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All-sky imager based systems can be used to measure a number of cloud properties. Configurations consisting of two all-sky imagers can be used to derive cloud heights for weather stations, aviation and nowcasting of solar irradiance. One key question for such systems is the optimal distance between the all-sky imagers. This problem has not been studied conclusively in the literature. To the best of our knowledge, no previous in-field study of the optimal camera distance was performed. Also, comprehensive modeling is lacking. Here, we address this question with an in-field study on 93 days using 7 camera distances between 494 m and 2562 m and one specific cloud height estimation approach. We model the findings and draw conclusions for various configurations with different algorithmic methods and camera hardware. The camera distance is found to have a major impact on the accuracy of cloud height determinations. For the used 3 megapixel cameras, cloud heights up to 12,000 m and the used algorithmic approaches, an optimal camera distance of approximately 1500 m is determined. Optimal camera distances can be reduced to less than 1000 m if higher camera resolutions (e.g. 6 megapixel) are deployed. A step-by-step guide to determine the optimal camera distance is provided.

This chapter provides an overview of MA especially concerning the negotiation of the purchase agreement, bearing in mind the potential transaction risks arising from IP. The chapter concludes by illustrating the increasing relevance of recent developments concerning IP transactions, e.g., patent/innovation box regimes.

In the field of hearing research a variety of imaging techniques are available to study molecular and cellular structures of the cochlea. Most of them are based on decalcifying, embedding, and cutting of the cochlea. By means of scanning laser optical tomography (SLOT), the complete cochlea can be visualized without cutting. The CaWhole undissected cochleae from CaVisualization by SLOT showed that the staining of nerve fibers at P27 in CaThe visualization of whole non-dissected cochleae by SLOT is a suitable tool for the analysis of gross phenotypic changes, as demonstrated by means of the Ca

Printed Circuit Boards (PCB) play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. Photogrammetry is an image based method for three dimensional reconstruction from two dimensional image data of an object. A precise camera calibration is indispensable for an accurate reconstruction. In our certain application it is not possible to use calibration methods with two dimensional calibration targets. Therefore a special calibration target was developed and manufactured, which allows for single image camera calibration.

The dual-hit hypothesis of neurodegeneration states that severe stress sensitizes vulnerable cells to subsequent challenges so that the two hits are synergistic in their toxic effects. Although the hippocampus is vulnerable to a number of neurodegenerative disorders, there are no models of synergistic cell death in hippocampal neurons in response to combined proteotoxic and oxidative stressors, the two major characteristics of these diseases. Therefore, a relatively high-throughput dual-hit model of stress synergy was developed in primary hippocampal neurons. In order to increase the rigor of the study and strengthen the interpretations, three independent, unbiased viability assays were employed at multiple timepoints. Stress synergy was elicited when hippocampal neurons were treated with the proteasome inhibitor MG132 followed by exposure to the oxidative toxicant paraquat, but only after 48 h. MG132 and paraquat only elicited additive effects 24 h after the final hit and even loss of heat shock protein 70 activity and glutathione did not promote stress synergy at this early timepoint. Dual hits of MG132 elicited modest glutathione loss and slightly synergistic toxic effects 48 h after the second hit, but only at some concentrations and only according to two viability assays (metabolic fitness and cytoskeletal integrity). The thiol N-acetyl cysteine protected hippocampal neurons against dual MG132/MG132 hits but not dual MG132/paraquat hits. These findings support the view that proteotoxic and oxidative stress propel and propagate each other in hippocampal neurons, leading to synergistically toxic effects, but not as the default response and only after a delay. The neuronal stress synergy observed here lies in contrast to astrocytic responses to dual hits, because astrocytes that survive severe proteotoxic stress resist additional cell loss following second hits. In conclusion, a new model of hippocampal vulnerability was developed for the testing of therapies, because neuroprotective treatments that are effective against severe, synergistic stress are more likely to succeed in the clinic. © 2016 Wiley Periodicals, Inc.

