Processing highly filled pre‐compounded pellets on single screw extruders

This article discusses, in general terms, several approaches to producing highly filled plastics. Emphasis is on wood flour, with polyolefins as an example. Processing other highly filled polymer and filler choices follows the same logic. Successful approaches include the single screw machine being fed pre‐pelletized material. A large pelletizing twin screw compounder selected for compounding for its output rate isolates the complexities of the compounding step from the profile lines, which have their own unique challenges, such as sizing and cooling the part at good quality and with good tolerances. Operating a few big pelletizing twin screw machines would allow the simple single screw lines of various sizes to run at decent efficiencies on big or small profiles. Since not one machinery approach has monopolized this application to date, some of the major processing and equipment comparisons are discussed. J. VINYL. ADDIT. TECHNOL. 12:83–86, 2006. © 2006 Society of Plastics Engineers     

A pilot study of a short cognitive-behavioral group treatment for female recurrent suicide attempters

The SLT2(MPK1) mitogen-activated protein kinase signal transduction pa thway has been implicated in several biological processes in Saccharomyces cerevisiae, including the regulation of cytoskeletal and cell wall structure, polarized cell growth, and response to nutrient availability, hypo-osmotic shock and heat shock. We examined the conditions under which the SLT2 pathway is activated. We found that the SLT2 kinase is tyrosine phosphorylated and activated during periods in which yeast cells are undergoing polarized cell growth, namely during bud formation of vegetative cell division and during projection formation upon treatment with mating pheromone. BCK1(SLK1), a MEK kinase, is required for SLT2 activation in both of these situations. Upstream of BCK1(SLK1), we found that the STE20 kinase was required for SLT2 activation by mating pheromone, but was unnecessary for its activation during the vegetative cell cycle. Finally, SLT2 activation during vegetative growth was partially dependent on CDC28 in that the stimulation of SLT2 tyrosine phosphorylation was significantly reduced directly after a temperature shift in cdc28 ts mutants. Our data are consistent with a role for SLT2 in promoting polarized cell growth.     

Redox gene therapy protects human IB-3 lung epithelial cells against ionizing radiation-induced apoptosis

Toxicity to nontumor-derived tissue has proven to be a significant obstacle in achieving therapeutic levels of gamma irradiation in the treatment of cancer. The formation of reactive oxygen species (ROS) such as superoxide radicals (O2-) following irradiation is thought to be a major determinant of cellular damage. To this end, we describe the generation of two recombinant adenoviral vectors expressing the radical-scavenging enzymes MnSOD and CuZnSOD to test therapeutic strategies of radioprotection. Using a human lung epithelial cell line (IB-3), we have demonstrated that infections with both Ad.CMVMnSOD or Ad.CMVCuZnSOD significantly increase both the levels of SOD protein and enzymatic activity as compared to control cells. This increase in SOD expression reduced the level of apoptosis at 72 hr post-irradiation by 50% as compared to mock- or Ad.CMVLacZ-infected cells. Such studies provide the foundation for radioprotective gene therapies in the treatment of cancer.     

Potassium hexacyanocobalt ferrate and ammonium molybdophosphate sorption bags for the removal of 137Cs from aqueous solutions and a simulated waste

In the present study, the removal and immobilization of ¹³⁷Cs from aqueous waste solutions and a simulated waste was investigated. Two inorganic ion‐exchange complexes: di‐potassium hexacyanocobalt(II)‐ferrate(II), K₂CoFe(CN)_6·xH₂O (KCFC), and ammonium‐12‐molybdophosphate [(NH₄)₃PMo₁₂O_40·aq] (AMP), were charged separately into porous nylon bags (sorption bags) of 5 µm pore diameter. The first complex (KCFC) was prepared in our laboratory. The second (AMP) was used for comparison. Easy handling and increased potential for reuse characterize the sorption bag technique. The KCFC complex was investigated by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA), porosity, infra‐red (IR) and X‐ray powder diffraction (XRD). The chemical and structural investigations revealed that the KCFC complex has adequate ion‐exchange capacity and high affinity for ¹³⁷Cs. The sorption bag technique showed promising results for the removal of ¹³⁷Cs from aqueous waste solutions. The KCFC bags showed the highest ¹³⁷Cs removal (～0.91 g g^?1), at pH 8.5; AMP bags gave the highest ¹³⁷Cs removal (～0.97 g g^?1) in 0.1 N HNO₃ and 1.5 N HNO₃, both with a waste: sorbent ratio of 80 cm³ g^?1. Sorption data for both KCFC and AMP revealed a good fit to the Freundlich sorption isotherm. To assess the potential of sorption bags, the used bags were regenerated in different leachants and reused in further sorption investigations. ¹³⁷Cs recovery from the used sorbents was ～0.46 g g^?1 using 6 N HCl as leachant for AMP, compared with ～0.253 g g^?1 for KCFC using 6 N NaCl. These results indicated stronger cesium immobilization in the KCFC complex. Copyright © 2003 Society of Chemical Industry     

