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PubMedDate not supplied

A formal model of family medicine.

BACKGROUND: The American Board of Family Practice is developing a computer-based recertification process. An optimal implementation requires a formal model of family medicine, which will become the basis for a knowledge base. DESIGN: The proposed model of family medicine contains six entities: Population, Record, Agents of Change, Health States, Findings, and Courses of Action. The model illustrates 15 important relations between entities. For instance: Health States Lead to Health States, and Findings Associate with Health States. These two relations describe natural history, manifestations of disease, and the effects of medical interventions and risk factors. Because time is such an important aspect of primary care, nearly all numeric data are represented as graphs of possible values over time, called Patterns, which include details about periodicity. Patterns and other aspects of the model provide a means of describing covariance between observations, such as the influence of height on weight. RESULTS: The model reflects many family practice activities and suggests some formal descriptions of family practice. For instance, diagnostic activities focus largely on classifying early or short segments of Patterns in Findings. Most medical interventions attempt to alter either the probability distributions in a Lead-to relation or the impact of a Finding. CONCLUSION: The proposed model of family medicine could find uses in many applications, including computer-based tests, medical records, reference systems, and decision support tools.

Family Practice↗
PubMed1992

Mathematical assessment of the spatial distribution of Langerhans cells in guinea pig epidermis.

Two mathematical indexes, Hopkins-Skellam index (HSI) and Morisita index (MI), were applied to assess the distribution of ATPase-stained epidermal Langerhans cells (ELC) in the guinea pig skin. To our knowledge, this is the first report in which the degree of regularity has been expressed numerically by computation based on theoretical equations. The regularity of ELC in the normal skin was confirmed by the value of HSI (P < 0.0001). In the topical steroid applied skin, the number of ELC decreased significantly but the value of HSI was similar to that of the normal skin; while in the ultraviolet B (UVB) exposed skin, both number of ELC and regularity of ELC distribution decreased significantly. The graph of MI for the UVB exposed skin clearly showed that the distribution of ELC had local clumps. The two indexes, HSI and MI have been quite useful for determining the regularity of ELC. These indexes may have a wide application to other cells.

Animals↗
PubMed1988

Biological applications of the SAS system: an overview.

The SAS system provides biologists with a flexible, easy to use software package for data analysis. Through a combination of data management tools, a wide variety of pre-programmed procedures for sorting, graphing, and statistical analysis and a sophisticated programming language, SAS software can perform all analytical needs for most problems. The recent availability of SAS software on mainframes other than IBM, and more recently on the microcomputer, means that most scientists can have access to the software. In this review we discuss the structure of the SAS language and demonstrate its power in the analysis of biological problems. Although to a lesser extent now than originally, the SAS system is statistically oriented and a working knowledge of statistics is recommended before using its statistical capabilities. However, all biologists will find its data management and summarization capabilities very useful.

Biology↗
PubMed1976

Clinical trials in surgery.

Scientific knowledge is reliable because it has been built on accurate measurements. Clinical knowledge is not. The science of biometry was started in 1835 by the Belgian astronomer Adolphe Quetelet. In the last fifty years a precise set of rules have been invented for this science. The method is suitable for a wide range of problems in clinical medicine and as the result of its application in recent years a firm foundation has been laid upon which scientific clinical knowledge can be built. Surge-ns, particularly, have been slow to apply biometrical methods to their clinical problems; but a start has now been made. The outcome of a particular type of treatment is determined by a complex set of inter-acting factors. The basis of the appropriate biometrical method is the elimination of all bias in favour of one of the rival techniques being compared. If this precaution is taken the observed results of the trial can be fitted onto Quetelet's distribution graph, and the probability of the observed difference in the results being due to chance, and nothing else, can be measured mathematically. The accuracy of this measurement deteriorates the greater are the number of the patients who can not be found and examined at the end of the trial. To make this point two trials conducted by the author are used. In the trial designed to discover if postoperative deep vein thrombosis and pulmonary embolism could be prevented by electrically stimulating the patients legs during the operation there was no difficulty. All the patients were examined at the end of the trial, because it ended before any of the patients left the hospital. The trial to discover if the primary treatment of varicose veins ought to be by Fegan's sclerotherapy or by operation was the exact opposite. At the end of the first year of the two year trial 15% of the patients could not be traced. The results in these patients, therefore, was unknown. Because of this, elaborate mathematical calculations had to be made to try and reach a reliable conclusion to the trial. The loss of patients before the end of the trial is a very serious practical difficulty which besets all long-term clinical trials.

