Rydberg Excitons in the Presence of an Ultralow-Density Electron-Hole Plasma.

We study the Rydberg exciton absorption of Cu_{2}O in the presence of free carriers injected by above-band-gap illumination. Already at plasma densities ρ_{EH} below one hundredth electron-hole pair per µm^{3}, exciton lines are bleached, starting from the highest observed principal quantum number, while their energies remain constant. Simultaneously, the band gap decreases by correlation effects with the plasma. An exciton line loses oscillator strength when the band gap approaches its energy, vanishing completely at the crossing point. Adapting a plasma-physics description, we describe the observations by an effective Bohr radius that increases with rising plasma density, reflecting the Coulomb interaction screening by the plasma.

Long-term reduction of seclusion and forced medication on a hospital-wide level: Implementation of an open-door policy over 6 years.

BACKGROUND: Psychiatric inpatient treatment is increasingly performed in settings with locked doors. However, locked wards have well-known disadvantages and are ethically problematic. In addition, recent data challenges the hypothesis that locked wards provide improved safety over open-door settings regarding suicide, absconding and aggression. Furthermore, there is evidence that the introduction of an open-door policy may lead to short-term reductions in involuntary measures. The aim of this study was to assess if the introduction of an open-door policy is associated with a long-term reduction of the frequency of seclusion and forced medication. METHOD: In this 6-year, hospital-wide, longitudinal, observational study, we examined the frequency of seclusion and forced medication in 17,359 inpatient cases admitted to the Department of Adult Psychiatry, Universitäre Psychiatrische Kliniken (UPK) Basel, University of Basel, Switzerland. In an approach to enable a less restrictive policy, six previously closed psychiatric wards were permanently opened beginning from August 2011. During this process, a systematic change towards a more patient-centered and recovery-oriented care was applied. Statistical analysis consisted of generalized estimating equations (GEE) models. RESULTS: In multivariate analyses controlling for potential confounders, the implementation of an open-door policy was associated with a continuous reduction of seclusion (from 8.2 to 3.5%; ηp2=0.82; odds ratio: 0.88) and forced medication (from 2.4 to 1.2%; ηp2=0.70; odds ratio: 0.90). CONCLUSION: This underlines the potential of the introduction of an open-door policy to attain a long-term reduction in involuntary measures.

Synthesis of M-UiO-66 (M = Zr, Ce or Hf) employing 2,5-pyridinedicarboxylic acid as a linker: defect chemistry, framework hydrophilisation and sorption properties.

Metal-organic frameworks of general composition [M6(OH)4(O)4(PDC)6-x(Cl)2x(H2O)2x] with M = Zr, Ce, Hf; PDC2- = 2,5-pyridinedicarboxylate and 0 ≤ x ≤ 2 were obtained under reflux using formic, nitric or acetic acid as an additive. Rietveld refinements carried out using a fixed occupancy of the linker molecules according to the results of thermogravimetric measurements confirmed that the MOFs crystallize in the UiO-66 type structure and demonstrate that the structural models describe the data well. Further characterization was carried out by NMR spectroscopy, thermogravimetric analysis, Zr K-edge EXAFS- and Ce L3-edge XANES measurements. To highlight the influence of the additional nitrogen atom of the pyridine ring, luminescence and vapour sorption measurements were carried out. The hydrophilisation of the MOFs was shown by the adsorption of water at lower p/p0 (<0.2) values compared to the corresponding BDC-MOFs (0.3). For water and methanol stability cycling adsorption experiments were carried out to evaluate the MOFs as potential adsorbents in heat transformation applications.

Signatures of Quantum Coherences in Rydberg Excitons.

