The aim of this research was to verify, in vitro, the effect of various porcelain surface treatment on the shear strength of orthodontic brackets bonded to porcelain and the mode of fracture after debonding. Eighty-eight samples of metallic supported feldspathic porcelain were randomly divided into four groups according to their surface preparation as follows: the porcelain was maintained intac...

Gunter Zveig, Doctor of Philosophy, 1952. (B, S, University of Maryland, 194-A) Title of Thesis: An In-Vitro Study of Transmethylation. Thesis directed by Dr. Fletcher P. Veitch.

The isolation of carbohydrate variants from cultures of HeLa and conjunctival cells was described. Factors inherent in the cell culture system, such as parent populations and dialyzed serums, have been shown to influence the outcome of variant isolations. Established stable variants incorporated significantly more pentoses or lactate into various cell fractions than the parent cultures. Besides...

A clonal rat fetal liver cell line that expresses the functions of differentiated liver cells under controllable conditions has been established. Normal fetal liver cells were transformed by a temperature-sensitive A (tsA) mutant (tsA209) of simian virus 40. At the permissive temperature (33 degrees C), the tsA209-transformed liver cell line (RLA209-15) can be cultured indefinitely and cloned r...

Teichomycin A2 was evaluated in vitro against clinical isolates, and its activity was compared with that of other antibiotics. This compound was very active against all organisms tested; its activity was comparable to that of vancomycin, and it was superior to several other antibiotics when tested against gram-positive cocci. Because of its in vitro activity, it deserves clinical evaluation.

Aims and objectives: The aim of this in vitro study was to evaluate self-adhering composite Dyad flow (Kerr, USA) as a pit and fissure sealant. The objectives were to assess the degree of microleakage with self-adhering composite Dyad flow and that with Fissurit F as pit and fissure sealants and, to compare the same between these two materials. Materials and Methods: 20 premolars extracted for ...

BACKGROUND Orthodontic tooth movement results from application of forces to teeth. Elastics in orthodontics have been used both intra-orally and extra- orally to a great effect. Their use, combined with good patient co-operation provides the clinician with the ability to correct both anteroposterior and vertical discrepancies. Force decay over a period of time is a major problem in the clinical...

Three new cephalosporins, ceftazidime, ceftizoxime, and cefotiam, were evaluated in vitro against clinical isolates, and their activities were compared with those of other cephalosporins, mezlocillin, and tobramycin. All three new cephalosporins were very active against gram-positive cocci (except enterococci), but mezlocillin was more active against Streptococcus ssp. Cefotiam and cefamandole ...

Cerebral autoregulation can be duplicated in vitro using the large middle cerebral arteries from a calf. The limits of autoregulation were between 50 and 150 mm Hg. Excessively high pressures may lead to the appearance of the "sausage- or bead-string" response followed by forced dilation. These results suggest the existence of an intrinsic myogenic mechanism responsive to intraluminal pressure ...