40463310
A rapid screening method for the detection of viable spores in powder using bioluminescence.
A rapid diagnosis of a biological threat in a powder sample is important for fi rst responders who have to make decisions on-site. The present culture-based method does not provide timely results, which is a critical barrier for a quick response when a suspicious powder sample is found. The ATP bioluminescence method, combined with a heat shock, was investigated to determine the presence of spores in powder. The results show that only spore-containing powder samples provided a dramatic increase in the bioluminescence signal after the heat shock, which induces germination of the spores. Various conditions were tested to fi nd the most effective and rapid germination procedure. Elevated temperatures (37 degrees C and 50 degrees C) were more effective in germination than room temperature. At 50 degrees C, a double-strength germinant was more effective in germination than the regular strength. The 37 degrees C/15 min procedure induced the germination of spores most effectively, while a 50 degrees C/2 min procedure provided reasonably high signals, so it could make the entire procedure even faster (< 5 min). The detection limit of the bioluminescence method is < 100 spores.
31760643
Detection of E. coli in beach water within 1 hour using immunomagnetic separation and ATP bioluminescence.
The contamination of beach waters occurs from the discharge of storm water and sanitary sewer overflows containing faecal material. Additional faecal material derives from discharge of animals and waterfowl. In order to protect public from exposure to faecal-contaminated water, it is required to test enteric indicators in beach water. The problem is that the traditional culture-based methods cannot meet this goal because it takes too long (>24 h), so the results are not available until a day later. A rapid method for testing beach water for Escherichia coli within 1 h has been developed. Immunomagnetic separation (IMS) and ATP bioluminescence were used for selective capture and quantification, respectively. This rapid method was compared to the current method (m-TEC) using beach water samples. The beach samples were prefiltered with a 20 microm pore size filter in order to remove algae, plant debris and large particles. The results showed that the prefiltration step did not trap the bacteria which were present in the original water samples. The prefiltered water was then passed through a 0.45 microm pore size filter for concentration. The deposited bacteria were resuspended and then mixed with superparamagnetic polystyrene beads (diameter of 0.6 microm) that were coated with E. coli antibodies. After IMS, the quantification of the E. coli was done by ATP bioluminescence. The results obtained with IMS-ATP bioluminescence correlated well with the plate count method (Rsq = 0.93). The detection limit of the assay was about 20 CFU/100 mL, which is well below the US EPA limits for recreational water. The entire procedure can be completed in less than 1 hour. The necessary equipment is portable and was tested on-site.
45007327
Rapid determination of bacteria in pools.
If a method for rapid determination of bacterial levels in swimming pools and whirlpools were available, bacterial health risks could be avoided before exposure occurred. Such a method would enable public-health authorities to make timely decisions about closing or reopening pools and to adjust disinfectant doses. The purpose of this study was to determine if a rapid adenosine triphosphate (ATP) bioluminescence method would serve this purpose. Bacteriological analyses were completed on samples from swimming pools and whirlpools in Washtenaw County, Michigan. The results from the ATP assay were compared with those from the conventional plate count method and were found to be highly correlated (r = .92). To assess whether a prefiltration step was necessary to delete nonbacterial ATP--which might originate from bathers' skin cells or other debris--two procedures were tested: one with prefiltration and one without prefiltration. The results for prefiltered samples were not statistically different from the results for non-prefiltered samples (p > .05), for both the heterotrophic plate counts and the ATP bioluminescence method. This study indicates that the ATP assay can estimate bacterial levels in pools within minutes and without prefiltration.
2601824
Prediction of protein tertiary structure using PROFESY, a novel method based on fragment assembly and conformational space annealing.
A novel method for ab initio prediction of protein tertiary structures, PROFESY (PROFile Enumerating SYstem), is proposed. This method utilizes the secondary structure prediction information of a query sequence and the fragment assembly procedure based on global optimization. Fifteen-residue-long fragment libraries are constructed using the secondary structure prediction method PREDICT, and fragments in these libraries are assembled to generate full-length chains of a query protein. Tertiary structures of 50 to 100 conformations are obtained by minimizing an energy function for proteins, using the conformational space annealing method that enables one to sample diverse low-lying local minima of the energy. We apply PROFESY for benchmark tests to proteins with known structures to demonstrate its feasibility. In addition, we participated in CASP5 and applied PROFESY to four new-fold targets for blind prediction. The results are quite promising, despite the fact that PROFESY was in its early stages of development. In particular, PROFESY successfully provided us the best model-one structure for the target T0161.