Clinical Trials as Topic↗
PubMed1993

A hybrid system for diagnosing multiple disorders.

This paper investigates the advantages of introducing feedback between the processes of automated medical diagnosis and automated diagnostic-knowledge acquisition. Experimental results show that a diagnostic system with such feedback is capable of an efficiency/accuracy trade-off when applied to the problem of diagnosing multiple disorders. A primary feature of this work is a new mechanism, called the "diagnostic-unit" representation, for remembering results of previous diagnoses. The diagnostic-unit representation is explicitly tailored to capture the most likely relationships between disorders and clusters of findings. Unlike typical bipartite "If-Then" representations, the diagnostic-unit representation uses a general graph representation to efficiently represent complex causal relationships between disorders and clusters of findings. In addition to the basic diagnostic-unit concept, this paper presents experience-based strategies for incrementally deriving and updating diagnostic units and the various relationships between them. Techniques for selecting diagnostic units relevant to a given problem and then combining them to generate solutions are also described.

Artificial Intelligence↗
PubMedDate not supplied

[The effect of knowledge regarding the importance of oral health in pregnancy].

INTRODUCTION: Although in modern dental medicine a pregnant woman and her foetus are completely safe during all dental procedures, the prevention is still the most effective measure for the preservation of oral health in pregnancy. However, pregnant women often visit a stomatologist only when there are already serious disturbances, regardless of the fact that they are referred to a stomatologist even at their first visit to a gynaecologist. The aim of the study was to investigate (possible) changes in pregnant women's attitudes toward oral health during pregnancy according to our educational programme. METHODS: One hundred and sixty pregnant patients were randomly selected for the educational programme and were enrolled in the study. In direct contact (groups of 4 to 14 pregnant patients) they received basic information about the condition for attaining and maintaining their and foetal good health [1]. In order to establish the results, three anonymous questionnaires were conducted. Two of them made the questionnaire A because of identical results obtained before and after the education, and the third questionnaire B was different, and was conducted at the end. The questionnaire B concerned the personal point of view of pregnant women about the obtained information [2]. RESULTS: The results of the first two questionnaires (questionnaire A) are shown in Graph with a quantity of correct answers expressed in percents. The results of the questionnaire B are formulated according to answers to a question with "YES" and "NO", and they are expressed in percentage. The following results were obtained for questionnaire B: A hundred percent of pregnant women stated that they had learned something new about oral health, 67 percent had immediately changed their nutrition for healthy food, 100 percent of them understood well the significant role of fluor prophylaxis, 16 percent did not accept it for unknown reasons, but 100 percent thought that it was very useful to hear lectures about oral health [3]. DISCUSSION: A great interest existed for all preventive stomatologic measures and dental procedures during pregnancy, which formerly, as a rule, were avoided because of ignorance [4]. It is necessary to carry out a proper prevention, and adequately inform and motivate pregnant women, so that we could have a satisfied mother and carefree child in the future.

Attitude to Health↗
PubMedDate not supplied

[Perception of risk for infection with the human immunodeficiency virus].

