Cellular senescence predicts treatment outcome in metastasised colorectal cancer

Background: Cellular senescence is a terminal cell-cycle arrest that occurs in response to activated oncogenes and DNA-damaging chemotherapy. Whether cancer cell senescence at diagnosis might be predictive for treatment outcome is unknown. Methods: A senescence index (SI) was developed and used to retrospectively correlate the treatment outcome of 30 UICC stage IV colorectal cancer (CRC) patients with their SI at diagnosis. Results: 5-Fluorouracil/leucovorin-treated CRC patients achieved a significantly longer progression-free survival when presenting with SI-positive tumours before therapy (median 12.0 vs 6.0 months; P=0.044). Conclusion: Cancer cell senescence predicts treatment outcome in metastasised CRC. Prospective analyses of larger patient cohorts are needed

Laserschweißen von Mischverbindungen: Einsatz brillanter Strahlquellen und hochfrequenter Strahloszillatoren

Getrieben von der allgemeinen Forderung, Bauteile möglichst effizient eigenschafts- und gewichtsoptimiert herzustellen, sind stoffschlüssig gefügte Mischverbindungen in vielen Anwendungsbereichen gefordert. Das Schweißen von Kombinationen aus verschiedenen Werkstoffen ermöglicht, die spezifischen Eigenschaften der Stoffe optimal zu nutzen. Dies gestaltet sich jedoch in vielen Fällen schwierig, da die Komponenten sich deutlich in ihren thermophysikalischen und stofflichen Eigenschaften unterscheiden

Carotenoid Radical Cations as a Probe for the Molecular Mechanism of Nonphotochemical Quenching in Oxygenic Photosynthesis.

Nonphotochemical quenching (NPQ) is a fundamental mechanism in photosynthesis which protects plants against excess excitation energy and is of crucial importance for their survival and fitness. Recently, carotenoid radical cation (Car•+) formation has been discovered to be a key step for the feedback deexcitation quenching mechanism (qE), a component of NPQ, of which the molecular mechanism and location is still unknown. We have generated and characterized carotenoid radical cations by means of resonant two color, two photon ionization (R2C2PI) spectroscopy. The Car•+ bands have maxima located at 830 nm (violaxanthin), 880 nm (lutein), 900 nm (zeaxanthin), and 920 nm (β-carotene). The positions of these maxima depend strongly on solution conditions, the number of conjugated C=C bonds, and molecular structure. Furthermore, R2C2PI measurements on the light-harvesting complex of photosystem II (LHC II) samples with or without zeaxanthin (Zea) reveal the violaxanthin (Vio) radical cation (Vio•+) band at 909 nm and the Zea•+ band at 983 nm. The replacement of Vio by Zea in the light-harvesting complex II (LHC II) has no influence on the Chl excitation lifetime, and by exciting the Chls lowest excited state, no additional rise and decay corresponding to the Car•+ signal observed previously during qE was detected in the spectral range investigated (800−1050 nm). On the basis of our findings, the mechanism of qE involving the simple replacement of Vio with Zea in LHC II needs to be reconsidered

Microstructure and Residual Stress Formation in Induction-Assisted Laser Welding of the Steel S690QL

Steels of high mechanical strength combined with high toughness, such as those in quenched and tempered condition are required to reduce weight in industrial machinery. Their mechanical performance is impaired by welding operations which often cause a reduction of toughness and increase the probability for cold cracking due to martensite formation in the weld seam. The limited weldability of high-strength steels therefore demands appropriate joining procedures to increase their use in industrial construction and reduce reworking costs. Induction heating is capable of directly producing heat inside a work piece. This enables the integration of induction heat-treatments into serial welding processes. In this work, the effect of induction-assisted laser welding on the microstructure and residual stresses in S690QL butt joints was investigated. The results reveal that conventional laser welding causes strong martensite formation in the weld seam and the heat-affected zone. This leads to prohibitive hardness values. Induction heat-treatments result in an efficient reduction of hardness in the fusion zone. However, the efficiency decreases with increasing sheet thicknesses. The residual stress distributions after laser welding with and without induction heating are typical of fusion welding. Although an effective reduction of hardness is achieved by induction-assisted laser welding, the residual stresses remain significantly high