Cooperativity Studies

It has been demonstrated that chemical structure directly affects cooperativity. To simplify the research, one amorphous polymer with a high molecular weight was chosen. Polymethyl methacrylate (PMMA) was purchased from Aldrich in the powder form. Gel permeation chromatography showed a Mw of 101,300 g/mol with a polydispersity of 1.967. 

Polished silicon wafers one inch in diameter and -0.30 mm thick were purchased from Wafer World, Inc. The wafers were held isothermally at 90°C for 90 minutes in a 30/70 solution by volume of H2O2 and H2SO4 respectively. Next, they were submersed in acetone in a sonicator for 30 minutes. The wafers were then rinsed with acetone and dried in a stream of air. This treatment produced a native oxide layer on the silicon wafers that were used as the substrate for depositing thin films of PMMA. 

Solutions of PMMA in toluene were prepared at 2%, 5%, and 10% by weight. The silicon wafers were positioned on the spin coater and several drops of solution were placed on the wafer. Immediately, each sample began rotating at a constant speed to 

Samples of PMMA were heated in a vacuum oven at 120°C for 24 hours to drive off any moisture that had been absorbed. One sample of approximately 15 mg was placed in aluminum pans in a TA Instruments DSC 2920. The sample was equilibrated at 25°C and then heated from 25°C to 180°C at 10°C/min for the first run. The sample was then cooled slowly, again equilibrated at 25°C and the heating process was repeated for a second run. All of these tests used nitrogen as a purge gas. The glass transition function in TA Instrumental Analysis was used to calculate the Tg of the material by finding the inflection point in the Tg step. 

160 mg/mL solution of PMMA in chloroform was prepared. One sample of 100 oL was injected into a Waters 150CALC GPC with an internal viscometer, Viscotek Model T60A, and an external refractive index instrument. The flow rate of the run was 1.000 mL/min. 

---

Le Breton, M.D. (1984), Hot and cold fuel volatility Indexes of french cars. A cooperative study by the GFC volatility group . SAE paper No. 84-1386, International fuels and lubricants meeting, Baltimore, MD. 

Veterans Administration Cooperative Study Group,/ Am. Med. Assoc. 202, 116 (1967). 

Veterans Administration Cooperative Study Group on Antihypertensive Agents,/. A.m. Med. Mssoc. 248, 2004 (1982). 

U.S. Pubhc Health Service Cooperative Study Group, Circ. Res. (SuppL I) 40, 1098 (1977). 

Determinarion of MW and MWD by SEC using commercial narrow molecular weight distribution polystyrene as calibration standards is an ASTM-D5296 standard method for polystyrene (11). However, no data on precision are included in the 1997 edition of the ASTM method. In the ASTM-D3536 method for gel-permeation chromatography from seven replicates, the M of a polystyrene is 263,000 30,000 (11.4%) for a single determination within the 95% confidence level (12). A relative standard deviation of 3.9% was reported for a cooperative determination of of polystyrene by SEC (7). In another cooperative study, a 11.3% relative standard deviation in M, of polystyrene by GPC was reported (13). 

Sano M, Ernesto C, Thomas RG et al (1997) A controlled trial of selegiline, alpha-tocopherol, or both as treatment for Alzheimer s disease. The Alzheimer s Disease Cooperative Study. N Engl JMed 336 1216-1222... 

The opinions expressed in this chapter are solely those of the author and do not necessarily reflect those of the Department of Veterans Affairs (DVA), the VA Cooperative Studies Program (VACSP), or the Hines VA Cooperative Studies Program... 

Mazen Abdellatif, Hines VA Cooperative Studies Program Coordinating Center (151K), P.O. Box 5000, 5th Ave. and Roosevelt Rd. Bldg. 1, Rm. B240, Hines, IL 60141-5000, USA. (mazen.abdellatif med.va.gov). 

As an example consider the data presented in Tables 35.1-35.4. These tables are extracted from a much larger data base obtained in an international cooperative study on the sensory aspects of olive oils [1]. Table 35.1 gives the mean scores for 16 samples of olive oil with respect to six appearance attributes given by a Dutch sensory panel. Table 35.2 gives similar scores for the same samples as judged by a... 

