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Radioactive lanthanides have become an important imaging, diagnostic and therapeutic tool in the medical field. The objective of our research was to investigate the feasibility of producing radioactive lanthanides with high specific activity in a small-scale research reactor using the Szilard–Chalmers method. The results indicate that the activated nuclides recoil out of the target after neutron capture and we obtain enrichment of the radionuclide compared to the bulk irradiation. These first attempts, result in enrichment factors and yields that are low but indicates a possibility of using this technique if the method is further optimized.

A variety of processes, from material sterilization and cancer treatment to used nuclear fuel recycling, benefit from quantifying the sensitivity of the system to radiation. Determining the effects of alpha irradiation on a system may be of complementary interest to the effects of gamma irradiation, as alpha radiation has higher linear energy transfer (LET) and will likely result in different chemical damage effects. This becomes important in advanced nuclear fuel cycle processes where the radioactive materials to be handled in solutions contain significant amounts of alpha emitters. Here we describe a method for studying high LET radiation in a liquid system using a TRIGA® reactor and the 10B(n,α)7Li reaction. By fitting a model based on neutron diffusion and absorption to experimentally obtained Fricke dosimetry data, the high LET dose to a sample was predictable over the full range of reactor power available and varying 10B concentration. This method may be applied to study the effects of high LET radiation on any liquid system as long as a suitable molecule containing boron is used and appropriate neutron diffusion coefficients are known. A wide range of high LET dose rates from 1,000 kGy/h may be obtained with this method.

Reagents used in chemical separation processes for used nuclear fuel are susceptible to radiolysis. Here we investigate the 10 B(n,α) 7 Li reaction for inducing high linear energy transfer (LET) radiolysis. A solution of tributyl phosphate (TBP) in n-dodecane, representing the PUREX solvent, was irradiated by gamma rays from a 137 Cs source and by high LET particles from the 10 B(n,α) 7 Li reaction in the UC Irvine TRIGA reactor. TBP degradation and Dibutyl phosphate (DBP) formation were quantified by gas chromatography. Our data show a significantly larger formation of DBP in the presence of gamma radiation compared to high LET radiation.

Fluoroquinolones, as a class of broad-spectrum antibiotics, have been detected in both surface and ground waters, and advanced oxidation/reduction processes (AO/RPs) are currently in development to remove these and other pharmaceuticals from wastewater because currently utilized treatment methods have proven to be ineffective. This article reports the reaction kinetics of six common fluoroquinolones with hydroxyl radicals and hydrated electrons, which are the major reactive species involved in AO/RPs. The bimolecular reaction rate constants (M(-1) s(-1)) for orbifloxacin, flumequine, marbofloxacin, danofloxacin, enrofloxacin, and the model compound, 6-fluoro-4-oxo-1,4-dihydro-3-quinoline carboxylic acid, with *OH are (6.94 +/- 0.08) x 10(9), (8.26 +/- 0.28) x 10(9), (9.03 +/- 0.39) x 10(9), (6.15 +/- 0.11) x 10(9), (7.95 +/- 0.23) x 10(9), (7.65 +/- 0.20) x 10(9), and with e(aq)(-), (2.25 +/- 0.02) x 10(10), (1.83 +/- 0.01) x 10(10), (2.41 +/- 0.02) x 10(10), (1.68 +/- 0.02) x 10(10), (1.89 +/- 0.02) x 10(10), and (1.49 +/- 0.01) x 10(10). These rate constants are related to the functional groups attached to the quinolone core, particularly the steric hindrance of the piperazine ring, making it possible to obtain a preliminary estimate of the *OH rate constant of an arbitrary fluoroquinolone by observing the ring constituents. In addition, the products of gamma-irradiation degradation of fluoroquinolones were analyzed by LC-MS to elucidate the probable pathways of AO/RPs degradation. Results indicate that preliminary degradation pathways include hydroxyl radical attack on the aromatic ring with subsequent hydroxylation, the substitution of a fluorine atom with a hydroxyl group, and the removal of the piperazine-derived side chain.

