A next generation, pilot-scale continuous sterilization system for fermentation media

A new continuous sterilization system was designed, constructed, started up, and qualified for media sterilization for secondary metabolite cultivations, bioconversions, and enzyme production. An existing Honeywell Total Distributed Control 3000-based control system was extended using redundant High performance Process Manager controllers for 98 I/O (input/output) points. This new equipment was retrofitted into an industrial research fermentation pilot plant, designed and constructed in the early 1980s. Design strategies of this new continuous sterilizer system and the expanded control system are described and compared with the literature (including dairy and bio-waste inactivation applications) and the weaknesses of the prior installation for expected effectiveness. In addition, the reasoning behind selection of some of these improved features has been incorporated. Examples of enhancements adopted include sanitary heat exchanger (HEX) design, incorporation of a “flash” cooling HEX, on-line calculation of F(o) and R(o), and use of field I/O modules located near the vessel to permit low-cost addition of new instrumentation. Sterilizer performance also was characterized over the expected range of operating conditions. Differences between design and observed temperature, pressure, and other profiles were quantified and investigated

FOREIGN-BODY REACTIONS TO RESORBABLE POLY(L-LACTIDE) BONE PLATES AND SCREWS USED FOR THE FIXATION OF UNSTABLE ZYGOMATIC FRACTURES

In a previous article in the Journal of Oral and Maxillofacial Surgery, the initial results of treating 10 patients with solitary, unstable, displaced zygomatic fractures using resorbable poly(l-lactide) (PLLA) plates and screws was reported (Bos et al, 1987). This article describes the long-term results in these patients. Three years postoperatively, four patients returned because they were concerned about an intermittent swelling at the site of implantation. The remaining patients were recalled after the same postoperative period. All patients were examined clinically, and six patients were operated on again for evaluation of the swelling and to investigate the nature of the tissue reaction. The explanted material showed remnants of degraded PLLA surrounded by a dense fibrous capsule. The swelling was classified as a nonspecific foreign body reaction to the degraded PLLA material. Ultrastructural investigation of the degraded material showed an internalization of crystal-like PLLA material in the cytoplasm of various cells.<br/

A three-dimensional study of loads across the fracture for different fracture sites of the mandible

The loads across the fracture depend on variables such as position of the fracture and the bite point. Up to now, no study has described systematically the influence of these two variables on these loads. The aim of this study was to describe and compare value and direction of the loads across the fracture for different positions of fractures in the mandible. In a three-dimensional model, bending and torsion moments and shear forces were compared for five mandibular fractures. The fractures were located in, respectively, the angle, posterior body, anterior body, canine and symphysis region. Positive bending moments were defined to give compression at the border, negative bending moments to give compression at the alveolar side of the mandible. The angle and posterior body fracture have high positive bending moments, small torsion moments and high sheer forces. The anterior body, canine and symphysis fracture have high negative bending moments and high torsion moments with similar maximum values. The number of bite points with negative bending moments were different for all fractures. These bite points were always located on the fractured side. It is concluded that mandibular fractures can be divided roughly into two groups with similar load patterns across the fracture. One group consists of angle and posterior body fractures, the other group consists of anterior body, canine and symphysis fractures

Poly(L-lactide) implants for repair of human orbital floor defects:Clinical and magnetic resonance imaging evaluation of long-term results

Purpose: The purpose of this study was to evaluate the long-term outcome of repair of orbital floor defects in patients with resorbable as-polymerized poly(L-lactide) (PLLA) implants and to determine whether these patients showed symptoms that could be indicative of the presence of a late tissue response. Patients and Methods: Six patients (four women, two men; mean age, 39 years; range, 18 to 67 years) treated with PLLA implants for orbital floor fractures were recalled for follow-up examination after a period ranging from 31/2 to 61/2 years. The examination consisted of an interview and a physical examination, including an ophthalmologic and orthoptic consultation, For evaluation of the orbital tissues, coronal spin echo T1- and T2-weighted magnetic resonance images (MRls) were made through both orbits. Results: None of the patients reported any problems in the years preceding the follow-up examination that might have indicated complications, Clinical examination of the operative sites revealed no abnormalities. At ophthalmologic and orthoptic consultation, normal eye function, without diplopia or restriction of motility, was found in all patients. The MRls showed no indication of an abnormal or increased soft tissue reaction in the orbital region. Conclusions: Based on the results of this study, it can be concluded that PLLA orbital floor implants have the potential for successful use in repair of human orbital floor defects