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Biomedical subjects

D J Hansen

Publications and source records attributed to D J Hansen.

At least 19 recordsLinked to original sources
PubMed2001

Biological response to variation of acid-volatile sulfides and metals in field-exposed spiked sediments.

Vertical and temporal variations of acid-volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediment can control biological impacts of metals. To assess the significance of these variations in field sediments, sediments spiked with cadmium, copper, lead, nickel, and zinc were deployed in Narragansett Bay for four months and recolonization by benthic organisms investigated. In surface sediments, concentrations of AVS decreased with time whenever AVS exceeded SEM but remained unchanged when AVS was less than SEM; in subsurface sediments, concentrations increased slightly. Concentrations of total SEM decreased with time only in surface sediments in which SEM exceeded AVS. Metals were not detected in interstitial waters of sediments where AVS exceeded SEM but were significant when SEM exceeded AVS and followed the order of solubilities of their sulfides. Concentrations in interstitial waters decreased with time, but exceeded U.S. Environmental Protection Agency chronic water quality criteria for 56 to 119 d. After 119 d, faunal assemblages in all treatments were similar to controls. Lack of biological response was related to vertical distributions of AVS and SEM. Biological exposure took place in near-surface sediments, where AVS exceeded SEM in even the highest treatments. Therefore, concentrations of metals in interstitial waters were low and consequently biological impacts were undetectable.

Acids↗
PubMed1999

Comparative toxicity of fluoranthene to freshwater and saltwater species under fluorescent and ultraviolet light.

The acute and chronic toxicity of fluoranthene was determined for a diverse group of freshwater and saltwater species under both standard laboratory fluorescent light and ultraviolet (UV) light test conditions. Acute tests with 21 species demonstrated that fluoranthene was not lethal within its water solubility limit to most species tested under fluorescent light, but was lethal well below this limit to nearly all of the species tested under UV light. In general, the acute sensitivity of freshwater and saltwater species from the same class was similar, although UV light exposure changed the relative sensitivity of some species. Crustaceans were the most sensitive to fluoranthene, but in the presence of UV light, an oligochaete and a fish were the most sensitive. Overall, UV light increased acute fluoranthene toxicity approximately one to three orders of magnitude. In chronic tests, sublethal concentrations of fluoranthene were toxic under both fluorescent and UV light, but as in most acute tests, UV light increased chronic toxicity approximately an order of magnitude. Comparison of data from tests conducted in the laboratory and outdoors demonstrated that acute toxicity increased with increased UV light intensity.http://link. springer-ny.com/link/service/journals/00244/bibs/37n4p496.++ +html</HEA

Animals↗
PubMed1999

Recommended default methodology for analysis of airborne exposures to mixtures of chemicals in emergencies.

Emergency planning and hazard assessment of Department of Energy (DOE) facilities require consideration of potential exposures to mixtures of chemicals released to the atmosphere. Exposure to chemical mixtures may lead to additive, synergistic, or antagonistic health effects. In the past, the consequences of exposures to each chemical have been analyzed separately. This approach may not adequately protect the health of persons exposed to mixtures. This article presents default recommendations for use in emergency management and safety analysis within the DOE complex where potential exists for releases of mixtures of chemicals. These recommendations were developed by the DOE Subcommittee on Consequence Assessment and Protective Actions (SCAPA). It is recommended that hazard indices (e.g., HIi = Ci/Limiti, where Ci is the concentration of chemical "i") be calculated for each chemical, and unless sufficient toxicological knowledge is available to indicate otherwise, that they be summed, that is, sigma i(n) = 1HIi = HI1 + HI2 + ... + HIn. A sum of 1.0 or less means the limits have not been exceeded. To facilitate application of these recommendations for analysis of exposures to specific mixtures, chemicals are classified according to their toxic consequences. This is done using health code numbers describing toxic effects by target organ for each chemical. This methodology has been applied to several potential releases of chemicals to compare the resulting hazard indices of a chemical mixture with those obtained when each chemical is treated independently. The methodology used and results obtained from analysis of one mixture are presented in this article. This article also demonstrates how health code numbers can be used to sum hazard indices only for those chemicals that have the same toxic consequence.

Air Pollutants↗
PubMed1999

DOE emergency planning & emergency management using emergency response planning guidelines (ERPGS) and temporary emergency exposure levels (TEELs).