The vibrations of phosphate (PO−34) ions in single crystals of hexagonal Ba5(PO4)3F (B-FAP) have been investigated by means of polarized Raman scattering and compared to Raman frequencies observed in fluoroapatite analogs Sr5(PO4)3F (S-FAP) and Ca5(PO4)3F (FAP). The Raman vibrational frequencies decrease upon substitution of Ba2+ for Sr2+ or Ca2+ in the lattice, asymtotically approaching the Raman frequencies for vibrations of the free ion. Splitting of the vibrational Raman frequencies is also observed. The observed splitting is in accord with predictions made by a group theory analysis of the factor group of the unit cell. The effects of the host lattice environment on the magnitude of the Davydov splittings and frequency shifts of crystals within the fluorapatite structure are demonstrated to be inversely proportional to the unit cell volume and proportional to the crystal field in the host crystal.

The design of a pair of 20 kA nitrogen vapor cooled current leads for service in a 0.4 T background field for the NHMFL Series-Connected Hybrid Magnet has been completed. The leads are comprised of a nitrogen vapor cooled resistive section made from pierced copper sheet and a high-temperature superconducting section made with stacked and soldered Sumitomo Type G Bi-2223 tape. A detailed discussion of the HTS section design, including findings from an in-house critical current characterization effort, magnetic field on the tapes, current and temperature margins and protection considerations is presented.

The quantitative Knowledge Space Theory is applied here for the first time to specific science concepts in order to evaluate its feasibility as a general assessment method for science learning. In particular, the knowledge states of students in the 4th through 12th grades are suggested for three science concepts before and after classroom teaching/learning experiences. The theory belongs to the vast category of latent trait models based upon the Rasch model, but differs in all its most important characteristics by having the power to extract the cognitive organization of the material. Student responses to the pre‐tests and the post‐tests were analyzed for the pressure concept, the density concept and the conservation of matter, and tentative critical learning pathways for each concept are suggested which describe the most probable sequences of learning steps. In all three cases the quantitative results show a change in the students’ logic structure after the classroom experience. Knowledge Space Theory sh...

Treatment of used nuclear fuel through solvent extraction separation processes is hindered by radiolytic damage from radioactive isotopes present in used fuel. The nature of the damage caused by the radiation may depend on the radiation type, whether it be low linear energy transfer (LET) such as gamma radiation or high LET such as alpha radiation. Used nuclear fuel contains beta/gamma emitting isotopes but also a significant amount of transuranics which are generally alpha emitters. Studying the respective effects on matter of both of these types of radiation will allow for accurate prediction and modeling of process performance losses with respect to dose. Current studies show that alpha radiation has milder effects than that of gamma. This is important to know because it will mean that solvent extraction solutions exposed to alpha radiation may last longer than expected and need less repair and replacement. These models are important for creating robust, predictable, and economical processes that have strong potential for mainstream adoption on the commercial level. The effects of gamma radiation on solvent extraction ligands have been more extensively studied than the effects of alpha radiation. This is due to the inherent difficulty in producing a sufficient and confluent dose of alpha particles within a sample without leaving the sample contaminated with long lived radioactive isotopes. Helium ion beam and radioactive isotope sources have been studied in the literature. We have developed a method for studying the effects of high LET radiation in situ via 10B activation and the high LET particles that result from the 10B(n,α)7Li reaction which follows. Our model for dose involves solving a partial differential equation representing absorption by 10B of an isentropic field of neutrons penetrating a sample. This method has been applied to organic solutions of TBP and CMPO, two ligands common in TRU solvent extraction treatment processes. Rates of degradation of TBP and CMPO and their respective degradation products in the presence of high LET radiation are presented and discussed. These results are also compared to gamma studies performed in our lab and other gamma and alpha studies found in the literature. The possible application of this method to a variety of other solvent extraction ligands to study the effects of high LET radiation is also considered.Copyright © 2013 by ASME

The oxygen isotopes16O and18O were determined using reactor instrumental neutron activation analysis by utilizing the16O(n, p)16N and the18O(n, γ)19O reaction in the UCI 250 kw TRIGA research reactor.1 Such measurements were used to follow an exchange reaction between H218O and finely ground coal. The best conditions for the determination were explored and interference reactions quantified. Single irradiation/count sequences were used to determine 30 parts per thounsand of16O and 1 part per thousand of18O in a 400 mg sample of an HVA rank coal to a 25% (1σ) precision. Reactor pulses were shown to improve these detection limits significantly. Special attention was given to correcting for the high count rates from other induced activites.