The dual-hit hypothesis of neurodegeneration states that severe stress sensitizes vulnerable cells to subsequent challenges so that the two hits are synergistic in their toxic effects. Although the hippocampus is vulnerable to a number of neurodegenerative disorders, there are no models of synergistic cell death in hippocampal neurons in response to combined proteotoxic and oxidative stressors, the two major characteristics of these diseases. Therefore, a relatively high-throughput dual-hit model of stress synergy was developed in primary hippocampal neurons. In order to increase the rigor of the study and strengthen the interpretations, three independent, unbiased viability assays were employed at multiple timepoints. Stress synergy was elicited when hippocampal neurons were treated with the proteasome inhibitor MG132 followed by exposure to the oxidative toxicant paraquat, but only after 48 h. MG132 and paraquat only elicited additive effects 24 h after the final hit and even loss of heat shock protein 70 activity and glutathione did not promote stress synergy at this early timepoint. Dual hits of MG132 elicited modest glutathione loss and slightly synergistic toxic effects 48 h after the second hit, but only at some concentrations and only according to two viability assays (metabolic fitness and cytoskeletal integrity). The thiol N-acetyl cysteine protected hippocampal neurons against dual MG132/MG132 hits but not dual MG132/paraquat hits. These findings support the view that proteotoxic and oxidative stress propel and propagate each other in hippocampal neurons, leading to synergistically toxic effects, but not as the default response and only after a delay. The neuronal stress synergy observed here lies in contrast to astrocytic responses to dual hits, because astrocytes that survive severe proteotoxic stress resist additional cell loss following second hits. In conclusion, a new model of hippocampal vulnerability was developed for the testing of therapies, because neuroprotective treatments that are effective against severe, synergistic stress are more likely to succeed in the clinic. © 2016 Wiley Periodicals, Inc.

Clouds are the dominant source of variability in surface solar radiation and uncertainty in its prediction. However, the increasing share of solar energy in the world-wide electric power supply increases the need for accurate solar radiation forecasts. In this work, we present results of a shortest-term global horizontal irradiance (GHI) forecast experiment based on hemispheric sky images. A two month dataset with images from one sky imager and high resolutive GHI measurements from 99 pyranometers distributed over 10 km by 12 km is used for validation. We developed a multi-step model and processed GHI forecasts up to 25 min with an update interval of 15 s. A cloud type classification is used to separate the time series in different cloud scenarios. Overall, the sky imager based forecasts do not outperform the reference persistence forecasts. Nevertheless, we find that analysis and forecast performance depend strongly on the predominant cloud conditions. Especially convective type clouds lead to high temporal and spatial GHI variability. For cumulus cloud conditions, the analysis error is found to be lower than that introduced by a single pyranometer if it is used representatively for the whole area in distances from the camera larger than 1–2 km. Moreover, forecast skill is much higher for these conditions compared to overcast or clear sky situations causing low GHI variability which is easier to predict by persistence. In order to generalize the cloud-induced forecast error, we identify a variability threshold indicating conditions with positive forecast skill.

The olfactory bulb is one of the most vulnerable brain regions in age-related proteinopathies. Proteinopathic stress is mitigated by the heat shock protein (Hsp) family of chaperones. Here, we describe age-related decreases in Hsc70 in the olfactory bulb of the female rat and higher levels of Hsp70 and Hsp25 in middle and old age than at 2-4 months. To model proteotoxic and oxidative stress in the olfactory bulb, primary olfactory bulb cultures were treated with the proteasome inhibitors lactacystin and MG132 or the pro-oxidant paraquat. Toxin-induced increases were observed in Hsp70, Hsp25, and Hsp32. To determine the functional consequences of the increase in Hsp70, we attenuated Hsp70 activity with two mechanistically distinct inhibitors. The Hsp70 inhibitors greatly potentiated the toxicity of sublethal lactacystin or MG132 but not of paraquat. Although ubiquitinated protein levels were unchanged with aging in vivo or with sublethal MG132 in vitro, there was a large, synergistic increase in ubiquitinated proteins when proteasome and Hsp70 functions were simultaneously inhibited. Our study suggests that olfactory bulb cells rely heavily on Hsp70 chaperones to maintain homeostasis during mild proteotoxic, but not oxidative insults, and that Hsp70 prevents the accrual of ubiquitinated proteins in these cells. The olfactory bulb is affected in the early phases of many age-related neurodegenerative disorders. Here, we described the impact of aging on multiple heat shock proteins (Hsps), such as Hsp70, in the female rat olfactory bulb in vivo. Using multiple proteasome and Hsp70 inhibitors (see schematic), we found that proteotoxicity elicited a compensatory increase in Hsp70 in primary olfactory bulb cells in vitro. Hsp70 then reduced the proteotoxic buildup of ubiquitinated proteins and robustly protected against cell death according to three independent viability assays. Thus, olfactory bulb neurons can mount impressive natural adaptations to proteotoxic injury, perhaps explaining why neurodegenerative disorders are so delayed in onset and so slow to progress.

