Thermodynamics of the system NaF-AIF3: Part VI. revision

Literature data are reviewed to derive enthalpies and entropies of Na₃AlF₆ and NaF, and they are combined with electrochemical and equilibrium data to yield free energies of formation of Na₃AlF₆ from the constituent fluorides. Liquidus data and measurements of the Na content of Al in equilibrium with the melts then enable the calculation of the free energy of formation, enthalpy, and entropy of all mixtures liquid at 1293 K. In stoichiometric Na₃AlF₆ at 1293 K, a_NaF =0.37 and a_{AlF 3} = 4.9 × 10⁻⁴. The activity coefficient of Na in dilute solution in Al is given byRT ln γ_Na = (40 967 + 9.480 T) J. At 1293 K the partial pressure of NaAlF₄ is given by pNaA1F₄/bar = 27a_NaF . a_{Aif 3}- A heavier species— suggested to be NaAl₃F₁₀—is present in the vapor above AlF₃-rich melts.     

Pessimism, age, and cancer mortality.

Cancer patients (N?=?238) receiving palliative radiation treatment were followed for 8 months; 70 patients had died by the 8-month follow-up. Controlling for site of cancer and level of symptomatology at baseline, the authors studied the independent effects on mortality of pessimism, optimism, and depression. The findings show that the endorsement of a pessimistic life orientation is an important risk factor for mortality, but only among younger patients (ages 30–59). Attempts to replicate this finding with conceptually related constructs such as depression or optimism did not yield significant associations for either younger or older patients, suggesting that negative expectations about the future may contribute to mortality in unique ways. The authors conclude that attempts to link psychosocial factors to mortality should focus on specific psychological constructs instead of diffuse, global measures that cover many psychological phenomena and that the role of psychological processes in mortality may vary dramatically depending on age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cumulative radiation effect. Part VI: simple nomographic and tabular methods for the solution of practical problems

In five previous papers, the concept of the Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage. The biological effect generated in normal connective tissue by fractionated or continuous radiation therapy given in any temporal arrangement is described by the CRE on a unified scale of assessment, so that a unique value of the CRE describes a specific level of radiation effect. The basic methods of evaluating CREs were shown in these papers to facilitate a full understanding of the fundamental aspects of the CRE-system, but these methods can be time-consuming and tediuous for complex situations. In this paper, simple nomographic and tabular methods for the solution of practical problems are presented. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature is introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations are derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluations of CREs for each schedule results in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples.     

Drinking water and cancer mortality in Louisiana

Multivariant regression analysis indicates a statistically significant relation between cancer mortality rates in Louisiana and drinking water obtained from the Missippi River. This is true for total cancer, cancer of the urinary organs, and cancer of the gastrointestinal tract.     

The cancer mortality scare. Problems of estimation using monthly data

Considerable attention has been given recently to an apparent 5.2% rise in cancer mortality, based on data for the first seven months of 1975 as reported to the National Center for Health Statistics (NCHS). Later data disclosed that the rise in crude total cancer mortality, while greater than in any recent year, is less than half of the 5.2% originally reported, and the rise in age-adjusted total cancer mortality, while less than 1%, is also higher than the average annual increase from 1968 to 1974. The Monthly Vital Statistics Report provides death rates not standardized for age, race, and sex, and does not include information for specific cancer sites. Therefore, although information in the Monthly Vital Statistics Report is useful for detecting sudden increases in mortality from acute epidemics, it is not appropriate for forecasting trends in cancer mortality.     

Substance abuse issues in cancer patients. Part 1: Prevalence and diagnosis

Although rare, drug abuse problems present a complex set of physical and psychosocial issues that complicate cancer treatment and pain/ symptom management. Most oncologists are not be well versed in either the conceptual or practical issues related to addiction. As a result, they often struggle in their attempts to effectively treat patients who are or have been substance abusers, and they find it difficult to understand issues of addiction in patients with pain who have no history of substance abuse. In the first installment of a two-part series, the authors explore the epidemiology of substance abuse. An examination of the distinctions between abuse and dependence leads to definitions of these terms appropriate for the oncology setting. Guidelines for assessing aberrant drug-taking behavior are also offered. Part 2, which will appear in the next issue of ONCOLOGY, will discuss the clinical management of cancer patients with a history of substance abuse.     

Substance abuse issues in cancer patients. Part 2: Evaluation and treatment

The relationship between the therapeutic use of potentially abusable drugs for symptom control and the multifaceted nature of abuse and addiction is extremely complex. Research is only beginning to elucidate the nature of this relationship and its clinical implications. At present, practical management is based primarily on clinical experience and anecdotal observations. In part I of this two-part series (published last month), the authors explored the epidemiology of substance abuse in the cancer population, provided definitions of addiction and abuse appropriate for the oncology setting, and offered guidelines for the assessment of aberrant drug-taking behavior. In this second part, the authors provide recommendations for the evaluation and treatment of patients with cancer who have a history of substance abuse. Suggested therapeutic goals are outlined, and plans for inpatient and outpatient management and detailed.     

Oral management of the cancer patient. Part II: chemotherapy

This second of a three-part series reviews chemotherapy treatment and the responsibilities dental care providers have for patients in all phases of this type of cancer treatment. The goals of dental care are to maintain the integrity of the oral mucosa, prevent secondary infection, provide relief, and assist in maintaining dietary intake. The dental hygienist plays a key role in the recognition, treatment or monitoring of dental conditions that could cause complications to the patient during and post chemotherapy, as well as in educating and motivating the patient in optimal oral self-care.     

Selenium concentration and activity of glutathione peroxidase in lysate of human erythrocytes

The concentration of selenium in human red cells was measured by a fluorometric determination method after wet digestion of the biological material. In the red cells from the same blood samples the activity of the selenoenzyem glutathione peroxidase (EC 1.11.1.9) was determined with tertiary butyl hydroperoxide as acceptor substrate. The results show that only 10% of the total selenium content of human red cells is fixed to the enzyme. No correlation between the enzyme activity and the selenium concentration could be found. On the basis of these results can be presumed that the protective effect of selenium in glutathione peroxidase against oxidant damage of cells is not the only biological function of this element.