Nonequilibrium polariton dynamics in organic microcavities

Journal ArticleMicrocavities containing a J-aggregate forming organic dye were prepared in the strong-coupling regime. Changing the position of the neat organic films within the microcavity allows a tuning of the giant Rabi splitting observed. We set the Rabi splitting to 25 meV and study the thermal activation of the higher-energy polariton emission under excitation off resonance. This is found to exhibit an Arrhenius activation with an energy corresponding to the polariton branch splitting. A constant offset to the upper polariton is observed at low temperature. Microsecond gated spectroscopy reveals that thermalization of the system occurs on the time scale of milliseconds, which contrasts with the polariton lifetime in the range of picoseconds. Bulk sample heating cannot fully account for the slow polariton thermalization observed in steady-state experiments, suggesting that long-lived macroscopic polariton coherence influences the polariton relaxation

Novel solvates M(BH4)3S(CH3)2 and properties of halide-free M(BH4)3 (M = Y or Gd)

Rare earth metal borohydrides have been proposed as materials for solid-state hydrogen storage because of their reasonably low temperature of decomposition. New synthesis methods, which provide halide-free yttrium and gadolinium borohydride, are presented using dimethyl sulfide and new solvates as intermediates. The solvates M(BH4)3S(CH3)2 (M = Y or Gd) are transformed to a-Y(BH4)3 or Gd(BH4)3 at ~140 °C as verified by thermal analysis. The monoclinic structure of Y(BH4)3S(CH3)2, space group P21/c, a = 5.52621(8), b = 22.3255(3), c = 8.0626(1) Å and ß = 100.408(1)°, is solved from synchrotron radiation powder X-ray diffraction data and consists of buckled layers of slightly distorted octahedrons of yttrium atoms coordinated to five borohydride groups and one dimethyl sulfide group. Significant hydrogen loss is observed from Y(BH4)3 below 300 °C and rehydrogenation at 300 °C and p(H2) = 1550 bar does not result in the reformation of Y(BH4)3, but instead yields YH3. Moreover, composites systems Y(BH4)3–LiBH4 1 : 1 and Y(BH4)3–LiCl 1 : 1 prepared from as-synthesised Y(BH4)3 are shown to melt at 190 and 220 °C, respectively

Pressure-induced structural transitions triggering dimensional crossover in lithium purple bronze Li0.9M6O17

At ambient pressure, lithium molybdenum purple bronze (Li0.9Mo6O17) is a quasi-one dimensional solid in which the anisotropic crystal structure and the linear dispersion of the underlying bands produced by electronic correlations possibly bring about a rare experimental realization of Tomomaga-Luttinger liquid physics. It is also the sole member of the broader purple molybdenum bronzes family where a Peierls instability has not been identified at low temperatures. The present study reports a pressure-induced series of phase transitions between 0 and 12 GPa. These transitions are strongly reflected in infrared spectroscopy, Raman spectroscopy, and x-ray diffraction. The most dramatic effect seen in optical conductivity is the metallization of the c-axis, concomitant to the decrease of conductivity along the b-axis. This indicates that high pressure drives the material away from its quasi-one dimensional behavior at ambient pressure. While the first pressure-induced structure of the series is resolved, the identification of the underlying mechanisms driving the dimensional change in the physics remains a challenge.Comment: 10 pages, 12 figure

Multicentre phase II study of gemcitabine and cisplatin in malignant pleural mesothelioma

Malignant pleural mesothelioma is a notoriously chemoresistant tumour. However, a recent single institution study showed an impressive activity of gemcitabine and cisplatin. Our aim is to investigate the efficacy and toxicity of a gemcitabine and cisplatin combination in selected and chemo-naive patients with histologically proven malignant pleural mesothelioma. Method: Gemcitabine 1250 mg m−2 was administered on day 1 and day 8 and cisplatin 80 mg m−2 was administered on day 1 in a 3-week cycle with a maximum of six cycles. Response and toxicity evaluations were performed according to WHO and NCIC-CTC criteria. Pathology and radiology were centrally reviewed. Results show that in 25 evaluable patients, four PR were observed (ORR 16%, 95% CI 1–31%). Responses of seven patients were unevaluable. No unexpected toxicity occurred. Time to progression was 6 months (5–7 months) with a median survival from registration of 9.6 months (95% CI 8–12 months). In conclusion this trial excludes with 90% power a response rate of greater than 30% in patients with malignant pleural mesothelioma using a combination of gemcitabine and cisplatin at the proposed dose and schedule

