Literatura científica selecionada sobre o tema "Substance experimentation"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Consulte a lista de atuais artigos, livros, teses, anais de congressos e outras fontes científicas relevantes para o tema "Substance experimentation".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Artigos de revistas sobre o assunto "Substance experimentation"
1
Wadsworth, S. J., R. P. Corley, J. C. DeFries, D. W. Fulker, Gregory Carey e R. Plomin. "Substance experimentation in the Colorado Adoption Project". Personality and Individual Differences 23, n.º 3 (setembro de 1997): 463–71. http://dx.doi.org/10.1016/s0191-8869(97)80012-8.
Texto completo da fonte
2
Lobo, Dr Loveena, e Ms Amlin Roche. "Exploring Substance Use Among Late Adolescents in Mangaluru, India". International Journal of Advanced Medical Sciences and Technology 3, n.º 5 (30 de agosto de 2023): 1–10. http://dx.doi.org/10.54105/ijamst.d3039.083523.
Texto completo da fonteResumo:
Adolescence is a significant transitioning phase of life where the young are prone to experiment and engage in risk-taking behaviours such as Substances use. The study objectives were to ascertain the reasons for first-time use of substances, occasions of use, and the sources of availing of banned substances among late adolescents. A quantitative and qualitative study approach was adopted with an exploratory and descriptive research design. Around 532 late adolescent students participated in the study, from colleges in urban & rural areas. The study outcomes highlight the primary reasons for adolescent substances-use was party/fun (45%) followed by curiosity&experimentation (35%) and suggestion from friends & family (11%). The top three occasions for substance use are parties (53%), weekends (18%) and when studying (10%). The top three sources of availing of banned substances are friends/ college mates (18%), agents (12%), and petty shops (8%). Qualitative findings showed that the first-time use of addictive substances among adolescents is primarily due to curiosity, experimentation and the influence of friends. Interviews revealed that faulty parenting techniques such as poor communication, providing ample finances and lack of supervision of hostellers are the common markers of adolescent substance use. Hostels and parties are often popular places among students to initiate substance use. The channels for obtaining Banned substances are through students (for financial gains) who have dealt with middlemen/traffickers in the past. Often vehicles such as cars/trains and modern technology are adopted by drug traffickers. Instances of Weed (marijuana) being grown at home in the backyards is seen. Various recommendations at Educational Institutes, law enforcement and Government Policy levels are made. Further research, to probe deeper into understanding the effects of substance use and health concerns due to substance use is suggested.
3
Grady, Katherine, Kelin E. Gersick, David L. Snow e Marion Kessen. "The Emergence of Adolescent Substance Use". Journal of Drug Education 16, n.º 3 (setembro de 1986): 203–20. http://dx.doi.org/10.2190/elar-n5pw-bh6a-vd39.
Texto completo da fonteResumo:
This longitudinal study examines patterns of emerging substance use among sixth, seventh, and eighth grade students in two New England towns. The results show substantial levels of experimentation and use extending down to the sixth grade and variations in use level depending on the students' community, sex, race, and parents' marital status. This study also examines rates at which students were offered various substances and, by comparing use and offer rates, charts rejection/acceptance rates for the gateway substances across the three grades. The findings suggest the notion of critical periods for substance use initiation and underscore the importance of understanding these early use patterns as the first step in the design and implementation of primary prevention programs.
4
Knopf, Alison. "Screen time associated with substance use in young adolescents". Alcoholism & Drug Abuse Weekly 36, n.º 46 (6 de dezembro de 2024): 6. https://doi.org/10.1002/adaw.34344.
Texto completo da fonteResumo:
Researchers have found that screen tie was associated with alcohol, nicotine, and cannabis experimentation in young teens. With each additional hour spent on social media, texting, and video chatting, the odds of any substance experimentation went up. The study, “Prospective association between screen use modalities and substance use experimentation in early adolescents” by Jason M. Nagata M.D. is published in the January 2025 issue of Drug and Alcohol Dependence. The researchers based their information on data from the Adolescent Brain Cognitive Development (ABCD) study of the National Institutes of Health, which funded the study.
5
N.Abhijit e M.Pradeep Kumar. "A Cross Sectional Study on Prevalence and Determinants of Substance Abuse among College Students". Indian Journal of Public Health Research & Development 15, n.º 3 (4 de julho de 2024): 299–305. http://dx.doi.org/10.37506/p3tt9093.
Texto completo da fonteResumo:
Background: Substance abuse in India continues to be a major problem for both individuals and society. Substance abuse refers to hazardous use of psychoactive substances, including smoking, alcohol and illicit drugs. Substance abuse can lead to dependence syndrome-a cluster of behavioral, cognitive and physiological phenomena that develop after repeated use of substances like alcohol and tobacco. Objectives: To find out the prevalence and determinants of substance abuse among college students and assess the awareness regarding treatment of substance abuse among them. Methodology: A cross sectional study was conducted among 200 college students randomly selected from different colleges in Ongole from April to May 2022. Data was collected by using pre-tested semi structured questionnaires after taking informed consent from study participants. p- value of less than 0.05 was considered statistically significant. Results: Prevalence of substance abuse was 34%, and the common substances abused were alcohol, smoking, ganja and gutka. Major determinants were experimentation followed by peer pressure and family influence. Hostel stay, socio economic status and professional courses are found to be statistically significant for substance abuse . Conclusions: Substance abuse is a rampant problem globally. Proper awareness has to be provided regarding substance abuse to children by family and teachers right from a young age to prevent increased incidence of substance abuse.
6
Emboden, William A. "“Natural Highs” in an Historical and Biological Context". Journal of Drug Education 18, n.º 1 (março de 1988): 33–47. http://dx.doi.org/10.2190/gq0b-4cbx-bb15-m6lh.
Texto completo da fonteResumo:
Historical and contemporary patterns of substance use and abuse are recognized, and the error in believing psychoactive natural substances to be reasonably safe is pointed out. The plethora of literature on drug-induced ecstasies among diverse peoples produces over-confidence in the safety of inducing altered states by means of natural chemicals. Given the current level of experimentation, the lack of a context for use, and the lack of knowledge of the toxicity of many plant sources presents a very real problem. Documented evidence of recent changes in patterns of experimentation with diverse drugs, many from natural sources, suggests that the naive user may experience an unwarranted level of confidence. Diverse genera and species of plants that produce psychoactive effects are presented. Many of these are now in use and others will undoubtedly be the subject of uncontrolled experimentation in the future. Educators, researchers, legislators, physicians, and therapists should be aware of chemicals from natural sources, and the categories of experience that they provoke.
7
Mills, Laura, Alexandre Dionne, Jennifer Bingley e Shelley Watson. "Stumbling Along, Walking on Eggshells and Vicious Circles: What Happens while Families Wait for Youth Substance Use Treatment". Canadian Journal of Family and Youth / Le Journal Canadien de Famille et de la Jeunesse 11, n.º 1 (23 de janeiro de 2019): 56. http://dx.doi.org/10.29173/cjfy29455.
Texto completo da fonteResumo:
Youth substance use is a serious problem that has immediate and long-term impact on individuals, families, and society. Adolescent substance experimentation that develops into abuse foreshadows long-term problems, such as adult addiction, co-occurring mental illness, declined or abandoned academic careers, and other individual and interpersonal harms. Early and effective intervention can mitigate the harmful effects on the lives of young people, their families, and their communities. Intervention may not be accessible, however, for adolescents and/or their families when they seek help, and wait lists are common. Waiting for treatment for substance use is the focus of this study, and in particular, the experience of waiting and its associated impacts on the youth’s substance use, involvement with police, running away, mental health and on the family unit. 118 parents of youth who use substances participated in a mixed methods study at Pine River Institute, a long-term residential youth treatment center. Clinical implications are discussed.
8
Raj V Soni. "CONSEQUENCES OF A SUBSTANCE ABUSE EDUCATION PROGRAM ON STUDENTS". IAAR Journal of Education - ISSN: 2583-6846 Peer-Reviewed Journal 4, n.º 2 (10 de dezembro de 2022): 13–23. http://dx.doi.org/10.58213/education.v4i2.46.
