doped carbon nanotubes (NCNTs) on the surface of cobalt boride (CoB) nanoparticles. A detailed investigation of the crystalline structure and elemental distribution of CoB before and after NCNT growth reveals that the NCNTs grow on small CoB nanoparticles formed in the CVD process. The resultant CoB/NCNT system exhibited outstanding activity in catalyzing both the OER and the ORR in 0.1 M KOH with an overvoltage difference of only 0.73 V between the ORR at -1 mA cm⁻² and the OER at +10 mA cm⁻². The proposed CoB/NCNT catalyst showed stable performance during 50 h of OER stability assessment in 0.1 M KOH. Moreover, CoB/NCNT spray-coated on a gas diffusion layer as an air-breathing electrode proved its high durability during 170 galvanostatic charge-discharge (OER/ORR) test cycles (around 30 h) at ±10 mA cm⁻² in 6 M KOH, making it an excellent bifunctional catalyst for potential Zn-air battery application

S-100B as an extra selection tool for FDG PET/CT scanning in follow-up of AJCC stage III melanoma patients

Background and Objectives This current study assessed the value of S-100B measurement to guide fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scanning for detecting recurrent disease in stage III melanoma patients. Methods This study included 100 stage III melanoma patients in follow-up after curative lymph node dissection. Follow-up visits included physical examination and S-100B monitoring. FDG PET/CT scanning was indicated by clinical symptoms and/or elevated S-100B. Results Of 100 patients, 13 (13%) had elevated S-100B without clinical symptoms, of whom 7 (54%) showed disease evidence upon FDG PET/CT scanning. Twenty-six patients (26%) had clinical symptoms with normal S-100B and FDG PET/CT revealed metastasis in 20 (77%). Three patients had clinical symptoms and elevated S-100B, and FDG PET/CT revealed metastasis in all three (100%). Overall, FDG PET/CT scanning revealed metastasis in 30 of the 42 patients (71.4%). For seven recurrences, elevated S-100B prompted early detection of asymptomatic disease; 10% of all asymptomatic patients in follow-up, 23% of all patients with recurrent disease. Conclusion S-100B cannot exclude recurrent disease during follow-up of stage III melanoma. However, adding S-100B measurement to standard clinical assessment can guide FDG PET/CT scanning for detecting recurrent melanoma

Aerodynamic Shape Optimization of a Blended-Wing-Body Aircraft

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106465/1/AIAA2013-283.pd