The calcium concentration in bone samples which contain 0 to 37% calcium is readily measured rapidly by neutron activation analysis. Sample and data processing can be minimal and conditions can be adjusted according to sample type and precision desired. Such determinations have contributed important reference data in support of biomedical and archaeometric studies. Repeatability of measurements can be better than 3% relative overall, and better than 5% even for irregularly shaped samples (based on one standard deviation).

Fluoroquinolones, as a class of broad-spectrum antibiotics, have been detected in both surface and ground waters, and advanced oxidation/reduction processes (AO/RPs) are currently in development to remove these and other pharmaceuticals from wastewater because currently utilized treatment methods have proven to be ineffective. This article reports the reaction kinetics of six common fluoroquinolones with hydroxyl radicals and hydrated electrons, which are the major reactive species involved in AO/RPs. The bimolecular reaction rate constants (M(-1) s(-1)) for orbifloxacin, flumequine, marbofloxacin, danofloxacin, enrofloxacin, and the model compound, 6-fluoro-4-oxo-1,4-dihydro-3-quinoline carboxylic acid, with *OH are (6.94 +/- 0.08) x 10(9), (8.26 +/- 0.28) x 10(9), (9.03 +/- 0.39) x 10(9), (6.15 +/- 0.11) x 10(9), (7.95 +/- 0.23) x 10(9), (7.65 +/- 0.20) x 10(9), and with e(aq)(-), (2.25 +/- 0.02) x 10(10), (1.83 +/- 0.01) x 10(10), (2.41 +/- 0.02) x 10(10), (1.68 +/- 0.02) x 10(10), (1.89 +/- 0.02) x 10(10), and (1.49 +/- 0.01) x 10(10). These rate constants are related to the functional groups attached to the quinolone core, particularly the steric hindrance of the piperazine ring, making it possible to obtain a preliminary estimate of the *OH rate constant of an arbitrary fluoroquinolone by observing the ring constituents. In addition, the products of gamma-irradiation degradation of fluoroquinolones were analyzed by LC-MS to elucidate the probable pathways of AO/RPs degradation. Results indicate that preliminary degradation pathways include hydroxyl radical attack on the aromatic ring with subsequent hydroxylation, the substitution of a fluorine atom with a hydroxyl group, and the removal of the piperazine-derived side chain.

Lead and Ba in postmortem tooth enamel, rib and ulna of six contemporary people (67-96 years; ave. 80) were shown to exhibit similar accumulations with age in the three different types of osseous tissue: Pb/Ca (wt) = 3.0, 5.2, and 3.9 x 10(-5) in rib, ulna, and tooth enamel; and Ba/Ca (wt) = 2.4, 2.4, and 1.8 x 10(-5) in rib, ulna, and tooth enamel, respectively. Mean concentrations of Pb were 11, 19, and 14 micrograms g-1 in rib (ash), ulna (ash), and enamel (dry), respectively. Means for Ba were 8.7, 8.9, and 6.4 micrograms g-1 in rib (ash), ulna (ash), and enamel (dry), respectively. Comparison of Ba in ulna of our 80-year-old subjects with Ba determined by other investigators in bones of younger contemporary populations indicated that Ba accumulates with age at about half the rate of Pb accumulation in bone. Concentrations of Ba in rib, ulna and enamel were positively correlated and similar within an individual, but varied among subjects in proportion to variations in absorptive uptake in portal blood. Barium may diffuse from a blood-dentine source into enamel, where it replaces Ca and accumulates with age. Because of extreme Pb pollution of our 80-year-old subjects and its variation of intake with age, the correlation of Pb in tooth enamel with Pb in bone was more scattered than for Ba. It is shown by means of stable Pb isotopic tracers that: (i) among the three types of osseous tissue, the residence time of Pb is longest in enamel, where it apparently accumulates with age by diffusion with little loss through exchange; and (ii) the residence time of Pb is longer in compact ulna than in trabecular rib, as it accompanies Ca in its osteoblastic transfer from blood to bone and then in its osteoclastic transfer back to blood from bone.

