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Biomedical subjects

W Stephens

Publications and source records attributed to W Stephens.

7 recordsLinked to original sources
PubMed2006

Evaluation of aquatic toxicities of chromium and chromium-containing effluents in reference to chromium electroplating industries.

This study evaluated aquatic toxicities of chromium and chromium-containing laboratory samples representative of effluents from chromium electroplating industries, and compared the aquatic environmental risks of hexavalent and trivalent chromium electroplating operations. Trivalent chromium electroplating has emerged as an acceptable alternative to hazardous hexavalent chromium electroplating. This process substitution has reduced the human health impact in the workplace and minimized the production of hazardous sludge regulated under the Resource Conservation and Recovery Act (RCRA). The thrust behind this research was to investigate whether trivalent chromium electroplating operations have lower adverse impacts on standardized toxicity test organisms. Ceriodaphnia dubia and Pimephales promelas were used to investigate toxicities of trivalent chromium (Cr (III)), hexavalent chromium (Cr (VI)), and industrial effluents. In agreement with previous studies, Cr (III) was found to be less toxic than Cr (VI). Despite having several organic and inorganic constituents in the effluents obtained from trivalent chromium plating baths, they exhibited less adverse effects to C. dubia than effluents obtained from hexavalent chromium electroplating baths. Thus, transition from hexavalent to trivalent chromium electroplating processes may be justified. However, because of the presence of organic constituents such as formate, oxalate, and triethylene glycol in effluents, trivalent chromium electroplating operations may face additional regulatory requirements for removal of total organic carbon.

Animals↗
PubMed2001

The potential for short rotation energy forestry on restored landfill caps.

This review examines the potential for producing biomass on restored landfills using willow and poplar species in short rotation energy forestry. In southern England, the potential production may be about 20 t ha(-1) of dry stem wood annually. However, actual yields are likely to be constrained by detrimental soil conditions, including shallow depth, compaction, low water holding capacity and poor nutritional status. These factors will affect plant growth by causing drought, waterlogging, poor soil aeration and nutritional deficiencies. Practical solutions to these problems include the correct placement and handling of the agricultural cap material, soil amelioration using tillage and the addition of organic matter (such as sewage sludge), irrigation (possibly using landfill leachate), the installation of drainage and the application of inorganic fertilizers. The correct choice of species and clone, along with good site management are also essential if economically viable yields are to be obtained. Further investigations are required to determine the actual yields that can be obtained on landfill sites using a range of management inputs.

Agriculture↗
PubMed2000

A randomized controlled trial of psychotherapy in patients with chronic functional dyspepsia.

BACKGROUND & AIMS: This study aimed to determine whether brief psychodynamic-interpersonal (PI) psychotherapy is more efficacious than a psychological control for patients with chronic, intractable functional dyspepsia (FD), and whether patients with abnormal gastric function respond differently than those with normal gastric function. METHODS: Ninety-five consecutive patients with chronic symptoms of FD who had failed to respond to conventional pharmacologic treatments were approached. Thirty-seven received PI psychotherapy, and 36 the control condition (supportive therapy). Patients completed self-report questionnaires before and after treatment and 12 months later. The patients' gastroenterologists, who were blind to the study groups, conducted independent ratings before and after treatment. Forty-nine patients also underwent a radioisotope gastric emptying study. An intention-to-treat analysis was used with baseline scores as covariates. RESULTS: At the end of treatment, there were significant advantages for PI psychotherapy compared with controls for the gastroenterologists' (P = 0.002) and patients' total symptom score (P = 0.015). One year after treatment, the symptomatic scores were similar. However, a subanalysis showed that PI therapy was superior to the control condition at 1 year, when patients with severe heartburn were excluded. There was no difference in outcome between patients with normal and abnormal gastric emptying. CONCLUSIONS: PI therapy may have both short- and long-term effects in patients with dyspepsia, but further evaluation is required. Its cost-effectiveness needs to be determined.

Adult↗
PubMed2000

Lip and vermilion reconstruction with the facial artery musculomucosal flap.

The lips are a complex laminated structure. When lost through injury or disease, they present a complex reconstructive challenge. The facial artery musculomucosal (FAMM) flap is a composite flap with features similar to those of lip tissue. In this article, the anatomy, dissection, and clinical applications for the use of the FAMM flap in lip and vermilion reconstruction are discussed. A series of 16 FAMM flaps in 13 patients is presented. Seven patients had upper-lip reconstruction and six had lower-lip reconstruction. Superiorly based FAMM flaps were used in eight patients, and eight inferiorly based flaps were performed in five patients. Three patients had bilateral, inferiorly based flaps. In summary, the FAMM flap is a local flap that can be used for lip and vermilion reconstruction. Although not identical to the lip, it has many similar features, which make it an excellent option for lip reconstruction.

Adolescent↗
PubMed1996

Fractures of the atrophic, edentulous maxilla during Le Fort I osteotomy.

The incidence of unfavorable fractures of the maxilla during Le Fort I osteotomy was compared between patients with atrophic, edentulous maxillae and patients with normal dentate maxillae. Unfavorable fractures frequently occurred in atrophic, edentulous maxillae. The most common maxillary fracture involved the junction of the horizontal plate of the palatine bone and posterior part of the maxilla. Prevention strategies and treatment options are discussed.

Adolescent↗
PubMed1992

A new intraoral flap: facial artery musculomucosal (FAMM) flap.

By combining the principles of nasolabial and buccal mucosal flaps, we have designed a new axial musculomucosal flap based on the facial artery. This flap has been designated the facial artery musculomucosal (FAMM) flap. The flap has proven to be reliable either superiorly based (retrograde flow) or inferiorly based (antegrade flow). It is versatile and has been used 18 times in 15 patients, with one failure and two partial losses. It has been used successfully to reconstruct a wide variety of difficult oronasal mucosal defects, including defects of the palate, alveolus, nasal septum, antrum, upper and lower lips, floor of the mouth, and soft palate.

Adolescent↗