Observation of a non-Hermitian phase transition in an optical quantum gas.

Quantum gases of light, such as photon or polariton condensates in optical microcavities, are collective quantum systems enabling a tailoring of dissipation from, for example, cavity loss. This characteristic makes them a tool to study dissipative phases, an emerging subject in quantum many-body physics. We experimentally demonstrate a non-Hermitian phase transition of a photon Bose-Einstein condensate to a dissipative phase characterized by a biexponential decay of the condensate's second-order coherence.

Prognostic significance of the proliferative activity in neuroblastoma.

The prognostic significance of the immunohistochemically assessed growth fraction in neuroblastomas was determined in relation to tumor grade and tumor stage. A total of 101 cases of neuroblastoma were examined with the monoclonal antibodies PC10 against proliferating cell nuclear antigen (PCNA) and Ki-S5 against the Ki-67 protein. Patients were followed for a mean time of 4.

Diagnostic assessment of two novel proliferation-specific antigens in benign and malignant melanocytic lesions.

The aim of this study was to gain a thorough insight into the proliferative activity of benign and malignant melanocytic tumors. A total of 314 cases were examined by immunohistochemistry on paraffin-embedded material. The growth fraction was assessed by means of two monoclonal antibodies, Ki-S1 and Ki-S5, which react with two different proliferation-specific nuclear antigens.

Expression of CD30 and nerve growth factor-receptor in neoplastic and reactive vascular lesions: an immunohistochemical study.

A total of 118 biopsies from 20 different types of benign, malignant and reactive vascular proliferations were examined for the expression of the CD30 antigen using the monoclonal antibodies BerH2 and HRS4 on paraffin-embedded sections. The results were compared with those obtained using an antibody directed against the partially homologous nerve growth factor-receptor. The vascular character of the lesions was assessed by means of endothelial markers and the expression of intermediate filaments was verified immunohistochemically.

[Determination of proliferation activity of prostate cancers by means of nuclear proliferation-associated formalin resistant Ki-S5 antigens].

In order to evaluate the growth fraction in normal, hyperplastic and neoplastic prostatic tissue, we examined paraffin sections of 55 cases of prostatic cancer containing areas of benign (BPH) and atypical hyperplasia (AH). Cellular proliferation was assessed by nuclear staining with the monoclonal antibody Ki-S5 directed against a formalin-resistant epitope of the Ki67 antigen. The proliferation rate was minimal in normal glands and BPH (mean 0.