Piezoelectric cantilever sensors with asymmetric anchor exhibit picogram sensitivity in liquids

We show for the first time that self-exciting and self-sensing piezoelectric cantilevers consisting only of lead zirconate titanate (PZT) measure resonance only if they are asymmetrically anchored. Symmetric-anchoring did not give rise to electrically measurable bending resonant modes in the 0-100 kHz range. Sensitivity of first and second bending mode resonances was characterized in a flow apparatus using small density changes in liquid (0.003-0.01 g/cm³) and by dodecanethiol chemisorption at 30 pM. Density change results were consistent with existing models of submerged cantilevers, and yielded mass-change sensitivity of ∼33 ng/Hz and 217 pg/Hz for the first two modes. In chemisorption experiments, where binding was localized to 1 mm² distal tip of the PZT cantilever, sensitivity improved by an order of magnitude to 2 pg/Hz and 414 fg/Hz for the same two resonant modes.     

Strategies for detecting organic liquids on soils using mid-infrared reflection spectroscopy

Stand-off monitoring for chemical spills can provide timely information for cleanup efforts, and mid-infrared reflection spectroscopy is one approach being investigated for spill detection. Using laboratory data, anomaly and target detection strategies were examined for the detection of four different low-volatility organic liquids on two different soil types. Several preprocessing and signal-weighting strategies were studied. Anomaly detection for C-H bands was good using second-derivative preprocessing and provided similar performance to that of target detection approaches such as generalized least-squares and partial least-squares, with detections at soil loads of approximately 3-6 microg/cm2 a real dosage. Good performance was also found for the detection of P=O, O-H, and C=O stretching vibrational modes, but the optimal strategy varied. The simplicity and generality of anomaly detection is attractive; however, target detection provides more capability for classification.     

Identification and correction of water velocity measurement errors associated with ultrasonic Doppler flow monitoring

Ultrasonic Doppler flow monitoring (UDFM) is used to measure water flow in pipes and channels. However, a lack of scattering particles and signal noise can cause velocity errors, particularly for smaller discharges and surface water ('clean') flows. A postprocessing methodology is presented that identifies and corrects these errors, maximising the value of existing data. Test criteria are used to identify errors. The error correction procedure defines depth–velocity relationships from cleaned 'training data' representing the range of flow conditions (including backed up) and uses these relationships to replace erroneous velocities automatically. UDFM velocity errors have been successfully identified and corrected in example applications. Routine use allows early identification of changes in instrument or site behaviour. The methodology is practical, consistent and updateable. This is a significant advancement over previous methods for correcting velocity errors, improving the applicability of UDFM.     

Systemic inflammatory response syndrome treatment by powdered sorbent pheresis: the BioLogic-Detoxification Plasma Filtration System

Systemic inflammatory response syndrome (SIRS) is one of the most common causes of death in intensive care unit patients. The detoxification plasma filtration (DTPF) system (HemoCleanse, Inc., West Lafayette, IN) combines the DT hemodiabsorption system in series with a push-pull pheresis PF system (a suspension of powdered sorbents surrounding 0.5 microm plasma filter membranes). Bidirectional plasma flow (at 80-100 ml/min) across the PF membranes provides direct contact between plasma proteins and powdered sorbents, as well as clearance of cytokines (tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6) at a rate of 15-25 ml/min, without evidence of saturation for 90 minutes. In a U.S. Food and Drug Administration approved study we treated eight patients with SIRS and organ failure with a single DTPF treatment, using powdered charcoal as sorbent in four patients and powdered charcoal and silica in four patients. Treatments proceeded for 6 hours with proper heparin anticoagulation (activated clotting time 250-300 sec) and appeared safe. All patients improved during the treatments and each had increased blood pressure and decreased need for pressor agents. Plasma cytokine levels stabilized or decreased during treatment and were significantly lower the morning after treatment. Multiple organ dysfunction (MOD) and Acute Physiology Chronic Health Evaluation II scores and organ function gradually improved in most patients, and two patients survived for more than 28 days and two for more than 14 days. The DTPF System may prove beneficial in treatment of patients with sepsis.     

Liver failure associated with mitochondrial DNA depletion

BACKGROUND/AIMS: Liver failure in infancy can result from several disorders of the mitochondrial respiratory chain. In some patients, levels of mitochondrial DNA are markedly reduced, a phenomenon referred to as mitochondrial DNA depletion. To facilitate diagnosis of this condition, we have reviewed the clinical and pathological features in five patients with mitochondrial DNA depletion. METHODS: Cases were identified by preparing Southern blots of DNA from muscle and liver, hybridising with appropriate probes and quantifying mitochondrial DNA relative to nuclear DNA. RESULTS: All our patients with mitochondrial DNA depletion died of liver failure. Other problems included hypotonia, hypoglycaemia, neurological abnormalities (including Leigh syndrome) and cataracts. Liver histology showed geographic areas of fatty change, bile duct proliferation, collapse of liver architecture and fibrosis; some cells showed decreased cytochrome oxidase activity. Muscle from three patients showed mitochondrial proliferation, with loss of cytochrome oxidase activity in some fibres but not in others; in these cases, muscle mitochondrial DNA levels were less than 5% of the median control value. The remaining two patients (from a single pedigree) had normal muscle histology and histochemistry associated with less severe depletion of mitochondrial DNA in muscle. CONCLUSIONS: Liver failure is common in patients with mitochondrial DNA depletion. Associated clinical features often include neuromuscular disease. Liver and muscle histology can be helpful in making the diagnosis. Mitochondrial DNA levels should be measured whenever liver failure is thought to have resulted from respiratory chain disease.     

Imperfect quarter-waveplate compensation in Sagnacinterferometer-type current sensors

We analyze scale factor errors associated with integrating imperfect quarter-waveplates into loop and in-line Sagnac interferometer fiber-optic current sensors. We show that relatively large imperfections in the quarter-waveplates can be tolerated in the loop version when the birefringence axes of the two quarter-waveplates are oriented 45° with respect to each other. For the in-line version, we demonstrate an electronic signal processing scheme that desensitizes the scale factor to imperfections in the quarter-waveplate     

COAL SWELLING AND CO-PROCESSING

Herrin No. 6 coal and the filter cake cleaned product from Pittsburgh No. 8 coal were co-processed with a liquid produced from the mild gasification of Wyodak coal. The co-processing studies were conducted in tubing bomb reactors and in a batch autoclave under hydrogen pressure. The reactants were thermally pretreated under helium to induce coal swelling and promote catalyst dispersion. Ferrocene and iron pentacarbonyl were used as catalyst precursors for these studies and were sulfided in situ to generate the active forms of the iron catalyst. Iron pentacarbonyl was found to form the better catalyst for conversion of these coals. Conversion of the filter cake product was found to be enhanced by pretreatment with the mild gasification liquid, because this treatment caused the coal to swell and promoted uniform dispersion of the catalyst. Higher coal conversion was observed from co-processing Herrin No. 6 coal compared to the filter cake product. This indicates the Herrin No. 6 coal would be the preferred coal to use in a commercial process. There was improvement in the quality of the oil product from co-processing Herrin No. 6 coal compared to the mild-gasification liquid.