Immunogenicity of a Salmonella typhi CVD 908 candidate vaccine strain expressing the major surface protein gp63 of Leishmania mexicana mexicana

Attenuated Salmonella typhi are attractive for use as live vector vaccines to express protozoal antigens and deliver them to the human immune system. The gene encoding the mature form of Leishmania mexicana mexicana gp63 under control of tac promoter was integrated into the delta aroC locus of the chromosome of attenuated delta aroC, delta aroD S. typhi strain CVD 908. After oral immunization of BALB/c mice with two 1 x 10(9) colony forming unit doses given 21 days apart, CVD 908 omega (delta aroC::Ptac-gp63) elicited a broad T cell-mediated immune response against L. m. mexicana gp63 as demonstrated by: (1) lymphoproliferative response to fixed whole L. m. mexicana promastigotes; (2) activation of IL-2 (but not IL-4)-producing lymphocytes; (3) appearance of cytotoxic T cells against mouse mastocytoma cells expressing gp63. This T-cell mediated immune response was associated with significant protection in F1 (BALB/cXC57Bl/6) mice challenged in their footpads with a wild type strain of L. m. mexicana.     

Use of the suture anchor in open Bankart reconstruction. A follow-up report

We previously reported early results of a new technique using a suture anchor to perform a modified Bankart reconstruction. That study included patients from two medical centers and had an average followup of only 1 year. This report includes patients from a single center with followup extended to a mean of 42 months (range, 33 to 61). Between April 1988 and August 1991, 53 patients with recurrent anterior glenohumeral instability underwent modified Bankart reconstruction with the use of a suture anchor. Thirty-two patients met inclusion criteria (identifiable Bankart lesion, open repair with suture anchors, and minimum followup of 2 years); 4 patients were lost to followup. There have been no complications as a result of this technique. Ninety-three percent of the patients in the study had objectively excellent or good results. There were 2 failures with recurrent anterior dislocation. The use of a suture anchor can simplify the Bankart reconstruction. At average followup of 3 years, 26 patients have returned to presurgery activity levels without recurrent dislocation or subluxation. However, careful attention to anchor placement at the junction of articular cartilage and the glenoid neck is necessary to avoid technical failure.     

Nonlinear optical susceptibility of HgGa2S4

The second harmonic coefficient d36of HgGa2S4has been measured to be 5 times larger than d36(LiNbO3). The birefringence is usefully large.     

A two-stage learning control system

Learning heuristics for an on-line controller are presented, and various aspects of the problem are discussed. The controller is required to achieve optimal regulator control for an unknown process in the face of random disturbances. A computer method of two-stage learning is employed in which the first stage is coarse and attempts to satisfy the terminal boundary conditions on the basis of subgoal learning. This yields an approximation to the optimum control law. Rote learning is also carried out during this time. The second, or tuning stage, improves on this result by a technique of reinforcement learning applied to the integral performance criterion. The effect of varying the parameters associated with the learning algorithm is studied. A discussion of a hybrid computer simulation of a second-order plant subject to one input with two possible levels is presented.     

Altered electrodermal responsivity associated with clinical pain

We used certain physiologic maneuvers to perturb the autonomic nervous system (ANS) in an attempt to detect a link between the ANS and pain. In the unperturbed state, we found no difference in the electrodermal response among normal controls, preoperative patients (increased stress without pain) and postoperative patients (increased stress and pain). The electrodermal response elicited by autonomic maneuvers was significantly attenuated in postoperative patients but not in preoperative patients or in normal control subjects.     

Energy Transfer in Molecular Collisions

Computational studies of energy transfer in models of molecular collisions are presented and analyzed qualitatively and semi-quantitatively. Particular attention is given to those approximations where the leading term is already in good qualitative agreement with the exact numerical results. In particular, results for the distorted wave approximation in an adiabatic basis are reported and compared with the exact results. It is argued that for slow molecular collisions, the efficiency of the transfer is determined by the “Franck Condon” overlap near the repulsive part of the intermolecular potential.     

The aging behavior of orthorhombic marten site in Ti-6-2-4-6

In Ti-6-2-4-6 alloys, beta transforms to orthorhombic martensite when quenched from a temperature of 1188 or above, X-ray analysis showed that aging at 773 or 873 gradually reduces the degree of orthorhombicity until a hexagonal structure equivalent to alpha, but having the morphological characteristics of the prior martensite, is produced. The orthorhombicity is reduced by solute rejection to beta which forms as particles both homogeneously and heterogeneously within the martensitic structure. The structure at maximum hardness is a fine distribution of Burger’s oriented beta particles in a matrix of martensite of greatly reduced orthorhombicity. Overaging appears to occur as a result of coarsening of the homogeneous beta particles. It is shown that aging at temperatures from 873 to 1083 K results in growth of one particular varient of the beta which is located at the interface between twin related regions composing a martensite lath. This beta along with similarly oriented beta at lath interfaces forms a continuous beta matrix by a gradual growth process. It is shown that this matrix has the identical orientation and shape of the original beta grain prior to quenching. A mechanism is proposed to account for this “memory effect”.