Amorphous ceramics with the chemical composition Si3B3N7 and SiBN3C were produced from single-source molecular precursors by polymerization and pyrolysis. The powder and fiber materials were investigated by means of energy filtering transmission electron microscopy. The intensity of elastically scattered electrons is recorded to calculate the pair distribution function of these ceramics. In the pair distribution function of Si3B3N7 three significant maxima at 0.144, 0.172, and 0.291 nm are clearly resolved and are assigned to the pair distances B–N, Si–N, and Si–Si (N–N), respectively, by comparison to crystalline materials. The predominant structural units of the ceramic are trigonal planar BN3 and tetrahedral SiN4 groups, which are close to their regular symmetry. The overall pair distribution function of SiBN3C is very similar to that of Si3B3N7; however, the maxima are broadened due to the incorporation of carbon into the network. High-resolution mapping of the elements Si, B, N, and C with electron spectroscopic imaging reveals a homogeneous distribution on a subnanometer scale without precipitation or separation of, for example, carbon-rich clusters. Similarly, elemental mapping of Si3B3N7 reveals a random distribution of the elements Si, B, and N at the same scale. Both new ceramics consist of an amorphous network with bonds and coordinations as preformed in the precursor.

The finite-element multi-grid method combines the stability and high accuracy of FEM with the ability of MG to solve sparse matrix equations very quickly, scaling basically linear with the number of unknowns. It is applied to effectively two-dimensional problems like atoms and diatomic molecules under axial symmetry described by density and orbital functionals, respectively. The high solution efficiency (accuracy and speed) of FEM-MG obtained already is demonstrated for which in many respects is a particularly difficult case. Thus our finite-element multi-grid method allows large-scale investigations with controlled accuracy of various combinations of exchange-correlation density functionals for the description of lighter atoms and diatomic molecules.

The team approach to geriatric care does not automatically result in appropriate decision making with regard to elderly patients with multiple chronic problems and complicated, overlapping needs. In this article, Janis's (1972, 1982) group‐think theory and tests of facets of the theory are examined. A modified theory is then applied to geriatric health care teams using a case scenario. Suggestions for minimizing the conditions that lead to groupthink and the resultant poor decisions are made. Health care teams need to develop strategies to enhance group cohesiveness and open, democratic leadership and to minimize time constraints and group insulation; rules and procedures for discussing options and making decisions through consensus should be developed and understood by all team members.

Heinemann, D., Ripke, M. and Lucas, K., 1993. Thermodynamic properties of fluid oxygen from the SSR-MPA potential. Fluid Phase Equilibria, 86: 15-25 p] The thermophysical properties of gaseous and liquid oxygen are calculated from an effective potential function including two-centre site-site repulsion, two- and three-body dispersion forces, and the electrostatic and induction interactions arising from the quadru-pole moment. Additionally, quantum corrections are included in the calculation of the dense fluid properties. The potential parameters are adjusted to the experimental second virial and Joule-Thomson coefficients, and to a few liquid pressures between 100 and 130 K. The potential function determined from this very small number of experimental data is used to predict the thermophysical properties of oxygen over a large region of states. The gas data, i.e. Joule-Thomson coefficients as well as second and third virial coefficients, are computed from this potential using an efficient non-product integration formula for multidimensional integrals. In the dense gaseous and liquid range, Monte Carlo simulation provides pressures and internal energies. When first-order quantum corrections are included, the overall accuracy of the computed properties is very satisfactory.

The main characteristics of malignant cells include increased metabolism and capacity for division which are associated with high membrane fluidity.1 Membrane fluidity is in turn controlled by multiple factors which include the ratio of saturated to unsaturated fatty acids in the cell wall i.e. the Saturation Index (SI).2-3 The SI is known to be reduced in neoplastic cells as well as in the circulating erythrocytes of patients with some malignant tumours but not others. It has been suggested that the SI may be useful as a marker of malignancy.