Texto completo da fonteResumo:
A person's physical growth has stopped throughout adolescence, and they are making the transition from childhood to adulthood. According to WHO, "the age between 10 and 19 years is a unique phase of life," during which a child experiences significant physical, emotional, and social changes. Adolescent substance abuse frequently starts at this phase of self-discovery and experimentation. Substance abuse among teens is uncommon. The most often utilized substances are tobacco, alcohol, and smoking. According to the "Global Youth Tobacco Survey," India consumes tobacco smokeless to a degree of 30 to 40 percent. With a 4.2% national prevalence, student use of smokeless tobacco ranges from 6% in Goa to 68% in Bihar. 13.6 percent of people currently use cigarettes and other tobacco products. According to research by the WHO, drinking and smoking account for 4% of the total global burden of disease (2000). The purpose of this study is to evaluate high school students' knowledge of substance abuse.
9
Basnet, Puspa, Reshu Agrawal Sagtani e Shital Bhandary. "Factors Affecting Psychoactive Substances Use Among Bachelor Level Students of Nepalgunj SubMetropolitan City". Journal of Nepal Health Research Council 19, n.º 2 (6 de setembro de 2021): 288–94. http://dx.doi.org/10.33314/jnhrc.v19i2.3431.
Texto completo da fonteResumo:
Background: Psychoactive substance use among Bachelor level students have different risk and protective biological, intrapersonal, interpersonal, and sociocultural factors. This study was conducted with the aim to explore the factors affecting psychoactive substance use among Bachelor level students of Nepalgunj sub-metropolitan city.Methods: A qualitative cross-sectional study was conducted among Bachelor level students from different streams of Nepalgunj sub-metropolitan city. Pre-validated Interview Guidelines was used for 13 In-depth Interviews with Bachelor level students from different streams using psychoactive substances and 12 Key Informant Interviews with parents/guardians and teachers of some of the selected students. Deductive thematic analysis based on Domain model was done to explore the risk and protective factors for psychoactive substance use.Results: The study identified different risk and protective factors affecting psychoactive substance use within each biological, intrapersonal, interpersonal, and sociocultural domain. Major risk factors identified were adolescence and teenage, male sex, curiosity and experimentation, use for fun, to relieve or cope stress/tension, inadequate awareness, peer influence and pressure, use of psychoactive substances in family, availability, advertisements, social acceptance, and lack of strict rules and regulations. Major protective factors identified were adequate awareness, negative perception, self-motivation, lack of free time/leisure, mentality/state of mind, personal responsibilities, guidance from family, negative perception of society, and reputation.Conclusions: Increasing awareness, developing positive attitudes, reducing social acceptance, and implementation of strict rules and regulations may help minimize and/or eliminate psychoactive substance use by Bachelor level students.Keywords: Acceptance; bachelor level students; curiosity; protective factors; psychoactive substance use; risk factors
10
Green, ReJoyce, Anna E. Kirkland, Brittney D. Browning, Brittany E. Bryant, Alexis M. Garcia, Rachel L. Tomko, Kevin M. Gray et al. "325 Predictors of Substance Use Initiation by Late Childhood: Findings from the Adolescent Brain Cognitive Development (ABCD) Study". Journal of Clinical and Translational Science 7, s1 (abril de 2023): 97. http://dx.doi.org/10.1017/cts.2023.374.
Texto completo da fonteResumo:
OBJECTIVES/GOALS: Adolescence represents a critical period for substance use initiation. Various factors may contribute to trying a sip or single puff of a substance, that could lead to more frequent use. However, less is known about how predictors from multiple domains converge to impact risk for general substance use initiation. METHODS/STUDY POPULATION: The Adolescent Brain Cognitive Development (ABCD) study is a multi-site longitudinal study following youth into early adulthood. The present study included 7,644 ABCD children who reported no lifetime substance use (including any experimentation) at baseline (ages 9–10). Our primary aim was to use a random forest classification model to predict binary substance use initiation, defined as trying any non-prescribed substance (e.g., alcohol, tobacco, cannabis, non-prescribed medications), during a 2-year follow-up after baseline. A total of 402 variables from the following categories were examined as predictors: demographics, peer substance use and availability, mental and physical health, culture and environment, biospecimens, neurocognitive functioning, and structural neuroimaging variables. RESULTS/ANTICIPATED RESULTS: Over a two-year follow-up, 751 (9.8%) of substance-naïve children reported trying a substance by age 11. The most common substance was alcohol, followed by cannabis and tobacco. Mean Decrease Accuracy (MDA) values were used to assess the relative importance of each predictor. The overall accuracy of the model in accurately predicting group membership (no substance use initiation vs. substance use initiation) was 57.66%. Of the top 5 predictors, the most important predictor was intent to use alcohol (MDA = .002). The following top predictors were structural neuroimaging variables: volume and surface area of right lateral occipital lobe (MDA = .0009 and .0008, respectively), surface area of right inferior temporal lobe (MDA = .0007), and surface area of left superior frontal lobe (MDA = .0007). DISCUSSION/SIGNIFICANCE: A combination of intent to use alcohol and structural neuroimaging indices were among the top predictors of substance use initiation. Understanding predictors of early substance use experimentation is important for identifying at-risk youth that may require targeted intervention approaches.
Teses / dissertações sobre o assunto "Substance experimentation"
1
Washkansky, Gail. "Participants' perceptions of a high school substance use prevention programme". Thesis, University of the Western Cape, 2001. http://hdl.handle.net/11394/4595.
Texto completo da fonteResumo:
Magister Psychologiae - MPsychThere are many theories as to why adolescents engage in substance abuse. These theories have formed the basis of various substance abuse prevention programmes aimed at reducing this problem. Evaluation of these interventions is needed in order to assess their effectiveness and to improve on future prevention strategies. The literature highlights tensions and differences between the primary preventative approaches to substance abuse and the harm reduction model. It also suggests that psychosocial or life skills programmes and interventions employing a harm reduction approach tend to be viewed as more suitable for adolescents than other approaches. This study focuses on a high school intervention programme running since 1996, which has not yet been evaluated. It aimed to identify the programme's strengths and weaknesses, as well as participants' perception of the intervention. A qualitative research method was used, employing focus groups as the tool for data gathering. The sample for the study was made up of 30 volunteers from three grade 10 classes that completed the programme two years prior to this study. Data was transcribed verbatim and analyzed using thematic analysis. Links were made to the two approaches referred to above. Analysis of the data indicated that although stories used to warn and frighten people were shown to have a shocking impact on the participants, pupils found it difficult to make the connection between the speakers' horrific stories and their own experimentation with drugs and alcohol. It was found that participants appreciated the fact that they were being informed about the dangers of substance use, and that they were encouraged to take responsibility for their own decisions regarding this behaviour. The informal, non-judgemental stance of the speakers served to reinforce this message. In conclusion, the study indicated that the different methods used in the various prevention programmes are in fact not altogether different. It is suggested that the various models are potentially compatible, and can perhaps work together to establish an effective preventative strategy.
2
Shamgochian, Maureen. "The Stimulation of Luteinizing Hormone Secretion from Anterior Pituitary Cells in Culture by Substance P: A Dissertation". eScholarship@UMMS, 1990. https://escholarship.umassmed.edu/gsbs_diss/129.
