Influence of the process parameters of an intermeshing co‐rotating twin screw extruder on the morphology and notched Izod impact strength of PBT/ABS/MGE blends

In this research, it was studied the effects of the processing parameters applied to a twin screw extruder on the morphology and impact strength of poly(butylene terephthalate)/acrylonitrile‐butadiene‐styrene blends with and without a reactive compatibilizer. It was found that the increase of the feed rate highly decreased the ductile brittle transition temperature (DBTT) and slightly increased the room temperature impact strength (RTIS) of the compatibilized blends. Besides the influence of the feed rate, it was also found that the compatibilized blends could reach high RTIS and low DBTT values by an appropriate combination of the compatibilizer feeding position in the extruder, the screw rotation speed and the width of the kneading discs of the screw. The DBTT was found to be at least partially controlled by the spatial distribution of the rubbery particles, which was quantified by finite body tessellation, a method applied for the first time in polymer blends. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Modeling the effect of an outbreak of bovine herpesvirus type 1 on herd-level milk production of Dutch dairy farms.

One of the impacts of disease is its effect on milk production. In the present study the effect of an outbreak of bovine herpesvirus type 1 on milk production at the herd level of certified bovine herpesvirus type 1-free dairy farms was modeled. The objective was to study several linear models to quantify the effects of a bovine herpesvirus type 1 outbreak on milk production accounting for the repeated measurements and incorporating our assumptions about the most likely duration of effects of this virus. Because milk production is measured at regular intervals, the data consisted of repeated measurements at the herd and cow levels. A marginal model, a subject-specific random-effect model, and a transition model were developed. The effect of a bovine herpesvirus type 1 outbreak was statistically significant in the random-effect model, and this model fitted the investigated farms best. However, a transition model might be a better model for generalizing the results to the whole population of Dutch dairy farms. The effect of a bovine herpesvirus type 1 outbreak on milk production derived from the random-effect model amounted to, on average, a loss of 0.92 kg of milk per cow per day during a period of 9 wk. The milk production loss varied from almost none to 2 kg of milk per cow per day. This reduction resulted in an average loss of Dfl 372 (Dfl1 = $US $0.50) with lower and upper confidence limits of, respectively, Dfl 12 and Dfl 730 per bovine herpesvirus type 1 outbreak.     

Can duplex scan arterial mapping replace contrast arteriography as the test of choice before infrainguinal revascularization?

PURPOSE: Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography. METHODS: Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon. RESULTS: Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM. CONCLUSION: DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites.     

Reexamining the delivery system as part of Medicare reform

Medicare is more than a payment system. As the nation's largest public payer of health care, Medicare dictates the way health care is delivered to elderly and disabled persons. Health care and health outcomes cannot make substantial improvements until the delivery system is changed. Medicare reform must support a coordinated health care delivery system (in place of hospital-centered, fragmented care) and proactive chronic disease management (in place of episodic, reactive care). Consumers, government, community-based agencies, employers, health plans, and others need to develop a shared understanding of what outcomes we want to obtain, what delivery system reforms are required, and how financing can support those reforms.     

Double mutant cycle analysis of aspartate 69, 97, and 103 to asparagine mutants in the m2 muscarinic acetylcholine receptor

Double mutant cycles provide a method for analyzing the effects of a mutation at a defined position in the protein structure on the properties of an amino acid at a second site. This approach was used to map potential interactions between aspartates 69, 97, and 103 in the m2 muscarinic acetylcholine receptor transmembrane helices 2 and 3. Receptors containing single and double aspartate to asparagine mutants were expressed in Chinese hamster ovary cells and their effects on ligand binding, signal transduction, and thermal stability determined. Analysis of the double mutant cycles showed that the mutations had approximately additive effects on ligand binding, signal transduction, and thermal stability. Ligand binding and thermal inactivation results support the conclusion that aspartate-103 is the ligand amine counterion. Effector coupling properties of the mutant receptors showed that aspartate-103 was also required for signal transduction activity. The mutation of aspartate-69 to asparagine completely eliminated signal transduction by the agonists acetylcholine, carbachol, and pilocarpine but not oxotremorine M, which caused reduced but significant inhibition of adenylyl cyclase and stimulation of phospholipase C. In contrast, adenylyl cyclase stimulation by the asparagine-69 mutant was elicited only by acetylcholine and carbachol but not by oxotremorine M. The variation in agonist-dependent effector coupling properties provides evidence that the asparagine-69 mutant can exist in activated receptor states that are different from the wild-type m2 muscarinic receptor.     