Coherent optical control of individual particles has been demonstrated both for atoms and semiconductor quantum dots. Here we demonstrate the emergence of quantum coherent effects in semiconductor Rydberg excitons in bulk Cu_{2}O. Because of the spectral proximity between two adjacent Rydberg exciton states, a single-frequency laser may pump both resonances with little dissipation from the detuning. As a consequence, additional resonances appear in the absorption spectrum that correspond to dressed states consisting of two Rydberg exciton levels coupled to the excitonic vacuum, forming a V-type three-level system, but driven only by one laser light source. We show that the level of pure dephasing in this system is extremely low. These observations are a crucial step towards coherently controlled quantum technologies in a bulk semiconductor.

Observation of High Angular Momentum Excitons in Cuprous Oxide.

The recent observation of dipole-allowed P excitons up to principal quantum numbers of n=25 in cuprous oxide has given insight into exciton states with unprecedented spectral resolution. While so far the exciton description as a hydrogenlike complex has been fully adequate for cubic crystals, we demonstrate here distinct deviations: The breaking of rotational symmetry leads to mixing of high angular momentum F and H excitons with the P excitons so that they can be observed in absorption. The F excitons show a threefold splitting that depends systematically on n, in agreement with theoretical considerations. From detailed comparison of experiment and theory we determine the cubic anisotropy parameter of the Cu(2)O valence band.

Giant Rydberg excitons in the copper oxide Cu2O.

A highly excited atom having an electron that has moved into a level with large principal quantum number is a hydrogen-like object, termed a Rydberg atom. The giant size of Rydberg atoms leads to huge interaction effects. Monitoring these interactions has provided insights into atomic and molecular physics on the single-quantum level. Excitons--the fundamental optical excitations in semiconductors, consisting of an electron and a positively charged hole--are the condensed-matter analogues of hydrogen. Highly excited excitons with extensions similar to those of Rydberg atoms are of interest because they can be placed and moved in a crystal with high precision using microscopic energy potential landscapes. The interaction of such Rydberg excitons may allow the formation of ordered exciton phases or the sensing of elementary excitations in their surroundings on a quantum level. Here we demonstrate the existence of Rydberg excitons in the copper oxide Cu2O, with principal quantum numbers as large as n = 25. These states have giant wavefunction extensions (that is, the average distance between the electron and the hole) of more than two micrometres, compared to about a nanometre for the ground state. The strong dipole-dipole interaction between such excitons is indicated by a blockade effect in which the presence of one exciton prevents the excitation of another in its vicinity.

The role of Nrf2 in increased reactive oxygen species and DNA damage in prostate tumorigenesis.

The impact of oxidative stress in human cancer has been extensively studied. It is accepted that elevated reactive oxygen species (ROS) promote mutagenic DNA damage. Even with an extensive armament of cellular antioxidants and detoxification enzymes, alterations to DNA occur that initiate cellular transformation. Erythroid 2p45 (NF-E2)-related factor 2 (Nrf2) is a basic-region leucine zipper transcription factor that mediates the expression of key protective enzymes through the antioxidant-response element (ARE). By analysing 10 human prostate cancer microarray data sets, we have determined that Nrf2 and members of the glutathione-S-transferase (GST) mu family are extensively decreased in human prostate cancer. Using the TRAMP transgene and Rb and Nrf2 knockout murine models, we demonstrated that the loss of Nrf2 initiates a detrimental cascade of reduced GST expression, elevated ROS levels and ultimately DNA damage associated with tumorigenesis. Based on overwhelming data from clinical samples and the current functional analysis, we propose that the disruption of the Nrf2-antioxidant axis leads to increased oxidative stress and DNA damage in the initiation of cellular transformation in the prostate gland.

Functional and phenotypic changes in polymorphonuclear neutrophils induced by catecholamines.