Facilities within the Department of Energy community perform emergency management to conform with Federal regulations, internal guidance and good management practice. Emergency management in this context includes hazard analysis, consequence assessment, and development of emergency plans including protective actions for workers, uninvolved workers, and the general public. ERPGs are used as the action level for decision making with regards to accidental chemical releases; AEGLs are also being developed for that purpose. DOE actively participates in the development of ERPGs and AEGLs, however, there is a time gap inherent in the development of community exposure limits (which can be months or years) and the need for community exposure limits (which must be implemented now). In recognition of this problem, the DOE Subcommittee on Consequence Assessment and Protective Actions (SCAPA) has developed a hierarchy of alternate exposure limits (Temporary Emergency Exposure Limits, TEELs) to use as temporary guidance for emergency planning for those chemicals for which an ERPG or an AEGL does not exist. This presentation will discuss DOE's involvement in development of ERPGs and AEGLs, including their application, and will discuss the development and use of TEELs (including advantages and disadvantages).

Air Pollutants↗
PubMed1997

Influence of information related to child physical abuse on professional ratings of adjustment and prognosis.

The study investigates the influence of access to information of a history of physical maltreatment on the evaluative responding of social service and clinical psychology professionals. Written vignettes were used in a 2 x 2 x 2 factorial design to manipulate the: (a) presence/absence of abuse history; (b) presence/absence of behavior problems; and (c) gender of the child. Professionals rated children presented in 12 case vignettes along five treatment-related dimensions: (a) overall adjustment; (b) predicted 6 months temporal stability of behavior; (c) likelihood of treatment referral; (d) expected home intervention success; and (e) expected school intervention success. Four dimensions related to social functioning were also rated, including likelihood of the child being: (a) recommended to serve as assistant to teacher; (b) elected as a school activity team leader; (c) elected as a class officer; and (d) nominated as a candidate for successful completion of a summer camp program. The findings verified the influence of information related to a history of maltreatment of professional judgments, despite matched vignette content for all factors other than maltreatment status. The results suggests a possible failure to recognize that some children have been buffered from the negative effects of abuse and point to the risk of erroneous judgments that may be directed toward maltreated children.

Adult↗
PubMed1996

The influence of case and professional variables on identification and reporting of physical abuse: a study with medical students.

Identification and reporting of suspected cases of maltreatment are important precursors to intervention, as maltreating parents typically do not self-refer for treatment. Professionals from various disciplines are legally mandated to report suspected cases of child maltreatment, yet incidences of abuse can remain unidentified or unreported. Identification of physical abuse often depends on careful consideration of the characteristics of the injuries and the plausibility of the explanations provided for the injuries. Many variables impact identification, as well as the subsequent decision of whether or not to report the case if abuse is suspected. The study examined the influence of three case variables (injury severity, plausibility of explanation, and time to seek medical attention) and two professional variables (gender of subject and amount of clinical experience) on how medical students respond to hypothetical cases of abuse. As part of the study, the responses of medical students were compared to those of practicing physicians. Subjects evaluated 16 different vignettes, each describing an injured child, rated whether injuries may have resulted from physical abuse, and indicated what further action should be taken with the case, including whether it should be reported. Results indicated a significant three-way interaction between injury severity, injury explanation, and delay. Subject gender and amount of clinical experience did not influence identification. Significant positive correlations between identification and reporting were found. Correspondence between the responses of medical students and physicians was quite strong. Implications for clinical training of mandated reporters and directions for future research are discussed.

Adult↗
PubMed1996

Reconsideration of the use of peer sociometrics for evaluating social-skills training. Implications of an idiographic assessment of temporal stability.

Social-skills training studies using sociometric procedures as dependent measures have often yielded mixed results as to the improvement of the subjects. Failure to document improvement in peer acceptance subsequent to behavior change has led some to question the validity of social-skills interventions, whereas others have questioned the psychometric properties of the measures themselves. This study examined the temporal stability of the two major types of peer measures used in social-skills interventions studies; peer-nomination measures of liking and peer-rating measures of liking. Subjects were 87 children in three fourth-grade and two fifth-grade classrooms. Temporal stability was assessed across time intervals of 2,6, and 8 weeks. Temporal stability was examined as it traditionally has been at the group level (using Pearson product-moment correlations), and at the level at which data are normally examined for change in social-skills interventions, at the level of the individual child (using phi and Cramer's V coefficients). Assessed at the group level, the three types of peer measures were generally moderately to highly stable. Stability coefficients for individual children's scores on the peer measures, however, indicated instability at the level of the individual child. These problems regarding stability at the individual, idiographic level may be especially relevant when sociometric procedures are used as dependent measures in individual subject design studies. Conceptual and practical implications of the findings for the assessment of social-skills interventions are discussed.