Background . The devaluation of surgical procedural services by Medicare began in 1989 as a result of the federal government's adoption of the Resource Based Relative Value Scale, a method of redistribution of payments to physicians from surgical to primary care services. This method gave to the Health Care Financing Administration (HCFA) effective and complete control of Medicare payments to physicians for the first time. The resultant decrease in the nominal dollar value is well understood, but the effect of changes in inflation frequently is not calculated into the reported loss. Methods . A method of determining the true extent of this devaluation using the nominal dollar decrease plus the effect of inflation was presented in 1995. Results . Since then, repeated devaluation by the HCFA and other third parties plus continual inflation has further eroded the remuneration for cardiothoracic surgical services. Three different sets of data are used to determine the devaluation of five cardiothoracic operations. One set shows the change between 1988 and 1998; one the change between 1988 and 1999; and one the change between 1984 and 1999. Conclusions . Depending on the geographic location, it appears that the remuneration for pulmonary procedures between 1988 and 1999 decreased 35% to 60%. Similarly, depending on the years reviewed (between 1984 and 1999) and the geographic location, the fee for cardiac procedures decreased 46% to 69%.

The vibrations of phosphate (PO 4 -3 ) ions in single crystals of hexagonal Ba 5 (PO 4 ) 3 F have been investigated by means of polarized Raman scattering and compared to Raman frequencies observed in fluorapatite analogs Sr 5 (PO 4 ) 3 F and Ca 5 (PO 4 ) 3 F. The Raman vibrational frequencies decrease upon substitution of Ba 2+ for Sr 2+ or Ca 2+ in the lattice, asymptotically approaching the Raman frequencies for vibrations of the free ion. The observed splitting is in accord with predictions made by a group theory analysis of the factor group of the unit cell. The effects of the host lattice environment on the magnitude of the Davydov splittings and frequency shifts of phosphate ions within different crystals with the fluorapatite structure are demonstrated to be inversely proportional to the unit cell volume.

Surgeons have, over the past 7 years, experienced a significant decrease in valuation of their services. This has been accomplished by use of the Resource-Based Relative Value System, and its interpretation and modification by various agencies of the federal government. Congress recently mandated a study of practice costs that could result in further reductions of up to 30%. In anticipation of this further reduction, it is important to understand in as accurate a way as possible what has happened thus far to the value for surgical services. Simple percentage in decrease of fees is well understood, but their decrease in relation to the cost of a constant market basket of goods has not been well publicized. We present a simple method for determining the change in value for any procedure or service done by a surgeon in relation to the cost of a constant market basket of goods for any period of time from 1970 to 1995. For example, the increase in the cost for the constant market basket of goods between 1972 and 1992 is shown to be 236%. The increase in value for a typical cardiothoracic procedure in the same time period was 52%. The valuation for this procedure has actually declined 55% from 1972 to 1992, relative to the market basket of goods. The service that would buy the complete basket in 1972 will now buy only 45% of the basket.

The Ad Hoc Committee to study the Resource-Based Relative Value Study has been active for more than 2 years. This Committee's membership was initially appointed by The Society for Thoracic Surgeons, but was quickly expanded so as to represent virtually all this nation's surgeons practicing the specialty of cardiothoracic and vascular surgery. This address describes the general activities of the Committee since its organization. It includes: 1.1. A brief description of the resource-based relative value scale (RBRVS). 2.2. The Committee's investigation of Harvard RBRVS Phase I as it relates to our specialty. 3.3. The Committee's findings and resultant testimony to the federal government and the American Medical Association. 4.4. The genesis and conduct of an independent study of the specialty. 5.5. A summary of our current position with respect to federal initiatives.