PURPOSE: To elucidate differential functional and phenotypic changes in response to relevant catecholamines, the generation of oxidative free radicals by PMN, and changes in the expression of L-selectin and Mac-1 on the surface of PMN were examined in the presence of epinephrine, norepinephrine and dopamine in physiological and pharmacological concentrations. MATERIALS AND METHODS: Human polymorphonuclear neutrophils were obtained from healthy donors and pretreated with 0.5 nM or 500 nM epinephrine; 1.18 nM or 1 180 nM norepinephrine; or 0.26 nM or 261 nM dopamine, followed by stimulation with FMLP. Stimulated neutrophils were incubated with antibodies against CD 11 b or CD 62 l and assessed by flow cytometry. Additional probes were assessed by flow cytometry for the generation of oxidative free radicals. RESULTS: All catecholamines in high concentration inhibited the suppression of CD 62 l expression and CD 11 b upregulation following stimulation with FMLP. A high concentration of epinephrine suppresses generation of oxidative free radicals. CONCLUSIONS: The effect of catecholamines on the expression of CD 62 l explains the increased expression of L-selection on PMN observed after trauma. The suppression of CD 11 b reduces leukocyte adherence and consecutive abnormalities in microvascular flow. Epinephrine inhibits the generation of oxidative free radicals by PMN with potentially detrimental effects with respect to bacterial clearance.

Synthetic inotropes inhibit the expression of adhesion molecules and augment the expression of L-selectin in polymorphonuclear neutrophils.

OBJECTIVES: To elucidate differential functional and phenotypic changes in response to clinically relevant synthetic inotropes plus the generation of oxidative free radicals by polymorphonuclear neutrophils (PMN), and changes in the expression of L-selectin and Mac-1 on the surface of PMN were examined in the presence of dobutamine and dopexamine in pharmacological concentrations. DESIGN: Prospective, in vitro study. SETTING: Research laboratory. SUBJECTS: Human PMN obtained from healthy donors. INTERVENTIONS: PMN were pretreated with dobutamine 147.99 nM or 147,990 nM, or dopexamine 100 nM or 100,000 nM, followed by stimulation with FMLP. Stimulated neutrophils were incubated with antibiodies against CD11b or CD62l and assessed by flow cytometry. Additional probes were assessed by flow cytometry for the generation of oxidative free radicals. MEASUREMENTS AND MAIN RESULTS: Low concentrations of both synthetic inotropes significantly inhibit the suppression of CD62l expression following stimulation with N-formyl-l-methionyl-l-leucyl-l-phenylalanine; high concentrations antagonize this effect. High concentrations of both synthetic inotropes suppresses the expression of CD11b. Neither dobutamine nor dopexamine modified the generation of oxidative free radicals. CONCLUSIONS: While the upregulation of Mac-1 expression is inhibited in a dose-dependent manner, the expression of L-selectin is enhanced at low concentrations of dobutamine and dopexamine and partly counter-regulated at high concentrations. It seems that synthetic inotropes can modulate the immunomodulatory ability by inhibition of PMN rolling and modification of PMN adherence and diapedese.

Inhibition of the neutrophil oxidative response by propofol: preserved in vivo function despite in vitro inhibition.

BACKGROUND AND OBJECTIVE: Propofol has been shown to inhibit a variety of functions of neutrophils in vitro, but there is a lack of in vivo data. To analyse the effects of propofol on neutrophil function in vivo we chose to investigate cataract surgery since it represents a small surgical procedure with minimal immunomodulatory effects induced by surgery. We sought to analyse any immunosuppressive effects of propofol after short-term administration in vivo in comparison to local anaesthesia as well as to in vitro effects of propofol. METHODS: The study was designed as an open randomized trial enrolling 20 patients undergoing general or local anaesthesia. The neutrophil oxidative response and propofol plasma concentration were assessed prior, during and after anaesthesia. Neutrophil function was determined flow cytometrically based on dihydrorhodamine 123 oxidation. RESULTS: Propofol concentrations which yielded a marked suppression in vitro did not alter the neutrophil oxidative response during cataract surgery in vivo. However, after local anaesthesia the neutrophil oxidative response declined to 37%, compared to the control response prior to anaesthesia. CONCLUSIONS: Although we could detect the well established suppression of neutrophil function by propofol in vitro it was not evident in vivo. This may be due to compensating effects on neutrophil function during surgery in vivo. The decline in the neutrophil oxidative response in the local anaesthesia group might be due to increased stress and catecholamine concentrations or a direct interaction of local anaesthetics with neutrophil intracellular signalling.

