Macroporous silicon membranes as electron and x-ray transmissive windows

Macroporous silicon membranes are fabricated whose pores are terminated with 60 nm thin silicon dioxide shells. The transmission of electrons with energies of 5 kV-25 kV through these membranes was investigated reaching a maximum of 22% for 25 kV. Furthermore, the transmission of electromagnetic radiation ranging from the far-infrared to the x-ray region was determined. The results suggest the application of the membrane as window material for electron optics and energy dispersive x-ray detectors

Healer, Witness, or Double Agent? Reexamining the Ethics of Forensic Psychiatry

In recent years, psychiatrists have become ever more prevalent in American courtrooms. Consequently, the issue of when the usual rules of medical ethics should apply to forensic psychiatric encounters has taken on increased importance and is a continuing topic of discussion among both legal and medical scholars. A number of approaches to the problem of forensic psychiatric ethics have been proposed, but none adequately addresses the issues that arise when a forensic encounter develops therapeutic characteristics. This article looks to the rules governing the lawyer-client relationship as a model for a new approach to forensic psychiatric ethics. This new model focuses on the expectations of the evaluee and the ways in which the evaluating psychiatrist shapes those expectations to determine how and when the rules of medical ethics should apply to forensic psychiatric encounters. This article describes and analyzes three previously proposed approaches to that question and the closely related question of when and how a doctor-patient relationship can form in the context of a forensic psychiatric evaluation. It also explains why each of these prior approaches does not sufficiently address the issues that arise when a forensic encounter takes on therapeutic characteristics. Finally, it proposes a new approach that draws inspiration from the rules governing the lawyer-client relationship

Healer, Witness, or Double Agent? Reexamining the Ethics of Forensic Psychiatry

In recent years, psychiatrists have become ever more prevalent in American courtrooms. Consequently, the issue of when the usual rules of medical ethics should apply to forensic psychiatric encounters has taken on increased importance and is a continuing topic of discussion among both legal and medical scholars. A number of approaches to the problem of forensic psychiatric ethics have been proposed, but none adequately addresses the issues that arise when a forensic encounter develops therapeutic characteristics. This article looks to the rules governing the lawyer-client relationship as a model for a new approach to forensic psychiatric ethics. This new model focuses on the expectations of the evaluee and the ways in which the evaluating psychiatrist shapes those expectations to determine how and when the rules of medical ethics should apply to forensic psychiatric encounters. This article describes and analyzes three previously proposed approaches to that question and the closely related question of when and how a doctor-patient relationship can form in the context of a forensic psychiatric evaluation. It also explains why each of these prior approaches does not sufficiently address the issues that arise when a forensic encounter takes on therapeutic characteristics. Finally, it proposes a new approach that draws inspiration from the rules governing the lawyer-client relationship

Predicting land use and soil controls on erosion and sediment redistribution in agricultural loess areas: model development and cross scale verification

This study quantifies soil and land use controls on sediment mobilisation and redistribution in cultivated loess soil landscapes, as these landscapes are frequently used for intensive cultivation and are highly susceptible to erosion. To this end we developed and verified a process based model named CATFLOW-SED at the plot, hillslope and catchment scales. The model relies on an explicit representation of hillslopes and their dominant physiographical characteristics which control overland flow formation, particle detachment and sediment redistribution (transport and sedimentation). Erosion processes are represented by means of the steady state approximation of the sediment continuity equation, their interaction is conceptualized based on the sediment transport capacity of overland flow. Particle detachment is represented by means of a threshold approach accounting for the attacking forces of rainfall and overland flow which need to exceed a threshold in soil erosion resistance to mobilize soil particles (Scherer et al., 2012). Transport capacity of overland flow is represented as proposed by Engelund and Hansen (1967). Top soil particles and aggregates are detached and transported according to their share in the particle size distribution. Size selective deposition of soil particles is determined based on the sink velocity of the various particle size classes. CATFLOW-SED was verified on the plot, hillslope and catchment scale, where either particle detachment or lateral redistribution or sedimentation is the limiting factor, to check whether the respective parameterizations are transferable for simulations at the next higher scale. For verification we used the Weiherbach data set providing plot scale rainfall simulation experiments, long term monitoring of sediment yields on a selected hillslope as well as observed sediment fluxes at the catchment outlet. Our findings corroborate that CATFLOW-SED predicted the sediment loads at all scales within the error margin of the measurements. An accurate prediction of overland flow turned out as being necessary and sufficient to guarantee spatial transferability of erosion parameters optimized at smaller scales to the next higher scale without need for further calibration. Based on the verified model setup, we investigate the efficiency of land use management to mitigate measures in erosion scenarios for cultivated loess landscapes