Samples of sandstones and shales were analysed by instrumental neutron activation analysis for a total of 30 elements. Three irradiation and five counting periods wer employed. Solutions and National Bureau of Standards Reference Materials wer used for comparison. The samples were obtained from drill cuttings (with a few core samples) from drillings in the Salton Sea geothermal field of California. These determinations form part of a major study to elemental variation as a function of mineral variation as depth and temperature in the well vary. The overall goal is to examine mineral alteration and/or element migration under typical geothermal conditions. The techniques involve typical compromises between maximizing precision for individual element determinations and the amount of time and effort that can be expended, as it is desired to examine large numbers of samples. With the limitations imposed by the reactor flux ailable at the U. C. Irvine TRIGA reactor, the detectors available, and time factors, most precisions are acceptable for geological comparison purposes. Some additional measurements wer made by delayed-neutron counting methods to compare with uranium determinations made by conventional instrumental neutron activation analysis methods.

A program of field and laboratory measurements of emissions from the burning of agricultural residues (primarily cereal straw and stubble) and plume behavior is described. Relationships investigated include the dependence of total emissions and plume concentrations on fuel management, field ignition technique and ambient meteorological conditions. Total particulate emissions (by mass) were found to increase strongly with increasing residue moisture content but are reduced to one half through the use of a backfire field ignition technique versus the head fire ignition method. Increased emissions from headfires is attributable to smoldering in the burned over areas. Backfire fuel consumption rates are typically about one-fifth that for headfires, resulting in a further reduction of particle concentrations in backfire plumes. Increased fuel loading reduces emissions, especially for headfires. The mass median diameter of particles from either fire ignition technique is less than 0.2 μm and in the average about one half of these particles are chloroform soluble. CO and gaseous hydrocarbon emissions were also found to be directly proportional to residue moisture content, but independent of field ignition technique. Plume rise is maximized (ground level concentration minimized) by using headfires in light winds (

A blind study of total O content in nine USGS standard rocks G-2, AGV-1, GSP-1, DTS-1, BCR-1, SCo-1, MAG-1, RGM-1 and QLO-1, Reagent Grade oxalic acid and Specpure SiO 2 was performed using the activation method by 14.3-Me V neutrons and a dedicated dual sample transfer and counting system. Over a composition range varying from 43 to 76% O absolute deviation from stoichiometric O varied from 0.07 to 0.88%. A simple computer program was used to calculate the stoichiometric O from chemical analyses of the rocks and to show summations including the FNAA oxygen. Accurate O data permit the evaluation of overall accuracy of rock analysis and help to detect dificiencies, errors, and incomplete work by enabling the chemist to calculate the analysis unambiguously.

An improved Ti:Al/sub 2/O/sub 3/ amplifier model is reported. Amplifier performance under various pump and probe fluence conditions is also reported. It is claimed to be in good agreement with the numerical model predictions. >

The Smeloff aortic valve has remained unchanged in design and material since 1966. To assess the long-term performance of this prosthesis, we reviewed 394 consecutive patients undergoing elective aortic valve replacement. Concomitant coronary artery bypass grafting was performed in 26.4% of these patients. Follow-up was complete in 96%; maximum follow-up was 13.1 years (mean 4.3 years). The operative mortality was 7.4 %. Actuarial survival rate, including operative mortality, was 66.3 % ± 2.8 % at 5 years and 48.7% ± 4.5% at 10 years. Thromboembolism for the entire group occurred at a rate of 3.8% per patient-year. Patients who underwent anticoagulation continuously had a rate of embolision of 1.8% per patient-year. All patients had a 5 year embolus-free rate of 91% ± 2% and a 10 year embolus-free rate of 85% ± 3%. Patients receiving anticoagulants had a 5 year embolus-free rate of 92% ± 2% and a 10 year embolus-free rate of 89% ± 3%. There was no mechanical failure or prosthetic thrombosis in 1,690 patient-years of follow-up. The Smeloff aortic valve has excellent long-term durability and thromboembolism is low in patients receiving anticoagulants.

A microcomputer-based controller for a digital cartridge tape drive is developed. Minimum interface hardware is used to achieve the required control by making the best use of the I/O ports available on a single board computer. The software-intensive approach gives increased reliability and flexibility to the control scheme while keeping the development time short. A simple two-processor multiprocessing configuration is implemented and tested for a real-time data-acquisition system where the digital cartridge tape serves as the mass storage medium. Test/reset semaphores are used to coordinate the operation of the two processors. An initial application to real-time acquisition of aircraft flight data is described.