Flanigan RC, Reda DJ, Wasson JHM, et al. 5 year outcome of surgical resection and watchful waiting for men with moderately symptomatic benign prostatic hyperplasia a Department of Veterans Affairs cooperative study. J Urol 1998 160 12-17. 

The Veteran Affairs Total Parenteral Nutrition Cooperative Study Group. Perioperative total parenteral nutrition in surgical patients. N Eng J Med 1991 325 525-532. 

Rollins C, Thomson C, Crane T. Pharmacotherapeutic issues. In Rolandelli RH, Bankhead R, Boullata JI, Compher CW, eds. Enteral and Tube Feeding. 4th ed. Philadelphia Elsevier 2005 291-305. van den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in the critically ill patients. New Engl J Med 2001 345 1359-1367. Veterans Affairs Total Parenteral Nutrition Cooperative Study Group. Perioperative total parenteral nutrition in surgical patients. New Engl J Med 1991 325 525-532. 

Bartlett JG, Condon RE, Gorbach SL, Clarke JS, Nichols RL, Ochi S Veterans Administration Cooperative Study on Bowel Preparation for Elective Colorectal Operations Impact of oral antibiotic regimen on colonic flora, wound irrigation cultures and bacteriology of septic complications. Ann Surg 1978,188 249-254. 

The Italian Cooperative Study Group on Chronic Myeloid Leukemia., Interferon alpha-2a as compared with conventional chemotherapy for the treatment of chronic myeloid leukemia, N. Engl. J. Med., 330, 820, 1994. 

The International Chronic Granulomatous Disease Cooperative Study Group., A controlled trial of interferon gamma to prevent infection in chronic granulomatous disease., N. Engl. J. Med, 324, 509, 1991. 

Netter, P. et al., Adverse effects of D-penicillamine. A cooperative study by the French regional drug surveillance centers, J. Rheumatol., 15, 1730, 1988. 

Galer et al., 1993 Sina et al., 1995). As a result of this cooperative study, several of the participating companies have implemented the routine use of several of these alternative models in their test batteries (R. G. Sussman and J. Sina, personal communications), thus effectively increasing the number and classes of compounds evaluated in alternative models. 

Veterans Administration of Cooperative Study Group on Antihypertensive Agents Effects of treatment on morbidity in hypertension. II. Results in patients with diastolic blood pressure averaging 90 through 114 mm Hg., J.A.M.A., (1970), 213, 1143. 

In the 1970s, the Sagami Chemical Research Center in Japan provided nutrient reference material for the Cooperative Study of the Kuroshio Current (the so-called CSK standards). These solutions were not prepared in seawater, which limits their general utility (see below), however they are still distributed and widely used as a common reference. French and British scientists have conducted some studies on nutrient reference material (Aminot and Keroul, 1991, 1996 Zhang et al., 1999) with limited success. 

Schrijvers D, Johnson J, Jiminez U, et al. Phase III trial of modulation of cisplatin/fluorouracil chemotherapy by interferon alfa-2b in patients with recurrent or metastatic head and neck cancer. Head and Neck Interferon Cooperative Study Group. J Clin Oncol 1998 16 1054-1059. 

The treatment of CAD for the alleviation of angina was evaluated in several trials that ultimately shaped the role of coronary angioplasty. Prior to this, trials such as the Veterans Administration Cooperative Study (VA Study) [13, 14] and the Coronary Artery Surgery Study (CASS) trial [15] established the role of revascularization for the improvement in survival and symptom relief A meta-analysis (Table 5.1) regarding surgical revascularization (CABG) versus... 

Murphy ML, Hultgren HN, Detre K, et al. Treatment of chronis stable angina a preliminary report of survival data of the randomized Veterans Administration Cooperative Study. N Engl J Med 1977 297 621. 

Treiman DM, Meyers PD, Walton NY, Collins IF, Colling C, Rowan AJ et al. A comparison of four treatments for generalized convulsive status epilepticus. Veterans Affairs Status Epilepticus Cooperative Study Group. N Engl J Med 1998 339(12) 792-8. 

D) The VA cooperative study was a landmark trial demonstrating the beneficial effect of hydralazine and nitrate combination in patients of heart failure. 

---