Current status of the Cincinnati GCL test plots

This paper describes the design, layout, construction and current status on the performance of fourteen full scale test plots targeted at assessing the internal shear strength of GCLs in landfill cover applications. Five different commercially available GCLs from four manufacturers were used in the study. Each test plot is two geosynthetic clay line roll widths wide, with lengths of 29m (95 ft) on the 3(H)-to-1(V) (horizontal-to-vertical) slopes and 20m (67 ft) on the 2(H)-to-1(V) (horizontal-to-vertical) slopes. The plots are being monitored with numerous deformation ‘telltales’ as well as subgrade and GCL moisture gages.

Two slides occurred shortly after construction. Both involved the upper surfaces of the GCLs against the overlying textured geomembranes. The slides were clearly the result of bentonite lubricated interfaces and (although of interest) did not relate to the internal shear strength focus and goals of the project.

Upon inducing internal shear stress in the GCLs by cutting all of the overlying geosynthetics, the deformations have been small except for one plot. This plot involved a unreinforced bentonite GCL, sandwiched between two geomembranes. It was sampled and found to have a large region of unexpected and excessively high moisture content. Subsequently, the test plot slid, the interface being the upper geomembrane against the bentonite of the GCL. The test plot was constructed a second time and the current response is more in keeping with the anticipated behaviour. Other than these slides, however, all of the other GCL plots appear to be stable.

If the internal stability of the GCLs continue, it can be assumed that the 2(H)-to-1(V) slopes have a factor-of-safety of 1.0 or greater. This being the case, the 3(H)-to-1(V) slopes have a factor-of-safety of 1.5 or greater. While this hypothesis is still being substantiated, it speaks well for the internal shear strength of the GCLs used in the study when properly installed. The project is ongoing as of, the writing of this paper.     

Effect of mechanical treatment on healing after third molar extraction

The aim of this study was to determine the effect of subgingival scaling and root planing on healing of the distal surface of second molars following extraction of third molars. Twenty-eight patients with contralateral erupted third molars and pocket depths greater than or equal to 3 mm on the distal surface of the second molars participated in this study. Measurements of supragingival bacterial plaque, bleeding on probing, pocket depth, and relative attachment level were performed at baseline and 2 months after treatment. Extraction of contralateral third molars was carried out simultaneously. The experimental site received thorough scaling and root planing of the distal surface of the second molar, while the control site received extraction alone. Experimental sites showed significant improvement in all clinical parameters assessed compared to the control sites. In conclusion, periodontal lesions on the distal of second molars can be significantly improved following scaling and root planing after extraction of third molars.     

Investigation of the effects of mechanical post‐processing with a colloid mill on the texture properties of stirred yogurt

Texture properties of stirred low‐fat yogurt were investigated in terms of processing after fermentation. The yogurt gel was pumped through a colloid mill at two gap widths and various peripheral velocities of the rotor. The storage modulus and yield stress were measured after 1 day and after 3 weeks, and the occurrence of syneresis was noted. The main factor for the structural degradation in the shear gap was the mean peripheral velocity of the rotor, rather than the apparent shear rate. Syneresis is related to a certain level of the storage modulus. The yield stress correlated with the storage modulus.     

Identification of peptides within a known protein sequence using COMSEQ analysis of data containing multiple sequences

Modern methods of automated protein sequence analysis can provide high-quality data with which unambiguous amino-acid sequences can be determined, but analyses are more difficult when the sample is not pure. COMSEQ and auxillary programs were written to facilitate reconciliation of multiple amino-acid sequences potentially contained in noisy data with the known amino-acid sequence of the parent protein. The COMSEQ program prints a matrix in which the first vertical column represents the known amino-acid sequence of a selected protein. Each row of the matrix contains the sequencer yield corresponding to the amino acid in the first column, with each column corresponding to the sequencing reaction cycle. A diagonal which contains net increases of amino acids for each amino acid in the known sequence identifies a peptide potentially contained within the data. The number of matches for each diagonal over the entire known sequence are tabulated and presented as an aid to locating comparisons of greatest interest. The RNDSEQ program conducts multiple analyses using randomized versions of the known amino-acid sequence and tabulates the cumulative frequencies of potential sequence matches irrespective of the true known sequence. TRANSEQ is a utility program that translates edited sequence data from common databases into files that can be used by COMSEQ and RNDSEQ. The programs have been used successfully to identify two co-sequenced peptides from bovine serum albumin, an albumin peptide sequence in the presence of hemoglobin, and to identify two sequences of rat alpha-2u-globulin that differ in their amino termini.     

Nanopore-Based Analysis of Chemically Modified DNA and Nucleic Acid Drug Targets

Nucleic acids are central figures in many of life’s key molecular processes, e.g., enzymatic activity, epigenetics/gene regulation, viral replication, aging, cancer, and other diseases. Over the past two decades, nanopores have emerged as a new tool for studying the properties of nucleic acids at the single-molecule level. In this review, we summarize the use of nanopores as sensors of nucleic acid structure, particularly for studying chemically modified and damaged DNA, and for probing the interactions of small-molecule drugs with nucleic acid targets.     

Adenovirus-mediated gene transfer of inhibitors of apoptosis protein delays apoptosis in cerebellar granule neurons

The inhibitor of apoptosis (IAP) family of antiapoptotic genes, originally discovered in baculovirus, exists in animals ranging from insects to humans. Here, we investigated the ability of IAPs to suppress cell death in both a neuronal model of apoptosis and excitotoxicity. Cerebellar granule neurons undergo apoptosis when switched from 25 to 5 mM potassium, and excitotoxic cell death in response to glutamate. We examined the endogenous expression of four members of the IAP family, X chromosome-linked IAP (XIAP), rat IAP1 (RIAP1), RIAP2, and neuronal apoptosis inhibitory protein (NAIP), by semiquantitative reverse PCR and immunoblot analysis in cultured cerebellar granule neurons. Cerebellar granule neurons express significant levels of RIAP2 mRNA and protein, but expression of RIAP1, NAIP, and XIAP was not detected. RIAP2 mRNA content and protein levels did not change when cells were switched from 25 to 5 mM potassium. To determine whether ectopic expression of IAP influenced neuronal survival after potassium withdrawal or glutamate exposure, we used recombinant adenoviral vectors to target XIAP, human IAP1 (HIAP1), HIAP2, and NAIP into cerebellar granule neurons. We demonstrate that forced expression of IAPs efficiently blocked potassium withdrawal-induced N-acetyl-Asp-Glu-Val-Asp-specific caspase activity and reduced DNA fragmentation. However, neurons were only protected from apoptosis up to 24 h after potassium withdrawal, but not at later time points, suggesting that IAPs delay but do not block apoptosis in cerebellar granule neurons. In contrast, treatment with 100 microM or 1 mM glutamate did not induce caspase activity and adenoviral-mediated expression of IAPs had no influence on subsequent excitotoxic cell death.     

Measurements of the thermal diffusivity of linear-medium-density-polyethylene/aluminium composites using a transient comparative method

Metal-powder/polymer composites are an interesting class of material because their physical properties may, within limits, be selected to match a particular application. It is therefore important to be able to measure and model the physical properties of these composites. The effective diffusivity of linear-medium-density-polyethylene/aluminium composites was measured for a range of volume fractions using a simple, transient comparative method. Effective thermal conductivity data were calculated from the effective thermal diffusivity data. The effective thermal conductivity data were modelled well by the EMT equation.