Behavior Therapy↗
PubMed1994

The identification and reporting of physical abuse by physicians: a review and implications for research.

Identification and reporting of possible cases of child physical abuse are critical precursors to intervention with maltreating families. Professionals from a variety of disciplines are mandated to report suspected cases of child maltreatment. Unfortunately, not all physically abused children are identified or reported. This paper reviews the literature that has examined factors that may influence the identification and reporting of physical abuse by physicians. The literature review is preceded by an overview of the multistep, multibehavior process of identification and reporting. The factors that may influence identification and reporting are discussed according to their association with the case, physician, or setting. Future directions for research in the area of identification and reporting are suggested throughout the paper.

Adolescent↗
PubMed1993

[Dental amalgam: a toxicological evaluation].

During the latest decades the use of dental amalgam has been discussed with respect to potential toxic effects of the mercury component. In order to evaluate potential risks from this practice the recent literature is reviewed. Corrosion of fillings results in liberation of mercury. The absorption from this source in the Danish population can be estimated to be one to five micrograms/24 hrs. This exposure level is far below that accepted in occupational exposure and far below the minimum toxic level. Investigation of placental transfer of mercury has not provided any reason to avoid using amalgam during pregnancy. Micromercurialism or metal syndrome is claimed to be related to amalgam fillings. This syndrome consists mainly of complaints from the central nervous system, but also from muscles, joints and the gastrointestinal tract. The symptoms are non-specific and the documentation of the existence of such a syndrome related to mercury exposure is weak. The symptoms reported can be due to other chemical exposures, but psycho-social conditions may also play an important role. Information on disappearance of symptoms after removal of fillings may be a result of a placebo effect, which may be suggested until controlled experiments are performed. For this reason the use of chelating therapy is not indicated. Allergic contact eczema observed in few individuals is the only problem documented in connection with the use of amalgam fillings.

Brain↗
PubMed1993

Long-term consequences of childhood physical abuse.

This article reviews the literature on the long-term consequences of childhood physical abuse. Empirical research is discussed within 7 topic areas: aggressive and violent behavior, nonviolent criminal behavior, substance abuse, self-injurious and suicidal behavior, emotional problems, interpersonal problems, and academic and vocational difficulties. The studies reviewed involve primarily adult populations, although pertinent findings from literature on children and adolescents are briefly summarized. Some variables that affect the relation between physical abuse and long-term consequences are examined. These moderator variables include maltreatment characteristics, individual factors, family factors, and environmental factors. The article ends with suggestions for future research on long-term consequences and variables that may affect these outcomes.

Adolescent↗
PubMed1993

Relations between social skills and high-risk sexual interactions among adolescents. Current issues and future directions.

Researchers have begun to employ social-skills training in efforts to change the sexual behavior of adolescents. However, despite the promise of social-skills training, little is known about how social skills are related to the sexual practices of adolescents. The present article reviews the current literature and proposes a conceptual framework for understanding the relations between social skills and sexual behavior of adolescents by (a) examining the relationship between sexual activity and social skills, (b) examining the development of sexual-interaction skills and deficits, (c) summarizing what is currently known about the relations between social skills and sexual behavior, (d) discussing current issues in the assessment and treatment of sexual-interaction skills deficits, and (e) proposing some directions for needed research that will add both to our current knowledge base and to the effectiveness of applied intervention efforts.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Social-skills interventions with adolescents. Current issues and procedures.

During adolescence, the interpersonal interactions and behaviors necessary for successful social functioning become increasingly complex. In recent years, social-skills training with adolescents has made a variety of advances beyond basic skill acquisition toward techniques designed to promote generalization and maintenance of an effective interpersonal repertoire. This article reviews relevant empirical literature for current issues and procedures in social-skills training with adolescents, including use of social-skills interventions for a variety of adolescent populations and problems, use of innovative and promising intervention procedures, and issues regarding generalization and social validity of intervention procedures.

Adolescent↗
PubMed1992

Evaluation of state efforts to improve systems of care for children and adolescents with severe emotional disturbances: the CASSP (Child and Adolescent Service System Program) initial cohort study.