Factors influencing atypical speech lateralization have theoretical importance in understanding the organization and reorganization of higher cognitive functions, as well as having practical implications, especially in brain surgery and neurorehabilitation. Atypical (right‐sided or bilateral) language representation is more frequent in focal epilepsy than in healthy people. This difference is thought to be related to early childhood brain injuries localized in the neighbourhood of speech centres. The effect of epileptic activity on speech lateralization has not been investigated, although much data suggest that epileptic activity may interfere with higher brain functions. It can only be evaluated in a homogeneous human population with epilepsy having the same lesion type in the same localization. For these reasons, we investigated 184 patients with medial temporal lobe epilepsy (MTLE) due to unilateral hippocampal sclerosis (HS), but without other epileptogenic lesions. All patients underwent comprehensive presurgical evaluation. In MTLE, the influence of age at the time of brain damage, i.e. the initial precipitating injury (IPI), could be evaluated separately from the other timing factors. Of 100 patients in whom a Wada test was performed, left‐sided speech occurred in 76% of the left‐sided and in 100% of the right‐sided MTLE patients ( P

The delivery of health care and services via a team approach occurred throughout the twentieth century. As medical specialties developed in the early 1900s, physicians viewed the team approach as a mechanism for coordinating the medical specialties and for keeping lines of communication open between specialists and general practitioners. In the 1930s, nurses began to advocate for the team approach in hospital settings as a means of coordinating the efforts of growing numbers of health professionals and health workers employed there. By the mid 1900s, teams were providing care to chronically ill patients in such areas as home care, mental health, and rehabilitation. President Johnson’s Great Society and War on Poverty Programs of the 1960s gave impetus to teamwork delivered in community-based, primary care settings to poor and under-served, urban populations.

List of Tables. Editors. List of Contributors. Foreword. Preface. Part I: Conceptualizing Model and Measurement. 1. Teams in Health Care Settings G.D. Heinemann. 2. Measuring Team Performance in Health Care Settings A.M. Zeiss. 3. A Model of Team Performance G.D. Heinemann, A.M. Zeiss. 4. Organizational and Team Structure S.A. Brallier, R.A. Tsukuda. 5. Organizational and Team Context S.K. Harmon, S.A. Brallier, G.F. Brown. 6. Team Process L.O. Nichols, A.M. Defriese, C.C. Malone. 7. Team Productivity M.S. Waite, S.B. Hoffman. Part II: Reviewing and Evaluating Team Performance Instruments. 8. Critiquing and Summarizing Instruments S. Brallier, S. Lovett, T.F. Miller. 9. Focused Instruments R.A. Tsukuda. 10. Middle-Range Instruments S.B. Hoffman. 11. Broad-Spectrum Instruments M.S. Waite, L.O. Nichols. 12. Full-Spectrum Instruments G.F. Brown, E.P. Mahairas. 13. Instruments for Health Care Teams G.F. Brown, M.S. Waite. 14. Assessment and Development: Now and in the Future S. Lovett, A.M. Zeiss, G.D. Heinemann. Index.

Team performance is a multifaceted concept; therefore, it is essential to delineate a comprehensive model capturing all of its facets. In reviewing literature on teams and teamwork, we were unable to find a model that identifies the major components of performance and the relationships among them. In this chapter, we describe our process of developing such a model and present an overview of the domains and dimensions of the model as they relate to the current changes in the health care system and the growth and evolution of teams. The elements of each dimension of the model are delineated in Chapters 4 through 7.

In this final chapter, we address the state of the field of team performance with respect to assessment, theory, and education/consultation. Initially, we identify the “best measures” from the instruments we have critiqued in Chapters 9 though 12 along with the criteria and rationale for their selection. Instruments critiqued in Chapter 13 that do not currently measure team performance were not included in the selection of “best measures.” Next, we address future measurement of team performance with particular emphasis on what needs to be measured as health care organizations, teams, and technology change and evolve. Changes in measurement include both the development of new instruments and the improvement of current ones. Finally, we discuss how the instruments and the data they provide and our model of team performance can be used to facilitate education and consultation with teams and help them better monitor and evaluate their own development, effectiveness, and performance.

After presenting a theory of team development, we propose that the informal role structure of a team is dependent upon the degree of anomie in the team culture, and we provide measures of anomie and informal roles that can be used in field settings. Then we test hypotheses on a national sample of 111 interdisciplinary health care teams in geriatrics in US Veterans Affairs medical centers. We find evidence that as teams develop from early to later stages, the interpersonal behavior of members becomes less differentiated on three dimensions: prominence, sociability, and task-orientation. In addition, we find that images of each member come into clearer focus, as evidenced by reduced variation in how each member is seen by other team members. Finally, we find that regardless of stage of team development, the more education the team members have, the more prominent and task-oriented they are. In general, physicians score highest in prominence and task-orientation, but relatively low in sociability.

