Evaluation of leaf water status by means of permittivity at terahertz frequencies.

We present an electromagnetic model of plant leaves which describes their permittivity at terahertz frequencies. The complex permittivity is investigated as a function of the water content of the leaf. Our measurements on coffee leaves (Coffea arabica L.) demonstrate that the dielectric material parameters can be employed to determine the leaf water status and, therefore, to monitor drought stress in plant leaves. The electromagnetic model consists of an effective medium theory, which is implemented by a third order extension of the Landau, Lifshitz, Looyenga model. The influence of scattering becomes important at higher frequencies and is modeled by a Rayleigh roughness factor.

Germination of coffee seeds and its significance for coffee quality.

Besides genotypic characteristics, the crucial factor that determines coffee quality is the mode of post-harvest treatment, i.e., the wet and dry processing. Up to now, the resulting characteristic flavour differences between these differentially processed coffees were attributed exclusively to differences in starting material. However, as these quality differences are still evident, even when identical coffee samples were processed by the two methods in parallel, the differences must be created by metabolic processes in the coffee beans themselves. Based on expression studies of the germination-specific isocitrate lyase and the resumption of cell cycle activity, monitored by the abundance of beta-tubulin, we evidence that germination is initiated in coffee seeds during the course of standard coffee post-harvest treatments. The extent and nature of the germination processes depend on the processing method. The coherence of metabolic events, substantial differences in the chemical composition of the coffee beans, and the generation of specific coffee qualities establishes the basis for a quite novel approach in coffee research.

The medical management of unintentional radionuclide intakes.

As a general medical problem, radionuclide intakes that may cause significant health effects are uncommon events. In preparing to manage a radionuclide accident, planning is the key. The medical aspects of such an accident are only one part of the management, and a professional team approach is required. Specific priorities and sequencing are necessary in medically managing a radionuclide intake. As soon as is reasonably practical, promptly remove the victim(s) from further radionuclide, radiation field, or chemical exposure. Life and limb-saving medical aid takes precedence over ionising radiation concerns in nearly all cases. Next are the prevention and/or minimisation of internal intake of radionuclides and evaluation and control of external radionuclide contamination, followed by institution of treatment to minimise the retained radionuclide. Communication with the accident victim, and his or her family, and public affairs/media issues are important. Finally, follow-up treatment for internal intakes that may cause delayed health effects is given.

Postmortem tissue contents of 241Am in a person with a massive acute exposure.

241Am was determined radiochemically in the tissues of USTUR Case 246, a 76-y-old man who died of cardiovascular disease 11 y after massive percutaneous exposure following a chemical explosion in a glove box. This worker was treated extensively with a chelation drug, DTPA, for over 4 y after exposure. The estimated 241Am deposition at the time of death was 540 kBq, of which 90% was in the skeleton, 5.1% in the liver, and 3.5% in muscle and fat. Among the soft tissues, the highest concentrations were observed in liver (22 Bq g-1), certain cartilaginous structures such as the larynx (15 Bq g-1) and the red marrow (9.7 Bq g-1), as compared with the mean soft tissue concentration of approximately 1 Bq g-1. Concentration in muscle was approximately that of the soft tissue average, while concentrations in the pancreas, a hilar lymph node and fat were less than the average. Concentrations in bone ash were inversely related to the ratio of ash weight to wet weight, a surrogate for bone volume-to-surface ratio. The distribution of activity in this case is reasonably consistent with that observed in another human case, when allowance is made for chelation therapy, and also tends to support more recent models of 241Am metabolism.

A randomized comparison of Worksite-sponsored smoking cessation programs.

This worksite study assesses the relative effectiveness of three smoking cessation programs. Computerized medical files indicated that 29% of 13,171 employees were current smokers. Of smokers responding to a worksite-wide survey, 79% indicated interest in a smoking cessation program; 402 smokers agreed to participate and were randomly allocated, within their preference for a group or self-help approach, to the three different programs. Overall, 11% of smokers participated, an excellent rate for a large worksite. Participants were followed for 12 months (91% follow-up). Smokers in the group preference had better short-term results than did those following the self-help approach. The Multiple Component Program had 61% who quit, the Relapse Prevention Program had 37%, and the American Cancer Society Quitter's Guide had 12%. Long-term quit rates ranged from 16% to 26%; all groups exceeded the usual spontaneous quit rate of 5%.