Texto completo da fonteResumo:
The observations that substance P (SP) is localized in the anterior pituitary gland (AP) and is regulated by the hormonal status of the animal, as well as the demonstration of SP binding sites in the AP, have led to the idea that SP may participate in the regulation of AP function. Numerous and sometimes contradictory reports of SP effects on AP hormone secretion, particularly on luteinizing hormone (LH), left the question of whether SP acts directly at the level of the AP to regulate LH secretion still unanswered. To investigate a possible physiological function of SP in the AP, the effects of exogenous SP on LH secretion from AP cells from adult and prepubertal male and female rats in short term culture were studied. It was found that SP (100nM-1μM) significantly stimulates LH release in cultured AP cells and that this effect varies as a function of age and sex. SP has no significant effect on LH release from AP cells of male and female prepubertal rats. After day 30 a sharp increase in the response to SP occurs in both sexes. This level of responsiveness continues through adulthood in AP cells from the female rat. In contrast, AP cells from male rats failed to respond during adulthood (over 50 days of age) but were highly responsive during the peripubertal period (30-35 days). The possibility that the responsiveness to SP is influenced by the endocrine status of the animal was investigated by exposing AP cells from responding animals to androgens in vivo and in vitro. It was found that AP cells from female rats treated with androgen were less responsive to 100nM SP but did respond at higher doses of SP. SP effects on AP function were further analyzed in experiments using radioligand binding assays to assess possible changes in SP receptor number or affinity as related to age and sex. In AP membranes from female rats, maximum binding is 8-fold higher (Bmax=4.2 pmo1/mg membrane protein) than in AP membranes from male rats (Bmax=560fmo1/ mg membrane protein). These studies suggest a role for SP as a secondary regulator of LH secretion with possible physiological significance for reproductive function.
3
Zhang, Ting. "DEVELOPMENT AND PRECLINICAL EVALUATION OF LONG-LASTING COCAINE HYDROLASES FOR COCAINE OVERDOSE AND COCAINE USE DISORDER TREATMENT". UKnowledge, 2018. https://uknowledge.uky.edu/pharmacy_etds/93.
Texto completo da fonteResumo:
Cocaine is a plant-based illicit drug commonly involved in substance use disorder. Although cocaine overdose and cocaine use disorders cause adverse health consequences to individuals and the economic burden on their family and society, there are no FDA (Food and Drug Administration) approved medications for treatment. Recently, it has been recognized that delivery of cocaine hydrolase (CocH) is a promising therapeutic strategy. Human butyrylcholinesterase (hBChE), the primary enzyme involved in cocaine metabolism in human, have advantages over other candidates for the development of CocH. Previous studies in our laboratory have designed and characterized hBChE mutants that have ~4,000-fold improved catalytic efficiency against naturally occurring (-)-cocaine as compared to the wild-type hBChE. Besides the catalytic efficiency, the biological half-life is another essential factor that influences the desired therapeutic value in the long-term treatment of cocaine use disorder. In order to provide prolonged effects to reduce administration frequency in clinical use, efforts have been made to increase the retention time of CocHs in blood circulation by fusing CocHs with other thermostable proteins or their mutants, including human serum albumin (Albu) or the Fc region of the human IgG (Fc).
In this dissertation, we demonstrated the clinical potential and the benefits of long-lasting CocHs for cocaine overdose treatment. We used rodent models to show the ability of AlbuCocH1 to block or reverse manifestations of toxic effects of cocaine. In addition, a concomitant LC-MS/MS-based analysis was conducted to investigate the pharmacokinetic profile of a lethal dose of cocaine with the presence of AlbuCocH1. These experimental data demonstrated AlbuCocH1 as an effective cocaine detoxification agent by accelerating the metabolism of cocaine.
In order to examine the potential therapeutic value of Fc-fused CocHs in the treatment of cocaine use disorder, we conducted a series of behavioral experiments in rats to evaluate the effectiveness and duration of Fc-fused CocHs in blocking or attenuating cocaine-induced psychostimulant and discriminative stimulus effects. In addition, the intravenous self-administration model was used to investigate the long-term effectiveness of Fc-fused CocHs in blocking or attenuating the reinforcing effects of cocaine. It has been shown that a single dose of E30-6-Fc (3 mg/kg) was able to effectively alter the cocaine dose-response curve and attenuate the reinforcing efficacy of cocaine for at least a month in both male and female rats.
In summary, AlbuCocH1 (TV-1380), which failed to meet the primary efficacy endpoint in clinical trials for facilitating abstinence in cocaine-dependent subjects with a weekly dosing schedule (due to the short biological half-life), is more suitable to be developed as a cocaine detoxification agent. On the contrary, the newly designed Fc-fused CocH (e.g. CocH3-Fc, E30-6-Fc) with higher catalytic efficiency and longer biological half-life will be beneficial for long-term abstinence management in cocaine-dependent individuals.
4
Janota, Mathilde. "Premiers usages d’alcool, de tabac, de cigarette électronique et de cannabis : enjeux liés à l’utilisation des réseaux sociaux chez les collégiens et aux relations romantiques chez les étudiants". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0281.
Texto completo da fonteResumo:
L’alcool, le tabac, le cannabis et plus récemment la cigarette électronique figurent parmi les substances psychoactives les plus consommées en France. Les premières expérimentations surviennent majoritairement tôt, dès le début du collège, puis augmentent jusqu’au début de l’âge adulte. Cependant, la précocité de la première consommation est associée à un risque accru de développer des troubles de l’usage entraînant des conséquences négatives élevées tant sur la personne que sur son fonctionnement quotidien. Ces conséquences s’expriment également à partir de niveaux de consommation inférieurs, et impactent différentes sphères de la vie, incluant les relations interpersonnelles. Ces relations sont particulièrement importantes durant la période de l’émergence de l’âge adulte, également marquée par une augmentation des consommations d’alcool. La première étude de cette thèse explorait donc les liens entre l’usage d’alcool à risque et les relations romantiques auprès d’un échantillon d’étudiants, de manière transversale, puis à un an de suivi. Les données utilisées ont été collectées dans le cadre du volet français du projet international World Mental Health College Student Survey, une enquête par questionnaire en ligne avec suivi annuel, visant à caractériser les besoins en santé mentale des étudiants. L’usage d’alcool à risque était associé à des relations romantiques instables, ainsi qu’à un stress important concernant sa propre vie amoureuse. Cependant, les associations à long terme n’étaient plus significatives après ajustement sur la santé mentale vie entière. Ces résultats soulignent l'importance de prendre en compte des niveaux de consommation inférieurs à ceux d'un trouble de l'usage. En effet, tandis que la majorité de la population va expérimenter au moins une substance psychoactive au cours de sa vie, généralement l’alcool, seules certaines personnes développeront un trouble associé. Ainsi, s’intéresser aux différents niveaux d’usage avant l’apparition du trouble, et plus particulièrement aux transitions entre ces niveaux, revêt une importance particulière dans la compréhension des trajectoires de consommation et dans leur prévention. À cet égard, identifier des facteurs associés aux différentes transitions semble essentiel, et ce dès la transition du non-usage à l’expérimentation. La deuxième étude de cette thèse visait à examiner les liens entre l’utilisation des réseaux sociaux et l’expérimentation de substances au début de l’adolescence. L'exploration de cet environnement, encore peu investigué, semblait d'autant plus pertinente en raison de sa popularité auprès des adolescents et de sa propension à relayer du contenu impliquant des substances. Ainsi, les données utilisées ont été recueillies dans le cadre de l’enquête multicentrique Cyberlife (2019-2023). À partir des réponses auto-rapportées par des collégiens, l’étude a mis en évidence que : (1) la multiplication de comptes sur des sites différents ; (2) l’utilisation de certains réseaux sociaux comme Instagram et TikTok ; et (3) le fait de suivre des créateurs ayant déjà publié du contenu impliquant des substances, entraînaient un risque accru d’expérimenter au moins une substance parmi celles étudiées. Cette thèse met en évidence la nécessité de s’intéresser davantage aux niveaux d’usage en deçà du seuil diagnostic du trouble de l’usage. Ainsi, l’exploration des transitions entre ces niveaux et les facteurs qui y seraient associés pourrait constituer une piste à approfondir à travers de futures recherches, afin de mieux comprendre les trajectoires de consommation et orienter en conséquence les efforts de prévention. Par ailleurs, l’étude des réseaux sociaux en lien avec l’expérimentation des substances à l’adolescence revêt un intérêt particulier et mériterait d’être approfondie en améliorant la mesure de leur utilisation, ainsi qu’en intégrant d’autres facteurs qui pourraient contribuer aux associations observéesAlcohol, tobacco, cannabis and, more recently, e-cigarettes are among the most widespread psychoactive substances in France. The first uses occur mostly at an early age, starting in middle school, and increase through to early adulthood. However, early initiation of consumption is associated with an increased risk of developing substance use disorders, leading to significant negative consequences for both the individual and their daily functioning. These consequences can also arise from lower levels of consumption and affect various areas of life, including interpersonal relationships. These relationships are particularly important during emerging adulthood, a period also marked by an increase in alcohol use. Therefore, the first study of this thesis aimed to explore the links between risky alcohol use and romantic relationships in a sample of students, first cross-sectionally, and then at one-year follow-up. The data were collected as part of the French portion of the international World Mental Health College Student Survey, an online survey with annual follow-up, aimed at characterizing the mental health needs of students. Risky alcohol use was associated with unstable romantic relationships, as well as high stress about one's love life. However, the long-term associations were no longer significant after adjustment for lifetime mental health disorders. These results highlight the importance of considering consumption levels below the diagnostic threshold for substance use disorders. Indeed, while the majority of the population will experiment with at least one psychoactive substance over their lifetime, usually alcohol, only some individuals will develop a related substance use disorder. Thus, focusing on the different levels of use before the onset of a disorder, and more specifically on the transitions between these levels, appears particularly relevant for understanding consumption trajectories and preventing substance use disorders. In this regard, identifying factors associated with these transitions seems essential, starting with the transition from non-use to experimentation. The second study presented in this thesis examined the links between social media use and substance experimentation in early adolescence. The exploration of this environment seemed particularly relevant due to its popularity with adolescents and its propensity to share content involving substances. Accordingly, data collected from the multi-center Cyberlife survey (2019-2023) were used to explore these links. Based on middle school students' self-reported responses, the study highlighted that: (1) having multiple accounts on different platforms; (2) using certain social media sites such as Instagram and TikTok; and (3) following content creators who had previously posted about substances, led to an increased risk of experimenting with at least one of the substances studied. This thesis highlights the need to focus on levels of use below the diagnostic threshold for substance use disorders. Further exploration of the transitions between these levels, and the factors associated with them, could be an important avenue for future research. Improving the current understanding of consumption trajectories is crucial for guiding prevention efforts. Additionally, the study of social media in relation to substance experimentation in adolescence is of particular interest and deserves further exploration. However, better measurement of social media use is essential, as is the integration of other factors into the analyses that could contribute to the observed associations
5
Ramachandran, Preethi. "Cytoskeletal Regulation and Morphogen Signaling During Synaptic Outgrowth at the Drosophila Larval Neuromuscular Junction : A Dissertation". eScholarship@UMMS, 2009. https://escholarship.umassmed.edu/gsbs_diss/442.