The authors describe the development and psychometric testing across three study phases of an Attitudes Toward Health Care Teams Scale. The measure contains two subscales: Quality of Care/Process (14 items) and Physician Centrality (6 items). The Quality of Care/Process subscale measures team members’ perceptions of the quality of care delivered by health care teams and the quality of teamwork to accomplish this. The Physician Centrality subscale measures team members’attitudes toward physicians’authority in teams and their control over information about patients. Tests of reliability and validity demonstrate that each subscale is a strong measure of its respective underlying concept. The measure has potential for use as a research tool and as a pre-and posttest tool for educational interventions with teams and for evaluating clinically based team training programs for medical and health professions students and residents.

Summary— The red cell membrane stearic acid to oleic acid ratio was analysed in 34 men with histologically proven carcinoma of the prostate and distant metastases. This ratio was expressed as the saturation index (SI). A mean SI of 0.97 was found in control patients without evidence of any malignancy whereas all patients with advanced prostatic cancer showed a reduced stearic to oleic acid ratio (mean SI 0.466). Untreated patients had a significantly lower SI (mean 0.36) than those who had responded to hormonal therapy (mean 0.547; P < 0.0001). A drop in SI correlated well with more advanced disease as judged by radiological findings and serum PSA. It is suggested that red cell membrane SI correlates well with radiological and biochemical markers of advanced prostatic carcinoma and may be used as a marker to assess progress and response to treatment.

This outcomes research used a collaborative framework between a college of nursing and a medical center to test the effects of the Partners in Patient Care delivery model (PIPC) on clinical and nonclinical outcomes. An experimental pretest-postest design was used to compare selected nonclinical outcomes and clinical outcomes of care in two patient units. Results showed that there were significant differences between units in the nonclinical outcomes of nurse satisfaction, salary costs, supply costs, and productivity as measured by documentation time. In addition, there were significant differences in the clinical outcomes of care in terms of patient satisfaction. No significant differences were found in number of falls, medication errors, and intravenous infections; however, when ratios of these indicators were examined in relation to patient days, significant differences in the medication error ratio and the fall ratio were revealed. The results indicate that the PIPC delivery model did have positive effects on patient satisfaction and nurse satisfaction but that there were increased costs and increased time spent in documentation on the pilot unit.

Focus groups facilitate change in healthcare institutions by providing comparative perceptions of all levels of healthcare staff in the environment, obtaining impressions of new options for healthcare delivery for which no information is available, and stimulating new ideas to improve cost-effective quality care. The authors discuss their experience using this data gathering and evaluation approach during the planning and implementation of a new nursing practice model. Factors to consider when using focus groups are offered, and lessons learned from the experience are presented.

An experimental pretest/posttest design compared pilot and control nursing units in a medical center in Southwest Florida to assess the effects of a Partners in Patient Care (PIPC) nursing care delivery model on selected quality of care outcomes-patient satisfaction, patient medication errors, falls, and IV infections. There were no significant differences between units in the number of falls, medication errors, and IV infections. When the ratios of these events to patient days were examined, there was a significant difference between the pilot and control units in the medication error ratio and the fall ratio. The results indicate that the PIPC nursing model had a positive effect on patient satisfaction.

The purpose of this experimental research was to determine the effects of the Partners in Care Practice Model (PIPC) on the outcomes of productivity and costs. Over an 18-month study period, no significant differences were found in costs per patient day between the pilot and control units; however, significant differences were found in actual salaries, amount of time spent in documentation, and supply costs. Differences in costs and productivity reflected increased training costs and costs for additional supplies on the pilot unit.

With the growing use of multiple types of nurse extenders in new patient care-delivery models, there is a need not only for outcome research on their design and use but for identification and discussion of effective team-building processes necessary to implementing these models. This article presents an analysis of the interdisciplinary team process and the levels of team building and processes needed at each level to test a new nursing practice model. The team processes included not only those within the medical center but included the collaborative process established between the college of nursing and medical center. Both of these were crucial to a successful change in nursing practice.

The purpose of this study was to identify the effects of an empirically-designed nursing practice model on the outcome variables of job satisfaction, autonomy, and retention/turnover of nursing staff. After 6 months significant differences were found on the experimental unit in overall job satisfaction, and on the subscales of job satisfaction in task requirements and perception of pay. Significant differences were found between the control and experimental unit on the Job Satisfaction Index subscales of interaction, task requirements, and autonomy. No significant differences were found in retention/turnover of staff between the experimental and control unit.

