Browsing by Author "Fox, J. A."
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- Maize dwarf mosaic virus: purification, some physical properties, and yield of virus from several corn hybridsJones, Ronald K. (Virginia Tech, 1971-04-05)To better understand the nature of maize dwarf mosaic virus (MDMV) and its interaction with susceptible and resistant corn hybrids, the purification of MDMV and its physical properties were re-evaluated and a rapid assay procedure was developed. The virus was purified by chloroform clarification and differential and sucrose density-gradient centrifugation. Corn tissue was homogenized in 0.1 M sodium citrate plus 0.5% mercaptoethanol. The virus was resuspended after high speed centrifugation in 0.005 M sodium citrate, pH 7.0. Purified virus has an ultraviolet absorption spectrum typical for filamentous viruses having 5% RNA, shows birefringence, has an A260/280 of 1.18, and a sedimentation coefficient of 160-162 S. The virus is filamentous and appears to be a member of the potato virus Y group. A yield of 9.0-23.0 llg of virus/g fresh weigh.t of field-grown, mechanically inoculated Hy X Cl03 was determined by analytical sucrose density-gradient centrifugation. This represents a yield of purified virus of approximately 25% of that in the clarified sap. Results obtained from the density-gradient analysis were comparable to but more sensitive than those from the microprecipitin test and a systemic infectivity assay. The systemic infectivity assay on corn, analyzed by maximum likelihood and log log transformation, showed a yield of purified virus of 0.4% of that in the crude sap.
- A morphological and systematic study of the first and second instars of the Kermesidae in the Nearctic region (Homoptera: Coccoidea)Baer, Ronald G. (Virginia Tech, 1978-08-01)The Cocco idea or scale insects are among the most important pests of sylvicultural, ornamental, agricultural and greenhouse plantings throughout the world. There are 21 families comprising 6,000 species. Direct injury occurs from the withdrawal of sap while feeding and from the production of galls. Some scale insects are host specific while others are polyphagous. They feed on many different parts of plants including the roots, trunk, stems, leaves, buds and fruit.
- Primary Acromioclavicular-Coracoclavicular Reconstruction Using 2 Allografts, TightRope, and Stabilization to the AcromionHaber, D. B.; Golijanin, P.; Stone, G. L.; Sanchez, A.; Murphy, C. P.; Peebles, L. A.; Ziegler, C. G.; Godin, J. A.; Fox, J. A.; Provencher, M. T. (Elsevier B.V., 2019-01-21)Acromioclavicular (AC) joint injuries are a common cause of shoulder pain, particularly among young athletes participating in contact sports. Injuries to the AC joint most commonly occur from direct impact at the acromion and are classified as types I to VI. Although most AC joint injuries can be treated nonoperatively, types IV to VI are best treated with surgery, with type III being controversial and most surgeons recommending an initial trial of nonoperative treatment. Although numerous surgical techniques have been described, no gold standard technique has been established. Biomechanical testing suggests that anatomic reconstruction of both the AC and coracoclavicular ligaments results in a superior surgical construct. The objective of this Technical Note is to describe our preferred technique for the primary treatment of AC joint instability in the acute and chronic setting. Using 2 free tendon grafts in combination with a cortical button suspensory device combines the advantages of a nonrigid biologic and anatomic AC and coracoclavicular ligament reconstruction while benefiting from the strength of a cortical suspensory device in resisting displacement of the AC joint. © 2018 Arthroscopy Association of North America