Bemisia argentifolii is a race of B. tabaci (Hemiptera: Aleyrodidae): the molecular genetic differentiation of B. tabaci populations around the world.

The phylogenetic relationships between genotypes of Bemisia tabaci were compared using ITS1 and CO1 nucleotide sequences. Phylogenetic and minimum spanning network analyses identified six major races, Asia, Bali, Australia, sub-Saharan Africa, Mediterranean/Asia Minor/Africa and New World as well as a large collection of genotypes from the Asia region with no strong association with any of the races. The term race is based on its usage in Mallet (2001). Mating incompatibility occurs between some races. There is insufficient data to raise races to species status, but the data supports the recognition of the six races and an unresolved core of ungrouped genotypes under the single Bemisia tabaci (Gennadius) species name. To clarify the identity of the race to which the B. tabaci under investigation is known, the following nomenclature is suggested, B. tabaci (Asia), B. tabaci (Bali), B. tabaci (Australia) B. tabaci (sub-Saharan Africa), B. tabaci (Mediterranean/Asia Minor/Africa) and B. tabaci (New World). Further, there is insufficient molecular or biological data to support the separation of B. tabaci and B. argentifolii Bellows & Perring and its use should be discontinued.

Cerebrospinal fluid and neutrophil respiratory burst after subarachnoid hemorrhage.

OBJECTIVES: To investigate the effect of cerebrospinal fluid (CSF) from patients with subarachnoid hemorrhage (SAH) on the activation of polymorphonuclear neutrophils (PMN) in response to receptor-dependent stimulation with N-formyl-l-methionyl-l-leucyl-l-phenylalanine and TNFalpha or non-receptor-dependent stimulation with phorbol 12-myristate 13-acetate. METHODS: CSF from 12 patients with SAH due to ruptured cerebral aneurysm was collected. Samples of CSF were drawn at different time points. CSF from 6 healthy subjects receiving spinal anesthesia served as the control group. After stimulation of PMN the generation of reactive oxygen intermediates was analyzed on a flow cytometer. RESULTS: In the presence of CSF, PMN showed a significant suppression of the oxidative burst following stimulation compared to stimulation without CSF. The reduction of the oxidative burst following stimulation was higher in the presence of CSF from patients with SAH. After pretreatment at 56 degrees C, the extent of the suppression observed following receptor-dependent stimulation and CSF from patients with SAH was similar to that seen after stimulation with CSF from healthy individuals. CONCLUSIONS: These data show that the presence of CSF resulted in a suppression of neutrophil oxidative function. A more distinct depression was seen in the presence of CSF from patients with SAH. We suggest a complex physiological inhibitory and protective mechanism against unfavorable activation of PMN by CSF.

Thiopentone and methohexitone enantiomers do not act stereoselectively on the oxidative response in human neutrophils in vitro.

To elucidate potential stereoselective effects of single barbiturate isomers, we compared the inhibitory potency of single thiopentone enantiomers, two isomer-enriched mixtures of methohexitone and racemic mixtures of both barbiturates on the fMLP-induced neutrophil oxidative response. A suppression of the response to 50% compared to control required a 100-fold therapeutic concentration of methohexitone, while therapeutic concentrations of the thiopentone racemate led to a significant inhibition (relative fluorescence of neutrophils 0.46 +/- 0.03 compared to fMLP controls). The racemate of thiopentone produced significantly greater inhibition than the single enantiomers. Stereoselectivity in favor of one isomer could not be shown for both barbiturates. The greater inhibition by the thiopentone racemate might suggest two separate binding sites for the enantiomers which are positively coupled.

Cytokine upregulation of surface antigens correlates to the priming of the neutrophil oxidative burst response.