The results of three studies relevant to the UV photochemistry of cyanoacetylene are reported. Firstly, the absorption cross-section of HC3N between 240 and 188 nm has been measured. Secondly, the heat of formation of the C3N radical has been experimentally determined to be 629 ± 17 kJ mol−1. This implies a dissociation threshold of 244 ± 8 nm for HC3N. Finally, the quantum yield for the process at 193 nm is found to be about 0.05. These three experiments point to as the major process in the UV photolysis of cyanoacetylene.

Two hundred fourteen survivors of single aortic (AVR) or mitral valve replacement (MVR) were evaluated. The present model of the Smeloff-Cutter prosthesis was used in these patients, and the series was started in September, 1966, following the last structural change in the valve. Clinical follow-up ended in September, 1976. Bleeding, thromboembolism, and peristent left ventricular dysfunction were the major complications. Thromboembolism occurred at a rate of 0.13 percent per month of patient follow-up. Late deaths occurred in 19.2 percent of patients, half of these within the first year. Actuarial data indicated a 5 year survival rate of approximately 75 percent after both mitral and aortic replacements. Bleeding and thromboembolism were more frequent causes of death after mitral replacement. Myocardial function was of greatest importance in long-term survival after replacement of either valve. Variations in warfarin dosage significantly affected both bleeding and thromboembolic complications.

Oxygen was determined accurately in eight U.S. Bureau of Mines coal ash samples A, B, D, F, G, I, and J, NBS coal fly ash 1633 reference material, and two low-temperature ashes (LTA) from lllinois State Geological Survey. The method uses fast-neutron activation (FNA) analysis employing a dual counting and irradiation system which is essentially free from interferences. The stoichiometric balance based on analyses of the ashes performed by the USBM is calculated and summations given in oxide and element percent. Excellent agreement is found with the chemical data obtained by classical silicate analysis methods. Accurate oxygen determination for coal ash and LT-ash (or mineral matter) is important for calculation of data in the ultimate analysis of coal as such. Knowledge is required for recalculation of the data on a dry and dry-ash-free basis. The routinely used ‘oxygen by difference’ values are inadequate for accurate work. In order to determine the organic oxygen in coal one also has to correct for oxygen in mineral matter and oxygen in the water removed as moisture. The Parr formula and other methods of empirical estimation are inadequate and may be replaced in some cases by the oxygen determination. The complete data provide a quantitative basis for stoichiometric interpretation of coal analyses. It was found that the eight coal-ash samples analysed contained 45.5 ± 3% oxygen. Since these ashes represent a large variety of U.S. coals, this figure can be used as an estimate for recalculation and evaluation of the proximate and ultimate coal analyses. It is better, however, to use values actually determined in ash by the rapid fast-neutron activation method. This permits a better estimation of the sum of cations plus sulphates in the ash.

Oxygen is determined by fast-neutron activation with high accuracy in reagent grade compounds: H 2 O (distilled), Li 2 CO 3 , BeO, (COOH) 2 · 2H 2 O, Na 2 CO 3 , NaHCO 3 , Na 2 C 2 O 4 , C 6 H 5 (COOH), (NH 4 ) 2 C 2 O 4 · H 2 O, MgO, Al 2 O 3 , SiO 2 , Fe(SO 4 ) · 7H 2 O, Fe(NH 4 ) 2 (SO 4 ) 2 · 6H 2 O, BaCl 2 · 2H 2 O, K 2 CO 3 , KMnO 4 , K 2 Cr 2 O 7 , CaCO 3 , TiO 2 , V 2 O 5 , Cr 2 O 3 , MnO 2 , Fe 2 O 3 , CuO, NiO, Co 2 O 3 , ZnO, GeO 2 , As 2 O 5 , RbHCO 3 , SrCO 3 , Y 2 O 3 , ZrO 2 , Nb 2 O 5 , Na 2 MoO 4 · 2H 2 O, CdCO 3 , SnO, Sb 2 O 3 , CsHCO 3 , La 2 O 3 , PrO 1.818 ∗3 , Ta 2 O 5 , WO 2 , WO 3 , HgO (yellow), HgO (red), Tl 2 O 3 , Pb 3 O 4 , PbO, and Bi 2 O 3 . Standard deviation in the range of 0.1–0.3% is achieved. Data are plotted vs. theoretical oxygen percentages and a linear curve is obtained for compounds ranging from hydrogen to bismuth and for oxygen concentrations from 7.17% (PbO) to 88.81% (H 2 O). This work demonstrates the high precision and accuracy of the method and suggests numerous applications not previously considered.