Early gastric cancer and Helicobacter pylori: 34 years of experience at Charity Hospital in New Orleans

Good survival rates have been reported for resected early gastric adenocarcinoma (EGC) in patients found via screening procedures. However, the prevalence of Helicobacter pylori in EGC in unscreened populations is unclear. The major purpose of this investigation was to analyze the clinical experience and incidence of H. pylori in unscreened patients presenting with EGC at Charity Hospital over a 34-year period. From 1963 through 1997, the tumor registry at Charity Hospital compiled data on 2497 patients evaluated for gastric carcinoma. Of these patients, 26 (1%) had lesions that were confined to the mucosa or submucosa, i.e., T1N0M0 (American Joint Commission on Cancer classification). Pathology specimens and medical records were retrieved for confirmation of diagnosis and retrospective analysis for H. pylori. H. pylori was analyzed by Steiner staining and immunohistochemistry using a polyclonal antibody. EGC was detected in 12 men and 14 women with a mean age of 62 years. Upper gastrointestinal X-ray studies were performed on 19 of the 26 patients and failed to conclusively demonstrate a lesion in any case. Endoscopy was performed on 22 patients, and preoperative biopsies were positive in 95 per cent of these. Operative procedures included 2 local excisions and 22 subtotal and 2 total gastrectomies. No extended nodal dissections were performed. Microscopic evaluation revealed lesions limited to the mucosa in 63 per cent of cases and involving the submucosa in 37 per cent of the cases. Of the 14 patients evaluable of H. pylori, 79 per cent were positive for the bacterium. The status of 2 patients is unknown, and only 1 patient died of the original gastric cancer, for a disease-free survival of 96 per cent. The 5-year and 10-year overall survival rates were calculated to be 50 per cent and 21 per cent, respectively, when all causes of death were taken into consideration. Median follow-up of the survivors was 64 months. Resection of early gastric carcinoma in unscreened patients without extended lymphadenectomy yielded excellent results. H. pylori was present in 79 per cent of cases. These data suggest an association between H. pylori and EGC. Whether H. pylori infection is an etiologic factor in gastric cancer remains an area of active research.     

The HMG-CoA reductase inhibitor atorvastatin increases the fractional clearance rate of postprandial triglyceride-rich lipoproteins in miniature pigs

We have previously shown in vivo that the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin decreases hepatic apolipoprotein B (apoB) secretion into plasma. To test the hypothesis that atorvastatin modulates exogenous triglyceride-rich lipoprotein (TRL) metabolism in vivo, an oral fat load (2 g fat/kg body wt) containing retinol (50 000 IU) was given to 6 control miniature pigs and to 6 animals after 28 days of treatment with atorvastatin 3 mg. kg-1. d-1. A multicompartmental model was developed by use of SAAM II and kinetic analysis performed on the plasma retinyl palmitate (RP) data. Peak TRL (d<1.006 g/mL; Sf>20) triglyceride concentrations were decreased 29% by atorvastatin, and the time to achieve this peak was delayed (5.2 versus 2.3 hours; P<0.01). The TRL triglyceride 0- to 12-hour area under the curve was decreased by 24%. In contrast, atorvastatin treatment had no effect on peak TRL RP concentrations, time to peak, or its rate of appearance into plasma; however, the TRL RP 0- to 12-hour area under the curve was decreased by 20%. Analysis of the RP kinetic parameters revealed that the TRL fractional clearance rate was increased significantly, 1.4-fold (3.093 versus 2.276 pools/h; P=0.012), with atorvastatin treatment. The percent conversion of TRL RP from the rapid-turnover to the slow-turnover compartment was decreased by 47% with atorvastatin treatment. The TRL RP fractional clearance rate was negatively correlated with very low density lipoprotein apoB production rate measured in the fasting state (r=-0.49). Thus, although atorvastatin had no effect on intestinal TRL assembly and secretion, plasma TRL clearance was significantly increased, an effect that may relate to a decreased competition for removal processes by hepatic very low density lipoprotein.