BACKGROUND: Neutrophil activation is strongly related to organ dysfunction that occurs during systemic inflammatory responses. The aim of our study was to analyze the oxidative burst response in correlation to the up- and downregulation of N-formyl-L-methionyl-L-leucyl-phenylalanine (fMLP) receptors and the surface antigens CD11b, CD62L, and CD66b as potential surrogate markers of the degree of neutrophil priming for an increased oxidative burst response induced by proinflammatory cytokines. METHODS: Blood was taken from healthy donors. Neutrophils were pretreated with cytokines (interleukin [IL]-1beta, IL-6, IL-8, granulocyte-macrophage colony-stimulating factor [GM-CSF], and tumor necrosis factor alpha [TNFalpha]; 0.01-10 ng/ml) and stimulated with fMLP (100 nM) in vitro. Functional and phenotypical parameters were quantified flow cytometrically. RESULTS: The oxidative burst response increased after priming with 0.1 ng/ml TNFalpha, 1 ng/ml GM-CSF, or 10 ng/ml IL-8. Upregulation of fMLP receptors, CD11b, and CD66b and downregulation of CD62L showed a close correlation to the oxidative burst response. Altered expression of these parameters partly reached significance at lower cytokine concentrations in comparison with the oxidative burst. IL-1beta and IL-6 had no effect. CONCLUSIONS: Our results showed that the expression of phenotypical parameters closely correlates with functional parameters in human neutrophils. Thus an up- or downregulation of antigens such as CD11b or CD62L reflects cytokine-induced functional changes.

Wave-vector-dependent exciton exchange interaction.

The exchange interaction for the yellow 1S orthoexciton in Cu2O is derived up to the order K2. The resulting exchange splittings are verified experimentally using high resolution spectroscopy. In agreement with theory the fine structure shows a characteristic dependence on the direction of the wave vector.

[Status of essential trace elements in untreated carcinomas of the head and neck]. / Status essenzieller Spurenelemente bei unbehandelten Kopf-Hals-Karzinomen.

BACKGROUND: The changed mineral status is well known in different tumor types. This phenomenon has influenced the redox potential of patients suffering from solid cancers. A prospective trial was conducted to evaluate the specifics for untreated head and neck cancer patients. MATERIAL AND METHODS: We included 100 patients with advanced squamous cell carcinoma of the head and neck region before each kind of treatment. Following serum-concentrations were measured by atom absorption spectrometry: selenium, copper, zinc, and ferrum. Additionally we evaluated the activity of glutathion peroxidase and the concentration of malondialdehyde of the serum. RESULTS: 66 % of all patients have shown a decreased serum-concentration of selenium. These patients were additionally characterized by decreased activities of endogenous glutathionperoxiase. A third of all patients had decreased zinc and iron levels. Copper was found enhanced in 30 %. In trend the malondialdehyde was increasing due to decreasing selenium levels. CONCLUSIONS: Head neck cancer patients show the same characteristic trace element status as other solid tumors: decreased selenium, zinc and iron, increased copper. The therapeutic consequences of these observations are still unclear.

Observation of coupled magnetic and electric domains.

Ferroelectromagnets are an interesting group of compounds that complement purely (anti-)ferroelectric or (anti-)ferromagnetic materials--they display simultaneous electric and magnetic order. With this coexistence they supplement materials in which magnetization can be induced by an electric field and electrical polarization by a magnetic field, a property which is termed the magnetoelectric effect. Aside from its fundamental importance, the mutual control of electric and magnetic properties is of significant interest for applications in magnetic storage media and 'spintronics'. The coupled electric and magnetic ordering in ferroelectromagnets is accompanied by the formation of domains and domain walls. However, such a cross-correlation between magnetic and electric domains has so far not been observed. Here we report spatial maps of coupled antiferromagnetic and ferroelectric domains in YMnO3, obtained by imaging with optical second harmonic generation. The coupling originates from an interaction between magnetic and electric domain walls, which leads to a configuration that is dominated by the ferroelectromagnetic product of the order parameters.