Prevention of AIDS is very complex and requires, apart from basic knowledge about modes of transmission and protection, individual awareness of personal risk of infection and modification of one's risky behavior. Perception of risk has been suggested as an important element of sexual behavior change among people who engage in behaviors that place them at risk of HIV infection. This study investigates perceived risk of an HIV infection among inhabitants of municipality of Palilula. The purpose of this study was to determine the relative accuracy of risk assessment, especially for those with high-risk sexual behavior and to assess the factors related to self perception of developing AIDS. The survey was conducted as a household survey in Belgrade municipality "Palilula". The design of the survey was based on a two-stage stratified random sample. The population of Palilula municipality was divided in two stratums and 840 households were selected from each stratum. All members of selected households aged 15-49 years were interviewed. Total of 2659 persons was interviewed. Self administered questionnaire, developed by WHO and described in the Evaluation of National AIDS Programme: A Methods Package 1. Prevention of HIV infection, Geneva, 1994, was translated and adapted for local application. For analysis of findings methods of descriptive statistics, chi square test and logistic regression were used. Statistical analysis was performed using SPSS/PC. The results showed that most of the respondents (1662, 62.5%) do not perceive themselves to be at risk of HIV infection. Interestingly, almost one quarter of the sample couldn't estimate personal chances of being HIV infected. Significantly larger proportion of respondents living in urban area than those living in rural area perceived themselves at risk (17.1% of urban vs. 7.7% from rural area, chi square = 54.06, Ir0.00). Significant differences between age groups were found for perception of personal risk. Respondents up to 19 and those older than 25 in more than 60 percent and only a half of those between 20 and 24 believed that there was no chance they could become HIV infected. Almost 16% of respondents between 20 and 24 believed that they had some chances of contracting HIV, also approximately one third of them couldn't estimate personal risk of contracting HIV infection (chi square = 2.10, p = 0.00)(Graphe 1). Those who engaged in sex with irregular partners were found to perceive themselves in higher risk then those who were engaged in sex only with regular partners in previous 12 months. One fifth of those with irregular partners estimated their chances as good versus only 10% of those with only regular partners. A logistic regression analysis found that those who believed they were personally at risk knew someone with HIV, had more irregular sexual partners in last 12 months, were younger, and lived in urban area (Table 1). People correctly perceived the risk of HIV infection as being minimal as most of them didn't engage in risk behavior. Risk perception was higher among those who had more irregular partners, younger and those from urban area. Most important predictor of risk perception was knowledge of HIV positive individual.

Adolescent↗
PubMed1986

The biomechanics of the long jump.

The preceding review has been based on over 200 publications in Czech, English, French, German, Japanese, Polish, and Russian. Even a cursory perusal of these materials is sufficient to show that much has been done to try and obtain a scientific understanding of long jump techniques. It is clear, too, that still more remains to be done. Much of the work to date has been focused on just a few aspects of long jump technique. Other important aspects have received relatively little attention. The latter include the accuracy of the approach, the techniques used during the final strides of the approach, the role of elastic energy in the takeoff, the initiation and control of the jumper's angular momentum, and the techniques used in the landing. Future research efforts might well be directed towards resolving major issues concerning these aspects of long jump technique. The methods used to gather data in the studies reviewed have been rather unimaginative. Two-dimensional cinematography has been used in the vast majority of the studies and force platforms in a few. Other data-gathering procedures like three-dimensional cinematography, electromyography and accelerometry have rarely, if ever, been used. In only one or two studies was anything remotely approaching experimental or technological innovation in evidence. The methods used to analyze data have also been very limited. With the notable exception of a study by Ballreich, few papers have involved anything more sophisticated than means, standard deviations, correlation coefficients and an occasional multiple regression equation. Given these facts, it is hard to avoid the conclusion that our knowledge of long jump techniques might be greatly improved if the full range of available and appropriate procedures were turned to the purpose. Finally, no review of the literature on long jump techniques would be complete without reference to the level of scholarship displayed in the works under consideration. With only a few exceptions, the level shown in the scientific papers reviewed here left much to be desired. Time and again, variables were not defined, crucial measurement techniques were not described and major results were not presented or discussed. In addition, much of the data presented in tables and graphs were patently in error. In light of all this, it is clear that unless the level of scholarship improves, future progress in this area of sports biomechanics is likely to be very slow.

Biomechanical Phenomena↗
PubMed1981

Systematic method of development in liquid chromatography applied to the determination of antiepileptic drugs.

The object of a liquid-chromatographic analysis is to separate, identify, and quantitate the constituents of interest in a sample mixture within an acceptable analysis time. This will be achieved by a systematic analysis development rather than by a trial-and-error approach. Such a systematic procedure requires a knowledge of the chromatographic parameters governing resolution and analysis time and their relative influences on resolution and its experimental implication. Furthermore, basic information about the mechanisms of the modes of liquid chromatography (adsorption, partition, ion exchange, and steric exclusion) and about the types of sample which can be preferentially analyzed by them is necessary. This information leads to a rational selection of the separation system that promises the best chance of success. In the subsequent experimental work, the analyst systematically measures and calculates resolution and analysis time as functions of selectivity, capacity, and efficiency of the phase system under selected chromatographic conditions. The essential chromatograms, tables, and graphs resulting from this systematic method of development are documented so that it is possible to replicate the analysis procedure in the laboratories involved. The result is a set of chromatographic conditions capable of achieving an optimum compromise between resolution and analysis time. The procedure is applied to routine therapeutic drug monitoring of antiepileptic drugs in patient serum.