Multiple autoimmune events after autologous bone marrow transplantation

A 36-year-old woman with RAEB-t and severe bone marrow fibrosis undergoing autologous BMT, developed a histologically documented GVHD-like skin rash. Thereafter, autoimmune thyroiditis, autoimmune thrombocytopenic purpura and autoimmune hemolytic anemia and a lupus anti-coagulant (LAC) were diagnosed. The patient is still alive, symptom-free and in first complete remission (CR); however, all of the autoantibodies are still detectable, with the exception being the anti-erythrocyte antibody. The most outstanding feature of the present case is the polymorphism of the autoimmune events, in the absence of a coexisting systemic autoimmune disease. This patient has achieved long-term disease-free survival (DFS) in first CR despite high-risk MDS and the repeated immunosuppressant therapy required because of the complications described above; a GVL reaction somewhat similar to the autoimmune events may have contributed towards maintaining disease control.     

Sodium ramping in hemodialysis: a study of beneficial and adverse effects

Sodium ramping has been introduced as a technique to decrease side effects occurring during hemodialysis. We studied sodium ramping in 414 dialysis sessions in 23 patients by randomizing 2-week blocks of dialysis to either steady dialysate sodium of 140 mEq/L, linear sodium ramping during dialysis from 155 mEq/L to 140 mEq/ L, or stepwise ramping (sodium of 155 mEq/L for 3 hours and 140 mEq/L for 1 hour). We studied the number and severity of hypotensive and hypertensive episodes. A hypotensive episode was defined as an abrupt decline of systolic blood pressure of more than 50 mm Hg, a decrease in blood pressure accompanied by symptoms requiring intervention, or systolic blood pressure of less than 90 mm Hg even without symptoms. A hypertensive episode was defined as a sudden increase in systolic blood pressure of over 30 mm Hg. We also recorded other side effects (headache, cramps, nausea, vomiting, dizziness, thirst, fatigue, weight gain, and blood pressure) during, immediately after, and between dialysis sessions. There was no major difference between the two ramping protocols, but compared with standard dialysis, both decreased total number of side effects from 4.0 to 3.0 (P = 0.057); the number of hypotensive episodes decreased from 1.3 to 0.7 (P = 0.036). The lowest blood pressure was 114/66 mm Hg during control and 123/69 mm Hg during ramping (P < 0.0001). The frequency of cramps during dialysis decreased from 0.9 to 0.5 (P = 0.006). There was no difference in headache, nausea, or vomiting. The number of hypertensive episodes increased from 0.045 to 0.086 during ramping (P = 0.125). Of 23 patients, only five (22%) had a marked decrease in symptoms; two of the three most symptomatic patients showed no significant improvement. Between dialysis sessions, patients complained of more fatigue and thirst (P < 0.0001 and P = 0.0028, respectively), and interdialytic weight gain following ramping was 5.1% of body weight compared with 4.4% without ramping (P < 0.0001). Blood pressure also increased following ramping, from 143/79 mm Hg to 152/81 mm Hg (P = 0.001). Ramping can decrease the overall number of side effects, but increases interdialytic symptoms, weight gain, and hypertension. In most instances, it simply changes the time the side effects occur. Only 22% of patients have significant benefit. These patients can be identified only through trial and error, as no model of these patients can be created.     

Primary chemotherapy for stage 2 testis cancer

To evaluate the efficacy and toxicity of primary chemotherapy in patients with stage 2 (retroperitoneal lymph node metastases) testis cancer, 20 consecutive patients referred to Groote Schuur Hospital between September 1992 and March 1994 were reviewed. There were 10 patients with non-bulky non-seminomatous germ cell tumour (NSGCT), 5 with bulky NSGCT and 5 with bulky seminoma. The treatment regimen consisted initially of 4 cycles of cisplatin, etoposide and bleomycin. Patients with NSGCT and a residual mass after chemotherapy subsequently underwent retroperitoneal lymph node dissection (RPLND) and those with seminoma underwent a low dose of irradiation to the mass. In 7 (70%) of the 10 patients with non-bulky NSGCT, there was a complete response to chemotherapy and 3 patients underwent limited RPLND. One patient relapsed at follow-up but remains clear of disease after salvage therapy. The survival rate is 100% at a median follow-up of 60 months (range 12-143 months). In 5 patients with bulky NSGCT there was no complete response to chemotherapy. Three have undergone limited RPLND. The survival rate is 52% at a median follow-up of 130 months (range 108-152 months). In 5 patients with bulky seminomas, the survival rate is 100% at a median follow-up of 55 months (range 29-92 months). Toxicity has been modest except for 1 patient who died postoperatively in the early part of the study. Four patients have fathered children after treatment. We conclude that primary chemotherapy is the treatment of choice for patients with stage 2 testis cancer.