Probing the local structure and mechanical response of nanostructures using force modulation and nanofabrication.

Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy.

Evaluation of the safety of sodium pectate as a food ingredient.

New potential uses of pectates in food products have recently stimulated interest in re-evaluating the information available concerning the safety of pectins and pectates as food ingredients. Data relevant to this re-evaluation have been obtained in rats in recent 14-day and 13 wk subchronic feeding studies with sodium pectate. Ames tests and other mutagenicity tests have been conducted with sodium pectate, bleached sodium pectate and mixed sodium/calcium pectate salts. These toxicological studies with pectates have provided further evidence of their safety, and support of the continued GRAS status of pectins and pectate salts.

Histopathological classification of 272 primary epithelial tumors of the lacrimal gland.

272 primary epithelial gland tumors were classified pathologically. These tumors were sampled from 70% of 390 lacrimal fossa lesions out of 1530 orbital tumors from one hospital. Benign mixed tumors ranked the first in frequency (52%) to be followed by adenocystic carcinomas (25%) and malignant mixed tumors (9%). From the other less common tumor types, we identified, for the first time 3 polymorphous low-grade adenocarcinomas, 2 spindle celled myoepitheliomas and one carcinosarcoma of the lacrimal gland. The diagnosis and differential diagnosis of polymorphous low-grade adenocarcinoma and spindle cell myoepithelioma were discussed.

Single-beam interferometry of a thermal bump.

A novel single-beam interferometric measurement of a thermal bump produced by an intensity modulated and focused laser beam is described. The effects of the ac change in optical reflectivity and the displacement of the surface are determined independently by fitting data to a phenomenological theory. This technique is insensitive to sample vibrations and variations in optical path resulting from thermal fluctuations.

Intraocular paragonimiasis.

A case of intraocular paragonimiasis is reported in a 13-year-old Chinese boy. The disease manifested as repeated attacks of acute intraocular pain associated with panuveitis. A combination of inflammatory reaction and ocular findings mimicking both perforating and contusion injuries caused by the migration of the fluke within the eye characterises the infection. The living fluke was successfully extracted from the anterior chamber and identified as Paragonimus westermani.

Sympathetic ophthalmia: a comparison of the histopathological features from a Chinese and American series.

The importance of this comparison between two large series of cases of sympathetic ophthalmia lies in its confirmation of our previous findings, which differ somewhat from the classical pathological description. Sympathetic ophthalmia remains a clinicopathological diagnosis, relying on a history of perforating injury to one eye, followed after a variable incubation period by inflammation in the fellow eye. The inflammatory changes in both eyes consist of a diffuse, granulomatous proliferation throughout the uveal tract, which involves the choriocapillaris and the retina late in its course. The infiltrate is composed predominantly of lymphocytes and plasma cells, with a variable number of epitheloid and giant cells. Corticosteroid therapy may modify this picture. The epithelioid cells contain phagocytosed pigment granules, but there is not sign of necrosis. Eosinophils appear early in the course of the disease and disappear late. The granulomatous inflammation may spread to involve the optic nerve sheath, the nerve itself, the scleral emissaria, and the scleral stroma. Dalén-Fuchs nodules appear early peripherally, and it is over these nodules that retinal granulomas, when present, usually are found. In the Shanghai series, it was found that corticosteroid therapy and prompt enucleation of the exciting eye reduced the number of exacerbations experienced by these patients but did not improve visual prognosis. The MEEI data, while they did show a bimodal distribution to the visual result, seemed to indicate that prompt enucleation of a blind eye combined with aggressive corticosteroid therapy may improve visual prognosis.

Uveal melanoma in China.

We reviewed 65 cases of uveal melanoma from the Shanghai Eye, Ear, Nose, and Throat Hospital between 1956 and 1979. These 65 cases occurred at a rate of 4.5 cases per 10,000 inpatients on the ophthalmology service. Uveal melanoma is more frequently encountered in China than previous reports have suggested. In China, as in the United States, uveal melanoma is the most frequently occurring primary intraocular neoplasm in adults. We observed a strikingly younger age distribution of our cases; almost 20 percent of cases in our series involved patients between the ages of 19 and 30. The largest number of cases was seen in the fifth decade. However, only 5 cases (8 percent) were seen in the sixth decade. Fundus lesions, which were observed to stimulate choroidal melanoma, are similar to those encountered in the United States. One contrast was the importance of inflammatory lesions in the differential diagnosis of choroidal melanoma. Management of cases was surgical in all instances. A lower percentage of spindle cell tumors and a higher percentage of epitheloid tumors were seen than in most Western series.