Texto completo da fonteResumo:
Synaptic plasticity, in its broadest sense, can be defined as the ability of synapses to be modified structurally and functionally in response to various internal and external factors. Growing evidence has established that at the very core of these modifications are alterations in the cytoskeletal architecture. This discovery has led to the unearthing of a number of signaling pathways that might be involved in cytoskeletal regulation and also in the regulation of other aspects of synapse development and plasticity. In this regard, polarity proteins and secreted morphogens such as the Wnt proteins, typically involved in embryonic development, are emerging as critical determinants of synaptic growth and plasticity. However, their mechanism of action at synapses needs further investigation. Additionally, not much is known about how these morphogens are secreted or transported across synapses. Using the Drosophila larval NMJ as a model system, I have addressed aspects related to the issues mentioned above in the subsequent body of work. In the first half of my thesis, I have uncovered a role for the aPKC/Baz/Par-6 polarity protein complex in the regulation of the postsynaptic actin cytoskeleton in conjunction with the lipid and protein phosphatase PTEN. In the second half of my thesis, I have contributed to the elucidation of mechanisms underlying the secretion of Wg, the Drosophila Wnt homolog. Our findings suggest that Wnts might be secreted via a previously unidentified mechanism involving the release of exosome like vesicles from the presynapse and this process requires Evi/Wntless (Evi), a protein dedicated to Wnt secretion. Alterations in signaling pathways and aberrant cytoskeletal regulation lead to a variety of neurological disorders. The body of work in this thesis will provide a deeper understanding of the mechanisms involved in synaptic plasticity and provide a basis for uncovering similar pathways in the context of vertebrate synapses.
6
Buczek-Thomas, Jo Ann. "Characterization of the Hypersensitive Response of Glycogen Phosphorylase to Catecholamine Stimulation in Primary Culture Diabetic Cardiomyocytes: A Thesis". eScholarship@UMMS, 1992. https://escholarship.umassmed.edu/gsbs_diss/93.
Texto completo da fonteResumo:
The primary goal of my thesis research was to characterize the basis for the hypersensitive response of glycogen phosphorylase to catecholamine stimulation in primary culture diabetic cardiomyocytes. Toward this goal, I have investigated several key regulatory sites in this signaling pathway which could promote the hypersensitive activation of phosphorylase. Specifically, I investigated (1) which adrenergic receptors are involved in mediating the hypersensitive response of glycogen phosphorylase to epinephrine stimulation; (2) whether the presence of fatty acid metabolites affects phosphorylase activation; (3) whether the hypersensitive response of phosphorylase results from altered signal transduction through the β-adrenergic receptor system or from a post-receptor defect; and (4) the potential role for phosphorylase kinase in mediating the hypersensitive response of phosphorylase to catecholamine stimulation.
The basis for adrenergic receptor mediation of the catecholamine-induced activation of glycogen phosphorylase was investigated in adult rat cardiomyocytes isolated from normal and alloxan-diabetic animals. Cells derived from diabetic animals exhibited a hypersensitive response to epinephrine stimulation which was apparent 3 hours after cell isolation and was further enhanced upon maintenance of the myocytes in culture for 24 hours. Normal cells initially lacked the hypersensitive response to epinephrine stimulation although upon maintenance of these cells in culture for 24 hours, the hypersensitive response was acquired in vitro. To assess alpha- and beta- adrenergic mediation of the response, normal and diabetic cardiomyocytes were incubated with propranolol, a β-receptor antagonist, prior to direct α1receptor stimulation with phenylephrine. Both normal and diabetic myocytes failed to undergo activation of phosphorylase in 3 or 24 hour cell cultures. In addition, the effects of epinephrine on phosphorylase activation were completely inhibited by propranolol whereas prazosin, an α-receptor antagonist, was unsuccessful. This data suggests that the hypersensitive response of glycogen phosphorylase in normal and diabetic cardiomyocytes is solely mediated through β-adrenergic receptor activation.
Since the accumulation of various fatty acid metabolites can affect certain enzymes and signal transduction pathways within the cell, the potential effect of various fatty acid metabolites on phosphorylase activation was investigated. To determine the potential effects of fatty acid metabolites on phosphorylase activation in cultured cardiomyocytes, normal and alloxan-diabetic cells were incubated with either carnitine or palmitoylcarnitine prior to stimulation with epinephrine. Pretreatment of cardiomyocytes with or without carnitine or palmitoylcarnitine for 3 or 24 hours before epinephrine stimulation failed to alter phosphorylase activation. The addition of exogenous carnitine in the absence and presence of insulin was also unsuccessful in attenuating the hypersensitive phosphorylase activation response in 3 and 24 hour, normal and alloxan-diabetic derived cardiomyocytes. To determine if carnitine palmitoyltransferase 1 (CPT-1) activity was responsible for the hypersensitive response of phosphorylase in the diabetic myocytes, both normal and diabetic myocytes were maintained for 3 and 24 hours in the absence and presence of etomoxir, a CPT-1 inhibitor. Subsequent activation of phosphorylase by epinephrine in normal and diabetic myocytes was unaltered in the presence of etomoxir. Collectively, these data fail to support a critical role for fatty acid metabolite involvement in the hypersensitive activation of glycogen phosphorylase in acute, alloxan-diabetic cardiomyocytes.
To assess potential G-protein involvement in the response, normal and diabetic-derived myocytes were incubated with either cholera or pertussis toxin prior to hormonal stimulation. Pretreatment of cardiomyocytes with cholera toxin resulted in a potentiated response to epinephrine stimulation whereas pertussis toxin did not affect the activation of this signaling pathway. To determine if the enhanced response of phosphorylase activation resulted from an alteration in adenylyl cyclase activation, the cells were challenged with forskolin. After 3 hours in primary culture, diabetic cardiomyocytes exhibited a hypersensitive response to forskolin stimulation relative to normal cells. However, after 24 hours in culture, both normal and diabetic myocytes responded identically to forskolin challenge. The present data suggest that a cholera toxin sensitive G-protein mediates the hypersensitive response of glycogen phosphorylase to catecholamine stimulation in diabetic cardiomyocytes. This response, which is present in alloxan-diabetic cells, and is induced in vitroin normal cardiomyocytes, is primarily due to a defect at a post-receptor site.
