Frequency conversion in a hydrogen-filled hollow-core fiber using continuous-wave fields.

In large-area quantum networks based on optical fibers, photons are the fundamental carriers of information as so-called flying qubits. They may also serve as the interconnect between different components of a hybrid architecture, which might comprise atomic and solid-state platforms operating at visible or near-infrared wavelengths, as well as optical links in the telecom band. Quantum frequency conversion is the pathway to change the color of a single photon while preserving its quantum state.

Universal relation between the conditional auto-correlation function and the cross-correlation function of biphotons.

We systematically studied the relation between the conditional auto-correlation function (CACF) and cross-correlation function (CCF) of biphotons or pairs of single photons. The biphotons were generated from a heated atomic vapor via the spontaneous four-wave mixing (SFWM) process. In practical usage, one single photon of a pair is utilized as the heralding photon, and another is employed as the heralded photon.

Single-photon-level narrowband memory in a hollow-core photonic bandgap fiber.

An experimental platform operating at the level of individual quanta and providing strong light-matter coupling is a key requirement for quantum information processing. In our work, we show that hollow-core photonic bandgap fibers filled with laser-cooled atoms might serve as such a platform, despite their typical complicated birefringence properties. To this end, we present a detailed theoretical and experimental study to identify a fiber with suitable properties to achieve operation at the single-photon level.

Accounting for multiple ecosystem services in a simulation of land-use decisions: Does it reduce tropical deforestation?

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decision-making. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests.

The Impact of Integrin β2 on Granulocyte/Macrophage Progenitor Proliferation.

Previously, we reported that although the HSPC frequency in bone marrow cells (BMC) was comparable between β2-/- and β2+/+ mice, transplantation of β2-/- BMC into lethally irradiated CD45.1 recipient resulted in more myeloid cell production than β2+/+ BMC. The objective of this study is to address if integrin β2 deficiency skews granulocyte/macrophage progenitor (GMP) proliferation.

S1-Leitlinie zur UV-Phototherapie und Photochemotherapie.

Die heilsame Wirkung des Sonnenlichts war teilweise schon im Altertum bekannt und fand in der zweiten Hälfte des 19. Jahrhunderts wieder zunehmend Beachtung. Den Beginn der modernen Phototherapien markiert die Entwicklung einer Apparatur zur ultravioletten Bestrahlung der Hauttuberkulose durch Finnsen zu Beginn des zwanzigsten Jahrhunderts.

S1-Guidelines on UV phototherapy and photochemotherapy.

Known in part since antiquity, the salutary effects of sunlight again garnered increasing attention in the second half of the 19(th) century. The development of a device for ultraviolet irradiation of cutaneous tuberculosis by Finnsen at the onset of the twentieth century truly marked the beginning of modern phototherapy. In dermatology, treatment methods almost exclusively use wavelengths below the visible light range (ultraviolet light).

Hematopoietic stem/progenitor cells directly contribute to arteriosclerotic progression via integrin β2.

Recent studies described the association between hematopoietic stem/progenitor cell (HSPC) expansion in the bone marrow (BM), leukocytosis in the peripheral blood, and accelerated atherosclerosis. We hypothesized that circulating HSPC may home to inflamed vessels, where they might contribute to inflammation and neointima formation. We demonstrated that Lin(-) Sca-1(+) cKit(+) (LSK cells) in BM and peripheral blood of LDLr(-/-) mice on high fat diet expressed significantly more integrin β2 , which was responsible for LSK cell adhesion and migration toward ICAM-1 in vitro, and homing to injured arteries in vivo, all of which were blocked with an anti-CD18 blocking antibody.

An ecological paradox: high species diversity and low position of the upper forest line in the Andean Depression.

Systematic investigations of the upper forest line (UFL) primarily concentrate on mid and high latitudes of the Northern Hemisphere, whereas studies of Neotropical UFLs are still fragmentary. This article outlines the extraordinary high tree diversity at the UFL within the Andean Depression and unravels the links between the comparatively low position of the local UFL, high tree-species diversity, and climate. On the basis of Gentry's rapid inventory methodology for the tropics, vegetation sampling was conducted at 12 UFL sites, and local climate (temperature, wind, precipitation, and soil moisture) was investigated at six sites.

β2 integrin mediates hantavirus-induced release of neutrophil extracellular traps.

Rodent-borne hantaviruses are emerging human pathogens that cause severe human disease. The underlying mechanisms are not well understood, as hantaviruses replicate in endothelial and epithelial cells without causing any cytopathic effect. We demonstrate that hantaviruses strongly stimulated neutrophils to release neutrophil extracellular traps (NETs).

One-dimensional ultracold medium of extreme optical depth.

We report on the preparation of a one-dimensional ultracold medium in a hollow-core photonic crystal fiber, reaching an effective optical depth of 1000(150). We achieved this extreme optical depth by transferring atoms from a magneto-optical trap into a far-detuned optical dipole trap inside the hollow-core fiber, yielding up to 2.5(3)×10(5) atoms inside the core with a loading efficiency of 2.

Reduction of CD18 promotes expansion of inflammatory γδ T cells collaborating with CD4+ T cells in chronic murine psoriasiform dermatitis.

