Gold Chain Formation via Local Lifting of Surface Reconstruction by Hot Electron Injection on H2(D2)/Au(111).

The hexagonal close packed surface of gold shows a 22 × 3 "herringbone" surface reconstruction which makes it unique among the (111) surfaces of all metals. This long-range energetically favored dislocation pattern appears in response to the strong tensile stress that would be present on the unreconstructed surface. Adsorption of molecular and atomic species can be used to tune this surface stress and lift the herringbone reconstruction. Here we show that herringbone reconstruction can be controllably lifted in ultrahigh vacuum at cryogenic temperatures by precise hot electron injection in the presence of hydrogen molecules. We use the sharp tip of a scanning tunneling microscope (STM) for charge carrier injection and characterization of the resulting chain nanostructures. By comparing STM images, rotational spectromicroscopy and ab initio calculations, we show that formation of gold atomic chains is associated with release of gold atoms from the surface, lifting of the reconstruction, dissociation of H2 molecules, and formation of surface hydrides. Gold hydrides grow in a zipper-like mechanism forming chains along the [11̅0] directions of the Au(111) surface and can be manipulated by further electron injection. Finally, we demonstrate that Au(111) terraces can be transformed with nearly perfect terrace selectivity over distances of hundreds of nanometers.

Exciton dynamics of C60-based single-photon emitters explored by Hanbury Brown-Twiss scanning tunnelling microscopy.

Exciton creation and annihilation by charges are crucial processes for technologies relying on charge-exciton-photon conversion. Improvement of organic light sources or dye-sensitized solar cells requires methods to address exciton dynamics at the molecular scale. Near-field techniques have been instrumental for this purpose; however, characterizing exciton recombination with molecular resolution remained a challenge. Here, we study exciton dynamics by using scanning tunnelling microscopy to inject current with sub-molecular precision and Hanbury Brown-Twiss interferometry to measure photon correlations in the far-field electroluminescence. Controlled injection allows us to generate excitons in solid C60 and let them interact with charges during their lifetime. We demonstrate electrically driven single-photon emission from localized structural defects and determine exciton lifetimes in the picosecond range. Monitoring lifetime shortening and luminescence saturation for increasing carrier injection rates provides access to charge-exciton annihilation dynamics. Our approach introduces a unique way to study single quasi-particle dynamics on the ultimate molecular scale.

[Clinical usefulness of immunocytochemical and genetic-molecular investigations in diagnosis of neoplasms of organs of sight]. / Przydatnosc kliniczna badan immunocytochemicznych i genetyczno-molekularnych w rozpoznawaniu nowotworów narzadu wzroku.

AIM: To determine the usefulness of immunocytochemical (icch) and genetic-molecular (g-m) investigations in diagnosing neoplasm cases of eye, eye socket and eyeball, and to determine how far these investigations precise the diagnosis made using other methods. MATERIALS AND METHODOLOGY: 38 patients with neoplasm cases of eye, eye socket and eyeball were examined, performing routine ophthalmological examinations and auxiliary examinations such as USG, TK, roentgenography. Material for the cytological examination, icch and g-m, was obtained by way of fine needle biopsy (bac) in 18 patients with tumor of eye socket, conjunctiva or eyelid and in 1 patient with intraocular tumour. In the remaining patients with intraocular tumours print smears after eyeball removal were made. RESULTS: 100% conformability of cytological diagnoses, supplemented with icch evaluation, with the final diagnosis was found. The g-m examination made in 2 cases of lymphoma confirmed the clonal nature of the hyperplasia. CONCLUSIONS: Icch examinations make possible the diagnosis in cytological smear of histological type of mature and low-differentiated neoplasms. In tumours of eye and eye socket cases the diagnosis thus made allows to take a decision on conservative or operative therapy. In intraocular examinations these examinations find applications in diagnostically especially difficult cases.

[Neoplasm metastasis to the eye--diagnosis and therapy]. / Przerzuty nowotworowe do galki ocznej--rozpoznawanie i leczenie.

PURPOSE: The increasing occurrence of neoplastic metastases to the eye encouraged us to present our own observation on this topic. MATERIAL AND METHODS: We have examined 17 patients with metastatic tumors of the eye (in 6 cases there was bilateral involvement). The group included 11 females and 6 males, aged 43 to 69 years. The most common primary tumor was breast carcinoma (9 women-13 eyes); then cancers of lung (4 men), gastrointestinal tract (2 women-3 eyes), maxillary sinus (1 case); and malignant lymphoma (1 case). In 5 patients the eye was enucleated because of secondary glaucoma. RESULTS: Improvement or stopping the progression of the disease was achieved in 1 of 2 patients treated with argon laser, 3 of 6 patients treated with xenon lamp photocoagulation, and in all 8 eyes treated with gamma-therapy. In one case of metastatic tumor of the iris a partial iridectomy was performed. A case of systemic malignant lymphoma was treated pharmacologically. CONCLUSIONS: It seems that the best option of treatment of eye metastases is gamma-therapy, particularly effective in small lesions. Authors emphasize that it is necessary to perform routine ophthalmologic examinations in patients with breast cancer, lung cancer, and other neoplasms associated with high risk of metastases to the eye. This can allow to early detect eye metastases and start the appropriate treatment.

The cytological, immunocytochemical and molecular genetic analysis in diagnosis of the neoplasms of the eye, eye adnexa and orbit.

The fine needle aspiration biopsy was performed in 91 patients including 57 cases of retrobulbar tumors done under CT control. All aspirates were cytologically examined. In 21 cases immunocytochemical examination was performed in order to distinguish poorly differentiated neoplasms. In 19 cases malignant lymphoma was distinguished from pseudolymphoma. Cytological diagnosis was confirmed by histopathological examination in 77 cases /84%/. One result was false positive, 3-false negative. The value of immunocytochemical methods in differential diagnosis of poorly differentiated neoplasms was stressed.

[Neoplasms of the orbit and ocular adnexa in children--diagnosis and treatment]. / Nowotwory oczodolu i aparatu ochronnego oka u dzieci--rozpoznawanie i leczenie.

Analysis of diagnosis and treatment of the orbit and ocular adnexa in 38 children was made. In 24 cases (63%) benign and in 14 (37%) malignant neoplasms were diagnosed. Among malignant neoplasms there were: 1 melanoma of the conjunctiva, 5 lymphoma, 1 carcinoma sebaceum, 1 pigmentary progonoma, 3 rhabdomyosarcoma, 1 fibrosarcoma and 2 embryonic ganglioma. Usefulness of the applied diagnostic methods and results of treatment are discussed. Long-term results were good in all benign lesions. In malignant neoplasms, they depend on the period of diagnosis and beginning of the therapy.

[RFLP-PCR technique for exclusion of carrier status of the mutated Rb gene]. / Technika RFLP-PCR w wykluczeniu nosicielstwa zmutowanego genu Rb.

Molecular-genetic analysis of DNA by PCR-RFLP technique in a family with a case of unilateral retinoblastoma was performed. The carrier status of mutated Rb gene in a sister of proband was excluded on the basis of molecular analysis despite unsynonymous pedigree data.