To assess the role of phosphorylase kinase in the hypersensitive activation of glycogen phosphorylase in the diabetic heart, phosphorylase kinase activity was measured initially in perfused hearts (to optimize the assay parameters) and subsequently in primary culture cardiomyocytes. Results from these experiments demonstrate that the present method for measuring phosphorylase kinase activity is a reliable indicator of the enzyme's activity in the heart, although the assay conditions must be further optimized before this system can be applied to the measurement of phosphorylase kinase activity in primary cultured cardiomyocytes.
7
Bei, Yanxia. "Analysis of Polarity Signaling in Both Early Embryogenesis and Germline Development in C. Elegans: A Dissertation". eScholarship@UMMS, 2005. https://escholarship.umassmed.edu/gsbs_diss/147.
Texto completo da fonteResumo:
In a 4-cell C. elegans embryo the ventral blastomere EMS requires polarity signaling from its posterior sister cell, P2. This signaling event enables EMS to orient its division spindle along the anterior-posterior (A/P) axis and to specify the endoderm fate of its posterior daughter cell, E.
Wnt pathway components have been implicated in mediating P2/EMS signaling. However, no single mutants or various mutant combinations of the Wnt pathway components disrupt EMS polarity completely. Here we describe the identification of a pathway that is defined by two tyrosine kinase related proteins, SRC-1 and MES-1, which function in parallel with Wnt signaling to specify endoderm and to orient the division axis of EMS. We show that SRC-1, a C. elegans homolog of c-Src, functions downstream of MES-1 to specifically enhance phosphotyrosine accumulation at the P2/EMS junction in order to control cell fate and mitotic spindle orientation in both the P2 and EMS cells.
In the canonical Wnt pathway, GSK-3 is conserved across species and acts as a negative regulator. However, in C. elegans we find that GSK-3 functions in a positive manner and in parallel with other components in the Wnt pathway to specify endoderm during embryogenesis. In addition, we also show that GSK-3 regulates C. elegans germline development, a function of GSK-3 that is not associated with Wnt signaling. It is required for the differentiation of somatic gonadal cells as well as the regulation of meiotic cell cycle in germ cells. Our results indicate that GSK-3 modulates multiple signaling pathways to regulate both embryogenesis and germline development in C. elegans.
8
Audrain, Susan Connor. "Ethics in Technical Communication: Historical Context for the Human Radiation Experiments". Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc4820/.
Texto completo da fonteResumo:
To illustrate the intersection of ethical language and ethical frameworks within technical communication, this dissertation analyzes the history and documentation of the human radiation experiments of the 1940s through the 1970s. Research propositions included clarifying the link between medical documentation and technical communication by reviewing the literature that links the two disciplines from the ancient period to the present; establishing an appropriate historiography for the human radiation experiments by providing a context of the military, political, medical, and rhetorical milieu of the 1940s to the 1970s; closely examining and analyzing actual human radiation experiment documentation, including proposals, letters, memos, and consent forms, looking for established rhetorical constructions that indicate a document adheres to or diverts from specific ethical frameworks; and suggesting the importance of the human radiation documents for studying ethics in technical communication. Close rhetorical analysis of the documents included with this project reveals consistent patterns of metadiscourse, passive and nominal writing styles, and other rhetorical constructions, including negative language, redundancies, hedges, and intensifiers, that could lead a reader to misunderstand the writer's original ethical purpose. Ultimately this project finds that technical communicators cannot classify language itself as ethical or unethical; the language is simply the framework with which the experimenters construct their arguments and communicate their work. Technical communicators can, however, consider the ethical nature of behavior according to specific ethical frameworks and determine whether language contributes to the behavior.
Livros sobre o assunto "Substance experimentation"
1
Wayne, Hall, ed. Addiction neuroethics: The promises and perils of neuroscience research on addiction. New York: Cambridge University Press, 2012.
Encontre o texto completo da fonte
2
Affairs, United States Congress Senate Committee on Governmental. Human radiation and other scientific experiments: The federal government's role : hearing before the Committee on Governmental Affairs, United States Senate, One Hundred Third Congress, second session, January 25, 1994. Washington: U.S. G.P.O., 1995.
Encontre o texto completo da fonte
3
Genetic research on addiction: Ethics, the law, and public health. Cambridge: Cambridge University Press, 2012.
Encontre o texto completo da fonte
4
Nutt, David J., e Liam J. Nestor. Neurobiological processes in addiction. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198797746.003.0004.
Texto completo da fonteResumo:
The brain is involved in controlling necessary motivational and cognitive processes optimized for survival. These processes can be disrupted by substances of addiction. The key neural substrates underlying these processes are made up of a network of four independent and overlapping brain circuits. These circuits govern reward processing, motivation and/or drive, learning and memory, and cognitive control. Anomalies within these circuits may also pre-date the addiction state, and facilitate the progress from experimentation to substance addiction. The subsequent excessive and chronic use of substances further exacerbates these abnormalities. Therefore, these brain circuits and key psychological processes related to their functioning must be understood if we are to develop and test new pharmacological and psychological treatment approaches in substance addiction.
5
Kobeissy, Firas H. Psychiatric Disorders: Methods and Protocols. Humana Press, 2016.
Encontre o texto completo da fonte
6
Hall, Wayne, e Adrian Carter. Addiction Neuroethics: The Promises and Perils of Neuroscience Research on Addiction. Cambridge University Press, 2011.
Encontre o texto completo da fonte
7
Hall, Wayne, e Adrian Carter. Addiction Neuroethics: The Promises and Perils of Neuroscience Research on Addiction. Cambridge University Press, 2012.
Encontre o texto completo da fonte
8
Hall, Wayne, e Adrian Carter. Addiction Neuroethics: The Promises and Perils of Neuroscience Research on Addiction. Cambridge University Press, 2011.
Encontre o texto completo da fonte
9
Illes, Judy, Wayne Hall e Adrian Carter. Addiction Neuroethics: The Ethics of Addiction Neuroscience Research and Treatment. Elsevier Science & Technology Books, 2011.
Encontre o texto completo da fonte
10
Ellens, J. Harold, ed. Seeking the Sacred with Psychoactive Substances. Praeger, 2014. http://dx.doi.org/10.5040/9798216985877.
Texto completo da fonteResumo:
Can drugs be used intelligently and responsibly to expand human consciousness and heighten spirituality? This two-volume work presents objective scientific information and personal stories aiming to answer the question. The first of its kind, this intriguing two-volume set objectively reports on and assesses this modern psycho-social movement in world culture: the constructive medical use of entheogens and related mind-altering substances. Covering the use of substances such as ayahuasca, cannabis, LSD, peyote, and psilocybin, the work seeks to illuminate the topic in a scholarly and scientific fashion so as to lift the typical division between those who are supporters of research and exploration of entheogens and those who are strongly opposed to any such experimentation altogether. The volumes address the history and use of mind-altering drugs in medical research and religious practice in the endeavor to expand and heighten spirituality and the sense of the divine, providing unbiased coverage of the relevant arguments and controversies regarding the subject matter. Chapters include examinations of how psychoactive agents are used to achieve altered states in Judaism, Christianity, Islam, and Buddhism as well as in the rituals of shamanism and other less widely known faiths. This highly readable work will appeal to everyone from high school students to seasoned professors, in both the secular world and in devoted church groups and religious colleges.
Capítulos de livros sobre o assunto "Substance experimentation"
1
Chouroulinkov, Irene. "The need for animal experimentation in studying the carcinogenic risk of substances". In The Importance of Animal Experimentation for Safety and Biomedical Research, 199–209. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-1904-4_22.
Texto completo da fonte
2
Hardon, Anita. "Chemical Creativity". In Critical Studies in Risk and Uncertainty, 247–79. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-57081-1_8.