Anticonvulsants↗
PubMed1995

Representing clinical narratives using conceptual graphs.

The analysis of medical narratives and the generation of natural language expressions are strongly dependent on the existence of an adequate representation language. Such a language has to be expressive enough in order to handle the complexity of human reasoning in the domain. Sowa's Conceptual Graphs (CG) are an answer, and this paper presents a multilingual implementation, using French, English and German. Current developments demonstrate the feasibility of an approach to natural Language Understanding where semantic aspects are dominant, in contrast to syntax driven methods. The basic idea is to aggregate blocks of words according to semantic compatibility rules, following a method called Proximity Processing. The CG representation is gradually built, starting from single words in a semantic lexicon, to finally give a complete representation of the sentence under the form of a single CG. The process is dependent on specific rules of the medical domain, and for this reason is largely controlled by the declarative knowledge of the medical Linguistic Knowledge Base.

Artificial Intelligence↗
PubMed1990

Isotachophoretic separation of organic acids in biological fluids.

The operating conditions for the isotachophoretic separation of organic acids were evaluated. At pH values ranging from 2.90 to 4.25 both relative step heights and molar flow-rates were determined experimentally for 26 anions. Comparing the observed values with simulated data, highly significant (p = 0.0001) correlation coefficients of 0.993 and 0.920, respectively, were found at pH 3.50. Whereas the concentration of the leading electrolyte did not affect the relative step heights, it increased the molar flow-rates significantly. The same applied to the detection current. The time of analysis was observed to be a function of the concentration of the leading electrolyte. However, the time elapsed between injection of the analyte and its detection depended solely on the volume and not on the amount of analyte injected. In isotachophoresis, incomplete separation of two compounds is indicated by the occurrence of a mixed zone which can hardly be distinguished from a pure zone. Thus, knowledge of the separation capacity is a prime prerequisite in optimizing the system for the analysis of biological fluids. The separability of nine equimolar pairs of anions was determined at pH values ranging from 2.90 to 4.25. Although two ionogenic constituents would separate only when their migration rates in the mixed state were different, no clear correlation was observed between separation capacity and difference in relative mobility. Separability, however, was found to increase with increasing concentration of the leading electrolyte. While the separation capacity was not influenced by the electric current, it was significantly affected by the volume injected. In subsequent analyses of serum, cerebrospinal fluid, seminal plasma and prostatic fluid, a variety of organic acids could be detected. Calibration graphs for the detected anions revealed a detection limit of 1 nmol and linearity over their biological concentration ranges. Further, the isotachophoretic results correlated well with high-performance liquid chromatographic and enzymatic analyses of citric acid and lactic acid in human seminal plasma and cerebrospinal fluid, respectively.

Acids↗
PubMed1990

Adding meaning to a design copy task through representational stimuli.

Occupational therapists frequently use their knowledge of occupation to add meaning and purpose to therapeutic tasks. This study investigated the effects of an attempt to add meaning to a particular occupational situation--a design copy task. Added meaning was given to the design copy task through the use of stimulus figures that were representational of familiar objects--an arrow, a house, and a face. The control condition consisted of three nonrepresentational figures composed of the same geometric shapes, in the same locations on the paper as the representational figures, but combined differently. The order of presentation was controlled for. The study used 30 elderly subjects (22 women and 8 men) from six nursing homes. The accuracy of the drawings was measured by a blind rater using graph overlays and predetermined rules of scoring. A two-way analysis of variance with one repeated measure (Order X Type of Figure) indicated significant differences at the .01 level between the representational and nonrepresentational figures. This study demonstrates how added meaning can enhance performance on a visuomotor task in a vulnerable population.

Aged↗
PubMed1994

Affiliations among steroid receptors as revealed by multivariate analysis of steroid binding data.

