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Biomedical subjects

J A Clement

Publications and source records attributed to J A Clement.

At least 19 recordsLinked to original sources
PubMed2004

Iron release from corroded iron pipes in drinking water distribution systems: effect of dissolved oxygen.

Iron release from corroded iron pipes is the principal cause of "colored water" problems in drinking water distribution systems. The corrosion scales present in corroded iron pipes restrict the flow of water, and can also deteriorate the water quality. This research was focused on understanding the effect of dissolved oxygen (DO), a key water quality parameter, on iron release from the old corroded iron pipes. Corrosion scales from 70-year-old galvanized iron pipe were characterized as porous deposits of Fe(III) phases (goethite (alpha-FeOOH), magnetite (Fe(3)O(4)), and maghemite (alpha-Fe(2)O(3))) with a shell-like, dense layer near the top of the scales. High concentrations of readily soluble Fe(II) content was present inside the scales. Iron release from these corroded pipes was investigated for both flow and stagnant water conditions. Our studies confirmed that iron was released to bulk water primarily in the ferrous form. When DO was present in water, higher amounts of iron release was observed during stagnation in comparison to flowing water conditions. Additionally, it was found that increasing the DO concentration in water during stagnation reduced the amount of iron release. Our studies substantiate that increasing the concentration of oxidants in water and maintaining flowing conditions can reduce the amount of iron release from corroded iron pipes. Based on our studies, it is proposed that iron is released from corroded iron pipes by dissolution of corrosion scales, and that the microstructure and composition of corrosion scales are important parameters that can influence the amount of iron released from such systems.

Corrosion↗
PubMed2001

Physico-chemical characteristics of corrosion scales in old iron pipes.

Corrosion scales play an important role in modifying water quality in drinking water distribution systems. The corrosion scales from old iron/steel pipes were analyzed for their structure and composition. Scales were studied both before and after drying. and goethite, magnetite and lepidocrocite were identified as the primary constituents of the dried samples. High concentrations of readily soluble ferrous phases were detected in wet-scale samples. The corrosion scales had a shell-like, enveloping layer, covering porous deposits of iron oxide phases. Our studies were able to identify important differences between corrosion scales found in two different water distribution systems. Further studies are needed to establish the role of corrosion scales in the mechanism of iron release from corroded pipes.

Corrosion↗
PubMed1999

Do health professionals' attitudes interfere with the treatment of depression?

Might the attitudes of health care professionals help to explain why most persons with a depressive disorder do not receive adequate care? To assess this question, the authors surveyed the faculty and staff of a midwestern university. One hundred percent of the social workers who responded found psychotherapy or counseling to be extremely or quite effective in treating persons with a major depressive episode, compared to 55% of the psychologists and 31% of the psychiatrists. For medication, the corresponding figures were 88% of psychiatrists, 64% of psychologists, and 46% of social workers. Many respondents noted problems with interprofessional communication, while most psychiatrists felt that individuals treated by two or more professionals for their depression usually receive poorer care. If future studies indicate that nonmedical therapists who view antidepressants as relatively ineffective are less likely to refer depressed clients for medication evaluation, these findings might help to explain why many depressed individuals who could benefit from medication do not receive it. Concerns about interprofessional communication, as well as psychiatrists' beliefs about the quality of care received by persons treated by more than one professional, might also explain why joint treatment occurs less often than would be desirable. The authors discuss some of the implications that these findings may have for the education of health care professionals.

Attitude to Health↗
PubMed1997

Managed care and recovery: opportunities and challenges for psychiatric nursing.

The current crisis in mental health services is related to the "bottom line" focus of managed care. This trend as well as the consumer-led recovery movement challenge psychiatric nurses in both educational and clinical settings to carefully examine their knowledge, skills, and attitudes and to develop new partnerships with consumers in nontraditional settings to promote quality. The development of consumer-run peer support services serves as a model of consumer/professional partnerships.

Community Mental Health Services↗
PubMed1997

Quality indicators for primary mental health within managed care: a public health focus.

Primary mental health is an orientation to care that addresses mental health needs of consumers on point of first contact with caregivers. Core values, and principles drawn from a public health perspective serve as the foundation for indicators of quality within managed primary mental health. A model, illustrating the key components for quality indicators, includes stakeholder groups (consumers, families, providers, and payers), quality concerns (access, appropriateness, outcomes, and prevention), and the spectrum of clinical processes (assessment, treatment, rehabilitation, and support). Responsibility for monitoring quality is vested in these stakeholder groups. To enable them to fulfill their responsibilities, indicators are proposed in the form of checklists. The checklists assist stakeholders in evaluating the plans and services offered by managed care entities.

Community Mental Health Services↗
PubMed1993

The client with substance abuse/mental illness: mandate for collaboration.