Texto completo da fonteResumo:
Abstract The microdosing of mind-altering substances, like LSD and magic mushrooms, is a trend among young creatives, who report enhanced creativity, improved focus, and other productivity-enhancing effects. This chapter, Chemical Creativity, describes how both users and researchers have been exploring the range of effects of microdosing, including through more experimental ethnographic research. Using virtual ethnography, we analyzed drug users’ narratives of their personal experiences, practices, and motivations with microdosing. We also collaborated with participants using online platforms focused on drug experimentation to generate data, combining their collective experiences while acknowledging individual expertise. Finally, we reviewed research on clinical trials that compare the effects of psychoactive substances, like LSD, with placebos. What emerges is a clearer picture of the benefits of microdosing, how dosages are tweaked, and how users engage in “harm reduction from below” by spreading their cautionary tales within the microdosing world. In so doing, we offer a glimpse into how this relatively new practice develops, as it gains popularity with both laypeople and the academic and scientific communities.
3
Lydall, Greg, e Kelly Clarke. "Substance Misuse Psychiatry". In Oxford Assess and Progress: Psychiatry. Oxford University Press, 2014. http://dx.doi.org/10.1093/oso/9780199665662.003.0021.
Texto completo da fonteResumo:
Clinicians in all areas of medicine are likely to encounter people with substance misuse issues, so an understanding of the key issues is essential. Human beings have used intoxicating substances, such as alcohol, nicotine, cannabis, and heroin, for millennia. Motivations might include experimentation, pleasure, social enhancement, or for physical or psychological pain management. Some people who use these legal and illegal substances experience problems related to their use, including loss of control, adverse consequences, withdrawals or cravings, damaged end organs, risky behaviour, and premature death. Substance misuse impacts not only on individual physical and mental health but also upon families and wider society by increased healthcare, criminal justice, social services, and unemployment costs. Drug and alcohol problems affect between 10% and 25% of the population each year, and up to 35% of people have ever used illicit drugs. Alcohol, an intoxicating sedative, is the most commonly used drug, with 25% of the UK population drinking above ‘low-risk’ limits. In England in 2010 there were an estimated 300 000 opiate, crack-cocaine, and injecting drug users, and only half were in treatment. Substance misuse is commonly associated with physical and mental health co-morbidity. The prevalence of co-existing mental health and substance use problems (termed ‘dual diagnosis’) may affect between 30% and 70% of those presenting to healthcare and social care settings. In general, four interrelationships in dual diagnosis are recognized: • substance use leading to social problems and psychological symptoms not amounting to a diagnosis • substance use leading to social dysfunction and secondary psychiatric and physical illness • substance use exacerbating an existing mental or physical health problem and associated social functioning • primary psychiatric illness precipitating substance misuse which may also be associated with physical illness and affect social ability. Given the array of substance misuse problems, an individual treatment approach is essential and may involve psychological, pharmacological, and social intervention. An empathic, non-judgemental clinical approach is essential to engage people with substance misuse problems. Motivational interviewing is an evidence-based talking therapy to help people in denial about their problems make changes for themselves and avoids imposing change prematurely.
4
Warsh, Cheryl Krasnick. "The Ticking Time Bomb". In Frances Oldham Kelsey, the FDA, and the Battle against Thalidomide, 239–59. Oxford University PressNew York, 2024. http://dx.doi.org/10.1093/oso/9780197632543.003.0018.
Texto completo da fonteResumo:
Abstract Diethylstilbestrol (DES) was a synthetic estrogen intended to prevent miscarriage and menopausal symptoms, and to fatten livestock. In the 1940s, researchers believed DES should be administered to all pregnant women to prevent pregnancy disorders. However, DES caused cervical cancer, apparent at puberty. Kelsey headed a DES task force, concluding that its use should be limited, if not banned. The outrage on DES and the Tuskegee syphilis experiments led to public calls for human experimentation protocols, which passed in 1972. DES also was a cattle feed additive, and the agricultural lobby fought its ban. Environmental advocates cited the Delaney clause, which stated any substance causing cancer must be banned.
5
Singh, Yuvraj. "Bill Clinton’s First Inaugural Address". In My Fellow Americans, 547–50. Oxford University PressNew York, 2025. http://dx.doi.org/10.1093/oso/9780197644997.003.0114.
Texto completo da fonteResumo:
Abstract This chapter details Bill Clinton’s First Inaugural Address, which was just fourteen minutes long, but did not lack substance. After thanking his predecessor and others of his generation for their service and sacrifice, Clinton proclaims that a new generation has come to power, a generation raised in the shadow of the Cold War. Clinton invokes George Washington and Thomas Jefferson and pays homage to Abraham Lincoln’s Gettysburg Address by calling for a celebration of the mystery of American renewal. Echoing John F. Kennedy’s inaugural address, Clinton emphasizes the necessity of sacrifice and service. Clinton positions himself within a specific political genealogy that stood for liberalism’s deepest values by summoning the themes of rebirth, experimentation, and sacrifice.
6
"Regional SME and Development Agencies". In Advances in Business Information Systems and Analytics, 35–67. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2641-5.ch002.
Texto completo da fonteResumo:
In Chapter 2, the author shared research evidence on the role of regional SME and development agencies, which are profiled as factors of SME support, regional development, and improvement of competitiveness. The author inquires whether it is possible to experiment with new institutional concepts with a basic role given to the agencies as facilitators of social-economic development reaching out locally, regionally, globally, and in particular, rurally. Such institutions have as their substance a series of development interventions that flow and merge into each other without sharp divisions that might inhibit entrepreneurship and, as will be seen later, rural development. What is proposed here is not a new institution as such but, rather, a new fashion of using the existing development infrastructure. The author develops this approach as experimentation with institutions, which is meant mainly to provide an insight into the fragmentary function of the common social-economic development rather than to propose a totally new method of developing an economy at the local and rural level.
7
""Slippery Substances"". In Instruments and Experimentation in the History of Chemistry. The MIT Press, 2000. http://dx.doi.org/10.7551/mitpress/3818.003.0008.
Texto completo da fonte
8
Francis, Leslie P., e John G. Francis. "Experimentation and State Variations". In States of Health, 245–83. Oxford University Press, 2024. http://dx.doi.org/10.1093/oso/9780197538654.003.0009.
Texto completo da fonteResumo:
Abstract The federal government uses its commerce clause authority to regulate marketing of drugs and devices and to prohibit use of controlled substances deemed to lack medical use. States have pushed back against this federal authority, enacting statutes permitting medical or recreational marijuana use and granting gravely ill patients the right to try unproven treatments. Data are urgently needed to evaluate these experiments. States have played many roles in addressing the opioid crisis, including cooperating in settlements, sometimes competing to obtain better deals, and sometimes pushing back on federal approvals. For their part, states also acted inadequately in addressing the crisis. We argue in this chapter that states should be permitted to experiment to increase access to medical products, conditioned on appropriate assessment of risks, costs, and efficacy. This is a benefit of federalism. However, it is also unjust for states to deny their residents access to federally approved treatments supported by adequate evidence.
9
Tochka, Nicholas. "How the Counterculture Dug Deeper". In Rocking in the Free World, 77—C4F2. Oxford University Press, 2023. http://dx.doi.org/10.1093/oso/9780197566510.003.0005.
Texto completo da fonteResumo:
Abstract During a remarkable four-year period from 1966 to 1969, rock seemed to have revolutionary potentials. The “rock revolution” (to use the title of one early book about the music) had allowed listeners to discover the reality of social life lurking underneath the surface of the everyday, whether by ingesting psychedelics, staging utopian dances, exploring hidden states of consciousness, engaging in absurdist political theatre, or broadcasting important social messages. This chapter examines rock dances, musicians’ experimentation with non-Western musics, larger countercultural experimentation with consciousness-altering substances, and the recruitment of music to political causes to outline how commentators in Sixties America viewed the promise of rock music as a political force.
10
Revusky, Sam. "Chemical Aversion Treatment of Alcoholism". In Conditioned Taste Aversion Behavioral and Neural Processes, 445–72. Oxford University PressNew York, NY, 2008. http://dx.doi.org/10.1093/oso/9780195326581.003.0021.
