Private well groundwater quality in West Virginia, USA-2010.

The Centers for Disease Control and Prevention (CDC), in collaboration with the West Virginia Bureau of Public Health (BPH), initiated an investigation to characterize private well water quality in West Virginia. The objective was to better characterize private well water across various aquifer geologies by testing household drinking water samples and comparing them to EPA's National Primary Drinking Water Standards. The BPH selected ten counties representing three regions to capture geologically diverse areas that represent varying aquifer geology. We collected well-water samples from participating households and analyzed all water samples for 20 constituents currently monitored in public drinking-water systems. We calculated geometric means for each constituent and compared metal concentrations to EPA maximum and secondary contaminant levels by the geologic age of the rock surrounding the aquifer where the sample was obtained. All participating households (n=139) provided a water sample. We detected arsenic at levels higher than the EPA maximum contaminant level in 10 (7.2%) samples. We detected elevated radon-222 in 48 (34.5%) samples. Geologic age of the region was indicative of whether arsenic and radon-222 were present at levels that exceeded current EPA drinking water standards. We found arsenic and radon concentrations were higher in Permian aquifers compared to those of other geologic ages. Homeowners with private wells in areas with Permian aged aquifers could benefit from targeted public health messaging about potentially harmful constituent concentrations in the well water. This may help ensure proper testing and maintenance of private wells and reduce exposure to these constituents.

Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi.

In 2006, area physicians reported increases in upper respiratory symptoms in patients living in U.S. Federal Emergency Management Agency (FEMA)-supplied trailers following Hurricanes Katrina and Rita. One potential etiology to explain their symptoms included formaldehyde; however, formaldehyde levels in these occupied trailers were unknown. The objectives of our study were to identify formaldehyde levels in occupied trailers and to determine factors or characteristics of occupied trailers that could affect formaldehyde levels. A disproportionate random sample of 519 FEMA-supplied trailers was identified in Louisiana and Mississippi in November 2007. We collected and tested an air sample from each trailer for formaldehyde levels and administered a survey. Formaldehyde levels among all trailers in this study ranged from 3 parts per billion (ppb) to 590 ppb, with a geometric mean (GM) of 77 ppb [95% confidence interval (CI): 70-85; range: 3-590 ppb]. There were statistically significant differences in formaldehyde levels between trailer types (P < 0.01). The GM formaldehyde level was 81 ppb (95% CI: 72-92) among travel trailers (N = 360), 57 ppb (95% CI: 49-65) among mobile homes (N = 57), and 44 ppb (95% CI: 38-53) among park models (N = 44). Among travel trailers, formaldehyde levels varied significantly by brand. While formaldehyde levels varied by trailer type, all types tested had some levels ≥ 100 ppb.

Optical emission of biaxial ZnO-ZnS nanoribbon heterostructures.

The electronic structure and optical properties of biaxial ZnO-ZnS heterostructure nanoribbons (NRs) have been investigated using x-ray absorption near-edge structures (XANES) and x-ray excited optical luminescence (XEOL). The XANES were recorded in total electron yield and wavelength-selected photoluminescence yield across the K- and L(3,2)-edges of zinc and sulfur and the K-edge of oxygen. The XEOL from the NRs exhibit a very weak band-gap emission at 392 nm and two intense defect emissions at 491 and 531 nm. The synchrotron x-ray pulse ( approximately 100 ps, 153 ns repetition rate) was used to track the optical decay dynamics from ZnO-ZnS NR, which can be described by two lifetimes (7.6 and 55 ns). Comparison with similar measurements for ZnO and ZnS nanowires reveals that the luminescence from ZnO-ZnS NRs was dominated by the ZnO component of the NR as the ZnS component contributes little. The implication of this observation is discussed.

The effect of the surface of SnO2 nanoribbons on their luminescence using x-ray absorption and luminescence spectroscopy.

X-ray excited optical luminescence (XEOL) and x-ray absorption near-edge structure in total electron, x-ray fluorescence, and photoluminescence yields at Sn M5,4-, O K-, and Sn K-edges have been used to study the luminescence from SnO2 nanoribbons. The effect of the surface on the luminescence from SnO2 nanoribbons was studied by preferential excitation of the ions in the near-surface region and at the normal lattice positions, respectively. No noticeable change of luminescence from SnO2 nanoribbons was observed if the Sn ions in the near-surface region were excited selectively, while the luminescence intensity changes markedly when Sn or O ions at the normal lattice positions were excited across the corresponding edges. Based on the experimental results, we show that the luminescence from SnO2 nanoribbons is dominated by energy transfer from the excitation of the whole SnO2 lattice to the surface states. Surface site specificity is not observable due to its low concentration and weak absorption coefficient although the surface plays an important role in the emission as a luminescence center. The energy transfer and site specificity of the XEOL or the lack of the site specificity from a single-phase sample is discussed.

Airborne antibiotic concentrations in a swine feeding operation.

