Wide-range resistivity characterization of semiconductors with terahertz time-domain spectroscopy.

Resistivity is one of the most important characteristics in the semiconductor industry. The most common way to measure resistivity is the four-point probe method, which requires physical contact with the material under test. Terahertz time domain spectroscopy, a fast and non-destructive measurement method, is already well established in the characterization of dielectrics.

Comparing the optical properties and thermal stability of green (TbPO), yellow (DyPO), and red (PrPO) emitting single crystal samples.

Blue, green and red-emitting phosphors for near-UV/blue based phosphor blend converted white-light emitting devices have been investigated extensively over the past years. Herein, we present our results on the optical spectroscopy of single crystal samples of TbPO4, DyPO4 and PrPO4 exhibiting prominent emission at green (545 nm), yellow (574 nm) and red (616 nm) region of the electromagnetic spectrum, respectively. We study the temperature dependence of their emission spectra for excitations at 365 and 455 nm, to mimic experimental conditions for phosphor converted light emitting diodes, to show that their thermal quenching temperature is 730 K for TbPO4 (excitation 365 nm), 490 and 520 K for DyPO4 (excitation at 365 and 455 nm), and 540 K for PrPO4 (excitation 455 nm).

Non-quenching photoluminescence emission up to at least 865 K upon near-UV excitation in a single crystal of orange-red emitting SmPO.

The adjustment of photoluminescence emission spectrum and an enhancement in the thermal stability of red/orange-red emitting phosphors is an important issue for the whole lighting industry. Herein, we present our results on the luminescence spectroscopy of a single crystal sample of SmPO4 exhibiting a prominent orange-red emission at 597 nm, along with a charge-transfer absorption (O2- → Sm3+) around 200 nm. We study the temperature dependence of emission spectra in SmPO4 for excitations at 365 and 455 nm, to mimic experimental conditions for phosphor converted light emitting diodes, to show that the sample has a non-quenching photoluminescence emission up to at least 865 K for an excitation at 365 nm, and ∼865 K for an excitation at wavelength, 455 nm.

Extending the temperature sensing range using Eu luminescence up to 865 K in a single crystal of EuPO.

Temperature evaluation through the measurement of emission intensities (the intensity ratio method) requires two distinct bands, one of which is used as a reference, and the emission intensity of the other is monitored as a function of a change in temperature. Herein, we report the influence of the excitation wavelength and a coupling scheme between the lanthanoid and defect emission from the host lattice to extend the temperature sensing range by using a single crystal of europium(iii) phosphate. The temperature dependence of the emission intensity was studied for different excitation wavelengths: 365 (intraconfigurational 4f2 excitation), 338 (defect excitation), and 254 nm (O2- → Eu3+ charge-transfer excitation), in the temperature range 293-865 K.

Fast 2D Laser-Induced Fluorescence Spectroscopy Mapping of Rare Earth Elements in Rock Samples.

Due to the rapidly increasing use of energy-efficient technologies, the need for complex materials containing rare earth elements (REEs) is steadily growing. The high demand for REEs requires the exploration of new mineral deposits of these valuable elements, as recovery by recycling is still very low. Easy-to-deploy sensor technologies featuring high sensitivity to REEs are required to overcome limitations by traditional techniques, such as X-ray fluorescence.

Food web framework for size-structured populations.

We synthesise traditional unstructured food webs, allometric body size scaling, trait-based modelling, and physiologically structured modelling to provide a novel and ecologically relevant tool for size-structured food webs. The framework allows food web models to include ontogenetic growth and life-history omnivory at the individual level by resolving the population structure of each species as a size-spectrum. Each species is characterised by the trait 'size at maturation', and all model parameters are made species independent through scaling with individual body size and size at maturation.

Therapy of isolated calf muscle vein thrombosis: a randomized, controlled study.

Background: Treatment of isolated calf muscle vein thrombosis (ICMVT) is controversial. There are no data from prospective, controlled studies. Objective of this article was to compare the efficacy and safety of a short-term course of anticoagulation with compression therapy alone.

[Anticoagulant therapy in venous thromboembolism].

Venous thromboembolism (VTE) is a common cause of morbidity and mortality with an estimated annual incidence of 1 : 1,000. Patients show individual risk profiles with regard to recurrent VTE and treatment-associated bleeding, which are characterized by the presence of endogenous factors (such as hereditary thrombophilic disorders), but much more by exogenous factors (underlying disease). This results in risk-adapted therapeutic recommendations, which will be discussed in the following review.

Influence of Cyclosporin A on human gingival keratinocytes in vitro.

Purpose: Gingival hyperplasia is a well known side effect of Cyclosporine A therapy. The aetiology of this is not totally understood and there is debate whether it is hyperplasia of the gingival epithelium or of the submucosal connective tissue, or both, and what roles play factors like age and gender of the patients, duration and dosage of the drug.

Material And Methods: The influence of different Cyclosporine A concentrations (10(-6) g/ml; 5 x 10(-7) g/ml; 10(-9) g/ml) and of no medication (controls) on growth and proliferation of cultured human gingival keratinocytes was investigated after a culture period of 3, 6 and 9 days.

Deep vein thrombosis: Current diagnostic strategy.

Over the last 15 years, diagnostic strategies to diagnose deep vein thrombosis (DVT) and pulmonary embolism (PE) have changed significantly. The gold standard for detecting DVT is still venography, but invasivity, radiation, contrast media, and the painful injection in pedal veins are limiting factors for initial and repeat examinations. The introduction of DVT scores, D-dimer testing, and venous ultrasound has made venography replaceable in most cases.

How optimal life history changes with the community size-spectrum.

This paper derives optimal life histories for fishes or other animals in relation to the size spectrum of the ecological community in which they are both predators and prey. Assuming log-linear size-spectra and well known scaling laws for feeding and mortality, we first construct the energetics of the individual. From these we find, using dynamic programming, the optimal allocation of energy between growth and reproduction as well as the trade-off between offspring size and numbers.

[Deep venous thrombosis and pulmonary embolism. Prophylaxis and therapy].

Venous thromboembolism is a common cause of morbidity and mortality with an estimated annual incidence of 1:1,000. Several patient groups at risk can be differentiated, according to the presence of endogenous factors (such as hereditary thrombophilic disorders), but much more by exogenous factors (underlying disease). This results in risk-adapted recommendations for prophylaxis and therapy, which will be discussed in the following overview.

Venous thrombosis after long-haul flights.

Background: The risk for venous thromboembolism after long-haul flights represents a controversial issue. The aim of our study was to assess the incidence of venous thrombosis associated with long-haul flights in a prospective, controlled cohort study.

Methods: We included 964 passengers returning from long-haul flights (flight duration, > or =8 hours) and 1213 nontraveling control subjects.

Complete compression ultrasonography of the leg veins as a single test for the diagnosis of deep vein thrombosis.

Noninvasive diagnosis of deep vein thrombosis (DVT) is based on ultrasound examination of the leg veins, usually restricted to only compression of the proximal veins (CUS). Patients with negative CUS findings require a second examination or a combination with other tests, which impairs clinical efficiency. In this prospective outcome study, 1646 consecutive patients with clinically suspected DVT were examined once by a standardized protocol of complete compression ultrasound comprising all proximal and distal veins (CCUS) as the only diagnostic test.