Persons who are dually diagnosed with substance abuse and mental illness present a significant challenge to mental health professionals in all phases of treatment. The authors explore some of the factors that contribute to the confusion surrounding the care of these persons, including the prevalence and complexity of the problem; current understanding of the effect of drug-induced neurophysiological changes on the central nervous system and the cognitive function/dysfunction of persons with a major mental illness; the difficulties presented by parallel treatment systems for mental illness and chemical addiction; and the need for a shift to interdisciplinary education to integrate services into the practice setting.

Adult↗
PubMed1991

Prophylactic cranial irradiation for lung cancer patients at high risk for development of cerebral metastasis: results of a prospective randomized trial conducted by the Radiation Therapy Oncology Group.

Beginning in February 1984, 187 evaluable patients with adenocarcinoma or large cell carcinoma of the lung clinically confined to the chest were randomized to receive either conventionally fractionated thoracic irradiation alone or thoracic irradiation with concurrent, prophylactic cranial irradiation. The study population included 161 patients treated for medically or surgically inoperable primary cancers, and 26 patients undergoing adjuvant postoperative mediastinal irradiation following attempted curative resection of primary cancers found to have metastasized to hilar or mediastinal lymph nodes. Elective brain irradiation was not effective in preventing the clinical appearance of brain metastases, although the time to develop brain metastases appears to have been delayed. Eighteen of 94 patients (19%) randomized to chest irradiation alone have developed brain metastases as opposed to 8/93 patients (9%) randomized to receive prophylactic cranial irradiation (p = .10). No survival difference was observed between the treatment arms. Among the 26 patients undergoing prior resection of all gross intrathoracic disease, brain metastases were observed in 3/12 patients (25%) receiving adjuvant chest irradiation alone, compared to none of 14 receiving prophylactic cranial irradiation (p = .06). In the absence of fully reliable therapy for the primary disease, and without effective systemic therapy preventing dissemination to other, extrathoracic sites, prophylactic cranial irradiation for inoperable non-small cell lung cancer cannot be justified in routine clinical practice. Further investigation in the adjuvant, postoperative setting may be warranted.

Adenocarcinoma↗
PubMed1991

Psychiatric nursing phenomena and the construct of family boundaries.

Nursing theorists and practitioners are working to define the roles and functions of nurses more precisely in order to provide a clearer understanding of the nursing contribution to the multidisciplinary team. One method of achieving this goal is to identify and classify phenomena of interest using a nursing perspective. In this article, the multidisciplinary construct of family boundaries is explored as a phenomena of interest to psychiatric nurses. Kim's (1987) theoretical frame-work and a classification system derived by Coler and Vincent (1987) are applied to the construct and illustrated through use of a case study. Interventions relevant to type of family system boundaries are described.

Adolescent↗
PubMed1979

Tumor sterilization following high-dose pre-operative irradiation for advanced cancer of the larynx or pyriform sinus.

Twenty-two patients with advanced laryngeal cancer and 5 with advanced pyriform sinus cancer were given 51 Gy (5,100 rad) followed by surgical resection. In 10 (45%) of patients with laryngeal cancer, no tumor was found at the primary site pathologically; 15 (68%) had negative neck specimens. All of those with pyriform sinus cancer had positive specimens. Eighteen patients with laryngeal cancer are free of disease. In contrast, only 1 with pyriform sinus cancer is free of disease; 1 has had a local recurrence and 3 have had metastases. The data suggest that 51 Gy (5,100 rad) are insufficient to sterilize pyriform sinus cancer; higher doses together with adjuvant chemotherapy are needed.

Adult↗
PubMed1977

Decrease in neostriatal blood flow after D-amphetamine administration or electrical stimulation of the substantia nigra.

Local blood flow was measured in the caudate nuclei and, in some cases, other areas of rat and monkey brain by the hydrogen clearance technique. Resting values for caudate blood flow in the rat were similar to those reported elsewhere, i.e., 69 +/- 4 ml/min/100 g in the caudate. Administering D-amphetamine sulfate (0.5 mg/kg, i.p.) to rats reduced caudate flow by a maximum of about 33% after 30 min; this effect could be blocked by pretreatment with haloperidol (5.0 mg/kg, i.p.), a drug that blocks dopamine receptors. D-Amphetamine sulfate (1.5 mg/kg) also reduced caudate but not cortical blood flow in unanesthetized monkeys. Electrical stimulation of the pars compacta of the substantia nigra reduced ipsilateral caudate flow by about 25% without affecting flow in the contralateral caudate. This effect varied with the frequency and intensity of stimulation. These studies suggest that the intraparenchymal release of brain dopamine may modify intraparenchymal (local) blood flow.

Animals↗