Oxygen was determined in six coals from the Wyodak Bed, Campbell County, Wyoming. Data from the U.S. Bureau of Mines' coal analysis reports were used to calculate the material balance of these coals based on accurate oxygen determination by a fast-neutron activation method developed at the University of California, Irvine. A computer program recalculates the data based on moisture determined in our laboratory and tabulates the results, comparing the ‘oxygen by difference’ to oxygen determined on ‘as received’ basis. Oxygen in samples dried at 105 °C was also determined in order to estimate the possible effect of oxidation and loss of volatile components other than water during the drying process. Summations of all data were derived using the accurate oxygen values determined. This approach permits a better interpretation of stoichiometry of coal analysis. The completeness of an analysis can be thus evaluated rapidly. One may be able to indicate and pinpoint probable errors in the determination of sulphur and nitrogen in coal, also the presence of considerable CaCO3. The gross effect of evolution of CH4 and gases other than H2O can be detected. One also is able to estimate the composition of the coal ash and the low-temperature ash as well as the mineral matter (Parr basis) in terms of their varying total oxygen and cation contents. This work shows that five of these six soft, water-rich, coals (20–31% H2O, 105 °C) do balance well stoichiometrically. One coal does not balance based on USBM moisture data. This is apparently due to an error in the moisture determination because oxygen data on this ‘as received’ versus ‘dried, 105 °C’ coal match very closely. It is shown how adding the oxygen determination to routine coal analysis may permit the coal chemist to interpret the data better in terms of true material balance. Oxygen is the only major constituent not routinely determined during the ultimate coal analysis. Adding this element permits the chemist to ascertain the accuracy of the analysis, completes the analysis in the sense of stoichiometry, and makes the customary summations of coal analysis more meaningful.

BALING of rice straw, either in rectangular or big roll bales provides the most adaptable system available for collection and removal of straw from rice fields following combining. Commercial models of balers were evaluated for operating characteristics, capacities, and economics. Bale handling, storage and transport were evaluated for both types of bales.

In the fall of 1982, we conducted a serosurvey of 920 of 933 employees in a large residential institution for the mentally retarded in Salem, Oregon. This survey demonstrated an overall prevalence of 10% for antibody to hepatitis B core antigen (anti-HBc), a marker of present or previous hepatitis B virus infection. Antibody positivity was significantly associated with a history of ever having worked in a position involving direct patient care (adjusted odds ratio = 3.1, 95% confidence interval 2.6-4.2). The length of time employed at the institution was significantly associated with an increasing prevalence of anti-HBc positivity among those persons who had ever worked in direct patient care (χ 2 for linear trend = 19.3, P

The purpose of this panel discussion is to identify qualitative progress made in continuing medical education during the last decade. G. E. Miller found no such progress during the two prior decades, but the panelists adduce the following instances of progress since 1974. The first and second panelists claim progress has been made in the area of identifying and encouraging potential lifelong learners during their formal education: L. K. Gunzburger identifies characteristics of lifelong learners in students entering, attending and leaving medical school and during their later careers. R. D. Fox both identifies an attitude of advocacy for lifelong learning in the medical school curriculum and gives examples of how students and residents are now being prepared for lifelong learning. The third and fourth panelists describe a number of individualized activities now available to practicing physicians: B. Gerbert writes on individualized self-assessment methods, and M. O. Hotvedt describes individualized CME programs. In the panelists' view, the use of individualized assessments and programs has been accepted in the last decade. As commentator, G. E. Miller expresses skepticism about the importance or originality of the progress claimed by the panelists.

