High erythroferrone expression in CD71+ erythroid progenitors predicts superior survival in myelodysplastic syndromes

Ineffective erythropoiesis and iron overload are common in myelodysplastic syndromes (MDS). Erythroferrone (ERFE) and growth/differentiation factor 15 (GDF15) are two regulators of iron homeostasis produced by erythroid progenitors. Elevated systemic levels of ERFE and GDF15 in MDS are associated with dysregulated iron metabolism and iron overload, which is especially pronounced in MDS with SF3B1 gene mutations. However, the role of ERFE and GDF15 in MDS pathogenesis and their influence on disease progression are largely unknown. Here, we analyzed the expression of ERFE and GDF15 in CD71⁺ erythroid progenitors of n = 111 MDS patients and assessed their effects on patient survival. The expression of ERFE and GDF15 in MDS was highly aberrant. Unexpectedly, ERFE expression in erythroprogenitors was highly relevant for MDS prognosis and independent of International Prognostic Scoring System (IPSS) stratification. Although ERFE expression was increased in patients with SF3B1 mutations, it predicted overall survival (OS) in both the SF3B1wt and SF3B1mut subgroups. Of note, ERFE overexpression predicted superior OS in the IPSS low/Int-1 subgroup and in patients with normal karyotype. Similar observations were made for GDF15, albeit not reaching statistical significance. In summary, our results revealed a strong association between ERFE expression and MDS outcome, suggesting a possible involvement of ERFE in molecular MDS pathogenesis.

Local Electrical Imaging of Tetragonal Domains and Field-Induced Ferroelectric Twin Walls in Conducting SrTiO_{3}

We demonstrate electrical mapping of tetragonal domains and electric field-induced twin walls in SrTiO_{3} as a function of temperature and gate bias utilizing the conducting LaAlO_{3}/SrTiO_{3} interface and low-temperature scanning electron microscopy. Conducting twin walls appear below 105 K, and new twin patterns are observed after thermal cycling through the transition or on electric field gating. The nature of the twin walls is confirmed by calculating their intersection angles for different substrate orientations. Numerous walls formed when a large side- or back-gate voltage is applied are identified as field-induced ferroelectric twin walls in the paraelectric tetragonal matrix. The walls persist after switching off the electric field and on thermal cycling below 105 K. These observations point to a new type of ferroelectric functionality in SrTiO_{3}, which could be exploited together with magnetism and superconductivity in a multifunctional context.

Structural and Electronic Properties of Nitrogen-Doped Graphene

We investigate the structural and electronic properties of nitrogen-doped epitaxial monolayer graphene and quasifreestanding monolayer graphene on 6H-SiC(0001) by the normal incidence x-ray standing wave technique and by angle-resolved photoelectron spectroscopy supported by density functional theory simulations. With the location of various nitrogen species uniquely identified, we observe that for the same doping procedure, the graphene support, consisting of substrate and interface, strongly influences the structural as well as the electronic properties of the resulting doped graphene layer. Compared to epitaxial graphene, quasifreestanding graphene is found to contain fewer nitrogen dopants. However, this lack of dopants is compensated by the proximity of nitrogen atoms at the interface that yield a similar number of charge carriers in graphene.

High responsivity GaNAsSb p-i-n photodetectors at 1.3 microm grown by radio-frequency nitrogen plasma-assisted molecular beam epitaxy

GaNAsSb/GaAs p-i-n photo notdetectors with an intrinsic GaNAsSb photoabsorption layer grown at 350 degrees C, 400 degrees C, 440 degrees C and 480 degrees C, have been prepared using radio-frequency nitrogen plasma-assisted molecular beam epitaxy in conjunction with a valved antimony cracker source. The i-GaNAsSb photoabsorption layer contains 3.3% of nitrogen and 8% of antimony, resulting in DC photo-response up to wavelengths of 1350 nm. The device with i-GaNAsSb layer grown at 350 degrees C exhibits extremely high photoresponsivity of 12A/W at 1.3 microm. These photodetectors show characteristics which strongly suggest the presence of carrier avalanche process at reverse bias less than 5V.

Platypnoe-Orthodeoxie-Syndrom einer 69-j�hrigen Patientin bei offenem Foramen ovale

Platypnea-orthodeoxia is a rare syndrome that is often associated with interatrial shunting through a patent foramen ovale (PFO) or atrial septal defect. We describe the case of a 69-year-old woman with progressive dyspnea and hypoxia when standing, which was relieved by assuming the recumbent position. After detection of a PFO by transesophageal echocardiography the diagnosis was confirmed by transthoracic echocardiography using saline contrast injection while lying supine and standing upright. This maneuver demonstrated a large right-to-left shunt through a patent foramen ovale while the patient was in a upright position and no significant shunt while being in a recumbent position. The patient showed a rapid improvement after closure of the PFO. This case demonstrates that platypnea-orthodeoxia caused by a patent foramen ovale can be easily demonstrated by the technique of contrast transthoracic echocardiography and a simple positioning maneuver.

[Coagulation disorders in tumors and hemoblastoses]

Thromboembolic and haemorrhagic complications are not rarely seen in the course of malignant diseases. The underlying coagulation disorders were investigated by means of coagulation analysis in 61 patients with solid tumors and 60 control persons as well as 51 patients with leukemia and 50 control persons. As a cause for the thrombotic diathesis in patients with solid tumors and leukemias can be demonstrated a hypercoagulability (shortened PTT and raised factor VIII activity). In addition we found a raised level of fibrinogen, a hypofibrinolysis (prolonged euglobulin lysis time) and in increased platelet aggregation in patients with solid tumors. Predominantly bleeding complications in leukemias are caused by thrombopenia. Another reason, however, may be an activated fibrinolysis or a clot instability because of the reduction of factor XIII. Pathogenetic mechanisms, underlying the tumor induced coagulation disorders, as for example the release of tumor cell thromboplastins from malignant cells are discussed.