The probability that a specific cancer and a specified radiation exposure are causally related.

It is fundamental that a given cancer case cannot be attributed with absolute certainty to a prior ionizing radiation exposure, whatever the level of exposure. It is possible to estimate the probability of a causal relationship based on data and models that have been inferred from group statistics. Two types of information are needed to make these probability calculations: natural cancer incidence rates and risks of cancer induction from ionizing radiation. Cancer incidence rates for the United States are available in the report of the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute. Estimates of the risk of cancer induction from ionizing radiation have been published by the Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR) of the National Academy of Sciences, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), and the International Commission on Radiological Protection (ICRP). Using the parameters discussed above, the probability of causation formulation estimates the probability that a person who develops a particular cancer after a known quantifiable radiation exposure has the cancer as a result of the exposure. In 1985, the National Institutes of Health, responding to a U.S. Congressional mandate, published radioepidemiologic tables using the probability-of-causation method.

The U.S. Transuranium Registry report on the 241Am content of a whole body. Part I: Introduction and history of the case.

The first whole-body analysis of the U.S. Transuranium Registry was initiated in 1979. The donor was a 49-yr-old male Caucasian radiochemist who died of metastatic malignant melanoma. The donor had a recognized, longstanding 241Am internal deposition first identified in a routine urine sample in 1958. A summary of the clinical and postmortem findings is presented with the chronologic sequence of the procedures.

1976 Hanford americium exposure incident: medical management and chelation therapy.

A chronological account is given of the general medical management of a patient involved in an americium exposure incident.

1976 Hanford americium exposure incident: external decontamination procedures.

An accident resulted in the deposition on an injured workman's skin surfaces, in acid-burned areas and in lacerations, of something in excess of 6 mCi 241Am. This paper describes the external decontamination procedures used, the change in americium content of the skin during the course of treatment, and some of the unusual problems encountered from the extrusion of foreign material and flaking of skin and scar tissue.

1976 Hanford americium exposure incident: decontamination and treatment facility.

An injured worker, contaminated with more than 6 mCi of 241Am required special treatment and housing for 4 months. This paper is a description of the design and management of the facility in which most of the treatment and housing occurred. The problems associated with contamination control, waste handling, supplies and radiological concerns during the two-stage transfer of the patient from a controlled situation to his normal living environment are discussed in detail.

1976 Hanford americium exposure incident: hematologic effects.

Hematologic evaluation of an individual with an initial systemic body burden of approximately 200 mu Ci 241Am revealed a significant (P less than 0.01) reduction of total leukocytes, neutrophils and lymphocytes. This effect on total leukocytes and neutrophils was evident approximately 30 days after exposure, appeared to stabilize at about 3 months after exposure, and remained at this lower level through a 52-month observation period. The effect on lymphocytes was apparent by 3 days after exposure, stabilizing at approximately 50% of pre-exposure values for about 7 months, with a return to pre-exposure levels in the following 4 yr. There was a progressive and significant (P less than 0.001) decline in platelet counts during the 52-month post-exposure period. The pattern of response in erythrocyte parameters was complex. Immediately after the accident, these values were less than the pre-exposure mean level; they gradually increased (P less than 0.001) for approximately 2 yr and then began a progressive decline (P less than 0.001).

The U.S. Uranium Registry tissue program.

The U.S. Uranium Registry tissue program was established in December 1980. It is patterned after the U.S. Transuranium Registry program. Both are funded by DOE. The objectives of the program are to: (1) detect the presence and distribution of uranium, if any, in human tissue in occupationally exposed workers, (2) compare bioassay and in vivo measurements for exposed individuals with the results of analysis of tissue obtained at autopsy, (3) seek evidence of histopathological changes related to any uranium deposition found, (4) conduct analyses of whole bodies, when available, to obtain more precise data on the uranium burdens, if any, in the body and organs, and especially the distribution in parts of the body, such as most of the skeleton, that are not usually accessible for sampling. The program will include (1) participants who have been permissibly exposed, (2) participants who were exposed at a time when current limits did not exist and (3) reference individuals without exposure. The program will develop data that will assist in evaluating (1) the accuracy of current in vivo measurement techniques, (2) the propriety of existing regulations and (3) the adequacy of current protection programs. Enrollment in the program is voluntary.