It is not clear whether glutathione (GSH) conjugation to 1,2-dibromo-3-chloropropane (DBCP) results in genotoxic activation. Therefore S9, cytosolic, and microsomal fractions from uninduced rat liver were evaluated for their relative ability to activate DBCP in a modified Ames system. The S9 enzymes, either alone or in combination with exogenous GSH, did not enhance the mutagenicity of DBCP; identical results were obtained with cytosolic enzymes. Significant mutagenic activation of DBCP was produced by either S9 or microsomal fractions in the presence of NADPH. Activation was proportional to cytochrome P-450 concentrations, and was diminished by exogenous GSH. The protection against genotoxicity exerted by GSH did not require cytosolic glutathione S-transferases (GST). Thus, mutagenic activation of DBCP as obtained with S9 fractions is primarily due to biotransformation by microsomal rather than by cytosolic enzymes. Kinetic studies of cytosol-catalyzed conjugation of GSH to DBCP revealed tissue-specific differences in apparent Km and Vmax. Renal and testicular GSTs were associated with 28-46% smaller Vmax values when compared to hepatic GSTs (31.2 +/- 1.9 nmol/min X mg protein). However, renal and testicular GSTs had relatively higher affinities for DBCP. Thus, extrahepatic tissues possess significant capacity to conjugate GSH to DBCP. DBCP-GSH conjugates may undergo enzymatic modification by extrahepatic peptidase and beta-lyase to yield other sulfur-containing moieties that perhaps mediate DBCP's extrahepatic toxicity.

Chemical coal analysis can be supplemented by the determination of oxygen in high- and low-temperature ash, in coal as received, and in dried coal at 105 °C. The rapid method utilizes fast-neutron activation. The reaction 16 O(np) 16 N and counting of the 6.1 and 7.1 MeV gamma radiation of 7.3 s half-life are used. A specially designed dual transfer and simultaneous counting system gives very accurate results. Oxygen in 33 coals ranging from lignite to low-volatile bituminous coal has been determined and results are compared with ‘oxygen by difference’. Considerable discrepancies are observed. Better stoichiometric results are obtained if oxygen in coal ash, in wet coal and the dried coal is determined. This permits the estimation of the true material balances in fuels using data of the ultimate and the proximate coal analysis. The oxygen determination provides the coal chemist with an accurate basis and can be used to rank coal. The summation of the percent of carbon, nitrogen, hydrogen, sulphur and oxygen becomes more meaningful, some errors can be detected, and the state of completeness of coal analysis can be evaluated. Total sulphur can be estimated and oxidation effects during drying can be detected. These affect the moisture determination. It appears that after more data have been collected the interpretation of solid fuel analyses may be facilitated and will be made stoichiometrically more meaningful; the ranks of different coals and other properties such as O C plots will become better defined. This approach may help the coal industry in general to quantize further the energy generating processes. It may be possible to simplify the present time-consuming methods of coal analysis. A brief overview of coal analysis methods in relation to direct determination of oxygen is given ‡ .

The purpose of this project was to develop a computer-aided simulation of the clinical encounter (CASE) which offers a student the opportunity to assume the role of a practicing physician, actively engaging in the process of clinical decision-making and observing the consequences of those decisions. The most significant technical accomplishment of the project is a solution to the natural language problem which allows the student to interact with any CASE without being restricted in the use of his own language for inquiry. This paper describes the techniques designed into CASE to allow for the understanding and responding to free English inquiry.

1.1. Pyribenzamine has potent antianaphylactic activity as demonstrated by passive anaphylactic experiments in guinea pigs. 2.2. Pyribenzamine has no demonstrable effect on precipitin titer. 3.3. Pyribenzamine has no demonstrable effect on the complement titer of guinea pigs. 4.4. Pyribenzamine administered orally to human beings decreased the size of histamine skin wheals in 18 of 28 subjects. 5.5. Pyribenzamine (oral) diminished the skin reactivity in 14 of 24 allergic patients. 6.6. Pyribenzamine reduced the reactivity of skin sites passively sensitized with serum containing cottonseed reagins.

n/a