ABSTRACT
AIMS: To quantitatively analyse the changes in group-specific rRNA levels in activated sludge as a function of sample handling and storage procedure. METHODS AND RESULTS: Quantitative membrane hybridizations with (32)P-labelled oligonucleotide probes were used to analyse the effects of different sample handling and storage conditions on the relative rRNA levels of the alpha, beta, and gamma-Proteobacteria, the Cytophaga-Flavobacteria group, and the mycolic acid-containing actinomycetes in activated sludge. Group-specific rRNA levels, expressed as percentages of total 16S rRNA detected with a universal probe, in samples maintained at room temperature significantly changed after 48 h. Group-specific rRNA levels in samples treated with chloramphenicol showed significant change after 72 h. CONCLUSIONS: Sample storage at room temperature is a viable option if freezing or analysis can be performed within 24 h, while treatment with chlorampenicol can extend that time to at least 48 h. SIGNIFICANCE AND IMPACT OF THE STUDY: Handling, shipping, and storage of environmental samples under several conditions may result in inaccurate determination of the microbial populations in microbial ecology studies.
Subject(s)
Environmental Microbiology , RNA, Bacterial/analysis , RNA, Fungal/analysis , RNA, Ribosomal/analysis , Sewage/microbiology , Actinobacteria/isolation & purification , Flavobacterium/isolation & purification , Nucleic Acid Hybridization , Preservation, Biological , Proteobacteria/isolation & purification , Time FactorsABSTRACT
The radiation environment inside a shielded volume is highly complex, consisting of both charged and neutral particles. Since the inception of human space flights, the charged particle component has received virtually all of the attention. There is however, a significant production of secondary neutrons, particularly from the aluminum structure in low earth orbiting spacecrafts. The interactions of galactic cosmic rays (GCR), and solar energetic particles with the earth's atmosphere produce a non-isotropic distribution of albedo neutrons. Inside any reasonable habitable module, the average radiation quality factor of neutrons is about 4-5 times larger than the corresponding average quality factor of charged particles. The measurement of neutrons and their energy spectra is a difficult problem due the intense sources of charged particles. This paper reviews the results of Shuttle flight experiments (made during both solar maximum and solar minimum) to measure the contribution of neutrons to the dose equivalent, as well as theoretical calculations to estimate the appropriate range of neutron energies that contribute most to the dose equivalent.
Subject(s)
Models, Theoretical , Neutrons , Radiation Monitoring/instrumentation , Space Flight/instrumentation , Cosmic Radiation , Extraterrestrial Environment , Humans , Radiation Dosage , Radiation Protection , Radiometry , Solar Activity , Spacecraft/instrumentation , Thermoluminescent DosimetryABSTRACT
The treatment of a posterior fracture-dislocation of the hip is strongly influenced by the surgeon's assessment of stability of the hip after the dislocation has been reduced. Stability is inversely related to the size of the posterior acetabular fragment. Computed tomography was used to measure the size of the fracture fragment in nine cadavera of adults. Progressive increments of bone were removed from the posterior part of the acetabular wall in sixteen hips. After each osteotomy, the hip was tested for stability and was measured by computed tomography until it became unstable. All hips from which less than 20 per cent of the posterior part of the acetabular wall was removed were stable, while those from which more than 40 per cent was removed were unstable.
Subject(s)
Acetabulum/injuries , Fractures, Bone/diagnostic imaging , Hip Dislocation/diagnostic imaging , Acetabulum/diagnostic imaging , Adult , Aged , Fractures, Bone/complications , Fractures, Bone/pathology , Hip Dislocation/complications , Hip Dislocation/pathology , Humans , Joint Instability/diagnostic imaging , Middle Aged , Osteotomy , Tomography, X-Ray ComputedABSTRACT
A case of Kaposi's sarcoma of a digit in a patient with acquired immune deficiency syndrome (AIDS) is described. The patient had what appeared to be a chronic paronychia. The paronychia tissue was excised and biopsy findings showed Kaposi's sarcoma. Kaposi's sarcoma is a multicentric, malignant, vascular tumor composed of proliferating spindle-shaped cells and capillary vessels.
Subject(s)
Acquired Immunodeficiency Syndrome/diagnosis , Fingers , Sarcoma, Kaposi/diagnosis , Adult , Chronic Disease , Diagnosis, Differential , Humans , Male , Paronychia/diagnosis , Sarcoma, Kaposi/blood supply , Sarcoma, Kaposi/pathologyABSTRACT
Economic theory suggests that consumers act to maximize their utility subject to constraints on their income and time. An individual's actions in the market (demand) generally reflect preferences based on his or her perception of utility, or welfare. Economic research has indicated that consumers purchase food, not nutrients, and that public programs and decisions concerning nutrition which have ignored consumer preferences have often been ineffective and heavily criticized. Approaches which integrate consumer demand and nutrition planning may be more successful in achieving national and institutional goals.