Multifunctionality of silver closo-boranes

Silver compounds share a rich history in technical applications including photography, catalysis, photocatalysis, cloud seeding and as antimicrobial agents. Here we present a class of silver compounds (Ag2B10H10 and Ag2B12H12) that are semiconductors with a bandgap at 2.3?eV in the green visible light spectrum. The silver boranes have extremely high ion conductivity and dynamic-anion facilitated Ag(+) migration is suggested based on the structural model. The ion conductivity is enhanced more than two orders of magnitude at room temperature (up to 3.2?mS?cm(-1)) by substitution with AgI to form new compounds. Furthermore, the closo-boranes show extremely fast silver nano-filament growth when excited by electrons during transmission electron microscope investigations. Ag nano-filaments can also be reabsorbed back into Ag2B12H12. These interesting properties demonstrate the multifunctionality of silver closo-boranes and open up avenues in a wide range of fields including photocatalysis, solid state ionics and nano-wire production

Angiogenesis is an independent prognostic factor in malignant mesothelioma

Angiogenesis is essential for tumour growth beyond 1 to 2 mm in diameter. The clinical relevance of angiogenesis, as assessed by microvessel density (MVD), is unclear in malignant mesothelioma (MM). Immunohistochemistry was performed on 104 archival, paraffin-embedded, surgically resected MM samples with an anti-CD34 monoclonal antibody, using the Streptavidin–biotin complex immunoperoxidase technique. 93 cases were suitable for microvessel quantification. MVD was obtained from 3 intratumoural hotspots, using a Chalkley eyepiece graticule at × 250 power. MVD was correlated with survival by Kaplan–Meier and log-rank analysis. A stepwise, multivariate Cox model was used to compare MVD with known prognostic factors and the EORTC and CALGB prognostic scoring systems. Overall median survival from the date of diagnosis was 5.0 months. Increasing MVD was a poor prognostic factor in univariate analysis (P = 0.02). Independent indicators of poor prognosis in multivariate analysis were non-epithelial cell type (P = 0.002), performance status > 0 (P = 0.003) and increasing MVD (P = 0.01). In multivariate Cox analysis, MVD contributed independently to the EORTC (P = 0.006), but not to the CALGB (P = 0.1), prognostic groups. Angiogenesis, as assessed by MVD, is a poor prognostic factor in MM, independent of other clinicopathological variables and the EORTC prognostic scoring system. Further work is required to assess the prognostic importance of angiogenic regulatory factors in this disease. http://www.bjcancer.com © 2001 Cancer Research Campaign  http://www.bjcancer.co

STM-induced light emission from thin films of perylene derivatives on the HOPG and Au substrates

We have investigated the emission properties of N,N'-diheptyl-3,4,9,10-perylenetetracarboxylic diimide thin films by the tunneling-electron-induced light emission technique. A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules. The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes. The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained

Prognostication and monitoring of mesothelioma using biomarkers:a systematic review

Background: Radiological markers of treatment response and prognostication in malignant pleural mesothelioma have limitations due to the morphology of the disease. Serum or pleural fluid biomarkers that could act as an adjunct to radiological assessment would be of significant value. The aim of this review was to collate and summarise the literature relating to this topic. Methods: A systematic review was performed on the databases Pubmed and EMBASE to identify relevant studies. Two independent researchers read the abstracts and used the Quality in Prognostic Studies tool to assess the quality of the evidence. Results: Forty-five studies were identified from the current literature. Twenty studies investigated the role of serum soluble mesothelin with majority suggesting that it has variable utility as a baseline test but when measured serially correlates with treatment response and prognosis. Several studies demonstrated that serum osteopontin correlated with survival at baseline. Other biomarkers have shown prognostic utility in individual studies but are yet to be reproduced in large cohort studies. Conclusions: From the available literature no serum or pleural fluid biomarker was identified that could be recommended currently for routine clinical practice. However, a falling serum soluble mesothelin might correlate with treatment response and improved survival