Changes in bacterial species composition in enrichment cultures with various dilutions of inoculum as monitored by denaturing gradient gel electrophoresis

Denaturing gradient gel electrophoresis revealed changes in the bacterial species obtained from enrichment cultures with different inoculum dilutions. This inoculum dilution enrichment approach may facilitate the detection and isolation of a greater number of bacterial species than traditional enrichment techniques.     

Non-isotopic in situ hybridization of HPV types in cervical intraepithelial lesions in patients with AIDS

Naturally produced methane shows different delta 13C-values with respect to its origin, e.g., geological or biological. Methane-production of ruminants is considered to be the dominant source from the animal kingdom. Isotopic values of rumen methane--given in literature--range between -80/1000 and -50/1000 and are related to feed composition and also sampling techniques. Keeping cows, camels and sheep under identical feed conditions and sampling rumen gases via implanted fistuale we compared delta PDB 13C-values of methane and CO2 between the species. Referring to mean values obtained from 4 or 5 samples at different times of 11 animals (n = 47) we calculated delta PDB 13C-medians resulting in small but not significant differences within and significant differences between the species for CO2 and methane. The delta PDB 13C-differences between methane and CO2 were statistically equal within and also between the species. Therefore a linear regression of methane values on CO2 is appropriate and leads to: delta PDB 13C(methane)/1000 = 1.57 * delta PDB 13C(CO2)/1000 - 47/1000 with a correlation coefficient of r = 0.87.     

Children's beliefs about drinking

This paper reports the results of a study in which age (grade level), racial/ethnic, and gender differences in beliefs and perceived norms about drinking were examined in a multi-ethnic urban sample of 4th through 7th grade children. Results showed that older children held beliefs and perceived norms that were more favorable toward drinking than younger children. The major difference between older and younger children lay in their differential estimates of the likelihood of certain consequences occurring and not in their evaluation of these consequences of drinking. Further, older children not only displayed less motivation to comply with their parents and greater motivation to comply with their peers, but they also perceived their parents, as well as their peers, as less disapproving of drinking than did younger children. There were few gender or race/ethnicity differences at these ages in children's beliefs and perceived norms about drinking.     

Using Survey Data and Mathematical Modeling to Prioritize Water Interventions in Developing Countries

Water Resources Management - A traditional cost-benefit analysis of potential water interventions in a given locality is a laborious and time-intensive process. To help decision makers identify...     

Melanin Distribution in Human Skin: Influence of Cytoskeletal,Polarity, and Centrosome-Related Machinery of Stratum basale Keratinocytes

Melanin granules cluster within supra-nuclear caps in basal keratinocytes (KCs) of the human epidermis, where they protect KC genomic DNA against ultraviolet radiation (UVR) damage. While much is known about melanogenesis in melanocytes (MCs) and a moderate amount about melanin transfer from MC to KC, we know little about the fate of melanin once inside KCs. We recently reported that melanin fate in progenitor KCs is regulated by rare asymmetric organelle movement during mitosis. Here, we explore the role of actin, microtubules, and centrosome-associated machinery in distributing melanin within KCs. Short-term cultures of human skin explants were treated with cytochalasin-B and nocodazole to target actin filaments and microtubules, respectively. Treatment effects on melanin distribution were assessed by the Warthin–Starry stain, on centrosome-associated proteins by immunofluorescence microscopy, and on co-localisation with melanin granules by brightfield microscopy. Cytochalasin-B treatment disassembled supra-nuclear melanin caps, while nocodazole treatment moved melanin from the apical to basal KC domain. Centrosome and centriolar satellite-associated proteins showed a high degree of co-localisation with melanin. Thus, once melanin granules are transferred to KCs, their preferred apical distribution appears to be facilitated by coordinated movement of centrosomes and centriolar satellites. This mechanism may control melanin’s strategic position within UVR-exposed KCs.     

Ranking protective coatings: Laboratory vs. field experience

Environmentally protective coatings are used on a wide range of gas turbine components for survival in the harsh operating conditions of engines. A host of coatings are commercially available to protect hot-section components, ranging from simple aluminides to designer metallic overlays and ceramic thermal barrier coatings. A variety of coating-application processes are available, and they range from simple pack cementation processing to complex physical vapor deposition, which requires multimillion dollar facilities. Detailed databases are available for most coatings and coating/process combinations for a range of laboratory tests. Still, the analysis of components actually used in engines often yields surprises when compared against predicted coating behavior from laboratory testing. This paper highlights recent work to develop new laboratory tests that better simulate engine environments. Comparison of in-flight coating performance as well as industrial and factory engine testing on a range of hardware is presented along with laboratory predictions from standard testing and from recently developed cyclic burner-rig testing.     

Gingival recession and exposure of barrier membrane: effect on guided tissue regeneration of Class II furcation defects

The purpose of the present study was to evaluate the effect of barrier membrane exposure on the success of guided tissue regeneration in Class II furcation defects. Twenty-six subjects with mandibular Class II furcation defects received initial periodontal therapy followed by guided tissue regeneration surgery. The membrane was placed and the flaps were repositioned so that the membrane was totally submerged. Membranes were removed 4 to 6 weeks later, at which time the extent of their exposure was recorded. An overall improvement in all clinical parameters was observed for all subjects 1 year after surgery. Half of the patients had experienced no membrane exposure, while the other 13 subjects had experienced mild to pronounced exposure; both groups showed similar improvement in all clinical and surgical parameters. In light of the comparable results obtained in exposed sites, and the anatomic difficulties sometimes encountered in covering a membrane completely, in some of these cases the membrane may be left only partially submerged. This approach will allow for tighter occlusal "seal" of the tooth-membrane interface and preservation of the keratinized gingiva.