Chemistry of the Au-Thiol Interface through the Lens of Single-Molecule Flicker Noise Measurements.

Chemistry of the Au-S interface at the nanoscale is one of the most complex systems to study, as the nature and strength of the Au-S bond change under different experimental conditions. In this study, using mechanically controlled break junction technique, we probed the conductance and analyzed Flicker noise for several aliphatic and aromatic thiol derivatives and thioethers. We demonstrate that Flicker noise can be used to unambiguously differentiate between stronger chemisorption (Au-SR) and weaker physisorption (Au-SRR') type interactions. The Flicker noise measurements indicate that the gold rearrangement in chemisorbed Au-SR junctions resembles that of the Au rearrangement in pure Au-Au metal contact breaking, which is independent of the molecular backbone structure and the resulting conductance. In contrast, thioethers showed the formation of a weaker physisorbed Au-SRR' type bond, and the Flicker noise measurement indicates the changes in the Au-anchoring group interface but not the Au-Au rearrangement like that in the Au-SR case. Additionally, by employing single-molecular conductance and Flicker noise analysis, we have probed the interfacial electric field-catalyzed ring-opening reaction of cyclic thioether under mild environmental conditions, which otherwise requires harsh chemical conditions for cleavage of the C-S bond. All of our conductance measurements are complemented by NEGF transport calculations. This study illustrates that the single-molecule conductance, together with the Flicker noise measurements can be used to tune and monitor chemical reactions at the single-molecule level.

Juvenile Xanthogranuloma.

A solitary skin lesion of juvenile xanthogranuloma appearing at the age of five years is reported.

Keratosis Punctata of Palmar Creases.

Five cases of keratosis punctata of palmar creases which isaa variant of keratosis punctata are reported. Two of these cases were associated with psoriasis and one case with dermatitis herpetiformis. Familial tendency was noticed in 4 cases.& k4.00H.

Yolk sac and allied tumours of the ovary.

A review is presented of the histological appearances of 38 yolk sac tumours of the ovary and four so-called embryonal carcinomas together with the associated clinical features. It is suggested that these neoplasms belong to a single taxonomic group of embryonal ovarian tumours differing only in the concomitant types of differentiation. One yolk sac tumour occurred in an individual of 46 XY chromosome constitution and another in a patient with a gonadoblastoma in the contralateral ovary. The value of post-operative serial assays of serum AFP is stressed.

Müllerian adenosarcoma of the uterine body: a report of nine cases.

Nine cases of Mullerian adenosarcoma of the uterine body, first defined in 1974 by Clement & Scully, are described. The tumour usually occurs in elderly women and appears macroscopically as a polypoid mass filling the uterine cavity. Histologically these neoplasms are characterized by having a benign epithelial component set in a sarcomatous stroma. The epithelial element consists of tubular glands, cystically dilated glands and a surface epithelium. The glandular and surface epithelium usually resembles that of proliferative endometrium but may be of mucinous type and can undergo squamous metaplasia. Occasional mitotic figures, multilayering and intraluminal tufting are seen in the actively growing but benign glands which are considered to be an integral component of the tumour. The sarcomatous stroma contains spindle cells, round cells and, less frequently, multinucleated giant cells and rhabdomyoblasts. The Mullerian adenosarcoma represents a relatively benign variant of the mixed mesenchymal sarcoma of the uterus and is probably more common than is generally realized. Myometrial invasion is rarely deep and the majority of patients with this neoplasm survive. Vaginal recurrence occurs only in a minority of patients and distant metastasis is exceptional.

Morphological changes in the placenta and decidua after induction of abortion by extra-amniotic prostaglandin.

Seventeen placentae from second trimester abortions induced by the injection of extra-amniotic prostaglandin have been examined. The extraplacental membranes, the chorionic plate of the placenta, the placental intervillous space and the placental villi were normal in all cases. In all but one specimen lesions were, however, noted in the decidua, these including focal decidual necrosis, intradecidual haemorrhage, thrombosis of maternal vessels and dilatation and congestion of the maternal vasculature. Similar decidual lesions were also seen in placentae from spontaneous and surgical second trimester abortions and it is concluded that prostaglandins do not produce any specific lesions in the placenta or decidua. It is suggested that the negative findings of this study indicate that prostaglandins do not induce abortion by either direct injury to the placenta or by provoking utero-placental ischaemia.