During the past 50 years, it has become common practice in the U.S. to add antibiotics to livestock feed to reduce disease and promote growth. Use of antibiotics in this manner has become the source of increasing controversy because overuse of antibiotics is suspected of leading to resistance in bacteria that cause human diseases. The purpose of this study was to measure airborne antibiotic concentrations in a swine production facility that routinely included antibiotics in feed. Samples were collected in a hog facility that included rooms devoted to farrowing, nursery, and growing operations. Analytical methods were developed to measure concentrations of the antibiotics tylosin and lincomycin in air samples. Tylosin was mixed in the feed in some of the rooms in the facility. While lincomycin was not added during this study, it had been used in this facility in the past and therefore was included in the analytical testing. Inhalable (n = 34), respirable (n = 37), and high-volume (n = 16) dust samples were collected on PVC filters over a two-month period. Tylosin concentrations were above the limit of quantification (LOQ) in 93% of the samples, while lincomycin concentrations were above the LOQ in only 9% of the samples (LOQ = 0.04 ng/sample). The average tylosin concentrations were 3, 18, and 49 ng/m3 in the respirable, inhalable, and high-volume samples, respectively. No occupational or environmental worker exposure criteria currently exist for antibiotics in air. The results of this study may be used to estimate potential swine production worker exposures and to further study the association between these exposures and health effects.

mRNA expression analysis and the molecular basis of neonatal testis defects in Dmrt1 mutant mice.

Transcriptional regulators containing the DM domain DNA binding motif have been found to control sexual differentiation in a diverse group of metazoan animals including vertebrates, insects, and nematodes, suggesting that these proteins may comprise a very ancient group of sexual regulators. Dmrt1, 1 of 7 mammalian DM domain genes, is essential for several aspects of testicular differentiation in mice. The Dmrt1 mutant phenotype becomes apparent shortly after birth, and culminates in severe testicular dysgenesis. To better understand the roles of Dmrt1 in testicular development we have performed a more detailed analysis of its mutant phenotypes, and we have used mRNA expression profiling to identify genes misregulated in the neonatal Dmrt1 mutant testis. We find that Dmrt1 mutant germ cells fail to undergo several of the normal postnatal events of germ cell development, including radial movement, mitotic proliferation, differentiation into spermatogonia, and initiation of meiosis, and they die by P14. During this period Dmrt1 mutant Sertoli cells fail to polarize and form tight junctions, and fail to cease proliferation, eventually filling the seminiferous tubules. Expression profiling at P1 and P2 in Dmrt1 mutant testes indicates defects in several important testicular signaling pathways (Gdnf, retinoic acid, TGFbeta, FSH), and detects elevated expression of the pluripotency marker Stella/Dppa3/Pgc7, providing insight into the molecular basis of Dmrt1 testis defects. This work also identifies a number of new candidate testicular regulators for further investigation.

Attraction of Anopheles (Diptera: culicidae) to volatile chemicals in Western Kenya.

Anopheles gambiae s.l. and Anopheles funestus Giles are the primary vectors of malaria in East Africa. Identification of host-location olfactory cues may increase trap sensitivity for vector control and surveillance programs. Solid-state army miniature light traps were operated near sleeping humans in huts at night without lights and augmented with the potential attractants: L-lactic acid, Limburger cheese volatiles, hexanoic acid, and carbon dioxide. Mosquito response varied between species and gender. Female An. funestus exhibited a greater response to traps baited with L-lactic acid in combination with carbon dioxide than carbon dioxide alone in two different experiments.

Dmrt1, a gene related to worm and fly sexual regulators, is required for mammalian testis differentiation.

The only molecular similarity in sex determination found so far among phyla is between the Drosophila doublesex (dsx) and Caenorhabditis elegans mab-3 genes. dsx and mab-3 contain a zinc finger-like DNA-binding motif called the DM domain, perform several related regulatory functions, and are at least partially interchangeable in vivo. A DM domain gene called Dmrt1 has been implicated in male gonad development in a variety of vertebrates, on the basis of embryonic expression and chromosomal location. Such evidence is highly suggestive of a conserved role(s) for Dmrt1 in vertebrate sexual development, but there has been no functional analysis of this gene in any species. Here we show that murine Dmrt1 is essential for postnatal testis differentiation, with mutant phenotypes similar to those caused by human chromosome 9p deletions that remove the gene. As in the case of 9p deletions, Dmrt1 is dispensable for ovary development in the mouse. Thus, as in invertebrates, a DM domain gene regulates vertebrate male development.

Speech screening of children in the dental office.

Screening for speech problems in the dental office involves less than five minutes. Procedures include the sampling of a child's pronunciations in counting activities, word responses to pictures or questions, and conversational speech situations. Use of a normative sound development chart will help judge each child's pronunciation skills. Oral diadochokinetic testing provides a means of evaluating the maturational level of the neuromotor components of the oral structures used in support of sound production. Finally, the child's ability to modify sound production after stimulation, that is, his "stimulability," adds important data for determining the child's potential for outgrowing his problem. The screening assessment of these several characteristics of speech performance, then, provides sufficient diagnostic criteria for the dentist to recommend those children for speech therapy whose error productions will not likely improve through maturation alone. In instances where examination indicates that maturation should cause spontaneous improvement of speech, the dentist would then be able to inform the parents.

Cues for screening language disorders in preschool children.

This article has described procedures and criteria a pediatrician may employ during office evaluation to identify children suspected of having a developmental language disability. Disruptions in vocabulary comprehension, vocabulary production, sentence organization, use of word forms, and articulation patterns are important cues signaling the need for referral for a speech and language evaluation. The 1970 NINDS estimate that no less than one out of every 170 children has a developmental disability affecting the development of language suggests that one or more such children with such a disability enter the pediatrician's office each week. Many of the negative consequences of this problem may be prevented or greatly reduced by early detection and appropriate referral based upon the informaion described in this article.