In 1984, the National Institute of Mental Health (NIMH) began funding its Child and Adolescent Service System Program (CASSP). In this paper, we present findings from a descriptive study of the experiences of the initial cohort of states to receive CASSP grants, conceived and conducted when the projects were approaching the end of their fifth and final year of NIMH funding. Detailed case studies were conducted of each of the 10 initial cohort projects, and the findings analyzed across projects. Data were collected from three major sources: (1) existing documentation about the projects, (2) site visits to each of the projects, and (3) information from relevant secondary sources. Findings suggest that the initial cohort projects utilized a variety of strategies and encountered a variety of barriers and facilitating factors. The projects generally implemented the intended CASSP program and did so by using a variety of strategies. The projects were judged by stakeholders in their states to have influenced the service systems in their states in the intended directions: toward a more comprehensive system of care that emphasizes community-based treatment; toward better integrated, more collaborative efforts among the state agencies involved; toward a more detailed understanding on the part of system stakeholders of the mental health problems of children and adolescents who have severe emotional disturbances, and of the influence of those problems on the lives of the children and their families; and toward increased involvement by parents and other family members in the care of these children and adolescents.

Adolescent↗
PubMed1991

Patterns of appraisal and coping across different stressor conditions among former prisoners of war with and without posttraumatic stress disorder.

Little is known about how survivors of extreme events cope with traumatic memories and subsequent negative life experiences. The present study compared (a) repatriated prisoners of war (RPWs) from World War II (WW II) with chronic posttraumatic stress disorder (PTSD), (b) RPWs without PTSD, and (c) noncombat veterans on measures of general psychological functioning, appraisal, and coping. Appraisal and coping were assessed under 2 stressor conditions: memories of war/captivity and recent negative life events. RPWs with PTSD reported poorer general psychological functioning; significantly less control over memories of WW II: and more frequent use of self-isolation, wishful thinking, self-blame, and social support in an effort to cope with these memories than did the 2 comparison groups. Fewer between-groups differences were found for the recent stressor condition. Findings are discussed in terms of factors that may explain the perseverance of coping difficulties associated with PTSD.

Adaptation, Psychological↗
PubMed1991

Effectiveness of a peer-helper intervention to increase children's social interactions. Generalization, maintenance, and social validity.

Peer-mediated interventions are being used increasingly with a variety of populations. This study examined the impact of a peer-helper intervention on the low rates of prosocial interactions of three-elementary-school children. Two peers from each child's classroom were trained as helpers to increase the social interactions of the socially isolated children. A multiple-baseline across-subjects design was used to demonstrate the impact of the intervention, and a within-subject A-B-A withdrawal design was used to assess maintenance. Behavioral observations during recess periods indicated that positive interactions with peer helpers and other classmates increased during intervention and were maintained in withdrawal and follow-up phases. Increases in positive interactions generalized to a second recess setting in which the peer-helper intervention was not introduced. The positive social interactions of all subjects reached social-validation levels of comparison groups of peers in the observation settings. Classroom sociometric assessment and teacher and self-report measures provided variable support for the effectiveness of intervention.

Behavior Therapy↗
PubMed1990

Habits with potential as disorders. Prevalence, severity, and other characteristics among college students.

Little is known about the prevalence of the various habit disorders-such as pulling out one's hair, biting fingernails, or grinding teeth--and even less is known about the prevalence of lesser habits which, if exacerbated, may be costly enough to an individual to be labeled a disorder. Such superficially "purposeless" behaviors provided the focus of the present investigation. An initial group of 142 college students completed a pilot questionnaire to identify habits to be included in a survey. The final questionnaire was then administered to 286 college students. It asked about "purposeless habits," defined as those "repeated actions that appear to serve no useful purpose but that we continue to engage in anyway." Behaviors included habits involving the mouth, face, neck, fingers, hands, legs, hair, body, clothing, and objects. In addition to assessing the nature and severity of problems caused by each habit, the stimulus conditions influencing its probability, related behaviors, and attempts to stop the habit were assessed. The kinds of behaviors that could become habit disorders were found to be quite common. Clinical and theoretical implications of the results are discussed.

Adult↗
PubMed1990

Behavioral assessment of child-abusive and neglectful families. Recent developments and current issues.

Recent developments and current issues in the behavioral assessment of child-abusive and neglectful families are described. Procedures for the assessment of target behaviors in a variety of areas that may be related to the occurrence of further maltreatment and improved family functioning are reviewed. The primary emphasis is on measures recently developed for maltreating populations, although some measures discussed were developed for nonmaltreating populations. A variety of issues that commonly arise in the assessment of maltreating families and future directions for practice and research are also addressed.

Behavior Therapy↗