IL-17 is a critical factor in the pathogenesis of psoriasis and other inflammatory diseases. The impact of γδ T cells, accounting for an important source of IL-17 in acute murine IL-23- and imiquimod-induced skin inflammation, in human psoriasis is still unclear. Using the polygenic CD18(hypo) PL/J psoriasis mouse model spontaneously developing chronic psoriasiform dermatitis due to reduced CD18/β2 integrin expression to 2-16% of wild-type levels, we investigated in this study the influence of adhesion molecule expression on generation of inflammatory γδ T cells and analyzed the occurrence of IL-17-producing γδ and CD4(+) T cells at different disease stages.

Reduced CD18 levels drive regulatory T cell conversion into Th17 cells in the CD18hypo PL/J mouse model of psoriasis.

Defective development and function of CD4(+)CD25(high+)Foxp3(+) regulatory T cells (Tregs) contribute to the pathogenesis of psoriasis and other autoimmune diseases. Little is known about the influence of adhesions molecules on the differentiation of Foxp3(+) Tregs into proinflammatory Th17 cells occurring in lesional skin and blood of psoriasis patients. In the CD18(hypo) PL/J mouse model of psoriasis, reduced expression of CD18/β2 integrin to 2-16% of wild-type levels is associated with progressive loss of Tregs, impaired cell-cell contact between Tregs and dendritic cells (DCs), as well as Treg dysfunction as reported earlier.

Variable ultrabroadband and narrowband composite polarization retarders.

We propose and experimentally demonstrate novel types of composite sequences of half-wave and quarter-wave polarization retarders, permitting operation at either ultrabroad spectral bandwidth or narrow bandwidth. The retarders are composed of stacked standard half-wave retarders and quarter-wave retarders of equal thickness. To our knowledge, these home-built devices outperform all commercially available compound retarders, made of several birefringent materials.

Adaptive immune response to model antigens is impaired in murine leukocyte-adhesion deficiency-1 revealing elevated activation thresholds in vivo.

Absence of β₂ integrins (CD11/CD18) leads to leukocyte-adhesion deficiency-1 (LAD1), a rare primary immunodeficiency syndrome. Although extensive in vitro work has established an essential function of β₂ integrins in adhesive and signaling properties for cells of the innate and adaptive immune system, their respective participation in an altered adaptive immunity in LAD1 patients are complex and only partly understood in vivo. Therefore, we investigated adaptive immune responses towards different T-dependent antigens in a murine LAD1 model of β₂ integrin-deficiency (CD18⁻/⁻).

Highly efficient broadband conversion of light polarization by composite retarders.

Driving on an analogy with the technique of composite pulses in quantum physics, we propose highly efficient broadband polarization converters composed of sequences of ordinary retarders rotated at specific angles with respect to their fast-polarization axes.

An unrestrained proinflammatory M1 macrophage population induced by iron impairs wound healing in humans and mice.

Uncontrolled macrophage activation is now considered to be a critical event in the pathogenesis of chronic inflammatory diseases such as atherosclerosis, multiple sclerosis, and chronic venous leg ulcers. However, it is still unclear which environmental cues induce persistent activation of macrophages in vivo and how macrophage-derived effector molecules maintain chronic inflammation and affect resident fibroblasts essential for tissue homeostasis and repair. We used a complementary approach studying human subjects with chronic venous leg ulcers, a model disease for macrophage-driven chronic inflammation, while establishing a mouse model closely reflecting its pathogenesis.

Observation of phase variation within stationary light pulses inside a cold atomic medium.

The successful formation of stationary light pulses in a cold atomic medium was demonstrated recently. However, unlike in hot media, a detuning between the counterpropagating fields had to be applied. Here we demonstrate that a significant nonuniform phase variation can be induced during a period of stationary light owing to off-resonantly driven transitions.

LFA-1 contributes to signal I of T-cell activation and to the production of T(h)1 cytokines.

The beta(2) integrins are important for both transendothelial migration of leukocytes and T-cell activation during antigen presentation. In T cells, triggering of leukocyte functional antigen-1 (LFA-1) is required for full activation and T-helper (Th)1/Th2 differentiation. We used CD18-deficient (CD18(-/-)) mice to examine the role of LFA-1 in the activation of T cells.

Extracellular adherence protein of Staphylococcus aureus suppresses disease by inhibiting T-cell recruitment in a mouse model of psoriasis.

Psoriasis is a T-cell-mediated inflammatory disease. Previous studies focused on lymphocyte function-associated antigen 1 (LFA-1)-expressing T cells as a molecular target for therapeutic intervention. By contrast, information on therapeutic effects and the underlying mechanism of blocking the LFA-1 counter receptor, ICAM-1 is scarce.

Beta(2) integrin deficiency yields unconventional double-negative T cells distinct from mature classical natural killer T cells in mice.

Expressed on leucocytes, beta(2) integrins (CD11/CD18) are specifically involved in leucocyte function. Using a CD18-deficient (CD18(-/-)) mouse model, we here report on their physiological role in lymphocyte differentiation and trafficking. CD18(-/-) mice present with a defect in the distribution of lymphocytes with highly reduced numbers of naïve B and T lymphocytes in inguinal and axillary lymph nodes.