Three-dimensional macroporous silicon photonic crystal with large photonic band gap

Three-dimensional photonic crystals based on macroporous silicon are fabricated by photoelectrochemical etching and subsequent focused-ion-beam drilling. Reflection measurements show a high reflection in the range of the stopgap and indicate the spectral position of the complete photonic band gap. The onset of diffraction which might influence the measurement is discussed

Functional renormalization and mean-field approach to multiband systems with spin-orbit coupling: Application to the Rashba model with attractive interaction

The functional renormalization group (RG) in combination with Fermi surface patching is a well-established method for studying Fermi liquid instabilities of correlated electron systems. In this article, we further develop this method and combine it with mean-field theory to approach multiband systems with spin-orbit coupling, and we apply this to a tight-binding Rashba model with an attractive, local interaction. The spin dependence of the interaction vertex is fully implemented in a RG flow without SU(2) symmetry, and its momentum dependence is approximated in a refined projection scheme. In particular, we discuss the necessity of including in the RG flow contributions from both bands of the model, even if they are not intersected by the Fermi level. As the leading instability of the Rashba model, we find a superconducting phase with a singlet-type interaction between electrons with opposite momenta. While the gap function has a singlet spin structure, the order parameter indicates an unconventional superconducting phase, with the ratio between singlet and triplet amplitudes being plus or minus one on the Fermi lines of the upper or lower band, respectively. We expect our combined functional RG and mean-field approach to be useful for an unbiased theoretical description of the low-temperature properties of spin-based materials.Comment: consistent with published version in Physical Review B (2016

Silicon-on-insulator-based complementary metal oxide semiconductor integrated optoelectronic platform for biomedical applications

Microscale optical devices enabled by wireless power harvesting and telemetry facilitate manipulation and testing of localized biological environments (e.g., neural recording and stimulation, targeted delivery to cancer cells). Design of integrated microsystems utilizing optical power harvesting and telemetry will enable complex in vivo applications like actuating a single nerve, without the difficult requirement of extreme optical focusing or use of nanoparticles. Silicon-on-insulator (SOI)-based platforms provide a very powerful architecture for such miniaturized platforms as these can be used to fabricate both optoelectronic and microelectronic devices on the same substrate. Near-infrared biomedical optics can be effectively utilized for optical power harvesting to generate optimal results compared with other methods (e.g., RF and acoustic) at submillimeter size scales intended for such designs. We present design and integration techniques of optical power harvesting structures with complementary metal oxide semiconductor platforms using SOI technologies along with monolithically integrated electronics. Such platforms can become the basis of optoelectronic biomedical systems including implants and lab-on-chip systems

Optimization Techniques for Miniaturized Integrated Electrochemical Sensors

Electrochemical sensors are integral components of various integrated sensing applications. In this work, we provide details of optimizing electrochemical sensors for CMOS compatible integrated designs at sub-mm size scales. The focus is on optimization of electrode materials and geometry. We provide design details for both working electrode and reference electrode materials for hydrogen peroxide sensing applications which form the basis for many metabolic sensors. We also present results on geometrical variations in designing such sensors and demonstrate that such considerations are very relevant for optimizing the overall sensor performance. We also present results for such optimized sensors on actual CMOS platforms. The methods presented in this work can be adopted for countless applications of electrochemical sensing platforms

Crossover from Single-Ion to Coherent Non-Fermi Liquid Behavior in Ce1−x_{1-x}Lax_xNi9_9Ge4_4

We report specific heat and magneto-resistance studies on the compound Ce${}_{1-x}$La${}_x$Ni${}_9$Ge${}_4$ for various concentrations over the entire stoichiometric range. Our data reveal single-ion scaling with Ce-concentration between $x = 0.1$ and 0.95. Furthermore, CeNi${}_9$Ge${}_4$ turns out to have the largest ever recorded value of the electronic specific heat $\Delta c/T \approx$ 5.5 J $\rm K^{-2}mol^{-1}$ at $T=0.08$ K which was found in Cerium f-electron lattice systems. In the doped samples $\Delta c/T$ increases logarithmically in the temperature range between 3 K and 50 mK typical for non-Fermi liquid (nFl) behavior, while $\rho$ exhibits a Kondo-like minimum around 30 K, followed by a single-ion local nFl behavior. In contrast to this, CeNi${}_9$Ge${}_4$ flattens out in $\Delta c/T$ below 300 mK and displays a pronounced maximum in the resistivity curve at 1.5 K indicating a coherent heavy fermion groundstate. These properties render the compound Ce${}_{1-x}$La${}_x$Ni${}_9$Ge${}_4$ a unique system on the borderline between Fermi liquid and nFl physics.Comment: 2 pages, 3 figures, SCES0