Identification and elimination of the causative agent of byssinosis

Separation and identification of possible causative agents of byssinosis have been high priority research activities at the Southern Regional Research Center since 1975. The Center serves as a focal point for several cooperating agencies also active in the search for this elusive agent. Several examples of recent research on proximate, elemental and microscopical analyses, as well as bioassays of cotton textile dust, washed cotton and dust obtained from selected cottonseed oil mills illustrate the multidisciplinary attack required by this area of research.     

Implementing IPsec — making security work on VPNs,intranets and extranets: Elizabeth Kaufman and Andrew Newman

For anyone who doesn’t know, the IPsec protocols were “designed to clear the hit list of well-known security flaws in the current Internet Protocol version 4 (Ipv4) and to provide a pre-emptive strike against these same flaws in its possible replacement, the Internet protocol version 6 (Ipv6)”. So, is IPsec the answer to all our network security problems, the simple cure all, or is this too good to be true? The authors of this particular book are of the opinion that IPsec “has raised by far the most hope…as a possible cure for the widespread security problems of networks and networked applications”. But, while offering hope to those responsible for increasingly more complex networks, the authors also prudently point out that “IPsec products can wreak havoc on critical applications and other enhanced networked services.” The problem is, while IPsec can indeed provide solutions never offered before (or in a manner never offered before) interoperability problems, limitations in the base protocols and failure to address known operational conflicts could court disaster. And here is the rub: the potential havoc wreaked could leave the most ambitious of doom laden hackers crazy with envy.     

Observations on the vertebro-basilar system studied by ultrasound

Vertebro-basilar circulation is complex because conditioned by several factors. Ultrasounds allow the study of many of its aspect, both hemodynamic and anatomical. Data were obtained from the examination of 50,000 patients over 25 years, of which the last 1,000 patients were examined by means of transcranial Doppler, duplex scanner color and power. 40% of these patients were found normal, 20% only had arterial thickening, 26% various types of stenosis, 10.6% subclavian steal, 14% short vertigo. The basilar artery (BA) flow (230 ml/min +/- 40) is similar to that of the internal carotid (245 ml/min +/- 50). In elderly patients, the absence of a posterior communicating artery (28%) or of both arteries (13%) is more frequent than the absence of the anterior communicating artery (7%). In normal patients decubitus variations do not modify the BA flow. In patients with vertigo due to decubitus variations, BA flow velocity increases from 20% to 40% during vertigo. Subclavian steal completely modifies the hemodynamics of vertebral arteries, while in the BA it can vary in part or completely. In conclusion, vertebral hemodynamics is different from BA hemodynamics. BA must be considered as one side of the Willis' polygon because it is an anastomosis between the vertebral arteries and is a "hemodynamic damper" between intracranial and extracranial circulation.     

Apheresis Platelet Rich-Plasma for Regenerative Medicine: An In Vitro Study on Osteogenic Potential

Background: Platelet-Rich Plasma (PRP) induces bone regeneration; however, there is low evidence supporting its efficacy in bone healing. The lack of a standardized protocol of administration represents the main obstacle to its use in the clinical routine for bone defects’ treatment. The purpose of this study was to characterize PRP and elucidate its osteogenic potential. Methods: Platelet count, fibrinogen levels, and growth factors concentration were measured in PRP obtained by four apheresis procedures. HOB-01-C1, a pre-osteocytic cell line, was used to examine the effects of different PRP dilutions (from 1% to 50%) on cell viability, growth, and differentiation. Gene expression of RUNX2, PHEX, COL1A1, and OCN was also assayed. Results: PRP showed a mean 4.6-fold increase of platelets amount compared to whole blood. Among the 36 proteins evaluated, we found the highest concentrations for PDGF isoforms, EGF, TGF-β and VEGF-D. PDGF-AA positively correlated with platelet counts. In three of the four tested units, 25% PRP induced a growth rate comparable to the positive control (10% FBS); whereas, for all the tested units, 10% PRP treatment sustained differentiation. Conclusions: This study showed that PRP from apheresis stimulates proliferation and differentiation of pre-osteocyte cells through the release of growth factors from platelets.     

Stray light analysis for the Thomson scattering diagnostic of the ETE Tokamak

Thomson scattering is a well-established diagnostic for measuring local electron temperature and density in fusion plasma, but this technique is particularly difficult to implement due to stray light that can easily mask the scattered signal from plasma. To mitigate this problem in the multipoint Thomson scattering system implemented at the ETE (Experimento Tokamak Esfe?rico) a detailed stray light analysis was performed. The diagnostic system was simulated in ZEMAX software and scattering profiles of the mechanical parts were measured in the laboratory in order to have near realistic results. From simulation, it was possible to identify the main points that contribute to the stray signals and changes in the dump were implemented reducing the stray light signals up to 60 times.