["Simplified Acute Physiology Score" (SAPS II) ina the assessment of severity of illness in surgical intensive care patients]. / "Simplified Acute Physiology Score" (SAPS II) zur Einschätzung der Erkrankungsschwere bei chirurgischen Intensivpatienten.

INTRODUCTION: In 1993, Le Gall proposed a new Simplified Acute Physiology Score (SAPS II) to assess the severity of illness in intensive care patients and to predict the risk of hospital mortality using a large data base of more than 13,000 patients of different intensive care units. Up to the present time, no satisfactory form of validation for surgical intensive care patients has been available. We investigated the prognostic quality of this score system for the assessment of the severity of the illness in surgical intensive care patients. METHODS: Between October 1997 and December 1998, 310 consecutive patients were included in our study. We calculated the SAPS II score according to the published guidelines. Additionally, we calculated the risk of mortality by referring to the score. We used a receiver operating characteristics (ROC) analysis for statistical evaluation. RESULTS: The median duration of stay on our intensive care unit was 8.4 days. In all patients, the mean SAPS II was 29.9 +/- 12.7. In the survivors, calculation of mean SAPS II was 27.7 +/- 11.4. In the non-survivors, mean SAPS II was 45.7 +/- 11.2. The predicted risk of mortality was 15.7%, the actual risk of mortality was 15.8%. CONCLUSION: The SAPS II score has proved to be a good prognostic instrument in surgical intensive care patients. SAPS II is particularly effective in providing an exact estimation of the risk of death, classifying patient groups in clinical studies, epidemiological investigations, and quality assessment.

Thiopental impairs neutrophil oxidative response by inhibition of intracellular signalling.

BACKGROUND AND OBJECTIVE: Thiopental in clinically relevant concentrations inhibits the oxidative function of neutrophils, whereas only very high, non-therapeutic concentrations of methohexital induce a similar effect. The study characterized the molecular basis of this differential action of oxy- and thiobarbiturates on neutrophils. METHODS: Neutrophils were incubated in vitro with thiopental or methohexital using concentrations within the therapeutic range. Neutrophil responses were induced using different stimuli: N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), C5a and 1,2-dioctanoyl-sn-glycerol (DiC8-DAG). FMLP and C5a bind to specific G-protein-coupled receptors that share the same second messenger cascade. In contrast, DiC8-DAG, an activator of protein kinase C, bypasses the signal transduction pathway downstream of the receptors. Hydrogen peroxide production by neutrophils was assessed using flow cytometry. To characterize the localization of the interaction site, FMLP receptor expression and cytosolic-free calcium were further analysed. RESULTS: FMLP and C5a-induced hydrogen peroxide production were both significantly impaired by thiopental, but not by methohexital. When postreceptor signalling was bypassed, by stimulation with DiC8-DAG, neither thiopental nor methohexital affected hydrogen peroxide production. Additionally, neither of the barbiturates impaired the cytosolic Ca2+ response. CONCLUSIONS: We conclude that neither protein kinase C nor the hydrogen peroxide-generating enzymes are affected by thiopental or methohexital. The unimpaired Ca2+ response suggests that the function of the receptors and G-proteins were also unimpaired. Taken together, this indicates that the site of action of thiopental is in the cellular signalling upstream of protein kinase C.

Second harmonic generation in the centrosymmetric antiferromagnet NiO.

In spite of the fact that inversion is a symmetry operation of both the crystalline and the magnetic lattice of NiO, second harmonic generation (SHG) has been observed below the Néel temperature. A spectroscopic study shows that the signal is due to combined magnetic-dipole and electric-dipole transitions between the (3d)(8) levels of the Ni(2+) ion in the crystal field. The SHG is resonant in both the incoming and the outgoing light waves and thus greatly enhanced. A quadratic coupling of the nonlinear polarization to the order parameter was found. This allows the investigation of individual domains.