Texto completo da fonteResumo:
Abstract Since the 1970s, it has become solidly established that CTA (conditioned taste aversion) is, by far, the most potent type of learning. CTAs occur when an animal tastes something, becomes sick through some external means (e.g., injection of a toxin), and then avoids substances with that taste. In the chemical aversion treatment (CAT) of alcoholism in the 1930s, a CTA method was used to induce aversions to the flavors of alcoholic beverages in order to facilitate abstinence from alcohol. Because I want to explore the relationship between CAT and sub-human CTA experimentation, the term “CTA” will be used here to refer to subhuman experimental procedures unless otherwise indicated by the context. Also, although CAT is a behavioral intervention, I will not refer to it as such here because I want to contrast it with other types ofbehavioral interventions to treat alcoholism.
Trabalhos de conferências sobre o assunto "Substance experimentation"
1
Son, Seyul, Yanli Wang e N. C. Goulbourne. "A Structure Based Constitutive Model for Bat Wing Skins, A Soft Biological Tissue". In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40924.
Texto completo da fonteResumo:
Bat wing skin is a soft biological tissue that is used to enable flight (amongst other physiological roles) in bats such as the Glossophaga Soricina. To describe and predict wing behavior during flight, a high fidelity constitutive model validated by rigorous experimentation is required. Understanding the role that the tissue microstructure plays in achievable flight patterns and maneuverability will bring closer understanding of adaptations between species that yield specific flight behaviors and will also provide a template for developing synthetic skins for biomimicry in unmanned micro air vehicles. A structural continuum model that incorporates principal structural features of the wing skin can potentially provide a link between structure and functionality. Mesoscopic elastin fiber bundles on the order of hundreds of microns are the key constituents in the structure of bat wing. They are embedded in a base matrix composed by elastic ground substance and randomly oriented collagen fibers. The wing sweeps through very large deformations during flight and the fiber bundles undergo finite strains and large rotations presumed affine in the current treatment. To date, all the biological materials studied and modeled are comprised of stiff collagen fibers. The wing skin, on the other hand, is modeled as hyperelastic with distributed elastin fiber bundles with orientations belonging to two disparate families. Two families of fiber bundles have shown prominent difference in mechanical properties. More importantly, the bundle diameters vary dramatically with respect to bundle orientation even within each family. A mathematical treatment is formulated in this paper to capture the overall effect of distribution of diameters and distribution of orientations of fiber bundles based on the framework of Gasser et al [1]. This formulation is suitable in a general case when two fiber properties both vary spatially and they can be described using distribution functions such as Von Mises distribution.
2
Castro, Michelle, Ricarda Pritschmann, Meredith Berry, Richard Yi e Ali Yurasek. "Associations of Cannabis Use Motives and Cannabis Demand in Young Adults". In 2021 Virtual Scientific Meeting of the Research Society on Marijuana. Research Society on Marijuana, 2022. http://dx.doi.org/10.26828/cannabis.2022.01.000.02.
Texto completo da fonteResumo:
Background: Cannabis is the most commonly used illicit substance among young adults and is associated with a variety of negative consequences. Studies have shown that both cannabis demand and certain cannabis motives are associated with higher levels and frequency of cannabis use, as well as associated problems. No study has yet to examine the relationship between cannabis use motives and cannabis demand. The purpose of the current study was to examine the associations between individual cannabis motives and cannabis demand. Methods: Data were collected from 95 young adult cannabis users who reported using cannabis at least once in the last 30 days. (M age = 20.63; Female = 50.5%; M cannabis use days per month = 14.64). Participants completed questionnaires assessing cannabis use frequency, cannabis use motives, and a cannabis purchase task. Amplitude, representative of the amount consumed at an unrestricted price, and persistence, representative of sensitivity to escalating price, were calculated and used in the analyses. Results: Initial correlational analyses demonstrated significant relationships between demand and total number of cannabis motives and conformity, enjoyment, coping, experimentation, boredom, celebration, and sleep motives (ps < .05). A series of hierarchical linear regressions were conducted to determine the specific associations between the aforementioned individual cannabis motives and amplitude and persistence. Step one controlled for age, gender, and cannabis use frequency, and the motives were added in step two. Regression models indicated that total number of motives, enjoyment, conformity, and coping motives were significant predictors of persistence even after controlling for cannabis use frequency. Motives were not significant predictors of amplitude. Conclusion: Findings from this study suggest that young adults who use cannabis for enjoyment, conformity, or coping reasons may experience greater reinforcement efficacy of cannabis which may place them at increased risk to develop cannabis use disorder or other related problems associated with their use. Further, young adults with these cannabis use motives may be less sensitive to increases in price and continue to purchase cannabis at higher prices. These findings can be used to inform cannabis interventions by targeting specific motives for use.
3
Fakheri, Ahmad, Wael Abou-Zaid e Jeries Abou-Hanna. "Virtual Instrumentation and Virtual Experimentation". In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14501.
Texto completo da fonteResumo:
A Virtual Instrument (VI) that is developed to acquire and analyze data from a physical system can be disconnected from the system and modified into a Virtual Experiment (VE). This can be achieved by replacing the input to the sensors with values that are arrived at by modeling the system. To be able to develop virtual experiments in thermodynamics, fluids or heat transfer, VIs are needed for the determination of thermodynamic and transport properties of different substances. The code REFPROP by NIST is used to develop the needed VIs for determining the thermodynamic and transport properties. The enhancement of the experimentation with virtual experiments is developed for an experimentation course where students perform experiments virtually and then make the transition to the actual lab and conduct experiments that mirror the virtual one.
4
Elsharafi, Mahmoud, Ali Elmozughi, Pranaya Pokharel, Madison Krahl, Musaad Aldawsari, Clayton Holmes e Theo Rolle. "Experimental Analysis for a New Design of Thermal Energy Storage System". In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-67656.
Texto completo da fonteResumo:
Abstract Accumulative knowledge on Thermal Energy Storage (TES) is imperative in society today because technology is ever expanding, opening doors for improved innovation that is more sustainable to our environment. TES has a multitude of uses; from simply boiling a kettle of water on a stove to more complex applications such as solar power generation. This research focuses on the application of a thermal energy storage unit introduced to a selected Phase Change Material (PCM) to undergo controlled experimentation. It helpful to gain understanding of how the TES unit will perform in a typical laboratory environment. A PCM is any substance capable of absorbing or releasing sufficient energy to undergo a phase transition. For specified purposes of this work was, the relevant states of matter liquid and solid; hence the use of a paraffin wax was the ideal for the experimental work model where the phase transition from solid to liquid occurs in a relatively low temperature. The objective of this work was determining the amount of energy that can be stored, and the power that can be generated by using paraffin wax. The setup of the experimental work for this project was consisting of a wax chamber, corrugated steel plates, and gaskets compressed within two plexiglass frames with an inlet and outlet. Tap water was used the medium of transferring thermal energy, and a JULABO heating unit was used to generate enough thermal energy for the steel plates. PCM was used to absorb the energy and transfer it to the cold water during the PCM transformation. A normal faucet was to provide cool enough water to lower the temperature within the system initiating the liquid to solid phase transition. Hoses was used to connect the main TES unit, JULABO unit, and faucet, as well as allowing flow throughout the system. Experiential work and calculation model results shows that the energy recovery was effected by flow rates, melting temperatures, and PCM. Other factors were considered in this work including mass, volume, density, specific heat, latency, turbulence flow, Reynolds number, limitations, and factor of safety. The results of this work can be used to get useful energy especially in isolated location such as desert, ships in occasion, and military locations.
5
Komaki, Kanae, Mitsuru Shimazu, Shunsuke Kondo, Yosuke Onishi, Satoshi Furuta e Rei Arai. "Laboratory Experimentations for New Hydrothermal Monitoring Systems Using ADCPs". In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10610.
