Sediment Loads of Illinois Streams and Rivers

Many river projects require knowledge of the sediment load transported by the river. Suspended sediment load data for 63 locations on Illinois streams and lake sedimentation data from 24 lakes were compiled along with geomorphic information on each location. Station records were investigated, and annual and period-of-record regression equations are given for each station. Short record length (average of 2.25 years) limits the value of individual station data. Data from rivers in other midwestern states were investigated for longer-term variability. Average annual sediment loads were computed, using the period-of-record regression equation and the flow duration table for each station. These annual loads and the annual loads from the lake sedimentation studies were combined with watershed boundaries and physiographic and geomorphic data to delineate 11 Sediment Yield Areas (SYAs) within the state. Linear and multiple regression equations are presented for each SYA, and example problems outline use of the equations. Separate analyses are presented for stations on the Illinois and Mississippi Rivers.publishedpeer reviewedOpe

Sediment Yield of Streams in Northern and Central Illinois

published or submitted for publicationis peer reviewedOpe

Supramolecular Organization of the Repetitive Backbone Unit of the Streptococcus pneumoniae Pilus

Streptococcus pneumoniae, like many other Gram-positive bacteria, assembles long filamentous pili on their surface through which they adhere to host cells. Pneumococcal pili are formed by a backbone, consisting of the repetition of the major component RrgB, and two accessory proteins (RrgA and RrgC). Here we reconstruct by transmission electron microscopy and single particle image reconstruction method the three dimensional arrangement of two neighbouring RrgB molecules, which represent the minimal repetitive structural domain of the native pilus. The crystal structure of the D2-D4 domains of RrgB was solved at 1.6 Å resolution. Rigid-body fitting of the X-ray coordinates into the electron density map enabled us to define the arrangement of the backbone subunits into the S. pneumoniae native pilus. The quantitative fitting provide evidence that the pneumococcal pilus consists uniquely of RrgB monomers assembled in a head-to-tail organization. The presence of short intra-subunit linker regions connecting neighbouring domains provides the molecular basis for the intrinsic pilus flexibility

The effect of antidepressants on fertility

BACKGROUND: Information on the effects of different pharmaceuticals on fertility is sparse. Human and animal models indicate that antidepressant use could have a negative effect on fertility through alteration of levels of the neurosteroid, allopregnanolone. OBJECTIVE: The objective of this study is to assess the effects of antidepressants on the natural fertility in women. STUDY DESIGN: A secondary analysis of data from Time to Conceive, a prospective cohort study, was conducted. Women aged 30-44 without history of infertility, early in their attempts to conceive, were followed with standardized pregnancy testing until pregnancy was detected. Medication use was assessed at enrollment, daily for up to four months, and then monthly. For this analysis, discrete time regression models were created to calculate the association between antidepressant use and fecundability. Potential confounders: age, body mass index, caffeine, alcohol use, and education were included in all models. RESULTS: Ninety-two (9.6%) of 957 women reported antidepressant use while attempting to conceive. Women taking antidepressants were more likely to be non-Hispanic Caucasian (91% vs. 75%, p<0.01) and to consume alcoholic beverages (74% vs. 61%, p<0.01). Antidepressant use at enrollment had an adjusted FR of 0.86 (95% CI: 0.63-1.20). However, time varying analyses suggested that antidepressant use in a given cycle is associated with a reduced probability of conceiving in that cycle (adjusted FR 0.75 95% CI: 0.53-1.06). After adjusting for history of depression or restricting the analysis to women who reported a history of depression, the association between antidepressant use and decreased fecundability remained [adjusted FR 0.66 (95% CI 0.45-0.97) and (adjusted FR 0.64, 95% CI: 0.43-0.94), respectively]. CONCLUSION: Our data suggest that antidepressants may reduce the probability of a woman with a history of depression to conceive naturally. Future studies are needed to differentiate the extent to which this association is due to the antidepressant itself versus the underlying depression