To illustrate the informative value of descriptive multivariate analysis in biochemical screening, we have analyzed several data matrices relating to the binding of steroids to the estrogen, progestin, androgen, glucocorticoid and mineralocorticoid receptors in different organs and species. We first compared dendrograms of steroid hormone receptors, that were obtained by an automatic hierarchical classification analysis of the binding data, to published phylogenetic trees of nuclear receptors based on amino-acid sequence analysis. The former classification describes the affiliations among the receptors as given by the binding specificity of a population of 187 steroids in a traditional cytosol binding assay (an indirect comparison of ligand binding sites); the latter describes the affiliations among the receptors as given by a comparison of selected primary sequences involved in ligand-dependent regulation of transactivation and dimerization. A similar hierarchical classification was also performed on the binding data of 62 steroids to myometrium cytosol from different species in order to show to what extent the progesterone-binding proteins in these species are affiliated. Hierarchical clustering methods classify each type of variable (receptor or steroid) independently. In order to be able to correlate both types of variable (receptors and steroids) on single-display graphs, it is necessary to resort to correspondence factorial analysis (CFA). CFA ranks the information content within the experimental system, highlighting major correlations and disclosing secondary correlations by eliminating redundant information and background noise. This multivariate method, applied to the analysis of published data, illustrated the particular specificity of estrogen binding in human vagina and raised the question of the nature of the binding protein in this tissue. Our examples are based on small data tables that can and have been analyzed de visu. However, it is certain that such descriptive multivariate techniques are indispensable for the analysis of large data banks not only to define structure-activity relationships but to estimate the degrees of affiliation among the biological variables being measured. Knowledge of such affiliations will help to organize available information in a context where the complexity of the biological systems under study is becoming increasingly apparent.

Animals↗
PubMed1995

Associating semantic grammars with the SNOMED: processing medical language and representing clinical facts into a language-independent frame.

We describe one approach for natural language processing of medical texts that associates a semantic grammar with the SNOMED (Systematized Nomenclature of Medicine). Our research hypothesis is that the combination of the nomenclature's declarative knowledge with a formal grammar would create a scientific sublanguage embedded with medical knowledge that could be used for analyzing and formatting medical texts. This combination permitted the abstraction of templates we call "semantic patterns." These patterns represent both linguistic and medical knowledge, packed into a hybrid information format. We analyzed manually case reports described in the New England Journal of Medicine (NEJM) from 1985 to 1988 and extracted empirically a semantic grammar. Over 2,000 sentences were analyzed. About 160 structural semantic patterns were abstracted and included in the database of one parser. We tested the parser using reports from 1989 to 1990. Results show that this approach is efficient for processing, indexing, and structuring diverse parts of case reports narrative. The analyzed medical sentences are structured into a language-independent semantic frame format. We conclude that the association of semantic grammars with the SNOMED enabled the construction of a formal system for analysis and representation of clinical facts. The transformation of the structured information from its frame format into other representational schemes, like conceptual graphs, is straightforward. Another application includes the use of the formatted language-independent frame for telegraphic English-Japanese translations of medical sentences.

Language↗
PubMedDate not supplied

Topological shape and size of peptides: identification of potential allele specific helper T cell antigenic sites.

A database of primary sequences of 28 immunogenic peptides, known to elicit T cell response, derived from five different haplotypes was compiled to identify allele specific helper T cell antigenic sites using a rule based graph-theoretical method. The prediction was based on the identification of allele specific patterns in the form of "topological shape and size" present in the peptides. Indices computed from weighted connected graph models of amino acid side chains and peptides were used in this purpose. The system was trained by 10 Ad and 10 non-Ad restricted peptide sequences, assigned actives and inactives, respectively, chosen randomly from the database, and four Ad and four non-Ad restricted sequences were kept as test peptides. This allowed the system to learn about "topological shape and size" specific for Ad restricted peptides from the differences, if any, they had with the inactive peptides in that respect. The system made 100% correct prediction for the training set peptides and misclassified only one inactive peptide of the test set. The system also identified crucial residues for lambda repressor 12-24 and insulin A-chains. This identification also shows that activity related/crucial residues could be located at varying distances from the peptide terminals. To our knowledge, the method is unique of its kind in the literature and may find application in the rational design of synthetic vaccines and other peptides of immunological importance.

Alleles↗
PubMed1991

Thought police. Healthcare executives must carefully guard intellectual property developed in their facilities.