Texto completo da fonteResumo:
Deep ocean mining in a hydrothermal area needs careful environmental impact assessments in terms of preservation and mitigation of biodiversity. The General Environmental Technos Co. Ltd., or KANSO TECHNOS, for short, has participated in environmental impact assessments in hydrothermal areas in the Izu-Ogasawara and the East China Sea areas (Ishida et al., 2011). Through the experience, we suggest a method of using acoustic systems such as acoustic Doppler current profilers (ADCPs) for monitoring of suspended matters and benthos in hydrothermal areas. Thus, we try to do in-situ observations, called Tow-yo (or Towing) observations with ADCPs (Komaki and Ura, 2009; Komaki et al., 2010). This system has a great advantage in enabling the measurement of great environmental factors, echo intensity and current velocity in a large range. To confirm exactly what the substances are and how large they are from the measured echo intensity data, we tried laboratory experiments in water tanks with echo sounders and turbidity sensors. These results will finally be integrated in a simulation model to predict substances from in-situ data in deep water for future monitoring systems.
6
Popescu, Jeni A., Valeriu A. Vilag, Romulus Petcu, Valentin Silivestru e Virgil Stanciu. "Researches Concerning Kerosene-to-Landfill Gas Conversion for an Aero-Derivative Gas Turbine". In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-23436.
Texto completo da fonteResumo:
The aero-derivative gas turbine represents an advanced solution for technologic transfer from aeronautics to industrial applications, including high efficiency, reduced dimensions and high reliability. The paper, as result of a research project, is focused on an application using an aero-derivative gas turbine as an installation for CO2 rich landfill gas valorization. The paper also presents the potential for landfill gas production in Romania, in the context of the requirements imposed by the environmental laws. A calculation is realized based on demographic statistics, showing the most suitable areas in the country for obtaining the landfill gas. The first part is dedicated to a comparative examination of classical liquid fuel, kerosene, and two gaseous fuels, methane and landfill gas with equal volume ratio of methane and carbon dioxide, analyzed from the point of view of their combustion performances in the gas turbine, with the help of CEA program developed by NASA. Considering the nowadays utilization of CFD simulations for design purpose in many activity fields from the engineering domain, the results provided by the CEA program, along with the ones provided by the gas turbine’s producer, were considered input data for the numerical approaches of the combustion process of methane and landfill gas in the known combustion chamber using a commercial CFD code. The main goal of the CFD applications is to determine the optimum geometric configuration of the new injection system in order to obtain a stabilized process and high performances in safety conditions, for low working regimes and nominal regime, as defined by experimental data and producer’s recommendations. Previous successful experimentations on test bench following the combustion simulation of methane gas and the encouraging results from the CFD simulations lead to new experimentations of the gas turbine working on landfill gas in order to validate the numerical approaches, activity described in the third part of the paper. A technological fueling scheme was designed, the geometrical adjustments were made according to previous simulations and the landfill gas was simulated using a homogenization device installed on the fuel line for a forced mixing of the two non-reactive substances, methane and carbon dioxide. The gas turbine was prepared and instrumented for bench testing and stable working was obtained for speeds of 27–63% of the nominal one. The conclusions are related to the execution of an installation allowing experimentation of gas turbines working on landfill gas and future researches focusing on tests for higher working regimes.
7
Agaku, Israel, Uyoyo Omaduvie, Constantine Vardavas e Filippos Filippidis. "Cannabis use is associated with reduced harm perception towards illicit drugs and experimentation with new psychoactive substances among European adolescents and young adults". In Annual Congress 2015. European Respiratory Society, 2015. http://dx.doi.org/10.1183/13993003.congress-2015.pa5118.
Texto completo da fonte
8
Costa, Alice Mara Rosário da, Mayra Araújo da Cunha Leite, Ana Luzia Ferreira Farias, Patrick de Castro Cantuária e Sheylla Susan Moreira da Silva de Almeida. "Phytochemical study of the leaves of Artocarpus heterophyllus LAM". In II INTERNATIONAL SEVEN MULTIDISCIPLINARY CONGRESS. Seven Congress, 2023. http://dx.doi.org/10.56238/homeinternationalanais-094.
Texto completo da fonteResumo:
Abstract Medicinal plants are widely used in many parts of the world. In Brazil, due to the influence of indigenous roots, this practice has been widespread until today, especially in northern and northeastern regions, where there is the largest concentration of indigenous tribes still alive. The precariousness of public services in remote communities has resulted in the use of plants for medicinal purposes as the main therapeutic resource of these populations and ethnic groups, given that the presence of knowledge about herbs and plant materials, which is passed on among families, is the primary source of treatment and cure of various diseases based on empirical experimentation in these communities (LEITE, 2014). Thus, it should be noted that the use of plants for curative purposes comes from the earliest reports of human societies and, currently, it can still be observed that the wealth attributed to the ancient knowledge of traditional peoples has been a potentiating factor in innovations in research and the search for new substances from what has already been described in these cultures.
9
Nwaigwe, Kevin N., Nnamdi V. Ogueke, Chibuike Ononogbo e Emmanuel E. Anyanwu. "Performance Study of Anaerobic Digestion of Organic Municipal Waste in Upflow Bioreactor With Central Substrate Dispenser". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64064.
Texto completo da fonteResumo:
A performance study of anaerobic digestion of organic municipal waste in upflow bioreactor with central substrate dispenser is presented. The experimental rig is based on an integrated system of bioreactors consisting of Upflow Bioreactor (UB), Upflow Bioreactor with Central Subtrate Dispenser (UBCSD), and Continous Stirred Tank Reactor (CSTR) each having internal volume of 76 litres, 64.8 litres, and 76 litres respectively. The scheme is used for minimizing the mixing and fouling problems associated with some conventional bioreactors during digestion reaction. Organic municipal waste (OMW) was used to prepare the slurry for the reactors. Microbial reaction was enhanced during operation using a measured quantity (2kg) of substances from the rumen of a newly slaughtered cow. The experimentation from feeder tank to Bioreactors was carried out for a period of 10-days Hydraulic Retention Time (HRT) at 37°C. Effects of some basic parameters affecting anaerobic digestion in terms of biogas production and Chemical Oxygen Demand (COD) reduction were carried out. They include substrate temperature, minimal average temperature, changes in temperature, substrate content and properties, available nutrient, retention time, organic loading rate, pH level, nitrogen inhibition and C/N ratio, substrate agitation, and inhibitory factors. Results showed that UBSCD generated the highest level of Biogas yield of up to 52915 ml, while UB and CSTR yielded 23550ml and 28980ml respectively. Similarly for COD removal, 24343 mg/l, 5775.4 mg/l, and 23155 mg/l were achieved for UBCSD, UB and CSTR respectively from an initial value of 120,320 mg/l. These results show that the use of UBCSD better enhances biofuel production from organic municipal waste.
10
Gutierrez, Gustavo, e Radhames Rodriguez. "Conductivity Measurement of Ferrofluid Using Transient Hot Wire Method". In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43365.
Texto completo da fonteResumo:
Thermal conductivity of the ferrofluids is a difficult property to predict theoretically. Existing models can not explain the real behavior of such fluids and mismatch the results found in the experiments. Experimentation is then the most reliable way to determine the observed enhancement in thermal conductivity of ferrofluids. The transient hot wire method is an experimental technique in which the thermal conductivity is obtained by measuring a temperature change, respect to time in a thin wire, caused by a constant current passing through it. Some advantages of this method are the almost complete elimination of natural convection effects, its fast implementation and its high accuracy. In order to use the transient hot-wire technique in a ferrofluid a modification must be made because the transient hot-wire method cannot be applied to electrical conducting fluids since part of the current will be conducted by the fluid, generating uncertainties in the current passing through the wire. These uncertainties will affect the voltage measurement over predicting the thermal conductivity. To prevent the current to pass through the fluid the hot wire has to be covered with an electrical insulating coating. Then, it is necessary to calibrate the wire with a calibrating constant in order to correct the effect of the coating in the RTD. For calibration purposes, thermal conductivity measurements of known fluids have been carried out. For this purpose, substances like water, toluene acetone and heptane are used. In this study the transient hot-wire method is implemented to measure the thermal conductivity of different water-based ferrofluids and oilbased ferrofluids. Parametric Studies are carried out numerically to understand the effect of the coating in the technique.