Several nursing practice models use nurse extenders/partners to extend nurses' time. The authors discuss the development, implementation, and evaluation of the "partner in patient care" (PIPC) model. Unique aspects of the model are emphasized, including use of a collaborative process to generate the design and guide the implementation; staff participation throughout the design and implementation of the project; and use of evaluation at each phase of the implementation process to improve on the outcomes.

Summary— Controversy still exists as to whether oestrogens exert a direct effect on the prostatic cell. Incorporation of 75Selenomethionine (SeM) was used as a measure of protein synthesis by prostatic carcinoma cells in vitro to investigate the action of hormones on prostatic carcinoma cells in tissue culture. Stilboestrol (DES) and stilboestrol diphosphate (Honvan) inhibited protein synthesis in a proportion of patients, while testosterone was stimulatory. A similar effect was noted in cells from patients with benign hyperplasia (BPH). This work confirms that oestrogens have a direct inhibitory effect on prostatic cells at high concentrations which can be attained in patients given intravenous stilboestrol diphosphate.

The goals of this research were to identify predictors of negative health outcomes among the elderly and to specify subgroups or profiles of elderly with similar health outcomes one year after an initial health assessment. A secondary analysis of data, pooled from three studies concerned with the health and long term care of the elderly, was performed using a multivariate, statistical approach. Number of chronic conditions, age, social class, and income were important predictors of the two variables measuring health decline. Variables identified as predictors of mortality and/or paths to death include the following: IADL dependencies, degenerative diagnoses, living arrangements, MSQ, and social class. Profiles of the elderly, resulting from the AID analysis, coincided with research findings presented in the literature. This analysis technique holds promise with regard to targeting appropriate health and long-term care services to subgroups of elderly who could benefit most from them.

Peripheral blood lymphocytes (PBL) were obtained from 13 patients and tumour-intrinsic lymphocytes (TIL) from 20 patients with colorectal cancer. The PBL were separated on a Ficoll-Isopaque gradient and the TIL by digestion of the tumour with collagenase-DNase. Both PBL and TIL were passed through nylon-wool columns and the eluted cells were co-cultured for 2 h with 51Cr-labelled tumour cells from the same patient. If patients in whom spontaneous 51Cr release from the tumour cells was greater than 33% were excluded, PBL showed cytotoxicity for the autoplastic tumour cells in 5/10 cases and TIL in 3/10 cases (NS). In 12 cases the cytotoxicity of the TIL was compared with that for TIL from the same tumour after the lymphocytes had been washed a further 6 times in Medium 199. Three effector: target (E/T) ratios, 5:1, 10:1 and 20:1, were used. The proportion of effector populations showing cytotoxicity was 2/12 for unwashed TIL and 9/12 for washed TIL (P less than 0.006). At the 5:1 E/T ratio the level of cytotoxicity was not significantly greater for washed TIL, but at the 10:1 ratio washed TIL showed significantly more cytotoxicity (P less than 0.025. At the 20:1 E/T ratio, a comparison was possible in 15 cases and the washed TIL again showed greater cytotoxicity (P less than 0.001). Images Figure

Decreased membrane rigidity is one of the characteristics of malignant cells, resulting in part from the desaturation of stearic acid into oleic acid. In this study we investigated the influence of stearic acid on tumour cell inhibition in vitro and tumour development in vivo. Stearic acid inhibited the colony-forming ability of 4 out of 5 rat and two human tumour continuous cell lines in vitro. In contrast, the colony-forming ability of rat fibroblasts was not inhibited and that of human foetal lung fibroblasts was inhibited at a higher dose than that required to inhibit human tumour cell lines. Using a model of rat mammary carcinoma induced by nitroso-methyl urea (NMU) the subcutaneous injection of stearic acid at weekly intervals prevented tumour development in 5 to 10 rats. Using iodostearic acid twice weekly, 11 of 19 rats were alive and tumour free at week 22 whilst all of 14 animals injected with NMU alone had died of tumour by the 16th week. The ratio of stearic to oleic acids in erythrocyte membranes was significantly reduced in the tumour-bearing rats, but was normal in tumour-free animals treated with stearic or iodostearic acid. These preliminary data indicate that stearic acid inhibits tumour development in rats.