Healthcare executives should have a working knowledge of intellectual property law--the legal principle that, for a limited period, treats intangible ideas and concepts as if they were products or property. Not only should administrators be aware of how to protect their facilities' patents, trademarks, copyrights, and trade secrets, but they must also be sure that employees in their own facilities do not infringe on the intellectual property of others. A patent is granted when an inventor proposes a useful new process, machine, "article of manufacture," or composition of matter, including any new and useful improvement on existing items in these same categories. A trademark is a name, symbol, device, or combination thereof adopted and used by an institution to identify its goods or services and to distinguish them from its competitors' goods or services. Expressions of ideas and thoughts set forth in words, sentences, paragraphs, sketches, pictures, graphs, or any other means of conveying ideas or concepts commonly understood to be works of authorship--both published and unpublished--may be protected by a copyright. Trade secret law applies to those who might misappropriate information that has been given to them because of their special relationship with the holder of the trade secret (i.e., through employment, contract, or other fiduciary or trust relationship).

Confidentiality↗
PubMed1995

"Hyperstat": an educational and working tool in epidemiology.

The work of a researcher in epidemiology is based on studying literature, planning studies, gathering data, analyzing data and writing results. Therefore he has need for performing, more or less, simple calculations, the need for consulting or quoting literature, the need for consulting textbooks about certain issues or procedures, and the need for looking at a specific formula. There are no programs conceived as a workstation to assist the different aspects of researcher work in an integrated fashion. A hypertextual system was developed which supports different stages of the epidemiologist's work. It combines database management, statistical analysis or planning, and literature searches. The software was developed on Apple Macintosh by using Hypercard 2.1 as a database and HyperTalk as a programming language. The program is structured in 7 "stacks" or files: Procedures; Statistical Tables; Graphs; References; Text; Formulas; Help. Each stack has its own management system with an automated Table of Contents. Stacks contain "cards" which make up the databases and carry executable programs. The programs are of four kinds: association; statistical procedure; formatting (input/output); database management. The system performs general statistical procedures, procedures applicable to epidemiological studies only (follow-up and case-control), and procedures for clinical trials. All commands are given by clicking the mouse on self-explanatory "buttons". In order to perform calculations, the user only needs to enter the data into the appropriate cells and then click on the selected procedure's button. The system has a hypertextual structure. The user can go from a procedure to other cards following the preferred order of succession and according to built-in associations. The user can access different levels of knowledge or information from any stack he is consulting or operating. From every card, the user can go to a selected procedure to perform statistical calculations, to the reference database management system, to the textbook in which all procedures and issues are discussed in detail, to the database of statistical formulas with automated table of contents, to statistical tables with automated table of contents, or to the help module. he program has a very user-friendly interface and leaves the user free to use the same format he would use on paper. The interface does not require special skills. It reflects the Macintosh philosophy of using windows, buttons and mouse. This allows the user to perform complicated calculations without losing the "feel" of data, weight alternatives, and simulations. This program shares many features in common with hypertexts. It has an underlying network database where the nodes consist of text, graphics, executable procedures, and combinations of these; the nodes in the database correspond to windows on the screen; the links between the nodes in the database are visible as "active" text or icons in the windows; the text is read by following links and opening new windows. The program is especially useful as an educational tool, directed to medical and epidemiology students. The combination of computing capabilities with a textbook and databases of formulas and literature references, makes the program versatile and attractive as a learning tool. The program is also helpful in the work done at the desk, where the researcher examines results, consults literature, explores different analytic approaches, plans new studies, or writes grant proposals or scientific articles.

Computer-Assisted Instruction↗
PubMed1993

Can nutrition information increase sales of healthful vended snacks?

Snack selections from unrefrigerated vending machines were studied in relation to increasing availability of nutrient-dense snack options and providing nutrient information at four selected vending sites on a large university campus. Only four of 133 different snacks available for unrefrigerated vending met the criterion for nutrient-dense snacks. When snack proportion was changed to increase availability of nutrient-dense snacks, sales dropped. When nutrition information in bar graph form was posted on the machines, sales increased but not back to the original level. Although snack sales increased after graphic nutrition information was posted, sales were primarily for the least nutrient-dense, perhaps because few well-liked, nutrient-dense snacks were available for unrefrigerated vending. Schools concerned about providing a selection of vended snacks in agreement with the U.S. Dietary Guidelines might be advised to maintain refrigerated vending or to pursue a "healthy snack" machine concept.

Adolescent↗