23741262
On the contribution of deoxy-hemoglobin to MRI gray–white matter phase contrast at high field
High field (> or =7 T) MRI studies based on signal phase have been used to improve visualization of the fine structure of the brain, most notably the major white matter fiber bundles, the gray-white matter subdivision, and the laminar cortical architecture. The observed contrast has been attributed in part to local variations in magnetic susceptibility arising from iron in storage proteins and tissue lipid. Another contribution could come from the paramagnetic blood constituent deoxy-hemoglobin, the tissue concentration of which may vary through local variations in vascular density. To investigate this possibility, we examined phase contrast between gray and white matter in rats after intravenous administration of a superparamagnetic contrast agent at various dosages. At the maximum dosage (3 mg Fe/kg), which resulted in an estimated paramagnetic susceptibility shift 4-8 times larger than deoxy-hemoglobin, we observed a negligible increase in phase contrast between gray and white matter. This result suggests that endogenous deoxy-hemoglobin has no significant contribution to phase contrast between gray and white matter.
9993310
In vitro peptide release from liquid crystalline buccal delivery systems.
Swelling and [D-Ala(2), D-Leu(5)]enkephalin (DADLE) release from the lamellar and cubic liquid crystalline phases of glyceryl monooleate (GMO) were studied using two in vitro methods, a total immersion method and a Franz cell method. The swelling of the lamellar phase and glyceryl monooleate (0% w/w water content) and DADLE release from the liquid crystalline phases were temperature dependent. The swelling ratio was greater at 20 degrees C than 37 degrees C while DADLE release increased at 37 degrees C compared to 20 degrees C for both the lamellar and cubic phases. The water uptake increased dramatically with decreasing initial water content of the liquid crystalline phases. However, DADLE release increased with increasing initial water content, which corresponded to increased viscosity. The swelling and DADLE release profiles obtained using a Franz cell method with a moist nylon membrane to mimic buccal drug release conditions were slower than the total immersion method. These results show that the swelling and DADLE release strongly depended on temperature, the initial water content of the liquid crystalline matrix and the methodology employed for determining the swelling and DADLE release.
19449141
Quantitative measures of facial expression for patients with head and neck cancer
In addition to changes in facial morphology, head and neck cancer treatment can impact the facial expression. Quantification of changes in facial expression, particularly of smiling, would enable a deeper understanding of the relationship between physical changes and psychosocial adjustment in patients being treated for facial cancer. This study proposes 48 quantitative facial expression measures, which consist of the length normalized distances and slopes between 27 manually annotated fiducial points on standard 2D clinical photographs of patients with head and neck cancer. Using the proposed measures, the maximum intensity of smiling for patients with head and neck cancer prior to their treatments was compared to that of a sample from a healthy population. A total of 7 facial expression measures captured statistically significant differences between patients with head and neck cancer and healthy individuals. These measures suggest that patients with head and neck cancer are less expressive than people without head and neck cancer. This study is the first attempt to quantify the facial expression of patients with head and neck cancer and to build a foundation for studying how surgical interventions may affect their facial expressions. Moreover, this study lays the groundwork for future investigation of the relationship between facial expression and psychosocial adjustment in cancer patients.
30852659
Microthermogravimetry using a microcantilever hot plate with integrated temperature-compensated piezoresistive strain sensors.
This paper reports thermogravimetric analysis of nanogram samples of paraffin using a microcantilever hot plate. The microcantilever hot plate has an integrated temperature-controlled heater and integrated temperature-compensated strain-sensing piezoresistors. The microcantilever vibration amplitude was measured using either a laser and a position sensitive photodiode, or using the piezoresistors. The cantilever resonance was measured as the cantilever was heated, such that the analyte mass could be measured as a function of temperature. Both optical and piezoresistive methods were employed to generate thermogravimetric curves for analytes in the range of 1-3 ng, and the results of the two methods compared well.